200 research outputs found

    Pleba\'nski-Demia\'nski-like solutions in metric-affine gravity

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    We consider a (non--Riemannian) metric--affine gravity theory, in particular its nonmetricity--torsion sector ``isomorphic'' to the Einstein--Maxwell theory. We map certain Einstein--Maxwell electrovacuum solutions to it, namely the Pleba\'nski--Demia\'nski class of Petrov type D metrics.Comment: 12 pages of a LaTeX-fil

    Corrosion resistance of protective coatings against molten nitrate salts for thermal energy storage and their environmental impact in CSP technology

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    Sol-gel ZrO2–3%molY2O3 coating deposited by means of a dip-coating application on P91 steel was statically tested at 500 °C in contact with Solar Salt (60% wt.% NaNO3/40 wt.% of KNO3) for 1000 h. This work assessed the behaviour of the coated P91 steel both from a technical and environmental point of view. Both studies were compared to those obtained with AISI 304 steel, which is currently used in commercial CSP plants. In terms of corrosion evaluation, the behaviour of the coated P91 was directly comparable to that of the uncoated AISI 304, SEM micrographs revealing the better behaviour of coated samples and the maintenance of a compact coating layer, with a thickness ranging between 1 and 1.4â€ŻÎŒm. Furthermore, environmental analyses revealed the environmental benefits obtained by using lower Cr-Ni content steel coated with ZrO2–Y2O3 compared to AISI 304 alloy, since this coating had a negligible environmental impact (its influence is below 0.03%). Thus, the proposed scenario seems to be workable in CSP high-temperature applications both from technical and environmental points of view. The linked technical-environmental quantification provided in this paper highlights the importance of considering the whole assessment when conducting material selection for CSP applications.Publicad

    “They don’t trust us; they don’t care if we’re attacked”: trust and risk perception in Mexican journalism

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    Drawing from 93 semi-structured, in-person interviews with journalists from 23 states, this article analyzes the relation between trust and risk perception in Mexican journalism. It focuses on how Mexican journalists perceive and experience public trust placed in them as social actors, and how it influences their willingness or reluctance to assume the risks associated with reporting on corruption and drug-trafficking in a country marked by anti-press violence. The findings challenge previous studies as they show that journalists from all regions of the country –even in the so-called safe states– are fearful, even when they have not been victims of threats, beatings or kidnappings. Also, it explains that the connection between institutions and journalism makes news workers feel unprotected and unaccompanied. As a result, they accept self-censorship and even express a willingness to resign. Thus, this article surpasses the social, spatial and temporal delimitations of risk, by arguing that distrust in journalists increases the dangers they face

    Metronomic Cyclophosphamide and Methotrexate Chemotherapy Combined with 1E10 Anti-Idiotype Vaccine in Metastatic Breast Cancer

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    The use of low doses of cytotoxic agents continuously for prolonged periods is an alternative for the treatment of patients with metastatic breast cancer who have developed resistance to conventional chemotherapy. The combination of metronomic chemotherapy with therapeutic vaccines might increase the efficacy of the treatment. Twenty one patients with metastatic breast cancer in progression and a Karnosky index ≄60%, were treated with metronomic chemotherapy (50 mg of cyclophospamide orally daily and 2.5 mg of methotrexate orally bi-daily), in combination with five bi-weekly subcutaneous injections of 1 mg of aluminum hydroxide-precipitated 1E10 anti-idiotype MAb (1E10-Alum), followed by reimmunizations every 28 days. Five patients achieved objective response, eight showed stable disease and eight had disease progression. Median time to progression was 9,8 months, while median overall survival time was 12,93 months. The median duration of the response (CR+PR+SD) was 18,43 months (12,20–24,10 months), being higher than 12 months in 76,9% of the patients. Overall toxicity was generally mild. Metronomic chemotherapy combined with 1E10-Alum vaccine immunotherapy might be a useful therapeutic option for the treatment of metastatic breast cancer due to its potential impact on survival and patient quality of live, low toxicity and advantages of the administration

    Viviendas paradigmĂĄticas en Manta: comprendidas entre los años 1960 – 1980

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    The Reading of the architecture of a city permits to understand features about its history, evolution, and development. Especially, if that place contains architectural works of a paradigmatic nature that strengthen and contribute to the identity of its collective. This text aims to demonstrate the architectural value of the house "Cevallos" wich shows the important role they play as cultural artifacts, as well as the technical innovation they represent, so the memory of these works and their authors is not lost. To this end, the research was carried out at three levels: exploratory, descriptive, and deductive. The methodology applied includes descriptive, critical, and phenomenological analysis based on studies related to this topic so that they oriented to the optimal analysis of architectural projects that represent culture and qualify as paradigmatic. As a result of the study it was found that the canton of Manta has architectural works of a paradigmatic nature, the 56% of the respondents were unaware of their existence influencing them in a negative way, leaving them in oblivion and with them a sample of identity of the place, in response to the problem a matrix is proposed for the qualification of a paradigmatic architecture.La lectura de la arquitectura de una ciudad permite entender rasgos de su historia, evoluciĂłn y desarrollo. Especialmente si el lugar cuenta con obras de carĂĄcter paradigmĂĄtico que afianza y aportan a la identidad de su colectivo. Este texto es la sintesis de un estudio, donde se analizaron dos viviendas construidas en Manta-Ecuador entre los años 1960 – 1980, para efectos al presente articulo, se opto por citar solo una. Se pretende demostrar el valor arquitectĂłnico de la vivienda “Cevallos”, que evidencia su funciĂłn como artefacto cultural, asĂ­ como la innovaciĂłn tĂ©cnica que representa, de manera que la memoria de esta obra y su autor no se pierda. Se llevĂł a cabo la investigaciĂłn en tres niveles: exploratorio, descriptivo y deductivo. La metodologĂ­a aplicada incluye anĂĄlisis descriptivo, crĂ­tico y fenomenolĂłgico en base a estudios afines al tema. Como resultado, se comprobĂł que Manta cuenta con obras arquitectĂłnicas de carĂĄcter paradigmĂĄtica, el problema es la carencia de su conocimiento, el 56% de los encuestados desconocĂ­an de su existencia influyendo de manera negativa, dejĂĄndolas en el olvido y consigo una muestra de identidad del lugar, en respuesta a la problemĂĄtica se plantea una matriz para la calificaciĂłn de una arquitectura paradigmĂĄtica

    Noncommutative Quantum Cosmology

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    We propose a model for noncommutative quantum cosmology by means of a deformation of minisuperspace. For the Kantowski-Sachs metric we are able to find the exact wave function. We construct wave packets and show that new quantum states that ``compete'' to be the most probable state appear, in clear contrast with the commutative case. A tunneling process could be possible among these states.Comment: 5 pages, 5 figures, revtex4 file, major style changes, to be published in PR

    Hepatic galectin-3 is associated with lipid droplet area in non-alcoholic steatohepatitis in a new swine model

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    Non-alcoholic fatty liver disease (NAFLD) is currently a growing epidemic disease that can lead to cirrhosis and hepatic cancer when it evolves into non-alcoholic steatohepatitis (NASH), a gap not well understood. To characterize this disease, pigs, considered to be one of the most similar to human experimental animal models, were used. To date, all swine-based settings have been carried out using rare predisposed breeds or long-term experiments. Herein, we fully describe a new experimental swine model for initial and reversible NASH using cross-bred animals fed on a high saturated fat, fructose, cholesterol, cholate, choline and methionine-deficient diet. To gain insight into the hepatic transcriptome that undergoes steatosis and steatohepatitis, we used RNA sequencing. This process significantly up-regulated 976 and down-regulated 209 genes mainly involved in cellular processes. Gene expression changes of 22 selected transcripts were verified by RT-qPCR. Lipid droplet area was positively associated with CD68, GPNMB, LGALS3, SLC51B and SPP1, and negatively with SQLE expressions. When these genes were tested in a second experiment of NASH reversion, LGALS3, SLC51B and SPP1 significantly decreased their expression. However, only LGALS3 was associated with lipid droplet areas. Our results suggest a role for LGALS3 in the transition of NAFLD to NASH

    Genomic Characterization of Host Factors Related to SARS-CoV-2 Infection in People with Dementia and Control Populations: The GR@ACE/DEGESCO Study

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    Emerging studies have suggested several chromosomal regions as potential host genetic factors involved in the susceptibility to SARS-CoV-2 infection and disease outcome. We nested a COVID-19 genome-wide association study using the GR@ACE/DEGESCO study, searching for susceptibility factors associated with COVID-19 disease. To this end, we compared 221 COVID-19 confirmed cases with 17,035 individuals in whom the COVID-19 disease status was unknown. Then, we performed a meta-analysis with the publicly available data from the COVID-19 Host Genetics Initiative. Because the APOE locus has been suggested as a potential modifier of COVID-19 disease, we added sensitivity analyses stratifying by dementia status or by disease severity. We confirmed the existence of the 3p21.31 region (LZTFL1, SLC6A20) implicated in the susceptibility to SARS-CoV-2 infection and TYK2 gene might be involved in COVID-19 severity. Nevertheless, no statistically significant association was observed in the COVID-19 fatal outcome or in the stratified analyses (dementia-only and non-dementia strata) for the APOE locus not supporting its involvement in SARS-CoV-2 pathobiology or COVID-19 prognosis

    Osteocyte deficiency in hip fractures

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    Osteocytes play a central role in the regulation of bone remodeling. The aim of this study was to explore osteocyte function, and particularly the expression of SOST, a Wnt inhibitor, in patients with hip fractures. Serum sclerostin levels were measured by ELISA. The expression of several osteocytic genes was studied by quantitative PCR in trabecular samples of the femoral head of patients with hip fractures, hip osteoarthritis and control subjects. The presence of sclerostin protein and activated caspase 3 was revealed by immunostaining. There were no significant differences in serum sclerostin between the three groups. Patients with fractures have fewer lacunae occupied by osteocytes (60 ± 5% vs. 64 ± 6% in control subjects, P = 0.014) and higher numbers of osteocytes expressing activated caspase 3, a marker of apoptosis. The proportion of sclerostin-positive lacunae was lower in patients with fractures than in control subjects (34 ± 11% vs. 69 ± 10%, P = 2 × 10(-8)). The proportion of sclerostin-positive osteocytes was also lower in patients. RNA transcripts of SOST, FGF23 and PHEX were also less abundant in fractures than in control bones (P = 0.002, 5 × 10(-6), and 0.04, respectively). On the contrary, in patients with osteoarthritis, there was a decreased expression of SOST and FGF23, without differences in PHEX transcripts or osteocyte numbers. Osteocyte activity is altered in patients with hip fractures, with increased osteocyte apoptosis and reduced osteocyte numbers, as well as decreased transcription of osteocytic genes. Therefore, these results suggest that an osteocyte deficiency may play a role in the propensity to hip fractures
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