General practitioners (GPs) constitute a vital part of a strong primary health care system. We need further knowledge concerning factors that may affect the patients’ experiences in their meetings with the GPs. We investigated to what degree organizational factors and GP characteristics are associated with patients’ communicative experiences in a consultation.We used data from the Norwegian part of the international, multi-center study Quality and Costs of Primary Care in Europe (QUALICOPC). We included 198 Norwegian GPs and 1529 patients. The patients completed a survey concerning experiences in a consultation with a GP on the inclusion day. The GPs completed a survey regarding organizational aspects of their own practice. Main outcome measures were seven statements concerning how the patients experienced the communication with the GP during the consultation. A generalized estimating equation logistic regression model was used to identify variations in patient experiences associated with characteristics of the GPs and their practices.The patients reported overall positive experiences with their GP consultations. Patients who consulted a GP with a short patient list were less likely than patients who consulted a GP with a medium sized list to regard the GP as polite (Odds Ratio (OR) 0.2; 95 % CI 0.1–0.7), to report that the GP asked questions about their health problems  or that the GP used sufficient time . Patients who consulted a GP with a long patient list compared to patients who consulted a GP with a medium sized list were less likely to feel that they could cope better after the GP visit  and more likely to feel that the GP hardly looked at them while talking . No associations with patient experiences were found with the average duration of the consultations, whether the GP worked in a fee-for-service model or whether the GP was the patient’s regular doctor.Norwegian patients report predominantly positive experiences when consulting a GP. Positive communication experiences are most likely to be reported when the GP has a medium sized patient list. Structure , process , and outcome  [Primary health care is increasingly acknowledged as the linchpin of a strong health care system , 2. Most health) . PatientPatient satisfaction has been commonly used as an indicator of the quality of primary health care systems and individual health suppliers in different contexts , 5. The The main aspects of consultations with a GP, as judged by patients, have been reported to be the interaction with the doctor and the outcome of the consultation . In addiThe frame-work of primary care varies throughout Europe. In Norway most GPs are self-employed, and as such have substantial freedom in terms of how they organize their practices , 12. TheThe QUALICOPC  study is a multi-centre study that comprises 34 countries . A set oThe study is based on data from the Norwegian part of the QUALICOPC study. Data collection took place from November 2012 to April 2013. The four Norwegian General Practice Research Units at the Universities of Oslo, Trondheim and Tromsø and the research institute Uni Research Health in Bergen were all involved in recruiting doctors and patients to the study, thus ensuring that we received information from the entire country. GPs were contacted via formal and informal GP networks, and those who were willing to participate were sent a survey set or received a visit from a fieldworker. The Norwegian material consists of information from 198 GPs and 1704 patients. In total, 1529 patient completed the experience form and 175 completed the values form.The present study uses data from the patient experiences and the GP questionnaires. Table p < 0.05.Due to the hierarchical structure of the data, we used a generalized estimating equation (GEE) logistic regression model. This modelling technique helped to account for the variability in patients’ experiences between the GPs and to establish any variation at the GP level. The significance level was set to All analyses were performed using SPSS statistics 22.Tables Patients’ reports from their consultation with the GP were generally positive. A great majority of the patients reported that the GP was polite (97.9 %), listened carefully 97.1 %) and took sufficient time (91.1 %) Table . Most pa % and toTable Patients visiting a GP in a rural area were more likely to answer yes to the statement “I couldn’t really understand what the doctor was trying to explain”  compared to patients visiting doctors in an urban area.When analysing the impact of the doctors’ age, the middle age group (36–59 years) was defined as reference. Patients visiting a GP aged 60 years or more were less likely to answer yes to the statement “The doctor asked questions about my health problem” . This was also true when compared to patients visiting GPs in the youngest age group . This was the only significant association found with the GPs’ age.When analysing the impact of the patients’ age, we also defined the middle age group (30–65 years) as the reference. Patients less than 30 years old were more likely to answer yes to whether the doctor asked questions about their health problems . Patients above 65 years were more likely than the middle aged patients to answer yes to the statements “The doctor hardly looked at me when we talked” , and “After this visit, I can cope better with my health problem/illness” . When using the youngest age group as reference, additional differences were identified: Both the middle age group  and the oldest age group  were less likely to state that the GP asked additional questions. The oldest patients were more likely to feel that they could cope better after the visit to the GP than the youngest patients . The oldest age group was more likely to answer yes to the statement “I couldn’t really understand what the doctor was trying to explain”  compared to the middle age group, but no difference was found when compared to the youngest age group.We found no associations between the patients’ experiences and the GPs’ form of employment, the average duration of consultation estimated by the GPs or whether the GP was the patient’s regular doctor or not.The patients in our material reported an overall positive experience with their GP consultations. The patients’ experiences were to a certain extent influenced by the size of the GP’s patient list, the geographical location of the practice and the GP’s age. Among these effects, the list size stands out as the most influential, and both short and long patient lists were associated with a more negative patient experience. We also found that the patients’ age was of significance as to how they perceived their visit to the GP. The older patients were more likely to experience that the doctor did not look at them while talking, and they found it more difficult to understand what the GP tried to explain. Nevertheless, they were also more likely to feel that they could cope better with their health problems after the visit to the GP.We found an association between the size of the GPs patient lists and the patients’ experiences. Intuitively, and based on previous reports –20, one On the other hand, patients who attended GPs with the largest patient lists were more likely to report that the doctor hardly looked at them while talking and less likely to feel that they could cope better with their health problems after the visit to the GP. It is possible that the busy doctors with the largest patient lists devote less time to making sure that their intended message has been received by the patients, and with a higher patient turnover there may be less awareness towards the patients’ need to ask clarifying questions.A Dutch study concluded that the optimum practice size with regard to the physicians’ workload was found in the largest practices, but they did not investigate the effects on patients’ experiences . In a rePatients who consulted a GP in a rural setting were more likely to report that they had problems understanding what the GP was trying to explain. This could be due to language problems, as GPs with an immigrant background more often than other GPs work in rural areas of Norway .A recent paper based on the international results from the QUALICOPC study investigated the patients’ evaluation of the importance of different aspects of the contact with the GP . The NorThe recruitment procedure for the participating GPs was suboptimal in terms of obtaining a random selection. The GP population in the study is a convenience sample recruited through formal and informal networks of the four participating research units, and is therefore not necessarily a fully representative sample of Norwegian GPs. However, the GPs were recruited from various geographical regions throughout the country. Some of the GPs have university affiliations and may therefore be more positive than most GPs towards participations in research projects. In 2013, 38.6 % of Norwegian GPs were female , in our As our data origins from a larger, international study, it was not possible to fully customize the questions to Norwegian conditions or to the specific needs of the present national study. Information about how many days per week the GPs work in their practices and more detailed information about the geographical location would have been of value to our study.The strength of our study lies in the size of the material and the possibility to link information from the patients with detailed information from the actual GP they attended. The data were obtained from all over the country and are representative of the Norwegian GP population. The patients answered the questions in the GPs’ waiting room, thus minimizing the potential for recall bias. Since the organisation of Norwegian general practice is rather diverse, we believe that our findings are of relevance even when evaluating primary care systems in other countries.Norwegian patients report predominantly positive experiences when visiting a general practitioner.Both short and long patient lists were associated with various negative patient experiences in the consultation with the GP. A rural location of the GP practice was negatively associated with the communicative experience of the patients.Our study suggests that from the patients’ point of view, it is preferable for GPs to have a medium size patient list to allow for a positive communicative experience in the consultation.


Honey bees have the ability to detect the Earth’s magnetic field, and the suspected magnetoreceptors are the iron granules in the abdomens of the bees. To identify the sensing route of honey bee magnetoreception, we conducted a classical conditioning experiment in which the responses of the proboscis extension reflex (PER) were monitored. Honey bees were successfully trained to associate the magnetic stimulus with a sucrose reward after two days of training. When the neural connection of the ventral nerve cord (VNC) between the abdomen and the thorax was cut, the honey bees no longer associated the magnetic stimulus with the sucrose reward but still responded to an olfactory PER task. The neural responses elicited in response to the change of magnetic field were also recorded at the VNC. Our results suggest that the honey bee is a new model animal for the investigation of magnetite-based magnetoreception. Honey bees are homing social insects whose workers collect food from a distance of up to 12 km away from the hive23468111214151617181920Drosophila melanogaster. These flies have been trained to respond to the magnetic field under full spectrum light (~300–700 nm), but if the UV-A/blue part of the spectrum (<420 nm) is blocked, the flies no longer respond to the magnetic field3O4 located in their bodies33333739404143There are two models of the magnetoreception system in terrestrial animals–chemical magnetoreception22262925pectrum <0 nm is bIron granule-containing cells are present in the abdomen of the honey bee and these have had been suggested to serve as a magnetoreceptor214546474849142145464846215152p = 0.017 < 0.5) , whereas there were only 1.40 ± 0.18 turns made before the stimulus (0:00 to 1:30) and 1.27 ± 0.19 during the after stimulus period (3:00 to 4:30). The data on body turns in response to the magnetic azimuth were analysed with a Kruskal-Wallis ANOVA, and the difference appeared to be significant  . This rest training day, but they responded much better on the 2nd day. On the 1st training day, the average conditioned stimulus (CS) PER response was 2.4 ± 0.8 times out of 20 trials (mean ± SEM); on the 2nd day, the average PER response increased significantly to 7.9 ± 0.7 (mean ± SEM)  (th training (the 17th training on the 2nd day). The successfully trained bees would extend their probosces during the magnetic stimulus. The data for the individuals that were dead on the 2nd training day (n = 4) and had never responded to the magnetic stimulus during the two days training (n = 12) were not included in this result.In the PER experiment, each of the tested honey bees underwent 20 training trials per day. The bees seldom responded to the stimulus on the 1 n = 10) . The sucAfter the PER training, we cut the VNCs of the bees that had already learnt the association between the magnetic stimuli and PER (defined as the bee responding to the stimulus twice in a row). After VNC cutting, the bees no longer responded to the lateral stimulus (n = 10). As a control, the bees had also been trained to exhibit PERs to an odour stimulus, and the post-operative bees were still able to do this after VNC cutting. The bees remained 100% responsive to the odour stimulus following the first training trial after cutting the VNC, indicating that cutting the VNC at the first training trial had no influence on the odour PER. Clearly, the bees receive magnetic information through something in their abdomen, most probably the iron granules, and these signals are transmitted through the VNC.The signals that indicated response to the magnetic pulse were recorded at the VNC of the ‘neck’ of each bee. The field intensity was 65 μT, and the field direction was vertical to the geomagnetic field. The responses matched the stimulus perfectly . BecauseThe magnetoreception of the honey bee has been studied for decades. However, the source of the magnetic signals is still unknown. In this research, we explored whether the signals come from the abdomen. Our first experiment showed that bees can respond to changes in the magnetic azimuth in a totally dark environment. Cryptochromes, which are considered to be the magnetoreceptor in chemical magnetoreception systems, cannot function without being excited by UV-A/blue light (<420 nm)In previous magnetoreception studies, insects have been trained in discrimination experiments16171854During the PER training, we also noticed that there are several individuals that never responded to the magnetic stimulus. This finding may be a result of the method used to collect the foragers. The suspected magnetoreceptor of the honey bees, the iron granules, accumulate as bees age4748Once we confirmed that the bees could sense the magnetic field, we tried to identify the source of the signal. Previous studies have mainly focused on the location14214546484621The electrophysiological responses recorded from the VNC showed that there were two types of responses, the ON type  and the 38Although we have confirmed that the bees can sense a magnetic field from the abdomen, we do not have enough evidence to rule out the participation of cryptochromes in honey bee magnetoreception. The cryptochromes, which have been confirmed to be the magnetoreceptor in most other insects that can sense a magnetic field, such as the fruit flyOnly honey bee foragers were used in this research, and this experiment was conducted in a dark room. The bees were captured in the afternoon and maintained in a plastic cup  with water and food. The cups with the bees were placed in a refrigerator (~4 °C) and the cold-anaesthetised bees were transferred individually into Petri dishes , which were placed on a wooden board in the coil at 20:00. On each experimental day, 18 bees were tested simultaneously, and each dish was surrounded by a strip of paper to prevent the bees from seeing each other.−8 Ω·m) were wound into four coils that consisted of 26, 11, 11 and 26 turns, sequentially. The side length of each square coil was one metre, and the spacing of the neighbouring coils was consequently 37.74, 25.62 and 37.74 cm. The four coils were serially connected to a DC power supply to generate a uniform magnetic field at the central area of the coils. The coil was placed vertical to the geomagnetic field (approximately 40 μT) and generated a 65 μT field, which induced the horizontal component to rotate 60° clockwise.The magnetic stimulus was generated by square coils. The square coils were implemented using a scheme similar to the Merritt four coil systemThe experiment took place between 0:00 and 4:30, and images of the bee behaviour were recorded every five minutes by an infrared camera, which was placed 50 cm above the wooden board. Except for the lens, the camera was wrapped in aluminium foil grounded with wire to minimise the potential influence of the magnetic field. The square coils were turned on/off to change the magnetic azimuth every 5 minutes during the stimulus period (from 1:30 to 3:00). The data of the ‘before stimulus’ (from 0:00 to 1:30) and ‘after stimulus’ (from 3:00 to 4:30) served as the control group. The images were visually checked on the computer, and we counted the body turns when the body axis slewed more than 10°.−6 H/m, χm = 700), we constructed a semicircular magneto core with an air gap. A thin enamelled wire coil  consisting of 1200 turns was wound onto the magneto core to induce a magnetic field in the air. The coil wire received an electric current whose amplitude and frequency were regulated by an external controller, which allowed the direction of the magnetic field to be modulated or the core to be demagnetised.To examine the magnetic sensing capability of the honey bee, a magnetic field generator was built to deliver short pulses of magnetic fields to the body of the honey bee. Using ferritic stainless steel with low magnetic susceptibility , and the stimulus was 5 Hz from an alternating field.The bees were trained to have a PER. The CS  was a magnetic stimulus, and the unconditioned stimulus (US) was a 50% sucrose reward. Before training, each honey bee was first offered sucrose to make sure that she had a normal PER response to the US. To confirm the transmission of the magnetic signals, microsurgery was used to cut the nerve connection between the iron granules in the abdomen and the brain. The successfully trained bees (those that had previously responded twice in a row to the magnetic stimulus) in PER training were used for the experiment. The surgical process was carried out as follows. (1) Bees were fixed on Styrofoam using pins that were not inserted into the honey bee’s body. (2) A small incision was made on the underside of the first abdominal sternum. The ventral nerve cord and a globe, known as the first abdominal ganglion, were visible. (3) The VNC was cut above the first abdominal ganglion to ensure that no signals from the abdomen could pass to the brain. (4) The wound was covered with petroleum jelly to reduce transpiration. After microsurgery, each bee was subjected to the magnetic stimulus again, and the response was recorded.To eliminate the possibility that it was the surgery that resulted in the bees being unable to have a PER, the odour PER was applied as a control. The odour PER training process was conducted as follows. (1) The odour stimulus was applied for 6 seconds as the CS. (2) The sucrose reward was given immediately after the CS. (3) Then, there was a 10 second rest to allow each bee to retract its proboscis. (4) The stimulus was then reapplied to test those bees that did not follow the CS. The successfully trained bees (those that responded twice in a row to the magnetic stimulus) had their VNCs cut as described above. After surgery, the bees were again subjected to the odour stimulus, and their responses were recorded.The magnetic field generator used in this experiment was the same as the one used to test the effects of the bee rest behaviour in response to magnetic azimuth changes. In this experiment, the glass microelectrodes were used to record the neural response. The microelectrode was made from a glass capillary tube , which was manufactured with a micropipette puller . The well-prepared microelectrode was sharp at the tip and tough enough to penetrate the nerve cord. A head stage was used to receive the signals from the electrode. The ‘probe+’ of the head stage was attached to a silver wire , which was coated with AgCl on the surface, and then the wire was placed in the microelectrode as the recording electrode. The ‘probe-’ and the ‘probe ground’ of the head stage were tied together and attached to another silver wire as an indifferent electrode. The electrical signals could then be amplified by an AC/DC Differential Amplifier , transmitted to the computer and recorded by the program DataWave SciWorks . The sampling rate was 5 kHz and we used a digital filter set as 70 Hz high pass. Finally, the response was drawn by using the program Origin .Only foragers were used in this experiment. The bees were fixed on the pipette by using the same method used in the PER training, and all legs were removed to reduce interference. We recorded the signals from the ventral nerve cord between the thorax and the brain, which we located after removing the membrane on the ‘neck’. The indifferent electrode was placed in the mesothorax. Each bee was placed parallel to the geomagnetic field, and the magnetic field generator was placed vertical to the geomagnetic field and generated a 65 μT field, which induced the horizontal component to rotate 60° clockwise.How to cite this article: Liang, C.-H. et al. Magnetic Sensing through the Abdomen of the Honey bee. Sci. Rep. 6, 23657; doi: 10.1038/srep23657 (2016).


Adherence to expert consensus guidelines on FMD measurement has been found to be of vital importance to obtain reproducible data. This article lists the literature data which was considered in the development of a tool to aid in the objective judgement of the extent to which published studies adhered to expert guidelines for FMD measurement. Application of this tool in a systematic review of FMD studies ( Specifications Table•The literature data provided here establishes an evidence base and a physiological background rationale for the individual components included in the Adherence Score, aiding in the improvement of the practical guidance and technical approaches to FMD measurement and analysis.•This “Adherence Score” which ranges between 0 (i.e. no adherence) and 10 (i.e. full adherence) can conceivably be employed to evaluate the perceived quality of studies reporting FMD data, with a higher outcome of this measure being strongly related to better reproducibility of the FMD data •This tool may prove useful additional information when pooling, contrasting and comparing different studies, e.g. for the purpose of meta-analyses or systematic reviews.1“Adherence Score” tool along with citations to the literature data which justify the inclusion of each factor in question.A tool to enable objective assessment of the level adherence to the FMD guidelines was developed. 2“Adherence Score” that any given study can be assigned ranges from 0 to 10 points depending on how many of the 19 different factors that are reported or referred to in the text of the paper in question.Based on previous expert-consensus guidelines


A value of about 60 fs has been found. Due to this “long” lifetime the line shape is much less structured than calculated with the reported lifetime.Crystal-GRID measurements have been performed with ZnS single crystals. For the first time, an asymmetric Crystal-GRID line shape could be observed. The preliminary data evaluation indicates that the reported lifetime of the 3221 keV level in  During the last decade the Gamma Ray Induced Doppler broadening (GRID) technique has been optimised at the Institut Laue-Langevin (ILL). It has been successfully applied to lifetime measurements. A description of the method can be found in Ref. .The use of single-crystalline samples for GRID experiments was proposed during the first GRID workshop in 1992 ,4,5 the In this paper a preliminary report on measurements with ZnS single crystals will be presented. These experiments aimed to observe for the first time a theoretically predicted asymmetry  of the Dγ-cascade. The emission of a first, primary photon γ1 entails a recoil of the still excited nucleus due to the conservation of momentum p:m is the mass and v0 the initial velocity of the recoiling nucleus, c the velocity of light. As the energy of the first photon is of the order of several MeV, the initial velocity v0 of the recoiling atom lies in between 10−5c and 2 × 10−4c, corresponding to an initial kinetic energy Ekin,0 of approximately 100 eV to 1000 eV. The direction of the initial recoil is arbitrary. The further motion of the recoiling nucleus is defined by the interatomic forces, i.e., by the interatomic potential in the solid.In a thermal neutron capture reaction the binding energy of the neutron is deposited in the nucleus and the deexcitation takes place via a t′ a second photon γ2 is emitted and observed by the spectrometer if emitted along the direction of observation. If the nucleus [velocity v(t)] has not yet come to rest, the γ energy is Doppler shifted byn the unit vector in the direction of observation. Due to the total number of Doppler shifted photons a Doppler broadened photon energy spectrum is obtained.At the time The motion of the recoiling atoms within a single crystal is highly anisotropic. For example, the slowing down in the direction of the nearest neighbour (“blocking”) is more efficient than in the direction between two nearest neighbours (“channeling”). Therefore, the isotropic distribution of velocities just after the recoil becomes anisotropic as soon as the interaction with nearest neighbours becomes non-negligible. In a powder target this anisotropy is averaged out by the arbitrary alignment of the micro-crystals. However, in the case of a single crystal this anisotropy exists macroscopically and leads to a fine structure in the Doppler broadened line shape. As the fine structure is caused by the interaction of the recoiling atom with its neighbours it represents a sensitive indicator for the interatomic potential.14 neutrons/cm2s). In general, three oriented crystals of size 17 mm × 20 mm × 2 mm are used for the measurements. Two high-resolution gamma spectrometers, GAMS 4 and GAMS 5, are placed on either side of the beam tube at a distance of 13 m and 17 m of the samples, respectively. Both operate in double flat crystal geometry, i.e. energy resolution is gained by successive Bragg reflection on two almost perfect single crystals.Crystal-GRID measurements can be performed at the high-flux neutron reactor of the Institut Laue-Langevin in Grenoble. The crystals to be investigated are placed in a distance of 55 cm from the reactor core in a tangential beam tube, where they are permanently irradiated by thermal neutrons (≈ 5 × 10γ cascade with a mostly primarily fed short living (5 fs to 40 fs) level. The primary feeding guarantees an almost monoenergetic recoil energy, the short lifetime the restriction to a few collision processes. Further, the coordination number of the material itself should be as low as possible. In this case the anisotropy of the recoil motion and therefore the fine structure in the Crystal-GRID line shape is strongly pronounced.Theoretically, Crystal-GRID studies can be performed with a large number of materials, however the sensitivity of the Doppler-broadened line shapes to the atomic interaction depends on a number of criteria. First of all, the material should contain an isotope, which has a simple γ-cascade with short lived levels, light nuclei would be preferential. However these isotopes do often have a very small neutron capture cross section. This limits currently the number of candidates for Crystal-GRID experiments to isotopes such as 36Cl, 49Ti, 56Fe, 59Ni, 52Cr, and 33S. Therefore improvements of the spectrometer efficiency are urgently needed. A first step will be done with GAMS 5. An efficiency improved by a factor of 100 would be needed, in order to be able to investigate alot of materials that are of great interest in solid state physics, for example, a number of important semiconductors.In an experiment a number of additional requirements have to be met: Currently, the intensity requirement is the most limiting. For that reason sufficiently big single crystals are needed. The typical size used up to now is three pieces 17 mm × 20 mm × 2 mm. As soon as GAMS 5 is operational in bent-crystal mode, thin single-crystalline films should also be usable. Further, the measured intensity depends on a number of quantities such as the capture cross section, the absolute intensity of the transition, and the response function of the spectrometer, which itself depends on the energy as well as the thickness and the material of the crystals used in the spectrometer. According to the requirement of a simple Because the crystal temperature can reach 1200 K in the reactor, the crystal structure needs to be stable up to this temperature region. Furthermore reactor safety requirements must be considered .Once these basic requirements are fulfilled, theoretical calculations can be performed (see Sec. 4). If a line shape is very structured or not, depends mainly on the lifetime and the crystal lattice. Short lifetimes and open structures lead to the most pronounced line shapes.−3c), electronic excitations are not taken into account. This allows consideration of the recoil motion within classical mechanics. The most exact computer simulation approach within classical mechanics are molecular dynamics (MD) calculations. In these calculations the motion of N atoms within a finite volume V is calculated assuming certain initial and boundary conditions and the knowledge of the atomic interaction of all N atoms. The trajectories of the particles can be calculated by simultaneously integrating Newton’s equations of motion of all N particles. In the case of recoil simulations for Crystal-GRID experiments the initial conditions are defined by the crystal structure of the targets, where all atoms move at an initial velocity following a Maxwell distribution corresponding to the temperature of the crystal. The simulation volume is a cubic cell, the size of which is adjusted such that the recoiling atoms do not reach the boundaries within the time of simulation. Periodic boundary conditions are used. Starting with an initial recoil, possible trajectories can be simulated. The method is exact within classical mechanics. Hence the result of MD simulations is as good as the interatomic potential. However, MD simulations are very time consuming. For our purpose only the interaction of the recoiling nucleus with all its neighbouring nuclei needs to be known. The interaction of two nuclei far away from the recoiling nucleus has no appreciable influence and can be neglected. This approximation is called “restricted molecular dynamics” (RMD) and is sufficient for Crystal-GRID simulations [An analytical calculation of theoretical line shapes is only possible for simple assumptions on the slowing down process. Crystal-GRID line shapes can not be deduced with sufficient accuracy in that way. We have to use computer simulations instead. As the recoil velocities of the atoms are much below typical electron velocities ≈ 7 × 10−c, electri(t) with velocities vi(t) have been simulated with an RMD program. For better statistics the symmetry operations of the appropriate point group can be applied to the trajectories. In order to compare simulation and experiment the set of trajectories needs to be transformed to a probability distribution of velocities or energies. In an actual measurement the direction of observation is fixed. As seen in v‖ = v·n of the velocity on the direction of observation.For ZnS 1400 trajectories n the velocity projection distribution P dv‖ dt can be deduced by counting the trajectories having a velocity projection vi(t)·n in the range v‖ … v‖ + dv‖ during the time interval t…t + dt. A normalisation of the distribution is not necessary, because the measurement does not yield absolute intensities. This distribution is independent of the lifetime of the nuclear state, because the trajectories have been calculated for a fixed period of time regardless of the second decay.For a given P(v‖) dv‖ of velocity projections v‖ at the time of the second γ decay can then be calculated for a given lifetime τ by multiplying the radioactive decay law:The distribution τ, where 99.3 % of the secondary photons have been emitted. Using The integral is calculated up to 5σEW, the so called “excess width”. The later can be determined experimentally. When folding This line shape would be measured with a spectrometer yielding a δ-like response function. In the case of an ideal double flat crystal spectrometer the instrumental response function can be calculated from diffraction theory. Due to small imperfections of the used spectrometer crystals an additional broadening has to be taken into account by folding the ideal instrument response function with a Gaussian of width ails see ).As can be seen, the measured Crystal-GRID line shapes are directly correlated to the slowing down process in the crystal. For a given crystal structure and alignment of the crystal, the calculated line shape depends only on the classical potential used in the RMD calculation and on the level lifetime. Therefore, by comparing simulation and measurement, the interatomic potential may be improved in the energy region of 10 eV to 1000 eV.Under normal conditions, Zinc sulfide (ZnS) has the zincblende structure  fs [During two measuring periods we examined the ZnS crystals with the 〈111〉 and 〈110〉 directions respectively oriented towards the spectrometer. The measurements used the 2380 keV transition in the tate see . Two two± 12) fs .The double crystal spectrometer was used with one crystal in first and the other in second reflection order. For each orientation of the crystal 35 scans have been measured. Every scan consisted of 90 data points, each of them being measured for 320 s. Thereby a peak intensity of about 40 counts per scan could be attained.The data evaluation is still in progress. Up to now we obtained two preliminary results. On the one hand, for the first time, the predicted asymmetry of the line shape in the 〈111〉 direction could be confirmed see . On the Due to the long lifetime the line shapes are much less structured than predicted by the computer simulations performed before the experiment with the reported lifetime. Thus, the information which can be gained for the interatomic potentials will be reduced.ab initio — calculations. These calculations allow to obtain the total energy of an arbitrary configuration of typically 64 atoms without requiring any information about classical interatomic potentials. By calculating the energy of a series of atomic configurations, an interatomic potential can be developed theoretically.Our second, purely theoretical approach to ZnS potentials consists of quantum mechanical — so called ab initio potential (see In a first step one of the S atoms within a simulation cell of 64 atoms was displaced along the 〈111〉 direction towards its nearest neighbour. For different distances the total energy has been calculated. The difference to the total energy of the ideal lattice gives a first approach to an tial see . Even thab initio potential. As can be seen in χ2 value of the fit, however, is higher, i.e., worse, than for the screened Coulomb potentials. This indicates that the ab initio potential does not well describe the slowing down in the crystal. This may be due to some crucial approximations within the ab initio calculations, e.g., with respect to the exchange energy, that have to be made. Further approaches will be made in order to improve the potential.RMD calculations have been performed with this deduced 33S is about 60 fs. This value is well above the previously reported value. Therefore the line shapes are less structured than predicted.Crystal-GRID measurements have been performed with ZnS single crystals. For the first time, the theoretically predicted asymmetric line shape could be verified experimentally. At the actual state of data evaluation it seems to be clear that the lifetime of the 3221 keV level in Due to the reduced information that can be extracted from the line shapes, a third ZnS measurement has been proposed. It should be performed in the 〈100〉 orientation. With the additional results it should be possible to validate interatomic potentials even though, due to the “long” lifetime, the transition is not optimal for Crystal-GRID studies.ab initio results do not yet yield sufficiently good results. Nevertheless the simultaneous experimental and theoretical approaches allow a direct comparison of the results, leading to an increased reliability of the obtained potentials.The first


The purpose of this paper is to analyse the development and the evolution of the fracture process zone during fracture and damage in quasi‐brittle materials. A model taking into account the material details at the mesoscale is used to describe the failure process at the scale of the heterogeneities. This model is used to compute histograms of the relative distances between damaged points. These numerical results are compared with experimental data, where the damage evolution is monitored using acoustic emissions. Histograms of the relative distances between damage events in the numerical calculations and acoustic events in the experiments exhibit good agreement. It is shown that the mesoscale model provides relevant information from the point of view of both global responses and the local failure process. © 2015 The Authors. International Journal for Numerical and Analytical Methods in Geomechanics published by John Wiley & Sons Ltd. At the tip of the macro‐crack and ahead lies the so‐called fracture process zone (FPZ), which is a region of the material undergoing distributed damage. The size of the FPZ in these heterogeneous materials is large enough to influence the mechanical behaviour of the structure significantly. The understanding of the evolution of the FPZ size in such heterogeneous materials is still an open issue in the community. It is commonly accepted that this FPZ size does not depend on the structural size but is rather controlled by the local heterogeneities in the material as well as by the geometry of the specimen and the stress state. Therefore, size effect, understood here as the dependence of the dimensionless nominal strength of a structure on its size, is observed . Disorder due to the heterogeneity of the matrix that contains small aggregates is still kept, however, in the form of a correlated random distribution of mechanical properties. The correlation length is independent from the fineness of the lattice and therefore provides results independent of lattice element size independent The large aggregate is elastic. The matrix material follows an isotropic – scalar – damage model.Each aggregate is surrounded by an interface of thickness equal to one lattice element length, which is endowed with a special constitutive relation. This interface is meant to represent the interfacial transition zone (ITZ) in concrete. Its constitutive model is similar to that of the matrix, with different constants because the ITZ is usually weaker than the matrix.The 2D plane‐stress lattice model proposed first by Grassl and Jirasek dmin is enforced. The lattice elements result then from a Delaunay triangulation  and one rotation (φ) as depicted in Figure ue=T, are linked to the displacement jumps in the local coordinate system of point C, uc=T, by the following relation:A is the element cross‐sectional area and I its second moment T associated with the displacement uc at point C areh is the distance between the two nodes of one lattice element. The stresses σ = T are related to the strains ϵ following the mechanical constitutive relation at the lattice level, here an isotropic damage model to be described further. The subscripts n and s refer to the normal and shear components of the strain and stress vector. The (secant) stiffness matrix K of the lattice element is defined as follows:D is the material stiffness matrix computed at point C.Point ω is the damage variable, De is the elastic stiffness and σ¯=σ¯n,σ¯s,σ¯φT is the effective stress. The elastic stiffnessE and γ, which control Young's modulus and Poisson's ratio of the equivalent continuum h = ℓ and e = 0, the stiffness matrix K reduces to the Bernoulli beam stiffness matrix The same isotropic damage model Eq.  is used ϵ0, c and q are model parameters.ω is derived by considering pure tension, where the softening curve under monotonically increasing tensile strain is chosen to be of the exponential type:wcn=ωhϵn is the crack opening and wf is the initial slope of the softening curve, which is related to the mesolevel fracture energy as Gf=ftwf. This stress–strain law can also be written, for pure traction, as a function of the damage variable asThe equivalent strain is then calculated from Eq. ft=Eϵ0), and thus, by using these two expressions of σn, Eqs. ω:ϵn has been replaced by κ, which is a history‐dependent variable determined by Eq. In pure tension, the nominal stress is limited by the tensile strength , a = 0.2D  and a = 0.5D . For a detailed presentation of the experiments, refer to Figure D, because the location of the fracture process zone initiating from the surface was indeterminate.The analyses were controlled by the crack mouth opening displacement (CMOD), which is the relative horizontal displacement of the points A and B shown in Figure D = 200 mm and a beam of type FN with D = 250 mm. These beams are denoted as UN200 and FN250, respectively. The beams HN200, FN125 and UN100 correspond to a ligament length of 100mm. Beams HN100, FN62.5 and UN50 have a ligament length of 50mm.Additional calculations on geometries that were not tested experimentally were performed in the present study in order to investigate beams of different sizes but with a different notch length, so that the ligament length is kept constant. This is motivated by the results obtained in b = 50 mm. The notch thickness was fixed equal to zero for consistence with the experimental procedure, where the notch was moulded using a thin metal plate of constant thickness. The load and support reactions were applied by means of 5‐mm‐wide metallic plates.Same as in the experiments, the out‐of‐plane thickness was kept constant for all sizes and all geometries at φmin=5 mm. Fine aggregates are not explicitly described. They are included in the matrix, which is an equivalent homogeneous material made of cement paste and fine aggregates. Disorder due to the heterogeneity of the matrix is considered in the form of a correlated random distribution of mechanical properties. The correlation length is equal to 1mm. Details may be found in q,c and Gf, are taken from In order to limit the computation time, the nonlinear mesoscale model is used in the middle part of each beam centred at mid‐span, where damage is expected, as shown in Figure the distance between damage events. The histogram of these relative distances should exhibit correlations because of the distribution of strain (and therefore the loading conditions) within the lattice and also correlations induced by interactions during failure. Such correlations have been investigated by Delaplace and co‐workers Because we are basically repeating the calculations reported in reference Gf=12.5 × 10−3 J. This amount of dissipated energy is chosen according to the ones chosen in reference Gf between two steps of loading as depicted in Figure G1, starts at the peak load, and the second one, ΔG2, starts 10 loading steps after ΔG1, in the softening regime . The principle of post‐processing is simple: we track, during the increment ΔGf, all the C points  and a vertical axis (in the direction of the crack propagation). Afterwards, the distribution of these distances is plotted. For comparison purposes, the distributions are normalized with respect to the total number of distances computed, and the distances are divided by the ligament length of each beam.Histograms are computed from the distribution of the relative distances between points undergoing damage during an interval of dissipated energy ΔIn the case of pure tension, one would expect that the histograms are composed of two parts et al.Although these histograms cannot be interpreted as easily as in a pure tension test, some striking results are obtained: when the ligament length is kept constant, the histograms fall onto the same curve. It means that they are the same for a beam of depth 200mm, with a notch length of 100mm, a beam of depth 125mm with a notch length of 25mm and an un‐notched beam of depth 100mm. The same is observed for other sizes, as long as the ligament length is kept constant. Once the localized failure is initiated, the failure process seems to be solely influenced by the ligament length. This feature was also observed by Grassl Figures To summarize, on the one hand, the analysis of the distribution of distances between damage events provides results that are consistent with previous lattice analyses carried out on the same geometries. On the other hand, the distributions themselves exhibit effects because of strain gradient and correlation of failure events that seem difficult to separate, as opposed to the case of pure tension. A simple interpretation of these histograms, in terms of extraction of a correlation length for instance, is not straightforward. Because a major objective of this work consists of determining the capacity of the mesomodel to catch up relevant information on the mechanical behaviour of the structure at the local and global scales, the previously mentioned histograms and the distribution of dissipated energy during fracture shall be compared with experimental data.4et al.Three‐point bending tests were performed on geometrically similar notched and un‐notched specimens made of the same concrete material. The experimental results presented hereafter are obtained from a campaign similar to the one presented by Gregoire 4.1http://www.unibeton.fr) and detailed in Table The concrete formulation used here is based on a ready‐mix concrete mixture obtained from Unibeton , three FN200 fifth‐notched , two UN200 un‐notched  and three UN100 un‐notched specimens  have been tested. The thickness was kept constant (50mm). All tests were CMOD controlled at an imposed velocity (vCMOD). Table Figure 4.2dmin=1.25 cm to the location where the crack could appear was respected in order to minimize errors, which may occur when events are located near one sensor. Figure During the tests, acoustic events were recorded and localized. The AE system used in this study comprised an eighth‐channel MISTRAS system, a general‐purpose interface bus (PCI‐DISP4) and a PC for data storage analysis. Four acoustic transducers (resonant frequency of 150kHz) were placed around the expected location of the crack, on one side of the specimen. The AE event localization program relies on time‐of‐flight analysis and triangulation. The criterion used is that waves generated must reach at least three sensors. Then, the source location is determined by a 2D triangulation algorithm, which relies on AE arrival time and wave velocity. The details about AE setting parameters are given in The detected signals were then amplified with a 40‐dB gain differential amplifier in a frequency band from 20 to 120kHz. In order to limit the background noise, the signal detection threshold was set at a value of 35dB. The coupling between the transducer and the specimen is important in order to achieve a good accuracy of the localization of events. A thin layer of silicone grease was used to guarantee the correct transmission of acoustic signals between the beam and the transducer. The validation of both this coupling and the accuracy of the acoustic event localization followed the European standard NF EN 1330. It consists of verifying if the position of an on‐surface signal generated by the break of a short piece of pencil lead is correctly determined by the triangulation software. Thus, events were generated at several locations on the surface of each specimen, and the results from the localization software were compared with the true location of each event. A correct coupling is achieved when the accuracy of localization of these events is in the order of 4 mm.55.1et al.The experimental and numerical results in terms of force versus CMOD data are presented in Figure Figure 5.25.2.1d = 2.46 mm. Within each cell, the energy dissipation due to damage is computed for each lattice element located in the cell. The dissipated energy in a single lattice element is calculated as ΔDd=ΔωAh12ϵDϵ. Here, Δω is the increment of damage parameter; h, A, ϵ and D were defined in On one hand, the dissipated energy during damage is obtained numerically from the mesoscale analysis. Maps of dissipated energy have been already computed in On the other hand, the maps of the distribution of acoustic energy within the same loading increments are computed according to the same discretization. Within an increment, the energy of all the event contained in the same cell is summed up. Because of the localization resolution by the AE technique, less acoustic events than numerical events are detected. Therefore, the size and the discretization of the load increments are determined to ensure that enough events are captured experimentally in order to achieve statistically representative experimental histograms.Assuming that the acoustic energy recorded for each event is proportional to the energy dissipated during the corresponding damage event, it is possible to compare the dissipation maps during an increment of the load: D = 200 mm half‐notched, three D = 200 mm fifth‐notched, two D = 200 mm un‐notched and three D = 100 mm un‐notched specimens have been tested both experimentally and numerically. Three different loading increments are considered here corresponding to the same interval of dissipated energy (ΔG1=ΔG2=ΔG3=120 × 10−3 J). Figure In both approaches, the energy maps are averages from the same number of tests. Three 5.2.2Because the total energy dissipated within a cell is taken into account, the size of the cells has almost no influence on the dissipation maps. The size of the cells corresponds to the size of the discretization of the energy functional as in the numerical analysis of continuum functionals. However, a minimum size of discretization has to be respected because the energy functional is not continuous. Numerically, the minimum size corresponds to the lattice discretization. Experimentally, the minimum size corresponds to the resolution of the AE detection of the the acoustic sensors. Except for these minimums, the dissipation maps are similar whatever the size of the cells in the sense of the numerical analysis. The numerical minimum is far lower than the experimental minimum. Because the first goal of the paper is to test the relevance of the mesomodel by comparing the numerical results with experimental ones, we adopt the same discretization, which is driven by the experimental minimum. Numerical dissipation maps with a much lower cell size are presented alone in 5.2.3The length of the interval of dissipated energies has a significative influence on the results. By taking into account the interval of dissipated energies, the results represent an average. Because our first goal is to characterize the growth and evolution of the fracture process zone, we aim at considering the shortest interval of dissipated energies to perform the analysis. However, and unfortunately, there are intrinsic minimums of internal lengths that have to be respected. The first minimum corresponds to the loading step. No information is acquired experimentally nor estimated numerically between two loading steps. The second minimum corresponds to the fact that a minimum of damage events has to be captured to perform the post‐processing. Numerically, there is almost no limitation because many damage events are acquired within a loading step. Experimentally, this is much more restrictive because only few acoustic events are acquired by AE technique. Therefore, the size of the interval of dissipated energies are determined to ensure that enough events are captured experimentally in order to achieve a statistically representative post‐processing. Because the first goal of the paper is to test the relevance of the mesomodel by comparing the numerical results with experimental ones, we adopt the same interval length, which is driven by the experimental minimum. Numerical dissipation maps with a lower interval of dissipated energy are presented alone in 5.2.4Figures G1), in notched beams , similar trends are observed in notched and un‐notched beams.At first, one can remark that experimental results exhibit a more pronounced scattering than numerical ones. AE acquisitions are filtered to avoid spurious detection. A low filter threshold (35dB) is preferred to ensure that all events associated with micro‐cracking are captured. At the same time, with a low value, disperse and low‐energy events may be taken into account, while they are not associated with micro‐cracking. This may be a source of experimental scattering. Despite this scattering, the extents of the energy maps (which represent the FPZ) are similar. At initiation  but also local data (such as the distribution of energy dissipation). Comparisons between the distribution of relative distances between events will further document this conclusion. Numerically, a damage event corresponds to a lattice material point  and the AE analysis is itself 2D. The failure process is of course 3D, but four acoustic sensors have been placed on only one side of the beams, and therefore, the analysis of the AE localization is only 2D. A whole combined 3D study  should be performed to analyse the 3D effects, especially the shape of the FPZ on the surface boundaries.The following concluding statements can be made: the experimental inaccuracy in the acoustic event localization;the AE acquisition filtering;a 2D numerical analysis and a 2D AE analysis of a 3D failure process;the relatively few number of specimens tested experimentally; andthe relatively few number of damage events acquired experimentally and, consequently, the relatively large intervals of dissipated energy considered to achieve a statistically representative post‐processing.Discrepancies between experimental and numerical results may be due to the following: However, and despite all these sources of discrepancies, the overall agreement that has been observed between the mesoscale approach and the experimental data demonstrates that the mesoscale approach is capable not only of providing consistent global responses (e.g. force versus CMOD responses) but also capturing the local failure process realistically. The agreement between the distributions of the relative distances between damage events shows that the mesoscale model depicts the FPZ and its evolution during failure in a very consistent way compared with AE data. This conclusion opens the path for further analyses of the fracture process, solely based on numerical analyses with the mesoscale model, keeping in mind that the numerical model will be representative of the experimental reality. From these studies, a better understanding of the correlations between damage events that should result in nonlocal continuum modelling at the macroscale is to be expected.


For highly sensitive magnetic measurements, e.g., a measurement of the neutron electric dipole moment (EDM), the magnetic field has to be stable in time on a level below picoTesla. One of several measures we employ to achieve this uses an external field coil system which can stabilize the ambient external field at a predefined value. Here we report on the construction and characterization of such a system in the magnetic test facility at PSI. The system actively stabilizes the field along the axis of the EDM experiment by means of four coils in a Helmholtz-like configuration. Additional coils serve to compensate for transverse ambient field components. Because of the long integration times in the EDM experiment (about 100 s or more) only slow disturbances have to be corrected for. The performance of the system has been measured using static and moving magnetic sources and suppression factors in excess of 200 have been observed. The influence of magnetic fields on sensitive equipment can be reduced by up to several orders of magnitude by passive shielding with soft iron alloys . The suppression factor obtained in this way depends on the geometry of the shielding system, the shielding material properties and the characteristics of the field. For large volumes and unfavourable geometries—as they may be dictated by other requirements of the experiment—passive shielding may not be sufficient and other means of field stabilization or field noise reduction have to be applied. For instance, in the new experiment to measure the neutron electric dipole moment (EDM) in preparation at PSI the magnetic field has to be stable in time on a level below pT. This has to be compared to the amplitude of the natural and man-made variations of the magnetic field which can be as large as 100 nT in our case. Since most of these disturbances vary on a timescale of minutes to hours and the EDM experiment is essentially insensitive to moderate disturbances on a timescale below about 10 s we decided to test an external Helmholtz-like coil system which would be able to cancel slow ambient field variations. The basic idea is simple and similar to that of normal Helmholtz stabilization systems: a pickup sensor measures the ambient field value near the sensitive device, from which an error signal is derived with respect to a selectable set value. The error signal is converted into a current signal which is then fed to the external coil system surrounding the device. If the device has its own magnetic shielding, then the question arises whether the pickup sensor should be located within the passive shielding or outside. For good passive shielding, e.g. using at least 3 to 4 layers, the suppression factor due to the passive shielding alone is usually better than 1000 and the field level inside the shielding can get into the regime of several tens of pT. At this level the momentary field value measured by the pickup sensor may become influenced by ‘shielding’ noise which has nothing to do with changes of the ambient field outside. Thus there is no constant relationship between an outside disturbance and the corresponding correction signal and the stabilization will eventually break down.k as high as 400 have been observed [k is close to the limit imposed by the stabilization electronics system and is no measure for the suppression due to a realistic disturbance at large distances, i.e. ≥ 30 m. The suppression of what is stated as ‘real’ environmental noise is mentioned in Ref. [k ≤ 2 at frequencies around 100 mHz [Several such stabilization systems have been described in the literature, either in combination with soft-iron shielding –3, or wi in Ref.  but not z  and coincides with the axis of the EDM experiment. Its centre was defined as the origin of the coordinate system. The axial suppression factor of the shielding is predicted to be on the order of 103, while the transversal one should be by about a factor of 10 higher. Therefore the main requirements for the external coil system were tozB) and actively stabilize this component on the basis of feedback sensors. The bandwidth of the stabilization should be in the range of about 0.001 to 1 Hz in order to eliminate slow to medium-fast variations due to natural changes of the Earth field, slow truck movements, crane and elevator movements, magnets etc.Provide zero or near-zero field in the axial direction . This is required to optimally demagnetize the outermost permalloy shield.Compensate for the static ambient field and provide zero or near-zero field in transverse directions (The principle of the experiment is sketched in x (y) direction. These two coil systems are powered in constant-current mode.two rectangular coils for each transverse direction (3 m by 4.6 m) in a Helmholtz-like configuration at a spacing of 1.8 m (3m) for the 4 rectangular coils for the axial direction (3 m by 3 m) at 1.8 m and 4.2 m spacing to provide near-homogeneous field compensation over the 1.6 m length of the shielding. The 4 coils are connected in series and are powered by the stabilization power supply which is controlled by a correction signal derived from one (or two) fluxgates.x) were mounted directly on the main coils. These were used to stimulate artificial field variations in order to measure the ideal suppression factor as a function of frequency. They could be powered by a special power supply which was stimulated by a signal generator to produce a sinusoidal current excitation with adjustable amplitude and frequency.2 independent test coil systems . The external coil system consists of:The digital regulation system uses the fluxgate input signals  which are sampled at about 50 kHz and filtered with a simple low-pass filter at about 240 Hz. After digitization the values are compared to a selectable set-value and the correction values thus produced are sent to the power converter with maximum amplitude 7 A/20 V. The control system consists of two nested control PI loops, the parameters of which were specified by empirical trials. The sensors used are 3-axial fluxgates (Bartington Mag-03MC).zk = zBstab off/zBstab on was determined from the peak-to-peak amplitudes of zB with and without stabilization. Given the close-to-ideal spatial matching between test coil and compensation coil one expects large suppression factors, limited essentially only by the stabilization electronics. Indeed, the measured zk values ranged from ∼10 at 50 Hz to ∼104 at 1 mHz. The frequency response of the stabilization was optimized for frequencies ≤ 1 Hz.The electronic performance of the stabilization was tested with a sinusoidal stimulation of the test coils (which have the same geometry as the Helmholtz coils) and using one fluxgate in the centre of the apparatus as feedback sensor. This was done before installation of the permalloy shielding. The suppression factor −1/2 for large measurement volumes. The Cs quantum magnetometers used here operate in self-oscillating mode with gas-discharge driven Cs-lamps. The small magnetic field (zB ≈ 2 µT) required to operate the magnetometers (and the EDM experiment in future) was provided by a solenoid mounted inside the shielding and driven by a highly stable current source. Any transverse, external field component transmitted through the shielding is thus negligible with respect to this solenoid field and the magnetometers—which are in principle scalar devices—measure essentially only the zB component. 5 magnetometers were available which could be moved along the z-direction in the 5 channels indicated in Next, we included the permalloy shielding and the Cs-magnetometer system. The axial shielding factor of the shielding  was found to be about 100. This is a factor 20 below expectation, however consistent with low measured susceptibilities and is attributed to improper tempering of the fully welded shielding cylinders. Good demagnetization can be achieved with an induction transformer, delivering a smoothly decreasing demagnetization current. The Cs-magnetometer system was developed at Vavilov State Optical Institute, St. Petersburg  and IoffThe external coil system is enclosed in a thermal housing which, in combination with a temperature stabilization system, provides stable temperatures on a level below 0.1 K.x = −7 m, y ≈ 50 cm, z ≈ 0 and its axis parallel to z. It produced zB amplitudes ≤ 100 nT at the center of the device, i.e. at x = y = z = 0 . The solenoid was simply used in on/off mode with signal duration of several seconds. For moving sources we employed various types of vehicles which were driven along the road parallel to z at about 11 m distance. This is a situation identical as for the future site of the EDM experiment. The measurement procedure was as follows: the response of the Cs magnetometers within the shielding to the external magnetic source was measured, with and without application of the stabilization system and the suppression factor zk calculated as defined above. The pickup sensor position was varied, but always as close as possible to the shielding (i.e. with minimum 1 cm spacing), below and above the shielding, i.e. at x = 0, y = ±50 cm, z variable. Results are given in zk| is plotted vs. the pickup sensor position, for the stationary and the dynamic case (where for clarity we have only displayed the two points with maximum suppression). For both types of test sources the sensor location was found to be very sensitive, such that a shift of a few cm destroyed the good performance with |zk| ≥ 200. For the static case over-compensation (zk < 0) was observed for z-values between the two maxima and under-compensation (zk > 0) elsewhere. It should be noted that our stationary test geometry is similar to the one reported by Ref. [For testing we employed stationary as well as moving magnetic sources. In the first case we used a small solenoid positioned at zk correspondingly large. The uncertainty for zk is estimated to be on the order ≤30 % for large zk for the following reasons: (a) in the stationary case the signal level (≈5 pT) for large zk is close to the noise level; (b) in the dynamic case the data taking rate for the Cs magnetometers is fixed to 1 Hz and given the time structure of the signal with stabilization large uncertainties must be expected after integration due to such a coarse time binning.The response to a dynamic source is shown in zk(stationary) was measured at small zk with lower excitation amplitudes and found to be valid over the range 10 to 100 nT. In the dynamic case we also used other types of vehicles producing smaller disturbances  with essentially the same results. We also tested whether zk depends on the Cs-magnetometer position within the shielding and found that it is essentially homogenous over the tested position range |z| ≤ 50 cm.The linearity of z at x ≈ 4 m. Large zk was observed only for a very narrow range of positions (−10 cm ≤ z ≤ +10 cm) around z ≈ 0. Outside this optimum range zk quickly dropped and remained more or less constant at zk ≈ 5.While for the dynamic case the test scenario corresponds perfectly to reality, the stationary test case used is specific for the position of the test solenoid and applies only for a disturbance signal arising at a fixed position (a similar case was tested in Ref. and yielB(t) = cB(t) − (ΣiB(t))/4, where cB(t) is the reading of the magnetometer at x = y = z = 0 and the iB(t), i = 1,..4 are the readings of the 4 magnetometers in the outer channels at z = 0  with a LTS-SQUID magnetometer , provided by PTB Berlin. The results  demonstrA 3-dimensional external stabilization system in Helmholtz-like configuration was built and tested in conjunction with a 4-layer permalloy shield and the pickup sensor outside the shield. Measurements in dc mode with a stationary test solenoid yielded suppression factors ≥200 for certain positions of the pickup sensor. This however only applies for well defined placement of the test solenoid. Signals from moving vehicles on a nearby road parallel to the system axis are suppressed by a factor of about 200, again strongly dependent on the pickup sensor location. Finally, real ambient noise was found to be suppressed by a factor 10 to 20 in the frequency range 1 to 10 mHz.


Painful spinal metastases have been treated with conventional radiotherapy for decades, but one-third of the patients have insufficient pain relief after treatment and one-fifth need retreatment. Stereotactic radiotherapy is a method to increase the dose in the spinal metastases with a potentially longer lasting palliative effect without increasing the side effects of the treatment and thereby is expected to improve the quality of life significantly.This study is a multicenter prospective randomized clinical trial comparing conventional radiotherapy (1 x 8Gy) with stereotactic radiotherapy (1 x 20Gy) for pain reduction and quality of life in patients with painful spinal metastases. A total of 386 patients will be randomized between the two treatment groups. Besides pain measured by the Dutch Brief Pain Inventory, quality of life and cost-effectiveness also will be measured. The primary outcome is pain reduction at 6 weeks after treatment. Secondary outcomes will be the time to pain response, duration of pain relief, health-related quality of life and toxicity, as well as cost-effectiveness.This study investigates whether stereotactic radiotherapy with dose escalation for symptomatic spinal metastases can lead to improved pain reduction as compared to conventional radiotherapy without an increase of treatment-related side effects. These results will contribute to the optimization and individualization of the treatment for the patient.NCT02407795 .ClinicalTrials.gov identifier  Many patients diagnosed with cancer have already metastasized disease or will metastasize in time. When there are no curative options, treatment will be focused on maintaining optimal quality of life. Up to 70 % of all bony metastases are located in the spinal column. Spinal vertebral metastases can give serious pain complaints, which are likely to progress in time and thereby decrease the quality of life . BesidesConventional radiotherapy has been used for decades for palliation of pain caused by bone metastases. Patients are treated in a single or multiple fractions. Generally, a reduction in pain will occur in two-thirds of patients within 4 to 6 weeks after irradiation. Retreatment is necessary in up to 24 % of all patients . BecauseStereotactic body radiotherapy (SBRT) allows dose escalation to the spinal vertebra or paraspinal tumor with steep dose gradients that limit exposure to the spinal cord and other organs at risk. As the dose to the non-involved organs at risk is strongly reduced, fewer side effects will be expected compared to conventional radiotherapy. Due to the biologically higher dose that can be given to the target volume compared to conventional radiotherapy, better results are anticipated, especially when more radio-resistant tumors like renal carcinoma or melanoma are treated. Another question to be answered is whether we can identify a subgroup of patients that will benefit more from high dose stereotactic irradiation as compared to the conventionally used single fraction of 8Gy radiotherapy.No data are available from randomized clinical trials comparing the standard 8Gy to SBRT high dose, nor are there dedicated phase I dose escalation studies. The total dose and the fractionation schemes have been mainly dependent on the physician . The firThe aim of this study is to investigate whether stereotactic radiotherapy for symptomatic spinal metastases can lead to improved pain reduction as compared to conventional radiotherapy, without an increase of treatment related side effects and thereby result in a better quality of life. The primary objective is pain reduction, but we also focus on the duration of pain relief as an important secondary endpoint besides quality of life and cost-effectiveness. To answer these questions, an intensive scheme of time points for questionnaires and pain scores will be used. These results will contribute to the optimization and individualization of the treatment for the patient.This is a multicenter, prospective randomized clinical trial to investigate pain reduction after radiotherapy. Two different radiation doses will be evaluated: 1 x 20Gy by SBRT and 1 x 8Gy conventional radiotherapy.The primary objective is to investigate whether stereotactic radiotherapy for symptomatic spinal metastases can lead to improved pain reduction as compared to conventional radiotherapy without an increase of treatment-related side effects. The primary endpoint will be pain reduction after treatment. Secondary endpoints are time to pain response, duration of pain relief, quality of life, and toxicity. In addition, cost-effectiveness will be studied.Patients must be able to undergo radiotherapy and fulfill the eligibility criteria. The diagnosis of a solid tumor must be pathologically confirmed to make the patient eligible for the study. The extent of the metastases in the spine should be visualized on an MRI, no longer than two weeks before randomization or no longer than 6 weeks before the start of treatment. To determine the clinically relevant category of stability, the Spinal Instability Neoplastic Score (SINS) will be obtained and documented prior to treatment. Earlier studies showed that the sensitivity of SINS for potentially unstable or unstable lesions was 95.7 %, with a specificity of 79.5 % , 15. WriThe study is designed to be carried out in multiple centers in the Netherlands. Patient randomization will only be allowed from authorized investigators, their authorized staff members, or data manager. A patient can be randomized only after verification of eligibility. In case a patient is eligible and a written informed consent is obtained, the randomization form must be faxed or digitally sent to the Data Center. Randomization will be performed using a password-protected database (OpenClinica). Patients will be stratified on primary tumor type , Karnofsky performance status (60 to 70 versus 80 to 100) and number of spinal metastases .Histologically proven solid tumor with radiological diagnosis of spinal metastasesPain score minimum 2 on an 11-point scale (0 = no pain to 10 = worst imaginable pain)Maximum of two consecutive or noncontiguous spinal segments involved by tumor at current level of interestGross tumor optimally > 3 mm from the spinal cord on MRIKarnofsky performance status ≥ 60WHO 0-1-2Life expectancy > 6 weeksAge ≥ 18 yearsNonpregnant, nonlactating female patients. Sexually active patients of childbearing potential must implement effective contraceptive practices during the studyWritten informed consentInclusion criteria are as follows:History of previous radiotherapy to the spine at the current level of interest or overlapping locationChemotherapy or targeted systemic therapy within 14 days of radiotherapySpinal instability or neurological deficit resulting from bony compression of neural structuresPathologic fracture or impending fracture needing surgical fixationPrior surgery to the spine at the current level of interest or overlapping locationGross tumor < 3 mm from the spinal cord on MRIMore than 25 % spinal canal compromisePatients with a pacemaker such that MRI cannot be performed or the treatment cannot be delivered safelyPatients not able to undergo MRIEarlier nuclear medicine treatment for example strontium 89 treatmentPregnancyAltered mental status that would prohibit the understanding and giving of informed consentExclusion criteria are as follows:Days 0 to 14: their daily average, worst and present pain, intake of medication (dosage), and effect of medication (BPI)Days 0, 7, and 14: effect of their pain on quality of life items Weeks 4 and 6 and months 2, 3, 4, 6, 9, 12, and thereafter, every 6 months with a maximum of 5 years or until death, both the BPI and QOL questionnaires. Concomitant use of analgesics should be noted.Time to response is calculated from the date of randomization. Pain is self-reported by the patient and will be measured by an adjusted version for daily use of the Dutch Brief Pain Inventory (BPI). The BPI assesses pain on a 0–10 scale, where 0 is no pain and 10 is worst imaginable pain. It also has a questionnaire that consists of questions on severity of pain, impact of pain on daily function, location of pain, pain medications, and amount of pain relief in the past 24 hours or the past week. It is a short questionnaire that requires 5 minutes to complete. The BPI has been validated in more than 25 different languages. Response to treatment is calculated taking into account changes in the administration of opioids. Quality of life will be assessed using the EORTC QLQ-C15-PAL and the EORTC QLQ-BM22 –18. ThesPost-treatment diagnostics should be performed according to the institutions routine guidelines. Recurrence of disease should preferably be confirmed using MRI. Tumor growth less than 25 % is classified as stable disease. Data needed for re-irradiation and the occurrence of spinal cord compression and/or fractures, along with data on systemic treatment are collected at 3-month intervals at the institutes.The pain score will be divided into four response categories for analyses. Complete response (CR) is defined as a pain score of 0 at the treated site, with no concomitant increase in analgesic intake. Partial response (PR) is defined as a pain reduction of 2 or more at the treated side on a scale of 0 to 10 without analgesic increase, or an analgesic reduction of 25 % or more from baseline without an increase in pain. Pain progression (PP) is defined as an increase in pain score of 2 or more above baseline at the treated site with stable analgesic intake or an increase of 25 % or more in analgesic intake compared with baseline with the pain score stable or 1 point above baseline. Stable pain (SP) is defined as any response that is not captured by the complete response, partial response, or pain progression definitions. Responders are defined as CR + PR; nonresponders are defined as PP + SP.For conventional radiotherapy, a single dose of 8Gy will be given using a linear accelerator with at least 6 MV photons. Preferably patients are treated using the ICRU guidelines, but there are no restrictions formulated with respect to the radiation technique. Patients should be treated according to the standard treatment protocol per institution.For stereotactic treatment 1 x 20Gy), patients will be prepared with a dedicated CT simulator in treatment position with an immobilization device as used per institution. Standard position is supine, no prone position is allowed. Scans should be matched with the pretreatment (diagnostic) MRI images as they provide better delineation of the tumor and the spinal cord than the simulator CT scan. Target volumes are defined according to the ICRU Reports 50 and 62 and according to the International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery Gy, patie. CircumfThe primary outcome of interest in this study is a reduction of pain of 2 points at 6 weeks since baseline. The literature shows that in patients with conventional radiotherapy the percentage of patients with pain reduction ranges from 66 % to 72 %. We assume that the percentage of patients with pain reduction is 70 % in the group with conventional radiotherapy compared to 85 % in the group with stereotactic radiotherapy. Therefore, 135 patients are needed in each group to obtain a power of 80 % . We adjust for a drop-out rate of 30 % and will include a total of 386 patients. The primary analysis will be the comparison between the two treatment arms of the proportion of patients with pain reduction, defined as a decrease in pain score of at least 2 points from initial pain score, at 6 weeks. Time to pain progression, radiation-induced fracture and/or death will be calculated from date of randomization to the documentation. For the calculation of response, no fixed time interval from the date of randomization will be applied. Response of treatment will be calculated if at least two successive follow-up pain scores are available.The protocol has been written and will be conducted according to the ICH Harmonized Tripartite Guideline for Good Clinical Practice. The study protocol was approved by the Central Dutch Medical Ethical Committee of the Radboud University Medical Center Nijmegen (2014). The regulations regarding medical confidentiality and data protection are fulfilled.The aim of this trial is to test the hypothesis that stereotactic radiotherapy gives a better and longer lasting reduction of pain, better local control, and therefore a better quality of life without an increase of treatment-related side effects compared to conventional radiotherapy for symptomatic spinal metastases. Recent trials and reports using SBRT show excellent local control and a fast pain reduction in 1 to 2 weeks when treating painful spinal metastases , 22–26. Quality of life is an important issue in cancer patients at all stages of disease. Quality of life is affected by many factors such as the disease itself, but also psychological and social factors. In patients with pain, the quality of life can be impaired due to the pain or the disease itself but also by the multiple treatments to which patients are exposed. The minimization of hospital visits is important. Furthermore, the analgesics can give side effects that may have a negative impact on the quality of life. Radiotherapy can reduce pain resulting from bone metastases and reduce analgesic use and it side effect, thereby improving the quality of life . KnowledThe question to be answered is whether we can identify a subgroup of patients that will benefit from a high dose stereotactic irradiation and consequently have a better quality of life as compared to the frequently used single fraction of low-dose conventional radiotherapy. This in order to optimize and to individualize the treatment options for the patient.This trial began in May 2015 and is currently recruiting.


As a continuation of the work on the ventilation requirements for a bicycle helmet for commuters , 15 fullThe helmets were tested in the wind tunnel placed in a climatic chamber at 34 °C and 40 % relative humidity (water vapour pressure in the air 2200 Pa) with the air velocities set to 1.6 m/s (≈6 km/h). Tests were performed on the head model without a wig. Evaporative resistance was calculated from heat loss corrected for the difference in head surface to textile skin temperature , and oneThe prototypes differed largely in evaporative resistance Figure .The best reference helmet from the earlier study  stayed aThe best helmet from the evaporation viewpoint was different from the best in terms of insulation. This means that a best solution for a commuter has to be defined by the user's bicycling activity, the weather conditions etc. The newly designed helmets' results can be used as the basis for improvement of helmet ventilation.


Serial operation of FEL experiments was performed using the spent beam typically discarded after passing through a hole in a detector. The beam profile was characterized and results for two simultaneous experiments are reported. X-ray free-electron laser sources such as the Linac Coherent Light Source offer very exciting possibilities for unique research. However, beam time at such facilities is very limited and in high demand. This has led to significant efforts towards beam multiplexing of various forms. One such effort involves re-using the so-called spent beam that passes through the hole in an area detector after a weak interaction with a primary sample. This beam can be refocused into a secondary interaction region and used for a second, independent experiment operating in series. The beam profile of this refocused beam was characterized for a particular experimental geometry at the Coherent X-ray Imaging instrument at LCLS. A demonstration of this multiplexing capability was performed with two simultaneous serial femtosecond crystallography experiments, both yielding interpretable data of sufficient quality to produce electron density maps. FELs, however, by their very nature are very different from any previous synchrotron source and even from the other members of the fourth-generation class. They have a fundamentally different look with long linear facilities as opposed to the circular structures of synchrotron sources. This linear construction with single-pass acceleration of ultrashort electron bunches is at the source of the uniqueness and power of FELs, but the cause of the greatest frustration with them, which is the limited amount of beam time. In contrast to ring-based facilities which support multiple sources around the ring, linear-accelerator-based facilities can produce typically only one source at a time. Although new facilities will soon be capable of using multi-bunch modes and high repetition rates to distribute the electron pulses to multiple undulators and beamlines with fast kicker magnets, the number of sources and, therefore, the number of simultaneous experiments that can be performed at FEL sources will likely remain small for the foreseeable future.X-ray FELs allow the generation of X-ray pulses with enough photons to produce measurable and interpretable signals from a single shot but that are also of ultrashort duration approaching or even reaching time-scales of electronic processes. For example, Auger decay life-times, typically on the order of a few to roughly 10 fs, are on the same time-scales as FEL pulse durations, which range between ∼5 fs and ∼100 fs. Furthermore, such short pulses can traverse the sample faster than the time-scales required for significant atomic motions, allowing snapshot data collection where the sample does not have time to move or change.et al., 2000This realisation has led to the idea that radiation damage, which regularly presents a limitation in studying organic samples at continuous X-ray sources, could be greatly mitigated using the pulsed sources afforded by X-ray FELs. A single short pulse contains many more photons than would be necessary to cause irreparable damage to the sample using a time-integrating source focused to a micron-scale spot. All this incident energy, when the beam is tightly focused, leads to rapid sample charging and heating and ultimately the destruction of the sample. This process is, however, slower than the pulse duration leading to what is now known as the diffraction-before-destruction technique   system  with the 1 µm (microfocus) system comprised of the 1 µm KB system (KB1), the 1 µm sample chamber (SC1) and the detector shown in purple; while the components of the 100 nm system, the 100 nm KB system (KB01), the 100 nm sample chamber (SC01) and its associated detector, are shown in green. The long focal length of the 1 µm KB system is required by the 420 m source distance and 30–60 µm FWHM source size in order to produce a FWHM focus in the order of 1 µm. This large focal length led to significant empty space along the beamline between the focusing optics and the 1 µm sample chamber. To optimize the limited floor space, this empty gap was filled by the entirety of the 100 nm (nanofocus) system shown in green in Fig. 1b). The optical path of the microfocus beam from the mirrors to its focus passes completely by the nanofocus mirrors and focal plane [see Liang et al. (2015b), the microfocus mirrors are shown out of the beam path as they are retracted when the nanofocus mirrors are in use. Conversely, when only the microfocus mirror system is in use, all components of the nanofocus system are removed from the beam path.As described previously . The two sample chambers can be used simultaneously by aligning the entire beamline on the 100 nm KB axis and utilizing the microfocus chamber for the secondary interaction point. The beam passing through the hole in the primary detector diverges until it intercepts a set of beryllium lenses that have been selected to properly refocus the beam of a desired photon energy. These lenses are mounted on an existing port on top of the detector chamber to locate them as close to the primary focus as possible, in this case 1 m. The system allows for three sets of lenses mounted to a single bracket that can be positioned transversely to the beam for proper centering of the lens clear aperture on the beam. Three different photon energies can then be used without any physical modification to the system, at the press of a few buttons.The experimental geometry is shown in Fig. 1b) is a beam profile monitor (labeled Diag) which consists of a fluorescent screen that can be inserted between the two interaction points to characterize the beam profile downstream of the refocusing lenses but prior to reaching the secondary focus. Images from this screen are shown in Fig. 2The relevant components and their relative distances are listed in Table 13.o is the object distance from the optical element and i is the distance of the image from the optical element. The image magnification is given by Geometrical optics can be easily used to calculate the expected beam profile at both the primary focus and the refocused plane. Using the calculated source size and location of LCLS, 30–60 µm FWHM (depending on the photon energy) and 420 m, respectively, one can calculate the focus sizes and location assuming perfect optics by using the thin lens equation E is the photon energy. The LCLS beam has a typical bandwidth of 0.2% FWHM which usually does not represent an issue when using lenses as the primary focusing element. Under such usual circumstances, Be lenses are used to focus the incident LCLS beam with a source distance much larger than the distance to the focus. This is a demagnifying optical system which creates at the focus an image of the source that is smaller than the source. As can be obtained from the thin lens equation, under the condition that et al., 2013However, continued use of geometrical optics calculation for the refocused beam will give a significantly wrong answer for the presented geometry for two primary reasons. First, the Be lenses used for refocusing are chromatic with the focal length versus 1 m). In the same way a demagnifying system keeps the image at a similar position for large changes in the source location, a magnifying system will move the image significantly for small changes in the source location, or equivalently for chromatic optics, small variations in the focal length of the optics. Therefore, chromaticity plays an important role in the configuration presented here. A simple application of geometrical optics ignoring chromaticity for the experimental geometry presented here would produce a ∼350 nm The refocusing system used here is, however, a magnifying system, where the image distance is larger than the source distance , to first order, the behavior of the refocused beam size is similar for all photon energies used as long as a Be lens stack with suitable focal length is used. Therefore, for the experimental geometry presented here and an LCLS self-amplified spontaneous emission (SASE) beam, a minimum spot size of 2.5 µm FWHM should be expected, with significant sensitivity to energy fluctuations which can occur from day to day, likely requiring checking the focus periodically. Also playing a role in the optimal photon energy for refocusing is the tuning of the machine and the beam divergence from the source on any given day, which may be sufficiently different to slightly change the focal plane. The use of a self-seeded beam  are expected with LCLS and FEL and the upper bound obtained here, including vibrations of the imaging system, are consistent with the expectations.5.The characterized refocused beam using the ∼7.6 keV lens stack was used to perform two simultaneous and independent experiments within CXI using the geometry shown in Fig. 1et al.  was mixed rapidly with 7.5 ml precipitant solution  and left overnight at 277 K on a vertically rotating turntable. After settling of the crystals, the crystal growth solution was exchanged several times for storage solution . Before data collection, the crystalline slurry was filtered using a 20 µm stainless steel inline filter. The final sample contained approximately one-third solid settled crystalline material by volume.Data were collected from lysozyme microcrystals, using smaller crystals  to identify possible Bragg reflections on the offset-corrected and bad-pixel-masked images. A set box size of 4 For the refocused data set, a different approach was required because of the poorer characteristics of the second detector used for this sample chamber. This detector had an out of the ordinary large number of bad (hot) pixels easily confused with signal. Also, the Bragg reflections in the refocused data set encompassed fewer pixels and were weaker in comparison with the primary data set. Therefore, a later version of Because of the different characteristics of the two detectors, the settings for bad pixel identification needed to be different. While for the upstream detector a fixed upper threshold of 4.3 ADU was sufficient, the noise characteristics of the downstream detector were unusually bad. Therefore, an additional lower boundary needed to be included. The range for which noise was acceptable was set from 2 to 7 ADU. Pixels with noise values greater or less than this range were masked as bad.et al., 2012The additional threshold for bad pixel identification and the different approach on identifying hits were essential for successful analysis in the downstream experiment as otherwise the fewer hits found with the same approach could not be indexed. This was not due to the refocused beam itself but rather to the detector characteristics, likely caused by accumulated damage to pixels over months of operation  yielding two simultaneous interpretable data sets from the same LCLS pulses.et al., 2015It also validated simulations that will be used to estimate the refocused beam size for a new system under development at CXI, the serial sample chamber (SSC). It will allow the very same concept presented here to be used for the microfocus KB system instead of the nanofocus KB system . While it is expected that SFX experiments will continue to become more reliable, simple measurements only requiring a small amount of beam time such as protein crystal screening could be best suited to this mode of operation.10.1107/S1600577515004002/yi5010sup1.pdfExamples of the simulations performed. DOI: