WorldWideScience

Sample records for modelling individuals employing

  1. EMPLOYER BRAND AND ANALYSIS OF INDIVIDUAL POTENTIAL

    Directory of Open Access Journals (Sweden)

    Ljiljana Stošić Mihajlović

    2013-01-01

    Full Text Available As companies and individuals to live their best release? What should companies and individuals were the most successful? What job would bring the most satisfaction and opportunities for further development? What would be the fastest way led to the realization of corporate goals and their own? Answers to these questions can be obtained through analysis of employer brand and Analysis of individual potential (AIP. Employer brand analysis and analysis of individual potential is the process of identifying the strengths and potential of the company as well as a person. In this way, determining what it is that a company or person works best, how to motivate people and to the field of application of discovered talent. The main objective of this procedure is the development of an overall as well as personal and professional development of individuals in the direction of those activities and areas that will bring long-term satisfaction

  2. Collectivism versus individualism in Dutch employment relations

    NARCIS (Netherlands)

    de Leede, Jan; Looise, Jan C.; van Riemsdijk, Maarten

    2004-01-01

    From a very centralistic and collectivistic tradition after World War Two, Dutch employment relations now show a trend towards radical decentralisation and individualisation. What might be the consequences of this trend for labour relations? Do developments still fit within a movement towards

  3. Using the Social Enterprise Intervention (SEI) and Individual Placement and Support (IPS) models to improve employment and clinical outcomes of homeless youth with mental illness.

    Science.gov (United States)

    Ferguson, Kristin M

    2013-09-01

    Prior research reveals high unemployment rates among homeless youth. The literature offers many examples of using evidence-informed and evidence-based supported employment models with vulnerable populations to assist them in obtaining and maintaining employment and concurrently addressing mental health challenges. However, there are few examples to date of these models with homeless youth with mental illness. The purpose of this article was thus to describe a methodology for establishing a university-agency research partnership to design, implement, evaluate, and replicate evidence-informed and evidence-based interventions with homeless youth with mental illness to enhance their employment, mental health, and functional outcomes. Data from two studies are used to illustrate the relationship between vocational skill-building/employment and mental health among homeless youth. The article concludes with a discussion of the implications of conducting community-based participatory employment and clinical intervention research. The author highlights the opportunities and tensions associated with this approach.

  4. Using the Social Enterprise Intervention (SEI) and Individual Placement and Support (IPS) models to improve employment and clinical outcomes of homeless youth with mental illness1

    Science.gov (United States)

    Ferguson, Kristin M.

    2013-01-01

    Prior research reveals high unemployment rates among homeless youth. The literature offers many examples of using evidence-informed and evidence-based supported employment models with vulnerable populations to assist them in obtaining and maintaining employment and concurrently addressing mental health challenges. However, there are few examples to date of these models with homeless youth with mental illness. The purpose of this article was thus to describe a methodology for establishing a university-agency research partnership to design, implement, evaluate, and replicate evidence-informed and evidence-based interventions with homeless youth with mental illness to enhance their employment, mental health, and functional outcomes. Data from two studies are used to illustrate the relationship between vocational skill-building/employment and mental health among homeless youth. The article concludes with a discussion of the implications of conducting community-based participatory employment and clinical intervention research. The author highlights the opportunities and tensions associated with this approach. PMID:24294127

  5. Individual employment, household employment, and risk of poverty in the European Union: a decomposition analysis

    NARCIS (Netherlands)

    Corluy, V.; Vandenbroucke, F.; Cantillon, B.; Vandenbroucke, F.

    2014-01-01

    This chapter investigates the relationship between poverty trends and employment, proceeding in two steps. The first step explores the link between individual employment and household employment. A ‘polarization index’ is defined in terms of the difference between, on the one hand, the actual share

  6. Factors Associated with Employment Status in Individuals with Multiple Sclerosis

    OpenAIRE

    Cadden, Margaret; Arnett, Peter

    2015-01-01

    Background: Unemployment is common in individuals with multiple sclerosis (MS) and is associated with substantial socioeconomic burden. Several MS-related factors have been found to be associated with employment status, including fatigue, depression, cognitive problems, and motor difficulties. However, few studies have examined these factors collectively in predicting employment. The present study aimed to explore these variables together in predicting employment status in MS.

  7. ESSENTIAL CLAUSES OF INDIVIDUAL EMPLOYMENT CONTRACT - QUESTIONS AND ANSWERS

    Directory of Open Access Journals (Sweden)

    Monica Gheorghe

    2016-11-01

    Full Text Available This study aims to analyze the legal texts of the Labour Code which refers to the elements / clauses in individual employment contract and clarifying those that have been essential. Rules of the Labour Code which refer to the contents of the individual employment contract are not consistent. The texts of the La bour Code which refer to the essential and specific clauses in individual employment contract are art. 17 para. (1 - (3, art. 20 and art. 41-48. Also Order no. 64/2003 sets out the mandatory elements that must be included in the individual employment con tract, showing that through negotiation between the parties, the contract may include specific clauses under the law. The analysis is done in the light of the provisions of art. 1179 and art. 1185 of the Civil Code, as in common law. At the end of the stud y, we conclude that certain provisions were essential character to the conclusion of any individual employment contract, others result of the negotiation, have essential character only to the contracting parties, while certain clauses are essential for certain types of individual employment contracts . Finally, it is assessed and the consequences of lack of essential clauses and establish its content contrary to legal norms.

  8. Five-Factor Model of Personality, Work Behavior Self-Efficacy, and Length of Prior Employment for Individuals with Disabilities: An Exploratory Analysis

    Science.gov (United States)

    O'Sullivan, Deirdre; Strauser, David R.; Wong, Alex W. K.

    2012-01-01

    With the continued lower employment rate for persons with disabilities, researchers are focusing more on barriers to employment that reach beyond functional impairment. Personality and self-efficacy have consistently been important factors when considering employment outcomes for persons without disability; less is known about these factors as…

  9. Negotiating Individual Employment Relations, Evidence from four Dutch Organizations

    Directory of Open Access Journals (Sweden)

    Anneke Goudswaard

    2007-05-01

    Full Text Available Our purpose is to assess the actual experiences of companies in the context of individualised employment relationships. We have three questions: (1 what issues of the employment relationship can be individually negotiated in organizations? (scope; (2 what issues of the employment relationship are individually negotiated in organizations? (actual use; (3 what are the advantages and disadvantages of negotiations according to employees and managers?; We conducted four case studies in Dutch companies in different sectors (telecom, insurance, manufacturing and consultancy. The data were collected in a total of 69 semi-structured interviews with line managers, HR managers and shop floor employees. We focused on five topics of the employment relation: contract, working hours, wages, development and performance. We found that the scope for negotiation differs according to topic: there is considerable scope with regard to working hours, development and contract and little scope with regard to wages and performance goals. However, employees and supervisors use the scope for negotiating only for working hours and to a lesser extent development. On other topics negotiations hardly take place (e.g. contract or only under specific conditions (e.g. performance goals in non-routine processes. Furthermore, we found that employees and managers perceive both advantages and disadvantages of negotiations. Considering the (dis advantages our conclusion is that there must be an optimum in the scope and use of negotiating the employment relationship in order to serve conditions as fairness, fit, cost effectiveness and extra-role behaviour.Our paper provides empirical data on how individualised employment relations take place in practice. It offers insight in different companies on the scope for, the actual use of and the effects of individual negotiations on different aspects of the employment relationship.

  10. Virtual reality job interview training and 6-month employment outcomes for individuals with schizophrenia seeking employment.

    Science.gov (United States)

    Smith, Matthew J; Fleming, Michael F; Wright, Michael A; Roberts, Andrea G; Humm, Laura Boteler; Olsen, Dale; Bell, Morris D

    2015-08-01

    Individuals with schizophrenia have low employment rates and the job interview presents a critical barrier for them to obtain employment. Virtual reality training has demonstrated efficacy at improving interview skills and employment outcomes among multiple clinical populations. However, the effects of this training on individuals with schizophrenia are unknown. This study evaluated the efficacy of virtual reality job interview training (VR-JIT) at improving job interview skills and employment outcomes among individuals with schizophrenia in a small randomized controlled trial (n=21 VR-JIT trainees, n=11 waitlist controls). Trainees completed up to 10h of virtual interviews using VR-JIT, while controls received services as usual. Primary outcome measures included two pre-test and two post-test video-recorded role-play interviews scored by blinded raters with expertise in human resources and self-reported interviewing self-confidence. Six-month follow-up data on employment outcomes were collected. Trainees reported that the intervention was easy-to-use, helpful, and prepared them for future interviews. Trainees demonstrated increased role-play scores between pre-test and post-test while controls did not (p=0.001). After accounting for neurocognition and months since prior employment, trainees had greater odds of receiving a job offer by 6month follow-up compared to controls (OR: 8.73, p=0.04) and more training was associated with fewer weeks until receiving a job offer (r=-0.63, pjob interview skills in individuals with schizophrenia. Moreover, trainees had greater odds of receiving a job offer by 6-month follow-up. Future studies could evaluate the effectiveness of VR-JIT within community-based services. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. THE MODIFICATION OF THE INDIVIDUAL EMPLOYMENT CONTRACT ASSUMING UNPREDICTABILITY

    Directory of Open Access Journals (Sweden)

    Ana Vidat

    2012-11-01

    Full Text Available Adapting a gainful occupation to technological or economical development may require the amendment of individual labor contract under which the activity is performed, taking into account the intrinsic dynamics of employment. If the parties, by agreement, determine the content of the individual labor contract, all in agreement, may agree at any time to amend it according to art. 41 para. 1 of the Labour Code. And trough the provisions of civil law – common law for the employment law – are established legal the review of the effects of the legal actdue because of the breakage contractual balance due to change in the circumstances envisaged by the parties in the moment of conclusion of the legal act (the so-called theory of unpredictability, rebus sic stantibus – exception to the principle "pacta sunt servanda". Recourse to the legal document review because its effects are other than the parties agreed to establish and be binding in the moment of conclusion of that agreement. In the present paper we will refer to administrative contracts, given the subject of this paper – namely that the common law for individual employment contract is the civil law rules applicable to civil contracts. So in this paper does not refer to former commercial contracts, since the new Civil Code was achieved unification of private law matter – giving up the commercial contracts.

  12. 75 FR 45039 - Increasing Federal Employment of Individuals With Disabilities

    Science.gov (United States)

    2010-07-30

    ... retention of these individuals. My Administration is committed to increasing the number of individuals with... Management and Budget, shall design model recruitment and hiring strategies for agencies seeking to increase... days of the date the Office of Personnel Management sets forth strategies and programs required under...

  13. The Employment-Crime Association for Individuals Convicted of a Sexual Offense in Their Youth

    NARCIS (Netherlands)

    van den Berg, C.J.W.; Mesters, Geert

    2017-01-01

    Objective We study the bi-directional relationship between employment and crime for individuals convicted for a sexual offense in their youth (JSO) and investigate the moderating influences of age and employment duration. Method A bi-variate dynamic binary choice model is developed to allow for

  14. Enhancing Individual Employability: The Perspective of Engineering Graduates

    Science.gov (United States)

    Nilsson, Staffan

    2010-01-01

    Purpose: Employability includes the ability to find employment and remain employed. Employability includes both hard and soft skills, including formal and actual competence, interpersonal skills, and personal characteristics. This paper aims to focus on illuminating perceptions engineering graduates have regarding employability. More specifically,…

  15. Effects of Non-Employment in Early Work-Life on Subsequent Employment Chances of Individuals in The Netherlands

    NARCIS (Netherlands)

    Luijkx, A.R.C.M.; Wolbers, M.H.J.

    2009-01-01

    In this article, the effects of non-employment in early work-life on subsequent employment chances of individuals in the Netherlands are examined. A main concern is whether the experience of non-employment in the beginning of the career (permanently) damages a workers later employment opportunities

  16. Employability Skills for Individuals with Intellectual Disabilities: Supervisors' versus Teachers' Perspectives

    Science.gov (United States)

    Bonner, Vint K. H.

    2017-01-01

    Employability skills are important for employment access, success, and excellence, regardless of disability status. Importantly, employability skills are essential to the employment success of individuals with intellectual disabilities. Unfortunately, there are differences between the employability skills valued by employers, and the employability…

  17. Individual accessibility and distance from major employment centers: An examination using space-time measures

    Science.gov (United States)

    Weber, J.

    Distance has often been assumed to be an influence on intraurban accessibility, whether in traditional proximity-based measures of accessibility, or through expectations about distance-minimizing travel behavior and the logic of the monocentric model. This paper examines the importance of distance from major employment centers to individual accessibility in Portland, Oregon, using space-time accessibility measures computed using GIS. The results of this research indicate that distance from these locations has mixed results on individual accessibility. This appears to reflect the importance of time, both the time of day activities are scheduled as well as time constraints, to individual activity patterns.

  18. Employment consequences of depressive symptoms and work demands individually and combined

    DEFF Research Database (Denmark)

    Thielen, Karsten; Nygaard, Else; Andersen, Ingelise

    2013-01-01

    BACKGROUND: Denmark, like other Western countries, is recently burdened by increasingly high social spending on employment consequences caused by ill mental health. This might be the result of high work demands affecting persons with ill mental health. Therefore, this study assesses to what extent...... depressive symptoms and high work demands, individually and combined, have an effect on employment consequences. METHODS: We conducted a population-based 7-year longitudinal follow-up study with baseline information from the year 2000 on socio-demographics, lifestyle, depressive symptoms and work demands....... In total, 5785 employed persons, aged 40 and 50 years, were included. Information about employment status, sick leave and work disability was obtained from registers. Logistic regression models were used to measure separate and combined effects of depressive symptoms and work demands on job change...

  19. The impact of atypical employment on individual wellbeing: evidence from a panel of British workers.

    Science.gov (United States)

    Bardasi, Elena; Francesconi, Marco

    2004-05-01

    This study explores the relationship between individual wellbeing and atypical employment, which includes both temporary and part-time employment schemes. Individual wellbeing is measured in terms of subjective indicators of mental health, general health status, life satisfaction, and job satisfaction. It addresses four questions: (1) Are workers on a temporary contract more likely to report poor health and poor life and job satisfaction than those who are employed in permanent jobs? (2) Is this the case for part-time workers compared to those who are in a full-time job? (3) Do changes in employment profiles (e.g., from a fixed-term contract to a permanent job, or from part-time employment to full-time employment) affect individuals' health and life satisfaction? (4) Are there differences in such relationships between men and women? To answer these questions, logistic regression models were used to analyse a panel of almost 7000 male and female workers from the first 10 waves of the British Household Panel Survey, 1991-2000. Controlling for background characteristics, atypical employment does not appear to be associated with adverse health consequences for either men or women, when both health and employment are measured at the same time. However, there is evidence that job satisfaction is reduced for seasonal/casual workers and is higher for part-timers. Taking account of selection issues does not change the general picture: the chances of poor mental and physical health and low life satisfaction are unaffected by atypical employment and some of the effects of job satisfaction persist. In addition, very few employment transitions appear to be consequential for a worsening in health outcomes, which tends to be observed in the case of job satisfaction. Although the pattern of results suggests that atypical forms of employment do not have durable adverse health consequences on workers, public policies that aim at improving the working conditions of workers in weak

  20. Globalisation, the development of constitutionalism and the individual employer

    Directory of Open Access Journals (Sweden)

    K Calitz

    2007-11-01

    Full Text Available To establish which legal system will govern the relationship between parties involved in an international employment contract, the rules of private international law (or conflict of laws must be applied. Each country has its own rules of private international law and each country’s courts will apply its own rules if the court is seized with a matter that involves foreign elements. There may be conflict between the potentially applicable legal systems of countries in terms of the level of protection afforded to employees who are parties to international employment contracts. South Africa has constitutionalised the right to fair labour practices and the question is whether this right is applicable to South African employees working in other countries, or to foreigners working in South Africa who originate from countries where this right is not protected. The answer to this question is to be found in the influence of the Constitution on the rules of private international law as applied by South African courts. It is evident from recent judgments of the Labour Court that the Court will readily assume jurisdiction and will furthermore readily hold that the proper law of the contract is South African law in order to protect the constitutional rights of employees involved in international employment contracts. Had the Labour Court held that the place of performance was still the decisive connecting factor, (as previously decided in most South African cases on this aspect the law of the other countries involved in the international employment relationship could have left employees in a worse position than under South African law. This possibility seems to be one of the important underlying reasons for the Labour Court’s willingness to assume jurisdiction and to hold that the proper law was in fact South African law. In the globalisation context the Labour Court has contributed to the advancement of constitutionalism by developing South Africa

  1. Active Aging for Individuals with Intellectual Disability: Meaningful Community Participation through Employment, Retirement, Service, and Volunteerism

    Science.gov (United States)

    Fesko, Sheila Lynch; Hall, Allison Cohen; Quinlan, Jerrilyn; Jockell, Catherine

    2012-01-01

    As individuals with intellectual and developmental disabilities become more engaged in community employment, it will be critical to consider how their employment experience changes as they age. Similar to other seniors, individuals will need to consider whether they want to maintain their employment, reduce their work commitment, or retire…

  2. Markowitz portfolio optimization model employing fuzzy measure

    Science.gov (United States)

    Ramli, Suhailywati; Jaaman, Saiful Hafizah

    2017-04-01

    Markowitz in 1952 introduced the mean-variance methodology for the portfolio selection problems. His pioneering research has shaped the portfolio risk-return model and become one of the most important research fields in modern finance. This paper extends the classical Markowitz's mean-variance portfolio selection model applying the fuzzy measure to determine the risk and return. In this paper, we apply the original mean-variance model as a benchmark, fuzzy mean-variance model with fuzzy return and the model with return are modeled by specific types of fuzzy number for comparison. The model with fuzzy approach gives better performance as compared to the mean-variance approach. The numerical examples are included to illustrate these models by employing Malaysian share market data.

  3. 26 CFR 1.401-10 - Definitions relating to plans covering self-employed individuals.

    Science.gov (United States)

    2010-04-01

    ... not include a self-employed individual when the term “common-law” employee is used or when the context... insurance salesmen as employees. Furthermore, an individual who is a common-law employee is not a self... is a common-law employee is not a self-employed individual with respect to income attributable to...

  4. Employment and vocational skills among individuals with autism spectrum disorder: predictors, impact, and interventions

    OpenAIRE

    LYDON, SINEAD; HEALY, OLIVE

    2014-01-01

    PUBLISHED Much research has been devoted to early intervention for individuals with Autism Spectrum Disorder (ASD), with a lesser emphasis on research examining the outcomes for, or support of, these individuals as they reach employment-age. Historically, employment opportunities for individuals with ASD have been limited. The current literature review sought to investigate the existing predictors and impact of employment or vocational placements among persons with ASD. Interventions desc...

  5. Employment Interventions for Individuals with ASD: The Relative Efficacy of Supported Employment With or Without Prior Project SEARCH Training.

    Science.gov (United States)

    Schall, Carol M; Wehman, Paul; Brooke, Valerie; Graham, Carolyn; McDonough, Jennifer; Brooke, Alissa; Ham, Whitney; Rounds, Rachael; Lau, Stephanie; Allen, Jaclyn

    2015-12-01

    This paper presents findings from a retrospective observational records review study that compares the outcomes associated with implementation of supported employment (SE) with and without prior Project SEARCH with ASD Supports (PS-ASD) on wages earned, time spent in intervention, and job retention. Results suggest that SE resulted in competitive employment for 45 adults with ASD. Twenty-five individuals received prior intervention through PS-ASD while the other 20 individuals received SE only. Individuals in this sample who received PS-ASD required fewer hours of intervention. Additionally, individuals in the PS-ASD group achieved a mean higher wage and had higher retention rates than their peers who received SE only. Further research with a larger sample is needed to confirm these findings.

  6. The Effect of Postsecondary Education on Employment and Income for Individuals with Intellectual Disabilities

    Science.gov (United States)

    Sannicandro, Tom

    2016-01-01

    The low employment rates of individuals with intellectual disabilities (ID) are a major concern. In 2011 only 34% of adults with ID were employed compared to 76% of adults without disabilities (Siperstein, Parker, & Drascher, 2013). Higher educational attainment is associated with higher employment rates for students with ID (Smith, Grigal,…

  7. The impact of atypical employment on individual wellbeing: evidence from a panel of British workers

    OpenAIRE

    Bardasi, Elena; Francesconi, Marco

    2003-01-01

    This study explores the relationship between individual wellbeing and atypical employment, which includes both temporary and part-time employment schemes. Individual wellbeing is measured in terms of subjective indicators of mental health, general health status, life satisfaction, and job satisfaction. It addresses four questions: (1) Are workers on a temporary contract more likely to report poor health and poor life and job satisfaction than those who are employed in permanent jobs? (2) Is t...

  8. General Papers and Studies Related to the Employment of Individuals with Mental Retardation.

    Science.gov (United States)

    Wehman, Paul, Ed.; Hill, Janet W., Ed.

    Seven papers address the employment of individuals with mental retardation. The first cites nine values critical for employment programs, including opportunities in integrated settings and decent pay for meaningful work. The next paper offers a supported work program consisting of job placement, job-site training, ongoing assessment, and job…

  9. Employers' perception of the costs and the benefits of hiring individuals with autism spectrum disorder in open employment in Australia.

    Science.gov (United States)

    Scott, Melissa; Jacob, Andrew; Hendrie, Delia; Parsons, Richard; Girdler, Sonya; Falkmer, Torbjörn; Falkmer, Marita

    2017-01-01

    Research has examined the benefits and costs of employing adults with autism spectrum disorder (ASD) from the perspective of the employee, taxpayer and society, but few studies have considered the employer perspective. This study examines the benefits and costs of employing adults with ASD, from the perspective of employers. Fifty-nine employers employing adults with ASD in open employment were asked to complete an online survey comparing employees with and without ASD on the basis of job similarity. The findings suggest that employing an adult with ASD provides benefits to employers and their organisations without incurring additional costs.

  10. An Elderly Employment Model For The Thai Automotive Industry

    Directory of Open Access Journals (Sweden)

    Pornrat Sadangharn

    2017-10-01

    Full Text Available This research aims at studying an elderly employment model for the Thai automotive industry. Mixed methods with a sequential exploratory strategy were utilized. Grounded theory was employed by using in-depth interviews to investigate the characteristics of elderly employment in the Thai automotive industry. For this stage of the research, theoretical and purposive sampling was used to select 32 key informants from four groups of stakeholders: (1 elderly workers, (2 employers or human resource managers, (3 government officers, and (4 academics. The findings were then validated using a quantitative approach with structural equation modelling (SEM. A total of 308 elderly workers and human resource managers were surveyed regarding their opinion about elderly employment. Based on the survey, the elderly employment model in the Thai automotive industry, which is comprised of the approach to elderly employment, elderly employment preparation, and key success factors for elderly employment, was revealed to be a good fit. 

  11. In-school service predictors of employment for individuals with intellectual disability.

    Science.gov (United States)

    Park, Jiyoon; Bouck, Emily

    2018-04-17

    Although there are many secondary data analyses of the National Longitudinal Transition Study-2 (NLTS-2) to investigate post-school outcome for students with disabilities, there has been a lack of research with in-school service predictors and post-school outcome for students with specific disability categories. This study was a secondary data analysis of NLTS-2 to investigate the relationship between current employment status and in-school services for individuals with intellectual disability. Statistical methods such as descriptive statistics and logistic regression were used to analyze NLTS-2 data set. The main findings included that in-school services were correlated with current employment status, and that primary disability (i.e., mild intellectual disability and moderate/severe intellectual disability) was associated with current employment status. In-school services are critical in predicting current employment for individuals with intellectual disability. Also, data suggest additional research is needed to investigate various in-school services and variables that could predict employment differences between individuals with mild and moderate/severe intellectual disability. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Effects of Housing First on Employment and Income of Homeless Individuals: Results of a Randomized Trial.

    Science.gov (United States)

    Poremski, Daniel; Stergiopoulos, Vicky; Braithwaite, Erika; Distasio, Jino; Nisenbaum, Rosane; Latimer, Eric

    2016-06-01

    Housing First is emerging as an evidence-based practice for housing and supporting people who are homeless and have a mental illness. The objective of this study was to determine whether Housing First increases the odds of obtaining competitive employment in this population and affects income, including income from informal and illegal sources. A total of 2,148 people with a mental illness were recruited from five Canadian cities while they were homeless, classified as having moderate or high needs, and randomly assigned to Housing First or usual care. Housing First participants with high needs received assertive community treatment (ACT), and those with moderate needs received intensive case management (ICM). Every three months, participants were interviewed about employment and earnings in the previous months (median follow-up=745 days). Regression models were estimated via generalized estimating equations. ICM recipients had lower odds of obtaining employment compared with the control group with moderate needs. The odds of obtaining employment among ICM recipients increased but their employment rate never exceeded that of the control group. For ACT recipients, the odds of obtaining employment were not significantly different from those of the control group. Among Housing First participants, persons employed at baseline, men, and younger participants had greater odds of employment compared with control participants. Housing First did not appear to significantly increase income. This was the first large-scale randomized controlled study of Housing First's effects on employment. Further research is needed to determine how Housing First may be enhanced to increase odds of obtaining employment.

  13. The relationship of sick leave benefits, employment patterns, and individual characteristics to radiation therapy-related fatigue.

    Science.gov (United States)

    Poirier, Patricia

    2006-05-03

    To examine the relationship among sick leave benefits, employment patterns, individual characteristics, and fatigue in patients receiving radiation therapy. Prospective, longitudinal design. A community hospital radiation oncology department. 77 patients receiving radiation therapy to the breast, chest, head and neck, pelvis, or prostate. All were employed at the time of diagnosis. The Piper Integrated Fatigue Model guided the study. The Revised Piper Fatigue Scale (PFS), Brief Fatigue Inventory, and a single-item scale were used to measure five dimensions of subjective fatigue. Sick leave, employment, individual characteristics, and fatigue were measured at baseline, weekly during treatment, and at one month post-treatment. Employment patterns, availability of sick leave benefits, and fatigue. Mean total fatigue scores on the PFS ranged from 0-4.77 at baseline (mean = 0.46, SD = 0.93), 0-8.77 at the completion of treatment (mean = 2.84, SD = 2.40), and 0-4.82 at one month post-treatment (mean = 0.77, SD = 1.20). Side effects, education, living situation, age, treatment site, and work were associated with fatigue along the trajectory of radiation therapy. Study participants who were working at the end of radiation had lower fatigue scores than those who were not. Availability of sick leave benefits was associated with employment patterns during treatment. Work may have benefits during radiation therapy but may be affected by radiation therapy-related fatigue. Management of treatment side effects, including fatigue, may help patients remain in the workforce during radiation.

  14. Individual resilience as a strategy to counter employment barriers for people with epilepsy in Zimbabwe.

    Science.gov (United States)

    Mugumbate, Jacob; Gray, Mel

    2017-09-01

    Understanding individual resilience helps to improve employment opportunities of people with epilepsy. This is significant because, in Zimbabwe, as in many other countries in the Global South, people with epilepsy encounter several barriers in a context of less-than-ideal public services. Despite this disadvantage, some people with epilepsy have better employment outcomes for reasons including level of seizure control, social background, employment support services, and individual resilience. This article reports on data from participants (n=8), who were part of a larger study (n=30) on employment experiences of people with epilepsy in Harare. The study used in-depth interviews with the participants, who were all service users and members of the Epilepsy Support Foundation (ESF) in Harare. The eight resilient participants comprised four males and four females aged between 26-48years, who were selected because, unlike the remaining 22 participants, they had overcome chronic unemployment. Seven of the eight participants were employed, while one had recently become unemployed. Views of service providers (n=7) were sought on the experiences of people with epilepsy through a focus group discussion. The service providers included two health workers, three social service workers, and two disability advocacy workers. Data were analysed using NVivo, a computer-assisted qualitative data analysis package. The study found that participants experienced barriers, such as a lack of medical treatment, yet this was important for education and training, lack of finances for training, and negative attitudes at workplaces. Despite these barriers, participants had overcome chronic unemployment due to their individual resilience characterised by: (i) a 'fighting spirit', (ii) being their own advocates, and (iii) having a mastery over, and acceptance of, their epilepsy. The research concluded that, where people with epilepsy faced barriers, as in Zimbabwe, individual resilience acted as

  15. An employer brand predictive model for talent attraction and retention

    Directory of Open Access Journals (Sweden)

    Annelize Botha

    2011-11-01

    Full Text Available Orientation: In an ever shrinking global talent pool organisations use employer brand to attract and retain talent, however, in the absence of theoretical pointers, many organisations are losing out on a powerful business tool by not developing or maintaining their employer brand correctly. Research purpose: This study explores the current state of knowledge about employer brand and identifies the various employer brand building blocks which are conceptually integrated in a predictive model. Motivation for the study: The need for scientific progress though the accurate representation of a set of employer brand phenomena and propositions, which can be empirically tested, motivated this study. Research design, approach and method: This study was nonempirical in approach and searched for linkages between theoretical concepts by making use of relevant contextual data. Theoretical propositions which explain the identified linkages were developed for purpose of further empirical research. Main findings: Key findings suggested that employer brand is influenced by target group needs, a differentiated Employer Value Proposition (EVP, the people strategy, brand consistency, communication of the employer brand and measurement of Human Resources (HR employer branding efforts. Practical/managerial implications: The predictive model provides corporate leaders and their human resource functionaries a theoretical pointer relative to employer brand which could guide more effective talent attraction and retention decisions. Contribution/value add: This study adds to the small base of research available on employer brand and contributes to both scientific progress as well as an improved practical understanding of factors which influence employer brand.

  16. What do we Know About Improving Employment Outcomes for Individuals with Autism Spectrum Disorder?

    Directory of Open Access Journals (Sweden)

    Carolyn Dudley

    2015-09-01

    Full Text Available Autism spectrum disorder (ASD is the most commonly diagnosed neurological disorder in children. Adults with ASD have some of the poorest employment outcomes in comparison to others with disabilities. While data in Canada is limited, roughly 25 per cent of Americans living with ASD are employed and no more than six per cent are competitively employed. Most earn less than the national minimum hourly wage, endure extended periods of joblessness and frequently shuffle between positions, further diminishing their prospects. Poor employment outcomes result in lower quality of life and often lead to steep economic costs. Governments are wise to pay attention to the poor employment outcomes as the high numbers of children now diagnosed with ASD will become adults in the future in need of employment opportunities. Improving employment outcomes for those living with ASD is an important policy objective. Work opportunities improve quality of life, economic independence, social integration, and ultimately benefit all. Adults with ASD can succeed with the right supports. Fortunately, there are many emerging policy and program options that demonstrate success. This paper conducts a review of studies and provides policy recommendations based on the literature, to help governments identify appropriate policy options. Some key factors are both those that are unique to the individual and the external supports available; namely school, work, and family. For example, factors that contribute to successful employment for people living with ASD may include IQ, social skills and self-determination, but for all, even for the less advantaged, external assistance from schools, employers and family can help. Inclusive special education programs in high school that offer work experiences are critical as are knowledgeable employers who can provide the right types of accommodation and leadership. In the work environment the use of vocational and rehabilitative supports, from

  17. A Conceptual Model for Employer Training to Manage Employee Counter-Productive Behaviors

    Science.gov (United States)

    Rock, Naomi Spickard

    2011-01-01

    The purpose of this study was to develop a model for employer training to manage employees who possess counter-productive behaviors. With the increasing encouragement for employers to hire without discriminating, the number of individuals with disabilities in the workforce will rise. There is limited training in universities and businesses to…

  18. ANALYSIS MODEL FOR RETURN ON CAPITAL EMPLOYED

    Directory of Open Access Journals (Sweden)

    BURJA CAMELIA

    2013-02-01

    Full Text Available At the microeconomic level, the appreciation of the capitals’ profitability is a very complex action which is ofinterest for stakeholders. This study has as main purpose to extend the traditional analysis model for the capitals’profitability, based on the ratio “Return on capital employed”. In line with it the objectives of this work aim theidentification of factors that exert an influence on the capital’s profitability utilized by a company and the measurementof their contribution in the manifestation of the phenomenon. The proposed analysis model is validated on the use caseof a representative company from the agricultural sector. The results obtained reveal that in a company there are somefactors which can act positively on the capitals’ profitability: capital turnover, sales efficiency, increase the share ofsales in the total revenues, improvement of the expenses’ efficiency. The findings are useful both for the decisionmakingfactors in substantiating the economic strategies and for the capital owners who are interested in efficiency oftheir investments.

  19. VR Employment Outcomes of Individuals with Autism Spectrum Disorders: A Decade in the Making

    Science.gov (United States)

    Alverson, Charlotte Y.; Yamamoto, Scott H.

    2018-01-01

    This study utilized hierarchical linear modeling analysis of a 10-year extant dataset from Rehabilitation Services Administration to investigate significant predictors of employment outcomes for vocational rehabilitation (VR) clients with autism. Predictor variables were gender, ethnicity, attained education level, IEP status in high school,…

  20. Individual, employment and psychosocial factors influencing walking to work: Implications for intervention design.

    Directory of Open Access Journals (Sweden)

    Emma J Adams

    Full Text Available Promoting walking for the journey to and from work (commuter walking is a potential strategy for increasing physical activity. Understanding the factors influencing commuter walking is important for identifying target groups and designing effective interventions. This study aimed to examine individual, employment-related and psychosocial factors associated with commuter walking and to discuss the implications for targeting and future design of interventions.1,544 employees completed a baseline survey as part of the 'Walking Works' intervention project (33.4% male; 36.3% aged <30 years. Multivariate logistic regression was used to examine the associations of individual (age, ethnic group, educational qualifications, number of children <16 and car ownership, employment-related (distance lived from work, free car parking at work, working hours, working pattern and occupation and psychosocial factors (perceived behavioural control, intention, social norms and social support from work colleagues with commuter walking.Almost half of respondents (n = 587, 49% were classified as commuter walkers. Those who were aged <30 years, did not have a car, had no free car parking at work, were confident of including some walking or intended to walk to or from work on a regular basis, and had support from colleagues for walking were more likely to be commuter walkers. Those who perceived they lived too far away from work to walk, thought walking was less convenient than using a car for commuting, did not have time to walk, needed a car for work or had always travelled the same way were less likely to be commuter walkers.A number of individual, employment-related and psychosocial factors were associated with commuter walking. Target groups for interventions to promote walking to and from work may include those in older age groups and those who own or have access to a car. Multi-level interventions targeting individual level behaviour change, social support within

  1. Individual, employment and psychosocial factors influencing walking to work: Implications for intervention design.

    Science.gov (United States)

    Adams, Emma J; Esliger, Dale W; Taylor, Ian M; Sherar, Lauren B

    2017-01-01

    Promoting walking for the journey to and from work (commuter walking) is a potential strategy for increasing physical activity. Understanding the factors influencing commuter walking is important for identifying target groups and designing effective interventions. This study aimed to examine individual, employment-related and psychosocial factors associated with commuter walking and to discuss the implications for targeting and future design of interventions. 1,544 employees completed a baseline survey as part of the 'Walking Works' intervention project (33.4% male; 36.3% aged perceived behavioural control, intention, social norms and social support from work colleagues) with commuter walking. Almost half of respondents (n = 587, 49%) were classified as commuter walkers. Those who were aged perceived they lived too far away from work to walk, thought walking was less convenient than using a car for commuting, did not have time to walk, needed a car for work or had always travelled the same way were less likely to be commuter walkers. A number of individual, employment-related and psychosocial factors were associated with commuter walking. Target groups for interventions to promote walking to and from work may include those in older age groups and those who own or have access to a car. Multi-level interventions targeting individual level behaviour change, social support within the workplace and organisational level travel policies may be required in order to promote commuter walking.

  2. INDIVIDUAL EMPLOYMENT CONTRACT SPECIAL STIPULATIONS OTHER THAN THOSE PROVIDED BY THE LABOUR CODE

    Directory of Open Access Journals (Sweden)

    ADA HURBEAN

    2011-04-01

    Full Text Available The individual employment contract parties can negotiate and provide stipulations that govern their juridical labour relations, other than those stipulated by Labour Code, according with the paraghraph1 article 20 of the bill in discussion. In principle, this legal liberty is the expression of the will’s autonomy of the parties to conclude any legal act. We have to say that these stipulations transform the employment contract of an act imposed, an adhesion act in one governed by the principle of contractual freedom, even if the juridical literature calls these nonessential and optional clauses.In concreto, the employee and employer may agree to any provision not contrary to imperative stipulation of law, public order or morality. Thus, in this study we aimed to analyze those terms often encounter in labour relations: terms of intellectual propriety rights, conscience, stability, risk, delegation of responsibilities, objective, restriction of free time, index clause, without claiming exhaustive treatment of this topic, considering the development and adaptation of labor relations in Romania in the European context and beyond.

  3. Exploring Individual and Structural Factors Associated with Employment Among Young Transgender Women of Color Using a No-Cost Transgender Legal Resource Center.

    Science.gov (United States)

    Hill, Brandon J; Rosentel, Kris; Bak, Trevor; Silverman, Michael; Crosby, Richard; Salazar, Laura; Kipke, Michele

    2017-01-01

    The purpose of this study was to explore individual and structural factors associated with employment among young transgender women (TW) of color. Sixty-five trans women of color were recruited from the Transgender Legal Defense and Education Fund to complete a 30-min interviewer-assisted survey assessing sociodemographics, housing, workplace discrimination, job-seeking self-efficacy, self-esteem, perceived public passability, and transactional sex work. Logistic regression models revealed that stable housing (structural factor) and job-seeking self-efficacy (individual factor) were significantly associated with currently being employed. Our findings underscore the need for multilevel approaches to assist TW of color gain employment.

  4. JobTIPS: A Transition to Employment Program for Individuals with Autism Spectrum Disorders

    Science.gov (United States)

    Strickland, Dorothy C.; Coles, Claire D.; Southern, Louise B.

    2013-01-01

    This study evaluated the effectiveness of an internet accessed training program that included Theory of Mind-based guidance, video models, visual supports, and virtual reality practice sessions in teaching appropriate job interview skills to individuals with high functioning Autism Spectrum Disorders. In a randomized study, twenty-two youth, ages…

  5. Employer-driven consumerism: integrating health into the business model.

    Science.gov (United States)

    Thompson, Michael; Checkley, Joseph

    2006-01-01

    Consumer-driven health care is a misnomer. Notwithstanding the enormous role the individual consumer has to play in reshaping the U.S. health care delivery system, this article will focus on the employer as the key driver of change and innovation in the consumerism revolution. American Standard provides a case study of how one major employer has evaluated health care in the context of its business and aggressively integrated consumerism and health into the core of its business. Other companies will appropriately execute consumerism strategies in a fashion consistent with their own needs, culture, resources and populations. However, the principles supporting those strategies will be very much consistent.

  6. INDIVIDUAL EMPLOYMENT CONTRACT SUSPENSION IN CASE OF ACTIVITY INTERRUPTION AND / OR THE TEMPORARY ACTIVITY REDUCTION

    Directory of Open Access Journals (Sweden)

    Olimpia-Monica Matiaş

    2012-11-01

    Full Text Available The economic and financial reasons determined by the current crisis have imposed to the Romanian legislator that, in the flexible regulatory context concerning the labour reports, has to intervene to reduce the loss. The legal framework available to the employer in this situation refers to the provisions of the art. 52, 1st paragraph, letter c, art.52, 3rd paragraph, art.53 and 122, 3rd paragraph, all from Law no.40/20111, for Law no.53/2003 modification and amendment concerning the Labour code. Under conditions of economic crisis, it is natural that employers have the necessary means to efficiently organize their activity, meanwhile keeping its staff on these periods. This does not mean that, during the suspension period the employees can not resign, no need to terminate the suspension provided for in Article 52 line 3 of the Labour Code in order to intervene in the individual labor contract termination. From the employer’s perspective there is no ban imposed to him by art. 60 of the Labour Code in relation to this type of suspension, so that the latter may proceed to dismiss the employee during the unilateral suspension of his labor contract arranged under Article 52 line 3 of the Labour Code.

  7. Employment, Production and Consumption model: Patterns of phase transitions

    Science.gov (United States)

    Lavička, H.; Lin, L.; Novotný, J.

    2010-04-01

    We have simulated the model of Employment, Production and Consumption (EPC) using Monte Carlo. The EPC model is an agent based model that mimics very basic rules of industrial economy. From the perspective of physics, the nature of the interactions in the EPC model represents multi-agent interactions where the relations among agents follow the key laws for circulation of capital and money. Monte Carlo simulations of the stochastic model reveal phase transition in the model economy. The two phases are the phase with full unemployment and the phase with nearly full employment. The economy switches between these two states suddenly as a reaction to a slight variation in the exogenous parameter, thus the system exhibits strong non-linear behavior as a response to the change of the exogenous parameters.

  8. Bivalves: From individual to population modelling

    NARCIS (Netherlands)

    Saraiva, S.; van der Meer, J.; Kooijman, S.A.L.M.

    2014-01-01

    An individual based population model for bivalves was designed, built and tested in a 0D approach, to simulate the population dynamics of a mussel bed located in an intertidal area. The processes at the individual level were simulated following the dynamic energy budget theory, whereas initial egg

  9. Project Career: An individualized postsecondary approach to promoting independence, functioning, and employment success among students with traumatic brain injuries.

    Science.gov (United States)

    Minton, Deborah; Elias, Eileen; Rumrill, Phillip; Hendricks, Deborah J; Jacobs, Karen; Leopold, Anne; Nardone, Amanda; Sampson, Elaine; Scherer, Marcia; Gee Cormier, Aundrea; Taylor, Aiyana; DeLatte, Caitlin

    2017-09-14

    Project Career is a five-year interdisciplinary demonstration project funded by NIDILRR. It provides technology-driven supports, merging Cognitive Support Technology (CST) evidence-based practices and rehabilitation counseling, to improve postsecondary and employment outcomes for veteran and civilian undergraduate students with traumatic brain injury (TBI). Provide a technology-driven individualized support program to improve career and employment outcomes for students with TBI. Project staff provide assessments of students' needs relative to assistive technology, academic achievement, and career preparation; provide CST training to 150 students; match students with mentors; provide vocational case management; deliver job development and placement assistance; and maintain an electronic portal regarding accommodation and career resources. Participating students receive cognitive support technology training, academic enrichment, and career preparatory assistance from trained professionals at three implementation sites. Staff address cognitive challenges using the 'Matching Person with Technology' assessment to accommodate CST use (iPad and selected applications (apps)). JBS International (JBS) provides the project's evaluation. To date, 117 students participate with 63% report improved life quality and 75% report improved academic performance. Project Career provides a national model based on best practices for enabling postsecondary students with TBI to attain academic, employment, and career goals.

  10. The Impact of Intensive Vocation-Related Course Taking on Employment Outcomes for Individuals Who Are Deaf

    Science.gov (United States)

    Cawthon, Stephanie W.; Wendel, Erica M.; Bond, Mark P.; Garberoglio, Carrie Lou

    2016-01-01

    Individuals who are deaf have historically faced significant obstacles to equity in employment. This secondary analysis of data from the second National Longitudinal Transition Study (NLTS2) examined (a) intensive vocation-related courses taken by students who are deaf and (b) their impact on long-term employment outcomes. Deaf students in general…

  11. Motion Model Employment using interacting Motion Model Algorithm

    DEFF Research Database (Denmark)

    Hussain, Dil Muhammad Akbar

    2006-01-01

    model being correct is computed through a likelihood function for each model.  The study presented a simple technique to introduce additional models into the system using deterministic acceleration which basically defines the dynamics of the system.  Therefore, based on this value more motion models can...

  12. 26 CFR 1.401-11 - General rules relating to plans covering self-employed individuals.

    Science.gov (United States)

    2010-04-01

    ... section. (b) General rules. (1) If the amount of employer contributions for common-law employees covered... but no more than $2,500, and that the employer contribution on behalf of common-law employees shall be... for common-law employees covered under the plan is related to the earned income of a self-employed...

  13. Individual and work-related predictors of work outcomes related to sustainable employment among male shift and day workers

    NARCIS (Netherlands)

    van de Ven, H.A.; Hesselink, J.K.; Bultmann, U.; de Boer, M.R.; de Looze, M.P.; van der Klink, J.J.L.; Brouwer, S.

    2014-01-01

    Objectives The aim of this study was to examine which individual and work-related characteristics predict work outcomes related to sustainable employment among male shift and day workers. Methods Between 1 September 2005 and 31 December 2009, data on individual and work-related characteristics of

  14. Individual and work-related predictors of work outcomes related to sustainable employment among male shift and day workers

    NARCIS (Netherlands)

    van de Ven, Hardy A.; Hesselink, John Klein; Bultmann, Ute; de Boer, Michiel R.; de Looze, Michiel P.; van der Klink, Jac J. L.; Brouwer, Sandra

    Objectives The aim of this study was to examine which individual and work-related characteristics predict work outcomes related to sustainable employment among male shift and day workers. Methods Between 1 September 2005 and 31 December 2009, data on individual and work-related characteristics of

  15. Individual Hearing Loss: Characterization, Modelling, Compensation Strategies

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten; Christensen-Dalsgaard, Jakob

    2016-01-01

    It is well-established that hearing loss does not only lead to a reduction of hearing sensitivity. Large individual differences are typically observed among listeners with hearing impairment in a wide range of suprathreshold auditory measures. In many cases, audiometric thresholds cannot fully...... account for such individual differences, which make it challenging to find adequate compensation strategies in hearing devices. How to characterize, model, and compensate for individual hearing loss were the main topics of the fifth International Symposium on Auditory and Audiological Research (ISAAR...

  16. THE ROLE AND IMPORTANCE OF THE FIXED-TERM INDIVIDUAL EMPLOYMENT CONTRACT

    Directory of Open Access Journals (Sweden)

    CARMEN CONSTANTINA NENU

    2013-05-01

    Full Text Available The emergence of new forms of employment contracts, which do not materialize all the classic elements of an employment contract, has remained inevitable. European governments have responded to the problems of lack of activity caused by repeated economic crises, through the approval of new forms of employment, which are more flexible and less protective. These new forms of employment contracts must not create differences and discrimination between employees on the ground of the type of contract. In consequence, an analysis of one of these types of contracts, such as the fixed-term employment contract, is required, in terms of union and national rights. Such an analysis is important for a correct understanding of the role and necessity of employment relationships flexibility in a competitive economy.

  17. Individual model evaluation and probabilistic weighting of models

    International Nuclear Information System (INIS)

    Atwood, C.L.

    1994-01-01

    This note stresses the importance of trying to assess the accuracy of each model individually. Putting a Bayesian probability distribution on a population of models faces conceptual and practical complications, and apparently can come only after the work of evaluating the individual models. Moreover, the primary issue is open-quotes How good is this modelclose quotes? Therefore, the individual evaluations are first in both chronology and importance. They are not easy, but some ideas are given here on how to perform them

  18. Outcomes of a 4-year program with higher education and employment goals for individuals diagnosed with mental illness.

    Science.gov (United States)

    Schindler, Victoria P; Sauerwald, Camille

    2013-01-01

    This study examined outcomes of the first four years (2005-2009) of the Bridge Program, an occupational therapy (OT) program that incorporates principles of supported education and supported employment. This program was developed to assist individuals with mental illness to achieve higher education and employment goals. Forty-eight adult participants with various mental health diagnoses. A quantitative one-group pretest-posttest survey design and posttest qualitative focus groups were used. Participants enrolled in higher education increased from 7 to 11 (pretest=15%; posttest=23%), participants employed increased from 5 to 19 (pretest=10%; posttest=40%), and the combined category of higher education/employment increased from 12 to 30 (pretest=25%; posttest=63%) Statistical significance was achieved from pre to posttest in the employment sample (peducation/employment (peducation sample from pre to posttest (p=0.125). Quantitative and qualitative results support that an OT program incorporating principles of supported education and employment can assist individuals with mental illness to achieve higher education and employment goals. Results also outlined items participants found to be supports and barriers to achieving goals.

  19. 76 FR 42131 - Agency Information Collection Activities: DHS Individual Complaint of Employment Discrimination

    Science.gov (United States)

    2011-07-18

    ... of Employment Discrimination AGENCY: Department of Homeland Security. ACTION: 30-Day Notice and... for all persons, to prohibit discrimination in employment because of race, color, religion, sex, national origin, age, disability, protected genetic information, sexual orientation, or status as a parent...

  20. Individual Placement And Support Services Boost Employment For People With Serious Mental Illnesses, But Funding Is Lacking.

    Science.gov (United States)

    Drake, Robert E; Bond, Gary R; Goldman, Howard H; Hogan, Michael F; Karakus, Mustafa

    2016-06-01

    The majority of people with serious mental illnesses want to work. Individual placement and support services, an evidence-based supported employment intervention, enables about 60 percent of people with serious mental illnesses who receive the services to gain competitive employment and improve their lives, but the approach does not lead to fewer people on government-funded disability rolls. Yet individual placement and support employment services are still unavailable to a large majority of people with serious mental illnesses in the United States. Disability policies and lack of a simple funding mechanism remain the chief barriers. A recent federal emphasis on early-intervention programs may increase access to employment services for people with early psychosis, but whether these interventions will prevent disability over time is unknown. Project HOPE—The People-to-People Health Foundation, Inc.

  1. Mathematical models of behavior of individual animals.

    Science.gov (United States)

    Tsibulsky, Vladimir L; Norman, Andrew B

    2007-01-01

    This review is focused on mathematical modeling of behaviors of a whole organism with special emphasis on models with a clearly scientific approach to the problem that helps to understand the mechanisms underlying behavior. The aim is to provide an overview of old and contemporary mathematical models without complex mathematical details. Only deterministic and stochastic, but not statistical models are reviewed. All mathematical models of behavior can be divided into two main classes. First, models that are based on the principle of teleological determinism assume that subjects choose the behavior that will lead them to a better payoff in the future. Examples are game theories and operant behavior models both of which are based on the matching law. The second class of models are based on the principle of causal determinism, which assume that subjects do not choose from a set of possibilities but rather are compelled to perform a predetermined behavior in response to specific stimuli. Examples are perception and discrimination models, drug effects models and individual-based population models. A brief overview of the utility of each mathematical model is provided for each section.

  2. Exploring Perceived Discrimination Among LGBT Individuals in Turkey in Education, Employment, and Health Care: Results of an Online Survey.

    Science.gov (United States)

    Göçmen, İpek; Yılmaz, Volkan

    2017-01-01

    This article explores the discrimination practices encountered by lesbian, gay, bisexual, and transgender (LGBT) individuals in education, income, employment, and health care in Turkey. Limited quantitative data on LGBT individuals are available in Turkey. This study collected data from 2,875 LGBT individuals through a Web-based survey. The findings suggest that LGBT individuals report perceived direct and indirect discrimination in accessing education, employment, and health care. In a country where LGBT rights are not yet recognized and antidiscrimination legislation covering sexual orientation and gender identity is still nonexistent, findings demonstrate perceived discrimination of LGBTs rarely turns into a legal complaint. Even when they do, most LGBTs in our sample report that they did not feel that the justice system addressed their grievances.

  3. Transition to Adulthood: Employment, Education, and Disengagement in Individuals with Autism Spectrum Disorders

    Science.gov (United States)

    Wei, Xin; Wagner, Mary; Hudson, Laura; Yu, Jennifer W.; Shattuck, Paul

    2015-01-01

    Relatively little is known about the pathways youth with Autism Spectrum Disorders (ASDs) take in the transition to adulthood in terms of employment and postsecondary education. Applying life course sequence analysis to a nationally representative sample of youth with ASDs (n = 120), this study clustered various longitudinal sequences into three…

  4. Disability-Inclusive Employer Practices and Hiring of Individuals with Disabilities

    Science.gov (United States)

    Erickson, William A.; von Schrader, Sarah; Bruyère, M.; VanLooy, Sara A.; Matteson, S.

    2014-01-01

    Purpose: To determine what disability-inclusive policies and practices employers have in place and examine the relationship between these practices and the actual recruitment and hiring of persons with disabilities. Method: A survey 675 of human resources professionals who were members of the Society for Human Resource Management. Results: After…

  5. Family, Employment, and Individual Resource-Based Antecedents of Maternal Work-Family Enrichment from Infancy through Middle Childhood

    Science.gov (United States)

    Zhou, Nan; Buehler, Cheryl

    2015-01-01

    This study used data from the NICHD Study of Early Child Care and Youth Development (N = 1,019) to examine family, employment, and individual antecedents of maternal work-family enrichment from infancy through middle childhood. Work-family conflict and important confounding factors were controlled. From the family domain, higher income-to-needs ratio and social support were associated with higher work-family enrichment. From the employment domain, greater job rewards, benefits of employment for children, and work commitment were associated with higher work-family enrichment. From the individual domain, higher maternal education and extroversion were associated with higher work-family enrichment. No family, employment, and individual characteristics were associated with work-family conflict across time except for partner intimacy. In general, the results supported antecedents of work-family enrichment that supply needed resources. The present study contributed to the literature by identifying antecedents of maternal work-family enrichment across early child developmental stages, which goes beyond examinations of particular life stages and a work-family conflict perspective. Implications for theory and practice are discussed. PMID:26641483

  6. DIFFERENCES OF THE FACTORS AFFECTING THE ATTITUDES OF EMPLOYED INDIVIDUALS TOWARDS GREEN PRODUCT ADVERTISEMENTS BY THEIR DEMOGRAPHIC CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Tahir BENLİ

    2018-01-01

    Full Text Available The reckless consumption of nature to respond to any need has led to the disruption of natural balance and nearly extinction of environmental resources. Environmental problems created by the damage to the structure of nature not only affect the ecological system, but also pose an immense challenge for human health. Hence, the consumers who have become aware that resources and living spaces to maintain their living conditions have been increasingly declining are inclined to adopt a more sensitive attitude in consumption process. Businesses have also turned to green advertising for the promotion of their products and services to strengthen their presence and elude competition with other businesses under these circumstances. This study aims to identify the factors that affect the consumer attitudes of the employed individuals on green advertisements for the businesses, and examine their differences according to demographic features. The reason for the selection of employed individuals is assumption that they will be effective of consumers having purchasing income especially in qualified green product purchasing decisions. The questionnaire form designed for this purpose was conducted on 400 individuals selected through convenience sampling method among people living in central district of Kastamonu. It was found that the factors affecting these employed individuals attitudes towards green product advertisements significantly differ according to gender, marital status, age, education and occupation

  7. Effective Transitional Plan from Secondary Education to Employment for Individuals with Learning Disabilities: A Case Study

    Science.gov (United States)

    Cheong, Loh Sau; Yahya, Sharifah Zainiyah Syed

    2013-01-01

    One of the major goals in the education and training of individuals with special needs is to prepare them for independence. However, in the Malaysian context, parents who have special adolescents are in doubt as to what would be the future of their children soon after they have finished the vocational training. This case study explores the…

  8. The role of political affiliation in employment decisions: A model and research agenda.

    Science.gov (United States)

    Roth, Philip L; Goldberg, Caren B; Thatcher, Jason B

    2017-09-01

    Organizational researchers have studied how individuals identify with groups and organizations and how this affiliation influences behavior for decades (e.g., Tajfel, 1982). Interestingly, investigation into political affiliation and political affiliation similarity in the organizational sciences is extremely rare. This is striking, given the deep political divides that exist between groups of individuals described in the political science literature. We draw from theories based on similarity, organizational identification, and person-environment fit, as well as theoretical notions related to individuating information, to develop a model, the political affiliation model (PAM), which describes the implications of political affiliation and political similarity for employment decisions. We set forth a number of propositions based on PAM, to spur future research in the organizational sciences for a timely topic which has received little attention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Trajectories and models of individual growth

    Directory of Open Access Journals (Sweden)

    Arseniy Karkach

    2006-11-01

    Full Text Available It has long been recognized that the patterns of growth play an important role in the evolution of age trajectories of fertility and mortality (Williams, 1957. Life history studies would benefit from a better understanding of strategies and mechanisms of growth, but still no comparative research on individual growth strategies has been conducted. Growth patterns and methods have been shaped by evolution and a great variety of them are observed. Two distinct patterns - determinate and indeterminate growth - are of a special interest for these studies since they present qualitatively different outcomes of evolution. We attempt to draw together studies covering growth in plant and animal species across a wide range of phyla focusing primarily on the noted qualitative features. We also review mathematical descriptions of growth, namely empirical growth curves and growth models, and discuss the directions of future research.

  10. Beyond labelling: what strategies do nut allergic individuals employ to make food choices? A qualitative study.

    Directory of Open Access Journals (Sweden)

    Julie Barnett

    Full Text Available OBJECTIVE: Food labelling is an important tool that assists people with peanut and tree nut allergies to avoid allergens. Nonetheless, other strategies are also developed and used in food choice decision making. In this paper, we examined the strategies that nut allergic individuals deploy to make safe food choices in addition to a reliance on food labelling. METHODS: THREE QUALITATIVE METHODS: an accompanied shop, in-depth semi-structured interviews, and the product choice reasoning task - were used with 32 patients that had a clinical history of reactions to peanuts and/or tree nuts consistent with IgE-mediated food allergy. Thematic analysis was applied to the transcribed data. RESULTS: Three main strategies were identified that informed the risk assessments and food choice practices of nut allergic individuals. These pertained to: (1 qualities of product such as the product category or the country of origin, (2 past experience of consuming a food product, and (3 sensory appreciation of risk. Risk reasoning and risk management behaviours were often contingent on the context and other physiological and socio-psychological needs which often competed with risk considerations. CONCLUSIONS: Understanding and taking into account the complexity of strategies and the influences of contextual factors will allow healthcare practitioners, allergy nutritionists, and caregivers to advise and educate patients more effectively in choosing foods safely. Governmental bodies and policy makers could also benefit from an understanding of these food choice strategies when risk management policies are designed and developed.

  11. 20 CFR 669.400 - What are the elements of the Individual Employment Plan that is authorized as an intensive service?

    Science.gov (United States)

    2010-04-01

    ... Services § 669.400 What are the elements of the Individual Employment Plan that is authorized as an intensive service? The elements of the Individual Employment Plan (IEP) are: (a) Joint development: The... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What are the elements of the Individual...

  12. Modeling energy fluxes in heterogeneous landscapes employing a mosaic approach

    Science.gov (United States)

    Klein, Christian; Thieme, Christoph; Priesack, Eckart

    2015-04-01

    Recent studies show that uncertainties in regional and global climate and weather simulations are partly due to inadequate descriptions of the energy flux exchanges between the land surface and the atmosphere. One major shortcoming is the limitation of the grid-cell resolution, which is recommended to be about at least 3x3 km² in most models due to limitations in the model physics. To represent each individual grid cell most models select one dominant soil type and one dominant land use type. This resolution, however, is often too coarse in regions where the spatial diversity of soil and land use types are high, e.g. in Central Europe. An elegant method to avoid the shortcoming of grid cell resolution is the so called mosaic approach. This approach is part of the recently developed ecosystem model framework Expert-N 5.0. The aim of this study was to analyze the impact of the characteristics of two managed fields, planted with winter wheat and potato, on the near surface soil moistures and on the near surface energy flux exchanges of the soil-plant-atmosphere interface. The simulated energy fluxes were compared with eddy flux tower measurements between the respective fields at the research farm Scheyern, North-West of Munich, Germany. To perform these simulations, we coupled the ecosystem model Expert-N 5.0 to an analytical footprint model. The coupled model system has the ability to calculate the mixing ratio of the surface energy fluxes at a given point within one grid cell (in this case at the flux tower between the two fields). This approach accounts for the differences of the two soil types, of land use managements, and of canopy properties due to footprint size dynamics. Our preliminary simulation results show that a mosaic approach can improve modeling and analyzing energy fluxes when the land surface is heterogeneous. In this case our applied method is a promising approach to extend weather and climate models on the regional and on the global scale.

  13. Individual skills based volunteerism and life satisfaction among healthcare volunteers in Malaysia: role of employer encouragement, self-esteem and job performance, a cross-sectional study.

    Science.gov (United States)

    Veerasamy, Chanthiran; Sambasivan, Murali; Kumar, Naresh

    2013-01-01

    The purpose of this paper is to analyze two important outcomes of individual skills-based volunteerism (ISB-V) among healthcare volunteers in Malaysia. The outcomes are: job performance and life satisfaction. This study has empirically tested the impact of individual dimensions of ISB-V along with their inter-relationships in explaining the life satisfaction and job performance. Besides, the effects of employer encouragement to the volunteers, demographic characteristics of volunteers, and self-esteem of volunteers on job performance and life satisfaction have been studied. The data were collected through a questionnaire distributed to 1000 volunteers of St. John Ambulance in Malaysia. Three hundred and sixty six volunteers responded by giving their feedback. The model was tested using Structural Equation Modeling (SEM). The main results of this study are: (1) Volunteer duration and nature of contact affects life satisfaction, (2) volunteer frequency has impact on volunteer duration, (3) self-esteem of volunteers has significant relationships with volunteer frequency, job performance and life satisfaction, (4) job performance of volunteers affect their life satisfaction and (5) current employment level has significant relationships with duration of volunteering, self esteem, employer encouragement and job performance of volunteers. The model in this study has been able to explain 39% of the variance in life satisfaction and 45% of the variance in job performance. The current study adds significantly to the body of knowledge on healthcare volunteerism.

  14. Individual Skills Based Volunteerism and Life Satisfaction among Healthcare Volunteers in Malaysia: Role of Employer Encouragement, Self-Esteem and Job Performance, A Cross-Sectional Study

    Science.gov (United States)

    Veerasamy, Chanthiran; Sambasivan, Murali; Kumar, Naresh

    2013-01-01

    The purpose of this paper is to analyze two important outcomes of individual skills-based volunteerism (ISB-V) among healthcare volunteers in Malaysia. The outcomes are: job performance and life satisfaction. This study has empirically tested the impact of individual dimensions of ISB-V along with their inter-relationships in explaining the life satisfaction and job performance. Besides, the effects of employer encouragement to the volunteers, demographic characteristics of volunteers, and self-esteem of volunteers on job performance and life satisfaction have been studied. The data were collected through a questionnaire distributed to 1000 volunteers of St. John Ambulance in Malaysia. Three hundred and sixty six volunteers responded by giving their feedback. The model was tested using Structural Equation Modeling (SEM). The main results of this study are: (1) Volunteer duration and nature of contact affects life satisfaction, (2) volunteer frequency has impact on volunteer duration, (3) self-esteem of volunteers has significant relationships with volunteer frequency, job performance and life satisfaction, (4) job performance of volunteers affect their life satisfaction and (5) current employment level has significant relationships with duration of volunteering, self esteem, employer encouragement and job performance of volunteers. The model in this study has been able to explain 39% of the variance in life satisfaction and 45% of the variance in job performance. The current study adds significantly to the body of knowledge on healthcare volunteerism. PMID:24194894

  15. Individual skills based volunteerism and life satisfaction among healthcare volunteers in Malaysia: role of employer encouragement, self-esteem and job performance, a cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Chanthiran Veerasamy

    Full Text Available The purpose of this paper is to analyze two important outcomes of individual skills-based volunteerism (ISB-V among healthcare volunteers in Malaysia. The outcomes are: job performance and life satisfaction. This study has empirically tested the impact of individual dimensions of ISB-V along with their inter-relationships in explaining the life satisfaction and job performance. Besides, the effects of employer encouragement to the volunteers, demographic characteristics of volunteers, and self-esteem of volunteers on job performance and life satisfaction have been studied. The data were collected through a questionnaire distributed to 1000 volunteers of St. John Ambulance in Malaysia. Three hundred and sixty six volunteers responded by giving their feedback. The model was tested using Structural Equation Modeling (SEM. The main results of this study are: (1 Volunteer duration and nature of contact affects life satisfaction, (2 volunteer frequency has impact on volunteer duration, (3 self-esteem of volunteers has significant relationships with volunteer frequency, job performance and life satisfaction, (4 job performance of volunteers affect their life satisfaction and (5 current employment level has significant relationships with duration of volunteering, self esteem, employer encouragement and job performance of volunteers. The model in this study has been able to explain 39% of the variance in life satisfaction and 45% of the variance in job performance. The current study adds significantly to the body of knowledge on healthcare volunteerism.

  16. [Effectiveness of individual supported employment for people with severe mental disorders].

    Science.gov (United States)

    Rodríguez Pulido, Francisco; Caballero Estebaranz, Nayra; Tallo Aldana, Elena; Méndez Abad, Manuel E; Hernández Álvarez-Sotomayor, M Carmen; López Reig, Susana; Vílchez de León, Patricia Inés; González-Dávila, Enrique

    2017-07-13

    To assess the effectiveness of an individual placement and support (IPS) strategy in people with severe mental disorders in Tenerife Island (Spain). Patients of Community Mental Health Services with severe mental disorders were randomly assigned to two groups. One of them received IPS (n=124), and the control group (n=75) was advised in the usual job search. Patients were followed up for an average of 3.4 years and an analysis was made of how many patients worked at least one day, working hours, wages, the number of contracts and the number of hospital admissions. Non-parametric methods were used to compare the results (Mann-Whitney U test). The percentage of patients who worked at least one day was 99% in the IPS group compared with 75% in the control group; they worked on average 30.1 weeks per year vs 7.4; the monthly salary was € 777.9 vs € 599.9; the number of contracts per person was 3.89 vs 4.85, and hospital admissions were 0.19 vs 2.1. The IPS strategy is effective for the labour integration of people with severe mental illness getting them to work longer, have higher wages and fewer hospital admissions. Copyright © 2017 SESPAS. All rights reserved.

  17. Improved Mental Acuity Forecasting with an Individualized Quantitative Sleep Model

    Directory of Open Access Journals (Sweden)

    Brent D. Winslow

    2017-04-01

    Full Text Available Sleep impairment significantly alters human brain structure and cognitive function, but available evidence suggests that adults in developed nations are sleeping less. A growing body of research has sought to use sleep to forecast cognitive performance by modeling the relationship between the two, but has generally focused on vigilance rather than other cognitive constructs affected by sleep, such as reaction time, executive function, and working memory. Previous modeling efforts have also utilized subjective, self-reported sleep durations and were restricted to laboratory environments. In the current effort, we addressed these limitations by employing wearable systems and mobile applications to gather objective sleep information, assess multi-construct cognitive performance, and model/predict changes to mental acuity. Thirty participants were recruited for participation in the study, which lasted 1 week. Using the Fitbit Charge HR and a mobile version of the automated neuropsychological assessment metric called CogGauge, we gathered a series of features and utilized the unified model of performance to predict mental acuity based on sleep records. Our results suggest that individuals poorly rate their sleep duration, supporting the need for objective sleep metrics to model circadian changes to mental acuity. Participant compliance in using the wearable throughout the week and responding to the CogGauge assessments was 80%. Specific biases were identified in temporal metrics across mobile devices and operating systems and were excluded from the mental acuity metric development. Individualized prediction of mental acuity consistently outperformed group modeling. This effort indicates the feasibility of creating an individualized, mobile assessment and prediction of mental acuity, compatible with the majority of current mobile devices.

  18. Improved Mental Acuity Forecasting with an Individualized Quantitative Sleep Model.

    Science.gov (United States)

    Winslow, Brent D; Nguyen, Nam; Venta, Kimberly E

    2017-01-01

    Sleep impairment significantly alters human brain structure and cognitive function, but available evidence suggests that adults in developed nations are sleeping less. A growing body of research has sought to use sleep to forecast cognitive performance by modeling the relationship between the two, but has generally focused on vigilance rather than other cognitive constructs affected by sleep, such as reaction time, executive function, and working memory. Previous modeling efforts have also utilized subjective, self-reported sleep durations and were restricted to laboratory environments. In the current effort, we addressed these limitations by employing wearable systems and mobile applications to gather objective sleep information, assess multi-construct cognitive performance, and model/predict changes to mental acuity. Thirty participants were recruited for participation in the study, which lasted 1 week. Using the Fitbit Charge HR and a mobile version of the automated neuropsychological assessment metric called CogGauge, we gathered a series of features and utilized the unified model of performance to predict mental acuity based on sleep records. Our results suggest that individuals poorly rate their sleep duration, supporting the need for objective sleep metrics to model circadian changes to mental acuity. Participant compliance in using the wearable throughout the week and responding to the CogGauge assessments was 80%. Specific biases were identified in temporal metrics across mobile devices and operating systems and were excluded from the mental acuity metric development. Individualized prediction of mental acuity consistently outperformed group modeling. This effort indicates the feasibility of creating an individualized, mobile assessment and prediction of mental acuity, compatible with the majority of current mobile devices.

  19. Employing Augmented-Reality-Embedded Instruction to Disperse the Imparities of Individual Differences in Earth Science Learning

    Science.gov (United States)

    Chen, Cheng-ping; Wang, Chang-Hwa

    2015-12-01

    Studies have proven that merging hands-on and online learning can result in an enhanced experience in learning science. In contrast to traditional online learning, multiple in-classroom activities may be involved in an augmented-reality (AR)-embedded e-learning process and thus could reduce the effects of individual differences. Using a three-stage AR-embedded instructional process, we conducted an experiment to investigate the influences of individual differences on learning earth science phenomena of "day, night, and seasons" for junior highs. The mixed-methods sequential explanatory design was employed. In the quantitative phase, factors of learning styles and ICT competences were examined alongside with the overall learning achievement. Independent t tests and ANCOVAs were employed to achieve inferential statistics. The results showed that overall learning achievement was significant for the AR-embedded instruction. Nevertheless, neither of the two learner factors exhibited significant effect on learning achievement. In the qualitative phase, we analyzed student interview records, and a wide variation on student's preferred instructional stages were revealed. These findings could provide an alternative rationale for developing ICT-supported instruction, as our three-stage AR-embedded comprehensive e-learning scheme could enhance instruction adaptiveness to disperse the imparities of individual differences between learners.

  20. Full employment and competition in the Aspen economic model: implications for modeling acts of terrorism.

    Energy Technology Data Exchange (ETDEWEB)

    Sprigg, James A.; Ehlen, Mark Andrew

    2004-11-01

    Acts of terrorism could have a range of broad impacts on an economy, including changes in consumer (or demand) confidence and the ability of productive sectors to respond to changes. As a first step toward a model of terrorism-based impacts, we develop here a model of production and employment that characterizes dynamics in ways useful toward understanding how terrorism-based shocks could propagate through the economy; subsequent models will introduce the role of savings and investment into the economy. We use Aspen, a powerful economic modeling tool developed at Sandia, to demonstrate for validation purposes that a single-firm economy converges to the known monopoly equilibrium price, output, and employment levels, while multiple-firm economies converge toward the competitive equilibria typified by lower prices and higher output and employment. However, we find that competition also leads to churn by consumers seeking lower prices, making it difficult for firms to optimize with respect to wages, prices, and employment levels. Thus, competitive firms generate market ''noise'' in the steady state as they search for prices and employment levels that will maximize profits. In the context of this model, not only could terrorism depress overall consumer confidence and economic activity but terrorist acts could also cause normal short-run dynamics to be misinterpreted by consumers as a faltering economy.

  1. Do inclusive work environments matter? Effects of community-integrated employment on quality of life for individuals with intellectual disabilities.

    Science.gov (United States)

    Blick, Rachel N; Litz, Katherine S; Thornhill, Monica G; Goreczny, Anthony J

    2016-01-01

    More individuals with an intellectual disability now possess prerequisite skills and supports necessary for successful work force integration than did previous generations. The current study compared quality of life of community-integrated workers with those participating in sheltered vocational workshops and adult day care programs. We considered numerous indices of quality of life, including inclusion and community participation; satisfaction within professional services, home life, and day activities; dignity, rights, and respect received from others; fear; choice and control; and family satisfaction. Our data revealed several important differences in quality of life across daytime activities; participants involved in community-integrated employment tended to be younger, indicated a greater sense of community integration, and reported more financial autonomy than did those who participated in adult day care programs and sheltered workshops. However, individuals reported no differences in overall satisfaction across daytime activities. We discuss generational differences across employment status as well as possible explanations to account for high levels of satisfaction across daytime activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Governance Models of Training for Employment: A European Perspective

    Science.gov (United States)

    Greinert, Wolf-Dietrich

    2010-01-01

    Internationally, the question of how to qualify the workforce seems to be of increasing importance for competitive economies. How can politics govern the quantity and quality of employment structures and optimise both? In this article a theoretical framework is outlined that has been developed for the analysis of institutional constructs serving…

  3. Student Employment as a Model for Experiential Learning

    Science.gov (United States)

    Fede, Jacquelyn H.; Gorman, Kathleen S.; Cimini, Maria E.

    2018-01-01

    Background: Evidence suggests experiential learning promotes the development of a range of transferrable skills including communication, responsibility, and social skills. However, many students are unable to participate in internships or other common forms of experiential education because they need to work for pay. University employment has been…

  4. Employers’ perception of the costs and the benefits of hiring individuals with autism spectrum disorder in open employment in Australia

    Science.gov (United States)

    2017-01-01

    Research has examined the benefits and costs of employing adults with autism spectrum disorder (ASD) from the perspective of the employee, taxpayer and society, but few studies have considered the employer perspective. This study examines the benefits and costs of employing adults with ASD, from the perspective of employers. Fifty-nine employers employing adults with ASD in open employment were asked to complete an online survey comparing employees with and without ASD on the basis of job similarity. The findings suggest that employing an adult with ASD provides benefits to employers and their organisations without incurring additional costs. PMID:28542465

  5. Knowledge of physical activity recommendations in adults employed in England: associations with individual and workplace-related predictors.

    Science.gov (United States)

    Knox, Emily C L; Musson, Hayley; Adams, Emma J

    2015-05-23

    Physical activity guidelines state that adults should engage in at least 150 min of moderate to vigorous physical activity (MVPA) per week to benefit health. A high proportion of adults in England fail to reach this target. Accurate knowledge of MVPA guidelines could influence the amount and quality of MVPA engaged in by adults. This study aimed to determine knowledge of the MVPA guideline within a large sample of working adults in England and identify individual and workplace-related predictors of knowledge. 10,992 adults completed an online survey which included questions on demographics, knowledge of the MVPA guideline and workplace predictors for physical activity. Multinomial logistic regression identified predictors of underestimating, overestimating or not knowing the MVPA guideline relative to accurately reporting the guideline for males and females separately. Respondents were 37% male, 95% White, 63% with a degree or higher, and had a mean age of 38.9 ± 11 years. The MVPA guideline was accurately reported by 15% of adults while 13.8% overestimated, 8.9% underestimated and 62.3% failed to provide any estimate of the guideline. Low education predicted underestimation (females: OR = 0.36, 95% CI 0.17, 0.80) and not knowing (males: OR = 0.37, 95% CI 0.14, 0.96; females: OR = 0.36, 95% CI 0.19, 0.69). Ethnicity was a significant predictor for females only (OR 3.55, 95% CI 1.46, 8.63; OR 4.03, 95% CI 1.58, 10.27; OR 3.73, 95% CI 1.67, 8.33). Employer support for physical activity was a significant predictor of accurate knowledge of the MVPA guideline for both males (underestimation: OR = 0.63, 95% CI 0.40, 1.00; 'don't know': OR = 0.71, 95% CI 0.51, 1.00) and females (overestimation: OR = 0.72, 95% CI 0.53, 0.97; underestimation: OR = 0.66, 95% CI 0.47, 0.92; 'don't know': OR = 0.60, 95% CI 0.47, 0.76). Knowledge of the MVPA guideline within working adults in England is low. Employers should play a role in using targeted

  6. An integrative model for measuring graduates’ employability skills—A study in China

    Directory of Open Access Journals (Sweden)

    Wenping Su

    2015-12-01

    Full Text Available Employability is a key issue in graduates’ job-hunting, but little research has been done on that of the graduates in Chinese universities. These universities have been experiencing a decline in their graduate employment since the past decade. This paper attempts to tackle this issue. It reviews the relevant research on employability and develops a research-based theoretical framework to evaluate and analyze the graduates’ employability in China. It adopts multiple approaches to establish the skills that will enhance university students’ employability. Investigating around 100 employers and 200 undergraduates from the universities in Beijing, the paper explores the characteristics of and factors influencing the graduates’ employability. Subsequently, it proposes a qualitative model to measure graduates’ employability. Based on the findings, it discusses the theoretical and practical implications and provides advice for Chinese graduates to improve their employability.

  7. Effects of Employing Ridge Regression in Structural Equation Models.

    Science.gov (United States)

    McQuitty, Shaun

    1997-01-01

    LISREL 8 invokes a ridge option when maximum likelihood or generalized least squares are used to estimate a structural equation model with a nonpositive definite covariance or correlation matrix. Implications of the ridge option for model fit, parameter estimates, and standard errors are explored through two examples. (SLD)

  8. Stochastic wind turbine modeling for individual pitch control

    DEFF Research Database (Denmark)

    Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    and a simplified description of the aerodynamics with sufficient detail to design model-based individual pitch controllers. Combined with a simplified model of the wind turbine, we exemplify how to use the model elements to systematically design an individual pitch controller. The design is investigated...

  9. Individualized Biomathematical Modeling of Fatigue and Performance

    Science.gov (United States)

    2008-05-29

    waking period are omitted in order to avoid confounds from sleep inertia. Gray bars indicate scheduled sleep periods . (b) Performance predictions...i.e., total sleep deprivation; black). Light gray areas indicate nocturnal sleep periods . In this illustration, the bifurcation point is set to...confounds from sleep inertia. Gray bars indicate scheduled sleep periods . (b) Corresponding performance predictions according to the new model

  10. Mental Models, Magical Thinking, And Individual Differences

    Directory of Open Access Journals (Sweden)

    Phil Turner

    2009-01-01

    Full Text Available Broadly, there are two mutually exclusive accounts of how people (non-specialist users reason about and conceptualize interactive technology. The first is based on classical cognitive psychology and is characterized by the term mental model. The second, drawing on concepts from social cognition, observes that people often anthropomorphize technology. We argue that people are able to exhibit both of these quite different styles of cognition, which Baron-Cohen has described as systemizing and empathizing. The former is associated with the drive to analyze, explore, and construct a system, whereas the latter is the ability to spontaneously tune into another’s thoughts and feelings. The propensity to systemize might give rise to a mental model, while the empathizing tendency might tend to anthropomorphize technology. We present an empirical study that lends support for the above position.

  11. Modeling individual animal histories with multistate capture–recapture models

    Science.gov (United States)

    Lebreton, Jean-Dominique; Nichols, James D.; Barker, Richard J.; Pradel, Roger; Spendelow, Jeffrey A.

    2009-01-01

    Many fields of science begin with a phase of exploration and description, followed by investigations of the processes that account for observed patterns. The science of ecology is no exception, and recent decades have seen a focus on understanding key processes underlying the dynamics of ecological systems. In population ecology, emphasis has shifted from the state variable of population size to the demographic processes responsible for changes in this state variable: birth, death, immigration, and emigration. In evolutionary ecology, some of these same demographic processes, rates of birth and death, are also the determinants of fitness. In animal population ecology, the estimation of state variables and their associated vital rates is especially problematic because of the difficulties in sampling such populations and detecting individual animals. Indeed, early capture–recapture models were developed for the purpose of estimating population size, given the reality that all animals are not caught or detected at any sampling occasion. More recently, capture–recapture models for open populations were developed to draw inferences about survival in the face of these same sampling problems. The focus of this paper is on multi‐state mark–recapture models (MSMR), which first appeared in the 1970s but have undergone substantial development in the last 15 years. These models were developed to deal explicitly with biological variation, in that animals in different “states” (classes defined by location, physiology, behavior, reproductive status, etc.) may have different probabilities of survival and detection. Animal transitions between states are also stochastic and themselves of interest. These general models have proven to be extremely useful and provide a way of thinking about a remarkably wide range of important ecological processes. These methods are now at a stage of refinement and sophistication where they can readily be used by biologists to tackle a wide

  12. Absorbed dose in fibrotic microenvironment models employing Monte Carlo simulation

    International Nuclear Information System (INIS)

    Zambrano Ramírez, O.D.; Rojas Calderón, E.L.; Azorín Vega, E.P.; Ferro Flores, G.; Martínez Caballero, E.

    2015-01-01

    The presence or absence of fibrosis and yet more, the multimeric and multivalent nature of the radiopharmaceutical have recently been reported to have an effect on the radiation absorbed dose in tumor microenvironment models. Fibroblast and myofibroblast cells produce the extracellular matrix by the secretion of proteins which provide structural and biochemical support to cells. The reactive and reparative mechanisms triggered during the inflammatory process causes the production and deposition of extracellular matrix proteins, the abnormal excessive growth of the connective tissue leads to fibrosis. In this work, microenvironment (either not fibrotic or fibrotic) models composed of seven spheres representing cancer cells of 10 μm in diameter each with a 5 μm diameter inner sphere (cell nucleus) were created in two distinct radiation transport codes (PENELOPE and MCNP). The purpose of creating these models was to determine the radiation absorbed dose in the nucleus of cancer cells, based on previously reported radiopharmaceutical retain (by HeLa cells) percentages of the 177 Lu-Tyr 3 -octreotate (monomeric) and 177 Lu-Tyr 3 -octreotate-AuNP (multimeric) radiopharmaceuticals. A comparison in the results between the PENELOPE and MCNP was done. We found a good agreement in the results of the codes. The percent difference between the increase percentages of the absorbed dose in the not fibrotic model with respect to the fibrotic model of the codes PENELOPE and MCNP was found to be under 1% for both radiopharmaceuticals. (authors)

  13. Employment outcome and predictors of competitive employment at 2-year follow-up of a vocational rehabilitation programme for individuals with schizophrenia in a high-income welfare society.

    Science.gov (United States)

    Evensen, Stig; Ueland, Torill; Lystad, June Ullevoldsæter; Bull, Helen; Klungsøyr, Ole; Martinsen, Egil W; Falkum, Erik

    2017-04-01

    Employment is an important part of recovery for individuals with schizophrenia. The employment rate for this group is as low as 10% in Norway, and major system related barriers to employment are evident. This study reports the competitive employment outcome at 2-year follow-up of a vocational rehabilitation study augmented with cognitive remediation (CR) or elements from cognitive behaviour therapy (CBT) for individuals with schizophrenia spectrum disorders. It also investigates if global functioning, self-esteem, and depression at baseline predicts employment outcome, and if change in these variables during the intervention period is associated with employment outcome. One hundred and forty-eight participants with schizophrenia spectrum disorders in six Norwegian counties received 10 months vocational rehabilitation augmented with either CBT (n = 84) or CR (n = 64). Both competitive and sheltered workplaces were used. Participants were assessed at baseline, at the end of the intervention period, and at 2-year follow-up. At 2-year follow-up, 21.2% had obtained competitive employment. A further 25.3% had work placements in competitive workplaces. Significant improvements were found in global functioning, self-esteem, and depression during the intervention period, but no significant differences between the two intervention groups. High baseline global functioning and self-esteem, as well as positive change in these variables during the intervention period, were significantly associated with higher competitive employment outcome at 2-year follow-up. The results add to existing evidence that competitive employment is attainable for individuals with schizophrenia. High global functioning and self-esteem were strongly associated with competitive employment outcome.

  14. Risk of latent TB infection in individuals employed in the healthcare sector in Germany: a multicentre prevalence study

    Directory of Open Access Journals (Sweden)

    Harling Melanie

    2010-04-01

    Full Text Available Abstract Background Healthcare workers are still recognised as a high-risk group for latent TB infection (LTBI. Therefore, the screening of people employed in the healthcare sector for active and LTBI is fundamental to infection control programmes in German hospitals. It was the aim of the study to determine the prevalence and putative risk factors of LTBI. Methods We tested 2028 employees in the healthcare sector with the QuantiFERON-Gold In-tube (QFT-IT test between December 2005 and May 2009, either in the course of contact tracing or in serial testing of TB high-risk groups following German OSH legislation. Results A positive IGRA was found in 9.9% of the healthcare workers (HCWs. Nurses and physicians showed similar prevalence rates (9.7% to 9.6%. Analysed by occupational group, the highest prevalence was found in administration staff and ancillary nursing staff (17.4% and 16.7%. None of the individuals in the trainee group showed a positive IGRA result. In the different workplaces the observed prevalence was 14.7% in administration, 12.0% in geriatric care, 14.2% in technicians (radiology, laboratory and pathology, 6.5% in admission ward staff and 8.3% in the staff of pulmonary/infectious disease wards. Putative risk factors for LTBI were age (>55 years: OR14.7, 95% CI 5.1-42.1, being foreign-born (OR 1.99, 95% CI 1.4-2.8, TB in the individual's own history (OR 4.96, 95% CI 1.99-12.3 and previous positive TST results (OR 3.5, 95% CI 2.4-4.98. We observed no statistically significant association with gender, BCG vaccination, workplace or profession. Conclusion The prevalence of LTBI in low-incidence countries depends on age. We found no positive IGRA results among trainees in the healthcare sector. Incidence studies are needed to assess the infection risk. Pre-employment screening might be helpful in this endeavour.

  15. Employment, Production and Consumption model: Patterns of phase transitions

    Czech Academy of Sciences Publication Activity Database

    Lavička, H.; Lin, L.; Novotný, Jan

    2010-01-01

    Roč. 389, č. 8 (2010), s. 1708-1720 ISSN 0378-4371 Institutional research plan: CEZ:AV0Z10480505 Keywords : EPC * Agent based model * Phase transition Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.521, year: 2010

  16. Predictors of job satisfaction among individuals with disabilities: An analysis of South Korea's National Survey of employment for the disabled.

    Science.gov (United States)

    Park, Yujeong; Seo, Dong Gi; Park, Jaekook; Bettini, Elizabeth; Smith, Jamie

    2016-01-01

    This study aims to explore the influences of personal, vocational, and job environment related factors that are associated with job satisfaction of individuals with disabilities in South Korea. Data for wage-based working employees from a nationwide survey were obtained, which resulted in a total number of 417 participants. The six hypotheses and mediation effects of personal and work related environmental factors were tested using the structural equation modeling drawn from existing research evidence. Results revealed that (a) life satisfaction and job related environments directly influenced job satisfaction; (b) the relationship between personal experience and job satisfaction was mediated by life satisfaction for both mild/moderate and severe/profound disabilities group; and (c) the mediating role of job environment between vocational preparedness and job satisfaction was only observed for individuals with mild/moderate disabilities. Summary of findings and implications for future research and practices are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. A Simple Forecasting Model Linking Macroeconomic Policy to Industrial Employment Demand.

    Science.gov (United States)

    Malley, James R.; Hady, Thomas F.

    A study detailed further a model linking monetary and fiscal policy to industrial employment in metropolitan and nonmetropolitan areas of four United States regions. The model was used to simulate the impacts on area and regional employment of three events in the economy: changing real gross national product (GNP) via monetary policy, holding the…

  18. An Evaluation of High School Curricula Employing Using the Element-Based Curriculum Development Model

    Science.gov (United States)

    Aslan, Dolgun; Günay, Rafet

    2016-01-01

    This study was conducted with the aim of evaluating the curricula that constitute the basis of education provision at high schools in Turkey from the perspective of the teachers involved. A descriptive survey model, a quantitative research method was employed in this study. An item-based curriculum evaluation model was employed as part of the…

  19. LINKAGES: An Individual-based Forest Ecosystem Biogeochemistry Model

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This model product contains the source codes for version 1 of the individual-based forest ecosystem biogeochemistry model LINKAGES and two subsequent...

  20. LINKAGES: An Individual-based Forest Ecosystem Biogeochemistry Model

    Data.gov (United States)

    National Aeronautics and Space Administration — This model product contains the source codes for version 1 of the individual-based forest ecosystem biogeochemistry model LINKAGES and two subsequent versions as...

  1. The Employer's Obligation to Inform the Successful Candidate, Namely the Employee, on the Essential Terms of the Individual Employment Contract. National and European Normative Aspects

    Directory of Open Access Journals (Sweden)

    Carmen Constantina Nenu

    2014-05-01

    Full Text Available In the context of a labor market with normative dimensions in constant evolution, the employee status is quite difficult. In consistence with the principle of protecting employee rights, labor law has imposed new measures that counterbalance the employer‟s position of authority within the employment relationship, both at European and national levels. These include the obligation to inform the employee about the essential elements of his working relationship, obligation established at European level by Council Directive 91/533/EEC of 14 October 1991, and at national level by the Labor Code.

  2. Individual-based modeling of ecological and evolutionary processes

    NARCIS (Netherlands)

    DeAngelis, D.L.; Mooij, W.M.

    2005-01-01

    Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential and difference equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis

  3. Real-time individualization of the unified model of performance.

    Science.gov (United States)

    Liu, Jianbo; Ramakrishnan, Sridhar; Laxminarayan, Srinivas; Balkin, Thomas J; Reifman, Jaques

    2017-12-01

    Existing mathematical models for predicting neurobehavioural performance are not suited for mobile computing platforms because they cannot adapt model parameters automatically in real time to reflect individual differences in the effects of sleep loss. We used an extended Kalman filter to develop a computationally efficient algorithm that continually adapts the parameters of the recently developed Unified Model of Performance (UMP) to an individual. The algorithm accomplishes this in real time as new performance data for the individual become available. We assessed the algorithm's performance by simulating real-time model individualization for 18 subjects subjected to 64 h of total sleep deprivation (TSD) and 7 days of chronic sleep restriction (CSR) with 3 h of time in bed per night, using psychomotor vigilance task (PVT) data collected every 2 h during wakefulness. This UMP individualization process produced parameter estimates that progressively approached the solution produced by a post-hoc fitting of model parameters using all data. The minimum number of PVT measurements needed to individualize the model parameters depended upon the type of sleep-loss challenge, with ~30 required for TSD and ~70 for CSR. However, model individualization depended upon the overall duration of data collection, yielding increasingly accurate model parameters with greater number of days. Interestingly, reducing the PVT sampling frequency by a factor of two did not notably hamper model individualization. The proposed algorithm facilitates real-time learning of an individual's trait-like responses to sleep loss and enables the development of individualized performance prediction models for use in a mobile computing platform. © 2017 European Sleep Research Society.

  4. Evaluating the effectiveness of Facebook to impact the knowledge of evidence-based employment practices by individuals with traumatic brain injury: A knowledge translation random control study.

    Science.gov (United States)

    Inge, Katherine J; Graham, Carolyn W; McLaughlin, James W; Erickson, Doug; Wehman, Paul; Seward, Hannah E

    2017-09-14

    Individuals with traumatic brain injury (TBI) experience difficulty with obtaining and maintaining employment post-injury. Although vocational rehabilitation (VR) can be one option to provide individuals with TBI support and services to lead to successful employment outcomes, information about these services can be difficult and confusing to navigate. Providing information on evidence-based employment practices to individuals with TBI through social media could be an effective approach. The objective of this study was to compare the effect of a knowledge translation (KT) strategy and the use of a secret Facebook group, on the knowledge of evidence-based employment research by individuals with traumatic brain injury (TBI). The study used a randomized pretest-posttest control group design. Sixty individuals with TBI were recruited through clubhouse programs in the state where the authors resided as well as through support groups nationally for individuals with TBI, and were randomly assigned to one of two groups. Both groups received information on evidence-based employment practices for individuals with traumatic brain injury (TBI) over a three month period. One group received the information via participation in a secret Facebook group while the comparison group received information as an "e-news" email blast. Participants were assessed pre- and post-intervention with a Likert-scale instrument designed to measure knowledge of evidenced-based employment information for TBI. Both groups gained a significant amount of knowledge between baseline and post-intervention. However, there were no significant differences between groups in knowledge gained at post-intervention. While the study did not identify the most effective means of delivering information to individuals with TBI, it does provide some guidance for future KT research.

  5. Individualism in plant populations: using stochastic differential equations to model individual neighbourhood-dependent plant growth.

    Science.gov (United States)

    Lv, Qiming; Schneider, Manuel K; Pitchford, Jonathan W

    2008-08-01

    We study individual plant growth and size hierarchy formation in an experimental population of Arabidopsis thaliana, within an integrated analysis that explicitly accounts for size-dependent growth, size- and space-dependent competition, and environmental stochasticity. It is shown that a Gompertz-type stochastic differential equation (SDE) model, involving asymmetric competition kernels and a stochastic term which decreases with the logarithm of plant weight, efficiently describes individual plant growth, competition, and variability in the studied population. The model is evaluated within a Bayesian framework and compared to its deterministic counterpart, and to several simplified stochastic models, using distributional validation. We show that stochasticity is an important determinant of size hierarchy and that SDE models outperform the deterministic model if and only if structural components of competition (asymmetry; size- and space-dependence) are accounted for. Implications of these results are discussed in the context of plant ecology and in more general modelling situations.

  6. Developing a Sustainable Practical Model of Graduate Employability for Higher Education

    Directory of Open Access Journals (Sweden)

    Ahmed Umar Rufai

    2015-01-01

    Full Text Available The purpose of this paper is to evolve a sustainable practical model of employability skills that is sure to capture relevant learning aspects of a particular occupational discipline to be used as framework for Undergraduate students to develop their employability potentials. The study was conducted in three Universities and Polytechnics each with three multi-national companies. Data were collected using semi-structured interviews. Using purposeful sampling 18 academic staff and 3 professionals representing company employers were selected as the study participants. The study evolved a model that is work-based, explicit in its outcome, fully articulated and realistic in terms of employability skill experiences. The proposed model can be used to establish a common higher education programme or curricula that is work-based and skill experience oriented, that can encourage students in higher education to think about work place learning more explicitly and reflectively, that will in turn help them to develop a broad range of knowledge, skills, attitudes, and values, each of which ultimately contribute in some manner to graduate employability.  The paper is considered a contribution to the evolution and growth of knowledge on the linkage between higher education and workplace, through which the ‘skill gap’ occurring between the demand of employment and the level of educational preparation of graduates can be bridged. Keywords: Employability, Higher Education, Graduates, Model/Framework,   academic staff, Employers/Professionals

  7. Testing a Model of Undergraduate Competence in Employability Skills and Its Implications for Stakeholders

    Science.gov (United States)

    Jackson, Denise

    2014-01-01

    Despite the development of employability skills being firmly entrenched in higher education's strategic agenda worldwide; recent graduates' standards in certain skills are not meeting industry expectations. This paper presents and tests a model of undergraduate competence in employability skills. It highlights those factors which impact on…

  8. Developing a Sustainable Practical Model of Graduate Employability for Higher Education

    Science.gov (United States)

    Rufai, Ahmed Umar; Bakar, Ab Rahim Bin; Rashi, Abdullah Bin Mat

    2015-01-01

    The purpose of this paper is to evolve a sustainable practical model of employability skills that is sure to capture relevant learning aspects of a particular occupational discipline to be used as framework for Undergraduate students to develop their employability potentials. The study was conducted in three Universities and Polytechnics each with…

  9. A paradox in individual-based models of populations

    NARCIS (Netherlands)

    Van der Meer, J.

    2016-01-01

    The standard dynamic energy budget model is widely used to describe the physiology of individual animals. It assumes thatassimilation rate scales with body surface area, whereas maintenance rate scales with body volume. When the model is usedas the building block of a population model, only limited

  10. A paradox in individual-based models of populations

    NARCIS (Netherlands)

    van der Meer, J.

    2016-01-01

    The standard dynamic energy budget model is widely used to describe the physiology of individual animals. It assumes that assimilation rate scales with body surface area, whereas maintenance rate scales with body volume. When the model is used as the building block of a population model, only

  11. Collaborative Model for Acceleration of Individualized Therapy of Colon Cancer

    Science.gov (United States)

    2015-12-01

    Award Number: W81XWH-11-1-0527 TITLE: Collaborative Model for Acceleration of Individualized Therapy of Colon Cancer PRINCIPAL INVESTIGATOR: Aik...AND SUBTITLE 5a. CONTRACT NUMBER Collaborative Model for Acceleration of Individualized Therapy of Colon Cancer 5b. GRANT NUMBER W81XWH-11-1-0527 5c...neck, lung, breast and colon malignancies, among others. In this preclinical study we assessed the antitumor effects of the novel Plk inhibitor, TAK

  12. ASSESSING INDIVIDUAL PERFORMANCE ON INFORMATION TECHNOLOGY ADOPTION: A NEW MODEL

    OpenAIRE

    Diah Hari Suryaningrum

    2012-01-01

    This paper aims to propose a new model in assessing individual performance on information technology adoption. The new model to assess individual performance was derived from two different theories: decomposed theory of planned behavior and task-technology fit theory. Although many researchers have tried to expand these theories, some of their efforts might lack of theoretical assumptions. To overcome this problem and enhance the coherence of the integration, I used a theory from social scien...

  13. Nonlinear mixed-effects modeling: individualization and prediction.

    Science.gov (United States)

    Olofsen, Erik; Dinges, David F; Van Dongen, Hans P A

    2004-03-01

    The development of biomathematical models for the prediction of fatigue and performance relies on statistical techniques to analyze experimental data and model simulations. Statistical models of empirical data have adjustable parameters with a priori unknown values. Interindividual variability in estimates of those values requires a form of smoothing. This traditionally consists of averaging observations across subjects, or fitting a model to the data of individual subjects first and subsequently averaging the parameter estimates. However, the standard errors of the parameter estimates are assessed inaccurately by such averaging methods. The reason is that intra- and inter-individual variabilities are intertwined. They can be separated by mixed-effects modeling in which model predictions are not only determined by fixed effects (usually constant parameters or functions of time) but also by random effects, describing the sampling of subject-specific parameter values from probability distributions. By estimating the parameters of the distributions of the random effects, mixed-effects models can describe experimental observations involving multiple subjects properly (i.e., yielding correct estimates of the standard errors) and parsimoniously (i.e., estimating no more parameters than necessary). Using a Bayesian approach, mixed-effects models can be "individualized" as observations are acquired that capture the unique characteristics of the individual at hand. Mixed-effects models, therefore, have unique advantages in research on human neurobehavioral functions, which frequently show large inter-individual differences. To illustrate this we analyzed laboratory neurobehavioral performance data acquired during sleep deprivation, using a nonlinear mixed-effects model. The results serve to demonstrate the usefulness of mixed-effects modeling for data-driven development of individualized predictive models of fatigue and performance.

  14. A Network-Individual-Resource Model for HIV Prevention

    Science.gov (United States)

    Johnson, Blair T.; Redding, Colleen A.; DiClemente, Ralph J.; Mustanski, Brian S.; Dodge, Brian M.; Sheeran, Paschal; Warren, Michelle R.; Zimmerman, Rick S.; Fisher, William A.; Conner, Mark T.; Carey, Michael P.; Fisher, Jeffrey D.; Stall, Ronald D.; Fishbein, Martin

    2014-01-01

    HIV is transmitted through dyadic exchanges of individuals linked in transitory or permanent networks of varying sizes. To optimize prevention efficacy, a complementary theoretical perspective that bridges key individual level elements with important network elements can be a foundation for developing and implementing HIV interventions with outcomes that are more sustainable over time and have greater dissemination potential. Toward that end, we introduce a Network-Individual-Resource (NIR) model for HIV prevention that recognizes how exchanges of resources between individuals and their networks underlies and sustains HIV-risk behaviors. Individual behavior change for HIV prevention, then, may be dependent on increasing the supportiveness of that individual's relevant networks for such change. Among other implications, an NIR model predicts that the success of prevention efforts depends on whether the prevention efforts (1) prompt behavior changes that can be sustained by the resources the individual or their networks possess; (2) meet individual and network needs and are consistent with the individual's current situation/developmental stage; (3) are trusted and valued; and (4) target high HIV-prevalence networks. PMID:20862606

  15. A paradox in individual-based models of populations

    OpenAIRE

    Van der Meer, J.

    2016-01-01

    The standard dynamic energy budget model is widely used to describe the physiology of individual animals. It assumes that assimilation rate scales with body surface area, whereas maintenance rate scales with body volume. When the model is used as the building block of a population model, only limited dynamical behaviour, the so-called juvenile-driven cycles, emerges. The reason is that in the model juveniles are competitively superior over adults, because juveniles have a higher surface area-...

  16. Individual based and mean-field modeling of direct aggregation

    KAUST Repository

    Burger, Martin

    2013-10-01

    We introduce two models of biological aggregation, based on randomly moving particles with individual stochasticity depending on the perceived average population density in their neighborhood. In the firstorder model the location of each individual is subject to a density-dependent random walk, while in the second-order model the density-dependent random walk acts on the velocity variable, together with a density-dependent damping term. The main novelty of our models is that we do not assume any explicit aggregative force acting on the individuals; instead, aggregation is obtained exclusively by reducing the individual stochasticity in response to higher perceived density. We formally derive the corresponding mean-field limits, leading to nonlocal degenerate diffusions. Then, we carry out the mathematical analysis of the first-order model, in particular, we prove the existence of weak solutions and show that it allows for measure-valued steady states. We also perform linear stability analysis and identify conditions for pattern formation. Moreover, we discuss the role of the nonlocality for well-posedness of the first-order model. Finally, we present results of numerical simulations for both the first- and second-order model on the individual-based and continuum levels of description. 2012 Elsevier B.V. All rights reserved.

  17. Hybrid Modelling of Individual Movement and Collective Behaviour

    KAUST Repository

    Franz, Benjamin

    2013-01-01

    Mathematical models of dispersal in biological systems are often written in terms of partial differential equations (PDEs) which describe the time evolution of population-level variables (concentrations, densities). A more detailed modelling approach is given by individual-based (agent-based) models which describe the behaviour of each organism. In recent years, an intermediate modelling methodology - hybrid modelling - has been applied to a number of biological systems. These hybrid models couple an individual-based description of cells/animals with a PDE-model of their environment. In this chapter, we overview hybrid models in the literature with the focus on the mathematical challenges of this modelling approach. The detailed analysis is presented using the example of chemotaxis, where cells move according to extracellular chemicals that can be altered by the cells themselves. In this case, individual-based models of cells are coupled with PDEs for extracellular chemical signals. Travelling waves in these hybrid models are investigated. In particular, we show that in contrary to the PDEs, hybrid chemotaxis models only develop a transient travelling wave. © 2013 Springer-Verlag Berlin Heidelberg.

  18. 26 CFR 1.404(e)-1A - Contributions on behalf of a self-employed individual to or under a qualified pension, annuity...

    Science.gov (United States)

    2010-04-01

    ... individual to or under a qualified pension, annuity, or profit-sharing plan. 1.404(e)-1A Section 1.404(e)-1A...) INCOME TAXES Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.404(e)-1A Contributions on behalf of a self-employed individual to or under a qualified pension, annuity, or profit-sharing plan. (a) In...

  19. Modeling Gameplay Enjoyment, Goal Orientations, and Individual Characteristics

    Science.gov (United States)

    Quick, John M.; Atkinson, Robert K.

    2014-01-01

    The purpose of this study was to investigate the relationships between gameplay enjoyment, gaming goal orientations, and individual characteristics. A total of 301 participants were surveyed and the data were analyzed using structural equation modeling. This led to an expanded Gameplay Enjoyment Model (GEM) with 41 game design features that…

  20. Modelling individual temperature profiles from an isolated perfused bovine tongue

    NARCIS (Netherlands)

    Raaymakers, B. W.; Crezee, J.; Lagendijk, J. J.

    2000-01-01

    To predict the temperature distribution during hyperthermia treatments a thermal model that accounts for the thermal effect of blood flow is mandatory. The DIscrete VAsculature (DIVA) thermal model developed at our department is able to do so; geometrically described vessels are handled individually

  1. The Menu Approach to supported employment for individuals with severe and persistent mental illness: Outcomes in an Oregon community based program.

    Science.gov (United States)

    Roush, Sean

    2009-01-01

    The purpose of this study was to determine the vocational outcomes at the Abacus Program, a Menu Approach supported employment program designed to assist individuals with serious mental illness (SMI) achieve competitive employment. A summative evaluation method was used to determine the vocational outcomes between the years 2000-2006 at the Abacus Program. Data was gathered from existing Abacus Program records and the Statistical Package for the Social Sciences (SPSS) 15.0 was used to calculate outcomes. The Abacus Program served 264 clients during the study period. Within those clients, there were 140 cases of vocational services that met study criteria which resulted in 83 successful instances of employment (59%). Initial data from a single site indicate that the Menu Approach to supported employment produces successful employment outcomes comparable to other published studies. Further research is warranted in order to confirm the initial results of this study in other settings. Randomized controlled trials should be conducted in order to compare the outcomes of the Menu Approach to other methods of providing supported employment services to individuals with SMI.

  2. Individual-based modeling of ecological and evolutionary processes

    Science.gov (United States)

    DeAngelis, Donald L.; Mooij, Wolf M.

    2005-01-01

    Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential-equation and difference-equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis for IBMs by describing five major types of individual variation in IBMs: spatial, ontogenetic, phenotypic, cognitive, and genetic. IBMs are now used in almost all subfields of ecology and evolutionary biology. We map those subfields and look more closely at selected key papers on fish recruitment, forest dynamics, sympatric speciation, metapopulation dynamics, maintenance of diversity, and species conservation. Theorists are currently divided on whether IBMs represent only a practical tool for extending classical theory to more complex situations, or whether individual-based theory represents a radically new research program. We feel that the tension between these two poles of thinking can be a source of creativity in ecology and evolutionary theory.

  3. Modeling Feedbacks Between Individual Human Decisions and Hydrology Using Interconnected Physical and Social Models

    Science.gov (United States)

    Murphy, J.; Lammers, R. B.; Proussevitch, A. A.; Ozik, J.; Altaweel, M.; Collier, N. T.; Alessa, L.; Kliskey, A. D.

    2014-12-01

    The global hydrological cycle intersects with human decision making at multiple scales, from dams and irrigation works to the taps in individuals' homes. Residential water consumers are commonly encouraged to conserve; these messages are heard against a background of individual values and conceptions about water quality, uses, and availability. The degree to which these values impact the larger-hydrological dynamics, the way that changes in those values have impacts on the hydrological cycle through time, and the feedbacks by which water availability and quality in turn shape those values, are not well explored. To investigate this domain we employ a global-scale water balance model (WBM) coupled with a social-science-grounded agent-based model (ABM). The integration of a hydrological model with an agent-based model allows us to explore driving factors in the dynamics in coupled human-natural systems. From the perspective of the physical hydrologist, the ABM offers a richer means of incorporating the human decisions that drive the hydrological system; from the view of the social scientist, a physically-based hydrological model allows the decisions of the agents to play out against constraints faithful to the real world. We apply the interconnected models to a study of Tucson, Arizona, USA, and its role in the larger Colorado River system. Our core concept is Technology-Induced Environmental Distancing (TIED), which posits that layers of technology can insulate consumers from direct knowledge of a resource. In Tucson, multiple infrastructure and institutional layers have arguably increased the conceptual distance between individuals and their water supply, offering a test case of the TIED framework. Our coupled simulation allows us to show how the larger system transforms a resource with high temporal and spatial variability into a consumer constant, and the effects of this transformation on the regional system. We use this to explore how pricing, messaging, and

  4. An Opinion Interactive Model Based on Individual Persuasiveness.

    Science.gov (United States)

    Zhou, Xin; Chen, Bin; Liu, Liang; Ma, Liang; Qiu, Xiaogang

    2015-01-01

    In order to study the formation process of group opinion in real life, we put forward a new opinion interactive model based on Deffuant model and its improved models in this paper because current models of opinion dynamics lack considering individual persuasiveness. Our model has following advantages: firstly persuasiveness is added to individual's attributes reflecting the importance of persuasiveness, which means that all the individuals are different from others; secondly probability is introduced in the course of interaction which simulates the uncertainty of interaction. In Monte Carlo simulation experiments, sensitivity analysis including the influence of randomness, initial persuasiveness distribution, and number of individuals is studied at first; what comes next is that the range of common opinion based on the initial persuasiveness distribution can be predicted. Simulation experiment results show that when the initial values of agents are fixed, no matter how many times independently replicated experiments, the common opinion will converge at a certain point; however the number of iterations will not always be the same; the range of common opinion can be predicted when initial distribution of opinion and persuasiveness are given. As a result, this model can reflect and interpret some phenomena of opinion interaction in realistic society.

  5. Modeling of critical experiments employing Raschig rings in uranyl nitrate solution

    International Nuclear Information System (INIS)

    Tanner, J.E.

    1989-01-01

    Four critical experiments employing borated glass rings in concentrated uranyl nitrate solution yielded k eff higher by 0. 04 when modeled with a flux-weighted, homogenized cross section set than when modeled with discrete rings. k eff varied by 0.014 for a 10% boron uncertainty and by up to 0.04 for a 10% packing fraction uncertainty

  6. Feature Compensation Employing Multiple Environmental Models for Robust In-Vehicle Speech Recognition

    Science.gov (United States)

    Kim, Wooil; Hansen, John H. L.

    An effective feature compensation method is developed for reliable speech recognition in real-life in-vehicle environments. The CU-Move corpus, used for evaluation, contains a range of speech and noise signals collected for a number of speakers under actual driving conditions. PCGMM-based feature compensation, considered in this paper, utilizes parallel model combination to generate noise-corrupted speech model by combining clean speech and the noise model. In order to address unknown time-varying background noise, an interpolation method of multiple environmental models is employed. To alleviate computational expenses due to multiple models, an Environment Transition Model is employed, which is motivated from Noise Language Model used in Environmental Sniffing. An environment dependent scheme of mixture sharing technique is proposed and shown to be more effective in reducing the computational complexity. A smaller environmental model set is determined by the environment transition model for mixture sharing. The proposed scheme is evaluated on the connected single digits portion of the CU-Move database using the Aurora2 evaluation toolkit. Experimental results indicate that our feature compensation method is effective for improving speech recognition in real-life in-vehicle conditions. A reduction of 73.10% of the computational requirements was obtained by employing the environment dependent mixture sharing scheme with only a slight change in recognition performance. This demonstrates that the proposed method is effective in maintaining the distinctive characteristics among the different environmental models, even when selecting a large number of Gaussian components for mixture sharing.

  7. Precarious employment is a risk factor for poor mental health in young individuals in Sweden: a cohort study with multiple follow-ups.

    Science.gov (United States)

    Canivet, Catarina; Bodin, Theo; Emmelin, Maria; Toivanen, Susanna; Moghaddassi, Mahnaz; Östergren, Per-Olof

    2016-08-02

    The globalisation of the economy and the labour markets has resulted in a growing proportion of individuals who find themselves in a precarious labour market situation, especially among the young. This pertains also to the Nordic countries, despite their characterisation as well developed welfare states with active labour market policies. This should be viewed against the background of a number of studies, which have shown that several aspects of precarious employment are detrimental to mental health. However, longitudinal studies from the Nordic region that examine the impact of precarious labour market conditions on mental health in young individuals are currently lacking. The present study aims to examine this impact in a general cohort of Swedish young people. Postal questionnaires were sent out in 1999/2000 to a stratified random sample of the Scania population, Sweden; the response rate was 58 %. All of those who responded at baseline were invited to follow-ups after 5 and 10 years. Employment precariousness was determined based on detailed questions about present employment, previous unemployment, and self-rated risk of future unemployment. Mental health was assessed by GHQ-12. For this study individuals in the age range of 18-34 years at baseline, who were active in the labour market (employed or seeking job) and had submitted complete data from 1999/2000, 2005, and 2010 on employment precariousness and mental health status, were selected (N = 1135). Forty-two percent of the participants had a precarious employment situation at baseline. Labour market trajectories that included precarious employment in 1999/2000 or 2005 predicted poor mental health in 2010: the incidence ratio ratio was 1.4 (95 % CI: 1.1-2.0) when excluding all individuals with mental health problems at baseline and adjusting for age, gender, social support, social capital, and economic difficulties in childhood. The population attributable fraction regarding poor mental health in the

  8. Precarious employment is a risk factor for poor mental health in young individuals in Sweden: a cohort study with multiple follow-ups

    Directory of Open Access Journals (Sweden)

    Catarina Canivet

    2016-08-01

    Full Text Available Abstract Background The globalisation of the economy and the labour markets has resulted in a growing proportion of individuals who find themselves in a precarious labour market situation, especially among the young. This pertains also to the Nordic countries, despite their characterisation as well developed welfare states with active labour market policies. This should be viewed against the background of a number of studies, which have shown that several aspects of precarious employment are detrimental to mental health. However, longitudinal studies from the Nordic region that examine the impact of precarious labour market conditions on mental health in young individuals are currently lacking. The present study aims to examine this impact in a general cohort of Swedish young people. Methods Postal questionnaires were sent out in 1999/2000 to a stratified random sample of the Scania population, Sweden; the response rate was 58 %. All of those who responded at baseline were invited to follow-ups after 5 and 10 years. Employment precariousness was determined based on detailed questions about present employment, previous unemployment, and self-rated risk of future unemployment. Mental health was assessed by GHQ-12. For this study individuals in the age range of 18–34 years at baseline, who were active in the labour market (employed or seeking job and had submitted complete data from 1999/2000, 2005, and 2010 on employment precariousness and mental health status, were selected (N = 1135. Results Forty-two percent of the participants had a precarious employment situation at baseline. Labour market trajectories that included precarious employment in 1999/2000 or 2005 predicted poor mental health in 2010: the incidence ratio ratio was 1.4 (95 % CI: 1.1–2.0 when excluding all individuals with mental health problems at baseline and adjusting for age, gender, social support, social capital, and economic difficulties in childhood. The population

  9. Employing the intelligence cycle process model within the Homeland Security Enterprise

    OpenAIRE

    Stokes, Roger L.

    2013-01-01

    CHDS State/Local The purpose of this thesis was to examine the employment and adherence of the intelligence cycle process model within the National Network of Fusion Centers and the greater Homeland Security Enterprise by exploring the customary intelligence cycle process model established by the United States Intelligence Community (USIC). This thesis revealed there are various intelligence cycle process models used by the USIC and taught to the National Network. Given the numerous differ...

  10. Modelling community, family, and individual determinants of childhood dental caries

    NARCIS (Netherlands)

    Duijster, D.; Loveren, C. van; Dusseldorp, E.; Verrips, G.H.W.

    2014-01-01

    This cross-sectional study empirically tested a theoretical model of pathways and inter-relationships among community, family, and individual determinants of childhood dental caries in a sample of 630, 6-year-old children from the Netherlands. Children's decayed, missing, and filled teeth (dmft)

  11. An Integrative Model of Individual Predisposition and Contextual ...

    African Journals Online (AJOL)

    Specifically, our integrative model makes connection between individuals' personality factor of openness and the contextual factors. The contextual factors reflect human capital of education and experience, motivational resources representing self-efficacy and initiative and networking behaviour influencing opportunity ...

  12. Individual loss reserving with the Multivariate Skew Normal model

    NARCIS (Netherlands)

    Pigeon, M.; Antonio, K.; Denuit, M.

    2011-01-01

    In general insurance, the evaluation of future cash ows and solvency capital has become increasingly important. To assist in this process, the present paper proposes an individual discrete-time loss re- serving model describing the occurrence, the reporting delay, the timeto the first payment, and

  13. Individual based model of slug population and spatial dynamics

    NARCIS (Netherlands)

    Choi, Y.H.; Bohan, D.A.; Potting, R.P.J.; Semenov, M.A.; Glen, D.M.

    2006-01-01

    The slug, Deroceras reticulatum, is one of the most important pests of agricultural and horticultural crops in UK and Europe. In this paper, a spatially explicit individual based model (IbM) is developed to study the dynamics of a population of D. reticulatum. The IbM establishes a virtual field

  14. Knowledge Growth: Applied Models of General and Individual Knowledge Evolution

    Science.gov (United States)

    Silkina, Galina Iu.; Bakanova, Svetlana A.

    2016-01-01

    The article considers the mathematical models of the growth and accumulation of scientific and applied knowledge since it is seen as the main potential and key competence of modern companies. The problem is examined on two levels--the growth and evolution of objective knowledge and knowledge evolution of a particular individual. Both processes are…

  15. An Individual-based Probabilistic Model for Fish Stock Simulation

    Directory of Open Access Journals (Sweden)

    Federico Buti

    2010-08-01

    Full Text Available We define an individual-based probabilistic model of a sole (Solea solea behaviour. The individual model is given in terms of an Extended Probabilistic Discrete Timed Automaton (EPDTA, a new formalism that is introduced in the paper and that is shown to be interpretable as a Markov decision process. A given EPDTA model can be probabilistically model-checked by giving a suitable translation into syntax accepted by existing model-checkers. In order to simulate the dynamics of a given population of soles in different environmental scenarios, an agent-based simulation environment is defined in which each agent implements the behaviour of the given EPDTA model. By varying the probabilities and the characteristic functions embedded in the EPDTA model it is possible to represent different scenarios and to tune the model itself by comparing the results of the simulations with real data about the sole stock in the North Adriatic sea, available from the recent project SoleMon. The simulator is presented and made available for its adaptation to other species.

  16. Multilevel Modeling of Individual and Group Level Mediated Effects.

    Science.gov (United States)

    Krull, J L; MacKinnon, D P

    2001-04-01

    This article combines procedures for single-level mediational analysis with multilevel modeling techniques in order to appropriately test mediational effects in clustered data. A simulation study compared the performance of these multilevel mediational models with that of single-level mediational models in clustered data with individual- or group-level initial independent variables, individual- or group-level mediators, and individual level outcomes. The standard errors of mediated effects from the multilevel solution were generally accurate, while those from the single-level procedure were downwardly biased, often by 20% or more. The multilevel advantage was greatest in those situations involving group-level variables, larger group sizes, and higher intraclass correlations in mediator and outcome variables. Multilevel mediational modeling methods were also applied to data from a preventive intervention designed to reduce intentions to use steroids among players on high school football teams. This example illustrates differences between single-level and multilevel mediational modeling in real-world clustered data and shows how the multilevel technique may lead to more accurate results.

  17. A paradox in individual-based models of populations.

    Science.gov (United States)

    van der Meer, Jaap

    2016-01-01

    The standard dynamic energy budget model is widely used to describe the physiology of individual animals. It assumes that assimilation rate scales with body surface area, whereas maintenance rate scales with body volume. When the model is used as the building block of a population model, only limited dynamical behaviour, the so-called juvenile-driven cycles, emerges. The reason is that in the model juveniles are competitively superior over adults, because juveniles have a higher surface area-to-volume ratio. Maintenance requirements for adults are therefore relatively large, and a reduced assimilation rate as a result of lowered food levels will easily become insufficient. Here, an alternative dynamic energy budget model is introduced that gives rise to adult-driven cycles, which may be closer to what is often observed in reality. However, this comes at the price of a rather odd description of the individual, in that maintenance scales with body area and assimilation rate with body volume, resulting in unbounded exponential body growth. I make a plea to solve the paradox and come up with reliable descriptions at both the individual and the population level.

  18. The Employment of spatial autoregressive models in predicting demand for natural gas

    International Nuclear Information System (INIS)

    Castro, Jorge Henrique de; Silva, Alexandre Pinto Alves da

    2010-01-01

    Develop the natural gas network is critical success factor for the distribution company. It is a decision that employs the demand given location 'x' and a future time 't' so that the net allows the best conditions for the return of the capital. In this segment, typical network industry, the spatial infra-structure vision associated to the market allows better evaluation of the business because to mitigate costs and risks. In fact, economic models little developed in order to assess the question of the location, due to its little employment by economists. The objective of this article is to analyze the application of spatial perspective in natural gas demand forecasting and to identify the models that can be employed observing issues of dependency and spatial heterogeneity; as well as the capacity of mapping of variables associated with the problem. (author)

  19. Modelling biological invasions: Individual to population scales at interfaces

    KAUST Repository

    Belmonte-Beitia, J.

    2013-10-01

    Extracting the population level behaviour of biological systems from that of the individual is critical in understanding dynamics across multiple scales and thus has been the subject of numerous investigations. Here, the influence of spatial heterogeneity in such contexts is explored for interfaces with a separation of the length scales characterising the individual and the interface, a situation that can arise in applications involving cellular modelling. As an illustrative example, we consider cell movement between white and grey matter in the brain which may be relevant in considering the invasive dynamics of glioma. We show that while one can safely neglect intrinsic noise, at least when considering glioma cell invasion, profound differences in population behaviours emerge in the presence of interfaces with only subtle alterations in the dynamics at the individual level. Transport driven by local cell sensing generates predictions of cell accumulations along interfaces where cell motility changes. This behaviour is not predicted with the commonly used Fickian diffusion transport model, but can be extracted from preliminary observations of specific cell lines in recent, novel, cryo-imaging. Consequently, these findings suggest a need to consider the impact of individual behaviour, spatial heterogeneity and especially interfaces in experimental and modelling frameworks of cellular dynamics, for instance in the characterisation of glioma cell motility. © 2013 Elsevier Ltd.

  20. Toward an Integrated Competence-based System Supporting Lifelong Learning and Employability: Concepts, Model, and Challenges

    NARCIS (Netherlands)

    Miao, Yongwu; Van der Klink, Marcel; Boon, Jo; Sloep, Peter; Koper, Rob

    2009-01-01

    Miao, Y., Van der Klink, M., Boon, J., Sloep, P. B., & Koper, R. (2009). Toward an Integrated Competence-based System Supporting Lifelong Learning and Employability: Concepts, Model, and Challenges. In M. Spaniol, Q. Li, R. Klamma & R. W. H. Lau (Eds.), Proceedings of the 8th International

  1. Toward an Integrated Competence-based System Supporting Lifelong Learning and Employability: Concepts, Model, and Challenges

    NARCIS (Netherlands)

    Miao, Yongwu; Van der Klink, Marcel; Boon, Jo; Sloep, Peter; Koper, Rob

    2009-01-01

    Miao, Y., Van der Klink, M., Boon, J., Sloep, P. B., & Koper, R. (2009). Toward an Integrated Competence-based System Supporting Lifelong Learning and Employability: Concepts, Model, and Challenges. Presentation at the 8th International Conference Advances in Web Based Learning - ICWL 2009. August,

  2. IBSEM: An Individual-Based Atlantic Salmon Population Model.

    Directory of Open Access Journals (Sweden)

    Marco Castellani

    Full Text Available Ecology and genetics can influence the fate of individuals and populations in multiple ways. However, to date, few studies consider them when modelling the evolutionary trajectory of populations faced with admixture with non-local populations. For the Atlantic salmon, a model incorporating these elements is urgently needed because many populations are challenged with gene-flow from non-local and domesticated conspecifics. We developed an Individual-Based Salmon Eco-genetic Model (IBSEM to simulate the demographic and population genetic change of an Atlantic salmon population through its entire life-cycle. Processes such as growth, mortality, and maturation are simulated through stochastic procedures, which take into account environmental variables as well as the genotype of the individuals. IBSEM is based upon detailed empirical data from salmon biology, and parameterized to reproduce the environmental conditions and the characteristics of a wild population inhabiting a Norwegian river. Simulations demonstrated that the model consistently and reliably reproduces the characteristics of the population. Moreover, in absence of farmed escapees, the modelled populations reach an evolutionary equilibrium that is similar to our definition of a 'wild' genotype. We assessed the sensitivity of the model in the face of assumptions made on the fitness differences between farm and wild salmon, and evaluated the role of straying as a buffering mechanism against the intrusion of farm genes into wild populations. These results demonstrate that IBSEM is able to capture the evolutionary forces shaping the life history of wild salmon and is therefore able to model the response of populations under environmental and genetic stressors.

  3. DEVELOPMENT OF INDIVIDUAL TREE GROWTH MODELS BASED ON DIFFERENTIAL EQUATIONS

    Directory of Open Access Journals (Sweden)

    Breno Rodrigues Mendes

    2006-09-01

    Full Text Available This study generate individual tree non-linear models from differential equation and evaluated the adjustment quality to express the basal area growth. The data base is from continuous forest inventory of clonal Eucalyptus spp. plantations, given by Aracruz Cellulose Company, located in the Brazilian costal region, Bahia and Espirito Santo states. The model precision was verified by ratio likelihood test, by mean square error (MSE and by graphical residual analysis. The results showed that the complete model with 3 parameters, developed from the original model with one regressor, was superior to the other models, due to the inclusion of stand based variables, such as: clone, total height (HT, dominant height (HD, quadratic diameter (Dg, Basal Area (G, site index (IS and Density (N, generating a new model, called Complete Model III. The improvement of the precision was highly significant when compared to another models. Consequently, this model provides information with a high degree of precision and accuracy for the forest companies planning.

  4. A community model of ciliate Tetrahymena and bacteria E. coli. Part 1: Individual-based models of Tetrahymena and E. coli populations

    Energy Technology Data Exchange (ETDEWEB)

    Jaworska, J.S.; Hallam, T.G.; Schultz, T.W. [Univ. of Tennessee, Knoxville, TN (United States)

    1996-03-01

    The dynamics of a microbial community consisting of a eucaryotic ciliate Tetrahymena pyriformis and procaryotic. Escherichia coli in a batch culture is explored by employing an individual-based approach. In this portion of the article, Part 1, population models are presented. Because both models are individual-based, models of individual organisms are developed prior to construction of the population models. The individual models use an energy budget method in which growth depends on energy gain from feeding and energy sinks such as maintenance and reproduction. These models are not limited by simplifying assumptions about constant yield, constant energy sinks and Monod growth kinetics as are traditional models of microbial organisms. Population models are generated from individual models by creating distinct individual types and assigning to each type the number of real individuals they represent. A population is a compilation of individual types that vary in a phase of cell cycle and physiological parameters such as filtering rate for ciliates and maximum anabolic rate for bacteria. An advantage of the developed models is that they realistically describe the growth of the individual cells feeding on resource which varies in density and composition. Part 2, the core of the project, integrates models into a dynamic microbial community and provides model analysis based upon available data.

  5. INDIVIDUAL-BASED MODELS: POWERFUL OR POWER STRUGGLE?

    Science.gov (United States)

    Willem, L; Stijven, S; Hens, N; Vladislavleva, E; Broeckhove, J; Beutels, P

    2015-01-01

    Individual-based models (IBMs) offer endless possibilities to explore various research questions but come with high model complexity and computational burden. Large-scale IBMs have become feasible but the novel hardware architectures require adapted software. The increased model complexity also requires systematic exploration to gain thorough system understanding. We elaborate on the development of IBMs for vaccine-preventable infectious diseases and model exploration with active learning. Investment in IBM simulator code can lead to significant runtime reductions. We found large performance differences due to data locality. Sorting the population once, reduced simulation time by a factor two. Storing person attributes separately instead of using person objects also seemed more efficient. Next, we improved model performance up to 70% by structuring potential contacts based on health status before processing disease transmission. The active learning approach we present is based on iterative surrogate modelling and model-guided experimentation. Symbolic regression is used for nonlinear response surface modelling with automatic feature selection. We illustrate our approach using an IBM for influenza vaccination. After optimizing the parameter spade, we observed an inverse relationship between vaccination coverage and the clinical attack rate reinforced by herd immunity. These insights can be used to focus and optimise research activities, and to reduce both dimensionality and decision uncertainty.

  6. A partnership-based model for embedding employability in urban planning education

    Directory of Open Access Journals (Sweden)

    Neale Blair

    2016-01-01

    Full Text Available This paper proposes a partnership-based model for embedding employability in urban planning education. The model is based on the author’s experiences of implementing an international project which supported the development of employability skills in urban and regional planning education in Malawi. Since independence, urban planners have typically trained outside the country, attending university in the UK and other Commonwealth countries. More recently, the paradigm has shifted towards in-country education delivered by academic staff cognisant with the opportunities and challenges of development in Malawi. There remains, though, a gap between graduate knowledge of the subject and the skills necessary to pursue a professional career in the sector. Although there is no consensus yet on the meaning of employability in the literature, lessons from the project indicate that academic–public–private collaboration helps incorporate in curriculum skills that employers anticipate. Applicability of these principles is however context dependent, particularly in the emerging economy context where institutional capacity may be less developed compared to elsewhere.

  7. Individual-based model for radiation risk assessment

    Science.gov (United States)

    Smirnova, O.

    A mathematical model is developed which enables one to predict the life span probability for mammals exposed to radiation. It relates statistical biometric functions with statistical and dynamic characteristics of an organism's critical system. To calculate the dynamics of the latter, the respective mathematical model is used too. This approach is applied to describe the effects of low level chronic irradiation on mice when the hematopoietic system (namely, thrombocytopoiesis) is the critical one. For identification of the joint model, experimental data on hematopoiesis in nonirradiated and irradiated mice, as well as on mortality dynamics of those in the absence of radiation are utilized. The life span probability and life span shortening predicted by the model agree with corresponding experimental data. Modeling results show the significance of ac- counting the variability of the individual radiosensitivity of critical system cells when estimating the radiation risk. These findings are corroborated by clinical data on persons involved in the elimination of the Chernobyl catastrophe after- effects. All this makes it feasible to use the model for radiation risk assessments for cosmonauts and astronauts on long-term missions such as a voyage to Mars or a lunar colony. In this case the model coefficients have to be determined by making use of the available data for humans. Scenarios for the dynamics of dose accumulation during space flights should also be taken into account.

  8. Estimation of Nonlinear Dynamic Panel Data Models with Individual Effects

    Directory of Open Access Journals (Sweden)

    Yi Hu

    2014-01-01

    Full Text Available This paper suggests a generalized method of moments (GMM based estimation for dynamic panel data models with individual specific fixed effects and threshold effects simultaneously. We extend Hansen’s (Hansen, 1999 original setup to models including endogenous regressors, specifically, lagged dependent variables. To address the problem of endogeneity of these nonlinear dynamic panel data models, we prove that the orthogonality conditions proposed by Arellano and Bond (1991 are valid. The threshold and slope parameters are estimated by GMM, and asymptotic distribution of the slope parameters is derived. Finite sample performance of the estimation is investigated through Monte Carlo simulations. It shows that the threshold and slope parameter can be estimated accurately and also the finite sample distribution of slope parameters is well approximated by the asymptotic distribution.

  9. Individual brain structure and modelling predict seizure propagation.

    Science.gov (United States)

    Proix, Timothée; Bartolomei, Fabrice; Guye, Maxime; Jirsa, Viktor K

    2017-03-01

    See Lytton (doi:10.1093/awx018) for a scientific commentary on this article.Neural network oscillations are a fundamental mechanism for cognition, perception and consciousness. Consequently, perturbations of network activity play an important role in the pathophysiology of brain disorders. When structural information from non-invasive brain imaging is merged with mathematical modelling, then generative brain network models constitute personalized in silico platforms for the exploration of causal mechanisms of brain function and clinical hypothesis testing. We here demonstrate with the example of drug-resistant epilepsy that patient-specific virtual brain models derived from diffusion magnetic resonance imaging have sufficient predictive power to improve diagnosis and surgery outcome. In partial epilepsy, seizures originate in a local network, the so-called epileptogenic zone, before recruiting other close or distant brain regions. We create personalized large-scale brain networks for 15 patients and simulate the individual seizure propagation patterns. Model validation is performed against the presurgical stereotactic electroencephalography data and the standard-of-care clinical evaluation. We demonstrate that the individual brain models account for the patient seizure propagation patterns, explain the variability in postsurgical success, but do not reliably augment with the use of patient-specific connectivity. Our results show that connectome-based brain network models have the capacity to explain changes in the organization of brain activity as observed in some brain disorders, thus opening up avenues towards discovery of novel clinical interventions. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.

  10. Individual-based modeling of fish: Linking to physical models and water quality.

    Energy Technology Data Exchange (ETDEWEB)

    Rose, K.A.

    1997-08-01

    The individual-based modeling approach for the simulating fish population and community dynamics is gaining popularity. Individual-based modeling has been used in many other fields, such as forest succession and astronomy. The popularity of the individual-based approach is partly a result of the lack of success of the more aggregate modeling approaches traditionally used for simulating fish population and community dynamics. Also, recent recognition that it is often the atypical individual that survives has fostered interest in the individual-based approach. Two general types of individual-based models are distribution and configuration. Distribution models follow the probability distributions of individual characteristics, such as length and age. Configuration models explicitly simulate each individual; the sum over individuals being the population. DeAngelis et al (1992) showed that, when distribution and configuration models were formulated from the same common pool of information, both approaches generated similar predictions. The distribution approach was more compact and general, while the configuration approach was more flexible. Simple biological changes, such as making growth rate dependent on previous days growth rates, were easy to implement in the configuration version but prevented simple analytical solution of the distribution version.

  11. Analytical models approximating individual processes: a validation method.

    Science.gov (United States)

    Favier, C; Degallier, N; Menkès, C E

    2010-12-01

    Upscaling population models from fine to coarse resolutions, in space, time and/or level of description, allows the derivation of fast and tractable models based on a thorough knowledge of individual processes. The validity of such approximations is generally tested only on a limited range of parameter sets. A more general validation test, over a range of parameters, is proposed; this would estimate the error induced by the approximation, using the original model's stochastic variability as a reference. This method is illustrated by three examples taken from the field of epidemics transmitted by vectors that bite in a temporally cyclical pattern, that illustrate the use of the method: to estimate if an approximation over- or under-fits the original model; to invalidate an approximation; to rank possible approximations for their qualities. As a result, the application of the validation method to this field emphasizes the need to account for the vectors' biology in epidemic prediction models and to validate these against finer scale models. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Transient modeling/analysis of hyperbolic heat conduction problems employing mixed implicit-explicit alpha method

    Science.gov (United States)

    Tamma, Kumar K.; D'Costa, Joseph F.

    1991-01-01

    This paper describes the evaluation of mixed implicit-explicit finite element formulations for hyperbolic heat conduction problems involving non-Fourier effects. In particular, mixed implicit-explicit formulations employing the alpha method proposed by Hughes et al. (1987, 1990) are described for the numerical simulation of hyperbolic heat conduction models, which involves time-dependent relaxation effects. Existing analytical approaches for modeling/analysis of such models involve complex mathematical formulations for obtaining closed-form solutions, while in certain numerical formulations the difficulties include severe oscillatory solution behavior (which often disguises the true response) in the vicinity of the thermal disturbances, which propagate with finite velocities. In view of these factors, the alpha method is evaluated to assess the control of the amount of numerical dissipation for predicting the transient propagating thermal disturbances. Numerical test models are presented, and pertinent conclusions are drawn for the mixed-time integration simulation of hyperbolic heat conduction models involving non-Fourier effects.

  13. The psychological contract: is the UK National Health Service a model employer?

    Science.gov (United States)

    Fielden, Sandra; Whiting, Fiona

    2007-05-01

    The UK National Health Service (NHS) is facing recruitment challenges that mean it will need to become an 'employer of choice' if it is to continue to attract high-quality employees. This paper reports the findings from a study focusing on allied health professional staff (n = 67), aimed at establishing the expectations of the NHS inherent in their current psychological contract and to consider whether the government's drive to make the NHS a model employer meets those expectations. The findings show that the most important aspects of the psychological contract were relational and based on the investment made in the employment relationship by both parties. The employment relationship was one of high involvement but also one where transactional contract items, such as pay, were still of some importance. Although the degree of employee satisfaction with the relational content of the psychological contract was relatively positive, there was, nevertheless, a mismatch between levels of importance placed on such aspects of the contract and levels of satisfaction, with employees increasingly placing greater emphasis on those items the NHS is having the greatest difficulty providing. Despite this apparent disparity between employee expectation and the fulfilment of those expectations, the overall health of the psychological contract was still high.

  14. Individual acceptance of the biogas innovation: A structural equation model

    International Nuclear Information System (INIS)

    Emmann, Carsten H.; Arens, Ludwig; Theuvsen, Ludwig

    2013-01-01

    The rapid spread of biogas production in Germany has resulted in an increased public debate over this new business branch. Today the production of biogas is much more controversially debated than several years ago. At the same time it could be proven that even among farmers themselves the acceptance of biogas production in some regions is somewhat dampened due to accompanying “collateral damages”. Therefore, the goal of this paper is to identify relevant influencing factors that determine the acceptance of the innovation “biogas” among farmers by applying a causal analysis. Initial results among the five investigated determinants show that not only an individual attitude toward biogas but also the farmers' personal innovativeness strongly and significantly influences an individual's acceptance of the innovation “biogas”. -- Highlights: •Strong expansion of biogas production based on renewable resources in Germany since 2004. •Low acceptance of biogas production in some regions. •Identification of influencing factors that determine the individual acceptance of the biogas innovation among German farmers. •Compared to existing studies, personal innovativeness was taken into account in the causal model. •Results are important for the further expansion of biogas production in Germany as well as in other countries

  15. An individual-based model of rabbit viral haemorrhagic disease on European wild rabbits (Oryctolagus cuniculus)

    Science.gov (United States)

    Fa, John E.; Sharples, Colin M.; Bell, Diana J.; DeAngelis, Donald L.

    2001-01-01

    We developed an individual-based model of Rabbit Viral Hemorrhagic Disease (RVHD) for European wild rabbits (Oryctolagus cuniculus L.), representing up to 1000 rabbits in four hectares. Model output for productivity and recruitment matched published values. The disease was density-dependent and virulence affected outcome. Strains that caused death after several days produced greater overall mortality than strains in which rabbits either died or recovered very quickly. Disease effect also depended on time of year. We also elaborated a larger scale model representing 25 km2 and 100,000+ rabbits, split into a number of grid-squares. This was a more traditional model that did not represent individual rabbits, but employed a system of dynamic equations for each grid-square. Disease spread depended on probability of transmission between neighboring grid-squares. Potential recovery from a major population crash caused by the disease relied on disease virulence and frequency of recurrence. The model's dependence on probability of disease transmission between grid-squares suggests the way that the model represents the spatial distribution of the population affects simulation. Although data on RVHD in Europe are lacking, our models provide a basis for describing the disease in realistic detail and for assessing influence of various social and spatial factors on spread.

  16. Addressing the midwifery workforce crisis: evaluating an employment model for undergraduate midwifery students at a tertiary maternity hospital in Melbourne, Australia.

    Science.gov (United States)

    McLachlan, Helen L; Forster, Della A; Ford, Rachael L; Farrell, Tanya

    2011-12-01

    In Victoria, maternity services are under significant strain due to increased numbers of women giving birth and critical workforce shortages. Hospitals have experienced challenges in adequately staffing maternity units, particularly on postnatal wards. In 2008, a tertiary maternity hospital in Melbourne introduced a model where undergraduate midwifery students were employed as Division 2 nurses (SMW_Div2) (enrolled nurses), to work in the postnatal area only. This study explored the pilot employment model from the perspective of the SMW_Div2 and hospital midwives. A web-based survey was administered to hospital midwives and the SMW_Div2s in the employment model in January 2010. The survey explored the views of midwives and SMW_Div2s regarding the perceived impact of the model on workforce readiness, recruitment and retention, and clinical competence and confidence. Forty-seven of 158 midwives (30%) and five of nine SMW_Div2s employed in the model responded to the survey. Both groups considered the model to have benefits for the organisation, including increased: student workforce readiness; clinical confidence and competence; and organisational loyalty. Both groups also considered that the model would facilitate: workforce recruitment; a teaching and learning culture within the organisation; and enhanced partnerships between students, hospitals and universities. Caution was expressed regarding workload and the need for ongoing support for SMW_Div2s working in the model. SMW_Div2s and midwives were positive about the introduction of the paid employment model at the Women's. The findings are consistent with evaluations of similar programs in the nursing setting. The employment model has potential short and long term individual and organisational advantages, which is important in the context of increasing births and workforce shortages. Progression of such models will be contingent on the collaboration and cooperation of the various stakeholders involved in maternity

  17. Predictive models to determine imagery strategies employed by children to judge hand laterality.

    Science.gov (United States)

    Spruijt, Steffie; Jongsma, Marijtje L A; van der Kamp, John; Steenbergen, Bert

    2015-01-01

    A commonly used paradigm to study motor imagery is the hand laterality judgment task. The present study aimed to determine which strategies young children employ to successfully perform this task. Children of 5 to 8 years old (N = 92) judged laterality of back and palm view hand pictures in different rotation angles. Response accuracy and response duration were registered. Response durations of the trials with a correct judgment were fitted to a-priori defined predictive sinusoid models, representing different strategies to successfully perform the hand laterality judgment task. The first model predicted systematic changes in response duration as a function of rotation angle of the displayed hand. The second model predicted that response durations are affected by biomechanical constraints of hand rotation. If observed data could be best described by the first model, this would argue for a mental imagery strategy that does not involve motor processes to solve the task. The second model reflects a motor imagery strategy to solve the task. In line with previous research, we showed an age-related increase in response accuracy and decrease in response duration in children. Observed data for both back and palm view showed that motor imagery strategies were used to perform hand laterality judgments, but that not all the children use these strategies (appropriately) at all times. A direct comparison of response duration patterns across age sheds new light on age-related differences in the strategies employed to solve the task. Importantly, the employment of the motor imagery strategy for successful task performance did not change with age.

  18. Modeling structured population dynamics using data from unmarked individuals

    Science.gov (United States)

    Grant, Evan H. Campbell; Zipkin, Elise; Thorson, James T.; See, Kevin; Lynch, Heather J.; Kanno, Yoichiro; Chandler, Richard; Letcher, Benjamin H.; Royle, J. Andrew

    2014-01-01

    The study of population dynamics requires unbiased, precise estimates of abundance and vital rates that account for the demographic structure inherent in all wildlife and plant populations. Traditionally, these estimates have only been available through approaches that rely on intensive mark–recapture data. We extended recently developed N-mixture models to demonstrate how demographic parameters and abundance can be estimated for structured populations using only stage-structured count data. Our modeling framework can be used to make reliable inferences on abundance as well as recruitment, immigration, stage-specific survival, and detection rates during sampling. We present a range of simulations to illustrate the data requirements, including the number of years and locations necessary for accurate and precise parameter estimates. We apply our modeling framework to a population of northern dusky salamanders (Desmognathus fuscus) in the mid-Atlantic region (USA) and find that the population is unexpectedly declining. Our approach represents a valuable advance in the estimation of population dynamics using multistate data from unmarked individuals and should additionally be useful in the development of integrated models that combine data from intensive (e.g., mark–recapture) and extensive (e.g., counts) data sources.

  19. Fraud, individuals, and networks: A biopsychosocial model of scientific frauds.

    Science.gov (United States)

    Leistedt, Samuel J; Linkowski, Paul

    2016-03-01

    The problem of fraud, especially scientific fraud, is global and its identification risk is still in its infancy. Based on an in-depth analysis of several financial and scientific fraud trials, the authors propose a new and integrative model of scientific fraud. This model identifies two major levels for committing fraud: (i) at the personal skills level (micro-level) and (ii) at the network skills level (macro-level). Interacting continuously with each other, they form a dynamic, efficient, and integrative system: an integrative model of fraud. The micro-level refers to three factors: (i) personality organization, (ii) social competence, and (iii) the so-called triangle of fraud. The macro-level refers essentially to social network organization and social engineering. Then, the key to understanding and mostly controlling fraud is to consider both the individual and the environment in which they operate. Based on our model, several steps at the micro- and macro-levels can be proposed. Copyright © 2016 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.

  20. Selection of robust variables for transfer of classification models employing the successive projections algorithm.

    Science.gov (United States)

    Milanez, Karla Danielle Tavares Melo; Araújo Nóbrega, Thiago César; Silva Nascimento, Danielle; Galvão, Roberto Kawakami Harrop; Pontes, Márcio José Coelho

    2017-09-01

    Multivariate models have been widely used in analytical problems involving quantitative and qualitative analyzes. However, there are cases in which a model is not applicable to spectra of samples obtained under new experimental conditions or in an instrument not involved in the modeling step. A solution to this problem is the transfer of multivariate models, usually performed using standardization of the spectral responses or enhancement of the robustness of the model. This present paper proposes two new criteria for selection of robust variables for classification transfer employing the successive projections algorithm (SPA). These variables are then used to build models based on linear discriminant analysis (LDA) with low sensitivity with respect to the differences between the responses of the instruments involved. For this purpose, transfer samples are included in the calculation of the cost for each subset of variables under consideration. The proposed methods are evaluated for two case studies involving identification of adulteration of extra virgin olive oil (EVOO) and hydrated ethyl alcohol fuel (HEAF) using UV-Vis and NIR spectroscopy, respectively. In both cases, similar or better classification transfer results (obtained for a test set measured on the secondary instrument) employing the two criteria were obtained in comparison with direct standardization (DS) and piecewise direct standardization (PDS). For the UV-Vis data, both proposed criteria achieved the correct classification rate (CCR) of 85%, while the best CCR obtained for the standardization methods was 81% for DS. For the NIR data, 92.5% of CCR was obtained by both criteria as well as DS. The results demonstrated the possibility of using either of the criteria proposed for building robust models as an alternative to the standardization of spectral responses for transfer of classification. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Dosha brain-types: A neural model of individual differences.

    Science.gov (United States)

    Travis, Frederick T; Wallace, Robert Keith

    2015-01-01

    This paper explores brain patterns associated with the three categories of regulatory principles of the body, mind, and behavior in Ayurveda, called Vata, Pitta, and Kapha dosha. A growing body of research has reported patterns of blood chemistry, genetic expression, physiological states, and chronic diseases associated with each dosha type. Since metabolic and growth factors are controlled by the nervous system, each dosha type should be associated with patterns of functioning of six major areas of the nervous system: The prefrontal cortex, the reticular activating system, the autonomic nervous system, the enteric nervous system, the limbic system, and the hypothalamus. For instance, the prefrontal cortex, which includes the anterior cingulate, ventral medial, and the dorsal lateral cortices, would exhibit a high range of functioning in the Vata brain-type leading to the possibility of being easily overstimulated. The Vata brain-type performs activity quickly. Learns quickly and forgets quickly. Their fast mind gives them an edge in creative problem solving. The Pitta brain-type reacts strongly to all challenges leading to purposeful and resolute actions. They never give up and are very dynamic and goal oriented. The Kapha brain-type is slow and steady leading to methodical thinking and action. They prefer routine and needs stimulation to get going. A model of dosha brain-types could provide a physiological foundation to understand individual differences. This model could help individualize treatment modalities to address different mental and physical dysfunctions. It also could explain differences in behavior seen in clinical as well as in normal populations.

  2. Dosha brain-types: A neural model of individual differences

    Directory of Open Access Journals (Sweden)

    Frederick T Travis

    2015-01-01

    Full Text Available This paper explores brain patterns associated with the three categories of regulatory principles of the body, mind, and behavior in Ayurveda, called Vata, Pitta, and Kapha dosha. A growing body of research has reported patterns of blood chemistry, genetic expression, physiological states, and chronic diseases associated with each dosha type. Since metabolic and growth factors are controlled by the nervous system, each dosha type should be associated with patterns of functioning of six major areas of the nervous system: The prefrontal cortex, the reticular activating system, the autonomic nervous system, the enteric nervous system, the limbic system, and the hypothalamus. For instance, the prefrontal cortex, which includes the anterior cingulate, ventral medial, and the dorsal lateral cortices, would exhibit a high range of functioning in the Vata brain-type leading to the possibility of being easily overstimulated. The Vata brain-type performs activity quickly. Learns quickly and forgets quickly. Their fast mind gives them an edge in creative problem solving. The Pitta brain-type reacts strongly to all challenges leading to purposeful and resolute actions. They never give up and are very dynamic and goal oriented. The Kapha brain-type is slow and steady leading to methodical thinking and action. They prefer routine and needs stimulation to get going. A model of dosha brain-types could provide a physiological foundation to understand individual differences. This model could help individualize treatment modalities to address different mental and physical dysfunctions. It also could explain differences in behavior seen in clinical as well as in normal populations.

  3. ECONOMETRIC MODELING OF GDP BY EMPLOYMENT AND THE VALUE OF TANGIBLE FIXED ASSESTS

    Directory of Open Access Journals (Sweden)

    Cristina BURGHELEA

    2015-04-01

    Full Text Available The economic potential of a country is consistently a primary goal of existence and sustainable development, to ensure the livelihood of all residents, increase living standards. To achieve this major goal rigorous study must be complex to formulate a diagnosis and real economic status and rationale, on the basis of economic and legislative policy decisions, decisions addressing both immediate time horizons as well as longer periods of time. In this context, we analyzed dynamics of GDP according to the dynamics of employment and dynamics of tangible fixed assets of the economy by applying a rigorous econometric modeling methodology.

  4. An Investigation of Self-reported Health-related Productivity Loss in Office Workers and Associations With Individual and Work-related Factors Using an Employer's Perspective

    DEFF Research Database (Denmark)

    Pereira, Michelle Jessica; Johnston, Venerina; Straker, Leon Melville

    2017-01-01

    OBJECTIVE: Office workers have a high prevalence of musculoskeletal conditions. This can be a significant economic burden due to health-related productivity loss. Individual and work-related factors related to office worker health-related productivity were investigated. METHODS: A survey including...... the Health and Work Performance Questionnaire, which estimated productivity loss, also recorded individual and work-related factors with potential associations with health-related productivity. Muscle function and workstation ergonomics were examined through physical assessments. Linear models investigated...... the relationships between these factors and health-related productivity. RESULTS: Significant factors identified were occupational category (0.001 Health-related productivity loss was greater...

  5. Off-the-job training for VATS employing anatomically correct lung models.

    Science.gov (United States)

    Obuchi, Toshiro; Imakiire, Takayuki; Miyahara, Sou; Nakashima, Hiroyasu; Hamanaka, Wakako; Yanagisawa, Jun; Hamatake, Daisuke; Shiraishi, Takeshi; Moriyama, Shigeharu; Iwasaki, Akinori

    2012-02-01

    We evaluated our simulated major lung resection employing anatomically correct lung models as "off-the-job training" for video-assisted thoracic surgery trainees. A total of 76 surgeons voluntarily participated in our study. They performed video-assisted thoracic surgical lobectomy employing anatomically correct lung models, which are made of sponges so that vessels and bronchi can be cut using usual surgical techniques with typical forceps. After the simulation surgery, participants answered questionnaires on a visual analogue scale, in terms of their level of interest and the reality of our training method as off-the-job training for trainees. We considered that the closer a score was to 10, the more useful our method would be for training new surgeons. Regarding the appeal or level of interest in this simulation surgery, the mean score was 8.3 of 10, and regarding reality, it was 7.0. The participants could feel some of the real sensations of the surgery and seemed to be satisfied to perform the simulation lobectomy. Our training method is considered to be suitable as an appropriate type of surgical off-the-job training.

  6. Tension at the borders: perceptions of role overload, conflict, strain and facilitation in work, family and health roles among employed individuals with arthritis.

    Science.gov (United States)

    Gignac, Monique A M; Backman, Catherine L; Kaptein, Simone; Lacaille, Diane; Beaton, Dorcas E; Hofstetter, Catherine; Badley, Elizabeth M

    2012-02-01

    To examine inter-relationships among arthritis (A), work (W) and personal life (P) roles and their reciprocal influences, especially experiences of role balance/imbalance among individuals with inflammatory arthritis (IA) and OA. Eight focus groups were conducted with 24 women and 16 men (aged 29-72 years). A purposive sample was recruited from community advertising. Eligibility included current employment or having been employed within the previous year. Participants were asked about ways arthritis, work and personal life roles intersected and their impact. A standardized questionnaire collected demographic, symptom and employment data for descriptive purposes. Participants noted that having arthritis affected their identity and intersected with work and personal roles, creating role overload, role conflict, role strain and role facilitation. Role overload highlighted that arthritis both affected and was impacted by work and personal life (A → W; A → P; W → A; P → A). Role conflict focused on A → W and A → P difficulties, whereas role facilitation emphasized the positive impact of work and personal life roles on arthritis (W → A; P → A). Role strain was pervasive and arose from numerous sources. Personal strategies (e.g. positive framing) and contextual factors (e.g. support) were important in contributing to or ameliorating role balance/imbalance. By comprehensively examining multiple types of role balance/imbalance and the context within which it occurs, this study identifies gaps in patient-oriented measurement of the impact of arthritis and areas of need in the development of arthritis intervention.

  7. Individualized Risk Model for Venous Thromboembolism After Total Joint Arthroplasty.

    Science.gov (United States)

    Parvizi, Javad; Huang, Ronald; Rezapoor, Maryam; Bagheri, Behrad; Maltenfort, Mitchell G

    2016-09-01

    Venous thromboembolism (VTE) after total joint arthroplasty (TJA) is a potentially fatal complication. Currently, a standard protocol for postoperative VTE prophylaxis is used that makes little distinction between patients at varying risks of VTE. We sought to develop a simple scoring system identifying patients at higher risk for VTE in whom more potent anticoagulation may need to be administered. Utilizing the National Inpatient Sample data, 1,721,806 patients undergoing TJA were identified, among whom 15,775 (0.9%) developed VTE after index arthroplasty. Among the cohort, all known potential risk factors for VTE were assessed. An initial logistic regression model using potential predictors for VTE was performed. Predictors with little contribution or poor predictive power were pruned from the data, and the model was refit. After pruning of variables that had little to no contribution to VTE risk, using the logistic regression, all independent predictors of VTE after TJA were identified in the data. Relative weights for each factor were determined. Hypercoagulability, metastatic cancer, stroke, sepsis, and chronic obstructive pulmonary disease had some of the highest points. Patients with any of these conditions had risk for postoperative VTE that exceeded the 3% rate. Based on the model, an iOS (iPhone operating system) application was developed (VTEstimator) that could be used to assign patients into low or high risk for VTE after TJA. We believe individualization of VTE prophylaxis after TJA can improve the efficacy of preventing VTE while minimizing untoward risks associated with the administration of anticoagulation. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Toward an Integrated Competence-Based System Supporting Lifelong Learning and Employability: Concepts, Model, and Challenges

    Science.gov (United States)

    Miao, Yongwu; van der Klink, Marcel; Boon, Jo; Sloep, Peter; Koper, Rob

    Efficient and effective lifelong learning requires that people can make informed decisions about their continuous personal development in the different stages of their life. In this paper we state that lifelong learners need to be characterized as decision-makers. In order to improve the quality of their decisions, we propose the development of an integrated lifelong learning and employment support system, which traces learners’ competence development and provides a decision support environment. An abstract conceptual model has been developed and the main design ideas have been documented using Z notation. Moreover, we analyzed the main technical challenges for the realization of the target system: competence information fusion, decision analysis models, spatial indexing structures and browsing structures and visualization of competence-related information objects.

  9. Changes in the nature and intensity of stress following employment among people with severe mental illness receiving individual placement and support services: an exploratory qualitative study.

    Science.gov (United States)

    Besse, Christine; Poremski, Daniel; Laliberté, Vincent; Latimer, Eric

    2017-08-01

    Most people with severe mental illness (SMI) want to work. Individual placement and support (IPS) programs have proven effective in helping them obtain and keep competitive jobs. Yet, practitioners often fear that competitive jobs might be too stressful. To explore how the nature and intensity of stress experienced by IPS clients changed after the transition from looking for work to being employed. Semi-structured interviews explored the experiences of 16 clients of an IPS program who had recently been competitively employed. Grounded theory was used to structure the analysis. Most participants reported that their stress level decreased once they found work. Stress following work was associated with fear of failure, pressure to perform and uncertainty. The support that people perceived in their return-to-work project, and where they were on their recovery journey, modulated their perception of stress. Many cited IPS as a source of support. Competitive work changed the nature of stress and was mostly associated with a decrease in stress level. Adjunctive interventions aiming to buffer self-stigma or help participants use more adaptive coping mechanisms may merit investigation.

  10. Developments in convective heat transfer models featuring seamless and selected detail surfaces, employing electroless plating

    Science.gov (United States)

    Stalmach, C. J., Jr.

    1975-01-01

    Several model/instrument concepts employing electroless metallic skin were considered for improvement of surface condition, accuracy, and cost of contoured-geometry convective heat transfer models. A plated semi-infinite slab approach was chosen for development and evaluation in a hypersonic wind tunnel. The plated slab model consists of an epoxy casting containing fine constantan wires accurately placed at specified surface locations. An electroless alloy was deposited on the plastic surface that provides a hard, uniformly thick, seamless skin. The chosen alloy forms a high-output thermocouple junction with each exposed constantan wire, providing means of determining heat transfer during tunnel testing of the model. A selective electroless plating procedure was used to deposit scaled heatshield tiles on the lower surface of a 0.0175-scale shuttle orbiter model. Twenty-five percent of the tiles were randomly selected and plated to a height of 0.001-inch. The purpose was to assess the heating effects of surface roughness simulating misalignment of tiles that may occur during manufacture of the spacecraft.

  11. An Investigation of Self-reported Health-related Productivity Loss in Office Workers and Associations With Individual and Work-related Factors Using an Employer's Perspective.

    Science.gov (United States)

    Pereira, Michelle Jessica; Johnston, Venerina; Straker, Leon Melville; Sjøgaard, Gisela; Melloh, Markus; O'Leary, Shaun Patrick; Comans, Tracy Anne

    2017-07-01

    Office workers have a high prevalence of musculoskeletal conditions. This can be a significant economic burden due to health-related productivity loss. Individual and work-related factors related to office worker health-related productivity were investigated. A survey including the Health and Work Performance Questionnaire, which estimated productivity loss, also recorded individual and work-related factors with potential associations with health-related productivity. Muscle function and workstation ergonomics were examined through physical assessments. Linear models investigated the relationships between these factors and health-related productivity. Significant factors identified were occupational category (0.001 productivity loss was greater in office workers working as managers, with lower job satisfaction and psychological wellbeing, and those with musculoskeletal pain. Office worker health-related productivity loss is represented by a combination of both individual and work-related factors.

  12. Explorations in combining cognitive models of individuals and system dynamics models of groups.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.

    2008-07-01

    This report documents a demonstration model of interacting insurgent leadership, military leadership, government leadership, and societal dynamics under a variety of interventions. The primary focus of the work is the portrayal of a token societal model that responds to leadership activities. The model also includes a linkage between leadership and society that implicitly represents the leadership subordinates as they directly interact with the population. The societal model is meant to demonstrate the efficacy and viability of using System Dynamics (SD) methods to simulate populations and that these can then connect to cognitive models depicting individuals. SD models typically focus on average behavior and thus have limited applicability to describe small groups or individuals. On the other hand, cognitive models readily describe individual behavior but can become cumbersome when used to describe populations. Realistic security situations are invariably a mix of individual and population dynamics. Therefore, the ability to tie SD models to cognitive models provides a critical capability that would be otherwise be unavailable.

  13. The Anglo-Saxon model of employment in the current economic context. The case of United Kingdom

    OpenAIRE

    Mirela Ionela ACELEANU

    2012-01-01

    The Anglo-Saxon model of employment has certain features that derive from the specificity of the political and economic system of Great Britain. The labour market policies in the United Kingdom were different depending on the historical and political period; however, the Anglo-Saxon model is characterized mainly by high flexibility but low security. This paper presents the main features of the Anglo-Saxon model of employment, compared to the Nordic and the Mediterranean m...

  14. Getting unemployed job seekers back to work: the development of a process model of employment counseling behavior

    NARCIS (Netherlands)

    Noordzij, G.; van Hooft, E.A.J.; van Mierlo, H.; van Dam, A.; Born, M.Ph.

    2013-01-01

    The aim of this study was to propose a tentative model of employment counseling based on 31 critical incident interviews with supervisors, employment counselors, and unemployed job seekers. The incidents (N= 599) mentioned in the interviews were inductively used to develop a category framework

  15. Increasing Employability by Implementing a Work-Integrated Learning Partnership Model in South Africa--A Student Perspective

    Science.gov (United States)

    Taylor, Susanne; Govender, Cookie M.

    2017-01-01

    In South Africa, 70 per cent of the population is under 35 years old. South Africa has a vision to increase youth employment by focusing on education, training and skills development that will promote employment opportunities. A work-integrated learning (WIL) partnership model was developed to provide students with work experience and to increase…

  16. Re-engineering pre-employment check-up systems: a model for improving health services.

    Science.gov (United States)

    Rateb, Said Abdel Hakim; El Nouman, Azza Abdel Razek; Rateb, Moshira Abdel Hakim; Asar, Mohamed Naguib; El Amin, Ayman Mohammed; Gad, Saad abdel Aziz; Mohamed, Mohamed Salah Eldin

    2011-01-01

    The purpose of this paper is to develop a model for improving health services provided by the pre-employment medical fitness check-up system affiliated to Egypt's Health Insurance Organization (HIO). Operations research, notably system re-engineering, is used in six randomly selected centers and findings before and after re-engineering are compared. The re-engineering model follows a systems approach, focusing on three areas: structure, process and outcome. The model is based on six main components: electronic booking, standardized check-up processes, protected medical documents, advanced archiving through an electronic content management (ECM) system, infrastructure development, and capacity building. The model originates mainly from customer needs and expectations. The centers' monthly customer flow increased significantly after re-engineering. The mean time spent per customer cycle improved after re-engineering--18.3 +/- 5.5 minutes as compared to 48.8 +/- 14.5 minutes before. Appointment delay was also significantly decreased from an average 18 to 6.2 days. Both beneficiaries and service providers were significantly more satisfied with the services after re-engineering. The model proves that re-engineering program costs are exceeded by increased revenue. Re-engineering in this study involved multiple structure and process elements. The literature review did not reveal similar re-engineering healthcare packages. Therefore, each element was compared separately. This model is highly recommended for improving service effectiveness and efficiency. This research is the first in Egypt to apply the re-engineering approach to public health systems. Developing user-friendly models for service improvement is an added value.

  17. Predictive models for the assessment of occupational exposure to chemicals: A new challenge for employers

    Directory of Open Access Journals (Sweden)

    Jan Piotr Gromiec

    2013-10-01

    Full Text Available Employers are obliged to carry out and document the risk associated with the use of chemical substances. The best but the most expensive method is to measure workplace concentrations of chemicals. At present no "measureless" method for risk assessment is available in Poland, but predictive models for such assessments have been developed in some countries. The purpose of this work is to review and evaluate the applicability of selected predictive methods for assessing occupational inhalation exposure and related risk to check the compliance with Occupational Exposure Limits (OELs, as well as the compliance with REACH obligations. Based on the literature data HSE COSHH Essentials, EASE, ECETOC TRA, Stoffenmanager, and EMKG-Expo-Tool were evaluated. The data on validation of predictive models were also examined. It seems that predictive models may be used as a useful method for Tier 1 assessment of occupational exposure by inhalation. Since the levels of exposure are frequently overestimated, they should be considered as "rational worst cases" for selection of proper control measures. Bearing in mind that the number of available exposure scenarios and PROC categories is limited, further validation by field surveys is highly recommended. Predictive models may serve as a good tool for preliminary risk assessment and selection of the most appropriate risk control measures in Polish small and medium size enterprises (SMEs providing that they are available in the Polish language. This also requires an extensive training of their future users. Med Pr 2013;64(5:699–716

  18. An integrative model for measuring graduates’ employability skills—A study in China

    OpenAIRE

    Wenping Su; Miao Zhang

    2015-01-01

    Employability is a key issue in graduates’ job-hunting, but little research has been done on that of the graduates in Chinese universities. These universities have been experiencing a decline in their graduate employment since the past decade. This paper attempts to tackle this issue. It reviews the relevant research on employability and develops a research-based theoretical framework to evaluate and analyze the graduates’ employability in China. It adopts multiple approaches to establish the...

  19. Fuzzy clustering: critical analysis of the contextual mechanisms employed by three neural network models

    Science.gov (United States)

    Baraldi, Andrea; Parmiggiani, Flavio

    1996-06-01

    According to the following definition, taken from the literature, a fuzzy clustering mechanism allows the same input pattern to belong to multiple categories to different degrees. Many clustering neural network (NN) models claim to feature fuzzy properties, but several of them (like the Fuzzy ART model) do not satisfy this definition. Vice versa, we believe that Kohonen's Self-Organizing Map, SOM, satisfies the definition provided above, even though this NN model is well-known to (robustly) perform topologically ordered mapping rather than fuzzy clustering. This may sound as a paradox if we consider that several fuzzy NN models (such as the Fuzzy Learning Vector Quantization, FLVQ, which was first called Fuzzy Kohonen Clustering Network, FKCN) were originally developed to enhance Kohonen's models (such as SOM and the vector quantization model, VQ). The fuzziness of SOM indicates that a network of processing elements (PEs) can verify the fuzzy clustering definition when it exploits local rules which are biologically plausible (such as the Kohonen bubble strategy). This is equivalent to state that the exploitation of the fuzzy set theory in the development of complex systems (e.g., clustering NNs) may provide new mathematical tools (e.g., the definition of membership function) to simulate the behavior of those cooperative/competitive mechanisms already identified by neurophysiological studies. When a biologically plausible cooperative/competitive strategy is pursued effectively, neighboring PEs become mutually coupled to gain sensitivity to contextual effects. PEs which are mutually coupled are affected by vertical (inter-layer) as well as horizontal (intra-layer) connections. To summarize, we suggest to relate the study of fuzzy clustering mechanisms to the multi-disciplinary science of complex systems, with special regard to the investigation of the cooperative/competitive local rules employed by complex systems to gain sensitivity to contextual effects in

  20. Employing Organizational Modeling and Simulation to Reduce F/A-18E/F F414 Engine Maintenance Time

    National Research Council Canada - National Science Library

    Hagan, Joel J; Slack, William G

    2006-01-01

    ...) at Naval Air Station (NAS) Lemoore, California. To achieve this goal, organizational modeling was employed to evaluate how changes to the organizational structure of the Lemoore AIMD affected engine throughput time...

  1. THE WORLD-MODELLING POTENCY OF THE INDIVIDUAL METAPHOR

    Directory of Open Access Journals (Sweden)

    Pavlova, M.S.

    2016-03-01

    Full Text Available This article analyzes individual metaphors as a fundamental component of the artistic worldview. The research discusses the correlation between the individual metaphor and interdiscourse markedness that allows identifying some peculiarities of cultural identity of the English-language literary text. The central place belongs to the propositions connected with the ways of reality conceptualization in the minds of the English-speaking mentality, which are necessary for correct interpretation of the cultural-specific information.

  2. Full experimental modelling of a liver tissue mimicking phantom for medical ultrasound studies employing different hydrogels.

    Science.gov (United States)

    Casciaro, Sergio; Conversano, Francesco; Musio, Stefano; Casciaro, Ernesto; Demitri, Christian; Sannino, Alessandro

    2009-04-01

    Tissue mimicking phantoms have been widely reported to be an important tool for development, optimisation and performance testing of ultrasound-based diagnostic techniques. In particular, modern applications of tissue mimicking phantoms often include characterisation of the nonlinear behaviour of experimental ultrasound contrast agents. In such cases, the tissue-mimicking materials should be chosen not only based on the values of their density, speed of sound and attenuation coefficient, but also considering their effect on the appearance of "native harmonics" due to nonlinear distortion of ultrasound signal during propagation. In a previous paper it was demonstrated that a cellulose-based hydrogel is suitable to simulate nonlinear acoustical behaviour of liver tissue for thicknesses up to 8 cm. In this paper we present the experimental characterisation of the nonlinear acoustical behaviour of a different polyethylene glycol diacrylate (PEGDA)-based hydrogel, in order to assess whether and how it can improve the performances and overcome some limitations of the cellulose-based hydrogel as liver tissue-mimicking material. Samples of pig liver tissue, cellulose-based hydrogel and PEGDA-based hydrogel were insonified in a through-transmission set-up, employing 2.25-MHz pulses with different mechanical index (MI) values. Second harmonic and first harmonic amplitudes were extracted from the spectra of received signals and their difference was then used to compare sample behaviours. Obtained results show how a new more accurate and combined experimental model of linear and nonlinear acoustical behaviour of liver tissue is feasible. In fact, a further confirmation of the cellulose-based hydrogel effectiveness to precisely simulate the liver tissue for penetration depths up to 8 cm was provided, and it was also shown that the employment of the PEGDA-based hydrogel can extend the range of useful tissue-mimicking material thicknesses up to 11 cm, moreover allowing a

  3. Comparing observed and modelled growth of larval herring (Clupea harengusz: Testing individual-based model parameterisations

    Directory of Open Access Journals (Sweden)

    Helena M. Hauss

    2009-10-01

    Full Text Available Experiments that directly test larval fish individual-based model (IBM growth predictions are uncommon since it is difficult to simultaneously measure all relevant metabolic and behavioural attributes. We compared observed and modelled somatic growth of larval herring (Clupea harengus in short-term (50 degree-day laboratory trials conducted at 7 and 13°C in which larvae were either unfed or fed ad libitum on different prey sizes (~100 to 550 µm copepods, Acartia tonsa. The larval specific growth rate (SGR, % DW d-1 was generally overestimated by the model, especially for larvae foraging on large prey items. Model parameterisations were adjusted to explore the effect of 1 temporal variability in foraging of individuals, and 2 reduced assimilation efficiency due to rapid gut evacuation at high feeding rates. With these adjustments, the model described larval growth well across temperatures, prey sizes, and larval sizes. Although the experiments performed verified the growth model, variability in growth and foraging behaviour among larvae shows that it is necessary to measure both the physiology and feeding behaviour of the same individual. This is a challenge for experimentalists but will ultimately yield the most valuable data to adequately model environmental impacts on the survival and growth of marine fish early life stages.

  4. Epilepsy and employment: literature review.

    Science.gov (United States)

    Smeets, Vivian M J; van Lierop, Brigitte A G; Vanhoutvin, Jos P G; Aldenkamp, Albert P; Nijhuis, Frans J N

    2007-05-01

    The aim of this review is to increase understanding of the factors that affect the regular employment positions of people with epilepsy by means of the World Health Organization International Classification of Functioning, Disability, and Health (ICF) model. Thirty-four primary research articles describing factors associated with employment for people with epilepsy are reviewed. People with epilepsy may face a number of complex and interacting problems in finding and maintaining employment. Stigma, seizure severity, and psychosocial variables such as low self-esteem, passive coping style, and low self-efficacy have been implicated as factors that play an important role in predicting employment. Findings demonstrate the need for specific employment training programs. We recommend specific training interventions that focus on increasing the self-efficacy and coping skills of people with epilepsy so that these individuals will be able to accept their disorder and make personal and health-related choices that help them to achieve better employment positions in society.

  5. The impact of supported employment and working on clinical and social functioning: results of an international study of individual placement and support.

    Science.gov (United States)

    Burns, Tom; Catty, Jocelyn; White, Sarah; Becker, Thomas; Koletsi, Marsha; Fioritti, Angelo; Rössler, Wulf; Tomov, Toma; van Busschbach, Jooske; Wiersma, Durk; Lauber, Christoph

    2009-09-01

    Concerns are frequently expressed that working might worsen the mental health of people with severe mental illness (SMI). Several studies of Individual Placement and Support (IPS), however, have found associations between working and better nonvocational outcomes. IPS has been found to double the return to work of people with SMI in 6 European countries. To explore separately associations between IPS, returning to work, and clinical and social outcomes. Patients (n = 312) in a randomized controlled trial of IPS in 6 European centers were followed up for 18 months. There were no differences in clinical and social functioning between IPS and control patients at 18 months. Those who worked had better global functioning, fewer symptoms, and less social disability at final follow-up; greater job tenure was associated with better functioning. Working was associated with concurrently better clinical and social functioning, but this contrast was stronger in the control group, suggesting that IPS was better than the control service at helping more unwell patients into work. Working was associated with having been in remission and out of hospital for the previous 6 months. It was also associated with a slight decrease in depression and with being in remission over the subsequent 6 months. Concerns among clinicians about possible detrimental effects of working and supported employment have been misplaced. Although some of the associations found may have been selection effects, there is sufficient evidence of work having beneficial effects on clinical and social functioning to merit further exploration.

  6. Variation in Primary Cesarean Delivery Rates by Individual Physician within a Single Hospital Laborist Model

    Science.gov (United States)

    METZ, Torri D.; ALLSHOUSE, Amanda A.; GILBERT, Sara A Babcock; DOYLE, Reina; TONG, Angie; CAREY, J. Christopher

    2016-01-01

    Background Laborist practice models are associated with lower cesarean delivery rates than individual private practice models in several studies; however, this effect is not uniform. Further exploration of laborist models may help us better understand the observed reduction in cesarean delivery rates in some hospitals with implementation of a laborist model. Objective Our objective was to evaluate the degree of variation in primary cesarean delivery rates by individual laborists within a single institution employing a laborist model. In addition, we sought to evaluate whether differences in cesarean delivery rates resulted in different maternal or short-term neonatal outcomes. Study Design At this teaching institution, one laborist (either a generalist or maternal-fetal medicine attending physician) is directly responsible for labor and delivery management during each shift. No patients are followed in a private practice model nor are physicians incentivized to perform deliveries. We retrospectively identified all laborists who delivered nulliparous, term women with cephalic singletons at this institution from 2007-14. Overall and individual primary cesarean delivery rates were reported as percentages with exact Pearson 95% CI. Laborists were grouped by tertile as having low, medium or high cesarean delivery rates. Characteristics of the women delivered, indications for cesarean delivery, and short-term neonatal outcomes were compared between these groups. A binomial regression model of cesarean delivery was estimated, where the relative rates of each laborist compared to the lowest-unadjusted laborist rate were calculated; a second model was estimated to adjust for patient-level maternal characteristics. Results Twenty laborists delivered 2,224 nulliparous, term women with cephalic singletons. The overall cesarean delivery rate was 24.1% (95% CI 21.4-26.8). In an unadjusted binomial model, the overall effect of individual laborist was significant (pcesarean

  7. The Anglo-Saxon model of employment in the current economic context. The case of United Kingdom

    Directory of Open Access Journals (Sweden)

    Mirela Ionela ACELEANU

    2012-11-01

    Full Text Available The Anglo-Saxon model of employment has certain features that derive from the specificity of the political and economic system of Great Britain. The labour market policies in the United Kingdom were different depending on the historical and political period; however, the Anglo-Saxon model is characterized mainly by high flexibility but low security. This paper presents the main features of the Anglo-Saxon model of employment, compared to the Nordic and the Mediterranean model and shows Britain's economic situation before and after the crisis.

  8. Building aggregate timber supply models from individual harvest choice

    Science.gov (United States)

    Maksym Polyakov; David N. Wear; Robert Huggett

    2009-01-01

    Timber supply has traditionally been modelled using aggregate data. In this paper, we build aggregate supply models for four roundwood products for the US state of North Carolina from a stand-level harvest choice model applied to detailed forest inventory. The simulated elasticities of pulpwood supply are much lower than reported by previous studies. Cross price...

  9. Experimental validation of convection-diffusion discretisation scheme employed for computational modelling of biological mass transport

    Directory of Open Access Journals (Sweden)

    Ku David N

    2010-07-01

    Full Text Available Abstract Background The finite volume solver Fluent (Lebanon, NH, USA is a computational fluid dynamics software employed to analyse biological mass-transport in the vasculature. A principal consideration for computational modelling of blood-side mass-transport is convection-diffusion discretisation scheme selection. Due to numerous discretisation schemes available when developing a mass-transport numerical model, the results obtained should either be validated against benchmark theoretical solutions or experimentally obtained results. Methods An idealised aneurysm model was selected for the experimental and computational mass-transport analysis of species concentration due to its well-defined recirculation region within the aneurysmal sac, allowing species concentration to vary slowly with time. The experimental results were obtained from fluid samples extracted from a glass aneurysm model, using the direct spectrophometric concentration measurement technique. The computational analysis was conducted using the four convection-diffusion discretisation schemes available to the Fluent user, including the First-Order Upwind, the Power Law, the Second-Order Upwind and the Quadratic Upstream Interpolation for Convective Kinetics (QUICK schemes. The fluid has a diffusivity of 3.125 × 10-10 m2/s in water, resulting in a Peclet number of 2,560,000, indicating strongly convection-dominated flow. Results The discretisation scheme applied to the solution of the convection-diffusion equation, for blood-side mass-transport within the vasculature, has a significant influence on the resultant species concentration field. The First-Order Upwind and the Power Law schemes produce similar results. The Second-Order Upwind and QUICK schemes also correlate well but differ considerably from the concentration contour plots of the First-Order Upwind and Power Law schemes. The computational results were then compared to the experimental findings. An average error of 140

  10. Experimental validation of convection-diffusion discretisation scheme employed for computational modelling of biological mass transport.

    Science.gov (United States)

    Carroll, Gráinne T; Devereux, Paul D; Ku, David N; McGloughlin, Timothy M; Walsh, Michael T

    2010-07-19

    The finite volume solver Fluent (Lebanon, NH, USA) is a computational fluid dynamics software employed to analyse biological mass-transport in the vasculature. A principal consideration for computational modelling of blood-side mass-transport is convection-diffusion discretisation scheme selection. Due to numerous discretisation schemes available when developing a mass-transport numerical model, the results obtained should either be validated against benchmark theoretical solutions or experimentally obtained results. An idealised aneurysm model was selected for the experimental and computational mass-transport analysis of species concentration due to its well-defined recirculation region within the aneurysmal sac, allowing species concentration to vary slowly with time. The experimental results were obtained from fluid samples extracted from a glass aneurysm model, using the direct spectrophometric concentration measurement technique. The computational analysis was conducted using the four convection-diffusion discretisation schemes available to the Fluent user, including the First-Order Upwind, the Power Law, the Second-Order Upwind and the Quadratic Upstream Interpolation for Convective Kinetics (QUICK) schemes. The fluid has a diffusivity of 3.125 x 10-10 m2/s in water, resulting in a Peclet number of 2,560,000, indicating strongly convection-dominated flow. The discretisation scheme applied to the solution of the convection-diffusion equation, for blood-side mass-transport within the vasculature, has a significant influence on the resultant species concentration field. The First-Order Upwind and the Power Law schemes produce similar results. The Second-Order Upwind and QUICK schemes also correlate well but differ considerably from the concentration contour plots of the First-Order Upwind and Power Law schemes. The computational results were then compared to the experimental findings. An average error of 140% and 116% was demonstrated between the experimental

  11. A Latent Markov Model with Covariates to Study Unobserved Heterogeneity among Fertility Patterns of Couples Employing Natural Family Planning Methods

    Directory of Open Access Journals (Sweden)

    Fulvia Pennoni

    2017-08-01

    Full Text Available PurposeWe use the historical data from the European Study of Daily Fecundability and we develop an algorithm to determine the fertile window in a woman’s cycle according to the rules of the C.A.Me.N. symptothermal method proposed by the Centro Ambrosiano Metodi Naturali. Our aim is to identify variables acting on the probability of conception by considering the fertile window and factors that cannot be explained by employing the observed covariates of individuals and couples.MethodsWe adopt the latent Markov model with covariates tailored for data collected at times when a latent process detects the dependence across fertile periods of each woman’s cycle. We consider measurement errors, transitions between conception and non-conception, and the prediction of conception rate over the fertile windows.ConclusionWe find that the conception pattern is mainly related to sexual intercourse behavior during the fertile window and to previous pregnancies. For the cohort under study, we predict a steep decline in the average conception rate across fertile windows.

  12. A watershed model of individual differences in fluid intelligence.

    Science.gov (United States)

    Kievit, Rogier A; Davis, Simon W; Griffiths, John; Correia, Marta M; Cam-Can; Henson, Richard N

    2016-10-01

    Fluid intelligence is a crucial cognitive ability that predicts key life outcomes across the lifespan. Strong empirical links exist between fluid intelligence and processing speed on the one hand, and white matter integrity and processing speed on the other. We propose a watershed model that integrates these three explanatory levels in a principled manner in a single statistical model, with processing speed and white matter figuring as intermediate endophenotypes. We fit this model in a large (N=555) adult lifespan cohort from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) using multiple measures of processing speed, white matter health and fluid intelligence. The model fit the data well, outperforming competing models and providing evidence for a many-to-one mapping between white matter integrity, processing speed and fluid intelligence. The model can be naturally extended to integrate other cognitive domains, endophenotypes and genotypes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Analysis of thermoluminescence kinetics of Mg2SiO4:Tb compounds employing an interactive model

    International Nuclear Information System (INIS)

    Marcazzo, J.; Prokic, M.; Santiago, M.; Molina, P.; Caselli, E.

    2009-01-01

    The kinetics involved in the thermoluminescence (TL) of Mg 2 SiO 4 :Tb compounds has been investigated by unfolding glow curves employing both the General Order model and a model that takes into account interactions among traps. The dependence of the glow curve shape on dose is only correctly described if interaction among traps is included in the analysis.

  14. Departure time choice: Modelling individual preferences, intention and constraints

    DEFF Research Database (Denmark)

    Thorhauge, Mikkel

    to change their departure time rather than changing their transport mode to avoid congestion (Hendrickson and Planke, 1984; SACTRA, 1994; Kroes et al., 1996; Hess et al., 2007a). Hence, understanding the departure time choice from an individual perspective is important to develop policies aimed to address...... working hours) as the penalty of late arrival is very likely to be higher for individuals with constraints on arrival time. However, flexibility is not only a matter of fixed arrival time. Activities can be mandatory or discretionary (Yamamoto and Kitamura, 1999), performed alone or jointly with family...... departure time. Parallel with the micro-economic theory, the psychology literature has evidenced that individuals’ behaviours are driven by underlying latent constructs, such as attitude, norms and perceptions. In the past decades, more attention has been given to incorporate and understand underlying...

  15. Job crafting: Towards a new model of individual job redesign

    Directory of Open Access Journals (Sweden)

    Maria Tims

    2010-12-01

    Research purpose: The purpose of the study was to fit job crafting in job design theory. Motivation for the study: The study was an attempt to shed more light on the types of proactive behaviours of individual employees at work. Moreover, we explored the concept of job crafting and its antecedents and consequences. Research design, approach and method: A literature study was conducted in which the focus was first on proactive behaviour of the employee and then on job crafting. Main findings: Job crafting can be seen as a specific form of proactive behaviour in which the employee initiates changes in the level of job demands and job resources. Job crafting may be facilitated by job and individual characteristics and may enable employees to fit their jobs to their personal knowledge, skills and abilities on the one hand and to their preferences and needs on the other hand. Practical/managerial implications: Job crafting may be a good way for employees to improve their work motivation and other positive work outcomes. Employees could be encouraged to exert more influence on their job characteristics. Contribution/value-add: This article describes a relatively new perspective on active job redesign by the individual, called job crafting, which has important implications for job design theories.

  16. Adapting the Individual Placement and Support Model with Homeless Young Adults

    Science.gov (United States)

    Ferguson, Kristin M.; Xie, Bin; Glynn, Shirley

    2012-01-01

    Background: Prior research reveals high unemployment rates among homeless young adults. The literature offers many examples of using evidence-based supported employment models with vulnerable populations to assist them in obtaining and maintaining competitive employment; yet few examples exist to date with homeless young adults with mental…

  17. [Relationship between two models of personality in old individuals].

    Science.gov (United States)

    Calvet, Benjamin; Bricaud, Magali; Clément, Jean-Pierre

    2014-12-01

    The relationships between the seven dimensions of the Cloninger psychobiological model and the five factors of the Costa and McCrae model were examined in 54 elderly subjects from the French general population. The dimensions of temperament (novelty seeking, harm avoidance, reward dependence) and character (determination, cooperation, transcendence) from the Cloninger's model were measured by the temperament and character inventory whereas the five factors of Costa and McCrae model (neuroticism, extraversion, openness to experience, agreeableness and conscientiousness) were evaluated using the NEO PI-R. Multiple regression analyses show that some dimensions of the temperament and character inventory predict some dimensions of the Big five and vice versa. Therefore we suggest that the Big five model could be related to brain monoaminergic activities.

  18. Individual discriminative face recognition models based on subsets of features

    DEFF Research Database (Denmark)

    Clemmensen, Line Katrine Harder; Gomez, David Delgado; Ersbøll, Bjarne Kjær

    2007-01-01

    The accuracy of data classification methods depends considerably on the data representation and on the selected features. In this work, the elastic net model selection is used to identify meaningful and important features in face recognition. Modelling the characteristics which distinguish one...... selection techniques such as forward selection or lasso regression become inadequate. In the experimental section, the performance of the elastic net model is compared with geometrical and color based algorithms widely used in face recognition such as Procrustes nearest neighbor, Eigenfaces, or Fisher...

  19. Individualized Human CAD Models: Anthropmetric Morphing and Body Tissue Layering

    Science.gov (United States)

    2014-07-31

    Part Flow Chart of the Interaction among VBA Macros, Excel® Spreadsheet, and SolidWorks Front View of the Male and Female Soldier CAD Model...yellow highlighting. The spreadsheet is linked to the CAD model by macros created with the Visual Basic for Application ( VBA ) editor in Microsoft Excel...basically three working parts to the anthropometric morphing that are all interconnected ( VBA macros, Excel spreadsheet, and SolidWorks). The flow

  20. Learning at the workplace and sustainable employability: a multi-source model moderated by age

    NARCIS (Netherlands)

    van der Heijden, Beatrice; Gorgievski, Marjan J.; de Lange, Annet H.

    2015-01-01

    This study, among 330 pairs of employees and their supervisors, tested whether self- versus supervisor ratings of five employability dimensions (occupational expertise, corporate sense, personal flexibility, anticipation and optimization, and balance) are associated with different learning

  1. Illstrative probabilistic biosphere model for Yucca Mountain individual risk calculations

    International Nuclear Information System (INIS)

    Wilems, R.E.

    1994-01-01

    The proposed EPA Standards for the disposal of spent fuel, high-level and transuranic radioactive waste prescribe future biosphere--one in which no sustained human activity occurs inside the controlled zone, yet sustained use of groundwater occurs just outside the controlled zone boundary. Performance assessments have generally assumed a person at this location extracts all his water needs directly from the projected contaminated plume for all of his life. Dose to this maximally-exposed individual is too conservative a measure of performance for a nuclear waste repository and does not reflect the isolation characteristics of a site. A better measure is individual risk in which uncertainties in biosphere characteristics for the longer periods of performance, for a site like Yucca Mountain only those characteristics associated with well water scenarios need be prescribed. Such a prescription of the biosphere is appropriate because the goal of the regulations is to provide indicators of future performance so the regulators can make a responsible decision regarding reasonable assurance of public health and safety

  2. Student employment

    DEFF Research Database (Denmark)

    Jacob, Marita; Gerth, Maria; Weiss, Felix

    2018-01-01

    In this article, we examine social origin differences in employment patterns across different stages of higher education and compare these differences between vocational and academic fields of study. Using data from a large-scale German student survey, we study the development of inequality, acco...... decrease as students progress through higher education. While we find evidence for this hypothesis, we also show in multivariate models that the reduction of inequality in the student labour market is explained by prior differences between social origin groups.......In this article, we examine social origin differences in employment patterns across different stages of higher education and compare these differences between vocational and academic fields of study. Using data from a large-scale German student survey, we study the development of inequality...

  3. Individual discriminative face recognition models based on subsets of features

    DEFF Research Database (Denmark)

    Clemmensen, Line Katrine Harder; Gomez, David Delgado; Ersbøll, Bjarne Kjær

    2007-01-01

    of the face recognition problem. The elastic net model is able to select a subset of features with low computational effort compared to other state-of-the-art feature selection methods. Furthermore, the fact that the number of features usually is larger than the number of images in the data base makes feature......The accuracy of data classification methods depends considerably on the data representation and on the selected features. In this work, the elastic net model selection is used to identify meaningful and important features in face recognition. Modelling the characteristics which distinguish one...... person from another using only subsets of features will both decrease the computational cost and increase the generalization capacity of the face recognition algorithm. Moreover, identifying which are the features that better discriminate between persons will also provide a deeper understanding...

  4. Developing population models with data from marked individuals

    Science.gov (United States)

    Hae Yeong Ryu,; Kevin T. Shoemaker,; Eva Kneip,; Anna Pidgeon,; Patricia Heglund,; Brooke Bateman,; Thogmartin, Wayne E.; Reşit Akçakaya,

    2016-01-01

    Population viability analysis (PVA) is a powerful tool for biodiversity assessments, but its use has been limited because of the requirements for fully specified population models such as demographic structure, density-dependence, environmental stochasticity, and specification of uncertainties. Developing a fully specified population model from commonly available data sources – notably, mark–recapture studies – remains complicated due to lack of practical methods for estimating fecundity, true survival (as opposed to apparent survival), natural temporal variability in both survival and fecundity, density-dependence in the demographic parameters, and uncertainty in model parameters. We present a general method that estimates all the key parameters required to specify a stochastic, matrix-based population model, constructed using a long-term mark–recapture dataset. Unlike standard mark–recapture analyses, our approach provides estimates of true survival rates and fecundities, their respective natural temporal variabilities, and density-dependence functions, making it possible to construct a population model for long-term projection of population dynamics. Furthermore, our method includes a formal quantification of parameter uncertainty for global (multivariate) sensitivity analysis. We apply this approach to 9 bird species and demonstrate the feasibility of using data from the Monitoring Avian Productivity and Survivorship (MAPS) program. Bias-correction factors for raw estimates of survival and fecundity derived from mark–recapture data (apparent survival and juvenile:adult ratio, respectively) were non-negligible, and corrected parameters were generally more biologically reasonable than their uncorrected counterparts. Our method allows the development of fully specified stochastic population models using a single, widely available data source, substantially reducing the barriers that have until now limited the widespread application of PVA. This method

  5. Conceptual Models of the Individual Public Service Provider

    DEFF Research Database (Denmark)

    Andersen, Lotte Bøgh; Bhatti, Yosef; Petersen, Ole Helby

    Individual public service providers’ motivation can be conceptualized as either extrinsic, autonomous or prosocial, and the question is how we can best theoretically understand this complexity without losing too much coherence and parsimony. Drawing on Allison’s approach (1969), three perspectives...... are used to gain insight on the motivation of public service providers; namely principal-agent theory, self-determination theory and public service motivation theory. We situate the theoretical discussions in the context of public service providers being transferred to private organizations...... as a consequence of outsourcing by the public sector. Although this empirical setting is interesting in itself, here it serves primarily as grist for a wider discussion on strategies for applying multiple theoretical approaches and crafting a theoretical synthesis. The key contribution of the paper is thus...

  6. An individual-level selection model for the apparent altruism ...

    Indian Academy of Sciences (India)

    Amotz Zahavi

    2018-02-16

    Feb 16, 2018 ... remain solitary when the rest have completed aggregation. Their response to starvation (apparently) is not to become part of an aggregate, but instead to take a chance on a fresh source of food appearing quickly. Modelling shows that given the right environmental conditions, this can work. (Tarnita et al.

  7. A finite-element reciprocity solution for EEG forward modeling with realistic individual head models.

    Science.gov (United States)

    Ziegler, Erik; Chellappa, Sarah L; Gaggioni, Giulia; Ly, Julien Q M; Vandewalle, Gilles; André, Elodie; Geuzaine, Christophe; Phillips, Christophe

    2014-12-01

    We present a finite element modeling (FEM) implementation for solving the forward problem in electroencephalography (EEG). The solution is based on Helmholtz's principle of reciprocity which allows for dramatically reduced computational time when constructing the leadfield matrix. The approach was validated using a 4-shell spherical model and shown to perform comparably with two current state-of-the-art alternatives (OpenMEEG for boundary element modeling and SimBio for finite element modeling). We applied the method to real human brain MRI data and created a model with five tissue types: white matter, gray matter, cerebrospinal fluid, skull, and scalp. By calculating conductivity tensors from diffusion-weighted MR images, we also demonstrate one of the main benefits of FEM: the ability to include anisotropic conductivities within the head model. Root-mean square deviation between the standard leadfield and the leadfield including white-matter anisotropy showed that ignoring the directional conductivity of white matter fiber tracts leads to orientation-specific errors in the forward model. Realistic head models are necessary for precise source localization in individuals. Our approach is fast, accurate, open-source and freely available online. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Modeling auditory perception of individual hearing-impaired listeners

    DEFF Research Database (Denmark)

    Jepsen, Morten Løve; Dau, Torsten

    showed that, in most cases, the reduced or absent cochlear compression, associated with outer hair-cell loss, quantitatively accounts for broadened auditory filters, while a combination of reduced compression and reduced inner hair-cell function accounts for decreased sensitivity and slower recovery from...... selectivity. Three groups of listeners were considered: (a) normal hearing listeners; (b) listeners with a mild-to-moderate sensorineural hearing loss; and (c) listeners with a severe sensorineural hearing loss. A fixed set of model parameters were derived for each hearing-impaired listener. The simulations...

  9. Magnetic field modeling with a set of individual localized coils.

    Science.gov (United States)

    Juchem, Christoph; Nixon, Terence W; McIntyre, Scott; Rothman, Douglas L; de Graaf, Robin A

    2010-06-01

    A set of generic, circular individual coils is shown to be capable of generating highly complex magnetic field distributions in a flexible fashion. Arbitrarily oriented linear field gradients can be generated in three-dimensional as well as sliced volumes at amplitudes that allow imaging applications. The multi-coil approach permits the simultaneous generation of linear MRI encoding fields and complex shim fields by the same setup, thereby reducing system complexity. The choice of the sensitive volume over which the magnetic fields are optimized remains temporally and spatially variable at all times. The restriction of the field synthesis to experimentally relevant, smaller volumes such as single slices directly translates into improved efficiency, i.e. higher magnetic field amplitudes and/or reduced coil currents. For applications like arterial spin labeling, signal spoiling and diffusion weighting, perfect linearity of the gradient fields is not required and reduced demands on accuracy can also be readily translated into improved efficiency. The first experimental realization was achieved for mouse head MRI with 24 coils that were mounted on the surface of a cylindrical former. Oblique linear field gradients of 20 kHz/cm (47 mT/m) were generated with a maximum current of 1.4A which allowed radial imaging of a mouse head. The potential of the new approach for generating arbitrary magnetic field shapes is demonstrated by synthesizing the more complex, higher order spherical harmonic magnetic field distributions X2-Y2, Z2 and Z2X. The new multi-coil approach provides the framework for the integration of conventional imaging and shim coils into a single multi-coil system in which shape, strength, accuracy and spatial coverage of the magnetic field can be specifically optimized for the application at hand. (c) 2010 Elsevier Inc. All rights reserved.

  10. CLRP: Individual evaluation of model performance for scenario S

    International Nuclear Information System (INIS)

    Krajewski, P.

    1996-01-01

    The model CLRP was created in 1989 as a part of research project ''Long-Lived Post-Chernobyl Radioactivity and Radiation Protection Criteria for Risk Reduction'' performed in cooperation with US Environmental Protection Agency. The aim of this project was to examine the fate of long-lived radionuclides in the terrestrial ecosystem. Concentrations of Cs-137 and Cs-134 in the particular components of terrestrial ecosystem e.g. soil, vegetation, animal tissues and animal products are calculated as a function of time following deposition from the atmosphere. Based on this data the whole body contents of radionuclide as a function of time is calculated and dose to a specific organ for the radionuclide may be estimated as an integral of the resultant dose rate over a sufficient period. In addition, the model allows estimation of inhalation dose from time integrated air concentration and external dose from total deposition using simple conversion factors. The program is designed to allow the simulation of many different radiological situations (chronic or acute releases) and dose affecting countermeasures. Figs, tabs

  11. Model-Based Individualized Treatment of Chemotherapeutics: Bayesian Population Modeling and Dose Optimization.

    Directory of Open Access Journals (Sweden)

    Devaraj Jayachandran

    Full Text Available 6-Mercaptopurine (6-MP is one of the key drugs in the treatment of many pediatric cancers, auto immune diseases and inflammatory bowel disease. 6-MP is a prodrug, converted to an active metabolite 6-thioguanine nucleotide (6-TGN through enzymatic reaction involving thiopurine methyltransferase (TPMT. Pharmacogenomic variation observed in the TPMT enzyme produces a significant variation in drug response among the patient population. Despite 6-MP's widespread use and observed variation in treatment response, efforts at quantitative optimization of dose regimens for individual patients are limited. In addition, research efforts devoted on pharmacogenomics to predict clinical responses are proving far from ideal. In this work, we present a Bayesian population modeling approach to develop a pharmacological model for 6-MP metabolism in humans. In the face of scarcity of data in clinical settings, a global sensitivity analysis based model reduction approach is used to minimize the parameter space. For accurate estimation of sensitive parameters, robust optimal experimental design based on D-optimality criteria was exploited. With the patient-specific model, a model predictive control algorithm is used to optimize the dose scheduling with the objective of maintaining the 6-TGN concentration within its therapeutic window. More importantly, for the first time, we show how the incorporation of information from different levels of biological chain-of response (i.e. gene expression-enzyme phenotype-drug phenotype plays a critical role in determining the uncertainty in predicting therapeutic target. The model and the control approach can be utilized in the clinical setting to individualize 6-MP dosing based on the patient's ability to metabolize the drug instead of the traditional standard-dose-for-all approach.

  12. Effectiveness of Facebook Based Learning to Enhance Creativity among Islamic Studies Students by Employing Isman Instructional Design Model

    Science.gov (United States)

    Alias, Norlidah; Siraj, Saedah; Daud, Mohd Khairul Azman Md; Hussin, Zaharah

    2013-01-01

    The study examines the effectiveness of Facebook based learning to enhance creativity among Islamic Studies students in the secondary educational setting in Malaysia. It describes the design process by employing the Isman Instructional Design Model. A quantitative study was carried out using experimental method and background survey. The…

  13. Do Labour Market Programmes Necessarily Crowd out Regular Employment? A Matching Model Analysis

    NARCIS (Netherlands)

    Miller, J.G.

    1996-01-01

    It is often claimed that the usage of labour market programmes will necessarily crowd out regular employment (see, for example, Holmlund & Lindén (1993)). As a result, it could be argued that, despite their probable negative impact on unemployment, the overall benefits of using labour market

  14. Predictive models to determine imagery strategies employed by children to judge hand laterality

    NARCIS (Netherlands)

    Spruijt, S.; Jongsma, M.L.A.; Kamp, J. van der; Steenbergen, B.

    2015-01-01

    A commonly used paradigm to study motor imagery is the hand laterality judgment task. The present study aimed to determine which strategies young children employ to successfully perform this task. Children of 5 to 8 years old (N = 92) judged laterality of back and palm view hand pictures in

  15. Predictive models to determine imagery strategies employed by children to judge hand laterality.

    NARCIS (Netherlands)

    Spruijt, S.; Jongsma, M.L.; Kamp, J. van der; Steenbergen, B.

    2015-01-01

    A commonly used paradigm to study motor imagery is the hand laterality judgment task. The present study aimed to determine which strategies young children employ to successfully perform this task. Children of 5 to 8 years old (N = 92) judged laterality of back and palm view hand pictures in

  16. Integrating ecological insight derived from individual-based simulations and physiologically structured population models

    NARCIS (Netherlands)

    Nisbet, R.M.; Martin, B.T.; de Roos, A.M.

    2016-01-01

    Two contrasting approaches are widely used to derive population dynamics as an emergent property deriving from the physiology and behavior of individual organisms. "Individual-based models" (IBMs) are computer simulations where the "state" (e.g., age, size) of each individual in a population is fol-

  17. Assessing the Contribution of Unstable Employment to Mortality in Posttransition Russia: Prospective Individual-Level Analyses From the Russian Longitudinal Monitoring Survey

    Science.gov (United States)

    Bobak, Martin

    2009-01-01

    Objectives. We used the Russia Longitudinal Monitoring Survey (RLMS) to investigate associations between employment, socioeconomic position, and mortality. Methods. Data were from working-age respondents in 8 rounds (1994–2003) of the RLMS. We measured associations between education, occupation, unemployment, and insecure employment and mortality with Cox proportional hazards analyses. Results. Of 4465 men and 4158 women who were currently employed, 251 men and 34 women died. A third of employed respondents experienced wage arrears, and 10% experienced compulsory leave and payment in consumer goods. Insecure employment, more common among the less-educated and manual workers, fluctuated with macroeconomic measures. Mortality was significantly associated with payment in consumer goods among men (hazard ratio [HR] = 1.46; 95% confidence interval [CI] = 1.03, 2.07), compulsory unpaid leave among women (HR = 3.79; 95% CI = 1.82, 7.88), and male unemployment (HR = 1.88; 95% CI = 1.38, 2.55). Associations with death within 1 year of entry were generally somewhat stronger than the association with mortality over the whole study period. Conclusions. Unemployment and job insecurity predicted mortality, suggesting that they contributed to Russia's high mortality during the transition from communism. PMID:19696378

  18. Traveling waves for a model of individual clustering with logistic growth rate

    Science.gov (United States)

    Ibrahim, H.; Nasreddine, E.

    2017-08-01

    We consider a traveling wave problem for a one-dimensional model of individual clustering or aggregation. This model, originally formulated by Grindrod [J. Math. Biol. 26(6), 651-660 (1988)], describes the mechanism of individual dispersion when individuals are able to utilize information about their local environment. Specifically, it assumes that each individual disperses randomly with probability δ and disperses deterministically so as to improve his reproductive rate with probability 1 -δ . In this paper, we prove the existence of a traveling wave solution when the probability of random dispersion exceeds a critical value δ* uniquely determined by the biased individual velocity.

  19. Computational modeling and statistical analyses on individual contact rate and exposure to disease in complex and confined transportation hubs

    Science.gov (United States)

    Wang, W. L.; Tsui, K. L.; Lo, S. M.; Liu, S. B.

    2018-01-01

    Crowded transportation hubs such as metro stations are thought as ideal places for the development and spread of epidemics. However, for the special features of complex spatial layout, confined environment with a large number of highly mobile individuals, it is difficult to quantify human contacts in such environments, wherein disease spreading dynamics were less explored in the previous studies. Due to the heterogeneity and dynamic nature of human interactions, increasing studies proved the importance of contact distance and length of contact in transmission probabilities. In this study, we show how detailed information on contact and exposure patterns can be obtained by statistical analyses on microscopic crowd simulation data. To be specific, a pedestrian simulation model-CityFlow was employed to reproduce individuals' movements in a metro station based on site survey data, values and distributions of individual contact rate and exposure in different simulation cases were obtained and analyzed. It is interesting that Weibull distribution fitted the histogram values of individual-based exposure in each case very well. Moreover, we found both individual contact rate and exposure had linear relationship with the average crowd densities of the environments. The results obtained in this paper can provide reference to epidemic study in complex and confined transportation hubs and refine the existing disease spreading models.

  20. Coupling of an individual-based model of anchovy with lower trophic level and hydrodynamic models

    Science.gov (United States)

    Wang, Yuheng; Wei, Hao; Kishi, Michio J.

    2013-03-01

    Anchovy ( Engraulis japonicus), a small pelagic fish and food of other economic fishes, is a key species in the Yellow Sea ecosystem. Understanding the mechanisms of its recruitment and biomass variation is important for the prediction and management of fishery resources. Coupled with a hydrodynamic model (POM) and a lower trophic level ecosystem model (NEMURO), an individual-based model of anchovy is developed to study the influence of physical environment on anchovy's biomass variation. Seasonal variations of circulation, water temperature and mix-layer depth from POM are used as external forcing for NEMURO and the anchovy model. Biomasses of large zooplankton and predatory zooplankton which anchovy feeds on are output from NEMURO and are controlled by the consumption of anchovy on them. Survival fitness theory related to temperature and food is used to determine the swimming action of anchovy in the model. The simulation results agree well with observations and elucidate the influence of temperature in over-wintering migration and food in feeding migration.

  1. Modeling Systematicity and Individuality in Nonlinear Second Language Development: The Case of English Grammatical Morphemes

    Science.gov (United States)

    Murakami, Akira

    2016-01-01

    This article introduces two sophisticated statistical modeling techniques that allow researchers to analyze systematicity, individual variation, and nonlinearity in second language (L2) development. Generalized linear mixed-effects models can be used to quantify individual variation and examine systematic effects simultaneously, and generalized…

  2. The Rape Prevention and Education (RPE) Theory Model of Community Change: Connecting Individual and Social Change

    Science.gov (United States)

    Cox, Pamela J.; Lang, Karen S.; Townsend, Stephanie M.; Campbell, Rebecca

    2010-01-01

    Social work practice has long focused on the connections between an individual and the social environment that affect the individual's social functioning. The Rape Prevention and Education (RPE) Program's theory model, Creating Safer Communities: The Rape Prevention and Education Model of Community Change, provides family social workers with a…

  3. Maximum likelihood estimators for extended growth curve model with orthogonal between-individual design matrices

    NARCIS (Netherlands)

    Klein, Daniel; Zezula, Ivan

    The extended growth curve model is discussed in this paper. There are two versions of the model studied in the literature, which differ in the way how the column spaces of the design matrices are nested. The nesting is applied either to the between-individual or to the within-individual design

  4. Modeling the Individual Within the Group: an Interdisciplinary Approach to Collaborative Knowledge Construction

    OpenAIRE

    Lund, Kristine

    2016-01-01

    Constructing knowledge with others is fundamental for all human activity, and many disciplines have sought to understand how the individual, other people, and the context, all influence collaborative knowledge construction, be it individual or group knowledge. The goal of this Habilitation à Diriger des Recherches is to present an analytical model of the relations of the individual to the group in situations of collaborative knowledge construction. The model is inspired by the work of Levinso...

  5. A Note on the Use of Mixture Models for Individual Prediction.

    Science.gov (United States)

    Cole, Veronica T; Bauer, Daniel J

    Mixture models capture heterogeneity in data by decomposing the population into latent subgroups, each of which is governed by its own subgroup-specific set of parameters. Despite the flexibility and widespread use of these models, most applications have focused solely on making inferences for whole or sub-populations, rather than individual cases. The current article presents a general framework for computing marginal and conditional predicted values for individuals using mixture model results. These predicted values can be used to characterize covariate effects, examine the fit of the model for specific individuals, or forecast future observations from previous ones. Two empirical examples are provided to demonstrate the usefulness of individual predicted values in applications of mixture models. The first example examines the relative timing of initiation of substance use using a multiple event process survival mixture model whereas the second example evaluates changes in depressive symptoms over adolescence using a growth mixture model.

  6. Spatial organization of mesenchymal stem cells in vitro--results from a new individual cell-based model with podia.

    Directory of Open Access Journals (Sweden)

    Martin Hoffmann

    Full Text Available Therapeutic application of mesenchymal stem cells (MSC requires their extensive in vitro expansion. MSC in culture typically grow to confluence within a few weeks. They show spindle-shaped fibroblastoid morphology and align to each other in characteristic spatial patterns at high cell density. We present an individual cell-based model (IBM that is able to quantitatively describe the spatio-temporal organization of MSC in culture. Our model substantially improves on previous models by explicitly representing cell podia and their dynamics. It employs podia-generated forces for cell movement and adjusts cell behavior in response to cell density. At the same time, it is simple enough to simulate thousands of cells with reasonable computational effort. Experimental sheep MSC cultures were monitored under standard conditions. Automated image analysis was used to determine the location and orientation of individual cells. Our simulations quantitatively reproduced the observed growth dynamics and cell-cell alignment assuming cell density-dependent proliferation, migration, and morphology. In addition to cell growth on plain substrates our model captured cell alignment on micro-structured surfaces. We propose a specific surface micro-structure that according to our simulations can substantially enlarge cell culture harvest. The 'tool box' of cell migratory behavior newly introduced in this study significantly enhances the bandwidth of IBM. Our approach is capable of accommodating individual cell behavior and collective cell dynamics of a variety of cell types and tissues in computational systems biology.

  7. A comparative analysis of reactor lower head debris cooling models employed in the existing severe accident analysis codes

    International Nuclear Information System (INIS)

    Ahn, K.I.; Kim, D.H.; Kim, S.B.; Kim, H.D.

    1998-08-01

    MELCOR and MAAP4 are the representative severe accident analysis codes which have been developed for the integral analysis of the phenomenological reactor lower head corium cooling behavior. Main objectives of the present study is to identify merits and disadvantages of each relevant model through the comparative analysis of the lower plenum corium cooling models employed in these two codes. The final results will be utilized for the development of LILAC phenomenological models and for the continuous improvement of the existing MELCOR reactor lower head models, which are currently being performed at the KAERI. For these purposes, first, nine reference models are selected featuring the lower head corium behavior based on the existing experimental evidences and related models. Then main features of the selected models have been critically analyzed, and finally merits and disadvantages of each corresponding model have been summarized in the view point of realistic corium behavior and reasonable modeling. Being on these evidences, summarized and presented the potential improvements for developing more advanced models. The present study has been focused on the qualitative comparison of each model and so more detailed quantitative analysis is strongly required to obtain the final conclusions for their merits and disadvantages. In addition, in order to compensate the limitations of the current model, required further studies relating closely the detailed mechanistic models with the molten material movement and heat transfer based on phase-change in the porous medium, to the existing simple models. (author). 36 refs

  8. Modeling regional population-employment dynamics across different sectors of the economy

    NARCIS (Netherlands)

    Graaff, T. de; Oort, F.G. van; Florax, R.

    An important subset of the literature on agglomeration externalities hypothesizes that intrasectoral and intersectoral relations are endogenously determined in models of local and regional economic growth. Remarkably, structural adjustment models describing the spatio-temporal dynamics of

  9. Coping among individuals with multiple sclerosis: Evaluating a goodness-of-fit model.

    Science.gov (United States)

    Roubinov, Danielle S; Turner, Aaron P; Williams, Rhonda M

    2015-05-01

    Multiple sclerosis (MS) is a chronic illness involving both controllable and uncontrollable stressors. The goodness-of-fit hypothesis posits that managing stressors effectively requires the use of different coping approaches in the face of controllable and uncontrollable stressors. To test the applicability of the goodness-of-fit model in a sample of adults with MS, we evaluated the ratio of 2 types of coping (an active problem-solving approach and an emotion-based meaning-focused approach) as a moderator of the relations between stress uncontrollability and mental health outcomes. Participants were veterans with MS (N = 90) receiving medical services through the Veterans Health Administration who completed telephone-based interviews. Regression analyses tested the interaction of stress uncontrollability and the problem- and meaning-focused coping ratio on anxious and depressive symptoms. Significant interactions were probed at 1 SD above the mean of coping (use of predominantly problem-focused coping) and 1 SD below the mean of coping (use of predominantly meaning-focused coping). Findings largely supported the goodness-of-fit hypothesis. Anxiety and depressive symptoms were elevated when participants used more problem-focused strategies relative to meaning-focused strategies in the face of perceived uncontrollable stress. Conversely, symptoms of anxiety and depression were lower when uncontrollable stress was met with predominantly meaning-focused coping; however, the relations did not reach statistical significance. The impact of uncontrollable stressors on mental health outcomes for individuals with MS may vary depending on the degree to which problem-focused versus meaning-focused coping strategies are employed, lending support to the goodness-of-fit model. (c) 2015 APA, all rights reserved).

  10. Assessment of training effects on employability within the institutional Spanish training model

    Directory of Open Access Journals (Sweden)

    Ramírez-del-Río, Antonio

    2011-12-01

    Full Text Available The association between quantity of training and employability was analysed through a non experimental research with two non equivalent groups. The operationalization of training quantity is considered to provide an indicator of training effort. Thus, training effort (number of courses was analysed as the independent variable and employability as dependent variable (occupation indicators, activity enhancement and job performance. The results show that training is related to activity enhancement, specially when workers belong to a small/medium enterprise (SME and/or to technical or qualified positions. A positive association between training and performance also appeared in the case of SMEs. Se analiza la asociación entre cantidad de formación y empleabilidad mediante una investigación no experimental con dos grupos no equivalentes. Se considera que la operativización de la cantidad de formación proporciona un indicador próximo al esfuerzo formativo realizado. Así, se estudió la variable independiente esfuerzo formativo (número de cursos y la dependiente, empleabilidad (indicadores de ocupación, enriquecimiento de actividad y desempeño. Los resultados muestran que la formación está asociada al enriquecimiento de la actividad, sobre todo si los trabajadores pertenecen a una PYME y/o a puestos técnicos o cualificados. También hay una asociación positiva entre formación y desempeño en PYMES.

  11. Bayesian Model Averaging Employing Fixed and Flexible Priors: The BMS Package for R

    Directory of Open Access Journals (Sweden)

    Stefan Zeugner

    2015-11-01

    Full Text Available This article describes the BMS (Bayesian model sampling package for R that implements Bayesian model averaging for linear regression models. The package excels in allowing for a variety of prior structures, among them the "binomial-beta" prior on the model space and the so-called "hyper-g" specifications for Zellner's g prior. Furthermore, the BMS package allows the user to specify her own model priors and offers a possibility of subjective inference by setting "prior inclusion probabilities" according to the researcher's beliefs. Furthermore, graphical analysis of results is provided by numerous built-in plot functions of posterior densities, predictive densities and graphical illustrations to compare results under different prior settings. Finally, the package provides full enumeration of the model space for small scale problems as well as two efficient MCMC (Markov chain Monte Carlo samplers that sort through the model space when the number of potential covariates is large.

  12. A structural econometric model of family valuation and choice of employer-sponsored health insurance in the United States.

    Science.gov (United States)

    Vanness, David J

    2003-09-01

    This paper estimates a fully structural unitary household model of employment and health insurance decisions for dual wage-earner families with children in the United States, using data from the 1987 National Medical Expenditure Survey. Families choose hours of work and the breakdown of compensation between cash wages and health insurance benefits for each wage earner in order to maximize expected utility under uncertain need for medical care. Heterogeneous demand for the employer-sponsored health insurance is thus generated directly from variations in health status and earning potential. The paper concludes by discussing the benefits of using structural models for simulating welfare effects of insurance reform relative to the costly assumptions that must be imposed for identification. Copyright 2003 John Wiley & Sons, Ltd.

  13. Identify Strategies to Expand Employment in Rural Areas Using the SWOT Model (Case Study: Badr District, Ravansar Township

    Directory of Open Access Journals (Sweden)

    Davood Jamini

    2015-01-01

    Full Text Available The aim of the present study, Is the nature and procedure respectively of the applied research and descriptive, Provide solutions to expand employment in the village of Badr District. The main research instrument was researcher made questionnaire and to achieve this goal, researchers have used opinions 23 expert relating to rural affairs Ravansar Township. Is used to analyze the data from the Excel software and the SWOT Model. The results showed there are in the study area 23 strength of (with a final score of 1.800 and 25 opportunities (with a final score of 1.933 for employment development. While face village of Bedar District with 35 point of weakness (with a final score of 11.946 and 16 threat (with a final score of 1.993 to develop employment. In total the results showed, According to the Preponderance weaknesses and threats on the strengths and opportunities in the study area, there is Defensive strategy (WT, priority employment development strategies in village of Badr District. Therefore, is necessary for provide solutions development employment In rural areas in the study area, Weaken the Internal weaknesses (such as lack of initial capital available to villagers With The final weight 0.136, There Fixer and intermediaries With The final weight 0.105 and External threats (such as limited capital in the hands of villagers With final weight 0.272 and Rising production costs with the final weight 0.262, Which have the greatest weight. Finally, According to research findings, was developed to promote employment in the village of Badr district, Practical and effective solutions, which have been the main focus on the Limiting the identified weaknesses and threats.

  14. mMWeb--an online platform for employing multiple ecological niche modeling algorithms.

    Science.gov (United States)

    Qiao, Huijie; Lin, Congtian; Ji, Liqiang; Jiang, Zhigang

    2012-01-01

    Predicting the ecological niche and potential habitat distribution of a given organism is one of the central domains of ecological and biogeographical research. A wide variety of modeling techniques have been developed for this purpose. In order to implement these models, the users must prepare a specific runtime environment for each model, learn how to use multiple model platforms, and prepare data in a different format each time. Additionally, often model results are difficult to interpret, and a standardized method for comparing model results across platforms does not exist. We developed a free and open source online platform, the multi-models web-based (mMWeb) platform, to address each of these problems, providing a novel environment in which the user can implement and compare multiple ecological niche model (ENM) algorithms. mMWeb combines 18 existing ENMs and their corresponding algorithms and provides a uniform procedure for modeling the potential habitat niche of a species via a common web browser. mMWeb uses Java Native Interface (JNI), Java R Interface to combine the different ENMs and executes multiple tasks in parallel on a super computer. The cross-platform, user-friendly interface of mMWeb simplifies the process of building ENMs, providing an accessible and efficient environment from which to explore and compare different model algorithms.

  15. mMWeb--an online platform for employing multiple ecological niche modeling algorithms.

    Directory of Open Access Journals (Sweden)

    Huijie Qiao

    Full Text Available BACKGROUND: Predicting the ecological niche and potential habitat distribution of a given organism is one of the central domains of ecological and biogeographical research. A wide variety of modeling techniques have been developed for this purpose. In order to implement these models, the users must prepare a specific runtime environment for each model, learn how to use multiple model platforms, and prepare data in a different format each time. Additionally, often model results are difficult to interpret, and a standardized method for comparing model results across platforms does not exist. We developed a free and open source online platform, the multi-models web-based (mMWeb platform, to address each of these problems, providing a novel environment in which the user can implement and compare multiple ecological niche model (ENM algorithms. METHODOLOGY: mMWeb combines 18 existing ENMs and their corresponding algorithms and provides a uniform procedure for modeling the potential habitat niche of a species via a common web browser. mMWeb uses Java Native Interface (JNI, Java R Interface to combine the different ENMs and executes multiple tasks in parallel on a super computer. The cross-platform, user-friendly interface of mMWeb simplifies the process of building ENMs, providing an accessible and efficient environment from which to explore and compare different model algorithms.

  16. MULTIREGION: a simulation-forecasting model of BEA economic area population and employment. [Bureau of Economic Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, R.J.; Westley, G.W.; Herzog, H.W. Jr.; Kerley, C.R.; Bjornstad, D.J.; Vogt, D.P.; Bray, L.G.; Grady, S.T.; Nakosteen, R.A.

    1977-10-01

    This report documents the development of MULTIREGION, a computer model of regional and interregional socio-economic development. The MULTIREGION model interprets the economy of each BEA economic area as a labor market, measures all activity in terms of people as members of the population (labor supply) or as employees (labor demand), and simultaneously simulates or forecasts the demands and supplies of labor in all BEA economic areas at five-year intervals. In general the outputs of MULTIREGION are intended to resemble those of the Water Resource Council's OBERS projections and to be put to similar planning and analysis purposes. This report has been written at two levels to serve the needs of multiple audiences. The body of the report serves as a fairly nontechnical overview of the entire MULTIREGION project; a series of technical appendixes provide detailed descriptions of the background empirical studies of births, deaths, migration, labor force participation, natural resource employment, manufacturing employment location, and local service employment used to construct the model.

  17. Analysis of individual cell trajectories in lattice-gas cellular automaton models for migrating cell populations.

    Science.gov (United States)

    Mente, Carsten; Voss-Böhme, Anja; Deutsch, Andreas

    2015-04-01

    Collective dynamics of migrating cell populations drive key processes in tissue formation and maintenance under normal and diseased conditions. Collective cell behavior at the tissue level is typically characterized by considering cell density patterns such as clusters and moving cell fronts. However, there are also important observables of collective dynamics related to individual cell behavior. In particular, individual cell trajectories are footprints of emergent behavior in populations of migrating cells. Lattice-gas cellular automata (LGCA) have proven successful to model and analyze collective behavior arising from interactions of migrating cells. There are well-established methods to analyze cell density patterns in LGCA models. Although LGCA dynamics are defined by cell-based rules, individual cells are not distinguished. Therefore, individual cell trajectories cannot be analyzed in LGCA so far. Here, we extend the classical LGCA framework to allow labeling and tracking of individual cells. We consider cell number conserving LGCA models of migrating cell populations where cell interactions are regulated by local cell density and derive stochastic differential equations approximating individual cell trajectories in LGCA. This result allows the prediction of complex individual cell trajectories emerging in LGCA models and is a basis for model-experiment comparisons at the individual cell level.

  18. The Effect of Off-Farm Employment on Forestland Transfers in China: A Simultaneous-Equation Tobit Model Estimation

    Directory of Open Access Journals (Sweden)

    Han Zhang

    2017-09-01

    Full Text Available China’s new round tenure reform has devolved collective forests to individuals on an egalitarian basis. To balance the equity–efficiency dilemma, forestland transfers are highly advocated by policymakers. However, the forestland rental market is still inactive after the reform. To examine the role of off-farm employment in forestland transfers, a simultaneous Tobit system of equations was employed to account for the endogeneity, interdependency, and censoring issues. Accordingly, the Nelson–Olson two-stage procedure, embedded with a multivariate Tobit estimator, was applied to a nationally representative dataset. The estimation results showed that off-farm employment plays a significantly negative role in forestland rent-in, at the 5% risk level. However, off-farm activities had no significant effect on forestland rent-out. Considering China’s specific situation, a reasonable explanation is that households hold forestland as a crucial means of social security against the risk of unemployment. In both rent-in and rent-out equations, high transaction costs are one of the main obstacles impeding forestland transfer. A remarkable finding was that forestland transactions occurred with a statistically significant factor equalization effect, which would be helpful to adjust the mismatched labor–land ratio and improve the land-use efficiency.

  19. The viability of neural network for modeling the impact of individual job satisfiers on work commitment in Indian manufacturing unit

    Directory of Open Access Journals (Sweden)

    Therasa Chandrasekar

    2015-10-01

    Full Text Available This paper provides an exposition about application of neural networks in the context of research to find out the contribution of individual job satisfiers towards work commitment. The purpose of the current study is to build a predictive model to estimate the normalized importance of individual job satisfiers towards work commitment of employees working in TVS Group, an Indian automobile company. The study is based on the tool developed by Spector (1985 and Sue Hayday (2003.The input variable of the study consists of nine independent individual job satisfiers which includes Pay, Promotion, Supervision, Benefits, Rewards, Operating procedures, Co-workers, Work-itself and Communication of Spector (1985 and dependent variable as work commitment of Sue Hayday (2003.The primary data has been collected using a closed-ended questionnaire based on simple random sampling approach. This study employed the multilayer Perceptron neural network model to envisage the level of job satisfiers towards work commitment. The result from the multilayer Perceptron neural network model displayed with four hidden layer with correct classification rate of 70% and 30% for training and testing data set. The normalized importance shows high value for coworkers, superior satisfaction and communication and which acts as most significant attributes of job satisfiers that predicts the overall work commitment of employees.

  20. The Impact of Supported Employment and Working on Clinical and Social Functioning : Results of an International Study of Individual Placement and Support

    NARCIS (Netherlands)

    Burns, Tom; Catty, Jocelyn; White, Sarah; Becker, Thomas; Koletsi, Marsha; Fioritti, Angelo; Roessler, Wulf; Tomov, Toma; van Busschbach, Jooske; Wiersma, Durk; Lauber, Christoph; Rossler, W.

    Background: Concerns are frequently expressed that working might worsen the mental health of people with severe mental illness (SMI). Several studies of Individual Placement and Support (IPS), however, have found associations between working and better nonvocational outcomes. IPS has been found to

  1. Effects of uncertainty in model predictions of individual tree volume on large area volume estimates

    Science.gov (United States)

    Ronald E. McRoberts; James A. Westfall

    2014-01-01

    Forest inventory estimates of tree volume for large areas are typically calculated by adding model predictions of volumes for individual trees. However, the uncertainty in the model predictions is generally ignored with the result that the precision of the large area volume estimates is overestimated. The primary study objective was to estimate the effects of model...

  2. Career Planning: Towards a More Inclusive Model for Women and Diverse Individuals

    Science.gov (United States)

    Banks, Claretha H.

    2006-01-01

    Since the 1953 introduction of Super's model of career development, many publications regarding career development and career planning have been developed. However, career planning models for women and diverse individuals are not prevalent. This paper contains a literature review of various well-known models that have few specific applications for…

  3. Predicting Longitudinal Change in Language Production and Comprehension in Individuals with Down Syndrome: Hierarchical Linear Modeling.

    Science.gov (United States)

    Chapman, Robin S.; Hesketh, Linda J.; Kistler, Doris J.

    2002-01-01

    Longitudinal change in syntax comprehension and production skill, measured over six years, was modeled in 31 individuals (ages 5-20) with Down syndrome. The best fitting Hierarchical Linear Modeling model of comprehension uses age and visual and auditory short-term memory as predictors of initial status, and age for growth trajectory. (Contains…

  4. A Linear Variable-[theta] Model for Measuring Individual Differences in Response Precision

    Science.gov (United States)

    Ferrando, Pere J.

    2011-01-01

    Models for measuring individual response precision have been proposed for binary and graded responses. However, more continuous formats are quite common in personality measurement and are usually analyzed with the linear factor analysis model. This study extends the general Gaussian person-fluctuation model to the continuous-response case and…

  5. The Onion Model: Myth or Reality in the Field of Individual Differences Psychology?

    Science.gov (United States)

    Cools, Eva; Bellens, Kim

    2012-01-01

    To bring order in concepts related to individual learner differences, Curry (1983) designed the three-layered onion model. As this model provides an interesting way to distinguish related concepts--such as cognitive styles and approaches to studying--on the basis of their stability in learning situations, ample studies build further on this model.…

  6. Fish Individual-based Numerical Simulator (FINS): A particle-based model of juvenile salmonid movement and dissolved gas exposure history in the Columbia River Basin

    International Nuclear Information System (INIS)

    Scheibe, Timothy D.; Richmond, Marshall C.

    2002-01-01

    This paper describes a numerical model of juvenile salmonid migration in the Columbia and Snake Rivers. The model, called the Fish Individual-based Numerical Simulator or FINS, employs a discrete, particle-based approach to simulate the migration and history of exposure to dissolved gases of individual fish. FINS is linked to a two-dimensional (vertically-averaged) hydrodynamic simulator that quantifies local water velocity, temperature, and dissolved gas levels as a function of river flow rates and dam operations. Simulated gas exposure histories can be input to biological mortality models to predict the effects of various river configurations on fish injury and mortality due to dissolved gas supersaturation. Therefore, FINS serves as a critical linkage between hydrodynamic models of the river system and models of biological impacts. FINS was parameterized and validated based on observations of individual fish movements collected using radiotelemetry methods during 1997 and 1998 . A quasi-inverse approach was used to decouple fish swimming movements from advection with the local water velocity, allowing inference of time series of non-advective displacements of individual fish from the radiotelemetry data. Statistical analyses of these displacements are presented, and confirm that strong temporal correlation of fish swimming behavior persists in some cases over several hours. A correlated random-walk model was employed to simulate the observed migration behavior, and parameters of the model were estimated that lead to close correspondence between predictions and observations

  7. Additive gamma frailty models with applications to competing risks in related individuals

    DEFF Research Database (Denmark)

    Eriksson, Frank; Scheike, Thomas

    2015-01-01

    Epidemiological studies of related individuals are often complicated by the fact that follow-up on the event type of interest is incomplete due to the occurrence of other events. We suggest a class of frailty models with cause-specific hazards for correlated competing events in related individual...

  8. Analysis of habitat-selection rules using an individual-based model

    Science.gov (United States)

    Steven F. Railsback; Bret C. Harvey

    2002-01-01

    Abstract - Despite their promise for simulating natural complexity,individual-based models (IBMs) are rarely used for ecological research or resource management. Few IBMs have been shown to reproduce realistic patterns of behavior by individual organisms.To test our IBM of stream salmonids and draw conclusions about foraging theory,we analyzed the IBM ’s ability to...

  9. Micro-macro multilevel latent class models with multiple discrete individual-level variables

    NARCIS (Netherlands)

    Bennink, M.; Croon, M.A.; Kroon, B.; Vermunt, J.K.

    2016-01-01

    An existing micro-macro method for a single individual-level variable is extended to the multivariate situation by presenting two multilevel latent class models in which multiple discrete individual-level variables are used to explain a group-level outcome. As in the univariate case, the

  10. Simulation of Electric Faults in Doubly-Fed Induction Generators Employing Advanced Mathematical Modelling

    DEFF Research Database (Denmark)

    Martens, Sebastian; Mijatovic, Nenad; Holbøll, Joachim

    2015-01-01

    Efficient fault detection in generators often require prior knowledge of fault behavior, which can be obtained from theoretical analysis, often carried out by using discrete models of a given generator. Mathematical models are commonly represented in the DQ0 reference frame, which is convenient...... in many areas of electrical machine analysis. However, for fault investigations, the phase-coordinate representation has been found more suitable. This paper presents a mathematical model in phase coordinates of the DFIG with two parallel windings per rotor phase. The model has been implemented in Matlab...... and its properties in context of fault simulations and investigations has been investigated. Some of the most common faults have been simulated, namely broken rotor bars or windings, dynamic eccentricities and stator phase winding short circuits. These fault conditions propagate to the stator current...

  11. Predicting Individual Physiological Responses During Marksmanship Field Training Using an Updated SCENARIO-J Model

    National Research Council Canada - National Science Library

    Yokota, Miyo

    2004-01-01

    ...)) for individual variation and a metabolic rate (M) correction during downhill movements. This study evaluated the updated version of the model incorporating these new features, using a dataset collected during U.S. Marine Corps (USMC...

  12. Teachers’ individual action theories about competence-based education: the value of the cognitive apprenticeship model

    OpenAIRE

    Seezink, Audrey; Poell, Rob; Kirschner, Paul A.

    2009-01-01

    Seezink, A., Poell, R. F., & Kirschner, P. A. (2009). Teachers' individual action theories about competence-based education: The value of the cognitive apprenticeship model. Journal of Vocational Education & Training, 61, 203-215.

  13. Video-Quality Estimation Based on Reduced-Reference Model Employing Activity-Difference

    Science.gov (United States)

    Yamada, Toru; Miyamoto, Yoshihiro; Senda, Yuzo; Serizawa, Masahiro

    This paper presents a Reduced-reference based video-quality estimation method suitable for individual end-user quality monitoring of IPTV services. With the proposed method, the activity values for individual given-size pixel blocks of an original video are transmitted to end-user terminals. At the end-user terminals, the video quality of a received video is estimated on the basis of the activity-difference between the original video and the received video. Psychovisual weightings and video-quality score adjustments for fatal degradations are applied to improve estimation accuracy. In addition, low-bit-rate transmission is achieved by using temporal sub-sampling and by transmitting only the lower six bits of each activity value. The proposed method achieves accurate video quality estimation using only low-bit-rate original video information (15kbps for SDTV). The correlation coefficient between actual subjective video quality and estimated quality is 0.901 with 15kbps side information. The proposed method does not need computationally demanding spatial and gain-and-offset registrations. Therefore, it is suitable for real-time video-quality monitoring in IPTV services.

  14. Employing Predictive Spatial Models to Inform Conservation Planning for Seabirds in the Labrador Sea

    Directory of Open Access Journals (Sweden)

    David A. Fifield

    2017-05-01

    Full Text Available Seabirds are vulnerable to incidental harm from human activities in the ocean, and knowledge of their seasonal distribution is required to assess risk and effectively inform marine conservation planning. Significant hydrocarbon discoveries and exploration licenses in the Labrador Sea underscore the need for quantitative information on seabird seasonal distribution and abundance, as this region is known to provide important habitat for seabirds year-round. We explore the utility of density surface modeling (DSM to improve seabird information available for regional conservation and management decision making. We, (1 develop seasonal density surface models for seabirds in the Labrador Sea using data from vessel-based surveys (2006–2014; 13,783 linear km of surveys, (2 present measures of uncertainty in model predictions, (3 discuss how density surface models can inform conservation and management decision making, and 4 explore challenges and potential pitfalls associated with using these modeling procedures. Models predicted large areas of high seabird density in fall over continental shelf waters (max. ~80 birds·km−2 driven largely by the southward migration of murres (Uria spp. and dovekies (Alle alle from Arctic breeding colonies. The continental shelf break was also highlighted as an important habitat feature, with predictions of high seabird densities particularly during summer (max. ~70 birds·km−2. Notable concentrations of seabirds overlapped with several significant hydrocarbon discoveries on the continental shelf and large areas in the vicinity of the southern shelf break, which are in the early stages of exploration. Some, but not all, areas of high seabird density were within current Ecologically and Biologically Significant Area (EBSA boundaries. Building predictive spatial models required knowledge of Distance Sampling and GAMs, and significant investments of time and computational power—resource needs that are becoming more

  15. Chinese Basic Pension Substitution Rate: A Monte Carlo Demonstration of the Individual Account Model

    OpenAIRE

    Dong, Bei; Zhang, Ling; Lu, Xuan

    2008-01-01

    At the end of 2005, the State Council of China passed ”The Decision on adjusting the Individual Account of Basic Pension System”, which adjusted the individual account in the 1997 basic pension system. In this essay, we will analyze the adjustment above, and use Life Annuity Actuarial Theory to establish the basic pension substitution rate model. Monte Carlo simulation is also used to prove the rationality of the model. Some suggestions are put forward associated with the substitution rate ac...

  16. Perspectives of employability skills

    OpenAIRE

    ANNE LOUISE NEWTON

    2017-01-01

    The study investigated the different perspectives held by young people, employers and policy makers around Employability Skills and it examined how young people learnt these skills. This study draws young peoples’ perspectives into the research around Employability Skills and highlights the way in which social and cultural capital mediate their development. The research points to a model to re-vision employability skills which recognises the many ways in which they are learnt, over time a...

  17. Theoretical modelling of experimental diagnostic procedures employed during pre-dose dosimetry of quartz

    International Nuclear Information System (INIS)

    Pagonis, V.; Chen, R.; Kitis, G.

    2006-01-01

    The pre-dose technique in thermoluminescence (TL) is used for dating archaeological ceramics and for accident dosimetry. During routine applications of this technique, the sensitisation of the quartz samples is measured as a function of the annealing temperature, yielding the so-called thermal activation characteristic (TAC). The measurement of multiple TACs and the study of the effect of UV-radiation on the TL sensitivity of quartz are important analytical and diagnostic tools. In this paper, it is shown that a modified Zimmerman model for quartz can successfully model the experimental steps undertaken during a measurement of multiple TACs. (authors)

  18. Compatible Models of Carbon Content of Individual Trees on a Cunninghamia lanceolata Plantation in Fujian Province, China.

    Directory of Open Access Journals (Sweden)

    Lin Zhuo

    Full Text Available We tried to establish compatible carbon content models of individual trees for a Chinese fir (Cunninghamia lanceolata (Lamb. Hook. plantation from Fujian province in southeast China. In general, compatibility requires that the sum of components equal the whole tree, meaning that the sum of percentages calculated from component equations should equal 100%. Thus, we used multiple approaches to simulate carbon content in boles, branches, foliage leaves, roots and the whole individual trees. The approaches included (i single optimal fitting (SOF, (ii nonlinear adjustment in proportion (NAP and (iii nonlinear seemingly unrelated regression (NSUR. These approaches were used in combination with variables relating diameter at breast height (D and tree height (H, such as D, D2H, DH and D&H (where D&H means two separate variables in bivariate model. Power, exponential and polynomial functions were tested as well as a new general function model was proposed by this study. Weighted least squares regression models were employed to eliminate heteroscedasticity. Model performances were evaluated by using mean residuals, residual variance, mean square error and the determination coefficient. The results indicated that models with two dimensional variables (DH, D2H and D&H were always superior to those with a single variable (D. The D&H variable combination was found to be the most useful predictor. Of all the approaches, SOF could establish a single optimal model separately, but there were deviations in estimating results due to existing incompatibilities, while NAP and NSUR could ensure predictions compatibility. Simultaneously, we found that the new general model had better accuracy than others. In conclusion, we recommend that the new general model be used to estimate carbon content for Chinese fir and considered for other vegetation types as well.

  19. Employer branding

    OpenAIRE

    Mičková, Kateřina

    2008-01-01

    The demand for qualified employees is higher then the offering, both in Czech republic and internationally. Demand for specific skills, in addition to a greater demand for workforce generally, is making employee recruitment and retention much more difficult and expensive. Employer Branding claims to be an answer to this new challenge. This international concept focuses on developing an "employer brand" - mental image of a company as an employer. To achieve this, it is necessary to demonstrate...

  20. Individualizing Services, Individualizing Responsibility

    DEFF Research Database (Denmark)

    Garsten, Christina; Hollertz, Katarina; Jacobsson, Kerstin

    possibilities for individual voice, autonomy and self-determination in the local delivery of activation policy? What barriers do specific organisational models and practices imply for clients to choose, determine and access tailor-made programmes and services? What policy technologies are at work in governing......-oriented, and the normative demands placed on individuals appear increasingly totalizing, concerning the whole individual rather than the job-related aspects only. The paper is based on 23 in-depth interviews with individual clients as well as individual caseworkers and other professionals engaged in client-related work...

  1. University-Community Partnership Models: Employing Organizational Management Theories of Paradox and Strategic Contradiction

    Science.gov (United States)

    Bowers, Amanda M.

    2017-01-01

    University-Community (U-C) partnerships have the potential to respond to society's most pressing needs through engaged scholarship. Despite this promise, partnerships face paradoxical tensions and inherent contradictions that are often not fully addressed in U-C partnership models or frameworks, or in practice. This article seeks to explore the…

  2. Discontinuous growth modeling of adaptation to sleep setting changes: individual differences and age.

    Science.gov (United States)

    Bliese, Paul D; McGurk, Dennis; Thomas, Jeffrey L; Balkin, Thomas J; Wesensten, Nancy

    2007-05-01

    Biomedical devices allow investigators to collect long-term repeated measures data to study adaptation. We examined 26 d of actigraph sleep data and tested for individual differences in sleep patterns prior to, during, and after a transition of sleeping in garrison to sleeping in a field exercise setting. In addition, we examined whether the individual difference variable of participant age (a continuous variable ranging from 19-29 yr) was related to sleep patterns. Actigraph data was obtained from 77 cadets participating in a month-long military training program. At day 17, participants transitioned from sleeping in garrison to sleeping in a field exercise setting. A discontinuous growth model tested for individual differences in 1) overall sleep time, 2) garrison sleep slope, 3) the transition, and 4) the sleep slope during the field exercise setting. Individuals varied significantly in their overall sleep time, pattern of sleep in garrison, and the degree to which sleep decreased at the transition. The decline in sleep at the transition was related to participant age such that increases in age were associated with larger declines in sleep minutes. Individuals display significant variability in sleep patterns that can be detected using discontinuous growth models. The individual difference variable of participant age explains some of this variability. Much of the variability, however, remains unexplained. Future work will benefit from using discontinuous growth models to identify and model individual difference variables such as age when examining response patterns and transitions in data collected in applied field settings.

  3. Towards Linking 3D SAR and Lidar Models with a Spatially Explicit Individual Based Forest Model

    Science.gov (United States)

    Osmanoglu, B.; Ranson, J.; Sun, G.; Armstrong, A. H.; Fischer, R.; Huth, A.

    2017-12-01

    In this study, we present a parameterization of the FORMIND individual-based gap model (IBGM)for old growth Atlantic lowland rainforest in La Selva, Costa Rica for the purpose of informing multisensor remote sensing techniques for above ground biomass techniques. The model was successfully parameterized and calibrated for the study site; results show that the simulated forest reproduces the structural complexity of Costa Rican rainforest based on comparisons with CARBONO inventory plot data. Though the simulated stem numbers (378) slightly underestimated the plot data (418), particularly for canopy dominant intermediate shade tolerant trees and shade tolerant understory trees, overall there was a 9.7% difference. Aboveground biomass (kg/ha) showed a 0.1% difference between the simulated forest and inventory plot dataset. The Costa Rica FORMIND simulation was then used to parameterize a spatially explicit (3D) SAR and lidar backscatter models. The simulated forest stands were used to generate a Look Up Table as a tractable means to estimate aboveground forest biomass for these complex forests. Various combinations of lidar and radar variables were evaluated in the LUT inversion. To test the capability of future data for estimation of forest height and biomass, we considered data of 1) L- (or P-) band polarimetric data (backscattering coefficients of HH, HV and VV); 2) L-band dual-pol repeat-pass InSAR data (HH/HV backscattering coefficients and coherences, height of scattering phase center at HH and HV using DEM or surface height from lidar data as reference); 3) P-band polarimetric InSAR data (canopy height from inversion of PolInSAR data or use the coherences and height of scattering phase center at HH, HV and VV); 4) various height indices from waveform lidar data); and 5) surface and canopy top height from photon-counting lidar data. The methods for parameterizing the remote sensing models with the IBGM and developing Look Up Tables will be discussed. Results

  4. Developing an agent-based model on how different individuals solve complex problems

    Directory of Open Access Journals (Sweden)

    Ipek Bozkurt

    2015-01-01

    Full Text Available Purpose: Research that focuses on the emotional, mental, behavioral and cognitive capabilities of individuals has been abundant within disciplines such as psychology, sociology, and anthropology, among others. However, when facing complex problems, a new perspective to understand individuals is necessary. The main purpose of this paper is to develop an agent-based model and simulation to gain understanding on the decision-making and problem-solving abilities of individuals. Design/Methodology/approach: The micro-level analysis modeling and simulation paradigm Agent-Based Modeling Through the use of Agent-Based Modeling, insight is gained on how different individuals with different profiles deal with complex problems. Using previous literature from different bodies of knowledge, established theories and certain assumptions as input parameters, a model is built and executed through a computer simulation. Findings: The results indicate that individuals with certain profiles have better capabilities to deal with complex problems. Moderate profiles could solve the entire complex problem, whereas profiles within extreme conditions could not. This indicates that having a strong predisposition is not the ideal way when approaching complex problems, and there should always be a component from the other perspective. The probability that an individual may use these capabilities provided by the opposite predisposition provides to be a useful option. Originality/value: The originality of the present research stems from how individuals are profiled, and the model and simulation that is built to understand how they solve complex problems. The development of the agent-based model adds value to the existing body of knowledge within both social sciences, and modeling and simulation.

  5. Control method and system for hydraulic machines employing a dynamic joint motion model

    Science.gov (United States)

    Danko, George [Reno, NV

    2011-11-22

    A control method and system for controlling a hydraulically actuated mechanical arm to perform a task, the mechanical arm optionally being a hydraulically actuated excavator arm. The method can include determining a dynamic model of the motion of the hydraulic arm for each hydraulic arm link by relating the input signal vector for each respective link to the output signal vector for the same link. Also the method can include determining an error signal for each link as the weighted sum of the differences between a measured position and a reference position and between the time derivatives of the measured position and the time derivatives of the reference position for each respective link. The weights used in the determination of the error signal can be determined from the constant coefficients of the dynamic model. The error signal can be applied in a closed negative feedback control loop to diminish or eliminate the error signal for each respective link.

  6. Model-based document categorization employing semantic pattern analysis and local structure clustering

    Science.gov (United States)

    Fume, Kosei; Ishitani, Yasuto

    2008-01-01

    We propose a document categorization method based on a document model that can be defined externally for each task and that categorizes Web content or business documents into a target category in accordance with the similarity of the model. The main feature of the proposed method consists of two aspects of semantics extraction from an input document. The semantics of terms are extracted by the semantic pattern analysis and implicit meanings of document substructure are specified by a bottom-up text clustering technique focusing on the similarity of text line attributes. We have constructed a system based on the proposed method for trial purposes. The experimental results show that the system achieves more than 80% classification accuracy in categorizing Web content and business documents into 15 or 70 categories.

  7. Individual-based modelling of population growth and diffusion in discrete time.

    Directory of Open Access Journals (Sweden)

    Natalie Tkachenko

    Full Text Available Individual-based models (IBMs of human populations capture spatio-temporal dynamics using rules that govern the birth, behavior, and death of individuals. We explore a stochastic IBM of logistic growth-diffusion with constant time steps and independent, simultaneous actions of birth, death, and movement that approaches the Fisher-Kolmogorov model in the continuum limit. This model is well-suited to parallelization on high-performance computers. We explore its emergent properties with analytical approximations and numerical simulations in parameter ranges relevant to human population dynamics and ecology, and reproduce continuous-time results in the limit of small transition probabilities. Our model prediction indicates that the population density and dispersal speed are affected by fluctuations in the number of individuals. The discrete-time model displays novel properties owing to the binomial character of the fluctuations: in certain regimes of the growth model, a decrease in time step size drives the system away from the continuum limit. These effects are especially important at local population sizes of <50 individuals, which largely correspond to group sizes of hunter-gatherers. As an application scenario, we model the late Pleistocene dispersal of Homo sapiens into the Americas, and discuss the agreement of model-based estimates of first-arrival dates with archaeological dates in dependence of IBM model parameter settings.

  8. Stochastic Individual-Based Modeling of Bacterial Growth and Division Using Flow Cytometry

    Directory of Open Access Journals (Sweden)

    Míriam R. García

    2018-01-01

    Full Text Available A realistic description of the variability in bacterial growth and division is critical to produce reliable predictions of safety risks along the food chain. Individual-based modeling of bacteria provides the theoretical framework to deal with this variability, but it requires information about the individual behavior of bacteria inside populations. In this work, we overcome this problem by estimating the individual behavior of bacteria from population statistics obtained with flow cytometry. For this objective, a stochastic individual-based modeling framework is defined based on standard assumptions during division and exponential growth. The unknown single-cell parameters required for running the individual-based modeling simulations, such as cell size growth rate, are estimated from the flow cytometry data. Instead of using directly the individual-based model, we make use of a modified Fokker-Plank equation. This only equation simulates the population statistics in function of the unknown single-cell parameters. We test the validity of the approach by modeling the growth and division of Pediococcus acidilactici within the exponential phase. Estimations reveal the statistics of cell growth and division using only data from flow cytometry at a given time. From the relationship between the mother and daughter volumes, we also predict that P. acidilactici divide into two successive parallel planes.

  9. Using decision models to enhance investigations of individual differences in cognitive neuroscience

    Directory of Open Access Journals (Sweden)

    Corey N White

    2016-02-01

    Full Text Available There is great interest in relating individual differences in cognitive processing to activation of neural systems. The general process involves relating measures of task performance like reaction times or accuracy to brain activity to identify individual differences in neural processing. One limitation of this approach is that measures like reaction times can be affected by multiple components of processing. For instance, some individuals might have higher accuracy in a memory task because they respond more cautiously, not because they have better memory. Computational models of decision making, like the drift-diffusion model and the linear ballistic accumulator model, provide a potential solution to this problem. They can be fitted to data from individual participants to disentangle the effects of the different processes driving behavior. In this sense the models can provide cleaner measures of the processes of interest, and enhance our understanding of how neural activity varies across individuals or populations. The advantages of this model-based approach to investigating individual differences in neural activity are discussed with recent examples of how this method can improve our understanding of the brain-behavior relationship.

  10. Power system stability enhancement employing controllers based on a versatile modeling

    Science.gov (United States)

    Chung, Chi Yung

    Rapid advances in power electronics have made it both practicable and economic to design powerful thyristor-controlled devices, such as Flexible AC Transmission Systems (FACTS), for stability enhancements. The discrepancies of existing modeling approaches have limited the feasibility of handling these devices or designing its damping controller. In this thesis, a versatile and generalized approach to model standard power system components is proposed. The more systematic and realistic representation, accompanied by the development of powerful eigenvalue-analysis techniques, facilitates the study of small signal stability (monotonic and oscillatory) of the power systems. In monotonic stability study, the effect of exciter and governor is critically reviewed based on the exploitation of eigenvalues, modal and sensitivity analyses over a wide range of operating conditions. In oscillatory stability study, a common FACTS device, the static var compensator (SVC), is used to improve system damping. This study reveals the inadequacy of many conventional methodologies in SVC design since they have ignored (or cannot handle) some important factors such as SVC mode instability and robustness of the power system. Two approaches, combined sensitivities and Hinfinity algorithms, are introduced to solve these limitations. Finally, an extended Hinfinity algorithm, which is applied to PSS design and successfully solves certain limitations of the existing H infinity based PSS design, is also presented. Although these studies are developed on selected controller devices or typical systems for convenience of discussion, extension to more complex systems can be dealt with in a similar way because of the versatility of the proposed modeling methodology.

  11. Structure and sensitivity analysis of individual-based predator–prey models

    International Nuclear Information System (INIS)

    Imron, Muhammad Ali; Gergs, Andre; Berger, Uta

    2012-01-01

    The expensive computational cost of sensitivity analyses has hampered the use of these techniques for analysing individual-based models in ecology. A relatively cheap computational cost, referred to as the Morris method, was chosen to assess the relative effects of all parameters on the model’s outputs and to gain insights into predator–prey systems. Structure and results of the sensitivity analysis of the Sumatran tiger model – the Panthera Population Persistence (PPP) and the Notonecta foraging model (NFM) – were compared. Both models are based on a general predation cycle and designed to understand the mechanisms behind the predator–prey interaction being considered. However, the models differ significantly in their complexity and the details of the processes involved. In the sensitivity analysis, parameters that directly contribute to the number of prey items killed were found to be most influential. These were the growth rate of prey and the hunting radius of tigers in the PPP model as well as attack rate parameters and encounter distance of backswimmers in the NFM model. Analysis of distances in both of the models revealed further similarities in the sensitivity of the two individual-based models. The findings highlight the applicability and importance of sensitivity analyses in general, and screening design methods in particular, during early development of ecological individual-based models. Comparison of model structures and sensitivity analyses provides a first step for the derivation of general rules in the design of predator–prey models for both practical conservation and conceptual understanding. - Highlights: ► Structure of predation processes is similar in tiger and backswimmer model. ► The two individual-based models (IBM) differ in space formulations. ► In both models foraging distance is among the sensitive parameters. ► Morris method is applicable for the sensitivity analysis even of complex IBMs.

  12. Who will have Sustainable Employment After a Back Injury? The Development of a Clinical Prediction Model in a Cohort of Injured Workers

    DEFF Research Database (Denmark)

    Shearer, Heather M.; Côté, Pierre; Boyle, Eleanor

    2017-01-01

    intensity, mental health-related quality of life, claim litigation and employer type (c-index = 0.77). At 6 months, sustainable employment was predicted by physical and mental health-related quality of life, claim litigation and employer type (c-index = 0.77). Adding health-related and work......-related variables to models improved predictive accuracy by 8.5 and 10 % at 1 and 6 months respectively. Conclusion We developed clinically-relevant models to predict sustainable employment in injured workers who made a workers’ compensation claim for LBP. Inquiring about back pain intensity, physical and mental......Purpose Our objective was to develop a clinical prediction model to identify workers with sustainable employment following an episode of work-related low back pain (LBP). Methods We used data from a cohort study of injured workers with incident LBP claims in the USA to predict employment patterns 1...

  13. Industry Employment

    Science.gov (United States)

    Occupational Outlook Quarterly, 2012

    2012-01-01

    This article illustrates projected employment change by industry and industry sector over 2010-20 decade. Workers are grouped into an industry according to the type of good produced or service provided by the establishment for which they work. Industry employment projections are shown in terms of numeric change (growth or decline in the total…

  14. D Recording for 2d Delivering - the Employment of 3d Models for Studies and Analyses -

    Science.gov (United States)

    Rizzi, A.; Baratti, G.; Jiménez, B.; Girardi, S.; Remondino, F.

    2011-09-01

    In the last years, thanks to the advances of surveying sensors and techniques, many heritage sites could be accurately replicated in digital form with very detailed and impressive results. The actual limits are mainly related to hardware capabilities, computation time and low performance of personal computer. Often, the produced models are not visible on a normal computer and the only solution to easily visualized them is offline using rendered videos. This kind of 3D representations is useful for digital conservation, divulgation purposes or virtual tourism where people can visit places otherwise closed for preservation or security reasons. But many more potentialities and possible applications are available using a 3D model. The problem is the ability to handle 3D data as without adequate knowledge this information is reduced to standard 2D data. This article presents some surveying and 3D modeling experiences within the APSAT project ("Ambiente e Paesaggi dei Siti d'Altura Trentini", i.e. Environment and Landscapes of Upland Sites in Trentino). APSAT is a multidisciplinary project funded by the Autonomous Province of Trento (Italy) with the aim documenting, surveying, studying, analysing and preserving mountainous and hill-top heritage sites located in the region. The project focuses on theoretical, methodological and technological aspects of the archaeological investigation of mountain landscape, considered as the product of sequences of settlements, parcelling-outs, communication networks, resources, and symbolic places. The mountain environment preserves better than others the traces of hunting and gathering, breeding, agricultural, metallurgical, symbolic activities characterised by different lengths and environmental impacts, from Prehistory to the Modern Period. Therefore the correct surveying and documentation of this heritage sites and material is very important. Within the project, the 3DOM unit of FBK is delivering all the surveying and 3D material to

  15. Crustal Models Assessment in Western Part of Romania Employing Active Seismic and Seismologic Methods

    Science.gov (United States)

    Bala, Andrei; Toma-Danila, Dragos; Tataru, Dragos; Grecu, Bogdan

    2017-12-01

    In the years 1999 - 2000 two regional seismic refraction lines were performed within a close cooperation with German partners from University of Karlsruhe. One of these lines is Vrancea 2001, with 420 km in length, almost half of them recorded in Transylvanian Basin. The structure of the crust along the seismic line revealed a very complicated crustal structure beginning with Eastern Carpathians and continuing in the Transylvanian Basin until Medias. As a result of the development of the National Seismic Network in the last ten years, more than 100 permanent broadband stations are now continuously operating in Romania. Complementary to this national dataset, maintained and developed in the National Institute for Earth Physics, new data emerged from the temporary seismologic networks established during the joint projects with European partners in the last decades. The data gathered so far is valuable both for seismology purposes and crustal structure studies, especially for the western part of the country, where this kind of data were sparse until now. Between 2009 and 2011, a new reference model for the Earth’s crust and mantle of the European Plate was defined through the NERIES project from existing data and models. The database gathered from different kind of measurements in Transylvanian Basin and eastern Pannonian Basin were included in this NERIES model and an improved and upgraded model of the Earth crust emerged for western part of Romania. Although the dataset has its origins in several periods over the last 50 years, the results are homogeneous and they improve and strengthen our image about the depth of the principal boundaries in the crust. In the last chapter two maps regarding these boundaries are constructed, one for mid-crustal boundary and one for Moho. They were build considering all the punctual information available from different sources in active seismic and seismology which are introduced in the general maps from the NERIES project for

  16. Towards intelligent diagnostic system employing integration of mathematical and engineering model

    Science.gov (United States)

    Isa, Nor Ashidi Mat

    2015-05-01

    The development of medical diagnostic system has been one of the main research fields during years. The goal of the medical diagnostic system is to place a nosological system that could ease the diagnostic evaluation normally performed by scientists and doctors. Efficient diagnostic evaluation is essentials and requires broad knowledge in order to improve conventional diagnostic system. Several approaches on developing the medical diagnostic system have been designed and tested since the earliest 60s. Attempts on improving their performance have been made which utilizes the fields of artificial intelligence, statistical analyses, mathematical model and engineering theories. With the availability of the microcomputer and software development as well as the promising aforementioned fields, medical diagnostic prototypes could be developed. In general, the medical diagnostic system consists of several stages, namely the 1) data acquisition, 2) feature extraction, 3) feature selection, and 4) classifications stages. Data acquisition stage plays an important role in converting the inputs measured from the real world physical conditions to the digital numeric values that can be manipulated by the computer system. One of the common medical inputs could be medical microscopic images, radiographic images, magnetic resonance image (MRI) as well as medical signals such as electrocardiogram (ECG) and electroencephalogram (EEG). Normally, the scientist or doctors have to deal with myriad of data and redundant to be processed. In order to reduce the complexity of the diagnosis process, only the significant features of the raw data such as peak value of the ECG signal or size of lesion in the mammogram images will be extracted and considered in the subsequent stages. Mathematical models and statistical analyses will be performed to select the most significant features to be classified. The statistical analyses such as principal component analysis and discriminant analysis as well

  17. Towards intelligent diagnostic system employing integration of mathematical and engineering model

    International Nuclear Information System (INIS)

    Isa, Nor Ashidi Mat

    2015-01-01

    The development of medical diagnostic system has been one of the main research fields during years. The goal of the medical diagnostic system is to place a nosological system that could ease the diagnostic evaluation normally performed by scientists and doctors. Efficient diagnostic evaluation is essentials and requires broad knowledge in order to improve conventional diagnostic system. Several approaches on developing the medical diagnostic system have been designed and tested since the earliest 60s. Attempts on improving their performance have been made which utilizes the fields of artificial intelligence, statistical analyses, mathematical model and engineering theories. With the availability of the microcomputer and software development as well as the promising aforementioned fields, medical diagnostic prototypes could be developed. In general, the medical diagnostic system consists of several stages, namely the 1) data acquisition, 2) feature extraction, 3) feature selection, and 4) classifications stages. Data acquisition stage plays an important role in converting the inputs measured from the real world physical conditions to the digital numeric values that can be manipulated by the computer system. One of the common medical inputs could be medical microscopic images, radiographic images, magnetic resonance image (MRI) as well as medical signals such as electrocardiogram (ECG) and electroencephalogram (EEG). Normally, the scientist or doctors have to deal with myriad of data and redundant to be processed. In order to reduce the complexity of the diagnosis process, only the significant features of the raw data such as peak value of the ECG signal or size of lesion in the mammogram images will be extracted and considered in the subsequent stages. Mathematical models and statistical analyses will be performed to select the most significant features to be classified. The statistical analyses such as principal component analysis and discriminant analysis as well

  18. Towards intelligent diagnostic system employing integration of mathematical and engineering model

    Energy Technology Data Exchange (ETDEWEB)

    Isa, Nor Ashidi Mat [Imaging and Intelligent System Research Team (ISRT), School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2015-05-15

    The development of medical diagnostic system has been one of the main research fields during years. The goal of the medical diagnostic system is to place a nosological system that could ease the diagnostic evaluation normally performed by scientists and doctors. Efficient diagnostic evaluation is essentials and requires broad knowledge in order to improve conventional diagnostic system. Several approaches on developing the medical diagnostic system have been designed and tested since the earliest 60s. Attempts on improving their performance have been made which utilizes the fields of artificial intelligence, statistical analyses, mathematical model and engineering theories. With the availability of the microcomputer and software development as well as the promising aforementioned fields, medical diagnostic prototypes could be developed. In general, the medical diagnostic system consists of several stages, namely the 1) data acquisition, 2) feature extraction, 3) feature selection, and 4) classifications stages. Data acquisition stage plays an important role in converting the inputs measured from the real world physical conditions to the digital numeric values that can be manipulated by the computer system. One of the common medical inputs could be medical microscopic images, radiographic images, magnetic resonance image (MRI) as well as medical signals such as electrocardiogram (ECG) and electroencephalogram (EEG). Normally, the scientist or doctors have to deal with myriad of data and redundant to be processed. In order to reduce the complexity of the diagnosis process, only the significant features of the raw data such as peak value of the ECG signal or size of lesion in the mammogram images will be extracted and considered in the subsequent stages. Mathematical models and statistical analyses will be performed to select the most significant features to be classified. The statistical analyses such as principal component analysis and discriminant analysis as well

  19. Driving-forces model on individual behavior in scenarios considering moving threat agents

    Science.gov (United States)

    Li, Shuying; Zhuang, Jun; Shen, Shifei; Wang, Jia

    2017-09-01

    The individual behavior model is a contributory factor to improve the accuracy of agent-based simulation in different scenarios. However, few studies have considered moving threat agents, which often occur in terrorist attacks caused by attackers with close-range weapons (e.g., sword, stick). At the same time, many existing behavior models lack validation from cases or experiments. This paper builds a new individual behavior model based on seven behavioral hypotheses. The driving-forces model is an extension of the classical social force model considering scenarios including moving threat agents. An experiment was conducted to validate the key components of the model. Then the model is compared with an advanced Elliptical Specification II social force model, by calculating the fitting errors between the simulated and experimental trajectories, and being applied to simulate a specific circumstance. Our results show that the driving-forces model reduced the fitting error by an average of 33.9% and the standard deviation by an average of 44.5%, which indicates the accuracy and stability of the model in the studied situation. The new driving-forces model could be used to simulate individual behavior when analyzing the risk of specific scenarios using agent-based simulation methods, such as risk analysis of close-range terrorist attacks in public places.

  20. VIA Employability

    DEFF Research Database (Denmark)

    Andersen, Henrik Mariendal

    2017-01-01

    The fact that students develop employability during their education is a key point for educational institutions and the focus on this issue has never been greater. This project looks into personal experience from VIA-graduates of "developing their employability" during the education and how it......’s realized at the entrance to the labor market and in the future career. The purpose is to find opportunities to improve employability-developing activities and to adapt it to specific needs from the students. Based on a number of qualitative interviews and personality tests of the graduates, an increased...... personal approach is proposed in the agenda of employability. And ensure a wide range of offers, that appeal to multiple and differentiated personal and professional approaches to employability....

  1. Probabilistic Inference: Task Dependency and Individual Differences of Probability Weighting Revealed by Hierarchical Bayesian Modeling.

    Science.gov (United States)

    Boos, Moritz; Seer, Caroline; Lange, Florian; Kopp, Bruno

    2016-01-01

    Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian modeling techniques. A classic urn-ball paradigm served as experimental strategy, involving a factorial two (prior probabilities) by two (likelihoods) design. Five computational models of cognitive processes were compared with the observed behavior. Parameter-free Bayesian posterior probabilities and parameter-free base rate neglect provided inadequate models of probabilistic inference. The introduction of distorted subjective probabilities yielded more robust and generalizable results. A general class of (inverted) S-shaped probability weighting functions had been proposed; however, the possibility of large differences in probability distortions not only across experimental conditions, but also across individuals, seems critical for the model's success. It also seems advantageous to consider individual differences in parameters of probability weighting as being sampled from weakly informative prior distributions of individual parameter values. Thus, the results from hierarchical Bayesian modeling converge with previous results in revealing that probability weighting parameters show considerable task dependency and individual differences. Methodologically, this work exemplifies the usefulness of hierarchical Bayesian modeling techniques for cognitive psychology. Theoretically, human probabilistic inference might be best described as the application of individualized strategic policies for Bayesian belief revision.

  2. Validation of simplified centre of mass models during gait in individuals with chronic stroke.

    Science.gov (United States)

    Huntley, Andrew H; Schinkel-Ivy, Alison; Aqui, Anthony; Mansfield, Avril

    2017-10-01

    The feasibility of using a multiple segment (full-body) kinematic model in clinical gait assessment is difficult when considering obstacles such as time and cost constraints. While simplified gait models have been explored in healthy individuals, no such work to date has been conducted in a stroke population. The aim of this study was to quantify the errors of simplified kinematic models for chronic stroke gait assessment. Sixteen individuals with chronic stroke (>6months), outfitted with full body kinematic markers, performed a series of gait trials. Three centre of mass models were computed: (i) 13-segment whole-body model, (ii) 3 segment head-trunk-pelvis model, and (iii) 1 segment pelvis model. Root mean squared error differences were compared between models, along with correlations to measures of stroke severity. Error differences revealed that, while both models were similar in the mediolateral direction, the head-trunk-pelvis model had less error in the anteroposterior direction and the pelvis model had less error in the vertical direction. There was some evidence that the head-trunk-pelvis model error is influenced in the mediolateral direction for individuals with more severe strokes, as a few significant correlations were observed between the head-trunk-pelvis model and measures of stroke severity. These findings demonstrate the utility and robustness of the pelvis model for clinical gait assessment in individuals with chronic stroke. Low error in the mediolateral and vertical directions is especially important when considering potential stability analyses during gait for this population, as lateral stability has been previously linked to fall risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Taking individual scaling differences into account by analyzing profile data with the Mixed Assessor Model

    DEFF Research Database (Denmark)

    Brockhoff, Per Bruun; Schlich, Pascal; Skovgaard, Ib

    2015-01-01

    Scale range differences between individual assessors will often constitute a non-trivial part of the assessor-by-product interaction in sensory profile data (Brockhoff, 2003, 1998; Brockhoff and Skovgaard, 1994). We suggest a new mixed model ANOVA analysis approach, the Mixed Assessor Model (MAM...

  4. An individual-based model of Zebrafish population dynamics accounting for energy dynamics

    DEFF Research Database (Denmark)

    Beaudouin, Remy; Goussen, Benoit; Piccini, Benjamin

    2015-01-01

    Developing population dynamics models for zebrafish is crucial in order to extrapolate from toxicity data measured at the organism level to biological levels relevant to support and enhance ecological risk assessment. To achieve this, a dynamic energy budget for individual zebrafish (DEB model) w...

  5. Influence of Erroneous Patient Records on Population Pharmacokinetic Modeling and Individual Bayesian Estimation

    NARCIS (Netherlands)

    van der Meer, Aize Franciscus; Touw, Daniel J.; Marcus, Marco A. E.; Neef, Cornelis; Proost, Johannes H.

    2012-01-01

    Background: Observational data sets can be used for population pharmacokinetic (PK) modeling. However, these data sets are generally less precisely recorded than experimental data sets. This article aims to investigate the influence of erroneous records on population PK modeling and individual

  6. The Limit Behavior of a Stochastic Logistic Model with Individual Time-Dependent Rates

    Directory of Open Access Journals (Sweden)

    Yilun Shang

    2013-01-01

    Full Text Available We investigate a variant of the stochastic logistic model that allows individual variation and time-dependent infection and recovery rates. The model is described as a heterogeneous density dependent Markov chain. We show that the process can be approximated by a deterministic process defined by an integral equation as the population size grows.

  7. Enthalpy-based equation of state for highly porous materials employing modified soft sphere fluid model

    Science.gov (United States)

    Nayak, Bishnupriya; Menon, S. V. G.

    2018-01-01

    Enthalpy-based equation of state based on a modified soft sphere model for the fluid phase, which includes vaporization and ionization effects, is formulated for highly porous materials. Earlier developments and applications of enthalpy-based approach had not accounted for the fact that shocked states of materials with high porosity (e.g., porosity more than two for Cu) are in the expanded fluid region. We supplement the well known soft sphere model with a generalized Lennard-Jones formula for the zero temperature isotherm, with parameters determined from cohesive energy, specific volume and bulk modulus of the solid at normal condition. Specific heats at constant pressure, ionic and electronic enthalpy parameters and thermal excitation effects are calculated using the modified approach and used in the enthalpy-based equation of state. We also incorporate energy loss from the shock due to expansion of shocked material in calculating porous Hugoniot. Results obtained for Cu, even up to initial porosities ten, show good agreement with experimental data.

  8. Workplace accommodations for employees with disabilities: A multilevel model of employer decision-making.

    Science.gov (United States)

    Telwatte, Apsara; Anglim, Jeromy; Wynton, Sarah K A; Moulding, Richard

    2017-02-01

    Existing research suggests that the decision to grant or deny workplace accommodations for people with disabilities is influenced by a range of legal and nonlegal factors. However, less is known about how these factors operate at the within-person level. Thus, we proposed and tested a multilevel model of the accommodation decision-making process, which we applied to better understand why people with psychological disabilities often experience greater challenges in obtaining accommodations. A sample of 159 Australian adults, composed mostly of managers and HR professionals, read 12 vignettes involving requests for accommodations from existing employees. The requests differed in whether they were for psychological or physical disabilities. For each vignette, participants rated their empathy with the employee, the legitimacy of the employee's disability, the necessity for productivity, the perceived cost, and the reasonableness, and indicated whether they would grant the accommodation. Multilevel modeling indicated that greater empathy, legitimacy, and necessity, and lower perceived cost predicted perceptions of greater reasonableness and greater granting. Accommodation requests from employees with psychological disabilities were seen as less reasonable and were less likely to be granted; much of this effect seemed to be driven by perceptions that such accommodations were less necessary for productivity. Ratings on accommodations were influenced both by general between-person tendencies and within-person appraisals of particular scenarios. The study points to a need for organizations to more clearly establish guidelines for how decision-makers should fairly evaluate accommodation requests for employees with psychological disabilities and disability more broadly. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Modelling and modal properties of the railway vehicle bogie with two individual wheelset drives

    Directory of Open Access Journals (Sweden)

    Zeman V.

    2007-10-01

    Full Text Available The paper deals with mathematical modelling of vibration and modal analysis of two-axled bogie of a railway vehicle. In comparison with recent publications introducing mathematical models of an individual wheelset drive, this paper is focused on modelling of complex bogie vibration. The bogie frame is linked by primary suspension to the two wheelset drives with hollow shafts and by secondary suspension to the car body. The method is based on the system decomposition into three subsystems – two individual wheelset drives including the mass of the rail and the bogie frame coupled with a half of the car body – and on modelling of couplings among subsystems. The eigenvalues of a linearized autonomous model and stability conditions are investigated in dependence on longitudinal creepage and forward velocity of the railway vehicle. The nonlinear model will be used for investigating the dynamic loading of bogie components caused by different types of excitation.

  10. A Factor-Analytic Model for Assessing Individual Differences in Response Scale Usage.

    Science.gov (United States)

    Ferrando, Pere J

    2014-01-01

    This article proposes a factor-analytic model, intended for graded-response or continuous-response personality and attitude items, which includes an additional multiplicative person parameter that models the individual's response mapping process. The model, which is a modification of Spearman's (1904) factor analysis (FA) model, is parameterized as both an FA model and an item response theory (IRT) model and is fully developed to the extent that it can be used in applications. Procedures for (a) calibrating the items and assessing data fit, (b) obtaining individual estimates of both person parameters, (c) determining measurement precision, and (d) assessing differential predictability are proposed and discussed. The potential advantages of the proposal, its practical relevance, and its relations with other approaches are also discussed. Its functioning is assessed with a simulation study and 3 empirical examples in the personality domain.

  11. Employment of Lithuanian Statistical Data Into Tax-Benefit Micro-Simulation Models

    Directory of Open Access Journals (Sweden)

    Viginta Ivaškaitė-Tamošiūnė

    2012-07-01

    Full Text Available In this study, we aim to assess the “best fit” of the existing Lithuanian micro-datasets for constructing a national micro-simulation model. Specifically, we compare and evaluate the potential of two (state level representative micro-data surveys in terms of their potential to simulate Lithuanian (direct taxes, social contributions and social benefits. Both selected datasets contain rich information on the socio-economic and demographical conditions of the country: the Household Budget Survey (HBS for the years 2004 and 2005 and the European Community Statistics on Income and Living Conditions (EU-SILC in Lithuania for the year 2005. The selected databases offer the most comprehensive range of income and other socio-demographic attributes, needed for simulation of tax and contributions’ payers/amounts and benefits’ recipients/amounts. The evaluation of the dataset capacity to simulate these measures is done by a comparative statistical analysis. Among the comparative categories are definitions (of households, incomes, survey collection modes, level of aggregation of various variables, demographic and incomes variables and corresponding numbers (amounts.The comparative analysis of the HBS and EU-SILC datasets shows, that despite embedded differences and shortages regarding simulation capacities of both surveys, these datasets contain valuable and sufficient information for the purpose of simulation of Lithuanian tax-benefit policies.In general a conclusion could be drawn, that HBS offers higher possibilities of simulating the Lithuanian tax-benefit system. This dataset contains more detailed national income categories (i.e. recipients of maternity/paternity insurance, diverse pensions, etc.— information on which is not available in the EU-SILC. The latter dataset does not contain national policy system specific components, but offer information on income aggregates, such all old-age pensions, social exclusion benefits, etc. Additionally

  12. Probabilistic inference: Task dependency and individual differences of probability weighting revealed by hierarchical Bayesian modelling

    Directory of Open Access Journals (Sweden)

    Moritz eBoos

    2016-05-01

    Full Text Available Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian modelling techniques. A classic urn-ball paradigm served as experimental strategy, involving a factorial two (prior probabilities by two (likelihoods design. Five computational models of cognitive processes were compared with the observed behaviour. Parameter-free Bayesian posterior probabilities and parameter-free base rate neglect provided inadequate models of probabilistic inference. The introduction of distorted subjective probabilities yielded more robust and generalizable results. A general class of (inverted S-shaped probability weighting functions had been proposed; however, the possibility of large differences in probability distortions not only across experimental conditions, but also across individuals, seems critical for the model’s success. It also seems advantageous to consider individual differences in parameters of probability weighting as being sampled from weakly informative prior distributions of individual parameter values. Thus, the results from hierarchical Bayesian modelling converge with previous results in revealing that probability weighting parameters show considerable task dependency and individual differences. Methodologically, this work exemplifies the usefulness of hierarchical Bayesian modelling techniques for cognitive psychology. Theoretically, human probabilistic inference might be best described as the application of individualized strategic policies for Bayesian belief revision.

  13. Toward real-time diffuse optical tomography: accelerating light propagation modeling employing parallel computing on GPU and CPU

    Science.gov (United States)

    Doulgerakis, Matthaios; Eggebrecht, Adam; Wojtkiewicz, Stanislaw; Culver, Joseph; Dehghani, Hamid

    2017-12-01

    Parameter recovery in diffuse optical tomography is a computationally expensive algorithm, especially when used for large and complex volumes, as in the case of human brain functional imaging. The modeling of light propagation, also known as the forward problem, is the computational bottleneck of the recovery algorithm, whereby the lack of a real-time solution is impeding practical and clinical applications. The objective of this work is the acceleration of the forward model, within a diffusion approximation-based finite-element modeling framework, employing parallelization to expedite the calculation of light propagation in realistic adult head models. The proposed methodology is applicable for modeling both continuous wave and frequency-domain systems with the results demonstrating a 10-fold speed increase when GPU architectures are available, while maintaining high accuracy. It is shown that, for a very high-resolution finite-element model of the adult human head with ˜600,000 nodes, consisting of heterogeneous layers, light propagation can be calculated at ˜0.25 s/excitation source.

  14. A Nonlinear Mixed Effects Model for the Prediction of Natural Gas Consumption by Individual Customers

    Czech Academy of Sciences Publication Activity Database

    Brabec, Marek; Konár, Ondřej; Pelikán, Emil; Malý, Marek

    2008-01-01

    Roč. 24, č. 4 (2008), s. 659-678 ISSN 0169-2070 R&D Projects: GA AV ČR 1ET400300513 Institutional research plan: CEZ:AV0Z10300504 Keywords : individual gas consumption * nonlinear mixed effects model * ARIMAX * ARX * generalized linear mixed model * conditional modeling Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use Impact factor: 1.685, year: 2008

  15. Employment of Lithuanian Statistical Data Into Tax-Benefit Micro-Simulation Models

    Directory of Open Access Journals (Sweden)

    Viginta Ivaškaitė-Tamošiūnė

    2013-01-01

    Full Text Available In this study, we aim to assess the “best fit” of the existing Lithuanian micro-datasets for constructing a national micro-simulation model. Specifically, we compare and evaluate the potential of two (state level representative micro-data surveys in terms of their potential to simulate Lithuanian (direct taxes, social contributions and social benefits. Both selected datasets contain rich information on the socio-economic and demographical conditions of the country: the Household Budget Survey (HBS for the years 2004 and 2005 and the European Community Statistics on Income and Living Conditions (EU-SILC in Lithuania for the year 2005. The selected databases offer the most comprehensive range of income and other socio-demographic attributes, needed for simulation of tax and contributions’ payers/amounts and benefits’ recipients/amounts. The evaluation of the dataset capacity to simulate these measures is done by a comparative statistical analysis. Among the comparative categories are definitions (of households, incomes, survey collection modes, level of aggregation of various variables, demographic and incomes variables and corresponding numbers (amounts. The comparative analysis of the HBS and EU-SILC datasets shows, that despite embedded differences and shortages regarding simulation capacities of both surveys, these datasets contain valuable and sufficient information for the purpose of simulation of Lithuanian tax-benefit policies. In general a conclusion could be drawn, that HBS offers higher possibilities of simulating the Lithuanian tax-benefit system. This dataset contains more detailed national income categories (i.e. recipients of maternity/paternity insurance, diverse pensions, etc.— information on which is not available in the EU-SILC. The latter dataset does not contain national policy system specific components, but offer information on income aggregates, such all old-age pensions, social exclusion benefits, etc

  16. Lipoprotein transport in the metabolic syndrome: pathophysiological and interventional studies employing stable isotopy and modelling methods.

    Science.gov (United States)

    Chan, Dick C; Barrett, P Hugh R; Watts, Gerald F

    2004-09-01

    The accompanying review in this issue of Clinical Science [Chan, Barrett and Watts (2004) Clin. Sci. 107, 221-232] presented an overview of lipoprotein physiology and the methodologies for stable isotope kinetic studies. The present review focuses on our understanding of the dysregulation and therapeutic regulation of lipoprotein transport in the metabolic syndrome based on the application of stable isotope and modelling methods. Dysregulation of lipoprotein metabolism in metabolic syndrome may be due to a combination of overproduction of VLDL [very-LDL (low-density lipoprotein)]-apo (apolipoprotein) B-100, decreased catabolism of apoB-containing particles and increased catabolism of HDL (high-density lipoprotein)-apoA-I particles. These abnormalities may be consequent on a global metabolic effect of insulin resistance, partly mediated by depressed plasma adiponectin levels, that collectively increases the flux of fatty acids from adipose tissue to the liver, the accumulation of fat in the liver and skeletal muscle, the hepatic secretion of VLDL-triacylglycerols and the remodelling of both LDL (low-density lipoprotein) and HDL particles in the circulation. These lipoprotein defects are also related to perturbations in both lipolytic enzymes and lipid transfer proteins. Our knowledge of the pathophysiology of lipoprotein metabolism in the metabolic syndrome is well complemented by extensive cell biological data. Nutritional modifications may favourably alter lipoprotein transport in the metabolic syndrome by collectively decreasing the hepatic secretion of VLDL-apoB and the catabolism of HDL-apoA-I, as well as by potentially increasing the clearance of LDL-apoB. Several pharmacological treatments, such as statins, fibrates or fish oils, can also correct the dyslipidaemia by diverse kinetic mechanisms of action, including decreased secretion and increased catabolism of apoB, as well as increased secretion and decreased catabolism of apoA-I. The complementary

  17. THE DYNAMIC MODEL FOR CONTROL OF STUDENT’S LEARNING INDIVIDUAL TRAJECTORY

    Directory of Open Access Journals (Sweden)

    A. A. Mitsel

    2015-01-01

    Full Text Available In connection with the transition of the educational system to a competence-oriented approach, the problem of learning outcomes assessment and creating an individual learning trajectory of a student has become relevant. Its solution requires the application of modern information technologies. The third generation of Federal state educational standards of higher professional education (FSES HPE defines the requirements for the results of Mastering the basic educational programs (BEP. According to FSES HPE up to 50% of subjects have a variable character, i.e. depend on the choice of a student. It significantly influences on the results of developing various competencies. The problem of forming student’s learning trajectory is analyzed in general and the choice of an individual direction was studied in details. Various methods, models and algorithms of the student’s individual learning trajectory formation were described. The analysis of the model of educational process organization in terms of individual approach makes it possible to develop a decision support system (DSS. DSS is a set of interrelated programs and data used for analysis of situation, development of alternative solutions and selection of the most acceptable alternative. DSSs are often used when building individual learning path, because this task can be considered as a discrete multi-criteria problem, creating a significant burden on the decision maker. A new method of controlling the learning trajectory has been developed. The article discusses problem statement and solution of determining student’s optimal individual educational trajectory as a dynamic model of learning trajectory control, which uses score assessment to construct a sequence of studied subjects. A new model of management learning trajectory is based on dynamic models for tracking the reference trajectory. The task can be converted to an equivalent model of linear programming, for which a reliable solution

  18. Impact of different individual GNSS receiver antenna calibration models on geodetic positioning

    Science.gov (United States)

    Baire, Q.; Pottiaux, E.; Bruyninx, C.; Defraigne, P.; Aerts, W.; Legrand, J.; Bergeot, N.; Chevalier, J. M.

    2012-04-01

    Since April 2011, the igs08.atx antenna calibration model is used in the routine IGS (International GNSS Service) data analysis. The model includes mean robot calibrations to correct for the offset and phase center variations of the GNSS receiver antennas. These so-called "type" calibrations are means of the individual calibrations available for a specific antenna/radome combination. The GNSS data analysis performed within the EUREF Permanent Network (EPN) aims at being as consistent as possible with the IGS analysis. This also applies to the receiver antenna calibrations. However, when available, individual antenna calibrations are used within the EPN analysis instead of the "type" calibration. When these individual calibrations are unavailable, then the EPN analysis falls back to (type) calibrations identical as the ones used within the IGS (igs08.atx). The aim of this study is to evaluate the significance of the offset caused by using different receiver antenna calibration models on the station position. Using the PPP (Precise Point Positioning) technique, we first investigate the differences in positioning obtained when switching between individual antenna calibrations and type calibrations. We analyze the observations of the 43 EPN stations equipped with receiver antenna individually calibrated over the period covering from 2003 to 2010 and we show that these differences can reach up to 4 mm in horizontal and 10 mm in vertical. Secondly, we study the accuracy of the individual calibrations models and we evaluate the effect of different sets of individual calibrations on the positioning. For that purpose, we use the data from 6 GNSS stations equipped with an antenna which has been individually calibrated at two calibration facilities recognized by the IGS: GEO++ and Bonn institute.

  19. Exact solution of gyration radius of individual's trajectory for a simplified human mobility model

    OpenAIRE

    Yan, Xiao-Yong; Han, Xiao-Pu; Zhou, Tao; Wang, Bing-Hong

    2010-01-01

    Gyration radius of individual's trajectory plays a key role in quantifying human mobility patterns. Of particular interests, empirical analyses suggest that the growth of gyration radius is slow versus time except the very early stage and may eventually arrive to a steady value. However, up to now, the underlying mechanism leading to such a possibly steady value has not been well understood. In this Letter, we propose a simplified human mobility model to simulate individual's daily travel wit...

  20. Anatomy of Student Models in Adaptive Learning Systems: A Systematic Literature Review of Individual Differences from 2001 to 2013

    Science.gov (United States)

    Nakic, Jelena; Granic, Andrina; Glavinic, Vlado

    2015-01-01

    This study brings an evidence-based review of user individual characteristics employed as sources of adaptation in recent adaptive learning systems. Twenty-two user individual characteristics were explored in a systematically designed search procedure, while 17 of them were identified as sources of adaptation in final selection. The content…

  1. Characteristics and Diffusion Model of the Individual Knowledge in the WeChat Mode

    Directory of Open Access Journals (Sweden)

    Zhang Lingzhi

    2017-12-01

    Full Text Available [Purpose/significance] According to the model of the individual knowledge diffusion, we conduct a behavior research and analyze the characteristics of that based on WeChat which is the most popular communication platform in China.[Method/process] By analyzing the methods of the diffusion on WeChat, we analyzed the characteristics of the individual knowledge diffusion. [Result/conclusion]The characteristics of the individual knowledge diffusion include real-time, short-term, speciality, friendship and transmission.

  2. Competition of Dynamic Self-Confidence and Inhomogeneous Individual Influence in Voter Models

    Directory of Open Access Journals (Sweden)

    Fei Xiong

    2013-12-01

    Full Text Available In social systems, agents often have different ability to persuade neighbors to adopt their opinions. In this paper, we aim to investigate how the location and heterogeneity of influencers in social networks can improve convergence. We propose a voter model with dynamic self-conviction and heterogeneous individual influence which is related to the underlying network topology. An agent may keep its current opinion according to personal conviction, or otherwise, it may preferentially choose the opinion of the neighbor that has a great influence. Individual conviction evolves during the dynamic process, and can be strengthened by social recognition. Simulations indicate our model has three nontrivial results. First, the conservation of average magnetization in the voter model is broken under the effect of individual conviction and influence, and the system evolves to an ordered state in which one opinion is dominant, but total consensus is prevented by extremists. Furthermore, individual influence has a subtle action on opinion evolution. The heterogeneity of individual influence accelerates the relaxation process, but, with the action of dynamic conviction, more heterogeneous influence does not mean the average magnetization will be more ordered. In addition, when competing with agents’ conviction, more heterogeneous individual influence plays a more significant role in agents’ decisions. These results are helpful for understanding some aspects of collective phenomena that occur on online social media.

  3. A multiprocessor computer simulation model employing a feedback scheduler/allocator for memory space and bandwidth matching and TMR processing

    Science.gov (United States)

    Bradley, D. B.; Irwin, J. D.

    1974-01-01

    A computer simulation model for a multiprocessor computer is developed that is useful for studying the problem of matching multiprocessor's memory space, memory bandwidth and numbers and speeds of processors with aggregate job set characteristics. The model assumes an input work load of a set of recurrent jobs. The model includes a feedback scheduler/allocator which attempts to improve system performance through higher memory bandwidth utilization by matching individual job requirements for space and bandwidth with space availability and estimates of bandwidth availability at the times of memory allocation. The simulation model includes provisions for specifying precedence relations among the jobs in a job set, and provisions for specifying precedence execution of TMR (Triple Modular Redundant and SIMPLEX (non redundant) jobs.

  4. Development of RBMK-1500 Relap5 model by employing main circulation pump trip events at Ignalina NPP date base

    International Nuclear Information System (INIS)

    Kaliatka, A.; Krivoshein, G.; Uspuras, E.

    2001-01-01

    The Ignalina Nuclear Power Plant is a twin-unit with two RBMK-1500, graphite moderated, boiling water, multichannel reactors. The state of the art code RELAP5 was originally designed for Pressurized Water Reactors. Because of unique RBMK design, the application of this code to RBMK-1500 encountered several problems. The paper deals with the development of proper Ignalina NPP RELAP5 model and investigation of MCPs trip events. A successful best estimate RELAP5 model of the Ignalina NPP has been developed. This model includes the reactor main circulation circuit, reactor control systems and plant safety systems required for transient analysis. There were few events when one MCP was inadvertently tripped at the Ignalina NPP. On May 14, 1996 one MCP at Ignalina Unit 2 was inadvertently tripped. The similar event took place on January 23, 1998. During this event, the MCP check valve failed to close, causing a re-circulation loop to develop by means of a reversed flow through the tripped pump. On July 31, 2000 three MCPs at Ignalina Unit 2 were tripped one after another, due to inadvertent activation of fire protection system. Calculations performed with Ignalina NPP RELAP5 model agree favorably with the plant data. The developed RELAP5 model is proper and may be employed for the plant analysis. (author)

  5. Employing Model-Based Reasoning in Interdisciplinary Research Teams: Evidence-Based Practices for Integrating Knowledge Across Systems

    Science.gov (United States)

    Pennington, D. D.; Vincent, S.

    2017-12-01

    The NSF-funded project "Employing Model-Based Reasoning in Socio-Environmental Synthesis (EMBeRS)" has developed a generic model for exchanging knowledge across disciplines that is based on findings from the cognitive, learning, social, and organizational sciences addressing teamwork in complex problem solving situations. Two ten-day summer workshops for PhD students from large, NSF-funded interdisciplinary projects working on a variety of water issues were conducted in 2016 and 2017, testing the model by collecting a variety of data, including surveys, interviews, audio/video recordings, material artifacts and documents, and photographs. This presentation will introduce the EMBeRS model, the design of workshop activities based on the model, and results from surveys and interviews with the participating students. Findings suggest that this approach is very effective for developing a shared, integrated research vision across disciplines, compared with activities typically provided by most large research projects, and that students believe the skills developed in the EMBeRS workshops are unique and highly desireable.

  6. A reciprocal model of face recognition and autistic traits: evidence from an individual differences perspective.

    Directory of Open Access Journals (Sweden)

    Drew W R Halliday

    Full Text Available Although not a core symptom of the disorder, individuals with autism often exhibit selective impairments in their face processing abilities. Importantly, the reciprocal connection between autistic traits and face perception has rarely been examined within the typically developing population. In this study, university participants from the social sciences, physical sciences, and humanities completed a battery of measures that assessed face, object and emotion recognition abilities, general perceptual-cognitive style, and sub-clinical autistic traits (the Autism Quotient (AQ. We employed separate hierarchical multiple regression analyses to evaluate which factors could predict face recognition scores and AQ scores. Gender, object recognition performance, and AQ scores predicted face recognition behaviour. Specifically, males, individuals with more autistic traits, and those with lower object recognition scores performed more poorly on the face recognition test. Conversely, university major, gender and face recognition performance reliably predicted AQ scores. Science majors, males, and individuals with poor face recognition skills showed more autistic-like traits. These results suggest that the broader autism phenotype is associated with lower face recognition abilities, even among typically developing individuals.

  7. A reciprocal model of face recognition and autistic traits: evidence from an individual differences perspective.

    Science.gov (United States)

    Halliday, Drew W R; MacDonald, Stuart W S; Scherf, K Suzanne; Sherf, Suzanne K; Tanaka, James W

    2014-01-01

    Although not a core symptom of the disorder, individuals with autism often exhibit selective impairments in their face processing abilities. Importantly, the reciprocal connection between autistic traits and face perception has rarely been examined within the typically developing population. In this study, university participants from the social sciences, physical sciences, and humanities completed a battery of measures that assessed face, object and emotion recognition abilities, general perceptual-cognitive style, and sub-clinical autistic traits (the Autism Quotient (AQ)). We employed separate hierarchical multiple regression analyses to evaluate which factors could predict face recognition scores and AQ scores. Gender, object recognition performance, and AQ scores predicted face recognition behaviour. Specifically, males, individuals with more autistic traits, and those with lower object recognition scores performed more poorly on the face recognition test. Conversely, university major, gender and face recognition performance reliably predicted AQ scores. Science majors, males, and individuals with poor face recognition skills showed more autistic-like traits. These results suggest that the broader autism phenotype is associated with lower face recognition abilities, even among typically developing individuals.

  8. A Review of Models for Dose Assessment Employed by SKB in the Renewed Safety Assessment for SFR 1

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, George [Imperial College of Science Technology and Medicine (United Kingdom)

    2002-09-01

    This document provides a critical review, on behalf of SSI, of the models employed by the Swedish Nuclear Fuel and Waste Management Co (SKB) for dose assessment in the renewed safety assessment for the final repository for radioactive operational waste (SFR 1) in Forsmark, Sweden. The main objective of the review is to examine the models used by SKB for radiological dose assessment in a series of evolving biotopes in the vicinity of the Forsmark repository within a time frame beginning in 3000 AD and extending beyond 7500 AD. Five biosphere models (for coasts, lakes, agriculture, mires and wells) are described in Report TR-01-04. The principal consideration of the review is to determine whether these models are fit for the purpose of dose evaluation over the time frames involved and in the evolving sequence of biotopes specified. As well as providing general observations and comments on the modelling approach taken, six specific questions are addressed, as follows. Are the assumptions underlying the models justifiable? Are all reasonably foreseeable environmental processes considered? Has parameter uncertainty been sufficiently and reasonably addressed? Have sufficient models been used to address all reasonably foreseeable biotopes? Are the transitions between biotopes modelled adequately (specifically, are initial conditions for developing biotopes adequately specified by calculations for subsiding biotopes)? Have all critical radionuclides been identified? It is concluded that, in general, the assumptions underlying most of the models are justifiable. The exceptions are a) the rather simplistic approach taken in the Coastal Model and b) the lack of consideration of wild foods and age-dependence when calculating exposures of humans to radionuclides via dietary pathways. Most foreseeable processes appear to have been accounted for within the constraints of the models used, although it is recommended that attention be paid to future climate states when considering

  9. An individual-based probabilistic model for simulating fisheries population dynamics

    Directory of Open Access Journals (Sweden)

    Jie Cao

    2016-12-01

    Full Text Available The purpose of stock assessment is to support managers to provide intelligent decisions regarding removal from fish populations. Errors in assessment models may have devastating impacts on the population fitness and negative impacts on the economy of the resource users. Thus, accuracte estimations of population size, growth rates are critical for success. Evaluating and testing the behavior and performance of stock assessment models and assessing the consequences of model mis-specification and the impact of management strategies requires an operating model that accurately describe the dynamics of the target species, and can resolve spatial and seasonal changes. In addition, the most thorough evaluations of assessment models use an operating model that takes a different form than the assessment model. This paper presents an individual-based probabilistic model used to simulate the complex dynamics of populations and their associated fisheries. Various components of population dynamics are expressed as random Bernoulli trials in the model and detailed life and fishery histories of each individual are tracked over their life span. The simulation model is designed to be flexible so it can be used for different species and fisheries. It can simulate mixing among multiple stocks and link stock-recruit relationships to environmental factors. Furthermore, the model allows for flexibility in sub-models (e.g., growth and recruitment and model assumptions (e.g., age- or size-dependent selectivity. This model enables the user to conduct various simulation studies, including testing the performance of assessment models under different assumptions, assessing the impacts of model mis-specification and evaluating management strategies.

  10. Employer Branding

    DEFF Research Database (Denmark)

    Frimann, Søren; Mønsted, Bolette Rye

    2012-01-01

    Employer branding er både for den private og den offentlige sektor blevet en måde, de kan imødekomme ændrede arbejdsmarkedsvilkår og organisatoriske udfordringer i en postmoderne og globaliseret verden. Den aktuelle finanskrise har skabt nye udfordringer for organisationer i deres bestræbelser på...... at tiltrække- og fastholde attraktive medarbejdere. Men hvilken betydning har det, når Grundfos siger ”Mennesket er i fokus”, og hvad siger ”mangfoldighed” om Københavns Kommune som arbejdsplads i relation til employer branding? Er der egentlig sammenhæng mellem tankerne bag employer branding og de eksternt...... kommunikerede employer brandprodukter. Eller bliver det unikke ved arbejdspladserne ersattet af buzzwords uden substans og inddragelse af ansatte og interessenter? Artiklen har til formål at vurdere disse spørgsmål på baggrund af analyser af to cases med employer branding....

  11. Can plasticity make spatial structure irrelevant in individual-tree models?

    Directory of Open Access Journals (Sweden)

    Oscar García

    2014-08-01

    Full Text Available Background Distance-dependent individual-tree models have commonly been found to add little predictive power to that of distance-independent ones. One possible reason is plasticity, the ability of trees to lean and to alter crown and root development to better occupy available growing space. Being able to redeploy foliage (and roots into canopy gaps and less contested areas can diminish the importance of stem ground locations. Methods Plasticity was simulated for 3 intensively measured forest stands, to see to what extent and under what conditions the allocation of resources (e.g., light to the individual trees depended on their ground coordinates. The data came from 50 × 60 m stem-mapped plots in natural monospecific stands of jack pine, trembling aspen and black spruce from central Canada. Explicit perfect-plasticity equations were derived for tessellation-type models. Results Qualitatively similar simulation results were obtained under a variety of modelling assumptions. The effects of plasticity varied somewhat with stand uniformity and with assumed plasticity limits and other factors. Stand-level implications for canopy depth, distribution modelling and total productivity were examined. Conclusions Generally, under what seem like conservative maximum plasticity constraints, spatial structure accounted for less than 10% of the variance in resource allocation. The perfect-plasticity equations approximated well the simulation results from tessellation models, but not those from models with less extreme competition asymmetry. Whole-stand perfect plasticity approximations seem an attractive alternative to individual-tree models.

  12. Modelling Diverse Soil Attributes with Visible to Longwave Infrared Spectroscopy Using PLSR Employed by an Automatic Modelling Engine

    Directory of Open Access Journals (Sweden)

    Veronika Kopačková

    2017-02-01

    Full Text Available The study tested a data mining engine (PARACUDA® to predict various soil attributes (BC, CEC, BS, pH, Corg, Pb, Hg, As, Zn and Cu using reflectance data acquired for both optical and thermal infrared regions. The engine was designed to utilize large data in parallel and automatic processing to build and process hundreds of diverse models in a unified manner while avoiding bias and deviations caused by the operator(s. The system is able to systematically assess the effect of diverse preprocessing techniques; additionally, it analyses other parameters, such as different spectral resolutions and spectral coverages that affect soil properties. Accordingly, the system was used to extract models across both optical and thermal infrared spectral regions, which holds significant chromophores. In total, 2880 models were evaluated where each model was generated with a different preprocessing scheme of the input spectral data. The models were assessed using statistical parameters such as coefficient of determination (R2, square error of prediction (SEP, relative percentage difference (RPD and by physical explanation (spectral assignments. It was found that the smoothing procedure is the most beneficial preprocessing stage, especially when combined with spectral derivation (1st or 2nd derivatives. Automatically and without the need of an operator, the data mining engine enabled the best prediction models to be found from all the combinations tested. Furthermore, the data mining approach used in this study and its processing scheme proved to be efficient tools for getting a better understanding of the geochemical properties of the samples studied (e.g., mineral associations.

  13. Beyond modeling abstractions: Learning nouns over developmental time in atypical populations and individuals

    Directory of Open Access Journals (Sweden)

    Clare eSims

    2013-11-01

    Full Text Available Connectionist models that capture developmental change over time have much to offer in the field of language development research. Several models in the literature have made good contact with developmental data, effectively captured behavioral tasks, and accurately represented linguistic input available to young children. However, fewer models of language development have truly captured the process of developmental change over time. In this review paper, we discuss several prominent connectionist models of early word learning, focusing on semantic development, as well as our recent work modeling the emergence of word learning biases in different populations. We also discuss the potential of these kinds of models to capture children’s language development at the individual level. We argue that a modeling approach that truly captures change over time has the potential to inform theory, guide research, and lead to innovations in early language intervention.

  14. Validation of individual and aggregate global flood hazard models for two major floods in Africa.

    Science.gov (United States)

    Trigg, M.; Bernhofen, M.; Whyman, C.

    2017-12-01

    A recent intercomparison of global flood hazard models undertaken by the Global Flood Partnership shows that there is an urgent requirement to undertake more validation of the models against flood observations. As part of the intercomparison, the aggregated model dataset resulting from the project was provided as open access data. We compare the individual and aggregated flood extent output from the six global models and test these against two major floods in the African Continent within the last decade, namely severe flooding on the Niger River in Nigeria in 2012, and on the Zambezi River in Mozambique in 2007. We test if aggregating different number and combination of models increases model fit to the observations compared with the individual model outputs. We present results that illustrate some of the challenges of comparing imperfect models with imperfect observations and also that of defining the probability of a real event in order to test standard model output probabilities. Finally, we propose a collective set of open access validation flood events, with associated observational data and descriptions that provide a standard set of tests across different climates and hydraulic conditions.

  15. Predictive Models of Alcohol Use Based on Attitudes and Individual Values

    Science.gov (United States)

    Del Castillo Rodríguez, José A. García; López-Sánchez, Carmen; Soler, M. Carmen Quiles; Del Castillo-López, Álvaro García; Pertusa, Mónica Gázquez; Campos, Juan Carlos Marzo; Inglés, Cándido J.

    2013-01-01

    Two predictive models are developed in this article: the first is designed to predict people' attitudes to alcoholic drinks, while the second sets out to predict the use of alcohol in relation to selected individual values. University students (N = 1,500) were recruited through stratified sampling based on sex and academic discipline. The…

  16. Using ROC curves to compare neural networks and logistic regression for modeling individual noncatastrophic tree mortality

    Science.gov (United States)

    Susan L. King

    2003-01-01

    The performance of two classifiers, logistic regression and neural networks, are compared for modeling noncatastrophic individual tree mortality for 21 species of trees in West Virginia. The output of the classifier is usually a continuous number between 0 and 1. A threshold is selected between 0 and 1 and all of the trees below the threshold are classified as...

  17. Modelling collective foraging by means of individual behaviour rules in honey-bees

    NARCIS (Netherlands)

    Vries, Han de; Biesmeijer, J.C.

    1998-01-01

    An individual-oriented model is constructed which simulates the collective foraging behaviour of a colony of honey-bees, Apis mellifera. Each bee follows the same set of behavioural rules. Each rule consists of a set of conditions followed by the behavioural act to be performed if the

  18. Age Differences within Secular IQ Trends: An Individual Growth Modeling Approach

    Science.gov (United States)

    Kanaya, Tomoe; Ceci, Stephen J.; Scullin, Matthew H.

    2005-01-01

    Age differences within the yo-yo trend in IQ, caused when aging norms that produce inflated scores are replaced with new norms, were examined using longitudinal WISC, WISC-R and WISC-III records of students tested for special education services from 10 school districts. Descriptive and individual growth modeling analyses revealed that while the…

  19. Continuous time modelling with individually varying time intervals for oscillating and non-oscillating processes.

    Science.gov (United States)

    Voelkle, Manuel C; Oud, Johan H L

    2013-02-01

    When designing longitudinal studies, researchers often aim at equal intervals. In practice, however, this goal is hardly ever met, with different time intervals between assessment waves and different time intervals between individuals being more the rule than the exception. One of the reasons for the introduction of continuous time models by means of structural equation modelling has been to deal with irregularly spaced assessment waves (e.g., Oud & Delsing, 2010). In the present paper we extend the approach to individually varying time intervals for oscillating and non-oscillating processes. In addition, we show not only that equal intervals are unnecessary but also that it can be advantageous to use unequal sampling intervals, in particular when the sampling rate is low. Two examples are provided to support our arguments. In the first example we compare a continuous time model of a bivariate coupled process with varying time intervals to a standard discrete time model to illustrate the importance of accounting for the exact time intervals. In the second example the effect of different sampling intervals on estimating a damped linear oscillator is investigated by means of a Monte Carlo simulation. We conclude that it is important to account for individually varying time intervals, and encourage researchers to conceive of longitudinal studies with different time intervals within and between individuals as an opportunity rather than a problem. © 2012 The British Psychological Society.

  20. Generic linear mixed-effects individual-tree biomass models for ...

    African Journals Online (AJOL)

    Quantification of forest biomass is important for practical forestry and for scientific purposes. It is fundamental to develop generic individual-tree biomass models suitable for large-scale forest biomass estimation. However, compatibility of forest biomass estimates at different scales may become a problem. We developed ...

  1. Using a Structural Equation Model to Examine Factors Affecting Married Individuals' Sexual Embarrassment

    Science.gov (United States)

    Celik, Eyup; Arici, Neslihan

    2014-01-01

    This study aimed to predict the effects of levels of sexual awareness, sexual courage, and sexual self-disclosure on sexual embarrassment. Data was collected from 336 married individuals, who have students in the Sultangazi District of Istanbul. According to the structural equation model (SEM), sexual self-disclosure, directly, and sexual courage…

  2. Selection through Individualized Review: A Report on Phase IV of the Admissions Models Project

    Science.gov (United States)

    Rigol, Gretchen W.

    2004-01-01

    This is the fourth monograph in the admissions models series. Based on discussions at a June 2004 conference and conversations with numerous admissions experts, this publication describes different approaches to individualized review and covers topics such as standardizing elements of the application, reader training and guidelines, consistency…

  3. An Integrated, Multidimensional Treatment Model for Individuals Living with HIV, Mental Illness, and Substance Abuse

    Science.gov (United States)

    Bouis, Stephanie; Reif, Susan; Whetten, Kathryn; Scovil, Janet; Murray, Andrea; Swartz, Marvin

    2007-01-01

    The challenge of providing effective treatment services for the growing population of HIV-positive individuals who are also dually diagnosed with substance use and mental disorders has only recently been recognized as an important public health concern affecting both HIV treatment and prevention. This article describes a treatment model that was…

  4. A global model of stress in parents of individuals with autism spectrum disorders (ASD

    Directory of Open Access Journals (Sweden)

    Pilar Pozo

    2014-01-01

    Full Text Available This research sought to analyse stress among mothers and fathers of individuals with autism spectrum disorders (ASD to determine the relevant variables for its explanation and the possible gender differences. To examine parents' stress, we propose a multidimensional model based on the Double ABCX theoretical model. We argue that the result of stress depends on the following four interrelated factors: the characteristics of the individual with ASD (the severity of the disorder and behaviour problems, the social supports, the parents' perception of the situation (evaluated by sense of coherence and the coping strategies. Fiftynine sets of parents (59 mothers and 59 fathers of individuals diagnosed with ASD participated in the study. The data were analysed using a path analysis through the LISREL 8.80 program. We obtained two empirical models of stress: one model for mothers and one for fathers. In both models, the severity of the disorder and the behaviour problems had a direct and positive effect on stress. The sense of coherence (SOC and active avoidance coping strategies had a mediating role in models. Social support was relevant only for mothers. Finally, the results offer some guidelines for professionals working with families.

  5. Adjudicating between face-coding models with individual-face fMRI responses.

    Directory of Open Access Journals (Sweden)

    Johan D Carlin

    2017-07-01

    Full Text Available The perceptual representation of individual faces is often explained with reference to a norm-based face space. In such spaces, individuals are encoded as vectors where identity is primarily conveyed by direction and distinctiveness by eccentricity. Here we measured human fMRI responses and psychophysical similarity judgments of individual face exemplars, which were generated as realistic 3D animations using a computer-graphics model. We developed and evaluated multiple neurobiologically plausible computational models, each of which predicts a representational distance matrix and a regional-mean activation profile for 24 face stimuli. In the fusiform face area, a face-space coding model with sigmoidal ramp tuning provided a better account of the data than one based on exemplar tuning. However, an image-processing model with weighted banks of Gabor filters performed similarly. Accounting for the data required the inclusion of a measurement-level population averaging mechanism that approximates how fMRI voxels locally average distinct neuronal tunings. Our study demonstrates the importance of comparing multiple models and of modeling the measurement process in computational neuroimaging.

  6. An individual-based modelling approach to estimate landscape connectivity for bighorn sheep (Ovis canadensis

    Directory of Open Access Journals (Sweden)

    Corrie H. Allen

    2016-05-01

    Full Text Available Background. Preserving connectivity, or the ability of a landscape to support species movement, is among the most commonly recommended strategies to reduce the negative effects of climate change and human land use development on species. Connectivity analyses have traditionally used a corridor-based approach and rely heavily on least cost path modeling and circuit theory to delineate corridors. Individual-based models are gaining popularity as a potentially more ecologically realistic method of estimating landscape connectivity. However, this remains a relatively unexplored approach. We sought to explore the utility of a simple, individual-based model as a land-use management support tool in identifying and implementing landscape connectivity. Methods. We created an individual-based model of bighorn sheep (Ovis canadensis that simulates a bighorn sheep traversing a landscape by following simple movement rules. The model was calibrated for bighorn sheep in the Okanagan Valley, British Columbia, Canada, a region containing isolated herds that are vital to conservation of the species in its northern range. Simulations were run to determine baseline connectivity between subpopulations in the study area. We then applied the model to explore two land management scenarios on simulated connectivity: restoring natural fire regimes and identifying appropriate sites for interventions that would increase road permeability for bighorn sheep. Results. This model suggests there are no continuous areas of good habitat between current subpopulations of sheep in the study area; however, a series of stepping-stones or circuitous routes could facilitate movement between subpopulations and into currently unoccupied, yet suitable, bighorn habitat. Restoring natural fire regimes or mimicking fire with prescribed burns and tree removal could considerably increase bighorn connectivity in this area. Moreover, several key road crossing sites that could benefit from

  7. Automated MRI segmentation for individualized modeling of current flow in the human head

    Science.gov (United States)

    Huang, Yu; Dmochowski, Jacek P.; Su, Yuzhuo; Datta, Abhishek; Rorden, Christopher; Parra, Lucas C.

    2013-12-01

    Objective. High-definition transcranial direct current stimulation (HD-tDCS) and high-density electroencephalography require accurate models of current flow for precise targeting and current source reconstruction. At a minimum, such modeling must capture the idiosyncratic anatomy of the brain, cerebrospinal fluid (CSF) and skull for each individual subject. Currently, the process to build such high-resolution individualized models from structural magnetic resonance images requires labor-intensive manual segmentation, even when utilizing available automated segmentation tools. Also, accurate placement of many high-density electrodes on an individual scalp is a tedious procedure. The goal was to develop fully automated techniques to reduce the manual effort in such a modeling process. Approach. A fully automated segmentation technique based on Statical Parametric Mapping 8, including an improved tissue probability map and an automated correction routine for segmentation errors, was developed, along with an automated electrode placement tool for high-density arrays. The performance of these automated routines was evaluated against results from manual segmentation on four healthy subjects and seven stroke patients. The criteria include segmentation accuracy, the difference of current flow distributions in resulting HD-tDCS models and the optimized current flow intensities on cortical targets.Main results. The segmentation tool can segment out not just the brain but also provide accurate results for CSF, skull and other soft tissues with a field of view extending to the neck. Compared to manual results, automated segmentation deviates by only 7% and 18% for normal and stroke subjects, respectively. The predicted electric fields in the brain deviate by 12% and 29% respectively, which is well within the variability observed for various modeling choices. Finally, optimized current flow intensities on cortical targets do not differ significantly.Significance. Fully

  8. From Genes to Ecosystems in Microbiology: Modeling Approaches and the Importance of Individuality

    Directory of Open Access Journals (Sweden)

    Jan-Ulrich Kreft

    2017-11-01

    Full Text Available Models are important tools in microbial ecology. They can be used to advance understanding by helping to interpret observations and test hypotheses, and to predict the effects of ecosystem management actions or a different climate. Over the past decades, biological knowledge and ecosystem observations have advanced to the molecular and in particular gene level. However, microbial ecology models have changed less and a current challenge is to make them utilize the knowledge and observations at the genetic level. We review published models that explicitly consider genes and make predictions at the population or ecosystem level. The models can be grouped into three general approaches, i.e., metabolic flux, gene-centric and agent-based. We describe and contrast these approaches by applying them to a hypothetical ecosystem and discuss their strengths and weaknesses. An important distinguishing feature is how variation between individual cells (individuality is handled. In microbial ecosystems, individual heterogeneity is generated by a number of mechanisms including stochastic interactions of molecules (e.g., gene expression, stochastic and deterministic cell division asymmetry, small-scale environmental heterogeneity, and differential transport in a heterogeneous environment. This heterogeneity can then be amplified and transferred to other cell properties by several mechanisms, including nutrient uptake, metabolism and growth, cell cycle asynchronicity and the effects of age and damage. For example, stochastic gene expression may lead to heterogeneity in nutrient uptake enzyme levels, which in turn results in heterogeneity in intracellular nutrient levels. Individuality can have important ecological consequences, including division of labor, bet hedging, aging and sub-optimality. Understanding the importance of individuality and the mechanism(s underlying it for the specific microbial system and question investigated is essential for selecting the

  9. Maine's Employability Skills Program

    Science.gov (United States)

    McMahon, John M.; Wolffe, Karen E.; Wolfe, Judy; Brooker, Carrie

    2013-01-01

    This Practice Report describes the development and implementation of the "Maine Employability Skills Program," a model employment program developed by the Maine Division for the Blind and Visually Impaired (DBVI). The program was designed to support the efforts of the chronically unemployed or underemployed. These consumers were either…

  10. Who will have Sustainable Employment After a Back Injury? The Development of a Clinical Prediction Model in a Cohort of Injured Workers.

    Science.gov (United States)

    Shearer, Heather M; Côté, Pierre; Boyle, Eleanor; Hayden, Jill A; Frank, John; Johnson, William G

    2017-09-01

    Purpose Our objective was to develop a clinical prediction model to identify workers with sustainable employment following an episode of work-related low back pain (LBP). Methods We used data from a cohort study of injured workers with incident LBP claims in the USA to predict employment patterns 1 and 6 months following a workers' compensation claim. We developed three sequential models to determine the contribution of three domains of variables: (1) basic demographic/clinical variables; (2) health-related variables; and (3) work-related factors. Multivariable logistic regression was used to develop the predictive models. We constructed receiver operator curves and used the c-index to measure predictive accuracy. Results Seventy-nine percent and 77 % of workers had sustainable employment at 1 and 6 months, respectively. Sustainable employment at 1 month was predicted by initial back pain intensity, mental health-related quality of life, claim litigation and employer type (c-index = 0.77). At 6 months, sustainable employment was predicted by physical and mental health-related quality of life, claim litigation and employer type (c-index = 0.77). Adding health-related and work-related variables to models improved predictive accuracy by 8.5 and 10 % at 1 and 6 months respectively. Conclusion We developed clinically-relevant models to predict sustainable employment in injured workers who made a workers' compensation claim for LBP. Inquiring about back pain intensity, physical and mental health-related quality of life, claim litigation and employer type may be beneficial in developing programs of care. Our models need to be validated in other populations.

  11. Grasping Kinematics from the Perspective of the Individual Digits: A Modelling Study

    Science.gov (United States)

    Verheij, Rebekka; Brenner, Eli; Smeets, Jeroen B. J.

    2012-01-01

    Grasping is a prototype of human motor coordination. Nevertheless, it is not known what determines the typical movement patterns of grasping. One way to approach this issue is by building models. We developed a model based on the movements of the individual digits. In our model the following objectives were taken into account for each digit: move smoothly to the preselected goal position on the object without hitting other surfaces, arrive at about the same time as the other digit and never move too far from the other digit. These objectives were implemented by regarding the tips of the digits as point masses with a spring between them, each attracted to its goal position and repelled from objects' surfaces. Their movements were damped. Using a single set of parameters, our model can reproduce a wider variety of experimental findings than any previous model of grasping. Apart from reproducing known effects (even the angles under which digits approach trapezoidal objects' surfaces, which no other model can explain), our model predicted that the increase in maximum grip aperture with object size should be greater for blocks than for cylinders. A survey of the literature shows that this is indeed how humans behave. The model can also adequately predict how single digit pointing movements are made. This supports the idea that grasping kinematics follow from the movements of the individual digits. PMID:22412997

  12. Contextual and individual determinants of periodontal disease: Multilevel analysis based on Andersen's model.

    Science.gov (United States)

    Valente, Maria I B; Vettore, Mario V

    2017-11-17

    To investigate the relationship of contextual and individual factors with periodontal disease in dentate adults and older people using the Andersen's behavioural model. Secondary individual data from 6011 adults and 2369 older people from the Brazilian Oral Health Survey (2010) were combined with contextual data for 27 cities. Attachment loss (AL) categories for each sextant were coded and summed to obtain the periodontal disease measure. The association of predisposing, enabling and need characteristics at city and individual level with periodontal disease was assessed using an adapted version of the Andersen's behavioural model. Multilevel Poisson regression was used to estimate rate ratios (RR) and 95% CIs. Periodontal disease was associated with contextual predisposing (RR 0.93; 95% CI = 0.87-0.99) and enabling factors (RR 0.99; 95% CI = 0.98-0.99) in adults. Contextual predisposing was also associated with periodontal disease in older people (RR 0.82; 95% CI = 0.73-0.92). Individual predisposing (age, sex and schooling) and need characteristics (perceived treatment need) were common predictors of periodontal disease in adults and older people. Periodontal disease was also associated with behaviours in the latter age group. Contextual predisposing factors and individual characteristics influenced periodontal disease experience in adults and older people. Contextual enabling factors were also meaningful determinants of periodontal disease in the former age group. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Crowd of individuals walking in opposite directions. A toy model to study the segregation of the group into lanes of individuals moving in the same direction

    Science.gov (United States)

    Goldsztein, Guillermo H.

    2017-08-01

    Consider a corridor, street or bridge crowded with pedestrians walking in both directions. The individuals do not walk in a completely straight line. They adjust their path to avoid colliding with incoming pedestrians. As a result of these adjustments, the whole group sometimes end up split into lanes of individuals moving in the same direction. While this formation of lanes facilitates the flow and benefits the whole group, it is believed that results from the actions of the individuals acting only on their behalf, without considering others. This phenomenon is an example of self-organization. We analyze a simple model. We assume that individuals move around a two-lane circular track. All of them at the same speed. Half of them in one direction and the rest in the opposite direction. Each time two individuals collide, one of them moves to the other lane. The individual changing lanes is selected randomly. The system self-organizes. Eventually each lane is occupied with individuals moving in only one direction. We show that the time required for the system to self-organize is bounded by a linear function on the number of individuals. This toy model provides an example where global self-organization occurs even though each member of the group acts without considering the rest.

  14. An individual-based growth and competition model for coastal redwood forest restoration

    Science.gov (United States)

    van Mantgem, Phillip J.; Das, Adrian J.

    2014-01-01

    Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitive environments in coastal redwood forests. We created a spatially explicit individual-based model of tree competition and growth parameterized using surveys of upland redwood forests at Redwood National Park, California. We modeled competition for overstory trees (stems ≥ 20 cm stem diameter at breast height, 1.37 m (dbh)) as growth reductions arising from sizes, distances, and species identity of competitor trees. Our model explained up to half of the variation in individual tree growth, suggesting that neighborhood crowding is an important determinant of growth in this forest type. We used our model to simulate the effects of novel thinning prescriptions (e.g., 40% stand basal area removal) for redwood forest restoration, concluding that these treatments could lead to substantial growth releases, particularly for S. sempervirens. The results of this study, along with continued improvements to our model, will help to determine spacing and species composition that best encourage growth.

  15. A place-based model of local activity spaces: individual place exposure and characteristics

    Science.gov (United States)

    Hasanzadeh, Kamyar; Laatikainen, Tiina; Kyttä, Marketta

    2018-01-01

    Researchers for long have hypothesized relationships between mobility, urban context, and health. Despite the ample amount of discussions, the empirical findings corroborating such associations remain to be marginal in the literature. It is growingly believed that the weakness of the observed associations can be largely explained by the common misspecification of the geographical context. Researchers coming from different fields have developed a wide range of methods for estimating the extents of these geographical contexts. In this article, we argue that no single approach yet has sufficiently been capable of capturing the complexity of human mobility patterns. Subsequently, we discuss that reaching a better understanding of individual activity spaces can be possible through a spatially sensitive estimation of place exposure. Following this discussion, we take an integrative person and place-based approach to create an individualized residential exposure model (IREM) to estimate the local activity spaces (LAS) of the individuals. This model is created using data collected through public participation GIS. Following a brief comparison of IREM with other commonly used LAS models, the article continues by presenting an empirical study of aging citizens in Helsinki area to demonstrate the usability of the proposed framework. In this study, we identify the main dimensions of LASs and seek their associations with socio-demographic characteristics of individuals and their location in the region. The promising results from comparisons and the interesting findings from the empirical part suggest both a methodological and conceptual improvement in capturing the complexity of local activity spaces.

  16. An individual-based model simulating goat response variability and long-term herd performance.

    Science.gov (United States)

    Puillet, L; Martin, O; Sauvant, D; Tichit, M

    2010-12-01

    Finding ways of increasing the efficiency of production systems is a key issue of sustainability. System efficiency is based on long-term individual efficiency, which is highly variable and management driven. To study the effects of management on herd and individual efficiency, we developed the model simulation of goat herd management (SIGHMA). This dynamic model is individual-based and represents the interactions between technical operations (relative to replacement, reproduction and feeding) and individual biological processes (performance dynamics based on energy partitioning and production potential). It simulates outputs at both herd and goat levels over 20 years. A farmer's production project (i.e. a targeted milk production pattern) is represented by configuring the herd into female groups reflecting the organisation of kidding periods. Each group is managed by discrete events applying decision rules to simulate the carrying out of technical operations. The animal level is represented by a set of individual goat models. Each model simulates a goat's biological dynamics through its productive life. It integrates the variability of biological responses driven by genetic scaling parameters (milk production potential and mature body weight), by the regulations of energy partitioning among physiological functions and by responses to diet energy defined by the feeding strategy. A sensitivity analysis shows that herd efficiency was mainly affected by feeding management and to a lesser extent by the herd production potential. The same effects were observed on herd milk feed costs with an even lower difference between production potential and feeding management. SIGHMA was used in a virtual experiment to observe the effects of feeding strategies on herd and individual performances. We found that overfeeding led to a herd production increase and a feed cost decrease. However, this apparent increase in efficiency at the herd level (as feed cost decreased) was related

  17. A standard protocol for describing individual-based and agent-based models

    Science.gov (United States)

    Grimm, Volker; Berger, Uta; Bastiansen, Finn; Eliassen, Sigrunn; Ginot, Vincent; Giske, Jarl; Goss-Custard, John; Grand, Tamara; Heinz, Simone K.; Huse, Geir; Huth, Andreas; Jepsen, Jane U.; Jorgensen, Christian; Mooij, Wolf M.; Muller, Birgit; Pe'er, Guy; Piou, Cyril; Railsback, Steven F.; Robbins, Andrew M.; Robbins, Martha M.; Rossmanith, Eva; Ruger, Nadja; Strand, Espen; Souissi, Sami; Stillman, Richard A.; Vabo, Rune; Visser, Ute; DeAngelis, Donald L.

    2006-01-01

    Simulation models that describe autonomous individual organisms (individual based models, IBM) or agents (agent-based models, ABM) have become a widely used tool, not only in ecology, but also in many other disciplines dealing with complex systems made up of autonomous entities. However, there is no standard protocol for describing such simulation models, which can make them difficult to understand and to duplicate. This paper presents a proposed standard protocol, ODD, for describing IBMs and ABMs, developed and tested by 28 modellers who cover a wide range of fields within ecology. This protocol consists of three blocks (Overview, Design concepts, and Details), which are subdivided into seven elements: Purpose, State variables and scales, Process overview and scheduling, Design concepts, Initialization, Input, and Submodels. We explain which aspects of a model should be described in each element, and we present an example to illustrate the protocol in use. In addition, 19 examples are available in an Online Appendix. We consider ODD as a first step for establishing a more detailed common format of the description of IBMs and ABMs. Once initiated, the protocol will hopefully evolve as it becomes used by a sufficiently large proportion of modellers.

  18. Illegal employment

    Directory of Open Access Journals (Sweden)

    Jana Mervartová

    2013-01-01

    Full Text Available Since 2007 Labour Code contains the definition of dependent work, which can be carried out only in labour-law relations. The Amendment to Labour Code from 2012 makes the definition more precise, when it stipulates essential elements of dependent work and designates the others as conditions, under which dependent work should be carried out. The Amendment to Employment Act changes the definition of illegal work. Illegal work is a performance of dependent work by natural person except for labour-law relation, or if natural person – foreigner carries out work in conflict with issued permission to employment or without this permission. Since 2012 sanctions for illegal work were increased. Labour inspection is entitled to impose sanctions, in case of foreigners it is Customs Office. For control purposes employer is obliged to have copies of documents at the workplace proving the existence of labour-law relation. Goal of controls and high fines is to limit illegal employment of citizens of Czech Republic and foreigners as well. Illegal work has unfavourable economic impact on state budget. It comes to extensive tax evasions and also to evasions within health insurance and social security. If a concluded commercial-law relation meets the attributes of dependent work, then it stands for a concealed legal relationship. Tax Office can subsequently assess an income tax to businessman. Labour-law relationship enjoys a higher legal protection than commercial-law relationship; nonetheless it is not suitable to limit liberty of contract in cases when it is not unambiguously a dependent activity.

  19. An individual reproduction model sensitive to milk yield and body condition in Holstein dairy cows.

    Science.gov (United States)

    Brun-Lafleur, L; Cutullic, E; Faverdin, P; Delaby, L; Disenhaus, C

    2013-08-01

    To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reproduction model sensitive to both MY and body condition score (BCS). A dynamic and stochastic individual reproduction model was built mainly from data of a single recent long-term experiment. This model covers the whole reproductive process and is composed of a succession of discrete stochastic events, mainly calving, ovulations, conception and embryonic loss. Each reproductive step is sensitive to MY or BCS levels or changes. The model takes into account recent evolutions of reproductive performance, particularly concerning calving-to-first ovulation interval, cyclicity (normal cycle length, prevalence of prolonged luteal phase), oestrus expression and pregnancy (conception, early and late embryonic loss). A sensitivity analysis of the model to MY and BCS at calving was performed. The simulated performance was compared with observed data from the database used to build the model and from the bibliography to validate the model. Despite comprising a whole series of reproductive steps, the model made it possible to simulate realistic global reproduction outputs. It was able to well simulate the overall reproductive performance observed in farms in terms of both success rate (recalving rate) and reproduction delays (calving interval). This model has the purpose to be integrated in herd simulation models to usefully test the impact of management strategies on herd reproductive performance, and thus on calving patterns and culling rates.

  20. PHYSICAL OBJECT-ORIENTED MODELING IN DEVELOPMENT OF INDIVIDUALIZED TEACHING AND ORGANIZATION OF MINI-RESEARCH IN MECHANICS COURSES

    Directory of Open Access Journals (Sweden)

    Alexander S. Chirtsov

    2017-03-01

    Full Text Available Subject of Research. The paper presents a relatively simple method to develop interactive computer models of physical systems without computer programming skills or automatic generation of the numerical computer code for the complex physical systems. Developed computer models are available over the Internet for educational purposes and can be edited by users in an unlimited number of possibilities. An applicability of computer simulations for the massive open individualized teaching and an organization of undergraduate research are also discussed. Method. The presented approach employs an original physical object-oriented modeling method, which is an extension of object-oriented programming ideas to tasks of developing simulations of the complex physical systems. In this framework, a computer model of the physical system is constructed as a set of interconnected computer objects simulating the system components: particles and fields. Interactions between the system components are described by self-adapting algorithms that are specified during the model initiation stage and are set according to either the classical or relativistic approach. The utilized technique requires neither a priori knowledge regarding an evolution of the physical system nor a formulation of differential equations describing the physical system. Main Results. Testing of the numerical implementation and an accuracy of the algorithms was performed with the use of benchmarks with the known analytical solutions. The developed method - a physical reality constructor - has provided an opportunity to assemble a series of computer models to demonstrate physical phenomena studied in the high school and university mechanic courses. More than 150 original interactive models were included into the collections of multi-level multimedia resources to support teaching of the mechanics. The physical reality constructor was successfully tested to serve as a test bed for the independent

  1. Biodiversity patterns from an individual-based competition model on niche and physical spaces

    International Nuclear Information System (INIS)

    Fort, H; Inchausti, P

    2012-01-01

    We formulate a microscopic (individual-based and spatially explicit) ecological model to assess whether key patterns of community structure, species-packing and the spatial distribution of species are robust to relaxing the mean-field approximation made in classical ecological models. In this model of community dynamics species compete both locally in physical space and along a niche axis and it includes just two free parameters, σ, controlling the extent of competition in niche space, and t, the simulation time. This minimalistic model (1) reproduces with considerable accuracy the dynamic sequence of relative species abundances, biodiversity indices and species–area relationships that are empirically found in censuses of trees in a well-studied tropical forest; (2) shows that the clumpy pattern of niches leading to long-lasting species coexistence obtained by classical competition models is robust to relaxing the mean-field assumption. Nevertheless species that are clumped in niche space are simultaneously spatially segregated

  2. Applying and Individual-Based Model to Simultaneously Evaluate Net Ecosystem Production and Tree Diameter Increment

    Science.gov (United States)

    Fang, F. J.

    2017-12-01

    Reconciling observations at fundamentally different scales is central in understanding the global carbon cycle. This study investigates a model-based melding of forest inventory data, remote-sensing data and micrometeorological-station data ("flux towers" estimating forest heat, CO2 and H2O fluxes). The individual tree-based model FORCCHN was used to evaluate the tree DBH increment and forest carbon fluxes. These are the first simultaneous simulations of the forest carbon budgets from flux towers and individual-tree growth estimates of forest carbon budgets using the continuous forest inventory data — under circumstances in which both predictions can be tested. Along with the global implications of such findings, this also improves the capacity for forest sustainable management and the comprehensive understanding of forest ecosystems. In forest ecology, diameter at breast height (DBH) of a tree significantly determines an individual tree's cross-sectional sapwood area, its biomass and carbon storage. Evaluation the annual DBH increment (ΔDBH) of an individual tree is central to understanding tree growth and forest ecology. Ecosystem Carbon flux is a consequence of key ecosystem processes in the forest-ecosystem carbon cycle, Gross and Net Primary Production (GPP and NPP, respectively) and Net Ecosystem Respiration (NEP). All of these closely relate with tree DBH changes and tree death. Despite advances in evaluating forest carbon fluxes with flux towers and forest inventories for individual tree ΔDBH, few current ecological models can simultaneously quantify and predict the tree ΔDBH and forest carbon flux.

  3. Modelling the effects of environmental and individual variability when measuring the costs of first reproduction

    Directory of Open Access Journals (Sweden)

    Barbraud, C.

    2004-06-01

    Full Text Available How do animals balance their investment in young against their own chances to survive and reproduce in the future? This life–history trade–off, referred to as the cost of reproduction (Williams, 1966, holds a central place in life–history theory (Roff, 1992; Stearns, 1992; McNamara & Houston, 1996. Because individuals can only acquire a limited amount of energy, reproduction and survival as well as current and future reproduction are considered as functions competing for the same resources. In this framework, individuals may optimise life–history decisions. If the reproductive effort in one year leads to a loss in future reproductive output through decreased adult survival or reduced fecundity, then the optimal effort in the current season is less than the effort that would maximize the number of offspring produced in that season (Charnov & Krebs, 1974. There are at least two kinds of factors likely to confound the measurement of the costs of reproduction in the wild. First, there could be differences in the amount of energy individuals acquire and allocate to various functions. This phenotypic heterogeneity can mask or exacerbate individual allocation patterns when trends are averaged across a population (Vaupel & Yashin, 1985; McDonald et al., 1996; Cam & Monnat, 2000. Second, there could be variations in resource availability affecting energy acquisition and allocation. Theoretical models examining the optimal phenotypic balance between reproduction and survival under variable breeding conditions have investigated the influence of environmental stochasticity on the cost of reproduction in birds (Erikstad et al., 1998; Orzack & Tuljapurkar, 2001. However, there is little empirical evidence supporting these theoretical models. Here, we present analysis of the influence of experience, but also of the differential effects of environmental and individual variation on survival and future breeding probability. We address the question of the

  4. A mechanistic spatio-temporal framework for modelling individual-to-individual transmission-With an application to the 2014-2015 West Africa Ebola outbreak.

    Directory of Open Access Journals (Sweden)

    Max S Y Lau

    2017-10-01

    Full Text Available In recent years there has been growing availability of individual-level spatio-temporal disease data, particularly due to the use of modern communicating devices with GPS tracking functionality. These detailed data have been proven useful for inferring disease transmission to a more refined level than previously. However, there remains a lack of statistically sound frameworks to model the underlying transmission dynamic in a mechanistic manner. Such a development is particularly crucial for enabling a general epidemic predictive framework at the individual level. In this paper we propose a new statistical framework for mechanistically modelling individual-to-individual disease transmission in a landscape with heterogeneous population density. Our methodology is first tested using simulated datasets, validating our inferential machinery. The methodology is subsequently applied to data that describes a regional Ebola outbreak in Western Africa (2014-2015. Our results show that the methods are able to obtain estimates of key epidemiological parameters that are broadly consistent with the literature, while revealing a significantly shorter distance of transmission. More importantly, in contrast to existing approaches, we are able to perform a more general model prediction that takes into account the susceptible population. Finally, our results show that, given reasonable scenarios, the framework can be an effective surrogate for susceptible-explicit individual models which are often computationally challenging.

  5. Repetitive model predictive approach to individual pitch control of wind turbines

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob; Odgaard, Peter Fogh

    2011-01-01

    Wind turbines are inherently exposed to nonuniform wind fields with of wind shear, tower shadow, and possible wake contributions. Asymmetrical aerodynamic rotor loads are a consequence of such periodic, repetitive wind disturbances experienced by the blades. A controller may estimate and use this....... A simulation comparison betweeen the proposed controller and an industry-standard PID controller shows better mitigation of drive-train, blade and tower loads.......Wind turbines are inherently exposed to nonuniform wind fields with of wind shear, tower shadow, and possible wake contributions. Asymmetrical aerodynamic rotor loads are a consequence of such periodic, repetitive wind disturbances experienced by the blades. A controller may estimate and use...... this peculiar disturbance pattern to better attenuate loads and regulate power by controlling the blade pitch angles individually. A novel model predictive (MPC) approach for individual pitch control of wind turbines is proposed in this paper. A repetitive wind disturbance model is incorporated into the MPC...

  6. Accounting for genetic interactions improves modeling of individual quantitative trait phenotypes in yeast.

    Science.gov (United States)

    Forsberg, Simon K G; Bloom, Joshua S; Sadhu, Meru J; Kruglyak, Leonid; Carlborg, Örjan

    2017-04-01

    Experiments in model organisms report abundant genetic interactions underlying biologically important traits, whereas quantitative genetics theory predicts, and data support, the notion that most genetic variance in populations is additive. Here we describe networks of capacitating genetic interactions that contribute to quantitative trait variation in a large yeast intercross population. The additive variance explained by individual loci in a network is highly dependent on the allele frequencies of the interacting loci. Modeling of phenotypes for multilocus genotype classes in the epistatic networks is often improved by accounting for the interactions. We discuss the implications of these results for attempts to dissect genetic architectures and to predict individual phenotypes and long-term responses to selection.

  7. Mathematical Analysis of a General Two-Patch Model of Tuberculosis Disease with Lost Sight Individuals

    Directory of Open Access Journals (Sweden)

    Abdias Laohombé

    2014-01-01

    Full Text Available A two-patch model, SEi1,…,EinIiLi,  i=1,2, is used to analyze the spread of tuberculosis, with an arbitrary number n of latently infected compartments in each patch. A fraction of infectious individuals that begun their treatment will not return to the hospital for the examination of sputum. This fact usually occurs in sub-Saharan Africa, due to many reasons. The model incorporates migrations from one patch to another. The existence and uniqueness of the associated equilibria are discussed. A Lyapunov function is used to show that when the basic reproduction ratio is less than one, the disease-free equilibrium is globally and asymptotically stable. When it is greater than one, there exists at least one endemic equilibrium. The local stability of endemic equilibria can be illustrated using numerical simulations. Numerical simulation results are provided to illustrate the theoretical results and analyze the influence of lost sight individuals.

  8. The Effect of Environmental Regulation on Employment in Resource-Based Areas of China—An Empirical Research Based on the Mediating Effect Model

    Science.gov (United States)

    Cao, Wenbin; Wang, Hui; Ying, Huihui

    2017-01-01

    While environmental pollution is becoming more and more serious, many countries are adopting policies to control pollution. At the same time, the environmental regulation will inevitably affect economic and social development, especially employment growth. The environmental regulation will not only affect the scale of employment directly, but it will also have indirect effects by stimulating upgrades in the industrial structure and in technological innovation. This paper examines the impact of environmental regulation on employment, using a mediating model based on the data from five typical resource-based provinces in China from 2000 to 2015. The estimation is performed based on the system GMM (Generalized Method of Moments) estimator. The results show that the implementation of environmental regulation in resource-based areas has both a direct effect and a mediating effect on employment. These findings provide policy implications for these resource-based areas to promote the coordinating development between the environment and employment. PMID:29257068

  9. The Effect of Environmental Regulation on Employment in Resource-Based Areas of China-An Empirical Research Based on the Mediating Effect Model.

    Science.gov (United States)

    Cao, Wenbin; Wang, Hui; Ying, Huihui

    2017-12-19

    While environmental pollution is becoming more and more serious, many countries are adopting policies to control pollution. At the same time, the environmental regulation will inevitably affect economic and social development, especially employment growth. The environmental regulation will not only affect the scale of employment directly, but it will also have indirect effects by stimulating upgrades in the industrial structure and in technological innovation. This paper examines the impact of environmental regulation on employment, using a mediating model based on the data from five typical resource-based provinces in China from 2000 to 2015. The estimation is performed based on the system GMM (Generalized Method of Moments) estimator. The results show that the implementation of environmental regulation in resource-based areas has both a direct effect and a mediating effect on employment. These findings provide policy implications for these resource-based areas to promote the coordinating development between the environment and employment.

  10. Deficiency of employability capacity

    Directory of Open Access Journals (Sweden)

    Pelse I.

    2012-10-01

    Full Text Available Young unemployed people have comprised one of the significantly largest groups of the unemployed people in Latvia in recent years. One of the reasons why young people have difficulty integrating into the labour market is the “expectation gap” that exists in the relations between employers and the new generation of workers. Employers focus on capacity-building for employability such individual factors as strength, patience, self-discipline, self-reliance, self-motivation, etc., which having a nature of habit and are developed in a long-term work socialization process, which begins even before the formal education and will continue throughout the life cycle. However, when the socialization is lost, these habits are depreciated faster than they can be restored. Currently a new generation is entering the labour market, which is missing the succession of work socialization. Factors, such as rising unemployment and poverty in the background over the past twenty years in Latvia have created a very unfavourable employability background of “personal circumstances” and “external factors”, which seriously have impaired formation of the skills and attitudes in a real work environment. The study reveals another paradox – the paradox of poverty. Common sense would want to argue that poverty can be overcome by the job. However, the real state of affairs shows that unfavourable coincidence of the individual, personal circumstances and external factors leads to deficit of employability capacity and possibility of marked social and employment deprivation.

  11. Employer-sponsored pension plans

    OpenAIRE

    Rakonjac-Antić Tatjana N.

    2004-01-01

    Apart from pension plans within social insurance, in developed pension systems there are also available to individuals schemes which may to a large extent ensure a significant part of their total pension. Among them are the following: employer-sponsored pension plans or individual pension plans. The most widely used employer-sponsored pension plan in the USA is 401(k), in which both the employer and the employee contribute to the financing of the pension. These contributions as well as the re...

  12. Development and Validation of a Prediction Model to Estimate Individual Risk of Pancreatic Cancer.

    Science.gov (United States)

    Yu, Ami; Woo, Sang Myung; Joo, Jungnam; Yang, Hye-Ryung; Lee, Woo Jin; Park, Sang-Jae; Nam, Byung-Ho

    2016-01-01

    There is no reliable screening tool to identify people with high risk of developing pancreatic cancer even though pancreatic cancer represents the fifth-leading cause of cancer-related death in Korea. The goal of this study was to develop an individualized risk prediction model that can be used to screen for asymptomatic pancreatic cancer in Korean men and women. Gender-specific risk prediction models for pancreatic cancer were developed using the Cox proportional hazards model based on an 8-year follow-up of a cohort study of 1,289,933 men and 557,701 women in Korea who had biennial examinations in 1996-1997. The performance of the models was evaluated with respect to their discrimination and calibration ability based on the C-statistic and Hosmer-Lemeshow type χ2 statistic. A total of 1,634 (0.13%) men and 561 (0.10%) women were newly diagnosed with pancreatic cancer. Age, height, BMI, fasting glucose, urine glucose, smoking, and age at smoking initiation were included in the risk prediction model for men. Height, BMI, fasting glucose, urine glucose, smoking, and drinking habit were included in the risk prediction model for women. Smoking was the most significant risk factor for developing pancreatic cancer in both men and women. The risk prediction model exhibited good discrimination and calibration ability, and in external validation it had excellent prediction ability. Gender-specific risk prediction models for pancreatic cancer were developed and validated for the first time. The prediction models will be a useful tool for detecting high-risk individuals who may benefit from increased surveillance for pancreatic cancer.

  13. Individualized computer-aided education in mammography based on user modeling: concept and preliminary experiments.

    Science.gov (United States)

    Mazurowski, Maciej A; Baker, Jay A; Barnhart, Huiman X; Tourassi, Georgia D

    2010-03-01

    The authors propose the framework for an individualized adaptive computer-aided educational system in mammography that is based on user modeling. The underlying hypothesis is that user models can be developed to capture the individual error making patterns of radiologists-in-training. In this pilot study, the authors test the above hypothesis for the task of breast cancer diagnosis in mammograms. The concept of a user model was formalized as the function that relates image features to the likelihood/extent of the diagnostic error made by a radiologist-in-training and therefore to the level of difficulty that a case will pose to the radiologist-in-training (or "user"). Then, machine learning algorithms were implemented to build such user models. Specifically, the authors explored k-nearest neighbor, artificial neural networks, and multiple regression for the task of building the model using observer data collected from ten Radiology residents at Duke University Medical Center for the problem of breast mass diagnosis in mammograms. For each resident, a user-specific model was constructed that predicts the user's expected level of difficulty for each presented case based on two BI-RADS image features. In the experiments, leave-one-out data handling scheme was applied to assign each case to a low-predicted-difficulty or a high-predicted-difficulty group for each resident based on each of the three user models. To evaluate whether the user model is useful in predicting difficulty, the authors performed statistical tests using the generalized estimating equations approach to determine whether the mean actual error is the same or not between the low-predicted-difficulty group and the high-predicted-difficulty group. When the results for all observers were pulled together, the actual errors made by residents were statistically significantly higher for cases in the high-predicted-difficulty group than for cases in the low-predicted-difficulty group for all modeling

  14. An individual-based model for population viability analysis of humpback chub in Grand Canyon

    Science.gov (United States)

    Pine, William Pine; Healy, Brian; Smith, Emily Omana; Trammell, Melissa; Speas, Dave; Valdez, Rich; Yard, Mike; Walters, Carl; Ahrens, Rob; Vanhaverbeke, Randy; Stone, Dennis; Wilson, Wade

    2013-01-01

    We developed an individual-based population viability analysis model (females only) for evaluating risk to populations from catastrophic events or conservation and research actions. This model tracks attributes (size, weight, viability, etc.) for individual fish through time and then compiles this information to assess the extinction risk of the population across large numbers of simulation trials. Using a case history for the Little Colorado River population of Humpback Chub Gila cypha in Grand Canyon, Arizona, we assessed extinction risk and resiliency to a catastrophic event for this population and then assessed a series of conservation actions related to removing specific numbers of Humpback Chub at different sizes for conservation purposes, such as translocating individuals to establish other spawning populations or hatchery refuge development. Our results suggested that the Little Colorado River population is generally resilient to a single catastrophic event and also to removals of larvae and juveniles for conservation purposes, including translocations to establish new populations. Our results also suggested that translocation success is dependent on similar survival rates in receiving and donor streams and low emigration rates from recipient streams. In addition, translocating either large numbers of larvae or small numbers of large juveniles has generally an equal likelihood of successful population establishment at similar extinction risk levels to the Little Colorado River donor population. Our model created a transparent platform to consider extinction risk to populations from catastrophe or conservation actions and should prove useful to managers assessing these risks for endangered species such as Humpback Chub.

  15. A holistic model for evaluating the impact of individual technology-enhanced learning resources.

    Science.gov (United States)

    Pickering, James D; Joynes, Viktoria C T

    2016-12-01

    The use of technology within education has now crossed the Rubicon; student expectations, the increasing availability of both hardware and software and the push to fully blended learning environments mean that educational institutions cannot afford to turn their backs on technology-enhanced learning (TEL). The ability to meaningfully evaluate the impact of TEL resources nevertheless remains problematic. This paper aims to establish a robust means of evaluating individual resources and meaningfully measure their impact upon learning within the context of the program in which they are used. Based upon the experience of developing and evaluating a range of mobile and desktop based TEL resources, this paper outlines a new four-stage evaluation process, taking into account learner satisfaction, learner gain, and the impact of a resource on both the individual and the institution in which it has been adapted. A new multi-level model of TEL resource evaluation is proposed, which includes a preliminary evaluation of need, learner satisfaction and gain, learner impact and institutional impact. Each of these levels are discussed in detail, and in relation to existing TEL evaluation frameworks. This paper details a holistic, meaningful evaluation model for individual TEL resources within the specific context in which they are used. It is proposed that this model is adopted to ensure that TEL resources are evaluated in a more meaningful and robust manner than is currently undertaken.

  16. The Roy Adaptation Model: A Theoretical Framework for Nurses Providing Care to Individuals With Anorexia Nervosa.

    Science.gov (United States)

    Jennings, Karen M

    Using a nursing theoretical framework to understand, elucidate, and propose nursing research is fundamental to knowledge development. This article presents the Roy Adaptation Model as a theoretical framework to better understand individuals with anorexia nervosa during acute treatment, and the role of nursing assessments and interventions in the promotion of weight restoration. Nursing assessments and interventions situated within the Roy Adaptation Model take into consideration how weight restoration does not occur in isolation but rather reflects an adaptive process within external and internal environments, and has the potential for more holistic care.

  17. Employment relations, flexibility and risk

    DEFF Research Database (Denmark)

    Jensen, Carsten Strøby

    Employment relations literature often distinguishes between social democratic/corporatist models of employment relations and liberal models of employment relations as they are seen as opposite or at least different ways of organizing labor markets. They are often characterized as having very...... different risk profiles in terms of relationships between employees, employers, and the state. Low levels of labor market regulation very often characterize the liberal models of employment relations as we know them from, for instance, the USA and the UK. This means that employment conditions are very often...

  18. Soldiers’ employment attitude and employability: An exploratory study

    Directory of Open Access Journals (Sweden)

    Peng Gao

    2015-04-01

    Full Text Available Purpose: Nowadays it is very difficult for Chinese retired soldiers to find proper jobs, and the primary reason is the significant gap between job requirements and soldiers owned job skills. Therefore, it is very important to improve the soldiers’ job skills and enhance their understanding of employment.Design/methodology/approach: This paper expands the study scope from the soldiers’ job skills to the employability, initiatively introduces the employment attitude which has obvious impact on the employment of soldiers, and analyses the influence that employment attitude can play on employability. At last, this paper develops statistical method to find the relationship between soldiers’ employment attitude and employability.Findings: The empirical analysis shows that soldiers’ employment attitude has the positive linkage with employability, which makes the employment attitude a measurable variable for the employability rather than an absolute standard.Research limitations/implications: According to the research purpose, more variables should be considered in the model, consequently, there are only three indicators to describe solders’ employment attitude and four indicators to describe solders’ employability.Originality/value: This paper takes research on soldiers’ employability in a new perspective. The soldiers’ employment attitude is served as the entry point, showing the influence that soldiers’ employment attitude has on employability.

  19. Individualized prediction of perineural invasion in colorectal cancer: development and validation of a radiomics prediction model.

    Science.gov (United States)

    Huang, Yanqi; He, Lan; Dong, Di; Yang, Caiyun; Liang, Cuishan; Chen, Xin; Ma, Zelan; Huang, Xiaomei; Yao, Su; Liang, Changhong; Tian, Jie; Liu, Zaiyi

    2018-02-01

    To develop and validate a radiomics prediction model for individualized prediction of perineural invasion (PNI) in colorectal cancer (CRC). After computed tomography (CT) radiomics features extraction, a radiomics signature was constructed in derivation cohort (346 CRC patients). A prediction model was developed to integrate the radiomics signature and clinical candidate predictors [age, sex, tumor location, and carcinoembryonic antigen (CEA) level]. Apparent prediction performance was assessed. After internal validation, independent temporal validation (separate from the cohort used to build the model) was then conducted in 217 CRC patients. The final model was converted to an easy-to-use nomogram. The developed radiomics nomogram that integrated the radiomics signature and CEA level showed good calibration and discrimination performance [Harrell's concordance index (c-index): 0.817; 95% confidence interval (95% CI): 0.811-0.823]. Application of the nomogram in validation cohort gave a comparable calibration and discrimination (c-index: 0.803; 95% CI: 0.794-0.812). Integrating the radiomics signature and CEA level into a radiomics prediction model enables easy and effective risk assessment of PNI in CRC. This stratification of patients according to their PNI status may provide a basis for individualized auxiliary treatment.

  20. Process Mining for Individualized Behavior Modeling Using Wireless Tracking in Nursing Homes

    Directory of Open Access Journals (Sweden)

    Vicente Traver

    2013-11-01

    Full Text Available The analysis of human behavior patterns is increasingly used for several research fields. The individualized modeling of behavior using classical techniques requires too much time and resources to be effective. A possible solution would be the use of pattern recognition techniques to automatically infer models to allow experts to understand individual behavior. However, traditional pattern recognition algorithms infer models that are not readily understood by human experts. This limits the capacity to benefit from the inferred models. Process mining technologies can infer models as workflows, specifically designed to be understood by experts, enabling them to detect specific behavior patterns in users. In this paper, the eMotiva process mining algorithms are presented. These algorithms filter, infer and visualize workflows. The workflows are inferred from the samples produced by an indoor location system that stores the location of a resident in a nursing home. The visualization tool is able to compare and highlight behavior patterns in order to facilitate expert understanding of human behavior. This tool was tested with nine real users that were monitored for a 25-week period. The results achieved suggest that the behavior of users is continuously evolving and changing and that this change can be measured, allowing for behavioral change detection.

  1. Process Mining for Individualized Behavior Modeling Using Wireless Tracking in Nursing Homes

    Science.gov (United States)

    Fernández-Llatas, Carlos; Benedi, José-Miguel; García-Gómez, Juan M.; Traver, Vicente

    2013-01-01

    The analysis of human behavior patterns is increasingly used for several research fields. The individualized modeling of behavior using classical techniques requires too much time and resources to be effective. A possible solution would be the use of pattern recognition techniques to automatically infer models to allow experts to understand individual behavior. However, traditional pattern recognition algorithms infer models that are not readily understood by human experts. This limits the capacity to benefit from the inferred models. Process mining technologies can infer models as workflows, specifically designed to be understood by experts, enabling them to detect specific behavior patterns in users. In this paper, the eMotiva process mining algorithms are presented. These algorithms filter, infer and visualize workflows. The workflows are inferred from the samples produced by an indoor location system that stores the location of a resident in a nursing home. The visualization tool is able to compare and highlight behavior patterns in order to facilitate expert understanding of human behavior. This tool was tested with nine real users that were monitored for a 25-week period. The results achieved suggest that the behavior of users is continuously evolving and changing and that this change can be measured, allowing for behavioral change detection. PMID:24225907

  2. Oxygen consumption prediction models for individual and combination materials handling tasks.

    Science.gov (United States)

    Dempsey, Patrick G; Ciriello, Vincent M; Maikala, Rammohan V; O'Brien, Niall V

    2008-11-01

    An experiment was conducted to develop models to predict oxygen consumption of males and females engaged in common materials handling tasks including lifting, lowering, pushing, pulling, (de)palletising and combination tasks involving lifting or lowering a box and carrying it a set distance and lifting or lowering it to the destination. Nineteen male and 19 female subjects participated in the study. A psychophysical approach was used to set load limits for individual subjects for the oxygen consumption protocol. The 8398 oxygen consumption values collected were entered into the initial regression analyses and 168 potential outliers were removed before the final models were run. In addition to relevant task variables, body weight was a significant predictor variable in all models. The r(2) values for the final models ranged from 0.54 to 0.82 and the root mean square errors ranged from 90.2 ml to 294.8 ml.

  3. An individual-based model for biofilm formation at liquid surfaces.

    Science.gov (United States)

    Ardré, Maxime; Henry, Hervé; Douarche, Carine; Plapp, Mathis

    2015-12-10

    The bacterium Bacillus subtilis frequently forms biofilms at the interface between the culture medium and the air. We present a mathematical model that couples a description of bacteria as individual discrete objects to the standard advection-diffusion equations for the environment. The model takes into account two different bacterial phenotypes. In the motile state, bacteria swim and perform a run-and-tumble motion that is biased toward regions of high oxygen concentration (aerotaxis). In the matrix-producer state they excrete extracellular polymers, which allows them to connect to other bacteria and to form a biofilm. Bacteria are also advected by the fluid, and can trigger bioconvection. Numerical simulations of the model reproduce all the stages of biofilm formation observed in laboratory experiments. Finally, we study the influence of various model parameters on the dynamics and morphology of biofilms.

  4. Modelling and Bayesian adaptive prediction of individual patients’ tumour volume change during radiotherapy

    International Nuclear Information System (INIS)

    Tariq, Imran; Chen, Tao; Kirkby, Norman F; Jena, Rajesh

    2016-01-01

    The aim of this study is to develop a mathematical modelling method that can predict individual patients’ response to radiotherapy, in terms of tumour volume change during the treatment. The main concept is to start from a population-average model, which is subsequently updated from an individual’s tumour volume measurement. The model becomes increasingly personalised and so too does the prediction it produces. This idea of adaptive prediction was realised by using a Bayesian approach for updating the model parameters. The feasibility of the developed method was demonstrated on the data from 25 non-small cell lung cancer patients treated with helical tomotherapy, during which tumour volume was measured from daily imaging as part of the image-guided radiotherapy. The method could provide useful information for adaptive treatment planning and dose scheduling based on the patient’s personalised response. (paper)

  5. The modelled benefits of individualizing radiotherapy patients' dose using cellular radiosensitivity assays with inherent variability

    International Nuclear Information System (INIS)

    Mackay, R.I.; Hendry, J.H.

    1999-01-01

    Objective: To model the increases in local tumour control that may be achieved, without increasing normal tissue complications, by prescribing a patient's dose based on cellular radiosensitivity measured using an assay possessing inherent variability.Method: Patient populations with varying radiosensitivity were simulated, based on measured distributions among cancer patients of the surviving fraction of their fibroblasts given a dose of 2 Gy in vitro (SF 2 ). The dose-response curve for complications in the population was assessed using a formula relating SF 2 to normal tissue complication probability (NTCP), by summing the data for the individuals. This curve was similar to clinically-derived dose-response curves. The effect of individualizing the patients' doses was explored, based on individual radiosensitivities measured by SF 2 , so that every patient had the same low (5%) value of NTCP.Results: It was found that a significant gain (up to around 30%) in tumour control probability (TCP) was predicted for the population when the doses were individualized using a predictive assay result strongly correlated with NTCP. A greater gain in TCP was predicted when each of the individuals were assumed to have a higher sensitivity and the distribution of radiosensitivity in the population was widened to compensate. The gain in TCP was less (around 20%) when considering less-sensitive patients and a narrower distribution of radiosensitivities. The effect of assay variability and other factors that could affect the predictive power of the assay was simulated. Assay variability and an imperfect correlation between in vitro cell survival and tissue complications, rapidly increased the NTCP for the population when treated with individualized doses. However the individualized doses could be reduced so that NTCP declined to an acceptable level, but in this case the TCP for the population also declined. For example, when the assay variability was half the true variability in SF

  6. Use of an individual-based simulation model to explore and evaluate potential insecticide resistance management strategies.

    Science.gov (United States)

    Slater, Russell; Stratonovitch, Pierre; Elias, Jan; Semenov, Mikhail A; Denholm, Ian

    2017-07-01

    Tools with the potential to predict risks of insecticide resistance and aid the evaluation and design of resistance management tactics are of value to all sectors of the pest management community. Here we describe use of a versatile individual-based model of resistance evolution to simulate how strategies employing single and multiple insecticides influence resistance development in the pollen beetle, Meligethes aeneus. Under repeated exposure to a single insecticide, resistance evolved faster to a pyrethroid (lambda-cyhalothrin) than to a pyridine azomethane (pymetrozine), due to difference in initial efficacy. A mixture of these compounds delayed resistance compared to use of single products. The effectiveness of rotations depended on the sequence in which compounds were applied in response to pest density thresholds. Effectiveness of a mixture strategy declined with reductions in grower compliance. At least 50% compliance was needed to cause some delay in resistance development. No single strategy meets all requirements for managing resistance. It is important to evaluate factors that prevail under particular pest management scenarios. The model used here provides operators with a valuable means for evaluating and extending sound resistance management advice, as well as understanding needs and opportunities offered by new control techniques. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. Institutionalized Employer Collective Action

    DEFF Research Database (Denmark)

    Ibsen, Christian Lyhne; Navrbjerg, Steen Erik

    2016-01-01

    Recent studies show that employer associations continue to exist in new ways despite internationalisation of the economy, liberalisation of markets and the decline of trade unions. This paradox raises two questions regarding EOs in today’s labour markets: Which employers join employer associations...... and what kind of services do EOs offer employers? This article explores these questions using two comprehensive surveys on EOs in Denmark – a prominent case of coordinated market economies. The main finding of the analyses is that collective activities vis-à-vis trade unions and government are still...... important but that individual and selective goods are just as important for recruitment and retention of members. The most important predictor of EO-membership is the existence of a collective agreement. Local union power and representation is not significant which supports the idea that EOs...

  8. Impact of simulating borderline personality disorder on the MMPI-2: a costs-benefits model employing base rates.

    Science.gov (United States)

    Sivec, H J; Hilsenroth, M J; Lynn, S J

    1995-04-01

    This investigation extends current work on the impact of role-specific response sets on dissimulated Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) profiles. Specifically, one group of subjects was given specific symptom information and instructed to simulate borderline personality disorder on the MMPI-2. This dissimulation performance was compared to a clinical comparison group of clients diagnosed with borderline personality disorder, a group of subjects instructed to simulate major depression, and a group of subjects who responded honestly to the MMPI-2. In both simulating conditions, subjects produced significantly higher elevations on a majority of clinical and validity scales than the clinical comparison group. A rigorous evaluation of the F scale was conducted to provide a range of predictive values for different F scale cutting scores for detecting malingering. Sensitivity, specificity, and positive and negative predictive power were computed for this range of F scale values. A similar analysis was conducted for the Borderline Personality Disorder Scale (BPDsc) of Morey, Waugh, and Blashfield (1985). These results are integrated with extant research. A costs-benefits model is proposed for employing F scale cutting scores in clinical situations with different base rates of malingering.

  9. Targeted screening of individuals at high risk for pancreatic cancer: results of a simulation model.

    Science.gov (United States)

    Pandharipande, Pari V; Heberle, Curtis; Dowling, Emily C; Kong, Chung Yin; Tramontano, Angela; Perzan, Katherine E; Brugge, William; Hur, Chin

    2015-04-01

    To identify when, from the standpoint of relative risk, magnetic resonance (MR) imaging-based screening may be effective in patients with a known or suspected genetic predisposition to pancreatic cancer. The authors developed a Markov model of pancreatic ductal adenocarcinoma (PDAC). The model was calibrated to National Cancer Institute Surveillance, Epidemiology, and End Results registry data and informed by the literature. A hypothetical screening strategy was evaluated in which all population individuals underwent one-time MR imaging screening at age 50 years. Screening outcomes for individuals with an average risk for PDAC ("base case") were compared with those for individuals at an increased risk to assess for differential benefits in populations with a known or suspected genetic predisposition. Effects of varying key inputs, including MR imaging performance, surgical mortality, and screening age, were evaluated with a sensitivity analysis. RESULTS In the base case, screening resulted in a small number of cancer deaths averted (39 of 100 000 men, 38 of 100 000 women) and a net decrease in life expectancy (-3 days for men, -4 days for women), which was driven by unnecessary pancreatic surgeries associated with false-positive results. Life expectancy gains were achieved if an individual's risk for PDAC exceeded 2.4 (men) or 2.7 (women) times that of the general population. When relative risk increased further, for example to 30 times that of the general population, averted cancer deaths and life expectancy gains increased substantially (1219 of 100 000 men, life expectancy gain: 65 days; 1204 of 100 000 women, life expectancy gain: 71 days). In addition, results were sensitive to MR imaging specificity and the surgical mortality rate. Although PDAC screening with MR imaging for the entire population is not effective, individuals with even modestly increased risk may benefit. © RSNA, 2014 Online supplemental material is available for this article.

  10. The impact of individual and organisational factors on engagement of individuals with intellectual disability living in community group homes: a multilevel model.

    Science.gov (United States)

    Qian, X; Tichá, R; Larson, S A; Stancliffe, R J; Wuorio, A

    2015-06-01

    Being engaged in daily activities is a strong indicator of quality of life for individuals with intellectual disability (ID) who live in small community group homes. This study aimed to identify individual and organisational factors that predict high levels of engagement. Individuals with ID (n = 78), direct support professionals (DSPs; n = 174) and supervisors (n = 21) from 21 US group homes participated in the study. For each individual with ID, we conducted 80 min of observation at the person's residence. Information was also gathered regarding demographic characteristics, DSP competence, supervisor years of experience and management practices. Data were analysed using multilevel modelling. On average, individuals were engaged in social activities 12% of observed time and non-social activities 35% of the time. Individuals with greater adaptive skills who were supported by more competent staff showed significantly higher levels of social engagement. Individuals with less severe deficits in adaptive behaviours and less challenging behaviour showed higher levels of non-social engagement. Although none of the factors related to group homes were significant, 24% of the variance in non-social engagement existed among group homes. These results suggested that engagement is a dynamic construct. The extent to which an individual with ID is engaged in daily life is a result of interplay between the individual's characteristics and the group home environment. Future research is needed to investigate the influence of variables specific to the group home on the engagement level of individuals with disabilities. © 2014 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

  11. Systematic comparison of barriers for heavy-ion fusion calculated on the basis of the double-folding model by employing two versions of nucleon–nucleon interaction

    Energy Technology Data Exchange (ETDEWEB)

    Gontchar, I. I. [Omsk State Transport University (Russian Federation); Chushnyakova, M. V., E-mail: maria.chushnyakova@gmail.com [Omsk State Technical University (Russian Federation)

    2016-07-15

    A systematic calculation of barriers for heavy-ion fusion was performed on the basis of the double-folding model by employing two versions of an effective nucleon–nucleon interaction: M3Y interaction and Migdal interaction. The results of calculations by the Hartree–Fockmethod with the SKX coefficients were taken for nuclear densities. The calculations reveal that the fusion barrier is higher in the case of employing theMigdal interaction than in the case of employing the Ðœ3Y interaction. In view of this, the use of the Migdal interaction in describing heavy-ion fusion is questionable.

  12. Knowledge-based IMRT planning for individual liver cancer patients using a novel specific model.

    Science.gov (United States)

    Yu, Gang; Li, Yang; Feng, Ziwei; Tao, Cheng; Yu, Zuyi; Li, Baosheng; Li, Dengwang

    2018-03-27

    The purpose of this work is to benchmark RapidPlan against clinical plans for liver Intensity-modulated radiotherapy (IMRT) treatment of patients with special anatomical characteristics, and to investigate the prediction capability of the general model (Model-G) versus our specific model (Model-S). A library consisting of 60 liver cancer patients with IMRT planning was used to set up two models (Model-S, Model-G), using the RapidPlan knowledge-based planning system. Model-S consisted of 30 patients with special anatomical characteristics where the distance from planning target volume (PTV) to the right kidney was less than three centimeters and Model-G was configurated using all 60 patients in this library. Knowledge-based IMRT plans were created for the evaluation group formed of 13 patients similar to those included in Model-S by Model-G, Model-S and manually (M), named RPG-plans, RPS-plans and M-plans, respectively. The differences in the dose-volume histograms (DVHs) were compared, not only between RP-plans and their respective M-plans, but also between RPG-plans and RPS-plans. For all 13 patients, RapidPlan could automatically produce clinically acceptable plans. Comparing RP-plans to M-plans, RP-plans improved V 95% of PTV and had greater dose sparing in the right kidney. For the normal liver, RPG-plans delivered similar doses, while RPS-plans delivered a higher dose than M-plans. With respect to RapidPlan models, RPS-plans had better conformity index (CI) values and delivered lower doses to the right kidney V 20Gy and maximizing point doses to spinal cord, while delivering higher doses to the normal liver. The study shows that RapidPlan can create high-quality plans, and our specific model can improve the CI of PTV, resulting in more sparing of OAR in IMRT for individual liver cancer patients.

  13. Sensitivity analysis of an individual-based model for simulation of influenza epidemics.

    Directory of Open Access Journals (Sweden)

    Elaine O Nsoesie

    Full Text Available Individual-based epidemiology models are increasingly used in the study of influenza epidemics. Several studies on influenza dynamics and evaluation of intervention measures have used the same incubation and infectious period distribution parameters based on the natural history of influenza. A sensitivity analysis evaluating the influence of slight changes to these parameters (in addition to the transmissibility would be useful for future studies and real-time modeling during an influenza pandemic.In this study, we examined individual and joint effects of parameters and ranked parameters based on their influence on the dynamics of simulated epidemics. We also compared the sensitivity of the model across synthetic social networks for Montgomery County in Virginia and New York City (and surrounding metropolitan regions with demographic and rural-urban differences. In addition, we studied the effects of changing the mean infectious period on age-specific epidemics. The research was performed from a public health standpoint using three relevant measures: time to peak, peak infected proportion and total attack rate. We also used statistical methods in the design and analysis of the experiments. The results showed that: (i minute changes in the transmissibility and mean infectious period significantly influenced the attack rate; (ii the mean of the incubation period distribution appeared to be sufficient for determining its effects on the dynamics of epidemics; (iii the infectious period distribution had the strongest influence on the structure of the epidemic curves; (iv the sensitivity of the individual-based model was consistent across social networks investigated in this study and (v age-specific epidemics were sensitive to changes in the mean infectious period irrespective of the susceptibility of the other age groups. These findings suggest that small changes in some of the disease model parameters can significantly influence the uncertainty

  14. Comparison of individual-based modeling and population approaches for prediction of foodborne pathogens growth.

    Science.gov (United States)

    Augustin, Jean-Christophe; Ferrier, Rachel; Hezard, Bernard; Lintz, Adrienne; Stahl, Valérie

    2015-02-01

    Individual-based modeling (IBM) approach combined with the microenvironment modeling of vacuum-packed cold-smoked salmon was more effective to describe the variability of the growth of a few Listeria monocytogenes cells contaminating irradiated salmon slices than the traditional population models. The IBM approach was particularly relevant to predict the absence of growth in 25% (5 among 20) of artificially contaminated cold-smoked salmon samples stored at 8 °C. These results confirmed similar observations obtained with smear soft cheese (Ferrier et al., 2013). These two different food models were used to compare the IBM/microscale and population/macroscale modeling approaches in more global exposure and risk assessment frameworks taking into account the variability and/or the uncertainty of the factors influencing the growth of L. monocytogenes. We observed that the traditional population models significantly overestimate exposure and risk estimates in comparison to IBM approach when contamination of foods occurs with a low number of cells (population model were characterized by a great uncertainty. The overestimation was mainly linked to the ability of IBM to predict no growth situations rather than the consideration of microscale environment. On the other hand, when the aim of quantitative risk assessment studies is only to assess the relative impact of changes in control measures affecting the growth of foodborne bacteria, the two modeling approach gave similar results and the simplest population approach was suitable. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis (TRIPOD): The TRIPOD Statement.

    Science.gov (United States)

    Collins, Gary S; Reitsma, Johannes B; Altman, Douglas G; Moons, Karel G M

    2015-06-01

    Prediction models are developed to aid health care providers in estimating the probability or risk that a specific disease or condition is present (diagnostic models) or that a specific event will occur in the future (prognostic models), to inform their decision making. However, the overwhelming evidence shows that the quality of reporting of prediction model studies is poor. Only with full and clear reporting of information on all aspects of a prediction model can risk of bias and potential usefulness of prediction models be adequately assessed. The Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) Initiative developed a set of recommendations for the reporting of studies developing, validating, or updating a prediction model, whether for diagnostic or prognostic purposes. This article describes how the TRIPOD Statement was developed. An extensive list of items based on a review of the literature was created, which was reduced after a Web-based survey and revised during a 3-day meeting in June 2011 with methodologists, health care professionals, and journal editors. The list was refined during several meetings of the steering group and in e-mail discussions with the wider group of TRIPOD contributors. The resulting TRIPOD Statement is a checklist of 22 items, deemed essential for transparent reporting of a prediction model study. The TRIPOD Statement aims to improve the transparency of the reporting of a prediction model study regardless of the study methods used. The TRIPOD Statement is best used in conjunction with the TRIPOD explanation and elaboration document. To aid the editorial process and readers of prediction model studies, it is recommended that authors include a completed checklist in their submission (also available at www.tripod-statement.org). The Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) Initiative developed a set of recommendations

  16. Prediction of hybrid performance in maize with a ridge regression model employed to DNA markers and mRNA transcription profiles.

    Science.gov (United States)

    Zenke-Philippi, Carola; Thiemann, Alexander; Seifert, Felix; Schrag, Tobias; Melchinger, Albrecht E; Scholten, Stefan; Frisch, Matthias

    2016-03-29

    Ridge regression models can be used for predicting heterosis and hybrid performance. Their application to mRNA transcription profiles has not yet been investigated. Our objective was to compare the prediction accuracy of models employing mRNA transcription profiles with that of models employing genome-wide markers using a data set of 98 maize hybrids from a breeding program. We predicted hybrid performance and mid-parent heterosis for grain yield and grain dry matter content and employed cross validation to assess the prediction accuracy. Prediction with a ridge regression model using random effects for mRNA transcription profiles resulted in similar prediction accuracies than employing the model to DNA markers. For hybrids, of which none of the parental inbred lines was part of the training set, the ridge regression model did not reach the prediction accuracy that was obtained with a model using transcriptome-based distances. We conclude that mRNA transcription profiles are a promising alternative to DNA markers for hybrid prediction, but further studies with larger data sets are required to investigate the superiority of alternative prediction models.

  17. Measurement invariance within and between individuals: a distinct problem in testing the equivalence of intra- and inter-individual model structures.

    Science.gov (United States)

    Adolf, Janne; Schuurman, Noémi K; Borkenau, Peter; Borsboom, Denny; Dolan, Conor V

    2014-01-01

    We address the question of equivalence between modeling results obtained on intra-individual and inter-individual levels of psychometric analysis. Our focus is on the concept of measurement invariance and the role it may play in this context. We discuss this in general against the background of the latent variable paradigm, complemented by an operational demonstration in terms of a linear state-space model, i.e., a time series model with latent variables. Implemented in a multiple-occasion and multiple-subject setting, the model simultaneously accounts for intra-individual and inter-individual differences. We consider the conditions-in terms of invariance constraints-under which modeling results are generalizable (a) over time within subjects, (b) over subjects within occasions, and (c) over time and subjects simultaneously thus implying an equivalence-relationship between both dimensions. Since we distinguish the measurement model from the structural model governing relations between the latent variables of interest, we decompose the invariance constraints into those that involve structural parameters and those that involve measurement parameters and relate to measurement invariance. Within the resulting taxonomy of models, we show that, under the condition of measurement invariance over time and subjects, there exists a form of structural equivalence between levels of analysis that is distinct from full structural equivalence, i.e., ergodicity. We demonstrate how measurement invariance between and within subjects can be tested in the context of high-frequency repeated measures in personality research. Finally, we relate problems of measurement variance to problems of non-ergodicity as currently discussed and approached in the literature.

  18. Modeling the Role of Networks and Individual Differences in Inter-Group Violence.

    Science.gov (United States)

    Isakov, Alexander; Holcomb, Amelia; Glowacki, Luke; Christakis, Nicholas A

    2016-01-01

    There is significant heterogeneity within and between populations in their propensity to engage in conflict. Most research has neglected the role of within-group effects in social networks in contributing to between-group violence and focused instead on the precursors and consequences of violence, or on the role of between-group ties. Here, we explore the role of individual variation and of network structure within a population in promoting and inhibiting group violence towards other populations. Motivated by ethnographic observations of collective behavior in a small-scale society, we describe a model with differentiated roles for individuals embedded within friendship networks. Using a simple model based on voting-like dynamics, we explore several strategies for influencing group-level behavior. When we consider changing population level attitude changes and introducing control nodes separately, we find that a particularly effective control strategy relies on exploiting network degree. We also suggest refinements to our model such as tracking fine-grained information spread dynamics that can lead to further enrichment in using evolutionary game theory models for sociological phenomena.

  19. Modeling the Role of Networks and Individual Differences in Inter-Group Violence.

    Directory of Open Access Journals (Sweden)

    Alexander Isakov

    Full Text Available There is significant heterogeneity within and between populations in their propensity to engage in conflict. Most research has neglected the role of within-group effects in social networks in contributing to between-group violence and focused instead on the precursors and consequences of violence, or on the role of between-group ties. Here, we explore the role of individual variation and of network structure within a population in promoting and inhibiting group violence towards other populations. Motivated by ethnographic observations of collective behavior in a small-scale society, we describe a model with differentiated roles for individuals embedded within friendship networks. Using a simple model based on voting-like dynamics, we explore several strategies for influencing group-level behavior. When we consider changing population level attitude changes and introducing control nodes separately, we find that a particularly effective control strategy relies on exploiting network degree. We also suggest refinements to our model such as tracking fine-grained information spread dynamics that can lead to further enrichment in using evolutionary game theory models for sociological phenomena.

  20. Navigational efficiency in a biased and correlated random walk model of individual animal movement.

    Science.gov (United States)

    Bailey, Joseph D; Wallis, Jamie; Codling, Edward A

    2018-01-01

    Understanding how an individual animal is able to navigate through its environment is a key question in movement ecology that can give insight into observed movement patterns and the mechanisms behind them. Efficiency of navigation is important for behavioral processes at a range of different spatio-temporal scales, including foraging and migration. Random walk models provide a standard framework for modeling individual animal movement and navigation. Here we consider a vector-weighted biased and correlated random walk (BCRW) model for directed movement (taxis), where external navigation cues are balanced with forward persistence. We derive a mathematical approximation of the expected navigational efficiency for any BCRW of this form and confirm the model predictions using simulations. We demonstrate how the navigational efficiency is related to the weighting given to forward persistence and external navigation cues, and highlight the counter-intuitive result that for low (but realistic) levels of error on forward persistence, a higher navigational efficiency is achieved by giving more weighting to this indirect navigation cue rather than direct navigational cues. We discuss and interpret the relevance of these results for understanding animal movement and navigation strategies. © 2017 by the Ecological Society of America.

  1. Predicting the efficacy of radiotherapy in individual glioblastoma patients in vivo: a mathematical modeling approach

    International Nuclear Information System (INIS)

    Rockne, R; Alvord, E C Jr; Swanson, K R; Rockhill, J K; Kalet, I; Hendrickson, K; Mrugala, M; Spence, A M; Lai, A; Cloughesy, T

    2010-01-01

    Glioblastoma multiforme (GBM) is the most malignant form of primary brain tumors known as gliomas. They proliferate and invade extensively and yield short life expectancies despite aggressive treatment. Response to treatment is usually measured in terms of the survival of groups of patients treated similarly, but this statistical approach misses the subgroups that may have responded to or may have been injured by treatment. Such statistics offer scant reassurance to individual patients who have suffered through these treatments. Furthermore, current imaging-based treatment response metrics in individual patients ignore patient-specific differences in tumor growth kinetics, which have been shown to vary widely across patients even within the same histological diagnosis and, unfortunately, these metrics have shown only minimal success in predicting patient outcome. We consider nine newly diagnosed GBM patients receiving diagnostic biopsy followed by standard-of-care external beam radiation therapy (XRT). We present and apply a patient-specific, biologically based mathematical model for glioma growth that quantifies response to XRT in individual patients in vivo. The mathematical model uses net rates of proliferation and migration of malignant tumor cells to characterize the tumor's growth and invasion along with the linear-quadratic model for the response to radiation therapy. Using only routinely available pre-treatment MRIs to inform the patient-specific bio-mathematical model simulations, we find that radiation response in these patients, quantified by both clinical and model-generated measures, could have been predicted prior to treatment with high accuracy. Specifically, we find that the net proliferation rate is correlated with the radiation response parameter (r = 0.89, p = 0.0007), resulting in a predictive relationship that is tested with a leave-one-out cross-validation technique. This relationship predicts the tumor size post-therapy to within inter

  2. Optimization of an individual re-identification modeling process using biometric features

    Energy Technology Data Exchange (ETDEWEB)

    Heredia-Langner, Alejandro; Amidan, Brett G.; Matzner, Shari; Jarman, Kristin H.

    2014-09-24

    We present results from the optimization of a re-identification process using two sets of biometric data obtained from the Civilian American and European Surface Anthropometry Resource Project (CAESAR) database. The datasets contain real measurements of features for 2378 individuals in a standing (43 features) and seated (16 features) position. A genetic algorithm (GA) was used to search a large combinatorial space where different features are available between the probe (seated) and gallery (standing) datasets. Results show that optimized model predictions obtained using less than half of the 43 gallery features and data from roughly 16% of the individuals available produce better re-identification rates than two other approaches that use all the information available.

  3. Individual decision-making in the causal pathway to addiction: contributions and limitations of rodent models.

    Science.gov (United States)

    Ahmed, Serge H

    2018-01-01

    The causal pathway from vulnerability to drug use and addiction involves a complex interaction between genetic, environmental, and behavioral factors. An individual can intervene on this causal pathway by two major types of individual decision. There is the inaugural, momentous decision to use a drug for the first time. This decision is influenced by both prior knowledge on the drug and its expected effects, and also by prior self-knowledge on one's own vulnerability. After an individual has used a drug for the first time, there is the decision to repeat drug use. This decision is influenced by the same factors that were involved in the inaugural decision to initiate drug use, except for one crucial difference. The first drug use has now acted on the individual, changing its brain acutely and also potentially persistently in a way that could bias subsequent decision-making in favor of repeated drug use. The goal of this review article is to assess the contributions and limitations of rodent models (i.e., rats, mice) to understand how prior drug use can influence decision-making in a way that favors future drug use. Overall, research on rodents shows that prior drug use can increase impulsive, risky and/or potentially harmful decision-making. However, this does not apparently translate into more drug use when rodents have the choice between a drug and a competing, nondrug option, except when the expected value of the latter is considerably decreased. The delayed drug reward hypothesis is developed to resolve and explain this apparent discrepancy. This novel hypothesis makes several unique predictions, some of them counterintuitive, and suggests that extrapolation of rodent research to humans should not only take into account differences in drug choice situations but also inherent species-specific differences in individual decision-making. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Developing a new individualized 3-node model for evaluating the effects of personal factors on thermal sensation.

    Science.gov (United States)

    Davoodi, Farzin; Hasanzadeh, Hasan; Alireza Zolfaghari, Seyed; Maerefat, Mehdi

    2017-10-01

    Individual differences, such as weight, height, gender, age, and Basal Metabolic Rate (BMR), between human subjects can significantly affect body thermoregulatory mechanisms. Therefore, application of common population-based thermal comfort models cannot provide accurate results for an individual's thermal sensation. Based on the standard thermal models, including those of Fanger and Gagge, individual parameters are not considered in the evaluation of thermal sensations. Thus, these simplified standard models have some limitations under varied individual conditions. In this study, a new individualized thermal comfort model is presented on the basis of a simplified 3-node model. This model was developed by regarding the effects of individual characteristics, such as age, gender, Body Mass Index (BMI), and BMR on the thermal sensations of the bare and clothed parts of the body. A good agreement was found in the current model, which was verified based on the experimental data. In conclusion, the results indicated that the mean error in the prediction of skin temperature decreased from 1.2°C to 0.4°C when using the new individual model instead of a non-individualized 3-node model. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. USING ECO-EVOLUTIONARY INDIVIDUAL-BASED MODELS TO INVESTIGATE SPATIALLY-DEPENDENT PROCESSES IN CONSERVATION GENETICS

    Science.gov (United States)

    Eco-evolutionary population simulation models are powerful new forecasting tools for exploring management strategies for climate change and other dynamic disturbance regimes. Additionally, eco-evo individual-based models (IBMs) are useful for investigating theoretical feedbacks ...

  6. Real beards and real networks: a spin-glass model for interacting individuals

    Science.gov (United States)

    O'Neale, Dion

    ''I want to be different, just like all the other different people'' sang the band King Missile. Whether they are the Beatniks of the 1950s, the punks of the 1970s, or the hipsters of today, non-conformists often tend to look the same, seemingly at odds with their goal of non-conformity. The spin-glass model, originally developed to describe the interaction of magnetic spins, and since applied to situations as diverse as the electrical activity of networks of neurons, to trades on a financial market, has recently been used in social science to study populations of interacting individuals comprised of a mix of both conformists and anti-conformists - or hipsters. Including delay effects for the interactions between individuals has been shown to give a system with non-trivial dynamics with a phase transition from stable behaviour to periodic switching between two states (let's call them bushy bearded and clean shaven). Analytic solutions to such a model are possible, but only for particular assumptions about the interaction and delay matrices. In this work we will show what happens when the interactions in the model are based on real-world networks with ''small-world'' effects and clustering.

  7. Implementing the employability agenda

    DEFF Research Database (Denmark)

    Lee, Donna; Snaith, Holly Grace; Foster, Emma

    2014-01-01

    This article draws on research commissioned by the Higher Education Academy (HEA) and conducted during 2013. It interrogates the ways in which the employability agenda has been fed through to the level of individual politics departments. The project was particularly concerned with establishing...... whether, and how, colleagues in politics and international relations (IR) had taken ownership of student employability at the level of the curriculum. In the article, the key findings of the research are summarised. There is also discussion of the (sometimes troubling) professional implications...... of infusing concern for graduate outcomes within a pedagogic framework that emphasises critical engagement with the underpinning political structures of the labour market....

  8. Health behavior models for informing digital technology interventions for individuals with mental illness.

    Science.gov (United States)

    Naslund, John A; Aschbrenner, Kelly A; Kim, Sunny Jung; McHugo, Gregory J; Unützer, Jürgen; Bartels, Stephen J; Marsch, Lisa A

    2017-09-01

    Theoretical models offer valuable insights for designing effective and sustainable behavioral health interventions, yet the application of theory for informing digital technology interventions for people with mental illness has received limited attention. We offer a perspective on the importance of applying behavior theories and models to developing digital technology interventions for addressing mental and physical health concerns among people with mental illness. In this commentary, we summarize prominent theories of human behavior, highlight key theoretical constructs, and identify opportunities to inform digital health interventions for people with mental illness. We consider limitations with existing theories and models, and examine recent theoretical advances that can specifically guide development of digital technology interventions. Established behavioral frameworks including health belief model, theory of planned behavior, transtheoretical model, and social cognitive theory consist of important and overlapping constructs that can inform digital health interventions for people with mental illness. As digital technologies continue to evolve and enable longitudinal data collection, real-time behavior monitoring, and adaptive features tailored to users' changing needs over time, there are new opportunities to broaden our understanding of health behaviors and mechanisms of behavior change. Recent advances include dynamic models of behavior, persuasive system design, the behavioral intervention technology model, and behavioral models for just-in-time adaptive interventions. Behavior theories offer advantages for guiding use of digital technologies. Future researchers must explore how theoretical models can effectively advance efforts to develop, evaluate, and disseminate digital health interventions targeting individuals with mental illness. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Individual variations in numerically modeled human muscle and temporomandibular joint forces during static biting.

    Science.gov (United States)

    Iwasaki, Laura R; Thornton, Benjamin R; McCall, Willard D; Nickel, Jeffrey C

    2004-01-01

    To test the effects of occlusal force (OF) angle on the variations in predicted muscle and temporomandibular joint (TMJ) forces during unilateral molar bites. The craniomandibular (CM) geometries of 21 individuals were determined from lateral and posteroanterior cephalometric radiographs. These geometries were used in a numerical model based on minimization of muscle effort. This model was previously validated for this subject group through the use of jaw tracking and electromyographic data. The model predicted muscle and TMJ forces associated with static OFs on the right mandibular first molar. OF angle was varied from vertical to 40 degrees in the buccal and lingual directions, in increments of 10 degrees. Intra- and intersubject variations in predicted muscle and TMJ forces for unilateral molar biting were dependent on OF angle and CM geometry. Nonvertical OFs were associated with either large anterior temporalis muscle forces (> 100% of applied OF in 3 subjects) or large inferior lateral pterygoid muscle forces (> 90% of applied OF in 3 subjects). On average, vertically and buccally directed OFs were associated with higher mean contralateral TMJ forces (60% of applied OF, SD 12%). Two subjects had large ipsilateral or contralateral TMJ forces (> 90% of applied OF). In a group of healthy subjects, depending on the individual CM geometry, large muscle and/or TMJ forces were predicted to be associated with specific unilateral molar OF angles. Propensities to increased muscle or joint forces may be predisposing factors in the development of myofascial pain or intracapsular disease. The results may explain, in part, the variation in location of symptoms in individuals who first present with temporomandibular disorders.

  10. An Individual-Based Diploid Model Predicts Limited Conditions Under Which Stochastic Gene Expression Becomes Advantageous

    KAUST Repository

    Matsumoto, Tomotaka

    2015-11-24

    Recent studies suggest the existence of a stochasticity in gene expression (SGE) in many organisms, and its non-negligible effect on their phenotype and fitness. To date, however, how SGE affects the key parameters of population genetics are not well understood. SGE can increase the phenotypic variation and act as a load for individuals, if they are at the adaptive optimum in a stable environment. On the other hand, part of the phenotypic variation caused by SGE might become advantageous if individuals at the adaptive optimum become genetically less-adaptive, for example due to an environmental change. Furthermore, SGE of unimportant genes might have little or no fitness consequences. Thus, SGE can be advantageous, disadvantageous, or selectively neutral depending on its context. In addition, there might be a genetic basis that regulates magnitude of SGE, which is often referred to as “modifier genes,” but little is known about the conditions under which such an SGE-modifier gene evolves. In the present study, we conducted individual-based computer simulations to examine these conditions in a diploid model. In the simulations, we considered a single locus that determines organismal fitness for simplicity, and that SGE on the locus creates fitness variation in a stochastic manner. We also considered another locus that modifies the magnitude of SGE. Our results suggested that SGE was always deleterious in stable environments and increased the fixation probability of deleterious mutations in this model. Even under frequently changing environmental conditions, only very strong natural selection made SGE adaptive. These results suggest that the evolution of SGE-modifier genes requires strict balance among the strength of natural selection, magnitude of SGE, and frequency of environmental changes. However, the degree of dominance affected the condition under which SGE becomes advantageous, indicating a better opportunity for the evolution of SGE in different genetic

  11. Development of a shortleaf pine individual-tree growth equation using non-linear mixed modeling techniques

    Science.gov (United States)

    Chakra B. Budhathoki; Thomas B. Lynch; James M. Guldin

    2010-01-01

    Nonlinear mixed-modeling methods were used to estimate parameters in an individual-tree basal area growth model for shortleaf pine (Pinus echinata Mill.). Shortleaf pine individual-tree growth data were available from over 200 permanently established 0.2-acre fixed-radius plots located in naturally-occurring even-aged shortleaf pine forests on the...

  12. The Importance of Tree Height in Estimating Individual Tree Biomass While Considering Errors in Measurements and Allometric Models

    OpenAIRE

    Phalla, Thuch; Ota, Tetsuji; Mizoue, Nobuya; Kajisa, Tsuyoshi; Yoshida, Shigejiro; Vuthy, Ma; Heng, Sokh

    2018-01-01

    This study evaluated the uncertainty of individual tree biomass estimated by allometric models by both including and excluding tree height independently. Using two independent sets of measurements on the same trees, the errors in the measurement of diameter at breast height and tree height were quantified, and the uncertainty of individual tree biomass estimation caused by errors in measurement was calculated. For both allometric models, the uncertainties of the individual tree biomass estima...

  13. Tundra shrubification and tree-line advance amplify arctic climate warming: results from an individual-based dynamic vegetation model

    International Nuclear Information System (INIS)

    Zhang Wenxin; Miller, Paul A; Smith, Benjamin; Wania, Rita; Koenigk, Torben; Döscher, Ralf

    2013-01-01

    One major challenge to the improvement of regional climate scenarios for the northern high latitudes is to understand land surface feedbacks associated with vegetation shifts and ecosystem biogeochemical cycling. We employed a customized, Arctic version of the individual-based dynamic vegetation model LPJ-GUESS to simulate the dynamics of upland and wetland ecosystems under a regional climate model–downscaled future climate projection for the Arctic and Subarctic. The simulated vegetation distribution (1961–1990) agreed well with a composite map of actual arctic vegetation. In the future (2051–2080), a poleward advance of the forest–tundra boundary, an expansion of tall shrub tundra, and a dominance shift from deciduous to evergreen boreal conifer forest over northern Eurasia were simulated. Ecosystems continued to sink carbon for the next few decades, although the size of these sinks diminished by the late 21st century. Hot spots of increased CH 4 emission were identified in the peatlands near Hudson Bay and western Siberia. In terms of their net impact on regional climate forcing, positive feedbacks associated with the negative effects of tree-line, shrub cover and forest phenology changes on snow-season albedo, as well as the larger sources of CH 4 , may potentially dominate over negative feedbacks due to increased carbon sequestration and increased latent heat flux. (letter)

  14. Parameter Scaling for Epidemic Size in a Spatial Epidemic Model with Mobile Individuals.

    Directory of Open Access Journals (Sweden)

    Chiyori T Urabe

    Full Text Available In recent years, serious infectious diseases tend to transcend national borders and widely spread in a global scale. The incidence and prevalence of epidemics are highly influenced not only by pathogen-dependent disease characteristics such as the force of infection, the latent period, and the infectious period, but also by human mobility and contact patterns. However, the effect of heterogeneous mobility of individuals on epidemic outcomes is not fully understood. Here, we aim to elucidate how spatial mobility of individuals contributes to the final epidemic size in a spatial susceptible-exposed-infectious-recovered (SEIR model with mobile individuals in a square lattice. After illustrating the interplay between the mobility parameters and the other parameters on the spatial epidemic spreading, we propose an index as a function of system parameters, which largely governs the final epidemic size. The main contribution of this study is to show that the proposed index is useful for estimating how parameter scaling affects the final epidemic size. To demonstrate the effectiveness of the proposed index, we show that there is a positive correlation between the proposed index computed with the real data of human airline travels and the actual number of positive incident cases of influenza B in the entire world, implying that the growing incidence of influenza B is attributed to increased human mobility.

  15. Determinants of functioning and well-being among individuals with schizophrenia: An integrated model

    Science.gov (United States)

    Yanos, P.T.; Moos, R.H.

    2006-01-01

    Outcomes for health conditions are typically the result of multiple factors; however, studies tend to focus on a narrow class of variables. Functioning and well-being outcomes for schizophrenia are diverse and have resisted simple explanation; however, prior research has not offered an integrated understanding of the relative contributions of enduring and episodic environmental factors, personal resources and psychiatric factors, and cognitive appraisal and coping, on functioning and well-being outcomes in schizophrenia. The present article sets out an integrated model of the determinants of functioning and well-being among individuals with schizophrenia. To examine evidence that bears on the model, literature on hypothesized relationships is reviewed to identify areas for which there is strong evidence and areas where more research is needed. The article suggests areas for further research, and directs researchers and practitioners toward areas of intervention that can enhance functioning and well-being for persons diagnosed with schizophrenia. PMID:16480804

  16. DISPLACE: a dynamic, individual-based model for spatial fishing planning and effort displacement: Integrating underlying fish population models

    DEFF Research Database (Denmark)

    Bastardie, Francois; Nielsen, J. Rasmus; Miethe, Tanja

    or to the alteration of individual fishing patterns. We demonstrate that integrating the spatial activity of vessels and local fish stock abundance dynamics allow for interactions and more realistic predictions of fishermen behaviour, revenues and stock abundance......We previously developed a spatially explicit, individual-based model (IBM) evaluating the bio-economic efficiency of fishing vessel movements between regions according to the catching and targeting of different species based on the most recent high resolution spatial fishery data. The main purpose...... was to test the effects of alternative fishing effort allocation scenarios related to fuel consumption, energy efficiency (value per litre of fuel), sustainable fish stock harvesting, and profitability of the fisheries. The assumption here was constant underlying resource availability. Now, an advanced...

  17. Evaluation of an e-PBL model to promote individual reasoning.

    Science.gov (United States)

    Kim, Kyong-Jee; Kee, Changwon

    2013-01-01

    Medical educators should promote the development of student clinical reasoning toward independence in clinical settings. The objective of this study was to evaluate an online problem-based learning (e-PBL) model designed to promote student individual reasoning in supplement to traditional PBL. Twelve e-PBL modules were added to the fully problem-based curriculum for Year 2 at Sungkyunkwan University School of Medicine (SKKUSOM). In this e-PBL, students worked on the problems individually in an online setting, followed by face-to-face discussions in a colloquium. The cases were presented using interactive multimedia to enhance the authenticity of the case and stimulate student interest in learning. A formative evaluation study was conducted to determine student satisfaction with e-PBL and its effectiveness as perceived by the students using both quantitative and qualitative methods. A cohort of Year 2 students at SKKUSOM (n = 38) took part in this study. Students perceived e-PBL significantly more positively after they had taken a module in terms of its ability to foster problem-solving skills and its ability to allow them to learn in ways suited to individual learning styles. Additionally, student survey and interview revealed that a vast majority of students were satisfied with the overall learning process in e-PBL and perceived it positively in fostering knowledge acquisition and clinical reasoning. Moreover, students found the cases realistic and engaging. The results show the potential of e-PBL to enhance traditional PBL by promoting the development of individual reasoning in a flexible online-learning environment and offering cases in an interactive multimedia format, which warrants further investigation into its impact on student learning outcomes.

  18. Statistics and Stochastic Models of an Individual Motion of Photosensitive Alga Euglena gracilis

    Science.gov (United States)

    Ogawa, Takuma; Izumi, Shunsuke; Iima, Makoto

    2017-07-01

    The motion of individual Euglena gracilis was experimentally analyzed. The flow field of E. gracilis during free swimming was visualized by the particle image velocimetry method to show that the time-averaged flow field is well represented by two Stokeslets, suggesting that the flow around E. gracilis is categorized as the typical puller type. The orbit of swimming E. gracilis in a uniform environment was also analyzed. The orbit was classified into two modes, "moving" and "stationary", to obtain statistics on waiting time, swimming length during a single motion, and the directional change between two successive swimming directions. For the distribution of waiting time and swimming length, power laws were obtained. On the basis of the results, biased random walk models were constructed to discuss the long-time diffusion behavior of an individual motion. The swimming behavior of E. gracilis in a nonuniform light environment was analyzed by focusing on the directional change behavior, whereby a Markov chain model was proposed to reproduce the observed behavior.

  19. Profit-Based Model Selection for Customer Retention Using Individual Customer Lifetime Values.

    Science.gov (United States)

    Óskarsdóttir, María; Baesens, Bart; Vanthienen, Jan

    2018-03-01

    The goal of customer retention campaigns, by design, is to add value and enhance the operational efficiency of businesses. For organizations that strive to retain their customers in saturated, and sometimes fast moving, markets such as the telecommunication and banking industries, implementing customer churn prediction models that perform well and in accordance with the business goals is vital. The expected maximum profit (EMP) measure is tailored toward this problem by taking into account the costs and benefits of a retention campaign and estimating its worth for the organization. Unfortunately, the measure assumes fixed and equal customer lifetime value (CLV) for all customers, which has been shown to not correspond well with reality. In this article, we extend the EMP measure to take into account the variability in the lifetime values of customers, thereby basing it on individual characteristics. We demonstrate how to incorporate the heterogeneity of CLVs when CLVs are known, when their prior distribution is known, and when neither is known. By taking into account individual CLVs, our proposed approach of measuring model performance gives novel insights when deciding on a customer retention campaign. The method is dependent on the characteristics of the customer base as is compliant with modern business analytics and accommodates the data-driven culture that has manifested itself within organizations.

  20. [Digital modeling for the individual mandibular 3D mesh scaffold based on 3D printing technology].

    Science.gov (United States)

    Yan, Rongzeng; Luo, Danmei; Qin, Xiaoyu; Li, Runxin; Rong, Qiguo; Hu, Min

    2016-05-01

    To investigate an ideal modeling method of designing 3D mesh scaffold substitutes based on tissue engineering to restore mandibular bone defects. By analyzing the theoretical model from titanium scaffolds fabricated by 3D printing, the feasibility and effectiveness of the proposed methodology were verified. Based on the CT scanned data of a subject, the Mimics 15.0 and Geomagic studio 12.0 reverse engineering software were adopted to generate surface model of mandibular bone and the defect area was separated from the 3D model of bone. Then prosthesis was designed via mirror algorithm, in which outer shape was used as the external shape of scaffold. Unigraphics software NX 8.5 was applied on Boolean calculation of subtraction between prosthesis and regular microstructure structure and ANSYS 14.0 software was used to design the inner construction of 3D mesh scaffolds. The topological structure and the geometrical parameters of 3D mesh titanium scaffolds were adjusted according to the aim of optimized structure and maximal strength with minimal weight. The 3D mesh scaffolds solid model through two kinds of computer-aided methods was input into 3D printing equipment to fabricate titanium scaffolds. Individual scaffolds were designed successfully by two modeling methods. The finite element optimization made 10% decrease of the stress peak and volume decrease of 43%, and the porosity increased to 76.32%. This modeling method was validated by 3D printing titanium scaffold to be feasible and effective. 3D printing technology combined with finite element topology optimization to obtain the ideal mandibular 3D mesh scaffold is feasible and effective.

  1. The Employment of spatial autoregressive models in predicting demand for natural gas; O Emprego de modelos auto-regressivos espaciais na previsao de demanda para gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Jorge Henrique de [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Silva, Alexandre Pinto Alves da [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Eletrica

    2010-07-01

    Develop the natural gas network is critical success factor for the distribution company. It is a decision that employs the demand given location 'x' and a future time 't' so that the net allows the best conditions for the return of the capital. In this segment, typical network industry, the spatial infra-structure vision associated to the market allows better evaluation of the business because to mitigate costs and risks. In fact, economic models little developed in order to assess the question of the location, due to its little employment by economists. The objective of this article is to analyze the application of spatial perspective in natural gas demand forecasting and to identify the models that can be employed observing issues of dependency and spatial heterogeneity; as well as the capacity of mapping of variables associated with the problem. (author)

  2. Attempted development and cross-validation of predictive models of individual-level and organizational-level turnover of nuclear power operators

    International Nuclear Information System (INIS)

    Vasa-Sideris, S.J.

    1989-01-01

    Nuclear power accounts for 209% of the electric power generated in the U.S. by 107 nuclear plants which employ over 8,700 operators. Operator turnover is significant to utilities from the economic point of view since it costs almost three hundred thousand dollars to train and qualify one operator, and because turnover affects plant operability and therefore plant safety. The study purpose was to develop and cross-validate individual-level and organizational-level models of turnover of nuclear power plant operators. Data were obtained by questionnaires and from published data for 1983 and 1984 on a number of individual, organizational, and environmental predictors. Plants had been in operation for two or more years. Questionnaires were returned by 29 out of 50 plants on over 1600 operators. The objectives were to examine the reliability of the turnover criterion, to determine the classification accuracy of the multivariate predictive models and of categories of predictors (individual, organizational, and environmental) and to determine if a homology existed between the individual-level and organizational-level models. The method was to examine the shrinkage that occurred between foldback design (in which the predictive models were reapplied to the data used to develop them) and cross-validation. Results did not support the hypothesis objectives. Turnover data were accurate but not stable between the two years. No significant differences were detected between the low and high turnover groups at the organization or individual level in cross-validation. Lack of stability in the criterion, restriction of range, and small sample size at the organizational level were serious limitations of this study. The results did support the methods. Considerable shrinkage occurred between foldback and cross-validation of the models

  3. Modelling southern elephant seals Mirounga leonina using an individual-based model coupled with a dynamic energy budget.

    Science.gov (United States)

    Goedegebuure, Merel; Melbourne-Thomas, Jessica; Corney, Stuart P; McMahon, Clive R; Hindell, Mark A

    2018-01-01

    Higher trophic-level species are an integral component of any marine ecosystem. Despite their importance, methods for representing these species in end-to-end ecosystem models often have limited representation of life histories, energetics and behaviour. We built an individual-based model coupled with a dynamic energy budget for female southern elephant seals Mirounga leonina to demonstrate a method for detailed representation of marine mammals. We aimed to develop a model which could i) simulate energy use and life histories, as well as breeding traits of southern elephant seals in an emergent manner, ii) project a stable population over time, and iii) have realistic population dynamics and structure based on emergent life history features (such as age at first breeding, lifespan, fecundity and (yearling) survival). We evaluated the model's ability to represent a stable population over long time periods (>10 generations), including the sensitivity of the emergent properties to variations in key parameters. Analyses indicated that the model is sensitive to changes in resource availability and energy requirements for the transition from pup to juvenile, and juvenile to adult stage. This was particularly the case for breeding success and yearling survival. This model is suitable for use as a standalone tool for investigating the impacts of changes to behaviour and population responses of southern elephant seals.

  4. [Illegal migrants and sanctions against employers in the United States: the anti-model of state laws].

    Science.gov (United States)

    Ardittis, S

    1984-06-01

    This study attempts to demonstrate the various reasons why sanctions against employers of illegal migrants have never been effectively enforced in the 11 US states and 1 city that have passed such legislation, and to assess the factors involved in the ineffectiveness of state laws: the lack of resources and experience for enforcement, and the exclusively local authority of the laws. Some of the state laws refer only to the legal residence of the migrants while others pertain to the lack of work permits. In all jurisdictions only 5 cases have been brought as a result of the laws. The ostensible reasons for the failure of the laws include uncertainties about proof of the employer's knowledge of the immigrants' legal status and uncertainties related to the primacy of federal legislation covering migrants and the lack of specific provisions covering employment within such legislation. The deeper reasons for the failure of such laws result from absolute opposition to them by civil rights activists and minority groups, especially hispanics, on the 1 hand, and on the other by the economic groups most directly affected, which are primarily the traditional employers of illegal workers. It must be asked whether the major problem resulting from non-application of the laws is the lack of results obtained by the states or the absence of experience that could guide impending federal legislation by indicating the results of sanctions against employers on the rate of irregular migration or whether a substantial reduction in the number of illegal workers in the secondary sector of the economy results in a greater employment of lower level native workers.

  5. Modelling the propagation of effects of chronic exposure to ionising radiation from individuals to populations

    Energy Technology Data Exchange (ETDEWEB)

    Alonzo, F. [Laboratory of Environmental Modelling, DEI/SECRE/LME, Institute of Radioprotection and Nuclear Safety (IRSN), Cadarache, Building 159, BP3, 13115 St-Paul-lez-Durance Cedex (France); Laboratory of Radioecology and Ecotoxicology, DEI/SECRE/LRE, Institute of Radioprotection and Nuclear Safety (IRSN), Cadarache Building 186, BP3, 13115 St-Paul-lez-Durance Cedex (France)], E-mail: frederic.alonzo@irsn.fr; Hertel-Aas, T. [Department of Plant and Environmental Sciences, P.O. Box 5003, Norwegian University of Life Sciences, 1432 Aas (Norway); Gilek, M. [School of Life Sciences, Soedertoern University College, 14189 Huddinge (Sweden); Gilbin, R. [Laboratory of Radioecology and Ecotoxicology, DEI/SECRE/LRE, Institute of Radioprotection and Nuclear Safety (IRSN), Cadarache Building 186, BP3, 13115 St-Paul-lez-Durance Cedex (France); Oughton, D.H. [Department of Plant and Environmental Sciences, P.O. Box 5003, Norwegian University of Life Sciences, 1432 Aas (Norway); Garnier-Laplace, J. [Laboratory of Radioecology and Ecotoxicology, DEI/SECRE/LRE, Institute of Radioprotection and Nuclear Safety (IRSN), Cadarache Building 186, BP3, 13115 St-Paul-lez-Durance Cedex (France)

    2008-09-15

    This study evaluated the potential effect of ionising radiation on population growth using simple population models and parameter values derived from chronic exposure experiments in two invertebrate species with contrasting life-history strategies. In the earthworm Eisenia fetida, models predicted increasing delay in population growth with increasing gamma dose rate (up to 0.6 generation times at 11 mGy h{sup -1}). Population extinction was predicted at 43 mGy h{sup -1}. In the microcrustacean Daphnia magna, models predicted increasing delay in population growth with increasing alpha dose rate (up to 0.8 generation times at 15.0 mGy h{sup -1}), only after two successive generations were exposed. The study examined population effects of changes in different individual endpoints (including survival, number of offspring produced and time to first reproduction). Models showed that the two species did not respond equally to equivalent levels of change, the fast growing daphnids being more susceptible to reduction in fecundity or delay in reproduction than the slow growing earthworms. This suggested that susceptibility of a population to ionising radiation cannot be considered independent of the species' life history.

  6. Dynamic modeling of vaccinating behavior as a function of individual beliefs.

    Directory of Open Access Journals (Sweden)

    Flávio Codeço Coelho

    2009-07-01

    Full Text Available Individual perception of vaccine safety is an important factor in determining a person's adherence to a vaccination program and its consequences for disease control. This perception, or belief, about the safety of a given vaccine is not a static parameter but a variable subject to environmental influence. To complicate matters, perception of risk (or safety does not correspond to actual risk. In this paper we propose a way to include the dynamics of such beliefs into a realistic epidemiological model, yielding a more complete depiction of the mechanisms underlying the unraveling of vaccination campaigns. The methodology proposed is based on Bayesian inference and can be extended to model more complex belief systems associated with decision models. We found the method is able to produce behaviors which approximate what has been observed in real vaccine and disease scare situations. The framework presented comprises a set of useful tools for an adequate quantitative representation of a common yet complex public-health issue. These tools include representation of beliefs as Bayesian probabilities, usage of logarithmic pooling to combine probability distributions representing opinions, and usage of natural conjugate priors to efficiently compute the Bayesian posterior. This approach allowed a comprehensive treatment of the uncertainty regarding vaccination behavior in a realistic epidemiological model.

  7. Views of the employers

    International Nuclear Information System (INIS)

    Ishida, J.

    2003-01-01

    The employer shall establish and maintain a safety management system, which is a part of the overall management system that facilitates the management of the occupational health and safety risks associated with the business of the organization. In addition to meeting its legal responsibilities, the employer should aim to improve its occupational health and safety performance, and its safety management system, effectively and efficiently, to meet changing business and regulatory needs. Occupational radiation protection is also a part of its activities. The concept of 'as low as reasonably achievable' (ALARA) presumes that any increment of radiation dose may produce a proportionate incremental risk, and that all radiation doses shall be kept ALARA, taking into account social and economic factors. Up to now, by implementing various activities in accordance with the principle of ALARA, employers have been minimizing the exposure dose of plant workers. Owing to improvements in hardware and administrative control, the exposure dose of workers has followed a remarkable downward trend, and now the number of workers exceeding 20 mSv/a is nearly zero. By implementing more thorough radiation protection and safety programmes, as well as by promoting safety consciousness among individual workers, the employers are continuing their efforts, respecting ALARA, to prevent workers from being exposed to radiation unnecessarily. As a consequence, the average individual dose of workers has dropped to 1 mSv/a or so. There may no longer be a discernible decrease in doses received at most of nuclear facilities

  8. Population modelling to compare chronic external radiotoxicity between individual and population endpoints in four taxonomic groups

    International Nuclear Information System (INIS)

    Alonzo, Frédéric; Hertel-Aas, Turid; Real, Almudena; Lance, Emilie; Garcia-Sanchez, Laurent; Bradshaw, Clare; Vives i Batlle, Jordi; Oughton, Deborah H.; Garnier-Laplace, Jacqueline

    2016-01-01

    In this study, we modelled population responses to chronic external gamma radiation in 12 laboratory species (including aquatic and soil invertebrates, fish and terrestrial mammals). Our aim was to compare radiosensitivity between individual and population endpoints and to examine how internationally proposed benchmarks for environmental radioprotection protected species against various risks at the population level. To do so, we used population matrix models, combining life history and chronic radiotoxicity data (derived from laboratory experiments and described in the literature and the FREDERICA database) to simulate changes in population endpoints (net reproductive rate R 0 , asymptotic population growth rate λ, equilibrium population size N eq ) for a range of dose rates. Elasticity analyses of models showed that population responses differed depending on the affected individual endpoint (juvenile or adult survival, delay in maturity or reduction in fecundity), the considered population endpoint (R 0 , λ or N eq ) and the life history of the studied species. Among population endpoints, net reproductive rate R 0 showed the lowest EDR 10 (effective dose rate inducing 10% effect) in all species, with values ranging from 26 μGy h −1 in the mouse Mus musculus to 38,000 μGy h −1 in the fish Oryzias latipes. For several species, EDR 10 for population endpoints were lower than the lowest EDR 10 for individual endpoints. Various population level risks, differing in severity for the population, were investigated. Population extinction (predicted when radiation effects caused population growth rate λ to decrease below 1, indicating that no population growth in the long term) was predicted for dose rates ranging from 2700 μGy h −1 in fish to 12,000 μGy h −1 in soil invertebrates. A milder risk, that population growth rate λ will be reduced by 10% of the reduction causing extinction, was predicted for dose rates ranging from 24 μGy h −1 in

  9. Modeling variability in air pollution-related health damages from individual airport emissions.

    Science.gov (United States)

    Penn, Stefani L; Boone, Scott T; Harvey, Brian C; Heiger-Bernays, Wendy; Tripodis, Yorghos; Arunachalam, Sarav; Levy, Jonathan I

    2017-07-01

    In this study, we modeled concentrations of fine particulate matter (PM 2.5 ) and ozone (O 3 ) attributable to precursor emissions from individual airports in the United States, developing airport-specific health damage functions (deaths per 1000t of precursor emissions) and physically-interpretable regression models to explain variability in these functions. We applied the Community Multiscale Air Quality model using the Decoupled Direct Method to isolate PM 2.5 - or O 3 -related contributions from precursor pollutants emitted by 66 individual airports. We linked airport- and pollutant-specific concentrations with population data and literature-based concentration-response functions to create health damage functions. Deaths per 1000t of primary PM 2.5 emissions ranged from 3 to 160 across airports, with variability explained by population patterns within 500km of the airport. Deaths per 1000t of precursors for secondary PM 2.5 varied across airports from 0.1 to 2.7 for NOx, 0.06 to 2.9 for SO 2 , and 0.06 to 11 for VOCs, with variability explained by population patterns and ambient concentrations influencing particle formation. Deaths per 1000t of O 3 precursors ranged from -0.004 to 1.0 for NOx and 0.03 to 1.5 for VOCs, with strong seasonality and influence of ambient concentrations. Our findings reinforce the importance of location- and source-specific health damage functions in design of health-maximizing emissions control policies. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Oslo traffic study - part 2: quantifying effects of traffic measures using individual exposure modeling

    International Nuclear Information System (INIS)

    Clench-Aas, J.; Bartonova, A.; Klaeboe, R.; Kolbenstvedt, M.

    2000-01-01

    In quantifying the benefits of air pollution reduction measures, it is desirable to compare the size of the benefits with the effects of other individual confounding factors such as smoking or passive smoking. The effect of pollution is rarely very large and in order to quantify it, exposure estimating procedures must be as accurate as possible. Dispersion models, run for hourly time intervals and controlled by measurements, are therefore used to provide estimates for specific receptor points. Results of three consecutive cross-sectional investigations in an area of Oslo characterized by heavy traffic are presented. The study was designed to provide repeated information on the effects of traffic diversion measures on the self-reporting of symptoms of reduced health of 1100 adults living in Oslo. The principal source of air pollution in Oslo is vehicular traffic. The primary pollutants of interest are nitrogen dioxide (NO 2 ) and respirable particles (PM 2.5 and PM 10 ). The mean hourly concentration of exposure was estimated at each participant's home by means of a time-dependent finite dispersion model combined with subgrid models to describe the source contribution to the grid concentrations. The study controlled the confounding factors. Using the symptom fatigue, the study illustrates that by controlling the changes in population composition, estimated exposure-effect relationships for health symptoms allow the effect of the studied traffic measures on the population to be evaluated. Since the method is based on individual estimates of exposure to different pollutants, it allows standardizing the exposure to compare effects of different pollutants. The study offers a methodology that is useful in evaluating the benefits of measures by both being able to quantify and compare the effects of different compounds and effects on different population sub-groups. (author)

  11. Impulsive vaccination and dispersal on dynamics of an SIR epidemic model with restricting infected individuals boarding transports

    Science.gov (United States)

    Jiao, Jianjun; Cai, Shaohong; Li, Limei

    2016-05-01

    To understand the effect of impulsive vaccination and restricting infected individuals boarding transports on disease spread, we establish an SIR model with impulsive vaccination, impulsive dispersal and restricting infected individuals boarding transports. This SIR epidemic model for two regions, which are connected by transportation of non-infected individuals, portrays the evolvement of diseases. We prove that all solutions of the investigated system are uniformly ultimately bounded. We also prove that there exists globally asymptotically stable infection-free boundary periodic solution. The condition for permanence is discussed. It is concluded that the approach of impulsive vaccination and restricting infected individuals boarding transports provides reliable tactic basis for preventing disease spread.

  12. Preparing At-Risk Youth for a Changing World: Revisiting a Person-in-Context Model for Transition to Employment

    Science.gov (United States)

    DeLuca, Christopher; Godden, Lorraine; Hutchinson, Nancy L.; Versnel, Joan

    2015-01-01

    Background: The current global cohort of youth has been called "a generation at-risk", marked by a dramatic rise in youth who are not in employment, education or training programmes. In 2010, youth were three times as likely as adults to be unemployed, with youth unemployment worsening in 2012 and 2013. Accordingly, there is an urgent…

  13. Combining Quality Work-Integrated Learning and Career Development Learning through the Use of the SOAR Model to Enhance Employability

    Science.gov (United States)

    Reddan, Gregory; Rauchle, Maja

    2017-01-01

    This paper presents students' perceptions of the benefits to employability of a suite of courses that incorporate both work-integrated learning (WIL) and career development learning (CDL). Field Project A and Field Project B are elective courses in the Bachelor of Exercise Science at Griffith University. These courses engage students in active and…

  14. Targeted drug delivery by gemtuzumab ozogamicin: mechanism-based mathematical model for treatment strategy improvement and therapy individualization.

    Directory of Open Access Journals (Sweden)

    Eva Jager

    Full Text Available Gemtuzumab ozogamicin (GO is a chemotherapy-conjugated anti-CD33 monoclonal antibody effective in some patients with acute myeloid leukemia (AML. The optimal treatment schedule and optimal timing of GO administration relative to other agents remains unknown. Conventional pharmacokinetic analysis has been of limited insight for the schedule optimization. We developed a mechanism-based mathematical model and employed it to analyze the time-course of free and GO-bound CD33 molecules on the lekemic blasts in individual AML patients treated with GO. We calculated expected intravascular drug exposure (I-AUC as a surrogate marker for the response to the drug. A high CD33 production rate and low drug efflux were the most important determinants of high I-AUC, characterizing patients with favorable pharmacokinetic profile and, hence, improved response. I-AUC was insensitive to other studied parameters within biologically relevant ranges, including internalization rate and dissociation constant. Our computations suggested that even moderate blast burden reduction prior to drug administration enables lowering of GO doses without significantly compromising intracellular drug exposure. These findings indicate that GO may optimally be used after cyto-reductive chemotherapy, rather than before, or concomitantly with it, and that GO efficacy can be maintained by dose reduction to 6 mg/m(2 and a dosing interval of 7 days. Model predictions are validated by comparison with the results of EORTC-GIMEMA AML19 clinical trial, where two different GO schedules were administered. We suggest that incorporation of our results in clinical practice can serve identification of the subpopulation of elderly patients who can benefit most of the GO treatment and enable return of the currently suspended drug to clinic.

  15. Error propagation models to examine the effects of geocoding quality on spatial analysis of individual-level datasets.

    Science.gov (United States)

    Zandbergen, P A; Hart, T C; Lenzer, K E; Camponovo, M E

    2012-04-01

    The quality of geocoding has received substantial attention in recent years. A synthesis of published studies shows that the positional errors of street geocoding are somewhat unique relative to those of other types of spatial data: (1) the magnitude of error varies strongly across urban-rural gradients; (2) the direction of error is not uniform, but strongly associated with the properties of local street segments; (3) the distribution of errors does not follow a normal distribution, but is highly skewed and characterized by a substantial number of very large error values; and (4) the magnitude of error is spatially autocorrelated and is related to properties of the reference data. This makes it difficult to employ analytic approaches or Monte Carlo simulations for error propagation modeling because these rely on generalized statistical characteristics. The current paper describes an alternative empirical approach to error propagation modeling for geocoded data and illustrates its implementation using three different case-studies of geocoded individual-level datasets. The first case-study consists of determining the land cover categories associated with geocoded addresses using a point-in-raster overlay. The second case-study consists of a local hotspot characterization using kernel density analysis of geocoded addresses. The third case-study consists of a spatial data aggregation using enumeration areas of varying spatial resolution. For each case-study a high quality reference scenario based on address points forms the basis for the analysis, which is then compared to the result of various street geocoding techniques. Results show that the unique nature of the positional error of street geocoding introduces substantial noise in the result of spatial analysis, including a substantial amount of bias for some analysis scenarios. This confirms findings from earlier studies, but expands these to a wider range of analytical techniques. Copyright © 2012 Elsevier Ltd

  16. Environmental and Individual Determinants of Female Entrepreneurship in Algeria: Applying the Structural Equation Modeling

    Directory of Open Access Journals (Sweden)

    Abderrezzak BENHABIB

    2014-03-01

    Full Text Available On the basis of the seminal work of Fishbein and Ajzen (1975, we try  to clarify  how  individual  and  environment  factors  influence  the students’  attitudes towards Entrepreneurship and Entrepreneurial Intention. After a short review of literature, we present the results of an empirical study conducted among a sample of 290 final year students by using a structural  equation  modeling  validated  through  the  use  of  a  two-stage  analysis  of Anderson  and  Gerbing  (1988  and  a  factorial  confirmatory  analysis  and  a measurement adjustment (Hair et al.1998. Attitude driven from individual variables is negative while that derived from environmental  variables  is  positive.  Our  results  show  furthermore,  that  the  role  of media and institutions is still Limited and needs redeployment. Woman is now recognized as one of the  sources of  economic  growth  (Arasti  2008.  Although  female  entrepreneurship  is  attracting more and more researchers, it is still considered as an understudied field of research (De Bruin et al.2006, 2007; Brush, De Bruin, & Welter, 2009. Research  on  female  entrepreneurship  has  intensified since  the  early  80s,  but  few  have  explored  the  influence  of  environmental  and individual factors related to female entrepreneurship.

  17. Individual taper models for natural cedar and Taurus fir mixed stands of Bucak Region, Turkey

    Directory of Open Access Journals (Sweden)

    Ramazan Özçelik

    2017-11-01

    Full Text Available In this study, we assessed the performance of different types of taper equations for predicting tree diameters at specific heights and total stem volumes for mixed stands of Taurus cedar (Cedrus libani A. Rich. and Taurus fir (Abies cilicica Carr.. We used data from mixed stands containing a total of 131 cedar and 124 Taurus fir trees. We evaluated six commonly used and well-known forestry taper functions developed by a variety of researchers (Biging (1984, Zakrzewski (1999, Muhairwe (1999, Fang et al. (2000, Kozak (2004, and Sharma and Zhang (2004. To address problems related to autocorrelation and multicollinearity in the hierarchical data associated with the construction of taper models, we used appropriate statistical procedures for the model fitting. We compared model performances based on the analysis of three goodness-of-fit statistics and found the compatible segmented model of Fang et al. (2000 to be superior in describing the stem profile and stem volume of both tree species in mixed stands. The equation used by Zakrzewski (1999 exhibited the poorest fitting results of the three taper equations. In general, we found segmented taper equations to provide more accurate predictions than variable-form models for both tree species. Results from the non-linear extra sum of squares method indicate that stem tapers differ among tree species in mixed stands. Therefore, a different taper function should be used for each tree species in mixed stands in the Bucak district. Using individual-specific taper equations yields more robust estimations and, therefore, will enhance the prediction accuracy of diameters at different heights and volumes in mixed stands.

  18. Joint modelling of longitudinal 3MS scores and the risk of mortality among cognitively impaired individuals.

    Directory of Open Access Journals (Sweden)

    Chris B Guure

    Full Text Available Modified Mini-Mental State Examination (3MS is an instrument administered by trained personnel to examine levels of participants' cognitive function. However, the association between changes in scores over time and the risk of death (mortality is not known. The aims of this study are to examine the association between 3MS scores and mortality via cognitive impairment among older women and to determine individuals' risk of changes in scores to better predict their survival and mortality rates.We propose a Bayesian joint modelling approach to determine mortality due to cognitive impairment via repeated measures of 3MS scores trajectories over a 21-year follow-up period. Data for this study are taken from the Osteoporotic Fracture longitudinal study among women aged 65+ which started in 1986-88.The standard relative risk model from the analyses with a baseline 3MS score after adjusting for all the significant covariates demonstrates that, every unit decrease in a 3MS score corresponds to a non-significant 1.059 increase risk of mortality with a 95% CI of (0.981, 1.143, while the extended model results in a significant 0.09% increased risk in mortality. The joint modelling approach found a strong association between the 3MS scores and the risk of mortality, such that, every unit decrease in 3MS scores results in a 1.135 (13% increased risk of death via cognitive impairment with a 95% CI of (1.056, 1.215.It has been demonstrated that a decrease in 3MS results has a significant increase risk of mortality due to cognitive impairment via joint modelling, but insignificant when considered under the standard relative risk approach.

  19. MENGATASI MASALAH LOW SELF ESTEEM SISWA MELALUI KONSELING INDIVIDU MODEL PERSON CENTERED THERAPHY

    Directory of Open Access Journals (Sweden)

    Azmi Hanifah

    2017-03-01

    Full Text Available This research applied based on the phenomenon in SMPN 25 Semarang which indicates several students who have low self-esteem, through the results of the DCM’s analysis distributed to the students of 9th grade. This research used to show the students’ self-esteem before and after having individual counseling model of person-centered Therapy and whether the model of person-centered Therapy counseling can overcome the problem of low self-esteem students. This research design is experimental research which using one group pretest-posttest design. The participants of this study were six students. The writer use Wilcoxon test as Hypothesis testing by comparing the level of the smallest of the pre and posttest. Obtained results Zcount 2,206 > Z table = 1.645, which means Ha accepted and Ho rejected. The research findings showed that (1 the pretest of the experiment of sixth counselees was 48.45% (2 In another hand the posttest result of the experiment sixth counselees was 75.65% (3 The problem of low self-esteem students can be solved through counseling models centered person theraphy. The result of the study shows that there is positive result and significant improvement of students’ self-esteem when teacher using Person Centered Therapy to solve low self-esteem problem.

  20. Model features as the basis of preparation of boxers individualization principal level (elite

    Directory of Open Access Journals (Sweden)

    O.J. Pavelec

    2013-10-01

    Full Text Available Purpose to improve the system of training boxers of higher categories (elite. Individualization of the training process using the model characteristics special physical preparedness. Materials : The study was conducted during 2000-2010. Participated boxers national team of Ukraine in the amount of 43 people. Of those honored masters of sport 6, masters of sports of international class 16, masters of sports 21. The average age of the athletes 23.5 years. Results : justified and features a specially designed model of physical fitness boxing class. It is established that the boxers middle weight classes (64 75 kg have an advantage over other boxers weight categories (light and after a hard in the development of speed and strength endurance. The presented model characteristics can guide the professional fitness boxing (elite, as representatives of the sport. Conclusions : It is established that the structure of the special physical training boxers depends on many components, such as weight category, tactical fighter role, skill level, stage of preparation.

  1. Active Aging for Individuals with Parkinson’s Disease: Definitions, Literature Review, and Models

    Directory of Open Access Journals (Sweden)

    Seyed-Mohammad Fereshtehnejad

    2014-01-01

    Full Text Available Active aging has been emerged to optimize different aspects of health opportunities during the aging process in order to enhance quality of life. Yet, most of the efforts are on normal aging and less attention has been paid for the elderly suffering from a chronic illness such as Parkinson’s disease (PD. The aim of this review was to investigate how the concept of “active aging” fit for the elderly with PD and to propose a new model for them using the recent improvements in caring models and management approaches. For this purpose, biomedical databases have been assessed using relevant keywords to find out appropriate articles. Movement problems of PD affect physical activity, psychiatric symptoms lessen social communication, and cognitive impairment could worsen mental well-being in elderly with PD, all of which could lead to earlier retirement and poorer quality of life compared with healthy elderly. Based on the multisystematic nature of PD, a new “Active Aging Model for Parkinson’s Disease” is proposed consisting of self-care, multidisciplinary and interdisciplinary care, palliative care, patient-centered care, and personalized care. These strategies could potentially help the individuals with PD to have a better management approach for their condition towards the concept of active aging.

  2. Active aging for individuals with Parkinson's disease: definitions, literature review, and models.

    Science.gov (United States)

    Fereshtehnejad, Seyed-Mohammad; Lökk, Johan

    2014-01-01

    Active aging has been emerged to optimize different aspects of health opportunities during the aging process in order to enhance quality of life. Yet, most of the efforts are on normal aging and less attention has been paid for the elderly suffering from a chronic illness such as Parkinson's disease (PD). The aim of this review was to investigate how the concept of "active aging" fit for the elderly with PD and to propose a new model for them using the recent improvements in caring models and management approaches. For this purpose, biomedical databases have been assessed using relevant keywords to find out appropriate articles. Movement problems of PD affect physical activity, psychiatric symptoms lessen social communication, and cognitive impairment could worsen mental well-being in elderly with PD, all of which could lead to earlier retirement and poorer quality of life compared with healthy elderly. Based on the multisystematic nature of PD, a new "Active Aging Model for Parkinson's Disease" is proposed consisting of self-care, multidisciplinary and interdisciplinary care, palliative care, patient-centered care, and personalized care. These strategies could potentially help the individuals with PD to have a better management approach for their condition towards the concept of active aging.

  3. Individualizing Management of Complex Esophageal Pathology Using Three-Dimensional Printed Models.

    Science.gov (United States)

    Dickinson, Karen J; Matsumoto, Jane; Cassivi, Stephen D; Reinersman, J Matthew; Fletcher, Joel G; Morris, Jonathan; Wong Kee Song, Louis M; Blackmon, Shanda H

    2015-08-01

    In complex esophageal cases, conventional two-dimensional imaging is limited in demonstrating anatomic relationships. We describe the utility of three-dimensional (3D) printed models for complex patients to individualize care. Oral effervescent agents, with positive enteric contrast, distended the esophagus during computed tomography (CT) scanning to facilitate segmentation during post-processing. The CT data were segmented, converted into a stereolithography file, and printed using photopolymer materials. In 1 patient with a left pneumonectomy, aortic bypass, and esophageal diversion, 3D printing enabled visualization of the native esophagus and facilitated endoscopic mucosal resection, followed by hiatal dissection and division of the gastroesophageal junction as treatment. In a second patient, 3D printing allowed enhanced visualization of multiple esophageal diverticula, allowing for optimization of the surgical approach. Printing of 3D anatomic models in patients with complex esophageal pathology facilitates planning the optimal surgical approach and anticipating potential difficulties for the multidisciplinary team. These models are invaluable for patient education. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  4. Studying Individual Differences in Predictability With Gamma Regression and Nonlinear Multilevel Models.

    Science.gov (United States)

    Culpepper, Steven Andrew

    2010-01-29

    Statistical prediction remains an important tool for decisions in a variety of disciplines. An equally important issue is identifying factors that contribute to more or less accurate predictions. The time series literature includes well developed methods for studying predictability and volatility over time. This article develops distribution-appropriate methods for studying individual differences in predictability for settings in psychological research. Specifically, 3 different approaches are discussed for modeling predictability. The 1st is a bivariate measure of predictability discussed previously in the psychology literature, the squared or absolute valued difference between criterion and predictor, which is shown to follow the gamma distribution. The 2nd method extended limitations of previous research and involved understanding predictability in regression models. The 3rd method used nonlinear multilevel models to study predictability in settings where participants are nested within clusters. An application was presented using SAS NLMIXED to understand the predictability of college grade point average by student demographic characteristics. The findings from the application suggest that the 1st-year college performance of English as a second language students were, on average, less predictable whereas females and Whites tended to demonstrate more predictable academic performance than their male or racial/ethnic minority counterparts.

  5. Numerical investigation of complete mandibular dentures stabilized by conventional or mini implants in patient individual models.

    Science.gov (United States)

    Lohmann, Anna; Keilig, Ludger; Heinemann, Friedhelm; Bourauel, Christoph; Hasan, Istabrak

    2018-02-08

    Poor stability of a complete denture is a common problem due to bone atrophy of the edentulous ridge. The aim of the present study was to analyze denture stability after receiving implants and to study the biomechanical properties of denture implants and the bone bed using conventional or mini implants. Five models based on computed tomography (CT) data of edentulous patients were created. The overdentures' connection to the implants was assured by means of ball head abutments and rubber rings. In three models, the denture was supported by two to four conventional implants and in two models, the overdenture was supported by three to five mini implants. The dentures were loaded according to the individual biting forces which was clinically measured by means of pressure sheets. After implantation, the biting forces and displacements of overdentures increased in comparison to complete dentures. Displacements and stresses were higher with mini implants than with conventional ones. Stress in the implants was markedly below the yield stress of titanium grade 5 (880 MPa). An increase in the stress in the bone around the implants was noticed as compared to the situation with complete dentures which was below the physiological range of bone loading (<4 MPa).

  6. An individual-based, spatial foraging model for cadmium accumulation in diving ducks

    Energy Technology Data Exchange (ETDEWEB)

    Lovvorn, J.R.; Gillingham, M.P. [Univ. of Wyoming, Laramie, WY (United States). Dept. of Zoology and Physiology

    1994-12-31

    Contaminant studies of migratory birds include two main approaches: (1) collecting wild birds and analyzing their tissues, and (2) toxicity assays with captive birds. The first approach has shortcomings for these highly mobile animals--one seldom knows their length of stay in the area, and sites are often in urban environments where shooting is problematic. The second approach with captive birds ignores changes in food intake with varying activity and weather experienced by wild birds, and greater toxic consequences under multiple environmental stresses. Neither of these approaches alone can predict maximum allowable contaminant levels in foods that preclude toxic effects under different field conditions, or what body burdens accumulate during varying lengths of stay and affect the birds` biology at other places and times. To allow such predictions, the authors developed an individual-based model for intake of benthic foods by diving ducks for varying weather, water depth, food dispersion, and nutrient content of food. Food-intake estimates are combined with laboratory data on contaminant uptake as a function of food consumption and contaminant content. As an example, the authors estimate cadmium uptake by canvas back ducks foraging on below ground tubers of the submerged plant Vallisneria americans. They then show how their model can be used to include avian benthiovores in aquatic food web models for ecological risk assessment.

  7. Individual and Familial Susceptibility to MPTP in a Common Marmoset Model for Parkinson's Disease.

    Science.gov (United States)

    Franke, Sigrid K; van Kesteren, Ronald E; Hofman, Sam; Wubben, Jacqueline A M; Smit, August B; Philippens, Ingrid H C H M

    2016-01-01

    Insight into susceptibility mechanisms underlying Parkinson's disease (PD) would aid the understanding of disease etiology, enable target finding and benefit the development of more refined disease-modifying strategies. We used intermittent low-dose MPTP (0.5 mg/kg/week) injections in marmosets and measured multiple behavioral and neurochemical parameters. Genetically diverse monkeys from different breeding families were selected to investigate inter- and intrafamily differences in susceptibility to MPTP treatment. We show that such differences exist in clinical signs, in particular nonmotor PD-related behaviors, and that they are accompanied by differences in neurotransmitter levels. In line with the contribution of a genetic component, different susceptibility phenotypes could be traced back through genealogy to individuals of the different families. Our findings show that low-dose MPTP treatment in marmosets represents a clinically relevant PD model, with a window of opportunity to examine the onset of the disease, allowing the detection of individual variability in disease susceptibility, which may be of relevance for the diagnosis and treatment of PD in humans. © 2016 S. Karger AG, Basel.

  8. Personality prototypes in individuals with compulsive buying based on the Big Five Model.

    Science.gov (United States)

    Mueller, Astrid; Claes, Laurence; Mitchell, James E; Wonderlich, Steve A; Crosby, Ross D; de Zwaan, Martina

    2010-09-01

    Personality prototypes based on the Big Five factor model were investigated in a treatment-seeking sample of 68 individuals with compulsive buying (CB). Cluster analysis of the NEO Five-Factor Inventory (NEO-FFI) scales yielded two distinct personality clusters. Participants in cluster II scored significantly higher than those in cluster I on neuroticism and lower on the other four personality traits. Subjects in cluster II showed higher severity of CB, lower degree of control over CB symptoms, and were more anxious, interpersonally sensitive and impulsive. Furthermore, cluster II was characterized by higher rates of comorbid anxiety disorders, and cluster B personality disorders. The two personality prototypes did not differ with respect to obsessive-compulsive features. Finally and of considerable clinical significance, participants in cluster II reported lower remission rates after undergoing cognitive-behavioral therapy. Implications of the results for treatment are discussed. 2010 Elsevier Ltd. All rights reserved.

  9. Are Creative Individuals Bad Apples? A Dual Pathway Model of Unethical Behavior.

    Science.gov (United States)

    Keem, Sejin; Shalley, Christina E; Kim, Eugene; Jeong, Inseong

    2017-12-14

    Research has been inconsistent in its quest to discover whether dispositional creativity is associated with more or less unethical behavior. Drawing on social cognitive theory, we propose that moral disengagement and moral imagination are 2 parallel mechanisms that encourage or inhibit unethical behavior, and that which of these mediation processes occur depends on moral identity. Study 1, a 3-wave study of a food service organization, shows that employees high on both dispositional creativity and moral identity are less likely to be morally disengaged and behave less unethically. The results of Study 2 replicate Study 1's findings in a scenario-based study of college students, and further show that individuals who are high on both dispositional creativity and moral identity are more likely to be morally imaginative and to behave less unethically. Theoretical and practical implications of our model are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  10. Meningkatkan Prestasi Belajar IPS Materi Interaksi Sosial Melalui Penggunaan Model Pembelajaran Team Assisted Individualization (TAI

    Directory of Open Access Journals (Sweden)

    Juliastuti .

    2017-01-01

    Full Text Available Berdasarkan hasil observasi dan wawancara dengan guru mata pelajaran IPS di SMPN 33 Surabaya Kota Surabaya, diperoleh bahwa nilai rata-rata penguasaan materi siswa kelas X1 pada materi Interaksi Sosial tahun pelajaran 2012/2013 masih rendah. Aktivitas siswa yang relevan dengan pembelajaran rendah. Salah satu upaya untuk meningkatkan aktivitas siswa dan penguasaan materi Interaksi Sosial adalah dengan menerapkan model pembelajaran kooperatif tipe TAI (Team Asissted Individualization. Tujuan penelitian ini adalah mendeskripsikan penggunaan pembelajaran kooperatif tipe TAI untuk meningkatkan persentase rata-rata : (1 tiap jenis aktivitas siswa; (2 penguasaan materi siswa dari siklus ke siklus. Penelitian ini adalah penelitian tindakan kelas yang dilakukan sebanyak tiga siklus. Data penelitian ini terdiri dari data kualitatif, yaitu data aktivitas on task siswa yang diperoleh dari lembar observasi, serta data kuantitatif berupa nilai penguasaan materi interaksi sosial yang diperoleh melalui tes formatif. Hasil penelitian ini menunjukkan bahwa penggunaan model pembelajaran kooperatif tipe memiliki dampak positif dalam meningkatkan prestasi belajar siswa yang ditandai dengan peningkatan ketuntasan belajar siswa dalam setiap siklus, yaitu siklus I 65,63%, siklus II 100%. Kata Kunci : Team Assisted Individualization ( TAI , Prestasi Belajar, IPS                                                                                                                        Based on observations and interviews with a social studies teacher at SMPN 33 Surabaya Surabaya, found that the average value of students' mastery of the material in the material class X1 Social Interaction in the academic year 2012/2013 is still low. Activities relevant to the learning of students is low. One effort to increase student activity and mastery of Social Interaction

  11. Calculation of Individual Tree Water Use in a Bornean Tropical Rain Forest Using Individual-Based Dynamic Vegetation Model SEIB-DGVM

    Science.gov (United States)

    Nakai, T.; Kumagai, T.; Saito, T.; Matsumoto, K.; Kume, T.; Nakagawa, M.; Sato, H.

    2015-12-01

    Bornean tropical rain forests are among the moistest biomes of the world with abundant rainfall throughout the year, and considered to be vulnerable to a change in the rainfall regime; e.g., high tree mortality was reported in such forests induced by a severe drought associated with the ENSO event in 1997-1998. In order to assess the effect (risk) of future climate change on eco-hydrology in such tropical rain forests, it is important to understand the water use of trees individually, because the vulnerability or mortality of trees against climate change can depend on the size of trees. Therefore, we refined the Spatially Explicit Individual-Based Dynamic Global Vegetation Model (SEIB-DGVM) so that the transpiration and its control by stomata are calculated for each individual tree. By using this model, we simulated the transpiration of each tree and its DBH-size dependency, and successfully reproduced the measured data of sap flow of trees and eddy covariance flux data obtained in a Bornean lowland tropical rain forest in Lambir Hills National Park, Sarawak, Malaysia.

  12. Exact Solution of the Gyration Radius of an Individual's Trajectory for a Simplified Human Regular Mobility Model

    Science.gov (United States)

    Yan, Xiao-Yong; Han, Xiao-Pu; Zhou, Tao; Wang, Bing-Hong

    2011-12-01

    We propose a simplified human regular mobility model to simulate an individual's daily travel with three sequential activities: commuting to workplace, going to do leisure activities and returning home. With the assumption that the individual has a constant travel speed and inferior limit of time at home and in work, we prove that the daily moving area of an individual is an ellipse, and finally obtain an exact solution of the gyration radius. The analytical solution captures the empirical observation well.

  13. Finite element modeling of penetration of rigid cylindrical bar impacting on a clamped circular plate, employing a strain rate dependent flow rate and a Gruneisen equation of state

    International Nuclear Information System (INIS)

    Tariq, M.; Khan, I.A.

    2003-01-01

    A time dependent Finite Element simulation of penetration of a rigid cylindrical bar impacting on a copper plate is conducted, to demonstrate how material behavior appears to change when Johnson-Cook plasticity rule is employed along with a Gruneisen, equation of state with cubic shock velocity-particle relationship, and defining pressure both for compressed and expanded materials, as compared to the behavior when only isotropic strain-hardening model is employed. The bar impacts the plate with a velocity of 1000 m/s, and penetrates the plate, a portion of it coming out of the other side. Results are obtained and compared taking both an isotropic strain-hardening model, and a model incorporating Johnson-Cook flow rule along with Gruneisen equation of state. (author)

  14. Sandeel ( Ammodytes marinus ) larval transport patterns in the North Sea from an individual-based hydrodynamic egg and larval model

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Jensen, Henrik; Mosegaard, Henrik

    2008-01-01

    is modelled by a stochastic, nonlinear degree-day model describing the extended hatch period. The larval growth model is parameterized by individually back-tracking the local physical environment of larval survivors from their catch location and catch time. Using a detailed map of sandeel habitats...

  15. The Combined Use of Video Modeling and Social Stories in Teaching Social Skills for Individuals with Intellectual Disability

    Science.gov (United States)

    Gül, Seray Olçay

    2016-01-01

    There are many studies in the literature in which individuals with intellectual disabilities exhibit social skills deficits and which show the need for teaching these skills systematically. This study aims to investigate the effects of an intervention package of consisting computer-presented video modeling and Social Stories on individuals with…

  16. The partnership model: working with individuals, families, and communities toward a new vision of health.

    Science.gov (United States)

    Courtney, R; Ballard, E; Fauver, S; Gariota, M; Holland, L

    1996-06-01

    Increasingly, health professionals must learn to work in new partnership relationships with clients and community to promote health effectively. A partnership requires a transformation of the professional role from chief actor to partner, and the client role from passive recipient to partner. A partnership approach has particular merit in a reformed health care system that increasingly emphasizes active involvement and self-care actions of individuals and families to maintain health and prevent disease. A partnership approach is also important to professionals working with underserved, vulnerable, and/or minority populations. For too long professionals and policymakers have relegated these groups to passive roles in health decision making and action. This article will provide a description of the partnership process as it has been developed and implemented by nurse practitioners in an urban Hispanic community with emphasis on a community partnership. A partnership model is described and compared to the more traditional professional model. A definition and essential criteria for partnership are presented. Finally, a specific example of how the partnership process was implemented at the community level is discussed.

  17. Taxonomic analysis of perceived risk: modeling individual and group perceptions within homogeneous hazard domains

    International Nuclear Information System (INIS)

    Kraus, N.N.; Slovic, P.

    1988-01-01

    Previous studies of risk perception have typically focused on the mean judgments of a group of people regarding the riskiness (or safety) of a diverse set of hazardous activities, substances, and technologies. This paper reports the results of two studies that take a different path. Study 1 investigated whether models within a single technological domain were similar to previous models based on group means and diverse hazards. Study 2 created a group taxonomy of perceived risk for only one technological domain, railroads, and examined whether the structure of that taxonomy corresponded with taxonomies derived from prior studies of diverse hazards. Results from Study 1 indicated that the importance of various risk characteristics in determining perceived risk differed across individuals and across hazards, but not so much as to invalidate the results of earlier studies based on group means and diverse hazards. In Study 2, the detailed analysis of railroad hazards produced a structure that had both important similarities to, and dissimilarities from, the structure obtained in prior research with diverse hazard domains. The data also indicated that railroad hazards are really quite diverse, with some approaching nuclear reactors in their perceived seriousness. These results suggest that information about the diversity of perceptions within a single domain of hazards could provide valuable input to risk-management decisions

  18. Application of an Individual-Based Transmission Hazard Model for Estimation of Influenza Vaccine Effectiveness in a Household Cohort.

    Science.gov (United States)

    Petrie, Joshua G; Eisenberg, Marisa C; Ng, Sophia; Malosh, Ryan E; Lee, Kyu Han; Ohmit, Suzanne E; Monto, Arnold S

    2017-12-15

    Household cohort studies are an important design for the study of respiratory virus transmission. Inferences from these studies can be improved through the use of mechanistic models to account for household structure and risk as an alternative to traditional regression models. We adapted a previously described individual-based transmission hazard (TH) model and assessed its utility for analyzing data from a household cohort maintained in part for study of influenza vaccine effectiveness (VE). Households with ≥4 individuals, including ≥2 children hazards (PH) models. For each individual, TH models estimated hazards of infection from the community and each infected household contact. Influenza A(H3N2) infection was laboratory-confirmed in 58 (4%) subjects. VE estimates from both models were similarly low overall (Cox PH: 20%, 95% confidence interval: -57, 59; TH: 27%, 95% credible interval: -23, 58) and highest for children Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Limitations of individual causal models, causal graphs, and ignorability assumptions, as illustrated by random confounding and design unfaithfulness.

    Science.gov (United States)

    Greenland, Sander; Mansournia, Mohammad Ali

    2015-10-01

    We describe how ordinary interpretations of causal models and causal graphs fail to capture important distinctions among ignorable allocation mechanisms for subject selection or allocation. We illustrate these limitations in the case of random confounding and designs that prevent such confounding. In many experimental designs individual treatment allocations are dependent, and explicit population models are needed to show this dependency. In particular, certain designs impose unfaithful covariate-treatment distributions to prevent random confounding, yet ordinary causal graphs cannot discriminate between these unconfounded designs and confounded studies. Causal models for populations are better suited for displaying these phenomena than are individual-level models, because they allow representation of allocation dependencies as well as outcome dependencies across individuals. Nonetheless, even with this extension, ordinary graphical models still fail to capture distinctions between hypothetical superpopulations (sampling distributions) and observed populations (actual distributions), although potential-outcome models can be adapted to show these distinctions and their consequences.

  20. Linking hearing impairment, employment and education.

    Science.gov (United States)

    Garramiola-Bilbao, I; Rodríguez-Álvarez, A

    2016-12-01

    To analyse the impact that hearing impairment and other relevant variables have on the education and employment situation of those affected by it in the Principality of Asturias, Spain. To achieve this objective, two discrete choice models (probit) are presented. The first one associates, among other variables, hearing impairment with the individual's employment status and in the second model, an ordered multinomial probit model is used to analyse, among other variables, how the impairment affects the individual's level of studies. Although the levels of statistical significance are low, the model's estimates appear to indicate that hearing impairment in Spain increases the probability of being unemployed by 18.4% (P = 0.09). Additionally, the people suffering from such a disability are, compared with the rest of the population, 10.2% (P = 0.05) more likely to have only completed elementary studies without pursuing any further education. If an individual is able to reach a level of secondary or higher education thus enabling a future incorporation to the work place, a benefit is obviously generated for both the individual as well as society (which has additionally incurred an investment in human capital). In this regard, encouraging the education of hearing-impaired students would profit both the individual (who receives an early integration as a child), which may contribute positively to family and social factors, as well as society who have incurred the investment. Therefore, our result could indicate that programmes created to support individuals with this type of disability represent an increase of welfare both individually and socially. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  1. 75 FR 3168 - Vocational Rehabilitation and Employment Program-Self-Employment

    Science.gov (United States)

    2010-01-20

    ..., prior to authorizing a rehabilitation plan leading to self-employment (a ``self-employment plan''). The... Employment Program--Self-Employment AGENCY: Department of Veterans Affairs. ACTION: Final rule. SUMMARY: This... Affairs (VA) concerning self-employment for individuals with qualifying disabilities. We are making...

  2. Individual differences in boys' and girls' timing and tempo of puberty: modeling development with nonlinear growth models.

    Science.gov (United States)

    Marceau, Kristine; Ram, Nilam; Houts, Renate M; Grimm, Kevin J; Susman, Elizabeth J

    2011-09-01

    Pubertal development is a nonlinear process progressing from prepubescent beginnings through biological, physical, and psychological changes to full sexual maturity. To tether theoretical concepts of puberty with sophisticated longitudinal, analytical models capable of articulating pubertal development more accurately, we used nonlinear mixed-effects models to describe both the timing and tempo of pubertal development in the sample of 364 White boys and 373 White girls measured across 6 years as part of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development. Individual differences in timing and tempo were extracted with models of logistic growth. Differential relations emerged for how boys' and girls' timing and tempo of development were related to physical characteristics (body mass index, height, and weight) and psychological outcomes (internalizing problems, externalizing problems, and risky sexual behavior). Timing and tempo are associated in boys but not girls. Pubertal timing and tempo are particularly important for predicting psychological outcomes in girls but only sparsely related to boys' psychological outcomes. Results highlight the importance of considering the nonlinear nature of puberty and expand the repertoire of possibilities for examining important aspects of how and when pubertal processes contribute to development.

  3. Individual-Based Modeling Approach to Assessment of the Impacts of Landscape Complexity and Climate on Dispersion, Detectability and Fate of Incipient Medfly Populations

    Directory of Open Access Journals (Sweden)

    Slawomir A. Lux

    2018-01-01

    Full Text Available The objective of the presented study was to demonstrate the potential of a bottom-up “ethological” approach and individual-based model of Markov-like stochastic processes, employed to gain insights into the factors driving behavior and fate of the invasive propagule, which determine the initial stages of pest invasion and “cryptic” existence of the localized, ultra-low density incipient pest populations. The applied model, PESTonFARM, is driven by the parameters derived directly from the behavior and biology of the target insect species, and spatiotemporal traits of the local terrain and climate. The model projections are actively generated by behavior of the primary causative actors of the invasion processes—individual “virtual” insects—members of the initial propagules or incipient populations. Algorithms of the model were adjusted to reflect behavior and ecology of the Mediterranean fruit fly, Ceratitis capitata, used as a case-example in the presented study. The model was parametrized based on compiled published experimental information about C. capitata behavior and development, and validated using published data from dispersion and trapping studies. The model reliably simulated behavior, development and dispersion of individual members of an invasive cohort, and allowed to quantify pest establishment and detection chances in landscapes of varying spatiotemporal complexity, host availability and climates. The results support the common view that, under optimal conditions (farmland with continuous fruit availability and suitable climate, even a single propagule of medium size (100 females usually results in pest establishment and detection within the first year post-invasion. The results demonstrate, however, that under specific sub-optimal conditions determined by the local climate, weather fluctuations and landscape topography (e.g., sub-urban, the incipient cryptic populations may occasionally continue for several

  4. Heterozygosity in an isolated population of a large mammal founded by four individuals is predicted by an individual-based genetic model.

    Directory of Open Access Journals (Sweden)

    Jaana Kekkonen

    Full Text Available Within-population genetic diversity is expected to be dramatically reduced if a population is founded by a low number of individuals. Three females and one male white-tailed deer Odocoileus virginianus, a North American species, were successfully introduced in Finland in 1934 and the population has since been growing rapidly, but remained in complete isolation from other populations.Based on 14 microsatellite loci, the expected heterozygosity H was 0.692 with a mean allelic richness (AR of 5.36, which was significantly lower than what was found in Oklahoma, U.S.A. (H = 0.742; AR = 9.07, demonstrating that a bottleneck occurred. Observed H was in line with predictions from an individual-based model where the genealogy of the males and females in the population were tracked and the population's demography was included.Our findings provide a rare within-population empirical test of the founder effect and suggest that founding a population by a small number of individuals need not have a dramatic impact on heterozygosity in an iteroparous species.

  5. Individual-level space-time analyses of emergency department data using generalized additive modeling

    Directory of Open Access Journals (Sweden)

    Vieira Verónica M

    2012-08-01

    Full Text Available Abstract Background Although daily emergency department (ED data is a source of information that often includes residence, its potential for space-time analyses at the individual level has not been fully explored. We propose that ED data collected for surveillance purposes can also be used to inform spatial and temporal patterns of disease using generalized additive models (GAMs. This paper describes the methods for adapting GAMs so they can be applied to ED data. Methods GAMs are an effective approach for modeling spatial and temporal distributions of point-wise data, producing smoothed surfaces of continuous risk while adjusting for confounders. In addition to disease mapping, the method allows for global and pointwise hypothesis testing and selection of statistically optimum degree of smoothing using standard statistical software. We applied a two-dimensional GAM for location to ED data of overlapping calendar time using a locally-weighted regression smoother. To illustrate our methods, we investigated the association between participants’ address and the risk of gastrointestinal illness in Cape Cod, Massachusetts over time. Results The GAM space-time analyses simultaneously smooth in units of distance and time by using the optimum degree of smoothing to create data frames of overlapping time periods and then spatially analyzing each data frame. When resulting maps are viewed in series, each data frame contributes a movie frame, allowing us to visualize changes in magnitude, geographic size, and location of elevated risk smoothed over space and time. In our example data, we observed an underlying geographic pattern of gastrointestinal illness with risks consistently higher in the eastern part of our study area over time and intermittent variations of increased risk during brief periods. Conclusions Spatial-temporal analysis of emergency department data with GAMs can be used to map underlying disease risk at the individual-level and view

  6. Characterization of Atomoxetine Biotransformation and Implications for Development of PBPK Models for Dose Individualization in Children

    Science.gov (United States)

    Pearce, Robin E.; Van Haandel, Leon; Gaedigk, Andrea; Leeder, J. Steven

    2016-01-01

    Atomoxetine (ATX) is a second-line nonstimulant medication used to control symptoms of attention deficit hyperactivity disorder (ADHD). Inconsistent therapeutic efficacy has been reported with ATX, which may be related to variable CYP2D6-mediated drug clearance. We characterized ATX metabolism in a panel of human liver samples as a basis for a bottom-up PBPK model to aid in ATX exposure prediction and control. Km, Vmax, and Clint values in pooled human liver microsomes (HLMs) were 2.4 µM, 479 pmol/min/mg protein, and 202 µl/min/mg protein, respectively. Mean population values of kinetic parameters are not adequate to describe variability in a population, given that Km, Vmax, and Clint values from single-donor HLMs ranged from 0.93 to 79.2 µM, 20.0 to 1600 pmol/min/mg protein, and 0.3 to 936 µl/min/mg protein. All kinetic parameters were calculated from 4-hydroxyatomoxetine (4-OH-ATX) formation. CYP2E1 and CYP3A contributed to 4-OH-ATX formation in livers with CYP2D6 intermediate and poor metabolizer status. In HLMs with lower CYP2D6 activity levels, 2-hydroxymethylatomoxetine (2-CH2OH-ATX) formation became a more predominant pathway of metabolism, which appeared to be catalyzed by CYP2B6. ATX biotransformation at clinically relevant plasma concentrations was characterized in a panel of pediatric HLM (n = 116) samples by evaluating primary metabolites. Competing pathways of ATX metabolism [N-desmethylatomoxetine (NDM-ATX) and 2-CH2OH-ATX formation] had increasing importance in livers with lesser CYP2D6 activity, but, overall ATX clearance was still compromised. Modeling ATX exposure to individualize therapy would require comprehensive knowledge of factors that affect CYP2D6 activity as well as an understanding of competing pathways, particularly for individuals with lower CYP2D6 activity. PMID:27052878

  7. Assessing Individual Weather Risk-Taking and Its Role in Modeling Likelihood of Hurricane Evacuation

    Science.gov (United States)

    Stewart, A. E.

    2017-12-01

    This research focuses upon measuring an individual's level of perceived risk of different severe and extreme weather conditions using a new self-report measure, the Weather Risk-Taking Scale (WRTS). For 32 severe and extreme situations in which people could perform an unsafe behavior (e. g., remaining outside with lightning striking close by, driving over roadways covered with water, not evacuating ahead of an approaching hurricane, etc.), people rated: 1.their likelihood of performing the behavior, 2. The perceived risk of performing the behavior, 3. the expected benefits of performing the behavior, and 4. whether the behavior has actually been performed in the past. Initial development research with the measure using 246 undergraduate students examined its psychometric properties and found that it was internally consistent (Cronbach's a ranged from .87 to .93 for the four scales) and that the scales possessed good temporal (test-retest) reliability (r's ranged from .84 to .91). A second regression study involving 86 undergraduate students found that taking weather risks was associated with having taken similar risks in one's past and with the personality trait of sensation-seeking. Being more attentive to the weather and perceiving its risks when it became extreme was associated with lower likelihoods of taking weather risks (overall regression model, R2adj = 0.60). A third study involving 334 people examined the contributions of weather risk perceptions and risk-taking in modeling the self-reported likelihood of complying with a recommended evacuation ahead of a hurricane. Here, higher perceptions of hurricane risks and lower perceived benefits of risk-taking along with fear of severe weather and hurricane personal self-efficacy ratings were all statistically significant contributors to the likelihood of evacuating ahead of a hurricane. Psychological rootedness and attachment to one's home also tend to predict lack of evacuation. This research highlights the

  8. Entrepreneurship and Employment Stability

    DEFF Research Database (Denmark)

    Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

    2017-01-01

    are identified and empirically explored: (i) job matching, (ii) labour market value, and (iii) personal commitment. Entrepreneurs appear to be more productive and thus better matched compared to wageworkers. However, they also appear to be locked in entrepreneurship because of their anticipated lower value......This paper challenges the conventional belief that entrepreneurship is an unstable career path. Using longitudinal matched employer–employee data from Denmark, the analysis reveals that a transition to entrepreneurship decreases individual's employment turnover tendency. Three explanations...... in the labour market and because of their personal attachment to the venture. The counter-intuitive finding – entrepreneurship yields greater employment stability – only holds with respect to subsequent transitions to wagework and not for new venture founding. The results have implications for our understanding...

  9. Employers' Guide to the Employment Equity Act

    Directory of Open Access Journals (Sweden)

    Lesley-Anne Katz

    2001-12-01

    Full Text Available Employers' Guide to the Employment Equity Act is aimed, according to the author, at assisting those in the labour arena (employers, managers, labour relations practitioners, union officials, and students to develop a practical understanding of the Employment Equity Act (hereafter, the Act.

  10. Analysis of the main thermoluminescent peak of the glow curve of K2YF5:Pr3+ crystals employing a model of interactive traps

    International Nuclear Information System (INIS)

    Marcazzo, J.; Molina, P.; Ortega, F.; Santiago, M.; Spano, F.; Khaidukov, N.; Caselli, E.

    2008-01-01

    By employing a model of interactive traps which conforms to experimental findings the glow curve of K 2 YF 5 :Pr 3+ compounds has been analysed. A novel algorithm, which allows the decoupling of the equations describing the carrier traffic among traps, recombination centres and energy bands, is reported. An important conclusion drawn from the results is that it is not always correct to think of each single peak as related only to one trap

  11. 12 CFR 268.705 - Employment.

    Science.gov (United States)

    2010-01-01

    ... Physical or Mental Disability § 268.705 Employment. No qualified individual with a disability shall, on the basis of a disability, be subjected to discrimination in employment under any program or activity...

  12. Employing Disabled Persons in Leisure Service Agencies.

    Science.gov (United States)

    Shank, John W.

    1984-01-01

    This article discusses a study that explored barriers to the employment of physically disabled persons in leisure services and the extent to which selected actions would increase the potential employment of these individuals. (JMK)

  13. A cognitive model for multidigit number reading: Inferences from individuals with selective impairments.

    Science.gov (United States)

    Dotan, Dror; Friedmann, Naama

    2018-04-01

    We propose a detailed cognitive model of multi-digit number reading. The model postulates separate processes for visual analysis of the digit string and for oral production of the verbal number. Within visual analysis, separate sub-processes encode the digit identities and the digit order, and additional sub-processes encode the number's decimal structure: its length, the positions of 0, and the way it is parsed into triplets (e.g., 314987 → 314,987). Verbal production consists of a process that generates the verbal structure of the number, and another process that retrieves the phonological forms of each number word. The verbal number structure is first encoded in a tree-like structure, similarly to syntactic trees of sentences, and then linearized to a sequence of number-word specifiers. This model is based on an investigation of the number processing abilities of seven individuals with different selective deficits in number reading. We report participants with impairment in specific sub-processes of the visual analysis of digit strings - in encoding the digit order, in encoding the number length, or in parsing the digit string to triplets. Other participants were impaired in verbal production, making errors in the number structure (shifts of digits to another decimal position, e.g., 3,040 → 30,004). Their selective deficits yielded several dissociations: first, we found a double dissociation between visual analysis deficits and verbal production deficits. Second, several dissociations were found within visual analysis: a double dissociation between errors in digit order and errors in the number length; a dissociation between order/length errors and errors in parsing the digit string into triplets; and a dissociation between the processing of different digits - impaired order encoding of the digits 2-9, without errors in the 0 position. Third, within verbal production, a dissociation was found between digit shifts and substitutions of number words. A

  14. A structural model of treatment program and individual counselor leadership in innovation transfer.

    Science.gov (United States)

    Joe, George W; Becan, Jennifer E; Knight, Danica K; Flynn, Patrick M

    2017-03-23

    A number of program-level and counselor-level factors are known to impact the adoption of treatment innovations. While program leadership is considered a primary factor, the importance of leadership among clinical staff to innovation transfer is less known. Objectives included explore (1) the influence of two leadership roles, program director and individual counselor, on recent training activity and (2) the relationship of counselor attributes on training endorsement. The sample included 301 clinical staff in 49 treatment programs. A structural equation model was evaluated for key hypothesized relationships between exogenous and endogenous variables related to the two leadership roles. The importance of organizational leadership, climate, and counselor attributes (particularly counseling innovation interest and influence) to recent training activity was supported. In a subset of 68 counselors who attended a developer-led training on a new intervention, it was found that training endorsement was higher among those with high innovation interest and influence. The findings suggest that each leadership level impacts the organization in different ways, yet both can promote or impede technology transfer.

  15. A Model-Based Systems Engineering Methodology for Employing Architecture In System Analysis: Developing Simulation Models Using Systems Modeling Language Products to Link Architecture and Analysis

    Science.gov (United States)

    2016-06-01

    Filling Designs for Complex System Simulations.” Ph.D. Dissertation, Naval Postgraduate School. MacCalman, Alex, Hyangshim Kwak, Mary McDonald, and...Michael, Peter Bryant, Mike Wilkinson, Paul King, Ady James, and Stuart Arnold. 2012. “Interpreting ‘Systems Architecting.’” Systems Engineering 15(4...Hyangshim Kwak, Mary McDonald, and Stephen Upton. 2015. “Capturing experimental design insights in support of the model-based systems engineering approach

  16. Optimization of biomathematical model predictions for cognitive performance impairment in individuals: accounting for unknown traits and uncertain states in homeostatic and circadian processes.

    Science.gov (United States)

    Van Dongen, Hans P A; Mott, Christopher G; Huang, Jen-Kuang; Mollicone, Daniel J; McKenzie, Frederic D; Dinges, David F

    2007-09-01

    Current biomathematical models of fatigue and performance do not accurately predict cognitive performance for individuals with a priori unknown degrees of trait vulnerability to sleep loss, do not predict performance reliably when initial conditions are uncertain, and do not yield statistically valid estimates of prediction accuracy. These limitations diminish their usefulness for predicting the performance of individuals in operational environments. To overcome these 3 limitations, a novel modeling approach was developed, based on the expansion of a statistical technique called Bayesian forecasting. The expanded Bayesian forecasting procedure was implemented in the two-process model of sleep regulation, which has been used to predict performance on the basis of the combination of a sleep homeostatic process and a circadian process. Employing the two-process model with the Bayesian forecasting procedure to predict performance for individual subjects in the face of unknown traits and uncertain states entailed subject-specific optimization of 3 trait parameters (homeostatic build-up rate, circadian amplitude, and basal performance level) and 2 initial state parameters (initial homeostatic state and circadian phase angle). Prior information about the distribution of the trait parameters in the population at large was extracted from psychomotor vigilance test (PVT) performance measurements in 10 subjects who had participated in a laboratory experiment with 88 h of total sleep deprivation. The PVT performance data of 3 additional subjects in this experiment were set aside beforehand for use in prospective computer simulations. The simulations involved updating the subject-specific model parameters every time the next performance measurement became available, and then predicting performance 24 h ahead. Comparison of the predictions to the subjects' actual data revealed that as more data became available for the individuals at hand, the performance predictions became

  17. Predicting sickness absence-are extended health check-ups of any value? Comparisons of three individual risk models.

    Science.gov (United States)

    Falkenberg, Anna; Nyfjäll, Mats; Bildt, Carina; Vingård, Eva

    2009-01-01

    To predict sickness absence by three health check-up models. A study group of 821 participants from the public sector in Sweden where three health check-up models were compared 1) the limited variable model including smoking, body mass index, blood pressure, and cholesterol, 2) the several variable model including smoking, waist-hip ratio, blood pressure, relation between low density lipoproteins and high density lipoproteins, serum triglycerides, and fitness test, and 3) Self-rated health measured by one single question. Sickness absence data during 1 year was delivered from the employer. The three models served their purpose to predict sickness absence. The self-rated health-model with one single question has as good quality in predestination as more complicated models. This may have an implication for cost-effective procedures in occupational health services.

  18. Employment Effects of Renewable Energy Expansion on a Regional Level—First Results of a Model-Based Approach for Germany

    Directory of Open Access Journals (Sweden)

    Ulrike Lehr

    2012-02-01

    Full Text Available National studies have shown that both gross and net effects of the expansion of energy from renewable sources on employment are positive for Germany. These modeling approaches also revealed that this holds true for both present and future perspectives under certain assumptions on the development of exports, fossil fuel prices and national politics. Yet how are employment effects distributed within Germany? What components contribute to growth impacts on a regional level? To answer these questions (new methods of regionalization were explored and developed for the example “wind energy onshore” for Germany’s federal states. The main goal was to develop a methodology which is applicable to all renewable energy technologies in future research. For the quantification and projection, it was necessary to distinguish between jobs generated by domestic investments and exports on the one hand, and jobs for operation and maintenance of existing plants on the other hand. Further, direct and indirect employment is analyzed. The results show, that gross employment is particularly high in the northwestern regions of Germany. However, especially the indirect effects are spread out over the whole country. Regions in the south not only profit from the delivery of specific components, but also from other industry and service inputs.

  19. Employing Second-Order Circular Suprasegmental Hidden Markov Models to Enhance Speaker Identification Performance in Shouted Talking Environments

    Directory of Open Access Journals (Sweden)

    Ismail Shahin

    2010-01-01

    Full Text Available Speaker identification performance is almost perfect in neutral talking environments. However, the performance is deteriorated significantly in shouted talking environments. This work is devoted to proposing, implementing, and evaluating new models called Second-Order Circular Suprasegmental Hidden Markov Models (CSPHMM2s to alleviate the deteriorated performance in the shouted talking environments. These proposed models possess the characteristics of both Circular Suprasegmental Hidden Markov Models (CSPHMMs and Second-Order Suprasegmental Hidden Markov Models (SPHMM2s. The results of this work show that CSPHMM2s outperform each of First-Order Left-to-Right Suprasegmental Hidden Markov Models (LTRSPHMM1s, Second-Order Left-to-Right Suprasegmental Hidden Markov Models (LTRSPHMM2s, and First-Order Circular Suprasegmental Hidden Markov Models (CSPHMM1s in the shouted talking environments. In such talking environments and using our collected speech database, average speaker identification performance based on LTRSPHMM1s, LTRSPHMM2s, CSPHMM1s, and CSPHMM2s is 74.6%, 78.4%, 78.7%, and 83.4%, respectively. Speaker identification performance obtained based on CSPHMM2s is close to that obtained based on subjective assessment by human listeners.

  20. Exploring example models of cross-sector, sessional employment of pharmacists to improve medication management and pharmacy support in rural hospitals.

    Science.gov (United States)

    Tan, Amy Cw; Emmerton, Lynne M; Hattingh, Laetitia; La Caze, Adam

    2015-01-01

    Many rural hospitals in Australia are not large enough to sustain employment of a full-time pharmacist, or are unable to recruit or retain a full-time pharmacist. The absence of a pharmacist may result in hospital nurses undertaking medication-related roles outside their scope of practice. A potential solution to address rural hospitals' medication management needs is contracted part-time ('sessional') employment of a local pharmacist external to the hospital ('cross-sector'). The aim of this study was to explore the roles and experiences of pharmacists in their provision of sessional services to rural hospitals with no on-site pharmacist and explore how these roles could potentially address shortfalls in medication management in rural hospitals. A qualitative study was conducted to explore models with pharmacists who had provided sessional services to a rural hospital. A semi-structured interview guide was informed by a literature review, preliminary research and stakeholder consultation. Participants were recruited via advertisement and personal contacts. Consenting pharmacists were interviewed between August 2012 and January 2013 via telephone or Skype for 40-55 minutes. Thirteen pharmacists with previous or ongoing hospital sessional contracts in rural communities across Australia and New Zealand participated. Most commonly, the pharmacists provided weekly services to rural hospitals. All believed the sessional model was a practical solution to increase hospital access to pharmacist-mediated support and to address medication management gaps. Roles perceived to promote quality use of medicines were inpatient consultation services, medicines information/education to hospital staff, assistance with accreditation matters and system reviews, and input into pharmaceutical distribution activities. This study is the first to explore the concept of sessional rural hospital employment undertaken by pharmacists in Australia and New Zealand. Insights from participants

  1. Structure and mechanism of diet specialisation: testing models of individual variation in resource use with sea otters

    Science.gov (United States)

    Tinker, M. Tim; Guimarães, Paulo R.; Novak, Mark; Marquitti, Flavia Maria Darcie; Bodkin, James L.; Staedler, Michelle; Bentall, Gena B.; Estes, James A.

    2012-01-01

    Studies of consumer-resource interactions suggest that individual diet specialisation is empirically widespread and theoretically important to the organisation and dynamics of populations and communities. We used weighted networks to analyze the resource use by sea otters, testing three alternative models for how individual diet specialisation may arise. As expected, individual specialisation was absent when otter density was low, but increased at high-otter density. A high-density emergence of nested resource-use networks was consistent with the model assuming individuals share preference ranks. However, a density-dependent emergence of a non-nested modular network for ‘core’ resources was more consistent with the ‘competitive refuge’ model. Individuals from different diet modules showed predictable variation in rank-order prey preferences and handling times of core resources, further supporting the competitive refuge model. Our findings support a hierarchical organisation of diet specialisation and suggest individual use of core and marginal resources may be driven by different selective pressures.

  2. A spatially distributed hydroeconomic model to assess the effects of drought on land use, farm profits, and agricultural employment

    Science.gov (United States)

    Maneta, M. P.; Torres, M. O.; Wallender, W. W.; Vosti, S.; Howitt, R.; Rodrigues, L.; Bassoi, L. H.; Panday, S.

    2009-11-01

    In this paper a high-resolution linked hydroeconomic model is demonstrated for drought conditions in a Brazilian river basin. The economic model of agriculture includes 13 decision variables that can be optimized to maximize farmers' yearly net revenues. The economic model uses a multi-input multioutput nonlinear constant elasticity of substitution (CES) production function simulating agricultural production. The hydrologic component is a detailed physics-based three-dimensional hydrodynamic model that simulates changes in the hydrologic system derived from agricultural activity while in turn providing biophysical constraints to the economic system. The linked models capture the effects of the interactions between the hydrologic and the economic systems at high spatial and temporal resolutions, ensuring that the model converges to an optimal economic scenario that takes into account the spatial and temporal distribution of the water resources. The operation and usefulness of the models are demonstrated in a rural catchment area of about 10 km2 within the São Francisco River Basin in Brazil. Two droughts of increasing intensity are simulated to investigate how farmers behave under rain shortfalls of different severity. The results show that farmers react to rainfall shortages to minimize their effects on farm profits, and that the impact on farmers depends, among other things, on their location in the watershed and on their access to groundwater.

  3. Euler Technology Assessment - SPLITFLOW Code Applications for Stability and Control Analysis on an Advanced Fighter Model Employing Innovative Control Concepts

    Science.gov (United States)

    Jordan, Keith J.

    1998-01-01

    This report documents results from the NASA-Langley sponsored Euler Technology Assessment Study conducted by Lockheed-Martin Tactical Aircraft Systems (LMTAS). The purpose of the study was to evaluate the ability of the SPLITFLOW code using viscous and inviscid flow models to predict aerodynamic stability and control of an advanced fighter model. The inviscid flow model was found to perform well at incidence angles below approximately 15 deg, but not as well at higher angles of attack. The results using a turbulent, viscous flow model matched the trends of the wind tunnel data, but did not show significant improvement over the Euler solutions. Overall, the predictions were found to be useful for stability and control design purposes.

  4. Cognitive Psychology Meets Psychometric Theory: On the Relation between Process Models for Decision Making and Latent Variable Models for Individual Differences

    Science.gov (United States)

    van der Maas, Han L. J.; Molenaar, Dylan; Maris, Gunter; Kievit, Rogier A.; Borsboom, Denny

    2011-01-01

    This article analyzes latent variable models from a cognitive psychology perspective. We start by discussing work by Tuerlinckx and De Boeck (2005), who proved that a diffusion model for 2-choice response processes entails a 2-parameter logistic item response theory (IRT) model for individual differences in the response data. Following this line…

  5. Cognitive psychology meets psychometric theory: on the relation between process models for decision making and latent variable models for individual differences

    NARCIS (Netherlands)

    van der Maas, H.L.J.; Molenaar, D.; Maris, G.; Kievit, R.A.; Borsboom, D.

    2011-01-01

    This article analyzes latent variable models from a cognitive psychology perspective. We start by discussing work by Tuerlinckx and De Boeck (2005), who proved that a diffusion model for 2-choice response processes entails a 2-parameter logistic item response theory (IRT) model for individual

  6. Discovering the Power of Individual-Based Modelling in Teaching and Learning: The Study of a Predator-Prey System

    Science.gov (United States)

    Ginovart, Marta

    2014-08-01

    The general aim is to promote the use of individual-based models (biological agent-based models) in teaching and learning contexts in life sciences and to make their progressive incorporation into academic curricula easier, complementing other existing modelling strategies more frequently used in the classroom. Modelling activities for the study of a predator-prey system for a mathematics classroom in the first year of an undergraduate program in biosystems engineering have been designed and implemented. These activities were designed to put two modelling approaches side by side, an individual-based model and a set of ordinary differential equations. In order to organize and display this, a system with wolves and sheep in a confined domain was considered and studied. With the teaching material elaborated and a computer to perform the numerical resolutions involved and the corresponding individual-based simulations, the students answered questions and completed exercises to achieve the learning goals set. Students' responses regarding the modelling of biological systems and these two distinct methodologies applied to the study of a predator-prey system were collected via questionnaires, open-ended queries and face-to-face dialogues. Taking into account the positive responses of the students when they were doing these activities, it was clear that using a discrete individual-based model to deal with a predator-prey system jointly with a set of ordinary differential equations enriches the understanding of the modelling process, adds new insights and opens novel perspectives of what can be done with computational models versus other models. The complementary views given by the two modelling approaches were very well assessed by students.

  7. Individual differences in response to automation: the five factor model of personality.

    Science.gov (United States)

    Szalma, James L; Taylor, Grant S

    2011-06-01

    This study examined the relationship of operator personality (Five Factor Model) and characteristics of the task and of adaptive automation (reliability and adaptiveness-whether the automation was well-matched to changes in task demand) to operator performance, workload, stress, and coping. This represents the first investigation of how the Five Factors relate to human response to automation. One-hundred-sixty-one college students experienced either 75% or 95% reliable automation provided with task loads of either two or four displays to be monitored. The task required threat detection in a simulated uninhabited ground vehicle (UGV) task. Task demand exerted the strongest influence on outcome variables. Automation characteristics did not directly impact workload or stress, but effects did emerge in the context of trait-task interactions that varied as a function of the dimension of workload and stress. The pattern of relationships of traits to dependent variables was generally moderated by at least one task factor. Neuroticism was related to poorer performance in some conditions, and all five traits were associated with at least one measure of workload and stress. Neuroticism generally predicted increased workload and stress and the other traits predicted decreased levels of these states. However, in the case of the relation of Extraversion and Agreeableness to Worry, Frustration, and avoidant coping, the direction of effects varied across task conditions. The results support incorporation of individual differences into automation design by identifying the relevant person characteristics and using the information to determine what functions to automate and the form and level of automation.

  8. Determining the Best Strategies for Maternally Targeted Pertussis Vaccination Using an Individual-Based Model.

    Science.gov (United States)

    Campbell, Patricia Therese; McVernon, Jodie; Geard, Nicholas

    2017-07-01

    Rising pertussis incidence has prompted a number of countries to implement maternally targeted vaccination strategies to protect vulnerable infants, but questions remain about the optimal design of such strategies. We simulated pertussis transmission within an individual-based model parameterized to match Australian conditions, explicitly linking infants and their mothers to estimate the effectiveness of alternative maternally targeted vaccination strategies (antenatal delivery vs. postnatal delivery) and the benefit of revaccination over the course of multiple pregnancies. For firstborn infants aged less than 2 months, antenatal immunization reduced annual pertussis incidence by 60%, from 780 per 100,000 firstborn children under age 2 months (interquartile range (IQR), 682-862) to 315 per 100,000 (IQR, 260-370), while postnatal vaccination produced a minimal reduction, with an incidence of 728 per 100,000 (IQR, 628-789). Subsequent infants obtained limited protection from a single antenatal dose, but revaccinating mothers during every pregnancy decreased incidence for these infants by 58%, from 1,878 per 100,000 subsequent children under age 2 months (IQR, 1,712-2,076) to 791 per 100,000 (IQR, 683-915). Subsequent infants also benefited from household-level herd immunity when antenatal vaccination for every pregnancy was combined with a toddler booster dose at age 18 months; incidence was reduced to 626 per 100,000 (IQR, 548-691). Our approach provides useful information to aid consideration of alternative maternally targeted vaccination strategies and can inform development of outcome measures for program evaluation. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. A contextual model of self-regulation change mechanisms among individuals with addictive disorders.

    Science.gov (United States)

    Roos, Corey R; Witkiewitz, Katie

    2017-11-01

    Numerous behavioral treatments for addictive disorders include components explicitly aimed at targeting self-regulation (e.g., coping and emotion regulation). We first provide a summary of key findings to date among studies that have examined self-regulation as a mechanism of behavior change (MOBC) in behavioral treatments for addictive disorders. Based on our review, we conclude that the role of self-regulation as a MOBC across behavioral treatments for addictive disorders is not well-characterized and findings are inconsistent across studies. For example, our review indicates that there is still inconsistent evidence that coping is a unique MOBC in cognitive-behavioral approaches for addictive behaviors. We propose that there has been slow progress in understanding self-regulation as a MOBC in addiction treatment because of a lack of attention to contextual factors. Accordingly, in the second half of this paper, we propose a contextual model of self-regulation change mechanisms, which emphasizes that the role of various facets of self-regulation as MOBC may depend on contextual factors in the immediate situational context (e.g., fluctuating internal and external cues) and in the broader context in which an individual is embedded (e.g., major life stressors, environmental conditions, dispositions). Additionally, we provide specific recommendations to guide future research for understanding both between-person and within-person self-regulation MOBC in addiction treatment. In particular, we provide key recommendations for how to capitalize on intensive longitudinal measurement methods (e.g., ecological momentary assessment) when bringing a contextual perspective to the study of self-regulation as MOBC in various addiction treatments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Population modeling using harpacticoid copepods : Bridging the gap between individual-level effects and protection goals of environmental risk assessment

    OpenAIRE

    Lundström Belleza, Elin

    2014-01-01

    To protect the environment from contaminants, environmental risk assessment (ERA) evaluates the risk of adverse effects to populations, communities and ecosystems. Environmental management decisions rely on ERAs, which commonly are based on a few endpoints at the individual organism level. To bridge the gap between what is measured and what is intended for protection, individual-level effects can be integrated in population models, and translated to the population level. The general aim of th...

  11. Patterns and individual-based modeling of spatial competition within two main components of Neotropical mangrove ecosystems.

    OpenAIRE

    Piou, Cyril

    2007-01-01

    The main focus of the thesis was to look at the role of competition in shaping the spatial organization of two main components of Neotropical mangrove ecosystems. The first component was the Caribbean mangrove tree community. The second was populations of an ecologically and economically important mangrove burrowing crab in North-Brazil: Ucides cordatus. These two components were studied in two respective parts with one field and two individual-based modeling studies each. The two individual-...

  12. Building Employer Capacity to Support Meaningful Employment for Persons with Developmental Disabilities: A Grounded Theory Study of Employment Support Perspectives.

    Science.gov (United States)

    Rashid, Marghalara; Hodgetts, Sandra; Nicholas, David

    2017-11-01

    To explore strategies to build employer capacity to support people with DD in meaningful employment from perspective of employment support workers. A grounded theory study was conducted with 34 employment support individuals. A theoretical sampling approach was used to identify and recruit participants from multiple sites in Ontario and Alberta. Three main themes, with seven sub-themes, emerged: (1) experiences of supporting employment finding for people with DD, (2) institutional influences on employee experiences, and (3) attitudes, assumptions and stigma. Several recommendations related to building employer capacity were offered. Our findings provide insight on specific elements and strategies that can support building employer capacity for persons with DD.

  13. Employment specialist competencies for supported employment programs

    NARCIS (Netherlands)

    Corbière, M.; Brouwers, E.P.M.; Lanctôt, N.; van Weeghel, J.

    2014-01-01

    Purpose Supported employment (SE) programs are evidence-based programs offered to people with severe mental illness to facilitate obtaining and keeping competitive work. However, significant variations in individuals’ vocational success may be partly explained by differences in their employment

  14. Employer-sponsored pension plans

    Directory of Open Access Journals (Sweden)

    Rakonjac-Antić Tatjana N.

    2004-01-01

    Full Text Available Apart from pension plans within social insurance, in developed pension systems there are also available to individuals schemes which may to a large extent ensure a significant part of their total pension. Among them are the following: employer-sponsored pension plans or individual pension plans. The most widely used employer-sponsored pension plan in the USA is 401(k, in which both the employer and the employee contribute to the financing of the pension. These contributions as well as the return to their investment have a preferential tax treatment, i.e. do not enter a tax base. The funds are taxed only when drawn from the account in the form of a pension. This paper aims to present the functioning of 401(k pension plan as the most widely used employer sponsored pension plan in the USA, which is likely, in a modified form, to have an important place within our future reformed pension insurance system.

  15. MODELING OF THE PROCESS OF FORMATION OF INDIVIDUAL MARKETING DEMAND: A COMPARATIVE ANALYSIS AND GENERALIZATION OF THE PRECEDING CORRESPONDING RESULTS

    Directory of Open Access Journals (Sweden)

    Anatoly V. Korotkov

    2015-01-01

    Full Text Available The article focuses on the modeling of series-STI formation of individual market demand. The analysis, and then sum-of three well-known inmarketing models, which exhaust the currentlyknown approaches is revised. The article shows that all three models have a signifi cant difference in the number of stages and terminology. The obtained results are the basis for the developmentof the author’s model of gradual development of demand - «need - desire - requirement -demand» or abbreviated as «model NDRD» and can be considered as a contribution to the methodology of study a demand.

  16. An individual program planning model of physical rehabilitation/therapy of a child with a bronchopulmonary disease

    Directory of Open Access Journals (Sweden)

    Nataliya Ivasyk

    2017-04-01

    Full Text Available Purpose: create a model of planning an individual program of physical rehabilitation/therapy of children with bronchopulmonary diseases. Material & Methods: general scientific – analysis, interpretation and synthesis, synthesis, comparing, abstracting. Results: a model of planning an individual program of physical rehabilitation/therapy of children with bronchopulmonary disease, which consists of five interrelated functional subsystems. Conclusion: the proposed model takes into consideration the clinical and functional examination of the data, based on which are determined by the problem, the aim is and the problem of physical rehabilitation, according to which the selected means, forms and methods of influence, the methods of their implementation and dosing criteria in accordance with the individual data of a child with bronchopulmonary disease. This is accomplished by changes in the order, content and structure interference in accordance with changes in the patient's condition.

  17. Multi-level modelling of the factors that influence the participation of disabled rural individuals in social medical insurance in China

    Science.gov (United States)

    2013-01-01

    Background The Second China National Sample Survey on Disability in 2006 showed that the participation rate of disabled Chinese rural individuals in social medical insurance participation was less than 30%. However, there has been limited number of studies on the influencing factors, especially contextual factors, affecting their participation in social medical insurance. Therefore, this study aimed to analyze the factors influencing the participation of disabled rural individuals in social medical insurance, including contextual factors. Methods Based on data derived from the Second China National Sample Survey on Disability, chi-square test and two-level logistic regression model were used to analyze the influencing factors. Results The results showed that the disabled rural individuals in the New Rural Cooperative Medical System pilot counties who lived in communities with rehabilitation stations or with higher per capita income of villagers were more likely to participate in the social medical insurance. Meanwhile, those employed, with less severe disability degree or with less severe barriers in participation in society were more likely to participate in the social medical insurance. Conclusions Contextual factors including economic and policy contexts were important factors influencing their participation in social medical insurance before 2006 in China. Unemployment, severer disability degree and social isolation might also prevent them from gaining equal access to social medical insurance. PMID:23402275

  18. Predictive modeling in Clostridium acetobutylicum fermentations employing Raman spectroscopy and multivariate data analysis for real-time culture monitoring

    Science.gov (United States)

    Zu, Theresah N. K.; Liu, Sanchao; Germane, Katherine L.; Servinsky, Matthew D.; Gerlach, Elliot S.; Mackie, David M.; Sund, Christian J.

    2016-05-01

    The coupling of optical fibers with Raman instrumentation has proven to be effective for real-time monitoring of chemical reactions and fermentations when combined with multivariate statistical data analysis. Raman spectroscopy is relatively fast, with little interference from the water peak present in fermentation media. Medical research has explored this technique for analysis of mammalian cultures for potential diagnosis of some cancers. Other organisms studied via this route include Escherichia coli, Saccharomyces cerevisiae, and some Bacillus sp., though very little work has been performed on Clostridium acetobutylicum cultures. C. acetobutylicum is a gram-positive anaerobic bacterium, which is highly sought after due to its ability to use a broad spectrum of substrates and produce useful byproducts through the well-known Acetone-Butanol-Ethanol (ABE) fermentation. In this work, real-time Raman data was acquired from C. acetobutylicum cultures grown on glucose. Samples were collected concurrently for comparative off-line product analysis. Partial-least squares (PLS) models were built both for agitated cultures and for static cultures from both datasets. Media components and metabolites monitored include glucose, butyric acid, acetic acid, and butanol. Models were cross-validated with independent datasets. Experiments with agitation were more favorable for modeling with goodness of fit (QY) values of 0.99 and goodness of prediction (Q2Y) values of 0.98. Static experiments did not model as well as agitated experiments. Raman results showed the static experiments were chaotic, especially during and shortly after manual sampling.

  19. Forecast model for the evaluation of economic resources employed in the health care of patients with HIV infection

    Directory of Open Access Journals (Sweden)

    Sacchi P

    2012-05-01

    Full Text Available Paolo Sacchi1, Savino FA Patruno1, Raffaele Bruno1, Serena Maria Benedetta Cima1, Pietro Previtali2, Alessia Franchini2, Luca Nicolini3, Carla Rognoni4, Lucia Sacchi5, Riccardo Bellazzi4, Gaetano Filice11Divisione di Malattie Infettive e Tropicali - Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; 2Università degli Studi di Pavia – Facoltà di Economia, Pavia, Italy; 3Controllo di Gestione Fondazione IRCCS Policlinico San Matteo di Pavia, Pavia, Italy; 4Dipartimento di Informatica e Sistemistica, Universita' degli Studi di Pavia, Pavia, Italy; 5Department of Information Systems and Computing, Brunel University, London, UKBackground and aims: The total health care cost for human immunodeficiency virus (HIV patients has constantly grown in recent years. To date, there is no information about how this trend will behave over the next few years. The aim of the present study is to define a pharmacoeconomic model for the forecast of the costs of a group of chronically treated patients followed over the period 2004–2009.Methods: A pharmacoeconomics model was built to describe the probability of transition among different health states and to modify the therapy over time. A Markov model was applied to evaluate the temporal evolution of the average cost. The health care resources exploited during hospitalization were analyzed by using an “activity-based costing” method.Results: The Markov model showed that the mean total cost, after an initial increase, tended to remain stable. A total of 20 clinical records were examined. The average daily cost for each patient was EUR 484.42, with a cost for admission of EUR 6781.88.Conclusion: The treatment of HIV infection in compliance with the guidelines is also effective from the payer perspective, as it allows a good health condition to be maintained and reduces the need and the costs of hospitalizations.Keywords: health care cost, HIV, Markov model, activity-based costing

  20. Fit of different functions to the individual deviations in random regression test day models for milk yield in dairy cattle

    Directory of Open Access Journals (Sweden)

    L.R. Schaeffer

    2010-04-01

    Full Text Available The shape of individual deviations of milk yield for dairy cattle from the fixed part of a random regression test day model (RRTDM was investigated. Data were 53,217 TD records for milk yield of 6,229 first lactation Canadian Holsteins in Ontario. Data were fitted with a model that included the fixed effects of herd-testdate, DIM interval nested within age and season of calving. Residuals of the model were then fitted with the following functions: Ali and Schaeffer 5 parameter model, fourth-order Legendre Polynomials, and cubic spline with three, four or five knots. Result confirm the great variability of shape that can be found when individual lactation are modeled. Cubic splines gave better fitting pe4rformances although together with a marked tendency to yield aberrant estimates at the edge of the lactation trajectory.

  1. Modeling Mode Choice Behavior Incorporating Household and Individual Sociodemographics and Travel Attributes Based on Rough Sets Theory

    Directory of Open Access Journals (Sweden)

    Long Cheng

    2014-01-01

    Full Text Available Most traditional mode choice models are based on the principle of random utility maximization derived from econometric theory. Alternatively, mode choice modeling can be regarded as a pattern recognition problem reflected from the explanatory variables of determining the choices between alternatives. The paper applies the knowledge discovery technique of rough sets theory to model travel mode choices incorporating household and individual sociodemographics and travel information, and to identify the significance of each attribute. The study uses the detailed travel diary survey data of Changxing county which contains information on both household and individual travel behaviors for model estimation and evaluation. The knowledge is presented in the form of easily understood IF-THEN statements or rules which reveal how each attribute influences mode choice behavior. These rules are then used to predict travel mode choices from information held about previously unseen individuals and the classification performance is assessed. The rough sets model shows high robustness and good predictive ability. The most significant condition attributes identified to determine travel mode choices are gender, distance, household annual income, and occupation. Comparative evaluation with the MNL model also proves that the rough sets model gives superior prediction accuracy and coverage on travel mode choice modeling.

  2. Multistate models for clustered duration data - An application to workplace effects on individual sickness absenteeism

    NARCIS (Netherlands)

    Lindeboom, Maarten; Kerkhofs, Marcel

    2000-01-01

    Sickness absenteeism figures show a relatively large amount of variation across firms and organizations, indicating substantial within-firm correlations between absenteeism records of individual workers. To study the role of firm-specific circumstances and workforce composition, we specify

  3. Towards a Personalised, Learning Style Based Collaborative Blended Learning Model with Individual Assessment

    OpenAIRE

    Ilona BÉRES; Tímea MAGYAR; Márta TURCSÁNYI-SZABÓ

    2012-01-01

    In this paper we aim to describe the process by which our personalised web-based collaborative teaching/learning methodology (CECIP - Collaboration - Evaluation - Critical thinking - Individual assessment - learner Profile) evolved originating from Vygotsky's theory and based on the (C) collaborative construction of student's knowledge, (E) developing evaluation and assessment skills, (C) developing critical thinking skills, (I) integrating individual evaluation and (P) generating learner pro...

  4. Equilibrium, kinetic and reactive transport models for Pu: employing numerical methods to uncover the nature of the intrinsic colloid

    International Nuclear Information System (INIS)

    Schwantes, Jon M.; Batchelor, Bill

    2000-01-01

    Future missions for the Department of Defense include processing plutonium for vitrification and conversion to mixed oxide fuels for commercial use. Such processing could result in the production of Pu-containing waste and unplanned releases of Pu to the environment. Some releases related to plutonium processing have occurred in the past. However, scientists are currently not able to explain the observed behavior of plutonium in natural systems. For example, classical filtration theory predicts that plutonium transport within groundwater should be limited to a few tens of meters. Experimental observations, however, show that plutonium is present in groundwater at distances orders of magnitude farther away from its source than predicted. Before adequate disposal practices can be designed for plutonium, its behavior in these systems must be better understood. The overall goal of this project is to develop equilibrium, kinetic and reactive transport models that describe the behavior of Pu in aqueous systems and to apply these models to natural and engineered systems

  5. High-order feature-based mixture models of classification learning predict individual learning curves and enable personalized teaching.

    Science.gov (United States)

    Cohen, Yarden; Schneidman, Elad

    2013-01-08

    Pattern classification learning tasks are commonly used to explore learning strategies in human subjects. The universal and individual traits of learning such tasks reflect our cognitive abilities and have been of interest both psychophysically and clinically. From a computational perspective, these tasks are hard, because the number of patterns and rules one could consider even in simple cases is exponentially large. Thus, when we learn to classify we must use simplifying assumptions and generalize. Studies of human behavior in probabilistic learning tasks have focused on rules in which pattern cues are independent, and also described individual behavior in terms of simple, single-cue, feature-based models. Here, we conducted psychophysical experiments in which people learned to classify binary sequences according to deterministic rules of different complexity, including high-order, multicue-dependent rules. We show that human performance on such tasks is very diverse, but that a class of reinforcement learning-like models that use a mixture of features captures individual learning behavior surprisingly well. These models reflect the important role of subjects' priors, and their reliance on high-order features even when learning a low-order rule. Further, we show that these models predict future individual answers to a high degree of accuracy. We then use these models to build personally optimized teaching sessions and boost learning.

  6. Firms' contribution to the internal and external employability of older employees: evidence from Germany.

    Science.gov (United States)

    Tisch, Anita

    2015-03-01

    In the examination of older employees' employability, one can distinguish between internal and external employability. Internal employability can be measured by individual employment stability, and external employability occurs when employees replace one employment relationship with another. Most studies focus on the personal skills and characteristics that are necessary to maintain employability. However, external factors also contribute to individual employability. Therefore, this study examines which organisational attributes of firms contribute to older employees' employability in Germany. Taking firm and individual characteristics into account, the results of discrete-time survival models show that in specific organisational structures, older employees have higher internal employability. Accordingly, older employees are more likely to maintain employment in the service sector and in recruiting organisations facing (skilled) labour shortages. However, the results also indicate that financially investing organisations facilitate early labour market exits. With regard to older employees' external employability, the results show only little evidence indicating an association between organisational attributes of firms and the likelihood of job change.

  7. Models of Individual Dietary Behavior Based on Smartphone Data: The Influence of Routine, Physical Activity, Emotion, and Food Environment.

    Directory of Open Access Journals (Sweden)

    Edmund Seto

    Full Text Available Smartphone applications (apps facilitate the collection of data on multiple aspects of behavior that are useful for characterizing baseline patterns and for monitoring progress in interventions aimed at promoting healthier lifestyles. Individual-based models can be used to examine whether behavior, such as diet, corresponds to certain typological patterns. The objectives of this paper are to demonstrate individual-based modeling methods relevant to a person's eating behavior, and the value of such approach compared to typical regression models.Using a mobile app, 2 weeks of physical activity and ecological momentary assessment (EMA data, and 6 days of diet data were collected from 12 university students recruited from a university in Kunming, a rapidly developing city in southwest China. Phone GPS data were collected for the entire 2-week period, from which exposure to various food environments along each subject's activity space was determined. Physical activity was measured using phone accelerometry. Mobile phone EMA was used to assess self-reported emotion/feelings. The portion size of meals and food groups was determined from voice-annotated videos of meals. Individual-based regression models were used to characterize subjects as following one of 4 diet typologies: those with a routine portion sizes determined by time of day, those with portion sizes that balance physical activity (energy balance, those with portion sizes influenced by emotion, and those with portion sizes associated with food environments.Ample compliance with the phone-based behavioral assessment was observed for all participants. Across all individuals, 868 consumed food items were recorded, with fruits, grains and dairy foods dominating the portion sizes. On average, 218 hours of accelerometry and 35 EMA responses were recorded for each participant. For some subjects, the routine model was able to explain up to 47% of the variation in portion sizes, and the energy

  8. Models of Individual Dietary Behavior Based on Smartphone Data: The Influence of Routine, Physical Activity, Emotion, and Food Environment.

    Science.gov (United States)

    Seto, Edmund; Hua, Jenna; Wu, Lemuel; Shia, Victor; Eom, Sue; Wang, May; Li, Yan

    2016-01-01

    Smartphone applications (apps) facilitate the collection of data on multiple aspects of behavior that are useful for characterizing baseline patterns and for monitoring progress in interventions aimed at promoting healthier lifestyles. Individual-based models can be used to examine whether behavior, such as diet, corresponds to certain typological patterns. The objectives of this paper are to demonstrate individual-based modeling methods relevant to a person's eating behavior, and the value of such approach compared to typical regression models. Using a mobile app, 2 weeks of physical activity and ecological momentary assessment (EMA) data, and 6 days of diet data were collected from 12 university students recruited from a university in Kunming, a rapidly developing city in southwest China. Phone GPS data were collected for the entire 2-week period, from which exposure to various food environments along each subject's activity space was determined. Physical activity was measured using phone accelerometry. Mobile phone EMA was used to assess self-reported emotion/feelings. The portion size of meals and food groups was determined from voice-annotated videos of meals. Individual-based regression models were used to characterize subjects as following one of 4 diet typologies: those with a routine portion sizes determined by time of day, those with portion sizes that balance physical activity (energy balance), those with portion sizes influenced by emotion, and those with portion sizes associated with food environments. Ample compliance with the phone-based behavioral assessment was observed for all participants. Across all individuals, 868 consumed food items were recorded, with fruits, grains and dairy foods dominating the portion sizes. On average, 218 hours of accelerometry and 35 EMA responses were recorded for each participant. For some subjects, the routine model was able to explain up to 47% of the variation in portion sizes, and the energy balance model was

  9. Energy levy and employment

    International Nuclear Information System (INIS)

    De Mooij, R.A.

    1993-01-01

    The employment in the Netherlands seems to be relatively vulnerable for an energy levy compared to other European countries. Therefore, implementation of an energy levy because of the environment demands a supporting policy for the employment. This can be realized by using the yield of the levy totally for the decrease of the tax burden on labour. An unbalanced distribution of incomes between the working population and the unemployed population must be taken for granted. Based on the general equilibrium model ENTAX (ENvironmental TAXation) for a small economy a number of factors, which can impact the cost effectiveness of a regulating energy levy, are discussed. Six countries (Netherlands, Belgium, Denmark, Germany, France and the United Kingdom) are compared regarding these factors. 4 tabs., 15 refs

  10. Gap models and their individual-based relatives in the assessment of the consequences of global change

    Science.gov (United States)

    Shugart, Herman H.; Wang, Bin; Fischer, Rico; Ma, Jianyong; Fang, Jing; Yan, Xiaodong; Huth, Andreas; Armstrong, Amanda H.

    2018-03-01

    Individual-based models (IBMs) of complex systems emerged in the 1960s and early 1970s, across diverse disciplines from astronomy to zoology. Ecological IBMs arose with seemingly independent origins out of the tradition of understanding the ecosystems dynamics of ecosystems from a ‘bottom-up’ accounting of the interactions of the parts. Individual trees are principal among the parts of forests. Because these models are computationally demanding, they have prospered as the power of digital computers has increased exponentially over the decades following the 1970s. This review will focus on a class of forest IBMs called gap models. Gap models simulate the changes in forests by simulating the birth, growth and death of each individual tree on a small plot of land. The summation of these plots comprise a forest (or set of sample plots on a forested landscape or region). Other, more aggregated forest IBMs have been used in global applications including cohort-based models, ecosystem demography models, etc. Gap models have been used to provide the parameters for these bulk models. Currently, gap models have grown from local-scale to continental-scale and even global-scale applications to assess the potential consequences of climate change on natural forests. Modifications to the models have enabled simulation of disturbances including fire, insect outbreak and harvest. Our objective in this review is to provide the reader with an overview of the history, motivation and applications, including theoretical applications, of these models. In a time of concern over global changes, gap models are essential tools to understand forest responses to climate change, modified disturbance regimes and other change agents. Development of forest surveys to provide the starting points for simulations and better estimates of the behavior of the diversity of tree species in response to the environment are continuing needs for improvement for these and other IBMs.

  11. Using plot experiments to test the validity of mass balance models employed to estimate soil redistribution rates from 137Cs and 210Pb(ex) measurements.

    Science.gov (United States)

    Porto, Paolo; Walling, Des E

    2012-10-01

    Information on rates of soil loss from agricultural land is a key requirement for assessing both on-site soil degradation and potential off-site sediment problems. Many models and prediction procedures have been developed to estimate rates of soil loss and soil redistribution as a function of the local topography, hydrometeorology, soil type and land management, but empirical data remain essential for validating and calibrating such models and prediction procedures. Direct measurements using erosion plots are, however, costly and the results obtained relate to a small enclosed area, which may not be representative of the wider landscape. In recent years, the use of fallout radionuclides and more particularly caesium-137 ((137)Cs) and excess lead-210 ((210)Pb(ex)) has been shown to provide a very effective means of documenting rates of soil loss and soil and sediment redistribution in the landscape. Several of the assumptions associated with the theoretical conversion models used with such measurements remain essentially unvalidated. This contribution describes the results of a measurement programme involving five experimental plots located in southern Italy, aimed at validating several of the basic assumptions commonly associated with the use of mass balance models for estimating rates of soil redistribution on cultivated land from (137)Cs and (210)Pb(ex) measurements. Overall, the results confirm the general validity of these assumptions and the importance of taking account of the fate of fresh fallout. However, further work is required to validate the conversion models employed in using fallout radionuclide measurements to document soil redistribution in the landscape and this could usefully direct attention to different environments and to the validation of the final estimates of soil redistribution rate as well as the assumptions of the models employed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. A method to employ the spatial organization of catchments into semi-distributed rainfall-runoff models

    Science.gov (United States)

    Oppel, Henning; Schumann, Andreas

    2017-08-01

    A distributed or semi-distributed deterministic hydrological model should consider the hydrologically most relevant catchment characteristics. These are heterogeneously distributed within a watershed but often interrelated and subject to a certain spatial organization which results in archetypes of combined characteristics. In order to reproduce the natural rainfall-runoff response the reduction of variance of catchment properties as well as the incorporation of the spatial organization of the catchment are desirable. In this study the width-function approach is utilized as a basic characteristic to analyse the succession of catchment characteristics. By applying this technique we were able to assess the context of catchment properties like soil or topology along the streamflow length and the network geomorphology, giving indications of the spatial organization of a catchment. Moreover, this information and this technique have been implemented in an algorithm for automated sub-basin ascertainment, which included the definition of zones within the newly defined sub-basins. The objective was to provide sub-basins that were less heterogeneous than common separation schemes. The algorithm was applied to two parameters characterizing the topology and soil of four mid-European watersheds. Resulting partitions indicated a wide range of applicability for the method and the algorithm. Additionally, the intersection of derived zones for different catchment characteristics could give insights into sub-basin similarities. Finally, a HBV96 case study demonstrated the potential benefits of modelling with the new subdivision technique.

  13. A method to employ the spatial organization of catchments into semi-distributed rainfall–runoff models

    Directory of Open Access Journals (Sweden)

    H. Oppel

    2017-08-01

    Full Text Available A distributed or semi-distributed deterministic hydrological model should consider the hydrologically most relevant catchment characteristics. These are heterogeneously distributed within a watershed but often interrelated and subject to a certain spatial organization which results in archetypes of combined characteristics. In order to reproduce the natural rainfall–runoff response the reduction of variance of catchment properties as well as the incorporation of the spatial organization of the catchment are desirable. In this study the width-function approach is utilized as a basic characteristic to analyse the succession of catchment characteristics. By applying this technique we were able to assess the context of catchment properties like soil or topology along the streamflow length and the network geomorphology, giving indications of the spatial organization of a catchment. Moreover, this information and this technique have been implemented in an algorithm for automated sub-basin ascertainment, which included the definition of zones within the newly defined sub-basins. The objective was to provide sub-basins that were less heterogeneous than common separation schemes. The algorithm was applied to two parameters characterizing the topology and soil of four mid-European watersheds. Resulting partitions indicated a wide range of applicability for the method and the algorithm. Additionally, the intersection of derived zones for different catchment characteristics could give insights into sub-basin similarities. Finally, a HBV96 case study demonstrated the potential benefits of modelling with the new subdivision technique.

  14. Development of a kinetic model and calculation of radiation dose estimates for sodium iodide-131I in athyroid individuals

    International Nuclear Information System (INIS)

    Rodriguez, M.

    1997-07-01

    The treatment for some thyroid carcinomas involves surgically removing the thyroid gland and administering the radiopharmaceutical Sodium iodide- 131 I (NaI). A diagnostic dose of NaI is given to the patient to determine if remnant tissue from the gland remains or larger doses are administered in order to treat the malignant tissue. Past research regarding NaI uptake and retention in euthyroid individuals (normal functioning thyroid) reveal that radioiodine concentrates mainly in the thyroid tissue and the remaining material is excreted from the body. The majority of radioiodine in athyroid (without thyroid) individuals is also eliminated from the body; however, there has been recent evidence of a long-term retention phase for individuals with no radioiodine concentrating tissue. The general purpose of this study was to develop a kinetic model and estimate the absorbed dose to athyroid individuals regarding the distribution and retention of NaI

  15. Development of a Case Formulation Model for Individuals Who Have Viewed, Distributed, and/or Shared Child Sexual Exploitation Material.

    Science.gov (United States)

    Merdian, Hannah L; Perkins, Derek E; Dustagheer, Elspeth; Glorney, Emily

    2018-01-01

    Increases in the number of arrests of individuals who download or distribute Child Sexual Exploitation Material (CSEM) have highlighted a need to further understand the offending pathways of this offender group. This article describes the development of an aetiological model specific to CSEM offending. Individuals who had viewed, distributed, and/or shared CSEM ( n = 20) were interviewed regarding their life and sexual history, relationships, substance use, offending details, and circumstances leading to their CSEM offending, resulting in seven superordinate themes: Developmental Context, Individual Propensities (risk-related and risk-protective) and Psychological Vulnerabilities, Personal Circumstances, Permission-Giving Thoughts, Internet Environment and Behaviour, Evaluation of Consequences for the Individual, and Desistance. These themes were combined into a case formulation tool specific for CSEM offending behaviour, with the aim of providing systematic guidance for assessment and treatment providers.

  16. Individualized 3D printed model-assisted posterior screw fixation for the treatment of craniovertebral junction abnormality: a retrospective study.

    Science.gov (United States)

    Gao, Fangyou; Wang, Qu; Liu, Chuangxi; Xiong, Bing; Luo, Tao

    2017-07-01

    OBJECTIVE This study was undertaken to evaluate the feasibility and efficacy of individualized 3D printed model-assisted posterior internal fixation in treating craniovertebral junction (CVJ) abnormalities. METHODS Forty-four patients (19 males and 25 females; mean age 36.5 ± 9.2 years, range 11-62 years; symptom duration 1 month-15 years) with a CVJ abnormality who were admitted to the authors' institution between April 2010 and April 2015 were retrospectively studied. The individualized 3D printed model of the CVJ was produced based on the individual CT data by use of 3D printing technology. The posterior internal fixation was simulated on the model to obtain data for individual patients, which were then used for intraoperative assistance. One-stage posterior decompression combined with internal fixation was performed. The results were evaluated using the Japanese Orthopaedic Association (JOA) scale, atlanto-dens interval (ADI), and cervicomedullary angle (CMA). The patients underwent follow-up and outcomes were evaluated using CT, MRI, and the JOA scale score. The comparison between preoperative and postoperative JOA scale scores was done using a paired t-test. RESULTS Thirty-eight individualized 3D printed models were successfully built. The 38 patients underwent successful posterior internal fixation performed with the assistance of 3D printed models. In the 6 patients without an individualized printed model (i.e., the patients who underwent surgery before 3D printed modeling was available at the authors' institution), the pedicle screw was inserted incorrectly into the transverse foramen in 2 patients and inserted incorrectly into the vertebral canal in 1 patient. All patients were observed for a mean of 26 months (range 3-52 months). The postoperative JOA scale scores for all patients significantly improved from the preoperative scores. Among the 41 patients treated with atlantoaxial distraction reduction, postoperative MRI and CT showed complete reduction

  17. Relationship between US Societal Fatality Risk per Vehicle Miles of Travel and Mass, for Individual Vehicle Models over Time (Model Year)

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, Tom P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Technologies Area. Building Technology and Urban Systems Division

    2016-07-27

    This report presents a new approach to analyze the relationship between vehicle mass and risk: tracking fatality risk by vehicle model year and mass, for individual vehicle models. This approach is appealing as it greatly minimizes the influence of driver characteristics and behavior, and crash circumstances, on fatality risk. However, only the most popular vehicle models, with the largest number of fatalities, can be analyzed in this manner. While the analysis of all vehicle models of a given type suggests that there is a relationship between increased mass and fatality risk, analysis of the ten most popular four-door car models separately suggests that this relationship is weak: in many cases when the mass of a specific vehicle model is increased societal fatality risk is unchanged or even increases. These results suggest that increasing the mass of an individual vehicle model does not necessarily lead to decreased societal fatality risk.

  18. Modeling individual exposures to ambient PM2.5 in the diabetes and the environment panel study (DEPS).

    Science.gov (United States)

    Breen, Michael; Xu, Yadong; Schneider, Alexandra; Williams, Ronald; Devlin, Robert

    2018-06-01

    Air pollution epidemiology studies of ambient fine particulate matter (PM 2.5 ) often use outdoor concentrations as exposure surrogates, which can induce exposure error. The goal of this study was to improve ambient PM 2.5 exposure assessments for a repeated measurements study with 22 diabetic individuals in central North Carolina called the Diabetes and Environment Panel Study (DEPS) by applying the Exposure Model for Individuals (EMI), which predicts five tiers of individual-level exposure metrics for ambient PM 2.5 using outdoor concentrations, questionnaires, weather, and time-location information. Using EMI, we linked a mechanistic air exchange rate (AER) model to a mass-balance PM 2.5 infiltration model to predict residential AER (Tier 1), infiltration factors (F inf_home , Tier 2), indoor concentrations (C in , Tier 3), personal exposure factors (F pex , Tier 4), and personal exposures (E, Tier 5) for ambient PM 2.5 . We applied EMI to predict daily PM 2.5 exposure metrics (Tiers 1-5) for 174 participant-days across the 13 months of DEPS. Individual model predictions were compared to a subset of daily measurements of F pex and E (Tiers 4-5) from the DEPS participants. Model-predicted F pex and E corresponded well to daily measurements with a median difference of 14% and 23%; respectively. Daily model predictions for all 174 days showed considerable temporal and house-to-house variability of AER, F inf_home , and C in (Tiers 1-3), and person-to-person variability of F pex and E (Tiers 4-5). Our study demonstrates the capability of predicting individual-level ambient PM 2.5 exposure metrics for an epidemiological study, in support of improving risk estimation. Copyright © 2018. Published by Elsevier B.V.

  19. Nonlinear joint models for individual dynamic prediction of risk of death using Hamiltonian Monte Carlo: application to metastatic prostate cancer

    Directory of Open Access Journals (Sweden)

    Solène Desmée

    2017-07-01

    Full Text Available Abstract Background Joint models of longitudinal and time-to-event data are increasingly used to perform individual dynamic prediction of a risk of event. However the difficulty to perform inference in nonlinear models and to calculate the distribution of individual parameters has long limited this approach to linear mixed-effect models for the longitudinal part. Here we use a Bayesian algorithm and a nonlinear joint model to calculate individual dynamic predictions. We apply this approach to predict the risk of death in metastatic castration-resistant prostate cancer (mCRPC patients with frequent Prostate-Specific Antigen (PSA measurements. Methods A joint model is built using a large population of 400 mCRPC patients where PSA kinetics is described by a biexponential function and the hazard function is a PSA-dependent function. Using Hamiltonian Monte Carlo algorithm implemented in Stan software and the estimated population parameters in this population as priors, the a posteriori distribution of the hazard function is computed for a new patient knowing his PSA measurements until a given landmark time. Time-dependent area under the ROC curve (AUC and Brier score are derived to assess discrimination and calibration of the model predictions, first on 200 simulated patients and then on 196 real patients that are not included to build the model. Results Satisfying coverage probabilities of Monte Carlo prediction intervals are obtained for longitudinal and hazard functions. Individual dynamic predictions provide good predictive performances for landmark times larger than 12 months and horizon time of up to 18 months for both simulated and real data. Conclusions As nonlinear joint models can characterize the kinetics of biomarkers and their link with a time-to-event, this approach could be useful to improve patient’s follow-up and the early detection of most at risk patients.

  20. An individual-based evolving predator-prey ecosystem simulation using a fuzzy cognitive map as the behavior model

    OpenAIRE

    Gras , Robin; Devaurs , Didier; Wozniak , Adrianna; Aspinall , Adam

    2009-01-01

    International audience; This paper presents an individual-based predator-prey model with, for the first time, each agent behavior being modeled by a Fuzzy Cognitive Map (FCM), allowing the evolution of the agent behavior through the epochs of the simulation. The FCM enables the agent to evaluate its environment (e.g., distance to predator/prey, distance to potential breeding partner, distance to food, energy level), its internal state (e.g., fear, hunger, curiosity) with memory and choosing s...