3,231 research outputs found
Search for the SM Higgs boson in the diphoton decay channel with ATLAS
A search for the Standard Model Higgs boson is presented in the diphoton decay channel. The data used corresponds to an integrated luminosity of 4.9 fb−1 collected with the ATLAS detector at the Large Hadron Collider in protonproton
collisions at a center-of-mass energy of √s = 7TeV
ENERGY CALIBRATION AND OBSERVATION OF THE HIGGS BOSON IN THE DIPHOTON DECAY WITH THE ATLAS EXPERIMENT
ATLAS is one of the four main experiments at the LHC proton-proton accelerator at CERN. This thesis describes two correlated topics: the observation for the Higgs boson in the diphoton channel and the Monte Carlo calibration of electrons and photons.
The Higgs boson is a particle predicted by the Standard Model to explain the mechanism for electroweak symmetry breaking, giving masses to the particles. A particle compatible with the SM Higgs boson has been discovered by the ATLAS and CMS experiments in 2012. If this new boson is the Higgs boson, all fundamental parameters of the SM are known and, for the first time, it is possible to overconstrain the SM at the electroweak scale and to evaluate its validity.
The proton-proton collision datasets used for the diphoton analysis correspond to integrated luminosities of 4.8 fb-1 collected at sqrt(s) = 7 TeV and 13.0 fb-1 collected at sqrt(s) = 8 TeV. The results, for the first time, establish the observation in the diphoton channel alone. The observation has a local significance of 6.1 standard deviations with a measured mass of 126.6 +/- 0.3 (stat) +/- 0.7 (syst) GeV. The fitted number of signal events is found to be 1.80 +/- 0.30 (stat) +0.21 -0.15 (syst) +0.20 -0.14 (theory) times the value predicted by the Standard Model.
Two energy calibrations of electromagnetic particles are presented, a simpler method already used by all the ATLAS analyses and a new method based on a multivariate technique. Single particle Monte Carlo simulations have been used for the optimization. Electrons, unconverted photons and converted photons have been optimized separately. To improve the calibration of converted photons a dedicated correction has been developed. The MVA calibration was developed to introduce more input variables. The improvement is visible in all the energy ranges and in all the pseudorapidity regions and for all the particle hypotheses. The improvement on the Higgs invariant mass resolution in the diphoton channel is about 4%
Annual variation of the malacofauna on two intertidal sandy substrates with rock fragments in southeastern Brazil
The temporal variation in molluscan communities was studied in two intertidal substrates composed of sand and rock fragments <300 mm) in São Sebastião Channel, Brazil. Samples were taken between August 1995 and July 1996 in São Francisco (mainland) and Engenho d'Água (São Sebastião Island) beaches. A pronounced decrease in abundance and diversity of molluscs was associated with changes in the structure of the environment, caused by sea storms in the beginning of the summer (December), and by the increase of waste water discharge in this same period. Areas not subjected to such events showed no evident modifications in mollusc fauna structure during the sampling period, and the small oscillations observed were attributed to population recruitment. Both natural and human factors may be acting together in determining the community organization in these environments, as is also in typical sandy beaches.Estudou-se a variação anual da comunidade de moluscos em dois ambientes entremarés constituídos por areia e fragmentos rochosos <300 mm) no Canal de São Sebastião, Brasil. As amostras foram obtidas mensalmente entre agosto de 1995 e julho de 1996 nas praias São Francisco (continente) e Engenho d'Água (Ilha de São Sebastião). Uma marcante redução na abundância e diversidade foi associada às mudanças estruturais do ambiente, causada por ressacas do mar no início do verão (dezembro), e ao aumento no fluxo de esgotos domésticos neste período. Em áreas onde estes eventos não foram evidentes, não houve grande alteração na composição faunística, e as pequenas oscilações foram atribuídas ao recrutamento de populações numericamente importantes. Ambos os fatores naturais e antrópicos podem estar atuando em conjunto para determinar a organização da comunidade nestes ambientes, tal como ocorre em praias arenosas típicas.141150Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Media use during adolescence: the recommendations of the Italian Pediatric Society.
BACKGROUND: The use of media device, such as smartphone and tablet, is currently increasing, especially among the youngest. Adolescents spend more and more time with their smartphones consulting social media, mainly Facebook, Instagram and Twitter because. Adolescents often feel the necessity to use a media device as a means to construct a social identity and express themselves. For some children, smartphone ownership starts even sooner as young as 7 yrs, according to internet safety experts. MATERIAL AND METHODS: We analyzed the evidence on media use and its consequences in adolescence. RESULTS: In literature, smartphones and tablets use may negatively influences the psychophysical development of the adolescent, such as learning, sleep and sigh. Moreover, obesity, distraction, addiction, cyberbullism and Hikikomori phenomena are described in adolescents who use media device too frequently. The Italian Pediatric Society provide action-oriented recommendations for families and clinicians to avoid negative outcomes. CONCLUSIONS: Both parents and clinicians should be aware of the widespread phenomenon of media device use among adolescents and try to avoid psychophysical consequences on the youngest
Benzodifuran-based fluorescent brighteners: A novel platform for plant cell wall imaging
Herein we designed three novel fluorescent brightening agents based on a benzodifuran skeleton. The compounds are colorless fluorophores emitting in the blue region with an improved water solubility and ability to interact with living cells. A complete understanding of the emission mechanisms was achieved by Density Functional Theory study based on X-ray crystallographic analysis. The fluorescence quantum yields were measured in different solvents and at different pH values. The ability of the different fluorophores to stain cell compartments of plant root samples was tested in water- and glycerol-based solutions. Through fluorescence microscopy technique two probes with a different functionalized branching chain proved to be efficient stains for plant root cell wall. The cationic probe has no harmful effect on plant tissues and is suitable for in vivo fluorescent visualization of plant root cell boundaries. This study sheds light on the potential use of brighteners containing a central benzodifuran core as tools for imaging of fixed and alive plant tissues
Global environmental changes: setting priorities for Latin American coastal habitats.
The definitive version is available at www.blackwell-synergy.comThe Intergovernmental Panel for Climate Change (IPCC) reports that Global Environmental Changes (GEC) are occurring quicker than at any other time over the last 25 million years and impacting upon marine environments (Bellard et al., 2012). There is overwhelming evidence showing that GEC are affecting both the quality and quantity of the goods and services provided by a wide range of marine ecosystems. In order to discuss regional preparedness for global environmental changes, a workshop was held in Ilhabela, Brazil (22- 26 April 2012) entitled "Evaluating the Sensitivity of Central and South American Benthic Communities to Global Environmental Changes" that drew together scientists from ten Latin American and three European countries. © 2013 Blackwell Publishing Ltd
The coast of the Macro metropolis: so far from God and so close to the Devil
O maniqueísmo do título deste artigo antecipa o interesse em aqui analisar as particularidades da polarização da zona costeira em uma escala espacial mais abrangente. Tal análise é feita sob a ótica do ordenamento territorial, da abordagem ecossistêmica e da governança ambiental, e considera os fluxos e dinâmicas incidentes sobre a zona costeira em um contexto de desenvolvimento sustentável. Por meio do estudo de caso da Macrometrópole Paulista (MMP), seu Plano de Ação 2013-2040, e as ações propostas para seu litoral, reconhece-se que, tão perto da metrópole expandida, o litoral macrometropolitano segue longe de um caminho sustentável e socialmente justo. Argumenta-se que o planejamento espacial e a governança deste território demandam uma ampla revisão dos paradigmas que amparam os instrumentos setoriais e multissetoriais de gestão. Novos paradigmas devem considerar diferentes escalas espaciais, como a zona costeira, a zona econômica exclusiva e regiões metropolitanas adjacentes. Nesse sentido, faz-se necessário que o planejamento da MMP considere novos arranjos de governança que abarquem a dinamicidade do território e suas dimensões socioambientais e ecossistêmicas. Devem, ainda, incorporar macroprocessos tanto do ponto de vista administrativo e territorial quanto do ponto de vista socioambiental, incluindo os atores apropriados a essa escala e, em especial, garantindo a participação da sociedade civil.The Manichaeism in the title of article anticipates the interest here to analyze the particularities of coastal zone polarization on a broader spatial scale. Territorial planning, ecosystem-based approach, governance, and considering existing flows and dynamics in the context of sustainable development are the bases of this analysis. Using the case study of the São Paulo Macro Metropolis (SPMM), its 2013-2040 Action Plan, and the proposed actions for its coastline as examples, the fact that being so close to the expanding metropolis, the macro metropolitan coastline is far from a socially, fair and sustainable path is verified. Spatial planning and governance of this territory require a broad revision of the paradigms that support sectoral and multisectoral management instruments. This revision should consider different spatial scales, such as the coastal zone, the exclusive economic zone, and adjacent metropolitan regions. In this sense, it is necessary for SPMM planning to consider new governance arrangements that encompass the dynamics of the territory and its socio-environmental dimensions. It is also necessary to incorporate macro-processes from the administrative, territorial, social, and environmental perspectives, including the stakeholders, according to the management scale, and, particularly, ensuring the participation of civil society
Age reporting for the oldest old in the Brazilian COVID-19 vaccination database: What can we learn from it?
Background: Age misreporting affects population estimates at older ages. In Brazil, every citizen must be registered and show an identity document to vaccinate against COVID-19. This requirement to present proof of age provides a unique opportunity for measuring the oldest-old population using novel administrative data. Objective: To offer critically assessed estimates of the Brazilian population aged 80 and older based on data from the vaccination registration system (VRS). To uncover discrepancies between the number of vaccinated oldest-old people and the projections used to estimate target populations for COVID-19 vaccination. Methods: We calculate data quality indicators based on data from the VRS - namely, 100+/80+ and 90+/80+ population proportions, sex ratios, and the Myers blended index - and compare them to those based on data on target populations from Brazilian censuses and demographic projections, and from Sweden - a country with high-quality data. We also estimate vaccination coverage ratios using population projections adjusted to excess deaths as the denominators. Results: Requiring documentation reduces age heaping, age exaggeration, and sex ratios marginally. However, it cannot solve the problem of the misreporting of birth dates due to the absence of long-standing birth registration systems in Brazil, particularly in the northern and central regions. In addition, we find a mismatch between the projected populations and numbers of vaccinated people across regions. Conclusions: Despite improvements in data quality in Brazil, we are still not confident about the accuracy of age reporting among the oldest old in the less advantaged Brazilian regions. The postponement of the 2020 census reduced the ability of authorities to define the target populations for vaccinations against COVID-19 and other diseases. Contribution: This is the first study to compare population estimates for the oldest old in administrative data and census data in Brazil. Age misreporting resulted in discrepancies that may have compromised the efficacy of the COVID-19 vaccination campaign
Non-linear curve adjustments widen biological interpretation of relative growth analyses of the clam Tivela mactroides (Bivalvia, Veneridae)
Evaluation of relative (allometric) growth provides useful information to understand the development of organisms, as well as to aid in the management of fishery-exploited species. Usually, relative growth analyses use classical models such as the linear equation or the power function (allometric equation). However, these methods do not consider discontinuities in growth and may mask important biological information. As an alternative to overcome poor results and misleading interpretations, recent studies have suggested the use of more complex models, such as non-linear regressions, in conjunction with a model selection approach. Here, we tested differences in the performance of diverse models (simple linear regression, power function, and polynomial models) to assess the relative growth of the trigonal clam Tivela mactroides, an important fishing resource along the South American coast. Regressions were employed to relate parameters of the shell (length (L), width (W), height (H) and weight (SW)) among each other and with soft parts of the organism (dry weight (DW) and ash-free dry weight (ASDW)). Then, model selection was performed using the information theory and multi-model inference approach. The power function was more suitable to describe the relationships involving shell parameters and soft parts weight parameters (i.e., L vs. SW, DW, and AFDW, and SW vs. DW). However, it failed in unveiling changes in the morphometric relationships between shell parameters (i.e., L vs. W and H; W vs. H) over time, which were better described by polynomial functions. Linear models, in turn, were not selected for any relationship. Overall, our results show that more complex models (in this study polynomial functions) can unveil changes in growth related to modifications in environmental features or physiology. Therefore, we suggest that classical and more complex models should be combined in future studies of allometric growth of molluscs
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