381 research outputs found

    Reconstructing the projected gravitational potential of Abell 1689 from X-ray measurements

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    Context. Galaxy clusters can be used as cosmological probes, but to this end, they need to be thoroughly understood. Combining all cluster observables in a consistent way will help us to understand their global properties and their internal structure. Aims. We provide proof of the concept that the projected gravitational potential of galaxy clusters can directly be reconstructed from X-ray observations. We also show that this joint analysis can be used to locally test the validity of the equilibrium assumptions in galaxy clusters. Methods. We used a newly developed reconstruction method, based on Richardson-Lucy deprojection, that allows reconstructing projected gravitational potentials of galaxy clusters directly from X-ray observations. We applied this algorithm to the well-studied cluster Abell 1689 and compared the gravitational potential reconstructed from X-ray observables to the potential obtained from gravitational lensing measurements. [...] Results. Assuming spherical symmetry and hydrostatic equilibrium, the potentials recovered from gravitational lensing and from X-ray emission agree very well beyond 500 kpc. Owing to the fact that the Richardson-Lucy deprojection algorithm allows deprojecting each line of sight independently, this result may indicate that non-gravitational effects and/or asphericity are strong in the central regions of the clusters. Conclusions. We demonstrate the robustness of the potential reconstruction method based on the Richardson-Lucy deprojection algorithm and show that gravitational lensing and X-ray emission lead to consistent gravitational potentials. Our results illustrate the power of combining galaxy-cluster observables in a single, non-parametric, joint reconstruction of consistent cluster potentials that can be used to locally constrain the physical state of the gas.Comment: 8 pages, 4 figures. Accepted in A&

    Reversible Ionic Liquids as Double-Action Solvents for Efficient CO{sub 2} Capture

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    We have developed a novel class of CO{sub 2} capture solvents, Reversible Ionic Liquids (RevILs), that offer high absorption capacity through two modes of capture: chemical reaction (chemisorption) and physical solubility (physisorption). These solvents are silicon containing alkaline compounds such as silylamines that form a liquid salt (ionic liquid) upon reaction with CO{sub 2}. Subsequently, modest elevations in temperature reverse the reaction and yield pure CO{sub 2} for sequestration. By incorporating Si in the molecules we have reduced the viscosity, thereby improving the mass transfer rates of CO{sub 2} absorption/desorption and decreasing the processing costs for pumping the solvent. In this project, we have made systematic changes to the structure of these compounds to improve several physical and thermodynamic properties important for CO{sub 2} capture. Through these structure-property paradigms, we have obtained a RevIL which requires only a third of the energy required by conventional aqueous MEA process for 90% CO{sub 2} capture

    Supplemental written closing argument - State of Washington

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    Wash. Supplemental Written Closing Argumen

    Adenoma Detection Rate in Asymptomatic Patients with Positive Fecal Immunochemical Tests

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    Background and Aims The adenoma detection rate (ADR) is a powerful measure of screening colonoscopy quality. Patients who undergo colonoscopy for the evaluation of a positive fecal immunochemical test (FIT) have increased prevalence of colorectal neoplasia, but it is not known whether separate quality benchmarks are required. The aim of this study was to compare the conventional ADR to the ADR of colonoscopies performed for the evaluation of positive FIT, in asymptomatic average-risk patients. Methods Patients ≥ 50 years old who underwent colonoscopy for the evaluation of a positive FIT between January 1, 2013, and July 31, 2014, at a tertiary Veterans Affairs Medical Center were identified. FIT performed for any indication other than average-risk screening was excluded. The comparison group included average-risk patients ≥ 50 years old undergoing screening colonoscopy during the same time frame. The two groups were compared for ADR, advanced neoplasm [adenoma ≥ 10 mm, tubulovillous, high-grade dysplasia, CRC, sessile serrated polyp (SSP) ≥ 10 mm], CRC, and SSP detection after propensity score adjustment using a logistic regression model adjusted for endoscopist. Results There were 207 patients in the FIT group and 601 in the screening colonoscopy comparison group. After propensity score adjustment, ADR (72.9 vs. 50.0%, p = 0.003), number of adenomas per colonoscopy (3.3 ± 3.6 vs. 1.4 ± 2.3, p = 0.033), and advanced neoplasm detection rate (32.4 vs. 11.0%, p < 0.0001) were significantly higher in the FIT group. There were no significant differences in the number of CRC and the SSP detection rate. Conclusions In this cohort of average-risk Veterans, the ADR of colonoscopies performed for the evaluation of a positive FIT was higher than the ADR of screening colonoscopies. Patients with a positive FIT also had significantly more adenomas per colonoscopy and advanced neoplasms. These findings suggest that the quality of colonoscopies performed for a positive FIT is insufficiently assessed by the conventional ADR and requires additional quality metrics

    Proposed Findings of fact and conclusions of law (pretrial submission of state of Washington)

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    State of Wash. Proposed Findings of Fact and Conclusions of La

    Written closing argument - State of Washington

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    Wash. Written Closing Argumen

    Prosopis juliflora management and grassland restoration in Baringo County, Kenya: Opportunities for soil carbon sequestration and local livelihoods

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    1. Climate change, land degradation and invasive alien species (IAS) threaten grassland ecosystems worldwide. IAS clearing and grassland restoration would help to reduce the negative effects of IAS, restore the original vegetation cover and sustain livelihoods while contributing to climate change mitigation, but uncertain financial benefits to local stakeholders hamper such efforts. This study assessed where and when net financial benefit could be realized from Prosopis juliflora management and subsequent grassland restoration by combining ecological, social and financial information. 2. Impacts of Prosopis invasion and grassland degradation on soil organic carbon (SOC) in nine sublocations in Baringo County, Kenya, were evaluated. Then the financial impacts of Prosopis removal and grassland restoration in the area were calculated and spatially explicit management scenarios for each sublocation modelled, combining geographical information derived from satellite images taken in different years of the invasion with SOC data and socio-economic data collected in the sublocations. 3. The expanding Prosopis distribution and density since 1995 have increased cumulated SOC storage on former bare land or degraded grasslands. On former pristine or restored grasslands, however, Prosopis invasion has reduced total SOC storage. 4. Prosopis removal and grassland restoration are predicted to yield financial benefits through charcoal made from removed trees, increased cattle numbers and carbon credits. However, a trade-off between increased SOC and net financial benefit was found. The predicted net SOC increase would contribute around one-tenth, at most, to the net financial benefit. 5. The available budget, based on Baringo households’ average willingness to pay, would enable removal, on average, of one-fifth of Prosopis per sublocation in a single year. A larger area can be cleared if Prosopis is sparse than if it is dense. The analyses show that in some sublocations, households’ annual investments could result in restoration of all former grassland areas. 6. Synthesis and applications. This study shows how integrating and linking detailed ecological, social and financial geodata to develop accurate and realistic invasive alien species management scenarios can illustrate costs and benefits of management interventions in a spatial context. Such scenarios should be used more extensively to support land management decisions

    Defining adenoma detection rate benchmarks in average-risk male veterans

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    Background and Aims Veterans have higher prevalence of colorectal neoplasia than non-veterans; however, it is not known whether specific Veterans Affairs (VA) adenoma detection rate (ADR) benchmarks are required. We compared ADRs of a group of endoscopists for colonoscopies performed at a VA to their ADRs at a non-VA academic medical center. Methods This was a retrospective review of screening colonoscopies performed by endoscopists who practice at the Indianapolis VA and Indiana University (IU). Patients were average-risk males aged 50 years or older. ADR, proximal adenoma detection rate, advanced adenoma detection rate, and adenomas per colonoscopy were compared between IU and the VA groups. Results Six endoscopists performed screening colonoscopies at both locations during the study period (470 at IU vs 608 at the VA). The overall ADR was not significantly different between IU and the VA (58% vs 61%; p =0.21). Advanced neoplasia detection rate (13% vs 17%; p=0.46), proximal adenoma detection rate (46% vs 47%; p=0.31), and adenoma per colonoscopy (1.59 vs 1.84; p=0.24) were not significantly different. There were no significant differences in cecal intubation rate (100% vs 99%; p=0.13) or withdrawal time (10.9 vs 11.1 min; p=0.28). In regression analysis, there was significant correlation between the attending-specific ADRs at IU and the VA (p=0.041, r-square=0.69). Conclusions In this study of average-risk males undergoing screening colonoscopies by the same group of endoscopists, the ADRs of VA and non-VA colonoscopies were not significantly different. This suggests that a VA-specific ADR target is not required for endoscopists with high ADR
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