نتایج جستجو برای: linear trends especially with small samples
تعداد نتایج: 9790253 فیلتر نتایج به سال:
background: small photon fields are increasingly used in modern radiotherapy especially in intensity modulated radiation therapy (imrt) and stereotactic radiosurgery (srs) treatments. accurate beam profile and central axis depth doses measurements of such beams are complicated due to the electron disequilibrium. hence the ebt2 (external beam therapy) gafchromic film was used for dosimetry of sm...
High repetition rate (HRR) lasers are essential in multiphoton microscopy for satisfactory signal to noise at low average powers. However, HRR lasers generate thermal distortions in samples even with the slightest single photon absorption. Using an optical chopper with HRR lasers ("blanking") we demonstrate a femtosecond z-scan setup that effectively eliminates thermal as well as small linear a...
Background and Purpose: Birth outcomes and fertility measures are commonly evaluated in Maternal and Child Health Integrated Program (MCHIP) in the field of public health. Given the key role of time- trend study in the projection of current data to the future, this population-based study aimed to describe the significant changes of birth outcomes and fertility measures in the rural population...
Feature selection can significantly be decisive when analyzing high dimensional data, especially with a small number of samples. Feature extraction methods do not have decent performance in these conditions. With small sample sets and high dimensional data, exploring a large search space and learning from insufficient samples becomes extremely hard. As a result, neural networks and clustering a...
estimating fetal weight in utero, for better management of pregnancy and appropriate timing of delivery especially in high-risk pregnancies is necessary. our purpose to evaluate a simple method in estimating fetal weight in iranian pregnant patients and also to compare was with a previous western study. this study was carried out in arash hospital, tehran university of medical sciences in 1996-...
saluk mount is selected for devonian biostratigraphy. this area located at southwest of bojnurd. in this study three sections are selected and two sections, chahar-borj and tabar sections with a thickness of 650 m, which consist mainly of calcareous sediments was studied in detailed but third section, qelli section, with a thickness of about 450m which consist mainly of sandstone and evaporates...
Propensity scores are increasingly being used in large sample studies to control for pregroup differences. Because these scores are often used to match cases, they can result in sample attrition. In smaller sample studies, such attrition leaves too few cases for meaningful analysis. Alternatives when working with small samples are to use propensity scores as covariates to control for pre-group ...
in this investigation the effect of external field on the electron density of nanostructures of cds, cdse, cdte, gaas and polymeric structure of three, four, five and six units of cds as a kind of nanosolar cells has been studied theoretically. as modeling this system in nanodimension, molecular structures has used. specific properties of molecular structures permit us to consider different sym...
this study examines development of social competence, and behavior problems in kindergarten children during a specific period of childhood.a sample of 499 kindergarten children (244 girls and 255 boys) with the age range of 2 years up to 5 years and 6 months was selected using the random stratified sampling method. to collect data, california preschool social competence scale and social skills ...
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