1,022 research outputs found

    Bryophytes: how to conquer an alien planet and live happily (ever after)

    Get PDF
    There are many push and pull factors that commonly drive individuals to leave their homeland. For example, escaping competition and occupying a novel habitat undoubtedly offer the advantage of new opportunities to pilgrims, but the absence of unfavorable biotic interactions can be counterbalanced by other antagonistic abiotic forces. After all, conquering an alien planet is not now nor ever was an easy task. We cannot know how many attempts and failures have punctuated the journey that led ancestral, photosynthetic organisms to leave the aquatic world and successfully establish on dry land. However, some traits developed by the ancestors of modern bryophytes that allowed them to adapt their life cycle to such a different habitat and persist there, have been undoubtedly identified

    Neuro-hormonal effects of physical activity in the elderly.

    Get PDF
    Thanks to diagnostic and therapeutic advances, the elderly population is continuously increasing in the western countries. Accordingly, the prevalence of most chronic age-related diseases will increase considerably in the next decades, thus it will be necessary to implement effective preventive measures to face this epidemiological challenge. Among those, physical activity exerts a crucial role, since it has been proven to reduce the risk of cardiovascular diseases, diabetes, obesity, cognitive impairment and cancer. The favorable effects of exercise on cardiovascular homeostasis can be at least in part ascribed to the modulation of the neuro-hormonal systems implicated in cardiovascular pathophysiology. In the elderly, exercise has been shown to affect catecholamine secretion and biosynthesis, to positively modulate the renin-angiotensin-aldosterone system and to reduce the levels of plasma brain natriuretic peptides. Moreover, drugs modulating the neuro-hormonal systems may favorably affect physical capacity in the elderly. Thus, efforts should be made to actually make physical activity become part of the therapeutic tools in the elderly. © 2013 Femminella, de Lucia, Iacotucci, Formisano, Petraglia, Allocca, Ratto, DAmico, Rengo, Pagano, Bonaduce, Rengo and Ferrara

    Refugial peatlands in the Northern Apennines. Vegetation-environment relationships and future perspectives

    Get PDF
    Aims: We aimed to detect the environmental drivers conditioning plant diversity and to predict how modifications in habitat conditions and ongoing global warming could lead to vegetation changes or biodiversity losses in a region especially rich in peatlands despite its relatively low latitude. Study area: The study area was located in the Northern Apennines, Northern Italy (about 44 degrees 45' N; 10 degrees 20' E). The vegetation study was carried out at 12 peatland sites where 206 plots were set up. Species composition in the 206 plots were recorded in the field and classified with cluster analysis. Data on hydrology, water chemistry and peat chemistry were collected at a subset of 127 plots and statistically analysed by a multivariate ordination method. Species richness and evenness were calculated for all plots. Relationships between species composition and environmental variables were analysed by stepwise multiple regression. Results: The cluster analysis defined 17 vegetation units. Water table depth represented the major environmental factors accounting for vegetation patterns, with the vegetation units being grouped in four main blocks based on vegetation physiognomy and species composition: Sphagnum hummocks, Sphagnum lawns, fens and pools. Water chemistry and peat chemistry both presented moderate variations among the vegetation units with mean water pH ranging from 4.9 to 6.3. Concentrations of major cations in the pore water showed that all of the habitats investigated were influenced by telluric water, with no evidence of ombrotrophic conditions. Species richness and evenness both presented poor relations with the environment while responses of individual species to environmental factors were more informative on vegetation changes triggered by climate change. Conclusions: Prolonged drought events associated with high temperature in summer months are expected to exert a strong impact on peatland vegetation. The main effect of climate change on the vegetation of the peatlands investigated consists in the spreading of vascular plants at the expense of Sphagnum mosses

    Assessment of the radiological impact of a decommissioning nuclear power plant in Italy

    Get PDF
    The assessment of the radiological impact of a decommissioning Nuclear Power Plant is presented here through the results of an environmental monitoring survey carried out in the area surrounding the Garigliano Power Plant. The levels of radioactivity in soil, water, air and other environmental matrices are shown, in which {\alpha}, {\beta} and {\gamma} activity and {\gamma} equivalent dose rate are measured. Radioactivity levels of the samples from the Garigliano area are analyzed and then compared to those from a control zone situated more than 100 km away. Moreover, a comparison is made with a previous survey held in 2001. The analyses and comparisons show no significant alteration in the radiological characteristics of the area surroundings the plant, with an overall radioactivity depending mainly from the global fallout and natural sources

    Assessment of the radiological impact of a decommissioning nuclear power plant in Italy

    Full text link
    The assessment of the radiological impact of a decommissioning Nuclear Power Plant is presented here through the results of an environmental monitoring survey carried out in the area surrounding the Garigliano Power Plant. The levels of radioactivity in soil, water, air and other environmental matrices are shown, in which {\alpha}, {\beta} and {\gamma} activity and {\gamma} equivalent dose rate are measured. Radioactivity levels of the samples from the Garigliano area are analyzed and then compared to those from a control zone situated more than 100 km away. Moreover, a comparison is made with a previous survey held in 2001. The analyses and comparisons show no significant alteration in the radiological characteristics of the area surroundings the plant, with an overall radioactivity depending mainly from the global fallout and natural sources.Comment: 13 pages, 6 figures, 2 table

    Reduced Admissions for Cerebrovascular Events during COVID-19 Outbreak in Italy

    Get PDF
    Background and Purpose: We aimed to investigate the rate of hospital admissions for cerebrovascular events and of revascularization treatments for acute ischemic stroke in Italy during the coronavirus disease 2019 (COVID-19) outbreak. Methods: The Italian Stroke Organization performed a multicenter study involving 93 Italian Stroke Units. We collected information on hospital admissions for cerebrovascular events from March 1 to March 31, 2020 (study period), and from March 1 to March 31, 2019 (control period). Results: Ischemic strokes decreased from 2399 in 2019 to 1810 in 2020, with a corresponding hospitalization rate ratio (RR) of 0.75 ([95% CI, 0.71-0.80] P<0.001); intracerebral hemorrhages decreased from 400 to 322 (hospitalization RR, 0.81 [95% CI, 0.69-0.93]; P=0.004), and transient ischemic attacks decreased from 322 to 196 (hospitalization RR, 0.61 [95% CI, 0.51-0.73]; P<0.001). Hospitalizations decreased in Northern, Central, and Southern Italy. Intravenous thrombolyses decreased from 531 (22.1%) in 2019 to 345 in 2020 (19.1%; RR, 0.86 [95% CI, 0.75-0.99]; P=0.032), while primary endovascular procedures increased in Northern Italy (RR, 1.61 [95% CI, 1.13-2.32]; P=0.008). We found no correlation (P=0.517) between the hospitalization RRs for all strokes or transient ischemic attack and COVID-19 incidence in the different areas. Conclusions: Hospitalizations for stroke or transient ischemic attacks across Italy were reduced during the worst period of the COVID-19 outbreak. Intravenous thrombolytic treatments also decreased, while endovascular treatments remained unchanged and even increased in the area of maximum expression of the outbreak. Limited hospitalization of the less severe patients and delays in hospital admission, due to overcharge of the emergency system by COVID-19 patients, may explain these data

    Histological analysis of thrombi retrieved after acute ischemic stroke from large vessel occlusion: from research to clinical practice

    Get PDF
    Emergent reperfusion therapies have improved acute ischemic stroke prognosis, but many patients are still bound to bad clinical outcome, probably because of our incomplete knowledge of its pathophysiology. Thanks to mechanical thrombectomy, occluding material is available for histological analysis. Several studies investigated the possible relationship between thrombus composition and clinical, procedural, and radiological variables of acute ischemic stroke. The potential value of thrombus analysis as a tool for clinical practice and research is still not defined, as data from the literature are heterogeneous and sometimes conflicting. We propose a review of the existing literature regarding histological analysis of thrombi in acute ischemic stroke. We classified articles on clot composition according to the clinical variable explored in each study. We first distinguished articles about etiology, procedural, and radiological variables, and then we performed a subclassification for each group. This review could help both in the interpretation of thrombus analysis in clinical practice and in its usage for future researc

    Exaptation traits for megafaunal Mutualisms as a factor in plant domestication

    Get PDF
    Megafaunal extinctions are recurring events that cause evolutionary ripples, as cascades of secondary extinctions and shifting selective pressures reshape ecosystems. Megafaunal browsers and grazers are major ecosystem engineers, they: keep woody vegetation suppressed; are nitrogen cyclers; and serve as seed dispersers. Most angiosperms possess sets of physiological traits that allow for the fixation of mutualisms with megafauna; some of these traits appear to serve as exaptation (preadaptation) features for farming. As an easily recognized example, fleshy fruits are, an exaptation to agriculture, as they evolved to recruit a non-human disperser. We hypothesize that the traits of rapid annual growth, self-compatibility, heavy investment in reproduction, high plasticity (wide reaction norms), and rapid evolvability were part of an adaptive syndrome for megafaunal seed dispersal. We review the evolutionary importance that megafauna had for crop and weed progenitors and discuss possible ramifications of their extinction on: (1) seed dispersal; (2) population dynamics; and (3) habitat loss. Humans replaced some of the ecological services that had been lost as a result of late Quaternary extinctions and drove rapid evolutionary change resulting in domestication.Introduction Lost Seed-Dispersal Services - Small-Seeded Grains and Legumes - Large Fleshy Fruiting Plants Loss of Herbivory and Disturbance Regimes Plant Domestication - Exaptation Traits Supporting Domestication Anthropogenic Ecosystem Service

    Reply to Westaway and Lyman: emus, dingoes, and archaeology’s role in conservation biology

    Get PDF
    In a curious comment on our PNAS Perspective, Westaway and Lyman offer two Australian zooarchaeological case studies—one involving eggshells and the other dingoes—that they argue undercut one of our main points: that archaeological data and deep time perspectives have much to offer conservation biology. Neither example provides a specific substantive critique of our perspective: there are no dingoes in our article, no eggshells, and we mention the long and rich record of human management and alteration of Australian environments only briefly. Nor do we suggest that all archaeological assemblages can effectively inform current conservation biology efforts. Such datasets obviously vary in their quality and potential applicability to modern situations. When considered more closely, both of Westaway and Lyman’s case studies underscore rather than undercut the importance of archaeological and paleoecological data in conservation biology initiatives

    Wind turbine wake properties: Comparison between a non-rotating simplified wind turbine model and a rotating model

    Get PDF
    Experimental results on the wake properties of a non-rotating simplified wind turbine model, based on the actuator disc concept, and a rotating model, a three-blade wind turbine, are presented. Tests were performed in two different test sections, one providing a nominally decaying isotropic turbulent inflow (turbulence intensity of 4% at rotor disc location) and one providing a neutral atmospheric boundary layer above a moderately rough terrain at a geometric scale of 1:300 (determined from the combination of several indicators), with 13% of turbulence intensity at hub height. The objective is to determine the limits of the simplified wind turbine model to reproduce a realistic wind turbine wake. Pressure and high-order velocity statistics are therefore compared in the wake of both rotor discs for two different inflow conditions in order to quantify the influence of the ambient turbulence. It has been shown that wakes of rotating model and porous disc developing in the modeled atmospheric boundary layer are indistinguishable after 3 rotor diameters downstream of the rotor discs, whereas few discrepancies are still visible at the same distance with the decaying isotropic turbulent inflow
    corecore