78 research outputs found

    VARIAÇÕES da Comunicadade Fitoplanctonica na Regiao Estuarina dos Rios Piraque-açu e Piraquq-mirim (aracruz-es) e Suas RelaçÔes Com Os Fatores Ambientais

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    RESUMO O presente trabalho foi realizado no estuĂĄrio dos rios PiraquĂȘ-AçĂș e PiraquĂȘ-Mirim, localizado no municĂ­pio de Aracruz - ES (Brasil). Este estudo teve como objetivo estudar espacial e temporalmente a comunidade fitoplanctĂŽnica do estuĂĄrio nos seus aspectos qualitativos e quantitativos, avaliando tambĂ©m a biomassa do fitoplĂąncton presente atravĂ©s da tĂ©cnica do biovolume. AlĂ©m disso, as variĂĄveis abiĂłticas (nutrientes, pH, salinidade, temperatura, transparĂȘncia e oxigĂȘnio dissolvido na ĂĄgua) foram relacionadas com variĂĄveis biĂłticas do fitoplĂąncton analisadas nos mesmos pontos, dispostos ao longo do estuĂĄrio. Os resultados obtidos basearam-se em amostragens realizadas bimestralmente no perĂ­odo de agosto de 2003 a fevereiro de 2004 em quatro pontos de amostragem no estuĂĄrio. As concentraçÔes de feofitina foram superiores as concentraçÔes de clorofila a, o que demonstrou um grau de senescĂȘncia elevado da comunidade. Quanto ao aspecto qualitativo do fitoplĂąncton foram encontrados 156 tĂĄxons identificados Ă  nĂ­vel de espĂ©cie, gĂȘnero e variedade, sendo que a maioria destes podem ser considerados marinhos, eurialinos e planctĂŽnicos. As Classes dominantes foram Bacillariophyceae (57%), Chlorophyceae (11,5%) e Dinophyceae (8,4%). Apesar da grande riqueza de espĂ©cies que caracterizou o fitoplĂąncton do Rio PiraquĂȘ-AçĂș e PiraquĂȘ-Mirim, apenas algumas espĂ©cies foram de real importĂąncia quantitativa, dentre elas a Cyanophyceae Synechocystis aquatilis, a Chlorophyceae Chlorella minutissima e a Bacillariophyceae Melosira varians. Os maiores valores de densidade numĂ©rica total ocorreram no perĂ­odo chuvoso (fevereiro). Tais variaçÔes estĂŁo relacionadas ao maior aporte de material alĂłctone e nutrientes provenientes do escoamento superficial durante o perĂ­odo chuvoso. Quanto ao biovolume celular sete Classes contribuĂ­ram representativamente: Chlorophyceae, Bacillariophyceae, Cyanophyceae, Dinophyceae, Cryptophyceae, Euglenophyceae e os fitoflagelados. A maior contribuição para o biovolume total foi dada pelas Bacillariophyceae e 7 Dinophyceae. A pluviosidade foi o principal transformador externo capaz de induzir mudanças sobre o fitoplĂąncton. ABSTRACT This study was carried out in the estuary of the PiraquĂȘ- AçĂș and PiraquĂȘ-Mirim rivers, located in the municipal district of Aracruz-ES (Brazil). The aim of this study is to verify both spatial and temporal changes on phytoplanktonic community of the estuary in its qualitative and quantitative aspects, and also to evaluate the biomass through the technique of biovolume. Moreover, the obtained biotics variables were related with abiotic variables analized at the same spots along the estuary. The obtained results were based on samplings carried out bimonthly in the period of August 2003 to February 2004, emphasizing two pluviometric seasons: dry (August) and rainy (February). Pheopigments concentrations were higher than chlorophyll a concentration, showing a senescent degree of the community. The qualitative aspect of the phytoplankton community showed 156 taxons classified in species, genus and varieties, wich most of them considered as marine, eurialine and planktonic. The dominant classes were Bacillariophyceae (57%), Chlorophyceae (11,5%) and Dinophyceae (8,4%). Although, the community showed a higher diversity, just some were quantitatively significant, among them Cyanophyceae Synechocystis aquatilis, Chlorophyceae Chlorella minutissima and Bacillariophyceae Melosira varians. The highest densities of total phytoplankton occured in the rainy season. Such variations were related to a significant contribution of allochthonous nutrients and materials originated from superficial outflow during the rainy season. Regarding the biovolume, seven classes of algae showed significative contribution: Chlorophyceae, Bacillariophyceae, Cyanophyceae, Dinophyceae, Cryptophyceae, Euglenophyceae and the phytoflagellates. The most significant contribution for total biovolume was given by Bacillariophyceae and Dinophyceae. Pluviosity was the major external driving force leading to changes in phytoplankton community

    Using SPOT Data and FRAGSTAS to Analyze the Relationship between Plant Diversity and Green Space Landscape Patterns in the Tropical Coastal City of Zhanjiang, China

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    Urban green spaces provide a host of ecosystem services, the quantity and structure of which play an important role in human well-being. Rapid urbanization may modify urban green spaces, having various effects on plant diversity. Tropical coastal cities have urbanized rapidly in recent decades, but few studies have been conducted with a focus on their green spaces. We studied the responses of cultivated and spontaneous plants, both key components of urban flora, to the landscape structure of urban green spaces and possible social drivers. We analyzed existing relationships between plant diversity indices, urban green space landscape metrics (using Systeme Probatoire d’Observation de la Terre (SPOT) data,), and social factors, including the type, population density, construction age, and GPS coordinates of each Urban Functional Unit, or UFU. We found that UFUs with more green space patches had higher cultivated and spontaneous species richness than those with fewer green space patches. Spontaneous species richness decreased when green space patches became fragmented, and it increased when green space patches were more connected (e.g., via land bridges). Conversely, cultivated species richness increased with green space patch fragmentation. The phylogenetic diversity of both cultivated and spontaneous plants were weakly associated with green space structure, which was strongly driven by land use. Old UFUs and those with larger populations had more green space patches overall, although they tended to be small and fragmented. Green space patch density was found to increase as the UFU age increased. From the viewpoint of knowledge transfer, understanding the effects and drivers of landscape patterns of urban green spaces could inform the development of improved policies and management of urban green space areas.Peer Reviewe

    Visiting urban green space as a climate-change adaptation strategy: Exploring push factors in a push–pull framework

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    Urban green space (UGS) offers users multiple ecosystem services and amenities. This study investigated whether residents used UGS visitation in summer as a sustainable measure to tackle hot weather and associated climate-change impacts in humid-subtropical Hong Kong. Attributes of the indoor residential environment, seldom examined in park-visitation studies, were evaluated as push factors to visit UGS through a push–pull theoretical framework. A questionnaire survey of 483 respondents targeted urban park users. The results indicated that UGS visit frequency and stay duration were relatively low in hot summer. Ordinal multiple regression showed that indoor living conditions, residence location, living routine, and habit and personal health impacts were significantly correlated with UGS visits. Interdependence between push and pull factors was detected, demonstrating that intrinsic UGS environmental conditions could constrain UGS visits despite the motivations of push factors. The results indicated the need to improve the microclimate-regulating function in UGS. It could be achieved mainly by optimizing the nature-based design to promote UGS as an adaptive measure to combat the thermal stress brought by climate change. The findings yielded hints to shape visiting habits and suggestions to improve UGS management

    Association of adverse perinatal outcomes of intrahepatic cholestasis of pregnancy with biochemical markers

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    __Background__ Intrahepatic cholestasis of pregnancy is associated with adverse perinatal outcomes, but the association with the concentration of specific biochemical markers is unclear. We aimed to quantify the adverse perinatal effects of intrahepatic cholestasis of pregnancy in women with increased serum bile acid concentrations and determine whether elevated bile acid concentrations were associated with the risk of stillbirth and preterm birth. __Methods__ We did a systematic review by searching PubMed, Web of Science, and Embase databases for studies published from database inception to June 1, 2018, reporting perinatal outcomes for women with intrahepatic cholestasis of pregnancy when serum bile acid concentrations were available. Inclusion criteria were studies defining intrahepatic cholestasis of pregnancy based upon pruritus and elevated serum bile acid concentrations, with or without raised liver aminotransferase concentrations. Eligible studies were case-control, cohort, and populationbased studies, and randomised controlled trials, with at least 30 participants, and that reported bile acid concentrations and perinatal outcomes. Studies at potential higher risk of reporter bias were excluded, including case reports, studies not comprising cohorts, or successive cases seen in a unit; we also excluded studies with high risk of bias from groups selected (eg, a subgroup of babies with poor outcomes were explicitly excluded), conference abstracts, and Letters to the Editor without clear peer review. We also included unpublished data from two UK hospitals. We did a random effects meta-analysis to determine risk of adverse perinatal outcomes. Aggregate data for maternal and perinatal outcomes were extracted from case-control studies, and individual patient data (IPD) were requested from study authors for all types of study (as no control group was required for the IPD analysis) to assess associations between biochemical markers and adverse outcomes using logistic and stepwise logistic regression. This study is registered with PROSPERO, number CRD42017069134. __Findings__ We assessed 109 full-text articles, of which 23 studies were eligible for the aggregate data meta-analysis (5557 intrahepatic cholestasis of pregnancy cases and 165136 controls), and 27 provided IPD (5269 intrahepatic cholestasis of pregnancy cases). Stillbirth occurred in 45 (0·91%) of 4936 intrahepatic cholestasis of pregnancy cases and 519 (0·32%) of 163947 control pregnancies (odds ratio [OR] 1·46 [95% CI 0·73–2·89]

    Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC

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    A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions

    Measurement of the correlation between flow harmonics of different order in lead-lead collisions at √sNN = 2.76 TeV with the ATLAS detector

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    Correlations between the elliptic or triangular flow coefficients vm (m=2 or 3) and other flow harmonics vn (n=2 to 5) are measured using √sNN=2.76 TeV Pb+Pb collision data collected in 2010 by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 7 ÎŒb−1. The vm−vn correlations are measured in midrapidity as a function of centrality, and, for events within the same centrality interval, as a function of event ellipticity or triangularity defined in a forward rapidity region. For events within the same centrality interval, v3 is found to be anticorrelated with v2 and this anticorrelation is consistent with similar anticorrelations between the corresponding eccentricities, Δ2 and Δ3. However, it is observed that v4 increases strongly with v2, and v5 increases strongly with both v2 and v3. The trend and strength of the vm−vn correlations for n=4 and 5 are found to disagree with Δm−Δn correlations predicted by initial-geometry models. Instead, these correlations are found to be consistent with the combined effects of a linear contribution to vn and a nonlinear term that is a function of v22 or of v2v3, as predicted by hydrodynamic models. A simple two-component fit is used to separate these two contributions. The extracted linear and nonlinear contributions to v4 and v5 are found to be consistent with previously measured event-plane correlations

    The performance of the jet trigger for the ATLAS detector during 2011 data taking

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    The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction

    Search for vectorlike B quarks in events with one isolated lepton, missing transverse momentum, and jets at √s = 8 TeV with the ATLAS detector

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    A search has been performed for pair production of heavy vectorlike down-type (B) quarks. The analysis explores the lepton-plus-jets final state, characterized by events with one isolated charged lepton (electron or muon), significant missing transverse momentum, and multiple jets. One or more jets are required to be tagged as arising from b quarks, and at least one pair of jets must be tagged as arising from the hadronic decay of an electroweak boson. The analysis uses the full data sample of pp collisions recorded in 2012 by the ATLAS detector at the LHC, operating at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb −1 . No significant excess of events is observed above the expected background. Limits are set on vectorlike B production, as a function of the B branching ratios, assuming the allowable decay modes are B → Wt/Zb/Hb. In the chiral limit with a branching ratio of 100% for the decay B → Wt, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 810 GeV (760 GeV). In the case where the vectorlike B quark has branching ratio values corresponding to those of an SU(2) singlet state, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 640 GeV (505 GeV). The same analysis, when used to investigate pair production of a colored, charge 5/3 exotic fermion T 5/3 , with subsequent decay T 5/3 → Wt, sets an observed (expected) 95% C.L. lower limit on the T 5/3 mass of 840 GeV (780 GeV)

    Measurement of jet charge in dijet events from √s = 8  TeV pp collisions with the ATLAS detector

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    The momentum-weighted sum of the charges of tracks associated to a jet is sensitive to the charge of the initiating quark or gluon. This paper presents a measurement of the distribution of momentum-weighted sums, called jet charge, in dijet events using 20.3 fb−Âč of data recorded with the ATLAS detector at √s = 8 TeV in pp collisions at the LHC. The jet charge distribution is unfolded to remove distortions from detector effects and the resulting particle-level distribution is compared with several models. The pT dependence of the jet charge distribution average and standard deviation are compared to predictions obtained with several leading-order and next-to-leading-order parton distribution functions. The data are also compared to different Monte Carlo simulations of QCD dijet production using various settings of the free parameters within these models. The chosen value of the strong coupling constant used to calculate gluon radiation is found to have a significant impact on the predicted jet charge. There is evidence for a pT dependence of the jet charge distribution for a given jet flavor. In agreement with perturbative QCD predictions, the data show that the average jet charge of quark-initiated jets decreases in magnitude as the energy of the jet increases

    ARDD 2020: from aging mechanisms to interventions

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    Aging is emerging as a druggable target with growing interest from academia, industry and investors. New technologies such as artificial intelligence and advanced screening techniques, as well as a strong influence from the industry sector may lead to novel discoveries to treat age-related diseases. The present review summarizes presentations from the 7th Annual Aging Research and Drug Discovery (ARDD) meeting, held online on the 1st to 4th of September 2020. The meeting covered topics related to new methodologies to study aging, knowledge about basic mechanisms of longevity, latest interventional strategies to target the aging process as well as discussions about the impact of aging research on society and economy. More than 2000 participants and 65 speakers joined the meeting and we already look forward to an even larger meeting next year. Please mark your calendars for the 8th ARDD meeting that is scheduled for the 31st of August to 3rd of September, 2021, at Columbia University, USA
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