An argument that makes use of a generalization activates the prototype for the category used in the generalization. We conducted two experiments that investigated how the activation of the prototype affects the persuasiveness of the argument. The results of the experiments suggest that the features of the prototype overshadow and partly overwrite the actual facts of the case. The case is, to some extent, judged as if it had the features of the prototype instead of the features it actually has. This prototype effect increases the persuasiveness of the argument in situations where the audience finds the judgment more warranted for the prototype than for the actual case (positive prototype effect), but decreases persuasiveness in situations where the audience finds the judgment less warranted for the prototype than for the actual case (negative prototype effect). As an example, imagine a criminal trial where a 7-year-old girl testifies as a witness for the prosecution and the defense attorney questions her reliability with the argument that “a child is less reliable as a witness”. We are interested in the persuasiveness of such generalizations, and investigate how persuasiveness is related to prototype theory some of the cases that belong to a certain category are more typical members of that category than other cases . A prototype is a mental representation that serves as a cognitive reference point for the category. The most salient features of the prototype are the first features that come to mind when the category is mentioned. The effects that prototypes have on categorization are referred to as prototype effects. That the response time for categorization is shorter for cases that fit the prototype is an example of a prototype effect  have a certain property (e.g. “less reliable as a witness”). According to es Rosch . A 7-yeat Lakoff .Previous studies on prototypes show that subjects are more likely to apply a generalization to a case if the case fits the prototype for the category used in the generalization , and applies this generalization to a specific case. If we look at cases where a certain generalization is applied, an audience will find the judgment more  Toulmin . When it Toulmin , 1990. Tagree more with the judgment, since the audience would find the argument that a 7-year-old is less reliable as a witness more warranted than the argument that a 12-year-old is less reliable. In the following, we will refer to such an effect as a positive prototype effect. In the opposite situation where the audience finds the judgment less warranted for the prototype than the actual case, a prototype that overshadows the actual facts of the case will make the audience agree less with the judgment. We will refer to this kind of effect as a negative prototype effect. The application of the category “child” to a 5-year-old could, for example, activate the prototypical 7-year-old child, to the effect that the 5-year-old is judged as if it was a 7-year-old. As a general theory, this connection between prototype effect and persuasiveness can be summarized as follows: If the audience finds the judgment more warranted for the prototype than for the actual case, the generalization will make the audience agree more with the judgment (positive prototype effect). If the audience finds the judgment equally warranted for the prototype and the actual case, the generalization will have no effect on the audience’s agreement with the judgment. If the audience finds the judgment less warranted for the prototype than for the actual case, the generalization will make the audience agree less with the judgment (negative prototype effect).The activation of the prototype has the potential to overshadow the rest of the category, so that all members of the category are perceived to have the features of the prototype Lakoff , 85. Thicategory transgression effect.One thing should be added to this theory. If we look at cases where the judgment that the “prototype child” is less reliable as a witness is more warranted than the judgment that X is less reliable as witness, we quickly realize that they not only include cases where X is 12 years old, but also cases where X is 14, 17, 19, 25, and so on. In other words, they include cases where the audience will find it inappropriate to categorize X as a “child”. In situations where a category is used inappropriately there should be no (positive) prototype effect. On the contrary, there is reason to suspect that the audience will react negatively to the inappropriate use of the category and agree less with the judgment. In the following, we will refer to this kind of negative reaction as a To test if there is a positive and negative prototype effect as described above we conducted two experiments where the participants were presented with court room scenarios and asked to what extent they agreed with an argument that made use of the generalization. The first experiment tested the generalization “a child is less reliable as a witness” and the second experiment tested the generalization “a person who is intoxicated with alcohol is less reliable as a witness”. In each experiment the results were compared with a control group where the participants were presented with the same scenario and the same argument without the generalization.http://www.mturk.com/), an online service that recruits participants to carry out online tasks, such as surveys or experimental tasks. Amazon Mechanical Turk has an increasing popularity among social scientists as a source of data . The second factor was the version of the argument made by the defense attorney .X = “4 years old”X = “9 years old”X = “12 years old”X = “14 years old”X = “17 years old”X = “19 years old”“Jason Williams is standing trial for murder. According to the prosecutor, Williams stabbed a man to death in front of a movie theatre in Atlanta, Georgia, on July 10, 2011. At the trial, the prosecution calls Jessica Miller as a witness. She is X and lives across the street from the movie theatre. She testifies that she saw the murder from her house, and identifies Williams as the killer.”The experiment was based on a court room scenario with six versions. The six versions were identical, except for the age of the witness, Jessica Miller. Each participant was presented with one of the six versions. The court room scenario read as follows:child generalization“I would like to draw your attention to one important circumstance regarding Jessica Miller. A child is less reliable as a witness. Jessica Miller is therefore less reliable as a witness.”control“I would like to draw your attention to one important circumstance regarding Jessica Miller. A X is less reliable as a witness. Jessica Miller is therefore less reliable as a witness.”X = “4-year-old”X = “9-year-old”X = “12-year-old”X = “14-year-old”X = “17-year-old”X = “19-year-old”Then, the participants were presented with an argument from the defense attorney. Each scenario had two versions of the defense attorney’s argument, one version  where the argument is based on the generalization “a child is less reliable as witness”, and one version (control) that does not use this generalization. In the control version, the word “child” is removed, and substituted with the age of Jessica Miller according to the scenario. Each participant was either given the child generalization version or the control version of the argument.After reading the given scenario and the given version of the argument the participants were asked to indicate their level of agreement with the argument on a scale from one (‘strongly disagree’) to nine (‘strongly agree’).The purpose of the experiment was to investigate the difference in agreement with the argument in the child generalization version and the control version, over the six scenarios with the different ages of Jessica Miller. On the basis of the general theory outlined in Section boundary age, and inappropriate uses where her age is above the boundary age. We predicted that the participants would react negatively to inappropriate uses, and we therefore predicted that the participants would agree less with the argument in the child generalization version than the control version above the boundary age (category transgression effect).The participants will find the use of the category “child” appropriate if it is applied to a person whose age lies within the boundaries of their conception of “child”, and the participants will find the use inappropriate if it is applied to a person who is too old to be categorized as a child. This means that a division can be made between appropriate uses, where the age of Jessica Miller is below the For cases that fall below the boundary age a division can be made between cases where Jessica Miller is older than the prototype child and cases where she is younger than the prototype child. In cases where the age of Jessica Miller is higher than the prototypical age we expected the participants to agree more with the child generalization version than the control version (positive prototype effect). In cases where the age of Jessica Miller is lower than the prototypical age we expected the participants to agree less with the child generalization version than the control version (negative prototype effect).These hypotheses are conceptually displayed in Fig. We assumed the prototypical age of a child to be around 7 years, and the boundary age to be around 15 years. On the basis of these assumptions we made the following predictions for the six scenarios. In Scenario 1 (4 years old) we predicted that the participants would agree less with the argument in the child generalization version than the control version (negative prototype effect). In Scenario 2 (9 years old), Scenario 3 (12 years old) and Scenario 4 (14 years old) we predicted that the participants would agree more with the argument in the child generalization version than the control version (positive prototype effect). In Scenario 5 (17 years old) and Scenario 6 (19 years old) we predicted that the participants would agree less with argument in the child generalization version than the control version (category transgression effect).t-test was conducted for each age.The results of the experiment are summarized in Table In Scenario 1 (4 years old) participants agreed less with the argument in the child generalization version than the control version, as predicted (negative prototype effect). In Scenario 2 (9 years old), Scenario 3 (12 years old) and Scenario 4 (14 years old) participants agreed more with the child generalization version than the control version, as predicted (positive prototype effect). In Scenario 5 (17 years old) participants agreed equally with the argument in the child generalization version and the control version. This was not predicted. In Scenario 6 (19 years old) participants agreed less with the argument in the child generalization version than the control version, as predicted. As Table A graphic representation of the results is presented in Fig. The relation between the agreement rating and the age of the witness seems to be well captured by a quadratic function where the prototype effect is manifested as a difference in curvature between the curves for the two argument versions. A quadratic function that includes an interaction between the curvature of the relationship between the agreement rating and the age of the witness is also the most parsimonious model able to capture the hypothesized relationship shown in Fig. xage). A third model (M2) that included both the age of the witness and the argument version (xarg) as explanatory variables and that accounted for the difference in curvature between the two versions of the argument. These three models are summarized below:Linear regression modeling was used to test if there was a difference in curvature and, subsequently, a region with a positive prototype effect. Three models of increasing complexity were fitted to the data with the agreement rating as the response variable: A first model (M0) that included only an intercept term. A second model (M1) that also included the age of the witness as an explanatory variable (p < 0.001). See Table The age of the witness variable was mean-centered before fitting the models to avoid multicollinearity due to the squared term. Comparing these three models using F-tests shows that M2 explains significantly more variance than M0 and M1 . But the use of generalizations can backfire. In situations where the audience finds the judgment more warranted for the actual case than for the prototype the activation of the prototype will decrease agreement (negative prototype effect). In such cases, the argument is more persuasive if the speaker refrains from the generalization and allows the facts to “speak for themselves”.As we can see in Fig. The child generalization curve and the control curve also cross each other at approximately 17 years. If our general theory is correct, this suggests that the boundary age for “child” lies somewhere around 17 years, a little higher than we assumed when we formulated our predictions for Scenario 4, 5 and 6. The use of a generalization will only result in a positive prototype effect as long as the generalization is applied to a case that belongs to the category. If it is applied to case that falls outside the category the audience will react negatively to the inappropriate use of the generalization, as we saw in Scenario 6 (19 years old).Data was collected from the same participants as the first experiment .A 6 × 2 fully factorial design was used. The first factor was the amount of wine consumed by the witness before he observed a murder . The second factor was the version of the argument made by the defense attorney  where the argument is based on the generalization “a person who is intoxicated with alcohol is less reliable as a witness”, and one version (control) that does not use this generalization. In the control version, the phrase “intoxicated with alcohol” is removed, and substituted with exact quantity of wine stated in the scenario. Each participant was either given the intoxication generalization version or the control version of the argument.After reading the given scenario and the given version of the argument the participants were asked to indicate their level of agreement with the argument on a scale from one (‘strongly disagree’) to nine (‘strongly agree’).boundary quantity for intoxication. We predicted that the participants would react negatively to inappropriate uses, and we therefore predicted that the participants would agree less with the intoxication argument than the control argument below the boundary quantity (category transgression effect). For cases that fall above the boundary quantity a division can be made between cases where the quantity is lower than the quantity consumed by a prototypical intoxicated person and cases where the quantity is higher than the prototypical quantity. In cases where the quantity is lower than the prototypical quantity we expected the participants to agree more with the intoxication argument than the control argument (positive prototype effect). In cases where the quantity is higher than the prototypical quantity we expected the participants to agree less with the intoxication argument than the control argument (negative prototype effect).The purpose of the experiment was to investigate the difference in agreement between the intoxication argument and the control argument, over the six scenarios with the different quantities of wine consumed by the witness. On the basis of the general theory outlined in Section These hypotheses are conceptually displayed in Fig. We assumed the boundary quantity to lie between one and two glasses and the quantity consumed by a prototypical intoxicated person to be about five glasses of wine. On the basis of these assumptions we made the following predictions for the six scenarios. In Scenario 1 (one glass) we predicted that the participants would agree less with the intoxication argument than the control argument (category transgression effect). In Scenario 2 (two glasses), Scenario 3 (three glasses) and Scenario 4 (four glasses) we predicted that the participants would agree more with the intoxication argument than the control argument (positive prototype effect). In Scenario 5 (six glasses) and Scenario 6 (eight glasses) we predicted that the participants would agree less with the intoxication argument than the control argument (negative prototype effect).t-test was conducted for each age.The results of the experiment are summarized in Table In Scenario 1 (one glass) participants agreed more with the intoxication argument than the control argument. This was not predicted. In Scenario 2 (two glasses) and Scenario 3 (three glasses) the participants agreed more with the intoxication argument than the control argument, as predicted (positive prototype effect). In Scenario 4 (four glasses) the participants agreed slightly less with the intoxication argument. This was not predicted. In Scenario 5 (six glasses) the participants agreed slightly more with the intoxication argument. This was not predicted either. In and Scenario 6 (eight glasses) the participants agreed less with the intoxication argument, as predicted (negative prototype effect). As Table A graphic representation of the results is presented in Fig. Some of the results matched our predictions, and some did not. There was a positive prototype effect in Scenario 2 and 3, as we predicted, but the graph Fig.  did not An explanation for the lack of a boundary quantity cross over and a category transgression effect could be that the boundary quantity does not lie between one and two glasses, as we assumed, but is, actually, below one glass. This would explain why the curves do not cross on the right hand side. To create a situation where the participants find it inappropriate to categorize Leon Kowalski as intoxicated with alcohol, you need a scenario where Kowalski has consumed less than one glass of wine, for example a scenario where he has only consumed a teaspoon of wine. Since there was no such scenario in our experiment, we missed the boundary transgression effect.That the predicted negative prototype effect on the left hand side was small and not statistically significant can be explained in a similar way. We assumed that the prototypical quantity consumed by an “intoxicated” is around five glasses, but it could be the case that it is, actually, around seven glasses. This would explain why we did not see a significant negative prototype effect in Scenario 6 (eight glasses). To see a significant effect, we should have tested a scenario with a higher quantity, e.g. a scenario where Kowalski has consumed ten glasses of wine.1Notwithstanding this incompleteness in Experiment 2, there was a positive prototype effect in Scenarios 1, 2 and 3, and the effect was statistically significant in Scenario 1 (one glass) and Scenario 2 (two glasses). Experiment 2 therefore lends further support to our general theory that an argument that makes use of a generalization activates the prototype for the category used in the generalization, to the effect that the features of the prototype overshadow and partly overwrite the actual facts of the case.The prototype effects that we saw in the experiments can be taken as a sign of irrational behavior. Let us, for example, look at the positive prototype effect in Experiment 1, Scenario 3 (12 years old). The participants who were presented with the defense attorney’s argument in the child generalization version agreed significantly more than the participants who were presented with the argument in the control version. This difference in agreement is irrational, as the facts of the case were the same and the inference was the same. Both groups where given the same scenario, with the same information about the age of Jessica Miller, and both groups were presented with an argument from the defense attorney with the inference that Jessica Miller is less reliable as a witness because of her age. The only difference between the two versions of the argument was that the control version stated that “a 12-year-old is less reliable as a witness” while the child generalization version stated that “a child is less reliable as a witness”.[MAJOR PREMISE] A 12-year-old is less reliable as a witness.[MINOR PREMISE] Jessica Miller is 12 years old.[CONCLUSION] Therefore, Jessica Miller is less reliable as a witness.control versionThat a difference in agreement between the control version and the child generalization version is irrational becomes obvious if we imagine a person, X, who is presented with both versions, and disagrees with the control version but agrees with the child generalization version. The control version can be represented as a syllogism with “12-year-old” as the middle term:modus ponens. To disagree with the argument advanced by the syllogism, X must claim that the major premise or the minor premise is incorrect. Since the correctness of the minor premise is given X must sustain that the major premise (“a 12-year-old is less reliable as a witness”) is incorrect. Bearing this in mind, let us now look at the child generalization version of the argument. The child generalization version is a syllogism where “child” serves as the middle term.[MAJOR PREMISE] A child is less reliable as a witness.[MINOR PREMISE] Jessica Miller is a child.[CONCLUSION] Therefore, Jessica Miller is less reliable as a witness.child generalization versionThe syllogism is logically valid according to fallacy of equivocation  X is forced to interpret “child” in the minor premise to include 12-year-olds, as the given age of Jessica Miller is 12 years. This means that X assigns one meaning to the term “child” in the major premise and a different meaning to the term “child” in the minor premise. X commits a fallacy of rational thinking known as the ion Mill . For a snt Naess .fallacy of equivocation has been offered by John Woods and Douglas Walton. According to Woods and Walton, people have an innocent desire to interpret premises so that they become acceptable, and this desire overpowers the ability to notice that the argument slides from one meaning to another . The effect observed in our study is not a memory effect, as the participants had information about the exact age of the witness (Experiment 1) and the amount of wine consumed (Experiment 2) right in front of them, explicitly stated above the question. Our study is concerned with evaluation, not memory. Participants were manipulated to agree with a certain evaluation (the witness is not reliable). These effects are useful for different purposes in legal rhetoric. The memory effect observed by Loftus and Palmer can be used by a skilled litigator in the questioning of a witness, to manipulate the memory of the witness. The prototype effect observed in our study can be used by the litigator in his arguments to the jury, to manipulate the jurors in their evaluation of the evidence. A litigator who seeks to prove that a car accident was caused by the defendant’s negligence can categorize the accident as a “smash” when he asks the witness how fast the defendant was going, to make the witness “remember” the speed as higher than it actually was. A litigator who seeks to undermine the reliability of a witness can categorize the witness as a “child”, to make the jurors think of her as younger than she actually is when they evaluate her reliability.This kind of manipulation can lead to incorrect and unjust verdicts. Are such litigation strategies legal? With regard to the manipulation of witness memory there is a provision in the Federal Rules of Evidence that prohibits “leading questions” (FRE 611c). According to this rule, a litigator shall not formulate questions to the witness in a way that suggests a certain answer. This rule can be used by the opposing council to voice an objection against a litigator who uses a suggestive categorization (“How fast did the car go when it smashed into the other car?”) If the judge sustains the objection, the litigator will have to reformulate his question. In contrast to this, there is no procedural rule that prohibits a litigator from using suggestive categorizations to manipulate the jurors in their evaluation of the evidence. A litigator is free to use any categorization and generalization that suits his case, and many litigators do. A litigator is free to categorize a 12 year old as a “child”, a person who has consumed one glass of wine as “intoxicated”, a person who was caught shoplifting once in his youth as a “convicted felon”, a person who has worked for 6 months as a doctor as an “experienced physician”, and so on.An argument that makes use of a generalization activates the prototype for the category used in the generalization. We conducted two experiments that investigated how the activation of the prototype affects the persuasiveness of the argument. The results of the experiments suggest that the features of the prototype overshadow and partly overwrite the actual facts of the case. The case is, to some extent, judged as if it had the features of the prototype instead of the features it actually has. This prototype effect increases the persuasiveness of the argument in situations if the audience finds the judgment more warranted for the prototype than for the actual case (positive prototype effect), but decreases persuasiveness in situations where the audience finds the judgment less warranted for the prototype than for the actual case (negative prototype effect).


The eye globe exhibits significant regional variation of mechanical behaviour. The aim of this present study is to develop a new experimental technique for testing intact eye globes in a form that is representative of in vivo conditions, and therefore suitable for determining the material properties of the complete outer ocular tunic.A test rig has been developed to provide closed-loop control of either applied intra-ocular pressure or resulting apical displacement; measurement of displacements across the external surface of the eye globe using high-resolution digital cameras and digital image correlation software; prevention of rigid-body motion and protection of the ocular surface from environmental drying. The method has been demonstrated on one human and one porcine eye globe, which were cyclically loaded. Finite element models based on specimen specific tomography, free from rotational symmetry, were used along with experimental pressure-displacement data in an inverse analysis process to derive the mechanical properties of tissue in different regions of the eye’s outer tunic.The test method enabled monitoring of mechanical response to intraocular pressure variation across the surface of the eye globe. For the two eyes tested, the method showed a gradual change in the sclera’s stiffness from a maximum at the limbus to a minimum at the posterior pole, while in the cornea the stiffness was highest at the centre and lowest in the peripheral zone. Further, for both the sclera and cornea, the load–displacement behaviour did not vary significantly between loading cycles.The first methodology capable of mechanically testing intact eye globes, with applied loads and boundary conditions that closely represent in vivo conditions is introduced. The method enables determination of the regional variation in mechanical behaviour across the ocular surface. Simulating the response of the ocular vessel to external and internal forces is of particular interest as it can lead to developments in diagnostic and corrective procedures for various degenerative visual conditions such as glaucoma, keratoconus and myopia –6. AccurThe multi-faceted behaviour of corneoscleral tissue can be described as anisotropic, hyperelastic , 8 and vSeveral biomechanical studies have been conducted on ex vivo ocular tissues employing mainly uniaxial tension tests –26 and iIn this study, a case is made for applying the inflation concept on intact eye globes to avoid the shortfalls of both the uniaxial testing of tissue strips and the inflation testing of corneal buttons or scleral cups. While globe inflation testing has been attempted before, the studies were limited to observations of parts of the eye globe; such as posterior sclera , anterioThe present study extends behaviour observations to the whole ocular surface, attempts to use more physiologic boundary conditions and illustrates the new method through an initial experimental test programme involving cyclic inflation of intact eye globes. Attention has been given, as much as possible, to ensure consistency with the in vivo conditions of the eye in order to avoid the main sources of error affecting the reliability of the target material properties of the ocular tissue.In addition to the experimental testing method, the procedure includes a numerical inverse analysis method that uses the experimental pressure-deformation data to determine the tissue’s hyperelastic stress–strain properties across the ocular surface.Instrumentation has been developed to support, protect and monitor the intact eye globe while allowing simple computer control of test procedure and data collection. A diagram of the test rig is provided in Fig. A 2 × 50 mm hypodermic needle was inserted into the ocular cavity through the posterior pole, passed through the back wall of the glass box and its support system and connected through a pipe network to a motor-driven syringe pump, which provided changes in the applied pressure. Fixed at the same elevation as the centre of the eye was a pressure transducer  that measured the applied pressure with a 0.1 mmHg resolution.The deformation of the eye that resulted from changing the internal pressure by the syringe pump was measured using a system of three high-resolution, digital cameras  with 100 mm  macro lenses that were mounted on a support frame designed for both access and rigidity. The cameras were positioned around the equator of the eye globe facing perpendicular to the sides of the triangular support box. The camera images were initially used to obtain sufficient topography information to construct the eye-specific FE numerical model of the test specimen used in later inverse analysis. The cameras  measured the displacement at the cornea’s apex with 1 μm resolution. This addition to the test rig helped (1) enable the conduct of the test while controlling the displacement at the apex, and (2) provided a direct measurement of an important displacement parameter that aided the validation of the deformation measurements obtained from analysis of the camera images.p) or resulting displacement (δ) at the corneal apex using a non-linear, proportional-gain, control of the motorised syringe pump. Trials have been conducted to ensure the system provided stable rates of change in pressure (dp/dt) or displacement (dδ/dt). During the test, applied pressure and displacement at the corneal apex were recorded every 50 ms, and filtered through a 4 Hz low-pass filter, which was assessed to be a suitable sampling rate at the calibration trials. Further, the LabVIEW software triggered all cameras simultaneously at specified times during the test, and the images were collected and used later in the construction of specimen-specific eye models and determining the distribution of deformation across the ocular surface.A LabVIEW program has been developed to record data and control the test using a closed-loop system through a data acquisition card . The control and data acquisition system is shown schematically in Fig. k’ was measured using an Instron uniaxial machine fitted with a 10 N load cell and found to be linear of the value k' = F/(δA) = 0.0001 N/mm3, where F is the applied force, δ the resulting deformation, and A the cross-sectional area of gelatine material.The eye specimen was cast into a gelatine support, which was produced from Type-A gelatine flakes derived from porcine skin (Sigma-Aldrich cat. No. G2500). This particular gelatine was chosen from trials for its clarity and low spring stiffness and because it had been reported not to chemically alter collagen based tissue . In ordeFinite element analysis (FEA) was conducted using the non-linear solver Abaqus/Standard 6.13  to determine the effect of this stiffness on the deformation of an inflating eye globe. The topography of the model was described by: a corneal radius (7.8 mm) and shape factor (0.82); a sclera radius (11.5 mm); a central corneal thickness, CCT  and a p3 (<0.01 %) less than the control model, once both were loaded to 30 mmHg. Based on these results, the spring effect of the gelatine on the experiments was considered negligible.Comparison between a control finite element model (FEM) with no gelatine support and a model with an external spring condition matching the measured spring stiffness of the gelatine was conducted. Table The laser displacement device uses an optical triangulation position sensor to determine the distance to a near object by the recorded change in angle between the output beam and the reflected beam. Altering the media the laser travels through consequently alters the refractive angle, which in turn affects the triangulation angle. A linear displacement calibrator with a resolution of 1 μm was used to recalibrate the laser displacement transducer through the glass box and gelatine by directly controlling and changing the distance measured by the laser. The relationship between the known relative distance and the relative distance measurements from the laser provided the calibration factor to correct the laser readings. The resulting root mean square (RMS) error after recalibration was 2.7 μm.DIC is an established technique that relies on the analysis of successive camera images taken for a test specimen to derive the deformation distribution across the specimen surface . This teDiscrete speckles of cellulose-based paints were chosen for their stability, rapid solvent evaporation and organic nature. The speckles optimised the DIC output and did not provide another surface layer to the specimens. Uniaxial tests were performed on corneal tissue, both with and without applied media, to ensure no mechanical effects resulted from this process.Referring back to the physical setup described in Fig. During the test, all deformations were measured relative to the single fixed position i.e., the junction with the inflation needle. However, if this measurement was used to perform inverse modelling, the deformation at the anterior of the eye would be a function of the deformation locally and the deformation of the posterior part, therefore, all modelling errors describing the response of the posterior region would be carried forward to the analysis of the anterior region. To rectify this, the position from which the relative displacement was measured was redefined. This process is diagrammatically described in Fig. Accurate measurements of deformation and loading, and accurate representation of boundary conditions are required to derive representative material properties from an inverse analysis process. Additionally, the reliability of the derived material properties is reliant on an accurate representation of the geometry of the specimen within the finite element simulation. This section describes the method used to recreate the geometry of the specimen in the form of an FEM and the method used to quantify and minimise errors.The geometry of the models was constructed as an orphan mesh for use with Abaqus using bespoke software. The external topography was created from six individual meridian profiles from the three cameras at IOP = 2 mmHg. These profiles were calibrated and aligned with each other in the 3D space based on the common polar axis, which was defined by the needle. The internal topography was based on the external topography and eight meridian profiles of discrete thickness measurements. The thickness was measured at 2 mm intervals along each meridian from pole to pole . The intThe lamina cribrosa was represented by a thinned section of the FEM. The central thickness of this section is fifty percent less than the value in surrounding tissue; in addition the material was represented with a Young’s modulus of 0.32 MPa and a Poisson’s ratio of 0.49 . BoundarOcular material behaviour parameters were derived from the experimental data using HEEDS , in conjunction with Abaqus. The optimisation was based on determining material parameters that provided the best possible match between applied pressure and deformation results, as obtained experimentally and predicted numerically. The optimisation was based on the SHERPA algorithm that utilises Monte Carlo sampling to enhance the robustness and uniqueness of the solution. The algorithm’s objective function was to minimise the RMS error between the sets of experimental and numerical data as percentages of the final deformation at the relevant location;N is the number of pressure levels, M = 26 is the number of measurement locations and δi,j is the deformation at each particular pressure, at each location. As the deformation was measured relative to the geometry at IOP = 2 mmHg, FEA was performed over two stages. The first stage elevated IOP to match that of the initial pressure of the experiment, and the second stage increased IOP to the final pressure. The deformation from the FEA  was recorded relative to the beginning of the second stage.where W:The numerical model used to describe the material behaviour of the ocular tissue during loading was the hyperelastic Ogden model, utilised in a number of previous studies on soft tissue –45, and λkα'  are the deviatoric principal stretches equal to J− 1/3 × λk; J = λx ⋅ λy ⋅ λz where λx, λy, λz are the principal stretches in the three main Cartesian directions. The material parameters denoting the strain hardening exponent and the shear modulus are αi and μi(i = 1 … N) respectively, where N is the function order. The product of stretch in all three directions, J = λx ⋅ λy ⋅ λz = 1, following the approximation that ocular tissue is an almost incompressible material [αi and i represented the output of the inverse modelling process described above. The use of a first order material model, N = 1, reduced computation time during the modelling procedure by reducing the number of variables requiring optimisation and was found to produce stable results.where material , 47. Thep < 4s), where p is the optimized parameter and s is the best fit parameter value.In addition to the utilisation of Monte Carlo sampling to enhance uniqueness, uniqueness was ensured by repeating the inverse analysis twelve times. For each run, the baseline and boundaries of the solution space where altered within sensible but exploratory limits, , and the associated deviation from in vivo strain distributions, have led in other test methods to the necessity for preconditioning before a consistent, cyclic stress–strain behaviour is observed . The reaThe limited experimental testing of one human and one porcine eye, included in this study, was presented mainly to illustrate the whole-globe inflation and the results that can be obtained from it. While the results presented show interesting trends that could only be obtained through whole-globe testing, they will need confirmation in studies involving larger numbers of test specimens.In the test conducted on a human eye, inverse analysis allowed observation of high stiffness at the limbal region and the ring of scleral tissue immediately adjacent to it, reducing gradually towards the posterior pole. At the same time, the central cornea had a higher stiffness than the peripheral cornea, and both were much more compliant than the limbus. This behaviour is compatible with trends in material properties reported in previous studies , 27, 33.The inverse analysis included within the method description and performed in this study assumed isotropy of material behaviour. This is despite the fact that the mechanical response of ocular tissue is known to be anisotropic and that a number of studies have utilised characteristic anisotropic microstructure arrangements , 52 in nThe results obtained immediately adjacent to the posterior pole may have been compromised by the insertion of the inflation needle. Due to the process of reorienting the DIC measurement such that the origin was no longer located at the posterior pole, the potential inaccuracies in this area did not compound smaller errors in the derivation of material parameters elsewhere across the eye globe. The response to increases in IOP is a global response and errors in the representation of one region will always affect another region. However, it is suggested that this transfer of the origin to the limbal region has improved the reliability in the derivation of properties particularly at the limbus and across the cornea as this effect has been limited.For the porcine eye, while the experimental procedure was applied successfully, the inverse analysis produced larger errors due to considerable latitudinal variation in behaviour within each of the model’s nine regions. This is most prominent in the mid cornea, limbal and equatorial regions. While the non-rotational representation of the specimen specific geometry was considered, the FEM was limited to rotationally symmetric material representation, which meant that the variation in stiffness could only arise due to the slightly irregular geometry around latitudinal regions. However, it is clear from the fitting of numerical to experimental data in the porcine eye that variations in geometry alone did not entirely represent the variation in stiffness, suggesting the need to consider possibly significant variations in material stiffness around these latitudinal regions when modelling porcine eye globes. This makes it more important to consider the anisotropic fibril distribution across the ocular surface once this information becomes available.The study demonstrated that preconditioning cycles may not be required to obtain consistent load-deformation behaviour in globe inflation testing. This is a result of the test procedure providing a strain distribution that closely represents that of the in vivo eye and does not involve significant surgical manipulation as those factors would otherwise result in fibre re-orientation, and hence tissue stiffening, between successive preconditioning cycles. These findings are consistent with an earlier study on sections of non-human ocular tissue .While the test procedure presented in this study represents a significant improvement in the ability to derive regional stiffness variations consistent with the in vivo eye, the method including the experimental testing and associated data analysis is substantially more demanding and more complex than uniaxial strip extensometry and inflation of separated corneas and scleras. However, despite these challenges and the difficulties in acquiring whole eye globes for research, the novelty of the technique and the more comprehensive data it offers, make the method invaluable in ocular material characterisation, especially as microstructure data covering the whole ocular surface becomes available.


P < 0.01) in response to both stressors, and these increases were greater (P < 0.01) than that in the lactating animals. For lactating ewes with lambs present but unable to be suckled, cortisol increased (P < 0.05) in response to both stressors with a greater response to barking dogs (P < 0.05). For lactating ewes with lambs present and able to be suckled, cortisol increased (P < 0.01) in response to barking dogs only. Plasma oxytocin was greater (P < 0.01) in lactating ewes than in nonlactating ewes and did not change in response to the stressors. In conclusion, lactating ewes are likely to have a greater HPA axis response to a stressor that may be perceived to threaten the welfare of themselves and/or their offspring. The role of oxytocin in attenuation of the HPA axis to stress in sheep is unclear from the current research and requires further investigation.Activation of the hypothalamo-pituitary-adrenal (HPA) axis by psychosocial stress is attenuated during lactation. We tested the hypothesis that lactating ewes will have attenuated HPA axis responses to isolation and restraint but will have greater responses to predator stress in the form of barking dogs. We imposed two 4 h stressors: psychosocial stress (isolation and restraint of ewes) and predator stress (barking dogs). Blood was collected intravenous every 10 min from nonlactating ewes (n = 6), lactating ewes with lambs present but not able to be suckled (n = 6), and lactating ewes with lambs present and able to be suckled (n = 6). Plasma cortisol and oxytocin were measured. For nonlactating ewes, cortisol increased ( •The response of the hypothalamo-pituitary-adrenal axis to stress is attenuated during lactation in sheep.•The extent of this attenuation is influenced by the opportunity to suckle lambs and the type of stressor.•Stressors that pose an immediate threat to the offspring evoke greater stress responses. The 18 ewes consisted of 6 that were not lactating (nonlactating) and 12 that were lactating. The ewes were chosen randomly from a flock of 200 ewes to which rams had been introduced for 8 wk during the normal breeding season. The ewes were undergoing natural estrous cycles during this time. Lactating ewes were randomly selected from ewes that gave birth to a single lamb, and the experiment was conducted when the lambs were 6 wk old. Nonlactating ewes were flock mates that failed to lamb.All sheep were housed in adjacent individual pens (0.5 × 1.2 m) for 1 wk before the experiment. Indwelling catheters  were placed in 1 jugular vein of each ewe the day before sampling and treatment. The jugular vein was located through palpation of the neck. The catheter inserted directly through the skin into the jugular vein, verified by the presence of venous blood in the catheter. A single suture was used to fix the catheter to the skin. Patency of each catheter was maintained by flushing with 5-mL heparinized saline (0.5%) at each time of sampling. The catheter was removed after each sampling period.2.2The ewes were divided into the following groups (n = 6 ewes per group): (1) nonlactating ewes, (2) lactating ewes with lambs present but unable to be suckled, and (3) lactating ewes with lambs present and able to be suckled. For lactating ewes with lambs present but unable to be suckled, the lambs were present in the pens with their mothers. A partition prevented suckling but allowed auditory, olfactory, and limited tactile stimulation between the lamb and mother Animals were exposed to stress in random order over 2 d, with blood samples for individual animals collected over 8 h. The second stress was imposed after a 14-d rest period. Different stressors were imposed on all animals on each of the experimental days. One stressor was isolation and restraint stress that was imposed for 4 h. The other consisted of 3 dogs barking for 5 min continuously, that was imposed every hour on the hour for 4 h.On each experimental day, blood samples (5 mL) were collected every 10 min for 8 h. After 4 h of sampling, the stressor was imposed for the remaining 4 h. Isolation and restraint stress was imposed as previously described g). Plasma was decanted immediately after centrifugation and stored at −20°C until assay. Plasma concentrations of cortisol and oxytocin were assayed.Blood was held on ice for up to 10 min, then, plasma was harvested from the blood by centrifugation at 4°C for 10 min at 3000 rpm  following a similar procedure to that described by Marazziti 2.4Normality of the data sets was tested using the Kolmogorov–Smirnov statistic, and homogeneity of variance was tested using Levene's test. No transformations were necessary.Repeated measures analysis of variance was used to compare the plasma concentrations of cortisol and oxytocin within and between groups and stressors. The within subjects factors were stress (isolation and restraint or barking dogs) and the sampling times (time). The between subjects factor was group . Individual animals were also included as factors. Three analyses were conducted. One was on all data, and another was on mean concentrations. The third analysis was on proportional increase in plasma concentrations in response to stress. The analysis on all data allowed comparisons over time, that is within subjects, and overall between subjects. Analysis on the mean concentrations allowed for comparison between pre- and post-treatment. The key comparison to test the hypothesis that “lactating ewes will have attenuated cortisol responses to isolation and restraint but will have greater responses to predator stress in the form of barking dogs” is the cortisol responses in the lactating ewes when subjected to isolation and restraint relative to barking dogs. These are the cortisol responses over time and the concentrations of cortisol between these treatments. To establish the importance of suckling in influencing these responses, the key comparison is plasma cortisol to both stressors in lactating ewes with lambs present and unable to suck and lambs present and able to suck. Comparisons were also made between nonlactating ewes and lactating ewes to confirm that lactation attenuates HPA axis responses to stress.Because it is well appreciated that there can be activation of the HPA axis in ewes at the commencement of sampling 33.1P < 0.001) in nonlactating ewes than both groups of lactating ewes, irrespective of the stage of the experiment (P < 0.001).Mean overall plasma concentrations of cortisol differed between groups and were greater (periment . There wP < 0.01) from the pre-treatment period to the period of isolation and restraint stress (P < 0.001) in plasma cortisol with each introduction of the barking dogs . On the day of isolation and restraint stress, there was an increase (P < 0.01) in plasma cortisol during isolation and restraint (P < 0.01) with each introduction of the barking dogs returning to baseline within 30 to40 min (P < 0.05) than during the period of isolation and restraint , but there was a time × stress interaction (P = 0.008). Further partitioning of the analysis revealed that plasma cortisol did not vary throughout the day of isolation and restraint stress  in response to barking dogs than isolation and restraint  than that in both the lactating ewes with lambs present but unable to be suckled and lactating ewes with lambs present and able to be suckled (P < 0.01) in lactating ewes with lambs present but unable to be suckled than that in lactating ewes with lambs present and able to be suckled  with the mean (±SEM) plasma concentrations of oxytocin (ng/mL) being greater in lactating ewes (1.5 ± 0.02) than that in the nonlactating ewes (0.8 ± 0.02).Differences were not detected in overall plasma concentrations of oxytocin among lactating ewes regardless of ability of lambs to suck. Nevertheless, there was a between groups effect (P = 0.002) and the lactating ewes with lambs present and able to be suckled (P = 0.047).There were no consistent effects of time on plasma concentrations of oxytocin for any of the groups with no discernible difference between the pre-treatment period and the period of stress. For the nonlactating ewes, there was also no difference in plasma concentrations of oxytocin on the day of isolation and restraint stress and the day of barking dogs . In cont4It is clear from these results that the responsiveness of the HPA axis to stress in ewes is attenuated during lactation and that the extent of this attenuation is influenced by the type of stressor. As expected, the cortisol responses to both isolation and restraint and barking dogs were greater in nonlactating ewes than that in lactating ewes. Furthermore, there was greater attenuation in the cortisol response to isolation and restraint in lactating ewes with lambs present and able to be suckled than that in lactating ewes with lambs present but unable to be suckled. These findings support our previous research with ewes The different cortisol responses in lactating ewes to isolation and restraint and barking dogs support the contention that stress responses in lactating females will vary depending on the extent to which behavioral and physiological actions of the dam are required to protect the offspring in a threatening environment. As indicated in the introduction, isolation and restraint of ewes when their lambs remain with them is unlikely to be perceived as posing a major direct threat to the offspring. In contrast, barking dogs are likely to be identified as a greater threat, and this would require physiological and behavioral adaptions to allow the ewe to protect her offspring and herself. Activation of the HPA axis, and other stress systems, will acutely stimulate a range of autonomic, hormonal, and behavioral processes in the ewe to maximize survival The specific mechanisms for divergent activation of the HPA axis in lactating ewes with lambs present and able to suck in response to isolation and restraint and barking dogs are unknown. Nevertheless, some of the underlying mechanisms that cause lactation to be a generally stress hyporesponsive condition have been identified. These include reduced synthesis and secretion of CRH and AVP from the PVN because of reduced activity of neural excitatory inputs and increased negative inputs, decreased pituitary responsiveness to CRH and AVP, decreased adrenal responsiveness to ACTH, and altered negative feedback by glucocorticoids (for reviews see The reasons for the lack of oxytocin response to stress in the present study are unknown. One possibility is that the sampling regimen was insufficient to detect small increases in oxytocin. Furthermore, we were likely to be measuring mostly peripheral oxytocin, secreted from the posterior pituitary, whereas it may well be central oxytocin that is predominantly responsible for attenuating effects on the activity of the HPA axis Our findings are directly applicable to sheep and most likely other domestic livestock species because they demonstrate that stress responses for ewes likely differ depending on whether they are lactating or not and the type of stressor. In terms of animal welfare, this means that separate or tailored protocols that address management during each stage of production may be valuable. Indeed, practices that may evoke a stress response in a nonlactating ewe may not evoke the same stress response in a lactating ewe, and our data are good evidence of this. In addition, our data suggest that anything that a ewe perceives as a threat to her lambs will evoke a greater stress response during lactation than a stressor that is not perceived as a threat to her lambs. An evaluation of other predator stressors similar to that of a barking dog, like the presence of a human, may be valuable in understanding stress responses and animal welfare in production animals.5In conclusion, the response of the HPA axis to stress is attenuated during lactation in sheep, but the extent of the attenuation is influenced by the opportunity to suckle lambs and the type of stressor. The attenuation of the HPA axis is maximized when there is an opportunity to suckle lambs. Furthermore, stressors that potentially threaten the wellbeing of the ewe and her lamb will evoke greater responses of the HPA axis. Thus, under conditions where a stress response is required for survival, or to maximize wellbeing, there is less hyporesponsiveness of the HPA axis than in less threatening circumstances. The mechanisms are unknown, including the role of oxytocin. We have shown here that lactating ewes have greater circulating levels of oxytocin and lower levels of cortisol in response to stress than nonlactating ewes, but there were no changes in plasma oxytocin in response to stress. There is now a solid platform on which to build further research to understand, and potentially manipulate, the mechanisms involved in attenuation of the HPA axis during lactation.


The rigid support of intracranial probes can be difficult when using animal models, as mounting devices suitable for the probes are either not available, or designed for human use and not suitable in animal skulls. A cheap and reliable mounting device for securing intracranial probes in large animal models is described.Using commonly available clinical consumables, a universal mounting device for securing intracranial probes to the skull of large animals was developed and tested.A simply made mounting device to hold a variety of probes from 500 μm to 1.3 mm in diameter to the skull was developed. The device was used to hold probes to the skulls of sheep for up to 18 h. No adhesives or cements were used.The described device provides a reliable method of securing probes to the skull of animals. The monitoring of various physiological and biochemical parameters at tissue level is essential in many animal models of intensive care. While monitoring probes may be sutured easily to many organs, the brain presents unique challenges. Intracranial monitoring probes are usually rigidly mounted to the skull to prevent movement of the probe tip within the soft tissue of the brain. Such movement may cause localised tissue trauma and invalid data.Many of the probes used in animal models may not be designed specifically for either intracranial or animal use, and suitable mounting solutions may not be available. Probes and mountings designed for human use may be too long for use in the animal brain or not attach rigidly to the thinner skull. A universal design for use on the very thin skulls of small animals such as rabbits and piglets has been presented . This orPresented here is a simplified probe mounting device suitable for use in models using larger animals with a thicker skull. Like the previous design, it also utilises common clinical consumables in its construction. However, only a single modification is required, and the use of adhesives and cements is avoided.The mount was constructed using components from the Interlink® needleless system from Baxter  or BD . Using a hobby tool  with a thin cutting blade, the female threaded section around the luer tip of the injection site (Baxter #2 N3399) was removed as shown in Figure Depending on the nature of the probe, the device may be used in a number of ways as shown in Figures Longer probes, such as those based on fibre optics, may be introduced as shown in Figure To mount the device in the skull, the scalp is dissected away and an 11/64″ (4.32 mm) drill is used to make a hole in the skull, such that the probe tip will be positioned at the desired location. When approaching the inner surface of the skull, only minimal pressure should be used to prevent damage to the brain. A blunt needle may be used as a probe to test whether the skull has been penetrated and the dura reached. The skull thickness is checked and, if the skull is thinner than the length of the luer tip, the tip may be shortened before use. In animals with very thick skulls, the luer taper may not fully penetrate the skull; this does not interfere with the operation of the device. When the dura is reached, a sharp 19G needle is used to make a hole for the probe tip. The assembled device is inserted into the drilled hole and pushed in until the flange of the fitting is flushed with the skull. The taper on the luer tip of the device is firmly held to the skull by friction. No cement is needed if the hole is drilled carefully and remains circular. Sutures may be used to close the skin around the device, if necessary.The mounting device has been used to hold a range of probes in a number of different animal models of intensive care including studies of brain death, traumatic brain injury, and sepsis. Adult sheep, either ewes or wethers, were used in all studies. All animal studies were approved by the Queensland University of Technology Animal Ethics Committee.Needle-based intracranial pressure probes, 1.3 mm diameter: these are introduced as shown in Figure Laser Doppler flow needle probes, 1 mm diameter : these are introduced as shown in Figure Single-fibre laser Doppler flow probes, 500 μm diameter : these are introduced as shown in Figure Tissue oxygen probes, 650 μm diameter : these are introduced as shown in Figure The following probes have been used with this mounting device:Over 50 of the devices have been used to date, all in adult sheep. No probes were damaged during insertion into, or removal from, the mounting device. In 12 sheep, two devices have been used simultaneously, one in each cerebral hemisphere. Dwell time has ranged from 8 to 18 h. In no case was a mounting device dislodged, even when repositioning the animal, and there were no instances of poor signal quality attributable to probe movement.A simple mounting device for attaching intracranial probes to the skull of large animals has been developed and used in ovine models of intensive care. The device can secure a wide range of probes, within the limitations of size and nature of the probe.With the use of a needle as an introducer, the maximum probe size is limited to the inside diameter of a needle that will pass through the luer tip, approximately 2.2 mm. Using the threaded lock cannula is easier and safer, but the probe diameter is limited to the inside diameter of the cannula, approximately 1.3 mm.The polymer ‘bung’ within the device is designed to reseal after being penetrated by a needle or thread lock cannula. As such, the ‘bung’ is capable of gripping the probe with considerable force, and this may obstruct the lumen if used to secure microdialysis or other catheters.The device is held to the skull by friction between the skull and the tapered luer fitting. If further securement is needed, a small amount of cyanoacrylate adhesive can be used on the taper and/or the flange of the device. Closing the skin around with device will also assist in preventing dislodgement.The mounting device presented here is considerably easier to make than the previously presented design. It is not necessary to use adhesive in the manufacture of the device. As no cement is used to hold the device to the skull, there is no need to hold the device carefully aligned to a predrilled hole and steady against the skull while the cement hardens.


Plasmodium falciparum and Plasmodium vivax malaria. The malaria transmission process is highly influenced by factors such as spatial and temporal heterogeneities of the environment and individual-based characteristics of mosquitoes and humans populations. All these determinant factors can be simulated effectively trough agent-based models.The Amazon environment has been exposed in the last decades to radical changes that have been accompanied by a remarkable rise of both Plasmodium  are simulated in a spatially explicit representation of the environment around the village. The model environment includes: climate, people houses positions and elevation. A representation of changes in the mosquito breeding areas extension caused by the river flooding is also included in the simulation environment.This paper presents a validated agent-based model of local-scale malaria transmission. The model reproduces the environment of a typical riverine village in the northern Peruvian Amazon, where the malaria transmission is highly seasonal and apparently associated with flooding of large areas caused by the neighbouring river. Agents representing humans, mosquitoes and the two species of A calibration process was carried out to reproduce the variations of the malaria monthly incidence over a period of 3 years. The calibrated model is also able to reproduce the spatial heterogeneities of local scale malaria transmission. A “what if” eradication strategy scenario is proposed: if the mosquito breeding sites are eliminated through mosquito larva habitat management in a buffer area extended at least 200 m around the village, the malaria transmission is eradicated from the village.The use of agent-based models can reproduce effectively the spatiotemporal variations of the malaria transmission in a low endemicity environment dominated by river floodings like in the Amazon. Anopheles darlingi . Padre Cocha is located 5.5 km from the city of Iquitos, the capital of the district Loreto in Peru. The land cover around Padre Cocha is typical of a peri-urban area in the Peruvian Amazon: much of the cover is constituted by cleared areas that mix with secondary forest growth. Part of the land around Padre Cocha is covered all throughout the year by permanent stretches of water that include a big lagoon  and December (282 mm) and lowest rainfall intensity in August (165 mm). The average annual temperature is 26.7 °C with a limited variability range, as usual in the Amazon (21–33 °C). The average humidity is 90 % (59–100 %). The average wind speed is 1 m/s with peaks of 4 m/s. The Nanay river level grows from the month of November to the month of February, while it decreases from May to July. The period from March to May is the high level period of the Nanay River, whereas the period from August to October is the low level period. The meteorological data included in the implementation of the ABM are: the daily rainfall and the daily minimum and maximum temperature. All the daily meteorological data used in this paper were obtained from the records of the meteorological station number 843770 (SPQT) located close to the Iquitos airport, approximately 9500 m far from Padre Cocha.A. darlingi around 800 and 1500 m [The study area is covered by two distinct squared grids of different cell size. The first grid cover is called the mosquito grid cover, which is used to specify the mosquito agents positions. When mosquito agents are looking for blood meals or aquatic habitats, during night hours, they move every simulation time step from one mosquito grid pixel to another adjacent one. The mosquito grid cell size is calibrated to obtain flight ranges that are consistent with the majority of fields observation that report flight ranges for d 1500 m –35. PeriThe hydrological submodule implements an algorithm that reproduces in a simple way the floodings generated by the seasonal rise and fall of the Nanay River level in the area around Padre Cocha. The algorithm of the hydrological module converts a Nanay river level into a corresponding water cover. The input data of the hydrological submodule are: the monthly series of the Nanay River levels during the study period , two higThe mechanism underlying the hydrological submodule is simple: every 24 h during the simulation, the recorded value of the Nanay River level is read from the corresponding time series. Then the pixels that are covered by water in the high Nanay River water cover image and that have an elevation below the recorded Nanay River level are marked as covered by water.A. darlingi laboratory colonies reported a ratio of 6.6 emergent adults per oviposition. Although the laboratory conditions could be really different respect to the natural environment this value is adopted for the simulations. To include in the model the aquatic habitats carrying capacity [During the simulation, every geographical grid cover pixel covered by water is considered as suitable as breeding site with the exception of the central part of rivers where the water flow would flush out eggs and larvae. Mosquito agents are generated from aquatics breeding sites where other mosquito agents have previously laid eggs. The number of emergent mosquito per oviposition is determined by the model parameter: “Number of mosquito agents generated per oviposition”. This number depends on several factors like the mosquito species and the biophysical characteristics of the aquatic habitats. A recent study  conductecapacity , a maximA. darlingi during the periods corresponding to the low Nanay river level fall almost to zero. This occurrence may be due, among other things, to a minor suitability as aquatic habitats of permanent water covers than flooded areas. To reproduce this experimental fact in the model all the permanent water bodies generate a number of adult mosquito agents that is decreased respect to the number produced in the flooded areas by a factor whose value is specified by the state variable: “Reduction factor of the number of mosquitoes generated per unit of breeding area per unit of time in permanent water covers”.Several studies –40 reporA. darlingi shows high anthropophilic and endophagous behaviour [A. darlingi has been observed to be the almost exclusive malaria diffusion vector [A. darlingi ecology, ethology and biology. Although other species of the genus Anopheles observed in Loreto are competent malaria vectors, the minor relative importance of these species during the study period in determining the process of malaria diffusion and the similarities with the A. darlingi species assure that representing all the mosquito agents in the ABM as A. darlingi, is a quite good representation of the individual-based malaria vector dynamics in the Amazon. The values of all the parameters presented in the entomological module are showed in Table The ehaviour . In the n vector , especian vector  and whenn vector . For thiA. darlingi, a study of releases and recaptures of A. darlingi mosquitoes conducted in Rôndonia, Brazil [As noted, only the adult stage of mosquitoes is represented explicitly in the model and all the mosquito agents are females. In Fig. , Brazil  showed tCulicidae family can shows long range responses to nonspecific olfactory substances like the carbon dioxide produced by animals respiration. Moreover mosquitoes showed to be responsive to long-range stimuli of olfactory host-specific substances. Different compounds from human body have been identified as specifically attractive for mosquitoes. Furthermore mosquitoes show vision of poor resolution but of high sensitivity also in night-time that enables them to visually differentiate open spaces from closed dark spaces like forests also from distances of 15–20 m. It is still unclear if mosquitoes can show cognitive abilities such as learning the location of the visited hosts, of resting and breeding site [w if it contains breeding sites or human households, and (1 − w) in all the other cases .After mating, the mosquito agent immediately starts to search a human agent to have a blood meal (blood-seeking movement mode). If the mosquito agent succeeds in having a blood meal, the agent enters in the breeding habitat-seeking movement mode to find an aquatic habitat to lay eggs. It is known  that theing site . For thiing site . In bothA. darlingi mosquitoes conducted in Belize in a human altered rainforest environment [The influence of the wind over the mosquito host seeking and breeding site seeking movements is not included in the model. Despite the fact that for some mosquitoes species it was observed that a wind of 0.83 m/s may reduce the mosquito host-seeking flights , in a stironment , it was A. darlingi shows a nocturnal biting behaviour and two not pronounced biting peaks around dusk and dawn [In the northern Peruvian Amazon, and dawn . Therefoand dawn .Once the blood feeding process is complete, the ingested blood catalyzes the process of internal eggs development in the female mosquito . The gonThe length of the mosquito aquatic development stage is in general a temperature dependent process. Nevertheless here this time is considered as constant within a temperatures range typical of the Amazon . This deps of adult mosquitoes depends on many factors including the temperature. The classical relationship linking ps with the temperature that is reported by Craig [The daily survival probability by Craig  is descrT is the daily average temperature. As observed by Monterio de Barros et al. [A. darlingi daily survival probability can decrease during rainy days. For this reason in the model it is included a parameter called “survival probability factor during a rainy day” that sets the reduction of the survival probability during rainy days. A day is defined as a “rainy day” if the rainfall registered in this day is above a threshold specified by the model parameter “minimum rain of a rainy day”.s et al.  the A. dPlasmodium. The Plasmodium always has two hosts in its development cycle: a vector and a vertebrate host. In the case of Plasmodium species that cause malaria, the vector is a mosquito of the genus Anopheles and the vertebrate host could be a human as well as other mammal species like some monkeys. In the study area and in the Loreto Department, two different Plasmodium species are observed [P. falciparum and P. vivax. Each species of Plasmodium give rise to different transmission pattern and different infection dynamics [Malaria is caused by a parasitic protozoan of the genus observed : P. falcdynamics . The valPlasmodium and is determined by the length of the sporogonic cycle. The sporogonic cycle or duration of the sporogony (DS) is the time required from the moment of the mosquito infection, to complete the sporozoite maturation in the salivary glands of the vector. This period depends on the Plasmodium species and also on the temperature:The extrinsic incubation period is the only epidemiological feature in the model that originates from the interaction between mosquitoes and Tavg is the daily average temperature, Tmin is the minimum temperature required for the development of the sporozoites and DD are the parasite specific number of degree days needed to the complete the DS. Tmin and DD depend on the Plasmodium type [ium type .Plasmodium parameters describe the progression of the malaria infection in human individuals. The human agent infection dynamics is more complex than the in case of the mosquito agent because human agents receive anti-malarial treatments and can recover from malaria. The Plasmodium agent development stages when interacting with human agents is showed in Fig. The human related Plasmodium agent starts its development process. The first development step, after the end of the intrinsic incubation period, is the transition from asymptomatic to symptomatic. In the real world this transition corresponds to the moment when the infected individuals go to the village health post to receive the treatment against malaria and the new malaria case is registered. Therefore, in the model when a human agent enters in the symptomatic stage the number of simulated malaria cases is upgraded. When the intrinsic incubation ends, the human agent is tagged as symptomatic. After the infection, when the “gametocytaemia time” is passed, the Plasmodium agent starts the gametocytaemia. Corresponding with the gametocytaemia onset the human agent became infectious and can transmit the infection to a mosquito agent. The parameter: “human infectious period” sets the length of parasitaemia after the beginning of treatment.When a human is infected the P. falciparum and 12–17 days for P. vivax [Plasmodium cycle, the appearance of gametocytes depends on the first wave of asexual parasites. The time necessary for gametocytaemia onset varies considerably among Plasmodium species. In the case of P. falciparum the releasing of mature gametocytes takes 8-10 days after which the gametocytes become infectious to mosquitoes in 2–3 days [P. falciparum. The production of P. vivax gametocytes starts with the first generation of merozoites and therefore gametocytaemia may occur within 1–3 days after the first asexual parasites are observed in the blood [The World Health Organization reports that the intrinsic incubation period could be 7 days or longer . The estP. vivax , 57. The2–3 days . For thahe blood , 60, thiP. vivax gametocytes are susceptible to most commonly used anti-malarial treatments with an approximate circulation time of 1 day after treatment and they disappear with asexual parasite clearance [P. vivax. On the other hand, P. falciparum gametocytes have been found to circulate for up to 55 days after treatment unless primaquine is used, which reduces this time to approximately 6 days [P. falciparum parameter “human infectious period if treated” is 300 h which was based on the treatment regime used for Padre Cocha during the study period which included primaquine and sulfadoxine/pyrimethamine that eliminate parasitaemia in 7–14 days [Considering treatment, learance , 61. Thiy 6 days . The ave–14 days .P. vivax infections present themselves in cycles and recurrent infections are common [It must be considered that due to hypnozoite reservoirs in the liver, e common . Both rie common . Even thPlasmodium spp. from humans to A. darlingi mosquitoes has been determined in few studies, considering different factors such as asymptomaticity, parasite density and gametocytaemia. Bharti et al. [P. vivax to A. darlingi. In the study presented by Alves et al. [A. darlingi mosquito population. The same study found 22 % of symptomatic patients being able to successfully infect A. darlingi mosquitoes. In this model it is used a value of 0.4 for the transmission efficiency from symptomatic acute patients to mosquitoes for both P. falciparum and P. vivax. Given that asymptomatic patients are not as efficient transmitters and that their values for transmission efficiency are significantly lower, in this model the transmission efficiency from asymptomatic human agents to mosquitoes is set to 0.1 for both P. falciparum and P. vivax.Transmission efficiency of i et al.  found a s et al. , althougA. darlingi mosquito has nocturnal biting habits therefore the representation of daily human activities is not included in the model and the human agents are located in their houses and do not move during the simulation. In the study period the human population of Padre Cocha have oscillated between 1396 and 1405 inhabitants [Humans are represented in the model as individual agents. The abitants . The humabitants . The valThe human agent behaviour is designed to reproduce the changes in the adherence to methods of protection against mosquito bites. In what follows, any element that obstacles the mosquitoes in biting humans is considered as a protection method against mosquitoes bites . Several studies in Africa and in the Amazon and in other malaria endemic areas , 67 demoThe way human agents change their protection against mosquito bites state is represented as a flow chart in Fig. Pf is equal to 0 every attempt of bite will fail. At the end of the protection period when Pf is 1 every bite attempt succeeds. The reduction of the value of the variable Pf is introduced in the model to represent the diminution of the adherence to protection methods as well as the reduction in time of the effectiveness of the prevention method itself . The last possible action included in the human agents behaviour is the following: when the simulated malaria incidence falls below the value specified by the variable: “low incidence threshold” the human agent switches to a state of no protection against mosquito bites.After the period of total protection the level of protection against mosquito bites is linearly decreased and the period of partial protection starts. This period of partial protection lasts until the end of the protection period. At the beginning of the partial protection period when The model does not consider explicitly the dynamics of acquired immunity against malaria. Only a fixed portion of human agents is considered as immune, asymptomatic and constantly infectious. The study of Roper et al. in Padre Cocha during 1998 indicated that only 2 % of the asymptomatic population was positive for malaria ; neverthPlasmodium, the agent is considered as no susceptible to the infection of the other species of Plasmodium of the model.As mentioned by Roper et al.  no superP. vivax and P. falciparum incidences give rise to a simulated curve that, like the observed one, is almost zero during the months of August and September during the Nanay river low level season. The same simulated curve shows pronounced peaks corresponding to the Nanay river high level seasons from the month of March to the month of June.The model output resulting from the calibration process is presented in this section. In Fig. P. vivax and P. falciparum and the monthly incidence curves cannot be validated separately for P. vivax and P. falciparum malaria. The only available desegregated data [P. vivax and P. falciparum that are showed in Table Unfortunately, it is not possible to have access to the desegregated counts of the observed malaria monthly incidence for ted data  are the To show how the model is sensible to the interactions between human individuals and the environment where they live, a modified version of the model is produced where the adherence level to methods of prevention against mosquito bites is maintained constant. In this new model parametrization the seasonal changes of the adherence to mosquito bites preventions methods are not included and the fraction of protected human agents is maintained equals to 0.46. As it is showed in Fig. P. vivax and P. falciparum. The relative risk of these clusters is defined as the number of cases in a windows centered over a household observed during the simulation, divided by the number of expected cases in the same window. The range of variation of the relative risk is quite high, fluctuating from a maximum of 5.6 to a minimum of 0.01. For both P. vivax and P. falciparum clusters of high relative risk are observed for the households located closer to the permanent and seasonal mosquitoes breeding sites. In the central part of the village, far from water bodies there are clusters of low risk. The ABM simulation evidences also that isolated houses like those located on the northeastern and northwestern part of the village could be subjected to higher risk of malaria. In the case of P. falciparum it is possible to observe the presence of high relative risk clusters close to the floodable areas in the southeastern side of the village not observed for P. vivax. The significant spatial fluctuations caused by the households and larval habitats heterogeneous spatial distribution evidenced by the simulation are in good agreement with the results obtained from the same spatial analysis carried out on experimental data by Bautista et al. [As can be seen in Fig. a et al.  whose stA closer view of relative positions of households, malaria cases and breeding sites is showed in Fig. A. darlingi: areas associated with low level of shading resulting from deforestation, areas with large water bodies and areas close to human population [A. darlingi in Puerto Almendra, a village 18 km far from Padre Cocha, located in a riverine environment very similar to Padre Cocha, resulted very high if measured inside the village, while the same density fell almost to zero if measured 300 m far from the village in a unaltered forested site. These facts may suggest that if the unaltered total cover of the original forested habitat is restored in critical areas around a village as a kind of LSM habitat manipulation, the resulting shading effect would decrease the presence of A. darlingi and the malaria transmission. Another habitat alteration strategy could be the construction of barriers to prevent the water of the river to inundate the areas close to the village. In any case the result of the LSM would be the elimination of mosquito breeding sites around the village.The breeding sites management or larval source management (LSM) is an approach aimed at reducing the number of adult mosquito individuals emerging from breeding sites. The LSM can be implemented following various strategies, for example by manipulating the habitats eliminating standing water. A second strategy is the habitat alteration adding chemicals to water in order to kill or to prevent the development of the larvae . Obviouspulation , 41. Morpulation  found thb and Rb. The first radius is fixed in every scenario simulation and is equal to 20 m. The second buffer radius is greater than rb and changes in every test scenario. All the geographical grid cover pixels that are distant more than rb and less than Rb from a house belong to the buffer area and the pixels belongings to the buffer area are considered as not suitable as breeding sites. Six independent simulations were then carried out varying the value of Rb from 50 to 300 m in order to observe the effects of larval habitats elimination on the malaria incidence.The calibrated version of the ABM was used to simulate the effect of the elimination of mosquito breeding sites around the village of Padre Cocha. To carry out this test, several version of the model were built creating a sequence of “what if” scenarios. In these test simulations a buffer area is created around every house of the simulation. The buffer area is delimited by two radius rb. For Rb values above 200 m the malaria incidence fall almost to zero while for Rb = 150 m the incidence show a decreasing of the 87 %. This sharp effect is due to the fact that the mosquito agents have to increase the length of the blood-seeking and the breeding site-seeking times because with the increase of Rb the breeding sites are moving progressively further from the houses. This generates a gonotrophic cycle increase leading to a point where the average length of two gonotrophic cycles is greater than the average length of a mosquito agent life and the malaria transmission is blocked.Figure A. darlingi subadult development stage would imply the use of an extended set of unknown parameters describing the aquatic habitat in terms of mosquito eggs, larvae, and pupae predation, death rates, biomasses, number of eggs per oviposition and habitats carrying capacity. In the presented model mosquitoes breeding sites are only characterized as areas where the mosquito agents lay eggs and from where adult mosquitoes emerge in number proportional to the ovipositions. Other aspects of mosquitoes life cycle are not included: mosquito agents are strictly anthropophilic and the possibility of blood meals from animals is not included. Also some aspects describing the malaria transmission process like the transmission efficiency from mosquito to human are no included in the model because the value determination for this parameter is really problematic. For that reason in the model, the malaria transmission efficiency from mosquitoes to symptomatic humans is considered equal to 1 although in the real world this efficiency could be significantly less than 1 [The ABM presented in this paper reproduces the observed patterns of local scale malaria transmission dynamics in a small riverine village in the Northern Peruvian Amazon. As usual in agent-based modelling, a bottom-up strategy was followed: individual scale elements (human and mosquito agents) were assembled together with a macro scale environment description to create a model where macroscopic patterns emerge as a collective behaviour. On this regard the model offers an explicit representation of interactions between two populations of humans and mosquitoes in the context of a changing environment. The model was calibrated against empirical data of malaria incidence and the resulting calibrated model generated outputs that are in agreement with observed data. Obviously the model is not able to reproduce perfectly the malaria incidence time series and the observed spatial heterogeneities. Many factors not represented explicitly in the model contribute to the malaria transmission dynamics in the real world system. For example the exact relationships among the mosquito biology, ecology and ethology and environmental and climatic factors is far from being understood and studied in full detail. Consequently those interactions are represented only approximately in the model. For example the aquatic development stage of the mosquito life cycle is not represented in full details as shown in other individual-based models of malaria transmission , 23, 72.s than 1 . Similars than 1 . More sps than 1  showed tA. gambiae in an ABM of a hypothetical village where human habitations and breeding sites were created at random over a squared 40 × 40 grid. In this work the elimination of aquatic habitats generated a slower malaria incidence decrease, respect to what presented here, giving a reduction of 94 % in malaria incidence when the breeding sites were eliminated in a range of 300 m from the houses. The same model gives a reduction of 86.8 % with a buffer radius of 200 m. Although the flight ranges of mosquitos agent are similar in the model presented here respect to the model of Gu and Novak, the different behaviour of malaria reduction with the increase of the buffer radius can be explained in term of the different gonotrophic cycle lengths used in the two models and also because in the model presented here the aquatic habitats are no uniformly distributed across the simulation landscape and are concentrated in the floodable areas in southeastern side of the village very close to the houses.The validated version of the model was used to build several “what if” scenarios to understand the effect of larval sources site management. This result can be considered as an example of how an ABM of local malaria transmission could be used as a tool to study malaria transmission and to build a malaria control planning system . A numbePossible future development of this study will be the design and the inclusion into the model of more policy-oriented scenarios in order to create a simulation tool that could be integrated into a malaria control scenario planning system for low incidence malaria areas. Such a simulation tool could be used to explore the effect of several local scale strategies to control or eliminate the malaria transmission like intra-household prevention, environment management prevention and effects of anti-malaria treatments.


Rainfall erosivity is the potential ability for rainfall to cause soil loss. The purpose of this study was to estimate the rainfall erosivity index for the Ghana Atomic Energy Commission site in order to compute the surface erosion rate. Monthly rainfall data, for the period 2003–2012 were used to compute annual rainfall erosivity indices for the site, using the Modified Fournier index. Values of the annual rainfall erosivity indices ranged from 73.5 mm for 2004 to 200.4 mm for the year 2003 with a mean annual erosivity index of 129.8 mm for the period. The Pearson’s Coefficient of Correlation was used to establish the relationship between annual rainfall and annual rainfall erosivity. This showed a high degree of positive relationship (r = 0.7) for the study area. The computed mean annual erosivity index revealed that the site is in the high erosion risk zone. Therefore, it is necessary to develop soil protection and management strategies to protect the soil from erosion. Rainfall is a key contributing factor to land degradation such as soil erosion. This is as a result of the ability of rainfall to dissolve, loosen or worn away soil by the force of raindrops, runoffs, and river flooding and deposit in other places  site is eroded is of much concern as some of the nuclear installations of the Commission are underground and requires the soil to be conserved. Ghana is implementing the Borehole Disposal Concept (BDC), a specially engineered borehole, 30–100 m deep with narrow diameter (0.26 m) designed to dispose disused radioactive sources of less than 110 mm in length and 15 mm in diameter. This concept was developed in South Africa under the International Atomic Energy Agency’s (IAEA) AFRA project for the disposal of disused sealed radioactive sources (DSRS) in member states with relatively small DSRS inventories.To perform the Post Closure Safety Assessment on the proposed Borehole Disposal Facility (BDF) for Ghana, one of the key parameters that needs to be investigated at the proposed site is the surface erosion rate. This parameter will enable us ascertain the duration for the closure zone  of the BDF to be eroded for the disposed waste to be uncovered. To be able to compute the surface erosion rate, the rainfall erosivity index for the site is prerequisite hence the need to compute this parameter.Rainfall erosivity is a function of its amount, duration, drop size and drop size distribution, terminal velocity, intensity and kinetic energy. The significance of rainfall erosivity in the assessment of soil erosion risks stems from the fact that, unlike other natural factors that affect soil erosion, the erosive capacity of rainfall is not subject to human modification  and its revised version, RUSLE  and P: the annual rainfall amount (mm), Lujan and Gabriels  through the adoption of the MFI is presented in Fig. –2012 thrThe calculated Pearson’s correlation coefficient r value of 0.7 (at 0.01 level of significance) showed a positive degree of relationship between the amount of annual rainfall and the corresponding rainfall erosivity index Fig. .Fig. 4ReYearly variation of the erosivity index shows an intermittent trend as depicted in Table


Possible uncertainties caused by changes of the thyroid position relative to detector were studied in a series of measurements. The research has shown that the dispersion of the results can reach up even to the level of 50 %.The appropriate determination of the  The whole body spectrometry is a well known technique that enables to get information about activity concentration and distribution of radionuclides in measurement subject. The most important aspect of activity determination when measuring human body is not to underestimate uncertainties connected with individual features  and the position of each organ in human body –3. The to 25 cm3 .The series of the measurements was performed at IFJ PAN using the Whole Body Spectrometer (WBS) with 2 HPGe detectors . One of them is pointing at patient’s thyroid (X) and the other is located over abdomen (Y). The distance between centers of their windows is 52 cm. The main part is shielding, made of 18 t of XIX century steel, free from Co-60 contamination [3). Construction of the holder makes it possible to move the phantom in three directions   point, where: i = 1, 2, 3…274.The displacement of the phantom along x, y, z axis resulted in considerable changes of efficiency which reached up to the level of about 50 % for X and 30 % for Y detector. The lower than anticipated value for Y detector is due to the fact that the Y detector is located further and it is less sensitive to the influences of the small displacement of the thyroid.The research allowed to determine the area in WBS at IFJ PAN which is predestined for thyroid measurements characterized by relatively small uncertainties dependent of distance changes.131I in human body. The higher results for Y detector do not have any physical meanings besides the sole information, that 131I is observed somewhere else than in thyroid.The two detectors system which was calibrated for thyroid gland geometry has the advantage of giving more information about distribution of The results of the presented studies confirmed that the uncertainties dependent of the position of the thyroid during the measurements are not negligible. The described series of the measurements allowed us to find the optimal area for the thyroid position. In this space small shifts of this organ result in the smallest observed changes of relative differences of efficiency.