372 research outputs found
Analog Particle Production Model for General Classes of Taub-NUT Black Holes
We derive a correspondence between the Hawking radiation spectra emitted from
general classes of Taub-NUT black holes with that induced by the relativistic
motion of an accelerated Dirichlet boundary condition (i.e.\ a perfectly
reflecting mirror) in (1+1)-dimensional flat spacetime. We demonstrate that the
particle and energy spectra is thermal at late-times and that particle
production is suppressed by the NUT parameter. We also compute the radiation
spectrum in the rotating, electrically charged (Kerr-Newman) Taub-NUT scenario,
and the extremal case, showing explicitly how these parameters affect the
outgoing particle and energy fluxes.Comment: 9+3 pages, 14 figure
Effects of Horizons on Entanglement Harvesting
We study the effects of horizons on the entanglement harvested between two
Unruh-DeWitt detectors via the use of moving mirrors with and without strict
horizons. The entanglement reveals the sensitivity of the entanglement
harvested to the global dynamics of the trajectories disclosing aspects of the
effect that global information loss (where incoming massless scalar field modes
from past null infinity cannot reach right future null infinity) has on local
particle detectors. We also show that entanglement harvesting is insensitive to
the sign of emitted radiation flux.Comment: Expanded discussions and added references. New appendix on numerical
convergence adde
The cytoplasmic domain of the Plasmodium falciparum ligand EBA-175 is essential for invasion but not protein trafficking
The invasion of host cells by the malaria parasite Plasmodium falciparum requires specific protein–protein interactions between parasite and host receptors and an intracellular translocation machinery to power the process. The transmembrane erythrocyte binding protein-175 (EBA-175) and thrombospondin-related anonymous protein (TRAP) play central roles in this process. EBA-175 binds to glycophorin A on human erythrocytes during the invasion process, linking the parasite to the surface of the host cell. In this report, we show that the cytoplasmic domain of EBA-175 encodes crucial information for its role in merozoite invasion, and that trafficking of this protein is independent of this domain. Further, we show that the cytoplasmic domain of TRAP, a protein that is not expressed in merozoites but is essential for invasion of liver cells by the sporozoite stage, can substitute for the cytoplasmic domain of EBA-175. These results show that the parasite uses the same components of its cellular machinery for invasion regardless of the host cell type and invasive form
Degree of explanation
Partial explanations are everywhere. That is, explanations citing causes that explain some but not all of an effect are ubiquitous across science, and these in turn rely on the notion of degree of explanation. I argue that current accounts are seriously deficient. In particular, they do not incorporate adequately the way in which a cause’s explanatory importance varies with choice of explanandum. Using influential recent contrastive theories, I develop quantitative definitions that remedy this lacuna, and relate it to existing measures of degree of causation. Among other things, this reveals the precise role here of chance, as well as bearing on the relation between causal explanation and causation itself
Old Bulloch Personalities
The sixth issue of Southern Folkways Journal Review contains poems handed down by three different Bulloch County families, a paper on the Salzburgers, an interview with Daisy Trapnell, an article on Bulloch County personality “Bitin’ Jake,” a letter concerning Isaac Chadburn Daniel, a query concerning the lives of John and Robert Dunwoody, and four sketches by Rita Turner Wall.https://digitalcommons.georgiasouthern.edu/bchs-pubs/1027/thumbnail.jp
Exposure to Household Air Pollution from Biomass Cookstoves and Blood Pressure Among Women in Rural Honduras: A Cross‐Sectional Study
Growing evidence links household air pollution exposure from biomass cookstoves with elevated blood pressure. We assessed cross‐sectional associations of 24‐hour mean concentrations of personal and kitchen fine particulate matter (PM2.5), black carbon (BC), and stove type with blood pressure, adjusting for confounders, among 147 women using traditional or cleaner‐burning Justa stoves in Honduras. We investigated effect modification by age and body mass index. Traditional stove users had mean (standard deviation) personal and kitchen 24‐hour PM2.5 concentrations of 126 μg/m3 (77) and 360 μg/m3 (374), while Justa stove users’ exposures were 66 μg/m3 (38) and 137 μg/m3(194), respectively. BC concentrations were similarly lower among Justa stove users. Adjusted mean systolic blood pressure was 2.5 mm Hg higher (95% CI, 0.7‐4.3) per unit increase in natural log‐transformed kitchen PM2.5 concentration; results were stronger among women of 40 years or older (5.2 mm Hg increase, 95% CI, 2.3‐8.1). Adjusted odds of borderline high and high blood pressure (categorized) were also elevated (odds ratio = 1.5, 95% CI, 1.0‐2.3). Some results included null values and are suggestive. Results suggest that reduced household air pollution, even when concentrations exceed air quality guidelines, may help lower cardiovascular disease risk, particularly among older subgroups
From Aaron to Ivanhoe
A collection of Bulloch County history materials compiled by Charles Bonds, Dorothy Brannen, Maggie Collins, Dan Good, Nkenge Jackson, Evelyn Mabry, Carolyn Postell, Robert M. Seel, and Rita Turner Wall. Included are a brief history of Bulloch County, an article on local 19th century architecture, two accounts on county history by Rita Turner Wall, a short history of Willow Hill School, a report on the research on Willow Hill School, “Extinct Towns in Bulloch County,” “Pretoria Station,” the biographies of Beatrice Riggs and Laura Bell Hendley Martin, three articles from the Bulloch Times on the memories of a Confederate veteran and the 1865 Census of Bulloch County. The index to this collection was compiled by Julius Ariail.https://digitalcommons.georgiasouthern.edu/bchs-pubs/1014/thumbnail.jp
Dynamical derivation of Bode's law
In a planetary or satellite system, idealized as n small bodies in initially
coplanar, concentric orbits around a large central body, obeying Newtonian
point-particle mechanics, resonant perturbations will cause dynamical evolution
of the orbital radii except under highly specific mutual relationships, here
derived analytically apparently for the first time. In particular, the most
stable situation is achieved (in this idealized model) only when each planetary
orbit is roughly twice as far from the Sun as the preceding one, as observed
empirically already by Titius (1766) and Bode (1778) and used in both the
discoveries of Uranus (1781) and the Asteroid Belt (1801). ETC.Comment: 27 page
The First HET Planet: A Companion to HD 37605
We report the first detection of a planetary-mass companion to a star using
the High Resolution Spectrograph (HRS) of the Hobby-Eberly Telescope (HET). The
HET-HRS now gives routine radial velocity precision of 2-3 m/s for high SNR
observations of quiescent stars. The planetary-mass companion to the metal-rich
K0V star HD37605 has an orbital period of 54.23 days, an orbital eccentricity
of 0.737, and a minimum mass of 2.84 Jupiter masses. The queue-scheduled
operation of the Hobby-Eberly Telescope enabled us to discovery of this
relatively short-period planet with a total observation time span of just two
orbital periods. The ability of queue-scheduled large-aperture telescopes to
respond quickly to interesting and important results demonstrates the power of
this new approach in searching for extra-solar planets as well as in other ares
of research requiring rapid response time critical observations.Comment: 4 Pages, 2 figures. Accepted in Astrophysical Journal Letters,
http://austral.as.utexas.edu/planets/hd37605/hd37605.htm
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