460 research outputs found
Modeling Genetic Networks from Clonal Analysis
In this report a systematic approach is used to determine the approximate
genetic network and robust dependencies underlying differentiation. The data
considered is in the form of a binary matrix and represent the expression of
the nine genes across the ninety-nine colonies. The report is divided into two
parts: the first part identifies significant pair-wise dependencies from the
given binary matrix using linear correlation and mutual information. A new
method is proposed to determine statistically significant dependencies
estimated using the mutual information measure. In the second, a Bayesian
approach is used to obtain an approximate description (equivalence class) of
network structures. The robustness of linear correlation, mutual information
and the equivalence class of networks is investigated with perturbation and
decreasing colony number. Perturbation of the data was achieved by generating
bootstrap realizations. The results are refined with biological knowledge. It
was found that certain dependencies in the network are immune to perturbation
and decreasing colony number and may represent robust features, inherent in the
differentiation program of osteoblast progenitor cells. The methods to be
discussed are generic in nature and not restricted to the experimental paradigm
addressed in this study.Comment: 59 pahes, 11 figures, 3 table
Ecological niche modeling and differentiation of populations of *Triatoma brasiliensis* Neiva, 1911, the most important Chagas disease vector in northeastern Brazil (Hemiptera, Reduviidae, Triatominae)
Am. J. Trop. Med. Hyg., 67(5), 2002, pp. 516â520
Copyright Š 2002 by The American Society of TropicalMedicine and Hygiene
516
http://www.ajtmh.org/cgi/reprint/67/5/516Ecologic niche modeling has allowed numerous advances in understanding the geographic ecology of
species, including distributionalpredictions, distributionalchange and invasion, and assessment of ecologic differences.
We used this toolto characterize ecologic differentiation of Triatoma brasiliensis populations, the most important
Chagasâ disease vector in northeastern Brazil. The speciesâ ecologic niche was modeled based on data from the Fundação
Nacionalde SaĂşde of Brazil(1997â1999) with the Genetic Algorithm for Rule-Set Prediction (GARP). This method
involves a machine-learning approach to detecting associations between occurrence points and ecologic characteristics
of regions. Four independent âecologic niche modelsâ were developed and used to test for ecologic differences among
T. brasiliensis populations. These models confirmed four ecologically distinct and differentiated populations, and
allowed characterization of dimensions of niche differentiation. Patterns of ecologic similarity matched patterns of
molecular differentiation, suggesting that T. brasiliensis is a complex of distinct populations at various points in the
process of speciation
Geographic Distribution of Chagas Disease Vectors in Brazil Based on Ecological Niche Modeling
Although Brazil was declared free from Chagas disease transmission by the domestic vector Triatoma infestans, human acute cases are still being registered based on transmission by native triatomine species. For a better understanding of transmission risk, the geographic distribution of Brazilian triatomines was analyzed. Sixteen out of 62 Brazilian species that both occur in >20 municipalities and present synanthropic tendencies were modeled based on their ecological niches. Panstrongylus geniculatus and P. megistus showed broad ecological ranges, but most of the species sort out by the biome in which they are distributed: Rhodnius pictipes and R. robustus in the Amazon; R. neglectus, Triatoma sordida, and T. costalimai in the Cerrado; R. nasutus, P. lutzi, T. brasiliensis, T. pseudomaculata, T. melanocephala, and T. petrocchiae in the Caatinga; T. rubrovaria in the southern pampas; T. tibiamaculata and T. vitticeps in the Atlantic Forest. Although most occurrences were recorded in open areas (Cerrado and Caatinga), our results show that all environmental conditions in the country are favorable to one or more of the species analyzed, such that almost nowhere is Chagas transmission risk negligible
Clergy Perceptions of Denominational, Doctrine and Seminary School Support for Health and Wellness in Churches
Background: Churches are a viable community partner for reaching large populations for health promotion interventions. Despite their usefulness, little is known about the institutional capacity or beliefs of churches toward health. The purpose of this qualitative study was to examine how a churchesâ doctrine, parent organization (e.g. conference/diocese), and leader training (e.g. seminary school) perceive and support health-related issues. Design & Methods: Clergy (n=24) from multiple denominations participated in a semi-structured interview. The interviewer asked questions about the doctrine/philosophy of their church on health, parent organization support for health, and education and training on health. Interviews were recorded, transcribed and coded. Results: Clergy reported that stewardship and holistic views on health were a part of their churchesâ doctrine. Health insurance programs and clergy wellness initiatives were the most common form of health-related support from parent organizations. The majority of clergy reported minimal or no instruction on health during their education/training, and desired instruction on self-care in seminary school. These results indicate there are a number of institutional influences on health and wellness within churches. Conclusions: Future programs could include policy and environment level initiatives to address clergy health, and the development of culturally tailored intervention concurrent with church doctrine
Long distance decoy state quantum key distribution in optical fiber
The theoretical existence of photon-number-splitting attacks creates a
security loophole for most quantum key distribution (QKD) demonstrations that
use a highly attenuated laser source. Using ultra-low-noise, high-efficiency
transition-edge sensor photodetectors, we have implemented the first version of
a decoy-state protocol that incorporates finite statistics without the use of
Gaussian approximations in a one-way QKD system, enabling the creation of
secure keys immune to photon-number-splitting attacks and highly resistant to
Trojan horse attacks over 107 km of optical fiber.Comment: 4 pages, 3 figure
Ethanol plant location and intensification vs. extensification of corn cropping in Kansas
This is the author final draft. Copyright 2014 Elsevier.Farmers' cropping decisions are a product of a complex mix of socio-economic, cultural, and natural environments in which factors operating at a number of different spatial scales affect how farmers ultimately decide to use their land in any given year or over a set of years. Some environmentalists are concerned that increased demand for corn driven by ethanol production is leading to conversion of non-cropland into corn production (which we label as âextensificationâ). Ethanol industry advocates counter that more than enough corn supply comes from crop switching to corn and increased yields (which we label as âintensificationâ). In this study, we determine whether either response to corn demand â intensification or extensification â is supported. This is determined through an analysis of land-use/land-cover (LULC) data that covers the state of Kansas and a measure of a corn demand shifter related to ethanol production â distance to the closest ethanol plant â between 2007 and 2009
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