392 research outputs found

    Existence of positive solutions for a semipositone p-Laplacian problem

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    We prove the existence of positive solutions to a semipositone p-Laplacian problem combining mountain pass arguments, comparison principles, regularity principles and a priori estimates

    The in-plane electrodynamics of the superconductivity in Bi2Sr2CaCu2O8+d: energy scales and spectral weight distribution

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    The in-plane infrared and visible (3 meV-3 eV) reflectivity of Bi2Sr2CaCu2O8+d (Bi-2212) thin films is measured between 300 K and 10 K for different doping levels with unprecedented accuracy. The optical conductivity is derived through an accurate fitting procedure. We study the transfer of spectral weight from finite energy into the superfluid as the system becomes superconducting. In the over-doped regime, the superfluid develops at the expense of states lying below 60 meV, a conventional energy of the order of a few times the superconducting gap. In the underdoped regime, spectral weight is removed from up to 2 eV, far beyond any conventional scale. The intraband spectral weight change between the normal and superconducting state, if analyzed in terms of a change of kinetic energy is ~1 meV. Compared to the condensation energy, this figure addresses the issue of a kinetic energy driven mechanism.Comment: 13 pages with 9 figures include

    PREVALENCE OF HUMAN ECHINOCOCCOSIS USING IMAGING TECHNIQUES IN YANAHUANCA, PASCO

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    El objetivo del estudio fue determinar la prevalencia de hidatidosis humana en nueve comunidades rurales del distrito de Yanahuanca, Pasco, empleando como técnicas de diagnóstico la ecografía abdominal y la radiografía de tórax. Además, se evaluó la asociación entre las variables edad, género y comunidad de procedencia y la presencia de pobladores positivos a quistes hidatídicos. La ecografía se realizó a 949 personas (52% de la población mayor de 5 años) y el examen radiográfico a 829 (45.6%). La prevalencia general de hidatidosis fue de 5.5% (52/949) con un intervalo de confianza al 95% de 4.1 a 7.1%. Se halló asociación estadística (p<0.05) entre edad con el resultado positivo al examen ecográfico, siendo las personas mayores de 40 años las que presentaron un mayor porcentaje. La relación de quistes hidatídicos hepáticos / pulmonares fue de 5.1. El 56% (25/45) de los quistes detectados por ecografía presentaron parcial o completa calcificación. La prevalencia obtenida es una de las más altas en Latinoamérica, posiblemente por la convivencia del poblador andino con el perro, dado su uso en el cuidado y pastoreo del ganado ovino, además de las deficientes condiciones higiénico-sanitarias, y bajos niveles socioeconómicos y culturales.The objective of this study was to determine the prevalence of human echinococcosis in nine communities of the district of Yanahuanca, Pasco, through abdominal echography and thorax radiography. In addition, the association between age, gender, and community with the disease was evaluated. Echographic examination was conducted in 949 persons (52% of the population over 5 years of age) and X ray test was performed in 829 (45.6%). The overall prevalence of human cystic echinococcosis was 5.5% (52/949) and the 95% confidence interval varied from 4.1 to 7.1%. There was statistical association (p<0.05) between age with positive results when using the ultrasound exam. The liver / lung hydatid cyst ratio was 5:1. Partial or total calcified cysts were detected by echographical examination (56%, 25/45). The prevalence of human hydatidosis in this endemic area of Peru is one of the highest in Latin America, possibly due to the close interaction with dogs, as they shepherd the flocks, plus poor sanitation and hygiene conditions in the area

    Associations between plasma neurofilament light, in vivo brain pathology, and cognition in non-demented individuals with autosomal-dominant Alzheimer's disease

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    BACKGROUND: Neurofilament light (NfL) is a promising biomarker of early neurodegeneration in Alzheimer's disease (AD). We examined whether plasma NfL was associated with in vivo amyloid beta and tau, and cognitive performance in non-demented presenilin-1 (PSEN1) E280A mutation carriers. METHODS: Twenty-five mutation carriers and 19 non-carriers (age range: 28 to 49 years) were included in this study. Participants underwent 11C Pittsburgh compound B (PiB)-PET (positron emission tomography), flortaucipir-PET, blood sampling, and cognitive testing. RESULTS: Mutation carriers exhibited higher plasma NfL levels than non-carriers. In carriers, higher NfL levels were related to greater regional tau burden and worse cognition, but not amyloid beta load. When we adjusted for age, a proxy of disease progression, elevated plasma NfL levels were only correlated with worse memory recall. CONCLUSIONS: Findings support an association between plasma NfL, cognition, and tau pathology in non-demented individuals at genetic risk for developing AD dementia. Plasma NfL may be useful for selecting individuals at increased risk and tracking disease progression in AD

    Phase 3 Trial of 177Lu-Dotatate for Midgut Neuroendocrine Tumors

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    Background Patients with advanced midgut neuroendocrine tumors who have had disease progression during first-line somatostatin analogue therapy have limited therapeutic options. This randomized, controlled trial evaluated the efficacy and safety of lutetium-177 (177Lu)-Dotatate in patients with advanced, progressive, somatostatin-receptor-positive midgut neuroendocrine tumors. Methods We randomly assigned 229 patients who had well-differentiated, metastatic midgut neuroendocrine tumors to receive either 177Lu-Dotatate (116 patients) at a dose of 7.4 GBq every 8 weeks (four intravenous infusions, plus best supportive care including octreotide long-acting repeatable [LAR] administered intramuscularly at a dose of 30 mg) (177Lu-Dotatate group) or octreotide LAR alone (113 patients) administered intramuscularly at a dose of 60 mg every 4 weeks (control group). The primary end point was progression-free survival. Secondary end points included the objective response rate, overall survival, safety, and the side-effect profile. The final analysis of overall survival will be conducted in the future as specified in the protocol; a prespecified interim analysis of overall survival was conducted and is reported here. Results At the data-cutoff date for the primary analysis, the estimated rate of progression-free survival at month 20 was 65.2% (95% confidence interval [CI], 50.0 to 76.8) in the 177Lu-Dotatate group and 10.8% (95% CI, 3.5 to 23.0) in the control group. The response rate was 18% in the 177Lu-Dotatate group versus 3% in the control group (P<0.001). In the planned interim analysis of overall survival, 14 deaths occurred in the 177Lu-Dotatate group and 26 in the control group (P=0.004). Grade 3 or 4 neutropenia, thrombocytopenia, and lymphopenia occurred in 1%, 2%, and 9%, respectively, of patients in the 177Lu-Dotatate group as compared with no patients in the control group, with no evidence of renal toxic effects during the observed time frame. Conclusions Treatment with 177Lu-Dotatate resulted in markedly longer progression-free survival and a significantly higher response rate than high-dose octreotide LAR among patients with advanced midgut neuroendocrine tumors. Preliminary evidence of an overall survival benefit was seen in an interim analysis; confirmation will be required in the planned final analysis. Clinically significant myelosuppression occurred in less than 10% of patients in the 177Lu-Dotatate group. (Funded by Advanced Accelerator Applications; NETTER-1 ClinicalTrials.gov number, NCT01578239 ; EudraCT number 2011-005049-11

    Software architecture for the measurement of operational risk in financial sector entities

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    La medición de los riesgos financieros tales como operacional, liquidez y crédito, entre otros, es una de las preocupaciones más frecuentes en el sector financiero; en este sentido, la materialización del riesgo operacional da lugar a enormes pérdidas monetarias derivadas de fallos en las personas, en los procesos y en los procedimientos que inciden en la operación de la entidad. Con el fin de sistematizar la medición del riesgo operacional se ha desarrollado el Sistema de Información Operational Risk Management, el cual facilita la medición del riesgo operacional, a partir de la obtención de la matriz de pérdidas esperadas e inesperadas y la estimación de Valor en Riesgo Operacional (Op-VaR) para los diferentes fallos que se puedan presentar en cada una de las líneas de negocio con las que cuenta la entidad. En este trabajo se muestra cómo el uso de la arquitectura basada en filtros facilita y agiliza cálculos que requieren grandes volúmenes de datos con información financiera. Actualmente el Sistema de Información es utilizado por entidades del sector financiero colombiano quienes a partir de su uso han optimizado tanto sus utilidades como la productividad del talento humano, toda vez que el sistema ha permitido generar planes de contingencia para atender una crisis por riesgo operacionalThe measurement of financial risks, such as operational, liquidity and credit, among others, is one of the most frequent concern in the bank and corporative sector, in this sense, the operational risk materialization causes large losses due to fails on the procedures that affect the functioning of the organization. With the goal of systematize the risk measurement, we has implement the Information System Financial Risk Management which facilitates the measurement of operational risk starting on the expected and unexpected loss matrix and the estimation of Value at Operational Risk (Op-VaR) for different failures that may occur in each of the business lines that the entity has. The paper shows how the use of filters based on easier and faster calculations that require large volumes of data from financial information architecture. Currently the Information System is used by Colombian financial sector entities who from their use have optimized both their profits and the productivity of human talent, since the system has allowed the generation of contingency plans to deal with a crisis due to operational ris

    La secuencia magmática Jurásico Superior-Cretácico Superior en la Cordillera Central, República Dominicana: sección cortical de un arco-isla intraoceánico.

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    The Late Jurassic-Late Cretaceous magmatic sequence exposed in the central-western sector of the Cordillera Central Dominican Republic, can be divided in five main lithostratigraphic units formed by plutonio, volcanic, volcanoclastic and sedimentary rocks. All rocks have suffered very heterogeneous ductile deformation and low-grade metamorphism with magmatic textures often preserved. From bottom to top, this magmatic sequence is made up of:: (1) Loma Caribe serpentinized peridotites, (2) the N-MORB volcano-plutonic assemblage of El Aguacate, of ophiolitic affinity, (3) the Duarte Complex oceanic plateau, (4) the arc-related volcanic and volcano-sedimentary sequence of the Tireo Formation, intruded by the Loma de Cabrera Batolith, and (5) the massive basaltic flows of Peña Blanca y Nalga de Maco. It is suggested that the magmatic sequence represents the crustal section of an intra-oceanic island arc, which was built onto a proto-caribbean oceanic crust and an overlying Lower Cretaceous oceanic plateau. The sequence is overlain by Upper Cretaceous basalts of the Caribbean oceanic plateau and limestones

    Pooling/bootstrap-based GWAS (pbGWAS) identifies new loci modifying the age of onset in PSEN1 p.Glu280Ala Alzheimer\u27s disease

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    The literature on GWAS (genome-wide association studies) data suggests that very large sample sizes (for example, 50,000 cases and 50,000 controls) may be required to detect significant associations of genomic regions for complex disorders such as Alzheimer\u27s disease (AD). Because of the challenges of obtaining such large cohorts, we describe here a novel sequential strategy that combines pooling of DNA and bootstrapping (pbGWAS) in order to significantly increase the statistical power and exponentially reduce expenses. We applied this method to a very homogeneous sample of patients belonging to a unique and clinically well-characterized multigenerational pedigree with one of the most severe forms of early onset AD, carrying the PSEN1 p.Glu280Ala mutation (often referred to as E280A mutation), which originated as a consequence of a founder effect. In this cohort, we identified novel loci genome-wide significantly associated as modifiers of the age of onset of AD (CD44, rs187116, P=1.29 _ 10?12; NPHP1, rs10173717, P=1.74 _ 10?12; CADPS2, rs3757536, P=1.54 _ 10?10; GREM2, rs12129547, P=1.69 _ 10?13, among others) as well as other loci known to be associated with AD. Regions identified by pbGWAS were confirmed by subsequent individual genotyping. The pbGWAS methodology and the genes it targeted could provide important insights in determining the genetic causes of AD and other complex conditions
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