300 research outputs found
Identification of critical variables in conventional transformers in distribution networks
Transformers are essential equipment to the operation of electrical power systems, a
failure causes the lack of electricity supply to end-users, affecting the operating indicators of
companies in the distribution sector. The investigation presents an identification of the faults in
transformers through a fishbone diagram, an evaluation of the variables that cause the
identified failure using the cross-impact matrix method and a proposal to improve the
performance. The results will enable a plan to be developed for taking action with monitoring
plans to avoid faults that could put the electrical asset at risk and achieve a better performance
of the distribution network
Experiencias de posgrado sobre computación en la red (cloud computing) con software social
La investigación, desarrollada con estudiantes de un Máster Oficial en Comunicación y Educación en el curso 2011/12, se centró en indagar introspectivamente en el alumnado las ventajas y debilidades de la computación en nube (cloud computing), a través de metodologías activas con mapas conceptuales elaborados con el software Mindomo y, posteriormente, enviadas a un edublog. El trabajo pretendía fomentar su autonomía en el proceso de construcción del conocimiento, mediante estas aplicaciones 2.0, diseñando mapas interactivos sobre computación en nube. Entre los resultados obtenidos, después de la codificación e interpretación de la información, se constata que las aplicaciones Web 2.0 son estrategias metacognitivas activas que orientan la recreación del conocimiento colectivo, permitiendo la categorización de conceptos relevantes y facilitando el pensamiento creativo digital.A research carried out with the collaboration of master students in Communication and Education during the academic year 2011/2012 focusing on advantages and weaknesses of cloud computing through active methodologies using Mindomo’s mind maps and posting them in edublogs. The aim was fostering autonomy in the process of knowledge construction process by means of 2.0 applications and interactive maps. The results show that 2.0 web applications are active metacognitive strategies that support the recreation of collective knowledge and allow the categorization of relevant concepts, facilitating the digital creative thinking
Multi-Etiological Nature of Tuberculosis-Like Lesions in Condemned Pigs at the Slaughterhouse
Tuberculosis-like lesions (TBL) in pigs have been associated with microorganisms other
than mycobacteria. In this work a histopathological and microbiological evaluation of TBL in
pigs is shown. A total of 352 samples belonging to 171 pigs totally condemned at slaughterhouse
due to generalized TBL were sampled and selected for analysis. Pyogranulomatous
(56.2%) and granulomatous lesions (20.2%) were observed in all analysed organs. Most of
the granulomas observed in both lymph nodes and lungs belonged to more advanced
stages of development (stages III and IV) whereas in the liver and the spleen most of lesions
belonged to intermediate stages (stages II and III). Different microorganisms were simultaneously
detected from TBL in the 42.7% of the animals. Mycobacterium tuberculosis complex
(MTC) (38%), coryneform bacteria (40.3%) and streptococci (28.1%) were the main
groups of microorganisms detected after bacteriological analysis, with Trueperella pyogenes
and Streptococcus suis as the most frequently isolated species. Mycobacteria
belonging to MTC were the most frequently detected pathogens in granulomatous and pyogranulomatous
lesions in submandibular lymph nodes (32.7%) and coryneform bacteria
were the microorganisms more frequently isolated from lungs (25.9%) and spleen samples
(37.2%). These results may provide new insights into the pathogenesis and diagnosis of
this pathology. The importance of coryneform bacteria and streptococci in such processes
must be evaluated in future studie
Trencafiles dels llibres antics
L'estil de les trencafiles recopilades és de caràcter típicament mediterrani, estil arrelat a Itàlia , al sud de França i a l'Espanya mediterrània. Els seus trets característics són la simplicitat i el caràcter funcional més que ornamental. Les variacions existents en tot el fons son poc vistoses en general, però, no obstant això, a través dels petits detalls de construcció podem seguir l'evolució que han sofert fins els nostres dies
Synthesis, crystal and molecular structure of methyl[(4-acetamidophenyl)sulfonyl]carbamate, precursor of herbicide Asulam
The methyl[(4-aminophenyl)sulfonyl]carbamate is commercially known as Asulam. It is the most common trade name for a systemic and synergistic herbicide, which is incorporated by the plants through their foliage and roots, and is extensively used against weeds and brackens in the cultivation of gramineous, citric, banana and sugarcane, among others. The industrial procedure for obtaining
this carbamic compound includes the base-catalyzed hydrolysis of the methyl[(4-acetamidophenyl)sulfonyl]carbamate. In this work a simple and conventional method for the synthesis of the Asulam intermediate and the characterization of its crystal and molecular structure utilizing X-Ray Diffraction and IR, NMR 1H and 13C spectroscopic techniques is presented. The synthetic precursor will be
used as substrate of the hydrolytic enzyme in the development of a new biocatalytic preparation of the herbicide Asulam. Therefore, the knowledge of its structure will help not only to define the physical characteristics of its more stable conformation, but also will allow predicting the compatibility between the possible enzymes to be used and the substrate, according to the properties of their catalytic centers. The title compound was synthesized from 4-acetamidophenylsulfonamide and methylchloroformate in the presence of anhydrous K2CO3 and acetone, extracted with ethyl ether and recrystallized from methanol. The studied compound was obtained as crystalline solid in 62% yield. The crystals of intermediate were grown by slow evaporation from methanol solution. They are monoclinic, space group P21/n; a = 8.681(4), b = 8.174(3), c = 17.583(3) Å, ß= 92.40(1) º, Z = 4. The molecular packing shows a bidimensional hydrogen bond network
Nivolumab after selective internal radiation therapy for the treatment of hepatocellular carcinoma: a phase 2, single-arm study
Purpose: To evaluate the safety and efficacy of selective internal radiation therapy (SIRT) in combination with a PD-1 inhibitor in patients with unresectable hepatocellular carcinoma (uHCC) and liver-only disease ineligible for chemoembolization.
Patients and methods: NASIR-HCC is a single-arm, multicenter, open-label, phase 2 trial that recruited from 2017 to 2019 patients who were naïve to immunotherapy and had tumors in the BCLC B2 substage (single or multiple tumors beyond the up-to-7 rule), or unilobar tumors with segmental or lobar portal vein invasion (PVI); no extrahepatic spread; and preserved liver function. Patients received SIRT followed 3 weeks later by nivolumab (240 mg every 2 weeks) for up to 24 doses or until disease progression or unacceptable toxicity. Safety was the primary endpoint. Secondary objectives included objective response rate (ORR), time to progression (TTP), and overall survival (OS).
Results: 42 patients received SIRT (31 BCLC-B2, 11 with PVI) and were followed for a median of 22.2 months. 27 patients discontinued and 1 never received Nivolumab. 41 patients had any-grade adverse events (AE) and 21 had serious AEs (SAE). Treatment-related AEs and SAEs grade 3-4 occurred in 8 and 5 patients, respectively. Using RECIST 1.1 criteria, ORR reported by investigators was 41.5% (95% CI 26.3% to 57.9%). Four patients were downstaged to partial hepatectomy. Median TTP was 8.8 months (95% CI 7.0 to 10.5) and median OS was 20.9 months (95% CI 17.7 to 24.1).
Conclusions: The combination of SIRT and nivolumab has shown an acceptable safety profile and signs of antitumor activity in the treatment of patients with uHCC that were fit for SIRT
The intermediate-redshift galaxy cluster CL 0048-2942. Stellar populations
We present a detailed study of the cluster CL 0048-2942, located at z~0.64,
based on a photometric and spectroscopic catalogue of 54 galaxies in a 5 x 5
square arcmin region centred in that cluster. Of these, 23 galaxies were found
to belong to the cluster. Based on this sample, the line-of-sight velocity
dispersion of the cluster is approximately 680 +- 140 km/s. We have performed
stellar population synthesis in the cluster members as well as in the field
galaxies of the sample and found that there are population gradients in the
cluster with central galaxies hosting mainly intermediate/old populations
whereas galaxies in the cluster outskirts show clearly an increase of younger
populations, meaning that star formation is predominantly taking place in the
outer regions of the cluster. In a general way, field galaxies seem to host
less evolved stellar populations than cluster members. In fact, in terms of
ages, young supergiant stars dominate the spectra of field galaxies whereas
cluster galaxies display a dominant number of old and intermediate age stars.
Following the work of other authors (e.g. Dressler et al. 1999) we have
estimated the percentage of K+A galaxies in our sample and found around 13% in
the cluster and 10% in the field. These values were estimated through means of
a new method, based on stellar population synthesis results, that takes into
account all possible absorption features in the spectrum and thus makes optimal
use of the data.Comment: Accepted by Astronomy & Astrophysics. 24 pages, 10 figures, 10 tables
(figures 3, 4, 5 and tables 1, 3, 4, 5, 6, 7, 8 will be available in
electronic format only in the A&A published version
Full-vector archaeomagnetic dating of a medieval limekiln at Pinilla Del Valle site (Madrid, Spain)
Archaeomagnetic dating based on the full geomagnetic field vector was carried out on a limekiln excavated at Pinilla del Valle archaeological site (Madrid, Spain). The limekiln tradition in this area is largely documented by historical sources for recent centuries but the date of the studied kiln's last use was unknown. The combination of mean archaeomagnetic directional and absolute archaeointensity results shows that the kiln was last used between ad 1296 and 1413, in good agreement with two independent radiocarbon dates. This study provides the first archaeomagnetic evidence that the local limekiln tradition dates back to at least late medieval times. Furthermore, the inclusion of these data in the Iberian secular variation curve and geomagnetic field models will help to improve the archaeomagnetic dating technique.Spanish Ministry of Economy and Competitiveness, MINECO
and the European Regional Development Fund (projects CGL2012-38481 and CGL2012-32149).
AGacknowledges partial financial support given by PAPIIT IN-105214
Mammalian Glutaminase Gls2 Gene Encodes Two Functional Alternative Transcripts by a Surrogate Promoter Usage Mechanism
Glutaminase is expressed in most mammalian tissues and cancer cells, but the regulation of its expression is poorly understood. An essential step to accomplish this goal is the characterization of its species- and cell-specific isoenzyme pattern of expression. Our aim was to identify and characterize transcript variants of the mammalian glutaminase Gls2 gene.We demonstrate for the first time simultaneous expression of two transcript variants from the Gls2 gene in human, rat and mouse. A combination of RT-PCR, primer-extension analysis, bioinformatics, real-time PCR, in vitro transcription and translation and immunoblot analysis was applied to investigate GLS2 transcripts in mammalian tissues. Short (LGA) and long (GAB) transcript forms were isolated in brain and liver tissue of human, rat and mouse. The short LGA transcript arises by a combination of two mechanisms of transcriptional modulation: alternative transcription initiation and alternative promoter. The LGA variant contains both the transcription start site (TSS) and the alternative promoter in the first intron of the Gls2 gene. The full human LGA transcript has two in-frame ATGs in the first exon, which are missing in orthologous rat and mouse transcripts. In vitro transcription and translation of human LGA yielded two polypeptides of the predicted size, but only the canonical full-length protein displayed catalytic activity. Relative abundance of GAB and LGA transcripts showed marked variations depending on species and tissues analyzed.This is the first report demonstrating expression of alternative transcripts of the mammalian Gls2 gene. Transcriptional mechanisms giving rise to GLS2 variants and isolation of novel GLS2 transcripts in human, rat and mouse are presented. Results were also confirmed at the protein level, where catalytic activity was demonstrated for the human LGA protein. Relative abundance of GAB and LGA transcripts was species- and tissue-specific providing evidence of a differential regulation of GLS2 transcripts in mammals
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