1,655 research outputs found

    Polarization States in B -> rho K* and New Physics

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    The standard-model explanations of the anomalously-large transverse polarization fraction fT in B -> phi K* can be tested by measuring the polarizations of the two decays B+ -> rho+ K*0 and B+ -> rho0 K*+. For the scenario in which the transverse polarizations of both B -> rho K* decays are predicted to be large, we derive a simple relation between the fT's of these decays. If this relation is not confirmed experimentally, this would yield an unambiguous signal for new physics. The new-physics operators which can account for the discrepancy in B -> pi K decays will also contribute to the polarization states of B -> rho K*. We compute these contributions and show that there are only two operators which can simultaneously account for the present B -> pi K and B -> rho K* data. If the new physics obeys an approximate U-spin symmetry, the B -> phi K* measurements can also be explained.Comment: 20 pages, latex, no figures. Minor changes to references and Table 1. Minor modification of terms; more complete description of triple-product asymmetry. Analysis and conclusions unchange

    (E)-1-([1,1′-Biphen­yl]-4-yl)-2-(1,3,3-tri­methylindolin-2-yl­idene)ethanone

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    The title compound, C25H23NO, consists of a biphenyl-4-carbonyl unit attached to an exocyclic double bond group at position 2 of an indole unit, which presents methyl groups as substituents at positions 1 and 3. The mol­ecular conformation is s-cis with an E configuration, supported by weak intra­molecular C—H⋯O contacts involving the methyl groups and the carbonyl function. The rings of the biphenyl group are twisted by 37.13 (5)°. In the crystal, C—H⋯O and C—H⋯π inter­actions link the molecules

    The 21 cm Signature of Shock Heated and Diffuse Cosmic String Wakes

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    The analysis of the 21 cm signature of cosmic string wakes is extended in several ways. First we consider the constraints on GμG\mu from the absorption signal of shock heated wakes laid down much later than matter radiation equality. Secondly we analyze the signal of diffuse wake, that is those wakes in which there is a baryon overdensity but which have not shock heated. Finally we compare the size of these signals compared to the expected thermal noise per pixel which dominates over the background cosmic gas brightness temperature and find that the cosmic string signal will exceed the thermal noise of an individual pixel in the Square Kilometre Array for string tensions Gμ>2.5×10−8G\mu > 2.5 \times 10^{-8}.Comment: 10 pages, 4 figures, Appendix added, version published in JCA

    Structural mechanism for regulation of the AAA-ATPases RUVBL1-RUVBL2 in the R2TP co-chaperone revealed by cryo-EM

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    The human R2TP complex (RUVBL1-RUVBL2-RPAP3-PIH1D1) is an HSP90 co-chaperone required for the maturation of several essential multiprotein complexes, including RNA polymerase II, small nucleolar ribonucleoproteins, and PIKK complexes such as mTORC1 and ATR-ATRIP. RUVBL1-RUVBL2 AAA-ATPases are also primary components of other essential complexes such as INO80 and Tip60 remodelers. Despite recent efforts, the molecular mechanisms regulating RUVBL1-RUVBL2 in these complexes remain elusive. Here, we report cryo-EM structures of R2TP and show how access to the nucleotide-binding site of RUVBL2 is coupled to binding of the client recruitment component of R2TP (PIH1D1) to its DII domain. This interaction induces conformational rearrangements that lead to the destabilization of an N-terminal segment of RUVBL2 that acts as a gatekeeper to nucleotide exchange. This mechanism couples protein-induced motions of the DII domains with accessibility of the nucleotide-binding site in RUVBL1-RUVBL2, and it is likely a general mechanism shared with other RUVBL1-RUVBL2-containing complexes

    Metodología para el diseño de enlaces satelitales

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    En este artículo se presenta una breve reseña que intenta guiar al lector en la teoría básica de una telecomunicación satelital, exponiendo sus conceptos principales, los parámetros más relevantes y las ecuaciones generales a partir de las cuales se puede describir el enlace de comunicación; además de algunas consideraciones relevantes para el cálculo de las características del enlace como la potencia irradiada, ubicación geográfica, el tipo de modulación, el BER, etc. Luego se desarrolla un ejemplo de diseño de un enlace de comunicación satelital entre dos puntos geográficos distantes con descripciones concisas y procedimientos específicos

    Told through the wine: a liquid chromatography-mass spectrometry interplatform comparison reveals the influence of the global approach on the final annotated metabolites in non-targeted metabolomics

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    This work focuses on the influence of the selected LC-HRMS platform on the final annotated compounds in non-targeted metabolomics. Two platforms that differed in columns, mobile phases, gradients, chromatographs, mass spectrometers (Orbitrap [Platform#1] and Q-TOF [Platform#2]), data processing and marker selection protocols were compared. A total of 42 wines samples from three different protected denomination of origin (PDO) were analyzed. At the feature level, good (O)PLS-DA models were obtained for both platforms (Q2[Platform#1]=0.89, 0.83 and 0.72; Q2[Platform#2]=0.86, 0.86 and 0.77 for Penedes, Ribera del Duero and Rioja wines respectively) with 100% correctly classified samples in all cases. At the annotated metabolite level, platforms proposed 9 and 8 annotated metabolites respectively which were identified by matching standards or the MS/MS spectra of the compound. At this stage, none of the suggested metabolites was coincident between platforms. When screened on the raw data, 6 and 5 of these compounds were detected on the other platform with a similar trend. Some of the detected metabolites showed complimentary information when integrated on biological pathways. Through the use of some examples at the annotated metabolite level, possible explanations of this initial divergence on the results are presented. This work shows the complications that may arise on the comparison of non-targeted metabolomics platforms even when metabolite focused approaches are used in the identificatio

    Adenovirus-36 Seropositivity and Its Relation with Obesity and Metabolic Profile in Children

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    The human adenovirus 36 (Ad-36) is causally and correlatively associated in animals and humans, respectively, with increased adiposity and altered metabolic profile. In previous studies, the relationship between Ad-36 seropositivity with obesity was established in adults and children. We evaluated the association of positive antibodies to Ad-36 with obesity and metabolic profile in Mexican children. Seventy-five children with normal-weight and 82 with obesity were studied in this research. All children had a clinic assessment which included weight, height, body circumferences, and skinfold thickness. Laboratory analyzes included triglycerides, total cholesterol, high-density lipoprotein, low-density lipoprotein, and glucose and insulin levels. An enzyme-linked immunosorbent assay (ELISA) was used to determine the antibodies to Ad-36 in the serum samples. The overall Ad-36 seroprevalence was 73.9%. Ad-36 seropositivity had a higher prevalence in obese children than in normal weight group (58.6 versus 41.4%, P=0.007). Ad-36 seropositivity was associated with obesity (OR=2.66, P=0.01) and high-density lipoprotein <40 mg/dL (OR=2.85, P=0.03). The Ad-36 seropositive group had greater risk of 4 metabolic abnormalities compared with those children without none alteration. In summary, Ad-36 seropositivity was associated with obesity and low HDL-c levels in the sample of children studied

    La gestión de tecnologías emergentes en el ámbito universitario

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    El carácter emergente de algunas tecnologías hace que tengan un alto grado de incertidumbre, lo que a su vez conlleva particularidades en su manejo respecto a las tecnologías maduras. El objetivo de este artículo es analizar la gestión de tecnologías emergentes en el contexto internacional, con énfasis en el ámbito universitario; para ello, se aplican técnicas cienciométricas a información obtenida de bases de datos de artículos científicos y técnicos. Así mismo, se examina el papel de las universidades, para lo cual se hace un análisis comparativo de algunos casos de reconocido impacto en el nivel mundial. Entre los resultados obtenidos está la identificación de áreas relevantes como la nanotecnología y la telefonía móvil, y la caracterización del manejo de las tecnologías emergentes en las universidades seleccionadas. Esto da la base para plantear algunas conclusiones y consideraciones, como la necesidad de que las universidades colombianas lideren el desarrollo tecnológico en el país promoviendo su impacto en el sector productivo, para lo cual requieren consolidar estructuras y políticas claras en el tema, así como una cultura en propiedad intelectual.Some technologies considered emerging, have high uncertainly and particularities in their management respect to mature technologies. The aim of this paper is to analyze the management of emerging technologies, focused on the university context. For this purpose, scientometric techniques are applied to information from databases of technical papers. The role of universities is studied through a comparative analysis of some internationally recognized cases. As a result, relevant areas were identified, as nanotechnology and mobile communications, and management of emerging technologies in selected cases was characterized. These results are the base to formulate some conclusions and proposals for Colombian universities: They must lead technological development in the country through their impact on the industrial sectors, but these institutions need structures and clear policies, as well as an Intellectual Property culture
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