ABSTRACT The past two decades have seen a significant advancement in the detection, classification, and understanding of exoplanets and binaries. This is due, in large part, to the increase in use of ...small-aperture telescopes (<20 cm) to survey large areas of the sky to milli-mag precision with rapid cadence. The vast majority of the planetary and binary systems studied to date consists of main-sequence or evolved objects, leading to a dearth of knowledge of properties at early times (<50 Myr). Only a dozen binaries and one candidate transiting Hot Jupiter are known among pre-main-sequence objects, yet these are the systems that can provide the best constraints on stellar formation and planetary migration models. The deficiency in the number of well characterized systems is driven by the inherent and aperiodic variability found in pre-main-sequence objects, which can mask and mimic eclipse signals. Hence, a dramatic increase in the number of young systems with high-quality observations is highly desirable to guide further theoretical developments. We have recently completed a photometric survey of three nearby (<150 pc) and young (<50 Myr) moving groups with a small-aperture telescope. While our survey reached the requisite photometric precision, the temporal coverage was insufficient to detect Hot Jupiters. Nevertheless, we discovered 346 pre-main-sequence binary candidates, including 74 high-priority objects for further study.
ABSTRACT We present the results of the optical follow-up conducted by the TOROS collaboration of the first gravitational-wave event GW150914. We conducted unfiltered CCD observations (0.35-1 m) with ...the 1.5 m telescope at Bosque Alegre starting ∼2.5 days after the alarm. Given our limited field of view (∼100 arcmin2), we targeted 14 nearby galaxies that were observable from the site and were located within the area of higher localization probability. We analyzed the observations using two independent implementations of difference-imaging algorithms, followed by a Random-Forest-based algorithm to discriminate between real and bogus transients. We did not find any bona fide transient event in the surveyed area down to a 5 limiting magnitude of r = 21.7 mag (AB). Our result is consistent with the LIGO detection of a binary black hole merger, for which no electromagnetic counterparts are expected, and with the expected rates of other astrophysical transients.
We perform an analysis of ~80000 photometric measurements for the following 10 stars hosting transiting planets: WASP-2, -4, -5, -52, Kelt-1, CoRoT-2, XO-2, TrES-1, HD 189733, GJ 436. Our analysis ...includes mainly transit lightcurves from the Exoplanet Transit Database, public photometry from the literature, and some proprietary photometry privately supplied by other authors. Half of these lightcurves were obtained by amateurs. From this photometry we derive 306 transit timing measurements, as well as improved planetary transit parameters. Additionally, for 6 of these 10 stars we present a set of radial velocity measurements obtained from the spectra stored in the HARPS, HARPS-N, and SOPHIE archives using the HARPS-TERRA pipeline. Our analysis of these TTV and RV data did not reveal significant hints of additional orbiting bodies in almost all of the cases. In the WASP-4 case, we found hints of marginally significant TTV signals having amplitude 10-20 sec, although their parameters are model-dependent and uncertain, while radial velocities did not reveal statistically significant Doppler signals.
The Safety Assurance Network Colazo, Jorge A.; Talpone, Carlos
Professional safety,
07/2009, Letnik:
54, Številka:
7
Journal Article
Recenzirano
TOYOTA IS WELL KNOWN for its benchmark production system, a complex set of tools, techniques and philosophies that yield products of the highest quality and excellent value. But not many people ...knowthat Toyota's production practices are supported by a meticulous attention to continually making work safer. The company's philosophy about workplace safety can be summarized in the words of Eiji Toyoda, one of the company's founders: "Safe work is the door to all work" (Toyota Motor Corp., 2000). This means that no kind of skilled, productive and quality work can happen effectively and efficiently if its potential impact on workers' safety was not carefully studied and addressed as a prerequisite. Similar to what the company does in terms of quality and productivity, Toyota achieves stellar ratings on industrial safety by empowering workers with tools and training that allow them to take an active role in making their workplace safer. The Safety Assurance Network One interesting safety initiative is known as the safety assurance network (SAN). SAN is a structured method that enables workers to identify, prioritize and act upon concrete workplace safety and health hazards. Drawing from the authors' experience in implementing SAN in a Toyota plant, this article describes the conceptual framework for this method and reviews the steps followed for its implementation. Toyota's work philosophy empowers workers to use and grow their skills to the fullest in designing, maintaining and improving theway inwhich theywork. Improving workplace safety is no exception to this philosophy. However, evaluating the safety hazards and developing countermeasures that would eliminate potential risks often pose particular challenges. This demands not only a good degree of worker involvement but also specialized technical and regulatory knowledge normally restricted to highly skilled safety engineers within a company's industrial safety and health (IS&H) department. As many practicing managers can attest, successfully creating a synergy between production and maintenance workers and IS&H staff is no easy task. In everyday practice, the different industrial safety stakeholders (e.g.,workers, IS&H, legal and insurance department, top management) frequently encounter barriers that seemto prevent line workers from being actively involved in safety initiatives (Harms-Ringdahl, 2003). One of those barriers is a perceived divide between two different mindsets-on the one hand, the drive for efficiency and quality of production line workers and supervisors, and on the other hand, IS&H's concern with technical effectiveness and legal compliance, all of this while strictly adhering to mandated corporate policies. SAN is one of several unique tools that Toyota uses to bridge this divide and boost the level of worker involvement. SAN is a method for identifying, classifying, prioritizing and eliminating sources of safety hazards. It is a cross-functional, team-based method that brings together line workers, production supervisors and safety engineers tomeet on site regularly to assess safety hazards. It is an observational and experiential technique that identifies hazards during the controlled execution of the actual work which can be subject to those hazards. Themethod is not proprietary to Toyota and variations can be found at use in other companies-particularly in Japan-and in industries other than the automotive sector (Masuda, Yokose, Tsunoda, et al., 2000; U.S. Department of Defense, 2000; Clemens & Pfitzer, 2006).
The Safety Assurance Network Colazo, Jorge A; Talpone, Carlos
Professional safety,
07/2009, Letnik:
54, Številka:
7
Journal Article
Recenzirano
This article describes the safety assurance network (SAN), a tool used to involve workers in the identification and elimination of potential safety hazards. The authors explain the conceptual ...framework and the steps to follow when implementing this method. SAN not only promotes improved workplace safety, it is also a powerful tool to enhance teamwork and raise workers' awareness of unsafe conditions. PUBLICATION ABSTRACT
The past two decades have seen a significant advancement in the detection, classification and understanding of exoplanets and binary star systems. The vast majority of these systems consist of stars ...on the main sequence or on the giant branch, leading to a dearth of knowledge of properties at early times (<50 Myr). Only one transiting planet candidate and a dozen eclipsing binaries are known among pre-main sequence objects, yet these are the systems that can provide the best constraints on stellar and planetary formation models. We have recently completed a photometric survey of 3 young (<50 Myr), nearby (D<150 pc) moving groups with a small-aperture instrument, nicknamed “AggieCam”. We detected 7 candidate Hot Jupiters and over 200 likely pre-main sequence binaries, which are now being followed up photometrically and spectroscopically.
The past two decades have seen a significant advancement in the detection, classification and understanding of exoplanets and binaries. This is due, in large part, to the increase in use of ...small-aperture telescopes (< 20 cm) to survey large areas of the sky to milli-mag precision with rapid cadence. The vast majority of the planetary and binary systems studied to date consist of main-sequence or evolved objects, leading to a dearth of knowledge of properties at early times (< 50 Myr). Only a dozen binaries and one candidate transiting Hot Jupiter are known among pre-main sequence objects, yet these are the systems that can provide the best constraints on stellar formation and planetary migration models. The deficiency in the number of well-characterized systems is driven by the inherent and aperiodic variability found in pre-main-sequence objects, which can mask and mimic eclipse signals. Hence, a dramatic increase in the number of young systems with high-quality observations is highly desirable to guide further theoretical developments. We have recently completed a photometric survey of 3 nearby (< 150 pc) and young (< 50 Myr) moving groups with a small aperture telescope. While our survey reached the requisite photometric precision, the temporal coverage was insufficient to detect Hot Jupiters. Nevertheless, we discovered 346 pre-main-sequence binary candidates, including 74 high-priority objects for further study.
We present the results of the optical follow-up, conducted by the TOROS collaboration, of gravitational wave events detected during the Advanced LIGO-Virgo second observing run (Nov 2016 -- Aug ...2017). Given the limited field of view (\(\sim100\arcmin\)) of our observational instrumentation we targeted galaxies within the area of high localization probability that were observable from our sites. We analyzed the observations using difference imaging, followed by a Random Forest algorithm to discriminate between real and bogus transients. For all three events that we respond to, except GW170817, we did not find any bona fide optical transient that was plausibly linked with the observed gravitational wave event. Our observations were conducted using telescopes at Estaci\'{o}n Astrof\'ısica de Bosque Alegre, Cerro Tololo Inter-American Observatory, and the Dr. Cristina V. Torres Memorial Astronomical Observatory. Our results are consistent with the LIGO-Virgo detections of a binary black hole merger (GW170104) for which no electromagnetic counterparts were expected, as well as a binary neutron star merger (GW170817) for which an optical transient was found as expected.
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