3,352 research outputs found
Ex. 280-US-416
A report on the movement of Lost River and shortnose suckers through the Sprague River ladder at the Chiloquin Dam, Spring 2000
Ex. 280-US-416
A report on the movement of Lost River and shortnose suckers through the Sprague River ladder at the Chiloquin Dam, Spring 2000
Quantifying wet scavenging processes in aircraft observations of nitric acid and cloud condensation nuclei
Condition-dependence of Defensive Tail Displays in Common Garter Snakes (Thamnophis sirtalis)
Individual snakes can exhibit a diversity of antipredator responses including crypsis, flight, and a variety of stereotyped behavioral reactions to predators at close range. Among these responses are behavioral differences in the movement (e.g., waving or wiggling) of a conspicuous tail by an otherwise cryptically colored snake. Defensive tail displays may disorient a predator, divert attack to the tail, act as a warning signal, or serve no function at all. The use of tail displays in snakes may also depend on current physiological investment into color production and body size, which can affect locomotor ability to escape predators. The purpose of this study was to determine if variation in tail color is related to the defensive tail behavior exhibited in Common Garter Snakes (Thamnophis sirtalis) when subject to a sudden tactile stimulus. We also analyzed potential relationships between tail coloration, mass, and circulating concentrations of testosterone, to determine if conspicuous tail morphology is condition-dependent. Here, relative tail orange coverage is significantly related to defensive tail behavior and also yields significant negative correlations with mass and testosterone concentrations. This suggests conspicuous tail displays in T. sirtalis to be a size-dependent response to predation, as mediated by testosterone. The prevalence of this defensive behavior in relatively smaller snakes may function as a diversion of attack to the tail while larger snakes instead exhibit greater locomotor capacity to escape predation
Investigating the Relationship Between Corticosterone and Glucose in a Reptile
The glucocorticoid hormone corticosterone (CORT) has classically been used in ecophysiological studies as a proxy for stress and energy mobilization, but rarely are CORT and the energy metabolites themselves concurrently measured. To examine CORT\u27s role in mobilizing glucose in a wild reptile, we conducted two studies. The first study measured natural baseline and stress-induced blood-borne CORT and glucose levels in snakes during spring emergence and again when snakes return to the denning sites in autumn. The second study manipulated the hypothalamic–pituitary–adrenal (HPA) axis in male snakes in the autumn by taking a baseline blood sample, then subjecting individuals to one of five treatments (no injection, saline, CORT, adrenocorticotropin hormone and metyrapone). Subsequent samples were taken at 30 and 60 min. In both studies, we found that glucose levels do increase with acute stress, but that the relationship was not directly related to CORT elevation. In the second study, we found that none of the HPA axis manipulations directly affected blood glucose levels, further indicating that CORT may play a complex but not direct role in glucose mobilization in snakes. This study highlights the need for testing mechanisms in wild organisms by combining in situ observations with manipulative studies
Fractional Operators, Dirichlet Averages, and Splines
Fractional differential and integral operators, Dirichlet averages, and
splines of complex order are three seemingly distinct mathematical subject
areas addressing different questions and employing different methodologies. It
is the purpose of this paper to show that there are deep and interesting
relationships between these three areas. First a brief introduction to
fractional differential and integral operators defined on Lizorkin spaces is
presented and some of their main properties exhibited. This particular approach
has the advantage that several definitions of fractional derivatives and
integrals coincide. We then introduce Dirichlet averages and extend their
definition to an infinite-dimensional setting that is needed to exhibit the
relationships to splines of complex order. Finally, we focus on splines of
complex order and, in particular, on cardinal B-splines of complex order. The
fundamental connections to fractional derivatives and integrals as well as
Dirichlet averages are presented
Transition from non-motile behaviour to directed migration during early PGC development in zebrafish
Replication of linkage of familial hypobetalipoproteinemia to chromosome 3p in six kindreds
Familial hypobetalipoproteinemia (FHBL) is a genetically heterogeneous condition characterized by very low apolipoprotein B (apoB) concentrations in plasma and/or low levels of LDL-cholesterol (LDL-C) with a propensity to developing fatty liver. In a minority of cases, truncation-specifying mutations of the apoB gene (APOB) are etiologic, but the genetic basis of most cases is unknown. We previously reported linkage of FHBL to a 10 cM region on 3p21.1-22 in one kindred. The objectives of the current study were to identify other FHBL families with linkage to 3p and to narrow the FHBL susceptibility region on 3p. Six additional FHBL kindreds unlinked to the APOB region on chromosome 2 were genotyped with polymorphic markers spanning a region of approximately 13 cM on chromosome 3. Quantitative linkage analyses indicated that the FHBL in these families was linked to 3p21.1-22. Haplotype analysis identified several meiotic crossover events, allowing us to narrow the critical region from 10 cM to 2.0 cM, between markers D3S2407 and D3S1767
Bromine measurements in ozone depleted air over the Arctic Ocean
In situ measurements of ozone, photochemically active bromine compounds, and other trace gases over the Arctic Ocean in April 2008 are used to examine the chemistry and geographical extent of ozone depletion in the arctic marine boundary layer (MBL). Data were obtained from the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) study and the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) study. Fast (1 s) and sensitive (detection limits at the low pptv level) measurements of BrCl and BrO were obtained from three different chemical ionization mass spectrometer (CIMS) instruments, and soluble bromide was measured with a mist chamber. The CIMS instruments also detected Br2. Subsequent laboratory studies showed that HOBr rapidly converts to Br2 on the Teflon instrument inlets. This detected Br2 is identified as active bromine and represents a lower limit of the sum HOBr + Br2. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted. Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2 pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere
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