Louisiana State University

About: Louisiana State University is a education organization based out in Baton Rouge, Louisiana, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 40206 authors who have published 76587 publications receiving 2566076 citations. The organization is also known as: LSU & Louisiana State University and Agricultural and Mechanical College.

Neutral and adaptive variation in gene expression.

Abstract: Variation among populations in gene expression should be related to the accumulation of random-neutral changes and evolution by natural selection. The following evolutionary analysis has general applicability to biological and medical science because it accounts for genetic relatedness and identifies patterns of expression variation that are affected by natural selection. To identify genes evolving by natural selection, we allocate the maximum among-population variation to genetic distance and then examine the remaining variation relative to a hypothesized important ecological parameter (temperature). These analyses measure the expression of metabolic genes in common-gardened populations of the fish Fundulus heteroclitus whose habitat is distributed along a steep thermal gradient. Although much of the variation in gene expression fits a null model of neutral drift, the variation in expression for 22% of the genes that regress with habitat temperature was far greater than could be accounted for by genetic distance alone. The most parsimonious explanation for among-population variation for these genes is evolution by natural selection. In addition, many metabolic genes have patterns of variation incongruent with neutral evolution: They have too much or too little variation. These patterns of biological variation in expression may reflect important physiological or ecological functions.

The role of attention in the treatment of attention-maintained self-injurious behavior: noncontingent reinforcement and differential reinforcement of other behavior.

Abstract: Because there are potentially serious limitations to differential reinforcement of other behavior (DRO) (which is probably the most widely used treatment procedure for behavior problems), we examined an alternative procedure--noncontingent reinforcement (NCR). Three females with developmental disabilities, all of whom engaged in severe self-injurious behavior, participated. During a pretreatment functional analysis, each subject's self-injury was shown to be differentially sensitive to social attention as a maintaining consequence. Next, each subject was exposed to a DRO treatment and an NCR treatment. During DRO, attention was delivered contingent on the absence of self-injury for prespecified intervals. During NCR, attention was delivered on a fixed-time schedule that was not influenced by the subject's behavior. Results showed that both procedures were highly effective in reducing self-injury, probably because the functional reinforcer for self-injury was used during treatment. Furthermore, there was evidence that NCR attenuated several of the limitations of DRO. These results are particularly interesting in light of the long experimental history of NCR as a control rather than as a therapeutic procedure.

A formalin-inactivated whole SIV vaccine confers protection in macaques

Abstract: A vaccine against human immunodeficiency virus (HIV) would be highly effective in stopping the acquired immunodeficiency syndrome (AIDS) epidemic. A comprehensive evaluation of potential vaccine methodologies can be made by means of the simian model for AIDS, which takes advantage of the similarities in viral composition and disease potential between simian immunodeficiency virus (SIV) infection of rhesus macaques and HIV infection in humans. Immunization with a formalin-inactivated whole SIV vaccine potentiated with either alum and the Syntex adjuvant threonyl muramyl dipeptide (MDP) or MDP alone resulted in the protection of eight of nine rhesus monkeys challenged with ten animal-infectious doses of pathogenic virus. These results demonstrate that a whole virus vaccine is highly effective in inducing immune responses that can protect against lentivirus infection and AIDS-like disease.

Relationships among net primary productivity, nutrients and climate in tropical rain forest: a pan‐tropical analysis

Abstract: Tropical rain forests play a dominant role in global biosphere-atmosphere CO2 exchange. Although climate and nutrient availability regulate net primary production (NPP) and decomposition in all terrestrial ecosystems, the nature and extent of such controls in tropical forests remain poorly resolved. We conducted a meta-analysis of carbon-nutrient-climate relationships in 113 sites across the tropical forest biome. Our analyses showed that mean annual temperature was the strongest predictor of aboveground NPP (ANPP) across all tropical forests, but this relationship was driven by distinct temperature differences between upland and lowland forests. Within lowland forests (< 1000 m), a regression tree analysis revealed that foliar and soil-based measurements of phosphorus (P) were the only variables that explained a significant proportion of the variation in ANPP, although the relationships were weak. However, foliar P, foliar nitrogen (N), litter decomposition rate (k), soil N and soil respiration were all directly related with total surface (0‐10 cm) soil P concentrations. Our analysis provides some evidence that P availability regulates NPP and other ecosystem processes in lowland tropical forests, but more importantly, underscores the need for a series of large-scale nutrient manipulations ‐ especially in lowland forests ‐ to elucidate the most important nutrient interactions and controls.