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Search Results: 1 - 10 of 84648 matches for " Clinton W. Epps "
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Local Extinction and Unintentional Rewilding of Bighorn Sheep (Ovis canadensis) on a Desert Island
Benjamin T. Wilder, Julio L. Betancourt, Clinton W. Epps, Rachel S. Crowhurst, Jim I. Mead, Exequiel Ezcurra
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091358
Abstract: Bighorn sheep (Ovis canadensis) were not known to live on Tiburón Island, the largest island in the Gulf of California and Mexico, prior to the surprisingly successful introduction of 20 individuals as a conservation measure in 1975. Today, a stable island population of ~500 sheep supports limited big game hunting and restocking of depleted areas on the Mexican mainland. We discovered fossil dung morphologically similar to that of bighorn sheep in a dung mat deposit from Mojet Cave, in the mountains of Tiburón Island. To determine the origin of this cave deposit we compared pellet shape to fecal pellets of other large mammals, and extracted DNA to sequence mitochondrial DNA fragments at the 12S ribosomal RNA and control regions. The fossil dung was 14C-dated to 1476–1632 calendar years before present and was confirmed as bighorn sheep by morphological and ancient DNA (aDNA) analysis. 12S sequences closely or exactly matched known bighorn sheep sequences; control region sequences exactly matched a haplotype described in desert bighorn sheep populations in southwest Arizona and southern California and showed subtle differentiation from the extant Tiburón population. Native desert bighorn sheep previously colonized this land-bridge island, most likely during the Pleistocene, when lower sea levels connected Tiburón to the mainland. They were extirpated sometime in the last ~1500 years, probably due to inherent dynamics of isolated populations, prolonged drought, and (or) human overkill. The reintroduced population is vulnerable to similar extinction risks. The discovery presented here refutes conventional wisdom that bighorn sheep are not native to Tiburón Island, and establishes its recent introduction as an example of unintentional rewilding, defined here as the introduction of a species without knowledge that it was once native and has since gone locally extinct.
Achievement of Climate Planning Objectives among U.S. Member Cities of the International Council for Local Environmental Initiatives (ICLEI)  [PDF]
Margaret A. Reams, Kelsey W. Clinton, Nina S. N. Lam
Low Carbon Economy (LCE) , 2012, DOI: 10.4236/lce.2012.34018
Abstract:

In an effort to address climate change, many cities have joined the International Council for Local Environmental Initiatives (ICLEI) whose members commit to work toward five specific program objectives designed to reduce greenhouse gas emissions. This study examines the extent to which 257 member cities in the U.S.have been successful in achieving these program milestones and identifies factors that may explain variation in the performance of member cities. Potential influences on milestone attainment include socioeconomic, political and ideological characteristics of residents, length of ICLEI membership, existence of other climate programs within the state, and local environmental pressures. Multiple regression results indicate that length of membership is the strongest predictor of milestone attainment, regardless of local socioeconomic conditions, ideological and political orientations of residents, or other climate-related initiatives within the state. This finding supports the general effectiveness of ICLEI’s network organizational model and its outreach and education efforts. However, member cities facing more “climate stress”, including higher levels of hazardous air pollutants (HAP’s) and greater automobile use among residents are making slower progress. The findings yield insight into the conditions under which cities engaged in climate planning are more likely to succeed in reducing local greenhouse gas emissions-relevant information for planners, community stakeholders and administrators of organizations like ICLEI.

A New Solution for the Dispersive Element in Astronomical Spectrographs
Harland W. Epps,Judith G. Cohen,J. Christopher Clemens
Physics , 2009, DOI: 10.1086/650547
Abstract: We present a new solution for the dispersive element in astronomical spectrographs, which in many cases can provide an upgrade path to enhance the spectral resolution of existing moderate-resolution reflection-grating spectrographs. We demonstrate that in the case of LRIS-R at the Keck 1 Telescope a spectral resolution of 18,000 can be achieved with reasonable throughput under good seeing conditions.
Rapid Diagnosis of Malaria
Clinton K. Murray,Jason W. Bennett
Interdisciplinary Perspectives on Infectious Diseases , 2009, DOI: 10.1155/2009/415953
Abstract: Malaria's global impact is expansive and includes the extremes of the healthcare system ranging from international travelers returning to nonendemic regions with tertiary referral medical care to residents in hyperendemic regions without access to medical care. Implementation of prompt and accurate diagnosis is needed to curb the expanding global impact of malaria associated with ever-increasing antimalarial drug resistance. Traditionally, malaria is diagnosed using clinical criteria and/or light microscopy even though both strategies are clearly inadequate in many healthcare settings. Hand held immunochromatographic rapid diagnostic tests (RDTs) have been recognized as an ideal alternative method for diagnosing malaria. Numerous malaria RDTs have been developed and are widely available; however, an assortment of issues related to these products have become apparent. This review provides a summary of RDT including effectiveness and strategies to select the ideal RDT in varying healthcare settings.
An Experimental Study of AJAX Application Performance
Clinton W. Smullen III,Stephanie A. Smullen
Journal of Software , 2008, DOI: 10.4304/jsw.3.3.30-37
Abstract: An experimental study compared the performance of a real-life HTML application and an AJAX application that implemented the same user interface. A statistically significant number of trials were used to collect data on the performance of each when presented with the same tasks. Response size and service time performance measures were computed for the applications. AJAX provided significant performance increase in response size, thereby reducing bandwidth requirements. A typical user would see a performance increase in the response size of 55%. AJAX provided a mean service time improvement of approximately 16%. A typical user’s service time would improve by 21%.
A Hybrid Technique for the Periodicity Characterization of Genomic Sequence Data
Julien Epps
EURASIP Journal on Bioinformatics and Systems Biology , 2009, DOI: 10.1155/2009/924601
Abstract: The detection of structure within the DNA sequence has long captivated the interest of the research community. Among the various statistical characterizations of sequence data, one measure of structure within sequences is the degree of correlation or periodicity at various displacements along the sequence. Periodicity characterization of sequence data provides a compact and informative representation that has been used in many studies of structure within genomic sequences, including DNA sequence analysis [1], gene and exon detection [2], tandem repeat detection [3], and DNA sequence search and retrieval [4].To measure such periodicity, autocorrelation has been widely employed [1, 5–11]. Similarly, Fourier analysis and its variants have been used for periodicity characterization of sequences [4, 9, 12–24]. In some cases [25, 26], the Fourier transform of the autocorrelation sequence has also been computed, however using existing symbolic-numeric mappings such as binary indicator sequences [27], this transform can also be calculated without first determining the autocorrelation. Other recent promising approaches to periodicity characterization for biological sequences include the periodicity transform [28], the exactly periodic subspace decomposition [3], and maximum-likelihood statistical periodicity [29], however these techniques have yet to be adopted by biologists for the purposes of sequence structure characterization.Studies of structure within sequences, such as those referenced above, have tended to use either the autocorrelation or the Fourier transform, and to the author's knowledge, the limitations of each have not been compared in this context. In this paper, the limitations of both approaches are investigated using synthetic symbolic sequences, and caveats to their characterization of sequence data are discussed. A hybrid approach to periodicity characterization of symbolic sequence data is introduced, and its use is illustrated in a comparative manner on
Who Works Where:
Brad Epps
Hispanic Issues On Line , 2006,
Abstract:
A Hybrid Technique for the Periodicity Characterization of Genomic Sequence Data
Epps Julien
EURASIP Journal on Bioinformatics and Systems Biology , 2009,
Abstract: Many studies of biological sequence data have examined sequence structure in terms of periodicity, and various methods for measuring periodicity have been suggested for this purpose. This paper compares two such methods, autocorrelation and the Fourier transform, using synthetic periodic sequences, and explains the differences in periodicity estimates produced by each. A hybrid autocorrelationa€”integer period discrete Fourier transform is proposed that combines the advantages of both techniques. Collectively, this representation and a recently proposed variant on the discrete Fourier transform offer alternatives to the widely used autocorrelation for the periodicity characterization of sequence data. Finally, these methods are compared for various tetramers of interest in C. elegans chromosome I.
The SIDE dual VIS-NIR fiber fed spectrograph for the 10.4 m Gran Telescopio Canarias
O. Rabaza,H. W. Epps,M. Ubierna,J. Sanchez,M. Azzaro,F. Prada
Physics , 2008, DOI: 10.1117/12.787357
Abstract: SIDE (Super Ifu Deployable Experiment) is proposed as second-generation, common-user instrument for the GTC. It will be a low and intermediate resolution fiber fed spectrograph, highly efficient in multi-object and 3D spectroscopy. The low resolution part (R = 1500, 4000) is called Dual VIS-NIR because it will observe in the VIS and NIR bands (0.4 ~V 1.7 microns) simultaneously. Because of the large number of fibers, a set of ~10 identical spectrographs is needed, each with a mirror collimator, a dichroic and two refractive cameras. The cameras are optimized for 0.4 - 0.95 microns (VIS) and 0.95 - 1.7 microns (NIR) respectively.
A New Observational Upper Limit to the Low Redshift Ionizing Background Radiation
R. J. Weymann,S. N. Vogel,S. Veilleux,H. W. Epps
Physics , 2001, DOI: 10.1086/323205
Abstract: We report a new Fabry-Perot search for Halpha emission from the intergalactic cloud HI 1225+01 in an attempt to measure the low redshift ionizing background radiation. We set a new 2 sigma upper limit on Halpha emission of 8 mR (5 x 10^{-20} ergs cm^{-2} s^{-1} arcsec^{-2}). Conversion of this limit to limits on the strength of the ionizing background requires knowledge of the ratio of the projected to total surface area of this cloud, which is uncertain. We discuss the plausible range of this ratio, and within this range find that the strength of the ionizing backround is in the lower range of, but consistent with, previous observational and theoretical estimates.
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