406 research outputs found
Factors affecting retention of first-time, full-time freshmen students at higher education institutions within the Appalachian College Association
This study examined factors that may affect the retention of first-time, full-time college freshmen to sophomore year. Institutions in the Appalachian College Association (ACA) were invited to participate, and nine of the 35 member schools provided data. The research questions were (1) Is there a relationship between retention for studentsâ sophomore year and any of the following and (2) Based on any relationships identified in RQ 1, are there two or more variables that predict retention status for students? The data set contained 7,198 student records. The independent variables included: High school GPA, cumulative college GPA at the end of the freshman year, ACT score, gender, ethnicity, and residency status. The dependent variable was retention to sophomore year. Research question 1 used correlation analysis to establish relationships between the independent variables and retention. Point-biserial correlation analysis was performed for the three scale independent variables, ACT score, high school GPA, and cumulative college GPA. Pearsonâs chi-square was performed for the 3 nominal independent variables, gender, residency status, and ethnicity. The correlation analysis showed that 5 of the 6 variables had statistical significance with retention. Research question 2 used regression analysis to examine the independent variablesâ ability to predict retention to sophomore year. Cumulative college GPA and residency status showed the strongest ability to predict retention to sophomore year. Results from this study may encourage colleges and universities to begin or promote programs designed to assist students with maintaining a favorable GPA, such as study skills sessions or active learning environments. Information contained here may also lead to development of initiatives designed to increase social integration for students. These initiatives may include new programs or better scheduling of current offerings. Further research areas include using this methodology on other campuses, as well as developing a qualitative or mixed methods study to use at a single campus. Of the schools in the ACA, there may be interest in comparing schools considered more conservative with those considered more liberal. Finally, predictive analytics may be employed to examine other variables common among students who retain for sophomore year
An Ab Initio Study of the Mono- and Difluorides of Krypton
Results from ab initio calculations at the CCSD(T) level of theory are presented for krypton monofluoride (KrF), krypton monofluoride cation (KrF+), linear, ground-state krypton difluoride (KrF2), the triplet state of krypton difluoride, and the kryptonâfluorine van der Waals complex (KrâF2). These are the first calculations demonstrating that KrF is a bound molecule, in agreement with experimental observation. When corrected for basis-set superposition error, the calculated potential displays quantitative agreement with the attractive wall of the experimentally measured potential curve. Results are also presented for KrF+ and linear KrF2 which yield accurate values for their dissociation energies. The triplet state of KrF2 is found to have a minimum energy below that of separated atoms, and its structure is bent, with a small FâKrâF bond angle (71 deg). The van der Waals complex, KrâF2, appears to consist of an unperturbed F2 molecule attached to a krypton atom in the expected T-shaped structure
In-situ radio frequency identification (RFID) moisture meter
Title from PDF of title page, viewed on December 15, 2011Thesis advisor: Walter Daniel LeĂłn-SalasVitaIncludes bibliographic references (p. 61-62)Thesis (M.A.)--School of Computing and Engineering. University of Missouri--Kansas City, 2011An in-situ moisture meter, utilizing a Radio Frequency Identification (RFID) to detect
hidden moisture in walls is studied. Both commercial and household building moisture problems
call for a better way to measure moisture within the building envelope. The presence of moisture
within the insulating material of the building walls can attribute to the possibility of mold
growth. Simple resistor divider type moisture meters are easily realizable but do not always
provide the best methodology for detecting moisture levels accurately. An embeddable and
unobtrusive means to detect moisture within the wall cavity is studied. The methodology used
for detection is an improved type of resistive probe utilizing an integrating amplifier to determine
moisture content in typical celluose insulation. To compliment the resistive measurement, a
humidity sensor has been added along with a built-in temperature sensor embedded in the
MSP430 microcontroller.Introduction -- Mold and moisture -- Moisture circuits -- Integrator moisture meter -- Experiment -- Conclusion -- Appendix A. Moisture meter schematic -- Appendix B. Microcontroller program -- Appendix C. Costs -- Appendix D. Power consumptio
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Genetic transformation of the frog-killing chytrid fungus Batrachochytrium dendrobatidis
Batrachochytrium dendrobatidis (Bd), a causative agent of chytridiomycosis, is decimating amphibian populations around the world. Bd belongs to the chytrid lineage, a group of early-diverging fungi that are widely used to study fungal evolution. Like all chytrids, Bd develops from a motile form into a sessile, growth form, a transition that involves drastic changes in its cytoskeletal architecture. Efforts to study Bd cell biology, development, and pathogenicity have been limited by the lack of genetic tools with which to test hypotheses about underlying molecular mechanisms. Here, we report the development of a transient genetic transformation system for Bd. We used electroporation to deliver exogenous DNA into Bd cells and detected transgene expression for up to three generations under both heterologous and native promoters. We also adapted the transformation protocol for selection using an antibiotic resistance marker. Finally, we used this system to express fluorescent protein fusions and, as a proof of concept, expressed a genetically encoded probe for the actin cytoskeleton. Using live-cell imaging, we visualized the distribution and dynamics of polymerized actin at each stage of the Bd life cycle, as well as during key developmental transitions. This transformation system enables direct testing of key hypotheses regarding mechanisms of Bd pathogenesis. This technology also paves the way for answering fundamental questions of chytrid cell, developmental, and evolutionary biology
Classical Swine Fever Surveillance in Feral Swine
Diseases such as classical swine fever (CSF) and foot-and-mouth disease have been eradicated in the United States, but possible reintroductions merit the development of an enhanced surveillance system. Important foreign animal or transboundary diseases like these pose a significant risk to the health of wildlife and livestock in the United States. Wildlife Services (WS) performs surveillance in targeted feral swine (Sus scrofa) populations as part of a comprehensive United States Department of Agriculture, Animal and Plant Health Inspection Service effort to demonstrate disease-free status in our nation\u27s livestock and wildlife. Surveillance is based on risk assessments which identify high risk states and the vicinity of feral swine to transitional or commercial swine production facilities. During 2007 and 2008, WS sampled and tested (n = 3661) feral swine. CSF was not detected in feral swine in the United States through this surveillance effort
Detection and Characterization of a Distinct Bornavirus Lineage from Healthy Canada Geese (\u3ci\u3eBranta canadensis\u3c/i\u3e)
Avian bornaviruses (ABV), identified in 2008, infect captive parrots and macaws worldwide. The natural reservoirs of these viruses are unknown. Reverse transcription-PCR (RT-PCR) was used to screen oropharyngeal/ cloacal swab and brain samples from wild Canada geese (Branta canadensis) for ABV. Approximately 2.9% of swab samples were positive for bornavirus sequences. Fifty-two percent of brain samples from 2 urban flocks also tested positive, and brain isolates were cultured in duck embryo fibroblasts. Phylogenetic analyses placed goose isolates in an independent cluster, and more notably, important regulatory sequences present in Borna disease virus but lacking in psittacine ABVs were present in goose isolates
Testing Consumer Rationality using Perfect Graphs and Oriented Discs
Given a consumer data-set, the axioms of revealed preference proffer a binary
test for rational behaviour. A natural (non-binary) measure of the degree of
rationality exhibited by the consumer is the minimum number of data points
whose removal induces a rationalisable data-set.We study the computational
complexity of the resultant consumer rationality problem in this paper. This
problem is, in the worst case, equivalent (in terms of approximation) to the
directed feedback vertex set problem. Our main result is to obtain an exact
threshold on the number of commodities that separates easy cases and hard
cases. Specifically, for two-commodity markets the consumer rationality problem
is polynomial time solvable; we prove this via a reduction to the vertex cover
problem on perfect graphs. For three-commodity markets, however, the problem is
NP-complete; we prove thisusing a reduction from planar 3-SAT that is based
upon oriented-disc drawings
An allele of IKZF1 (Ikaros) conferring susceptibility to childhood acute lymphoblastic leukemia protects against type 1 diabetes.
OBJECTIVE: IKZF1 encoding Ikaros, an essential regulator of lymphopoiesis and immune homeostasis, has been implicated in the development of childhood acute lymphoblastic leukemia (C-ALL). Because recent genome-wide association (GWA) studies have linked a region of the 3'-UTR of IKZF1 with C-ALL susceptibility, we tested whether IKZF1 is associated with the autoimmune disease type 1 diabetes. RESEARCH DESIGN AND METHODS: rs10272724 (T>C) near IKZF1 at 7p12 was genotyped in 8,333 individuals with type 1 diabetes, 9,947 control subjects, and 3,997 families of European ancestry. Association was tested using logistic regression in the case-control data and by the transmission disequilibrium test in the families. Expression data for IKZF1 by rs10272724 genotype were obtained using quantitative PCR of mRNA/cDNA generated from peripheral blood mononuclear cells from 88 individuals, whereas expression data for five other neighboring genes were obtained from the online Genevar dataset. RESULTS: The minor allele of rs10272724 (C) was found to be protective from type 1 diabetes (odds ratio 0.87 [95% CI 0.83-0.91]; P = 1.1 Ă 10(-11)). rs10272724 was not correlated with levels of two transcripts of IKZF1 in peripheral blood mononuclear cells. CONCLUSIONS: The major susceptibility genotype for C-ALL confers protection from type 1 diabetes. Our finding strengthens the link between autoimmunity and lymphoid cancers. Further investigation is warranted for the genetic effect marked by rs10272724, its impact on IKZF1, and the role of Ikaros and other family members, Ailios (IKZF3) and Eos (IKZF4), in autoimmunity
Demographic and Spatiotemporal Patterns of Avian Influenza Infection at the Continental Scale, and in Relation to Annual Life Cycle of a Migratory Host
Since the spread of highly pathogenic avian influenza (HPAI) H5N1 in the eastern hemisphere, numerous surveillance programs and studies have been undertaken to detect the occurrence, distribution, or spread of avian influenza viruses (AIV) in wild bird populations worldwide. To identify demographic determinants and spatiotemporal patterns of AIV infection in long distance migratory waterfowl in North America, we fitted generalized linear models with binominal distribution to analyze results from 13,574 blue-winged teal (Anas discors, BWTE) sampled in 2007 to 2010 year round during AIV surveillance programs in Canada and the United States. Our analyses revealed that during late summer staging (July-August) and fall migration (September-October), hatch year (HY) birds were more likely to be infected than after hatch year (AHY) birds, however there was no difference between age categories for the remainder of the year (winter, spring migration, and breeding period), likely due to maturing immune systems and newly acquired immunity of HY birds. Probability of infection increased non-linearly with latitude, and was highest in late summer prior to fall migration when densities of birds and the proportion of susceptible HY birds in the population are highest. Birds in the Central and Mississippi flyways were more likely to be infected compared to those in the Atlantic flyway. Seasonal cycles and spatial variation of AIV infection were largely driven by the dynamics of AIV infection in HY birds, which had more prominent cycles and spatial variation in infection compared to AHY birds. Our results demonstrate demographic as well as seasonal, latitudinal and flyway trends across Canada and the US, while illustrating the importance of migratory host life cycle and age in driving cyclical patterns of prevalence
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