1,010 research outputs found
Implications of Pioneer-2 magnetic field models for Jupiter's decametric radio mission
The geometry and electron gyrofrequency were calculated for both the North and South feet of the Io-threaded flux tube at several altitudes as a function of sub-Io longitude for various multipole field models. The models predict a maximum surface gyrofrequency equal to the observed high frequency limit of the decameter-wave radio emission (DAM) and tend to favor a mechanism involving transverse propagation from a source in the Northern hemisphere. Calculations indicate that the beaming pattern of the emission may be determined by reflection from the ionosphere rather than by inherent beaming from the source region
A Comprehensive View of the 2006 December 13 CME: From the Sun to Interplanetary Space
The biggest halo coronal mass ejection (CME) since the Halloween storm in
2003, which occurred on 2006 December 13, is studied in terms of its solar
source and heliospheric consequences. The CME is accompanied by an X3.4 flare,
EUV dimmings and coronal waves. It generated significant space weather effects
such as an interplanetary shock, radio bursts, major solar energetic particle
(SEP) events, and a magnetic cloud (MC) detected by a fleet of spacecraft
including STEREO, ACE, Wind and Ulysses. Reconstruction of the MC with the
Grad-Shafranov (GS) method yields an axis orientation oblique to the flare
ribbons. Observations of the SEP intensities and anisotropies show that the
particles can be trapped, deflected and reaccelerated by the large-scale
transient structures. The CME-driven shock is observed at both the Earth and
Ulysses when they are separated by 74 in latitude and 117
in longitude, the largest shock extent ever detected. The ejecta seems missed
at Ulysses. The shock arrival time at Ulysses is well predicted by an MHD model
which can propagate the 1 AU data outward. The CME/shock is tracked remarkably
well from the Sun all the way to Ulysses by coronagraph images, type II
frequency drift, in situ measurements and the MHD model. These results reveal a
technique which combines MHD propagation of the solar wind and type II
emissions to predict the shock arrival time at the Earth, a significant advance
for space weather forecasting especially when in situ data are available from
the Solar Orbiter and Sentinels.Comment: 26 pages, 10 figures. 2008, ApJ, in pres
Hispanic ethnicity and survival in pediatric acute lymphocytic leukemia (all) patients in Florida
Introduction: Pediatric cancer mortality rates have drastically declined according to analyzed population-based surveillance data; however, incidences of most childhood cancers continue to rise. Recent studies have indicated an association between ethnicity/race and cancer survival. Florida's ethnically/racially diverse population and surging pediatric cancer incidence characterize the state as an ideal setting to study the association between ethnicity/race and pediatric cancer survival. Objective: To determine whether or not an association exists between Hispanic ethnicity and cancer survival in a Floridian population of pediatric patients with Acute Lymphocytic Leukemia (ALL). Methods: We will use data from participants 18 years or younger of Florida Cancer Data System (FCDS). Cox-proportional hazard regression was used to assess independent association between Hispanic ethnicity and time to death (time interval from diagnose of ALL to the last patient contact, as recorded in the database). Survival status (death or alive) was assessed at the date of last contact. Those who are alive at last contact were then censored. Results: In the unadjusted model, ethnicity was not associated with risk of death (HR= 0.87, 95% CI=0.73 - 1.04). After adjustment for sex, race, age at diagnosis, insurance status, geographic area, and immunophenotype) the results showed again no association between Hispanic ethnicity and survival (HR = 1.19, 95% CI=0.82 - 1.72). Conclusions: We found no evidence for differences in survival based on ethnic status. Potential difference in racial-survival disparities in pediatric ALL within various geographic regions might depend on Hispanic ancestries or cancer type. Further research on the topic is still deemed necessary as to clarify the nature of the association between ethnicity and cancer survival
Application of a MHD hybrid solar wind model with latitudinal dependences to Ulysses data at minimum
In a previous work, Ulysses data was analyzed to build a complete
axisymmetric MHD solution for the solar wind at minimum including rotation and
the initial flaring of the solar wind in the low corona. This model has some
problems in reproducing the values of magnetic field at 1 AU despite the
correct values of the velocity. Here, we intend to extend the previous analysis
to another type of solutions and to improve our modelling of the wind from the
solar surface to 1 AU. We compare the previous results to those obtained with a
fully helicoidal model and construct a hybrid model combining both previous
solutions, keeping the flexibility of the parent models in the appropriate
domain. From the solar surface to the Alfven, point, a three component solution
for velocity and magnetic field is used, reproducing the complex wind geometry
and the well-known flaring of the field lines observed in coronal holes. From
the Alfven radius to 1 AU and further, the hybrid model keeps the latitudinal
dependences as flexible as possible, in order to deal with the sharp variations
near the equator and we use the helicoidal solution, turning the poloidal
streamlines into radial ones. Despite the absence of the initial flaring, the
helicoidal model and the first hybrid solution suffer from the same low values
of the magnetic field at 1 AU. However, by adjusting the parameters with a
second hybrid solution, we are able to reproduce both the velocity and magnetic
profiles observed by Ulysses and a reasonable description of the low corona,
provided that a certain amount of energy deposit exists along the flow. The
present paper shows that analytical axisymmetric solutions can be constructed
to reproduce the solar structure and dynamics from 1 solar radius up to 1 AU.Comment: 12 pages, 16 figure
For which infants with viral bronchiolitis could it be deemed appropriate to use albuterol, at least on a therapeutic trial basis?
Although there is increasing evidence showing that infants with viral bronchiolitis exhibit a high degree of heterogeneity, a core uncertainty shared by many clinicians is with regard to understanding which patients are most likely to benefit from bronchodilators such as albuterol. Based on our review, we concluded that older infants with rhinovirus (RV) bronchiolitis, especially those with a nasopharyngeal microbiome dominated by Haemophilus influenzae; those affected during nonpeak months or during non-respiratory syncytial virus (RSV) predominant months; those with wheezing at presentation; those with clinical characteristics such as atopic dermatitis or a family history of asthma in a first-degree relative; and those infants infected with RSV genotypes ON1 and BA, have the greatest likelihood of benefiting from albuterol. Presently, this patient profile could serve as the basis for rational albuterol administration in patients with viral bronchiolitis, at least on a therapeutic trial basis, and it could also be the starting point for future targeted randomized clinical trials (RCTs) on the use of albuterol among a subset of infants with bronchiolitis
Messenger Observations of Mercury's Bow Shock and Magnetopause
The MESSENGER spacecraft made the first of three flybys of Mercury on January 14.2008 (1). New observations of solar wind interaction with Mercury were made with MESSENGER'S Magnetometer (MAG) (2.3) and Energetic Particle and Plasma Spectrometer (EPPS) - composed of the Energetic Particle Spectrometer (EPS) and Fast Imaging Plasma Spectrometer (FIPS) (3,4). These MESSENGER observations show that Mercury's magnetosphere has a large-scale structure that is distinctly Earth-like, but it is immersed in a comet-like cloud of planetary ions [5]. Fig. 1 provides a schematic view of the coupled solar wind - magnetosphere - neutral atmosphere - solid planet system at Mercury
Controlled reduction of photobleaching in DNA origami gold nanoparticle hybrids
The amount of information obtainable from a fluorescence-based measurement is limited by photobleaching: Irreversible photochemical reactions either render the molecules nonfluorescent or shift their absorption and/or emission spectra outside the working range. Photobleaching is evidenced as a decrease of fluorescence intensity with time, or in the case of single molecule measurements, as an abrupt, single-step interruption of the fluorescence emission that determines the end of the experiment. Reducing photobleaching is central for improving fluorescence (functional) imaging, single molecule tracking, and fluorescence-based biosensors and assays. In this single molecule study, we use DNA self-assembly to produce hybrid nanostructures containing individual fluorophores and gold nanoparticles at a controlled separation distance of 8.5 nm. By changing the nanoparticles? size we are able to systematically increase the mean number of photons emitted by the fluorophores before photobleaching.Fil: Pellegrotti, Jesica Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Acuña, Guillermo. Technische Universität Braunschweig. Institute for Physical and Theoretical Chemistry. NanoBioSciences Group; AlemaniaFil: Puchkova, Anastasiya. Technische Universität Braunschweig. Institute for Physical and Theoretical Chemistry. NanoBioSciences Group; AlemaniaFil: Holzmeister, Phil. Technische Universität Braunschweig. Institute for Physical and Theoretical Chemistry. NanoBioSciences Group; AlemaniaFil: Gietl, Andreas. Technische Universität Braunschweig. Institute for Physical and Theoretical Chemistry. NanoBioSciences Group; AlemaniaFil: Lalkens, Birka. Technische Universität Braunschweig. Institute for Physical and Theoretical Chemistry. NanoBioSciences Group; AlemaniaFil: Stefani, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Tinnefeld, Philip. Technische Universität Braunschweig. Institute for Physical and Theoretical Chemistry. NanoBioSciences Group; Alemani
Perioperative management of esophagectomy in a patient who previously underwent bilateral lung transplantation
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