Search results for "parametric"
showing 10 items of 980 documents
Providing insights into browntail moth local outbreaks by combining life table data and semi-parametric statistics
2011
1. Life table studies have been an essential tool for the comprehension of insect population dynamics, although their use has been methodologically biased by a primary focus on mortality factors, especially natural enemies. Thus, studies in natural populations may relegate important mortality sources to the ‘unknown’ or ‘residual’ mortality categories. To overcome this limitation, life tables may be complemented by combining them with other approaches. 2. The aim of the present study was to provide insights into browntail moth Euproctis chrysorrhoea L. (Lepidoptera: Lymantriidae) local outbreaks by combining life table data and statistical modelling. First, E. chrysorrhoea population densit…
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…
Item Response Trees: a recommended method for analyzing categorical data in behavioral studies
2015
Behavioral data are notable for presenting challenges to their statistical analysis, often due to the difficulties in measuring behavior on a quantitative scale. Instead, a range of qualitative alternative responses is recorded. These can often be understood as the outcome of a sequence of binary decisions. For example, faced by a predator, an individual may decide to flee or stay. If it stays, it may decide to freeze or display a threat and if it displays a threat, it may choose from several alternative forms of display. Here we argue that instead of being analyzed using traditional nonparametric statistics or a series of separate analyses split by response categories, this kind of data ca…
Análisis y valoración de los sistemas de evaluación de suelos en España. Evolución, tendencias actuales y perspectivas futuras
1997
23 páginas, 5 cuadros.
Restituzioni omografiche di finte cupole: la cupola di Santa Maria dei Rimedi a Palermo
2016
Nel vasto repertorio siciliano delle prospettive solide, un ruolo di spicco è ricoperto da un esempio unico di realizzazione di finta prospettiva di cupola sferica su copertura ad arco ribassato, ricavata sull’incrocio del transetto con la navata centrale nella chiesa di Santa Maria dei Rimedi a Palermo. L’unicità di quest’opera sta nella geometria reale della cupola ribassata. Infatti gli esempi più diffusi di finte cupole in Sicilia sono realizzati su soffitti piani lignei o in calcestruzzo. In Appendice 1 si potrà consultare il repertorio delle finte cupole esistenti in Sicilia per la cui stesura ci si è avvalsi degli studi condotti dall’architetto Giuseppe Ingaglio nell’ambito della sua…
Elastīgais parametriskais modelis izdzīvošanas datiem ar konkurējošiem riskiem
2015
Konkurējošie riski ir izplatīta parādība izdzīvošanas analīzē. Tie rodas, kad subjekts atrodas vairāku savstarpēji izslēdzošu notikumu riska zonā. Populārākā metode, pētot šāda veida datus, ir Deivida Koksa semi-parametriskā modeļa izmantošana. Darbā ir aplūkots alternatīvais variants izdzīvošanas datiem ar konkurējošiem riskiem – elastīgais parametriskais modelis, kas sniedz gludus novērtējumus galvenajiem raksturlielumiem – konkrēto cēloņu riskam un kumulatīvo biežumu funkcijai. Turklāt, izmantojot šo modeli, ir viegli iekļaut no laika atkarīgus ietekmējošos mainīgos. Darbā tiek aprakstīta konkurējošo risku elastīgā parametriskā modeļa būtība, un metode ir salīdzināta ar Koksa modeli. Ir …
Functional principal component analysis of quantile curves
2017
Literature on functional data analysis is mainly focused on estimation of individuals curves and characterization of average dynamics. The idea underlying this proposal is to focus attention on other particular features of the distribution of the observed data, moving from mean functions towards functional quantiles. The motivating examples are functional data sets that are collections of high frequency data recorded along time. As quantiles provide information on various aspects of a time series, we propose a modelling framework for the joint estimation of functional quantiles, varying along time, and functional principal components, summarizing some common dynamics shared by the functiona…
Testing e validazione comparativa di coating idrofobizzanti per superfici in gelcoat
2021
Nell’industria delle telecomunicazioni a supporto del settore aerospaziale, il mantenimento dell’efficacia e della sicurezza delle trasmissioni in condizioni ambientali estreme assume un’importanza crescente, in funzione della sempre maggiore diffusione dei siti trasmittenti/riceventi, operativi su scala planetaria. In questa cornice, si richiede che gli elementi a protezione dei dispositivi installati si dimostrino durevoli nel tempo anche quando esposti ad abbondanti precipitazioni, accumuli nevosi continuati o stratificazioni di ghiaccio, e improvvisi shock termici, garantendo nel contempo la fedeltà della trasmissione. Una marcata idrofobicità degli strati esterni delle coperture risult…
Inequality of Spanish household expenditure for the 2006-2016 period- are we converging?
2019
The depth and persistence of the Great Recession that started in 2008 had a considerable impact on income distribution and inequality. Therefore, studies of living standards and evolution of income inequality are trend topics nowadays. Our goal was to estimate the impact of the economic crises on household expenditure and the trends and evolution of regional inequality. We applied our analysis to the Spanish case based on Household Budget Survey data from Instituto Nacional de Estadística (INE, the National Statistics Institute) and the period of eleven years between 2006 and 2016. A model that showed good results in modelling income was the biparametric gamma model, which is further very u…