120 research outputs found
The Ghana Small Business Development Project
The Honors Program at the University of North Florida has established a bi-annual study abroad trip to Ghana, West Africa. The trip offers students the opportunity to gain an integrated perspective of the world outside the United States and other Western cultures. As a part of the May 2003 trip, several development projects were undertaken in cities throughout Ghana. The aim of the projects was both to contribute to the participating communities and to offer UNFstudents an opportunity in which they could apply the knowledge and skills learned in the classroom to real life experiences. In addition to community health and civil society projects, one student created and implemented the Ghana Small Business Development Project, a one-day workshop which focused on empowering two groups of women to become entrepreneurs.This paper is a brief review of the project’s specifications, after a discussion of the changing nature of development policy and practice over the last half of the twentieth century. The Ghana Small Business Development Project was designed to utilize a new perspective of development, often called bottom-up or participatory development, which has emerged in the aftermath of the failure of many development projects implemented during the in the second half of the twentieth century. The business development project aimed at using modern development theories to surmount past developmental shortcomings, thereby generating a means of income, creating employment, and raising the overall standard of living for a group of Ghanaian women
Radiative feedback from massive black holes in elliptical galaxies. AGN flaring and central starburst fueled by recycled gas
The importance of the radiative feedback from massive black holes at the
centers of elliptical galaxies is not in doubt, given the well established
relations among electromagnetic output, black hole mass and galaxy optical
luminosity. We show how this AGN radiative output affects the hot ISM of an
isolated elliptical galaxy with the aid of a high-resolution hydrodynamical
code, where the cooling and heating functions include photoionization plus
Compton heating. We find that radiative heating is a key factor in the
self-regulated coevolution of massive black holes and their host galaxies and
that 1) the mass accumulated by the central black hole is limited by feedback
to the range observed today, and 2) relaxation instabilities occur so that duty
cycles are small enough (~0.03) to account for the very small fraction of
massive ellipticals observed to be in the "on" -QSO- phase, when the accretion
luminosity approaches the Eddington luminosity. The duty cycle of the hot
bubbles inflated at the galaxy center during major accretion episodes is of the
order of 0.1-0.4. Major accretion episodes caused by cooling flows in the
recycled gas produced by normal stellar evolution trigger nuclear starbursts
coincident with AGN flaring. During such episodes the central sources are often
obscured; but overall, in the bursting phase (1<z<3), the duty cycle of the
black hole in its "on" phase is of the order of percents and it is unobscured
approximately one-third of the time. Mechanical energy output from
non-relativistic gas winds integrates to 2.3 10^{59} erg, with most of it
caused by broadline AGN outflows. [abridged]Comment: ApJ resubmitted. 48 pages, 14 figures (some of them new, bitmapped,
low resolution). New references added, typos correcte
The Fifth Data Release of the Sloan Digital Sky Survey
This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky
Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and
represents the completion of the SDSS-I project (whose successor, SDSS-II will
continue through mid-2008). It includes five-band photometric data for 217
million objects selected over 8000 square degrees, and 1,048,960 spectra of
galaxies, quasars, and stars selected from 5713 square degrees of that imaging
data. These numbers represent a roughly 20% increment over those of the Fourth
Data Release; all the data from previous data releases are included in the
present release. In addition to "standard" SDSS observations, DR5 includes
repeat scans of the southern equatorial stripe, imaging scans across M31 and
the core of the Perseus cluster of galaxies, and the first spectroscopic data
from SEGUE, a survey to explore the kinematics and chemical evolution of the
Galaxy. The catalog database incorporates several new features, including
photometric redshifts of galaxies, tables of matched objects in overlap regions
of the imaging survey, and tools that allow precise computations of survey
geometry for statistical investigations.Comment: ApJ Supp, in press, October 2007. This paper describes DR5. The SDSS
Sixth Data Release (DR6) is now public, available from http://www.sdss.or
The Seventh Data Release of the Sloan Digital Sky Survey
This paper describes the Seventh Data Release of the Sloan Digital Sky Survey
(SDSS), marking the completion of the original goals of the SDSS and the end of
the phase known as SDSS-II. It includes 11663 deg^2 of imaging data, with most
of the roughly 2000 deg^2 increment over the previous data release lying in
regions of low Galactic latitude. The catalog contains five-band photometry for
357 million distinct objects. The survey also includes repeat photometry over
250 deg^2 along the Celestial Equator in the Southern Galactic Cap. A
coaddition of these data goes roughly two magnitudes fainter than the main
survey. The spectroscopy is now complete over a contiguous area of 7500 deg^2
in the Northern Galactic Cap, closing the gap that was present in previous data
releases. There are over 1.6 million spectra in total, including 930,000
galaxies, 120,000 quasars, and 460,000 stars. The data release includes
improved stellar photometry at low Galactic latitude. The astrometry has all
been recalibrated with the second version of the USNO CCD Astrograph Catalog
(UCAC-2), reducing the rms statistical errors at the bright end to 45
milli-arcseconds per coordinate. A systematic error in bright galaxy photometr
is less severe than previously reported for the majority of galaxies. Finally,
we describe a series of improvements to the spectroscopic reductions, including
better flat-fielding and improved wavelength calibration at the blue end,
better processing of objects with extremely strong narrow emission lines, and
an improved determination of stellar metallicities. (Abridged)Comment: 20 pages, 10 embedded figures. Accepted to ApJS after minor
correction
US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report
This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in
Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference
Recommended from our members
Science Communication in a Digital Age: Social Media and the American Fisheries Society
Social media platforms are effective tools used
to help communicate and increase involvement in cultural, political,
and scientific circles. In 2012, an ad hoc committee was
established to explore online fisheries science communication
and how social media platforms can be utilized by the American
Fisheries Society (AFS). A survey was disseminated to all AFS
units (chapters, sections, divisions) and student subunits to better
understand the current use of social media within the AFS.
A relatively high response rate (82%) provided some confidence
in the survey results—namely, that nearly 69% or more of units
and subunits used social media. Facebook was the dominant
platform used (59%; all others < 15%) and almost exclusively
(97%) for the purpose of communication. Education, outreach,
and member recruitment were other reasons for social media
use. Finally, whether units currently use social media or not at
all, it was recommended that AFS-led workshops and assistance
would increase the usefulness of social media
The Impact of HIV Infection and CD4 Cell Count on the Performance of an Interferon Gamma Release Assay in Patients with Pulmonary Tuberculosis
BACKGROUND:The performance of the tuberculosis specific Interferon Gamma Release Assays (IGRAs) has not been sufficiently documented in tuberculosis- and HIV-endemic settings. This study evaluated the sensitivity of the QuantiFERON TB-Gold In-Tube (QFT-IT) in patients with culture confirmed pulmonary tuberculosis (PTB) in a TB- and HIV-endemic population and the effect of HIV-infection and CD4 cell count on test performance. METHODOLOGY/PRINCIPAL FINDINGS:161 patients with sputum culture confirmed PTB were subjected to HIV- and QFT-IT testing and measurement of CD4 cell count. The QFT-IT was positive in 74% (119/161; 95% CI: 67-81%). Sensitivity was higher in HIV-negative (75/93) than in HIV-positive (44/68) patients (81% vs. 65%, p = 0.02) and increased with CD4 cell count in HIV-positive patients (test for trend p = 0.03). 23 patients (14%) had an indeterminate result and this proportion decreased with increasing CD4 cell count in HIV-positive patients (test for trend p = 0.03). Low CD4 cell count (<300 cells/microl) did not account for all QFT-IT indeterminate nor all negative results. Sensitivity when excluding indeterminate results was 86% (95% CI: 81-92%) and did not differ between HIV-negative and HIV-positive patients (88 vs. 83%, p = 0.39). CONCLUSIONS/SIGNIFICANCE:Sensitivity of the QFT-IT for diagnosing active PTB infection was reasonable when excluding indeterminate results and in HIV-negative patients. However, since the test missed more than 10% of patients, its potential as a rule-out test for active TB disease is limited. Furthermore, test performance is impaired by low CD4 cell count in HIV-positive patients and possibly by other factors as well in both HIV-positive and HIV-negative patients. This might limit the potential of the test in populations where HIV-infection is prevalent
Skeletal Adaptation to Intramedullary Pressure-Induced Interstitial Fluid Flow Is Enhanced in Mice Subjected to Targeted Osteocyte Ablation
Interstitial fluid flow (IFF) is a potent regulatory signal in bone. During mechanical loading, IFF is generated through two distinct mechanisms that result in spatially distinct flow profiles: poroelastic interactions within the lacunar-canalicular system, and intramedullary pressurization. While the former generates IFF primarily within the lacunar-canalicular network, the latter generates significant flow at the endosteal surface as well as within the tissue. This gives rise to the intriguing possibility that loading-induced IFF may differentially activate osteocytes or surface-residing cells depending on the generating mechanism, and that sensation of IFF generated via intramedullary pressurization may be mediated by a non-osteocytic bone cell population. To begin to explore this possibility, we used the Dmp1-HBEGF inducible osteocyte ablation mouse model and a microfluidic system for modulating intramedullary pressure (ImP) to assess whether structural adaptation to ImP-driven IFF is altered by partial osteocyte depletion. Canalicular convective velocities during pressurization were estimated through the use of fluorescence recovery after photobleaching and computational modeling. Following osteocyte ablation, transgenic mice exhibited severe losses in bone structure and altered responses to hindlimb suspension in a compartment-specific manner. In pressure-loaded limbs, transgenic mice displayed similar or significantly enhanced structural adaptation to Imp-driven IFF, particularly in the trabecular compartment, despite up to ∼50% of trabecular lacunae being uninhabited following ablation. Interestingly, regression analysis revealed relative gains in bone structure in pressure-loaded limbs were correlated with reductions in bone structure in unpressurized control limbs, suggesting that adaptation to ImP-driven IFF was potentiated by increases in osteoclastic activity and/or reductions in osteoblastic activity incurred independently of pressure loading. Collectively, these studies indicate that structural adaptation to ImP-driven IFF can proceed unimpeded following a significant depletion in osteocytes, consistent with the potential existence of a non-osteocytic bone cell population that senses ImP-driven IFF independently and potentially parallel to osteocytic sensation of poroelasticity-derived IFF
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