208 research outputs found
The first black hole orbiting a Be star
Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2016, Tutor: Marc Ribó GomisStellar-mass black holes have been discovered in binary systems. The study of radial velocities of the
companion stars allows us to restrict the masses of the compact objects. The Be/Compact Object binary system MWC 656 (also known as HD 215227) shows Fe II 4583Å and He II 4686Å emission lines (both double-peaked) on its spectrum. These lines indicate the existence of disks surrounding the binary components. Through the analysis of the radial velocities of He II (formed in the surrounding gas of the compact object) and Fe II (formed in the circumstellar disk around the Be star) emission lines using the SBOP program, the existence of a compact object with a mass in the range of 3.7 to 6.9 solar masses (within errors) is proved. As the lower value of the mass of the compact object is above the Tolman-Oppenheimer-Volkoff limit (3 solar masses), the Be star companion is classified as a black hole. Around 80 Be X-ray binaries have been found up to now. All but MWC 656 are supposed to be Be/Neutron star systems. For this reason, MWC 656 has been considered the first binary system consisting of a Be star and a black hole. Finally, the difficulty of detecting these Be/Black hole binaries through X-ray surveys is explained thanks to the study of black holes state
Evaluating by LCA the environmental impact savings related to the use of waste incineration bottom ash in porcelain tiles manufacturing: The role of metals recovery
The implementation of circular economy concepts in industrial manufacturing is being promoted in many Countries, in particular by the EU. The evaluation of the economic and environmental savings related to the decrease of the amounts of waste sent to final disposal and also of the impacts of the extraction of raw materials, are of particular relevance to companies. In particular, Life Cycle Assessment (LCA) and footprint analysis are being increasingly applied with the aim of attaining Environmental Product Declarations (EPDs) to prove to potential customers how “greener” the products achieved employing circular routes are compared to those attained via traditional linear processes. It should be noted however, that the environmental advantages that can be achieved can vary significantly according to the specific characteristics of the system in question, such as the current strategies applied for managing the waste, the types and amounts of raw materials that are replaced and the distance of supply of each type of material (both for the waste and raw materials). A type of waste material that is currently being increasingly used outside of landfills is waste incineration bottom ash. This material is employed as aggregates or sand substitutes in concrete or asphalt mixtures, as aggregates in unbound applications, or as raw material in cement or recently also ceramics manufacturing. In any case, the bottom ash is first treated to recover ferrous and non-ferrous metals and may undergo different treatments such as particle size separation, crushing, washing, natural weathering and/or binder addition, in view of the intended application. In this study, we focused on the relevance of some of the input parameters and assumptions on the environmental impacts resulting for a cradle to gate LCA case study concerning a manufacturing process employing waste incineration bottom ash. Specifically, data from a company in Central Italy that has started a production line of porcelain stoneware tiles using waste incineration bottom ash in partial replacement of feldspar sands was employed to evaluate the environmental impacts related to the manufacturing of the new product, comparing them to those of the same type of tiles produced using only quarried material. From the comparison of the environmental performances related to the production of the two types of products (stoneware tiles with and without bottom ash) assessed employing the EPD 2018 method and Simapro 9.1.1 software, the production of the tile containing the bottom ash compared to that obtained by the traditional process would in particular involve a significant decrease of the following impacts: mineral consumption and eutrophication (70%), photochemical smog and acidification (40-45%) and climate change (25%). In particular, the results showed that the reduction of the impacts is not so much linked to the impacts avoided for the extraction and transport of feldspar replaced by bottom ash, as to the recovery of ferrous and non-ferrous metals from the bottom ash implemented in the tiles manufacturing plant. It is evident hence that the results are strongly dependent on the assumptions made regarding the amounts of iron and aluminum that can be recovered and the processes assumed for their recovery. In particular, the substitution of primary steel and aluminum production were considered, although the impacts related to secondary steel and aluminum production were accounted for and substitution ratios lower than 1 were considered. It should be highlighted that for the analyzed case study it was considered that the bottom ash would be treated for metal recovery at the plant and would be diverted from landfills. If instead pre-treated bottom ash intended for reuse as aggregates were employed in the tile production process, the potential environmental benefits that could be achieved would be significantly lower. At the Conference the results of the study, and in particular the effects of the assumptions made on ferrous and non-ferrous metals recovery, with regard to amounts, quality and utilization/substitution scenarios, as well as of the management options for the bottom ash and transport distances, will be assessed in terms of their overall effect on the environmental impact savings of the examined circular economy process
Volatilización de NH3 de fertilizantes nitrogenados aplicados en superficie como urea y clinoptilolita-NH4 en 2 suelos de textura arenosa
Teniendo en cuento el reciente descubrimiento de importantes yacimientos de minerales zeolíticos en nuestro país, se plantea la hipótesis de que el aporte de nitrógeno al suelo con soporte clinoptilolita, permitirá disminuir la volatilización de amonio, en relación a la urea, cuando se aplica superficialmente, aumentando la eficiencia de uso del fertilizante. El objetivo de este trabajo es evaluar las perdidas por volatilización de NH3 proveniente de dos fuentes de fertilizante nitrogenado, urea y clinoptilolita –NH4, en 2 suelos de textura gruesa con caracteristicas fisicoquímicas variables. Se pretende brindar pautas tecnológicas de su empleo como alternativa a técnicas tradicionales de fertilización.Eje: Ingeniería agrícolaFacultad de Ciencias Agrarias y Forestale
Lesões pancreáticas em Doença de Chagas aguda experimental
BACKGROUND: Chagas' disease is an endemic tropical affliction found from southern United States to Argentina. The acute phase of this disease is difficult to study in man because the symptoms are non-specific and most cases require no medical assistance. Experimental models have been developed for sequential studies, and intense parasitism in all organs and tissues, including the pancreas, have been detected in the acute phase. PURPOSE: To evaluate the involvement of the pancreas in acute experimental Chagas' disease in a mouse model by histopathological characterization. CASUISTIC AND METHODS: Ten BALBc mice, about 20 g, injected i.p. with 100 000 forms of the Y strain of Trypanosoma cruzi were used. The animals were sacrificed after 14 days of infection. Fragments of pancreas were processed by conventional paraffin embedding and hematoxylin-eosin staining. RESULTS: Ruptured pseudocysts and release of parasites to the extracellular medium caused by necrosis of acinar and duct cells and foci of fat were the most striking histopathological features of acute Chagasic pancreatitis. CONCLUSION: Parasitism is the main cause of acute pancreatitis in Chagas' disease.INTRODUÇÃO: A Doença de Chagas é uma endemia tropical encontrada desde o sul dos Estados Unidos até a Argentina. Os estudos de fase aguda da doença são difíceis de serem realizados em seres humanos porque os sintomas são inespecíficos e a maioria dos casos não requer socorro médico. Em modelos experimentais desenvolvidos a doença aguda aparece com intenso parasitismo em todos os órgãos e tecidos. OBJETIVO: Caracterizar histopatologicamente o envolvimento pancreático na Doença de Chagas aguda experimental. CASUÍSTICA E MÉTODOS: Com esta finalidade utilizamos animais inoculados intraperitonialmente com 100.000 formas de cepa Y de Trypanosoma cruzi. Os animais foram sacrificados após 14 dias de infecção e os fragmentos colhidos foram processados em parafina e corados pela H&E. RESULTADOS: As características histopatológicas mais importantes da pancreatite aguda na Doença de Chagas experimental são: pseudocistos intensamente parasitados, íntegros ou rompidos, parasitas no espaço extracelular, necrose de células acinares e ductais, além de focos de esteatonecrose. CONCLUSÃO: O parasitismo dos tecidos é o principal mecanismo patogenético da pancreatite aguda na Doença de Chagas
Use of clinoptilolite as a carrier for nitrogen fertilizers in soils of the Pampean regions of Argentina
The properties of clinoptilolite related to cationic exchange and ionic selectivity have motivated us to study its application for agronomic purposes. The high potential of the clinoptilolite has been demonstrated as a vehicle for nitrogen fertilizers, with the aims of decreasing negative impacts on the environment and increasing fertilizer efficiency.
The objective of this study was to evaluate the effects of an exchanged form, clinoptilolite- NH4, and an occluded form, clinoptilolite-urea, of nitrogen fertilizer relative to commercial urea on dry matter and the nitrogen uptake effi ciency of Lolium multifl orum under controlled conditions. Lolium multifl orum, sowed in a sandy loam soil, was fertilized with 0, 60, 120, and 180 kg·ha-1 of nitrogen. Yield increased considerably and nitrogen uptake effi ciency was enhanced when clinoptilolite-NH4 was used, possibly due to its ability to retain and slowly liberate NH4 + ions. This effect produces time differences in nitrogen disponibility in relation to urea, making the nitrogen available for a longer time for the plant. The clinoptilolite-urea treatments reduced yields signifi cantly in comparison with urea applications only at the lowest dose. In addition, the nitrogen uptake efficiency was always lower than the other treatments.Las propiedades relacionadas con el intercambio catiónico y la selectividad iónica que poseen las clinoptilolitas ha motivado el estudio de su aplicación en el ámbito agropecuario.
En trabajos previos se demostró una alta potencialidad de estos minerales como vehículo de fertilizantes nitrogenados, con la finalidad de disminuir problemas ambientales y aumentar la eficiencia de los fertilizantes. El objetivo de este trabajo fue evaluar la producción de materia seca y la recuperación de nitrógeno del fertilizante de un cultivo de Lolium multiflorum cv. Grandeza, fertilizado con clinoptilolita-NH4 (forma intercambiada), clinoptilolita-urea (forma ocluida) y urea granulada, mantenido en macetas en invernáculo. Se fertilizó en dosis equivalentes a 0, 60, 120 y 180 kg·ha-1 de nitrógeno y se evaluó el rendimiento de materia seca y la recuperación de nitrógeno del fertilizante a través del análisis de los cuatro cortes de L. multiflorum cv. Grandeza. Según los resultados obtenidos, la utilización de la clinoptilolita-NH4 produjo un aumento de rendimiento para todas las dosis de nitrógeno utilizadas. Asimismo, produjo un aumento en la eficiencia de recuperación del nitrógeno del fertilizante al emplear dosis de 120 y 180 kg·ha-1 de nitrógeno. La utilización de clinoptilolitaurea presentó menores rendimientos, estadísticamente significativos respecto de los tratamientos fertilizados con urea solo en la dosis menor. Asimismo, la eficiencia de recuperación del nitrógeno fue menor a la de los restantes tratamientos.Facultad de Ciencias Agrarias y Forestale
Lung anatomy, energy load, and ventilator-induced lung injury
High tidal volume can cause ventilator-induced lung injury (VILI), but positive end-expiratory pressure (PEEP) is thought to be protective. We aimed to find the volumetric VILI threshold and see whether PEEP is protective per se or indirectly
Predictivity of clinical, laboratory and imaging findings in diagnostic definition of palpable thyroid nodules. A multicenter prospective study
Abstract
PURPOSE:
To assess the role of clinical, biochemical, and morphological parameters, as added to cytology, for improving pre-surgical diagnosis of palpable thyroid nodules.
METHODS:
Patients with a palpable thyroid nodule were eligible if surgical intervention was indicated after a positive or suspicious for malignancy FNAC (TIR 4-5 according to the 2007 Italian SIAPEC-IAP classification), or two inconclusive FNAC at a 653 months interval, or a negative FNAC associated with one or more risk factor. Reference standard was histological malignancy diagnosis. Likelihood ratios of malignancy, sensitivity, specificity, negative (NPV), and positive predictive value (PPV) were described. Multiple correspondence analysis (MCA) and logistic regression were applied.
RESULTS:
Cancer was found in 433/902 (48%) patients. Considering TIR4-5 only as positive cytology, specificity, and PPV were high (94 and 91%) but sensitivity and NPV were low (61 and 72%); conversely, including TIR3 among positive, sensitivity and NPV were higher (88 and 82%) while specificity and PPV decreased (52 and 63%). Ultrasonographic size 653\u2009cm was independently associated with benignity among TIR2 cases (OR of malignancy 0.37, 95% CI 0.18-0.78). In TIR3 cases the hard consistency of small nodules was associated with malignity (OR: 3.51, 95% CI 1.84-6.70, p\u2009<\u20090.001), while size alone, irrespective of consistency, was not diagnostically informative. No other significant association was found in TIR2 and TIR3.
CONCLUSIONS:
The combination of cytology with clinical and ultrasonographic parameters may improve diagnostic definition of palpable thyroid nodules. However, the need for innovative diagnostic tools is still high
Is Dairy Effluent an Alternative for Maize Crop Fertigation in Semiarid Regions? An Approach to Agronomic and Environmental Effects
The reuse of effluents from intensive dairy farms combined with localized irrigation techniques (fertigation) has become a promising alternative to increase crop productivity while reducing the environmental impact of waste accumulation and industrial fertilizers production. Currently, the reuse of dairy effluents through fertigation by subsurface drip irrigation (SDI) systems is of vital importance for arid regions but it has been poorly studied. The present study aimed to assess the greenhouse gas (GHG) emissions, soil properties, and crop yield of a maize crop fertigated with either treated dairy effluent or dissolved granulated urea applied through an SDI system at a normalized N application rate of 200 kg N ha−1. Fertilizer application was divided into six fertigation events. GHG fluxes were measured during fertigation (62-day) using static chambers. Soil properties were measured previous to fertilizer applications and at the harvest coinciding with crop yield estimation. A slight increase in soil organic matter was observed in both treatments for the 20–60 cm soil depth. Both treatments also showed similar maize yields, but the dairy effluent increased net GHG emissions more than urea during the fertigation period. Nevertheless, the net GHG emissions from the dairy effluent were lower than the theoretical CO2eq emission that would have been emitted during urea manufacturing or the longer storage of the effluent if it had not been used, showing the need for life-cycle assessments. Local-specific emission factors for N2O were determined (0.07%), which were substantially lower than the default value (0.5%) of IPCC 2019. Thus, the subsurface drip irrigation systems can lead to low GHG emissions, although further studies are needed.EEA Hilario AscasubiFil: Lombardi, Banira. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina.Fil: Lombardi, Banira. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina.Fil: Orden, Luciano. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; ArgentinaFil: Orden, Luciano. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Varela, Patricio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; Argentina.Fil: Garay, Maximiliano. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Iocoli, Gastón Alejandro. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Montenegro, Agustín Rodrigo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; ArgentinaFil: Sáez-Tovar, José. Universidad Miguel Hernández. Centro de Investigación e Innovación Agroalimentaria y Agroambiental; EspañaFil: Bustamante, María Ángeles. Universidad Miguel Hernández. Centro de Investigación e Innovación Agroalimentaria y Agroambiental; EspañaFil: Juliarena, María Paula. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas; Argentina.Fil: Juliarena, María Paula. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina.Fil: Juliarena, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina.Fil: Moral, Raúl. Universidad Miguel Hernández. Centro de Investigación e Innovación Agroalimentaria y Agroambiental; Españ
Relationship between location and size of myocardial infarction and their reciprocal influences on post-infarction left ventricular remodeling
AimsTo assess the intricate relationship between myocardial infarction (MI) location and size and their reciprocal influences on post-infarction left ventricular (LV) remodelling.Methods and resultsA cohort of 260 reperfused ST-segment elevation MI patients was prospectively studied with cardiovascular magnetic resonance at 1 week (baseline) and 4 months (follow-up). Area at risk (AAR) and MI size were quantified by T2-weighted and late-gadolinium enhancement imaging, respectively. Adverse LV remodelling was defined as an increase in LV end-systolic volume ≥15 at follow-up. One hundred and twenty-seven (49) patients had anterior MI and 133 (51) patients had non-anterior MI. Although the degree of myocardial salvage was similar between groups (P=0.74), anterior MI patients had larger AAR and MI size than non-anterior MI patients yielding worse regional and global LV function at baseline and follow-up. At univariable analysis, anterior MI was associated with increased risk of adverse LV remodelling (P=0.017) and lower LV ejection fraction (EF) at follow-up (P=0.001), but not when accounted for baseline MI size. Accordingly, at multivariable analysis, baseline MI size but not its location was an independent predictor of adverse LV remodelling (odds ratio 1.061, P < 0.001) and EF at follow-up (β-coefficient=-0.255, P < 0.001).ConclusionAnterior MI patients experience more pronounced post-infarction LV remodelling and dysfunction than non-anterior MI patients due to a greater magnitude of irreversible ischaemic LV damage without any independent contribution of MI location. © 2011 The Author
Molecular targets and oxidative stress biomarkers in hepatocellular carcinoma: an overview
Hepatocellular carcinoma (HCC) is a complex and heterogeneous tumor with multiple genetic aberrations. Several molecular pathways involved in the regulation of proliferation and cell death are implicated in the hepatocarcinogenesis. The major etiological factors for HCC are both hepatitis B virus (HBV) and hepatitis C virus infection (HCV)
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