459 research outputs found

    Nuisance to nemesis: nuclear fallout and intelligence as secrets, problems, and limitations on the arms race, 1940-1964

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    Fallout sampling and other nuclear intelligence techniques were the most important sources of United States strategic intelligence in the early Cold War. Operated as the Atomic Energy Detection System by a covert Air Force unit known as AFOAT-1, the AEDS detected emissions and analyzed fallout from Soviet nuclear tests, as well as provided quantitative intelligence on the size of the Russian nuclear stockpile. Virtually unknown because the only greater Cold War secret than nuclear weapons was intelligence gathered about them, data on the Soviet threat produced by AFOAT-1 was an extraordinary influence on early National Intelligence Estimates, the rapid growth of the Strategic Air Command, and strategic war plans. Official guidance beginning with the first nuclear test in 1945 otherwise suggested fallout was an insignificant effect of nuclear weapons. Following AFOAT-1's detection of Soviet testing in fall 1949 and against the cautions raised about the problematic nature of higher yield weapons by the General Advisory Committee, the Atomic Energy Commission’s top scientific advisers, President Harry Truman ordered the AEC to quickly build these extraordinarily powerful weapons, testing the first in secrecy in November 1952. In spring 1954, the second test of an American thermonuclear (or hydrogen) bomb, CASTLE BRAVO, produced more than 7,000 square miles of potentially lethal fallout deposition near its ground zero, as well as contaminating people and fish in a notorious fallout radiation exposure incident. These tests also produced residual fallout that intensified every spring as it returned from the stratosphere. In April 1954, J. Robert Oppenheimer, formerly scientific director of the Manhattan Project and chair of the AEC's GAC, was permanently stripped of his clearance to handle classified information, ostensibly for failing to display sufficient enthusiasm during development of this weapon. This hearing was effectively a sham that served as a proxy for Air Force efforts to silence his concerns and those of a secret AEC study named GABRIEL, warnings that in the event of war the problematic nature of the cumulative fallout from these weapons would afflict the populations of both the victim and the aggressor as they contaminated the global environment. The transnational public outcry in the years that followed the CASTLE BRAVO fallout incident put intense pressure on political leaders to end testing. The deciding factor at the White House proved to be several instances of fallout contamination of the food supply involving wheat and milk. Tellingly, this was due to the limited fallout from testing alone. This data provided an empirical basis to underwrite earlier cautions that general nuclear war would yield no winner, only varying degrees of loss. Utilizing the high-altitude capabilities of the U-2, the data that proved the need for caution was provided to researchers by the Air Force. No longer as useful a secret, the military, too, came to see fallout as an issue that unnecessarily problematized their reliance on nuclear weapons. To blunt efforts to achieve a comprehensive test ban, the Air Force pursued underground testing to forestall continuing fallout that would raise deeper questions about the viability of nuclear war itself. Rather than a mere propaganda problem, as it was often seen by officials, fallout proved to be a practical limitation on the use of nuclear weapons. The 1963 Limited Test Ban Treaty that resulted ended most atmospheric testing, but not the possibility that fallout could some day contaminate the planet

    Survival and Reproduction of Wild Turkeys in the Northern Black Hills of South Dakota

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    In South Dakota, wild turkeys are a high-interest species for both consumptive and non-consumptive uses.  Harvest records indicate that the population segment residing in the northern Black Hills may be declining.  Although data on hen survival, nesting survival, and early poult survival were collected for the southern Black Hills in the early 2000s, there is currently a paucity of demographic data for the northern Black Hills.  We seek to inform wild turkey management by characterizing demography specifically for the northern Black Hills.  We radio-tracked 80 turkey hens (40 adults/40 juveniles) in 2016 to estimate rates of hen survival, nesting, nesting success, and early poult survival; this two-year study will continue in 2017.  Based on preliminary data, rates of nesting by adult hens are lower in the northern Black Hills than the southern Black Hills (77.5% vs. 98%), as are rates of renesting by adult hens (33% vs. 75%).  We are in the process of estimating hen survival, but preliminary results indicate that annual survival is approximately 50%.  Poult survival to 4 weeks is comparable in the northern and southern Black Hills, but lower than in other portions of the range of Merriam’s wild turkey.  Although the northern and southern Black Hills are in close proximity, the substantial climatic differences likely explain the reduced productivity of the turkey population in the northern Black Hills.  Limiting fall harvest of wild turkey hens in the northern Black Hills may be required to sustainably manage this important game species

    The Oak Ridge Polycystic Kidney mouse: Modeling ciliopathies of mice and men

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    The Oak Ridge Polycystic Kidney (ORPK) mouse was described nearly 14 years ago as a model for human recessive polycystic kidney disease. The ORPK mouse arose through integration of a transgene into an intron of the Ift88 gene resulting in a hypomorphic allele (Ift88(Tg737Rpw)). The Ift88(Tg737Rp omega) mutation impairs intraflagellar transport (IFT), a process required for assembly of motile and immotile cilia. Historically, the primary immotile cilium was thought to have minimal importance for human health; however, a rapidly expanding number of human disorders have now been attributed to ciliary defects. Importantly, many of these phenotypes are present and can be analyzed using the ORPK mouse. In this review, we highlight the research conducted using the OPRK mouse and the phenotypes shared with human cilia disorders. Furthermore, we describe an additional follicular dysplasia phenotype in the ORPK mouse, which alongside the ectodermal dysplasias seen in human Ellis-van Creveld and Sensenbrenner's syndromes, suggests an unappreciated role for primary cilia in the skin and hair follicle

    Land management effects on wet aggregate stability and carbon content

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    Land management affects soil structure and many other soil properties and processes. Our objectives were to evaluate soil organic C (SOC), aggregate size distribution, aggregate-associated C, and soil structure as affected by long-term land management and slope. A chronosequence of 38 on-farm sites with low to high (5–18%) slopes was selected to evaluate 5–40 yr of management. The sites were classified as business as usual (BAU) cropland (BAU-Crop), BAU pasture (BAU-Past), newly established conservation reserve program (CRP) areas (CRP-New), and established CRP (CRP-Old). Soil samples were collected from the 0-to-5- and 5-to-15-cm depth increments and processed for soil property measurements including fractionation by wet sieving into five aggregate size classes (\u3e2,000, 1,000–2,000, 500–1,000, 250–500, and 53–250 μm). Within the surface 5 cm, mean weight diameter (MWD) and geometric mean diameter (GMD) were used to characterize soil structural stability. The BAU-Past and CRP-Old sites had 79% more macroaggregates (\u3e2,000, 1,000–2,000, and 500–1,000 μm), 123% higher MWD, 38% higher GMD, and 47% higher SOC than BAU-Crop or CRP-New sites. The 5-to-15-cm depth increment showed a similar but lower magnitude response. Aggregate-associated C was quantified using a constant soil mass that reflected aggregate size distribution to prevent overestimating C content. Lower-slope locations had more SOC, more macroaggregates, more C associated with macroaggregates, and higher GMD and MWD compared with high-slope locations across all management classifications and soil depths. The results support our hypothesis that the high-slop soils may benefits from specific management decisions than the lower-sloping soils as a function of landscape property. We recommend reestablishing grassland on sloping land that is susceptible to excessive soil erosion, although those practices will likely take a long time to restore soil structural stability and SOC content to precultivation levels

    Avalanches on a conical bead pile: scaling with tuning parameters

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    Uniform spherical beads were used to explore the behavior of a granular system near its critical angle of repose on a conical bead pile. We found two tuning parameters that could take the system to a critical point where a simple power-law described the avalanche size distribution as predicted by self-organized criticality, which proposed that complex dynamical systems self-organize to a critical point without need for tuning. Our distributions were well described by a simple power-law with the power {\tau} = 1.5 when dropping beads slowly onto the apex of a bead pile from a small height. However, we could also move the system from the critical point using either of two tuning parameters: the height from which the beads fell onto the top of the pile or the region over which the beads struck the pile. As the drop height increased, the system did not reach the critical point yet the resulting distributions were independent of the bead mass, coefficient of friction, or coefficient of restitution. All our apex-dropping distributions for any type of bead (glass, stainless steel, zirconium) showed universality by scaling onto a common curve with {\tau} = 1.5 and {\sigma} = 1.0, where 1/{\sigma} is the power of the tuning parameter. From independent calculations using the moments of the distribution, we find values for {\tau} = 1.6 \pm 0.1 and {\sigma} = 0.91 \pm 0.15. When beads were dropped across the surface of the pile instead of solely on the apex, then the system also moved from the critical point and again the avalanche size distributions fell on a common curve when scaled similarly using the same values of {\tau} and {\sigma}. We also observed that an hcp structure on the base of the pile caused an emergent structure in the pile that had six faces with some fcc or hcp structure.Comment: 8 pages, 6 figures; submitted to Granular Matter; Reformatted into LaTeX from Word; Fixed typo in uncertainty of tau; Rearranged two paragraphs to improve flo

    Increasing confidence and changing behaviors in primary care providers engaged in genetic counselling.

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    BackgroundScreening and counseling for genetic conditions is an increasingly important part of primary care practice, particularly given the paucity of genetic counselors in the United States. However, primary care physicians (PCPs) often have an inadequate understanding of evidence-based screening; communication approaches that encourage shared decision-making; ethical, legal, and social implication (ELSI) issues related to screening for genetic mutations; and the basics of clinical genetics. This study explored whether an interactive, web-based genetics curriculum directed at PCPs in non-academic primary care settings was superior at changing practice knowledge, attitudes, and behaviors when compared to a traditional educational approach, particularly when discussing common genetic conditions.MethodsOne hundred twenty one PCPs in California and Pennsylvania physician practices were randomized to either an Intervention Group (IG) or Control Group (CG). IG physicians completed a 6 h interactive web-based curriculum covering communication skills, basics of genetic testing, risk assessment, ELSI issues and practice behaviors. CG physicians were provided with a traditional approach to Continuing Medical Education (CME) (clinical review articles) offering equivalent information.ResultsPCPs in the Intervention Group showed greater increases in knowledge compared to the Control Group. Intervention PCPs were also more satisfied with the educational materials, and more confident in their genetics knowledge and skills compared to those receiving traditional CME materials. Intervention PCPs felt that the web-based curriculum covered medical management, genetics, and ELSI issues significantly better than did the Control Group, and in comparison with traditional curricula. The Intervention Group felt the online tools offered several advantages, and engaged in better shared decision making with standardized patients, however, there was no difference in behavior change between groups with regard to increases in ELSI discussions between PCPs and patients.ConclusionWhile our intervention was deemed more enjoyable, demonstrated significant factual learning and retention, and increased shared decision making practices, there were few differences in behavior changes around ELSI discussions. Unfortunately, barriers to implementing behavior change in clinical genetics is not unique to our intervention. Perhaps the missing element is that busy physicians need systems-level support to engage in meaningful discussions around genetics issues. The next step in promoting active engagement between doctors and patients may be to put into place the tools needed for PCPs to easily access the materials they need at the point-of-care to engage in joint discussions around clinical genetics

    The Sub-axial Cervical Spine Injury Classification System (SLIC): A Novel Approach to Recognize The Importance of Morphology, Neurology and Integrity of the Disco-ligamentous complex

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    Abstract Background Context Despite technological advances in spine surgery, classification of sub-axial cervical spine injuries remains largely descriptive, lacking standardization and any relationship to prognosis or clinical decision making. Purpose The primary purpose of this paper is to define a classification system for sub-axial cervical spine trauma that conveys information about injury pattern and severity as well as treatment considerations and prognosis. The proposed system is designed to be both comprehensive and easy to use. The secondary objective is to evaluate the classification system in the basic principles of classification construction, namely reliability and validity. Study Design/Setting Derivation of the classification was from a synthesis of the best cervical classification parameters gleaned from an exhaustive literature review and expert opinion of experienced spine surgeons. Multi-center reliability and validity study of a cervical classification system using previously collected CT, MRI, and plain film x-ray images of sub-axial cervical trauma. Methods Important clinical and radiographic variables encountered in sub-axial cervical trauma were identified by a working section of the Spine Trauma Study Group (STSG). Significant limitations of existing injury classification systems were defined and addressed within the new system. It was then introduced to the STSG and applied to 11 cervical trauma cases selected to represent a spectrum of subaxial injury. Six weeks later, the cases were randomly re-ordered and again scored using the novel classification system. Twenty surgeons completed both intervals. Inter-rater and intra-rater reliability and several forms of validity were assessed. For comparison, the reliability of both the Harris and the Ferguson & Allen systems were also evaluated. Results Each of three main categories (injury morphology; disco-ligamentous complex integrity; and neurological status) identified as integrally important to injury description, treatment, and prognosis was assigned an ordinal score range, weighted according to its perceived contribution to overall injury severity. A composite injury severity score was modeled by summing the scores from all three categories. Treatment options were assigned based upon threshold values of the severity score. Inter-rater agreement as assessed by ICC of the DLC, Morphology, and Neurological Status scores was 0.49, 0.57, and 0.87, respectively. Intra-rater agreement as assessed by ICC of the DLC, Morphology, and Neurological Status scores was 0.66, 0.75, and 0.90, respectively. Raters agreed with treatment recommendations of the algorithm in 93.3 % of cases, suggesting high construct validity. The reliability if the SLIC treatment algorithm compared favorably to the earlier classification systems of Harris and Ferguson & Allen. Conclusions The Sub-axial Injury Classification (SLIC) and Severity Scale provides a comprehensive classification system for sub-axial cervical trauma, incorporating pertinent characteristics for generating prognoses and courses of management. Early data on validity and reliability are encouraging. Further testing is necessary before introducing the SLIC score into clinical practice
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