1,648 research outputs found

    Designing Policies to Open Trade

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    In this paper we consider recent proposals to auction U.S. import quotas. using the funds so obtained to encourage relocation out of the protected industries. We argue that the information available to the government, or lack thereof, is a critical factor in understanding these policies. In a world or full information, it makes little sense to use auction quotas rather than tariffs. Similarly, it is unclear why an elaborate program of temporary protection is needed, rather than immediately opening trade and compensating people with an income transfer. When the government has Limited information, however, these policies become quite sensible and may even be optimal.

    Impacts of Climate Change on Frequency of Floods and Droughts in Idaho

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    Analyses of changes in the flood frequency relationships over the last century will be presented for key river reaches in Idaho. In addition, projections of the impacts of increasing temperatures on the ability of Idaho\u27s water resources to meet demands will be presented for key water use areas within the state

    Deciphering the factors that influence participation in studies requiring serial lumbar punctures

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    Introduction: Cerebrospinal fluid biomarkers increasingly inform the causes of dementia and may provide objective markers of disease progression. There is a need to decipher participant and procedural factors that promote participation in studies incorporating longitudinal biomarker measures. Methods: Participant and procedural factors associated with participation in longitudinal biomarker studies were determined in individuals enrolled in studies of memory and aging at the Knight Alzheimer Disease Research Center (Saint Louis, MO, USA). Results: Complications were encountered following 331 of 1484 lumbar punctures (22.3%; LPs), affecting 280 of 929 participants (30.1%); in \u3e95% complications were minor. Three hundred fifteen of 679 eligible participants (46.4%) completed multiple LPs. Younger age (odds ratio [OR] 2.08 per decade [95% confidence interval (CI) 1.61-2.94]), normal cognition (OR 21.4 [2.85-160.1]), and the absence of heart disease (OR 2.0 [1.01-3.85]) or seizures at study entry identified participants with increased odds of completing three or more LPs. Discussion: Factors influencing participation may be leveraged to improve recruitment and retention within observational and therapeutic studies requiring serial LPs

    GeV-Scale Thermal WIMPs: Not Even Slightly Dead

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    Weakly Interacting Massive Particles (WIMPs) have long reigned as one of the leading classes of dark matter candidates. The observed dark matter abundance can be naturally obtained by freezeout of weak-scale dark matter annihilations in the early universe. This "thermal WIMP" scenario makes direct predictions for the total annihilation cross section that can be tested in present-day experiments. While the dark matter mass constraint can be as high as mχ≳100m_\chi\gtrsim100 GeV for particular annihilation channels, the constraint on the total cross section has not been determined. We construct the first model-independent limit on the WIMP total annihilation cross section, showing that allowed combinations of the annihilation-channel branching ratios considerably weaken the sensitivity. For thermal WIMPs with s-wave 2→22\rightarrow2 annihilation to visible final states, we find the dark matter mass is only known to be mχ≳20m_\chi\gtrsim20 GeV. This is the strongest largely model-independent lower limit on the mass of thermal-relic WIMPs, together with the upper limit on the mass from the unitarity bound (mχ≲100m_\chi\lesssim 100 TeV), it defines what we call the "WIMP window". To probe the remaining mass range, we outline ways forward.Comment: 16 pages, 10 figures, references added, accepted for publication in PR

    Use of Roadside Deer Removal to Reduce Deer–Vehicle Collisions

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    Identification of management tools to reduce the incidence of deer–vehicle collisions (DVCs) is important to improve motorist safety. Sharpshooting to reduce white-tailed deer (Odocoileus virginianus; deer) along roads has proven successful in urban situations but has not been evaluated in undeveloped areas. We used a before-after-control-impact (BACI) design to evaluate the use of sharpshooting to reduce DVCs along roads on the uninhabited U.S. Department of Energy’s Savannah River Site, South Carolina, USA, during 2011–2017. We removed 242 deer from 4 treatment roads during 2015 and 2016, with 2-year removal rates per road averaging 5.0 deer/km of road (range 4.0–5.8). We monitored accident rates as DVCs per million vehicle-km traveled (VKT) during annual cycles (March–February) following the initial removal and during the 7 months (March–September) following removals in spring and the 5 months (October–February) following removals in fall. The response in accident rates varied among the annual cycle, spring, and fall. The BACI effect indicated that removal treatments reduced accident rate by 1.184 DVCs per million VKT (P = 0.081) over the annual cycle and by 1.528 DVCs per million VKT (P = 0.023) following spring removals, but following fall removals we detected no effect (P = 0.541). Relative to the pre-removal accident rate for removal roads, the estimated treatment effect on an annual basis equated to a 39.4% reduction in accidents and during spring equated to a 50.8% reduction in accidents. We conclude that sharpshooting along roads in undeveloped areas can be a viable tool to reduce DVCs and can be useful in areas where population control via hunter harvest is not practical or desirable

    Model of Tooth Morphogenesis Predicts Carabelli Cusp Expression, Size, and Symmetry in Humans

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    The patterning cascade model of tooth morphogenesis accounts for shape development through the interaction of a small number of genes. In the model, gene expression both directs development and is controlled by the shape of developing teeth. Enamel knots (zones of nonproliferating epithelium) mark the future sites of cusps. In order to form, a new enamel knot must escape the inhibitory fields surrounding other enamel knots before crown components become spatially fixed as morphogenesis ceases. Because cusp location on a fully formed tooth reflects enamel knot placement and tooth size is limited by the cessation of morphogenesis, the model predicts that cusp expression varies with intercusp spacing relative to tooth size. Although previous studies in humans have supported the model's implications, here we directly test the model's predictions for the expression, size, and symmetry of Carabelli cusp, a variation present in many human populations.In a dental cast sample of upper first molars (M1s) (187 rights, 189 lefts, and 185 antimeric pairs), we measured tooth area and intercusp distances with a Hirox digital microscope. We assessed Carabelli expression quantitatively as an area in a subsample and qualitatively using two typological schemes in the full sample. As predicted, low relative intercusp distance is associated with Carabelli expression in both right and left samples using either qualitative or quantitative measures. Furthermore, asymmetry in Carabelli area is associated with asymmetry in relative intercusp spacing.These findings support the model's predictions for Carabelli cusp expression both across and within individuals. By comparing right-left pairs of the same individual, our data show that small variations in developmental timing or spacing of enamel knots can influence cusp pattern independently of genotype. Our findings suggest that during evolution new cusps may first appear as a result of small changes in the spacing of enamel knots relative to crown size

    Birc2/Iap1 regulates endothelial cell integrity and blood vessel homeostasis.

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    none4noneM. SANTORO; TEMESGEN SAMUEL; TRACY MITCHEL; JOHN C. REED AND DIDIER Y. STAINIERSantoro, Massimo; Temesgen, Samuel; Tracy, Mitchel; JOHN C. REED AND DIDIER Y., Stainie

    Production of biochemicals and biofuels with no CO2 production and improved product yields

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    Traditional fermentation processes for the production of the majority of biochemicals and biofuels produce CO2 because of decarboxylation reactions, which limits the final mass yields of products. To overcome this limitation, we have developed a fermentation technology called MixoFerm™ (also known as anaerobic, non-photosynthetic mixotrophy), which uses microorganisms capable of simultaneously consuming both organic (e.g., sugars) and inorganic (e.g., CO2, CO, or H2) substrates. With this technology, product mass yields for almost any biochemical or biofuel can be increased by at least 50%, and processes can be designed that result in no CO2 production. In order to achieve zero CO2 emissions for most products, exogenous reductant must be added to the system, since sugar lacks the necessary reducing energy to both fix CO2 and produce the product of interest. Here, we demonstrate concurrent consumption of both sugars and exogenously added reducing gases (CO and/or H2) to produce products of interest at enhanced mass yields and with no CO2 emissions. In addition, we have screened a library of acetogenic bacteria in order to find an optimal MixoFerm™ host strain, one that consumes both a broad range of carbohydrates and gases. From this library, we identified strains with a broader carbohydrate consumption range than traditional acetogens like C. ljungdahlii or C. autoethanogenum, and characterized their ability to grow under a variety of MixoFerm™ conditions to produce biochemicals at enhanced mass yields. With the ability to improve product yields for reduced products, especially for ethanol and other potential biofuels, MixoFerm™ is a robust and flexible platform technology to improve process economics and product life-cycle analysis

    Axin2 as regulatory and therapeutic target in newborn brain injury and remyelination.

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    Permanent damage to white matter tracts, comprising axons and myelinating oligodendrocytes, is an important component of brain injuries of the newborn that cause cerebral palsy and cognitive disabilities, as well as multiple sclerosis in adults. However, regulatory factors relevant in human developmental myelin disorders and in myelin regeneration are unclear. We found that AXIN2 was expressed in immature oligodendrocyte progenitor cells (OLPs) in white matter lesions of human newborns with neonatal hypoxic-ischemic and gliotic brain damage, as well as in active multiple sclerosis lesions in adults. Axin2 is a target of Wnt transcriptional activation that negatively feeds back on the pathway, promoting β-catenin degradation. We found that Axin2 function was essential for normal kinetics of remyelination. The small molecule inhibitor XAV939, which targets the enzymatic activity of tankyrase, acted to stabilize Axin2 levels in OLPs from brain and spinal cord and accelerated their differentiation and myelination after hypoxic and demyelinating injury. Together, these findings indicate that Axin2 is an essential regulator of remyelination and that it might serve as a pharmacological checkpoint in this process
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