441 research outputs found
Probing the gluon density of the proton in the exclusive photoproduction of vector mesons at the LHC: A phenomenological analysis
The current uncertainty on the gluon density extracted from the global parton
analysis is large in the kinematical range of small values of the Bjorken -
variable and low values of the hard scale . An alternative to reduces this
uncertainty is the analysis of the exclusive vector meson photoproduction in
photon - hadron and hadron - hadron collisions. This process offers a unique
opportunity to constrain the gluon density of the proton, since its cross
section is proportional to the gluon density squared. In this paper we consider
current parametrizations for the gluon distribution and estimate the exclusive
vector meson photoproduction cross section at HERA and LHC using the leading
logarithmic formalism. We perform a fit of the normalization of the
cross section and the value of the hard scale for the process and demonstrate
that the current LHCb experimental data are better described by models that
assume a slow increasing of the gluon distribution at small - and low
.Comment: 8 pages, 6 figures, 1 table. Version published in European Physical
Journal
Questões crÃticas em validação de métodos analÃticos.
Experimentação e testes de hipóteses; Dificuldades em treinamentos; NÃvel de validação necessário e responsabilidade cabÃveis; Dificuldades comuns; Incerteza; Valor verdadeiro; Realização dos experimentos de validação; Número de repetições; Faixa de trabalho; Valores aberrantes; Experimentos de precisão (estudos colaborativos); Amostragem; Incerteza de amostragem; Verificação de conformidade; CrÃtica de validação; Conclusões
Projeto de treinamento em validação intra e interlaboratorial de métodos analÃticos e seu alcance.
On the Structural Behavior of Composite Beams Using Cold-formed Shapes
Cold-formed shapes have been increasingly employed in the construction of small multiple-floored buildings in Brazil, because wide flange shapes required to meet the demand are unavailable on the Brazilian market. Because existing codes fail to cover the design of composite beams constituted of cold-formed shapes, Brazilian design engineers have usually disregarded the contribution of the slab or have adopted improvised calculations that may to lead to unsafe results. The structural behavior of composite beams, constituted of cold-formed double channel shapes and connected to the concrete slab by means of shear connectors that were also cold-formed, was investigated experimentally. Simply supported beams were tested in which the degree of connection (number of connectors) and the type ofload (concentrated or distributed load) were varied. The results were then compared to those obtained through classic theoretical models of composite beam design, which supplied relevant conclusions for the design of these elements
Cold-formed Shear Connectors for Composite Constructions
Construction employing composite steel-concrete structures has been increasingly applied in building and bridge structures, and solutions involving cold-formed profiles have recently appeared which, in many cases, have resulted in reduced costs. Because constructions using composite steel-concrete structures, involving cold-formed profiles, are not covered by current Brazilian Codes, it is necessary to investigate the issue. This paper, therefore, presents the results of an experimental analysis (24 push-out tests) made for two types of connectors: U-profile and angle, with two plate thicknesses: 2.65 mm and 4.76 mm, evaluating their strength and their load-slip behavior. The tests were performed on test specimens adapted to those proposed by the British Standard BS 5400 - part 5 and by EUROCODE 3
IFNAR1 Controls Progression to Cerebral Malaria in Children and CD8+ T Cell Brain Pathology in Plasmodium berghei-Infected Mice
This publication hasn't any creative commons license associated.
There is no public supplementary material available.Development of cerebral malaria (CM), a severe and fatal form of clinical Plasmodium falciparum infection, results from a damaging cascade of vascular, inflammatory, and immunological host responses that leads to brain injury. Progression to CM can be modified by host genetic factors. Our case-control study in Angolan children aimed at highlighting the role of IFN (α, β) receptor 1 (IFNAR1) in progression to CM. We report a robust association between IFNAR1 and CM protection, as well as detailed studies showing analogous protection from experimental CM in Ifnar1(-/-) mice infected with P. berghei ANKA. We developed a novel cell-transfer protocol that enables spleen cell priming in the absence of disease. This led to the discovery that IFNAR1 expression in CD8(+) T cells is crucial and can abrogate resistance to experimental CM in Ifnar1(-/-) mice. Splenic CD8(+) T cells from Ifnar1(-/-) mice are functionally activated upon infection, yet are unable to mediate experimental CM development within the brain tissue. Our findings prove that IFNAR1 signaling unleashes CD8(+) T cell effector capacity, which is vital for CM, and raises the hypothesis that the cohesive role of IFNAR1 in both human and mouse CM operates through CD8(+) T cell triggering.FCT fellowships: (SFRH/BD/33564/2008, SFRH/BPD/29354/2006)
Detecção de valores aberrantes em alguns experimentos interlaboratoriais para alimentos.
Valores aberrantes são grande preocupação em laboratórios de alimentos, até pela heterogeneidade de muitas matrizes, e, embora haja diversos testes de hipóteses para identificá-los, faltam informações detalhadas sobre seus resultados. Gráficos, como desenhos esquemáticos, ramo-e-folhas e outros, não têm sido vistos em laboratórios com esse objetivo. Interlaboratoriais da literatura em alimentos foram revistos e tais gráficos foram empregados junto aos testes de Dixon, Grubbs e Hampel, além do escore Zr. Pôde-se notar como os resultados desses métodos podem apresentar discordâncias, tanto entre os gráficos como entre os resultados numéricos, e entre os últimos e os primeiros. Dentre os gráficos empregados, além dos desenhos esquemáticos, os ramo-e-folhas trouxeram boa visualização de valores aberrantes. Nas técnicas numéricas, o escore Zr apontou o maior número de valores aberrantes potenciais e o teste de Hampel se mostrou mais adequado. Houve conformidade entre os resultados desta pesquisa e os de um dos quatro interlaboratoriais revisitados, enquanto foram observadas divergências nos demais. Sugere-se o emprego, quando possÃvel, dos modelos de delineamentos ao estudar os experimentos e atenção aos casos com mais de 1% de valores aberrantes
Consumo e digestibilidade aparente da matéria seca, da proteÃna bruta e da energia de silagens de quatro genotipos de sorgo (Sorghum bicolor (L.) Moench) por ovinos.
The nitrogen balance, the consumption and the apparent digestibility of dry matter, crude protein and the energy of the silages of four genotypes of sorghum were evaluated. The consumption of dry matter and crude energy did not differ among the hibrids. The largest apparent digestibility of dry matter, crude energy and the consumption of digestible dry matter and energy, were observed for BR601 genotype. The largest consumption of crude protein, was observed for BR700 and the smallest for AG2002 genotypes (P<0.05). The largest apparent digestibility of protein was observed for BR601 and the smallest one for BR701 (P<0.05) genotype. The consumption of digestible protein was larger for BR601 and BR700. All treatments showed positive nitrogen balance and did not differ among them
Worldwide research trends on the use of chemical-mechanical caries removal products over the years: a critical review
[EN] Background Chemical¿mechanical caries removal (CMCR) products are in constant evolution and were recommended
during the COVID-19 pandemic as substitutes for conventional caries removal.
Aim Characterize the worldwide scientifc literature about CMCR products, over the years, by means of a critical review.
Design Electronic search was performed on Medline/PubMed, Scopus, Web of Science, Cochrane Library, Lilacs, and
Embase up to November 2020. Year, journal, country of authors, and type of study were the data extracted from the retrieved
studies. Additional data of the clinical studies and systematic reviews were investigated.
Results 2221 records were identifed, 397 selected. 2011¿2020 period concentrates higher number of publications (n=169),
in the Journal of Dental Research (n=51), developed in Brazil (n=45) and India (n=44). Most studies were in vitro (n=211)
and clinical trials (n=101). Carisolv¿ (n=48) and Papacarie Duo Gel¿ (n=33) were the most used products, prescript in
isolated usage (n=101), and compared with drills (n=77). CMCR were more studied in primary teeth (n=78), receiving
glass ionomer cement (GIC) (n=51) as restorative material. The most evaluated outcomes were time spent (n=48) and pain
(n=41). Clinical application of CMCR takes more time than other techniques, but can also reduce patient anxiety, pain,
and need for anesthesia.
Conclusion In vitro and clinical studies with CMCR products have been increasing, mostly carried out in developing countries, evaluating Carisolv¿ and Papacarie Duo Gel¿. Clinical studies tend to evaluate the time spent and pain compared to
drills for removing caries in primary teeth, posteriorly restored with GIC. CMCR clinical application reduces anxiety, pain,
and need for anesthesia, despite increase treatments¿ time.This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brazil (CAPES) -Finance code 001, and Fundacao Carlos Chagas de Amparo a Pesquisa no Estado do Rio de Janeiro (FAPERJ)-Finance code E-26/202.766/2019, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) -Finance code 401058/2016-6 -for the VantagePointT software. This study is part of the Master's thesis of the primary author.Souza, TF.; Martins, ML.; Magno, MB.; Vicente Gomila, JM.; Fonseca-Goncalves, A.; Maia, LC. (2022). Worldwide research trends on the use of chemical-mechanical caries removal products over the years: a critical review. European Archives of Paediatric Dentistry. 23(6):869-883. https://doi.org/10.1007/s40368-022-00726-686988323
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