4,402 research outputs found
Distinguishing low frequency mutations from RT-PCR and sequence errors in viral deep sequencing data
There is a high prevalence of coronary artery disease (CAD) in patients with left bundle branch block (LBBB); however there are many other causes for this electrocardiographic abnormality. Non-invasive assessment of these patients remains difficult, and all commonly used modalities exhibit several drawbacks. This often leads to these patients undergoing invasive coronary angiography which may not have been necessary. In this review, we examine the uses and limitations of commonly performed non-invasive tests for diagnosis of CAD in patients with LBBB
B707: Analysis of Waste Disposal Problems Related to Maine Poultry Processing Plants
This study analyzed waste disposal problems related to Maine poultry processing plants. The problems of the Maine plants are quite typical of those found in the industry outside Maine. Two exceptions to this generality are amount of water used and cost of replacement and operation of the treatment facility. Maine plants appear to use more water than plants located in competing areas but they are of larger average size and have access to municipal water supplies and therefore are not particularly disadvantaged.https://digitalcommons.library.umaine.edu/aes_bulletin/1072/thumbnail.jp
Habitat fragmentation reduces survival and drives source–sink dynamics for a large carnivore
Rigorous understanding of how environmental conditions impact population dynamics is essential for species conservation, especially in mixed-use landscapes where source–sink dynamics may be at play. Conservation of large carnivore populations in fragmented, human-dominated landscapes is critical for their long-term persistence. However, living in human-dominated landscapes comes with myriad costs, including direct anthropogenic mortality and sublethal energetic costs. How these costs impact individual fitness and population dynamics are not fully understood, partly due to the difficulty in collecting long-term demographic data for these species. Here, we analyzed an 11-year dataset on puma (Puma concolor) space use, mortality, and reproduction in the Santa Cruz Mountains, California, USA, to quantify how living in a fragmented landscape impacts individual survival and population dynamics. Long-term exposure to housing density drove mortality risk for female pumas, resulting in an 18-percentage-point reduction in annual survival for females in exurban versus remote areas. While the overall population growth rate appeared stable, reduced female survival in more developed areas resulted in source–sink dynamics across the study area, with 42.1% of the Santa Cruz Mountains exhibiting estimated population growth rates \u3c1. Since habitat selection is often used as a proxy for habitat quality, we also assessed whether puma habitat selection predicted source and sink areas. Patterns of daytime puma habitat selection predicted source areas, while time-of-day-independent habitat selection performed less well as a proxy. These results illuminate the individual- and population-level consequences of habitat fragmentation for large carnivores, illustrating that habitat fragmentation can produce source– sink dynamics that may not be apparent from other metrics of habitat quality. Locally, conserving high-quality source habitat within the Santa Cruz Mountains is necessary to support long-term puma population persistence. More broadly, source–sink dynamics may at play for other carnivore populations in similar fragmented systems, and linking landscape condition
B816: An Economic Analysis of a Maine Dairy Farm Anaerobic Digester
Anaerobic digestion is a method for decomposing organic matter, producing in the process, biogas, which is mostly methane. This process can be used to eliminate or reduce disagreeable and often environmentally harmful characteristics of wastes. During the autumn of 1984, the University of Maine began operation of an anaerobic digestion unit acquired from Agway, Inc., a large Northeastern agricultural cooperative. This system, installed at the Witter Animal Science Center, decomposes animal manures and ultimately produces electricity and hot water. A by-product of the system is a fertilizer with characteristics superior to fertilizers produced from biological wastes that have not undergone a process of anaerobic digestion. The research objectives were to (1) construct an economic-engineering model representing the waste to energy system, (2) quantify the benefits and costs of the system, (3) estimate the cash flows accruing over the lifespan of the system, (4) evaluate the model to determine the net present value of the system, and (5) evaluate alternative scenarios to determine the effect on economic feasibility.https://digitalcommons.library.umaine.edu/aes_bulletin/1051/thumbnail.jp
B796: A Comparison of Direct Market Users and Nonusers Habits, Acceptance, and Preferences for Direct Marketed Small Farms Horticulture Commodities
Until recently small scale farming has been considered inefficient and undesirable. Small farmers have found it difficult to compete with large operators in the market place because of their inability to provide a significant quantity of product over an extended period of time to meet the needs of large scale marketing firms. According to the 1978 Census of Agriculture small farms, those with sales under $40,000, account for nearly 76 percent of the farms in Maine. Therefore, a market system has developed which is not amenable to the small farmer who represents a significant segment of Northeast agriculture.
Though the formal marketing system has become relatively inaccessible to the small farmer, changes in the American consumer\u27s preferences offer the small farmer hope. In the late 1960s and through the 1970s it became evident that food buying behavior of consumers across the nation was changing. It appeared that consumer food preferences changed, with quality factors such as freshness and taste, growing methods and packaging, and nutrition becoming important to more people. The objective of this paper was to determine direct market users and non-users habits, levels of acceptance, and preferences for direct marketed small farm horticultural commodities in Maine.https://digitalcommons.library.umaine.edu/aes_bulletin/1105/thumbnail.jp
Parent perceptions of a child physical activity initiative in a rural community.
This study assessed the extent to which a community-based intervention developed for children impacted parent perceptions and behaviors toward physical activity in a rural community. Focus groups and individual interviews were conducted with parents of children who participated in physical activity programs. Analysis revealed an increased community awareness surrounding physical activity following program implementation. Parents and children encouraged each other to be physically active. Ecological barriers and enabling factors to adult physical activity were identified these findings indicate a bidirectional influence between parent and child physical activity and the need for community facilities where families can be active together
Rhenium Complexes Bearing Tridentate and Bidentate Phosphinoamine Ligands in the Production of Biofuel Alcohols via the Guerbet Reaction
We report a variety of rhenium complexes supported by bidentate and tridentate phosphinoamine ligands and their use in the formation of the advanced biofuel isobutanol from methanol and ethanol. Rhenium pincer complexes 1–3 are effective catalysts for this process, with 2 giving isobutanol in 35% yields, with 97% selectivity in the liquid fraction, over 16 h with catalyst loadings as low as 0.07 mol %. However, these catalysts show poorer overall selectivity, with the formation of a significant amount of carboxylate salt solid byproduct also being observed. Production of the active catalyst 1d has been followed by 31P NMR spectroscopy, and the importance of the presence of base and elevated temperatures to catalyst activation has been established. Complexes supported by diphosphine ligands are inactive for Guerbet chemistry; however, complexes supported by bidentate phosphinoamine ligands show greater selectivity for isobutanol formation over carboxylate salts. The novel complex 7 was able to produce isobutanol in 28% yield over 17 h. The importance of the N–H moiety to the catalytic performance has also been established, giving further weight to the hypothesis that these catalysts operate via a cooperative mechanism
Tribimaximal Neutrino Mixing from A_4 Replication
Motivated by dimensional deconstruction, we propose a model of tribimaximal
neutrino mixing based on A_4 x A_4 symmetry. In this model, the two triplet
symmetry-breaking fields of conventional A_4 models are taken to transform
under different A_4 group factors, but are not distinguished by any other
quantum numbers. An additional bi-triplet flavon field breaks A_4 x A_4 to its
diagonal subgroup. If the bi-triplet transforms under an additional Z_3
symmetry, we show that one can construct a general, renormalizable
superpotential that yields the desired pattern of symmetry breaking. We
identify the features that this model has in common with a deconstructed 5D
theory in which A_4 is a subgroup of a continuous gauged flavor symmetry in the
bulk.Comment: 13 pages LaTeX (v2: discussion added
Constraints on Natural MNS Parameters from |U_e3|
The MNS matrix structure emerging as a result of recent neutrino measurements
strongly suggests two large mixing angles (solar and atmospheric) and one small
angle (|U_e3| << 1). Especially when combined with the neutrino mass hierarchy,
these values turn out to impose rather stringent constraints on possible flavor
models connecting the three active fermion generations. Specifically, we show
that an extremely small value of |U_e3| would require fine tuning of Majorana
mass matrix parameters, particularly in the context of seesaw models.Comment: 21 pages, ReVTeX, 2 .eps figure files, updated references and
acknowledgment
Recommended from our members
Argonne National Laboratory Reports
This report describes a computer program, called ANL/HIWAY, for estimating air quality levels of nonreactive pollutants produced by vehicular sources. It is valid for receptors at distances of tens to hundreds of meters, at an angle, downwind of the roadway, in relatively uncomplicated terrain. It may be used by planners to analyze the effects of a proposed roadway on adjacent air quality. The ANL/HIWAY model expands the evaluation capabilities of the EPA/HIWAY dispersion model. This report also serves as a user's manual for running the ANL/HIWAY PROGRAM. All command structures are described in detail, with sample problems exemplifying their use
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