121 research outputs found
Panmixia in a fragmented and unstable environment: the hydrothermal shrimp Rimicaris exoculata disperses extensively along the Mid-Atlantic ridge
Dispersal plays a fundamental role in the evolution and persistence of species, and especially for species inhabiting extreme,
ephemeral and highly fragmented habitats as hydrothermal vents. The Mid-Atlantic Ridge endemic shrimp species Rimicaris exoculata was studied using microsatellite markers to infer connectivity along the 7100-Km range encompassing the sampled sites. Astonishingly, no genetic differentiation was found between individuals from the different geographic origins, supporting a scenario of widespread large-scale dispersal despite the habitat distance and fragmentation. We hypothesize that delayed metamorphosis associated to temperature differences or even active directed migration
dependent on physical and/or chemical stimuli could explain these results and warrant further studies on adaptation and
dispersal mechanisms
Search for Higgs boson pair production in the gamma gamma b(b)over-bar final state in pp collisions at root s=13 TeV
A search is presented for the production of a pair of Higgs bosons, where one decays into two photons and the other one into a bottom quark-antiquark pair. The analysis is performed using proton-proton collision data at root s = 13 TeV recorded in 2016 by the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb(-1) . The results are in agreement with standard model (SM) predictions. In a search for resonant production, upper limits are set on the cross section for new spin-0 or spin-2 particles. For the SM-like nonresonant production hypothesis, the data exclude a product of cross section and branching fraction larger than 2.0 fb at 95% confidence level (CL), corresponding to about 24 times the SM prediction. Values of the effective Higgs boson self-coupling K X are constrained to be within the range -11 < K-lambda < 17 at 95% CL, assuming all other Higgs boson couplings are at their SM value. The constraints on K-lambda, are the most restrictive to date. (C) 2018 The Author(s). Published by Elsevier B.V.Peer reviewe
Diabetic ketoacidosis
Diabetic ketoacidosis (DKA) is the most common acute hyperglycaemic emergency in people with diabetes mellitus. A diagnosis of DKA is confirmed when all of the three criteria are present — ‘D’, either elevated blood glucose levels or a family history of diabetes mellitus; ‘K’, the presence of high urinary or blood ketoacids; and ‘A’, a high anion gap metabolic acidosis. Early diagnosis and management are paramount to improve patient outcomes. The mainstays of treatment include restoration of circulating volume, insulin therapy, electrolyte replacement and treatment of any underlying precipitating event. Without optimal treatment, DKA remains a condition with appreciable, although largely preventable, morbidity and mortality. In this Primer, we discuss the epidemiology, pathogenesis, risk factors and diagnosis of DKA and provide practical recommendations for the management of DKA in adults and children
Reproductive biology of female Amazonian brocket deer in northeastern Peru
The aim of this study was to provide information on the reproductive biology of brocket deer. Hence, we analyzed female reproductive tracts collected by rural hunters from 1991 to 1998 in the Tamshiyacu-Tahuayo Communal Reserve, northeastern Peruvian Amazon. We characterized the basic reproductive biology of brocket deer, analyzed whether the distributions of conceptions and births are aseasonal, and compared their reproductive productivity in two different areas subject to heavy and slight hunting pressures, respectively. We found that: (1) red and gray brocket deer did not differ in ovulation, fertilization, and pregnancy rates; (2) average number of fetuses per birth was 1.2 for red brocket deer and one for gray brocket deer; (3) sex of fetuses suggests a male biased sex ratio for both species; (4) neither species shows reproductive seasonality; and (5) gross productivity does not differ between heavily and slightly hunted areas. Our results indicate that brocket deer exhibit reproductive characteristics similar to their conspecifics in other parts of their native distribution range
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