Compact chromatin structure, induction of gene silencing in position-effect variegation (PEV), and crossing-over suppression are typical features of heterochromatin. To identify genes affecting crossing-over suppression by heterochromatin we tested PEV suppressor mutations for their effects on crossing over in pericentromeric regions of Drosophila autosomes. From the 46 mutations (28 loci) stud...

A variety of methods is available to estimate a portfolio’s Value-at-Risk. Aside from the overall VaR there is an apparent need for information about marginal VaR, component VaR and incremental VaR. Expressions for these VaR metrics have been derived under the restrictive normality assumption. In this paper we investigate these VaR concepts in an elliptical world and in a general distribution-f...

Antigenic variation in the human malaria parasite Plasmodium falciparum depends on the transcriptional regulation of the var gene family. In each individual parasite, mRNA is expressed exclusively from 1 var gene out of ∼60, while the rest of the genes are transcriptionally silenced. Both modifications to chromatin structure and DNA regulatory elements associated with each var gene have been im...

Cyclopoid copepods and mosquito larvae were surveyed in southwestern Louisiana rice fields. Almost every rice field had a natural population of Mesocyclops ruttneri, Acanthocylops vernalis, or Macrocyclops albidus. Judging from the abundance of pupae, 29% of the fields were responsible for virtually all Anopheles quadrimaculatus production, apparently because larval mortality suppressed product...

After publication of the article [1], it has been brought to our attention that the original version of this Article contained a typo in the 3rd paragraph of the section 'Review process and data extraction'. It concerns the equation published as "Var(lnRR) = Var(lnR1 + lnR0)". On the right part, the "+" within the parenthesis should be "-", as defined and derived from the left part. As a result...

BACKGROUND The reservoir of Plasmodium infection in humans has traditionally been defined by blood slide positivity. This study was designed to characterize the local reservoir of infection in relation to the diverse var genes that encode the major surface antigen of Plasmodium falciparum blood stages and underlie the parasite's ability to establish chronic infection and transmit from human to ...

A four-dimensional ensemble variational (4D-EnVar) data assimilation has been developed for a limited area model. The integration of tangent linear and adjoint models, as applied in standard 4D-Var, is replaced with the use of an ensemble of non-linear model states to estimate fourdimensional background error covariances over the assimilation time window. The computational costs for 4D-En-Var a...