469 research outputs found
Brane World Cosmology, the CMB and the Radion
Recent developments in the theory of extra dimensions have opened up avenues
to confront such theories with cosmological tests. We discuss a brane-world
model with a bulk scalar field, motivated by supergravity. The low-energy
effective action is derived and physical constraints on the parameters of the
model discussed. The cosmological evolution of the brane-world moduli is
investigated and it is shown that one of the moduli is a quintessence field.
The CMB predictions are computed. Finally, the possibility that the radion
field in brane-worlds could be a chameleon field is investigated.Comment: 11 pages, 6 figures, to appear in the proceedings of the DPU
Workshop: The Density Fluctuations in the Universe: Beyond the Inflaton
Paradigm (Athens, June 2004
Layer-by-Layer Encapsulation of Probiotics for Delivery to the Microbiome
Recent discoveries in biology and microbiology have highlighted the importance of the gastrointestinal (GI) microbiome in regulating human health and disease. Thus, the delivery of probiotics to influence and modulate microbiome compositions can potentially impact the treatment of a number of human diseases. Unfortunately, biological challenges encountered during oral delivery have limited the translation of many probiotic-delivering technologies. Here, we report a layer-by-layer (LbL) method for the encapsulation of probiotics to directly address these challenges by protecting probiotics from GI tract insults while facilitating both mucoadhesion and direct growth on intestinal surfaces
An exploration of concepts of community through a case study of UK university web production
The paper explores the inter-relation and differences between the concepts of occupational community, community of practice, online community and social network. It uses as a case study illustration the domain of UK university web site production and specifically a listserv for those involved in it. Different latent occupational communities are explored, and the potential for the listserv to help realize these as an active sense of community is considered. The listserv is not (for most participants) a tight knit community of practice, indeed it fails many criteria for an online community. It is perhaps best conceived as a loose knit network of practice, valued for information, implicit support and for the maintenance of weak ties. Through the analysis the case for using strict definitions of the theoretical concepts is made
Awareness, Knowledge, and Travel-Related Risk Factors for Zika Virus Among Latinas Attending a Federally Qualified Health Center in Rural North Carolina
BACKGROUND The Zika virus (ZIKV) epidemic that began in 2015 presented a risk for ZIKV infection among persons who traveled to ZIKV-affected countries. Latinas in North Carolina and their sexual partners may be exposed to ZIKV when traveling to these regions.METHODS We administered a cross-sectional survey, measuring ZIKV risk and knowledge, to a convenience sample of 262 reproductive-age Latinas attending a Federally Qualified Health Center in rural North Carolina. We described ZIKV risk and knowledge in the sample, and compared responses between those who were pregnant or recently pregnant, and those who were not pregnant. We further identified factors associated with 1) awareness of ZIKV and 2) high knowledge of ZIKV sequelae and prevention among those who were aware of ZIKV, using log-binomial regression.RESULTS Two-thirds of participants had ever heard of ZIKV, which was positively associated with educational attainment. Most participants aware of ZIKV had moderate/high knowledge of ZIKV transmission (92.5%) and symptoms (73.2%), but knowledge of preventing sexual and congenital transmission was limited. Travel was infrequent among pregnant or recently pregnant participants (5.4%) and their partners (7.1%). Despite low risk for ZIKV infection, participants were willing to practice ZIKV prevention.LIMITATIONS Our study is limited by a lack of generalizability to Latinas in other regions of the country, self-reporting bias, and lack of survey validation as an indicator of English language proficiency.CONCLUSIONS Providers should identify patients likely to become pregnant and travel to high-risk areas, inquire about partner travel history, and offer culturally appropriate ZIKV risk counseling
Endogenous Risks and Learning in Climate Change Decision Analysis
We analyze the effects of risks and learning on climate change decisions. A two-stage, dynamic, climate change stabilization problem is formulated. The explicit incorporation of ex-post learning induces risk aversion among ex-ante decisions, which is characterized in linear models by VaR- and CVaR-type risk measures. Combined with explicit introduction of "safety" constraints, it creates a "hit-or-miss" type decision-making situation and shows that, even in linear models, learning may lead to either less-or more restrictive ex-ante emission reductions. We analyze stylized elements of the model in order to identify the key factors driving outcomes, in particular, the critical role of quantiles of probability distributions characterizing key uncertainties
The association of female sex with management and mortality in patients with Staphylococcus aureus bacteraemia
Objectives: The association of biological female sex with outcome in patients with Staphylococcus aureus bacteraemia remains unresolved. The aim of this study was to determine the independent association of female sex with management and mortality in patients with S. aureus bacteraemia.Methods: This is a post hoc analysis of prospectively collected data from the S. aureus Bacteraemia Group Prospective Cohort Study. Adult patients with monomicrobial S. aureus bacteraemia at Duke University Medical Center were enrolled from 1994 to 2020. Univariable and multivariable Cox regression analyses were performed to assess differences in management and mortality between females and males.Results: Among 3384 patients with S. aureus bacteraemia, 1431 (42%) were women. Women were, as compared with men, more often Black (581/1431 [41%] vs. 620/1953 [32%], p < 0.001), haemodialysis dependent (309/1424 [22%] vs. 334/1940 [17%], p 0.001) and more likely to be infected with methicillinresistant S. aureus (MRSA) (697/1410 [49%] MRSA in women vs. 840/1925 [44%] MRSA in men, p 0.001). Women received shorter durations of antimicrobial treatment (median 24 [interquartile range 14-42] vs. 28 [interquartile range 14-45] days, p 0.005), and were less likely to undergo transesophageal echocardiography as compared with men (495/1430 [35%] vs. 802/1952 [41%], p < 0.001). Despite these differences, female sex was not associated with 90-day mortality in either univariable (388/1431 [27%] in women vs. 491/1953 [25%] in men, p 0.204) or multivariable analysis (adjusted hazard ratio for women 0.98 [95% CI, 0.85-1.13]).Discussion: Despite significant differences in patient characteristics, disease characteristics, and management, women and men with S. aureus bacteraemia have a similar mortality risk. Annette C. Westgeest, Clin Microbiol Infect 2023;29:1182Immunogenetics and cellular immunology of bacterial infectious disease
Black Hole Spin via Continuum Fitting and the Role of Spin in Powering Transient Jets
The spins of ten stellar black holes have been measured using the
continuum-fitting method. These black holes are located in two distinct classes
of X-ray binary systems, one that is persistently X-ray bright and another that
is transient. Both the persistent and transient black holes remain for long
periods in a state where their spectra are dominated by a thermal accretion
disk component. The spin of a black hole of known mass and distance can be
measured by fitting this thermal continuum spectrum to the thin-disk model of
Novikov and Thorne; the key fit parameter is the radius of the inner edge of
the black hole's accretion disk. Strong observational and theoretical evidence
links the inner-disk radius to the radius of the innermost stable circular
orbit, which is trivially related to the dimensionless spin parameter a_* of
the black hole (|a_*| < 1). The ten spins that have so far been measured by
this continuum-fitting method range widely from a_* \approx 0 to a_* > 0.95.
The robustness of the method is demonstrated by the dozens or hundreds of
independent and consistent measurements of spin that have been obtained for
several black holes, and through careful consideration of many sources of
systematic error. Among the results discussed is a dichotomy between the
transient and persistent black holes; the latter have higher spins and larger
masses. Also discussed is recently discovered evidence in the transient sources
for a correlation between the power of ballistic jets and black hole spin.Comment: 30 pages. Accepted for publication in Space Science Reviews. Also to
appear in hard cover in the Space Sciences Series of ISSI "The Physics of
Accretion onto Black Holes" (Springer Publisher). Changes to Sections 5.2,
6.1 and 7.4. Section 7.4 responds to Russell et al. 2013 (MNRAS, 431, 405)
who find no evidence for a correlation between the power of ballistic jets
and black hole spi
Search for and Using Genetic Programming Event Selection
We apply a genetic programming technique to search for the double Cabibbo
suppressed decays and .
We normalize these decays to their Cabibbo favored partners and find
\Lambda_c^+ \to p K^+ \pi^-\Lambda_c^+ \to p K^-
\pi^+ and D_s^+ \to K^+ K^+
\pi^-D_s^+ \to K^+ K^- \pi^+ where
the first errors are statistical and the second are systematic. Expressed as
90% confidence levels (CL), we find and respectively.
This is the first successful use of genetic programming in a high energy
physics data analysis.Comment: 10 page
Measurement of the D+ and Ds+ decays into K+K-K+
We present the first clear observation of the doubly Cabibbo suppressed decay
D+ --> K-K+K+ and the first observation of the singly Cabibbo suppressed decay
Ds+ --> K-K+K+. These signals have been obtained by analyzing the high
statistics sample of photoproduced charm particles of the FOCUS(E831)
experiment at Fermilab. We measure the following relative branching ratios:
Gamma(D+ --> K-K+K+)/Gamma(D+ --> K-pi+pi+) = (9.49 +/- 2.17(statistical) +/-
0.22(systematic))x10^-4 and Gamma(Ds+ --> K-K+K+)/Gamma(Ds+ --> K-K+pi+) =
(8.95 +/- 2.12(statistical) +2.24(syst.) -2.31(syst.))x10^-3.Comment: 10 pages, 8 figure
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