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714 results on '"Crespo, D."'

201. The supraoptic nucleus: a morphological and quantitative study in control and hypophysectomised rats

Author

Crespo, D, Ramos, J, Gonzalez, C, and Fernandez-Viadero, C

Subjects
Male, Neurons, Age Factors, Animals, Cell Count, Rats, Inbred Strains, Supraoptic Nucleus, Research Article, Hypophysectomy, Rats
Abstract

Several quantitative and morphometric parameters were analysed in the pars principalis of the supraoptic nucleus (SON) of the hypothalamus in control and hypophysectomised rats at several postnatal ages. The cell number in the control group remained approximately constant from Day 1, when it was 5034 +/- 348 (mean +/- S.D.M.), until Day 90 when the number of cells was 5234 +/- 110. In the group that was hypophysectomised on Day 60, the number of neurons on Day 90 was 1366 +/- 131, which represents a loss of 74% of the neurons. Morphometric parameters on Day 90 indicated a significant difference in nuclear size, 52.1 +/- 6.7 microns 2 in controls and 57.3 +/- 6.8 microns 2 in the hypophysectomised group. Based on these results, it is concluded that there is no postnatal loss of neurons in the pars principalis of the SON in normal rats. As a consequence of the stress induced by hypophysectomy, the remaining cell population undergoes adaptive changes in the nuclear RNA synthesis machinery of neurohypophyseal hormone precursors in order to compensate for the reduction in the number of neurosecretory neurons.

Published
1990

206. Prospective evaluation of peginterferon alfa-2a (40KD)/ribavirin in CHC, IFN/Ribavirin nonresponders/relapsers

Author

Parise, E., primary, Meirelles, A., additional, Martinelli, A., additional, Lacet, C., additional, Correa, E., additional, Cotrim, H., additional, Sette, H., additional, Cheinquer, H., additional, Gallizi, J., additional, Fonseca, J., additional, Parana, R., additional, da Silva, R., additional, Spinelli, V., additional, Gomes, A., additional, Crespo, D., additional, Lima, L., additional, Pereira, L., additional, Tiexeira, R., additional, Amorim, W., additional, and Tatsch, F., additional

Published
2003
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209. Mössbauer Analysis of Low-Temperature Bainite.

Author

Bruna, P., Pradell, T., Crespo, D., García-Mateo, C., and Bhadeshia, H. K. D. H.

Subjects
BAINITE, AUSTENITE, SPECTRUM analysis, CARBON, MICROSTRUCTURE, CEMENTITE
Abstract

Low-temperature bainite, obtained by the transformation of austenite at temperatures as low as 200°C for times as large as several days, has been reported to have extraordinary mechanical properties including the highest reported hardness of any bainitic steel. The unusual properties are a consequence of the fine scale of the microstructure, which contains bainite plates with thickness in the range 20–40 nm. The microstructure also contains carbon-enriched retained austenite which contributes to the properties via a number of mechanisms. In this work, the microstructure of a high carbon bainitic steel with Si to avoid cementite precipitation and Co to accelerate the transformation has been studied using Mössbauer spectroscopy for a series of samples transformed isothermally at 200°C for time periods of 26, 34 and 96 hours. The total austenite content is almost identical (∼13 wt%) for these samples although the carbon concentrations of the phases differ as a function of transformation time. The austenite increases its carbon content from 5.4 atomic % after 26 h transformation to 6.3 at.% after 96 h, while the final bainitic phase retains about 2.2 at.% of C. These results are consistent with data obtained using atom probe tomography for samples transformed isothermally for 12 days. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2005
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233. Implications of nutrient decline in the seagrass ecosystem success.

Author

Cardoso, P.G., Leston, S., Grilo, T.F., Bordalo, M.D., Crespo, D., Raffaelli, D., and Pardal, M.A.

Subjects
SEAGRASSES, ZOSTERA noltii, ESTUARINE restoration, HYSTERESIS, EUTROPHICATION, BIOMASS
Abstract

Abstract: The Mondego estuary (Portugal) suffered major changes in environmental quality due to eutrophication, however, in the late 1990s a restoration project was implemented in order to return the system to its original condition. The main goal of this paper is to evaluate the ecosystem response to the restoration measures applied at three different levels: water quality, primary producers and primary consumers. In post-restoration period a clear decline was observed in dissolved inorganic nitrogen which was reflected in the gradual recovery of Zostera noltii and a concomitant decline in green macroalgae. Macrobenthic assemblages responded variably to the recovery process. In the seagrass bed and intermediate area, there was a large increase in total biomass, but in the eutrophic area species diversity increased. Despite improvement in the ecological status of the system, full recovery has not been achieved yet, possible due to hysteresis in the dynamics of this system. [Copyright &y& Elsevier]

Published
2010
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243. Spiral vortices between concentric cylinders

Author

Sánchez, J., Crespo, D., and Marquès, F.

Abstract

Spiral vortices appearing in Couette-Taylor flows are studied by means of numerical simulation. Transition curves from Couette to spiral vortices for different radius ratios and wavenumbers have been calculated in order to test our technique. Critical Reynolds numbers, angular velocities and slopes of the spirals at the onset of the instability agree with previous results [1]. Non-linear solutions obtained by a pseudospectral collocation method are studied, and they show a weak net axial flow. In order to counteract this effect, which is absent in the usual experimental set-up, an axial pressure gradient has been included. This procedure has proved to be sufficient to make the axial flow negligible. The onset of a quasiperiodic flow for larger Reynolds numbers, corresponding to a secondary bifurcation is also presented.

Published
1993
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245. The role of dopamine receptors in lymphocytes and their changes in schizophrenia

Author

Penedo, M.A., Rivera-Baltanás, T., Pérez-Rodríguez, D., Allen, J., Borrajo, A., Alonso-Crespo, D., Fernández-Pereira, C., Nieto-Araujo, M., Ramos-García, S., Barreiro-Villar, C., Caruncho, H.J., Olivares, J.M., and Agís-Balboa, R.C.

Abstract

Dopamine and its 5 receptors, which are grouped into two families (D1-like and D2-like), modulate functions at a systemic level in both the central nervous system and periphery. The central nervous system and the immune system are the main adaptive systems, which participate in a continuous and functional crosstalk to guarantee homeostasis. On binding to its 5 dopamine receptors, dopamine acts as a co-regulator of the immune system, contributing to the interaction of the central nervous system and inflammatory events and as a source of communication between the different immune cells. Dopaminergic perturbations in the central nervous system are observed in several neurological and psychiatric disorders. Schizophrenia is one of the most common mental disorders with a poorly understood pathoaetiology that includes genetic and environmental components that promote alterations in the dopaminergic system. Interestingly, abnormalities in dopamine receptors expression in lymphocytes of schizophrenia patients have been reported, often significantly correlating with the severity of the psychotic illness. Here, we review the current literature regarding the dopaminergic system in human lymphocytes and its alterations in schizophrenia.

Published
2021
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246. Realistic scenarios of environmental disturbance lead to functionally important changes in benthic species-environment interactions.

Author

Dolbeth, M., Crespo, D., Leston, S., and Solan, M.

Subjects
*ECOLOGICAL disturbances, *INVERTEBRATE communities, *BIOTURBATION, *SPECIES diversity, *BENTHIC ecology, *COMMUNITY organization, *MEDIATION
Abstract

Changes in community structure concurrent with environmental forcing often form a precursor to changes in species diversity, and can have substantive consequences for ecosystem functioning. Here, we assess the effects of altered levels of evenness that are representative of different levels of eutrophication and changes in salinity associated with altered precipitation patterns, on the mediation of nutrient release by sediment-dwelling invertebrate communities. We find that an adjustment towards a more even distribution of species corresponds with an increase in sediment particle reworking that, in general, translates to increased levels of nutrient release. This response, however, is dependent on the functional role of each species in the community and is influenced by concomitant changes in salinity, especially when salinity extends beyond the range typically experienced by the community. Overall, our findings highlight the dynamic nature of species contributions to functioning and reinforce the importance of understanding when, and how, the mechanistic basis of species-environment interactions are modified as the influence of abiotic and biotic factors flex under periods of directional forcing. • The effect of benthic communities' altered evenness and salinity change was evaluated. • Higher evenness generally led to an increase in bioturbation and nutrient release. • Results were highly dependent on each species functional role in the community. • Salinity levels beyond those typical encountered alter evenness-function relations. • The magnitude and direction of changes in functioning is context dependent. [ABSTRACT FROM AUTHOR]

Published
2019
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249. The AMS-RICH velocity and charge reconstruction

Author

Aguilar-Benitez, M., Arruda, L., Barao, F., Baret, B., Barrau, A., Barreira, G., Belmont, E., Berdugo, J., Borges, J., Buenerd, M., Casadei, D., Casaus, J., Cortina, E., Costado, M., Crespo, D., Delgado, C., Diaz, C., Derome, L., Goncalves, P., Garcialopez, R., La Guia, C., Herrero, A., Lanciotti, E., Laurenti, G., Malinin, A., Mana, C., Jesus Marin, Mangin-Brinet, M., Martinez, G., Menchaca-Rocha, A., Palomares, C., Pereira, R., Pimenta, M., Putze, A., Sallaz-Damaz, Y., Se, Es, Sevilla, I., Torrento, A., Vargas-Trevino, M., Veziant, O., Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia, AMS, bibliotheque, LPSC, and Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia

Subjects
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Physics::Instrumentation and Detectors, Astrophysics (astro-ph), FOS: Physical sciences, High Energy Physics::Experiment, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics
Abstract

The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed., Contribution to the ICRC07, Merida, Mexico (2007); Presenter: F. Barao

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