614 research outputs found
In Silico Synchronization of Cellular Populations Through Expression Data Deconvolution
Cellular populations are typically heterogenous collections of cells at
different points in their respective cell cycles, each with a cell cycle time
that varies from individual to individual. As a result, true single-cell
behavior, particularly that which is cell-cycle--dependent, is often obscured
in population-level (averaged) measurements. We have developed a simple
deconvolution method that can be used to remove the effects of asynchronous
variability from population-level time-series data. In this paper, we summarize
some recent progress in the development and application of our approach, and
provide technical updates that result in increased biological fidelity. We also
explore several preliminary validation results and discuss several ongoing
applications that highlight the method's usefulness for estimating parameters
in differential equation models of single-cell gene regulation.Comment: accepted for the 48th ACM/IEEE Design Automation Conferenc
Improved Limits on Sterile Neutrino Dark Matter using Full-Sky Fermi Gamma-Ray Burst Monitor Data
A sterile neutrino of ~keV mass is a well motivated dark matter candidate.
Its decay generates an X-ray line that offers a unique target for X-ray
telescopes. For the first time, we use the Gamma-ray Burst Monitor (GBM)
onboard the Fermi Gamma-Ray Space Telescope to search for sterile neutrino
decay lines; our analysis covers the energy range 10-25 keV (sterile neutrino
mass 20-50 keV), which is inaccessible to X-ray and gamma-ray satellites such
as Chandra, Suzaku, XMM-Newton, and INTEGRAL. The extremely wide field of view
of the GBM enables a large fraction of the Milky Way dark matter halo to be
probed. After implementing careful data cuts, we obtain ~53 days of full sky
observational data. We observe an excess of photons towards the Galactic
Center, as expected from astrophysical emission. We search for sterile neutrino
decay lines in the energy spectrum, and find no significant signal. From this,
we obtain upper limits on the sterile neutrino mixing angle as a function of
mass. In the sterile neutrino mass range 25-40 keV, we improve upon previous
upper limits by approximately an order of magnitude. Better understanding of
detector and astrophysical backgrounds, as well as detector response, will
further improve the sensitivity of a search with the GBM.Comment: 16 pages, 11 figures, references added, discussion expanded, some
typos fixed, matches the published versio
Unresolved Unidentified Source Contribution to the Gamma-ray Background
The large majority of EGRET point sources remain without an identified
low-energy counterpart, and a large fraction of these sources are most likely
extragalactic. Whatever the nature of the extragalactic EGRET unidentified
sources, faint unresolved objects of the same class must have a contribution to
the diffuse extragalactic gamma-ray background (EGRB). Understanding this
component of the EGRB, along with other guaranteed contributions from known
sources, is essential if we are to use this emission to constrain exotic
high-energy physics. Here, we follow an empirical approach to estimate whether
a potential contribution of unidentified sources to the EGRB is likely to be
important, and we find that it is. Additionally, we show how upcoming GLAST
observations of EGRET unidentified sources, as well as of their fainter
counterparts, can be combined with GLAST observations of the Galactic and
extragalactic diffuse backgrounds to shed light on the nature of the EGRET
unidentified sources even without any positional association of such sources
with low-energy counterparts.Comment: 11 pages, 5 figures, submitted to Ap
An Interview on Leadership with Al Carey, CEO, PepsiCo Beverages
Paul T. Barrett, PhD, CPA, is dean and professor of business for the College of Business and Economics, Longwood University, Farmville, VA 23909.
James C. Haug, DBA, is associate professor of management, Longwood University, College of Business and Economics, Farmville, VA 23909.
John N. Gaskins, PhD, currently serves as associate professor of marketing and retailing, Longwood University, College of Business and Economics, Farmville, VA 23909
Job satisfaction for campus recreation professionals within NIRSA institutions
An international investigation was conducted to determine the overall job satisfaction of college campus recreation employees who are members of the National Intramural Recreational Sports Association (NIRSA). Demographic information was gathered to provide statistical analysis based on (a) region; (b) size of school; (c) private versus public; (d) four-year versus two-year schools; (e) rural, suburban, and urban location; (f) years in the profession; and (g) reporting structure. The following work related areas were examined to determine if NIRSA members were satisfied with their job environment: (a) personal/individual satisfaction, (b) staffing and organizational structure, (c) financial support, (d) salary and professional development, (e) department and individual expectations, (f) campus recreation facilities, and (g) campus collaboration and communication. The study found that overall the respondents indicated they were satisfied with their job situation/ environment with greater satisfaction being shown by those with loftier job titles when compared with those with lesser job titles. Differences in job satisfaction were noted in terms of (a) supervisor’s expectations of them, salary, and hours worked (based on amount of experience); (b) salary (based on title held); (c) budget allocation (based on reporting structure); and (d) a desire to leave their present position/ job (in terms of job title held, experience/length of service and reporting structure)
New Sensitivity to Solar WIMP Annihilation using Low-Energy Neutrinos
Dark matter particles captured by the Sun through scattering may annihilate
and produce neutrinos, which escape. Current searches are for the few
high-energy neutrinos produced in the prompt decays of some final states. We
show that interactions in the solar medium lead to a large number of pions for
nearly all final states. Positive pions and muons decay at rest, producing
low-energy neutrinos with known spectra, including nuebar through neutrino
mixing. We demonstrate that Super-Kamiokande can thereby provide a new probe of
the spin-dependent WIMP-proton cross section. Compared to other methods, the
sensitivity is competitive and the uncertainties are complementary.Comment: 5 pages, 4 figure
Selected Risk Management Policies, Practices, and Procedures for Intramural Activities at NIRSA Institutions
A survey of all National Intramural-Recreational Sports Association (NIRSA) campus recreation directors was conducted to determine the risk management policies, practices, and procedures relating to intramural activities and recreational sports at colleges and universities throughout North America. The survey instrument, in its final form, addressed practices, policies, and procedures of campus recreation directors through 44 questions relating to the following areas: (a) documentation, (b) medical factors, (c) rules and regulations, (d) physical supervision, (e) sportsmanship rating systems, (f) restrictive policies, (g) safety devices, (h) officials-tests-qualifications, and (i) background experiences and training of the respondents. Selected data are presented in terms of (a) the size of institutions (small, medium, and large), (b) location of the institution (rural, urban, and suburban), and (c) whether public or privately supported
Club Sport Legal Liability Practices at NIRSA Institutions
Current legal practices in collegiate club sport programs were studied. A 23-item questionnaire consisting primarily of close-ended questions was mailed to 563 campus recreation directors representing all six National Intramural-Recreational Sports Association (NIRSA) regions. Data obtained showed that mean club sport budgets ranged from 135,657 in Region 6, with an overall mean of $69,138 across all regions. Signing a waiver before participating was required by 91 % of the directors. Lack of consistency in waiver language and font size was reported. Only 9% of campus recreation directors always require that an institutional employee travel with a club sport team. The most frequent modes of approved travel for club sport participants were students driving personal cars (94%), renting vans from outside vendors (95%), and the use of private transportation such as a chartered bus (70%). Paid coaches were used by 15% of the directors
Factors Affecting Risk Management of Indoor Campus Recreation Facilities
Factors affecting risk management of indoor campus recreation facilities were studied. Campus recreation directors of 4-year colleges/universities in North America who held memberships in the National Intramural-Recreational Sports Association (NIRSA) responded to a paper survey consisting of 32 dichotomous yes/no and closeended multiple-choice questions. Questions addressed staff certification requirements, use of waivers, number of automatic external defibrillators (AEDs) in the facility, communication and security devices, health screening of participants, and in-person supervision of the facility. Results showed that facilities are open to participants extensively throughout the 7-day week, thus requiring directors to ensure their risk management procedures are up to date—most notably staff members’ CPR and first aid certification, as well as AED training
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