5,124 research outputs found
Mutual mate choice in the potbellied seahorse (Hippocampus abdominalis)
Models of sexual selection often assume dichotomous sex roles, with one sex competing for access to mates, while the other sex is choosy. However, it is well known that mating decisions are realized by integrating information across multiple traits, the relative importance of which may be sex specific. While a large body of work has investigated the influence of sexual signals on mating behavior, such traits have typically been studied in isolation, oversimplifying the multimodal communication associated with natural mating behavior. We investigated the impact of 2 key traits (Major Histocompatibility Class II beta-chain [MHIIb] olfactory cues and body size) on mate choice decisions in the potbellied seahorse (Hippocampus abdominalis), a species considered to have female competition and male choice. We used a hierarchical experimental design (1. olfactory cues only, 2. olfactory and visual cues, and 3. free interaction) to investigate behavioral preferences and mating success of female and male seahorses under increasing levels of multimodal stimulation. Our data show that female seahorses prefer and mate with MHIIb-dissimilar males, while male seahorses mate randomly with respect to this trait. Conversely, males prefer and mate with large females, while females show no size-based mating preference. The multimodal integration of sex-specific mate preferences in mating behavior of the potbellied seahorse suggests the existence of mutual mate choice in this species. The results presented here suggest that more comprehensive studies of mating behavior, considering both female and male preferences for multiple traits, may lead to a more nuanced understanding of how sexual selection operates in natural population
A total variation-undecimated wavelet approach to chest radiograph image enhancement
Most often medical images such as X-Rays have a low dynamic range and many of their targeted features are difficult to identify. Intensity transformations that improve image quality usually rely onwavelet denoising and enhancement typically use the technique of thresholding to obtain better quality medical images. A disadvantage of wavelet thresholding is that even though it adequately removes noise in an image, it introduces unwanted artifacts into the image near discontinuities. We utilize a total variation method and an undecimated wavelet image enhancing algorithm for improving the image quality of chest radiographs. Our approach achieves a high level chest radiograph image deniosing in lung nodules detection while preserving the important features. Moreover, our method results in a high image sensitivity that reduces the average number of false positives on a test set of medical data
Seahorse Brood Pouch Transcriptome Reveals Common Genes Associated with Vertebrate Pregnancy
Viviparity (live birth) has evolved more than 150 times in vertebrates, and represents an excellent model system for studying the evolution of complex traits. There are at least 23 independent origins of viviparity in fishes, with syngnathid fishes (seahorses and pipefish) unique in exhibiting male pregnancy. Male seahorses and pipefish have evolved specialized brooding pouches that provide protection, gas exchange, osmoregulation, and limited nutrient provisioning to developing embryos. Pouch structures differ widely across the Syngnathidae, offering an ideal opportunity to study the evolution of reproductive complexity. However, the physiological and genetic changes facilitating male pregnancy are largely unknown. We used transcriptome profiling to examine pouch gene expression at successive gestational stages in a syngnathid with the most complex brood pouch morphology, the seahorse Hippocampus abdominalis. Using a unique time-calibrated RNA-seq data set including brood pouch at key stages of embryonic development, we identified transcriptional changes associated with brood pouch remodeling, nutrient and waste transport, gas exchange, osmoregulation, and immunological protection of developing embryos at conception, development and parturition. Key seahorse transcripts share homology with genes of reproductive function in pregnant mammals, reptiles, and other live-bearing fish, suggesting a common toolkit of genes regulating pregnancy in divergent evolutionary lineage
The paradox of retained genetic diversity of Hippocampus guttulatus in the face of demographic decline
Genetic diversity is the raw foundation for evolutionary potential. When genetic diversity is significantly reduced, the risk of extinction is heightened considerably. The long-snouted seahorse (Hippocampus guttulatus) is one of two seahorse species occurring in the North-East Atlantic. The population living in the Ria Formosa (South Portugal) declined dramatically between 2001 and 2008, prompting fears of greatly reduced genetic diversity and reduced effective population size, hallmarks of a genetic bottleneck. This study tests these hypotheses using samples from eight microsatellite loci taken from 2001 and 2013, on either side of the 2008 decline. The data suggest that the population has not lost its genetic diversity, and a genetic bottleneck was not detectable. However, overall relatedness increased between 2001 to 2013, leading to questions of future inbreeding. The effective population size has seemingly increased close to the threshold necessary for the population to retain its evolutionary potential, but whether these results have been affected by sample size is not clear. Several explanations are discussed for these unexpected results, such as gene flow, local decline due to dispersal to other areas of the Ria Formosa, and the potential that the duration of the demographic decline too short to record changes in the genetic diversity. Given the results presented here and recent evidence of a second population decline, the precise estimation of both gene flow and effective population size via more extensive genetic screening will be critical to effective population management.16-02-01-FMP-54, MAR-01.04.02-FEAMP-0029, UID/Multi/04326/2020info:eu-repo/semantics/publishedVersio
A Patient-Centered Description of Severe Asthma:Patient Understanding Leading to Assessment for a Severe Asthma Referral (PULSAR)
BACKGROUND: Although severe asthma can be life-threatening, many patients are unaware they have this condition. OBJECTIVES: Patient Understanding Leading to Assessment for a Severe Asthma Referral (PULSAR) is a novel, multidisciplinary working group aiming to develop and disseminate a global, patient-centered description of severe asthma to improve patient understanding of severe asthma and effect a change in patient behavior whereby patients are encouraged to visit their healthcare professional, when appropriate. METHODS: Current definitions from patient organization websites, asthma guidelines, and medication information for key asthma drugs were assessed and informed a multidisciplinary working group, convened to identify common concepts and terminology used to define severe asthma. A patient-centered description of severe asthma and patient checklist were drafted based on working-group discussions and reviewed by an external behavioral scientist for patient understanding and relevance. These were tested using an online US/Canadian survey. RESULTS: The patient-centered description of severe asthma and patient checklist were reviewed and re-drafted by the authors. The text was simplified following the behavioral-scientist review. The survey (n = 153) included 105 patients with severe asthma. Of those with severe asthma, 92.2% of patients reported that the description was consistent with their experiences of severe asthma and 92.6% of patients reported that the PULSAR initiative would encourage them to visit their healthcare provider. CONCLUSION: A patient-centered description of severe asthma has been developed and tested using patients with severe asthma; this description will allow patients to assess whether they might have severe asthma and prompt them to visit their healthcare provider, if appropriate
General Algorithm For Improved Lattice Actions on Parallel Computing Architectures
Quantum field theories underlie all of our understanding of the fundamental
forces of nature. The are relatively few first principles approaches to the
study of quantum field theories [such as quantum chromodynamics (QCD) relevant
to the strong interaction] away from the perturbative (i.e., weak-coupling)
regime. Currently the most common method is the use of Monte Carlo methods on a
hypercubic space-time lattice. These methods consume enormous computing power
for large lattices and it is essential that increasingly efficient algorithms
be developed to perform standard tasks in these lattice calculations. Here we
present a general algorithm for QCD that allows one to put any planar improved
gluonic lattice action onto a parallel computing architecture. High performance
masks for specific actions (including non-planar actions) are also presented.
These algorithms have been successfully employed by us in a variety of lattice
QCD calculations using improved lattice actions on a 128 node Thinking Machines
CM-5.
{\underline{Keywords}}: quantum field theory; quantum chromodynamics;
improved actions; parallel computing algorithms
Radiation modeling in the Earth and Mars atmospheres using LRO/CRaTER with the EMMREM Module
Abstract We expand upon the efforts of Joyce et al. (2013), who computed the modulation potential at the Moon using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft along with data products from the Earth-Moon-Mars Radiation Environment Module (EMMREM). Using the computed modulation potential, we calculate galactic cosmic ray (GCR) dose and dose equivalent rates in the Earth and Mars atmospheres for various altitudes over the course of the LRO mission. While we cannot validate these predictions by directly comparable measurement, we find that our results conform to expectations and are in good agreement with the nearest available measurements and therefore may be used as reasonable estimates for use in efforts in risk assessment in the planning of future space missions as well as in the study of GCRs. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other solar energetic particles measurements) is an online system designed to provide the scientific community with a comprehensive resource on the radiation environments of the inner heliosphere. The data products shown here will be incorporated into PREDICCS in order to further this effort and daily updates will be made available on the PREDICCS website (http://prediccs.sr.unh.edu). Key Points We model GCR dose and dose equivalent rates in Earth and Mars atmospheres Dose rates are in reasonable agreement with nearby measurements Data products will soon be made available on PREDICCS website
Is there evidence for export-led adoption of ISO 14001? A review of the literature using meta-regression
Does the export orientation of a firm affect the likelihood that it adopts an environmental management certification? We use meta-regression methods to analyze systematically the corpus of published research on export-led adoption of the largest and most prominent certification, ISO 14001. We show that the explanatory variables authors choose to include in their models reflect the tenets of stakeholder and institutional theories. We also find that the literature suffers from substantial publication bias but that, once this is accounted for appropriately, a genuine effect remains. The evidence from 20 years of published studies taken as a whole is that export does incentivize the adoption of the standard as often hypothesized by proponents of voluntary approaches and self-regulation
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