Fast and broadband fiber dispersion measurement with dense wavelength sampling

We report on a method to obtain dispersion measurements from spectral-domain low-coherence interferograms which enables high accuracy (~ps/(nm·km)), broadband measurements and the determination of very dense (up to 20 points/nm over 500 nm) data sets for both dispersion and dispersion slope. The method exploits a novel phase extraction algorithm which allows the phase associated with each sampling point of the interferogram to be calculated and provides for very accurate results as well as a fast measurement capability, enabling close to real time measurements. The important issue of mitigating the measurement errors due to any residual dispersion of optical elements and to environmental fluctuations was also addressed. We performed systematic measurements on standard fibers which illustrate the accuracy and precision of the technique, and we demonstrated its general applicability to challenging problems by measuring a carefully selected set of microstructured fibers: a lead silicate W-type fiber with a flat, near-zero dispersion profile; a hollow core photonic bandgap fiber with strongly wavelength dependent dispersion and dispersion slope; a small core, highly birefringent index guiding microstructured fiber, for which polarization resolved measurements over an exceptionally wide (~1000 nm) wavelength interval were obtained

Buildings as a seismic source: analysis of a release test at Bagnoli, Italy

Taking advantage of a large displacement-release experiment on a twostory reinforced concrete building located in Bagnoli (Naples, Italy), we performed free-field measurements using 3D seismometers, accelerometers, and a 100-m-long vertical array. The ground motion was noticeable: near the building, the acceleration exceeded 5% g. At each measurement point, it was possible to recognize two source terms, due to the tested building and to the reaction structure. The two sources generated different wave trains. High-frequency accelerations propagated as Rayleigh waves, whereas 1–2 Hz waves carrying most of the displacement propagated only as body waves. The experiment lends further support to the hypothesis that buildings are able to modify substantially the free-field ground motion in their proximity: the peak ground acceleration we observed is the 20% of the ground acceleration required to produce a displacement on the building equal to the one imposed during the release test. We recognize, however, the difficulty of a realistic modeling of wave propagation in the topmost layer of a densely urbanized area

Intramedullary craniovertebral junction metastasis leading to the diagnosis of underlying renal cell carcinoma

Background: Intramedullary spinal cord metastases represent 4–8.5% of the central nervous system metastases and affect only 0.1–0.4% of all patients. Those originating from renal cell carcinoma (RCC) are extremely rare. Of the eight patients described in the literature with metastatic RCC and intramedullary cord lesion, only five were found in the cervical spine. Here, the authors add a 6th case involving an RCC intramedullary metastasis at the C1–C2 level. Case Description: A 78-year-old male patient presented with intermittent cervicalgia of 5 months duration accompanied by few weeks of a progressive severe right hemiparesis, up to hemiplegia. The magnetic resonance imaging (MRI) examination revealed an intramedullary expansive lesion measuring 10 mm×15 mm at the C1–C2 level; it readily enhanced with contrast. A total body computed tomography (CT) scan documented an 85 mm mass involving the right kidney, extending to the ipsilateral adrenal gland, and posteriorly infiltrating the ipsilateral psoas muscle. The subsequent CT-guided fine-needle biopsy confirmed the diagnosis of an RCC (Stage IV). The patient next underwent total surgical total removal of the C1–C2 intramedullary mass, following which he exhibited a slight motor improvement, with the right hemiparesis (2/5). He died after 14 months due to global RCC tumor progression. Conclusion: The present case highlights that a patient without a prior known diagnosis of RCC may present with an intramedullary C1–C2 metastasis. In such cases, global staging is critical to determine whether primary lesion resection versus excision of metastases (e.g., in this case, the C1–C2 intramedullary tumor) are warrante

Pruebas Empíricas con Empresas que Realizan Oferta Pública de sus Acciones en los Mercados de Valores de Argentina, Chile, Brasil, México, Colombia, Perú, Venezuela, y Estados Unidos.

CAPÍTULO I INTRODUCCIÓN TEÓRICA - Introducción - Formulación del problema - Marco teórico - Introducción - Modelo CAPM -Estado actual del conocimiento - Objetivos - Objetivo general - Objetivos específicos - Hipótesis - Presupuestos aceptados - Hipótesis a verificar - Universo de análisis - Metodología - Recopilación de Datos - Cálculo de los Betas Bursátiles - Cálculo de los Betas Contables - Estudio de la significación estadística de los coeficientes betas - Determinación del grado de asociación de las variables de objeto de estudio - Análisis de significación de los coeficientes de correlación - Resultados esperados - CAPÍTULO II DETERMINACIÓN DEL GRADO DE ASOCIACIÓN ENTRE BETAS CONTABLES Y BETAS DE MERCADO DE EMPRESAS ARGENTINAS QUE REALIZAN OFERTA PÚBLICA DE SUS ACCIONES EN LA B.C.B.A. - Introducción - Universo de análisis - Descripción y características de los datos utilizados - Fundamentación del período de estudio seleccionado - Herramientas cuantitativas empleadas - Interpretación de las variables que surgen de la regresión - Determinación de la asociación entre betas contables y betas bursátiles - Análisis de significación de los coeficientes de correlación - Análisis empírico - Betas de mercado - Cartera de mercado - Cálculo de betas de mercado - Resumen de los betas bursátiles de las compañías que cotizan en la BCBA - Betas contables base ROE - Cartera de mercado estimada con datos contables - Cálculo de betas contables - Resumen de los betas contables de las compañías que cotizan en la BCBA - Betas contables base utilidad bruta Cartera de mercado estimada con datos contables - Cálculo de betas contables - Resumen de los betas contables de las compañías que cotizan en la BCBA - Análisis de correlación entre betas contables (Base ROE) y betas bursátiles - Determinación del grado de significación de la asociación entre betas contables (Base ROE) y betas de mercado - Análisis de correlación entre betas contables (Base Utilidad Bruta) y betas bursátiles - Determinación del grado de significación de la asociación entre betas contables (Base Utilidad Bruta) y betas de mercado - Resumen del capítulo II - CAPÍTULO III ESTUDIO DE BETAS SECTORIALES EXTRANJEROS ANÁLISIS EMPÍRICO CON EMPRESAS QUE REALIZAN OFERTA PÚBLICA DE SUS ACCIONES EN LA BCBA, EN LA BCS, EN EL BOVESPA, EN LA BMV, EN LA BVC (Colombia), EN LA BVL, EN LA BVC (Caracas), EN LA NASDAQ, Y EN LA NYSE - Introducción - Descripción y características de los datos utilizados - Universo de análisis - Fundamentación del período de estudio seleccionado - Herramientas cuantitativas empleadas - Determinación de la asociación entre betas sectoriales argentinos y betas sectoriales extranjeros - Análisis de significación de los coeficientes de correlación - Análisis empírico - Cálculo de betas sectoriales - Análisis de betas sectoriales apalancados - Betas sectoriales apalancados (Argentina – Chile) - Betas sectoriales apalancados (Argentina – Brasil) - Betas sectoriales apalancados (Argentina – México) - Betas sectoriales apalancados (Argentina – Colombia) - Betas sectoriales apalancados (Argentina – Perú) - Betas sectoriales apalancados (Argentina – Venezuela) - Betas sectoriales apalancados (BCBA – NASDAQ) - Betas sectoriales apalancados (BCBA – NYSE) - Análisis de betas sectoriales desapalancados - Betas sectoriales desapalancados (Argentina – Chile) - Betas sectoriales desapalancados (Argentina – Brasil) - Betas sectoriales desapalancados (Argentina – México) - Betas sectoriales desapalancados (Argentina – Colombia) - Betas sectoriales desapalancados (Argentina – Perú) - Betas sectoriales desapalancados (Argentina – Venezuela) - Betas sectoriales desapalancados (BCBA – NASDAQ) - Betas sectoriales desapalancados (BCBA – NYSE) - Análisis de significación entre betas sectoriales argentinos y extranjeros - Análisis de correlación parcial entre betas sectoriales argentinos y extranjeros - Análisis del efecto tamaño de la empresa en el rendimiento requerido al capital propio - Resumen del capítulo III - Conclusiones generales - Bibliografía - Anexo I - Anexo II - Anexo III - Anexo IVEl presente trabajo pretende determinar una metodología de trabajo para estimar el riesgo de mercado en empresas argentinas que no disponen de la cotización bursátil de sus acciones. Para ello se evalúa las distintas alternativas de cálculo a través del uso de herramientas estadísticas. Se investiga la significación estadística del grado de correlación entre los betas contables y los betas bursátiles de las compañías que realizan oferta pública de sus acciones en la Bolsa de Comercio de Buenos Aires. También se analiza la significación estadística del grado de asociación entre los betas sectoriales de Argentina, con los betas sectoriales de Chile, Brasil, Estados Unidos, México, Perú, Colombia y Venezuela.Fil: Ponzo Florimonte., Rafael M. Universidad Nacional de Córdoba. Facultad de Ciencias Económicas; Argentina

Nutritional interventions for patients with melanoma: From prevention to therapy—an update

Melanoma is an aggressive skin cancer, whose incidence rates have increased over the past few decades. Risk factors for melanoma are both intrinsic (genetic and familiar predisposition) and extrinsic (environment, including sun exposure, and lifestyle). The recent advent of targeted and immune-based therapies has revolutionized the treatment of melanoma, and research is focusing on strategies to optimize them. Obesity is an established risk factor for several cancer types, but its possible role in the etiology of melanoma is controversial. Body mass index, body surface area, and height have been related to the risk for cutaneous melanoma, although an ‘obesity paradox’ has been described too. Increasing evidence suggests the role of nutritional factors in the prevention and management of melanoma. Several studies have demonstrated the impact of dietary attitudes, specific foods, and nutrients both on the risk for melanoma and on the progression of the disease, via the effects on the oncological treatments. The aim of this narrative review was to summarize the main literature results regarding the preventive and therapeutic role of nutritional schemes, specific foods, and nutrients on melanoma incidence and progression

Effects of resveratrol on bone health in type 2 diabetic patients. A double-blind randomized-controlled trial

Abstract Objectives Patients with type 2 diabetes (T2DM) are at increased fracture risk. Resveratrol has shown beneficial effects on bone health in few studies. The aim of this trial was to investigate the effects of resveratrol on bone mineral density (BMD) and on calcium metabolism biomarkers in T2DM patients. Methods In this double-blind randomized placebo-controlled trial 192 T2DM outpatients were randomized to receive resveratrol 500 mg/day (Resv500 arm), resveratrol 40 mg/day (Resv40 arm) or placebo for 6 months. BMD, bone mineral content (BMC), serum calcium, phosphorus, alkaline phosphatase, and 25-hydroxy vitamin D were measured at baseline and after 6 months. Results At follow-up, calcium concentrations increased in all patients, while within-group variations in alkaline phosphatase were higher in both resveratrol arms, and 25-hydroxy vitamin D increased in the Resv500 arm only, without between-group differences. Whole-body BMD significantly decreased in the placebo group, while whole-body BMC decreased in both the placebo and Resv40 arms. No significant changes in BMD and BMC values occurred in the Resv500 arm. The adjusted mean differences of change from baseline were significantly different in the Resv500 arm vs placebo for whole-body BMD (0.01 vs −0.03 g/cm2, p = 0.001), whole-body BMC (4.04 vs −58.8 g, p < 0.001), whole-body T-score (0.15 vs −0.26), and serum phosphorus (0.07 vs −0.01 µmol/L, p = 0.002). In subgroup analyses, in Resv500 treated-patients BMD values increased to higher levels in those with lower calcium and 25-hydroxy vitamin D values, and in alcohol drinkers. Conclusions Supplementation with 500 mg resveratrol prevented bone density loss in patients with T2DM, in particular, in those with unfavorable conditions at baseline