252 research outputs found

    ACTIVIDAD RESPIRATORIA EN EL HORIZONTE ORGANICO DE SUELOS DE ECOSISTEMAS FORESTALES DEL CENTRO Y SUR DE CHILE

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    The soil litter layer (Oi and Oe horizons) of forest ecosystems is used as both habitat and nutrient and energy sourcefor a great diversity of soil organisms. As a consequence, carbon (C) flows from plant detritus as CO2by respiration of litter biota. Here we measured and compared the respiratory activity under laboratory conditions of litter samples collected from three forest types of Central and Southern Chile: Nordpatagonian forest (Nothofagus), EvergreenConiferous forest (Fitzroya) and Schlerophyllous forest (Cryptocarya). Samples of the later forest were separated inthree particle size fractions (>2.4; 2.4-1.2 and < 1.2 mm) in order to tests the hypothesis of constancy of respirationrate per dry mass unit during decomposition of homogeneous substrates, derived from theoretical model of Ågren &Bosatta, accounting for the effect of water content of samples. Incubations were done at 20 ºC, during up to 22 days and the CO2 produced was collected in alkaline solution and measured by titration. Curves of cumulative C-CO2production were built, estimating respiration rates per dry mass unit as the slope of linear portion of curves. Unbiasedestimates of rates were obtained by means of resampling without replacement (bootstrap). Respiration rates per drymass varied between 2.8 and 57.7 mg C-CO2 100 g-1 day-1, being higher in the litter samples of Nordpatagonian forest.In Schlerophyllous forest litter, we did not find significant differences among particle size fractions. However, thehigher respiration rate observed in the fine fraction (11.8 mg C-CO2 100 g-1 d-1) was associated to its higher watercontent. We did not find significant differences between respiration activity of litter of Coniferous and Nordpatagonianrain forests, despite the huge difference of its C/N ratio. The results are discussed within the theoretical framework ofdecomposition of organic matter and the carbon dynamics within soils of forest ecosystems.El mantillo del suelo (horizontes Oi y Oe) de ecosistemas boscosos es utilizado como hábitat, fuente de nutrientes yenergía para una gran diversidad de organismos. Ocurre, en consecuencia, un flujo de carbono (C) desde el detritusdebido a la producción de CO2 por respiración de la biota. En este trabajo se midió y comparó la actividad respiratoriaen condiciones de laboratorio de muestras de mantillo, colectadas en tres tipos de bosques del centro y sur de Chile:bosque Nordpatagónico (Nothofagus), bosque Siempreverde de Coníferas (Fitzroya) y bosque Esclerófilo (Cryptocarya).Las muestras de este último se separaron en tres fracciones de tamaño de partículas (>2,4; 2,4-1,2 y < 1,2 mm), con elfin de poner a prueba la hipótesis de la constancia de la tasa de respiración por unidad de masa seca durante ladescomposición de sustratos homogéneos, derivada del modelo teórico de Ågren & Bosatta, tomando en cuenta elcontenido hídrico de las muestras. Las incubaciones se realizaron a 20 ºC, durante un máximo de 22 días, y el CO2producido fue colectado en solución alcalina y determinado por titulación. Se construyeron curvas de producciónacumulada de C-CO2 , estimando la tasa de respiración por unidad de masa seca por la pendiente de la porción lineal dedichas curvas. Se obtuvieron estimaciones insesgadas de las tasas mediante remuestreo sin reposición. Las tasas derespiración por unidad de masa seca fluctuaron entre 2,8 y 57,7 mg C-CO2 100 g-1 día-1, siendo mayores en las muestrasdel bosque Nordpatagónico. En la hojarasca del bosque Esclerófilo no se observaron diferencias significativas entre lasfracciones de tamaño de partículas. Sin embargo, la mayor tasa respiratoria observada en la fracción fina (11,8 mg CCO2100 g-1 d-1) estuvo asociada a un mayor contenido hídrico de la misma. No se encontraron diferencias significativasentre la actividad respiratoria de la hojarasca de los bosques de Coníferas y Nordpatagónico, a pesar de las diferenciasen su relación C/N. Se discuten los resultados en el contexto teórico del proceso de descomposición de la materiaorgánica y la dinámica del carbono en suelos de ecosistemas forestales

    Switching from natalizumab to fingolimod: an observational study

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    Background – Multiple sclerosis patients who discontinue using natalizumab are at risk of a rebound in disease activity. However, the optimal alternative therapy is not currently known. Aims of the study – We report on clinical and MRI data and patient safety in a group of relapsing–remitting multiple sclerosis patients who tested seropositive for the JC virus and who have switched from natalizumab to fingolimod because of concerns regarding PML risks. Methods – The test for JC virus antibodies was performed in 18 relapsing–remitting multiple sclerosis patients who were being treated with natalizumab for more than 1 year. Eight seropositive patients switched to fingolimod while the seronegative patients continued with natalizumab. Results – After switching to fingolimod, five of eight patients (63%) experienced clinical relapses, and MRI activity was detected in six of eight patients (75%). Neither clinical relapses nor MRI activity was observed in the patients who continued with natalizumab. No serious adverse effects were detected. Conclusions – Natalizumab is an effective treatment for relapsing–remitting multiple sclerosis, but its discontinuation continues to be a complex problem. All of the therapies tried thus far, including fingolimod, have been unable to control the reactivation of the disease. Further studies addressing alternative therapies after natalizumab discontinuation are necessary

    A global phylogeny of Elysia Risso, 1818 (Gastropoda: Heterobranchia): molecular systematic insights focusing on European taxa and description of a new species

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    The genus Elysia comprises about one-third of the species richness in Sacoglossa. However, the species diversity in the genus remains poorly characterized in some areas like the north-eastern Atlantic and Mediterranean waters. To clarify the systematics of this genus and to characterize the species diversity in undersampled regions, we performed an integrative study based on a thorough literature review, molecular and morphological analyses, and species delimitation approaches. We conducted phylogenetic analyses of partial sequences of two mitochondrial genes (COI and 16S) and two nuclear genes (H3, 28S) using Bayesian inference and maximum likelihood methods, which confirmed the presence of five of the recognized European Elysia species: Elysia viridis, E. timida, E. flava, E. margaritae, and E. rubeni. Moreover, a new species (Elysia azorica sp. nov.) was identified in the Azores, and E. gordanae, currently considered a junior synonym of E. margaritae, was recovered as a distinct species. In addition, we consider E. hetta as a junior synonym of E. gordanae, and E. translucens as a taxon inquirendum. Finally, the tropical E. evelinae is recorded along European coasts for the first time. Our results demonstrate the value of integrative approaches in resolving taxonomic uncertainty surrounding polymorphism and unravelling potential cases of cryptic or pseudocryptic species complexes

    SMOS soil moisture product validation in croplands

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    A validation campaign has been carried out to evaluate the Level 2 Soil Moisture (SM) product (version 5.51) given by the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite in the Pampean Region of Argentina. The study region was selected because it is a plain, avoiding topography problems, with an SMOS nominal land use class (low vegetation crops, 1-2m height). Transects of ground SM measurements were collected at 5-cm and 6-cm depth using Delta-T ThetaProbe ML2x and Stevens Hydra Probe II SM sensors, respectively. The volumetric measurements were calibrated using gravimetric and bulk density data collected at the same time as the SM sensor measurements. The SM transects covered ISEA-grid SMOS nodes over four extensive agricultural areas with prevalence of soy crops (site 1: -32.982N, -62.505E; site 2: -32.510N, -62.788E; site 3: -32.024N, -63.692E; and site 4: -37.315N, -58.868E, WGS84). The validation sites were selected taking as reference the locations of permanent SM stations property of the Argentinean Comisión Nacional de Actividades Espaciales (CONAE, National Commission of Space Activities), Instituto Nacional de Tecnología Agropecuaria (INTA, National Institute of Farming Technology) and Instituto de Hidrología de Llanuras (IHLLA, Plain Hydrology Institute). Therefore, additionally to validate the SMOS SM product with the ground data collected during the experimental campaign, the measurements are useful to evaluate the station SM data reliability at the SMOS spatial resolution with the aim of using station data series as reference to test different versions of the SMOS SM product. Previously to the campaign, SMOS SM data variability, ESA Globcover land use classification, soil edaphic properties, water bodies and topography were analyzed around the station locations to select the best sites and the experimental methodology. Temperature vegetation dryness index (TVDI) temporal and spatial variability was also studied at the sites. Additionally, transects of land surface temperature were carried out with Cimel Electronique CE312 6-band radiometers concurrently with thermal-infrared (TIR) satellite overpasses. In previous works, we studied the dependence of land surface emissivities on SM. The analysis of concurrent TIR and SM data make possible to evaluate the utility of the SMOS SM product to improve land surface emissivities and temperature determinations from satellite, giving an added value to the research

    Health-related quality of life in well-differentiated metastatic gastroenteropancreatic neuroendocrine tumors

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    Spanish Neuroendocrine Tumor Group (GETNE)© 2015, Springer Science+Business Media New York. Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare neoplasms capable of producing hormones. The development of new treatments has improved progression-free survival, albeit with increased toxicity. Health-related quality of life (HRQoL) has become an important endpoint in clinical research to evaluate patients’ well-being in such a contradictory scenario. In this review, we examine key reported outcomes across clinical studies exploring HRQoL in patients with GEP-NETs. We have conducted a review of the literature using PubMed, The Cochrane Library, EMBASE, and Google Scholar. Selection criteria for articles were (1) publication in English between 1995 and 2014, (2) patients with GEP-NET, and (3) analysis of HRQoL, including mental health and psychological symptoms. Forty-nine studies met the inclusion criteria (31 clinical trials, 14 observational studies, and 4 developments of NET-specific HRQoL instruments). The scope and nature of the literature was diverse with 27 instruments used to measure aspects of HRQoL. EORTC QLQ-C30 was the most frequently used, in 38 of the 49 studies. Standardized measures revealed that in spite of generally good HRQoL, GEP-NET patients have specific psychological and physical complaints. The clinical benefit of somatostatin analogs and sunitinib has been clearly supported by HRQoL assessment. Improvement in HRQoL scores or symptom relief over time was also reported in 14 trials of peptide receptor radionuclide therapy, however the absence of randomized studies obviate definitive conclusions. We have also identified several unanswered questions that should be addressed in further research concerning chemotherapy, everolimus, surgery, local ablative therapies, and chemoembolization. Future research should incorporate GEP-NET-specific HRQoL instruments into phase III trials. This review may help both clinicians and researchers to select the most appropriate tools to assess changes in HRQoL in this population.This project was funded in part by a restricted educational grant from Novartis Spain and by support from the Spanish Neuroendocrine Tumor Group (GETNE).Peer Reviewe

    Is trivial the antiferromagnetic RP(2) model in four dimensions?

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    We study the antiferromagnetic RP(2) model in four dimensions. We find a second order transition with two order parameters, one ferromagnetic and the other antiferromagnetic. The antiferromagnetic sector has mean-field critical exponents and a renormalized coupling which goes to zero in the continuum limit. The exponents of the ferromagnetic channel are not the mean-field ones, but the difference can be interpreted as logarithmic corrections. We perform a detailed analysis of these corrections and conclude the triviality of the continuum limit of this model.Comment: 21 pages, 5 figures, LaTeX2

    The three-dimensional randomly dilute Ising model: Monte Carlo results

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    We perform a high-statistics simulation of the three-dimensional randomly dilute Ising model on cubic lattices L3L^3 with L256L\le 256. We choose a particular value of the density, x=0.8, for which the leading scaling corrections are suppressed. We determine the critical exponents, obtaining ν=0.683(3)\nu = 0.683(3), η=0.035(2)\eta = 0.035(2), β=0.3535(17)\beta = 0.3535(17), and α=0.049(9)\alpha = -0.049(9), in agreement with previous numerical simulations. We also estimate numerically the fixed-point values of the four-point zero-momentum couplings that are used in field-theoretical fixed-dimension studies. Although these results somewhat differ from those obtained using perturbative field theory, the field-theoretical estimates of the critical exponents do not change significantly if the Monte Carlo result for the fixed point is used. Finally, we determine the six-point zero-momentum couplings, relevant for the small-magnetization expansion of the equation of state, and the invariant amplitude ratio Rξ+R^+_\xi that expresses the universality of the free-energy density per correlation volume. We find Rξ+=0.2885(15)R^+_\xi = 0.2885(15).Comment: 34 pages, 7 figs, few correction

    Recensiones [Revista de Historia Económica Año XV Otoño-Invierno 1997 n. 3 pp. 637-673]

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    Editada en la Fundación Empresa PúblicaDavid S. Reher. La familia en España, pasado y presenta (Por Enriqueta Camps Cura).-- Juan A. Sánchez Belén. La política fiscal en Castilla durante el reinado de Carlos V (Por Francisco Comín).-- José Marchena. Burgueses y caciques en el Cádiz de la Restauración (Por Carlos Larrinaga).-- G. Pérez Sánchez. Ser trabajador; vida y respuesta obrera (Valladolid 1875-1931) (Por Esmeralda Ballesteros Doncel).-- María Teresa Pérez Picazo. Historia de España del siglo XX (Por Antonio Escudero).-- Virginia García Acosta (coord.). Los precios de alimentos y manufacturas novohispanos (Por Juan Carlos Sola Corbacho).-- Roberto Cortés Conde. La economía argentina en el largo plazo (Por Isabel Sanz Vülarroya).-- Philip Hoffmam. Growth in a Traditional Society (Por Juan Antonio Carmona Pidal).-- Michael Huberman. Escape from the market. Negotiating work in Lancashire (Por Joan R. Roses).-- Jean-Michel Selig. Malnutrition & dévelopment économique dans l'Alsace duxix siécle (Por José Miguel Martínez Carrión).-- R. M. Hartwell. A History of the Mont Pelerin Society (Por Carlos Rodríguez Braun).-- N. Crafts and G. Toniolo. Economic growth in Europe since 1945 (Por DouglasJ. Forsyth).-- Jaime Reis. O Banco de Portugal das Origens a 1914. I Volume: Antecedentes. Fundafao. Consolidagao (1821-1857) (Por Pablo Martín Aceña)Publicad

    The systemic lupus erythematosus IRF5 risk haplotype is associated with systemic sclerosis

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    Systemic sclerosis (SSc) is a fibrotic autoimmune disease in which the genetic component plays an important role. One of the strongest SSc association signals outside the human leukocyte antigen (HLA) region corresponds to interferon (IFN) regulatory factor 5 (IRF5), a major regulator of the type I IFN pathway. In this study we aimed to evaluate whether three different haplotypic blocks within this locus, which have been shown to alter the protein function influencing systemic lupus erythematosus (SLE) susceptibility, are involved in SSc susceptibility and clinical phenotypes. For that purpose, we genotyped one representative single-nucleotide polymorphism (SNP) of each block (rs10488631, rs2004640, and rs4728142) in a total of 3,361 SSc patients and 4,012 unaffected controls of Caucasian origin from Spain, Germany, The Netherlands, Italy and United Kingdom. A meta-analysis of the allele frequencies was performed to analyse the overall effect of these IRF5 genetic variants on SSc. Allelic combination and dependency tests were also carried out. The three SNPs showed strong associations with the global disease (rs4728142: P = 1.34×10<sup>−8</sup>, OR = 1.22, CI 95% = 1.14–1.30; rs2004640: P = 4.60×10<sup>−7</sup>, OR = 0.84, CI 95% = 0.78–0.90; rs10488631: P = 7.53×10<sup>−20</sup>, OR = 1.63, CI 95% = 1.47–1.81). However, the association of rs2004640 with SSc was not independent of rs4728142 (conditioned P = 0.598). The haplotype containing the risk alleles (rs4728142*A-rs2004640*T-rs10488631*C: P = 9.04×10<sup>−22</sup>, OR = 1.75, CI 95% = 1.56–1.97) better explained the observed association (likelihood P-value = 1.48×10<sup>−4</sup>), suggesting an additive effect of the three haplotypic blocks. No statistical significance was observed in the comparisons amongst SSc patients with and without the main clinical characteristics. Our data clearly indicate that the SLE risk haplotype also influences SSc predisposition, and that this association is not sub-phenotype-specific
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