نتایج جستجو برای: c31
تعداد نتایج: 361 فیلتر نتایج به سال:
A nonparametric procedure for quantile regression, or more generally nonparametric M-estimation, is proposed which is completely data-driven and adapts locally to the regularity of the regression function. This is achieved by considering in each point M-estimators over different local neighbourhoods and by a local model selection procedure based on sequential testing. Non-asymptotic risk bounds...
Amostras de ceras do ninho e da própolis de Apis mellifera foram analisadas. Observou-se a predominância de ésteres, seguidos de hidrocarbonetos. Os constituintes foram identificados por cromatografia a gás/espectrometria de massas. Amplas variações foram observadas nos padrões de hidrocarbonetos e dos ácidos e álcoois de ésteres. As cadeias carbônicas dos hidrocarbonetos abrangem a faixa C23 C...
Does Increasing Parents’ Schooling Raise the Schooling of the Next Generation? Evidence Based on Conditional Second Moments This paper investigates the degree of intergenerational transmission of education for individuals from the National Longitudinal Survey of Youth 1979. Rather than identifying the causal effect of parental education via instrumental variables we exploit the feature of the t...
Complex patterns of steroidal biomarkers in Tertiary lacustrine sediments of the Biyang Basin, China
Gas chromatography (GC), gas chromatography±mass spectrometry (GC±MS) and gas chromatography±mass spectrometry±mass spectrometry (GC±MS±MS) with co-injected synthetic standards were used to analyse the biomarker patterns of some Tertiary lacustrine clayey dolomites from the Biyang Basin, China. The lithology, low Pr/Ph ratio and high gammacerane content of these sediments indicated that high sa...
Streptomyces roseosporus mutants that express enhanced recombination between partially homologous (homeologous) sequences were isolated by selection for recombination between the bacteriophage phi C31 derivative KC570 containing the Streptomyces coelicolor glucose kinase (glk) gene and the S. roseosporus chromosome. The frequencies of homeologous recombination in the ehr mutants were determined...
We invent Implicit Marshallian Demands, a new type of demand function that combines desirable features of Hicksian and Marshallian demand functions. We propose and estimate the Exact Af ne Stone Index (EASI) Implicit Marshallian Demand system. Like the Almost Ideal Demand (AID) system, EASI budget shares are linear in parameters given real expenditures. However, unlike the AID, EASI demands can...
This work has been funded by Palarq Foundation, Spanish Ministry of Culture and Sport (42-T002018042853 170-T002019038589), Direction Cultural Heritage (Ministry Communication, Morocco), Faculty Sciences (Mohamed 1r University Oujda, INSAP (Institut National des de l’Archeologie et du Patrimoine), Agencia Estatal Investigacion (Spanish Science, Innovation Universities: CGL2016-76431-P, CGL2016-...
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