A detailed geochemical study and a sequence stratigraphic interpretation have been conducted on a sedimentary sequence of the Upper Cretaceous La Luna Formation, in a section outcropping in the eastern ̄ank of the Middle Magdalena Basin (MMB), Colombia. The goals were to evaluate geochemical variability related to lithofacies and organic facies changes, characterize depositional environment and...

Various methods are used to prevent the deterioration of biotechnological properties brewer’s yeast during storage. This paper studied use artificial neural networks for mathematical modeling correcting biosynthetic activity seed C34 race storage with natural minerals. The input parameters were suspending medium (water, beer wort, or young beer); type zeolite-containing tuff from Siberian depos...

Se evaluaron los biomarcadores en la fracción de hidrocarburos saturados (n-alcanos, pristano, fitano, terpanos y esteranos) un ensayo biorremediación 90 días con crudo extrapesado (10 ºAPI). Con base presencia una muestra compleja no resuelta (MCNR), deficiencia n-alcanos, fitano hopanos desmetilados (25-norhopanos), se determinó que el original está biodegradado. La detección pristano (más se...

This paper presents some two-step estimators for a wide range of parametric panel data models with censored endogenous variables and sample selection bias. Our approach is to derive estimates of the unobserved heterogeneity responsible for the endogeneity/selection bias to include as additional explanatory variables in the primary equation. These are obtained through a decomposition of the redu...

Mortality rates computed from data reported in the British Household Panel Survey are lower than those computed from registration of deaths; the main source of this error is likely to be a failure to distinguish non-response due to unreported death from other forms of non-response. Here we model the interaction between state of health, mortality and non-response of men aged 65 and over in a tri...

Does Immigration Policy Affect the Education-Occupation Mismatch? Evidence from Australia This paper analyses the impact of a change in Australia’s immigration policy, introduced on 1 July 1999, on migrants’ probability of being over-/under-educated or correctly matched. The policy change consists of stricter entry requirements about age, language ability, education, and work experience. The re...