2,612 research outputs found
The status of shark and ray fishery resources in the Gulf of California: applied research to improve management and conservation
Seasonal surveys were conducted during 1998–1999 in Baja California, Baja California Sur, Sonora, and Sinaloa to determine the extent and activities of artisanal elasmobranch fisheries in the Gulf of California. One hundred and forty–seven fishing sites, or camps, were documented, the majority of which (n = 83) were located in Baja California Sur. Among camps with adequate fisheries information, the great majority (85.7%) targeted elasmobranchs during some part of the year. Most small, demersal sharks and rays were landed in mixed species fisheries that also targeted demersal teleosts, but large sharks were usually targeted in directed drift gillnet or, to a lesser extent, surface longline fisheries. Artisanal fishermen were highly opportunistic, and temporally switched targets depending on the local productivity of teleost, invertebrate, and elasmobranch fishery resources. Major fisheries for small sharks ( 1.5 m, “tiburón”) were minor components of artisanal elasmobranch fisheries in Sonora and Sinaloa, but were commonly targeted during summer and early autumn in Baja California and Baja California Sur. The pelagic thresher shark (Alopias pelagicus) and silky shark (Carcharhinus falciformis) were most commonly landed in Baja California, whereas a diverse assemblage of pelagic and large coastal sharks was noted among Baja California Sur landings. Rays dominated summer landings in Baja California and Sinaloa, when elevated catch rates of the shovelnose guitarfish (Rhinobatos productus, 13.2 individuals/vessel/trip) and golden cownose ray (Rhinoptera steindachneri, 11.1 individuals/vesse/trip) primarily supported the respective fisheries. The Sonoran artisanal elasmobranch fishery was the most expansive recorded during this study, and rays (especially R. productus) dominated spring and summer landings in this state. Seasonal catch rates of small demersal sharks and rays were considerably greater in Sonora than in other surveyed states. Many tiburón populations (e.g., C. leucas, C. limbatus, C. obscurus, Galeocerdo cuvier) have likely been overfished, possibly shifting effort towards coastal populations of cazón and rays. Management recommendations, including conducting demographic analyses using available life history data, determining and protecting nursery areas, and enacting seasonal closures in areas of elasmobranch aggregation (e.g., reproduction, feeding), are proposed. Without effective, enforceable management to sustain or rebuild targeted elasmobranch populations in the Gulf of California, collapse of many fisheries is a likely outcome. (PDF contains 243 pages
Adsorption and Vibrational Study of Folic Acid on Gold Nanopillar Structures Using Surface-enhanced Raman Scattering Spectroscopy
This paper presents a study of adsorption and vibrational features of folic acid, using surface-enhanced Raman scattering (SERS). A gold-capped silicon nanopillar (Au NP) with a height of 600 nm and a width of 120 nm was utilized to study the vibrational features of FA molecules adsorbed on the nanopillars within the high electromagnetic field areas. The adsorption behaviour of folic acid and the band assignment of the main vibrations together with the optimized geometry of folic acid and folic acid in the presence of a cluster of 10 gold atoms were assessed using the density functional theory (B3LYP(6-31G(d))) and the scalar relativistic effective core potential with a double-zeta basis set (LANL2DZ). The vibrations obtained from the solid-state folic acid and the folic acid on a gold cluster were in accordance with those observed experimentally. The analysis of the main vibrations indicated that the interaction of folic acid with the Au NP occurred primarily through the nitrogen atoms, from their pteridine ring. Finally, the obtained adsorption isotherm for folic acid was deduced from the analysis of the SERS spectra and it followed a negative cooperative binding model
Long-range correlations and patterns of recurrence in children and adults' attention to hierarchical displays
In order to make sense of a scene, a person must pay attention to several levels of nested order, ranging from the most differentiated details of the display to the integrated whole. In adults, research shows that the processes of integration and differentiation have the signature of self-organization. Does the same hold for children? The current study addresses this question with children between 6 and 9 years of age, using two tasks that require attention to hierarchical displays. A group of adults were tested as well, for control purposes. To get at the question of self-organization, reaction time data were submitted to a detrended fluctuation analysis and a recurrence quantification analysis. Hurst exponents shows a long-range correlations (1/f noise), and recurrence measures (percent determinism, maximum line, entropy, and trend), show a deterministic structure of variability being characteristic of self-organizing systems. Findings are discussed in terms of organism-environment coupling that gives rise to fluid attention to hierarchical displays
Walks on SPR Neighborhoods
A nearest-neighbor-interchange (NNI) walk is a sequence of unrooted
phylogenetic trees, T_0, T_1, T_2,... where each consecutive pair of trees
differ by a single NNI move. We give tight bounds on the length of the shortest
NNI-walks that visit all trees in an subtree-prune-and-regraft (SPR)
neighborhood of a given tree. For any unrooted, binary tree, T, on n leaves,
the shortest walk takes {\theta}(n^2) additional steps than the number of trees
in the SPR neighborhood. This answers Bryant's Second Combinatorial Conjecture
from the Phylogenetics Challenges List, the Isaac Newton Institute, 2011, and
the Penny Ante Problem List, 2009
Combustion Synthesis of Ca3(PO4)2 Net-Shape Surgical Implants
Self-propagating high-temperature combustion synthesis (SHS) is the basis of a method of making components of porous tricalcium phosphate [Ca3(PO4)2] and related compounds in net sizes and shapes for use as surgical implants that are compatible with bone. The SHS method offers advantages over prior methods of manufacturing Ca3(PO4)2-based surgical implants
Randomized clinical trial of the effects of screening and brief intervention for illicit drug use: the Life Shift/Shift Gears study.
BackgroundAlthough screening, brief intervention, and referral to treatment (SBIRT) has shown promise for alcohol use, relatively little is known about its effectiveness for adult illicit drug use. This randomized controlled trial assessed the effectiveness of the SBIRT approach for outcomes related to drug use among patients visiting trauma and emergency departments (EDs) at two large, urban hospitals.MethodsA total of 700 ED patients who admitted using illegal drugs in the past 30 days were recruited, consented, provided baseline measures of substance use and related problems measured with the Addiction Severity Index-Lite (ASI-Lite), and then randomized to the Life Shift SBIRT intervention or to an attention-placebo control group focusing on driving and traffic safety (Shift Gears). Both groups received a level of motivational intervention matched to their condition and risk level by trained paraprofessional health educators. Separate measurement technicians conducted face-to-face follow-ups at 6 months post-intervention and collected hair samples to confirm reports of abstinence from drug use. The primary outcome measure of the study was past 30-day drug abstinence at 6 months post-intervention, as self-reported on the ASI-Lite.ResultsOf 700 participants, 292 (42%) completed follow-up. There were no significant differences in self-reported abstinence (12.5% vs. 12.0% , p = 0.88) for Life Shift and Shift Gears groups, respectively. When results of hair analyses were applied, the abstinence rate was 7 percent for Life Shift and 2 percent for Shift Gears (p = .074). In an analysis in which results were imputed (n = 694), there was no significant difference in the ASI-Lite drug use composite scores (Life Shift +0.005 vs. Shift Gears +0.017, p = 0.12).ConclusionsIn this randomized controlled trial, there was no evidence of effectiveness of SBIRT on the primary drug use outcome.Trial registrationClinicalTrials.gov NCT01683227
Plasmablastic Lymphoma: A Systematic Review
Plasmablastic lymphoma (PBL) is a very aggressive variant of diffuse large B-cell lymphoma initially described in the oral cavity of HIV-infected individuals. PBL represents a diagnostic challenge given its characteristic morphology and lack of CD20 expression, and also a therapeutic challenge, with early responses to therapy, but with high relapse rates and poor prognosis. In recent years, our understanding and clinical experience with PBL has increased in both HIV-positive and -negative settings. However, given its rarity, most of the data available rely on case reports and case series. The main goal of this article is to systematically review the most recent advances in epidemiology; pathophysiology; clinical, pathologic, and molecular characteristics; therapy; and prognosis in patients with PBL. Specific covered topics include new pathological markers for diagnosis, its association with Epstein-Barr virus, and the need of more intensive therapies
On the Use of CYGNSS to Observe Convectively Driven Near-Surface Winds in Tropical Precipitation Systems
No abstract availabl
Detección electroquímica de peróxido de hidrógeno usando peroxidasa de pasto Guinea (Panicum maximum) inmovilizada sobre electrodos serigrafiados de puntos cuánticos
Electrochemical biosensors are analytical tools of fast and reliable response that have acquired interest in the last years due to the possibility of integrating biomolecules and electrodes made of nanometric materials. In this study, an electrochemical biosensor to detect hydrogen peroxide (H2O2) based on Guinea Grass peroxidase (GGP) immobilized on screen-printed quantum dots electrodes (SPQDE) was developed. GGP was partially purified from Guinea grass leaves having a specific activity of 602 U mg-1.Then, GGP was immobilized by physical adsorption on the surface on SPQDE and the electrochemical behavior was carried out through cyclic voltammetry and chronoamperometry techniques. GGP revealed a well-defined pair of redox signals at 17mV/-141mV corresponding to the redox process of the heme group (Fe2+/Fe3+) of peroxidases. The bioelectrocatalytic reduction of H2O2 has a redox potential of -645 mV vs Ag. This process was controlled by the diffusion of the species on the electrode surface using a scan rate range of 50-500 mV s. Chronoamperometry studies allow us the construction of calibration curves of reduction current vs H2O2 concentration for the determination of analytical parameters such as sensitivity, linear range and minimum detection level. The development of this amperometric biosensor becomes a preliminary step for the construction of a portable and rapid response device for the analysis of H2O2 in samples of environmental and biomedical interest.Os biossensores eletroquímicos são ferramentas analíticas de resposta rápida e confiável que adquiriram interesse especial nos últimos anos, graças à possibilidade de integrar biomoléculas com eletrodos feitos de materiais nanométricos. Neste trabalho, um biossensor eletroquímico foi desenvolvido para a detecção de peróxido de hidrogênio (H2O2) usando peroxidase do capim-da-Guiné (PPG) imobilizada em eletrodos serigráficos de pontos quânticos (ESPC) serigrafados. O PPG foi isolado e parcialmente purificado a partir de folhas de capim-da-Guiné com atividade específica de 602 U mg-1. Posteriormente, o PPG foi imobilizado na superfície do ESPC por adsorção física e estudo do comportamento eletroquímico foi realizado por voltametria cíclica e cronoamperometria. O PPG revelou um par bem definido de sinais redox em 17mV/-141mV correspondente ao processo redox do grupo heme (Fe2+/Fe3+) de peroxidases. A redução bioeletrocatalítica do H2O2 foi observada com um potencial redox de -645 mV vs. Ag. Esse processo foi controlado pela difusão das espécies na superfície do eletrodo em uma faixa de velocidade de varredura linear de 50-500 mV/s. A cronoamperometria permitiu a construção de curvas de calibração entre a corrente de redução e a concentração de H2O2 para a determinação de parâmetros analíticos como sensibilidade, faixa linear e nível mínimo de detecção. O desenvolvimento deste biossensor amperométrico torna-se uma etapa preliminar para a construção de um dispositivo portátil e de resposta rápida para a análise de H2O2 em amostras de interesse ambiental e biomédico.Los biosensores electroquímicos son herramientas analíticas de rápida y confiable respuesta que han adquirido especial interés en los últimos años gracias a la posibilidad de integrar biomoléculas con electrodos hechos a base de materiales nanométricos. En este trabajo se desarrolló un biosensor electroquímico para detección de peróxido de hidrógeno (H2O2) usando peroxidasa de pasto Guinea (PPG) inmovilizada sobre electrodos serigrafiados de puntos cuánticos (ESPC). La PPG fue aislada y parcialmente purificada a partir de hojas de pasto Guinea con una actividad específica de 602 Umg-1. Posteriormente, la PPG fue inmovilizada sobre la superficie del ESPC mediante adsorción física y el estudio del comportamiento electroquímico fue llevado a cabo mediante voltamperometría cíclica y cronoamperometría. La PPG reveló una pareja bien definida de señales redox a 17mV/-141mV correspondientes al proceso redox del grupo hemo (Fe2+/Fe3+) de las peroxidasas. La reducción bioelectrocatalítica del peróxido de hidrógeno se observó a un potencial redox de -645 mV vs Ag. Este proceso fue controlado por difusión de las especies en la superficie del electrodo en un rango de velocidad de barrido lineal de 50-500 mV/s. La cronoamperometría permitió la construcción de curvas de calibración entre la corriente de reducción y la concentración del H2O2 para la determinación de parámetros analíticos como sensibilidad, rango lineal y nivel mínimo de detección. El desarrollo de este biosensor amperométrico se convierte en un paso preliminar para la construcción de un dispositivo portátil y de respuesta rápida para el análisis de H2O2 en muestras de interés ambiental y biomédico
Multivariate stabilizing sexual selection and the evolution of male and female genital morphology in the red flour beetle
Male genitals are highly divergent in animals with internal fertilization. Most studies attempting to explain this diversity have focused on testing the major hypotheses of genital evolution (the lock-and-key, pleiotropy, and sexual selection hypotheses), and quantifying the form of selection targeting male genitals has played an important role in this endeavor. However, we currently know far less about selection targeting female genitals or how male and female genitals interact during mating. Here, we use formal selection analysis to show that genital size and shape is subject to strong multivariate stabilizing sexual selection in both sexes of the red flour beetle, Tribolium castaneum. Moreover, we show significant sexual selection on the covariance between the sexes for specific aspects of genital shape suggesting that male and female genitalia also interact to determine the successful transfer of a spermatophore during mating. Our work therefore highlights the important role that both male and female genital morphologies play in determining mating success and that these effects can occur independently, as well as through their interaction. Moreover, it cautions against the overly simplistic view that the sexual selection targeting genital morphology will always be directional in form and restricted primarily to males
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