Sidereal frequency generator Patent

System generating sidereal frequency signals from signals of standard solar frequency without use of mixing operations or feedback loop

TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and WASP-1b

We present four new light curves of transiting exoplanets WASP-1b and HAT-P-20b, observed within the TASTE (The Asiago Search for Transit timing variations of Exoplanets) project. We re-analyzed light curves from the literature in a homogeneous way, calculating a refined ephemeris and orbital-physical parameters for both objects. WASP-1b does not show any significant Transit Timing Variation signal at the 120 s-level. As for HAT-P-20b, we detected a deviation from our re-estimated linear ephemeris that could be ascribed to the presence of a perturber or, more probably, to a previously unnoticed high level of stellar activity. The rotational period of HAT-P-20 A we obtained from archival data (P_rot ~ 14.5 days), combined with its optical variability and strong emission of CaII H&K lines, is consistent with a young stellar age (< 1 Gyr) and support the hypothesis that stellar activity may be responsible of the measured deviations of the transit times.Comment: 7 pages, 4 figures, 3 tables, accepted to Astronomische Nachrichte

Variable stars in one open cluster within the Kepler/K2-Campaign-5 field: M 67 (NGC 2682)

In this paper we continue the release of high-level data products from the multiyear photometric survey collected at the 67/92 cm Schmidt Telescope in Asiago. The primary goal of the survey is to discover and to characterise variable objects and exoplanetary transits in four fields containing five nearby open clusters spanning a broad range of ages. This second paper releases a photometric catalogue, in five photometric bands, of the Solar-age, Solar-metallicity open cluster M 67 (NGC 2682). Proper motions are derived comparing the positions observed in 2013 at the Asiago's Schmidt Telescope with those extracted from [email protected] MPG/ESO images in 2000. We also analyse the variable sources within M 67. We detected 68 variables, 43 of which are new detection. Variable periods and proper-motion memberships of a large majority of sources in our catalogue are improved with respect to previous releases. The entire catalogue will be available in electronic format. Besides the general interest on an improved catalogue, this work will be particularly useful because of: (1) the imminent release of Kepler/K2 Campaign-5 data of this cluster, for which our catalogue will provide an excellent, high spatial resolution input list, and (2) characterisation of the M 67 stars which are targets of intense HARPS and HARPS-N radial-velocity surveys for planet search.Comment: 8 pages, 6 figures (2 at low resolution), 2 tables. Accepted for publication in MNRAS on October 17, 2015. Electronic materials available at the url http://groups.dfa.unipd.it/ESPG/M67.html , and later on the Journal and at the CD

TASTE. III. A homogeneous study of transit time variations in WASP-3b

The TASTE project is searching for low-mass planets with the Transit Timing Variation (TTV) technique, by gathering high-precision, short-cadence light curves for a selected sample of transiting exoplanets. It has been claimed that the "hot Jupiter" WASP-3b could be perturbed by a second planet. Presenting eleven new light curves (secured at the IAC80 and UDEM telescopes) and re-analyzing thirty-eight archival light curves in a homogeneous way, we show that new data do not confirm the previously claimed TTV signal. However, we bring evidence that measurements are not consistent with a constant orbital period, though no significant periodicity can be detected. Additional dynamical modeling and follow-up observations are planned to constrain the properties of the perturber or to put upper limits to it. We provide a refined ephemeris for WASP-3b and improved orbital/physical parameters. A contact eclipsing binary, serendipitously discovered among field stars, is reported here for the first time.Comment: 10 pages, 6 figures, 4 tables; accepted for publication in A&

Acoustic Emission from a Growing Crack

Separation of crack growth signals is of fundamental importance for detecting, locating, and determining the significance of an internal flaw. The difficulty associated with modeling acoustic emission is not only in providing an accurate representation of the source mechanism, but also in determining the effect of the specimen geometry and the sensor on the acoustic emission signal

Investigation of current noise in underdamped Josephson devices by switching current measurements

AbstractExperimental measurements on critical current noise in underdamped niobium based Josephson devices by a technique based on the switching current measurements is reported. By sweeping the junction with a current ramp we measure the critical current switching as a function of the time using the standard time of flight technique. In such a way it is possible to obtain the critical current fluctuations ΔIc=Ic(t)-<Ic(t)> and the relative standard deviations which corresponds to the root square of the current fluctuation power. Pointing at the white noise fluctuations (above few Hz) and taking into account the physical frequency of the device, it is possible to evaluate the power spectral density of the critical current. The analysis has involved high quality underdamped Josephson junctions having an area ranging from (4x4) μm2 to (40x40) μm2 in the temperature range from 4.2K to few tenth of mK. These measurement provide very useful information about the intrinsic noise of Josephson devices involving SQUIDs and qubits

Innate effector cells in angiogenesis and lymphangiogenesis

Angiogenesis and lymphangiogenesis are distinct and complex processes requiring a finely tuned balance between stimulatory and inhibitory signals. During adulthood, angiogenesis and lymphangiogenesis are activated at sites of tumor growth, tissue injury and remodeling, and chronic inflammation. Vascular endothelial growth factors (VEGFs), angiopoietin (ANGPTs) and a multitude of additional signaling molecules play distinct roles in the modulation of angiogenesis/lymphangiogenesis. VEGFs and ANGPTs activate specific tyrosine kinase receptor (e.g., VEGFR1, VEGFR-2, VEGFR-3 and TIE2 respectively), expressed on blood endothelial cells (angiogenesis) and lymphatic endothelial cells (lymphangiogenesis). Although tumor cells produce VEGFs and other proangiogenic mediators, tissue resident (e.g., macrophages, mast cells) and circulating immune cells (e.g., basophils, neutrophils, monocytes, eosinophils) are an important source of angiogenic/lymphangiogenic mediators in inflammation and in tumor microenvironment and at site of chronic inflammation. Certain immune cells can also release anti-angiogenic factors. Mast cells, basophils, neutrophils and presumably other immune cells are not only a source of angiogenic/lymphangiogenic molecules, but also their target. Cells of the immune system need consideration as major players and possible targets for therapeutic manipulation of angiogenesis/lymphangiogenesis in chronic inflammatory disorders and tumors

Persistent and Coupling Current Effects in the LHC Superconducting Dipoles

One of the main issues for the operation of the LHC accelerator at CERN is the field errors generated by persistent and coupling currents in the main dipoles at injection conditions, i.e., 0.54 T dipole field. For this reason we are conducting systematic magnetic field measurements to quantify the above effects and compare them to the expected values from measurement on strands and cables. We discuss the results in terms of DC effects from persistent current magnetization, AC effects with short time constant from strand and cable coupling currents, and long-term decay during constant current excitation. Average and spread of the measured field errors over the population of magnets tested are as expected or smaller. Field decay at injection, and subsequent snap-back, show for the moment the largest variation from magnet to magnet, with weak correlation to parameters that can be controlled during production. For this reason these effects are likely to result in the largest spread of field errors over the whole dipole production