1,112 research outputs found
Self-help and rural development in Kenya
One of the main emphases of the Special Rural Development Programme
in Kenya was supposed to be the involvement of local communities in economic
development efforts. Self-help activity in the past has been strongly preoccupied
with projects which absorb, rather than produce resources. In this
paper the six S.R.D.P. areas are examined in terms of the intensity of socalled
'economic' or 'economy developing' self-help activity versus the
'social/domestic' or 'welfare' variety, and a comparison is made with selected
non-S.R.D.P. areas. It is found that the preponderance of 'welfare' projects
is as strong or stronger in the S.R.D.P. areas as elsewhere. Various means
for promoting self-help along more economically productive lines are then
discussed, along with the existing approaches and structures, and some alternatives
are suggested
Policy Point—Counterpoint: Do African American Athletes Have an Obligation to Fight Against Racial Injustice?
This policy point-counterpoint, authored by history Ph.D. candidates BJ Marach and J. Marcos Reynolds, frames black-athletic activism as a longstanding historical debate reaching back to the late 1800s. Both argue for the efficacy of such activism and ground their analysis in the “Revolt of the Black Athlete” of the late 1960s. From here they diverge. Marach contends that black athletes are under no obligation to protest racial injustice, while Reynolds concludes that their platform and position within the black community requires that they act
Aerodynamic Analysis of the Truss-Braced Wing Aircraft Using Vortex-Lattice Superposition Approach
The SUGAR Truss-BracedWing (TBW) aircraft concept is a Boeing-developed N+3 aircraft configuration funded by NASA ARMD FixedWing Project. This future generation transport aircraft concept is designed to be aerodynamically efficient by employing a high aspect ratio wing design. The aspect ratio of the TBW is on the order of 14 which is significantly greater than those of current generation transport aircraft. This paper presents a recent aerodynamic analysis of the TBW aircraft using a conceptual vortex-lattice aerodynamic tool VORLAX and an aerodynamic superposition approach. Based on the underlying linear potential flow theory, the principle of aerodynamic superposition is leveraged to deal with the complex aerodynamic configuration of the TBW. By decomposing the full configuration of the TBW into individual aerodynamic lifting components, the total aerodynamic characteristics of the full configuration can be estimated from the contributions of the individual components. The aerodynamic superposition approach shows excellent agreement with CFD results computed by FUN3D, USM3D, and STAR-CCM+
The Mid-Infrared Emission of M87
We discuss Subaru and Spitzer Space Telescope imaging and spectroscopy of M87
in the mid-infrared from 5-35 um. These observations allow us to investigate
mid-IR emission mechanisms in the core of M87 and to establish that the
flaring, variable jet component HST-1 is not a major contributor to the mid-IR
flux. The Spitzer data include a high signal-to-noise 15-35 m spectrum of
the knot A/B complex in the jet, which is consistent with synchrotron emission.
However, a synchrotron model cannot account for the observed {\it nuclear}
spectrum, even when contributions from the jet, necessary due to the degrading
of resolution with wavelength, are included. The Spitzer data show a clear
excess in the spectrum of the nucleus at wavelengths longer than 25 um, which
we model as thermal emission from cool dust at a characteristic temperature of
55 \pm 10 K, with an IR luminosity \sim 10^{39} {\rm ~erg ~s^{-1}}. Given
Spitzer's few-arcsecond angular resolution, the dust seen in the nuclear
spectrum could be located anywhere within ~5'' (390 pc) of the nucleus. In any
case, the ratio of AGN thermal to bolometric luminosity indicates that M87 does
not contain the IR-bright torus that classical unified AGN schemes invoke.
However, this result is consistent with theoretical predictions for
low-luminosity AGNsComment: 9 pages, 7 figures, ApJ, in pres
Lrg1 Regulates β (1, 3)-Glucan Masking in Candida albicans through the Cek1 MAP Kinase Pathway
Candida albicans is among the most prevalent opportunistic human fungal pathogens. The ability to mask the immunogenic polysaccharide β (1,3)-glucan from immune detection via a layer of mannosylated proteins is a key virulence factor of C. albicans. We previously reported that hyperactivation of the Cek1 mitogen-activated protein (MAP) kinase pathway promotes β (1,3)-glucan exposure. In this communication, we report a novel upstream regulator of Cek1 activation and characterize the impact of Cek1 activity on fungal virulence. Lrg1 encodes a GTPase-activating protein (GAP) that has been suggested to inhibit the GTPase Rho1. We found that disruption of LRG1 causes Cek1 hyperactivation and β (1,3)-glucan unmasking. However, when GTPase activation was measured for a panel of GTPases, the lrg1ΔΔ mutant exhibited increased activation of Cdc42 and Ras1 but not Rho1 or Rac1. Unmasking and Cek1 activation in the lrg1ΔΔ mutant can be blocked by inhibition of the Ste11 MAP kinase kinase kinase (MAPKKK), indicating that the lrg1ΔΔ mutant acts through the canonical Cek1 MAP kinase cascade. In order to determine how Cek1 hyperactivation specifically impacts virulence, a doxycycline-repressible hyperactive STE11ΔN467 allele was expressed in C. albicans. In the absence of doxycycline, this allele overexpressed STE11ΔN467, which induced production of proinflammatory tumor necrosis factor alpha (TNF-α) from murine macrophages. This in vitrophenotype correlates with decreased colonization and virulence in a mouse model of systemic infection. The mechanism by which Ste11ΔN467 causes unmasking was explored with RNA sequencing (RNA-Seq) analysis. Overexpression of Ste11ΔN467 caused upregulation of the Cph1 transcription factor and of a group of cell wall-modifying proteins which are predicted to impact cell wall architecture
Comparative transcriptomic analysis of Porphyromonas gingivalis biofilm and planktonic cells
<p>Abstract</p> <p>Background</p> <p><it>Porphyromonas gingivalis </it>in subgingival dental plaque, as part of a mature biofilm, has been strongly implicated in the onset and progression of chronic periodontitis. In this study using DNA microarray we compared the global gene expression of a <it>P. gingivalis </it>biofilm with that of its planktonic counterpart grown in the same continuous culture.</p> <p>Results</p> <p>Approximately 18% (377 genes, at 1.5 fold or more, <it>P</it>-value < 0.01) of the <it>P. gingivalis </it>genome was differentially expressed when the bacterium was grown as a biofilm. Genes that were down-regulated in biofilm cells, relative to planktonic cells, included those involved in cell envelope biogenesis, DNA replication, energy production and biosynthesis of cofactors, prosthetic groups and carriers. A number of genes encoding transport and binding proteins were up-regulated in <it>P. gingivalis </it>biofilm cells. Several genes predicted to encode proteins involved in signal transduction and transcriptional regulation were differentially regulated and may be important in the regulation of biofilm growth.</p> <p>Conclusion</p> <p>This study analyzing global gene expression provides insight into the adaptive response of <it>P. gingivalis </it>to biofilm growth, in particular showing a down regulation of genes involved in growth and metabolic activity.</p
HIV Viral Load Monitoring in Resource-Limited Regions: Optional or Necessary?
Although it is a standard practice in high-income countries, determination of the human immunodeficiency virus (HIV) load is not recommended in developing countries because of the costs and technical constraints. As more and more countries establish capacity to provide second-line therapy, and as costs and technological constraints associated with viral load testing decrease, the question of whether determination of the viral load is necessary deserves attention. Viral load testing could increase in importance as a guide for clinical decisions on when to switch to second-line treatment and on how to optimize the duration of the first-line treatment regimen. In addition, the viral load is a particularly useful tool for monitoring adherence to treatment, performing sentinel surveillance, and diagnosing HIV infection in children aged <18 months. Rather than considering viral load data to be an unaffordable luxury, efforts should be made to ensure that viral load testing becomes affordable, simple, and easy to use in resource-limited setting
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