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.

The inherent instability of mutant p53 is alleviated by Mdm2 or p16INK4a loss

Abstract: The p53 tumor suppressor is often disrupted in human cancers by the acquisition of missense mutations. We generated mice with a missense mutation at codon 172 that mimics the p53R175H hot spot mutation in human cancer. p53 homozygous mutant mice have unstable mutant p53 in normal cells and stabilize mutant p53 in some but not all tumors. To investigate the significance of these data, we examined the regulation of mutant p53 stability by Mdm2, an E3 ubiquitin ligase that targets p53 for degradation, and p16INK4a, a member of the Rb tumor suppressor pathway. Mice lacking Mdm2 or p16INK4a stabilized mutant p53, and revealed an earlier age of tumor onset than p53 mutant mice and a gain-of-function metastatic phenotype. Analysis of tumors from p53 homozygous mutant mice with stable p53 revealed defects in the Rb pathway. Additionally, ionizing radiation stabilizes wild-type and mutant p53. Thus, the stabilization of mutant p53 is not a given but it is a prerequisite for its gain-of-function phenotype. Since mutant p53 stability mimics that of wild-type p53, these data indicate that drugs aimed at activating wild-type p53 will also stabilize mutant p53 with dire consequences.

Sedimentation, accretion, and subsidence in marshes of Barataria Basin, Louisiana1

Abstract: Vertical accretion and sediment accumulation rates were determined from the distribution of 137Cs in cores collected from freshwater, intermediate, brackish, and salt marshes in the Barataria Basin, Louisiana. Vertical accretion rates vary from about 1.3 cm*yr-l in levee areas to 0.7 in backmarshes. Mineral sediment content of the marsh soil profile decreased with distance from the coast. However, vertical accretion rates were about equivalent in areas of the same type. Autochthonous organic matter appears to be an important factor defining the process and rate of vertical accretion, especially in the freshwater marshes. Except in natural levee areas, marsh accretion rates are less than subsidence measured by water level data, however this alone cannot account for observed land-loss patterns in the basin area.

Contemporary Trends and Issues in it Adoption and Diffusion Research

Abstract: The high level of investigative activity to date into information systems and information technology acceptance and diffusion has witnessed the use of a wide range of exploratory techniques, examining many different systems and technologies in countless different contexts and geographical locations. The aim of this paper is to provide a comprehensive and systematic review of the literature pertaining to such adoption and diffusion issues in order to observe trends, ascertain the current ‘state of play’, and to highlight promising lines of inquiry including those lacking investigative activity or simply being in need of renewed interest. Previous research activity was analysed along a number dimensions including units of analysis, research paradigms, methodologies, and methods, theories and theoretical constructs, and technologies/contexts examined. Information on these and other variables was extracted during an examination of 345 papers on innovation adoption, acceptance and diffusion appearing in 19 peer-reviewed journals between 1985 and 2007. Findings suggest that the positivist paradigm, empirical and quantitative research, the survey method and Technology Acceptance Model theory (and its associated constructs) were predominantly used in the body of work examined, revealing clear opportunities for researchers to make original contributions by making greater use of the theoretical and methodological variety available to them, and consequently reducing the risk of research in the area moving toward overall homogeneity.

Properties and Astrophysical Implications of the 150 M Binary Black Hole Merger GW190521

Abstract: The gravitational-wave signal GW190521 is consistent with a binary black hole (BBH) merger source at redshift 0.8 with unusually high component masses, 85-14+21 M o˙ and 66-18+17 M o˙, compared to previously reported events, and shows mild evidence for spin-induced orbital precession. The primary falls in the mass gap predicted by (pulsational) pair-instability supernova theory, in the approximate range 65-120 M o˙. The probability that at least one of the black holes in GW190521 is in that range is 99.0%. The final mass of the merger (142-16+28 M o˙) classifies it as an intermediate-mass black hole. Under the assumption of a quasi-circular BBH coalescence, we detail the physical properties of GW190521's source binary and its post-merger remnant, including component masses and spin vectors. Three different waveform models, as well as direct comparison to numerical solutions of general relativity, yield consistent estimates of these properties. Tests of strong-field general relativity targeting the merger-ringdown stages of the coalescence indicate consistency of the observed signal with theoretical predictions. We estimate the merger rate of similar systems to be 0.13-0.11+0.30 Gpc-3 yr-1. We discuss the astrophysical implications of GW190521 for stellar collapse and for the possible formation of black holes in the pair-instability mass gap through various channels: via (multiple) stellar coalescences, or via hierarchical mergers of lower-mass black holes in star clusters or in active galactic nuclei. We find it to be unlikely that GW190521 is a strongly lensed signal of a lower-mass black hole binary merger. We also discuss more exotic possible sources for GW190521, including a highly eccentric black hole binary, or a primordial black hole binary.