1,337 research outputs found
Eosinophilic Pleural Effusion: A Rare Manifestation of Hypereosinophilic Syndrome
Several causes of eosinophilic pleural effusions have been described with malignancy being the commonest cause. Hypereosinophilic syndrome (HES) is a rare disease and very few cases have been reported of HES presenting as eosinophilic pleural effusion (EPE). We report a case of a 26-year-old male who presented with shortness of breath. He had bilateral pleural effusions, generalized lymphadenopathy, splenomegaly, and leukocytosis with marked peripheral blood eosinophilia. The pleural fluid was exudative, with 25%–30% eosinophilis, and absence of neoplastic cells. Hypereosinophilic syndrome was diagnosed after other causes of eosinophilia were excluded. He continued to be dyspneic with persistent accumulation of eosinophilic pleural fluid, even after his peripheral eosinophil count had normalized in response to treatment. This patient represents a very unusual presentation of HES with dyspnea and pleural effusions and demonstrates that treatment based on response of peripheral eosinophil counts, as is currently recommended, may not always be clinically adequate
Neptune on tiptoes: dynamical histories that preserve the cold classical Kuiper belt
The current dynamical structure of the Kuiper belt was shaped by the orbital
evolution of the giant planets, especially Neptune, during the era following
planet formation, when the giant planets may have undergone planet-planet
scattering and/or planetesimal-driven migration. Numerical simulations of this
process, while reproducing many properties of the belt, fail to generate the
high inclinations and eccentricities observed for some objects while
maintaining the observed dynamically "cold" population. We present the first of
a three-part parameter study of how different dynamical histories of Neptune
sculpt the planetesimal disk. Here we identify which dynamical histories allow
an in situ planetesimal disk to remain dynamically cold, becoming today's cold
Kuiper belt population. We find that if Neptune undergoes a period of elevated
eccentricity and/or inclination, it secularly excites the eccentricities and
inclinations of the planetesimal disk. We demonstrate that there are several
well-defined regimes for this secular excitation, depending on the relative
timescales of Neptune's migration, the damping of Neptune's orbital inclination
and/or eccentricity, and the secular evolution of the planetesimals. We model
this secular excitation analytically in each regime, allowing for a thorough
exploration of parameter space. Neptune's eccentricity and inclination can
remain high for a limited amount of time without disrupting the cold classical
belt. In the regime of slow damping and slow migration, if Neptune is located
(for example) at 20 AU, then its eccentricity must stay below 0.18 and its
inclination below 6{\deg}.Comment: Accepted to ApJ. Update: Fixed typos in text and Appendix equations.
Published as ApJ, 746, 17
Analytical, Optimal, and Sparse Optimal Control of Traveling Wave Solutions to Reaction-Diffusion Systems
This work deals with the position control of selected patterns in
reaction-diffusion systems. Exemplarily, the Schl\"{o}gl and FitzHugh-Nagumo
model are discussed using three different approaches. First, an analytical
solution is proposed. Second, the standard optimal control procedure is
applied. The third approach extends standard optimal control to so-called
sparse optimal control that results in very localized control signals and
allows the analysis of second order optimality conditions.Comment: 22 pages, 3 figures, 2 table
Tropospheric Airborne Meteorological Data and Reporting (TAMDAR) Icing Sensor Performance during the 2003/2004 Alliance Icing Research Study (AIRS II)
NASA Langley Research Center and its research partners from the University of North Dakota (UND) and the National Center for Atmospheric Research (NCAR) participated in the AIRS II campaign from November 17 to December 17, 2003. AIRS II provided the opportunity to compare TAMDAR in situ in-flight icing condition assessments with in situ data from the UND Citation II aircraft's Rosemont system. TAMDAR is designed to provide a general warning of ice accretion and to report it directly into the Meteorological Data Communications and Reporting System (MDCRS). In addition to evaluating TAMDAR with microphysical data obtained by the Citation II, this study also compares these data to the NWS operational in-flight icing Current Icing Potential (CIP) graphic product and with the NASA Advanced Satellite Aviation-weather Products (ASAP) Icing Severity product. The CIP and ASAP graphics are also examined in this study to provide a context for the Citation II's sorties in AIRS II
Are beryllium abundances anomalous in stars with giant planets?
In this paper we present beryllium (Be) abundances in a large sample of 41
extra-solar planet host stars, and for 29 stars without any known
planetary-mass companion, spanning a large range of effective temperatures. The
Be abundances were derived through spectral synthesis done in standard Local
Thermodynamic Equilibrium, using spectra obtained with various instruments. The
results seem to confirm that overall, planet-host stars have ``normal'' Be
abundances, although a small, but not significant, difference might be present.
This result is discussed, and we show that this difference is probably not due
to any stellar ``pollution'' events. In other words, our results support the
idea that the high-metal content of planet-host stars has, overall, a
``primordial'' origin. However, we also find a small subset of planet-host
late-F and early-G dwarfs that might have higher than average Be abundances.
The reason for the offset is not clear, and might be related either to the
engulfment of planetary material, to galactic chemical evolution effects, or to
stellar-mass differences for stars of similar temperature.Comment: 15 pages, 9 figures, accepted for publication in Astronomy &
Astrophysic
Payment for Ecosystem Services from Forests
Every year between 2000 and 2010, our planet lost native forests roughly the size of Costa Rica. (FAO, 2010). This rapid deforestation has dramatically changed the chemical composition of the world's atmosphere, the level of biodiversity, and the presence of vegetation key to maintaining watershed function and preventing landslides. There has been a boom in the design of local and international policy instruments to prevent further deforestation and encourage forest growth. This paper reviews the theory and evidence surrounding forest-related Payment for Ecosystem Services (PES) schemes intended to slow and reverse deforestation. We cover the most recent work touching on a range of issues related to PES programs, including research on targeting, contract design, environmental effectiveness, challenges to program implementation, spillovers, and distributional considerations of conditional cash transfers. We also highlight areas of potential future research
Signs of oral dryness in relation to salivary flow rate, pH, buffering capacity and dry mouth complaints
<p>Abstract</p> <p>Background</p> <p>This study aimed to investigate the signs of oral dryness in relation to different salivary variables and to correlate subjective complaints of oral dryness with salivary flow rate.</p> <p>Methods</p> <p>312 unmedicated healthy individuals belonging to three age groups, (6–11, 12–17, and 18–40 years) were examined clinically for signs of oral dryness. Resting and stimulated saliva were collected to determine flow rate, pH and buffering capacity. A questionnaire was used to obtain information on subjective sensation of dry mouth.</p> <p>Results</p> <p>Dry lip and dry mucosa were present in 37.5% and 3.2% of the sample respectively. The proportion of subjects who complained of oral dryness (19%) showed a stimulated salivary flow rate significantly lower than non complainers. Dry lip was significantly related to low resting flow rate but pH and buffering capacity did not show any significant relation to dry lip. Dry mucosa was not related to any of the above mentioned parameters.</p> <p>Conclusion</p> <p>The finding that the stimulated salivary flow rate was reduced in subjects complaining of dry mouth is of great clinical relevance, since the reduction is expected to be reflected in compromising various salivary functions.</p
Seasonal melting and the formation of sedimentary rocks on Mars, with predictions for the Gale Crater mound
A model for the formation and distribution of sedimentary rocks on Mars is
proposed. The rate-limiting step is supply of liquid water from seasonal
melting of snow or ice. The model is run for a O(10^2) mbar pure CO2
atmosphere, dusty snow, and solar luminosity reduced by 23%. For these
conditions snow only melts near the equator, and only when obliquity >40
degrees, eccentricity >0.12, and perihelion occurs near equinox. These
requirements for melting are satisfied by 0.01-20% of the probability
distribution of Mars' past spin-orbit parameters. Total melt production is
sufficient to account for aqueous alteration of the sedimentary rocks. The
pattern of seasonal snowmelt is integrated over all spin-orbit parameters and
compared to the observed distribution of sedimentary rocks. The global
distribution of snowmelt has maxima in Valles Marineris, Meridiani Planum and
Gale Crater. These correspond to maxima in the sedimentary-rock distribution.
Higher pressures and especially higher temperatures lead to melting over a
broader range of spin-orbit parameters. The pattern of sedimentary rocks on
Mars is most consistent with a Mars paleoclimate that only rarely produced
enough meltwater to precipitate aqueous cements and indurate sediment. The
results suggest intermittency of snowmelt and long globally-dry intervals,
unfavorable for past life on Mars. This model makes testable predictions for
the Mars Science Laboratory rover at Gale Crater. Gale Crater is predicted to
be a hemispheric maximum for snowmelt on Mars.Comment: Submitted to Icarus. Minor changes from submitted versio
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