11,157 research outputs found
Measurements of aerosol properties needed to infer backscatter characteristics in support of the NASA Doppler Lidar program
During the first year two areas of work were emphasized, analysis of aerosol data to provide improved estimates of backscatter over the Pacific ocean and development of a global model for backscatter at different wavelengths and preparation and planning for the aircraft flights of the GLOVE program. Significant progress was made in each of these areas. The analytical work is a continuation of the GAMETAG analysis, and was directed toward the development of a backscatter model for the Pacific Oceanic free troposphere. This has included a further evaluation of relationships between the optical effects at different wavelengths, a comparison of modeled optical effects at differing temporal resolutions, and an investigation of the effects of sampling on the modeled results. An initial investigation of the predictability of 9 to 10 micrometers Beta values from other data sets as well as some preliminary comparisons of the modeling results with experimental data. The comparison of the optical effects was extended to make the comparisons for different sets of time bases between 1 and 20 minutes
Measuring Fundamental Galactic Parameters with Stellar Tidal Streams and SIM PlanetQuest
Extended halo tidal streams from disrupting Milky Way satellites offer new
opportunities for gauging fundamental Galactic parameters without challenging
observations of the Galactic center. In the roughly spherical Galactic
potential tidal debris from a satellite system is largely confined to a single
plane containing the Galactic center, so accurate distances to stars in the
tidal stream can be used to gauge the Galactic center distance, R_0, given
reasonable projection of the stream orbital pole on the X_GC axis.
Alternatively, a tidal stream with orbital pole near the Y_GC axis, like the
Sagittarius stream, can be used to derive the speed of the Local Standard of
Rest (\Theta_LSR). Modest improvements in current astrometric catalogues might
allow this measurement to be made, but NASA's Space Interferometry Mission (SIM
PlanetQuest) can definitively obtain both R_0 and \Theta_LSR using tidal
streams.Comment: 8 pages, 4 figures, accepted for publication in ApJ Letters (minor
text revisions). Version with high resolution figures available at
http://www.astro.caltech.edu/~drlaw/Papers/GalaxyParameters.pd
Human Time-Frequency Acuity Beats the Fourier Uncertainty Principle
The time-frequency uncertainty principle states that the product of the
temporal and frequency extents of a signal cannot be smaller than .
We study human ability to simultaneously judge the frequency and the timing of
a sound. Our subjects often exceeded the uncertainty limit, sometimes by more
than tenfold, mostly through remarkable timing acuity. Our results establish a
lower bound for the nonlinearity and complexity of the algorithms employed by
our brains in parsing transient sounds, rule out simple "linear filter" models
of early auditory processing, and highlight timing acuity as a central feature
in auditory object processing.Comment: 4 pages, 2 figures; Accepted at PR
Assessment of distress, unmet needs, and receipt of care plans among cancer survivors in Georgia
Background: Cancer survivors have distinctive healthcare needs. The Survivorship Working Group of the Georgia Cancer Control Consortium conducted an assessment to understand the physical, psychological, practical, and spiritual needs of adult cancer survivors; patient perceptions regarding patient-provider communications; and their perceived need for services.
Methods: In 2014, a convenience sample of Georgia cancer survivors completed a paper or online survey about the presence of and distress associated with unmet physical, emotional, spiritual, and practical needs, and receipt of assistance in those areas. They were also asked about receipt of cancer treatment and survivorship care plans.
Results: Survivors were primarily female, married, White, and within 5 years of treatment. High proportions reported moderate to extreme levels of distress with depression (32.7%), anxiety (32.1%), stress (30.2%), and fear of recurrence (28.2%). Many reported no receipt of assistance in emotional needs such as changing relationships and defining a new normal and physical needs such as intimacy and body image. Fewer than half (48%) reported having received a cancer treatment summary from their physician and only 37% received a survivorship care plan. Of those who received either, 98% reported that the information was helpful.
Conclusions: Cancer survivors in Georgia who responded to the survey had unmet needs, especially related to physical and mental health. More widespread adoption of guidelines of the Commission on Cancer, including the use of distress screening tools, would assist providers in addressing identified needs directly or through referrals. A limitation is that the racial and ethnic minority participation of 20.1% is insufficient to generalize results to all cancer survivors in Georgia. Subsequent surveys would benefit from targeted approaches to reach diverse and underserved survivors
Joint Elastic Side-Scattering Lidar and Raman Lidar Measurements of Aerosol Optical Properties in South East Colorado
We describe an experiment, located in south-east Colorado, USA, that measured
aerosol optical depth profiles using two Lidar techniques. Two independent
detectors measured scattered light from a vertical UV laser beam. One detector,
located at the laser site, measured light via the inelastic Raman
backscattering process. This is a common method used in atmospheric science for
measuring aerosol optical depth profiles. The other detector, located
approximately 40km distant, viewed the laser beam from the side. This detector
featured a 3.5m2 mirror and measured elastically scattered light in a bistatic
Lidar configuration following the method used at the Pierre Auger cosmic ray
observatory. The goal of this experiment was to assess and improve methods to
measure atmospheric clarity, specifically aerosol optical depth profiles, for
cosmic ray UV fluorescence detectors that use the atmosphere as a giant
calorimeter. The experiment collected data from September 2010 to July 2011
under varying conditions of aerosol loading. We describe the instruments and
techniques and compare the aerosol optical depth profiles measured by the Raman
and bistatic Lidar detectors.Comment: 34 pages, 16 figure
Dwarf novae in the Hamburg quasar survey : rarer than expected
Aims. We report the discovery of five new dwarf novae that were spectroscopically identified in the Hamburg Quasar Survey (HQS),and discuss the properties of the sample of new dwarf novae from the HQS.
Methods. Follow-up time-resolved spectroscopy and photometry have been obtained to characterise the new systems.
Results. The orbital periods determined from analyses of the radial velocity variations and/or orbital photometric variability are Porb 105.1min or Porb 109.9min for HS 0417+7445, Porb = 114.3 ± 2.7min for HS 1016+3412, Porb = 92.66 ± 0.17 min for HS 1340+1524, Porb = 272.317 ± 0.001 min for HS 1857+7127, and Porb = 258.02 ± 0.56 min for HS 2214+2845. HS 1857+7127 is found to be partially eclipsing. In HS 2214+2845 the secondary star of spectral type M3 ± 1 is clearly detected, and we estimate the distance to the system to be d = 390 ± 40 pc. We recorded one superoutburst of HS 0417+7445, identifying the system as a SUUMatype
dwarf nova. HS 1016+3412 and HS 1340+1524 have rare outbursts, and their subtype is yet undetermined. HS 1857+7127 frequently varies in brightness and may be a ZCam-type dwarf nova. HS 2214+2845 is a UGem-type dwarf nova with a most likely cycle length of 71 d.
Conclusions. To date, 14 new dwarf novae have been identified in the HQS. The ratio of short-period (3 h)systems of this sample is 1.3, much smaller compared to the ratio of 2.7 found for all known dwarf novae. The HQS dwarf novae display typically infrequent or low-amplitude outburst activity, underlining the strength of spectroscopic selection in identifying new
CVs independently of their variability. The spectroscopic properties of short-period CVs in the HQS, newly identified and previously known, suggest that most, or possibly all of them are still evolving towards the minimum period. Their total number agrees with the predictions of population models within an order of magnitude. However, the bulk of all CVs is predicted to have evolved past the minimum period, and those systems remain unidentified. This suggests that those post-bounce systems have markedly weaker Hβ emission lines compared to the average known short-period CVs, and undergo no or extremely rare outbursts
Clinical-epidemiological features of HIV-infected patients diagnosed at age of 50 years or older
HIV/AIDS prevention and care efforts are directed to individuals of reproductive age (15–49 yrs). With the extension of sexual life of older people, they became a growing population at risk of HIV infection, usually not included in prevention strategies. In order to evaluate clinical profile of HIV/AIDS pts diagnosed at 50 yrs or older assisted in an HIV outpatient center in Buenos Aires, we retrospectively assessed clinical records of pts initiating care between Jan 1986 and Dec 2011. Age, CD4 cells and viral load (pVL) at HIV diagnosis and most recent value, opportunistic infections (OIs), co-morbidities and antiretroviral therapy (ARV) were recorded. Of 10,998 pts assisted in the 26-yr period, 495 (4.5%) were≥50 yrs old at HIV diagnosis; median annual diagnoses: 18.5 (IQR 3.3–30.3) without significant changes in the last 20 yrs. Demographics: median age 54.7 yrs (IQR 51.8–59.2, rank 50–80), 76.6% male. Risk behavior: HTX 61.4%, MSM 34.1%, others 4.4%. 55.4% of HIV diagnoses occurred during hospitalization or simultaneously with acute OIs. One third (n=176) had AIDS at diagnosis, 24% had history of STDs. HCV co-infection 5.7%, past HBV infection 28.1% and chronic HBV infection 5.1%. Median CD4 cells at HIV diagnosis: 223.5 (13.7%) (IQR 98.8–420.3), initial pVL 60,000 cp/mL (IQR 9,995.5–208,391). 69.3% of pts started ARV therapy during follow-up (FU), and the median time between diagnosis and treatment initiation was 3.4 mo (IQR 0.7–14); 56.9% of them started a non-nucleoside-based regimen (ZDV/3TC/EFV), 28.3% a PI-based regimen (ZDV/3TC/IDV) and 14.6% a nucleoside-based regimen (ZDV/ddI pre-HAART era). After a year (±6 mo), 63.8% pts achieved undetectable pVL and gained 136 CD4 cells from BSL (IQR 83–204). After 40.6 mo of FU (IQR 6.7-89.8), 66.3% are alive, 7.1% died (68.6% of HIV-related diseases) and 26.7% are lost to FU. Co-morbidities were present in 125 (25.3%), mainly hypertension, increased lipids, CVD and DBT. Among treated pts, 70.6% achieved pVL<50 cp/mL, with a median increase of CD4 cells up to 410 (22%) (IQR 281.5–563.9) from BSL. 51% (176) changed ARV therapy due to toxicity/AE: 54.5%, ARV failure: 29.5% and simplification: 14.8%. Stable HIV epidemic in older people reinforce the need of specific prevention approaches, while growing age of HIV individuals in care highlights to consider risks associated to older age. Late presentation to care needs to be specifically addressed. Response to treatment is remarkable high in this population
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