999 research outputs found
Ecological uncertainty influences vigilance as a marker of fear
We expand on the factors that may shape the predictability of risk and the potential impacts on the links between vigilance and fear, primarily in aquatic prey communities. Uncertainty in predation risks has been shown to induce increased levels of neophobia among prey. As a result of this phenotypically plastic response, prey are faced with risk assessment cues that may vary widely in their reliability. We argue that decomposing predictability may provide useful insights into the relationship between vigilance and fear
Ecological uncertainty influences vigilance as a marker of fear
We expand on the factors that may shape the predictability of risk and the potential impacts on the links between vigilance and fear, primarily in aquatic prey communities. Uncertainty in predation risks has been shown to induce increased levels of neophobia among prey. As a result of this phenotypically plastic response, prey are faced with risk assessment cues that may vary widely in their reliability. We argue that decomposing predictability may provide useful insights into the relationship between vigilance and fear
Experimental Line Parameters of the b^(1)ÎŁ^(+)_g â X^(3)ÎŁ^(-)_g Band of Oxygen Isotopologues at 760 nm Using Frequency-Stabilized Cavity Ring-Down Spectroscopy
Positions, intensities, self-broadened widths, and collisional narrowing coefficients of the oxygen isotopologues ^(16)O^(18)O, ^(16)O^(17)O, ^(17)O^(18)O, and ^(18)O^(18)O have been measured for the b^(1)ÎŁg + â X^(3)ÎŁg â (0,0) band using frequency-stabilized cavity ring-down spectroscopy. Line positions of 156 P-branch transitions were referenced against the hyperfine components of the ^(39)K D_1 (4s ^(2)S_(1/2) â 4p ^(2)P_(1/2)) and D_2 (4s ^(2)S_(1/2) â 4p ^(2)P_(3/2)) transitions, yielding precisions of ~0.00005 cm^(â1) and absolute accuracies of 0.00030 cm^(â1) or better. New excited b^(1)ÎŁg + state molecular constants are reported for all four isotopologues. The measured line intensities of the ^(16)O^(18)O isotopologue are within 2% of the values currently assumed in molecular databases. However, the line intensities of the ^(16)O^(17)O isotopologue show a systematic, J-dependent offset between our results and the databases. Self-broadening half-widths for the various isotopologues are internally consistent to within 2%. This is the first comprehensive study of the line intensities and shapes for the ^(17)O^(18)O or ^(18)O_2 isotopologues of the b^(1)ÎŁg + â X^(3)ÎŁg â (0,0) band of O_2. The ^(16)O_2, ^(16)O^(18)O, and ^(16)O^(17)O line parameters for the oxygen A-band have been extensively revised in the HITRAN 2008 database using results from the present study
Volume independence in large Nc QCD-like gauge theories
Volume independence in large \Nc gauge theories may be viewed as a
generalized orbifold equivalence. The reduction to zero volume (or Eguchi-Kawai
reduction) is a special case of this equivalence. So is temperature
independence in confining phases. In pure Yang-Mills theory, the failure of
volume independence for sufficiently small volumes (at weak coupling) due to
spontaneous breaking of center symmetry, together with its validity above a
critical size, nicely illustrate the symmetry realization conditions which are
both necessary and sufficient for large \Nc orbifold equivalence. The
existence of a minimal size below which volume independence fails also applies
to Yang-Mills theory with antisymmetric representation fermions [QCD(AS)].
However, in Yang-Mills theory with adjoint representation fermions [QCD(Adj)],
endowed with periodic boundary conditions, volume independence remains valid
down to arbitrarily small size. In sufficiently large volumes, QCD(Adj) and
QCD(AS) have a large \Nc ``orientifold'' equivalence, provided charge
conjugation symmetry is unbroken in the latter theory. Therefore, via a
combined orbifold-orientifold mapping, a well-defined large \Nc equivalence
exists between QCD(AS) in large, or infinite, volume and QCD(Adj) in
arbitrarily small volume. Since asymptotically free gauge theories, such as
QCD(Adj), are much easier to study (analytically or numerically) in small
volume, this equivalence should allow greater understanding of large \Nc QCD
in infinite volume.Comment: 32 pages, 4 figure
Efficient Parallel Statistical Model Checking of Biochemical Networks
We consider the problem of verifying stochastic models of biochemical
networks against behavioral properties expressed in temporal logic terms. Exact
probabilistic verification approaches such as, for example, CSL/PCTL model
checking, are undermined by a huge computational demand which rule them out for
most real case studies. Less demanding approaches, such as statistical model
checking, estimate the likelihood that a property is satisfied by sampling
executions out of the stochastic model. We propose a methodology for
efficiently estimating the likelihood that a LTL property P holds of a
stochastic model of a biochemical network. As with other statistical
verification techniques, the methodology we propose uses a stochastic
simulation algorithm for generating execution samples, however there are three
key aspects that improve the efficiency: first, the sample generation is driven
by on-the-fly verification of P which results in optimal overall simulation
time. Second, the confidence interval estimation for the probability of P to
hold is based on an efficient variant of the Wilson method which ensures a
faster convergence. Third, the whole methodology is designed according to a
parallel fashion and a prototype software tool has been implemented that
performs the sampling/verification process in parallel over an HPC
architecture
Book reviews
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45646/1/11199_2004_Article_BF00290970.pd
Evaluating annual severe coral bleaching risk for marine protected areas across Indonesia
Coral reefs face an uncertain future under global climate change, with thermal-induced bleaching increasing in frequency such that corals will soon experience annual severe bleaching (ASB). Marine Protected Areas (MPAs) are therefore becoming increasingly important as a conservation tool. Here we evaluate (i) Indonesiaâs coral reefsâ spatial variation in ASB, (ii) whether reefs projected to have a later onset of ASB (i.e. possible climate refugia) are protected within MPAs, and (iii) the ASB risk profiles for reefs related to MPAs receiving priority investments. Our results highlight considerable variability across Indonesiaâs reefs being at risk of ASB. The ASB risk before 2028 is greater for coral reefs protected by MPAs versus those outside MPA boundaries. The ASB risk before 2025 is greater for coral reefs protected by priority MPAs versus those protected by non-priority MPAs. Overall, our results show that only âŒ45% of the coral reef areas that are currently located within MPAs will likely act as thermal refugia (ASB > 2044). This is unsurprising given that the MPA network in Indonesia has been established over many decades, with most MPAs designated before suitable bleaching risk projections were available to inform MPA placement. Our results highlight the scope to further incorporate potential climate refugia for reefs into new MPA designations. This study also provides strategic information, which can support the development of Indonesiaâs long-term MPA and coral reef conservation strategy to effectively manage, mitigate, and adapt to the impacts of climate change on coral reefs
New Insights Into the Clinical and Molecular Spectrum of the Novel CYFIP2-Related Neurodevelopmental Disorder and Impairment of the WRC-Mediated Actin Dynamics
Purpose: A few de novo missense variants in the cytoplasmic FMRP-interacting protein 2 (CYFIP2) gene have recently been described as a novel cause of severe intellectual disability, seizures, and hypotonia in 18 individuals, with p.Arg87 substitutions in the majority. Methods: We assembled data from 19 newly identified and all 18 previously published individuals with CYFIP2 variants. By structural modeling and investigation of WAVE-regulatory complex (WRC)-mediated actin polymerization in six patient fibroblast lines we assessed the impact of CYFIP2 variants on the WRC. Results: Sixteen of 19 individuals harbor two previously described and 11 novel (likely) disease-associated missense variants. We report p.Asp724 as second mutational hotspot (4/19 cases). Genotypeâphenotype correlation confirms a consistently severe phenotype in p.Arg87 patients but a more variable phenotype in p.Asp724 and other substitutions. Three individuals with milder phenotypes carry putative loss-of-function variants, which remain of unclear pathogenicity. Structural modeling predicted missense variants to disturb interactions within the WRC or impair CYFIP2 stability. Consistent with its role in WRC-mediated actin polymerization we substantiate aberrant regulation of the actin cytoskeleton in patient fibroblasts. Conclusion: Our study expands the clinical and molecular spectrum of CYFIP2-related neurodevelopmental disorder and provides evidence for aberrant WRC-mediated actin dynamics as contributing cellular pathomechanism
Non-perturbative dynamics of hot non-Abelian gauge fields: beyond leading log approximation
Many aspects of high-temperature gauge theories, such as the electroweak
baryon number violation rate, color conductivity, and the hard gluon damping
rate, have previously been understood only at leading logarithmic order (that
is, neglecting effects suppressed only by an inverse logarithm of the gauge
coupling). We discuss how to systematically go beyond leading logarithmic order
in the analysis of physical quantities. Specifically, we extend to
next-to-leading-log order (NLLO) the simple leading-log effective theory due to
Bodeker that describes non-perturbative color physics in hot non-Abelian
plasmas. A suitable scaling analysis is used to show that no new operators
enter the effective theory at next-to-leading-log order. However, a NLLO
calculation of the color conductivity is required, and we report the resulting
value. Our NLLO result for the color conductivity can be trivially combined
with previous numerical work by G. Moore to yield a NLLO result for the hot
electroweak baryon number violation rate.Comment: 20 pages, 1 figur
Targeted Morphoproteomic Profiling of Ewing's Sarcoma Treated with Insulin-Like Growth Factor 1 Receptor (IGF1R) Inhibitors: Response/Resistance Signatures
Insulin-like growth factor 1 receptor (IGF1R) targeted therapies have resulted in responses in a small number of patients with advanced metastatic Ewing's sarcoma. We performed morphoproteomic profiling to better understand response/resistance mechanisms of Ewing's sarcoma to IGF1R inhibitor-based therapy.This pilot study assessed two patients with advanced Ewing's sarcoma treated with IGF1R antibody alone followed by combined IGF1R inhibitor plus mammalian target of rapamycin (mTOR) inhibitor treatment once resistance to single-agent IGF1R inhibitor developed. Immunohistochemical probes were applied to detect p-mTOR (Ser2448), p-Akt (Ser473), p-ERK1/2 (Thr202/Tyr204), nestin, and p-STAT3 (Tyr 705) in the original and recurrent tumor. The initial remarkable radiographic responses to IGF1R-antibody therapy was followed by resistance and then response to combined IGF1R plus mTOR inhibitor therapy in both patients, and then resistance to the combination regimen in one patient. In patient 1, upregulation of p-Akt and p-mTOR in the tumor that relapsed after initial response to IGF1R antibody might explain the resistance that developed, and the subsequent response to combined IGF1R plus mTOR inhibitor therapy. In patient 2, upregulation of mTOR was seen in the primary tumor, perhaps explaining the initial response to the IGF1R and mTOR inhibitor combination, while the resistant tumor that emerged showed activation of the ERK pathway as well.Morphoproteomic analysis revealed that the mTOR pathway was activated in these two patients with advanced Ewing's sarcoma who showed response to combined IGF1R and mTOR inhibition, and the ERK pathway in the patient in whom resistance to this combination emerged. Our pilot results suggests that morphoproteomic assessment of signaling pathway activation in Ewing's sarcoma merits further investigation as a guide to understanding response and resistance signatures
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