10 research outputs found

    Studies on the phytoplankton of the deep subalpine Lake Iseo

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    This paper reports the results of investigations carried out on the chemical characteristics and phytoplankton community of Lake Iseo. Samplings were performed on a monthly basis from 1998 to 2000. At least three main algal groups dominated the community throughout the study period. The large Bacillariophyceae were dominant mainly during late winter and early spring (Aulacoseira spp., Melosira varians, Asterionella formosa), with few species able to maintain occasional positive growth also during mid summer and/or autumn (Fragilaria crotonensis and Diatoma elongatum). The thermal stability of the water column and silica depletion were the main factors responsible for the decline of the large spring diatoms. The subsequent growth of Mougeotia sp. (Conjugatophyceae) was favoured by its lower sinking rate and resistance to increasing grazing pressure by the dominant copepods (Copidodiaptomus steueri) and cladocerans (Daphnia hyalina × galeata). Among the cyanobacteria, the greater development of Planktothrix rubescens in the autumn months, with conditions of vertical homogenisation and decreasing Zeu/Zmix ratios, was favoured by its ability to survive at low light irradiances. The temporal replacement of these three groups constitutes the main sequence of the annual phytoplankton succession in Lake Iseo. A large development of other algal groups was recorded only in one or two of the three study years (e.g. Dinophyceae and Chlorococcales). The changes observed in the annual phytoplankton development are discussed in the light of differences in the spring fertilisation of the waters, caused by differences in the depth of the layer involved in the late winter and spring vertical mixing

    Geological storage of CO2 within the oceanic crust by gravitational trapping

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    The rise of atmospheric carbon dioxide (CO2) principally due to the burning of fossil fuels is a key driver of anthropogenic climate change. Mitigation strategies include improved efficiency, using renewable energy, and capture and long-term sequestration of CO2. Most sequestration research considers CO2 injection into deep saline aquifers or depleted hydrocarbon reservoirs. Unconventional suggestions include CO2 storage in the porous volcanic lavas of uppermost oceanic crust. Here we test the feasibility of injecting CO2 into deep-sea basalts and identify sites where CO2 should be both physically and gravitationally trapped. We use global databases to estimate pressure and temperature, hence density of CO2 and seawater at the sediment-basement interface. At previously suggested sites on the Juan de Fuca Plate and in the eastern equatorial Pacific Ocean, CO2 is gravitationally unstable. However, we identify five sediment-covered regions where CO2 is denser than seawater, each sufficient for several centuries of anthropogenic CO2 emissions

    Caves as breeding sites for salamandra salamandra : differences with subterranean artificial springs, pre-metamorphic larval stages and conservation issues

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    Several studies documented the presence of amphibians in caves, yet investigations on the factorsdetermining amphibian distribution and reproduction in underground environments remain scarce. In this study we analyze the environmental features allowing the reproduction of the fire salamander Salamandra salamandra in natural caves, and we compare the features of natural and artificial hypogeous springs. We performed surveys to assess salamander distribution and measured environmental variables in 61 natural caves. We recorded larval occurrence in 18% of caves, in waterbodies distant up to 50 m from the entrance. Larvae were associated to the most accessible caves, with gentle slope below the entrance, with waterbodies nearby the entrance and hosting rich macrobenthos communities. Occupied natural and artificial caves had similar environmental features. Larvae metamorphosing in caves attained larger body size than those grown under outdoor conditions. This result shows the key importance of the cave accessibility also for natural caves and confirms the S. salamandra ability to breed in underground damp biotopes if placed in a suitable environmental context. However, frequent water catchments for human use prevent the access of animals and threaten these populations

    Factors Associated with Risk of Perinatal Depressive Symptoms Among Puerto Rican Women with Hyperglycemia

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    OBJECTIVES: Rates of perinatal depression and pregnancy hyperglycemia are higher in Hispanic women as compared to non-Hispanic white women. In turn, depressive symptoms may reduce a woman\u27s ability to engage in lifestyle changes that could reduce their subsequent diabetes risk. METHODS: We conducted a secondary analysis using data from Estudio Parto to evaluate sociodemographic, behavioral, psychosocial, and medical factors associated with perinatal depressive symptoms. Estudio Parto was a randomized controlled trial conducted in Western Massachusetts from 2013 to 17. Eligible participants had pregnancy hyperglycemia. The Edinburgh Postnatal Depression Scale (EPDS) was administered at 24-28 weeks gestation and at 6 weeks, 6 months, and 12 months postpartum. An EPDS cutpoint of 10 or greater defined the presence of depressive symptoms. RESULTS: In this sample of Puerto Rican women with pregnancy hyperglycemia, 32% and 27% showed prenatal and postpartum depressive symptoms, respectively. Among participants, 35.5% were diagnosed with GDM, 44.3% with isolated hyperglycemia, and 20.2% with impaired glucose tolerance. In multivariable models, being unmarried (OR 3.87; 95% CI 1.51-9.94), prenatal substance use (smoking or alcohol consumption; OR 2.96; 95% CI 1.41-6.18), and maternal age (1.11 for each year; 95% CI 1.04-1.18) were associated with higher odds of prenatal depressive symptoms. None of the risk factors were associated with subsequent postpartum depression in adjusted analyses. CONCLUSIONS: Identifying factors associated with prenatal and postpartum depression in Puerto Rican women with pregnancy hyperglycemia can inform targeted lifestyle interventions in this at-risk group, increase the likely adoption of healthy lifestyle behaviors, and thereby work to address health disparities. CLINICALTRIALS: gov NCT01679210; date of registration 08/07/2012

    MEDICAL SCIENCE. GISSI-2: A factorial randomised trial of alteplase versus streptokinase and heparin versus no heparin among 12 490 patients with acute myocardial infarction

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    A multicentre, randomised, open trial with a 2 x 2 factorial design was conducted to compare the benefits and risks of two thrombolytic agents, streptokinase (SK, 1\ub75 MU infused intravenously over 30-60 min) and alteplase (tPA, 100 mg infused intravenously over 3 h) in patients with acute myocardial infarction admitted to coronary care units within 6 h from onset of symptoms. The patients were also randomised to receive heparin (12 500 U subcutaneously twice daily until discharge from hospital, starting 12 h after beginning the tPA or SK infusion) or usual therapy. All patients without specific contraindications were given atenolol (5-10 mg iv) and aspirin (300-325 mg a day). The end-point of the study was the combined estimate of death plus severe left ventricular damage. 12 490 patients were randomised to four treatment groups (SK alone, SK plus heparin, tPA alone, tPA plus heparin). No specific differences between the two thrombolytic agents were detected as regards the combined end-point (tPA 23\ub71%; SK 22\ub75%; relative risk 1\ub704, 95% Cl 0\ub795-1\ub713), nor after the addition of heparin to the aspirin treatment (hep 22\ub77%, no hep 22\ub79%; RR 0\ub799, 95% Cl 0\ub791-1\ub708). The outcome of patients allocated to the four treatment groups was similar with respect to baseline risk factors such as age, Killip class, hours from onset of symptoms, and site and type of infarct. The rates of major in-hospital cardiac complications (reinfarction, post-infarction angina) were also similar. The incidence of major bleeds was significantly higher in SK and heparin treated patients (respectively, tPA 0\ub75%, SK 1\ub70%, RR 0\ub757, 95% Cl 0\ub738-0\ub785; hep 1\ub70%, no hep 0\ub76%, RR 1\ub764, 95% Cl 1\ub709-2\ub745), whereas the overall incidence of stroke was similar in all groups. SK and tPA appear equally effective and safe for use in routine conditions of care, in all infarct patients who have no contraindications, with or without post-thrombolytic heparin treatment. The 8\ub78% hospital mortality of the study population (compared with approximately 13% in the control cohort of the GISSI-1 trial) indicates the beneficial impact of the proven acute treatments for AMI. \ua9 1990
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