bluuebunny/crossref_metadata_2025 huggingface dataset:
Backstepping control design for motion coordination of self‐propelled vehicles in a flowfield
Authors: Mellish Rochelle , Napora Seth , Paley Derek A.
Published: February 2011

Motion coordination of autonomous vehicles has applications from target surveillance to climate monitoring. Previous research has yielded stabilizing control laws for a self‐propelled vehicle model with first‐order rotational dynamics, but this model does not adequately describe the rotational dynamics of vehicles in the atmosphere or ocean. This paper describes the design of backstepping algorithms for the decentralized control of self‐propelled vehicles with second‐order rotational dynamics. We design backstepping controls for parallel and circular formations in the absence of a flowfield and in the presence of a steady, uniform flowfield. These controls extend prior results to a more realistic vehicle model. Aside from the addition of new sensing and communication requirements, the second‐order control laws are demonstrated to have comparable performance to the first‐order controllers. Copyright © 2011 John Wiley & Sons, Ltd.
Cellular analysis by open‐source software for affordable cytometry
Authors: Mittag Anja , Pinto Fernanda E. , Endringer Denise C. , Tarnok Attila , Lenz Dominik
Published: February 2011

Image cytometry is an important technique in affordable healthcare and cellular research. Some efforts toward establishing a personal, low‐cost cytometer have been described in the literature. However, a self‐assembled fluorescence microscope requires software for cytometric analysis. There are some open‐source image‐based software analysis applications available. However, for a quantitative analysis of images, software that can generate data comparable to those of previously evaluated cytometric analyses programs is required. Hence, the aim of this study is to compare results of a commercially available image cytometry program to data obtained using the open‐source software CellProfiler (CP). Leukocytes and fluorescent bead images obtained using a Laser Scanning Cytometer were analyzed by CP and the results compared with those of conventional cytometric analyses' programs. Algorithms were developed enabling the analysis of leukocytes and beads by CP. CP provided similar results to those obtained by the cytometer software. Hallmark parameters, including cell count and fluorescence intensity, revealed a high correlation in the analysis of both programs. Therefore, CP is appropriate for cellular analysis on a self‐assembled microscope, thereby enabling affordable cytometry. SCANNING 33: 33–40, 2011. © 2011 Wiley Periodicals, Inc.
Chronic Work Stress and Depressive Symptoms: Assessing the Mediating Role of Teacher Burnout
Authors: Steinhardt Mary A. , Smith Jaggars Shanna E. , Faulk Kathryn E. , Gloria Christian T.
Published: February 2011

A conceptual model of the relationship between stress, the mediating role of burnout, and depressive symptoms was examined. Results indicated that teachers (n = 267) experiencing greater stress were more burned out. The subscale emotional exhaustion was moderately related to depressive symptoms, whereas depersonalization and reduced personal accomplishment had small positive relationships. After controlling for burnout and demographics, the relationship between stress and depressive symptoms was small but significant. Emotional exhaustion mediated the association between stress and depressive symptoms. The total effect of stress on depressive symptoms, taking together the direct and indirect effects via burnout, accounted for 43% of the total variance. Copyright © 2011 John Wiley & Sons, Ltd.
An Important Role for CDK2 in G1 to S Checkpoint Activation and DNA Damage Response in Human Embryonic Stem Cells
Authors: Neganova Irina , Vilella Felipe , Atkinson Stuart P. , Lloret Maria , Passos João F. , von Zglinicki Thomas , O'Connor José-Enrique , Burks Deborah , Jones Richard , Armstrong Lyle , Lako Majlinda
Published: February 2011

A precise understanding of mechanisms used by human embryonic stem cells (hESCs) to maintain genomic integrity is very important for their potential clinical applications. The G1 checkpoint serves to protect genomic integrity and prevents cells with damaged DNA from entering S-phase. Previously, we have shown that downregulation of cyclin-dependent kinase 2 (CDK2) in hESC causes G1 arrest, loss of pluripotency, upregulation of cell cycle inhibitors p21 and p27 and differentiation toward extraembryonic lineages. In this study, we investigate in detail the role of CDK2 in cellular processes, which are crucial to the maintenance of genomic stability in hESC such as G1 checkpoint activation, DNA repair, and apoptosis. Our results suggest that downregulation of CDK2 triggers the G1 checkpoint through the activation of the ATM-CHK2-p53-p21 pathway. Downregulation of CDK2 is able to induce sustained DNA damage and to elicit the DNA damage response (DDR) as evidenced by the formation of distinct γ-H2.AX and RAD52-BRCA1 foci in hESC nuclei. CDK2 downregulation causes high apoptosis at the early time points; however, this is gradually decreased overtime as the DDR is initiated. Our mass spectrometry analysis suggest that CDK2 does interact with a large number of proteins that are involved in key cellular processes such as DNA replication, cell cycle progression, DNA repair, chromatin modeling, thus, suggesting a crucial role for CDK2 in orchestrating a fine balance between cellular proliferation, cell death, and DNA repair in hESC.
Evo Devo and cognitive science
Authors: Ploeger Annemie , Galis Frietson
Published: February 2011

Evo Devo (evolutionary developmental) biology forges a synthesis of evolutionary and developmental processes. Evo Devo is the result of collaborative work of evolutionary and developmental biologists after the discovery of regulatory genes that human beings share with many other animals, including fruit flies, frogs, and rats. Compared to traditional evolutionary biologists, Evo Devo biologists focus on processes underlying the generation of evolutionary novelties, rather than on how natural selection changes gene frequencies in populations and how organisms are adapted to their environment. Evo Devo biologists try to answer questions such as: How do novel structures arise? Which mechanisms facilitate or constrain evolutionary change? In this article we argue that insights from Evo Devo research can contribute to the understanding of the evolution and development of cognition, and of the origin of neurocognitive disorders. We discuss three major Evo Devo topics: modularity, evolvability, and developmental constraints. We argue that each of these topics are relevant for research in cognitive science, and we argue that interdisciplinary research is necessary in order to unravel the evolutionary and developmental mechanisms of cognitive traits and disorders.WIREs Cogni Sci2011 2 429–440 DOI: 10.1002/wcs.137

This article is categorized under:

Cognitive Biology > Evolutionary Roots of Cognition
Time series modelling of power output for large‐scale wind fleets
Authors: Sturt Alexander , Strbac Goran
Published: February 2011

Simulations of power systems with high wind penetration need to represent the stochastic output of the wind farms. Many studies use historic wind data directly in the simulation. However, even if historic data are used to drive the realized wind output in scheduling simulations, a model of the wind's statistical properties may be needed to inform the commitment decisions for the dispatchable units. There are very few published studies that fit models to the power output of nation‐sized wind fleets rather than the output at a single location. We fitted a time series model to hourly, time‐averaged, aggregated wind power data from New Zealand, Denmark and Germany, based on univariate, second‐order autoregressive drivers. Our model is designed to reproduce the asymptotic distribution of power output, the diurnal variation and the volatility of power output over timescales up to several hours. For the cases examined here, it was also found to provide a generally good representation of the overall distribution of power output changes and the variation of volatility with power output level, as well as an acceptable representation of the distribution of calm periods. Copyright © 2011 John Wiley & Sons, Ltd.
An optimized autoregressive forecast error generator for wind and load uncertainty study
Authors: de Mello Phillip E. , Lu Ning , Makarov Yuri
Published: February 2011

This paper presents a first‐order autoregressive algorithm used to generate real‐time (RT), hour‐ahead (HA) and day‐ahead (DA) wind and load forecast errors in time series. The modeled error time series preserve the characteristics of the historical forecast data sets. Four statistical characteristics are considered: the means, the standard deviations, the autocorrelations and the cross‐correlations. A stochastic optimization routine was used to find an optimal set of parameters that minimize the differences of the four characteristics between the generated error series and the targeted ones. The obtained parameters were then in due order of succession used to produce the RT, HA and DA forecasts. This method, although implemented as a first‐order regressive random forecast error generator, can be extended to higher orders. Simulation results have shown that the methodology produces random forecast error series that have statistics similar to those derived from real data sets. The wind and load forecast error generator can be used in wind integration studies to produce wind and load forecast in time series for stochastic planning processes. Our future studies will focus on reflecting the diurnal and seasonal differences of the wind and load statistics and on implementing them in the random forecast generator. Copyright © 2011 John Wiley & Sons, Ltd.
Fundamentals of association rules in data mining and knowledge discovery
Authors: Zhang Shichao , Wu Xindong
Published: February 2011

Association rule mining is one of the fundamental research topics in data mining and knowledge discovery that identifies interesting relationships between itemsets in datasets and predicts the associative and correlative behaviors for new data. Rooted in market basket analysis, there are a great number of techniques developed for association rule mining. They include frequent pattern discovery, interestingness, complex associations, and multiple data source mining. This paper introduces the up‐to‐date prevailing association rule mining methods and advocates the mining of complete association rules, including both positive and negative association rules. © 2011 John Wiley & Sons, Inc. WIREs Data Mining Knowl Discov 2011 1 97‐116 DOI: 10.1002/widm.10

This article is categorized under:

Algorithmic Development > Association Rules
A study of methodological issues in design and development of rule‐based systems: proposal of a new approach
Authors: Ligęza Antoni , Nalepa Grzegorz J.
Published: February 2011

Rule‐based systems (RBSs) constitute a powerful technology for declarative encoding and automated processing of large bodies of knowledge. A typical RBS consists of a knowledge base containing facts and production rules, and an inference engine managing the reasoning process. Despite their simple conceptual scheme, design and development of a RBS often turn out to be unexpectedly complex task. This paper presents an overview of issues concerning design and development of such systems. Differences between RBSs and classical software are exemplified, and design and implementation issues are analyzed. A novel, consistent, three‐phase methodology incorporating conceptual, logical, and physical design is outlined. Moreover, tools supporting the complete design and development process are presented. © 2011 John Wiley & Sons, Inc. WIREs Data Mining Knowl Discov 2011 1 117‐137 DOI: 10.1002/widm.11

This article is categorized under:

Application Areas > Business and Industry

Fundamental Concepts of Data and Knowledge > Knowledge Representation

Technologies > Visualization
Ensembles of case‐based reasoning classifiers in high‐dimensional biological domains
Authors: Arshadi Niloofar , Jurisica Igor
Published: February 2011

In order to extend the capabilities of case‐based reasoning (CBR), we implemented an ensemble for case‐based reasoning (E4CBR) approach where an ensemble of CBR classifiers is combined with clustering and feature selection. We first select a subset of features of all the cases, and then cluster the cases into disjoint groups, where each group of cases forms the case‐base of one of the member classifiers. Finally, in each case‐base, a subset of features is ‘locally’ selected individually. To predict the label of an unseen case, each classifier in the ensemble provides a prediction, and the aggregation component of E4CBR combines the predictions by weighing each classifier using a CBR approach—a classifier with more cases similar to the test case receives a higher weight.We evaluated E4CBR on four publicly available biological data sets, and also compared the classification error of E4CBR with a single CBR classifier. In our experiments, we use TA3—a computational framework for CBR systems. Our results show that E4CBR reduces the classification error of our CBR classifier. On the basis of empirical results, our aggregation method outperforms the existing CBR aggregation methods. © 2011 John Wiley & Sons, Inc. WIREs Data Mining Knowl Discov 2011 1 164‐171 DOI: 10.1002/widm.22

This article is categorized under:

Algorithmic Development > Ensemble Methods
Tech mining: Text mining and visualization tools, as applied to nanoenhanced solar cells
Authors: Porter Alan L. , Guo Ying , Chiavatta Denise
Published: February 2011

‘Tech mining’ is a multistep process for the analysis of science, technology, & innovation (‘ST&I’) information resources. It uses text mining, visualization, and communication tools to provide the empirical knowledge necessary to address management of technology questions. Tech mining can help assess mature or emerging fields of science and technology, such as nanotechnology. Here, we depict select analyses and visualizations of relevant ST&I data on the topics of nanoenhanced, thin‐film solar cells and dye‐sensitized solar cells. These analyses help identify complementary and competitive research activity, evaluate research productivity, assess research interdisciplinarity, understand nanotechnology developmental trajectories, and identify and forecast promising nanoapplications. © 2011 John Wiley & Sons, Inc.WIREs Data Mining Knowl Discov2011 1 172‐181 DOI: 10.1002/widm.7

This article is categorized under:

Algorithmic Development > Text Mining

Application Areas > Education and Learning

Application Areas > Science and Technology

Technologies > Visualization
Mathematical models in biology: from molecules to life
Authors: Kaznessis Yiannis N.
Published: February 2011

A vexing question in the biological sciences is the following: can biological phenotypes be explained with mathematical models of molecules that interact according to physical laws? At the crux of the matter lies the doubt that humans can develop physically faithful mathematical representations of living organisms.

We discuss advantages that synthetic biological systems confer that may help us describe life's distinctiveness with tractable mathematics that are grounded on universal laws of thermodynamics and molecular biology. WIREs Syst Biol Med 2011 3 314–322 DOI: 10.1002/wsbm.142

This article is categorized under:

Analytical and Computational Methods > Analytical Methods

Models of Systems Properties and Processes > Organismal Models
Crystal and Molecular Structure of the trans‐Hyponitrite Compound Ph3Sn(μ‐ONNO)SnPh3
Authors: Mayer Tobias , Beck Wolfgang , Böttcher Hans‐Christian
Published: February 2011

The trans‐hyponitrite compound Ph3Sn(μ‐ONNO)SnPh3 (1) was revisited by NMR spectroscopy and the crystal and molecular structure was elucidated by X‐ray diffraction. Compound 1 crystallizes from benzene in the triclinic space group P$\bar{1}$ with a = 10.9674(2), b = 18.2786(2), c = 18.4592(2) Å; α = 115.979(1), β = 102.851(1), γ = 99.032(1)°; V = 3103.60(9) Å3; Z = 4, ρ = 1.627 g·cm–3, T = 173(2) K.
Results of the third reproductive assessment survey of north American Asian (Elephas maximus) and African (Loxodonta africana) female elephants
Authors: Dow T.L. , Holásková I. , Brown J.L.
Published: February 2011

A written survey assessed reproductive status of female Asian and African elephants in AZA/SSP facilities in 2008, and data were compared to surveys conducted in 2002 and 2005. Results showed that ovarian acyclicity rates across the surveys remained unchanged for Asian (13.3, 10.9 and 11.1%) and African (22.1, 31.2 and 30.5%) elephants, respectively (P>0.05), but were higher overall for African compared to Asian elephants (P<0.05). In 2008, the percentages of Asian and African elephants with irregular cycles (14.3 and 15.8%) and irregular + no cycles (25.4 and 46.4%) was similar to 2005 (7.6 and 11.8%; 18.5 and 43.0%), but were increased compared to 2002 (2.6 and 5.2%; 16.0 and 27.3%), respectively (P<0.05). For both species, ovarian acyclicity increased with age (P<0.05). Reproductive tract pathologies did not account for the majority of acyclicity, although rates were higher in noncycling females (P<0.05). Bull presence was associated with increased cyclicity rates (P<0.05) for Asian (92.5 vs. 58.3%) and African (64.9 vs. 57.8%) elephants compared to females at facilities with no male, respectively. Cyclicity rates were higher for Asian (86.8 vs. 65.2%) and African (67.9 vs. 56.7%) elephants managed in free compared to protected contact programs (P<0.05), respectively. Geographical facility location had no effect on cyclicity (P>0.05). In summary, incidence of ovarian cycle problems continues to predominantly affect African elephants. Although percentages of acyclicity did not increase between 2005 and 2008, 42.2% Asian and 30.2% African females were no longer being hormonally monitored; thus, reproductive cycle abnormalities could be worse than current data suggest. Zoo Biol 30:699–711, 2011. © 2011 Wiley Periodicals, Inc.
Genome-wide identification and annotation of HIF-1α binding sites in two cell lines using massively parallel sequencing
Authors: Tanimoto Kousuke , Tsuchihara Katsuya , Kanai Akinori , Arauchi Takako , Esumi Hiroyasu , Suzuki Yutaka , Sugano Sumio
Published: February 2011

We identified 531 and 616 putative HIF-1α target sites by ChIP-Seq in the cancerous cell line DLD-1 and the non-cancerous cell line TIG-3, respectively. We also examined the positions and expression levels of transcriptional start sites (TSSs) in these cell lines using our TSS-Seq method. We observed that 121 and 48 genes in DLD-1 and TIG-3 cells, respectively, had HIF-1α binding sites in proximal regions of the previously reported TSSs that were up-regulated at the transcriptional level. In addition, 193 and 123 of the HIF-1α target sites, respectively, were located in proximal regions of previously uncharacterized TSSs, namely, TSSs of putative alternative promoters of protein-coding genes or promoters of putative non-protein-coding transcripts. The hypoxic response of DLD-1 cells was more significant than that of TIG-3 cells with respect to both the number of target sites and the degree of induced changes in transcript expression. The Nucleosome-Seq and ChIP-Seq analyses of histone modifications revealed that the chromatin formed an open structure in regions surrounding the HIF-1α binding sites, but this event occurred prior to the actual binding of HIF-1α. Different cellular histories may be encoded by chromatin structures and determine the activation of specific genes in response to hypoxic shock.
Targeted treatments for fragile X syndrome
Authors: Berry-Kravis Elizabeth , Knox Andrew , Hervey Crystal
Published: February 2011

Fragile X syndrome (FXS) is the most common identifiable genetic cause of intellectual disability and autistic spectrum disorders (ASD), with up to 50% of males and some females with FXS meeting criteria for ASD. Autistic features are present in a very high percent of individuals with FXS, even those who do not meet full criteria for ASD. Recent major advances have been made in the understanding of the neurobiology and functions of FMRP, the FMR1 (fragile X mental retardation 1) gene product, which is absent or reduced in FXS, largely based on work in the fmr1 knockout mouse model. FXS has emerged as a disorder of synaptic plasticity associated with abnormalities of long-term depression and long-term potentiation and immature dendritic spine architecture, related to the dysregulation of dendritic translation typically activated by group I mGluR and other receptors. This work has led to efforts to develop treatments for FXS with neuroactive molecules targeted to the dysregulated translational pathway. These agents have been shown to rescue molecular, spine, and behavioral phenotypes in the FXS mouse model at multiple stages of development. Clinical trials are underway to translate findings in animal models of FXS to humans, raising complex issues about trial design and outcome measures to assess cognitive change that might be associated with treatment. Genes known to be causes of ASD interact with the translational pathway defective in FXS, and it has been hypothesized that there will be substantial overlap in molecular pathways and mechanisms of synaptic dysfunction between FXS and ASD. Therefore, targeted treatments developed for FXS may also target subgroups of ASD, and clinical trials in FXS may serve as a model for the development of clinical trial strategies for ASD and other cognitive disorders.
Release of Omega‐3 Fatty Acids by the Hydrolysis of Fish Oil Catalyzed by Lipases Immobilized on Hydrophobic Supports
Authors: Fernández‐Lorente Gloria , Betancor Lorena , Carrascosa Alfonso V. , Guisán Jose M.
Published: February 2011

The release of omega‐3 fatty acids by the mild enzymatic hydrolysis of sardine oil was studied. The derivatives of different lipases physically adsorbed on hydrophobic porous supports Hydrophobic Lipase Derivatives (HLD) were tested. These immobilized lipases can only hydrolyze oil molecules partitioned into the aqueous phase of a biphasic reaction system. HLD biocatalysts were compared to other enzyme derivatives that were obtained by very mild covalent immobilization on CNBr‐activated Sepharose Cyanogen bromide Lipase Derivatives (CNLD) that behave almost identically to soluble enzymes (CNLD). In general, HLD biocatalysts were found to be more active and more selective for the release of eicosapentaenoic acid (EPA) than CNLD. The most interesting biocatalyst was the HLD derivative of Yarrowia lipolytica lipase, which was found to be sevenfold more active and tenfold more selective than CNLD. On the other hand, the most active (but non‐selective) derivative was the HLD of Pseudomonas fluorescens lipase (PFL). The activity of this derivative was 0.6 International Units under non‐optimal reaction conditions. High‐loaded PFL derivatives could be very interesting for the release of mixtures of EPA and docosahexaenoic acid. Hydrophobic supports promote the interfacial activation of lipases, similar to the interaction promoted by oil drops on soluble enzymes. The most effective overactivation obtained in this work ranged from 6‐ to 20‐fold. The hydrolytic process was carried out under very mild conditions (pH 7.0 and 25 °C), and all lipase derivatives remained fully active for at least 15 days under these conditions.
Equity in the Context of a Crisis: Funding for Higher Education Post-Katrina
Authors: Johnson Barbara J.
Published: February 2011

This manuscript examines the context for the inequities relative to funding for postsecondary institutions, particularly historically black institutions, in the aftermath of Hurricane Katrina. A discussion of the formula used to distribute federal monies presents data on the allocation of funds relative to losses of the institutions. Specifically, differences across institutional type (characteristics and size of student population, damage received, location, etc.) provide an in-depth understanding of the inequities for higher education institutions in New Orleans, particularly those with extensive physical damage. The conclusion discusses the disparate impact of the distribution of federal funds to historically black colleges and universities.
Altérations environnementales du développement du testicule foetal: zoom sur les phtalates
Authors: Habert R. , Muczynski V. , Lehraiki A. , Moison D. , Lambrot R. , Levacher C. , Lécureuil C. , Frydman R. , Rouiller-Fabre V.
Published: February 2011

L’augmentation de plusieurs anomalies de la fonction de reproduction masculine suscite de grandes inquiétudes. Au cours des quatre dernières décennies, le nombre de spermatozoïdes chez l’homme a nettement diminué, et l’incidence du cancer testiculaire a doublé. De plus, les cas de cryptorchidie et d’hypospadias sont également en augmentation. L’hypothèse la plus couramment admise est que tous ces effets néfastes sur la fonction reproductive masculine résulteraient d’anomalies survenant lors du développement du testicule pendant la vie foetale et néonatale. En outre, de nombreuses données épidémiologiques, cliniques et expérimentales suggèrent que ces troubles pourraient être dus aux effets de xénobiotiques appelés perturbateurs endocriniens qui sont de plus en plus concentrés et présents dans notre environnement. Parmi les perturbateurs endocriniens, nous avons choisi de focaliser cette revue sur les phtalates pour diverses raisons: 1) ils sont très répandus dans l’environnement; 2) leurs concentrations dans de nombreux fluides biologiques humains ont été mesurées y compris pendant la grossesse; 3) les données expérimentales utilisant le modèle rat et suggérant une reprotoxicité sont nombreuses et pertinentes; 4) les effets délétères des phtalates sur le développement et sur les fonctions du testicule foetal de rat ont largement été étudiés; 5) quelques données épidémiologiques humaines suggèrent un effet reprotoxique des phtalates aux concentrations retrouvées dans l’environnement, au moins durant la vie néonatale. Cependant, les effets directs des phtalates sur le testicule foetal humain n’avaient jamais été étudiés. Comme nous l’avions fait chez le rat dans les années 1990, nous avons récemment développé et validé un système de culture organotypique de testicule foetal humain qui permet de maintenir in vitro le développement des différents types cellulaires. Dans ce système, l’ajout de 10−4M de MEHP (mono-2-éthylhexyl phtalate), le phtalate le plus répandu, n’a aucun effet sur la production de testostérone basale ou stimulée par l’hormone lutéinisante (LH), mais il réduit le nombre de cellules germinales en augmentant leur apoptose et sans modifier leur prolifération. Nos données constituent la première donnée expérimentale montrant que les phtalates altèrent le développement du testicule foetal humain. En outre, en utilisant le même système de culture organotypique, il est intéressant de comparer la réponse au MEHP chez l’Homme et chez les rongeurs pour analyser la pertinence des tests toxicologiques basés sur le modèle rongeur.
Overuse Injuries in High School Runners: Lifetime Prevalence and Prevention Strategies
Authors: Tenforde Adam S. , Sayres Lauren C. , McCurdy Mary L. , Collado Hervé , Sainani Kristin L. , Fredericson Michael
Published: February 2011

Objective

To evaluate lifetime prevalence and risk factors for overuse injuries in high school athletes currently participating in long‐distance running and provide recommendations for injury prevention strategies.

Design

Retrospective study design.

Setting

Twenty‐eight high schools in the San Francisco Bay Area.

Participants

A total of 442 female and 306 male athletes, ages 13‐18 years, who are on cross‐country and track and field teams.

Methods

Online survey with questions that detailed previous injuries sustained and risk factors for injury.

Main Outcome Measurements

Previous overuse injuries and association of risk factors to injury (including training variables, dietary patterns, and, in girls, menstrual irregularities).

Results

Previous injuries were reported by 68% of female subjects and 59% of male subjects. More injury types were seen in girls (1.2 ± 1.1 versus 1.0 ± 1.0, P < .01). Both genders had similar participation in running (2.5 ± 2.2 versus 2.3 ± 2.1 years), and previous injury prevalence followed a similar pattern: tibial stress injury (girls, 41%; boys, 34%), ankle sprain (girls, 32%; boys, 28%), patellofemoral pain (girls, 21%; boys, 16%), Achilles tendonitis (girls, 9%; boys, 6%), iliotibial band syndrome (girls, 7%; boys, 5%), and plantar fasciitis (girls, 5%; boys, 3%). Higher weekly mileage was associated with previous injuries in boys, (17.1 ± 11.9 versus 14.1 ± 11.5, P < .05) but not in girls (14.4 ± 10.2 versus 12.6 ± 11.8, not significant). A strong association between higher mileage and faster performances was seen in both groups. No association between previous injury and current dietary patterns (including disordered eating and calcium intake) or menstrual irregularities was seen.

Conclusions

The majority of athletes currently participating in high school cross‐country and track and field have a history of sustaining an overuse injury, with girls having a higher prevalence of injury. A modest mileage reduction may represent a modifiable risk factor for injury reduction. Future research is needed to evaluate the effects of incorporating a comprehensive strength training program on the prospective development of overuse injury and performance in this population.
Treatments for Osteoporosis in People With a Disability
Authors: Smith Éimear M.
Published: February 2011

The morbidity from osteoporotic fractures for people with a disability is considerable because of the increased risk of medical complications, loss of independence and mobility, and prolonged hospitalization. The frequency with which low bone mineral density occurs in people with a disability is now well recognized, and professionals have a greater awareness of the need to investigate bone mineral density levels with a view to preventing fragility fractures. After patients with osteoporosis are identified, the challenge is to treat them appropriately. This article reviews the physical and pharmacologic measures that have been researched in the prevention and treatment of low bone mineral density in people with a disability.
Thigh and Knee Circumference, Knee‐Extension Strength, and Functional Performance After Fast‐Track Total Hip Arthroplasty
Authors: Holm Bente , Kristensen Morten Tange , Husted Henrik , Kehlet Henrik , Bandholm Thomas
Published: February 2011

Objective

To (1) quantify changes in knee‐extension strength and functional‐performance at discharge after fast‐track total hip arthroplasty (THA) and (2) investigate whether these changes correlate to changes in thigh and knee circumference (ie, swelling) or pain.

Design

A prospective, descriptive, hypothesis‐generating study.

Setting

A special unit for fast‐track hip and knee arthroplasty operations at a university hospital.

Participants

Twenty‐four patients (20 women and 4 men; ages 69 ± 6.1 years) scheduled for primary unilateral THA.

Methods

All patients were evaluated before surgery and on the day of hospital discharge.

Main Outcome Measures

Knee‐extension strength, thigh and knee joint circumference, hip pain, and functional performance (Timed Up & Go, 30‐Second Chair Stand, and 10‐Meter Walk tests).

Results

All investigated variables changed significantly from before to after surgery, except for hip pain. The average loss in knee‐extension strength after surgery (32%, P = .01) did not correlate with increased thigh circumference (6%, P < .01) or knee circumference (3%, P < .01) or with reductions in functional performance: Timed Up & Go test (114%, P = .01), 30‐Second Chair Stand test (36%, P = .01), and 10‐Meter Walk test (50%, P < .01). Only the increase in knee circumference correlated significantly with reduced performance in the 10‐Meter Walk test time (R = −0.59, P < .01), explaining 34% of the variance in the 10‐Meter Walk test. No correlations between changes in hip pain and functional performance or knee‐extension strength were found. Mean postoperative hospital stay was 2.1 days.

Conclusions

Knee‐extension strength is considerably reduced at discharge after THA, but the early strength reduction does not correlate with changes in thigh or knee circumferences. Because functional performance is also considerably reduced at discharge (unrelated to reduced knee‐extension strength), other mechanisms such as fear, avoidance of movement, or decreased hip‐muscle strength also may be involved.
Comparison of Quadriceps Angle Measurements Using Short‐Arm and Long‐Arm Goniometers: Correlation With MRI
Authors: Draper Christine E. , Chew Kelvin T.L. , Wang Roberta , Jennings Fabio , Gold Garry E. , Fredericson Michael
Published: February 2011

Objective

To compare the reliability of quadriceps‐angle (Q‐angle) measurements performed using a short‐arm goniometer and a long‐arm goniometer and to assess the accuracy of goniometer‐based Q‐angle measurements compared with anatomic Q angles derived from magnetic resonance imaging (MRI).

Design

An intra‐ and interobserver reliability study.

Setting

University hospital.

Participants

Eighteen healthy subjects with no history of knee pain, trauma, or prior surgery were examined.

Methods

Two physicians, blinded to subject identity, measured Q angles on both knees of all subjects using 2 goniometers: (1) a short‐arm goniometer and (2) a long‐arm goniometer. Q angles were derived from axial MRIs of the subjects' hip and knees.

Main Outcome Measurements

The intra‐ and interobserver reliabilities of each goniometer were assessed using the intraclass correlation coefficient (ICC). The comparison between clinical and MRI‐based Q angles was assessed by using the ICC and a paired t‐test.

Results

Intra‐ and interobserver reliabilities of the long‐arm goniometer (intraobserver ICC, 0.92; interobserver ICC, 0.88) were better than those of the short‐arm goniometer (intraobserver ICC, 0.78; interobserver ICC, 0.56). Although both goniometers measured Q angles that were moderately correlated to the MRI‐based measurements (ICC, 0.40), the clinical Q angles were underestimated compared with the MRI‐based anatomic Q angles (P < .05).

Conclusion

The results of this study suggest that, although reproducible Q‐angle measurements can be performed using standardized patient positioning and a long‐arm goniometer, methods to improve the accuracy of clinical Q‐angle measurements are needed.
The Deep Neck Flexor Endurance Test: Normative Data Scores in Healthy Adults
Authors: Domenech Manuel A. , Sizer Phil S. , Dedrick Gregory S. , McGalliard Michael K. , Brismee Jean‐Michel
Published: February 2011

Objective

To investigate (1) the average hold time for the deep neck flexors (DNF) endurance test in subjects without neck pain or pathology, and (2) whether different groups of subjects categorized by age, gender, and lifestyle display different hold times.

Design

Normative research.

Patients

A convenience sample of 126 adults participated.

Methods

Intertester reliability of 4 therapists was evaluated by using intraclass correlation coefficients. The DNF endurance test hold time was conducted on each subject twice. The 2 hold‐time scores were averaged and recorded.

Results

Inter‐rater reliability coefficient of reproducibility for DNF muscle endurance measured by 4 physical therapists was ICC (2,k) 0.66 (confidence interval, 0.34‐0.86). The mean (SD) DNF endurance hold times for men was 38.9 ± 20.1 seconds, whereas women was 29.4 ± 13.7 seconds. Results of the 2 × 2 analysis of variance indicated that gender significantly influenced DNF endurance (F = 8.643; P = .004), whereas, the activity level did not (F = 3.143; P = .079). Correlations were not significant between age and DNF endurance (r = 0.11; P = .2) and between activity level and DNF endurance (r = −0.156; P = .08).

Conclusions

Asymptomatic men displayed greater DNF endurance than women. The variability between subjects' DNF endurance capabilities was high. Age between 20 and 80 years and activity level did not affect DNF endurance. This is the first normative data set available for the DNF endurance test, which lays the foundation for further research in subjects with a history of cervicalgia and assists clinicians to objectify a milestone for DNF endurance deficits in patients.
Intersection K-theory for isolated conical singularities
Authors: Legrand André , Poutriquet David
Published: February 2011

Starting from the Karoubi multiplicative K-theory, we construct a Chern-Weil theory adapted to isolated conical singularities. The Chern character takes its values in the intersection cohomology of Goresky-MacPherson. We also propose an integer intersection K-theory for such singularities.
A discussion support model for a regional dairy–pasture system with an example from Réunion island
Authors: NIDUMOLU U. B. , LUBBERS M. , ALARY V. , LECOMTE P. , VAN KEULEN H.
Published: February 2011

Réunion Island, situated in the Indian Ocean, presents a unique case study for modelling regional bio-economic parameters of the dairy industry. It is a good example of a closed system for several parameters of the model such as movement of animals, labour, consumption and available land. The existence of several agro-ecological zones from tropical to temperate, and various different types of terrain and vegetation presents another unique opportunity to study the impact of these features on the dairy industry. The present study models the dairy sector at a regional (island) level to study the impact of new or adapted agricultural policies in relation to changes in subsidy levels, price fluctuations and environmental policies (mainly nitrogen management). The model can be used to generate a number of scenarios to explore the effects of various policy measures, such as fixing the stocking rate according to EU norms, increasing or decreasing the milk subsidy, intensification (such as an increase in milk production to the allotted quota of 40 million litres/yr) and varying labour/price constraints (such as a reduction in labour hours or an increase or decrease in the milk price). The model is being utilized by the local dairy cooperative as a discussion support tool to study the implications at the regional scale of expanding the sector and assessing its economic, environmental and social impact.
The Influence of Affect on Beliefs, Preferences, and Financial Decisions
Authors: Kuhnen Camelia M. , Knutson Brian
Published: February 2011

Neuroeconomics research shows that brain areas that generate emotional states also process information about risk, rewards, and punishments, suggesting that emotions influence financial decisions in a predictable and parsimonious way. We find that positive emotional states such as excitement induce people to take risks and to be confident in their ability to evaluate investment options, while negative emotions such as anxiety have the opposite effects. Beliefs are updated so as to maintain a positive emotional state by ignoring information that contradicts individuals’ prior choices. Marketplace features or outcomes of past choices may change emotions and thus influence future financial decisions.
Nonlinear stability and patterns in granular plane Couette flow: Hopf and pitchfork bifurcations, and evidence for resonance
Authors: SHUKLA PRIYANKA , ALAM MEHEBOOB
Published: February 2011

The first evidence of a variety of nonlinear equilibrium states of travelling and stationary waves is provided in a two-dimensional granular plane Couette flow via nonlinear stability analysis. The relevant order-parameter equation, the Landau equation, has been derived for the most unstable two-dimensional perturbation of finite size. Along with the linear eigenvalue problem, the mean-flow distortion, the second harmonic, the distortion to the fundamental mode and the first Landau coefficient are calculated using a spectral-based numerical method. Two types of bifurcations, Hopf and pitchfork, that result from travelling and stationary instabilities, respectively, are analysed using the first Landau coefficient. The present bifurcation theory shows that the flow is subcritically unstable to stationary finite-amplitude perturbations of long wavelengths (kx ~ 0, where kx is the streamwise wavenumber) in the dilute limit that evolve from subcritical shear-banding modes (kx = 0), but at large enough Couette gaps there are stationary instabilities with kx = O(1) that lead to supercritical pitchfork bifurcations. At moderate-to-large densities, in addition to supercritical shear-banding modes, there are long-wave travelling instabilities that lead to Hopf bifurcations. It is shown that both supercritical and subcritical nonlinear states exist at moderate-to-large densities that originate from the dominant stationary and travelling instabilities for which kx = O(1). Nonlinear patterns of density, velocity and granular temperature for all types of instabilities are contrasted with their linear eigenfunctions. While the supercritical solutions appear to be modulated forms of the fundamental mode, the structural features of unstable subcritical solutions are found to be significantly different from their linear counterparts. It is shown that the granular plane Couette flow is prone to nonlinear resonances in both stable and unstable regimes, the signature of which is implicated as a discontinuity in the first Landau coefficient. Our analysis identified two types of modal resonances that appear at the quadratic order in perturbation amplitude: (i) a ‘mean-flow resonance’ which occurs due to the interaction between a streamwise-independent shear-banding mode (kx = 0) and a linear/fundamental mode kx ≠ 0, and (ii) an exact ‘1 : 2 resonance’ that results from the interaction between two waves with their wavenumber ratio being 1 : 2.
Stabilizing effect of surrounding gas flow on a plane liquid sheet
Authors: TAMMISOLA OUTI , SASAKI ATSUSHI , LUNDELL FREDRIK , MATSUBARA MASAHARU , SÖDERBERG L. DANIEL
Published: February 2011

The stability of a plane liquid sheet is studied experimentally and theoretically, with an emphasis on the effect of the surrounding gas. Co-blowing with a gas velocity of the same order of magnitude as the liquid velocity is studied, in order to quantify its effect on the stability of the sheet. Experimental results are obtained for a water sheet in air at Reynolds numberRel= 3000 and Weber numberWe= 300, based on the half-thickness of the sheet at the inlet, water mean velocity at the inlet, the surface tension between water and air and water density and viscosity. The sheet is excited with different frequencies at the inlet and the growth of the waves in the streamwise direction is measured. The growth rate curves of the disturbances for all air flow velocities under study are found to be within 20% of the values obtained from a local spatial stability analysis, where water and air viscosities are taken into account, while previous results from literature assuming inviscid air overpredict the most unstable wavelength with a factor 3 and the growth rate with a factor 2. The effect of the air flow on the stability of the sheet is scrutinized numerically and it is concluded that the predicted disturbance growth scales with (i) the absolute velocity difference between water and air (inviscid effect) and (ii) the square root of the shear from air on the water surface (viscous effect).
LANGUAGE ASSESSMENT POLICY IN IRAN
Authors: Farhady Hossein , Hedayati Hora
Published: February 2011

Despite its geopolitical reputation, Iran has been quite underrepresented in studies of its sociopolitically dominated religious educational framework and its language teaching and assessment policy. In the aftermath of the Islamic Revolution in 1979, major restructuring was planned for foreign language teaching and assessment to accord with Islamic values. However, due to political obstacles, including the long-lasting war between Iran and Iraq, most of the plans could not be implemented until years after the revolution. Since high-stakes language tests including university entrance examinations are developed, administered, and scored by the government agencies, independent researchers do not have access to test data. A critical review of the language assessment policy in Iran requires research-based data, which is, in many cases, lacking or sporadic. This article is an attempt to provide some basic documented information about the educational system, foreign language teaching, and assessment in Iran.
PLOTINUS ARABUS RIDES AGAIN
Authors: Hansberger Rotraud
Published: February 2011

The extant texts of the Arabic Plotinus contain material fromEnneadsIV-VI without, however, covering the Plotinian treatises in their entirety, nor preserving their traditional order – a circumstance which raises questions about scope and structure of the original Arabic Plotinus source. This article aims to contribute to the discussion by presenting newly discovered fragments of an Arabic translation ofEnneadIV.6 (On sense-perception and memory), one of the ten treatises that are not represented in the Arabic Plotinus corpus as it is currently known. Section I of the article introduces the text within which the new fragments are found:MaqālaI ofKitāb al-Ḥiss wa-al-maḥsūs, the Arabic adaptation of Aristotle'sParva Naturalia. In Section II the Arabic fragments are presented in comparison with their Greek counterparts. Section III addresses the question whether these new fragments stem from the same original translation as the other fragments of the Arabic Plotinus. Section IV discusses the implications which the appearance of the new fragments may have for our views on the Arabic Plotinus as well as on the genesis ofKitāb al-Ḥiss wa-al-maḥsūs.
LE STATUT DE LA RAISON PRATIQUE CHEZ AVEMPACE
Authors: Abbès Makram
Published: February 2011

This paper seeks to draw attention to the existence of strong practical rationality in the work of Avempace, despite the primacy of theoretical reason, and of the search for an intelligible that is devoid of any link with the material and considered itself as the supreme end of human existence. The arguments used to defend the idea entail analysing the concept of “prudence” in Avempace, as well as that of “right thinking”, which is prominent in the determination of the way of life that philosophers must adopt in unjust cities. In addition, the elucidation of these aspects is a measure of the intellectual distance between Avempace and the mystics, both on the ethical-political and ontotheological levels.
IBN BĀJJA ON MEDICINE AND MEDICAL EXPERIENCE
Authors: Forcada Miquel
Published: February 2011

This article lists the medical works written by Ibn Bājja, overviews those that have come down to us and studies the super-commentary of Galen's commentary to Hippocrates'Aphorisms(Sharḥ fī al-Fuṣūl). This text shows a deep influence of al-Fārābī, namely in a conception of medical experience which stems from the latter's construal of experience (tajriba) as the inductive process described by Aristotle inPosterior Analyticswhich brings the premises of demonstration. On this basis, Ibn Bājja advocated for a less scholastic, more empiric medicine, and his claim was echoed by Ibn Rushd. There are some similarities between Ibn Bājja's text and Ibn Rushd'sK. al-Kulliyyāt fī al-ṭibbwhich suggest that the latter had readSharḥ fī al-Fuṣūl.This work gives moreover some evidence that human dissection could have been performed during Ibn Bājja's time.