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1.
Very preterm children are at increased risk of reduced processing speed at 5 years of age,predicted by typical complications of prematurity and prenatal smoking 下载免费PDF全文
2.
用“点值法”对健康工人473例[轻体力劳动工人(简称轻工)248例,重体力劳动工人(简称重工)225例]。作了流量一容积曲线和常规通气功能检查。结果表明:重工男女在40岁以后其高肺容积流量下降,30岁以后低肺容积流量上升,而且这些改变有随年龄增长而更加明显的倾向;轻工仅有个别年龄组的低肺容积流量上升。对7名健康坐位工作者模拟劳动的前倾姿势作多次通气功能检查,亦有明显高肺容积流量下降和低肺容积流量上升的现象,这一事实提示波速学说亦可应用于颈和躯干前倾进行重体力劳动工人的通气行为。 相似文献
3.
There is overwhelming evidence for the existence of substantial genetic influences on individual differences in general and specific cognitive abilities, especially in adults. The actual localization and identification of genes underlying variation in cognitive abilities and intelligence has only just started, however. Successes are currently limited to neurological mutations with rather severe cognitive effects. The current approaches to trace genes responsible for variation in the normal ranges of cognitive ability consist of large scale linkage and association studies. These are hampered by the usual problems of low statistical power to detect quantitative trait loci (QTLs) of small effect. One strategy to boost the power of genomic searches is to employ endophenotypes of cognition derived from the booming field of cognitive neuroscienceThis special issue of Behavior Genetics reports on one of the first genome-wide association studies for general IQ. A second paper summarizes candidate genes for cognition, based on animal studies. A series of papers then introduces two additional levels of analysis in the black box between genes and cognitive ability: (1) behavioral measures of information-processing speed (inspection time, reaction time, rapid naming) and working memory capacity (performance on on single or dual tasks of verbal and spatio-visual working memory), and (2) electrophyiosological derived measures of brain function (e.g., event-related potentials). The obvious way to assess the reliability and validity of these endophenotypes and their usefulness in the search for cognitive ability genes is through the examination of their genetic architecture in twin family studies. Papers in this special issue show that much of the association between intelligence and speed-of-information processing/brain function is due to a common gene or set of genes, and thereby demonstrate the usefulness of considering these measures in gene-hunting studies for IQ. 相似文献
4.
We hypothesized that the history of contraction would affect the in vivo quadriceps torque-velocity relationship. We examined
the quadriceps torque-velocity relationship of the human knee extensors at the descending and ascending limb of the torque-position
relationship by initiating the knee extension at a knee angle position of 1.39 rad (80°) or 0.87 rad (50°) over a 0.52 rad
(30°) range of motion under conditions of constant or linearly increasing velocity. Maximal voluntary isometric knee extension
torque (M0) was measured at 1.87 rad, 0.87 rad, and 0.35 rad, and concentric torque was measured. The subjects carried out ten maximal
knee extensions at ten distinct velocities, each velocity ranging between 0.52 rad·s–1 to 5.24 rad·s–1 in steps of 0.52 rad·s–1. Peak concentric torque was measured and mean torque calculated from the respective torque-time curves. Peak or mean torque,
computed from the individual torque-time curves, and velocity data were fitted to the Hill equation under the four experimental
conditions and the curve parameters computed. The M0 was similar at 0.87 rad and 1.39 rad, but it was significantly lower at 0.35 rad. In the low-velocity domain of the torque-velocity
curve where a plateau normally occurs, peak torque was always lower than M0. Peak and mean torque were significantly greater under linearly increasing velocity conditions and the 1.39 rad starting
knee position. Mean torque but not peak torque data could be well fitted to the Hill equation and the two computations resulted
in significantly different Hill curve parameters including the concavity ratio, peak power, and maximal angular velocity.
We concluded that the history of contraction significantly modifies the in vivo torque-velocity relationship of the human
quadriceps muscle. Muscle mechanics and not neural factors may have accounted for the inconsistencies in the human torque-velocity
relationships reported previously.
Electronic Publication 相似文献
5.
Individual differences in inspection time explain about 20% of IQ test variance. To determine whether the association between inspection time and IQ is mediated by common genes or by a common environmental factor, inspection time and IQ were assessed in an extended twin design. Data from 688 participants from 271 families were collected as part of a large ongoing project on the genetics of adult brain function and cognition. The sample consisted of a young adult cohort (mean age 26.2 years) and an older adult cohort (mean age 50.4 years). IQ was assessed with the Dutch version of the WAIS-3R. Inspection time was measured in the so-called -paradigm, in which a subject is asked to decide which leg of the -figure is longest at varying display times of the -figure. The number of correct inspections per second (i.e., the reciprocal of inspection time) was used to index perceptual speed. For Verbal IQ and Performance IQ, heritabilities were 85% and 69%, respectively. For perceptual speed, 46% of the total variance was explained by genetic variance. No differences in heritability estimates across age cohorts or sexes were found. Across the whole sample, a significant phenotypic correlation was found between perceptual speed and Verbal IQ (0.19) and between perceptual speed and Performance IQ (0.27). These correlations were entirely due to a common genetic factor that accounted for 10% of the genetic variance in verbal IQ and for 22% of the genetic variance in performance IQ. This factor is hypothesized to reflect the influence of genetic factors that determine axonal myelination in the central nervous system. 相似文献
6.
Studies on adults have suggested that a deterioration in performance (within session vigilance decrement) on a continuous performance task may be related to individual differences in baseline levels of electrodermal activity (electrodermal lability). This study investigated this relationship in 153 children, aged 9–16 years. A significant vigilance decrement was observed, as indicated by average decreases in perceptual sensitivity (d') over an 11.5-min time period. Although electrodermal labiles were overall more perceptually sensitive than electrodermal stabiles, results did not support the premise that the performance of stabiles decreases over time more than that of labiles. Performance on other cognitive tasks, involving tests of perceptual speed ability, did not appear to be highly related to vigilance performance. However labiles were not only better able to sustain their attention, but also performed better and faster on these cognitive tasks. 相似文献
7.
Male mating speed as a component of fitness inDrosophila 总被引:1,自引:0,他引:1
P. A. Parsons 《Behavior genetics》1974,4(4):395-404
From a survey of published data on the genusDrosophila, it is clear that male mating speed or male virility is probably the most important component of fitness. Rapid matings tend to be controlled by the male genotype, while the genotype of the female may assume importance for slower matings. Where data exist, male mating speed is subject to directional selection in the direction of rapid speed, as would be expected for an important component of fitness.Supported by the Australian Research Grants Committee. 相似文献
8.
Petter Fagerberg Evangelia Charmandari Christos Diou Rachel Heimeier Youla Karavidopoulou Penio Kassari Evangelia Koukoula Irini Lekka Nicos Maglaveras Christos Maramis Ioannis Pagkalos Vasileios Papapanagiotou Katerina Riviou Ioannis Sarafis Athanasia Tragomalou Ioannis Ioakimidis 《Nutrients》2021,13(3)
Fast self-reported eating rate (SRER) has been associated with increased adiposity in children and adults. No studies have been conducted among high-school students, and SRER has not been validated vs. objective eating rate (OBER) in such populations. The objectives were to investigate (among high-school student populations) the association between OBER and BMI z-scores (BMIz), the validity of SRER vs. OBER, and potential differences in BMIz between SRER categories. Three studies were conducted. Study 1 included 116 Swedish students (mean ± SD age: 16.5 ± 0.8, 59% females) who were eating school lunch. Food intake and meal duration were objectively recorded, and OBER was calculated. Additionally, students provided SRER. Study 2 included students (n = 50, mean ± SD age: 16.7 ± 0.6, 58% females) from Study 1 who ate another objectively recorded school lunch. Study 3 included 1832 high-school students (mean ± SD age: 15.8 ± 0.9, 51% females) from Sweden (n = 748) and Greece (n = 1084) who provided SRER. In Study 1, students with BMIz ≥ 0 had faster OBER vs. students with BMIz < 0 (mean difference: +7.7 g/min or +27%, p = 0.012), while students with fast SRER had higher OBER vs. students with slow SRER (mean difference: +13.7 g/min or +56%, p = 0.001). However, there was “minimal” agreement between SRER and OBER categories (κ = 0.31, p < 0.001). In Study 2, OBER during lunch 1 had a “large” correlation with OBER during lunch 2 (r = 0.75, p < 0.001). In Study 3, fast SRER students had higher BMIz vs. slow SRER students (mean difference: 0.37, p < 0.001). Similar observations were found among both Swedish and Greek students. For the first time in high-school students, we confirm the association between fast eating and increased adiposity. Our validation analysis suggests that SRER could be used as a proxy for OBER in studies with large sample sizes on a group level. With smaller samples, OBER should be used instead. To assess eating rate on an individual level, OBER can be used while SRER should be avoided. 相似文献
9.
《Health & place》2021
Twenty miles per hour (mph) speed limits can impact the health of the public (e.g., road safety, active travel). However, a better understanding of how individuals experience 20mph limits is required, to ensure interventions are cognisant of perceptions and potential un/intended outcomes. Focus groups (n = 9, 60 participants) to explore the Belfast 20mph intervention highlighted divergent perspectives and experiences including: 12 mechanisms (e.g., limited awareness), 15 pathways (e.g., reduced driving speed→improved liveability) and 10 public health outcomes (e.g., increased cyclist safety). Future interventions should consider un/intended outcomes and implement strategies to enhance effectiveness and mitigate harms (e.g., through training, enforcement). 相似文献
10.
《Fu? & Sprunggelenk》2021,19(3):154-160
Case reportA 32 years old male patient slipped while going downhill and injured his right foot. The next day X-rays were taken in which no bony injury was seen. Because of persistent complaints additional diagnostic by MRI and CT were performed. These showed a displaced fracture of the sustentaculum tali. The sustentaculum tali was fixed with screws. The fracture healed with a congruent articular surface and good functional outcome.ConclusionFractures of the sustentaculum tali are rare and are overseen frequently because of overlapping structures on X-rays. Even low energy trauma can cause these fractures in young patients. In patients with persistent complaints of the foot an additional cross-sectional diagnostic is strongly recommended. 相似文献