933 research outputs found
Crecimiento gonadal y reproducción del erizo de mar Sphaerechinus granularis (Lamarck, 1816) (Echinodermata, Echinoidea) en el sureste de España
The gonadal index and reproductive state of the sea urchin Sphaerechinus granularis were studied for a year in three populations from southeast Spain. The development of the gonad during the period of study was assessed using histological methods and four maturity stages were considered for female specimens and two for male specimens. The study of gonad development showed a clearly defined annual cycle of gametogenesis with a single spawning period in summer-autumn. It begins in June at Torremuelle and Palmeral and a month later at La Herradura. The three populations exhibited similar reproductive patterns, having mature gonads in almost all the months. Though the environmental conditions were similar, the population from La Herradura had the highest Gonadosomatic Index value (GSI) and that from Torremuelle the lowest one.Se ha estudiado el índice gonadosomático y los estados reproductivos del erizo de mar Sphaerechinus granularis durante un año en tres poblaciones del sureste de España. El desarrollo de la gónada se estudió usando métodos histológicos; además, el estado de los individuos se determinó utilizando cuatro categorías de desarrollo gonadal para las hembras y dos para los machos. Existe un único periodo de puesta a lo largo del año, entre verano y otoño. En las estaciones de Torremuelle y Palmeral la puesta comienza en junio mientras que en La Herradura tiene un retraso de un mes. Las tres poblaciones muestran patrones reproductivos semejantes y se caracterizan por tener gónadas maduras casi todos los meses, aunque en proporciones distintas. Los valores del índice gonadosomático son mayores en La Herradura y menores en Torremuelle a pesar de que las condiciones ambientales son similares
Cambios ontogenéticos e intraespecíficos observados en la rádula de Polycera aurantiomarginata García and Bobo, 1984 (Gastropoda Opisthobranchia)
Polycera aurantiomarginata García and Bobo 1984 has a stable population in the intertidal area of El Portil beach (Huelva, SW Spain). This fact allowed specimens of different sizes to be collected from March 2001 to December 2003. In this paper, the ontogenetic variations of the radula of P. aurantiomarginata are studied. The radulae of 141 specimens were examined, 138 from El Portil and 3 from La Herradura (Granada, SE Spain). Specimens of 1.5-2 mm in length lack the typical radula described for P. aurantiomarginata. They have the so called pre-radula whose teeth are different in size and shape from the typical radula of the adults. In the specimens of 3 and 4 mm the pre-radula coexists with the characteristic radula, which is the single structure present in the specimens larger than 4 mm. The following features of the radula are included in this study: radular length, number of teeth rows and length of the outer lateral teeth. According to the three measured variables, the affinities among specimens without a pre-radula were established through cluster analysis, which defined three different groups (4-10 mm, 11-22 mm and 23-48 mm). Correlations between specimen length and radula length, number of rows and mean length of outer lateral teeth were significant. Feeding strategies could be related to the different morphology of the radula established by the Cluster analysis.Polycera aurantiomarginata García y Bobo, 1984 muestra una población estable y en la localidad de El Portil (Huelva, SW de España), lo que ha permitido la recolección, desde marzo de 2001 hasta diciembre de 2003, de un alto número de ejemplares de todos los tamaños. En el presente estudio se ha extraído la rádula de 141 animales, 138 recogidos en la zona intermareal de El Portil y 3 en La Herradura (Granada). Los tamaños de los animales han oscilado entre 1.5 mm y 48 mm. Se ha podido observar en los individuos de entre 1.5 y 2 mm la existencia de una pre-rádula cuyos dientes son morfológicamente diferentes a los de la rádula de los individuos mayores; sin embargo, en los ejemplares de 3 y 4 mm esta pre-rádula coexiste con la rádula típica, siendo esta estructura la única presente en individuos de longitud igual o mayor a 4 mm. A cada una de las rádulas extraídas, tanto con pre-rádula o sin ella, se le ha medido la longitud total de la cinta, la longitud del diente lateral externo y el número de filas de dientes. Considerando los tres parámetros medidos, las afinidades entre los ejemplares sin pre-rádula se establecieron a partir de análisis de Cluster, que definieron tres grupos distintos (4-10 mm, 11-22 mm y 23-48 mm). Las correlaciones existentes entre la longitud de los individuos y la longitud de la rádula, el número de filas y la longitud media de los dientes fueron significativas. Las diferencias morfológicas reconocidas en los grupos considerados podrían estar relacionadas con distintas estrategias alimentarias.
Novel two-component systems implied in antibiotic production in Streptomyces coelicolor
[EN] The abundance of two-component systems (TCSs) in Streptomyces coelicolor A3(2) genome indicates their importance in the physiology of this soil bacteria. Currently, several TCSs have been related to antibiotic regulation, and the purpose in this study was the characterization of five TCSs, selected by sequence homology with the well-known absA1A2 system, that could also be associated with this important process. Null mutants of the five TCSs were obtained and two mutants (ΔSCO1744/1745 and ΔSCO4596/4597/4598) showed significant differences in both antibiotic production and morphological differentiation, and have been renamed as abr (antibiotic regulator). No detectable changes in antibiotic production were found in the mutants in the systems that include the ORFs SCO3638/3639, SCO3640/3641 and SCO2165/2166 in any of the culture conditions assayed. The system SCO1744/1745 (AbrA1/A2) was involved in negative regulation of antibiotic production, and acted also as a negative regulator of the morphological differentiation. By contrast, the system SCO4596/4597/4598 (AbrC1/C2/C3), composed of two histidine kinases and one response regulator, had positive effects on both morphological development and antibiotic production. Microarray analyses of the ΔabrC1/C2/C3 and wild-type transcriptomes revealed downregulation of actII-ORF4 and cdaR genes, the actinorhodin and calcium-dependent antibiotic pathway-specific regulators respectively. These results demonstrated the involvement of these new two-component systems in antibiotic production and morphological differentiation by different approaches. One is a pleiotropic negative regulator: abrA1/A2. The other one is a positive regulator composed of three elements, two histidine kinases and one response regulator: abrC1/C2/C3SIThis work has been supported by grants GEN2003-20245-C09-02 from the Comisión Interministerial de Ciencia y Tecnología (CICYT) to R. Santamaría, SA072A07 from the Junta de Castilla y León to M. Díaz and BFU2010-17551 from Ministerio de Ciencia e Innovación (MICINN) to M. Díaz. A. Y. was a holder of a predoctoral grant from the Junta de Castilla y León, S.R. has a predoctoral grant from the Consejo Superior de Investigaciones Científicas (CSIC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Influencia de la formación previa en el proceso de integración en la universidad
En este trabajo se analizan las características del proceso de integración en la universidad de los estudiantes de Ingeniería del Software e Ingeniería de Computadores de la Universidad Politécnica de Madrid, en relación con los estudios previamente cursados (estudios superiores de Formación Profesional o Bachillerato), con el fin de proponer acciones específicas. En el estudio realizado, la unidad de análisis es la experiencia estudiantil durante el primer año y se han combinado herramientas cuantitativas y cualitativas para la recogida de información. Se ha comprobado que las dificultades en el proceso de integración en la universidad tienen relación con la modalidad de acceso. Los estudiantes procedentes de Formación Profesional tienen que hacer un esfuerzo importante para superar sus deficiencias de formación previa en materias básicas como Matemáticas y Física, mientras que los problemas que encuentran los estudiantes procedentes de Bachillerato tienen que ver con el desconocimiento previo de la titulación y las dificultades de planificación y organización.In this paper we analyze the integration process into college studies of first year Software Engineering and Computer Engineering students at the Polytechnic University of Madrid. We do this in connection with their previously completed studies (higher education vocational training or high school), with the aim of proposing specific actions. To study the process of integration into university, the unit of analysis is the student’s experience during the first year. Both quantitative and qualitative information gathering tools have been used, and it has been found that difficulties in the integration process depend heavily on the student’s access mode. Students coming from vocational training have to make a major effort to overcome deficiencies of prior training in basic subjects, such as mathematics or physics, while the problems encountered by students coming from high school have to do with their lack of knowledge of the nature of the degree they intend to study, as well as planning and organizational difficulties.Facultad de Informátic
Economic costs of outbreaks of acute viral gastroenteritis due to norovirus in Catalonia (Spain), 2010-2011
Background To determine the direct and indirect costs of outbreaks of acute viral gastroenteritis (AVG) due to norovirus in closed institutions (hospitals, social health centers or nursing homes) and the community in Catalonia in 2010-11. Methods Information on outbreaks were gathered from the reports made by epidemiological surveillance units. Direct costs (medical visits, hospital stays, drug treatment, sample processing, transport, diagnostic tests, monitoring and control of the outbreaks investigated) and indirect costs (lost productivity due to work absenteeism, caregivers time and working hours lost due to medical visits) were calculated. Results Twenty-seven outbreaks affecting 816 people in closed institutions and 74 outbreaks affecting 1,940 people in the community were detected. The direct and indirect costs of outbreaks were ¿ 131,997.36 (¿ 4,888.79 per outbreak) in closed institutions and ¿ 260,557.16 (¿ 3,521.04 per outbreak) in community outbreaks. The cost per case was ¿ 161.76 in outbreaks in closed institutions and ¿ 134.31 in community outbreaks. The main costs were surveillance unit monitoring (¿ 116,652.93), laboratory diagnoses (¿ 119,950.95), transport of samples (¿ 69,970.90), medical visits (¿ 25,250.50) and hospitalization (¿ 13,400.00). Conclusions The cost of outbreaks of acute viral gastroenteritis due to norovirus obtained in this study was influenced by the number of people affected and the severity of the outbreak, which determined hospitalizations and work absenteeism. Urgent reporting of outbreaks would allow the implementation of control measures that could reduce the numbers affected and the duration of the illness and thus the costs derived from them
Hospital-acquired influenza infections detected by a surveillance system over six seasons, from 2010/2011 to 2015/2016
Background: In addition to outbreaks of nosocomial influenza, sporadic nosocomial influenza infections also occur but are generally not reported in the literature. This study aimed to determine the epidemiologic characteristics of cases of nosocomial influenza compared with the remaining severe cases of severe influenza in acute hospitals in Catalonia (Spain) which were identified by surveillance. Methods: An observational case-case epidemiological study was carried out in patients aged ≥18 years from Catalan 12 hospitals between 2010 and 2016. For each laboratory-confirmed influenza case (nosocomial or not) we collected demographic, virological and clinical characteristics. We defined patients with nosocomial influenza as those admitted to a hospital for a reason other than acute respiratory infection in whom ILI symptoms developed ≥48 h after admission and influenza virus infection was confirmed using RT-PCR. Mixed-effects regression was used to estimate the crude and adjusted OR. Results: One thousand seven hundred twenty-two hospitalized patients with severe laboratory-confirmed influenza virus infection were included: 96 (5.6%) were classified as nosocomial influenza and more frequently had > 14 days of hospital stay (42.7% vs. 27.7%, P < .001) and higher mortality (18.8% vs. 12.6%, P < .02). The variables associated with nosocomial influenza cases in acute-care hospital settings were chronic renal disease (aOR 2.44 95% CI 1.44-4.15) and immunodeficiency (aOR 1.79 95% CI 1.04-3.06). Conclusions: Nosocomial infections are a recurring problem associated with high rates of chronic diseases and death. These findings underline the need for adherence to infection control guidelines
Differential expression and localization of transient receptor potential vanilloid 1 in rabbit and human eyes
Producción CientíficaSummary. Introduction: The superfamily of transient
receptor potential (TRP) cation channels is involved in
nociception. Members of this family, such as the
vanilloid receptor type 1 (TRPV1) channel, are activated
by a wide range of stimuli including heat (>43°C), low
pH (<6.5), hypoxia, and hypertonicity. Here we report
TRPV1 expression in rabbit and human eyes.
Material and methods: We analyzed the expression
of TRPV1 mRNA by quantitative reverse transcription
polymerase chain reaction (qRT-PCR) and protein by
immunohistochemistry in eyes of New Zealand White
rabbits and humans.
Results: In rabbit and human eyes, TRPV1 protein
was present in all layers of the corneal epithelium, but
only in the basal layer of the conjunctiva. It was also in
the ciliary and lens epithelia of both species as well as in
the secretory cells of the rabbit lacrimal gland. The
retinal pigment epithelium was positive for this protein
in both species. TRPV1 was also present in rabbit Müller
cells, where it had a similar pattern of expression to
vimentin intermediate filaments. Analysis by qRT-PCR
showed that TRPV1 mRNA was found in all of the
structures where the protein was present. The highest
level was in the lens and the lowest in the retina.
Conclusion: TRPV1 is expressed in cells that are
particularly active in Ca2+ exchange as well as in cells
with significant water transport activity. Because TRPV1
is a Ca2+ channel, it probably functions in the regulation
of both water and Ca2+ movements in ocular tissues
Real-time robust automatic speech recognition using compact support vector machines
In the last years, support vector machines (SVMs) have shown excellent performance in many applications, especially in the presence of noise. In particular, SVMs offer several advantages over artificial neural networks (ANNs) that have attracted the attention of the speech processing community. Nevertheless, their high computational requirements prevent them from being used in practice in automatic speech recognition (ASR), where ANNs have proven to be successful. The high complexity of SVMs in this context arises from the use of huge speech training databases with millions of samples and highly overlapped classes. This paper suggests the use of a weighted least squares (WLS) training procedure that facilitates the possibility of imposing a compact semiparametric model on the SVM, which results in a dramatic complexity reduction. Such a complexity reduction with respect to conventional SVMs, which is between two and three orders of magnitude, allows the proposed hybrid WLS-SVC/HMM system to perform real-time speech decoding on a connected-digit recognition task (SpeechDat Spanish database). The experimental evaluation of the proposed system shows encouraging performance levels in clean and noisy conditions, although further improvements are required to reach the maturity level of current context-dependent HMM based recognizers.Spanish Ministry of Science and Innovation TEC 2008-06382 and TEC 2008-02473 and Comunidad Autónoma de Madrid-UC3M CCG10-UC3M/TIC-5304.Publicad
La Enseñanza de las Matemáticas en la E.U. de Informática
El Departamento de Matemática Aplicada (E. U. Informática) de la Universidad Politécnica de Madrid tiene a su cargo la docencia de todas las asignaturas de matemáticas de las titulaciones de I.T.I. de Sistemas y de I.T.I. de gestión, implantadas en el curso 1992-93. Asignaturas troncales: Álgebra, Análisis matemático y métodos numéricos, Matemática discreta y estadística. Asignaturas optativas o de libre elección: Laboratorio de matemáticas, Lógica, Métodos de cálculo científico, Geometría computacional, Investigación operativa (Sistemas), investigación operativa (gestión), geometría computacional avanzada y Tratamiento estadístico de datos con ordenador. Un denominador común en todas las asignaturas es la realización de prácticas con ordenador. En las clases prácticas el papel de los estudiantes es más activo y pensamos que Éste es un factor positivo para el aprendizaje. Otro aspecto contemplado en todas las asignaturas es el de facilitar al alumno un material de trabajo adecuado, con la posibilidad de contar desde el principio de curso con información suficiente sobre los contenidos, bibliografía, metodología y normas de evaluación, así como con los enunciados de problemas y prácticas que se irán abordando a lo largo del curso. También se les facilita información sobre exámenes de cursos anteriores. En la ponencia se comentan algunos detalles sobre la planificación de las asignaturas troncales
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