Search results for "Statistic"

Statistical methods for the evaluation of university systems

2011

A note on (basic) Principal Components Analysis

2020

This paper provides some issues, known but somewhat little stressed, on using the conventional covariance or correlation matrix when performing the simple PCA. The paper also proposes a new simple alternative by providing some evidence, via real-data analysis and some simulation experiments, supporting the proposal

Il modulo elastico statico e dinamico del calcestruzzo

2012

Food Security Is None Of Your Business? Food Supply Chain Management In Support Of A Sustainable Food System

2017

Food security is the principal outcome of any given food system and it can be defined in terms of a sustainable food system where the core goal is to feed everyone sustainably, equitably and healthily. A sustainable food system addresses needs for availability, affordability and accessibility, is diverse, ecologically-sound and resilient, and builds the capabilities and skills necessary for future generations. This paper identifies the essential elements of food supply chain management in support of a sustainable food system, which ultimately enhances food security. The existing food supply chain and food system literature is synthesized in order to study the correspondence between public i…

L’emigrazione dei laureati dalla Sicilia: le più recenti evidenze statistiche

2008

Mapping a-priori defined plant associations using remotely sensed vegetation characteristics

2014

Abstract Incorporation of a priori defined plant associations into remote sensing products is a major challenge that has only recently been confronted by the remote sensing community. We present an approach to map the spatial distribution of such associations by using plant indicator values (IVs) for salinity, moisture and nutrients as an intermediate between spectral reflectance and association occurrences. For a 12 km 2 study site in the Netherlands, the relations between observed IVs at local vegetation plots and visible and near-infrared (VNIR) and short-wave infrared (SWIR) airborne reflectance data were modelled using Gaussian Process Regression (GPR) (R 2 0.73, 0.64 and 0.76 for sali…

Coarse-Graining Intermolecular Interactions in Dispersions of Highly Charged Colloids

2012

International audience; Effective pair potentials between charged colloids, obtained from Monte Carlo simulations of two single colloids in a closed cell at the primitive model level, are shown to reproduce accurately the structure of aqueous salt-free colloidal dispersions, as determined from full primitive model simulations by Linse et al. (Linse, P.; Lobaskin, V. Electrostatic Attraction and Phase Separation in Solutions of Like-Charged Colloidal Particles. Phys. Rev. Lett.1999, 83, 4208). Excellent agreement is obtained even when ion-ion correlations are important and is in principle not limited to spherical particles, providing a potential route to coarse-grained colloidal interactions…

Tooth size discrepancy in a Libyan population, a cross-sectional study in schoolchildren

2014

Objetives: The aim of this cross-sectional study was to investigate the tooth size discrepancy (TSD) in a group of Libyan schoolchildren, and to compare TSD between sexes. Material and Methods: The sample comprised 333 Libyan schoolchildren (162 males with a mean (SD) age of 14.4 (1.1) years, and 171 females with a mean age of 14.1 (1.1) years). Anterior and overall TSD ratios were computed using descriptive statistics. Sex differences were statistically assessed using an independent t-test ( P 0.05). The percentages of participants showing more than 2 SD variation for the anterior and overall ratios comprised 3% and 4.2% of the total sample, respectively. Conclusions: The anterior and over…

Cardiac changes in subclinical and overt hyperthyroid women: retrospective study

2003

This retrospective and descriptive 4-year study was undertaken to describe cardiac changes in subclinical and overt hyperthyroidism.We revised the charts of 386 consecutive cardiopathic women whose blood samples were referred to the Radioimmunoassay Laboratory to evaluate thyroid function from 1 January 1997 through 31 December 2000.After excluding women because euthyroid or hypothyroid, or taking amiodarone and women with hypertension, rheumatic disease, myocardial infarction, a total of 31 hyperthyroid women were thus selected for the study: 19 with subclinical hyperthyroidism and 12 with overt hyperthyroidism. The prevalence of atrial fibrillation did not differ between subclinical (48%)…

Ovarian size and blood flow in women with polycystic ovary syndrome (PCOS) and their correlations with some endocrine parameters

2005

Objective: To determine how common polycystic ovarian morphology may be in women given the clinical diagnosis of polycystic ovary syndrome (PCOS) based on chronic anovulation and hyperandrogenism and whether certain hormonal factors correlate with ovarian morphology and blood flow. Design: Prospective study. Setting: Two academic endocrinology centers in Italy. Patient(s): Three hundred twenty-six women with PCOS and 50 age-matched and weight-matched ovulatory women. Intervention(s): Ultrasound assessment of ovarian morphology in patients and controls and ovarian blood flow and fasting hormone levels in a subset of 50 patients and matched controls. Main Outcome Measure(s): Ovarian morpholog…