3,572 research outputs found
Age-related association of venom gene expression and diet of predatory gastropods
Abstract
Background
Venomous organisms serve as wonderful systems to study the evolution and expression of genes that are directly associated with prey capture. To evaluate the relationship between venom gene expression and prey utilization, we examined these features among individuals of different ages of the venomous, worm-eating marine snail Conus ebraeus. We determined expression levels of six genes that encode venom components, used a DNA-based approach to evaluate the identity of prey items, and compared patterns of venom gene expression and dietary specialization.
Results
C. ebraeus exhibits two major shifts in diet with age—an initial transition from a relatively broad dietary breadth to a narrower one and then a return to a broader diet. Venom gene expression patterns also change with growth. All six venom genes are up-regulated in small individuals, down-regulated in medium-sized individuals, and then either up-regulated or continued to be down-regulated in members of the largest size class. Venom gene expression is not significantly different among individuals consuming different types of prey, but instead is coupled and slightly delayed with shifts in prey diversity.
Conclusion
These results imply that changes in gene expression contribute to intraspecific variation of venom composition and that gene expression patterns respond to changes in the diversity of food resources during different growth stages.http://deepblue.lib.umich.edu/bitstream/2027.42/116871/1/12862_2016_Article_592.pd
Risk in Time: The Intertwined Nature of Risk Taking and Time Discounting
Standard economic models view risk taking and time discounting as two independent dimensions of decision making. However, mounting experimental evidence demonstrates striking parallels in patterns of risk taking and time discounting behavior and systematic interaction effects, which suggests that there may be common underlying forces driving these interactions. Here, we show that the inherent uncertainty associated with future prospects together with individuals’ proneness to probability weighting generates a unifying framework for explaining a large number of puzzling behavioral findings: delay-dependent risk tolerance, aversion to sequential resolution of uncertainty, preferences for the timing of the resolution of uncertainty, the differential discounting of risky and certain outcomes, hyperbolic discounting, subadditive discounting, and the order dependence of prospect valuation. Furthermore, all these phenomena can be accommodated by the same set of preference parameter values and plausible levels of inherent uncertainty
CSU data set of the FIRE marine stratocumulus IFO, The
August 1988.Includes bibliographical references.This research was funded by NASA under grant NAG 1-554 and by ONR under grant N00014-87-K-0228/P00001
CSU tethered balloon data set of the FIRE marine stratocumulus IFO, The
November, 1988.Includes bibliographical references.Funding agencies: National Aeronautics and Space Administration, Office of Naval Research. This research was funded by ONR under grant N00014-87-K-0228/P00001 and by NASA under grant NAG 1-554
Ecological Release and Venom Evolution of a Predatory Marine Snail at Easter Island
BACKGROUND:Ecological release is coupled with adaptive radiation and ecological diversification yet little is known about the molecular basis of phenotypic changes associated with this phenomenon. The venomous, predatory marine gastropod Conus miliaris has undergone ecological release and exhibits increased dietary breadth at Easter Island. METHODOLOGY/PRINCIPAL FINDINGS:We examined the extent of genetic differentiation of two genes expressed in the venom of C. miliaris among samples from Easter Island, American Samoa and Guam. The population from Easter Island exhibits unique frequencies of alleles that encode distinct peptides at both loci. Levels of divergence at these loci exceed observed levels of divergence observed at a mitochondrial gene region at Easter Island. CONCLUSIONS/SIGNIFICANCE:Patterns of genetic variation at two genes expressed in the venom of this C. miliaris suggest that selection has operated at these genes and contributed to the divergence of venom composition at Easter Island. These results show that ecological release is associated with strong selection pressures that promote the evolution of new phenotypes
Dark Matter attempts for CoGeNT and DAMA
Recently, the CoGeNT collaboration presented a positive signal for an annual
modulation in their data set. In light of the long standing annual modulation
signal in DAMA/LIBRA, we analyze the compatibility of both of these signal
within the hypothesis of dark matter (DM) scattering on nuclei, taking into
account existing experimental constraints. We consider the cases of elastic and
inelastic scattering with either spin-dependent or spin-independent coupling to
nucleons. We allow for isospin violating interactions as well as for light
mediators. We find that there is some tension between the size of the
modulation signal and the time-integrated event excess in CoGeNT, making it
difficult to explain both simultaneously. Moreover, within the wide range of DM
interaction models considered, we do not find a simultaneous explanation of
CoGeNT and DAMA/LIBRA compatible with constraints from other experiments.
However, in certain cases part of the data can be made consistent. For example,
the modulation signal from CoGeNT becomes consistent with the total rate and
with limits from other DM searches at 90% CL (but not with the DAMA/LIBRA
signal) if DM scattering is inelastic spin-independent with just the right
couplings to protons and neutrons to reduce the scattering rate on xenon.
Conversely the DAMA/LIBRA signal (but not CoGeNT) can be explained by
spin-dependent inelastic DM scattering.Comment: 20 pages, 9 figure
Finding the event structure of neuronal spike trains
Contains fulltext :
91821.pdf (publisher's version ) (Closed access
A Review of Controlling Motivational Strategies from a Self-Determination Theory Perspective: Implications for Sports Coaches
The aim of this paper is to present a preliminary taxonomy of six controlling strategies, primarily based on the parental and educational literatures, which we believe are employed by coaches in sport contexts. Research in the sport and physical education literature has primarily focused on coaches’ autonomysupportive behaviours. Surprisingly, there has been very little research on the use of controlling strategies. A brief overview of the research which delineates each proposed strategy is presented, as are examples of the potential manifestation of the behaviours associated with each strategy in the context of sports coaching. In line with self-determination theory (Deci & Ryan, 1985; Ryan & Deci, 2002), we propose that coach behaviours employed to pressure or control athletes have the potential to thwart athletes’ feelings of autonomy, competence,and relatedness, which, in turn, undermine athletes’ self-determined motivation and contribute to the development of controlled motives. When athletes feel pressured to behave in a certain way, a variety of negative consequences are expected to ensue which are to the detriment of the athletes’ well-being. The purpose of this paper is to raise awareness and interest in the darker side of sport participation and to offer suggestions for future research in this area
Genomic Resources Notes Accepted 1 August 2014–30 September 2014
This article documents the public availability of (i) transcriptome sequence data, assembly and annotation, and single nucleotide polymorphisms ( SNP s) for the cone snail Conus miliaris ; (ii) a set of SNP markers for two biotypes from the Culex pipiens mosquito complex; (iii) transcriptome sequence data, assembly and annotation for the mountain fly Drosophila nigrosparsa ; (iv) transcriptome sequence data, assembly and annotation and SNP s for the Neotropical toads Rhinella marina and R. schneideri ; and (v) partial genomic sequence assembly and annotation for 35 spiny lizard species (Genus Sceloporus ).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110107/1/men12340-sup-0004-AppendixS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110107/2/men12340-sup-0003-AppendixS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110107/3/men12340-sup-0002-AppendixS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110107/4/men12340-sup-0005-AppendixS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110107/5/men12340.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/110107/6/men12340-sup-0001-AppendixS1.pd
Circulation and intrusions northeast of Taiwan : chasing and predicting uncertainty in the cold dome
Author Posting. © The Oceanography Society, 2011. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 24 no. 4 (2011): 110–121, doi:10.5670/oceanog.2011.99.An important element of present oceanographic research is the assessment and quantification of uncertainty. These studies are challenging in the coastal ocean due to the wide variety of physical processes occurring on a broad range of spatial and temporal scales. In order to assess new methods for quantifying and predicting uncertainty, a joint Taiwan-US field program was undertaken in August/September 2009 to compare model forecasts of uncertainties in ocean circulation and acoustic propagation, with high-resolution in situ observations. The geographical setting was the continental shelf and slope northeast of Taiwan, where a feature called the "cold dome" frequently forms. Even though it is hypothesized that Kuroshio subsurface intrusions are the water sources for the cold dome, the dome's dynamics are highly uncertain, involving multiple scales and many interacting ocean features. During the experiment, a combination of near-surface and profiling drifters, broad-scale and high-resolution hydrography, mooring arrays, remote sensing, and regional ocean model forecasts of fields and uncertainties were used to assess mean fields and uncertainties in the region. River runoff from Typhoon Morakot, which hit Taiwan August 7–8, 2009, strongly affected shelf stratification. In addition to the river runoff, a cold cyclonic eddy advected into the region north of the Kuroshio, resulting in a cold dome formation event. Uncertainty forecasts were successfully employed to guide the hydrographic sampling plans. Measurements and forecasts also shed light on the evolution of cold dome waters, including the frequency of eddy shedding to the north-northeast, and interactions with the Kuroshio and tides. For the first time in such a complex region, comparisons between uncertainty forecasts and the model skill at measurement locations validated uncertainty forecasts. To complement the real-time model simulations, historical simulations with another model show that large Kuroshio intrusions were associated with low sea surface height anomalies east of Taiwan, suggesting that there may be some degree of predictability for Kuroshio intrusions.We thank the National Science Council
of Taiwan as well as the Office of
Naval Research for generous support
of this effort
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