502 research outputs found

    Cascading effects of canopy mortality drive long-term changes in understorey diversity in temperate old-growth forests of Europe

    Get PDF
    Questions: We investigated the influence of protracted mortality of a dominant canopy tree (Abies alba) on long-term understorey dynamics. We ask (a) how tree regeneration and understorey species diversity and composition changed over 32 years; and (b) whether the observed changes were mainly driven by mortality of A. alba. Location: Three old-growth forest reserves dominated by A. alba and Fagus sylvatica in the Dinaric Mountains of Slovenia. Method: Tree layer and understorey regeneration and herbs were surveyed in 147 plots across the three forest reserves in 1983 and 2015. Soils were also sampled in 2015. The study period coincides with a protracted period of increased A. alba mortality in the canopy layer associated with anthropogenic emissions. Results: Between 1983 and 2015, the decline in canopy layer A. alba caused a recruitment pulse of F. sylvatica regeneration to the subcanopy tree layer across the three reserves. These changes were accompanied by a significant decline in plot level herb species richness. A model-based analysis of beta-diversity revealed significant community convergence during the study period, mainly caused by the loss of rare species. Ellenberg values indicate that these changes were mainly driven by loss of understorey light, while an increase in soil pH may have played a role also. Conclusions: This observational study suggests that the long-term decline of A. alba resulted in a cascade of processes - widespread F. sylvatica recruitment that impeded penetration of light to the forest floor, and possibly a change in soil conditions due to the decline of coniferous litter. These changes caused a significant loss of herb diversity and homogenization of the understorey community across the three sites. This study sheds light on the potential cascading consequences triggered by episodes of increased tree mortality resulting from global-change-type drivers

    Evaluating the ecological realism of plant species distribution models with ecological indicator values

    Get PDF
    Species distribution models (SDMs) are routinely applied to assess current as well as future species distributions, for example to assess impacts of future environmental change on biodiversity or to underpin conservation planning. It has been repeatedly emphasized that SDMs should be evaluated based not only on their goodness of fit to the data, but also on the realism of the modelled ecological responses. However, possibilities for the latter are hampered by limited knowledge on the true responses as well as a lack of quantitative evaluation methods. Here we compared modelled niche optima obtained from European-scale SDMs of 1,476 terrestrial vascular plant species with empirical ecological indicator values indicating the preferences of plant species for key environmental conditions. For each plant species we first fitted an ensemble SDM including three modeling techniques (GLM, GAM and BRT) and extracted niche optima for climate, soil, land use and nitrogen deposition variables with a large explanatory power for the occurrence of that species. We then compared these SDM-derived niche optima with the ecological indicator values by means of bivariate correlation analysis. We found weak to moderate correlations in the expected direction between the SDM-derived niche optima and ecological indicator values. The strongest correlation occurred between the modelled optima for growing degree days and the ecological indicator values for temperature. Correlations were weaker for SDM-derived niche optima with a more distal relationship to ecological indicator values (notably precipitation and soil moisture). Further, correlations were consistently highest for BRT, followed by GLM and GAM. Our method gives insight into the ecological realism of modelled niche optima and projected core habitats and can be used to improve SDMs by making a more informed selection of environmental variables and modeling techniques

    Rilevazione nazionale in tema di formazione specifica di medicina generale in Italia

    Get PDF
    Physicians have to get a \u201cspecific\u201d diploma attending a threeyear training course provided by each regional health service in order to practice as General Practitioners in Italy. In the last years, there has been an ongoing debate about the need to evolve the specific regional courses into integrated specialization training courses, organized and managed by universities with the contribution of regional health services. The Italian Junior Doctors Association and the Giotto Movement carried out a national survey with the aim to identify strengths and weaknesses of the specific regional training courses. Three-hundred-two junior General Practitioners in training (61,2% females) answered to a web administered questionnaire. Only about half of the recruited trainees has defined as at least \u201csufficient\u201d the training provided by the regional courses. The survey documented in the Italian General Practitioners trainees the need to satisfy an educational demand in order to implement their primary care and general practice skills. In conclusion, this cross-sectional study provided sufficient evidences supporting the evolution of the regional training courses into general practice and primary care specialization schools

    Motivational aspects and level of satisfaction of Italian junior doctors with regard to knowledge and skills acquired attending specific general practice training courses. A national web survey

    Get PDF
    The demographic and epidemiological transitions resulted in a pressing need to reformulate the health workforce demand and to revise pre-and post-graduate training to prepare the medical profiles to meet the new health needs focused on chronic diseases. The Italian Junior Doctors Association and the Giotto Movement carried out a web survey to identify the motivational aspects and the level of satisfaction of Italian junior doctors regarding knowledge and skills acquired after attending the General Practitioners\u2019 specific training (GP-ST). Three-hundred-forty-seven General Practitioners (GPs), 302 trainees and 45 newly qualified trainees answered a web questionnaire. Significant differences (p-value= 0.018) were documented between the two groups regarding the level of satisfaction on the GP-ST. The analysis by geographic macro-areas of the answers given by the 302 trainees showed a heterogeneous level of overall satisfaction (p-value= 0.005). In conclusion, the evidence provided by this cross-sectional study support the proposal to evolve the GP-ST regional courses into general practice and primary care specialization schools

    Ethical issues of unrelated hematopoietic stem cell transplantation in adult thalassemia patients

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Beta thalassemia major is a severe inherited form of hemolytic anemia that results from ineffective erythropoiesis. Allogenic hematopoietic stem cell transplantation (HSCT) remains the only potentially curative therapy. Unfortunately, the subgroup of adult thalassemia patients with hepatomegaly, portal fibrosis and a history of irregular iron chelation have an elevated risk for transplantation-related mortality that is currently estimated to be about 29 percent.</p> <p>Discussion</p> <p>Thalassemia patients may be faced with a difficult choice: they can either continue conventional transfusion and iron chelation therapy or accept the high mortality risk of HSCT in the hope of obtaining complete recovery.</p> <p>Throughout the decision making process, every effort should be made to sustain and enhance autonomous choice. The concept of conscious consent becomes particularly important. The patient must be made fully aware of the favourable and adverse outcomes of HSCT. Although it is the physician's duty to illustrate the possibility of completely restoring health, considerable emphasis should be put on the adverse effects of the procedure. The physician also needs to decide whether the patient is eligible for HSCT according to the "rule of descending order". The patient must be given full details on self-care and fundamental lifestyle changes and be fully aware that he/she will be partly responsible for the outcome.</p> <p>Summary</p> <p>Only if all the aforesaid conditions are satisfied can it be considered reasonable to propose unrelated HSCT as a potential cure for high risk thalassemia patients.</p

    Orchid diversity of the cape of Kamenjak (Istria, Croatia)

    Get PDF
    Twenty two taxa have been recorded in the south of Istrian peninsula (north Adriatic coast, Croatia). The research was performed in the period 2003–2004. A great majority of taxa belong to Euri- Mediterranean (seven taxa, 41.18%) and Steno-Mediterranean (six taxa, 35.29%) floral elements. Eurasiatic (two taxa, 11.76%), Atlantic (one taxa, 5.88%) and endemic (one taxon, 5.88%) plants were also present. Almost a half of recorded orchids are abundant or frequent. The most of taxa are endangered s.l.; nine vulnerable (VU) plants (52.94%), and one species endangered s.s. (EN) (5.88%). There are also near threatened (NT) (two taxa, 11.76%), and data deficient (DD) (one taxon, 5.88%) plants, while others have no category assigned (four taxa, 23.53%)

    A test on Ellenberg indicator values in the Mediterranean evergreen woods (Quercetea ilicis)

    Get PDF
    The consistency and reliability of Ellenberg’s indicator values (Eiv) as ecological descriptors of the Mediterranean evergreen vegetation ascribed to the phytosociological class Quercetea ilicis have been checked on a set of 859 phytosociological relevés × 699 species. Diagnostic species were identified through a Twinspan analysis and their Eiv analyzed and related to the following independent variables: (1) annual mean temperatures, (2) annual rainfall. The results provided interesting insights to disentangle the current syntaxonomical framework at the alliance level demonstrating the usefulness of ecological indicator values to test the efficiency and predictivity of the phytosociological classification

    Agrotóxicos e saúde: realidade e desafios para mudança de práticas na agricultura.

    Get PDF
    Este artigo apresenta os resultados de uma pesquisa que teve como objetivo principal caracterizar o contexto e as práticas relacionadas ao uso de agrotóxicos entre agricultores residentes na Serrinha do Mendanha, comunidade agrícola situada em Campo Grande, município do Rio de Janeiro. A proposta metodológica teve uma abordagem qualitativa, sendo a principal fonte de dados a aplicação de questionário semiestruturado. Participaram da pesquisa 38 agricultores familiares. O perfil socioeconômico mostra uma realidade de idosos no trabalho agrícola, percentuais expressivos de analfabetismo e baixa renda. O uso de agrotóxicos é uma rotina para essas famílias. Apesar de existir uma naturalização do uso, a maioria dos informantes acredita que agrotóxicos podem afetar sua saúde, apresenta preocupação com o consumidor e gostaria de conhecer formas alternativas de cultivo. Tais achados apontam para a possibilidade de busca de mudança de práticas. Não se trata de repasse de conhecimento, pois este tipo de informação de alguma forma eles já possuem. Trata–se de desenvolver estratégias objetivando a minimização dos riscos ou mesmo o desuso de agrotóxicos na lavoura

    Risk-taking in disorders of natural and drug rewards: neural correlates and effects of probability, valence, and magnitude.

    Get PDF
    Pathological behaviors toward drugs and food rewards have underlying commonalities. Risk-taking has a fourfold pattern varying as a function of probability and valence leading to the nonlinearity of probability weighting with overweighting of small probabilities and underweighting of large probabilities. Here we assess these influences on risk-taking in patients with pathological behaviors toward drug and food rewards and examine structural neural correlates of nonlinearity of probability weighting in healthy volunteers. In the anticipation of rewards, subjects with binge eating disorder show greater risk-taking, similar to substance-use disorders. Methamphetamine-dependent subjects had greater nonlinearity of probability weighting along with impaired subjective discrimination of probability and reward magnitude. Ex-smokers also had lower risk-taking to rewards compared with non-smokers. In the anticipation of losses, obesity without binge eating had a similar pattern to other substance-use disorders. Obese subjects with binge eating also have impaired discrimination of subjective value similar to that of the methamphetamine-dependent subjects. Nonlinearity of probability weighting was associated with lower gray matter volume in dorsolateral and ventromedial prefrontal cortex and orbitofrontal cortex in healthy volunteers. Our findings support a distinct subtype of binge eating disorder in obesity with similarities in risk-taking in the reward domain to substance use disorders. The results dovetail with the current approach of defining mechanistically based dimensional approaches rather than categorical approaches to psychiatric disorders. The relationship to risk probability and valence may underlie the propensity toward pathological behaviors toward different types of rewards.This is the final version. It was first published by NPG at http://www.nature.com/npp/journal/v40/n4/full/npp2014242a.htm

    Long-term disease burden and survivorship issues after surgery and radiotherapy of intracranial meningioma patients

    Get PDF
    BACKGROUND Many intracranial meningioma patients have an impaired health-related quality of life (HRQoL) and neurocognitive functioning up to 4 yr after intervention. OBJECTIVE To assess the long-term (≥5 yr) disease burden of meningioma patients. METHODS In this multicenter cross-sectional study, patients ≥5 yr after intervention (including active magnetic resonance imaging (MRI) surveillance) were included and assessed for HRQoL (Short-Form Health Survey 36), neurocognitive functioning (neuropsychological assessment), anxiety and depression (Hospital Anxiety and Depression Scale), and work productivity (Short Form-Health and Labour Questionnaire). Multivariable and propensity score regression analyses were used to compare patients and controls, and different treatment strategies corrected for possible confounders. Clinically relevant differences were reported. RESULTS At a median of 9 yr follow-up after intervention, meningioma patients (n = 190) reported more limitations due to physical (difference 12.5 points, P = .008) and emotional (13.3 points, P = .002) health problems compared with controls. Patients also had an increased risk to suffer from anxiety (odds ratio [OR]: 2.6, 95% CI: 1.2-5.7) and depression (OR: 3.7, 95% CI: 1.3-10.5). Neurocognitive deficits were found in 43% of patients. Although postoperative complications, radiotherapy, and reresection were associated with worse verbal memory, attention, and executive functioning when compared to patients resected once, the only clinically relevant association was between reresection and worse attention (–2.11, 95% CI: –3.52 to –0.07). Patients of working age less often had a paid job (48%) compared with the working-age Dutch population (72%) and reported more obstacles at work compared with controls. CONCLUSION In the long term, a large proportion of meningioma patients have impaired HRQoL, neurocognitive deficits, and high levels of anxiety or depression. Patients treated with 1 resection have the best neurocognitive functioning
    corecore