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141.
The purpose of this study was to reproduce and extend two earlier studies of the effects of human exposure to 50 Hz magnetic fields (MF). In a recent paper, we described results of two double-blind investigations performed to examine effects of 100 microT(rms) 50 Hz MF exposure on psychological parameters in the same group of healthy human volunteers. In each exposure session, at 1 week intervals, with sham, continuous, and intermittent (15 s ON/OFF cycles) MF conditions, mood ratings, performance measures, and electrophysiological measures were taken. In the first study, significant amplitude changes were observed in the event-related brain potentials (ERP) recorded during a dichotic listening task. In the second study, latency and reaction time (RT) slowing were seen on a visual discrimination task (P(300) paradigm). Although these results were little related to the number of parameters analysed, they indicate that low level 50 Hz MF might have a slight influence on ERP and RT under specific circumstances of sustained attention. Before concluding that moderately strong MF exposure can influence cognitive function, previous results should be replicated, using the same paradigms with another group of healthy volunteers. In the present study, 18 healthy subjects were exposed to three experimental sessions of 30 min each, given at 1 week intervals. The sessions consisted of continuous 100 microT(rms) 50 Hz MF exposure, sham condition, and bright light (5000 lux) exposure. The study was performed double-blind, with the exposure order counter-balanced. The data on mood, ERP, RT, and other performance measures did not show any differences among the sham exposure, light exposure, and MF exposure conditions. The results of this study do not support the hypothesis that extremely low frequency (ELF) MF exposure affects the brain's electrical activity or cognitive function at field strength (100 microT(rms)) similar to that found in very close proximity of some household and industrial electrical appliances and well in excess of the average MF strength (c. 0.1 microT) found in homes. The sensitivity of the experiment was possibly not sufficient to detect an effect at this relatively low MF, and larger sample sizes would be required in further studies.  相似文献   
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Linguistic evidence suggests that West Asia and Central Asia have been the two major geographical sources of genes in the contemporary Indian gene pool. To test the nature and extent of similarities in the gene pools of these regions we have collected DNA samples from four ethnic populations of northern India, and have screened these samples for a set of 18 Y-chromosome polymorphic markers (12 unique event polymorphisms and six short tandem repeats). These data from Indian populations have been analysed in conjunction with published data from several West Asian and Central Asian populations. Our analyses have revealed traces of population movement from Central Asia and West Asia into India. Two haplogroups, HG-3 and HG-9, which are known to have arisen in the Central Asian region, are found in reasonably high frequencies (41.7% and 14.3% respectively) in the study populations. The ages estimated for these two haplogroups are less in the Indian populations than those estimated from data on Middle Eastern populations. A neighbour-joining tree based on Y-haplogroup frequencies shows that the North Indians are genetically placed between the West Asian and Central Asian populations. This is consistent with gene flow from West Asia and Central Asia into India.  相似文献   
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Thirty-two multiparous Holando argentino cows in mid lactation were randomly assigned to two treatments: control or HFF (hydrogenated fish fat) at Rafaela, 31° 11’ South, during summer 1997/1998, to evaluate the effect of using HFF as a supplement under grazing conditions. Animals in both treatments grazed an alfalfa pasture, and were confined from 1000 hours to 1700 hours daily in a shaded pen where water was provided ad libitum. During each milking, animals in the control group received 3.73 kg dry matter per cow each day (DM cow–1 day–1) concentrate (15% crude protein; 8.69 MJ energy for location/kg DM). Cows in the HFF group received 3.25 kg DM cow–1 day–1 concentrate, plus 0.200 kg DM cow–1 day–1 HFF. Both diets presented similar energy, protein and neutral detergent fibre contents. The trial was performed during a strong ”El Niño” event, which resulted in a total rainfall of 396.3 mm (80% higher than normal). The mean temperature was 23.7 (SD 3.2)°C and the mean temperature humidity index was 72.9 (SD 4.96). Production data were analysed using a completely randomised design with analysis of covariance. Supplementation with HFF produced an increase in daily milk production (26.4 (SD 2.46) l/cow compared to 23.9 (SD 2.68) l/cow for the controls; P<0.05). Milk fat production was higher for HFF (P<0.05): 941 (SD 96) g cow–1 day–1 as compared to controls, which yielded 846 (SD 95) g cow–1 day–1. Milk protein yields also differed significantly (P<0.05), the respective values for HFF and controls being 795 (SD 72) g cow–1 day–1 and 715 (SD 83) g cow–1 day–1. It was concluded that hydrogenated fish fat could be a good ingredient to sustain high yields and elevated maintenance requirements in a grazing system during hot conditions.  相似文献   
146.
Event Services in High Performance Systems   总被引:2,自引:0,他引:2  
The Internet and the Grid are changing the face of high performance computing. Rather than tightly-coupled SPMD-style components running in a single cluster, on a parallel machine, or even on the Internet programmed in MPI, applications are evolving into sets of cooperating components scattered across diverse computational elements. These components may run on different operating systems and hardware platforms and may be written by different organizations in different languages. Complete applications are constructed by assembling these components in a plug-and-play fashion. This new vision for high performance computing demands features and characteristics not easily provided by traditional high-performance communications middleware. In response to these needs, we have developed ECho, a high-performance event-delivery middleware that meets the new demands of the Grid environment. ECho provides efficient binary transmission of event data with unique features that support data-type discovery and enterprise-scale application evolution. We present measurements detailing ECho's performance to show that ECho significantly outperforms other systems intended to provide this functionality and provides throughput and latency comparable to the most efficient middleware infrastructures available.  相似文献   
147.
通过对20多年来ENSO事件的发生与杉木人工林胸径生长关系的研究,探讨全球气候异常对林生长动态的影响。结果表明:厄尔尼诺及南方涛动杉木人工林胸径生长存在显著影响(α=0.10)。以南方涛动为自变量,建立杉木人工林胸径生长模型,模拟精度达93.61%,为林木生长预测提供了新途径。  相似文献   
148.
The study evaluated the safety, tolerability, pharmacokinetics (PK) and anti-drug antibody (ADA) of the recombinant human thymosin β4 (NL005) for single and multiple intravenous injections in healthy subjects. Seven cohorts, with 54 healthy subjects, were given a single intravenous dose of NL005 or placebo and were observed for 28 days. The cohorts received ascending doses of either 0.05, 0.25, 0.5, 2.0, 5.0, 12.5 or 25.0 μg/kg in the single-dose trial. A total of 30 healthy subjects were randomly enrolled in the multiple-dose trial, and 3 cohorts (0.5, 2.0 and 5.0 μg/kg) were administered once human thymosin β4 daily for 10 days and observed for 28 days. The adverse events were mild to moderate in intensity. There were no dose-limiting toxicities or serious adverse events. The plasma concentration, maximum peak concentration (Cmax) and AUC of each dose group increased with the increase in the dose. The tendency of terminal clearance in each dose group was consistent, and there was no obvious accumulation after continuous administration. Thus, the drug can be concluded to be well tolerated and safe in healthy people and suitable for use in a clinical study for the treatment of acute myocardial infarction.  相似文献   
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150.
Tropical rainforests in Africa are one of the most under-researched regions in the world, but research in the Amazonian rainforest suggests potential vulnerability to climate change. Using the large ensemble of Atmosphere-only general circulation model (AGCM) simulations within the weather@home project, statistics of precipitation in the dry season of the Congo Basin rainforest are analysed. By validating the model simulation against observations, we could identify a good model performance for the June, July, August (JJA) dry season, but this result does need to be taken with caution as observed data are of poor quality. Additional validation methods have been used to investigate the applicability of probabilistic event attribution analysis from large model ensembles to a tropical region, in this case the Congo Basin. These methods corroborate the confidence in the model, leading us to believe the attribution result to be robust. That is, that there are no significant changes in the risk of low precipitation extremes during this dry season (JJA) precipitation in the Congo Basin. Results for the December, January, February dry season are less clear. The study highlights that attribution analysis has the potential to provide valuable scientific evidence of recent or anticipated climatological changes, especially in regions with sparse observational data and unclear projections of future changes. However, the strong influence of sea surface temperature teleconnection patterns on tropical precipitation provides more challenges in the set up of attribution studies than midlatitude rainfall.  相似文献   
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