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Akaganeite (beta-FeOOH) is an Fe(III) (hydr)oxide with a tunnel structure usually occupied by chloride. Akaganeite has been recently discovered in a mudstone on the surface of Mars by the Chemistry and Mineralogy (CheMin) and Samp...
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Akaganeite (beta-FeOOH) is an Fe(III) (hydr)oxide with a tunnel structure usually occupied by chloride. Akaganeite has been recently discovered in a mudstone on the surface of Mars by the Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) instruments onboard the Mars Science Laboratory (MSL) Curiosity Rover in Gale crater [1, 2]. Akaganeite was detected together with sulfate minerals [anhydrite (CaSO4) and basanite (2CaSO4·2H2O)] in the drilled Cumberland and John Clein mudstone samples at Yellowknife Bay [2]. Discovery of akaganeite and sulfates in the same samples suggests that sulfate ions could be present in aqueous solution during akaganeite formation. However, mechanism and aqueous environmental conditions of akaganeite formation (e.g., pH and range of sulfate concentration) in Yellowknife Bay remain unknown. The objective of our work was to perform synthesis of akaganeite without or with sulfate addition at variable pHs in order to constrain formation conditions of akaganeite in Yellowknife Bay, Gale crater on Mars.
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Dengue virus transmission occurs in both epidemic and endemic cycles across tropical and sub-tropical regions of the world. Incidence is particularly high in much of Southeast Asia, where hyperendemic transmission plagues both urb...
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Dengue virus transmission occurs in both epidemic and endemic cycles across tropical and sub-tropical regions of the world. Incidence is particularly high in much of Southeast Asia, where hyperendemic transmission plagues both urban and rural populations. However, endemicity has not been established in some areas with climates that may not support yearround viral transmission. An understanding of how dengue viruses (DENV) enter these environments and whether the viruses persist in inapparent local transmission cycles is central to understanding how dengue emerges in areas at the margins of endemic transmission. Dengue is highly endemic in tropical southern Vietnam, while increasingly large seasonal epidemics have occurred in northern Viet Nam over the last decade. We have investigated the spread of DENV-1 throughout Vietnam to determine the routes by which the virus enters northern and central regions of the country. Phylogeographic analysis of 1,765 envelope (E) gene sequences from Southeast Asia revealed frequent movement of DENV between neighboring human populations and strong local clustering of viral lineages. Long-distance migration of DENV between human population centers also occurred regularly and on short time-scales, indicating human-mediated viral invasion into northern Vietnam. Human populations in southern Vietnam were found to be the primary source of DENV circulating throughout the country, while central and northern Vietnam acted as sink populations, likely due to reduced connectedness to other populations in the case of the central regions and to the influence of temperature variability on DENV replication and vector survival and competence in the north. Finally, phylogeographic analyses suggested that viral movement follows a gravity model and indicates that population immunity and physical and economic connections between populations may play important roles in shaping patterns of DENV transmission.
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This white paper discusses the motivation and issues surrounding the development of a repository and associated computational infrastructure to house and process a million genomes to help battle cancer, which we call the Million C...
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This white paper discusses the motivation and issues surrounding the development of a repository and associated computational infrastructure to house and process a million genomes to help battle cancer, which we call the Million Cancer Genome Warehouse. It is proposed as an example of an information commons and a computing system that will bring about precision medicine, coupling established clinical pathological indexes with state-of-the-art molecular profiling to create diagnostic, prognostic, and therapeutic strategies precisely tailored to each patient's individual requirements. The goal of the white paper is to stimulate discussion so as to help reach consensus about the need to construct a Million Cancer Genome Warehouse and what its nature should be. To try to anticipate concerns, including thorough cost estimates, it covers topics as varied as high-level health policy issues to low-level details about statistical analysis, data formats and structures, software design, and hardware construction and cost.
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Upcoming experiments aim to produce high fidelity polarization maps of the cosmic microwave background. To achieve the required sensitivity, we are developing monolithic, feedhorn-coupled transition edge sensor polarimeter arrays ...
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Upcoming experiments aim to produce high fidelity polarization maps of the cosmic microwave background. To achieve the required sensitivity, we are developing monolithic, feedhorn-coupled transition edge sensor polarimeter arrays operating at 150 GHz. We describe this focal plane architecture and the current status of this technology, focusing on single-pixel polarimeters being deployed on the Atacama B-mode Search (ABS) and an 84-pixel demonstration feedhorn array backed by four 10-pixel polarimeter arrays. The feedhorn array exhibits symmetric beams, cross-polar response less than -23 dB and excellent uniformity across the array. Monolithic polarimeter arrays, including arrays of silicon feedhorns, will be used in the Atacama Cosmology Telescope Polarimeter (ACTPol) and the South Pole Telescope Polarimeter (SPTpol) and have been proposed for upcoming balloon-borne instruments.
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This paper is part of a multi-year effort undertaken by the Bureau of Justice Assistance and the Center for Court Innovation to stimulate new thinking about criminal justice innovation. By examining the trials of past reform effor...
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This paper is part of a multi-year effort undertaken by the Bureau of Justice Assistance and the Center for Court Innovation to stimulate new thinking about criminal justice innovation. By examining the trials of past reform efforts, this investigation seeks to encourage a more open and honest dialogue about the criminal justice system and what it can realistically be expected to achieve-and to help tomorrow's innovators avoid the mistakes of yesterday's. Since its inception in Los Angeles in 1983, Drug Abuse Resistance Education (D.A.R.E.) has become one of the most well-known and widespread crime prevention programs in the country. D.A.R.E.'s model is relatively straightforward. Police officers are trained to lead educational sessions in local schools that are designed to help students resist peer pressure and live drug-free lives. The program's reach is nothing short of remarkable: D.A.R.E. has been responsible for training hundreds of thousands of police officers and educating millions of children. The program has spread to 43 different countries. In recognition of this, every year for the last 18 years, four consecutive presidents have set aside a day in April as 'National D.A.R.E. Day.' Alongside this impressive track record, however, there exists a counter-narrative. This story is written not by the administrators of D.A.R.E. but by scholars who have studied the program. To date, there have been more than 30 evaluations of the program that have documented negligible long-term impacts on teen drug use. One intensive, six-year study even found that the program increased drug use among suburban teens by a small amount. Despite these setbacks, D.A.R.E. is alive and well, taught in about 75 percent of school districts across the country. Over 15,000 police officers participate as D.A.R.E.
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Weaknesses in trade-related transport and logistics, particularly in developing countries, impose costs on producers that erode the intended benefits of trade preferences in major markets, such as the United States and the Europea...
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Weaknesses in trade-related transport and logistics, particularly in developing countries, impose costs on producers that erode the intended benefits of trade preferences in major markets, such as the United States and the European Union. In fact, the cost of such weaknesses may be many times greater than the benefit of preferences. Accordingly, trade capacity-building assistance should address these logistical and transport weaknesses so developing countries can join the global economy. Among weaknesses that need to be addressed, port inefficiencies may be the most serious and least understood. Improving ports can lower total transaction costs and boost the competitiveness of a countrys exportsand in the long run create jobs, spur growth, and improve general welfare. Studies relating port costs to national competitiveness have consistently shown a strong relationship between port efficiency and the cost of traded products. Until now, such studies have not made concrete linkages to the sources of those efficiencies, or attempted to quantify the effects of specific types of inefficient practices, much less calculate the overall trade and welfare effects of such inefficiencies, as we do in the original research presented here. In this study, we analyze the operation of a port challenged by congestion, Puerto Limon (in Costa Rica), comparing it with a port known for its efficient operations, Cartagena (in Colombia). We compare the cost and performance of Cartagena with that of Puerto Limon by determining vessel berth and cargo dwell times and by sailing a model ship through our port tariff model. We then examine and explain processing procedures for each instance in which processing times in the inefficient port exceed those in the efficient one. This comparison enables us to identify factors that contribute directly and indirectly to the relatively high cost of using the Puerto Limon port facilities.
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