1,931 research outputs found

    Life without the Beach: Projected Sea Level Rise and its Impact on Barrier Islands Along the East Coast, USA

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    As climate change is becoming a global issue, the impact of sea level rise is increasingly becoming a threat to humans, wildlife, infrastructure, and ecosystems. To evaluate the effects of sea level rise on barrier islands and coastal regions, we studied future projections of sea level rise at Ocean City and Assateague Island, Maryland. We hypothesize that the sea levels at Assateague and Ocean City will have different beach profiles, and will show different levels of flooding through the Representative Concentration Pathways (RCP) simulations. We measured beach profiles at four locations, two at Ocean City and two at Assateague Island, to view the current beach profiles and found that Ocean City reveals a smaller average change in elevation compared to Assateague. We also used a LiDAR Digital Elevation Model (DEM) of Ocean City and Assateague Island to run RCP 2.6, RCP 4.5, and RCP 8.5 simulations using GIS to represent the Intergovernmental Panel on Climate Change (IPCC) projected sea level rise for the year 2100. We found that Ocean City has higher predicted percentages of flooded land but smaller areas of flooded land compared to Assateague. These results indicate that significant areas of both Ocean City and Assateague Island will be flooded by 2100 regardless of which RCP simulation might be true. However, it is projected that the RCP 2.6 simulation is an underestimation of potential flooding and the future will more closely resemble the RCP 8.5 simulation if drastic precautions are not taken now. This will severely impact ecosystems, economies, and human life

    Cranial and trunk neural crest cells use different mechanisms for attachment to extracellular matrices

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    We have used a quantitative cell attachment assay to compare the interactions of cranial and trunk neural crest cells with the extracellular matrix (ECM) molecules fibronectin, laminin and collagen types I and IV. Antibodies to the β_1 subunit of integrin inhibited attachment under all conditions tested, suggesting that integrins mediate neural crest cell interactions with these ECM molecules. The HNK-1 antibody against a surface carbohydrate epitope under certain conditions inhibited both cranial and trunk neural crest cell attachment to laminin, but not to fibronectin. An antiserum to α_1 intergrin inhibited attachment of trunk, but not cranial, neural crest cells to laminin and collagen type I, though interactions with fibronectin or collagen type IV were unaffected. The surface properties of trunk and cranial neural crest cells differed in several ways. First, trunk neural crest cells attached to collagen types I and IV, but cranial neural crest cells did not. Second, their divalent cation requirements for attachment to ECM molecules differed. For fibronectin substrata, trunk neural crest cells required divalent cations for attachment, whereas cranial neural crest cells bound in the absence of divalent cations. However, cranial neural crest cells lost this cation-independent attachment after a few days of culture. For laminin substrata, trunk cells used two integrins, one divalent cation-dependent and the other divalent cation-independent (Lallier, T. E. and Bronner-Fraser, M. (1991) Development 113, 1069–1081). In contrast, cranial neural crest cells attached to laminin using a single, divalent cation-dependent receptor system. Immunoprecipitations and immunoblots of surface labelled neural crest cells with HNK-1, α_1 integrin and β_1 integrin antibodies suggest that cranial and trunk neural crest cells possess biochemically distinct integrins. Our results demonstrate that cranial and trunk cells differ in their mechanisms of adhesion to selected ECM components, suggesting that they are non-overlapping populations of cells with regard to their adhesive properties

    Strain differences in susceptibility to cisplatin-induced renal fibrosis

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    Cisplatin is a potent chemotherapeutic; the dose-limiting side effect of this drug is nephrotoxicity, causing acute kidney injury (AKI) in 30% of adult patients. Patients with cisplatin-induced AKI are more likely to develop end stage renal diseases, particularly chronic kidney disease (CKD), which is marked by the development of fibrosis. Currently, there are no therapeutic interventions for cisplatin-induced kidney injury, which may be due to limitations in the mouse model used to study this type of injury. We have previously developed a repeated dosing regimen of cisplatin (mice treated with 7 mg/kg once a week for 4 weeks, mice sacrificed at Day 24). With this dosing regimen, FVB/n background mice survive and develop renal fibrosis indicative of CKD. Commonly, C57BL/6J background mice are utilized to study the nephrotoxic effects of cisplatin on the kidney; however, C57BL/6J mice have been shown to be resistant to renal fibrosis in some models of experimental fibrosis. We wanted to determine if the resistance to the development of renal fibrosis would also be evident with our repeated dosing regimen of cisplatin. Preliminary data have indicated that while FVB/n mice develop fibrosis when treated with 7 mg/kg of cisplatin, C57BL/6J mice do not. We hypothesized that C57BL/6J mice will require a higher dose of cisplatin in order to develop interstitial fibrosis that occurs with repeated dosing of cisplatin. Several techniques were utilized including QRTPCR, IHC, and Western blot analysis to determine the presence of fibrosis in these mice, as well as compare fibrotic and inflammatory markers to FVB/n mice treated with cisplatin. Both strains of mice treated with repeated dosing of cisplatin had a robust inflammatory response and an increase in fibrotic marker levels. These data suggest that C57BL/6J mice are susceptible to the development of renal fibrosis with our repeated dosing model of cisplatin

    Bayesian calibration of the nitrous oxide emission module of an agro-ecosystem model

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    Nitrous oxide (N2O) is the main biogenic greenhouse gas contributing to the global warming potential (GWP) of agro-ecosystems. Evaluating the impact of agriculture on climate therefore requires a capacity to predict N2O emissions in relation to environmental conditions and crop management. Biophysical models simulating the dynamics of carbon and nitrogen in agro-ecosystems have a unique potential to explore these relationships, but are fraught with high uncertainties in their parameters due to their variations over time and space. Here, we used a Bayesian approach to calibrate the parameters of the N2O submodel of the agro-ecosystem model CERES-EGC. The submodel simulates N2O emissions from the nitrification and denitrification processes, which are modelled as the product of a potential rate with three dimensionless factors related to soil water content, nitrogen content and temperature. These equations involve a total set of 15 parameters, four of which are site-specific and should be measured on site, while the other 11 are considered global, i.e. invariant over time and space. We first gathered prior information on the model parameters based on the literature review, and assigned them uniform probability distributions. A Bayesian method based on the Metropolis–Hastings algorithm was subsequently developed to update the parameter distributions against a database of seven different field-sites in France. Three parallel Markov chains were run to ensure a convergence of the algorithm. This site-specific calibration significantly reduced the spread in parameter distribution, and the uncertainty in the N2O simulations. The model’s root mean square error (RMSE) was also abated by 73% across the field sites compared to the prior parameterization. The Bayesian calibration was subsequently applied simultaneously to all data sets, to obtain better global estimates for the parameters initially deemed universal. This made it possible to reduce the RMSE by 33% on average, compared to the uncalibrated model. These global parameter values may be used to obtain more realistic estimates of N2O emissions from arable soils at regional or continental scales

    Evidence for olfactory learning in procellariiform seabird chicks

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    Burrow nesting procellariiform seabirds use olfactory cues for both foraging and nest recognition. As chicks, burrow nesters develop in the dark, but are exposed to both prey-related and individual-specific scents through contact with their parents. This exposure suggests that chicks may have the opportunity to learn odors while still in the nest. In this study, we examined whether exposure to odorants during development might influence olfactory search behavior expressed later in life. To test this idea, we exposed eggs of thin-billed prions Pachyptila belcheri to a rosy-scented novel odor (phenyl ethyl alcohol, PEA) or a control (water) just before hatching; chicks were then tested with these odors in a simple wind tunnel. Prior to fledgling, subjects who had received pre-exposure to PEA displayed head sweeps nearly twice as frequently as control birds did when presented with PEA. This study demonstrates that under natural rearing conditions, procellariiforms learn odor characteristics of their rearing environment in the nest

    Quantum error correction benchmarks for continuous weak parity measurements

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    We present an experimental procedure to determine the usefulness of a measurement scheme for quantum error correction (QEC). A QEC scheme typically requires the ability to prepare entangled states, to carry out multi-qubit measurements, and to perform certain recovery operations conditioned on measurement outcomes. As a consequence, the experimental benchmark of a QEC scheme is a tall order because it requires the conjuncture of many elementary components. Our scheme opens the path to experimental benchmarks of individual components of QEC. Our numerical simulations show that certain parity measurements realized in circuit quantum electrodynamics are on the verge of being useful for QEC

    PRODUCT RECALL STRATEGIES: UNITED STATES VS. CHINA

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    poster abstractA product recall is defined as an action by a manufacturer or distributor to remove a product from the market because it may possibly cause health problems or death (Zhao & Hu, 2011). Product recalls occur because of in-adequate inspection techniques, employees who are unfamiliar with the pro-cess, improper product design, etc. Companies can make decisions concern-ing their proactiveness/reactiveness (procedure) and compensation (out-come) toward the affected consumers when dealing with product harm cri-ses. Will there be national cultural differences in consumer responses to the-se decisions and in the proposed moderating effect of the degree of product hazard? Based on the above analysis, a quantitative analysis using ques-tionnaires was performed. The methodology was a controlled experiment, manipulating 2 levels of compensation (high vs. low), 2 recall strategies (proactive vs. reactive) and 2 levels of product hazard (high vs. low). A group of 200 undergraduate business students in the U.S. and Hong Kong were given surveys that assessed their purchase intention and other factors, based on the manipulated variables. Using t-test and one-way ANOVA anal-yses in SPSS 16.0, the results show that, when companies are proactive in their recall strategy, consumers care less about the outcome, no matter how severe the product hazard is, while, when companies use a passive recall strategy, consumers care more about the outcome. Although companies are not able to avoid recalls completely, it is important that they develop an ef-fective method to increase consumer repurchases and recover quickly when dealing with a product harm crisis. The results also demonstrate that both procedure and outcome have significant effect on consumers’ attitudinal and behavioral reactions. Further data is being collected to see if there is a sig-nificant difference between respondents in mainland China versus the U.S
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