bluuebunny/crossref_metadata_2025_split huggingface dataset:
A test of the mechanisms behind avian generalized individuals–area relationships
Authors: Pautasso Marco , Gaston Kevin J. 
Published: September 2006

ABSTRACTAim  Questions related to abundances of organisms are central to ecological research. A priori, a scale independent estimation of abundances would be expected. However, we find estimates of numbers of bird individuals from all over the world to increase less than proportionately with increasing plot size. At the whole assemblage level, the pattern holds across biogeographical regions and habitats. The slope of the interspecific and, for the majority of species, the intraspecific individuals–area relationship is also significantly shallower than 1. The question arises as to which mechanisms cause these patterns.Location  Global.Methods  At the assemblage, interspecific and intraspecific levels, we tested three mechanisms that could be responsible for these patterns by comparing the slope of the individuals–plot area relationship for subsets of a database compiled from the literature. Spatial autocorrelation was controlled for.Results  There was no evidence for an influence of plot area choice in order to sample a constant number of individuals. Evidence for higher survey efficiency was available only with increasing number of visits at the intraspecific level. Evidence for influences of habitat heterogeneity was present at the assemblage, interspecific and intraspecific levels. This mechanism can work only if small plots are delimited non‐randomly in homogeneous habitat.Main conclusions  Avian population size estimates without indication of the area over which they were obtained are of substantially less value than those coupled with that information. Ecologists planning to compare avian abundances between plots varying in some other factor of interest should minimize variations in their areas and/or account for them in data analyses. Population viability analyses, regional and global population size estimates, site prioritization and the scaling of ecosystem and species energy utilization need to address the plot area effect on assemblage and individual species abundances.
A resource‐based conceptual model of plant diversity that reassesses causality in the productivity–diversity relationship
Authors: Lavers Chris , Field Richard 
Published: September 2006

ABSTRACTBiogeographical studies frequently reveal positive correlations between species richness and estimates of environmental water and/or energy. A popular interpretation of this relationship relates the supply of water and energy to productivity, and then, in turn, to richness. Productivity–diversity theories are now legion, yet none has proved sufficiently intuitive to gain broad acceptance. Like productivity, heterogeneity is known to influence diversity at fine spatial scales, yet the possibility that richness might relate to water–energy dynamics at coarse spatial scales via a heterogeneity‐generating mechanism has received little attention. In this paper we outline such a conceptual model for plants that is internally consistent and testable. We believe it may help to explain the capacity of environments receiving different inputs of water and energy to support variable numbers of species at a range of spatial scales, the pervasive correlation between productivity and richness, some exceptions to the productivity–diversity relationship, the form of productivity–diversity curves and the link between richness and environmental ‘harshness’. The model may also provide an answer to one of the most venerable puzzles in the field of diversity studies: why high inputs of water and energy correspond to more species rather than simply more individuals.
Sensitivity of African biomes to changes in the precipitation regime
Authors: Hély Christelle , Bremond Laurent , Alleaume Samuel , Smith Benjamin , Sykes Martin T. , Guiot Joël 
Published: September 2006

ABSTRACTAim  Africa is identified by the Inter‐governmental Panel on Climate Change (IPCC) as the least studied continent in terms of ecosystem dynamics and climate variability. The aim of this study was (1) to adapt the Lund‐Postdam‐Jena‐GUESS (LPJ‐GUESS) ecological modelling framework to Africa by providing new parameter values for tropical plant functional types (PFT), and (2) to assess the sensitivity of some African biomes to changes in precipitation regime.Location  The study area was a representative transect (0–22° N and 7–18° E) through the transition from equatorial evergreen forests to savannas, steppes and desert northwards. The transect showed large latitudinal variation in precipitation (mean rainfall ranged from 50 to 2300 mm year−1).Methods  New PFT parameters used to calibrate LPJ‐GUESS were based on modern pollen PFTs and remote sensed leaf area index (LAI). The model was validated using independent modern pollen assemblages, LAI and through comparison with White's modern potential vegetation map. Several scenarios were developed by combining changes in total rainfall amount with variation in the length of the dry season in order to test the sensitivity of African biomes.Results  Simulated vegetation compared well to observed data at local and regional scales, in terms of ecosystem functioning (LAI), and composition (pollen and White's vegetation map). The assessment of the sensitivity of biomes to changes in precipitation showed that none of the ecosystems would shift towards a new type under the range of precipitation increases suggested by the IPCC (increases from 5 to 20%). However, deciduous and semi‐deciduous forests may be very sensitive to small reductions in both the amount and seasonality of precipitation.Main conclusions  This version of LPJ‐GUESS parameterized for Africa simulated correctly the vegetation present over a wide precipitation gradient. The biome sensitivity assessment showed that, compared with savannas and grasslands, closed canopy forests may be more sensitive to change in precipitation regime due to the synergetic effects of changed rainfall amounts and seasonality on vegetation functioning.
Epicardial fat: properties, function and relationship to obesity
Authors: Rabkin S. W. 
Published: September 2006

SummaryEpicardial fat is a relatively neglected component of the heart. The purpose of this review was to examine the anatomic and biochemical data on epicardial fat; to examine the relationship of epicardial fat to obesity and to explore the potential role of epicardial fat in the relationship of obesity to coronary atherothrombotic disease. Epicardial fat covers 80% of the heart’s surface and constitutes 20% of total heart weight. It is present along the distribution of the coronary arteries, over the right ventricle especially along the right border, anterior surface and at the apex. There is three‐ to fourfold more epicardial fat associated with the right than the left ventricle. Putative physiologic functions of epicardial fat are based on observational data and include: buffering coronary arteries against the torsion induced by the arterial pulse wave and cardiac contraction, facilitating coronary artery remodelling, regulating fatty acid homeostasis in the coronary microcirculation and providing fatty acids to cardiac muscle as a local energy source in times of high demand. A considerable amount of the data on epicardial fat originates from autopsy series that have the inherent problem that conditions leading to death may have altered body composition and adiposity. With this caveat, data indicate that epicardial fat mass increases age until age 20–40 years but thereafter the amount of epicardial fat is not dependent on age. The amount of epicardial fat correlates with heart weight but the presence of myocardial ischemia and hypertrophy does not alter the ratio of epicardial fat to cardiac muscle mass. A number of properties differentiate epicardial fat from other fat depots specifically its smaller adipocytes size; different fatty acid composition, high protein content; high rates of fatty acid incorporation, fatty acid synthesis, insulin‐induced lipogenesis or fatty acid breakdown; low rates of glucose utilization, low expression (mRNA) of lipoprotein lipase, stearoyl‐CoA desaturase and acetyl‐CoA carboxylase‐α, and slow regression during weight loss. There is a significant direct relationship between the amount of epicardial fat and general body adiposity. Clinical imaging studies have demonstrated a strong direct correlation between epicardial fat and abdominal visceral adiposity. Several lines of evidence support a role for epicardial fat in the pathogenesis of coronary artery disease, namely the close anatomic relationship between epicardial fat and coronary arteries; the positive correlation between the amount of epicardial fat and the presence of coronary atherosclerosis and the ability of adipose tissue to secrete hormones and cytokines that modulate coronary artery atherothrombosis. Thus, epicardial fat maybe an important factor responsible for cardiovascular disease in obesity.
Measurement of television viewing in children and adolescents: a systematic review
Authors: Bryant M. J. , Lucove J. C. , Evenson K. R. , Marshall S. 
Published: September 2006

SummaryThe relationship between television (TV) viewing and overweight in children is likely to be influenced by the quality of measures used. We systematically reviewed studies related to overweight in children that had included a measure of TV exposure. Literature searches were conducted in MedLINE, PsychInfo, SportDiscus and ISIWeb of Science. Methods of assessing TV viewing were evaluated, including the type of measure, the administration procedure and reported psychometric properties. The majority of studies assessed TV viewing using self‐report surveys and very few studies used direct observation. The validity or reliability of measures was often not examined. The majority of tools that were evaluated were compared with another self‐report measure or an objective measure of physical activity. TV viewing measures should be selected that are specific to the research question, the study design, as well as methodological feasibility. However, it is recommended that measures of TV viewing be used only if they have psychometric data to support their validity and reliability. Selecting measures that are valid and reliable enables us to examine with greater accuracy the influence of TV viewing on childhood overweight, as well as the efficacy of interventions designed to reduce TV viewing in children.
The prevalence and determinants of obesity in adults with intellectual disabilities
Authors: Melville C. A. , Hamilton S. , Hankey C. R. , Miller S. , Boyle S. 
Published: September 2006

SummaryPeople with intellectual disabilities experience significant health inequalities compared with the general population, including a shorter life expectancy and high levels of unmet health needs. Another accepted measure of health inequalities, the prevalence of obesity, has been shown to be higher in adults with intellectual disabilities than in the general population. While the factors contributing to the increased prevalence among adults with intellectual disabilities are not well understood, the high rates of obesity among younger adults highlight the need for further research involving children and adolescents with intellectual disabilities. To take forward the priorities for research and the development of effective, accessible services, there is a need for collaboration between professionals working in the fields of intellectual disabilities and obesity.
Charter Schools and Urban Regimes in Neoliberal Context: Making Workers and New Spaces in Metropolitan Atlanta
Authors: HANKINS KATHERINE B. , MARTIN DEBORAH G. 
Published: September 2006

AbstractIn this article, we demonstrate the neoliberalism and multiscalar economic perspective of the charter school movement in Atlanta, Georgia, through examination of news articles and editorials about charter schools in the Atlanta Journal‐Constitution from 1998 to 2004. We posit three interrelated dynamics which explain the editorial board’s interest in charter schools as part of a broader urban regime agenda. First, charter schools represent part of a neoliberal shift in education that parallels shifts in urban governance, emphasizing flexibility, public–private partnerships, and ‘market’‐oriented consumer choice and accountability. Second, the newspaper is issuing a challenge to educational structures, to adopt more neoliberal policies and shed a bureaucratic, liberal governance framework. Finally, we find critical evidence that the charter school movement draws on a multiscalar discourse which simultaneously references responsiveness to local, neighborhood needs, and at the same time highlights the economic imperatives of a global, competitive city to differentially skill students/workers in order to capture mobile and fractured (global) capital.
Cell‐matrix biology in vascular tissue engineering
Authors: Stephan Simon , Ball Stephen G. , Williamson Matthew , Bax Daniel V. , Lomas Amanda , Shuttleworth C. Adrian , Kielty Cay M. 
Published: September 2006

AbstractWe are developing biocompatible small‐calibre vascular substitutes based on polymeric scaffolds that incorporate cell‐matrix signals to enhance vascular cell attachment and function. Our graft scaffold comprises an outer electrostatically spun porous polyurethane layer seeded with smooth muscle cells, and a luminal polycaprolactone layer for endothelial cell attachment. Vascular cell adhesion properties of three vascular elastic fibre molecules, tropoelastin, fibrillin‐1 and fibulin‐5, have been defined, and adhesion fragments optimized. These fragments are being used to coat the scaffolds to enhance luminal endothelial cell attachment, and to regulate smooth muscle cell attachment and function. Tropoelastin‐based cell seeding materials are also being developed. In this way, vascular cell‐matrix biology is enhancing graft design.
Factors influencing osteological changes in the hands and fingers of rock climbers
Authors: Sylvester Adam D. , Christensen Angi M. , Kramer Patricia A. 
Published: September 2006

AbstractThis study examines the osteological changes in the hands and fingers of rock climbers that result from intense, long‐term mechanical stress placed on these bones. Specifically, it examines whether rock climbing leads to metacarpal and phalange modelling in the form of increased cortical thickness as well as joint changes associated with osteoarthritis. This study also attempts to identify specific climbing‐related factors that may influence these changes, including climbing intensity and frequency of different styles of climbing. Radiographs of both hands were taken for each participant and were scored for radiographic signs of osteoarthritis using an atlas method. Total width and medullary width were measured directly on radiographs using digital calipers and used to calculate cross‐sectional area and second moment of area based on a ring model. We compared 27 recreational rock climbers and 35 non‐climbers for four measures of bone strength and dimensions (cross‐sectional area, second moment of area, total width and medullary width) and osteoarthritis. A chi‐squared test for independence was used to compare climber and non‐climber osteoarthritis scores. For each measure of bone strength climbers and non‐climbers were compared using a manova test. Significant manova tests were followed by principal components analysis (PCA) and individual anova tests performed on principal components with eigenvalues greater than one. A second PCA was performed on the climber subsample and the first principal component was then used as the dependent variable in linear regression variable selection procedures to determine which climbing‐related variables affect bone thickness. The results suggest that climbers are not at an increased risk of developing osteoarthritis compared with non‐climbers. Climbers, however, do have greater cross‐sectional area as well as second moment of area. Greater total width, but not meduallary width, indicates that additional bone is deposited subperiosteally. The strength of the finger and hand bones are correlated with styles of climbing that emphasize athletic difficulty. Significant predictors include the highest levels achieved in bouldering and sport climbing.
Brain potentials indicate poor preparation for action in schizophrenia
Authors: Reuter Benedikt , Herzog Eva , Endrass Tanja , Kathmann Norbert 
Published: September 2006

AbstractImpaired antisaccade performance in schizophrenia (SZ) may originate from poor task preparation, suggested by low amplitudes of the contingent negative variation (CNV) before antisaccades. To dissociate components of preparation we measured the CNV in standard pro‐ and antisaccades and a stimulus preceding negativity (SPN) in delayed pro‐ and antisaccades. In healthy controls the SPN had lower amplitudes than the CNV, reflecting mere stimulus expectation in SPN and combined stimulus expectation and action readiness in CNV. SZ patients had lower CNV amplitudes than controls, but there was no reliable indication of a general SPN reduction, suggesting a particular impairment of action readiness. The CNV and SPN amplitudes of controls were larger if tasks had incongruent (anti) compared to congruent (pro) S‐R mappings. This difference was absent in SZ patients, suggesting a failure to activate specific resources for incongruent S‐R mappings.
Masked repetition priming and event‐related brain potentials: A new approach for tracking the time‐course of object perception
Authors: Eddy Marianna , Schmid Annette , Holcomb Phillip J. 
Published: September 2006

AbstractThis study reports a new approach to studying the time‐course of the perceptual processing of objects by combining for the first time the masked repetition priming technique with the recording of event‐related potentials (ERPs). In a semantic categorization task ERPs were recorded to repeated and unrelated target pictures of common objects that were immediately preceded by briefly presented pattern masked prime objects. Three sequential ERP effects were found between 100 and 650 ms post‐target onset. These effects included an early posterior positivity/anterior negativity (N/P190) that was suggested to reflect early feature processing in visual cortex. This early effect was followed by an anterior negativity (N300) that was suggested to reflect processing of object‐specific representations and finally by a widely distributed negativity (N400) that was argued to reflect more domain general semantic processing.
Breaking the silence: Brain–computer interfaces (BCI) for communication and motor control
Authors: Birbaumer Niels 
Published: September 2006

AbstractBrain–computer interfaces (BCI) allow control of computers or external devices with regulation of brain activity alone. Invasive BCIs, almost exclusively investigated in animal models using implanted electrodes in brain tissue, and noninvasive BCIs using electrophysiological recordings in humans are described. Clinical applications were reserved with few exceptions for the noninvasive approach: communication with the completely paralyzed and locked‐in syndrome with slow cortical potentials, sensorimotor rhythm and P300, and restoration of movement and cortical reorganization in high spinal cord lesions and chronic stroke. It was demonstrated that noninvasive EEG‐based BCIs allow brain‐derived communication in paralyzed and locked‐in patients but not in completely locked‐in patients. At present no firm conclusion about the clinical utility of BCI for the control of voluntary movement can be made. Invasive multielectrode BCIs in otherwise healthy animals allowed execution of reaching, grasping, and force variations based on spike patterns and extracellular field potentials. The newly developed fMRI‐BCIs and NIRS‐BCIs, like EEG BCIs, offer promise for the learned regulation of emotional disorders and also disorders of young children.
The psychosocial stress‐induced increase in salivary alpha‐amylase is independent of saliva flow rate
Authors: Rohleder Nicolas , Wolf Jutta M. , Maldonado Enrique F. , Kirschbaum Clemens 
Published: September 2006

AbstractThe stress response of salivary alpha‐amylase (sAA) has been suggested as an index for sympathetic nervous system activation. However, concurrent inhibition of the parasympathetic nervous system is discussed as a confounder due to suppression of saliva flow rate. Here we set out to test the influence of stress‐induced changes in flow rate on sAA secretion. Twenty‐six subjects underwent the Trier Social Stress Test and a control condition. Saliva was sampled by passive drooling or salivettes. Saliva flow rate, sAA levels and output, salivary cortisol, and heart rate variability were measured. Flow rate increased only when sampled by passive drooling. Stress‐induced increases in amylase levels were correlated with increases of amylase output but not with flow rate. Results indicate that flow rate is not a confounder of stress‐induced sAA activation and suggest that valid measurements of sAA can be obtained by salivettes without the need for assessment of flow rate.
Acute cortisol administration reduces subjective fatigue in healthy women
Authors: Tops Mattie , Van Peer Jacobien M. , Wijers Albertus A. , Korf Jakob 
Published: September 2006

AbstractTreatment with cortisol has been found to decrease fatigue and increase feelings of vigor in both patients and healthy male subjects. We obtained self‐reports of mood before 35 mg cortisol or placebo ingestion, 70 min later, and after the healthy female subjects performed cognitive tasks for 1 h in a double‐blind within‐subject study. Cortisol decreased fatigue, increased vigor, and tended to decrease tension. Effects on fatigue were largest after task performance, when fatigue had increased, suggesting that improvement of fatigue by cortisol is observed when subjects are fatigued. This is the first study to demonstrate improvements in fatigue in healthy female subjects; this is particularly relevant because of the high prevalence of hypocortisolimic fatigue syndromes in women and recent evidence that many psychiatric disorders may involve stress‐induced hypocortisolemia that is responsive to cortisol replacement.
Gamma band activity and its synchronization reflect the dysfunctional emotional processing in alexithymic persons
Authors: Matsumoto Atsushi , Ichikawa Yoko , Kanayama Noriaki , Ohira Hideki , Iidaka Tetsuya 
Published: September 2006

AbstractIn the present study, we investigated the gamma band response and its phase synchrony between electrodes in alexithymia, which is characterized by a disability in identifying and describing feelings. Individuals with high and low alexithymia scores were selected according to the scores on the 20‐item Toronto Alexithymia Scale. EEG was recorded from alexithymic and nonalexithymic persons viewing emotionally negative or neutral stimuli. Nonalexithymic persons exhibited increased gamma band power and phase synchronization at the 400–450‐ms time window when processing emotionally negative stimuli. Neither enhanced gamma band power nor phase synchronization was observed in alexithymic persons in the negative emotion condition. These results suggest that gamma band activity reflects emotional processing, and alexithymic persons may have a deficit in communication between brain regions or in the utilization of memory or emotional information during the processing of emotional stimuli.