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Search Results: 1 - 10 of 308419 matches for " William J. Federspiel "
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On Laminar Flow in Microfabricated Channels with Partial Semi-Circular Profiles  [PDF]
William J. Federspiel, Isabella Valenti
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.21003
Abstract: Soft and hard micromachining techniques used to develop microfluidic devices can yield microchannels of many different cross-sectional profiles. For semi-circular microchannels, these techniques often produce only partialsemicircular (PSC) cross-sections. This study investigated fully developed laminar flow in PSC microchannels as a function of a circularity index, κ, defined as the ratio of the radiuses along the curved and flat surfaces of the PSC profile. A correction factor, K, to the Hagen-Poiseuille relation was determined and was well-fitted by the power-law relationship K=5.299/κ2.56. Actual correction factors were compared to estimates based on several hydraulic models for flow in microchannels of arbitrary cross-section, as well as the half-ellipsoid cross-section. The level of wall shear stress, when normalized by the pressure drop per unit length, increased approximately linearly with increase in the circularity index, κ.
Investigating Cytokine Binding Using a Previously Reported TNF-Specific Aptamer  [PDF]
James D. Fisher, Morgan V. DiLeo, William J. Federspiel
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.23019
Abstract: Cytokines are of chief importance in the pathophysiology of sepsis and other systemic inflammatory response syndromes. We are designing and testing an extracorporeal cytokine adsorption device (CAD) that can remove cytokines via adsorption on biocompatible, microporous beads. The goal of this study was to determine whether a previously reported TNF binding DNA aptamer, 5’-GCGGCCGATA AGGTCTTTCC AAGCGAACGA ATTGAACCGC-3’, could be immobilized our hemoadsorption polymer surface to increase the removal rate of TNF. A reservoir consisting of horse serum spiked with a known concentration of TNF was perfused through our CAD packed with aptamer modified or unmodified (control) polymer beads. The binding affinity of the TNF aptamer was characterized using an enzyme-linked oligonucleotide assay (ELONA). As a positive control a well-established DNA aptamer that binds PDGF BB was also subjected to the same ELONA to validate the assay. TNF capture using the CAD showed no TNF removal over four hours for both the aptamer modified and unmodified control beads. Additionally, the results of the ELONA showed no binding of TNF to the reported aptamer; however the PDGF BB aptamer did bind PDGF BB. Based on these results we are able to conclude that the reported TNF specific aptamer does not bind TNF. These results will be of importance to other studies exploring aptamers for specific binding of TNF.
Do Leveraged ETFs Increase Volatility  [PDF]
William J. Trainor
Technology and Investment (TI) , 2010, DOI: 10.4236/ti.2010.13026
Abstract: The 2008 financial crisis has produced volatility levels not seen since the 1987 stock market crash more than 20 years ago. During that time, the culprit was thought to be index futures and program trading. This time, leveraged ETFs and their rebalancing trades have been singled out by some to explain both the spike in volatility and the appearance of large price swings at the end of the trading day. This study examines the merit of these accusations and whether the increase in volatility and end of the day price momentum is indeed linked to leveraged ETFs and their rebalancing trades. For the S&P 500, the relationship appears to be a spurious coincidence.
Calculating First Moments and Confidence Intervals for Generalized Stochastic Dividend Discount Models  [PDF]
William J. Hurley
Journal of Mathematical Finance (JMF) , 2013, DOI: 10.4236/jmf.2013.32027
Abstract:

This paper presents models of equity valuation where future dividends are assumed to follow a generalized Bernoulli process consistent with the actual dividend payout behavior of many firms. This uncertain dividend stream induces a probability distribution of present value. We show how to calculate the first moment of this distribution using functional equations. As well, we demonstrate how to calculate a confidence interval using Monte Carlosimulation. This first moment and interval allows an analyst to determine whether a stock is overor under-valued.

On Some Numbers Related to the Erdös-Szekeres Theorem  [PDF]
Mark J. Nielsen, William Webb
Open Journal of Discrete Mathematics (OJDM) , 2013, DOI: 10.4236/ojdm.2013.33030
Abstract:

A crossing family of segments is a collection of segments each pair of which crosses. Given positive integers j and k,a(j,k) grid is the union of two pairwise-disjoint collections of segments (with j and k members, respectively) such that each segment in the first collection crosses all members of the other. Let c(k) be the least integer such that any planar set of c(k) points in general position generates a crossing family of k segments. Also let #(j,k) be the least integer such that any planar set of #(j,k) points in general position generates a (j,k)-grid. We establish here the facts 9≤c(3)≤16 and #(1,2)=8.


Focussing in on H_0
G. A. Tammann,M. Federspiel
Physics , 1996,
Abstract: Six independent methods yield a Virgo cluster modulus of (m-M)=31.66+/- 0.08. This inserted into the Hubble diagram of clusters, whose relative distances to the Virgo cluster are known, gives H_0=54+/-4. The result is independent of any observed or inferred velocity of the Virgo cluster and holds out 10 000 km/s. An analogous use of the Fornax cluster is not yet possible because of its unknown structure in space and its poorly understood distance relative to other clusters. Field galaxies, corrected for Malmquist bias, give H_0=53+/-3. The results of purely physical distance determinations cluster around H_0=55+/-10. These results may be compared with the high-weight determination of H_0=58.5+/-3 from Cepheid-calibrated SNe Ia and their Hubble diagram out to 30 000 km/s (Saha 1996). The agreement of the independent methods suggests that the external error of an adopted value of H_0=58 is equal or less than 13%.
Mathematical Model for Radial Expansion and Conflation of Intratumoral Infectious Centers Predicts Curative Oncolytic Virotherapy Parameters
Kent Bailey, Amber Kirk, Shruthi Naik, Rebecca Nace, Michael B. Steele, Lukkana Suksanpaisan, Xing Li, Mark J. Federspiel, Kah-Whye Peng, David Kirk, Stephen J. Russell
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0073759
Abstract: Simple, inductive mathematical models of oncolytic virotherapy are needed to guide protocol design and improve treatment outcomes. Analysis of plasmacytomas regressing after a single intravenous dose of oncolytic vesicular stomatitis virus in myeloma animal models revealed that intratumoral virus spread was spatially constrained, occurring almost exclusively through radial expansion of randomly distributed infectious centers. From these experimental observations we developed a simple model to calculate the probability of survival for any cell within a treated tumor. The model predicted that small changes to the density of initially infected cells or to the average maximum radius of infected centers would have a major impact on treatment outcome, and this was confirmed experimentally. The new model provides a useful and flexible tool for virotherapy protocol optimization.
Cortico-Cortical White Matter Motor Pathway Microstructure Is Related to Psychomotor Retardation in Major Depressive Disorder
Tobias Bracht, Andrea Federspiel, Susanne Schnell, Helge Horn, Oliver H?fle, Roland Wiest, Thomas Dierks, Werner Strik, Thomas J. Müller, Sebastian Walther
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0052238
Abstract: Alterations of brain structure and function have been associated with psychomotor retardation in major depressive disorder (MDD). However, the association of motor behaviour and white matter integrity of motor pathways in MDD is unclear. The aim of the present study was to first investigate structural connectivity of white matter motor pathways in MDD. Second, we explore the relation of objectively measured motor activity and white matter integrity of motor pathways in MDD. Therefore, 21 patients with MDD and 21 healthy controls matched for age, gender, education and body mass index underwent diffusion tensor imaging and 24 hour actigraphy (measure of the activity level) the same day. Applying a probabilistic fibre tracking approach we extracted connection pathways between the dorsolateral prefrontal cortex (dlPFC), the rostral anterior cingulate cortex (rACC), the pre-supplementary motor area (pre-SMA), the SMA-proper, the primary motor cortex (M1), the caudate nucleus, the putamen, the pallidum and the thalamus. Patients had lower activity levels and demonstrated increased mean diffusivity (MD) in pathways linking left pre-SMA and SMA-proper, and right SMA-proper and M1. Exploratory analyses point to a positive association of activity level and mean-fractional anisotropy in the right rACC-pre-SMA connection in MDD. Only MDD patients with low activity levels had a negative linear association of activity level and mean-MD in the left dlPFC-pre-SMA connection. Our results point to structural alterations of cortico-cortical white matter motor pathways in MDD. Altered white matter organisation of rACC-pre-SMA and dlPFC-pre-SMA pathways may contribute to movement initiation in MDD.
Using Visual Arts to Encourage Children with Autism Spectrum Disorder to Communicate Their Feelings and Emotions  [PDF]
Alicia Round, William J. Baker, Christopher Rayner
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.510009
Abstract:
Children with Autism Spectrum Disorder (ASD) often experience difficulties in identifying their emotions and the emotional states of others, additionally, they also often experience challenges in verbal communication. Together, these characteristics can lead to compromised social and emotional well being and mental health issues. However, children with ASD often have relative strengths in visual processing, and such strengths have been integral to the success of visual supports and video-based interventions for a range of socially significant skills for children with ASD. This preference for visual processing may also rep-resent opportunities for children with ASD in identifying and expressing their emotions. There is a limited but promising body of literature that suggests visual Art therapy can be beneficial for individuals with ASD and provide opportuni-ties for them to develop flexibility, self-esteem, and social communicative behaviour [1]. This presentation reports a study exploring the potential of Art making to assist children with ASD to better communicate their feelings and emotions. Providing an outlet for self-expression may reduce the challenges people with Autism face and in doing so, improve the quality of life for them as well as their families. A qualitative descriptive case study was chosen for this study within the theoretical framework of Art as therapy. Two boys, aged seven and ten years, participated in five and six visual Art as therapy sessions (re-spectively). The sessions developed participants’ skills in Art making and ex-pressing emotion as rapport was built over the study period. A variety of rich data were collected during the study which included: questionnaires, interviews, video-recordings, observation notes and participant Art works. This presentation showcases the Art works of the participating boys, featuring a variety of mediums to communicate their thoughts, feelings, and emotions. A description of the visual Art as therapy experiences and the impacts upon students’ communication, social interaction, and self-esteem are discussed.
Financial Conflict Messages and Marital Satisfaction: The Mediating Role of Financial Communication Satisfaction  [PDF]
Samantha J. Shebib, William R. Cupach
Psychology (PSYCH) , 2018, DOI: 10.4236/psych.2018.91010
Abstract: Conflict over money is one of the most commonly cited topics of marital disagreements (Oggins, 2003). However, little empirical research has examined how marital couples communicate about financial issues, specifically, and how these financial communication messages contribute to, or detract from, marital satisfaction. Knowledge about how couples communicate regarding financial issues is of significance to conflict scholars because it would allow us to understand the potential detriments of certain financial conflict message patterns and how these patterns ultimately affect one’s marital satisfaction. Married individuals (not marital dyads) were recruited online to participate in an online survey about their financial communication patterns within his or her marriage. In the present study of 326 married individuals, we found that constructive financial conflict messages were positively associated with financial harmony, marital satisfaction, and financial communication satisfaction. Destructive financial conflict messages, the demand-withdraw financial conflict message pattern, and mutually avoiding financial conflict were each negatively associated with financial harmony, marital satisfaction, and financial communication satisfaction. In addition, financial communication satisfaction mediated the relationship between each of the financial conflict message patterns and marital satisfaction. The current study lays empirical groundwork for developing a theoretical framework for understanding marital interaction patterns and the effects these patterns have on marital satisfaction.
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