725 research outputs found

    A Gluing Construction Regarding Point Particles in General Relativity

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    We develop a gluing construction which adds scaled and truncated asymptotically Euclidean solutions of the Einstein constraint equations to compact solutions with potentially non-trivial cosmological constants. The result is a one-parameter family of initial data which has ordinary and scaled "point-particle" limits analogous to those of Gralla and Wald ("A rigorous derivation of gravitational self-force," Class. Quantum Grav. 2008). In particular, we produce examples of initial data which generalize Schwarzschild - de Sitter initial data and gluing theorems of IMP-type

    Comparison of an extended-release formulation of granisetron (APF530) versus palonosetron for the prevention of chemotherapy-induced nausea and vomiting associated with moderately or highly emetogenic chemotherapy: results of a prospective, randomized, double-blind, noninferiority phase 3 trial

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    PURPOSE: Subcutaneous APF530 provides controlled sustained release of granisetron to prevent acute (0-24 h) and delayed (24-120 h) chemotherapy-induced nausea and vomiting (CINV). This randomized, double-blind phase 3 trial compared APF530 and palonosetron in preventing acute and delayed CINV after moderately (MEC) or highly emetogenic chemotherapy (HEC). METHODS: Patients receiving single-day MEC or HEC received single-dose APF530 250 or 500 mg subcutaneously (SC) (granisetron 5 or 10 mg) or intravenous palonosetron 0.25 mg. Primary objectives were to establish APF530 noninferiority to palonosetron for preventing acute CINV following MEC or HEC and delayed CINV following MEC and to determine APF530 superiority to palonosetron for preventing delayed CINV following HEC. The primary efficacy end point was complete response (CR [using CI difference for APF530 - palonosetron]). A lower confidence bound greater than -15 % indicated noninferiority. RESULTS: In the modified intent-to-treat population (MEC = 634; HEC = 707), both APF530 doses were noninferior to palonosetron in preventing acute CINV after MEC (CRs 74.8 % [-9.8, 9.3] and 76.9 % [-7.5, 11.4], respectively, vs. 75.0 % palonosetron) and after HEC (CRs 77.7 % [-11.5, 5.5] and 81.3 % [-7.7, 8.7], respectively, vs. 80.7 % palonosetron). APF530 500 mg was noninferior to palonosetron in preventing delayed CINV after MEC (CR 58.5 % [-9.5, 12.1] vs. 57.2 % palonosetron) but not superior in preventing delayed CINV after HEC. Adverse events were generally mild and unrelated to treatment, the most common (excluding injection-site reactions) being constipation. CONCLUSIONS: A single subcutaneous APF530 injection offers a convenient alternative to palonosetron for preventing acute and delayed CINV after MEC or HEC

    Electromagnetic self-forces and generalized Killing fields

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    Building upon previous results in scalar field theory, a formalism is developed that uses generalized Killing fields to understand the behavior of extended charges interacting with their own electromagnetic fields. New notions of effective linear and angular momenta are identified, and their evolution equations are derived exactly in arbitrary (but fixed) curved spacetimes. A slightly modified form of the Detweiler-Whiting axiom that a charge's motion should only be influenced by the so-called "regular" component of its self-field is shown to follow very easily. It is exact in some interesting cases, and approximate in most others. Explicit equations describing the center-of-mass motion, spin angular momentum, and changes in mass of a small charge are also derived in a particular limit. The chosen approximations -- although standard -- incorporate dipole and spin forces that do not appear in the traditional Abraham-Lorentz-Dirac or Dewitt-Brehme equations. They have, however, been previously identified in the test body limit.Comment: 20 pages, minor typos correcte

    The Atacama Cosmology Telescope: CO(J = 3 - 2) mapping and lens modeling of an ACT-selected dusty star-forming galaxy

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    We report Northern Extended Millimeter Array (NOEMA) CO(J=32J = 3 - 2) observations of the dusty star-forming galaxy ACT-S\,J020941+001557 at z=2.5528z = 2.5528, which was detected as an unresolved source in the Atacama Cosmology Telescope (ACT) equatorial survey. Our spatially resolved spectral line data support the derivation of a gravitational lens model from 37 independent velocity channel maps using a pixel-based algorithm, from which we infer a velocity-dependent magnification factor μ722\mu \approx 7-22 with a luminosity-weighted mean \left\approx 13. The resulting source-plane reconstruction is consistent with a rotating disk, although other scenarios cannot be ruled out by our data. After correction for lensing, we derive a line luminosity LCO(32)=(5.53±0.69)×1010Kkms1pc2L^{\prime}_{\rm CO(3-2)}= (5.53\pm 0.69) \times 10^{10}\,{\rm \,K\,km\,s^{-1}\,pc^{2}}, a cold gas mass Mgas=(3.86±0.33)×1010MM_{{\rm gas}}= (3.86 \pm 0.33) \times 10^{10}\,M_{\odot}, a dynamical mass Mdynsin2i=3.91.5+1.8×1010MM_{\rm dyn}\,{\rm sin}^2\,i = 3.9^{+1.8}_{-1.5} \times 10^{10}\,M_{\odot}, and a gas mass fraction fgascsc2i=1.00.4+0.8f_{\rm gas}\,{\rm csc}^2\,i = 1.0^{+0.8}_{-0.4}. The line brightness temperature ratio of r3,11.6r_{3,1}\approx 1.6 relative to a Green Bank Telescope CO(J=10J=1-0) detection may be elevated by a combination of external heating of molecular clouds, differential lensing, and/or pointing errors.Comment: 8 pages, 5 figures, accepted to Ap

    A new concurrent chemotherapy with vinorelbine and mitomycin C in combination with radiotherapy in patients with locally advanced squamous cell carcinoma of the head and neck

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    Objective: The purpose of this pilot study was to evaluate the feasibility and toxicity of concurrent chemotherapy with vinorelbine and mitomycin C in combination with accelerated radiotherapy (RT) in patients with locally advanced cancer of the head and neck. Patients and Methods: Between January 2003 and March 2004, 15 patients with T4/N2-3 squamous cell carcinoma (12/15) and with N3 cervical lymph node metastases of carcinoma of unknown primary (3/15) were treated with chemotherapy and simultaneous accelerated RT. Results: 11 patients completed therapy without interruption or dose reduction. Grade 3 - 4 acute mucosal toxicity was observed in 9/15 patients, grade 4 hematologic toxicity in 6/15 patients. At a median follow-up of 7.5 months, 2 patients have died of intercurrent disease, 2 patients have experienced local relapse; 5 patients are alive with no evidence of disease at the primary tumor site. Discussion: The described regimen is highly effective, but led to remarkable side effects

    Average Heating Rate of Hot Atmospheres in Distant Clusters by Radio AGN: Evidence for Continuous AGN Heating

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    We examine atmospheric heating by radio active galactic nuclei (AGN) in distant X-ray clusters by cross correlating clusters selected from the 400 Square Degree (400SD) X-ray Cluster survey with radio sources in the NRAO VLA Sky Survey. Roughly 30% of the clusters show radio emission above a flux threshold of 3 mJy within a projected radius of 250 kpc. The radio emission is presumably associated with the brightest cluster galaxy. The mechanical jet power for each radio source was determined using scaling relations between radio power and cavity (mechanical) power determined for nearby clusters, groups, and galaxies with hot atmospheres containing X-ray cavities. The average jet power of the central radio AGN is approximately 2×10442\times 10^{44}\ergs. We find no significant correlation between radio power, hence mechanical jet power, and the X-ray luminosities of clusters in the redshift range 0.1 -- 0.6. This implies that the mechanical heating rate per particle is higher in lower mass, lower X-ray luminosity clusters. The jet power averaged over the sample corresponds to an atmospheric heating of approximately 0.2 keV per particle within R500_{500}. Assuming the current AGN heating rate does not evolve but remains constant to redshifts of 2, the heating rate per particle would rise by a factor of two. We find that the energy injected from radio AGN contribute substantially to the excess entropy in hot atmospheres needed to break self-similarity in cluster scaling relations. The detection frequency of radio AGN is inconsistent with the presence of strong cooling flows in 400SD clusters, but does not exclude weak cooling flows. It is unclear whether central AGN in 400SD clusters are maintained by feedback at the base of a cooling flow. Atmospheric heating by radio AGN may retard the development of strong cooling flows at early epochs.Comment: ApJ in pres

    Mechanics of extended masses in general relativity

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    The "external" or "bulk" motion of extended bodies is studied in general relativity. Compact material objects of essentially arbitrary shape, spin, internal composition, and velocity are allowed as long as there is no direct (non-gravitational) contact with other sources of stress-energy. Physically reasonable linear and angular momenta are proposed for such bodies and exact equations describing their evolution are derived. Changes in the momenta depend on a certain "effective metric" that is closely related to a non-perturbative generalization of the Detweiler-Whiting R-field originally introduced in the self-force literature. If the effective metric inside a self-gravitating body can be adequately approximated by an appropriate power series, the instantaneous gravitational force and torque exerted on it is shown to be identical to the force and torque exerted on an appropriate test body moving in the effective metric. This result holds to all multipole orders. The only instantaneous effect of a body's self-field is to finitely renormalize the "bare" multipole moments of its stress-energy tensor. The MiSaTaQuWa expression for the gravitational self-force is recovered as a simple application. A gravitational self-torque is obtained as well. Lastly, it is shown that the effective metric in which objects appear to move is approximately a solution to the vacuum Einstein equation if the physical metric is an approximate solution to Einstein's equation linearized about a vacuum background.Comment: 39 pages, 2 figures; fixed equation satisfied by the Green function used to construct the effective metri

    Programming gene expression with combinatorial promoters

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    Promoters control the expression of genes in response to one or more transcription factors (TFs). The architecture of a promoter is the arrangement and type of binding sites within it. To understand natural genetic circuits and to design promoters for synthetic biology, it is essential to understand the relationship between promoter function and architecture. We constructed a combinatorial library of random promoter architectures. We characterized 288 promoters in Escherichia coli, each containing up to three inputs from four different TFs. The library design allowed for multiple −10 and −35 boxes, and we observed varied promoter strength over five decades. To further analyze the functional repertoire, we defined a representation of promoter function in terms of regulatory range, logic type, and symmetry. Using these results, we identified heuristic rules for programming gene expression with combinatorial promoters

    The Atacama Cosmology Telescope: The LABOCA/ACT Survey of Clusters at All Redshifts

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    We present a multi-wavelength analysis of eleven Sunyaev Zel'dovich effect (SZE)-selected galaxy clusters (ten with new data) from the Atacama Cosmology Telescope (ACT) southern survey. We have obtained new imaging from the Large APEX Bolometer Camera (345GHz; LABOCA) on the Atacama Pathfinder EXperiment (APEX) telescope, the Australia Telescope Compact Array (2.1GHz; ATCA), and the Spectral and Photometric Imaging Receiver (250, 350, and 500μm500\,\rm\mu m; SPIRE) on the Herschel Space Observatory. Spatially-resolved 345GHz SZE increments with integrated S/N > 5 are found in six clusters. We compute 2.1GHz number counts as a function of cluster-centric radius and find significant enhancements in the counts of bright sources at projected radii θ<θ2500\theta < \theta_{2500}. By extrapolating in frequency, we predict that the combined signals from 2.1GHz-selected radio sources and 345GHz-selected SMGs contaminate the 148GHz SZE decrement signal by ~5% and the 345GHz SZE increment by ~18%. After removing radio source and SMG emission from the SZE signals, we use ACT, LABOCA, and (in some cases) new Herschel SPIRE imaging to place constraints on the clusters' peculiar velocities. The sample's average peculiar velocity relative to the cosmic microwave background is 153±383kms1153\pm 383\,\rm km\,s^{-1}.Comment: 19 pages, 11 figures, Accepted for Publication in The Astrophysical Journa
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