159 research outputs found

    Non-Market Valuation of Open Space and Other Amenities Associated with Retention of Lands in Agricultural Use

    Get PDF
    The most productive farmland in southcentral Alaska is currently under intense development pressure due to rapid population increases and consequential increases in demand for suburban housing. This study utilizes a contingent valuation iterative bidding game to estimate the willingness of Matanuska-Susitna Borough residents to pay to preserve open space and other historical/environmental amenities associated with farming activities. Determinants of consumer behavior are addressed as well as total benefits and costs of various posited development scenarios. This information may be useful to policymakers assessing actions designed to purchase development rights from Matanuska-Susitna farmers

    Reprimo G>C and P53R2 C>G 4696 single nucleotide polymorphisms and colorectal cancer: A case-control disease-association study.

    Get PDF
    This thesis presents a case-control disease association research project examining association between single nucleotide polymorphisms (SNPs) of the P53R2 and Reprimo genes and colorectal cancer (CRC). Identifying the genetic risk factors may help to reduce the incidence of CRC by allowing identification of individuals at increased CRC risk through genetic screening. Individuals identified as having increased CRC risk could then have tailored management aiming to reduce their risk and detect CRC at an early, potentially curable stage. P53R2 and Reprimo are both involved in cell cycle control and DNA repair. P53R2 supplies deoxyribonucleotides for repair of damaged DNA and Reprimo is involved in cell cycle arrest in response to genotoxic stress, allowing DNA repair to take place or for apoptosis. Both genes are induced by the tumour suppressor gene TP53. Dysfunction of P53R2 or Reprimo may lead to errors in DNA repair or cell cycle arrest, mechanisms that are recognised in carcinogenesis. SNPs are known to be able to alter gene function and it is thought that SNPs may account for some of the molecular pathology involved in common complex diseases such as cancer. Two SNPs were studied, P53R2 C>G 4696 and Reprimo G>C 842, using a case control method. Cases with histologically proven CRC were compared with two control populations; young, healthy individuals and individuals with diverticular disease (DD). DNA was obtained from buccal cell biopsies and the populations genotyped using an allele specific polymerase chain reaction (PCR) or polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) methods. Tests for Hardy-Weinberg equilibrium (HWE) and allelic- and genotype-disease association were performed using an on line SNP-disease association calculator. An association between the Reprimo G>C 842 C allele and CRC was detected on heterozygous and allele positivity testing when using the young, healthy population as a control. However, this association is likely to be a false positive result confounding factors and was not replicated when using the matched DD population. The DD population was found to deviate from HWE with respect to Reprimo G>C 824 and therefore a disease association may exist. Otherwise no associations between the study SNPs and CRC were detected

    Differential transcriptomic responses to heat stress in surface and subterranean diving beetles

    Get PDF
    Subterranean habitats are generally very stable environments, and as such evolutionary transitions of organisms from surface to subterranean lifestyles may cause considerable shifts in physiology, particularly with respect to thermal tolerance. In this study we compared responses to heat shock at the molecular level in a geographically widespread, surface-dwelling water beetle to a congeneric subterranean species restricted to a single aquifer (Dytiscidae: Hydroporinae). The obligate subterranean beetle Paroster macrosturtensis is known to have a lower thermal tolerance compared to surface lineages (CTmax 38°C cf. 42–46°C), but the genetic basis of this physiological difference has not been characterized. We experimentally manipulated the thermal environment of 24 individuals to demonstrate that both species can mount a heat shock response at high temperatures (35°C), as determined by comparative transcriptomics. However, genes involved in these responses differ between species and a far greater number were differentially expressed in the surface taxon, suggesting it can mount a more robust heat shock response; these data may underpin its higher thermal tolerance compared to subterranean relatives. In contrast, the subterranean species examined not only differentially expressed fewer genes in response to increasing temperatures, but also in the presence of the experimental setup employed here alone. Our results suggest P. macrosturtensis may be comparatively poorly equipped to respond to both thermally induced stress and environmental disturbances more broadly. The molecular findings presented here have conservation implications for P. macrosturtensis and contribute to a growing narrative concerning weakened thermal tolerances in obligate subterranean organisms at the molecular level

    Carbonic anhydrase IX promotes tumor growth and necrosis in vivo and inhibition enhances anti-VEGF therapy.

    Get PDF
    PURPOSE: Bevacizumab, an anti-VEGFA antibody, inhibits the developing vasculature of tumors, but resistance is common. Antiangiogenic therapy induces hypoxia and we observed increased expression of hypoxia-regulated genes, including carbonic anhydrase IX (CAIX), in response to bevacizumab treatment in xenografts. CAIX expression correlates with poor prognosis in most tumor types and with worse outcome in bevacizumab-treated patients with metastatic colorectal cancer, malignant astrocytoma, and recurrent malignant glioma. EXPERIMENTAL DESIGN: We knocked down CAIX expression by short hairpin RNA in a colon cancer (HT29) and a glioblastoma (U87) cell line which have high hypoxic induction of CAIX and overexpressed CAIX in HCT116 cells which has low CAIX. We investigated the effect on growth rate in three-dimensional (3D) culture and in vivo, and examined the effect of CAIX knockdown in combination with bevacizumab. RESULTS: CAIX expression was associated with increased growth rate in spheroids and in vivo. Surprisingly, CAIX expression was associated with increased necrosis and apoptosis in vivo and in vitro. We found that acidity inhibits CAIX activity over the pH range found in tumors (pK = 6.84), and this may be the mechanism whereby excess acid self-limits the build-up of extracellular acid. Expression of another hypoxia inducible CA isoform, CAXII, was upregulated in 3D but not two-dimensional culture in response to CAIX knockdown. CAIX knockdown enhanced the effect of bevacizumab treatment, reducing tumor growth rate in vivo. CONCLUSION: This work provides evidence that inhibition of the hypoxic adaptation to antiangiogenic therapy enhances bevacizumab treatment and highlights the value of developing small molecules or antibodies which inhibit CAIX for combination therapy

    Operationalizing the centiloid scale for [18F]florbetapir PET studies on PET/MRI

    Get PDF
    INTRODUCTION: The Centiloid scale aims to harmonize amyloid beta (Aβ) positron emission tomography (PET) measures across different analysis methods. As Centiloids were created using PET/computerized tomography (CT) data and are influenced by scanner differences, we investigated the Centiloid transformation with data from Insight 46 acquired with PET/magnetic resonanceimaging (MRI). METHODS: We transformed standardized uptake value ratios (SUVRs) from 432 florbetapir PET/MRI scans processed using whole cerebellum (WC) and white matter (WM) references, with and without partial volume correction. Gaussian-mixture-modelling-derived cutpoints for Aβ PET positivity were converted. RESULTS: The Centiloid cutpoint was 14.2 for WC SUVRs. The relationship between WM and WC uptake differed between the calibration and testing datasets, producing implausibly low WM-based Centiloids. Linear adjustment produced a WM-based cutpoint of 18.1. DISCUSSION: Transformation of PET/MRI florbetapir data to Centiloids is valid. However, further understanding of the effects of acquisition or biological factors on the transformation using a WM reference is needed

    Taking It to the Extreme:The Effect of Coalition Cabinets on Foreign Policy

    Get PDF
    Institutional constraints have been offered by some scholars as an explanation for why multiparty coalitions should be more peaceful than single-party cabinets. Yet others see the same institutional setting as a prescription for more aggressive behavior. Recent research has investigated these conflicting expectations, but with mixed results. We examine the theoretical bases for these alternative expectations about the effects of coalition politics on foreign policy. We find that previous research is limited theoretically by confounding institutional effects with policy positions, and empirically by analyzing only international conflict data. We address these limitations by examining cases of foreign policy behavior using the World Event/Interaction Survey (WEIS) dataset. Consistent with our observation that institutional constraints have been confounded with policy positions, we find that coalitions are neither more aggressive nor more peaceful, but do engage in more extreme foreign policy behaviors. These findings are discussed with regard to various perspectives on the role of institutions in shaping foreign policy behavior.</p

    The Herpes Simplex Virus-1 Transactivator Infected Cell Protein-4 Drives VEGF-A Dependent Neovascularization

    Get PDF
    Herpes simplex virus-1 (HSV-1) causes lifelong infection affecting between 50 and 90% of the global population. In addition to causing dermal lesions, HSV-1 is a leading cause of blindness resulting from recurrent corneal infection. Corneal disease is characterized by loss of corneal immunologic privilege and extensive neovascularization driven by vascular endothelial growth factor-A (VEGF-A). In the current study, we identify HSV-1 infected cells as the dominant source of VEGF-A during acute infection, and VEGF-A transcription did not require TLR signaling or MAP kinase activation. Rather than being an innate response to the pathogen, VEGF-A transcription was directly activated by the HSV-1 encoded immediate early transcription factor, ICP4. ICP4 bound the proximal human VEGF-A promoter and was sufficient to promote transcription. Transcriptional activation also required cis GC-box elements common to the VEGF-A promoter and HSV-1 early genes. Our results suggest that the neovascularization characteristic of ocular HSV-1 disease is a direct result of HSV-1's major transcriptional regulator, ICP4, and similarities between the VEGF-A promoter and those of HSV-1 early genes

    Integrating data types to estimate spatial patterns of avian migration across the Western Hemisphere

    Get PDF
    For many avian species, spatial migration patterns remain largely undescribed, especially across hemispheric extents. Recent advancements in tracking technologies and high-resolution species distribution models (i.e., eBird Status and Trends products) provide new insights into migratory bird movements and offer a promising opportunity for integrating independent data sources to describe avian migration. Here, we present a three-stage modeling framework for estimating spatial patterns of avian migration. First, we integrate tracking and band re-encounter data to quantify migratory connectivity, defined as the relative proportions of individuals migrating between breeding and nonbreeding regions. Next, we use estimated connectivity proportions along with eBird occurrence probabilities to produce probabilistic least-cost path (LCP) indices. In a final step, we use generalized additive mixed models (GAMMs) both to evaluate the ability of LCP indices to accurately predict (i.e., as a covariate) observed locations derived from tracking and band re-encounter data sets versus pseudo-absence locations during migratory periods and to create a fully integrated (i.e., eBird occurrence, LCP, and tracking/band re-encounter data) spatial prediction index for mapping species-specific seasonal migrations. To illustrate this approach, we apply this framework to describe seasonal migrations of 12 bird species across the Western Hemisphere during pre- and postbreeding migratory periods (i.e., spring and fall, respectively). We found that including LCP indices with eBird occurrence in GAMMs generally improved the ability to accurately predict observed migratory locations compared to models with eBird occurrence alone. Using three performance metrics, the eBird + LCP model demonstrated equivalent or superior fit relative to the eBird-only model for 22 of 24 species–season GAMMs. In particular, the integrated index filled in spatial gaps for species with over-water movements and those that migrated over land where there were few eBird sightings and, thus, low predictive ability of eBird occurrence probabilities (e.g., Amazonian rainforest in South America). This methodology of combining individual-based seasonal movement data with temporally dynamic species distribution models provides a comprehensive approach to integrating multiple data types to describe broad-scale spatial patterns of animal movement. Further development and customization of this approach will continue to advance knowledge about the full annual cycle and conservation of migratory birds
    • …
    corecore