36,121 research outputs found
Latitude variation of recurrent fluxes in the outer solar system
Recurrent low energy (greater than or = to 0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma interaction regions, were observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2 deg S to 23 N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes at different latitudes in early 1983, distinct differences developed in the fluxes during an overall flux decrease. The flux intensities returned to higher levels in early 1984 and differences in both the recurrence frequency and flux intensity persisted into 1985, as Voyager 1 traveled to 23 AU and 25 N latitude. Intercomparison of data from the three spacecraft indicates that the flux differences are most likely due to latitudinal rather than radial or temporal variations
Decays of bottom mesons emitting tensor meson in final state using ISGW II model
In this paper, we investigate phenomenologically two-body weak decays of the
bottom mesons emitting pseudoscalar/vector meson and a tensor meson. Form
factors are obtained using the improved ISGW II model. Consequently, branching
ratios for the CKM-favored and CKM-suppressed decays are calculated.Comment: 32 pages, to be published in Phys. Rev.
A Composite Genome Approach to Identify Phylogenetically Informative Data from Next-Generation Sequencing
We have developed a novel method to rapidly obtain homologous genomic data
for phylogenetics directly from next-generation sequencing reads without the
use of a reference genome. This software, called SISRS, avoids the time
consuming steps of de novo whole genome assembly, genome-genome alignment, and
annotation. For simulations SISRS is able to identify large numbers of loci
containing variable sites with phylogenetic signal. For genomic data from apes,
SISRS identified thousands of variable sites, from which we produced an
accurate phylogeny. Finally, we used SISRS to identify phylogenetic markers
that we used to estimate the phylogeny of placental mammals. We recovered
phylogenies from multiple datasets that were consistent with previous
conflicting estimates of the relationships among mammals. SISRS is open source
and freely available at https://github.com/rachelss/SISRS.Comment: 12 pages plus36 figures, 1 supplementary table, 3 supplementary
figure
Observing Lense-Thirring Precession in Tidal Disruption Flares
When a star is tidally disrupted by a supermassive black hole (SMBH), the
streams of liberated gas form an accretion disk after their return to
pericenter. We demonstrate that Lense-Thirring precession in the spacetime
around a rotating SMBH can produce significant time evolution of the disk
angular momentum vector, due to both the periodic precession of the disk and
the nonperiodic, differential precession of the bound debris streams. Jet
precession and periodic modulation of disk luminosity are possible
consequences. The persistence of the jetted X-ray emission in the Swift
J164449.3+573451 flare suggests that the jet axis was aligned with the spin
axis of the SMBH during this event.Comment: 4 pages, 4 figures. Accepted for publication in Physical Review
Letters. Minor changes made to match proof
Solar modulation and interplanetary gradients of the galactic electrons flux, 1977 - 1984
The flux of electrons with energy from approx. 10 to 180 MeV measured with the electron telescope on the Voyager 1 and 2 spacecraft in the heliocentric radial range 1 - 22 AU between 1977 and 1984 is reported. Jovian electrons were clearly observable between 1978 and 1983 (radial range 2 - 12 AU) at energies below approx. 50 MeV. Above approx. 50 MeV the electron intensity exhibited temporal variations generally related to the 11 year modulation of protons 75 MeV. The overall magnitude of the electron intensity changes between the maximum intensity observed in 1977 and the minimum intensity in 1981 was a factor approx. 2, also comparable to that observed for 75 MeV protons. By early 1985 the electron intensity had apparently recovered to the level observed in 1977 whereas the proton intensity was still about 20% lower. A detailed interpretation of these electron variations in all energy channels depends on an accurate subtraction of background induced by energetic protons of a few 100 MeV. This subtraction is facilitated by calibration results at several energies
Effects of a Local Interstellar Magnetic Field on Voyager 1 and 2 Observations
We show that that an interstellar magnetic field can produce a north/south
asymmetry in solar wind termination shock. Using Voyager 1 and 2 measurements,
we suggest that the angle between the interstellar wind velocity and
magnetic field is . The distortion of the
shock is such that termination shock particles could stream outward along the
spiral interplanetary magnetic field connecting Voyager 1 to the shock when the
spacecraft was within of the shock. The shock distortion is larger
in the southern hemisphere, and Voyager 2 could be connected to the shock when
it is within of the shock, but with particles from the shock
streaming inward along the field. Tighter constraints on the interstellar
magnetic field should be possible when Voyager 2 crosses the shock in the next
several years.Comment: 12 pages, 5 figure
The Energy Spectrum of Jovian Electrons in Interplanetary Space
The energy spectrum of electrons with energies approx 10 to approx 180 MeV measured with the electron telescope on the Voyager 1 and 2 spacecraft in interplanetary space from 1978 to 1983 is studied. The kinetic energy of electrons is determined by double dE/dx measurements from the first two detectors (D sub 1, D sub 2) of a stack of eight solid state detectors and by the range of particle penetration into the remaining six detectors (D sub 3 to D sub 8) which are interleaved with tungsten absorbers. From 1978 to 1983 (radial range approximately 2 to a pproximately 12 AU) electrons of Jovian origin were clearly observable for electrons stopping in D(sub 3(E approximately greater than 4 MeV)) and in D(sub 4 (E approximately greater than 8 MeV)). For electrons stopping in D(sub 5(E approximately greather than 12 MeV)), the jovian flux dominated the galactic electron flux for a period of approximately one year near the encounter with Jupiter. Jovian electrons were also observed in D(sub 6(E approximately greater than 21 MeV)) but not in D(sub 7(E approximately greater than 28 MeV)). A detailed interpretation of the electron variations in all energy channels depends on an accurate subtraction of background induced by energetic protons of a few 100 MeV. This substraction is facilitated by laboratory calibration results at several energies. Further results on the differential energy spectrum of Jovian electrons and limits on the maximum detected energies will be reported
Development of Prognosis in Palliative care Study (PiPS) predictor models to improve prognostication in advanced cancer: prospective cohort study
OBJECTIVE: To develop a novel prognostic indicator for use in patients with advanced cancer that is significantly better than clinicians' estimates of survival.
DESIGN: Prospective multicentre observational cohort study. SETTING: 18 palliative care services in the UK (including hospices, hospital support teams, and community teams). PARTICIPANTS: 1018 patients with locally advanced or metastatic cancer, no longer being treated for cancer, and recently referred to palliative care services.
MAIN OUTCOME MEASURES: Performance of a composite model to predict whether patients were likely to survive for "days" (0-13 days), "weeks" (14-55 days), or "months+" (>55 days), compared with actual survival and clinicians' predictions.
RESULTS: On multivariate analysis, 11 core variables (pulse rate, general health status, mental test score, performance status, presence of anorexia, presence of any site of metastatic disease, presence of liver metastases, C reactive protein, white blood count, platelet count, and urea) independently predicted both two week and two month survival. Four variables had prognostic significance only for two week survival (dyspnoea, dysphagia, bone metastases, and alanine transaminase), and eight variables had prognostic significance only for two month survival (primary breast cancer, male genital cancer, tiredness, loss of weight, lymphocyte count, neutrophil count, alkaline phosphatase, and albumin). Separate prognostic models were created for patients without (PiPS-A) or with (PiPS-B) blood results. The area under the curve for all models varied between 0.79 and 0.86. Absolute agreement between actual survival and PiPS predictions was 57.3% (after correction for over-optimism). The median survival across the PiPS-A categories was 5, 33, and 92 days and survival across PiPS-B categories was 7, 32, and 100.5 days. All models performed as well as, or better than, clinicians' estimates of survival.
CONCLUSIONS: In patients with advanced cancer no longer being treated, a combination of clinical and laboratory variables can reliably predict two week and two month survival
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