372 research outputs found
Environmental drivers of diurnal visits by transient predatory fishes to Caribbean patch reefs
Video cameras recorded the diurnal visitation rates of transient (large home range) piscivorous fishes to coral patch reefs in The Bahamas and identified 11 species. Visits by bar jack Caranx ruber, mutton snapper Lutjanus analis, yellowtail snapper Ocyurus chrysurus, barracuda Sphyraena barracuda and cero Scomberomorus regalis were sufficiently frequent to correlate with a range of biophysical factors. Patch-reef visitation rates and fish abundances varied with distance from shore and all species except S. regalis were seen more frequently inshore. This pattern is likely to be caused by factors including close proximity to additional foraging areas in mangroves and on fore-reefs and higher abundances close to inshore nursery habitats. Visitation rates and abundances of C. ruber, L. analis, O. chrysurus and S. regalis also varied seasonally (spring v. winter), possibly as fishes responded to temperature changes or undertook spawning migrations. The abundance of each transient predator species on the patch reefs generally exhibited limited diurnal variability, but L. analis was seen more frequently towards dusk. This study demonstrates that the distribution of transient predators is correlated spatially and temporally with a range of factors, even within a single lagoon, and these drivers are species specific. Transient predators are considered an important source of mortality shaping reef-fish assemblages and their abundance, in combination with the biomass of resident predators, was negatively correlated with the density of prey fishes. Furthermore, transient predators are often targeted by fishers and understanding how they utilize seascapes is critical for protecting them within reserves
Prevalência de Doença Carotídea na Patologia Cérebro-Vascular Isquémica. O Papel do Eco-Doppler
BACKGROUND: Atherosclerotic carotid disease represents approximately 20% of the causes of ischemic stroke. Effective treatment options, such as endovascular or surgical revascularization procedures, are available. Doppler Ultrasound (DUS) is a non-invasive, inexpensive, routine exam used to evaluate the presence of internal carotid artery (ICA) stenosis. We retrospectively analysed the prevalence of severe atherosclerotic carotid disease in a population of patients with acute ischemic stroke/transitory ischemic attacks (TIAs), and the role of DUS in the detection of ICA stenosis and treatment decisions in these patients.
METHODS: A total of 318 patients with ischemic stroke or TIAs was admitted to our stroke unit, and 260 patients were studied by DUS. ICA stenosis was evaluated by DUS according to peak systolic velocity. All DUS exams were performed by the same operator. ICA stenosis was further assessed in 43 patients by digital subtraction angiography (DSA) using NASCET criteria.
RESULTS: Of the total 318 patients, 260 (82%) had DUS evaluation. Of the total 520 ICAs studied by DUS, degrees of ICA stenosis were: 0-29% n= 438 (84%); 30-49% n= 8 (2%); 50-69% n= 27 (5%); 70-89% n= 15 (3%); 90-99% n= 20 (4%); oclusão n= 14 (2%). Of the total 260 patients studied, 43 (16.5%) underwent DSA. Sensibility and specificity of DUS in the diagnosis of carotid stenosis over 70% were, respectively, 91% e 84%. Of the total 31 patients with significant carotid stenosis (70-99%), 23 (74%) underwent subsequent carotid revascularization procedures.
DISCUSSION: DUS is an important screening test in our stroke unit, justifying its use as a routine exam for all patients with ischemic stroke/TIAs. Moreover, our results show the relevance of severe carotid disease in a population with acute ischemic stroke/TIAs (16.5%), with a total of 9% of patients being submitted to carotid revascularization procedures
Socioeconomic and demographic factors associated with failure in Helicobacter pylori eradication using the standard triple therapy
Aim: To evaluate the influence of socioeconomic and demographic factors on the eradication rate of H. pylori, using standard triple therapy Background: the efficacy of the standard triple therapy (STT) for H. pylori eradication has decreased with the rise of antibiotic resistance. Other factors could influence the eradication failure, although available results are conflicting. Methods: Retrospective study, including adults with H. pylori infection treated de novo with STT (proton pump inhibitor, amoxicillin and clarithromycin). Eradication success was assessed by 13C-urea breath test. Demographic and socioeconomics variables were evaluated and correlated with eradication treatment outcome. The confounder variables were controlled by logistic regression analysis. Results: Out of 902 patients with H. pylori diagnosis, 693 met inclusion criteria (average age 53 years; females 55.2%). Nonsignificant differences were observed in relation to economics income between rural and urban areas (p=0.316). The eradication rate of H. pylori was 71.1%: male 78.9% vs female 65.9%, urban area 73.4% vs rural area 64.1%. With reference to age, income and nationality, the eradication rates were similar in all groups. According to logistic regression analysis, females had almost twice more likelihood of eradication failure in relation to males (OR 1.92; 95%CI: 1.38-2.72); and rural residents had OR 1.55 (95%CI: 1.03- 2.33) for having eradication failure in contrast with urban population. Conclusion: Female gender and rural residence are factors associated with H. Pylori eradication failure with standard triple therapy
Photosensitivity Color-Center Model for Ge-Doped Silica Preforms
A new photosensitivity physical model for Ge-doped silica preforms based on
color-center photoreactions is presented. Simulation results are in close agreement with
experimental results obtained by several condensed matter physics research groups working
in this field, suggesting that the photoreactions of this model may, indeed, describe the
physical processes involved in Ge-doped silica preform photosensitivity. The proposed
photosensitivity model is defined by two differential equations that describe the temporal
evolution of a set of color-center concentrations. The first is a modification of a very fast
reversible reaction previously proposed by Fujimaki et al., where the reaction precursor has
a different chemical structure (it is a neutral oxygen divacancy NODV unrelated to the
previously proposed germanium lone pair center GLPC). The chemical structure of this
precursor defect explains the generation of nonintrinsic neutral oxygen monovacancy
ðNOMVÞ color centers. These centers are transformed into GeE0 defects by means of a
second nonlinear reaction. This justifies the slow increase in the absorption peak experimentally
measured at 6.3 eV, which had no satisfactory explanation.Ministerio de Ciencia y Tecnología TIC2001-2969-C03-0
Unraveling the Prevalence of Antibiotic Resistance in Stenotrophomonas maltophilia: Insights into an Emerging Nosocomial Pathogen
Introduction: stenotrophomonas maltophilia is a clinically relevant opportunistic and nosocomial pathogen with increasing concerns regarding antibiotic resistance. Accurate diagnosis and identification are crucial for effective treatment, and misidentification can occur, thereby emphasizing the need for appropriate laboratory testing and surveillance. This review aimed to evaluate the epidemiology, pathogenesis, diagnosis, treatment, and antimicrobial resistance of Stenotrophomonas spp. Materials and Methods. A systematic literature review was conducted using the PubMed Central Database. Inclusion criteria included studies published in open-access scientific journals within the last five years, reporting information on Stenotrophomonas spp. epidemiology, pathogenesis, diagnosis, treatment, and/or antimicrobial resistance. The synthesis of the results involved a narrative synthesis of the findings from the included studies. Results. A total of 25 articles met the inclusion criteria and provided valuable insights into Stenotrophomonas spp. infections. The distribution of reported cases by country, sample type, and antimicrobial resistance patterns was summarized. The prevalence of resistance to various antibiotics was also assessed, highlighting the need for continuous surveillance. Conclusion. This analysis revealed the presence of antimicrobial resistance in Stenotrophomonas spp., particularly in S. maltophilia. The high prevalence of antibiotic resistance underscores the importance of ongoing surveillance and control measures to combat antibiotic resistance. The diverse distribution of S. maltophilia across different sample types emphasizes the need for accurate diagnosis and identification. Addressing antimicrobial resistance in Stenotrophomonas spp. is essential for global public health
Recomendações técnicas para a reprodução do tambaqui.
Das espécies nativas brasileiras, o tambaqui (Colossoma macropomum) é a mais produzida em cativeiro. Quase a totalidade da produção desse animal puro ocorre nos estados da região Norte do Brasil, com destaque para Rondônia. No Mato Grosso, existe grande produção do híbrido tambacu (tambaqui x pacu-caranha, Piaractus mesopotamicus). Isso se deve à popularidade do pacu-caranha na bacia do rio Paraguai e do repasse de tecnologia, no início dos anos 1980, do Centro Nacional de Pesquisa e Conservação de Peixes Continentais (Cepta), que recomendava a produção do híbrido com o objetivo de explorar o potencial de crescimento do tambaqui associado à resistência do pacu a temperaturas amenas. Atualmente, outro híbrido bastante produzido é o tambatinga, cruzamento de duas espécies amazônicas (tambaqui x pirapitinga, Piaractus brachypomus) com características produtivas parecidas com as do tambacu, mas com destaque para a cor prateada e o opérculo avermelhado, os quais chamam a atenção do consumidor. Desse modo, este manual vai tratar exclusivamente da tecnologia aplicada à reprodução do tambaqui, desenvolvida pela UFRGS, UEM e UFMT com apoio da Embrapa, por meio do Programa de Melhoramento Genético de Organismos Aquáticos, no âmbito do projeto AQUABRASIL.bitstream/item/83462/1/Doc-212-RecomendacoesTecnicasReproducaoTambaqui.pd
Au Nanoparticles-Mesoporous TiO2 Thin Films Composites as SERS Sensors: A Systematic Performance Analysis
The combination of plasmonic nanoparticles and mesoporous materials is of much interest in applications such as sensing or catalysis. The production of such hybrid materials can be done in various ways, leading to different architectures. We present a comparative study of the SERS performance of different nanocomposite architectures comprising mesoporous TiO2 thin films and Au nanoparticles (NPs). The selection of TiO2 as mesoporous support material was based on its high chemical and mechanical stability. Au NPs of different sizes and shapes were placed at different locations of the composite and used as a plasmonic material compatible with the synthesis conditions of the mesoporous films, displaying a high chemical stability. Using p-nitrothiophenol as a molecular probe, we evaluated the performance toward surface-enhanced Raman scattering (SERS) sensing, on the basis of minimum acquisition time, spot-to-spot reproducibility, and limit of detection. The obtained results indicate that each platform features different sensing capabilities. While systems comprising Au NPs within the mesopores allow working with low acquisition times and present high signal uniformity, only a detection limit of micromolar was achieved. On the other hand, those systems made of branched Au NPs covered with mesoporous films require low acquisition times and can achieve detection limits as low as 10 pM, but signal uniformity is compromised. We propose that careful comparison of different SERS platforms based on Au NPs and mesoporous thin films will facilitate selecting an appropriate configuration for any desired application.Fil: Zalduendo, María Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Langer, Judith. Centro de Investigación Cooperativa en Biomateriales; EspañaFil: Giner Casares, Juan J.. Centro de Investigación Cooperativa en Biomateriales; EspañaFil: Halac, Emilia B.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Soler Illia, Galo Juan de Avila Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martin. Instituto de Nanosistemas; ArgentinaFil: Liz Marzán, Luis M.. Centro de Investigación Cooperativa en Biomateriales; España. Basque Foundation for Science; EspañaFil: Angelome, Paula Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentin
Prediction of the shear strength of reinforced masonry walls using a large experimental database and artificial neural networks
This paper analyses the accuracy of a selection of expressions currently available to estimate the in-plane shear strength of reinforced masonry (RM) walls, including those presented in some international masonry codes. For this purpose, predictions of such expressions are compared with a set of xperimental results reported in the literature. The experimental database includes specimens built with ceramic bricks and concrete blocks tested in partially and fully grouted conditions, which typically present a shear failure mode. Based on the experimental data collected and using artificial neural networks (ANN), this paper presents alternative expressions to the different existing methods to predict the in-plane shear strength of RM walls. The wall aspect ratio, the axial pre-compression level on the wall, the compressive strength of masonry, as well as the amount and spacing of vertical and horizontal reinforcement throughout the wall are taken into consideration as the input parameters for the proposed expressions. The results obtained show that ANN-based proposals give good predictions and in general fit the experimental results better than other calculation methods.This work was supported by the Fondo Nacional de Ciencia y Tecnologia de Chile, (Fondecyt de Iniciacion) [grant number 11121161].Aguilar, V.; Sandoval, C.; Adam Martínez, JM.; Garzón-Roca, J.; Valdebenito, G. (2016). Prediction of the shear strength of reinforced masonry walls using a large experimental database and artificial neural networks. Structure and Infrastructure Engineering. 12(12):1661-1674. https://doi.org/10.1080/15732479.2016.1157824S16611674121
Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)
The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species
Synergistic Degradation Mechanism in Single Crystal Ni-Rich NMC//Graphite Cells
Acknowledgments We acknowledge Diamond Light Source for time on beamline I09 under Proposals SI30201-1 and SI30201-2. This work is supported by the Faraday Institution under Grants FIRG044, FIRG024, and FIRG060.Peer reviewedPublisher PD
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