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121.
Ontogenetic approach reveals how cognitive capability and motivation shape prey‐searching behavior in Pholcus phalangioides cellar spiders
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Joseph T. Kilmer Zachary S. Havens Rafael L. Rodríguez 《Ethology : formerly Zeitschrift fur Tierpsychologie》2018,124(9):657-666
An important part of understanding the evolution of behavior is understanding how and why behavior develops and changes throughout ontogeny. Patterns of behavior are shaped by an animal's capabilities as well as its motivations, both of which are subject to selection. We ran an experiment to see how spiders' efforts to recover lost prey change with age and to determine the relative contributions of shifts in capability and motivation. We found that as spiders mature, they spend less time searching to recover lost prey, and they discriminate less between prey of different sizes. We also found that even the youngest, least experienced spiders are cognitively equipped to search for lost prey. Thus, predatory behavior in spiders fluctuated primarily with each age group's motivations to capture and consume prey, and did not seem to be hindered by behavioral or cognitive limitations at young ages. 相似文献
122.
Restriction mapping is used to estimate nucleotide sequence polymorphism
when the regions to be studied are too long or too numerous to be
sequenced. Restriction mapping is less costly than DNA sequencing, but it
does not allow direct measurement of underlying nucleotide polymorphism. It
is therefore useful to be able to estimate underlying nucleotide
polymorphism from observations of polymorphism in restriction maps, as this
offers some of the resolution afforded by DNA sequencing at a reduced cost.
Previous estimators of underlying nucleotide polymorphism have assumed that
each restriction-enzyme- binding site contains, at most, a single
polymorphic nucleotide position (the low-polymorphism-frequency
assumption), and this assumption has placed an upper limit on the level of
polymorphism that can be resolved by these estimators. The present study
documents an estimator which allows relaxation of this assumption. The new
estimator more accurately estimates underlying nucleotide polymorphism when
the polymorphism level is high enough to falsify the low-polymorphism-
frequency assumption. The new estimator therefore yields good results for
data sets that are too divergent for analysis by present methods.
相似文献
123.
Phosphorus (P) dynamics in large shallow lakes are greatly influenced by physical processes such as wind-driven sediment resuspension,
at times scales from hours to years. Results from long-term (30 year) research on Lake Okeechobee, Florida (area 1,730 km2, mean depth 2.7 m) illustrate key features of these P dynamics. Variations in wind velocity result in changes in water column
transparency, suspended solids, and total P (TP). In summer there are diurnal changes in TP associated with afternoon winds,
and in winter, when strong winds occur for multiple days, monthly average TP remains high compared to summer. The magnitude
of daily and seasonal TP changes can exceed 100 μg l−1. Hurricanes and tropical storms also cause extreme changes in TP that are superimposed on seasonal dynamics. When a hurricane
passed 80 km south of the lake in October 1999, mean pelagic TP increased from 88 to 222 μg l−1. During large resuspension events, light attenuation is substantially increased, and this influences the biomass and spatial
extent of submerged plants, as well as water column TP. In Lake Okeechobee, TP concentrations typically are ∼20 μg l−1 when submerged plants are dense, and soluble reactive P concentrations are reduced below detection, perhaps by the periphyton
and plant uptake and by precipitation with calcium at high pH. In contrast, TP exceeds 50 μg l−1 when submerged plants and periphyton are absent due to prolonged deep water, and phytoplankton biomass and algal bloom frequency
both are increased. In Lake Okeechobee and other large shallow lakes, complex models that explicitly consider wind-wave energy,
hydrodynamics, and sediment resuspension, transport, and key biological processes are needed to accurately predict how lake
water TP will respond to different management options. 相似文献
124.
JAN E. JANEČKA LON I. GRASSMAN JR. RODNEY L. HONEYCUTT MICHAEL E. TEWES 《The Journal of wildlife management》2007,71(4):1357-1360
Abstract: We describe a method for rapidly amplifying whole genomes via a Phi29 DNA polymerase-mediated strand displacement reaction (SDR). Genomic amplification products derived from the SDR reaction resulted in high quantities of DNA suitable for polymerase chain reaction (PCR) amplification and sequencing of mitochondrial genomes. Control region sequences of DNA derived directly from PCR amplicons of extracted DNA were identical to those derived from PCR amplification of SDR genomic DNA. Effective SDR amplification and subsequent sequencing was successful across tissues sources ranging in age from 1 year to 19 years. Strand replacement reaction genomic amplification offers a means of obtaining large quantities of DNA from small amounts of tissue. 相似文献
125.
Havens Karl E. Ji Gaohua Beaver John R. Fulton Rolland S. Teacher Catherine E. 《Hydrobiologia》2019,829(1):43-59
Hydrobiologia - Analysis of an 18-year dataset from seven shallow lakes in Florida provides evidence of hydrologic factors controlling dynamics of cyanobacteria blooms. Depth was the most important... 相似文献
126.
The objective of the study was to examine salivary biomarker response to fluid consumption in exercising athletes. Exercise induces stress on the body and salivary alpha amylase (sAA) and salivary cortisol are useful biomarkers for activity in the sympathoadrenal medullary system and the hypothalamic pituitary adrenal axis which are involved in the stress response. Fifteen college students were given 150 ml and 500 ml of water on different days and blinded to fluid condition. The exercise protocol was identical for both fluid conditions using absolute exercise intensities ranging from moderate to high. Saliva was collected prior to exercise, post moderate and post high intensities and analyzed by Salimetrics assays. Exercise was significant for sAA with values different between pre-exercise (85 ± 10 U · ml−1) and high intensity (284 ± 30 U · ml−1) as well as between moderate intensity (204 ± 32 U · ml−1) and high intensity. There was no difference in sAA values between fluid conditions at either intensity. Exercise intensity and fluid condition were each significant for cortisol. Cortisol values were different between pre-exercise (0.30 ± 0.03 ug · dL−1) and high intensity (0.45 ± 0.05 ug · dL−1) as well as between moderate intensity (0.33 ± 0.04 ug · dL−1) and high intensity. Moderate exercise intensity cortisol was lower in the 500 ml condition (0.33 ± 0.03 ug · dL−1) compared with the 150 ml condition (0.38 ± 0.03 ug · dL−1). This altered physiological response due to fluid consumption could influence sport performance and should be considered. In addition, future sport and exercise studies should control for fluid consumption. 相似文献
127.
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129.
Gu Binhe; Havens Karl E.; Schelske Claire L.; Rosen Barry H. 《Journal of plankton research》1997,19(6):759-770
Uptake rates for ananonium, nitrate, urea and dinitrogen byphytoplankton in Lake Okeechobee ranged from 0.58 to 1.52 µmol11 h1 among four representative stations duringa short-term study period. Ammonium accounted for 53% of theuptake rates, followed by nitrate (19%), urea (16%) and dinitrogen(12%). Half-saturation constants for nitrogen (N) uptake rangedfrom 8.70 µmol 11 for ammonium, 2.07 iimol 11for urea and 2.21 µmol 11 for nitrate at Southstation. This study reveals spatially varying N uptake rates,particularly N fixation, within a large eutrophic lake. 相似文献
130.
红细胞在钙离子和离子载体A23187作用下的流变特性研究 总被引:1,自引:0,他引:1
用新激光衍射法研究了钙离子及离子载体A23187对红细胞流变特性的影响.用不同浓度的钙离子及离子载体A23187分别处理红细胞后,测量其取向指数和小变形指数.结果表明离子载体A23187较细胞外钙离子浓度对红细胞流变特性的影响更大.而且,最大取向指数和最大小变形指数随着钙离子及离子载体A23187浓度的增加而降低.离子载体A23187浓度增加导致红细胞变形能力明显降低. 相似文献