98 research outputs found

    Shoreline recession: past, present, and future, Lake Sakakawea, North Dakota

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    Shoreline erosion is a major problem at Lake Sakakawea, North Dakota. Instrumentation along the eastern shore was initiated in 1983 to measure shoreline recession and determine the processes responsible, with the ultimate goal being the development of a relatively simple equation to predict the rate of recession which is better than the model currently used by the U.S. Army Corps of Engineers. For the twenty stations, the present rate of recession ranges from 0.2 to 4.3 m/y. Approximately 78 percent of the yearly recession occurs during the warm months (May-October) due to wave erosion. Erosion over the cold months occurs as a result of thaw failure. The most important variables associated with shoreline recession include: bank height, effective fetch, offshore slope angle, beach width, mean grain size, percentage of coarse beach clasts, angle between the shoreline and dominant wind, and bank orientation with respect to the sun. These variables, along with the average monthly rate of recession, were submitted to regression analysis. Because the rates of recession are seasonally dependent a separate equation was developed for warm and cold season recession. The warm season recession equation, in cm/mo, is: 1a) Rs = 141.53 – [17.2√A + 8.44√B + 25.08√C + 10.4√D] where A= angle between the dominant wind and the shoreline, B= bank height, C= offshore slope angle, and D= beach width. This equation exceeds the 95 percent confidence level with an r² of 59.3 percent. This equation is preferred to equation 1b: 1b) Rs=154.9-[18.8√A + 25.12√B + 10.06√C + 6.91√D + 5.03√E + 1.1√F] which includes effective fetch (E) and percentage of coarse clasts (F). This equation exceeds the 75 percent confidence level only. Both equations, however, produce similar results. The cold season rate is: 2) Rw = Rs [(2.05 (bank height) + 0.043 (bank orientation) - 2)/100, where bank orientation is with respect to the sun. This analysis exceeds the 99 percent confidence level and produces an r² of 46 percent. The yearly rate of recession (cm/yr) is the sum of the warm and cold season recession multiplied by their active months. 3) Rt= 6(Rs) + 6(Rw) For future bank recession it was assumed that the rate of recession will decrease with time. Thus, an equation was developed that incorporated the present yearly recession rate and the formula for a parabola. Recession calculated from the equations predicts cumulative recession up to 495m over the 500-year life of the reservoir. Although these equations are a significant improvement over the template method in use by the U.S. Army Corps of Engineers, further testing is necessary to determine their applicability to other inland bodies of water

    Diagnostic criteria for multiple sclerosis: 2010 Revisions to the McDonald criteria

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    New evidence and consensus has led to further revision of the McDonald Criteria for diagnosis of multiple sclerosis. The use of imaging for demonstration of dissemination of central nervous system lesions in space and time has been simplified, and in some circumstances dissemination in space and time can be established by a single scan. These revisions simplify the Criteria, preserve their diagnostic sensitivity and specificity, address their applicability across populations, and may allow earlier diagnosis and more uniform and widespread use. Ann Neurol 201

    MAVS-Mediated Apoptosis and Its Inhibition by Viral Proteins

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    BACKGROUND: Host responses to viral infection include both immune activation and programmed cell death. The mitochondrial antiviral signaling adaptor, MAVS (IPS-1, VISA or Cardif) is critical for host defenses to viral infection by inducing type-1 interferons (IFN-I), however its role in virus-induced apoptotic responses has not been elucidated. PRINCIPAL FINDINGS: We show that MAVS causes apoptosis independent of its function in initiating IFN-I production. MAVS-induced cell death requires mitochondrial localization, is caspase dependent, and displays hallmarks of apoptosis. Furthermore, MAVS(-/-) fibroblasts are resistant to Sendai virus-induced apoptosis. A functional screen identifies the hepatitis C virus NS3/4A and the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) nonstructural protein (NSP15) as inhibitors of MAVS-induced apoptosis, possibly as a method of immune evasion. SIGNIFICANCE: This study describes a novel role for MAVS in controlling viral infections through the induction of apoptosis, and identifies viral proteins which inhibit this host response

    Henry Versus Thompson Approach for Fixation of Proximal Third Radial Shaft Fractures: A Multicenter Study

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    Objective: To compare the volar Henry and dorsal Thompson approaches with respect to outcomes and complications for proximal third radial shaft fractures. Design: Multicenter retrospective cohort study. Patients/Participants: Patients with proximal third radial shaft fractures ± associated ulna fractures (OTA/AO 2R1 ± 2U1) treated operatively at 11 trauma centers were included. Intervention: Patient demographics and injury, fracture, and surgical data were recorded. Final range of motion and complications of infection, neurologic injury, compartment syndrome, and malunion/nonunion were compared for volar versus dorsal approaches. Main Outcome: The main outcome was difference in complications between patients treated with volar versus dorsal approach. Results: At an average follow-up of 292 days, 202 patients (range, 18–84 years) with proximal third radial shaft fractures were followed through union or nonunion. One hundred fifty-five patients were fixed via volar and 47 via dorsal approach. Patients treated via dorsal approach had fractures that were on average 16 mm more proximal than those approached volarly, which did not translate to more screw fixation proximal to the fracture. Complications occurred in 11% of volar and 21% of dorsal approaches with no statistical difference. Conclusions: There was no statistical difference in complication rates between volar and dorsal approaches. Specifically, fixation to the level of the tuberosity is safely accomplished via the volar approach. This series demonstrates the safety of the volar Henry approach for proximal third radial shaft fractures

    Unsupervised assessment of microarray data quality using a Gaussian mixture model

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    <p>Abstract</p> <p>Background</p> <p>Quality assessment of microarray data is an important and often challenging aspect of gene expression analysis. This task frequently involves the examination of a variety of summary statistics and diagnostic plots. The interpretation of these diagnostics is often subjective, and generally requires careful expert scrutiny.</p> <p>Results</p> <p>We show how an unsupervised classification technique based on the Expectation-Maximization (EM) algorithm and the naïve Bayes model can be used to automate microarray quality assessment. The method is flexible and can be easily adapted to accommodate alternate quality statistics and platforms. We evaluate our approach using Affymetrix 3' gene expression and exon arrays and compare the performance of this method to a similar supervised approach.</p> <p>Conclusion</p> <p>This research illustrates the efficacy of an unsupervised classification approach for the purpose of automated microarray data quality assessment. Since our approach requires only unannotated training data, it is easy to customize and to keep up-to-date as technology evolves. In contrast to other "black box" classification systems, this method also allows for intuitive explanations.</p

    Global gene expression profile progression in Gaucher disease mouse models

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    <p>Abstract</p> <p>Background</p> <p>Gaucher disease is caused by defective glucocerebrosidase activity and the consequent accumulation of glucosylceramide. The pathogenic pathways resulting from lipid laden macrophages (Gaucher cells) in visceral organs and their abnormal functions are obscure.</p> <p>Results</p> <p>To elucidate this pathogenic pathway, developmental global gene expression analyses were conducted in distinct <it>Gba1 </it>point-mutated mice (V394L/V394L and D409 V/null). About 0.9 to 3% of genes had altered expression patterns (≥ ± 1.8 fold change), representing several categories, but particularly macrophage activation and immune response genes. Time course analyses (12 to 28 wk) of INFγ-regulated pro-inflammatory (13) and IL-4-regulated anti-inflammatory (11) cytokine/mediator networks showed tissue differential profiles in the lung and liver of the <it>Gba1 </it>mutant mice, implying that the lipid-storage macrophages were not functionally inert. The time course alterations of the INFγ and IL-4 pathways were similar, but varied in degree in these tissues and with the <it>Gba1 </it>mutation.</p> <p>Conclusions</p> <p>Biochemical and pathological analyses demonstrated direct relationships between the degree of tissue glucosylceramides and the gene expression profile alterations. These analyses implicate IFNγ-regulated pro-inflammatory and IL-4-regulated anti-inflammatory networks in differential disease progression with implications for understanding the Gaucher disease course and pathophysiology.</p
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