1,109 research outputs found
Dengue Risk among Visitors to Hawaii during an Outbreak
Despite the high rates of dengue in many tropical destinations frequented by tourists, limited information is available on the risk for infection among short-term visitors. We retrospectively surveyed 4,000 persons who arrived in Hawaii during the peak of the 2001–2002 dengue outbreak and collected follow-up serologic test results for those reporting denguelike illness. Of 3,064 visitors who responded, 94 (3%) experienced a denguelike illness either during their trip or within 14 days of departure; 34 of these persons were seen by a physician, and 2 were hospitalized. Twenty-seven visitors with denguelike illness provided a serum specimen; all specimens were negative for anti-dengue immunoglobulin G antibodies. The point estimate of dengue incidence was zero infections per 358 person-days of exposure with an upper 95% confidence limit of 3.0 cases per person-year. Thus, the risk for dengue infection for visitors to Hawaii during the outbreak was low
Prevalence and Risk Factors for Methicillin-Resistant Staphylococcus aureus in an HIV-Positive Cohort
Background: Persons living with HIV (PLWH) are disproportionately burdened with methicillin-resistant Staphylococcus aureus (MRSA). Our objective was to evaluate prevalence and risks for MRSA colonization in PLWH. Methods: Adults were recruited from Johns Hopkins University AIDS Service in Baltimore, Maryland. A risk questionnaire and specimen collection from anatomic sites with culture susceptibility and genotyping were completed. Generalized estimating equation modeling identified MRSA colonization risk factors. Results: Of 500 participants,mostwere black (69%), on antiretroviral therapy (ART) (87%),with undetectable viral loads (73.4%). Median CD4 count was 487 cells/mm3 (interquartile range, 316-676.5 cells/mm3). MRSA prevalence was 15.4%, predominantly from the nares (59.7%). Forty percent were nares negative but were colonized elsewhere. Lower odds for colonizationwere associatedwith recent sexual activity (adjusted odds ratio [AOR]¼0.84, P$75,000; AOR ¼ 2.68, P \u3c .001), recent hospitalization (AOR ¼ 1.54, P \u3c .001), incarceration (AOR ¼ 1.55,
Prevalence and Risk Factors for Methicillin-Resistant Staphylococcus aureus in an HIV-Positive Cohort
Background: Persons living with HIV (PLWH) are disproportionately burdened with methicillin-resistant Staphylococcus aureus (MRSA). Our objective was to evaluate prevalence and risks for MRSA colonization in PLWH. Methods: Adults were recruited from Johns Hopkins University AIDS Service in Baltimore, Maryland. A risk questionnaire and specimen collection from anatomic sites with culture susceptibility and genotyping were completed. Generalized estimating equation modeling identified MRSA colonization risk factors. Results: Of 500 participants,mostwere black (69%), on antiretroviral therapy (ART) (87%),with undetectable viral loads (73.4%). Median CD4 count was 487 cells/mm3 (interquartile range, 316-676.5 cells/mm3). MRSA prevalence was 15.4%, predominantly from the nares (59.7%). Forty percent were nares negative but were colonized elsewhere. Lower odds for colonizationwere associatedwith recent sexual activity (adjusted odds ratio [AOR]¼0.84, P$75,000; AOR ¼ 2.68, P \u3c .001), recent hospitalization (AOR ¼ 1.54, P \u3c .001), incarceration (AOR ¼ 1.55,
Bolocam Survey for 1.1 mm Dust Continuum Emission in the c2d Legacy Clouds. II. Ophiuchus
We present a large-scale millimeter continuum map of the Ophiuchus molecular
cloud. Nearly 11 square degrees, including all of the area in the cloud with
visual extinction more than 3 magnitudes, was mapped at 1.1 mm with Bolocam on
the Caltech Submillimeter Observatory (CSO). By design, the map also covers the
region mapped in the infrared with the Spitzer Space Telescope. We detect 44
definite sources, and a few likely sources are also seen along a filament in
the eastern streamer. The map indicates that dense cores in Ophiuchus are very
clustered and often found in filaments within the cloud. Most sources are
round, as measured at the half power point, but elongated when measured at
lower contour levels, suggesting spherical sources lying within filaments. The
masses, for an assumed dust temperature of 10 K, range from 0.24 to 3.9 solar
masses, with a mean value of 0.96 solar masses. The total mass in distinct
cores is 42 solar masses, 0.5 to 2% of the total cloud mass, and the total mass
above 4 sigma is about 80 solar masses. The mean densities in the cores are
quite high, with an average of 1.6 x 10^6 per cc, suggesting short free-fall
times. The core mass distribution can be fitted with a power law with slope of
2.1 plus or minus 0.3 for M>0.5 solar masses, similar to that found in other
regions, but slightly shallower than that of some determinations of the local
IMF. In agreement with previous studies, our survey shows that dense cores
account for a very small fraction of the cloud volume and total mass. They are
nearly all confined to regions with visual extinction at least 9 mag, a lower
threshold than found previously.Comment: 47 pages, 16 figures, accepted for Ap
Exploring the links between secondary metabolites and leaf spectral reflectance in a diverse genus of Amazonian trees
Plant defense chemistry is often hypothesized to drive ecological and evolutionary success in diverse tropical forests, yet detailed characterizations of plant secondary metabolites in tropical plants are logistically challenging. Here, we explore a new integrative approach that combines visible-to-shortwave infrared (VSWIR) spectral reflectance data with detailed plant metabolomics data from 19 Protium (Burseraceae) tree species. Building on the discovery that different Protium species have unique chemistries yet share many secondary metabolites, we devised a method to test for associations between metabolites and VSWIR spectral data. Given species-level variation in metabolite abundance, we correlated the concentration of particular chemicals with the reflectance of the spectral bands in a wavelength band per secondary metabolite matrix. We included 45 metabolites that were shared by at least 5 Protium species and correlated their per-species foliar abundances against each one of 210 wavelength bands of field-measured VSWIR spectra. Finally, we tested whether classes of similar metabolites showed similar relationships with spectral patterns. We found that many secondary metabolites yielded strong correlations with VSWIR spectra of Protium. Furthermore, important Protium metabolite classes such as procyanidins (condensed tannins) and phytosterols were grouped together in a hierarchical clustering analysis (Ward’s algorithm), confirming similarity in their associations with plant spectral patterns. We also found a significant correlation in the phenolics content between juvenile and canopy trees of the same species, suggesting that species-level variation in defense chemistry is consistent across life stages and geographic distribution. We conclude that the integration of spectral and metabolic approaches could represent a powerful and economical method to characterize important aspects of tropical plant defense chemistry
Young Stellar Objects in the Gould Belt
We present the full catalog of Young Stellar Objects (YSOs) identified in the
18 molecular clouds surveyed by the Spitzer Space Telescope "cores to disks"
(c2d) and "Gould Belt" (GB) Legacy surveys. Using standard techniques developed
by the c2d project, we identify 3239 candidate YSOs in the 18 clouds, 2966 of
which survive visual inspection and form our final catalog of YSOs in the Gould
Belt. We compile extinction corrected SEDs for all 2966 YSOs and calculate and
tabulate the infrared spectral index, bolometric luminosity, and bolometric
temperature for each object. We find that 326 (11%), 210 (7%), 1248 (42%), and
1182 (40%) are classified as Class 0+I, Flat-spectrum, Class II, and Class III,
respectively, and show that the Class III sample suffers from an overall
contamination rate by background AGB stars between 25% and 90%. Adopting
standard assumptions, we derive durations of 0.40-0.78 Myr for Class 0+I YSOs
and 0.26-0.50 Myr for Flat-spectrum YSOs, where the ranges encompass
uncertainties in the adopted assumptions. Including information from
(sub)millimeter wavelengths, one-third of the Class 0+I sample is classified as
Class 0, leading to durations of 0.13-0.26 Myr (Class 0) and 0.27-0.52 Myr
(Class I). We revisit infrared color-color diagrams used in the literature to
classify YSOs and propose minor revisions to classification boundaries in these
diagrams. Finally, we show that the bolometric temperature is a poor
discriminator between Class II and Class III YSOs.Comment: Accepted for publication in ApJS. 29 pages, 11 figures, 14 tables, 4
appendices. Full versions of data tables (to be published in machine-readable
format by ApJS) available at the end of the latex source cod
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