Sport competition as a dynamical self-organizing system

The existence of structure in sport competition is implicated in the widespread practice of using the information gathered from a past contest to prepare for a future contest. Based on this reasoning, we previously analysed squash match-play for evidence of signature traits from among the stochastic relations between the various types of shot. The mixed findings from these analyses led us to re-analyse squash match-play as a dynamical system. Here, we extend this line of investigation with some suggestions as to how various sports might be described further within this theoretical framework. We offer some examples of dynamical interactions in dyadic (i.e. one vs one) and team (e.g. many vs many) sports, as well as some predictions from a dynamical systems analysis for these types of sports contests. This paper should serve to initiate further research into the complex interactions that occur in sport competition.     

法律界的性别歧视

性别平等的观念已经发展成这样一种程度:很多人确信男人和女人现在已经被平等对待了。不幸的是,当性别平等在社会的大部分领域已经成为现实时,性别歧视却仍然盛行在一个它最不可能出现的地方——法律界。     

Right hemisphere dysfunction in ADHD: visual hemispatial inattention and clinical subtype

The relationship between right hemisphere dysfunction and attention-deficit/hyperactivity disorder (ADHD) remains controversial. We administered a random letter cancellation test to 58 carefully selected adult patients meeting DSM-IV criteria for ADHD and 29 age- and education-matched controls. Patients with ADHD had a higher mean omission rate on the left side than the controls, and a greater percentage of ADHD patients than controls made more omissions on the left than on the right (L > R errors). ADHD patients who made L > R errors had lower performance IQ scores than ADHD patients who did not make L > R errors. However, ADHD patients who made L > R errors did not differ from ADHD patients who did not make L > R errors in ADHD subtype, medication response, or neuropsychological measures of attention, executive function, verbal memory, nonverbal memory, or academic achievement. Patients without a family history of ADHD were more likely to make L > R errors than patients with a family history of ADHD. This study provides support for the concept of right hemisphere dysfunction in a subset of patients with ADHD. However, ADHD patients who make L > R errors do not appear to represent a distinct clinical subgroup in terms of medication response, ADHD subtype, or neuropsychological test performance.     

Is child sexual abuse declining? Evidence from a population-based survey of men and women in Australia

OBJECTIVE: Substantiated cases of child sexual abuse (CSA) in the United States have declined significantly over the past decade. This may, or may not, reflect change in the underlying rate in the general population. This study examines age-cohort differences in the prevalence of self-reported CSA experiences of men and women aged 18-59 years in a community-based sample from a comparable western nation. METHOD: In April 2000, we completed a cross-sectional, telephone-based survey of a randomly selected national sample of men and women in Australia. Volunteers (876 males, 908 females) answered a range of questions about health status and sexuality, including unwanted sexual experiences before the age of 16 years. Of selected adults with publicly-listed telephone numbers, 61% agreed to participate. There were few differences between the volunteers and the Australian population on demographic variables and health indicators. RESULTS: Non-penetrative CSA was twice as common among women (33.6%) than men (15.9%). Approximately 12% of women and 4% of men reported unwanted penetrative experiences. CSA was reported significantly less often by younger males, with a linear decline from the oldest to youngest men. Among all females who had intercourse before age 16, older women were much more likely than younger women to say they were an unwilling partner on the first occasion. If first intercourse occurred at age 16 or later, there were no age-cohort differences in risk of first-time abuse. Self-reported "openness" and "comfort" during the telephone interviews was not systematically related to prevalence of CSA. CONCLUSION: These population-based findings provide evidence of a decline in the underlying rate of CSA in Australia. Although every measure of CSA inevitably is flawed to some extent, these trends in self-report complement official statistics that show substantial decline in recent years.     

Processing of rapid auditory stimuli in school-age children referred for evaluation of learning disorders

Tallal hypothesized that reading disabled children have a domain-general deficit in processing rapidly occurring auditory stimuli that degrades speech perception, thereby limiting phonologic awareness and thus reading acquisition. She predicted they would be disproportionately affected by rapidly presented auditory stimuli. In this study, one hundred 7- to 11-year-old children with learning impairment (LI) and 243 non-learning impaired (NLI) children were evaluated on a two-tone auditory discrimination paradigm. LI committed more errors, but effects of timing were comparable. The same result was obtained for a subsample of good and poor readers. Task performance predicted reading, spelling, and calculation. Neural processes underlying perception of speech and other auditory stimuli may be less effective in poor readers; however, contrary to Tallal's hypothesis, rate may not be specifically affected.     

Neurodevelopmental characteristics of children with learning impairments classified according to the double-deficit hypothesis

The double-deficit model has been examined primarily in relation to reading. We investigated whether children classified according to the double-deficit model would exhibit differences in other neuropsychological domains. Children referred for learning problems (N = 188), ages 7 to 11, were classified by double-deficit subtype. Only three of the four groups predicted by the model could be identified. There were no group differences in IQ or attention problems. The three groups showed different neuropsychological profiles, involving functional domains other than reading and language. Differences also emerged in nonverbal low-level information processing. The double-deficit group was generally most severely affected. The double-deficit groupings identify children with different neuropsychological profiles and variation in the efficiency of basic online information processing, extending beyond the oral and written language domain.     

Practical considerations when using pedometers to assess physical activity in population studies: lessons from the Burnie Take Heart Study

The aim of this study was to summarize both practical and methodological issues in using pedometers to assess physical activity in a large epidemiologic study. As part of a population-based survey of cardiovascular disease risk factors, physical activity was assessed using pedometers and activity diaries in 775 men and women ages 25-64 years who were residents of Burnie, Tasmania, 1998-99. Common data problems were classified by type. The frequency of each problem and the methods used to identify it are reported along with strategies to correct or prevent each problem type. Pedometer data from 15 (1.9%) participants could not be used due to errors in completing the pedometer protocol. Among 760 participants with usable data, the median number of steps was 9,729 for men and 10,388 for women. Pedometer steps per day were modestly correlated (r = .20, p < .0001) with the duration of pedometer wear, which ranged from 4.50 to 21.75 hr. Adjustment for wear time, however, did not alter observed correlations between pedometer steps and cardiovascular risk factors. The authors conclude that pedometers can be used in large population studies with a relatively low frequency of data errors. However guidelines for consistent data collection and interpretation are needed.     

Microfluidic endothelial cell culture model to replicate disturbed flow conditions seen in atherosclerosis susceptible regions

Atherosclerotic lesions occur non-randomly at vascular niches in bends and bifurcations where fluid flow can be characterized as "disturbed" (low shear stress with both forward and retrograde flow). Endothelial cells (ECs) at these locations experience significantly lower average shear stress without change in the levels of pressure or strain, which affects the local balance in mechanical stresses. Common in vitro models of atherosclerosis focus primarily on shear stress without accounting for pressure and strain loading. To overcome this limitation, we used our microfluidic endothelial cell culture model (ECCM) to achieve accurate replication of pressure, strain, and shear stress waveforms associated with both normal flow seen in straight sections of arteries and disturbed flow seen in the abdominal aorta in the infrarenal segment at the wall distal to the inferior mesenteric artery (IMA), which is associated with high incidence of atherosclerotic lesion formation. Human aortic endothelial cells (HAECs) were cultured within the ECCM under both normal and disturbed flow and evaluated for cell shape, cytoskeletal alignment, endothelial barrier function, and inflammation using immunofluorescence microscopy and flow cytometry. Results clearly demonstrate quantifiable differences between cells cultured under disturbed flow conditions, which are cuboidal with short and randomly oriented actin microfilaments and show intermittent expression of β-Catenin and cells cultured under normal flow. However, in the absence of pro-inflammatory stimulation, the levels of expression of activation markers: intra cellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), platelet endothelial cell adhesion molecule-1 (PECAM-1), and vascular endothelial cell growth factor - receptor 2 (VEGF-R2) known to be involved in the initiation of plaque formation were only slightly higher in HAECs cultured under disturbed flow in comparison to cells cultured under normal flow.