195 research outputs found
An application of a small area procedure with correlation between measurement error and sampling error to the Conservation Effects Assessment Project
County level estimates of mean sheet and rill erosion from the Conservation
Effects Assessment Project (CEAP) are useful for program development and
evaluation. Since county sample sizes in the CEAP survey are insufficient to
support reliable direct estimators, small area estimation procedures are
needed. The quantity of water runoff is a useful covariate but is unavailable
for the full population. We use an estimate of mean runoff from the CEAP survey
as a covariate in a small area model with sheet and rill erosion as the
response. As the runoff and sheet and rill erosion are estimators from the same
survey, the measurement error in the covariate is important as is the
correlation between the measurement error and the sampling error. We conduct a
detailed investigation of small area estimation in the presence of a
correlation between the measurement error in the covariate and the sampling
error in the response. In simulations, the proposed predictor is superior to
small area predictors that assume the response and covariate are uncorrelated
or that ignore the measurement error entirely
Estudio etnobotánico de áreas del noroeste de la provincia de Isfahan, Iran
Iran is one of the countries which enormously used medicinal plants from the ancient times. In this study, we documented the ethnobotanical data of Golpayegan, and Shahin Shahr and Meymeh counties (Isfahan province) for the first time in Iran. Field study and plant collecting were done in different seasons in 2016–2017. Ethnobotanical data were analyzed using information of questionnaires gained from 27 inhabitants. Totally, 48 plants of 24 families were recorded from studied areas. Asteraceae (36%) and Lamiaceae (23%) are those containing the biggest numbers of cited plants. Moreover, leaves (45.83%) and seeds (18.75%) were the most used parts. This study indicated the importance of useful plants of studied areas and the necessity of doing this kind of research on other parts of country in order to preserve this valuable information of local inhabitants.Irán es un paÃs que ha utilizado de manera destacada las plantas medicinales desde la antigüedad. En este estudio, documentamos los datos etnobotánicos de los condados de Golpayegan, Shahin Shahr y Meymeh (provincia de Isfahán) por primera vez en Irán. El estudio de campo y la recolección de plantas se realizaron en diferentes temporadas en 2016 y 2017. Los datos etnobotánicos se analizaron utilizando información proveniente de cuestionarios realizados a 27 informantes. En total, se registraron 48 plantas de 24 familias de las áreas estudiadas. Las familias Asteraceae (36%) y Lamiaceae (23%) son las que contienen un mayor número de plantas citadas. Las hojas (45,83%) y las semillas (18,75%) son las partes de planta más utilizadas. Este estudio indica la importancia de las plantas útiles de las áreas estudiadas y la necesidad de realizar este tipo de investigación en otras partes del paÃs con el fin de preservar esta valiosa información de los habitantes locales
Epidermal micromorphology of floret parts in Aeluropus (Poaceae)
Aeluropus from Poaceae comprises 5 species in the world and 3 species in Iran. This halophytic perennial is distributed in salty and dry soils of Asia, Europe, and Africa. In addition to being used as fodder, it can stabilize the soil by its rhizome or stolon. These features make Aeluropus a valuable plant. In this study, lemma and palea of 10 populations of Aeluropus were studied micromorphologically by scanning electron microscope (SEM) to determine diagnostic features among species studied. Eight characters as micro-prickle, macro-hair, long cell outline, cork and silica cells, papilla, salt gland, and epicuticular wax were studied. The occurrence of salt glands and silica cells in populations/taxa studied showed the ability of Aeluropus to tolerate harsh habitats. Our result showed the taxonomic value of floret micromorphological features to separate Aeluropus species
An Unbiased Predictor for Skewed Response Variable with Measurement Error in Covariate
We introduce a new small area predictor when the Fay-Herriot normal error
model is fitted to a logarithmically transformed response variable, and the
covariate is measured with error. This framework has been previously studied by
Mosaferi et al. (2023). The empirical predictor given in their manuscript
cannot perform uniformly better than the direct estimator. Our proposed
predictor in this manuscript is unbiased and can perform uniformly better than
the one proposed in Mosaferi et al. (2023). We derive an approximation of the
mean squared error (MSE) for the predictor. The prediction intervals based on
the MSE suffer from coverage problems. Thus, we propose a non-parametric
bootstrap prediction interval which is more accurate. This problem is of great
interest in small area applications since statistical agencies and agricultural
surveys are often asked to produce estimates of right skewed variables with
covariates measured with errors. With Monte Carlo simulation studies and two
Census Bureau's data sets, we demonstrate the superiority of our proposed
methodology
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