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Search Results: 1 - 10 of 469734 matches for " Matthew A. Maccani "
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miR-16 and miR-21 Expression in the Placenta Is Associated with Fetal Growth
Matthew A. Maccani,James F. Padbury,Carmen J. Marsit
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0021210
Abstract: Novel research has suggested that altered miRNA expression in the placenta is associated with adverse pregnancy outcomes and with potentially harmful xenobiotic exposures. We hypothesized that aberrant expression of miRNA in the placenta is associated with fetal growth, a measurable phenotype resulting from a number of intrauterine factors, and one which is significantly predictive of later life outcomes.
Placental 11-Beta Hydroxysteroid Dehydrogenase Methylation Is Associated with Newborn Growth and a Measure of Neurobehavioral Outcome
Carmen J. Marsit, Matthew A. Maccani, James F. Padbury, Barry M. Lester
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033794
Abstract: Background There is growing evidence that the intrauterine environment can impact the neurodevelopment of the fetus through alterations in the functional epigenome of the placenta. In the placenta, the HSD11B2 gene encoding the 11-beta hydroxysteroid dehydrogenase enzyme, which is responsible for the inactivation of maternal cortisol, is regulated by DNA methylation, and has been shown to be susceptible to stressors from the maternal environment. Methodology/Principal Findings We examined the association between DNA methylation of the HSD11B2 promoter region in the placenta of 185 healthy newborn infants and infant and maternal characteristics, as well as the association between this epigenetic variability and newborn neurobehavioral outcome assessed with the NICU Network Neurobehavioral Scales. Controlling for confounders, HSD11B2 methylation extent is greatest in infants with the lowest birthweights (P = 0.04), and this increasing methylation was associated with reduced scores of quality of movement (P = 0.04). Conclusions/Significance These results suggest that factors in the intrauterine environment which contribute to birth outcome may be associated with placental methylation of the HSD11B2 gene and that this epigenetic alteration is in turn associated with a prospectively predictive early neurobehavioral outcome, suggesting in some part a mechanism for the developmental origins of infant neurological health.
A Leader’s Perspective: Using Qualitative Methodology for Program Evaluation in a Rural Middle School  [PDF]
Matthew A. Birdwell
Open Journal of Leadership (OJL) , 2018, DOI: 10.4236/ojl.2018.71002
Abstract:
The purpose of this study was to analyze the male student population at West Texas Middle School in order to determine why the majority of male students at West Texas Middle School do not participate in the athletic program. This particular study was classified as both a case study and a program evaluation due to the nature of the study containing elements of both paradigms. The instruments that the researcher used to collect data were student questionnaires, structured interviews, formal observations, and attendance/academic data documents. A questionnaire was selected for data collection because of the possibility for collecting rich data straight from the student population. Structured group interviews were conducted in order to capture current and valid data from the coaching staff and the athletic director. Informal observations were conducted in order to gather rich data of interactions between coaches and students. Attendance and academic document data was collected to compare the effectiveness of athletic programs. Finally, semi structured interviews were utilized to gather opinions and perspectives of the coaches in regards to the athletic program. The findings from data analysis revealed that the male athletic department experienced low participation numbers due to a lack of student’s interest and a harmful climate created by the athletics director and coaching staff. The study revealed that the students were heavily involved in extracurricular activities. However, a small percentage of these students were involved in boy’s athletics. The athletic program lacked a clear vision with aligned goals. This, along with the toxic working environment, contributed to the toxic culture of the male athletic program.
Nonnegative Matrix Factorization with Zellner Penalty  [PDF]
Matthew A. Corsetti, Ernest Fokoué
Open Journal of Statistics (OJS) , 2015, DOI: 10.4236/ojs.2015.57077
Abstract:

Nonnegative matrix factorization (NMF) is a relatively new unsupervised learning algorithm that decomposes a nonnegative data matrix into a parts-based, lower dimensional, linear representation of the data. NMF has applications in image processing, text mining, recommendation systems and a variety of other fields. Since its inception, the NMF algorithm has been modified and explored by numerous authors. One such modification involves the addition of auxiliary constraints to the objective function of the factorization. The purpose of these auxiliary constraints is to impose task-specific penalties or restrictions on the objective function. Though many auxiliary constraints have been studied, none have made use of data-dependent penalties. In this paper, we propose Zellner nonnegative matrix factorization (ZNMF), which uses data-dependent auxiliary constraints. We assess the facial recognition performance of the ZNMF algorithm and several other well-known constrained NMF algorithms using the Cambridge ORL database.

Black-Scholes Option Pricing Model Modified to Admit a Miniscule Drift Can Reproduce the Volatility Smile  [PDF]
Matthew C. Modisett, James A. Powell
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.36093
Abstract: This paper develops a closed-form solution to an extended Black-Scholes (EBS) pricing formula which admits an implied drift parameter alongside the standard implied volatility. The market volatility smiles for vanilla call options on the S&P 500 index are recreated fitting the best volatility-drift combination in this new EBS. Using a likelihood ratio test, the implied drift parameter is seen to be quite significant in explaining volatility smiles. The implied drift parameter is sufficiently small to be undetectable via historical pricing analysis, suggesting that drift is best considered as an implied parameter rather than a historically-fit one. An overview of option-pricing models is provided as background.
Theta Rhythms Coordinate Hippocampal–Prefrontal Interactions in a Spatial Memory Task
Matthew W. Jones,Matthew A. Wilson
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0030402
Abstract: Decision-making requires the coordinated activity of diverse brain structures. For example, in maze-based tasks, the prefrontal cortex must integrate spatial information encoded in the hippocampus with mnemonic information concerning route and task rules in order to direct behavior appropriately. Using simultaneous tetrode recordings from CA1 of the rat hippocampus and medial prefrontal cortex, we show that correlated firing in the two structures is selectively enhanced during behavior that recruits spatial working memory, allowing the integration of hippocampal spatial information into a broader, decision-making network. The increased correlations are paralleled by enhanced coupling of the two structures in the 4- to 12-Hz theta-frequency range. Thus the coordination of theta rhythms may constitute a general mechanism through which the relative timing of disparate neural activities can be controlled, allowing specialized brain structures to both encode information independently and to interact selectively according to current behavioral demands.
Theta rhythms coordinate hippocampal-prefrontal interactions in a spatial memory task.
Jones Matthew W,Wilson Matthew A
PLOS Biology , 2005,
Abstract: Decision-making requires the coordinated activity of diverse brain structures. For example, in maze-based tasks, the prefrontal cortex must integrate spatial information encoded in the hippocampus with mnemonic information concerning route and task rules in order to direct behavior appropriately. Using simultaneous tetrode recordings from CA1 of the rat hippocampus and medial prefrontal cortex, we show that correlated firing in the two structures is selectively enhanced during behavior that recruits spatial working memory, allowing the integration of hippocampal spatial information into a broader, decision-making network. The increased correlations are paralleled by enhanced coupling of the two structures in the 4- to 12-Hz theta-frequency range. Thus the coordination of theta rhythms may constitute a general mechanism through which the relative timing of disparate neural activities can be controlled, allowing specialized brain structures to both encode information independently and to interact selectively according to current behavioral demands.
Theta Rhythms Coordinate Hippocampal–Prefrontal Interactions in a Spatial Memory Task
Matthew W Jones,Matthew A Wilson
PLOS Biology , 2005, DOI: 10.1371/journal.pbio.0030402
Abstract: Decision-making requires the coordinated activity of diverse brain structures. For example, in maze-based tasks, the prefrontal cortex must integrate spatial information encoded in the hippocampus with mnemonic information concerning route and task rules in order to direct behavior appropriately. Using simultaneous tetrode recordings from CA1 of the rat hippocampus and medial prefrontal cortex, we show that correlated firing in the two structures is selectively enhanced during behavior that recruits spatial working memory, allowing the integration of hippocampal spatial information into a broader, decision-making network. The increased correlations are paralleled by enhanced coupling of the two structures in the 4- to 12-Hz theta-frequency range. Thus the coordination of theta rhythms may constitute a general mechanism through which the relative timing of disparate neural activities can be controlled, allowing specialized brain structures to both encode information independently and to interact selectively according to current behavioral demands.
Comparison of Methods to Remediate Compacted Soils for Infiltration and Vegetative Establishment  [PDF]
Matthew A. Haynes, Richard A. McLaughlin, Joshua L. Heitman
Open Journal of Soil Science (OJSS) , 2013, DOI: 10.4236/ojss.2013.35027
Abstract:

The process of constructing roads and buildings usually involves the removal of topsoil and grading of the subsoil followed by a variety of activities using heavy equipment. This presents multiple challenges in attempts to establish vegetation on these areas: low nutrient soils with little organic matter, high bulk densities, and low infiltration rates. The goals of this preliminary study were to quantify the impacts of soil compaction remediation methods on infiltration, runoff water quality, and vegetation establishment. The objectives were to measure: 1) steady state infiltration rate (IR); 2) quantity and quality of storm water runoff; and 3) ground cover, biomass production, and rooting depth of vegetation during early establishment. We evaluated four treatments: a compacted soil (C), a compacted soil with core aeration (A), a compacted soil with deep (20 - 30 cm) tillage (DT), and a compacted soil with deep tillage and incorporated compost (CT). Sites 1 and 2 received C, A and DT treatments and Site 3 received only DT and CT treatments. At Site 1, runoff from natural rainfall events was collected in plastic tubs at the bottom of each 2 × 1 m plot, and samples were measured for volume and sediment. Infiltration rates were determined using a Cornell Sprinkle Infiltrometer at all three sites. At Site 1, the A treatment had a higher erosion rate during two of four rain events and higher runoff volume during three of four rain events, when compared to C and DT. However, the aerator was only able to penetrate 1 - 2 cm due to the compacted soil. Average event runoff ranged from 0 to 22% (0 - 9.3 mm), 10 to 60% (1.9 - 26.2 mm), and 0 to 3.5% (0 - 1.1 mm) of the total rainfall for C, A, and DT, respectively. There was no difference between C and A for vegetative biomass and IR, but both biomass and IR were greater in the DT plots. Treatment DT had an average IR of 15 cm·hr-1, compared to 0.16 and 0.21 cm·hr-1 for C and A, respectively. Roots were much more abundant at the 20 - 50 cm depths with DT. At Site 2, there were no significant differences in IR, with many values too low to be measured with the infiltrometer. Vegetative cover also did not differ between the three treatments due to poor (16% - 22% cover)

Whole-Genome Pathway Analysis on 132,497 Individuals Identifies Novel Gene-Sets Associated with Body Mass Index
Matthew A. Simonson, Matthew B. McQueen, Matthew C. Keller
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0078546
Abstract: Whole genome pathway analysis is a powerful tool for the exploration of the combined effects of gene-sets within biological pathways. This study applied Interval Based Enrichment Analysis (INRICH) to perform whole-genome pathway analysis of body-mass index (BMI). We used a discovery set composed of summary statistics from a meta-analysis of 123,865 subjects performed by the GIANT Consortium, and an independent sample of 8,632 subjects to assess replication of significant pathways. We examined SNPs within nominally significant pathways using linear mixed models to estimate their contribution to overall BMI heritability. Six pathways replicated as having significant enrichment for association after correcting for multiple testing, including the previously unknown relationships between BMI and the Reactome regulation of ornithine decarboxylase pathway, the KEGG lysosome pathway, and the Reactome stabilization of P53 pathway. Two non-overlapping sets of genes emerged from the six significant pathways. The clustering of shared genes based on previously identified protein-protein interactions listed in PubMed and OMIM supported the relatively independent biological effects of these two gene-sets. We estimate that the SNPs located in examined pathways explain ~20% of the heritability for BMI that is tagged by common SNPs (3.35% of the 16.93% total).
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