1,805 research outputs found
Exploration into small, rural, declining, near end of life-cycle church turnaround in the Wesleyan and United Methodist Church
https://place.asburyseminary.edu/ecommonsatsdissertations/1832/thumbnail.jp
Malaria-filaria coinfection in mice makes malarial disease more severe unless filarial infection achieves patency
Coinfections are common in natural populations, and the literature suggests that helminth coinfection readily affects how the immune system manages malaria. For example, type 1ādependent control of malaria parasitemia might be impaired by the type 2 milieu of preexisting helminth infection. Alternatively, immunomodulatory effects of helminths might affect the likelihood of malarial immunopathology. Using rodent models of lymphatic filariasis (Litomosoides sigmodontis) and noncerebral malaria (clone AS Plasmodium chabaudi chabaudi), we quantified disease severity, parasitemia, and polyclonal splenic immune responses in BALB/c mice. We found that coinfected mice, particularly those that did not have microfilaremia (Mf), had more severe anemia and loss of body mass than did mice with malaria alone. Even when controlling for parasitemia, malaria was most severe in Mf coinfected mice, and this was associated with increased interferon-g responsiveness. Thus, in Mf mice, filariasis upset a delicate immunological balance in malaria infection and exacerbated malaria-induced immunopathology. Helminth infections are prevalent throughout tropical regions where malaria is transmitted [1ā5]. Interactions among infections commonly alter disease severity [6, 7], and malaria-helminth coinfection can either exac
Unidirectional Propagation of an Ultra-Short Electromagnetic Pulse in a Resonant Medium with High Frequency Stark Shift
We consider in the unidirectional approximation the propagation of an ultra
short electromagnetic pulse in a resonant medium consisting of molecules
characterized by a transition operator with both diagonal and non-diagonal
matrix elements. We find the zero-curvature representation of the reduced
Maxwell-Bloch equations in the sharp line limit. This can be used to develop
the inverse scattering transform method to solve these equations. Finally we
obtain two types of exact traveling pulse solutions, one with the usual
exponential decay and another with an algebraic decay.Comment: Latex, 10 pages, no figure
The online obstacle : a study of African-American enterprise on the Internet
Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 73-74).Iconic Web companies based in the US, along the likes of Google, Facebook, and Twitter, have exhibited some racial/ethnic diversity among their founders, yet there appears to be a dearth of African-Americans in the group. In this thesis I conduct an empirical investigation into the potential existence of a set of impediments to blockbuster success for African-American founded consumer Internet companies -- or an "online obstacle," as I have chosen to term the condition. In utilizing a short-form survey and telephone interviews to collect the thoughts and opinions of 16 black entrepreneurs who have made at least one attempt at launching a consumer Internet start-up, I document three recurrent themes. First, there do not appear to be enough African-American graduates of engineering and computer science disciplines to facilitate creation of promising Internet ventures that could achieve blockbuster status. Second, black Web entrepreneurs by-and-large have not achieved the heights of capital infusion that seems to be necessary to transition a concept from "successful" to "blockbuster." Lastly, African-American founders of consumer Internet companies do not in any significant numbers appear to live and play in the start-up ecosystem that is Silicon Valley, inhibiting development of relationships and access to resources needed to ascend to blockbuster status online. Overall, my findings suggest that the online obstacle I seek to identify is very much a collection of barriers that has a direct correlation to issues black entrepreneurs have spoken about for decades, suggesting that any revealed online obstacle very much lacks an online origin.by Allen T. Lamb.M.B.A
Body-surface pressure data on two monoplane-wing missile configurations with elliptical cross sections at Mach 2.50
Tabulated body surface pressure data for two monoplane-wing missile configurations are presented and analyzed. Body pressure data are presented for body-alone, body-tail, and body-wing-tail combinations. For the lost combination, data are presented for tail-fin deflection angles of 0 deg and 30 deg to simulate pitch, yaw, and roll control for both configurations. The data cover angles of attack from -5 deg to 25 deg and angles of roll from 0 deg to 90 deg at a Mach number of 2.50 and a Reynolds number of 6.56 x 1,000,000 per meter. Very consistent, systematic trends with angle of attack and angle of roll were observed in the data, and very good symmetry was found at a roll angle of 0 deg. Body pressures depended strongly on the local body cross-section shape, with very little dependence on the upstream shape. Undeflected fins had only a small influence on the pressures on the aft end of the body; however, tail-fin deflections caused large changes in the pressures
Most of the response elicited against Wolbachia surface protein in filarial nematode infection is due to the infective larval stage
Discovery of New, Dust-Poor B[e] Supergiants in the Small Magellanic Cloud
We present the discovery of three new B[e] supergiants (sgB[e] stars) in the
Small Magellanic Cloud (SMC). All three stars (R15, R38, and R48) were
identified in the course of our Runaways and Isolated O Type Star Spectroscopic
Survey of the SMC (RIOTS4). The stars show optical spectra that closely
resemble those of previously known B[e] stars, presenting numerous
low-ionization forbidden and permitted emission lines such as [Fe II] and Fe
II. Furthermore, our stars have luminosities of log(L/L_sun) > 4, demonstrating
that they are supergiants. However, we find lower infrared excesses and weaker
forbidden emission lines than for previously identified B[e] supergiants. Thus
our stars appear to either have less material in their circumstellar disks than
other sgB[e] stars, or the circumstellar material has lower dust content. We
suggest that these may constitute a new subclass of dust-poor sgB[e] stars.Comment: 7 pages, 6 figures, accepted to Ap
Two-Pulse Propagation in a Partially Phase-Coherent Medium
We analyze the effects of partial coherence of ground state preparation on
two-pulse propagation in a three-level medium, in contrast to
previous treastments that have considered the cases of media whose ground
states are characterized by probabilities (level populations) or by probability
amplitudes (coherent pure states). We present analytic solutions of the
Maxwell-Bloch equations, and we extend our analysis with numerical solutions to
the same equations. We interpret these solutions in the bright/dark dressed
state basis, and show that they describe a population transfer between the
bright and dark state. For mixed-state media with partial ground
state phase coherence the dark state can never be fully populated. This has
implications for phase-coherent effects such as pulse matching, coherent
population trapping, and electromagnetically induced transparency (EIT). We
show that for partially phase-coherent three-level media, self induced
transparency (SIT) dominates EIT and our results suggest a corresponding
three-level area theorem.Comment: 29 pages, 12 figures. Submitted to Phys. Rev.
Hydrodynamics of confined colloidal fluids in two dimensions
We apply a hybrid Molecular Dynamics and mesoscopic simulation technique to
study the dynamics of two dimensional colloidal discs in confined geometries.
We calculate the velocity autocorrelation functions, and observe the predicted
long time hydrodynamic tail that characterizes unconfined fluids, as
well as more complex oscillating behavior and negative tails for strongly
confined geometries. Because the tail of the velocity autocorrelation
function is cut off for longer times in finite systems, the related diffusion
coefficient does not diverge, but instead depends logarithmically on the
overall size of the system.Comment: RevTex 13 pages, 9 figure
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