63 research outputs found
Thermal stratification drives movement of a coastal apex predator
A characterization of the thermal ecology of fishes is needed to better understand changes in ecosystems and species distributions arising from global warming. The movement of wild animals during changing environmental conditions provides essential information to help predict the future thermal response of large marine predators. We used acoustic telemetry to monitor the vertical movement activity of the common dentex (Dentex dentex), a Mediterranean coastal predator, in relation to the oscillations of the seasonal thermocline during two summer periods in the Medes Islands marine reserve (NW Mediterranean Sea). During the summer stratification period, the common dentex presented a clear preference for the warm suprathermoclinal layer, and adjusted their vertical movements following the depth changes of the thermocline. The same preference was also observed during the night, when fish were less active. Due to this behaviour, we hypothesize that inter-annual thermal oscillations and the predicted lengthening of summer conditions will have a significant positive impact on the metabolic efficiency, activity levels, and population dynamics of this species, particularly in its northern limit of distribution. These changes in the dynamics of an ecosystemâs keystone predator might cascade down to lower trophic levels, potentially re-defining the coastal fish communities of the futureVersiĂłn del editor2,92
Premolis semirufa (Walker, 1856) Envenomation, Disease Affecting Rubber Tappers of the Amazon: Searching for Caterpillar-Bristles Toxic Components
Pararama, the popular name of the larval form of the moth Premolis semirufa inhabits rubber plantations in the Amazon region and the accidental contact of the skin with the caterpillar's bristles or cocoons results in immediate and intense heat, pain, edema, and itching. In many cases a chronic inflammatory reaction with immobilization of the joints occurs. The current study has evaluated the biological and immunochemical characteristics of the Pararama caterpillar bristles extract. Electrophoretic analysis showed the presence of several components, including a very intense 82 kDa band. This latter component was endowed with intense gelatinolytic activity, as observed in zymography assays. Further analysis revealed that the extract also contained hyaluronidase activity but is devoid of phospholipase A2 activity. In vivo assays, using mice, showed that the extract was not lethal, but caused significant edema and induced intense infiltration of inflammatory cells to the envenomation site. The extract also induced high specific antibody titers, but no autoantibodies were detected. The data obtained, so far, demonstrate the existence of a mixture of different enzymes in the bristles of Premolis semirufa caterpillar, which can act together in the generation and development of the clinical manifestations of the Pararama envenomation
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Attribution of 2012 extreme climate events: does air-sea interaction matter?
In 2012, extreme anomalous climate conditions occurred around the globe. Large areas of North America experienced an anomalously hot summer, with large precipitation deficits inducing severe drought. Over Europe, the summer of 2012 was marked by strong precipitation anomalies with the UK experiencing its wettest summer since 1912 while Spain suffered severe drought. What caused these extreme climate conditions in various regions in 2012? This study compares attribution conclusions for 2012 climate anomalies relative to a baseline period (1964â1981) based on two sets of parallel experiments with different model configurations (with coupling to an ocean mixed layer model or with prescribed sea surface temperatures) to assess whether attribution conclusions concerning the climate anomalies in 2012 are sensitive to the representation of air-sea interaction. Modelling results indicate that attribution conclusions for large scale surface air temperature (SAT) changes in both boreal winter and summer are generally robust and not very sensitive to air-sea interaction. This is especially true over southern Europe, Eurasia, North America, South America, and North Africa. Some other responses also appear to be insensitive to air-sea interaction: for example, forced increases in precipitation over northern Europe and Sahel, and reduced precipitation over North America and the Amazon in boreal summer. However, the attribution of circulation and precipitation changes for some other regions exhibits a sensitivity to air-sea interaction. Results from the experiments including coupling to an ocean mixed layer model show a positive NAO-like circulation response in the Atlantic sector in boreal winter and weak changes in the East Asian summer monsoon and precipitation over East Asia. With prescribed sea surface temperatures, some different responses arise over these two regions. Comparison with observed changes indicates that the coupled simulations generally agree better with observations, demonstrating that attribution methods based on atmospheric general circulation models have limitations and may lead to erroneous attribution conclusions for regional anomalies in circulation, precipitation and surface air temperature
Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease
Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1ÎČ, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1ÎČ innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
Extrasolar enigmas: from disintegrating exoplanets to exoasteroids
Thousands of transiting exoplanets have been discovered to date, thanks in
great part to the {\em Kepler} space mission. As in all populations, and
certainly in the case of exoplanets, one finds unique objects with distinct
characteristics. Here we will describe the properties and behaviour of a small
group of `disintegrating' exoplanets discovered over the last few years (KIC
12557548b, K2-22b, and others). They evaporate, lose mass unraveling their
naked cores, produce spectacular dusty comet-like tails, and feature highly
variable asymmetric transits. Apart from these exoplanets, there is
observational evidence for even smaller `exo-'objects orbiting other stars:
exoasteroids and exocomets. Most probably, such objects are also behind the
mystery of Boyajian's star. Ongoing and upcoming space missions such as {\em
TESS} and PLATO will hopefully discover more objects of this kind, and a new
era of the exploration of small extrasolar systems bodies will be upon us.Comment: Accepted for publication in the book "Reviews in Frontiers of Modern
Astrophysics: From Space Debris to Cosmology" (eds Kabath, Jones and Skarka;
publisher Springer Nature) funded by the European Union Erasmus+ Strategic
Partnership grant "Per Aspera Ad Astra Simul" 2017-1-CZ01-KA203-03556
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