Analytic inference in finite population framework via resampling

The aim of this dissertation is to provide nonparametric tools for analytic inference on superpopulation models. To pursue the goal we approach to the problem in two different ways. The first one is analytic. Following the classical empirical process theory, we first derive a functional central limit theorem that fully characterizes the asymptotic distribution of the Hàjek estimator of the distribution function of the superpopulation. In addition, assuming some regularity conditions on the (superpopulation) parameters of interest, we extend this analytic characterization to a large class of possible paramaters of interest. The second one is more “practical”: our aim is to construct a computer intensive procedure that allows to infer the superpopulation, also when the (asymptotic) distribution of an interest parameter has an unmanageable analytic form. Clearly, such a procedure is resampling. Unfortunately, the most famous resampling technique, the bootstrap procedure, does not work in our framework. In fact, in the finite population framework, even if a superpopulation is assumed, the units cannot be assumed independent in the presence of a non trivial sampling design. This fact makes the classic bootstrap fail. Of course, in the survey sampling literature, resampling procedure have been proposed, but we haven not resort to them because of two reasons: i) a largest part of these resampling techniques have been developed to infer the finite population and not the superpopulation; ii) we want to make a parallel between the classical non parametric theory and survey sampling. Almost all of these procedures are justified by mimicking the first two moments of the distribution of the considered estimator, and this is not the argument used to justify Efron’s bootstrap in classical nonparametric statistics. Thus, we introduce the “ multinomial” scheme as a resampling procedure for the superpopulation and we provide an asymptotic validation of this method, that involves the whole distribution of the considered estimators, exactly as it happens for classic bootstrap. In the last part of this work, the results obtained are applied to different inferential problems and, for each one of the concerned problem, a simulation study is performed to test the validity of our proposal. For these applications, we especially focused on problems where the interest parameter is not a linear function of the data

On the estimation of the Lorenz curve under complex sampling designs

This paper focuses on the estimation of the concentration curve of a finite population, when data are collected according to a complex sampling design with different inclusion probabilities. A (design-based) Hajek type estimator for the Lorenz curve is proposed, and its asymptotic properties are studied. Then, a resampling scheme able to approximate the asymptotic law of the Lorenz curve estimator is constructed. Applications are given to the construction of (i) a confidence band for the Lorenz curve, (ii) confidence intervals for the Gini concentration ratio, and (iii) a test for Lorenz dominance. The merits of the proposed resampling procedure are evaluated through a simulation study

Phononic Graded Meta-MEMS for Elastic Wave Amplification and Filtering

Inspired by recent graded metamaterials designs, we create phononic arrays of micro-resonators for frequency signal amplification and wave filtering. Leveraging suspended waveguides on a thick silicon substrate, we hybridize surface Rayleigh and Lamb flexural waves to effectively achieve phononic signal control along predefined channels. The guided waves are then spatially controlled using a suitable grading of the micro-resonators, which provide high signal-to-noise ratio and simultaneously create phononic delay-lines. The proposed device can be used for sensing, wave filtering or energy harvesting

Distribution and 16S rDNA sequences of Argas monachus (Acari: Argasidae), a soft tick parasite of Myiopsitta monachus (Aves: Psittacidae)

Specimens of Argas monachus Keirans et al. were collected from Myiopsitta monachus nests in 42 localities in Argentina and Paraguay from 2006 to 2010. A list of localities where this tick has been found is presented. 16S rDNA sequences of specimens of A. monachus from different localities were compared to confirm whether they belong to the same specific taxon. Argas monachus is present in the phytogeographic provinces of Chaco, Espinal, and Monte, but not in the Pampa (all from de Chaco Domain) where the host is well distributed. No differences were found among 16S rDNA sequences of geographically distant specimens. © 2011 Springer Science+Business Media B.V.Fil: Mastropaolo, Mariano. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Turienzo, Paola Noemí. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Iorio, Osvaldo Rubén. Universidad de Buenos Aires; ArgentinaFil: Nava, Santiago. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Venzal, José Manuel. Universidad de la República; UruguayFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

3-D Fibrin Scaffold Improves Stemness of Human Peripheral Blood Endothelial Progenitor Cells

Aims Fibrin is a natural biopolymer appealing for cell-based regenerative therapies, because it can support growth, migration and differentiation of different cell types. Endothelial progenitor cells (EPC) represent a very interesting alternative cell source for mature endothelial cells; the fact that can easily isolated from the peripheral blood, thereby eliminating donor morbidity, makes them ideal in applications in the field of regenerative medicine. We have demonstrated that fibrin can support EPC viability and growth. Aim of this study was to evaluate if fibrin can affect EPC differentiation and stem cell markers expression. Methods Fibrin was prepared mixing commercially available (Kedrion S.p.A. Lucca, Italy) fibrinogen (9 mg/ml) and thrombin (25 U/ml). Clot ultrastructure was investigated by scanning electron microscopy (SEM) and cryogenic SEM (CRYO-SEM) to measure fibre diameter and density. Clot elasticity was evaluated by atomic force microscopy (AFM), measuring the tip-sample force by cantilever displacement. EPC were obtained from peripheral blood and cultured on fibrin at the concentration of 1x106cell/cm2. Fibronectin coating was used as a control. Metabolic activity was assessed after 7 and 14 days by WST1 assay and viability by confocal microscopy (calcein incorporation). The expression of both endothelial (CD31, KDR, vWF, Ve-Cadherin) and stem cell markers (nanog, oct-4) was assessed by flow cytometry, confocal microscopy and Real Time RT-PCR. Results SEM analysis revealed a nanometric fibrous structure, with mean fiber diameter of 165?4 nm and mean density of 95.9?0.2 %. CRYO-SEM suggested a reticulate structure with mesh-size up to 10 ?m. Fibrin clot elasticity was 1.78 MPa, as in literature. WST1 assay showed that fibrin increased EPC metabolic activity as compared to fibronectin (fibrin: 0.606?0.056 a.u. vs. fibronectin: 0.311?0.067). Calcein staining demonstrated that EPC were still viable at 14 days. Flow cytometry showed the expression of endothelial markers (CD31=41.8?8.4%; vWF=32.3?3.0%; KDR=89.3?3.7%; VE-Cadherin=41.2?3.8%), confirmed also by confocal microscopy and Real Time RT-PCR. Interestingly, nanog and oct-4 (embryonic stem cell markers) expression was significantly greater on fibrin (p<0.001) as compared to fibronectin. Conclusions These findings suggest that fibrin it is not only a suitable scaffold for EPC growth and viability but also induces EPC differentiation. The observation that Nanog, known as the most important marker of stemness, is maintained longer than on fibronectin, may offer a surplus value to stem cell-based therapies

Evaluación de las condiciones del cuidado doméstico y extradoméstico, estado nutricional y desarrollo infantil en el distrito de Ensenada

Se presentan resultados parciales del proyecto Evaluación de las condiciones del cuidado doméstico y extradoméstico, estado nutricional y desarrollo infantil en Berisso y Ensenada (PFCCIC 2016), cuyo objetivo es contribuir al cono-cimiento de las vinculaciones entre los factores ambientales no naturales (domésticos y extradomésticos) y algunos indicadores de la salud infantil, en distritos de la provincia de Buenos Aires. El proyecto asume: a) un diseño transeccional correlacional a partir de una muestra probabilística polietápica, estratificada por conglomerados, con selección de escuelas de nivel inicial –y secciones de 5 años– del ámbito público, de forma aleatoria proporcional; y b) una estrategia de triangulación intrametodológica con uso de encuestas semiestructuradas, autoadministradas a padres/madres, mediciones antropométricas y evaluación del desarrollo psicológico de todos/as los/as niños/as de las secciones seleccionadas, con consentimiento informado. Los resultados que se presentan aquí son los obtenidos para el municipio de Ensenada. Son un aporte a la evaluación de las condiciones del cuidado –doméstico y extradoméstico–, el estado nutricional y el desarrollo infantil en niños/as que asisten al nivel inicial de escuelas públicas, y se espera que representen un insumo valioso destinado a orientar acciones dirigidas a resolver problemáticas extendidas en la infancia.Trabajo presentado por el Centro de Estudios en Nutrición y Desarrollo Infantil (CEREN

Evaluación de las condiciones del cuidado doméstico y extradoméstico, estado nutricional y desarrollo infantil en el distrito de Ensenada

Se presentan resultados parciales del proyecto Evaluación de las condiciones del cuidado doméstico y extradoméstico, estado nutricional y desarrollo infantil en Berisso y Ensenada (PFCCIC 2016), cuyo objetivo es contribuir al cono-cimiento de las vinculaciones entre los factores ambientales no naturales (domésticos y extradomésticos) y algunos indicadores de la salud infantil, en distritos de la provincia de Buenos Aires. El proyecto asume: a) un diseño transeccional correlacional a partir de una muestra probabilística polietápica, estratificada por conglomerados, con selección de escuelas de nivel inicial –y secciones de 5 años– del ámbito público, de forma aleatoria proporcional; y b) una estrategia de triangulación intrametodológica con uso de encuestas semiestructuradas, autoadministradas a padres/madres, mediciones antropométricas y evaluación del desarrollo psicológico de todos/as los/as niños/as de las secciones seleccionadas, con consentimiento informado. Los resultados que se presentan aquí son los obtenidos para el municipio de Ensenada. Son un aporte a la evaluación de las condiciones del cuidado –doméstico y extradoméstico–, el estado nutricional y el desarrollo infantil en niños/as que asisten al nivel inicial de escuelas públicas, y se espera que representen un insumo valioso destinado a orientar acciones dirigidas a resolver problemáticas extendidas en la infancia.Trabajo presentado por el Centro de Estudios en Nutrición y Desarrollo Infantil (CEREN

How the First Year of the COVID-19 Pandemic Impacted Patients’ Hospital Admission and Care in the Vascular Surgery Divisions of the Southern Regions of the Italian Peninsula

Background: To investigate the effects of the COVID-19 lockdowns on the vasculopathic population. Methods: The Divisions of Vascular Surgery of the southern Italian peninsula joined this multicenter retrospective study. Each received a 13-point questionnaire investigating the hospitalization rate of vascular patients in the first 11 months of the COVID-19 pandemic and in the preceding 11 months. Results: 27 out of 29 Centers were enrolled. April-December 2020 (7092 patients) vs. 2019 (9161 patients): post-EVAR surveillance, hospitalization for Rutherford category 3 peripheral arterial disease, and asymptomatic carotid stenosis revascularization significantly decreased (1484 (16.2%) vs. 1014 (14.3%), p = 0.0009; 1401 (15.29%) vs. 959 (13.52%), p = 0.0006; and 1558 (17.01%) vs. 934 (13.17%), p &lt; 0.0001, respectively), while admissions for revascularization or major amputations for chronic limb-threatening ischemia and urgent revascularization for symptomatic carotid stenosis significantly increased (1204 (16.98%) vs. 1245 (13.59%), p &lt; 0.0001; 355 (5.01%) vs. 358 (3.91%), p = 0.0007; and 153 (2.16%) vs. 140 (1.53%), p = 0.0009, respectively). Conclusions: The suspension of elective procedures during the COVID-19 pandemic caused a significant reduction in post-EVAR surveillance, and in the hospitalization of asymptomatic carotid stenosis revascularization and Rutherford 3 peripheral arterial disease. Consequentially, we observed a significant increase in admissions for urgent revascularization for symptomatic carotid stenosis, as well as for revascularization or major amputations for chronic limb-threatening ischemia