Search results for "sampling"

Permutation Test (PT) and Tolerated Difference Test (TDT): Two new, robust and powerful nonparametric tests for statistical comparison of dissolution…

2013

The most popular way of comparing oral solid forms of drug formulations from different batches or manufacturers is through dissolution profile comparison. Usually, a similarity factor known as (f2) is employed; However, the level of confidence associated with this method is uncertain and its statistical power is low. In addition, f2 lacks the flexibility needed to perform in special scenarios. In this study two new statistical tests based on nonparametrical Permutation Test theory are described, the Permutation Test (PT), which is very restrictive to confer similarity, and the Tolerated Difference Test (TDT), which has flexible restrictedness to confer similarity, are described and compared…

Multivariate-Analysis of Phytoplankton and Related Environmental-Factors, in a Shallow Hypertrophic Lake

1995

Data on some relevant environmental variables and phytoplankton species composition, collected from the hypertrophic shallow lake Albufera of Valencia (Spain) during 1980-88, were examined using Redundancy Analysis (RDA). The hydrological cycle of the lake is manipulated for rice cultivation in the area. Seasonality and the particular hydrological cycle of the lake were the principal factors influencing long-term phytoplankton dynamics. Annual or horizontal differences were less important than the seasonal factor. However, a trend of phosphate increase and underwater illumination decrease was observed between 1980 and 1988. These changes might be related to some species year-to-year variati…

Assessment of the statistical significance of classifications in infrared spectroscopy based diagnostic models.

2014

Fourier transform infrared (IR) spectroscopy in combination with multivariate data analysis is a versatile tool that can be applied to disease diagnosis. However, a rigorous validation of the obtained models is necessary in order to obtain robust results. This work evaluates the advantages of the use of permutation testing for determining the statistical significance of the misclassification errors obtained from IR based diagnostic models through cross validation (CV). The model performance, estimated by CV, is compared to a distribution of CV-performance values obtained using randomly permuted class labels. The distribution of ‘random CV-values’ is considered as a null distribution and use…

Stochastic Nonlinear Time Series Forecasting Using Time-Delay Reservoir Computers: Performance and Universality

2014

International audience; Reservoir computing is a recently introduced machine learning paradigm that has already shown excellent performances in the processing of empirical data. We study a particular kind of reservoir computers called time-delay reservoirs that are constructed out of the sampling of the solution of a time-delay diFFerential equation and show their good performance in the forecasting of the conditional covariances associated to multivariate discrete-time nonlinear stochastic processes of VEC-GARCH type as well as in the prediction of factual daily market realized volatilities computed with intraday quotes, using as training input daily log-return series of moderate size. We …

Determination of vinegar acidity by attenuated total reflectance infrared measurements through the use of second-order absorbance-pH matrices and par…

2007

Univariate (zero-order), multivariate (first-order) and multiway (second-order) calibrations were assayed for the determination of vinegar acidity using a mechanized procedure based upon vibrational spectroscopy and the emerging multicommutation methodology. The second-order methodology relies on the use of a flow system based on multicommutation and binary sampling. The flow network comprises a set of three-way solenoid valves, computer-controlled to provide facilities to handle the sample and to generate a time-dependent pH gradient using two carrier solutions. The procedure is based on the volumetric fraction variation approach that maintains the same volume of sample solution and dynami…

Health literacy of pregnant women and duration of breastfeeding maintenance: a feasibility study

2020

Research the association between health literacy (HL) and exclusive breastfeeding at 4-months postpartum.Despite the benefits of breastfeeding (BF), its rates are low worldwide. Among the reasons for abandonment is the level of maternal education. Maternal education has been associated with HL, but evidence between HL and BF maintenance is limited.A cross-sectional study.The sample compromised 229 nursing mothers recruited from January 2018 to the end of December 2018 at Spain by systematic sampling method. Women were interviewed postpartum on parameters associated with the start and continuation of BF up to 4 months postpartum. Multivariate logistic regression models to explain exposure va…

Discordance between two national health statistics sources (EMH and EESCRI, 1990–2009). Analysis of psychiatric morbidity

2013

Abstract Introduction Two statistical sources provide data on hospital stays and discharges for all Spanish hospitals: Hospital Morbidity Survey (acronym in Spanish: EMH) and Statistics of Health Establishments providing Inpatient Care (acronym in Spanish: EESCRI). Our aim is to contrast these two statistical sources to define their accuracy and relevance in psychiatric epidemiology studies. Material and methodology The analysis is based on two aspects: (1) Compare the number of psychiatric stays and hospital discharges from 1990 to 2009. (2) Analyse and compare how the average stay is provided. Results The differences between the two statistical sources are significant and increase over ti…

Some experimental issues of AFM tip blind estimation. The effect of noise and resolution

2006

The convolution of tip shape on sample topography can introduce significant inaccuracy in an AFM image, when the tip radius is comparable to the typical dimension of the sample features to be observed. The blind estimation method allows one to obtain information on the AFM tip through an unknown characterizer sample and thus to perform the deconvolution of the tip shape from an image. When applying the blind estimation method to determine the AFM tip shape, some apparently trivial issues relating to the experimental operating parameters must be taken into account. In this paper, the effects of the operating parameters, e.g., sampling intervals (resolution) and instrumental noise, have been …

CAPI Versus PAPI and The Production of Non-Sampling Errors

2009

P26 Early motherhood: a qualitative study exploring experiences of adolescent mothers in the hohoe municipality of ghana

2018

Background Each year between 14 and 15 million adolescent girls give birth, accounting for more than 10% of births globally. Motherhood is an exciting time for every woman and the society at large and also seen as a significant part of any woman’s identity but that is often not the case for the adolescent mother. Adolescent motherhood can be a time of mixed feelings as it occurs at a critical time of their lives. This study examined challenges adolescent mothers face during early motherhood and strategies to improve early motherhood for better social and health outcomes. Methods Based on a phenomenological perspective, this qualitative study was conducted in the Hohoe Municipality where pur…