5,173 research outputs found

    Functional traits reveal coastal vegetation assembly patterns in a short edaphic gradient in southern Brazil

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    The relationship between plant functional traits and soil variables is useful for understanding plant community composition and circumscribing plant functional groups to highlight their adaptations to environmental conditions. The principal aim of this study was to explain assembly patterns of coastal vegetation using functional traits along a short edaphic gradient. The work was carried out on the pioneer zone in the coastal lowland vegetation (foredune) in southern Brazil. We selected 40 functional traits related to the morphology and anatomy of leaves, stems and roots for 60 species recorded in 25 vegetation plots positioned along three transects from the shoreline to slacks. In each plot, floristic and soil data were collected, and functional traits measured. We analysed the relationships between species functional traits and soil factors through RLQ and fourth-corner analyses. Salinity and organic matter content were the most significant edaphic factors in the differentiation of foredune vegetation, while the most significant traits to explain plant adaptations to coastal environments were plant height, sclerenchyma, spongy parenchyma and reserves of inulin in the root. Two functional groups of plants were circumscribed: a conservative group formed by trees and shrubs dominated the Woody Community, with low values of SLA (specific leaf area), thick cuticles, high frequencies of phenolic compounds and crystals, woody stems and great plant heights, which tended to invest in permanent aerial organs; and a more heterogeneous group of herbaceous plants (found in Beach Community, Non-floodable, and Wet Communities) with acquisitive characteristics (high SLA values) or conservative strategy (rhizome and xylopodium). Finally, our results suggested that root and stem functional traits, which are infrequently taken into consideration, were useful to differentiate subtropical coastal plants and, in general, to study plant adaptations to environmental conditions in depth

    Tibouchina sellowiana (Cham.) Cogn.: enraizamento, anatomia e análises bioquímicas nas quatro estações do ano.

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    O presente trabalho buscou verificar os efeitos da aplicação de diferentes concentrações do ácido indolbutírico (AIB), em talco e em solução, no enraizamento de estacas caulinares de Tibouchina sellowiana (Cham.) Cogn. coletadas nas quatro estações do ano, bem como suas variações anatômicas e bioquímicas. Estacas semilenhosas foram tratadas com 0, 1500 e 3000 mg L-1 de ácido indolbutírico (AIB), em talco e solução 50% alcoólica. Após 65 dias em casa-de-vegetação, foram avaliados a porcentagem de estacas enraizadas, o número e o comprimento das raízes, a porcentagem de estacas com calos e a sobrevivência. O uso do AIB mostrou-se eficiente na indução radicial, sendo indiferente a forma em que foi aplicado. As estações mais promissoras foram a primavera (78,75%) com 3.000 mg L-1 ou mg kg-1 de AIB e o verão (63,12%) com 1.500 mg L-1 ou mg kg-1 de AIB. Das secções feitas na base das estacas, no momento da estaquia, não foi detectada nenhuma possível barreira anatômica ou diferença estrutural que promovesse variações no enraizamento. Análises bioquímicas feitas das estacas revelaram que as maiores concentrações de açúcares totais foram obtidas no inverno (83,21 mg g-1 de tecido) e no outono (72,79 mg g-1), as estações que também apresentaram as maiores concentrações de proteínas (4,69 e 3,95 mg g-1 respectivamente)

    Symmetric Hyperbolic System in the Self-dual Teleparallel Gravity

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    In order to discuss the well-posed initial value formulation of the teleparallel gravity and apply it to numerical relativity a symmetric hyperbolic system in the self-dual teleparallel gravity which is equivalent to the Ashtekar formulation is posed. This system is different from the ones in other works by that the reality condition of the spatial metric is included in the symmetric hyperbolicity and then is no longer an independent condition. In addition the constraint equations of this system are rather simpler than the ones in other works.Comment: 8 pages, no figure

    A microseismic study in a low seismicity area of Italy: the Città di Castello 2000-2001 experiment

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    Recent seismological studies contribute to better understand the first order characteristics of earthquake occurrence in Italy, identifying the potential sites for moderate to large size earthquakes. Ad hoc passive seismic experiments performed in these areas provide information to focus on the location and geometry of the active faults more closely. This information is relevant for assessing seismic hazard and for accurately constraining possible ground shaking scenarios. The area around the Città di Castello Basin, in the Northern Apennines (Central Italy), is characterized by the absence of instrumental seismicity (M > 2.5), it is adjacent to faults ruptured by recent and historical earthquakes. To better understand the tectonics of the area, we installed a dense network of seismic stations equipped with broadband and short period seismometers collecting data continuously for 8 months (October 2000-May 2001). The processing of ~ 900 Gbyte of data revealed a consistent background seismicity consisting of very low magnitude earthquakes (ML < 3.2). Preliminary locations of about 2200 local earthquakes show that the area can be divided into two regions with different seismic behaviour: an area to the NW, in between Sansepolcro and Città di Castello, where seismicity is not present. An area toward the SE, in between Città di Castello, Umbertide and Gubbio, where we detected a high microseismicity activity. These findings suggest a probable different mechanical behaviour of the two regions. In the latter area, the seismicity is confined between 0 and 8 km of depth revealing a rather well defined east-dipping, low angle fault 35 km wide that cuts through the entire upper crust down to 12-15 km depth. Beside an apparent structural complexity, fault plane solutions of background seismicity reveal a homogeneous pattern of deformation with a clear NE-SW extension

    Menstrual pattern and menstrual disorders among adolescents: an update of the Italian data.

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    Abstract Background The most striking event in the whole process of female puberty is the onset of menstruation. To our knowledge, no large population-based studies have been performed on the topic of menstrual health among Italian adolescents in recent years. The aims of this study were to produce up-to-date information on the menstrual pattern of Italian girls attending secondary school, and to estimate the prevalence of menstrual cycle abnormalities in this population. Methods This was a cross-sectional study on a population-based sample of Italian adolescents aged 13–21 years attending secondary school. Only girls who had already started menstruating were requested to participate. Information was collected by means of a questionnaire that included items on the girls’ demographic details, anthropometrics, smoking and drinking habits, use of contraceptive pills, and socioeconomic status. The questions on the girls’ menstrual pattern concerned their age at menarche, duration of the most recent menstruation intervals (35 days, variable), average days of bleeding (6 days), and any menstrual problems and their frequency. Results A total of 6,924 questionnaires were administered and 4,992 (71%) were returned. One hundred girls failed to report their date of birth, so 4,892 subjects were analyzed. The girls’ mean age was 17.1 years (SD ±1.4); their mean age at menarche was 12.4 (±1.3) years, median 12.4 years (95%CI 12.3–12.5). In our sample population, 3.0% (95%CI 2.5%-3.4%) of the girls had menstruation intervals of less than 21 days, while it was more than 35 days in 3.4% (95%CI 2.9%-3.9%). About 9% of the girls (95%CI 7.7%-9.4%) said the length of their menstruation interval was currently irregular. Short bleeding periods (6 days) in 19% (95%CI 17.9%-20.1%). Menstruation-related abdominal pain was reported by about 56% of our sample. About 6.2% of the girls (95%CI 5.4%-7.0%) were suffering from dysmenorrhea. Conclusions In conclusion, to the best of our knowledge, this is one of the largest studies on menstrual patterns and menstrual disorders among Italian adolescent girls. Adolescent girls referring persistent oligomenorrhoea, in first two years from menarche, had a higher risk for developing a persistent menstrual irregularity. They had longer bleeding periods (>6 days) and this has practical implications because it makes these adolescents potentially more susceptible to iron deficiency anemia. Clinicians need to identify menstrual abnormalities as early as possible in order to minimize their possible consequences and sequelae, and to promote proper health information. We recommend that adolescents should be encouraged to chart their menstrual frequency and regularity prospectively from the menarche onwards.</p

    Defective Function of the Fas Apoptotic Pathway in Type 1 Diabetes Mellitus Correlates with Age at Onset

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    The Fas death receptor triggers lymphocyte apoptosis through an extrinsic and an intrinsic pathway involving caspase-8 and -9 respectively. Inherited defects of Fas function are displayed by a proportion of patients with Type 1 diabetes mellitus (T1DM) especially those with a second autoimmunity (T1DM-p). This study assesses activation of both pathways in Fas-resistant (FasR) patients to localize the defect. 21/28 (75%) T1DM-p, 14/50 (38%) T1DM, and 7/150 (5%) controls were FasR. Analysis of the 35 FasR patients and 20 Fas-sensitive (FasS) controls showed that caspase-9 activity was lower in T1DM-p and T1DM than in controls, whereas caspase-8 activity was lower in T1DM-p than in T1DM and the controls. Single patient analysis showed that 16/35 patients displayed defective activity of one (FasR1), whereas 19 displayed normal activity of both caspases (FasR2) Ages at onset of diabetes mellitus in T1DM and the second autoimmune disease in T1DM-p were lower in FasR than in FasS patients. All FasR1 patients developed diabetes mellitus before the age of 9 years, whereas a later onset was displayed by 26% FasR2 and 53% FasS patients. These data show that defective Fas function may involve both the extrinsic and intrinsic pathway in T1DM and severity correlates with the precocity of the autoimmune attack and its tissue polyreactivity

    The 2012 Emilia seismic sequence (Northern Italy): Imaging the thrust fault system by accurate aftershock location

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    Starting from late May 2012, the Emilia region (Northern Italy) was severely shaken by an intense seismic sequence, originated from a ML 5.9 earthquake on May 20th, at a hypocentral depth of 6.3 km, with thrusttype focal mechanism. In the following days, the seismic rate remained high, counting 50 ML ≥ 2.0 earthquakes a day, on average. Seismicity spreads along a 30 km east–west elongated area, in the Po river alluvial plain, in the nearby of the cities Ferrara and Modena. Nine days after the first shock, another destructive thrust-type earthquake (ML 5.8) hit the area to the west, causing further damage and fatalities. Aftershocks following this second destructive event extended along the same east-westerly trend for further 20 km to the west, thus illuminating an area of about 50 km in length, on thewhole. After the first shock struck, on May 20th, a dense network of temporary seismic stations, in addition to the permanent ones, was deployed in the meizoseismal area, leading to a sensible improvement of the earthquake monitoring capability there. A combined dataset, including threecomponent seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the thrust system responsible for the two strongest shocks

    Bayesian Fit of Exclusive b→sℓˉℓb \to s \bar\ell\ell Decays: The Standard Model Operator Basis

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    We perform a model-independent fit of the short-distance couplings C7,9,10C_{7,9,10} within the Standard Model set of b→sγb\to s\gamma and b→sℓˉℓb\to s\bar\ell\ell operators. Our analysis of B→K∗γB \to K^* \gamma, B→K(∗)ℓˉℓB \to K^{(*)} \bar\ell\ell and Bs→μˉμB_s \to \bar\mu\mu decays is the first to harness the full power of the Bayesian approach: all major sources of theory uncertainty explicitly enter as nuisance parameters. Exploiting the latest measurements, the fit reveals a flipped-sign solution in addition to a Standard-Model-like solution for the couplings CiC_i. Each solution contains about half of the posterior probability, and both have nearly equal goodness of fit. The Standard Model prediction is close to the best-fit point. No New Physics contributions are necessary to describe the current data. Benefitting from the improved posterior knowledge of the nuisance parameters, we predict ranges for currently unmeasured, optimized observables in the angular distributions of B→K∗(→Kπ) ℓˉℓB\to K^*(\to K\pi)\,\bar\ell\ell.Comment: 42 pages, 8 figures; v2: Using new lattice input for f_Bs, considering Bs-mixing effects in BR[B_s->ll]. Main results and conclusion unchanged, matches journal versio
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