Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Statistics

  • analysis statistics
  • basic statistics
  • bayesian statistics
  • chi-square statistics
  • correlation statistics
  • counting statistics
  • crystallographic statistics
  • death statistics
  • descriptive statistics
  • diversity statistics
  • economic statistics
  • episode statistics
  • health statistics
  • hospital episode statistics
  • inferential statistics
  • intensity statistics
  • kappa statistics
  • medical statistics
  • mortality statistics
  • multivariate statistics
  • national statistics
  • non-parametric statistics
  • nonparametric statistics
  • official statistics
  • order statistics
  • other statistics
  • population statistics
  • proposed test statistics
  • score statistics
  • second-order statistics
  • spatial statistics
  • sufficient statistics
  • summary statistics
  • survival analysis statistics
  • test statistics
  • third-order statistics
  • verification statistics
  • vital statistics

  • Terms modified by Statistics

  • statistics canada
  • statistics data
  • statistics netherlands
  • statistics show
  • statistics used

  • Selected Abstracts


    EVOLUTION, Issue 10 2009
    Brittny Calsbeek
    A central assumption of quantitative genetic theory is that the breeder's equation (R=GP,1S) accurately predicts the evolutionary response to selection. Recent studies highlight the fact that the additive genetic variance,covariance matrix (G) may change over time, rendering the breeder's equation incapable of predicting evolutionary change over more than a few generations. Although some consensus on whether G changes over time has been reached, multiple, often-incompatible methods for comparing G matrices are currently used. A major challenge of G matrix comparison is determining the biological relevance of observed change. Here, we develop a "selection skewers"G matrix comparison statistic that uses the breeder's equation to compare the response to selection given two G matrices while holding selection intensity constant. We present a bootstrap algorithm that determines the significance of G matrix differences using the selection skewers method, random skewers, Mantel's and Bartlett's tests, and eigenanalysis. We then compare these methods by applying the bootstrap to a dataset of laboratory populations of Tribolium castaneum. We find that the results of matrix comparison statistics are inconsistent based on differing a priori goals of each test, and that the selection skewers method is useful for identifying biologically relevant G matrix differences. [source]

    Call for Papers for a Special Issue of the International Statistical Review on ENERGY STATISTICS

    Ali S. Hadi Editor-in-Chief
    No abstract is available for this article. [source]


    Article first published online: 9 OCT 200
    No abstract is available for this article. [source]


    Article first published online: 9 OCT 200
    No abstract is available for this article. [source]


    Anthony G. Pakes
    Summary Limit theorems are obtained for the numbers of observations in a random sample that fall within a left-hand or right-hand neighbourhood of the,kth order statistic. The index,k,can be fixed, or tend to infinity as the sample size increases unboundedly. In essence, the proofs are applications of the classical Poisson and De Moivre,Laplace theorems. [source]


    Mariusz Bieniek
    Summary We investigate the problem of characterizations of distributions by regressions of generalized order statistics (GOSs) based on a continuous distribution function F. We show that F is uniquely determined if the regressions of a GOS given two other consecutive GOSs are known. [source]

    Statistics and impact factor for Contact Dermatitis 2005

    CONTACT DERMATITIS, Issue 3 2006
    T. Menné
    No abstract is available for this article. [source]

    FS07.2 Occupational contact dermatitis and workers' compensation

    CONTACT DERMATITIS, Issue 3 2004
    Kathryn Frowen
    Statistics for occupational contact dermatitis (OCD) in Australia are gathered from workers' compensation (WC) data and research has indicated that occurrence is underestimated by as much as 400%. This study investigated reasons which might influence decisions whether to claim WC or not. A questionnaire was posted to 168 individuals diagnosed with significantly work related OCD at a specialised occupational dermatology clinic, therefore fulfilling valid claim criteria under the WC scheme operating in the state of Victoria. 70 completed responses were analysed. Ages ranged from 18,65 and only 40% had claimed workers' compensation, with those under 45 y less likely to claim. Females were significantly (P < 0.05) less likely to claim, as were respondents who had dermatitis present for less than 6 months. At the time of diagnosis, 37% of respondents were health care workers, 10% hairdressers, 7% food handlers, and 29% worked in hospitals, 24% manufacturing, 10% hairdressing salons, and 7% each vehicle maintenance, food service and trades. 31% no longer worked for the same employer, however 90% of respondents were still employed. Those who did not claim WC lost less time from work than those who claimed, but more non-claimants still had skin problems quite often or constantly than did claimants. 28.6% of non-claimants had all or some of their medical and/or lost time costs paid by their employer, and only 18% of claimants had all of their costs paid by their employer or WC insurer. Although the sample size was small, interesting data was also obtained from the qualitative responses. [source]

    Reasons for variation in coverage in the NHS cervical screening programme

    CYTOPATHOLOGY, Issue 6 2001
    C. E. McGAHAN
    Reasons for variation in coverage in the NHS cervical screening programme In order to investigate reasons for variation in coverage of cervical screening, data from standard Department of Health returns were obtained for all Health Authorities for 1998/1999. Approximately 80% of the variation between health authorities is explained by differences in age distribution and area classification. Considerable differences between Health Authority and Office of National Statistics (ONS) population figures in City and Urban (London) areas for the age group 25,29 years and for City (London) for age group 30,34 years, suggest an effect of list inflation in these groups. Coverage as a performance indicator may be more accurately represented using the age range 35,64 years. Using this narrower age range, the percentage of health authorities meeting the 80% 5-year coverage target increases from 87% to 90%. [source]

    Classroom Integration of Statistics and Management Science Via Forecasting

    M. David Albritton
    First page of article [source]

    Risk factors related to traumatic dental injuries in Brazilian schoolchildren

    Evelyne Pessoa Soriano
    Abstract,,, The aim of this pilot study was to analyse whether overjet, lip coverage and obesity represented risk factors associated with the occurrence of dental trauma in the permanent anterior teeth of schoolchildren in Recife, Brazil. It included a random sample of 116 boys and girls aged 12 years, attending both public and private schools. Data was collected through clinical examinations and interviews. Dental trauma was classified according to Andreasen's criteria (1994). Overjet was considered as risk factor when it presented values higher than 5 mm. Lip coverage was classified as adequate or inadequate, while obesity was considered according to National Center for Health Statistics (NCHS) procedures for the assessment of nutritional status. The prevalence of dental injuries was 23.3%. Boys experienced more injuries than girls, 30 and 16.1%, respectively (P > 0.05). There was a statistically significant difference between traumatic dental injuries and overjet (P < 0.05) and between traumatic dental injuries and lip coverage (P = 0.000). No statistical significant differences were found when obesity and dental trauma were analysed (P < 0.05). It was concluded that boys from lower social strata attending public schools, presenting an overjet size greater than 5 mm and an inadequate lip coverage, were more likely to have traumatic dental injuries in Recife, Brazil. Obesity was not a risk factor for dental trauma in this sample. [source]

    Diagnostic utility of the Quick Inventory of Depressive Symptomatology (QIDS-C16 and QIDS-SR16) in the elderly

    P. M. Doraiswamy
    Doraiswamy PM, Bernstein IH, Rush AJ, Kyutoku Y, Carmody TJ, Macleod L, Venkatraman S, Burks M, Stegman D, Witte B, Trivedi MH. Diagnostic utility of the Quick Inventory of Depressive Symptomatology (QIDS-C16 and QIDS-SR16) in the elderly. Objective:, To evaluate psychometric properties and comparability ability of the Montgomery-Åsberg Depression Rating Scale (MADRS) vs. the Quick Inventory of Depressive Symptomatology,Clinician-rated (QIDS-C16) and Self-report (QIDS-SR16) scales to detect a current major depressive episode in the elderly. Method:, Community and clinic subjects (age ,60 years) were administered the Mini-International Neuropsychiatric Interview (MINI) for DSM-IV and three depression scales randomly. Statistics included classical test and Samejima item response theories, factor analyzes, and receiver operating characteristic methods. Results:, In 229 elderly patients (mean age = 73 years, 39% male, 54% current depression), all three scales were unidimensional and with nearly equal Cronbach , reliability (0.85,0.89). Each scale discriminated persons with major depression from the non-depressed, but the QIDS-C16 was slightly more accurate. Conclusion:, All three tests are valid for detecting geriatric major depression with the QIDS-C16 being slightly better. Self-rated QIDS-SR16 is recommended as a screening tool as it is least expensive and least time consuming. [source]

    Trends in Pediatric Melanoma Mortality in the United States, 1968 through 2004

    BACKGROUND AND OBJECTIVE Mortality from melanoma in children is a poorly understood and controversial problem in dermatology. There is paucity of research into this important public health dilemma. The purpose of this study was to characterize pediatric melanoma mortality in the United States and to evaluate trends over time. METHODS AND MATERIALS Deaths were derived from a database of more than 75 million records of the U.S. Center for National Health Statistics based on routine death certification. Information on age, race, gender, and geographic location was available for years 1968 through 2004. RESULTS During the 37-year period, there were 643 deaths attributed to melanoma in children under 20 years of age in the United States, an average of 18 per year. The overall age-adjusted mortality rate for melanoma in children was 2.25 deaths per year (per 10 million at-risk individuals). Mortality rates were strongly associated with age. In the oldest age group (age 15,19 years) the mortality rate was approximately an order of magnitude 8,18 times higher compared to younger age groups. Mortality among males was 25% higher than females. Mortality rates for white children were more than twice as high as black children. Overall mortality from melanoma in children declined steadily from 1968 to 2004. The highest mortality rates were observed in Idaho, Nevada, Arizona, and New Mexico. CONCLUSIONS Although mortality from melanoma among children in the United State is low, the magnitude of the public health burden from this preventable cause of death is substantial. In contrast to results of studies suggesting that the incidence of melanoma may be rising in children and adolescents, the data suggest that mortality in these groups may be falling. Additional study is warranted to further characterize and ultimately reduce mortality from childhood melanoma. [source]

    The definition of opioid-related deaths in Australia: implications for surveillance and policy

    Abstract The reported number of deaths caused by opioid use depends on the definition of an opioid-related death. In this study, we used Australian Bureau of Statistics (ABS) mortality data to illustrate how choice of classification codes used to record cause of death can impact on the statistics reported for national surveillance of opioid deaths. Using International Classification of Diseases version 10 (ICD-10) codes from ABS mortality data 1997,2002, we examined all deaths where opioids were reported as a contributing or underlying cause. For the 6-year period there was a total of 5839 deaths where opioids were reported. Three possible surveillance definitions of accidental opioid-related deaths were examined, and compared to the total number of deaths where opioids were reported for each year. Age restrictions, often placed on surveillance definitions, were also examined. As expected, the number of deaths was higher with the more inclusive definitions. Trends in deaths were found to be similar regardless of the definition used; however, a comparison between Australian states revealed up to a twofold difference in the absolute numbers of accidental opioid-related deaths, depending on the definition. Any interpretation of reported numbers of opioid deaths should specify any restrictions placed on the data, and describe the implications of definitions used. [source]

    Tidal estuary width convergence: Theory and form in North Australian estuaries

    Gareth Davies
    Abstract In order to better understand the relations between tidal estuary shape and geomorphic processes, the width profiles of 79 tidal channels from within 30 estuaries in northern Australia have been extracted from LANDSAT 5 imagery using GIS. Statistics describing the shape and width convergence of individual channels and entire estuaries (which can contain several channels) are analysed along with proxies for the tidal range and fluvial inputs of the estuaries in question. The width profiles of most individual channels can be reasonably approximated with an exponential curve, and this is also true of the width profiles of estuaries. However, the shape of this exponential width profile is strongly related to the mouth width of the system. Channels and estuaries with larger mouths generally exhibit a more pronounced ,funnel shape' than those with narrower mouths, reflecting the hydrodynamic importance of the distance over which the channel or estuarine width converges. At the estuarine scale, this ,convergence length' also tends to be higher in estuaries which have larger catchments relative to their size. No clear relation between the estuarine width convergence length and tidal range could be discerned within the Northern Australian estuaries although, when these data are combined with data from other studies, a weak relationship emerges. Copyright © 2010 John Wiley & Sons, Ltd. [source]

    Instructional Tools in Educational Measurement and Statistics (ITEMS) for School Personnel: Evaluation of Three Web-Based Training Modules

    Rebecca Zwick
    In the current No Child Left Behind era, K-12 teachers and principals are expected to have a sophisticated understanding of standardized test results, use them to improve instruction, and communicate them to others. The goal of our project, funded by the National Science Foundation, was to develop and evaluate three Web-based instructional modules in educational measurement and statistics to help school personnel acquire the "assessment literacy" required for these roles. Our first module, "What's the Score?" was administered in 2005 to 113 educators who also completed an assessment literacy quiz. Viewing the module had a small but statistically significant positive effect on quiz scores. Our second module, "What Test Scores Do and Don't Tell Us," administered in 2006 to 104 educators, was even more effective, primarily among teacher education students. In evaluating our third module, "What's the Difference?" we were able to recruit only 33 participants. Although those who saw the module before taking the quiz outperformed those who did not, results were not statistically significant. Now that the research phase is complete, all ITEMS instructional materials are freely available on our Website. [source]

    Statistics for spatial functional data: some recent contributions

    ENVIRONMETRICS, Issue 3-4 2010
    P. Delicado
    Abstract Functional data analysis (FDA) is a relatively new branch in statistics. Experiments where a complete function is observed for each individual give rise to functional data. In this work we focus on the case of functional data presenting spatial dependence. The three classic types of spatial data structures (geostatistical data, point patterns, and areal data) can be combined with functional data as it is shown in the examples of each situation provided here. We also review some contributions in the literature on spatial functional data. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Trends in Parkinson's disease related mortality in England and Wales, 1993,2006

    A. Q. N. Mylne
    Background:, This paper describes changes in Parkinson's disease (PD) mortality in England and Wales between 1993 and 2006 using all information on death certificates. Methods:, Information on deaths was obtained from the Office for National Statistics. Mortality rates for any mention of PD on death certificates were directly age-standardized using the European standard population. Average yearly changes in mortality rates were estimated using linear regression. The underlying cause of death on death certificates where PD was mentioned was examined by sex and calendar period. Results:, Male PD age-standardized mortality rates for any mention of PD decreased from 15.0 to 11.7 per 100 000 between 1993 and 2006. Female PD mortality rates fell from 6.3 to 4.9 per 100 000. Decreases were greater for older age-groups. The proportion of deaths with PD recorded as the underlying cause increased by 50% in 2001 following implementation of the 10th revision of the International Classification of Diseases (ICD). Conclusion:, Parkinson's disease mortality rates in England and Wales are decreasing, especially for men and for older age-groups. Because of data limitations we are unable to ascertain whether the decrease of PD recorded on death certificates is because of a reduction in PD incidence, or to improved survival for PD patients resulting from advancements in PD treatments or to improvements in general medical care. The dramatic increase in PD as the underlying cause of death following ICD revision in 2001 demonstrates the dangers of using underlying cause of death to investigate mortality trends without being aware of the potential for artifacts. [source]

    Advanced Statistics:Statistical Methods for Analyzing Cluster and Cluster-randomized Data

    Robert L. Wears MD
    Abstract. Sometimes interventions in randomized clinical trials are not allocated to individual patients, but rather to patients in groups. This is called cluster allocation, or cluster randomization, and is particularly common in health services research. Similarly, in some types of observational studies, patients (or observations) are found in naturally occurring groups, such as neighborhoods. In either situation, observations within a cluster tend to be more alike than observations selected entirely at random. This violates the assumption of independence that is at the heart of common methods of statistical estimation and hypothesis testing. Failure to account for the dependence between individual observations and the cluster to which they belong can have profound implications on the design and analysis of such studies. Their p-values will be too small, confidence intervals too narrow, and sample size estimates too small, sometimes to a dramatic degree. This problem is similar to that caused by the more familiar "unit of analysis error" seen when observations are repeated on the same subjects, but are treated as independent. The purpose of this paper is to provide an introduction to the problem of clustered data in clinical research. It provides guidance and examples of methods for analyzing clustered data and calculating sample sizes when planning studies. The article concludes with some general comments on statistical software for cluster data and principles for planning, analyzing, and presenting such studies. [source]

    Oral Impacts on Daily Performance in Norwegian adults: validity, reliability and prevalence estimates

    A. N. Åstrøm
    The Oral Impacts on Daily Performance (OIDP) instrument was translated into Norwegian and reviewed for cultural and conceptual equivalence by a group of bilingual academics. A sample of employees from the University of Bergen completed the Norwegian OIDP frequency questionnaire twice. A total of 173 and 108 subjects participated in the first and the second administration, respectively, of this questionnaire. A two-stage proportionate random sample, comprising 2,000 residents (age-range 16,79 yr), was drawn from the national population register by the Central Bureau of Statistics. Information became available for 1,309 persons who completed telephone interviews. The Norwegian OIDP preserved the overall concept of the English version. Test,retest reliability, in terms of Cohen's kappa, was 0.65, and Cronbach's alpha was high (, 0.80). In both samples, variations in the OIDP scores were apparent in relation to self-reported oral health and number of remaining teeth, supporting construct and criterion validity of the inventory. Only three of the OIDP interviews were discarded, which supports face validity. A total of 18.3% confirmed that they had at least one oral impact. Age-specific rates were 17.5%, 19.0%, 17.9% and 18.4% among 16,24, 24,44, 45,66 and 67,79-yr-old participants. The satisfactory psychometric properties provide evidence for the cross-cultural use of the OIDP. The presence of a distinct floor effect indicates poor sensitivity of the OIDP to detect improvements of oral health-related quality of life at a population level. Prevalence estimates were low, suggesting that the current oral health status has little impact on the daily performance of the Norwegian adult population. [source]

    In Situ Observation of Dynamic Recrystallization in the Bulk of Zirconium Alloy,

    Klaus-Dieter Liss
    Dynamic recrystallization and related effects have been followed in situ and in real time while a metal undergoes rapid thermo-mechanical processing. Statistics and orientation correlations of embedded/bulk material grains were deduced from two-dimensional X-ray diffraction patterns and give deep insight into the formation of the microstructure. Applications are relevant in materials design, simulation, and in geological systems. [source]

    Graduate Research Completed in Family and Consumer Sciences During 2008

    Bernice Dodor
    Contacts were made with 50 individuals at 35 colleges and universities during the spring of 2009 to gather information on the graduate research completed in Family and Consumer Sciences units during 2008. Nineteen institutions reported a total of 329 graduate research titles. During that same time, 2020 master's degrees and 377 doctor's degrees were granted in Family and Consumer Sciences according to data available from the National Center for Education Statistics. [source]


    Ralph Kober
    This study examines the usefulness of three accounting systems (cash, Generally Accepted Accounting Principles (GAAP) accrual, and Government Finance Statistics (GFS) accrual) for public sector decision-making. From a survey of internal users, external users, and preparers in Australia, we find that GAAP accrual information is perceived to be relatively more useful and understandable than the other two systems for most decisions examined. The relatively higher ratings for GAAP accrual information differ from earlier studies and may reflect an experience or familiarity effect whereby perceptions of usefulness are enhanced because respondents have become more used to the system. This effect might also explain the lower ratings for GFS accrual. [source]

    Affected-sib-pair test for linkage based on constraints for identical-by-descent distributions corresponding to disease models with imprinting,

    Michael Knapp
    Abstract Holmans' possible triangle test for affected sib pairs has proven to be a powerful tool for linkage analysis. This test is a likelihood-ratio test for which maximization is restricted to the set of possible sharing probabilities. Here, we extend the possible triangle test to take into account genomic imprinting, which is also known as parent-of-origin effect. While the classical test without imprinting looks at whether affected sib pairs share 0, 1, or 2 alleles identical-by-descent, the likelihood-ratio test allowing for imprinting further distinguishes whether the sharing of exactly one allele is through the father or mother. Thus, if the disease gene is indeed subject to imprinting, the extended test presented here can take into account that affecteds will have inherited the mutant allele preferentially from one particular parent. We calculate the sharing probabilities at a marker locus linked to a disease susceptibility locus. Using our formulation, the constraints on these probabilities given by Dudoit and Speed ([1999] Statistics in Genetics; New York: Springer) can easily be verified. Next, we derive the asymptotic distribution of the restricted likelihood-ratio test statistic under the null hypothesis of no linkage, and give LOD-score criteria for various test sizes. We show, for various disease models, that the test allowing for imprinting has significantly higher power to detect linkage if imprinting is indeed present, at the cost of only a small reduction in power in case of no imprinting. Altogether, unlike many methods currently available, our novel model-free sib-pair test adequately models the epigenetic parent-of-origin effect, and will hopefully prove to be a useful tool for the genetic mapping of complex traits. © 2004 Wiley-Liss, Inc. [source]

    Impacts and Wider Impacts on Statistics

    Ganapati P. Patil
    The article discusses impacts and wider impacts on statistics of the seminal 1969 Cliff-Ord article on the problem of spatial autocorrelation published in London Papers in Regional Science. [source]

    Human Capital in Remote and Rural Australia: The Role of Graduate Migration

    GROWTH AND CHANGE, Issue 2 2010
    ABSTRACT In this paper we examine the spatial employment patterns of Australia's university graduates in nonurban locations. Using a 2006 data set recording the employment status of 65,661 university graduates 6 months after their graduation we examine how the personal and human capital characteristics of the individual university graduate affect the type of rural location into which he or she enters for employment purposes. The importance of identifying which types of graduates work where is essential for our understanding of the forces that are currently shaping the spatial distribution of human capital across Australia's regions. In order to do this we allocate postcode-based data of graduate employment to one of five remoteness classes, as defined by the Australian Bureau of Statistics, that allow us to distinguish between different degrees of rurality. The postcode data are used to associate the ways in which the human capital characteristics of the graduate in terms of the types of university degrees awarded and the universities attended, as well as the personal characteristics of the graduate, are related to the degrees of rurality in his or her employment outcomes. [source]

    Spatial Agglomeration, Technological Innovations, and Firm Productivity: Evidence from Italian Industrial Districts

    GROWTH AND CHANGE, Issue 3 2008
    ABSTRACT The aim of this paper is to analyse the impact on firms' productivity of innovative activities and agglomeration effects among firms belonging to Marshallian industrial districts and the possible joint effect of these two forces. We study a sample of 2,821 firms active in the Italian manufacturing industry in the period 1992,1995. Our analysis uses an original data set based on three different Istituto Nazionale di Statistica statistical sources,Community Innovation Survey, Archivio Statistico delle Imprese Attive (Italian Business Register), and Sistema dei Conti delle Imprese (Italian Structural Business Statistics),to estimate an "augmented" Cobb-Douglas production function to account for the impact of technological innovations and district-specific agglomeration effects on a firm's productivity growth. Our data set allows us to distinguish between product and process innovations, thus, through econometric analysis, we hope to achieve a better understanding of which of these two types of innovative activities benefits most from participation in an industrial district. Our empirical results show that belonging to an industrial district and making product innovations are key factors in the productivity growth of firms and that product innovations appear to have a greater effect on the economic performance of district rather than non-district firms. [source]

    Exploring the relationship between white matter and gray matter damage in early primary progressive multiple sclerosis: An in vivo study with TBSS and VBM

    HUMAN BRAIN MAPPING, Issue 9 2009
    Benedetta Bodini
    Abstract We investigated the relationship between the damage occurring in the brain normal-appearing white matter (NAWM) and in the gray matter (GM) in patients with early Primary Progressive multiple sclerosis (PPMS), using Tract-Based Spatial Statistics (TBSS) and an optimized voxel-based morphometry (VBM) approach. Thirty-five patients with early PPMS underwent diffusion tensor and conventional imaging and were clinically assessed. TBSS and VBM were employed to localize regions of lower fractional anisotropy (FA) and lower GM volume in patients compared with controls. Areas of anatomical and quantitative correlation between NAWM and GM damage were detected. Multiple regression analyses were performed to investigate whether NAWM FA or GM volume of regions correlated with clinical scores independently from the other and from age and gender. In patients, we found 11 brain regions that showed an anatomical correspondence between reduced NAWM FA and GM atrophy; of these, four showed a quantitative correlation (i.e., the right sensory motor region with the adjacent corticospinal tract, the left and right thalamus with the corresponding thalamic radiations and the left insula with the adjacent WM). Either the NAWM FA or the GM volume in each of these regions correlated with disability. These results demonstrate a link between the pathological processes occurring in the NAWM and in the GM in PPMS in specific, clinically relevant brain areas. Longitudinal studies will determine whether the GM atrophy precedes or follows the NAWM damage. The methodology that we described may be useful to investigate other neurological disorders affecting both the WM and the GM. Hum Brain Mapp 2009. © 2009 Wiley-Liss, Inc. [source]

    Toward brain correlates of natural behavior: fMRI during violent video games

    HUMAN BRAIN MAPPING, Issue 12 2006
    Klaus Mathiak
    Abstract Modern video games represent highly advanced virtual reality simulations and often contain virtual violence. In a significant amount of young males, playing video games is a quotidian activity, making it an almost natural behavior. Recordings of brain activation with functional magnetic resonance imaging (fMRI) during gameplay may reflect neuronal correlates of real-life behavior. We recorded 13 experienced gamers (18,26 years; average 14 hrs/week playing) while playing a violent first-person shooter game (a violent computer game played in self-perspective) by means of distortion and dephasing reduced fMRI (3 T; single-shot triple-echo echo-planar imaging [EPI]). Content analysis of the video and sound with 100 ms time resolution achieved relevant behavioral variables. These variables explained significant signal variance across large distributed networks. Occurrence of violent scenes revealed significant neuronal correlates in an event-related design. Activation of dorsal and deactivation of rostral anterior cingulate and amygdala characterized the mid-frontal pattern related to virtual violence. Statistics and effect sizes can be considered large at these areas. Optimized imaging strategies allowed for single-subject and for single-trial analysis with good image quality at basal brain structures. We propose that virtual environments can be used to study neuronal processes involved in semi-naturalistic behavior as determined by content analysis. Importantly, the activation pattern reflects brain-environment interactions rather than stimulus responses as observed in classical experimental designs. We relate our findings to the general discussion on social effects of playing first-person shooter games. Hum Brain Mapp, 2006. © 2006 Wiley-Liss, Inc. [source]

    Health Care and Pension Benefits for Construction Workers: TheRole of Prevailing Wage Laws Health Care and Pension Benefits for Construction Workers

    Jeffrey S. Petersen
    This article examines the affect of state prevailing wage laws (PWLs) on the amount and mix of wages and benefits paid to construction workers. PWLs require contractors who win bids on state-financed construction projects to pay compensation rates equivalent to those prevailing in local construction markets. During 1982-1992, 6 states repealed their PWLs, 9 states who never had a PWL did not enact one, and 32 states kept their PWLs. Data from the Form 5500 series, the Census of Construction Industries, the Current Employment Statistics, and the Current Population Survey are combined to evaluate the effects of PWL repeals on compensation. When comparing the experiences of different states, PWLs enhance both wages and benefits, with the largest percentage increase going toward employer pension contributions. PWLs appear to create an incentive for both employers to pay and workers to accept a larger percentage of their total compensation in the form of benefits. [source]