145 research outputs found

    High interannual variability in connectivity and genetic pool of a temperate clingfish matches oceanographic transport predictions

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    Adults of most marine benthic and demersal fish are site-attached, with the dispersal of their larval stages ensuring connectivity among populations. In this study we aimed to infer spatial and temporal variation in population connectivity and dispersal of a marine fish species, using genetic tools and comparing these with oceanographic transport. We focused on an intertidal rocky reef fish species, the shore clingfish Lepadogaster lepadogaster, along the southwest Iberian Peninsula, in 2011 and 2012. We predicted high levels of self-recruitment and distinct populations, due to short pelagic larval duration and because all its developmental stages have previously been found near adult habitats. Genetic analyses based on microsatellites countered our prediction and a biophysical dispersal model showed that oceanographic transport was a good explanation for the patterns observed. Adult sub-populations separated by up to 300 km of coastline displayed no genetic differentiation, revealing a single connected population with larvae potentially dispersing long distances over hundreds of km. Despite this, parentage analysis performed on recruits from one focal site within the Marine Park of Arrabida (Portugal), revealed self-recruitment levels of 2.5% and 7.7% in 2011 and 2012, respectively, suggesting that both long-and short-distance dispersal play an important role in the replenishment of these populations. Population differentiation and patterns of dispersal, which were highly variable between years, could be linked to the variability inherent in local oceanographic processes. Overall, our measures of connectivity based on genetic and oceanographic data highlight the relevance of long-distance dispersal in determining the degree of connectivity, even in species with short pelagic larval durations

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Flexural strength of acrylic resin repairs processed by different methods: water bath, microwave energy and chemical polymerization

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    Denture fractures are common in daily practice, causing inconvenience to the patient and to the dentists. Denture repairs should have adequate strength, dimensional stability and color match, and should be easily and quickly performed as well as relatively inexpensive. OBJECTIVE: The aim of this study was to evaluate the flexural strength of acrylic resin repairs processed by different methods: warm water-bath, microwave energy, and chemical polymerization. MATERIAL AND METHODS: Sixty rectangular specimens (31x10x2.5 mm) were made with warm water-bath acrylic resin (Lucitone 550) and grouped (15 specimens per group) according to the resin type used to make repair procedure: 1) specimens of warm water-bath resin (Lucitone 550) without repair (control group); 2) specimens of warm water-bath resin repaired with warm water-bath; 3) specimens of warm water-bath resin repaired with microwave resin (Acron MC); 4) specimens of warm water-bath resin repaired with autopolymerized acrylic resin (Simplex). Flexural strength was measured with the three-point bending in a universal testing machine (MTS 810 Material Test System) with load cell of 100 kgf under constant speed of 5 mm/min. Data were analyzed statistically by Kruskal-Wallis test (p<0.05). RESULTS: The control group showed the best result (156.04±1.82 MPa). Significant differences were found among repaired specimens and the results were decreasing as follows: group 3 (43.02±2.25 MPa), group 2 (36.21±1.20 MPa) and group 4 (6.74±0.85 MPa). CONCLUSION: All repaired specimens demonstrated lower flexural strength than the control group. Repairs with autopolymerized acrylic resin showed the lowest flexural strength

    THE SERO-CONVERSION AND EVALUATION OF RENAL ALTERATIONS IN DOGS INFECTED BY Leishmania (Infantum) chagasi

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    This study investigated the sero-conversion period in which dogs from endemic areas test positive for visceral leishmaniasis (VL) as well as the early post-infection period in which renal alterations are observed. Dogs that were initially negative for Canine Visceral Leishmaniasis (CVL) were clinically evaluated every three months by serological, parasitological and biochemical tests until sero-conversion was confirmed, and six months later a subsequent evaluation was performed. Samples of kidney tissues were processed and stained with Hematoxylin and Eosin (H&E), Periodic Acid Schiff (PAS) and Massons trichrome stain and lesions were classified based on the WHO criteria. Of the 40 dogs that initially tested negative for VL, 25 (62.5%) exhibited positive serological tests during the study period. Of these 25 dogs, 15 (60%) tested positive within three months, five (20%) tested positive within six months and five (20%) tested positive within nine months. The dogs exhibited antibody titers between 1:40 and 1:80 and 72% of the dogs exhibited clinical symptoms. The Leishmania antigen was present in the kidneys of recently infected dogs. We found higher levels of total protein and globulin as well as lower levels of albumin in the infected dogs when compared to the control dogs. Additionally, infected dogs presented levels of urea and creatinine that were higher than those of the uninfected dogs. Glomerulonephritis was detected in some of the dogs examined in this study. These data suggest that in Teresina, the sero-conversion for VL occurs quickly and showed that the infected dogs presented abnormal serum proteins, as well as structural and functional alterations in the kidneys during the early post-infection period

    Control of Visceral Leishmaniasis in Latin America—A Systematic Review

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    Visceral leishmaniasis is a vector-borne disease characterized by fever, spleen and liver enlargement, and low blood cell counts. In the Americas VL is zoonotic, with domestic dogs as main animal reservoirs, and is caused by the intracellular parasite Leishmania infantum (syn. Leishmania chagasi). Humans acquire the infection through the bite of an infected sand fly. The disease is potentially lethal if untreated. VL is reported from Mexico to Argentina, with recent trends showing a rapid spread in Brazil. Control measures directed against the canine reservoir and insect vectors have been unsuccessful, and early detection and treatment of human cases remains as the most important strategy to reduce case fatality. Well-designed studies evaluating diagnosis, treatment, and prevention/control interventions are scarce. The available scientific evidence reasonably supports the use of rapid diagnostic tests for the diagnosis of human disease. Properly designed randomized controlled trials following good clinical practices are needed to inform drug policy. Routine control strategies against the canine reservoirs and insect vectors are based on weak and conflicting evidence, and vector control strategies and vaccine development should constitute research priorities

    Constipação crônica na infância: quanto estamos consultando em Gastroenterologia Pediátrica?

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    OBJETIVO: Comparar dois períodos em relação ao atendimento de constipação crônica - Tempo A (1992 a 1995) e Tempo B (2002 a 2005), avaliando o número de consultas por problemas gastrintestinais; o número e a porcentagem de consultas de crianças com constipação crônica; e o número de atendimentos de crianças com constipação crônica por período de atendimento. MÉTODOS: No Tempo A, 359 pacientes foram atendidos em um período de quatro horas por semana. No Tempo B, 624 pacientes foram atendidos em três períodos de quatro horas, totalizando 12 horas por semana. RESULTADOS: Houve aumento no número absoluto de pacientes, no número de consultas por problemas gastrintestinais (2,8 vezes) e no número de consultas por constipação crônica (2,6 vezes) no Tempo B, em relação ao Tempo A. Houve manutenção na proporção de consultas por constipação crônica: média de 35,6% no Tempo A e 34,6% no Tempo B. Ocorreu aumento no número de períodos de atendimento no Tempo B (2,9 vezes maior), com igual número de consultas por período de atendimento (média de 17,4 no Tempo A e 16,6 no Tempo B) e de consultas por constipação crônica por período de atendimento (média de 6,1 no Tempo A e 5,5 no Tempo B). CONCLUSÕES: O aumento no número absoluto, e não na proporção de atendimentos por constipação crônica, pode ter ocorrido pela manutenção da prevalência populacional deste distúrbio, gerando demanda contida de encaminhamento pelo pediatra generalista. O despreparo do pediatra generalista para o atendimento deste problema poderia levar a um aumento no número de encaminhamentos aos pediatras especialistas.OBJECTIVE: To compare two periods (A - 1992-1995 and B - 2002-2005) regarding the number of office visits for chronic constipation, considering the number of visits for gastrointestinal problems; the number and percentage of visits for chronic constipation; and the number of visits for constipation per period of care. METHODS: During period A, 359 patients were assisted for a period of four hours/week. During period B, 624 patients were assisted at three different periods of four hours/week. RESULTS: From A to B, there was an increase in: number of patients assisted, number of visits due to gastrointestinal problems (2.8 times) and number of visits due to constipation (2.6 times). However, the proportion of visits due to constipation was similar in both periods (A - 35.6% and B - 34.6%). Also, there was a rise in the number of periods for clinical assistance in Time B (2.9 times greater), with an equal mean number of visits per period (A - 17.4 and B - 16.6) and mean visits due to constipation per period (A- 6.1 and B - 5.5). CONCLUSIONS: The increase number, but not proportion, of visits for constipation may have occurred due to a stable population prevalence of this disorder, generating demand beyond the capacity for referral by generalist pediatricians. Also, the lack of skill of the generalist pediatrician to manage this clinical problem could have increased the number of referrals to specialists
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