459 research outputs found
Economics analysis of mitigation strategies for FMD introduction in highly concentrated animal feeding regions
Outbreaks of infectious animal diseases can lead to substantial losses as evidenced by 2003 US BSE (Bovine Spongiform Encephalopathy) event with consequent loss of export markets, and the 2001 UK FMD (Foot and Mouth Disease) outbreak that has cost estimates in the billions. In this paper we present a linked epidemiologic-economic modeling framework which is used to investigate several FMD mitigation strategies under the context of an FMD outbreak in a concentrated cattle feeding region in the US. In this study we extend the literature by investigating the economic effectiveness of some previously unaddressed strategies including early detection, enhanced vaccine availability, and enhanced surveillance under various combinations of slaughter, surveillance, and vaccination. We also consider different disease introduction points at a large feedlot, a backgrounder feedlot, a large grazing herd, and a backyard herd all in the Texas High Plains. In terms of disease mitigation strategies we evaluate the economic effectiveness of: 1. Speeding up initial detection by one week from day 14 to day 7 after initial infection; 2. Speeding up vaccine availability from one week post disease detection to the day of disease detection; 3.Doubling post event surveillance intensity. To examine the economic implications of these strategies we use a two component stochastic framework. The first component is the epidemiologic model that simulates the spread of FMD as affected by control policies and introduction scenarios. The second component is an economics module, which calculates an estimate of cattle industry losses plus the costs of implementing disease control. The results show that early detection of the disease is the most effective mechanism for minimizing the costs of outbreak. Under some circumstances enhanced surveillance also proved to be an effective strategy.Livestock Production/Industries,
Experimental investigation and simplistic geochemical modeling of CO2 mineral carbonation using the mount tawai peridotite
In this work, the potential of CO2 mineral carbonation of brucite (Mg(OH)2) derived from the Mount Tawai peridotite (forsterite based (Mg)2SiO4) to produce thermodynamically stable magnesium carbonate (MgCO3) was evaluated. The effect of three main factors (reaction temperature, particle size, and water vapor) were investigated in a sequence of experiments consisting of aqueous acid leaching, evaporation to dryness of the slurry mass, and then gas-solid carbonation under pressurized CO2. The maximum amount of Mg converted to MgCO3 is âŒ99%, which occurred at temperatures between 150 and 175 °C. It was also found that the reduction of particle size range from >200 to <75 ÎŒm enhanced the leaching rate significantly. In addition, the results showed the essential role of water vapor in promoting effective carbonation. By increasing water vapor concentration from 5 to 10 vol %, the mineral carbonation rate increased by 30%. This work has also numerically modeled the process by which CO2 gas may be sequestered, by reaction with forsterite in the presence of moisture. In both experimental analysis and geochemical modeling, the results showed that the reaction is favored and of high yield; going almost to completion (within about one year) with the bulk of the carbon partitioning into magnesite and that very little remains in solution
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Molecular and phylogenetic analysis reveals new diversity of Dunaliella salina from hypersaline environments.
Twelve hyper-ÎČ carotene-producing strains of algae assigned to the genus Dunaliella salina have been isolated from various hypersaline environments in Israel, South Africa, Namibia and Spain. Intron-sizing of the SSU rDNA and phylogenetic analysis of these isolates were undertaken using four commonly employed markers for genotyping, LSU rDNA, ITS, rbcL and tufA and their application to the study of Dunaliella evaluated. Novel isolates have been identified and phylogenetic analyses have shown the need for clarification on the taxonomy of Dunaliella salina. We propose the division of D. salina into four sub-clades as
defined by a robust phylogeny based on the concatenation of four genes. This study further demonstrates the considerable genetic diversity within D. salina and the potential of genetic analyses for aiding in the selection of prospective economically important strains
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The visual complexity of coronal mass ejections follows the solar cycle
The Heliospheric Imagers on board National Aeronautics and Space Administration (NASA)'s
twin STEREO spacecraft show that coronal mass ejections (CMEs) can be visually complex structures. To
explore this complexity, we created a citizen science project with the U.K. Science Museum, in which
participants were shown pairs of CME images and asked to decide which image in each pair appeared the
most âcomplicated.â A BradleyâTerry model was then applied to these data to rank the CMEs by their
âcomplicatedness,â or âvisual complexity.â This complexity ranking revealed that the annual average visual
complexity values follow the solar activity cycle, with a higher level of complexity being observed at the peak
of the cycle. The average complexity of CMEs observed by STEREOâA was also found to be significantly
higher than those observed by STEREOâB. Visual complexity was found to be associated with CME size and
brightness, but our results suggest that complexity may be influenced by the scaleâsizes of structure in the
CMEs
In-situ drift spectroscopy in a continuous recycle reactor: a versatile tool for catalytic process research
Diffuse Reflectance IR Fourier-Transform (DRIFT) spectroscopy is an increasingly popular technique in catalysis research as it permits in situ observation of the reactor bed in powd. or granular form. However, DRIFTS in its conventional form suffers from temp.-gradient problems. One soln. is to couple the DRIFTS cell with a continuous recycle flow system. The value of such an arrangement is illustrated via studies of the kinetics and mechanism of CO2 methanation over Ru/TiO2 under transient and steady-state conditions. Metal-absorbed CO is identified as the main reaction intermediate through titrn. to CH4 in transient hydrogenation. The COad is probably supplied via rapid establishment of the reverse water gas shift equil.: H2 + CO2 -> COad + H2O involving adsorbed formate intermediate(s). [on SciFinder (R)
Interactive web-based mapping: bridging technology and data for health
BACKGROUND: The Community Health Information System (CHIS) online mapping system was first launched in 1998. Its overarching goal was to provide researchers, residents and organizations access to health related data reflecting the overall health and well-being of their communities within the Greater Houston area. In September 2009, initial planning and development began for the next generation of CHIS. The overarching goal for the new version remained to make health data easily accessible for a wide variety of research audiences. However, in the new version we specifically sought to make the CHIS truly interactive and give the user more control over data selection and reporting. RESULTS: In July 2011, a beta version of the next-generation of the application was launched. This next-generation is also a web based interactive mapping tool comprised of two distinct portals: the Breast Health Portal and Project Safety Net. Both are accessed via a Google mapping interface. Geographic coverage for the portals is currently an 8 county region centered on Harris County, Texas. Data accessed by the application include Census 2000, Census 2010 (underway), cancer incidence from the Texas Cancer Registry (TX Dept. of State Health Services), death data from Texas Vital Statistics, clinic locations for free and low-cost health services, along with service lists, hours of operation, payment options and languages spoken, uninsured and poverty data. CONCLUSIONS: The system features query on the fly technology, which means the data is not generated until the query is provided to the system. This allows users to interact in real-time with the databases and generate customized reports and maps. To the author's knowledge, the Breast Health Portal and Project Safety Net are the first local-scale interactive online mapping interfaces for public health data which allow users to control the data generated. For example, users may generate breast cancer incidence rates by Census tract, in real time, for women aged 40-64. Conversely, they could then generate the same rates for women aged 35-55. The queries are user controlled
The requirement for external carbonic anhydrase in diatoms is influenced by the supply and demand for dissolved inorganic carbon
Photosynthesis by marine diatoms contributes significantly to the global carbon cycle. Due to the low concentration of CO2 in seawater, many diatoms use extracellular carbonic anhydrase (eCA) to enhance the supply of CO2 to the cell surface. While much research has investigated how the requirement for eCA is influenced by changes in CO2 availability, little is known about how eCA contributes to CO2 supply following changes in the demand for carbon. We therefore examined how changes in photosynthetic rate influence the requirement for eCA in three centric diatoms. Modeling of cell surface carbonate chemistry indicated that diffusive CO2 supply to the cell surface was greatly reduced in large diatoms at higher photosynthetic rates. Laboratory experiments demonstrated a trend of an increasing requirement for eCA with increasing photosynthetic rate that was most pronounced in the larger species, supporting the findings of the cellular modeling. Microelectrode measurements of cell surface pH and O2 demonstrated that individual cells exhibited an increased contribution of eCA to photosynthesis at higher irradiances. Our data demonstrate that changes in carbon demand strongly influence the requirement for eCA in diatoms. Cell size and photosynthetic rate will therefore be key determinants of the mode of dissolved inorganic carbon uptake
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