623 research outputs found
BIOGEOGRAFIA DOS MANGUEZAIS
Os manguezais sĂŁo ecossistemas localizados entre o mar e a terra firme, ao longo de boa parte dos litorais tropicais e subtropicais de todo o mundo. Este ecossistema, sujeito Ă influĂȘncia de diversos fatores geoecolĂłgicos, em especial Ă hidrodinĂąmica flĂșvio-marinha, possui uma imensa importĂąncia para a biota de diversos ambientes, especialmente para os organismos marinhos, que encontram nele abrigo, local para reprodução, descanso e alimentação. AlĂ©m da variada função ecolĂłgica, os manguezais tambĂ©m sĂŁo importantes para o prĂłprio homem, fornecendo-o recursos alimentares, madeira e proteção contra algumas catĂĄstrofes naturais, como tsunamis. Por outro lado, os manguezais sĂŁo destruĂdos no mundo inteiro pela ação antrĂłpica, que disputa com este ecossistema o valorizado espaço costeiro. Sob esta perspectiva, este trabalho buscou, atravĂ©s de uma revisĂŁo bibliogrĂĄfica bĂĄsica, trazer de maneira sucinta algumas das caracterĂsticas destes ecossistemas costeiros, atravĂ©s de um enfoque biogeogrĂĄfico e ecolĂłgico, bem como a sua importĂąncia ecolĂłgica, benefĂcios que oferece ao homem e as ameaças deste aos manguezais.
Palavras-chave: Manguezais. Biogeografia. Ecologia.
Biogeography of mangroves
Mangroves ecosystems are located between sea and land, along much of coastal tropical and subtropical regions around the world. This ecosystem, subject to the influence of several geoecological factors, the fluvial-marine hydrodinamic particularly, has an immense importance to the biota of the several environments, especially for marine organisms, which find him shelter for reproduction, rest and feeding. Besides the varied ecological function, mangroves are important also for man, providing food resources, wood and some protection against natural disasters, such as tsunamis. Furthermore, the mangroves are destroyed worldwide by human action, that this dispute with the valued ecosystem space on the coastal environment. From this perspective, this study searched, through of the basic review bring some of characteristics of the ecosystem, during a biogeographical and ecological focus as well as their ecological importance, benefits and offers to the man, and the human threats to mangroves.
Key words: Mangroves. Biogeography. Ecology
Thermoelectric and Structural Properties of Sputtered AZO Thin Films with Varying Al Doping Ratios
Nanomaterials can be game-changers in the arena of sustainable energy production because they may enable highly efficient thermoelectric energy conversion and harvesting. For this purpose, doped thin film oxides have been proven to be promising systems for achieving high thermoelectric performances. In this work, the design, realization, and experimental investigation of the thermoelectric properties exhibited by a set of five Al:ZnO thin films with thicknesses of 300 nm and Al doping levels ranging from 2 to 8 at.% are described. Using a multi-technique approach, the main structural and morphological features of the grown thin films are addressed, as well as the electrical and thermoelectrical transport properties. The results show that the samples exhibited a Seebeck coefficient absolute value in the range of 22-33 mu V/K, assuming their maximum doping level was 8 at.%, while the samples' resistivity was decreased below 2 x 10(-3) Ohm center dot cm with a doping level of 3 at.%. The findings shine light on the perspectives of the applications of the metal ZnO thin film technology for thermoelectrics
Explaining the t tbar forward-backward asymmetry without dijet or flavor anomalies
We consider new physics explanations of the anomaly in the top quark
forward-backward asymmetry measured at the Tevatron, in the context of flavor
conserving models. The recently measured LHC dijet distributions strongly
constrain many otherwise viable models. A new scalar particle in the
antitriplet representation of flavor and color can fit the t tbar asymmetry and
cross section data at the Tevatron and avoid both low- and high-energy bounds
from flavor physics and the LHC. An s-channel resonance in uc to uc scattering
at the LHC is predicted to be not far from the current sensitivity. This model
also predicts rich top quark physics for the early LHC from decays of the new
scalar particles. Single production gives t tbar j signatures with high
transverse momentum jet, pair production leads to t tbar j j and 4 jet final
states.Comment: 7 pages, 6 figures; v2: notation clarified, references adde
Investigating Executive Working Memory and Phonological Short-Term Memory in Relation to Fluency and Self-Repair Behavior in L2 Speech
This paper reports the findings of a study investigating the relationship of executive working memory (WM) and phonological short-term memory (PSTM) to fluency and self-repair behavior during an unrehearsed oral task performed by second language (L2) speakers of English at two levels of proficiency, elementary and lower intermediate. Correlational analyses revealed a negative relationship between executive WM and number of pauses in the lower intermediate L2 speakers. However, no reliable association was found in our sample between executive WM or PSTM and self-repair behavior in terms of either frequency or type of self-repair. Taken together, our findings suggest that while executive WM may enhance performance at the conceptualization and formulation stages of the speech production process, self-repair behavior in L2 speakers may depend on factors other than working memory
Audiometric thresholds and auditory processing in children with early malnutrition: a retrospective cohort study
Variation and genetic structure of Melipona quadrifasciata Lepeletier (Hymenoptera, Apidae) populations based on ISSR pattern
For a study of diversity and genetic structuring in Melipona quadrifasciata, 61 colonies were collected in eight locations in the state of Minas Gerais, Brazil. By means of PCR analysis, 119 ISSR bands were obtained, 80 (68%) being polymorphic. He and H B were 0.20 and 0.16, respectively. Two large groups were obtained by the UPGMA method, one formed by individuals from Januåria, Urucuia, Rio Vermelho and Caeté and the other by individuals from São João Del Rei, Barbacena, Ressaquinha and Cristiano Otoni. The Ίst and ΞB values were 0.65 and 0.58, respectively, thereby indicating high population structuring. UPGMA grouping did not reveal genetic structuring of M. quadrifasciata in function of the tergite stripe pattern. The significant correlation between dissimilarity values and geographic distances (r = 0.3998; p < 0.05) implies possible geographic isolation. The genetic differentiation in population grouping was probably the result of an interruption in gene flow, brought about by geographic barriers between mutually close geographical locations. Our results also demonstrate the potential of ISSR markers in the study of Melipona quadrifasciata population structuring, possibly applicable to the studies of other bee species
DNA Barcode Detects High Genetic Structure within Neotropical Bird Species
BACKGROUND: Towards lower latitudes the number of recognized species is not only higher, but also phylogeographic subdivision within species is more pronounced. Moreover, new genetically isolated populations are often described in recent phylogenies of Neotropical birds suggesting that the number of species in the region is underestimated. Previous COI barcoding of Argentinean bird species showed more complex patterns of regional divergence in the Neotropical than in the North American avifauna. METHODS AND FINDINGS: Here we analyzed 1,431 samples from 561 different species to extend the Neotropical bird barcode survey to lower latitudes, and detected even higher geographic structure within species than reported previously. About 93% (520) of the species were identified correctly from their DNA barcodes. The remaining 41 species were not monophyletic in their COI sequences because they shared barcode sequences with closely related species (Nâ=â21) or contained very divergent clusters suggestive of putative new species embedded within the gene tree (Nâ=â20). Deep intraspecific divergences overlapping with among-species differences were detected in 48 species, often with samples from large geographic areas and several including multiple subspecies. This strong population genetic structure often coincided with breaks between different ecoregions or areas of endemism. CONCLUSIONS: The taxonomic uncertainty associated with the high incidence of non-monophyletic species and discovery of putative species obscures studies of historical patterns of species diversification in the Neotropical region. We showed that COI barcodes are a valuable tool to indicate which taxa would benefit from more extensive taxonomic revisions with multilocus approaches. Moreover, our results support hypotheses that the megadiversity of birds in the region is associated with multiple geographic processes starting well before the Quaternary and extending to more recent geological periods
A systematic experimental neuropsychological investigation of the functional integrity of working memory circuits in major depression
Verbal and visuospatial working memory (WM) impairment is a well-documented finding in psychiatric patients suffering from major psychoses such as schizophrenia or bipolar affective disorder. However, in major depression (MDD) the literature on the presence and the extent of WM deficits is inconsistent. The use of a multitude of different WM tasks most of which lack process-specificity may have contributed to these inconsistencies. Eighteen MDD patients and 18 healthy controls matched with regard to age, gender and education were tested using process- and circuit-specific WM tasks for which clear brain-behaviour relationships had been established in prior functional neuroimaging studies. Patients suffering from acute MDD showed a selective impairment in articulatory rehearsal of verbal information in working memory. By contrast, visuospatial WM was unimpaired in this sample. There were no significant correlations between symptom severity and WM performance. These data indicate a dysfunction of a specific verbal WM system in acutely ill patients with MDD. As the observed functional deficit did not correlate with different symptom scores, further, longitudinal studies are required to clarify whether and how this deficit is related to illness acuity and clinical state of MDD patients
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at â s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fbâ1 of â s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at âs = 7 TeV with the ATLAS detector
This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of âs = 7 TeV;{\rm Te}{\rm V}4.6\;{\rm f}{{{\rm b}}^{-1}}{{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}|\eta |\lt 1.9{{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques
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