Indiana University

About: Indiana University is a education organization based out in Bloomington, Indiana, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 64480 authors who have published 150058 publications receiving 6392902 citations. The organization is also known as: Indiana University system & indiana.edu.

Prevalence of low femoral bone density in older U.S. adults from NHANES III.

Abstract: Data on the number of U.S. women with low femoral bone mineral density (BMD) are currently available only from indirect estimates. We used dual-energy X-ray absorptiometry (DXA) measurements of femoral BMD from phase 1 of the third National Health and Nutrition Examination Survey (NHANES III, 1988-1991) to estimate prevalences of low femoral BMD in women ages 50 years and older using an approach proposed recently by an expert panel of the World Health Organization (WHO). Cutpoints for low BMD were derived from BMD data of 194 non-Hispanic white (NHW) women aged 20-29 years from the NHANES III dataset. The prevalence of older U.S. women with femoral osteopenia (BMD between 1 standard deviation [SD] and 2.5 SD below the mean of young NHW women) ranged from 34-50% in four different femur regions, which corresponds to approximately 12-17 million women. The prevalence with osteoporosis (BMD > 2.5 SD below the mean of young NHW women) ranged from 17-20%, or approximately 6-7 million women. Prevalences were 1.3-2.4 times higher in NHW women than non-Hispanic black women (NHB), and 0.8-1.2 times higher in NHW versus Mexican American (MA) women. The estimated numbers of NHW, NHB, and MA women with osteopenia were 10-15 million, 800,000-1.2 million, and 300,000-400,000, respectively; corresponding figures for osteoporosis were 5-6 million, 200,000-300,000, and 100,000 respectively. Thus, the first data on BMD from a nationally representative sample of older women show a substantial number with low femoral BMD.(ABSTRACT TRUNCATED AT 250 WORDS)

International Corporate Governance and Corporate Cash Holdings

Abstract: Agency problems are an important determinant of corporate cash holdings. For a sample of more than 11,000 firms from 45 countries, we find that corporations in countries where shareholders rights are not well protected hold up to twice as much cash as corporations in countries with good shareholder protection. In addition, when shareholder protection is poor, factors that generally drive the need for cash holdings, such as investment opportunities and asymmetric information, actually become less important. These results are stronger after controlling for capital market development. Indeed, consistent with the importance of agency costs, we find that firms hold larger cash balances when access to funds is easier. Our evidence is consistent with the conjecture that investors in countries with poor shareholder protection cannot force managers to disgorge excessive cash balances.

Regional Forest Fragmentation and the Nesting Success of Migratory Birds

Abstract: Forest fragmentation, the disruption in the continuity of forest habitat, is hypothesized to be a major cause of population decline for some species of forest birds because fragmentation reduces nesting (reproductive) success Nest predation and parasitism by cowbirds increased with forest fragmentation in nine midwestern (United States) landscapes that varied from 6 to 95 percent forest cover within a 10-kilometer radius of the study areas Observed reproductive rates were low enough for some species in the most fragmented landscapes to suggest that their populations are sinks that depend for perpetuation on immigration from reproductive source populations in landscapes with more extensive forest cover Conservation strategies should consider preservation and restoration of large, unfragmented "core" areas in each region

The rock–paper–scissors game and the evolution of alternative male strategies

Abstract: MANY species exhibit colour polymorphisms associated with alternative male reproductive strategies, including territorial males and 'sneaker males' that behave and look like females1–3. The prevalence of multiple morphs is a challenge to evolutionary theory because a single strategy should prevail unless morphs have exactly equal fitness4,5 or a fitness advantage when rare6,7. We report here the application of an evolutionary stable strategy model to a three-morph mating system in the side-blotched lizard. Using parameter estimates from field data, the model predicted oscillations in morph frequency, and the frequencies of the three male morphs were found to oscillate over a six-year period in the field. The fitnesses of each morph relative to other morphs were non-transitive in that each morph could invade another morph when rare, but was itself invadable by another morph when common. Concordance between frequency-dependent selection and the among-year changes in morph fitnesses suggest that male interactions drive a dynamic 'rock–paper–scissors' game7.

Mechanism of auxin perception by the TIR1 ubiquitin ligase

Abstract: Auxin is a pivotal plant hormone that controls many aspects of plant growth and development. Perceived by a small family of F-box proteins including transport inhibitor response 1 (TIR1), auxin regulates gene expression by promoting SCF ubiquitin-ligase-catalysed degradation of the Aux/IAA transcription repressors, but how the TIR1 F-box protein senses and becomes activated by auxin remains unclear. Here we present the crystal structures of the Arabidopsis TIR1-ASK1 complex, free and in complexes with three different auxin compounds and an Aux/IAA substrate peptide. These structures show that the leucine-rich repeat domain of TIR1 contains an unexpected inositol hexakisphosphate co-factor and recognizes auxin and the Aux/IAA polypeptide substrate through a single surface pocket. Anchored to the base of the TIR1 pocket, auxin binds to a partially promiscuous site, which can also accommodate various auxin analogues. Docked on top of auxin, the Aux/IAA substrate peptide occupies the rest of the TIR1 pocket and completely encloses the hormone-binding site. By filling in a hydrophobic cavity at the protein interface, auxin enhances the TIR1-substrate interactions by acting as a 'molecular glue'. Our results establish the first structural model of a plant hormone receptor.