Search results for "statistical"
showing 10 items of 4960 documents
Hamiltonian tools for the analysis of optical polarization control
2011
Import JabRef; International audience; The study of the polarization dynamics of two counterpropagating beams in optical fibers has recently been the subject of a growing renewed interest, from both the theoretical and experimental points of view. This system exhibits a phenomenon of polarization attraction, which can be used to achieve a complete polarization of an initially unpolarized signal beam, almost without any loss of energy. Along the same way, an arbitrary polarization state of the signal beam can be controlled and converted into any other desired state of polarization, by adjusting the polarization state of the counterpropagating pump beam. These properties have been demonstrate…
New Author Guidelines for Displaying Data and Reporting Data Analysis and Statistical Methods in Experimental Biology
2019
The American Society for Pharmacology and Experimental Therapeutics has revised the Instructions to Authors for Drug Metabolism and Disposition, Journal of Pharmacology and Experimental Therapeutics, and Molecular Pharmacology These revisions relate to data analysis (including statistical analysis) and reporting but do not tell investigators how to design and perform their experiments. Their overall focus is on greater granularity in the description of what has been done and found. Key recommendations include the need to differentiate between preplanned, hypothesis-testing, and exploratory experiments or studies; explanations of whether key elements of study design, such as sample size and …
Maternal body mass index, gestational weight gain, and the risk of overweight and obesity across childhood: An individual participant data meta-analy…
2019
Background Maternal obesity and excessive gestational weight gain may have persistent effects on offspring fat development. However, it remains unclear whether these effects differ by severity of obesity, and whether these effects are restricted to the extremes of maternal body mass index (BMI) and gestational weight gain. We aimed to assess the separate and combined associations of maternal BMI and gestational weight gain with the risk of overweight/obesity throughout childhood, and their population impact. Methods and findings We conducted an individual participant data meta-analysis of data from 162,129 mothers and their children from 37 pregnancy and birth cohort studies from Europe, No…
Controlling false match rates in record linkage using extreme value theory
2011
AbstractCleansing data from synonyms and homonyms is a relevant task in fields where high quality of data is crucial, for example in disease registries and medical research networks. Record linkage provides methods for minimizing synonym and homonym errors thereby improving data quality. We focus our attention to the case of homonym errors (in the following denoted as ‘false matches’), in which records belonging to different entities are wrongly classified as equal. Synonym errors (‘false non-matches’) occur when a single entity maps to multiple records in the linkage result. They are not considered in this study because in our application domain they are not as crucial as false matches. Fa…
Descriptive Statistics
2009
A set of medical data is based on a collection of the data of individual cases or objects, also called observation units or statistical units. Every case, for example every study participant, patient, every experimental animal, every tooth or every cell shows comparable parameters (such as body weight, gender, erosion, pH). Each of these parameters, also called variables, has a specific parameter value (gender = male, age = 30 years, weight = 70 kg) for each observation unit (for example the patient). The aim of descriptive statistics is to summarize the data, so that they can be clearly illustrated (1–3). The property of a parameter is specified by its so-called scale of measure. Generally…
MDA: a MATLAB-based program for morphospace-disparity analysis
2003
A MATLAB® program that examines patterns of state-space occupation is described. Four subroutines are available with which to visualize morphospace patterns: (i) in terms of their features such as dispersion, aggregation and location, thereby allowing users to extract complementary quantitative information about how the state-space is structured, and (ii) in terms of changes in those patterns that can be compared with other biotic (e.g., extinction, origination rates) or abiotic (e.g., environmental proxy) information. The program incorporates many of the latest and most widely used statistical parameters for describing multivariate spaces. The parameters are estimated on the basis of boots…
Tripotential data processing for HES interpretation
1994
In this paper some methods are proposed and compared to correct the experimental measurements for preliminary processing of tripotential data which are acquired for HES prospecting. However, the use of those methods should be based upon an accurate analysis of all experimental data. Such an analysis ought to involve: 1) an estimate of the averaged measurement errors with their variance and distribution in both the space and the three apparent-resistivities domains; 2) the choice of a resistivity model capable of describing the actual volume under study. The differences among the three values of apparent resistivity measured on a point are generally influenced both by the resistivity distrib…
Environmental Data Processing by Clustering Methods for Energy Forecast and Planning
2011
This paper presents a statistical approach based on the k-means clustering technique to manage environmental sampled data to evaluate and to forecast of the energy deliverable by different renewable sources in a given site. In particular, wind speed and solar irradiance sampled data are studied in association to the energy capability of a wind generator and a photovoltaic (PV) plant, respectively. The proposed method allows the sub-sets of useful data, describing the energy capability of a site, to be extracted from a set of experimental observations belonging the considered site. The data collection is performed in Sicily, in the south of Italy, as case study. As far as the wind generation…
A Comparison between Heuristic, Statistical and Data-driven Methods in Landslide Susceptibility Assessment: an Application to the Briga and Giampilie…
2014
Susceptibility assessment concerning the estimation of areas prone to landslide is one of the most useful approach in the analysis of landslide hazard. Over the last years, in an attempt to find the best approach to evaluate landslide susceptibility, many methods have been developed. Among these, the heuristic, the statistical, and the data-driven approaches are very widespread, and they all are based on the concept that the conditions which led to landslide movements in the past will control the probability of movement occurrence in the future. This study presents an assessment of landslide susceptibility in which models of the three different methodologies, such as the heuristic approach,…
The short-term efficacy and safety of artificial total disc replacement for selected patients with lumbar degenerative disc disease compared with ant…
2018
PurposeTo systematically compare the efficacy and safety of lumbar total disc replacement (TDR) with the efficacy and safety of anterior lumbar interbody fusion (ALIF) for the treatment of lumbar degenerative disc disease (LDDD).MethodsThe electronic databases PubMed, Web of Science and the Cochrane Library were searched for the period from the establishment of the databases to March 2018. The peer-reviewed articles that investigate the safety and efficacy of TDR and ALIF were retrieved under the given search terms. Quality assessment must be done independently by two authors according to each item of criterion. The statistical analyses were performed using RevMan (version 5.3) and Stata (v…