Ghana is currently experiencing electricity supply crisis that is believed to have some impact on the mental wellbeing of the population, especially among university students that have become increasingly dependent on uninterrupted electricity supply to fully function academically. There is no known study that explores the link between infrequent electricity supply and generalized anxiety disorders in sub-Saharan Africa. This study aimed to explore that link and determine the proportion of university students whose anxiety levels may be influenced by the electricity supply crisis that the country is experiencing at the moment.This exploratory study used the Generalized Anxiety Disorder 7-item scale (GAD-7) to conduct the study on the University of Ghana campus. The likelihood ratio (LR) test and Fisher’s Exact tests were used to determine any association between the electricity supply crisis and anxiety levels among students. Unadjusted odds ratio and corresponding confidence intervals were estimated and ordinal logistic regression technique was used for the effect of covariates on anxiety.Overall, nearly 26 % of students interviewed felt nervous, anxious or on edge almost every day due to the erratic power supply. The proportion of students determined to be classified having minimal, mild, moderate and severe anxiety due to the erratic power supply was 24.2, 30.7, 22.1 and 23.1 % respectively. Students were significantly more likely to be anxious if the frequency of power outage increased .Our finding in this study suggests that although the erratic power supply does not allude to any clinical confirmation of the students having anxiety disorders, it does point to a fact that even in a resource-poor country like Ghana, where constant supply of electricity is not always guaranteed, students may not be entirely immune to the health and well-being implications of failures in some sectors of the economy such as power supply. The magnitude of recent electricity supply crisis in Ghana is not unprecedented. However, the frequency of the current power cuts in an environment of a growing middle class, including university students—that have become accustomed to modern amenities which rely on regular electricity supply—is believed to have had an effect on the mental health of Ghanaians in the immediate and long-term .The World Health Organization estimates that globally about 25 percent of a country’s population will suffer from a mental disorder in their lifetime, and at any point in time about 10 percent suffers from a psychiatric condition of which an estimated three percent in Ghana is believed to have severe form of mental disorders at any point in time .In Ghana, it is estimated that about 18 psychiatrists and about 1200 mental health nurses are known to be actively practicing for the estimated 2.5 million Ghanaians who suffer with at least one mental disorder . The shoMany factors are responsible for people experiencing mental disorders in their lifetime. These include physiological, personal history or lived experiences and environmental factors , 7. The Ghana is currently experiencing electricity supply crisis, particularly in the highly populated and urban areas, including the Greater Accra Region where many institutions of higher learning are located. The electricity supply crisis has had some impact on the socio-economic wellbeing of people, including students at institutions of higher learning such as the University of Ghana. Students in this university are dependent on the regular electricity supply to carry on with their normal academic and other lifestyle activities. Therefore, the infrequent supply of electricity to the university community would undoubtedly affect the students’ lifestyle, including their mental health and wellbeing. College students are normally confronted with a myriad of issues including academic, social and personal that has potential to influence their mental health. These issues generally would tend to change depending on the students’ socio-demographic factors as well as their progression in age, academic experience and socioeconomic status while living on campus .The electricity supply crisis in Ghana, which is a systemic issue, is believed to have influenced the health and mental wellbeing of tertiary level students even more because the student population is made up of individuals who have become so dependent on modern technology such as smart-phones, tablets, laptops and other personal computers for their routine academic activities. These gargets are themselves, as well as the internet connectivity to enable them to function, heavily dependent on electricity supply for normal functionality. Therefore, the infrequent electricity supply to the university community is likely to impact on the anxiety levels of students who require regular power supply to function effectively.Generally, there is limited population level research not only on anxiety and stress levels but on mental health as a whole in Ghana . In factThe study was conducted on the University of Ghana campus. The University of Ghana is the oldest and largest public university in the country. The university was founded as the University College of the then Gold Coast in 1948 for the purpose of providing and promoting university education, learning and research in the British colony. The university currently has a student population of 29,754, which constitutes undergraduate and graduate students. The undergraduate students constitute about 88 % of the total student population and the male to female population is 2:1.This stratified cross sectional study used the generalized anxiety disorder 7-item scale (GAD-7) developed by Spitzer et al.  as a briScores from the self-administered questionnaire, when added together, is categorized as follows: 0–4 = minimal; 5–9 = mild; 10–14 = moderate; and 15–21 = severe anxiety disorder. The socio-demographic variables measured in the study included age, sex, marital status, education level and religion.p < 0.05, The sampled population consisted of the University of Ghana students who are residents within the campus of the university. All students were recruited directly from their respective hall (dormitory) of residence during the 2014/2015 academic year when the erratic electricity supply was more severe. The minimum sample size needed for the study was approximately 578 based on the following assumption:P is the expected proportion of the population with anxiety disorder. Since this is unknown, the default proportion of 0.5 was used. The margin of error ‘e’ is 5 % with design effect of 1.5. By substituting the above parameters in Eq. .The likelihood ratio (LR) test and fisher’s exact test with their corresponding p values were used to determine associations between each categorical predictor and level of anxiety among students. Socio-demographic factors that were significantly associated with intensity of anxiety from the LR test were included in the multivariable analysis. Unadjusted odds ratio and corresponding confidence intervals were estimated. In assessing and quantifying the effect of covariates on the intensity of anxiety, ordinal logistic regression technique was used. Proportionality assumption for ordinal logistic regression was tested using the Brand’s test. Standard error estimation was based on bootstrapping technique. Hierarchical backward selection technique was used in determining parsimonious model. The Cronbach’s alpha was used to estimate reliability coefficient for the GAD-7 scale. Proportion of missing values was only 0.15 %. Unless otherwise stated, significant associations were observed at Ethical clearance for this study was obtained from the University of Ghana’s ethical review committee for the humanities (ECH). The study investigators additionally obtained permission from the University of Ghana Dean of students as well as Hall Masters of all the various halls of residence for students who reside on campus.Interviewers obtained written informed consent from each participant in the study. They were informed of their right to refuse participation in the study. Students were assured that they would not be coerced into participating in the study and that refusal to participate would not incur any reprimand since it was a voluntary study.The questionnaires administered did not bear the names of participants or codes that could directly link them to specific responses. Interviews were conducted in the rooms of participants having indicated that they were comfortable with that. The administered questionnaires were coded and kept securely. Further, the data collected were used solely for the purpose for which it was intended.The total number of study participants was 650. All the participants were recruited from all of the 13 halls of residence located within the confines of the university. Of these, 344 (53.3 %) were males and 302 (46.7 %) were females. The mean age of the students was 21 years (SD 2.3) with the youngest and oldest participants aged 17 and 39 years respectively. Students from the humanities represented 76.8 % of the total number of students sampled for the study; Basic and applied sciences, 17.3 %; and other programs, 5.9 %. All but five students did not indicate their academic level. Of the 645 students that indicated their current academic level at the time of the study, 642 (99.5 %) were undergraduate students with 242 (37.5 %) being in their second year of study. The number of postgraduate students was three (0.5 %) and almost all of the participating students were not married 637 (98.2 %). See Table Table The availability of stand-by power generator in the hall of residence and the frequency of electricity power outage were significantly (p < 0.05) associated with level of anxiety Table . The oddThe proportion of students that used other sources of light when there was no electricity power supply was as follows: Rechargeable lamp (21.9 %), torchlight (19.5 %), cell phone (20.6 %), candle (6 %), two or more of the light sources stated above (22.5 %), other light sources different from the ones stated above (3.2 %) and no other light source whatsoever (10.8 %). Regarding the activities carried out when there is electric power cut, the distribution of the students was as follows: Go to other halls of residence that had electric power (13.9 %); go to lecture theatre (5.7 %); leave the university campus (4.3 %); use other (27.8 %); and do not involve in any activities when there is light out (36.9 %). At the time of data collection, 450 students (representing 70.0 % of the sampled students) indicated that there was no stand-by power generator in the hall of residence. Of the remaining 196 students that stated that there was a stand-by power generator in their hall of residence, 181 (92.3 %) indicated that the stand-by power generator was put to use only when the power from the electricity company of Ghana was out. Out of the 626 students that stated the number of times they experienced light off in a week, 462 (73.8 %) indicated that they experience erratic power supply one to four times in a week and 164 (26.2 %) experienced light off more than 4-times in a week.This study aimed to explore the possible link between the erratic electric power supply in Ghana and anxiety levels among tertiary students. It also aimed at contributing to the literature on mental health issues among African university students by exploring the proportion of students who experience electricity supply crisis-related anxiety disorders. This study also answers the research question about how erratic electricity supply to the university community may influence generalized anxiety disorder among University of Ghana students.Generally, it is believed that the recent electricity supply crisis in Ghana has affected the mental wellbeing of Ghanaians, including students at the tertiary level institutions. Students are believed to be particularly affected because that population is made up of a generation that have become increasingly accustomed to the use of modern technology, which in itself is highly dependent on the availability of uninterrupted power supply from the national grid.We found in this study that overall, nearly 26 % of the students that participated in the study indicated that they felt nervous, anxious or on edge “almost daily”. This suggests that the erratic power supply in the country influenced the mental wellbeing of more than a quarter of the tertiary level students. We also found that more than 30 % indicated having the same feeling on “several days” due to the erratic power supply situation in the country. Additionally, 23.1 % of the students in this study were found to have had severe generalized anxiety disorder as a result of the erratic power supply. This finding is higher than those classified in a sub-threshold with high severity of GAD symptoms that Kanuri et al.  found inSince our findings in this study suggests a link between the erratic electricity power supply and anxiety level among university students in Ghana, it could be due to a number of factors, including students’ inability to carry on with their routine academic activities such as conducting online search, completing class assignments and overall academic work that is increasingly becoming technology dependent in Ghana. The students’ anxiety level could also be influenced by the fact that the electricity disruption impacted their ability to prepare meals. This is because some students on Ghanaian university campuses tend to prepare their own meals in their halls of residence, unlike their counterparts in places like the U.S. where students on university campuses obtain their meals already prepared by vendors . TherefoAlthough in this study we found that female students had a slightly higher prevalence level of moderate anxiety, compared to their male counterparts, there was no such difference in the prevalence level in the severe anxiety category when both sexes were compared. The higher prevalence of moderate level of anxiety found in female students compared to their male counterparts in our study was somewhat similar to what other studies found , 22.Despite the fact that the electricity power supply company, the electricity company of Ghana (ECG), had made an attempt to publish a schedule of when and where there would be power outage for each community so that people can plan ahead or anticipate disruption, the students on the university campus were still found in this study to have experienced some amount of generalized anxiety disorder, especially among the undergraduate level students. In fact, we found that in all the undergraduate student class levels, including levels 100–400 (freshmen–seniors), there were self-reported moderate (18.3–24.8 %) and severe (16.5–27.4 %) prevalence levels of GAD.Although our overall finding of more than a quarter of students that felt nervous, anxious or on edge nearly every day due to the disrupted electricity supply seem consistent with the World Health Organization’s estimates that of any given population, about 25 % will suffer from a mental disorder, it is important to note that our study population lived in an environment that was characterised as a crisis moment of electric power supply. As discussed earlier, several factors contribute to individuals developing either episodic or chronic mental disorders and for that matter, the electricity supply crisis was found in this study to influence the university students’ feeling of GAD. This therefore goes to suggest that in spite of efforts by the power company to minimize any impact of the infrequent power supply to the Ghanaian population through the publication of outage schedule, the university students’ level of anxiety resulting from the outages was still apparent.This study on the mental health effect, especially on anxiety levels, influenced by erratic power supply has some local, national and global implications. First, it provides important opportunity for policy development and implementation that will address the potential for health related effects of poor electric power supply in Ghana and elsewhere in Africa. This is particularly relevant now because other African countries, including in South Africa, have recently begun electric power rationing and for that matter the health and mental wellbeing of their population will likely be affected by this systemic electric supply issue as it is in Ghana.The findings are also very important to the university administrators who now have the scientific research information to enable them to plan and put in place measures to minimize and/or address the mental health effect of the erratic electric power supply to the student population. This we believe can be done through evidence-based informed planning to enable them to institute screening, brief intervention and referral to treatment for those that may be impacted by the poor electric power supply.Further, our research is in line with one of the objectives of the World Health Organization’s “Mental health action plan: 2013–2020” that includes strengthening evidence and research on mental disorders, especially since there is dearth of research on mental disorders, including on students in low-middle income countries like Ghana .This novel study on the link between the disrupted power supply and anxiety level among students is not without some limitations. The first limitation of this study is that the GAD-7 scale used for this study does not conclusively confirm that respondents indeed has anxiety disorders since the GAD-7 provides only probable diagnoses that requires confirmation in a further evaluation by a clinician. Also, the GAD-7 measures only a specific mental disorder and for that matter, students who experienced other co-occurring mental disorders with symptoms similar to that of GAD may have been included in the overall prevalence of GAD in the student population. Additionally, since our study did not evaluate the link between students’ work load and anxiety levels, it is possible that other factors may have influenced students’ anxiety levels during the electric power outages but not necessarily the erratic power supply itself. Furthermore, the lack of information about students’ with pre-existing conditions of mental disorders such as depression or stress is a major limitation of this study.In spite of the limitations of this study however, it is important to have conducted the study in order to provide baseline information on the prevalence of GAD among college students in Ghana.Furthermore, additional research is needed to assess the true impact of the link between the poor power supply and anxiety levels among tertiary level students in Africa, especially since a greater understanding of this condition among tertiary level student population who are exposed to various levels of emotional stressors is needed.This exploratory study provided valuable information on the link between disrupted power supply at a national level and its impact on the health of the population, particularly for groups that are heavily reliant on constant electric power supply for their daily activities. In fact, the study underscores the point that even in resource-poor countries including Ghana, where it is often not expected for issues such as irregular electricity supply to have an impact on the mental well-being of the people, it may indeed have an influence on certain groups of the population, including students whose anxiety levels are now known to be associated with power supply crisis.


The paper presents a significant improvement to the implementation of the spectral relaxation method (SRM) for solving nonlinear partial differential equations that arise in the modelling of fluid flow problems. Previously the SRM utilized the spectral method to discretize derivatives in space and finite differences to discretize in time. In this work we seek to improve the performance of the SRM by applying the spectral method to discretize derivatives in both space and time variables. The new approach combines the relaxation scheme of the SRM, bivariate Lagrange interpolation as well as the Chebyshev spectral collocation method. The technique is tested on a system of four nonlinear partial differential equations that model unsteady three-dimensional magneto-hydrodynamic flow and mass transfer in a porous medium. Computed solutions are compared with previously published results obtained using the SRM, the spectral quasilinearization method and the Keller-box method. There is clear evidence that the new approach produces results that as good as, if not better than published results determined using the other methods. The main advantage of the new approach is that it offers better accuracy on coarser grids which significantly improves the computational speed of the method. The technique also leads to faster convergence to the required solution. This work describes a new approach to the solution of a system of four partial differential equations that model the flow of unsteady three-dimensional magneto-hydrodynamic flow and mass transfer in porous media. As reported in Hayat et al. , such eqA popular numerical method used by many researchers to solve unsteady boundary layer flow problems is the Keller-box method Ali et al. , b, Lok Both the original SRM and SQLM used in Motsa et al.  use finic the stretching parameter is a positive constant. M is the local Hartman number, Sc the Schmidt number, Pr the Prandtl number and We consider the unsteady and three-dimensional flow of a viscous fluid over a stretching surface investigated by Hayat et al. . The flur and x and t respectively. The derivative of nth order derivative with respect to T denotes matrix transpose. Collocating using Eqs.  for solving the system of nonlinear partial differential equations –3). App. App3). refethen  for \docmentclasspt{minima by Eqs.  respectiquations  are usedIn this section we present the numerical solutions of the three dimensional unsteady three dimensional magneto-hydrodynamic flow and mass transfer in a porous media obtained using the BI-SQLM algorithm. In our computations the As earlier mentioned, this problem has been solved before by Motsa et al.  using thThe grid independence test for the algorithm is shown in Table The residual error graphs of Eqs. –3) are  are 3) af and g even when fewer iterations are used. The observation that the residual error for the momentum and energy is small even for the 1st iteration is perhaps the most interesting finding of the study. This means that when using the proposed approach, the best possible results that can be achieved by the method can be obtained after using just one iteration. Further increase in the number of iterations doesn’t improve the accuracy of the solution. After one iteration of the momentum equations for f and g the energy and mass transfer equations reduce to linear homogeneous equations whose solution appears to be marginally influenced by variations in We observe that the residual error for the first iteration appears to be very small in Figs. The convergence graphs of Eqs. –3) are  are 3) aThe accuracy of the solutions for energy and mass transfer equations are not dependent on successive relaxation or iterations of the momentum equations since the convergence of the solutions doesn’t improve at all with an increase in the number of iterations. Hence, the results for In Table mentclass2pt{minimg and g when In Tables The method gives accurate results in the whole space and time domains The application of spectral collocation to both time and space derivatives ensures that the method performs significantly better than the SRM and the Keller-Box method in terms of computational time.The algorithm involves the usage of known formulas for discretization using Chebyshev spectral collocation.In future we intend to show that the technique can be extended to coupled non-linear systems in three-dimensions.The aim of this work was to describe the bivariate spectral relaxation method for systems of coupled partial differential equations. This technique extends the previous spectral relaxation method of Motsa et al.  to allow


Due to an expanding knowledge about the molecular diversity the disease Osteogenesis imperfecta (OI), formerly known to be a disorder of the collagen synthesis, changed to a group of disorders with a fragile skeleton as common symptom. Patients with OI type VI are clinically characterized by an increased amount of osteoid and a poor response to bisphosphonate treatment.In two boys with signs of OI we identified the disease causing mutation of OI VI . MutatioDue to the new understanding of the pathophysiology of OI VI we decided to target the osteoclasts directly using the Rankl-antibody Denosumab. This was the first use of Denosumab in children.With this change of therapy we were able to reduce bone resorption to the normal range .After two years of treatment both patients show an increase of bone mineral density of the lumbar spine with a z-score from – 2.4 to -2.0 and -4.3 to 2.5 respectively and an increase of projected vertebral area L2 – L4 [mm²] from 1670 to 2152 and from 1424 to 1528. No severe side effects were seen and the drop of serum calcium after the subcutaneous injection could be treated by oral calcium supplementation.Clinical observation and molecular analysis lead to a new understanding of OI VI and to a more specific therapeutic approach. The new therapy resulted in a better therapeutic effect and is a striking example of a fast transfer from basic research to therapeutic use.


The frequency of dental trauma in schools is secondary only to accidents at home. The aim of this study was to evaluate the knowledge of first aid in the avulsion of permanent teeth presented by Polish school nurses from different areas.2 tests with the level of statistical significance at p < 0.05.A cross-sectional study with the use of a structured self-administrative questionnaire was conducted in 2014 on school nurses working in randomly selected Polish provinces. The instrument consisted of demographic questions, questions referring to nurses’ experience and training in dental trauma and questions checking knowledge of first-aid in the avulsion of permanent teeth. The maximum number of points to be scored was eight. Data were analyzed with the Kruskal-Wallis, the Mann–Whitney U and Chip < 0.001). Being a witness to dental trauma (p = 0.0032) and working in schools with sports classes (p = 0.0423) were positive determinants of improved knowledge. Nurses from large agglomerations had significantly lower knowledge (p = 0.005). The main source of information for self-education was the Internet.The final sample consisted of 164 nurses of which 70.1 % had experience with dental injuries and 45.7 % witnessed a tooth avulsion in pupils. 10.4 % nurses participated in training courses concerning tooth avulsion and 67.1 % of them independently broadened their knowledge. The knowledge of the first-aid management of an avulsed tooth was moderate (4.72 ± 1.95 points). 78.1 % of nurses chose a correct definition of the term of ‘tooth avulsion’. Only 7.3 % of them were aware that the replantation could be conducted by any witness of an accident. Saline was most often chosen as a proper transport medium for an avulsed tooth (57.9 %), whereas 16.1 % of nurses indicated milk. 13.4 % of evaluated nurses showed readiness to conduct an immediate replantation. Most respondents preferred calling child’s parents and advising them to bring the child to a dentist (63.4 %). The main factor influencing nurses’ level of knowledge was self-education (The evaluated nurses were in need of education with regard to the management of dental trauma cases. The Internet should be used to deliver evidence-based knowledge to medical staff working at schools. Traumatic dental injuries (TDI) are very common in school-age children. Glendor  estimateAmong several kinds of TDI, special attention should be paid to avulsion injuries, i.e. a complete displacement of a tooth from its socket in the alveolar bone, because the chances for preservation of the tooth are highly dependent on proper action taken at the site of accident. For the permanent dentition, the most desirable action is an immediate replantation of an avulsed tooth into its socket, which may be performed by anybody, even the victim, during first 5 min following the accident. An avulsed tooth should not be stored dry for a long time because after 30–60 min the majority of periodontal ligament cells will become necrotic, which significantly reduces the prognosis of periodontal healing. If immediate replantation is not possible, to prevent dehydration, the tooth should be stored in a transport medium that is a physiological solution which closely replicates the oral environment, especially its pH and osmolality. The most suitable media, like the Hank’s Balanced Salt Solution (HBSS), are not readily available to the general public, therefore milk, coconut milk, soya milk, normal saline and even patient’s saliva may be used as a short-time storage medium needed to transport the avulsed tooth to a dentist. There are also general rules that have to be followed in case of dental avulsion to prevent crushing of periodontal ligament cells: (i) the tooth should be held by the crown to avoid the damage of periodontal ligament on the root surface, (ii) a dirty tooth should be gently rinsed with water or saline, disinfectants and scrubbing of the root are inadvisable, (iii) the victim should be referred to a dentist as soon as possible .In many cases the child’s accident would result in damages paid to injured children and their families by the founding bodies of educational institutions. The amount of such compensation may depend on the way in which first aid at the scene of the accident has been administered . UndoubtOnly a few studies assessing school nurses’ knowledge and attitudes of first aid of tooth injuries were conducted. They revealed the necessity of including dental trauma in the nurses’ education , 12. TheA descriptive cross-sectional study was conducted in the period from January to April 2014 under approval of the Bioethical Committee of the Medical University of Bialystok. Due to organizational reasons we chose a half of 16 Polish provinces using the Rand function from Microsoft Office Excel 2010. Then we searched the online database of the Central Statistical Office of Poland [A structured self-administrative questionnaire adopted in this survey had been previously used in the study of Baginska and Wilczynska . Nurses To assess nurses’ knowledge, the answers to the questions from section II were scored with points. Questions referring to: a definition of tooth replantation, a person who should conduct this procedure, the best time for tooth replantation and the way of holding and cleaning an avulsed tooth had a key answer and could be scored with 1 or 0 point. The only multiple-response question concerned the storage of the tooth until replantation. One point was given exclusively for an answer containing at least one recommended medium  without the indication of improper ways of storage of an avulsed tooth . If a surveyed nurse indicated even one improper way of tooth transport she received 0 points for that question. The possible score for the question “What would be your action in case of the necessity to provide first aid to a child with dental avulsion?” varied from 0 to 2 points. We gave 2 points for the answer: “immediate placement of a tooth into its socket” as it was the most proper behaviour, and 1 point was always given if the respondent chose the answer “call a dentist and follow her/his instructions”. In case of the answer “transport of the child to the nearest dentist” or “calling his/her parents with the instruction to transport of the child to the nearest dentist” the score was dependent on the answer to the question concerning the storage medium, i.e. 1 point if the nurse knew the proper storage medium and 0 points if an incorrect medium was indicated. The maximum number of points to be scored by any respondent was eight.2 test was used to determine variables connected with the participation in training courses, and the self-education in the surveyed population. The level of statistical significance was established at p < 0.05.The Statistica 10.0 software  was used for the calculations. Descriptive statistics were used to describe the study population. Means, median (Me), lower and upper quartile  of number of points scored by nurses were calculated with regard to their education level, location and type of class in school, having experience in dental trauma, training courses and self-education in dental trauma. The normality of distribution was verified using the Kolmogorov-Smirnov test with the Lilliefors correction and the Shapiro-Wilk test. The normality of distribution of analysed quantitative variables was not found. On this basis, non-parametric test for hypothesis testing were used. Kruskal-Wallis, the Spearman’s rank correlation coefficient and the Mann–Whitney U tests were used to assess factors influencing the level of knowledge of respondents. The ChiOne-hundred and sixty-four questionnaires with data suitable for statistical analysis were returned. Another returned questionnaire with only the demographic part filled in was not included in the analysis. The overall response rate was 49.25 %. Based on the following assumptions: 333 school nurses invited to the study, 70 % of them having experience with dental trauma, the maximum error of 5 % and the confidence level of 95 %, we established the minimum number of respondents needed for statistical analysis to be exactly 164 subjects.The demographic background of the surveyed population is shown in Table Table Table p < 0.001, Mann–Whitney U test). Statistical analysis also showed that the knowledge of school nurses depended on their place of work. The individuals working in large agglomerations (over 100 000 inhabitants) scored fewer points than the nurses from towns and villages . Being a witness to dental trauma  and the work in schools with sports classes  also positively influenced nurses’ knowledge. The individuals who encountered a dental trauma showed interest in training courses and self-education .Table The outcome of permanent tooth’s avulsion depends, among other factors, on the action taken during the first minutes after trauma . The stuOur study did not reveal any influence of respondents’ education level on their knowledge of first aid in dental avulsion. It may result from the low percentage of subjects who declared having a higher education. The majority of Polish school nurses have only secondary or post-secondary nursing vocational education, and in our study they constituted three-quarters of the sample. Despite the fact that Poland offers the full range of higher education in nursing  the percOur study revealed that a strong determinant of school nurses’ knowledge was the location of the schools, and so far this aspect has not been raised. Some inequalities in the access to the healthcare for pupils from rural settings were previously observed in Poland due to the lack of a medical room in a considerable percentage of rural schools, the nurse’s care for several distant schools and frequently exceeded standards concerning the number of pupils per one school nurse . TherefoOur study showed that school nurses had to pursue self-education on dental trauma and we found that it was a very effective method to broaden the knowledge. It is characteristic that such individuals who encountered a tooth injury showed an increase in interest in the problem of dental injuries. Consequently, the nurses who had experience with tooth avulsion better answered the questions concerning the management of such injury. It is noteworthy that self-education concerning first aid to individuals having a tooth injury is difficult because many first-aid handbooks do not include such information within an appropriate scope . CurrentHowever, there are some inadequacies of self-education. Skills and attitudes are equally important to the knowledge in the daily practice of school nurses. Elgie at al.  found thThe response rate not exceeding 50 % should be considered as a limitation of the present study. However, in the mail survey on public nurses in Norway regarding their attitudes towards the promotion of oral health, the response rate was even lower than in our survey . ProbablThe conducted survey revealed that the nurses’ level of knowledge of permanent tooth avulsion management was moderate and nurses working in large agglomerations presented the lowest knowledge. Due to the lack of training courses, some nurses obtained the required knowledge by self-education, mainly via the Internet. This channel maybe used to increase the public awareness of dental injuries and to deliver the evidence-based knowledge on dental trauma to non-dental medical professionals, including school nurses.


We investigate the uncertainty in the strong coupling  There has been a continual improvement in the precision and in the variety of the data for deep-inelastic and related hard-scattering processes. Noteworthy additions in the years since the MSTW2008 analysis  have beeWe refer to Fig. mentclass2pt{minimIt is sometimes debated whether one should attempt to extract the value of ge value . Howevermentclass2pt{minimHowever, ultimately for the use of PDF sets by external users it is preferable to present the sets at common (and hence ‘rounded’) values of le as in  we hencepegasus [hoppet [Before we continue we should specify how the running of  pegasus  and hopp [hoppet , and it mentclass2pt{minimW and Z production by the CDF and D0 collaborations and, finally, nine data sets from the ATLAS, CMS and LHCb collaborations at the LHC. In addition, the NLO fit also used jet data from the ATLAS, CMS and H1 and ZEUS collaborations, which were not used at NNLO because it was judged that at present there is not sufficient knowledge of the full jet NNLO cross section; jet production at the Tevatron, on the other hand, is much closer to threshold than at the LHC, so the threshold approximation to the full NNLO calculation is much more likely to provide a reliable estimate in this case. The goodness-of-fit quantity, The NNLO MMHT2014 global analysis [n by n as the difference from the value at the global minimum, In the NNLO global fit of , let us entclass1pt{minimaWe repeat this exercise at NLO. Then the profiles will satisfy The fixed-target structure function data in the first 14 plots in Figs. The NNLO corrections to the structure functions are positive and speed up the evolution, leading to smaller optimum values of The recent combined H1 and ZEUS structure function data from HERA prefer a value of ig. 5 of . Note, hαs(MZ2)  . This wipp Drell–Yan cross sections data, are clearly more quadratic at NNLO than at NLO, with minima closer to the best-fit values. This indicates a strong preference for the NNLO description, which is not so apparent if only the global best-fit values pd / pp Drell–Yan production are a ratio of cross sections, the sensitivity to the value of The longitudinal structure function FL , 16 are The Tevatron data, as well as the ATLAS Judging from the values of There is a particularly strong, but also complicated, relationship between the value of In the global fits the theory calculation of The NNLO correction to the cross section in the pole mass scheme is moderate, but large compared to the most precise data, and hence the NNLO cross section tends to be too high. This leads to the opposite pulls to those at NLO, i.e., NNLO prefers First we investigate the quality of the global fit as a function of both The equivalent plots to Fig. At NNLO it is again clear that higher values of entclass1pt{minimaHence, the overall conclusion is that some added freedom in First, recall that in the MMHT2014 analysis [In order to determine the uncertainty on  of Ref. ; that ismentclasspt{minimaThe dominant constraint on There are a number of other data sets which give almost as strong constraints. For instance, at NLO in the downwards direction we find that SLAC deuterium data give either to ignore the possible effects of alternative treatments of the mass or to warrant a completely thorough investigation at this stage.Two of the four dominant constraints nominally come from Each of these values of When considering the uncertainty on the prediction for a physical quantity we should include the uncertainty on In the MSTW study  of the PSince the MSTW study  was undenvectors . In shorIn Sect. x for It is informative to see the changes in the PDFs obtained in global fits for fixed values of x. This is the dominant constraint on the gluon, and a smaller low x gluon leads to a larger high-x gluon (and vice versa) due to the momentum sum rule. The u and d PDFs have the opposite trend as x values this is a marginal effect, due to the interplay of a variety of competing elements. At high x the decreasing quark distribution with increasing x. The insensitivity of the strange-quark PDF to variations of x is partly just due to the relative insensitivity of all low-x quarks, but is also partially explained by the comments in the previous section about the MMHT analysis [As expected, the gluon distribution for analysis  of dimuox range about x, and is relatively insensitive to the parameters of the starting distributions.In Fig. W and Z boson, Higgs boson via gluon–gluon fusion and top-quark pair production.In this section we show uncertainties for cross sections at the Tevatron, and for 7 and We calculate the PDF and W, Z and Higgs production we use the code provided by Stirling, based on the calculation in [To calculate the cross section we use the same procedure as was used in . That isation in –21, and ation in . Here ouW and Z production cross sections. The results at NNLO are shown in Table x where PDF uncertainties increase. The x values. As already mentioned the Tevatron cross sections are more sensitive to the high-x quarks, which decrease with increasing x that the distributions increase with x and the increase of the cross section with We begin with the predictions for the x, as it is the approximate pivot point of the PDFs. Hence, there is only a small change in cross section due to changes in the PDFs with x quarks that occurs for W, Z production.In Table x value probed being x probed means that most contribution is below the pivot point and there is some anti-correlation between the direct x PDFs, the gluon in this case. At the Tevatron and for 7 TeV at the LHC the At the LHC the dominant production at higher energies (and with a proton–proton rather than proton–antiproton collider) is gluon–gluon fusion, with the central x range probed, i.e. x gluon, while at the LHC the PDF uncertainty is much reduced due to the smaller x probed, and is similar to the In Table We also repeat the study at NLO for the Higgs cross section. The results are shown in Tables The PDFs determined from global fits to deep-inelastic and related hard-scattering data are highly correlated to the value of ined. In  we produented in , but als191 (NLO) and \doc3 (NNLO) . HoweverNNLO) in . We findfound at  and are found at . They shW, Z, top-quark pairs and Higgs bosons at the Tevatron and LHC. For W and Z production, where the LO subprocess is In order to calculate the PDFeered in  of treatshown in , provideIn addition, we note that for any particular process the details of the uncertainty can now be explicitly calculated in a straightforward way using the PDFs we have provided in this paper, together with the procedure for combining PDF and Moreover, it is also straightforward to apply the procedure to determine the uncertainties coming from combinations of PDF sets obtained by global analyses of different groups. Using techniques given in –31 it is


Rhinomanometry can still be considered as the standard technique for the objective assessment of the ventilatory function of the nose. Reliable technical requirements are given by fast digital sensors and modern information technology. However, the xyimaging of the pressure-flow relation typically shows loops as a sign of hysteresis, with the need for resolution of the breath in four phases. The three pillars of 4-phase rhinomanometry (4PR) are the replacement of estimations by measurements, the introduction of parameters related to the subjective sensing of obstruction, and the graphical information regarding the disturbed function of the nasal valve. In a meta-analysis of 36,563 clinical measurements, we analyze the errors of the “classic” parameters (flow in 150 Pa) and reject the further use of these parameters as obsolete, because they correspond to an inaccurate estimation rather than proper measurement. In a pre-study of 1580 measurements, the logarithmic effective resistance (Reff) was found to have the highest correlation with values obtained from a visual analog scale. Next, we classify the inspiratory effective resistance in 20,069 measurements without treatment and 16,494 measurements after decongestion with xylometazoline 0.1 % spray in 20 % percentiles. The gradation of obstruction delivers not only “normal” values but also indications for the severity of the obstruction in adult Caucasian noses. Adoption of the distribution for the growing nose and analysis of the total nasal resistance is addressed, and typical findings of nasal valve phenomena are outlined. The introduction of computer-aided rhinomanometry and the replacement of previous graphic methods around 1980  can be cIn 1994, during the conference of the European Rhinologic Society in Copenhagen, Vogt and Hoffrichter  proposedThe three pillars of four-phase-rhinomanometry are: the replacement of estimations by measurements, the introduction of parameters related to the subjective sensing of obstruction, and the graphical information regarding the disturbed function of the nasal valve.The diagnostic power and accuracy in “classic” rhinomanometry of measured flow at a differential pressure of 150 Pa and its incorrect derivation “Resistance at 150 Pa”The distribution of the parameters effective resistance and vertex resistance and their logarithmic derivations within a population of healthy and diseased noses before and after decongestion by xylometazoline, the subsequent classification of clinical results, and their correlation between sensation and objective obstruction.Given the ongoing discussion about the differences and the clinical usefulness of “classic” rhinomanometry and 4PR, the following issues of clinical interest and high importance in experimental studies about the respiratory function of the nose have been investigated:The rhinomanometric databases of five different German ENT hospitals that have been using 4PR for more than 5 years are analyzed in this study. Three departments are dealing with general otorhinolaryngology and two hospitals are specialized in facial-plastic surgery. The age range of patients was 14–82 years. In 20,069 untreated nasal sides, active anterior rhinomanometry was carried out. A total of 16,494 measurements were subsequently followed by a decongestion test with xylometazoline 0.1 % spray and a second measurement 10 min later.The calibration of the device was controlled over predetermined distances; the calibration of all instruments was correct before the beginning and after the end of the studies.For the coupling of the pressure tube to the nose, the “tape method” was exclusively applied. The use of any prefabricated coupling element is forbidden in the participating departments. The elastic tape Microfoam (3 M) was used. Anesthesiologic masks of different sizes  were chosen. The extranasal “dead space” did not exceed 0.15 L including connection pieces and filter housing.All measurements were carried out after adaptation of the patient to room temperature, at rest and in an upright sitting position.All protocols were reviewed with regard to technical errors. A total of 157 measurements obtained from non-Caucasian noses or children were excluded from the study. All measurements were carried out using the 4PR rhinomanometer models HRR3 or 4RHINO  with software version 3.57, 4.31, or 5.01. The software of this system is Windows-based and the format of the data stored in the databases has been identical since 1999. The following details are important for providing exact measurements and reproducible results.The measurement results are stored as an average of 3–5 breathing cycles with 2000 data for flow and differential pressure according to the recommendations of the ISOANA 1984. The averaging procedure by splining was described previously by Vogt and Wernecke [The nasal flow at 150 Pa differential pressure during the four phases of the nasal breathing cycle is marked as intersection points in Fig. Vertex resistance (VR) Fig.  and logaearchers , 8, mustEffective resistance (Reff) Fig.  and logaEvaluated parametersThe descriptive statistics of the non-classified material and the after classification are summarized in Table In this part of the study, 20,069 measurements before any treatment and 16,494 measurements 10 min after decongestion with 0.1 % xylometazoline spray were included. As mentioned frequently in earlier publications, some patients cannot reach the pressure level of 150 Pa or higher [Within the remaining cohort the means were calculated for the flow in 150 Pa Fig. .Fig. 4Stp < 0.0001. The descriptive statistics of the flow differences between phases 1 and 2 and between phases 3 and 4 (in percent) are shown in Table The order phase 1 > phase 2 > phase 3 < phase 4 is clearly visible and appears in the same order in all subgroups investigated previously. All differences are significant at a probability level The histograms of the differences between phases 1–2 and 3–4 Fig.  imply thIn summary, the statistical facts presented here, in addition to numerous single observations in typical pathologic cases, confirm the necessity of resolution of the nasal breathing curve in four phases as being of clinical importance.Besides the mandatory numeric information, the visual information is also missing, which is obtained when the elastic properties and Bernoulli phenomena release the so-called valve effects, leading the surgeon to a more precise indication for surgical intervention to improve the nasal obstruction . Two typThe observed differences between phases 1/2 and 3/4 show clearly that the hysteresis of the curves, which can be seen only by 4PR, is not a negligible physiologic phenomenon. The experiments of Gross and Peters  showed cIn summary and in conclusion of this part of our analysis, we reject strongly the statement and the conclusions of Wong and Eccles , deducedThe nasal air stream is to a great extent an “unsteady” air stream by definition, which is permanently and quickly changing its velocity and direction within an irregular structure. It is always in part turbulent and laminar, which can be easily demonstrated by computational fluid dynamics.If the shape of the nasal channel corresponds to a “diaphragm” or “bore” or “hole,” the air flow is preferably turbulent; if the shape of a nearly completely obstructed nose is more similar to a tube, where the length exceeds 20 times the diameter, the air stream becomes laminar.Bernoulli effects play an important role in affecting the desired closure of the nose while sniffing or sucking the nasal mucus backwards. These effects are not reproducible and depend also on minor variations of the nasal anatomy, the elastic properties of the nasal wall, and the acceleration of the inspiratory air flow. They are also present at the conscious release of the closure.In the literature over many years, in theoretical considerations of the nasal air stream, the terms “laminar” and “turbulent” air stream are found, as well as non-successful attempts to find a mathematical equation describing the relation between pressure and flow of the nasal air stream. Under the auspices of contemporary research in fluid dynamics, we know that:Parameters should describe the relation between pressure and flow or, furthermore, the energetics of nasal breathing, without any regard to the shape of the nasal breathing wave.Parameters must be measurable in any case. Estimations have to be replaced by measurements whenever possible.Parameters should be statistically related to the sensing of obstruction, i.e., the subjective feeling of the patient.Against this background, parameters describing the nasal air stream should have the following properties:These criteria are met for the VR as the only acceptable point-measurement within the breathing cycle and for the Reff, which is in fact the summation of a series of rapid measurements in a millisecond distance, computed for the inspiratory or expiratory part or for the entire breath. The resistance as a relation between pressure and flow is no longer calculated by a division of points but by a “division of areas”. VR and Reff are highly correlated to each other and show only very low differences in a pooled cluster. However, they do differ when the ascending nasal air stream releases the Bernoulli effect at the nasal valve and the air channel is narrowing. In this case, the resistance during the descending inspiratory part (phase 2) is higher, and the Reff exceeds the value of the VR Fig. .Fig. 7TyIt was shown as early as 2003  that theEvery sensory message, the sensation of force or power, which is necessary for the work of nasal breathing, follows the well-known logarithmic scale of Weber–Fechner, which states that subjective sensation is proportional to the logarithm of the stimulus intensity. Relating the measured degree of nasal obstruction to the sensation of the work of breathing as given on a logarithmic visual analog scale (VAS) is much more informative after using logarithmic scales for both parameters (see below).There are two reasons to use VR and Reff as diagnostic parameters after logarithmic transformation:Under these preconditions, we proposed a classification for nasal obstruction using logarithmic parameters after multiplication of the measured value by 10, which was proposed as more practicable in daily clinical work  through In a preceding study, the same parameters applied in this meta-analysis were correlated with results obtained from a VAS scale, which has been implemented in the applied software for 15 years. The values are generated by shifting a “button” from the middle to the right or left side based on the actual feel of obstruction. In the case of a repeated measurement after application of nasal spray, the patient adjusts the button after the second measurement.In this study, a classification of the subjective values was obtained by setting up 20 % percentiles of the population Table .Table 5CThe histograms shown in Fig. p < 0.0001).The correlation analysis (cf. Pearson’s correlation) of the data yields the results from one subjective and various objective parameters Table . All of A comparison of the statistical distribution of the values before and after logarithmic transformation Fig.  shows clFrom Table The clinical results of 20,069 untreated nasal sides and 16,494 measurements after a decongestion test with xylometazoline based on 20 % percentiles for the LER in inspiration confirmed these findings Table  and are The International Standardization Committee for the Objective Assessment of the Upper Airway was founded in Brussels in 1984. It published two important recommendations , 12 in tAccepting these facts, the causes of differences in flow measurements between the breathing phases are explainable, and the statistics herein show the extent of false or missing data. In addition, the calculation of linear resistance by the flow values at a single point is physical and mathematical nonsense, and the information about the flow at a given pressure delivers only an estimation of limited value for the critical analysis of nasal breathing, which may be in many cases erroneous. The calculation of the total nasal resistance can be better carried out with the correct parameters VR and Reff. The recent clinical review by Clement et al.  refers oThe relation between objective measurements and the feeling of obstruction has been repeatedly discussed during recent years. Nearly all publications refer only to classic rhinomanometry and have found no or only weak correlations –17. The Recommendations for the clinical classification of rhinomanometric measurements have been given previously by Bachmann  and VogtThe parameters Reff and VR and their logarithmic derivations have been proved to be capable of measuring the degree of obstruction of the nasal airway. The classification, which as of now is valid for adult Caucasian noses, will be adapted for other races and in a dynamic way for the growing nose in childhood. The investigated parameters can be implemented in any system of computerized rhinomanometry. This approach should replace inaccurate methods of estimation as used in so-called classic rhinomanometry and be exclusively applied in pharmacologic clinical studies. In a subsequent report, we will analyze the connotations of 4PR for measurements of total nasal resistance.


Fall detection is a major challenge in the public healthcare domain, especially for the elderly as the decline of their physical fitness, and timely and reliable surveillance is necessary to mitigate the negative effects of falls. This paper develops a novel fall detection system based on a wearable device. The system monitors the movements of human body, recognizes a fall from normal daily activities by an effective quaternion algorithm, and automatically sends request for help to the caregivers with the patient's location. Falls of the elderly always lead to serious health issues as the decline of their physical fitness . FracturProgress of technology brings more possibilities to help us protect the elderly. Low power consumption components make it possible to realize wearable monitoring device. MEMS  sensors have simplified the design and implementation of sensor system. Location based service (LBS) makes it more convenient to locate the elderly in health monitoring. Beside these, mobile computing makes remote health monitoring easier to realize.Several kinds of fall detection methods have been developed or applied in our life . One of Motion sensor-based method is also commonly used. Accelerometer and gyroscope could provide linear and angular motion information directly. Sensor measurements or their proper fusion could be used to distinguish a real fall. There are several kinds of detection methods which differ in constitution of motion sensors and detection algorithms. The first kind of detection method is using an accelerometer. A single triaxial accelerometer can provide object's accelerations in three directions which include the influence of gravity. A coordinate will be built when the accelerometer is fixed on human's body. The influence of gravity or dynamic acceleration is available by using a low pass filter or a high pass filter . Some kiBut, in fact, using more sensors means more power consumption, and it is a challenge to design a proper algorithm to fuse different kinds of sensors. A single triaxial accelerometer is quite enough for human fall detection as sufficient information could be extracted from its measurements. Besides this, the accelerometer coordinate does not have to be fixed if only the magnitude of sum vector is needed , and thaThe architecture of the developed system is described in Choice of recognition feature has decisive significance to successful fall detection. Information like linear movements  and angular movements  could be obtained directly or indirectly. Beside these, frequency domain parameters could be extracted from basic sensor measurements by techniques such as FFT and wavelet , 12. ForFall detection algorithm design is based on the choice of recognition features. According to the recognition feature, fall detection algorithms are classified as threshold based and machine learning based. For threshold based method, threshold of recognition feature is set by the designer before application which makes the algorithm have rapid response and less resource consumption . But thea which has magnitude asax, ay, and az present accelerometer measurements of three axes. The system uses the sum acceleration as the first step to distinguish high intensity movements from others. But normal motions such as jumping or sitting also produce peak values, which mean that additional detection features are required.Algorithm used in this fall alarm system is based on thresholds of sum acceleration and rotation angle information. When a real fall happens, collision between human's body and ground will produce obvious peak value at the sum acceleration The second feature used here is an angle calculated based on acceleration measurements. As human's motion has low acceleration, it is feasible to get gravity component in each axis by using a low pass filter. If gravity components could be separated before and after human's fall, then it is possible to calculate the rotation angle of accelerometer coordinate in 3D space, which is also equivalent to the rotation angle of gravity vector relative to fixed coordinate. Coordinate constructed by the accelerometer and the gravity vector is shown in Quaternion is an effective tool to describe rotation movement in human's gait change which also includes falling . A quateQ‖ = 1 can be described asUnit quaternion which has magnitude ‖Q equals θ. The rotation axis is orthogonal to the rotation plane and its direction is in accordance with right hand screw rule. qx, qy, and qz are three components of the unit vector which describes the orientation of the quaternion at the fixed coordinate.As shown in g which could be described as a quaterniongx, gy, and gz are three components of g which has quaternion magnitude asBesides rotation movement, quaternion can also describe a vector in 3D space, such as the gravity vector Q is used to describe human's falling movement, which can also be divided into three rotation quaternions Q1, Q2, and Q3 to simplify the calculation as shown in A unit quaternion With the help of gravity vector information before and after human's falling movement as shown in Q1 could be expressed asQ2 can be calculated asQuaternion Q3 isQuaternion Q. Quaternion algebra is normally implemented based on basic matrix algebra [Then the rotation of the fall movement can be expressed by quaternion multiplication as algebra . QuaternQ1, Q2, and Q3 are all available based on gravity information before and after the falling movement. At last, it is possible to get four elements of quaternion Q by the equation above and the rotation angle θ could be calculated asThe whole rotation quaternion can also be decomposed asθ will approach 90° which is also a character different from most normal activities. So it could be used as the second detection feature beside sum acceleration.When an object is falling, magnitude of The flow chart of the proposed algorithm is depicted in gbefore while the elderly is standing still. There is no special requirement of the device orientation but only keep stationary during the wear. athreshold means the threshold of sum acceleration magnitude and tthreshold means the threshold of oscillation time duration after the break of athreshold.The wearable device will be mounted on human's waist at first to reflect the motion of human body closely , and thea| will be calculated. When a real fall happens, sum acceleration will reach peak value of |a| ≥ athreshold. In a real falling, the fluctuation of acceleration will stop in time duration tthreshold and then the sum acceleration is |a| ≈ g as the elderly will lie on the ground. Then the acceleration a is recorded as gafter. Quaternion rotation θ will be calculated based on information gbefore and gafter. At last, the system will consider it as a fall if the rotation angle |θ| ≈ 90°.When measurements in three different axes have been acquired, the sum acceleration |ADI's digital triaxial accelerometer ADXL345 is the motion sensor used in this system. The GPS service and GSM communication function are integrated in SIMCom's SIM908 module. TI's 16 bits MCU MSP430F1611 is used to control the whole system and imply the detection algorithm .The measurement range of accelerometer could be set at ±2 g, ±4 g, ±8 g, or ±16 g, and the maximal sampling rate is 3.2 kHz. As human's activities are normally at low frequency bands , 100 Hz SIM908 can offer GPS and GSM service on serial port communication with MCU, and it can also work in low power mode.Each hardware component of the wearable device is working under low voltage and the detection algorithm does not need complex calculation resource, so the power consumption of the whole device is quite low. A 1200 mAh, 3.7 V polymer lithium battery is quite enough to provide the need of the wearable device for a couple of days.Hardware structure of the detection device is shown in The software design of the system can be divided into two parts. One of them is the software design in wearable device, and the other is in the caregiver's handset.Flow diagram of the wearable device software is shown in gbefore would be extracted from acceleration measurements by using a low pass filter when the elderly is standing. After that, the fall detection algorithm will be applied. If a fall has been detected, the wearable device will locate the user and send alarm short message to caregivers immediately. Then the device will remind the elderly through vibration. If the user withdraws the alarm by pressing a button manually, the device will get back to fall detection state and a short message will be sent to inform the caregivers.After initialization of the system, There is a URL  which links to a web map in the alarm short message. The fall location information will be highlighted on a web map when the caregiver opens this link.System test of the fall detection system has been conducted based on the system design described above.The sampling rate of accelerometer is set at 100 Hz and the measurement range is ±16 g with a maximum precision of 4 mg. MCU will read raw measurements from sensor's inner FIFO and apply the detection algorithm.athreshold and tthreshold are set as 2 g and 2 s, respectively. In order to get g when standing and lying after the fall, sum acceleration a which has magnitude between (1 − 0.3) g and (1 + 0.3) g will be considered as gbefore and gafter. Considering that the tilt of the ground or the lying posture of the elderly may affect the rotation angle, rotation angle θ between (90 − 30)° and (90 + 30)° will infer that the elderly has fallen.The test objects are three different volunteers at the ages of 23, 42, and 60, respectively. Based on analysis of these volunteers' experiment data, System test contains five kinds of activities of daily living  and four kinds of fallings .Each kind of motion has been repeated 20 times on each volunteer, and the detection results of the proposed algorithm and an acceleration threshold based algorithm  are listThe sensitivity and specificity , 22 of tAlarm receiving function on caregiver's handset has also been tested. An alarm SMS (short message service) containing a map URL has been received by the handset as shown in This paper developed a fall detection system based on a single triaxial accelerometer based wearable device. There is no special requirement of the device's mounting orientation because the algorithm does not claim the axes of accelerometer to be fixed strictly. The system has low power consumed hardware design and highly efficient algorithm which could extend the service time of the wearable device. Both the hardware and software designs are suitable for wearable and outdoor application.athreshold is quite important to distinguish falling from heavily lying activity. Sufficient sample number collected from subjects with different age and gender will improve the reliability and robustness of the threshold. Beside these, technologies such as SVM and neural network are considerable to seek out a proper classification method based on the features used in this system.As normal activity of resting also has similar rotation as falling, it may trigger fall alarm when the body hits ground heavily. So the choice of


Moreover, for a prescribed spatial covariance function we explore the differences in behaviour that can emerge when the underlying stationary distribution is changed from Gaussian to non-Gaussian. For travelling front solutions, in a system with exponentially decaying spatial interactions, we make use of an interface approach to calculate the instantaneous wave speed analytically as a series expansion in the noise strength. From this we find that, for weak noise, the spatially averaged speed depends only on the choice of covariance function and not on the shape of the stationary distribution. For a system with a Mexican-hat spatial connectivity we further find that noise can induce localised bump solutions, and using an interface stability argument show that there can be multiple stable solution branches.The original neural field model of Wilson and Cowan is often interpreted as the averaged behaviour of a network of switch like neural elements with a distribution of switch thresholds, giving rise to the classic sigmoidal population firing-rate function so prevalent in large scale neuronal modelling. In this paper we explore the effects of such  The study of waves, bumps and patterns in models of Wilson–Cowan type  is now aH is a Heaviside step function with threshold h. If we now associate a threshold ϕ is a probability distribution, this relationship immediately implies a monotonically increasing firing-rate function. Given a realisation of the thresholds t, it is of interest to ask how the spatial covariance structure of these random thresholds affects network dynamics. This is precisely the question we wish to address in this paper for continuum models of Wilson–Cowan type, in which the random firing threshold is now described as spatially continuous quenched disorder. Although we will restrict our attention to a Gaussian covariance function, we shall consider a broad class of stationary distributions, and present practical techniques from applied mathematics and statistics for working with non-Gaussian distributions. Moreover, by working with the Heaviside choice, as in . As it stands the model given by  κ, while Fig. For a symmetric choice of synaptic kernel al model  with a centclass1pt{minimamentclasspt{minimaof Amari  with theribed in , 35. To ussed in ): 21\docc takes the compact form m when We can also perturbatively calculate the effects of threshold disorder on the speed of a travelling front. Substituting  into 2121 and tac̅ as a function of ϵ for a Gaussian distribution of threshold values, as well as results from directly averaging realisations of  translation symmetry of the system, as described in [Neural fields of Amari type are known to support spatially localised stationary bump patterns when the anatomical connectivity function has a Mexican-hat shape. In a one dimensional spatial model, and in the absence of noise, it is known that pairs of bumps exist for some sufficiently low value of a constant threshold and that only the wider of the two is stable . For ranribed in  for neurA one-bump solution 2. Using  a one-buind from  27\documπ. Suppose the maximum is at 0 and a we require ϵ from zero breaks the translational invariance of the system and we obtain 4 bumps for We first consider a simple form of heterogeneity to present the ideas, and then move to more general heterogeneity. Suppose We keep given by . This wiTypical results for a Gaussian threshold are depicted in Fig. ϵ. While the number of solutions exhibits an increasing trend, the number of stable solutions decreases, leading to an overall decrease in the fraction of stable solutions. When lowering the correlation length five times . In Fig. mes Fig. , we obseϵ and the proportion which are stable. For ϵ increases two branches of solutions emerge from the solutions in the homogeneous case, which widen for larger values of ϵ. Note that as in the homogeneous case, only large-width bumps are stable. A more detailed view on bump solutions with a Gaussian threshold is presented in Fig. When ϵ increases, with the stable solutions confined to the upper branch. In contrast to the Gaussian case in Fig. Using the shifted exponential distribution for the threshold we obtain the results plotted in Fig. We know that for a Heaviside firing rate, Mexican-hat connectivity, and a constant firing threshold, multibump solutions cannot exist . Howevertates of  are showhreshold –42, or whreshold . Fig. 18In this paper we have explored the role of threshold noise on travelling fronts and bumps in a simple neural field model with a Heaviside nonlinearity. For a frozen form of disorder and a given realisation of a spatial threshold the standard rules of calculus apply and we have exploited the interface approach of Amari to obtain exact results about solution properties for both existence and stability. The theory that we have developed is not restricted to any special choice of distribution for describing the threshold noise, apart from that sample trajectories be differentiable in the mean square sense. It is worth noting that the stochastic threshold model presented here is formally equivalent to already published stochastic nonlinear integro-differential equations with constant threshold –14 when see e.g. ) and henTheoretical predictions have been shown to be in excellent agreement with numerical simulations of both Gaussian and non-Gaussian threshold models. As such we have a viable mathematically tractable model of a noisy neural tissue that would be of interest to explore in a variety of more neurobiologically relevant scenarios. For example, temporal correlations in excitability of neural tissue would be expected to strongly affect wave propagation and could be easily modelled with an appropriate choice for dynamics  with theroach in  and moreroach in  for underoach in  and an iroach in . These a


The number of clusters in a cluster randomized trial is often low. It is therefore likely random assignment of clusters to treatment conditions results in covariate imbalance. There are no studies that quantify the consequences of covariate imbalance in cluster randomized trials on parameter and standard error bias and on power to detect treatment effects.The consequences of covariance imbalance in unadjusted and adjusted linear mixed models are investigated by means of a simulation study. The factors in this study are the degree of imbalance, the covariate effect size, the cluster size and the intraclass correlation coefficient. The covariate is binary and measured at the cluster level; the outcome is continuous and measured at the individual level.The results show covariate imbalance results in negligible parameter bias and small standard error bias in adjusted linear mixed models. Ignoring the possibility of covariate imbalance while calculating the sample size at the cluster level may result in a loss in power of at most 25 % in the adjusted linear mixed model. The results are more severe for the unadjusted linear mixed model: parameter biases up to 100 % and standard error biases up to 200 % may be observed. Power levels based on the unadjusted linear mixed model are often too low. The consequences are most severe for large clusters and/or small intraclass correlation coefficients since then the required number of clusters to achieve a desired power level is smallest.The possibility of covariate imbalance should be taken into account while calculating the sample size of a cluster randomized trial. Otherwise more sophisticated methods to randomize clusters to treatments should be used, such as stratification or balance algorithms. All relevant covariates should be carefully identified, be actually measured and included in the statistical model to avoid severe levels of parameter and standard error bias and insufficient power levels. Randomized controlled trials are considered the gold standard for evaluating the effect of a new treatment relative to an old treatment, a placebo or no treatment at all. A necessary (but not sufficient) condition for the estimate of the treatment effect to be unbiased is that subjects in a given treatment group are not contaminated by those in another. This condition is often not fulfilled in trials that are offered in naturally existing groups, such as schools, general practices or communities, especially so when the treatments rely on interpersonal communication in risk reduction sessions and peer pressure groups . For thiThe number of clusters in a cluster randomized trial is often low . As a coIn practice it often occurs not all relevant covariates are known and/or not all of them have been measured. As a consequence, type I or type II error rates may be inflated. The degree of inflation depends on the precision of the treatment effect estimator, which is affected by the strength of the covariate effect and degree of covariate imbalance. A recent study quantified the effect of covariate imbalance on bias and precision of the treatment effect estimator and the power of the test on treatment effect for simple randomized trials . With suThe number of clusters in a cluster randomized trial is typically much lower than the number of subjects in a simple randomized trial, hence covariance imbalance is more likely to occur in cluster randomized trials than in simple randomized trials. For this reason it is worthwhile to extend the study in reference  to clustThe focus is on a covariate at the cluster-level. Such a covariate may be a cluster-level characteristic, such as school-type (e.g. public versus private) in school-based intervention studies, or an aggregate, such as a school’s mean socio-economic status. Associations between the covariate and outcome tend to be much stronger between than within clusters , 13. FurThe data obtained from cluster randomized trials have a multilevel data structure with subjects nested within clusters. Such data have to be analysed by using the mixed model. Ignoring the multilevel data structure results in too liberal tests with respect to the effect of treatment . Our appTo put things in context a school-based intervention study to evaluate the effect of a new type of smoking prevention intervention on smoking behaviour of secondary school students is used as an example. Secondary schools are randomly assigned to treatment conditions and all students within a school receive the same condition. The covariate we consider is educational level; it is binary and measured at the level of the secondary school: vocational schools train their students for specific vocations while high schools prepare their students for follow-up education.yij of student i in school j is given byThe outcome we consider is continuous with higher scores related to higher levels of smoking abstinence. It is very likely scores of students within the same school are correlated, for instance as a result of mutual influence and shared norms towards smoking. Ignoring such correlation results in overoptimistic conclusions with respect to the effect of intervention . To accoxj and has the value 0 for the control and 1 for the intervention. The covariate is denoted zj and has the value 0 for vocational schools and 1 for high schools. Note that both xj and zj have a subscript j but not i since they vary between but not within schools. The regression weights β0, β1 and β2 are the intercept and the effect of the intervention and covariate, respectively. The random school-level effect uj is the discrepancy of the mean in school j and the mean score in its treatment condition and school type, and the random subject-level error term eij is the discrepancy of the score of student i and the mean score of its school j. Both random effects are assumed to be independent of each other and to follow a normal distribution with zero mean and variances σu2 and σe2. The total error variance σ2 = σu2 + σe2 is the sum of these two variance components.Treatment condition is denoted On the basis of the adjusted linear mixed model (1) the treatment effect is the difference in expected outcomes across the two treatments, corrected for the covariate:μ can be replaced by their observed means as calculated from a sample to obtain an estimate of the treatment effect. The standard error of this estimator isn1 and n2 the common school size and number of schools, and ρxz the correlation between treatment condition and the covariate. The larger this correlation, the larger the degree of covariate imbalance. Eq. . The error variances also have an asterisk: On the basis of the unadjusted linear mixed model the treatment effect is the difference in expected outcomes across the treatments:μ by their observed means as calculated from a sample provides an estimate β2 = 0) or it is balanced across treatment conditions  and that higher outcome scores are observed in high schools than in vocational schools (i.e. β2 > 0). Let us define positive imbalance as a situation where, by chance, the random assignment results in more than half of the schools in the intervention condition being high schools. This would imply ignoring the covariate in the statistical model results in an overestimated treatment effect. Negative imbalance is the opposite situation and the treatment effect is underestimated.For simplicity it is assumed that half of the schools are vocational schools and the others are high schools. Furthermore, half of the schools are randomly assigned to receive the intervention, which implies the other half receives the control. Let us assume the intervention results in higher outcome scores , th quantile, for instance, this percentage is equal to 70 when the total number of schools is 20, and it is equal to 56 when the total number of schools is 200. This illustrates large percentage deviations from the expectation are more likely to occur for a small number of clusters than for a large number of clusters.The number of high schools in the intervention condition follows from a hypergeometric distribution with parameters  and Sim  to expreA simulation study was conducted to gain further insight in the size of the effects of covariate imbalance in cluster randomized trials. Data generation and parameter estimation were done in R . Parametρ measures the proportion of the variance that is located at the cluster level. It is calculated as ρ = σu2/(σu2 + σe2), and the values 0.01, 0.05, and 0.1 were used in this simulation study. These values cover a wide range of plausible values, with small values common in large clusters, such as hospitals, and large values common in small clusters, such as households. Without loss of generality the total error variance was fixed to σ2 = σu2 + σe2 = 1. The covariate effect size β2 had levels 0.2, 0.5, and 0.8, which correspond to small, medium and large effect sizes [β2 = 0) because the consequences of ignoring covariate imbalance are expected to be negligible. The degree of covariate imbalance is expressed as quantiles of the hypergeometric distribution and the following values were used: 0.025, 0.05, 0.1, 0.5, 0.9, 0.95, and 0.975. Values above 0.5 imply positive imbalance (i.e. too many high schools in the intervention condition). The value 0.5 implies perfect balance of the covariate across the treatments and is also considered.Four factors are considered in the simulation study: cluster size, intraclass correlation coefficient, covariate effect size and degree of covariate imbalance. For cluster size the values 5, 30 and 50 were used. These values are common in respectively households, school classes and departments in hospitals or companies, and were also used by Maas and Hox . Note thct sizes . We do nβ = 0.8 to detect a medium treatment effect β1 = 0.5 in a test with a two-sided alternative hypothesis and α = 0.05 was calculated from (4). This gives a non-integer value which is rounded upwards such that an even number of clusters is available per treatment condition. Only when an even number of clusters per treatment is used balance of the binary covariate at the cluster level can be achieved. This is important because we want to include perfect balance of the covariate across the treatments in our simulation study (see above). Due to rounding upwards to integer values the nominal power levels were somewhat larger than 0.8, and they also varied across the simulation conditions. In practice the possibility of covariate imbalance is often ignored while calculating the required number of clusters. The required number of clusters is therefore calculated under the assumption of covariate balance (i.e. ρxz = 0), but data are generated under various degrees of imbalance and covariate effect size to study the effect of covariate imbalance on parameter estimates and empirical power.In total 3*3*3*7 = 189 combinations of factor levels were considered and these are called simulation conditions henceforward. For each simulation condition 5000 data sets were generated from the adjusted linear mixed model and analysed by means of the adjusted linear mixed model and unadjusted linear mixed model. For each combination of the cluster size and intraclass correlation coefficient the required number of clusters to achieve a power level 1 − β1 is 0.5 in this simulation study. For the unadjusted linear mixed model Various criteria were used to evaluate the effects of covariate imbalance. The primary focus was on the treatment effect, since this is the parameter of main interest in intervention research. The percentage parameter bias is defined as te value .The second criterion for evaluation is the percentage standard error bias:Here the mean standard error of the treatment effect estimates is compared to the standard deviation of the 5000 treatment effect estimates. Positive bias implies the standard errors are overestimated, which may result in a loss of power. Acceptable biases are below 5 % in absolute value .α = 0.05.The third criterion is the empirical power level. For each simulation condition it is approximated as the percentage of data sets for which the null hypothesis of no treatment effect was rejected in a test with a two-sided alternative hypothesis and type I error rate β2 and the difference between expected covariate scores For all simulation conditions the parameter bias of the adjusted linear mixed model was negligible: the largest bias was −1.1 % (figures not shown). For the unadjusted linear mixed model the parameter biases are much larger because it ignores the covariate and in the worst cases these biases are slightly over 100 %, as is depicted in Fig. n1 = 50 the standard error bias decreases with increasing intraclass correlation coefficient but this effect becomes weaker when the cluster size decreases. Surprisingly the standard error bias is most often largest when the covariate is uncorrelated with treatment.For the adjusted linear mixed model the standard error biases were small and the largest bias was −5.1 % (figures not shown). The standard error biases are much larger for the unadjusted linear mixed model and up to almost 200 %, see Fig. Figure Figure In this simulation study we focussed on cluster randomized trials with a continuous outcome at the individual level and a binary outcome at the cluster level. Our findings are in accordance with those for simple randomized trials with a continuous outcome . CovariaCovariate imbalance has much more severe consequences when the covariate is ignored while analysing the data. For the unadjusted linear mixed model the treatment effect was overestimated or underestimated by at most 100 % and its standard error was overestimated by at most 200 % in our simulation study. In most cases the power levels were below 80 % but for very large levels of positive imbalance they were above 80 %. This stresses the need to carefully consider which covariates are important in the study at hand, to actually measure them and to include them in the statistical model. A new tool based on propensity scores is useful to detect covariate imbalances .For both models and for any of the three criteria of evaluation it was observed that the strongest results occurred when the cluster size was large and the intraclass correlation coefficient was small. This is not surprising because in these cases the number of clusters to achieve 80 % power is smallest. The smaller the number of clusters the more likely the percentage high schools in the intervention condition deviates from 50 %. So one should take extra care in trials with large clusters and small degree of dependence among the subjects within a cluster. For instance, covariate imbalance can result in more severe consequences when the cluster randomized trial has general practices as unit of randomization rather than households.In our simulation we assumed all clusters were of equal size. In practice cluster sizes vary and this can be compensated by adding 11 % more clusters . As we aWe acknowledge the setup of our simulation study is somewhat limited. We considered a continuous outcome variable, a single binary covariate at the cluster level, both levels of the covariate were equally represented, and both treatment groups were of equal size. It would also be interesting to consider an individual-level covariate, such as a pre-treatment score or a socio-demographic variable. We expect the potential implications of imbalance of an individual-level covariate to depend on the between- and within-level variability of such a covariate. The higher the between-level variability as compared to the within-level variability, the more the implications of covariate imbalance will correspond to the implications of covariate imbalance of a covariate at cluster level. On the other extreme, covariate imbalance cannot occur when the individual-level covariate only varies within clusters but not between clusters because treatment condition is a cluster level variable. In that case both the unadjusted linear mixed model and adjusted linear mixed model will yield an unbiased estimate of the treatment effect size, but the associated standard error will be smaller for the adjusted linear mixed model because part of the within-cluster variance is explained by the covariate. The implications of imbalance of an individual-level covariate that varies both between and within clusters will be between these two extremes and will have to be studied in future research. Future research could also focus on trials with more covariates which can be measured at the subject and/or cluster level and which can be measured as categorical or scale variables. In any case we expect a loss of power in adjusted linear mixed models and parameter and standard error biases in unadjusted linear mixed models. As for now, it remains unclear how large the effects may be.We can conclude that covariate imbalance may result in a loss of power in adjusted linear mixed models. It is therefore advocated to be aware of the possibility of covariate imbalance while calculating the number of clusters, or to apply stratified randomization or balance algorithms. In addition, ignoring relevant covariates while analysing the data may lead to severely biased estimates of the treatment effect and its standard error. It is therefore important all relevant covariates are identified, measured and included in the regression model. This recommendation holds for simple randomized trials, but is even more important for cluster randomized trials because for this type of trials the number of units to be randomized is often low.


There is an error in the fourth sentence of the second paragraph of the Introduction. The publisher apologizes for the error. The correct sentence is: Yet in the case of small properties—defined as up to four módulos fiscais , CRA certificates may be issued for the entire area of LR vegetation as well.There is an error in the last sentence of the second paragraph of the Discussion. The publisher apologizes for the error. The correct sentence is: Certainty that CRA trading will pay off initial investments could underpin the landowner's decision, making it likely that prior information about the market—such as that provided here—will be more decisive in determining early entry into the market than relative land prices.There is an error in the last sentence of the fourth paragraph of the Discussion. The publisher apologizes for the error. The correct sentence is: Still, market regulation is needed to facilitate transactions and detail disbursement mechanisms—annuities rather than upfront payment—to ensure engagement of landowners over the long run.There is an error in the second sentence of the “CRA demand and supply” subsection of the Results. The publisher apologizes for the error. The correct sentence is: Of this total, 92 Mha are surplus forest areas—the area of native vegetation exceeding the FC requirements that could be legally deforested—while 55.5 Mha occur within LRs of small properties (Table 1).There is an error in the first sentence of the subsection “The CRA market” of the Results. The publisher apologizes for the error. The correct sentence is: The analysis of the CRA market is based on a partial equilibrium model that uses a mix of municipal land prices  to estimate the supply and demand curves, since land prices themselves reflect discounted production returns into infinity—interviews with 116 farmers across five states confirmed the accuracy of this proxy .The following information is missing from the Funding section: This work was supported by the Climate and Land Use Alliance, Ministério do Meio Ambiente and Deutsche Gesellschaft für Internationale Zusammenarbeit via Project TEEB Regional-Local, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação de Amparo à Pesquisa do Estado de Minas Gerais, Servamb, and the Gordon and Betty Moore Foundation.The following information is missing from the Acknowledgments: We would also like to thank Ana Luiza Champloni and Aloísio de Melo for ideas.