3,253 research outputs found
Bayesian evidence for two companions orbiting HIP 5158
We present results of a Bayesian analysis of radial velocity (RV) data for
the star HIP 5158, confirming the presence of two companions and also
constraining their orbital parameters. Assuming Keplerian orbits, the
two-companion model is found to be e^{48} times more probable than the
one-planet model, although the orbital parameters of the second companion are
only weakly constrained. The derived orbital periods are 345.6 +/- 2.0 d and
9017.8 +/- 3180.7 d respectively, and the corresponding eccentricities are 0.54
+/- 0.04 and 0.14 +/- 0.10. The limits on planetary mass (m \sin i) and
semimajor axis are (1.44 +/- 0.14 M_{J}, 0.89 +/- 0.01 AU) and (15.04 +/- 10.55
M_{J}, 7.70 +/- 1.88 AU) respectively. Owing to large uncertainty on the mass
of the second companion, we are unable to determine whether it is a planet or a
brown dwarf. The remaining `noise' (stellar jitter) unaccounted for by the
model is 2.28 +/- 0.31 m/s. We also analysed a three-companion model, but found
it to be e^{8} times less probable than the two-companion model.Comment: 5 pages, 4 figures, 3 tables. Added a couple of figures showing the
residuals after one and two companion fits. Accepted for publication in MNRAS
Letter
Negotiation Support Systems and Software Agents in E-Business Negotiations
Experiments with negotiation software agents’ in frictionless commerce indicate potential for destructive behaviour. Most of the agents are capable of engaging in auctions and have no ability to conduct complex business negotiations. Recognizing that people and software agents operate in different although overlapping spheres we propose an environment in which negotiation and decision support systems work together with software agents in electronic negotiations. Based on our experiences with the Inspire system we constructed an environment comprising software agents, and negotiation and decision support systems. One agent monitors the process, facilitates the use of Inspire, interprets the negotiators’ activities and provides methodological advice. The architecture of this environment is based on the separation of user support functions from the autonomous software activities, separation of the support for individuals from facilitation and mediation; and scalability and the ability to provide linkages with the existing software
DNAH6 and Its Interactions with PCD Genes in Heterotaxy and Primary Ciliary Dyskinesia
Heterotaxy, a birth defect involving left-right patterning defects, and primary ciliary dyskinesia (PCD), a sinopulmonary disease with dyskinetic/immotile cilia in the airway are seemingly disparate diseases. However, they have an overlapping genetic etiology involving mutations in cilia genes, a reflection of the common requirement for motile cilia in left-right patterning and airway clearance. While PCD is a monogenic recessive disorder, heterotaxy has a more complex, largely non-monogenic etiology. In this study, we show mutations in the novel dynein gene DNAH6 can cause heterotaxy and ciliary dysfunction similar to PCD. We provide the first evidence that trans-heterozygous interactions between DNAH6 and other PCD genes potentially can cause heterotaxy. DNAH6 was initially identified as a candidate heterotaxy/PCD gene by filtering exome-sequencing data from 25 heterotaxy patients stratified by whether they have airway motile cilia defects. dnah6 morpholino knockdown in zebrafish disrupted motile cilia in Kupffer\u27s vesicle required for left-right patterning and caused heterotaxy with abnormal cardiac/gut looping. Similarly DNAH6 shRNA knockdown disrupted motile cilia in human and mouse respiratory epithelia. Notably a heterotaxy patient harboring heterozygous DNAH6 mutation was identified to also carry a rare heterozygous PCD-causing DNAI1 mutation, suggesting a DNAH6/DNAI1 trans-heterozygous interaction. Furthermore, sequencing of 149 additional heterotaxy patients showed 5 of 6 patients with heterozygous DNAH6 mutations also had heterozygous mutations in DNAH5 or other PCD genes. We functionally assayed for DNAH6/DNAH5 and DNAH6/DNAI1 trans-heterozygous interactions using subthreshold double-morpholino knockdown in zebrafish and showed this caused heterotaxy. Similarly, subthreshold siRNA knockdown of Dnah6 in heterozygous Dnah5 or Dnai1 mutant mouse respiratory epithelia disrupted motile cilia function. Together, these findings support an oligogenic disease model with broad relevance for further interrogating the genetic etiology of human ciliopathies
SHARC: Space Habitat, Assembly and Repair Center
Integrated Space Systems (ISS) has taken on the task of designing a Space Habitat, Assembly and Repair Center (SHARC) in Low Earth Orbit to meet the future needs of the space program. Our goal is to meet the general requirements given by the 1991/1992 AIAA/LORAL Team Space Design competition with an emphasis on minimizing the costs of such a design. A baseline structural configuration along with preliminary designs of the major subsystems was created. Our initial mission requirements, which were set by AIAA, were that the facility be able to: support simultaneous assembly of three major vehicles; conduct assembly operations and minimal extra vehicular activity (EVA); maintain orbit indefinitely; and assemble components 30 feet long with a 10 foot diameter in a shirtsleeve environment
On near forward high energy scattering in QCD
We consider elastic quark-quark scattering at high energy and fixed
transferred momentum. Performing factorization of soft gluon exchanges into
Wilson lines vacuum expectation values and studying their properties, we find
that the asymptotics of the scattering amplitude is controlled by the
renormalization properties of the so called cross singularities of Wilson
loops. Using this fact, we evaluate the scattering amplitude and show that its
asymptotics is determined by the properties of the matrix of
anomalous dimensions which appears after one renormalizes the cross
singularities of Wilson loops. A generalization to the case of quark-antiquark
and gluon-gluon elastic scattering is discussed.Comment: LaTeX style, 13 pages, 4 figures (included
Carboplatin and Etoposide With or Without Palifosfamide in Untreated Extensive-Stage Small-Cell Lung Cancer: A Multicenter, Adaptive, Randomized Phase III Study (MATISSE)
Purpose
To evaluate the efficacy of the addition of palifosfamide to carboplatin and etoposide in extensive stage (ES) small-cell lung cancer (SCLC).
Patients and Methods
MATISSE was a randomized, open-label, adaptive phase III study. Previously untreated patients with ES SCLC were randomly assigned in a 1:1 fashion to receive carboplatin at area under the serum concentration-time curve 5 on day 1 plus etoposide 100 mg/m2 per day on days 1 to 3 every 21 days (CE) or carboplatin at area under the serum concentration-time curve 4 on day 1 plus etoposide 100 mg/m2 per day plus palifosfamide 130 mg/m2 per day on days 1 to 3 every 21 days (PaCE). The primary end point was overall survival.
Results
In all, 188 patients were enrolled; 94 patients received CE and 94 patients received PaCE. The median age on both arms was 61 years. Six cycles of chemotherapy were completed on both arms of the study by approximately 50% of the patients. Serious adverse events were documented and did not differ significantly between patients receiving PaCE and those receiving CE. Median overall survival was similar between both arms with 10.03 months on PaCE and 10.37 months on CE (P = .096).
Conclusion
The addition of palifosfamide to CE failed to improve survival in ES SCLC
Odd properly colored cycles in edge-colored graphs
It is well-known that an undirected graph has no odd cycle if and only if it
is bipartite. A less obvious, but similar result holds for directed graphs: a
strongly connected digraph has no odd cycle if and only if it is bipartite. Can
this result be further generalized to more general graphs such as edge-colored
graphs? In this paper, we study this problem and show how to decide if there
exists an odd properly colored cycle in a given edge-colored graph. As a
by-product, we show how to detect if there is a perfect matching in a graph
with even (or odd) number of edges in a given edge set
Directed follow-up strategy of low-cadence photometric surveys in Search of transiting exoplanets - I. Bayesian approach for adaptive scheduling
We propose a novel approach to utilize low-cadence photometric surveys for
exoplanetary transit search. Even if transits are undetectable in the survey
database alone, it can still be useful for finding preferred times for directed
follow-up observations that will maximize the chances to detect transits. We
demonstrate the approach through a few simulated cases. These simulations are
based on the Hipparcos Epoch Photometry data base, and the transiting planets
whose transits were already detected there. In principle, the approach we
propose will be suitable for the directed follow-up of the photometry from the
planned Gaia mission, and it can hopefully significantly increase the yield of
exoplanetary transits detected, thanks to Gaia.Comment: 11 pages, 11 figures,accepted for publication in MNRA
Acyclicity in edge-colored graphs
A walk in edge-colored graphs is called properly colored (PC) if every
pair of consecutive edges in is of different color. We introduce and study
five types of PC acyclicity in edge-colored graphs such that graphs of PC
acyclicity of type is a proper superset of graphs of acyclicity of type
, The first three types are equivalent to the absence of PC
cycles, PC trails, and PC walks, respectively. While graphs of types 1, 2 and 3
can be recognized in polynomial time, the problem of recognizing graphs of type
4 is, somewhat surprisingly, NP-hard even for 2-edge-colored graphs (i.e., when
only two colors are used). The same problem with respect to type 5 is
polynomial-time solvable for all edge-colored graphs. Using the five types, we
investigate the border between intractability and tractability for the problems
of finding the maximum number of internally vertex disjoint PC paths between
two vertices and the minimum number of vertices to meet all PC paths between
two vertices
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