885,385 research outputs found
Na+-H+ exchange activity in brush-border membrane vesicles isolated from chick small intestine
This study was undertaken to investigate the presence of a Na+{single bond}H+ antiporter in brush-border membrane vesicles (BBMV) isolated from chick small intestine. An outwardly directed proton gradient (pH 5.5 inside, 7.5 outside) stimulated Na+ uptake into BBMV and resulted in a transient accumulation. No accumulation was observed in the absence of a proton gradient. Voltage clamping the membrane with K+ and valinomycin decreased the Na+ overshoot. Amiloride inhibited pH gradient-driven Na+ uptake in a dose-dependent manner with an IC50 of 44 μM. The relationship between pH gradient-driven Na+ uptake and external Na+ concentration followed simple, saturating Michaelis-Menten kinetics. Eadie-Hofstee analysis of the pH gradient-driven Na+ uptake indicated a single transport system with a Vmax of 33 nmol/mg protein per 15 s and a Km for Na+ of 12 mM. The initial rate of pH-driven Na+ uptake increased as the intravesicular pH decreased, with a Hill coefficient close to 1. These findings indicate that BBMV isolated from chicken small intestine posses a Na+{single bond}H+ exchanger. This exchanger does not appear to be the one involved in cell pH regulation.Dirección General de Investigaciones Científicas y Técnicas PB89-061
Building a Corpus of 2L English for Automatic Assessment: the CLEC Corpus
In this paper we describe the CLEC corpus, an ongoing project set up at the University of Cádiz with the purpose of building up a large corpus of English as a 2L classified according to CEFR proficiency levels and formed to train statistical models for automatic proficiency assessment. The goal of this corpus is twofold: on the one hand it will be used as a data resource for the development of automatic text classification systems and, on the other, it has been used as a means of teaching innovation techniques
Na+-dependent and Na+-independent betaine transport across the apical membrane of rat renal epithelium
The low renal excretion of betaine indicates that the kidney efficiently reabsorbs the betaine filtered by the glomeruli but the mechanisms involved in such a process have been scarcely investigated. We have detected concentrative and non-concentrative betaine transport activity in brush-border membrane vesicles (BBMV) from rat renal cortex and medulla. The concentrative system is the Sodium/Imino-acid Transporter 1 (SIT1) because it is Na+- and Cl--dependent, electrogenic and is inhibited by an anti-SIT1 antibody. Its apparent affinity constant for betaine, Kt, is 1.1 ± 0.5 mM and its maximal transport velocity, Vmax, 0.5 ± 0.1 nmol betaine/mg protein/s. Inhibitors of the Na+/Cl-/betaine uptake are l-proline (75%) and cold betaine, l-carnitine and choline (40-60%). Neither creatine, TEA, taurine, β-alanine, GABA nor glycine significantly inhibited Na+/Cl-/betaine uptake. The non-concentrative betaine transport system is Na+- and H+-independent, electroneutral, with a Kt for betaine of 47 ± 7 μM and a Vmax of 7.8 ± 1 pmol betaine/mg protein/s. Its transport activity is nearly abolished by betaine, followed by L-carnitine (70-80%) and proline (40-50%), but a difference from the Na+/Cl-/betaine transport is that it is inhibited by TEA (approx. 50%) and unaffected by choline. The underlying carrier functions as an antiporter linking betaine entry into the BBMV with the efflux of either l-carnitine or betaine, an exchange unaffected by the anti-SIT1 antibody. As far as we know this is the first work reporting that betaine crosses the apical membrane of rat renal epithelium by SIT1 and by a Na+- and H+-independent transport system.Ministerio de Ciencia y Tecnología BFI2003-00222Junta de Andalucía 2010/BIO-14
Employability skills developed by non-traditional students along their undergraduate program
This paper was developed in the context of the European project EMPLOY (Enhancing
the employability of non-traditional students in higher education, Erasmus Plus Program
2015-2017), a qualitative, interdisciplinary and biographical research focusing on nontraditional
university students and graduates from six European countries (Sweden,
Poland, United Kingdom, Ireland, Portugal and Spain). The project aims are, among
others: a) to understand the employability from the perspective of students and graduates;
b) to increase knowledge and understanding of the factors that promote or hinder
employability; c) to explore the impact of age, gender, social class, ethnicity and disability
in employment prospects of students; etc.
In spite of the fact that university graduates are in better conditions when accessing to the
labor market, non-traditional students might experience special difficulties related to their
specific characteristics. We lack of disaggregated information related to employment
rates for higher education graduates and there is not specific research which deepens in
the transition process of non-traditional groups. Our study is concerned with identifying
which employability skills have been developed by non-traditional students during their
stay at the University of Seville. For this purpose we consider the formal learning
associated to their syllabuses, the extracurricular training they have been involved in, as
well as the previous work experiences.
We have carried out seven biographical in-depth interviews with students of the
University of Seville (4 females, 3 males), all of them studying degrees in different areas
of knowledge: Pedagogy, Philosophy, Mechanical Engineering, Pharmacy, Biology and
Business Management. All participants were in the final year of their undergraduate
program. In addition, all of them represented different characteristics of non-traditional
students: adult and mature students (3), immigrants (2) and learners with low economic
and cultural capital (2).
As for the results and following the classification of professional competences raised by
Bunk (1994), we note that through the university syllabuses students developed the
methodological competence, that is the reaction from previous experiences and problem
solving skills. However, work experience and extracurricular activities promoted social
competence, one that enables them to collaborate with others in a communicative and
constructive way, showing interpersonal understanding. In addition, in the three training
fields, the specific skills or qualifications of the job, technical competence, were also
developed.
Finally, it can be noted that in the three areas considered in our analysis, there is a lack in
the development of the participatory competence, which refers to coordination and
organisational skills, leadership and ability to make decisions and take responsibility.Unión Europea 2014-1-UK01-KA203-00184
Wild edible plants as potential antioxidants in vegetables oils
The effect of the addition of fruits of Rosa canina and Quercus ballota and leaves of Sanguisorba minor to sunflower, seed, and olive oils on lipid oxidation during the frying process was analyzed.The three underutilised edible plants increased the oxidative stability of the sunflower oil, since the malondialdehyde (MDA) content was significantly decreased with respect to values of the control sunflower oil after the heating process. However, in olive oil, the effect of these edible plants on decreasing the lipid peroxidation was only evident for the highest concentration, while in seed oil the addition of the edible plant showed a prooxidant effect.Thus, these wild edible plants could be used to enrich vegetable oils with low content of natural antioxidant, such as sunflower oil, and avoid or decrease the use of synthetic antioxidant
Homicide Profiles Based on Crime Scene and Victim Characteristics
One of the current trends in homicide research includes developing works based on scientific study and empirical evidence, which offer conclusions that can be used in an operational manner during police investigations. The objective of this study was to identify homicide characteristics from behaviors carried out on the crime scene and victim characteristics associated with those of the perpetrators of these crimes in Spain. The sample consisted of 448 homicide cases from the database of the Homicide Revision Project led by the Office of Coordination and Studies of the Secretary of State and Security. After creating six classification tree models, it was found that the modus operandi of the aggressor and the victim characteristics may permit hypothesizing about the demographic characteristics of the perpetrator (gender, age, and country of origin), his/her criminal record, and the type of relationship with the victim. Furthermore, the importance of the study of victimology during a criminal investigation is highlighted, as it may indirectly offer information about the potential perpetrator. The findings of this study suggest that criminal profiling contributes notably to the decision-making process to establish more rigorous suspect prioritization, improve the management of human resources and materials, and increase the efficiency of criminal investigations
Optimizing a Simple Natural Dye Production Method for Dye-Sensitized Solar Cells: Examples for Betalain (Bougainvillea and Beetroot Extracts) and Anthocyanin Dyes
We present a study about the sensitizers extracted from natural resources. This paper focuses on how to select, extract and characterize natural dyes, giving some guides to establish a protocol for the whole process of fabricating and using these dyes. The influence of the extraction solvent and method, and of parameters such as pH are analyzed. Also, dye precursor and dye extract stability have been studied, as well as how the dye adsorbs onto substrates and the effect of mixing or concentrating the extracts. Results concerning betalain pigments present in bougainvillea and beetroot extracts, and anthocyanins in eggplant extracts, analyzed by using UV-Vis spectrometry, are included. As an example of application, we report procedures intended to test and enhance the dye potential as a main component of dye-sensitized solar cells (DSSCs). DSSCs mimic nature’s photosynthesis and have some advantages like an easy and low-cost fabrication procedure. Their efficiency depends on its design and fabrication process and also on the different components involved. Hence, optimizing each component is essential to achieve the best performance, and thus the dye used as a sensitizer is crucial. We fabricate cells by using a simple procedure: As the interest is focused on the sensitizer, the same consecutive steps are followed, varying only the dye extract. Among all the natural-dyes tested, beetroot extract reaches up to 0.47% cell efficiency, which is near the highest values found in literature for this pigment
Reflexiones sobre las características mecánicas de los bailarines de pantomima
El presente artículo tiene como objetivo investigar la experiencia cinestésica
de la danza, y especialmente de la danza de la pantomima, en De Saltatione de
Luciano y en la oración 64 de Libanio, Una respuesta a Aristides en nombre de
los bailarines, desde la perspectiva de la mecánica. En concreto, la pantomima
se discutirá en yuxtaposición con el concepto de automatización mecánica, un
aspecto hasta aquí inexplorado, pese a su gran importancia, especialmente si
se tiene en cuenta que a partir del período helenístico autómatas y procesiones
teatrales con artefactos de ingeniería se consideraron un mecanismo de
entretenimiento popular y, como tales, ejercieron gran influencia en la estética
del público. En este sentido, primero tengo la intención de examinar el concepto
de mímesis pantomímica como una reproducción mecánica del movimiento,
es decir, gestos y posturas. A continuación, detectaré el vocabulario de la
función de mecanismos / función de los mecanismos que generalmente se halla
incrustado en la retórica de la danza al examinar el movimiento forzado tanto
en la pantomima como en la mecánica antigua.This paper aims to investigate the kinaesthetic experience of dance, and
especially of pantomime dance in Lucian’s De Saltatione and in Libanius’ oration
64, A Reply To Aristides On Behalf Of The Dancers, from the perspective of the
mechanical. Specifically, pantomime will be discussed in juxtaposition with the
concept of mechanical automation. Until now, this aspect remains unexplored;
however, this is of great importance, particularly if we take into consideration
that from the Hellenistic period onwards theatrical automata and processions
with engineered artefacts were considered to be a popular entertainmentmechanism and, as such, they exerted great influence on the public’s aesthetic.
In this respect, I intend first to survey the concept of pantomimic mimesis as a
mechanical reproduction of motion, i.e. gestures and postures. Next, I shall detect
the vocabulary of mechanisms/mechanisms’ function that is generally embedded
in dance rhetoric by examining forced motion both in pantomime and ancient
mechanics
Characterising epithelial tissues using persistent entropy
In this paper, we apply persistent entropy, a novel topological statis-
tic, for characterization of images of epithelial tissues. We have found
out that persistent entropy is able to summarize topological and geomet-
ric information encoded by -complexes and persistent homology. After
using some statistical tests, we can guarantee the existence of signi cant
di erences in the studied tissues.Ministerio de Economía y Competitividad MTM2015-67072-
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