4,849 research outputs found
Enrollment in YFV Vaccine Trial: An Evaluation of Recruitment Outcomes Associated with a Randomized Controlled Double-Blind Trial of a Live Attenuated Yellow Fever Vaccine
This investigation evaluated several factors associated with diverse participant enrollment of a clinical trial assessing safety, immunogenicity, and comparative viremia associated with administration of 17-D live, attenuated yellow fever vaccine given alone or in combination with human immune globulin. We obtained baseline participant information (e.g., sociodemographic, medical) and followed recruitment outcomes from 2005 to 2007. Of 355 potential Yellow Fever vaccine study participants, 231 cases were analyzed. Strong interest in study participation was observed among racial and ethnically diverse persons with 36.34% eligible following initial study screening, resulting in 18.75% enrollment. The percentage of white participants increased from 63.66% (prescreened sample) to 81.25% (enrollment group). The regression model was significant with white race as a predictor of enrollment (OR=2.744, 95% CI=1.415-5.320, p=0.003).In addition, persons were more likely to enroll via direct outreach and referral mechanisms compared to mass advertising (OR=2.433, 95% CI=1.102-5.369). The findings indicate that racially diverse populations can be recruited to vaccine clinical trials, yet actual enrollment may not reflect that diversit
Unusual solar energetic proton fluxes at 1 AU within an interplanetary CME
In mid December 2006 several flares on the Sun occurred in rapid succession, spawning several CMEs and bathing the Earth in multiple solar energetic particle (SEP) events. O
ne such SEP occurring on December 15th was observed at the Earth just as an interplanetary CME (ICME) from a previous flare on December 13th was transiting the Earth. Although solar wind observations during this time show typical
energetic proton fluxes from the prior SEP and IP shock driven ahead of the ICME, as the ICME passes the Earth unusual energetic particle signatures are observed. Measurem
ents from ACE, Wind, and STEREO show unusual proton flux variations at energies ranging from ∼3 MeV up to greater than 70 MeV. Within the Earth’s magnetosphere Polar HIST also sees unusual proton flux v ariations at energies greater than 10 MeV while crossing open field lines in the southern polar cap. However, no such variation in the energetic proton flux is observed at the GOES 10 or GOES 11 spacecraft in geosy nchronous orbit. Differential fluxes observed at GOES 12 in the 15-40 MeV energy range show some
variation. However, the overall energetic particle signature within the ICME at GEO orbits remains unclear. This event illustrates the need for caution when using GEO data in detailed studies of SEP events and in interplanetary models of energetic particle transport to 1 AU
Multipoint, high time resolution galactic cosmic ray observations associated with two interplanetary coronal mass ejections
[1] Galactic cosmic rays (GCRs) play an important role in our understanding of the interplanetary medium (IPM). The causes of their short timescale variations, however, remain largely unexplored. In this paper, we compare high time resolution, multipoint space-based GCR data to explore structures in the IPM that cause these variations. To ensure that features we see in these data actually relate to conditions in the IPM, we look for correlations between the GCR time series from two instruments onboard the Polar and INTEGRAL (International Gamma Ray Astrophysical Laboratory) satellites, respectively inside and outside Earth\u27s magnetosphere. We analyze the period of 18–24 August 2006 during which two interplanetary coronal mass ejections (ICMEs) passed Earth and produced a Forbush decrease (Fd) in the GCR flux. We find two periods, for a total of 10 h, of clear correlation between small-scale variations in the two GCR time series during these 7 days, thus demonstrating that such variations are observable using space-based instruments. The first period of correlation lasted 6 h and began 2 h before the shock of the first ICME passed the two spacecraft. The second period occurred during the initial decrease of the Fd, an event that did not conform to the typical one- or two-step classification of Fds. We propose that two planar magnetic structures preceding the first ICME played a role in both periods: one structure in driving the first correlation and the other in initiating the Fd
Phagocytes and the Lung
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72927/1/j.1749-6632.1997.tb46258.x.pd
Short-period variability in the galactic cosmic ray intensity: High statistical resolution observations and interpretation around the time of a Forbush decrease in August 2006
On 20 August 2006 a Forbush decrease observed at Polar in the Earth's magnetosphere was also seen at the INTEGRAL spacecraft outside the magnetosphere during a very active time in the solar wind. High-resolution energetic particle data from ACE SIS, the Polar high-sensitivity telescope, and INTEGRAL's Ge detector saturation rate, which measures the galactic cosmic ray (GCR) background with a threshold of similar to 200 MeV, show similar, short-period GCR variations in and around the Forbush decrease. Focusing upon the GCR intensity within a 3-day interval from 19 August 2006 to 21 August 2006 reveals many intensity variations in the GCR on a variety of time scales and amplitudes. These intensity variations are greater than the 3 sigma error in all the data sets used. The fine structures in the GCR intensities along with the Forbush decrease are propagated outward from ACE to the Earth with very little change. The solar wind speed stays relatively constant during these periods, indicating that parcels of solar wind are transporting the GCR population outward in the heliosphere. This solar wind convection of GCR fine structure is observed for both increases and decreases in GCR intensity, and the fine structure increases and decreases are bracketed by solar wind magnetic field discontinuities associated with interplanetary coronal mass ejection (ICME) magnetosheath regions, clearly seen as discontinuous rotations of the field components at ACE and at Wind. Interestingly, the electron heat flux shows different flux tube connectivity also associated with the different regions of the ICME and magnetosheath. Gosling et al. (2004) first discussed the idea that solar energetic particle intensities commonly undergo dispersionless modulation in direct association with discontinuous changes in the solar wind electron strahl. The observations show that the intensity levels in the GCR flux may undergo a similar partitioning, possibly because of the different magnetic field regions having differing magnetic topologies
Equal Pay for All: An Idea Whose Time Has Not, and Will Not, Come
The proposal on offer is a radical form of egalitarianism. Under it, each citizen receives the same income, regardless of profession or indeed whether he or she works or not. This proposal is bad for two reasons. First, it is inefficient. It would eliminate nearly all incentive to work, thereby shrinking national income and leaving all citizens poorly off (albeit equally poorly off). I illustrate this inefficiency via an indifference curve analysis. Second, the proposal would be regarded as unjust by almost everyone. The empirical work on justice makes this plain. Equal pay for equal work is desirable; equal pay no matter what is something else entirely. It is an idea not likely to find adherents
Privacy Architectures: Reasoning About Data Minimisation and Integrity
Privacy by design will become a legal obligation in the European Community if
the Data Protection Regulation eventually gets adopted. However, taking into
account privacy requirements in the design of a system is a challenging task.
We propose an approach based on the specification of privacy architectures and
focus on a key aspect of privacy, data minimisation, and its tension with
integrity requirements. We illustrate our formal framework through a smart
metering case study.Comment: appears in STM - 10th International Workshop on Security and Trust
Management 8743 (2014
Flicker Light–Induced Retinal Vasodilation in Diabetes and Diabetic Retinopathy
10.2337/dc09-0075Diabetes Care32112075-2080DICA
Kinetics and Identities of Extracellular Peptidases in Subsurface Sediments of the White Oak River Estuary, North Carolina
Anoxic subsurface sediments contain communities of heterotrophic microorganisms that metabolize organic carbon at extraordinarily low rates. In order to assess the mechanisms by which subsurface microorganisms access detrital sedimentary organic matter, we measured kinetics of a range of extracellular peptidases in anoxic sediments of the White Oak River Estuary, NC. Nine distinct peptidase substrates were enzymatically hydrolyzed at all depths. Potential peptidase activities (Vmax) decreased with increasing sediment depth, although Vmax expressed on a per-cell basis was approximately the same at all depths. Half-saturation constants (Km) decreased with depth, indicating peptidases that functioned more efficiently at low substrate concentrations. Potential activities of extracellular peptidases acting on molecules that are enriched in degraded organic matter (d-phenylalanine and l-ornithine) increased relative to enzymes that act on l-phenylalanine, further suggesting microbial community adaptation to access degraded organic matter. Nineteen classes of predicted, exported peptidases were identified in genomic data from the same site, of which genes for class C25 (gingipain-like) peptidases represented more than 40% at each depth. Methionine aminopeptidases, zinc carboxypeptidases, and class S24-like peptidases, which are involved in single-stranded-DNA repair, were also abundant. These results suggest a subsurface heterotrophic microbial community that primarily accesses low-quality detrital organic matter via a diverse suite of well-adapted extracellular enzymes.
IMPORTANCE Burial of organic carbon in marine and estuarine sediments represents a long-term sink for atmospheric carbon dioxide. Globally, ∼40% of organic carbon burial occurs in anoxic estuaries and deltaic systems. However, the ultimate controls on the amount of organic matter that is buried in sediments, versus oxidized into CO2, are poorly constrained. In this study, we used a combination of enzyme assays and metagenomic analysis to identify how subsurface microbial communities catalyze the first step of proteinaceous organic carbon degradation. Our results show that microbial communities in deeper sediments are adapted to access molecules characteristic of degraded organic matter, suggesting that those heterotrophs are adapted to life in the subsurface
Non-relativistic metrics from back-reacting fermions
It has recently been pointed out that under certain circumstances the
back-reaction of charged, massive Dirac fermions causes important modifications
to AdS_2 spacetimes arising as the near horizon geometry of extremal black
holes. In a WKB approximation, the modified geometry becomes a non-relativistic
Lifshitz spacetime. In three dimensions, it is known that integrating out
charged, massive fermions gives rise to gravitational and Maxwell Chern-Simons
terms. We show that Schrodinger (warped AdS_3) spacetimes exist as solutions to
a gravitational and Maxwell Chern-Simons theory with a cosmological constant.
Motivated by this, we look for warped AdS_3 or Schrodinger metrics as exact
solutions to a fully back-reacted theory containing Dirac fermions in three and
four dimensions. We work out the dynamical exponent in terms of the fermion
mass and generalize this result to arbitrary dimensions.Comment: 26 pages, v2: typos corrected, references added, minor change
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