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991.
Vedat Cinar Rasim Mogulkoc Abdulkerim Kasim Baltaci Ozgur Bostanci 《Biological trace element research》2010,133(1):29-33
This study was performed to determine how the calcium supplementation for a 4-week period affects the glucose and insulin
levels at rest and at exhaustion in athletes. This is a 4-week study performed on 30 healthy subjects varying between 18 and
22 ages. Subjects were separated into three groups: first group (group supplemented with calcium, sedentary group), second
group (calcium supplementations + exercise group), and third group (training group). Glucose and insulin parameters of the
groups were measured four times, at rest and exhaustion in the beginning of the research and at rest and exhaustion after
the end of 4 weeks application period. Exhaustion measurements both before and after the supplementations significantly decreased
in compared to rest measurements in terms of insulin (p < 0.05). Significant difference was not determined in the glucose values of groups. In terms of glucose, values increased
in all of the three groups occurred with exercise both before and after the supplementation by exercise and exhaustion (p < 0.05). The results of our study indicate that calcium gluconate supplementations for 4 weeks in sedentary subjects and
athletes did not significantly affect plasma insulin levels at rest and exhaustion. However, glucose levels were affected
by calcium supplementation and exhausting exercise in athletes. 相似文献
992.
993.
Zong-wen Pang Jing-juan Liang Xiao-juan Qin Ji-rui Wang Jia-xun Feng Ri-bo Huang 《Biotechnology letters》2010,32(12):1847-1851
Kluyveromyces marxianus GX-15 was mutated multiple times by alternately treatment with UV irradiation and NTG for two cycles. Four mutant strains
with improved ethanol yield were obtained. The maximum ethanol concentration, ethanol yield coefficient and theoretical ethanol
yield of the best mutant strain, GX-UN120, was 69 g/l, 0.46 g/g and 91%, respectively, when fermenting 150 g glucose/l at
40°C. The corresponding values for GX-15 were 58 g/l, 0.39 g/g and 76%, respectively. GX-UN120 grew well in 11% (v/v) of ethanol,
while GX-15 could not grow when ethanol was greater than 8% (v/v). 相似文献
994.
995.
A new species, Allium pseudosenescens, belonging to sect. Rhizirideum (Alliaceae), is described from northeastern China. It is easily distinguished from A. senescens by the slender pedicels, pale pink perianths, narrower tepals and ovaries, yellowish anthers, and sometimes toothed subulate
filaments. Also, A. senescens var. minus in sect. Rhizirideum is raised to the rank of species, as A. minus. This Korean endemic taxon is shown to be a biologically distinct species based on morphological and cytological characters.
Taxonomic keys for the species of Allium sect. Rhizirideum in northeastern China and Korea are provided. 相似文献
996.
For animals to carry out a wide range of detection, recognition and navigation tasks, visual motion signals are crucial. The
encoding of motion information has therefore, attracted much attention in the experimental and computational study of brain
function. Two main alternative mechanisms have been proposed on the basis of behavioural and physiological experiments. On
one hand, correlation-type and motion energy detectors are simple and efficient in the design of their basic mechanism but
are tuned to temporal frequency rather than to speed. On other hand, gradient-type motion detectors directly represent an
estimate of speed, but may require more demanding processing mechanisms. We demonstrate here how the temporal frequency dependence
observed for sine-wave gratings can disappear for less constrained stimuli, to be replaced by responses reflecting speed for
stimuli like square waves when a phase-sensitive detection mechanism is employed. We conclude from these observations that
temporal frequency tuning is not necessarily a limitation for motion vision based on correlation detectors, and more generally
demonstrate in view of the typical Fourier composition of natural scenes, that correlation detectors operating in such environments
can encode image speed. In the context of our results, we discuss the implications of the loss of phase sensitivity inherent
in using a linear system approach to describe neural processing. 相似文献
997.
Seasonal dynamics of zooplankton in a shallow eutrophic,man-made hyposaline lake in Delhi (India): role of environmental factors 总被引:1,自引:0,他引:1
Old Fort Lake, a small (1.6 ha), shallow, and recreational water body in Delhi (India) was studied through monthly surveys
in two consecutive years (January, 2000–December, 2001). Precipitation is the major source of water for this closed basin
lake. In addition, ground water is used for replenishing the lake regularly. This alkaline, hyposaline hard water lake contains
very high ionic concentration, especially of nitrates. Based on overall ionic composition, this lake can be categorized as
chloride–sulfate alkaline waters with the anion sequence dominated by SO4
2− > Cl− > HCO3
−, and the cations by Mg++ > Ca++. The overall seasonal variability in physicochemical profile was largely regulated by the annual cycle of evaporation and
precipitation, whereas the ground water largely influences its water quality. The lake exhibited phytoplankton-dominated turbid
state due to dominance of the blue green alga, Microcystis aeruginosa. The persistent cyanobacterial blooms and the elevated nutrient levels are indicative of the cultural eutrophication of the
lake. This study focuses on the relative importance of eutrophic vis-à-vis hyposaline conditions in determining the structure
and seasonal dynamics of zooplankton species assemblages. A total of 52 zooplankton species were recorded and rotifers dominated
the community structure qualitatively as well as quantitatively. The genus Brachionus comprised a significant component of zooplankton community with B. plicatilis as the most dominant species. The other common taxa were B. quadridentatus, B. angularis, Lecane grandis, L. thalera, L. punctata, Mesocyclops sp., and Alona rectangula. Multivariate data analysis techniques, Canonical Correspondence Analysis (CCA) along with Monte Carlo Permutation Tests
were used to determine the minimum number of environmental factors that could explain statistically significant (P < 0.05) proportions of variation in the species data. The significant variables selected by CCA were NH3–N followed by percent saturation of DO, COD, SS, BOD, NO2–N, rainfall, silicates, and PO4–P. The results indicate that the seasonal succession patterns of the zooplankton species were largely controlled by physicochemical
factors related directly or indirectly to the process of eutrophication, whereas hyposaline conditions in the lake determined
the characteristic species composition.
Guest Editors: J. John & B. Timms
Salt Lake Research: Biodiversity and Conservation—Selected papers from the 9th Conference of the International Society for
Salt Lake Research 相似文献
998.
Dogs demonstrate an age-related cognitive decline, which may be related to a decrease in the concentration of omega-3 polyunsaturated
fatty acids (n-3 PUFA) in the brain. Medium chain triglycerides (MCT) increase fatty acid oxidation, and it has been suggested that this
may raise brain n-3 PUFA levels by increasing mobilization of n-3 PUFA from adipose tissue to the brain. The goal of the present study was to determine whether dietary MCT would raise n-3 PUFA concentrations in the brains of aged dogs. Eight Beagle dogs were randomized to a control diet (n = 4) or an MCT (AC-1203) enriched diet (n = 4) for 2 months. The animals were then euthanized and the parietal cortex was removed for phospholipid, cholesterol and
fatty acid determinations by gas-chromatography. Dietary enrichment with MCT (AC-1203) resulted in a significant increase
in brain phospholipid and total lipid concentrations (P < 0.05). In particular, n-3 PUFA within the phospholipid, unesterified fatty acid, and total lipid fractions were elevated in AC-1203 treated subjects
as compared to controls (P < 0.05). Brain cholesterol concentrations did not differ significantly between the groups (P > 0.05). These results indicate that dietary enrichment with MCT, raises n-3 PUFA concentrations in the parietal cortex of aged dogs. 相似文献
999.
Simultaneous electricity generation and selenium removal was evaluated in single-chamber microbial fuel cells (MFCs) with
acetate and glucose as carbon sources. Power output was not affected by selenite up to 125 mg l−1 with glucose as substrate. Coulombic efficiencies of MFCs with glucose increased from 25% to 38% at 150 mg Se l−1. About 99% of 50 and 200 mg Se l−1 selenite was removed in 48 and 72 h for MFCs fed with acetate and glucose, respectively, demonstrating the potential of using
MFC technology for Se remediation. 相似文献
1000.
Consumption of aphids by spiders and the effect of additional prey: evidence from microcosm experiments 总被引:1,自引:0,他引:1
Spiders are common generalist predators in agroecosystems and have been suggested to lower herbivore abundance in crops. It
is not clear, however, if spiders can effectively suppress pest populations, and if so, by what mechanisms. In a microcosm
experiment, we examined the consumption of the bird cherry-oat aphid, Rhopalosiphum padi L. (Homoptera: Aphididae), a pest species in wheat fields, by three spider species that differ in their hunting methods.
We then tested the effect of additional prey type on the ability of erigonid spiders to reduce aphids. In a 48-h experiment
Mermessus denticulatus (Banks) (Araneae: Linyphiidae; Erigoninae) consumed more aphids than did Enoplognatha gemina Bosmans and Van Keer (Araneae: Theridiidae) and Bathyphantes cf. extricatus (O·P.-Cambridge) (Araneae: Linyphiidae; Linyphiinae). This difference may be due to the ability of erigonids to forage actively
on the vegetation in addition to using their webs to catch prey. In a 7-week experiment, we provided springtails (Collembola)
in high and low densities as additional prey to mated erigonids, prior to aphid introduction. Spiders in the low-density springtail
treatment built more webs on the vegetation, and caused a 50% reduction in aphid populations. There were significantly fewer
aphids in the low-density springtail treatment, but not in the high-density treatment, in comparison to the control (high-density
springtails without spiders). The results suggest that additional prey density affects predatory interactions between M. denticulatus and R. padi and that erigonids, which occur in high densities in wheat fields in the Negev desert, may be involved in aphid suppression
in these agroecosystems.
相似文献
Efrat Gavish-RegevEmail: |