Constraining the period of the ringed secondary companion to the young star J1407 with photographic plates

Context. The 16 Myr old star 1SWASP J140747.93-394542.6 (V1400 Cen) underwent a series of complex eclipses in May 2007, interpreted as the transit of a giant Hill sphere filling debris ring system around a secondary companion, J1407b. No other eclipses have since been detected, although other measurements have constrained but not uniquely determined the orbital period of J1407b. Finding another eclipse towards J1407 will help determine the orbital period of the system, the geometry of the proposed ring system and enable planning of further observations to characterize the material within these putative rings. Aims. We carry out a search for other eclipses in photometric data of J1407 with the aim of constraining the orbital period of J1407b. Methods. We present photometry from archival photographic plates from the Harvard DASCH survey, and Bamberg and Sonneberg Observatories, in order to place additional constraints on the orbital period of J1407b by searching for other dimming and eclipse events. Using a visual inspection of all 387 plates and a period-folding algorithm we performed a search for other eclipses in these data sets. Results. We find no other deep eclipses in the data spanning from 1890 to 1990, nor in recent time-series photometry from 2012-2018. Conclusions. We rule out a large fraction of putative orbital periods for J1407b from 5 to 20 years. These limits are still marginally consistent with a large Hill sphere filling ring system surrounding a brown dwarf companion in a bound elliptical orbit about J1407. Issues with the stability of any rings combined with the lack of detection of another eclipse, suggests that J1407b may not be bound to J1407.Comment: 8 pages, 3 tables, 4 figures, accepted for publication in A&A. LaTeX files of the paper, scripts for the figures, and a minimal working FPA can be found under https://github.com/robinmentel/Constraining-Period

Laue diffraction lenses for astrophysics: From theory to experiments

Based on the laws of X-ray diffraction in crystals, Laue lenses offer a promising way to achieve the sensitivity and angular resolution leap required for the next generation of hard X-ray and gamma-ray telescopes. The present paper describes the instrumental responses of Laue diffraction lenses designed for nuclear astrophysics. Different possible geometries are discussed, as well as the corresponding spectral and imaging capabilities. These theoretical predictions are then compared with Monte-Carlo simulations and experimental results (ground and stratospheric observations from the CLAIRE project)

Comparative safety and health care expenditures among patients with chronic myeloid leukemia initiating first-line imatinib, dasatinib, or nilotinib

PURPOSE Tyrosine kinase inhibitors (TKIs) have dramatically improved survival for patients with chronic myeloid leukemia (CML). No overall survival differences were observed between patients initiating first- and second-generation TKIs in trials; however, real-world safety and cost outcomes are unclear. We evaluated comparative safety and health care expenditures between first-line imatinib, dasatinib, and nilotinib among patients with CML. PATIENTS AND METHODS Eligible patients had one or more fills for imatinib, dasatinib, or nilotinib in the MarketScan Commercial and Medicare Supplemental databases between January 1, 2011, and December 31, 2016 (earliest fill is the index date), 6 months pre-index continuous enrollment, CML diagnosis, and no TKI use in the pre-index period. Hospitalizations or emergency department visits (safety events) were compared across treatment groups using propensity-score-weighted 1-year relative risks (RRs) and subdistribution hazard ratios (HRs). Inflation-adjusted annual health care expenditures were compared using quantile regression. RESULTS Eligible patients included 1,417 receiving imatinib, 1,067 receiving dasatinib, and 647 receiving nilotinib. The 1-year risk of safety events was high: imatinib, 37%; dasatinib, 44%; and nilotinib, 40%, with higher risks among patients receiving dasatinib (RR, 1.17; 95% CI, 1.06 to 1.30) and nilotinib (RR, 1.07; 95% CI, 0.93 to 1.23) compared with those receiving imatinib. Over a median of 1.7 years, the cumulative incidence of safety events was higher among patients receiving dasatinib (HR, 1.23; 95% CI, 1.10 to 1.38) and nilotinib (HR, 1.08; 95% CI, 0.95 to 1.24) than among those receiving imatinib. One-year health care expenditures were high (median, $125,987) and were significantly higher among patients initiating second-generation TKIs compared with those receiving imatinib (difference in medians: dasatinib v imatinib,$22,393; 95% CI, $17,068 to$27,718; nilotinib v imatinib, $19,463; 95$14,689 to $24,236). CONCLUSION Patients receiving imatinib had the lowest risk of hospitalization or emergency department visits and 1-year health care expenditures. Given a lack of significant differences in overall survival, imatinib may represent the ideal first-line therapy for patients, on average

Slewing Mirror Telescope and the Data-Acquisition System for the UFFO-Pathfinder

The Ultra-Fast Flash Observatory (UFFO) aims to detect the earliest moment of Gamma-Ray Bursts (GRBs) which is not well known, resulting into the enhancement of GRB mechanism understanding. The pathfinder mission was proposed to be a scaled-down version of UFFO, and only contains the UFFO Burst Alert & Trigger Telescope (UBAT) measuring the X-ray/gamma-ray with the wide-field of view and the Slewing Mirror Telescope (SMT) with a rapid-response for the UV/optical photons. Once the UBAT detects a GRB candidate with the position accuracy of 10 arcmin, the SMT steers the UV/optical photons from the candidate to the telescope by the fast rotatable mirror and provides the early UV/optical photons measurements with 4 arcsec accuracy. The SMT has a modified Ritchey-Chrètien telescope with the aperture size of 10 cm diameter including the rotatable mirror and the image readout by the intensified charge-coupled device. There is a key board called the UFFO Data Acquisition system (UDAQ) that manages the communication of each telescope and also of the satellite and the UFFO overall operation. This pathfinder is designed and built within the limited size and weight of  ~20 kg and the low power consumption up to  ~30 W. We will discuss the design and performance of the UFFO-pathfinder, and its integration to the Lomonosov satellite

Pulse combustion: The quantification of characteristic times

Measurements of the total ignition delay time in a pulse combustor have been made for several chemical kinetic ignition delay times and several fluid dynamic mixing times. These measured total ignition delay times are compared with calculated values of the characteristic time for mixing and with calculated values for the homogeneous ignition delay time. A chemical kinetic model was used to calculate the homogeneous chemical kinetic ignition delay time for conditions typical of an operating pulse combustor. Similarly, a fluid dynamic mixing model was used to estimate characteristic times for a transient jet of cold reactants to mix with an ambient environment of hot products to an ignition temperature. These calculated time scales compared well with measured values in both trend and magnitude. It has also been shown that a simple sum of the characteristic mixing times and chemical kinetics times provides a good first-order approximation to the total ignition delay time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28736/1/0000563.pd

Design and implementation of electronics and data acquisition system for Ultra-Fast Flash Observatory

The Ultra-Fast Flash Observatory (UFFO) Pathfinder for Gamma-Ray Bursts (GRBs) consists of two telescopes. The UFFO Burst Alert & Trigger Telescope (UBAT) handles the detection and localization of GRBs, and the Slewing Mirror Telescope (SMT) conducts the measurement of the UV/optical afterglow. UBAT is equipped with an X-ray detector, analog and digital signal readout electronics that detects X-rays from GRBs and determines the location. SMT is equipped with a stepping motor and the associated electronics to rotate the slewing mirror targeting the GRBs identified by UBAT. First the slewing mirror points to a GRB, then SMT obtains the optical image of the GRB using the intensified CCD and its readout electronics. The UFFO Data Acquisition system (UDAQ) is responsible for the overall function and operation of the observatory and the communication with the satellite main processor. In this paper we present the design and implementation of the electronics of UBAT and SMT as well as the architecture and implementation of UDAQ

Development of Motorized Slewing Mirror Stage for the UFFO Project

The Ultra-Fast Flash Observatory (UFFO) is a space observatory for optical follow-ups of gamma ray bursts (GRBs), aiming to explore the first 60 seconds of GRBs optical emission. UFFO is utilized to catch early optical emissions from GRBs within few sec after trigger using a Gimbal mirror which redirects the optical path rather than slewing entire spacecraft. We have developed a 15 cm two-axis Gimbal mirror stage for the UFFO-Pathfinder which is going to be on board the Lomonosov satellite which is to be launched in 2013. The stage is designed for fast and accurate motion with given budgets of 3 kg of mass and 3 Watt of power. By employing stepping motors, the slewing mirror can rotate faster than 15 deg/sec so that objects in the UFFO coverage (60 deg × 60 deg) can be targeted in ~1 sec. The obtained targeting resolution is better 2 arcmin using a close-loop control with high precision rotary encoder. In this presentation, we will discuss details of design, manufacturing, space qualification tests, as well as performance tests

Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results