Temporal Localized Structures in mode-locked Vertical External-Cavity Surface-Emitting Lasers

Temporal Localized States (TLSs) are individually addressable structures traveling in optical resonators. They can be used as bits of information and to generate frequency combs with tunable spectral density. We show that a pair of specially designed nonlinear mirrors, a 1/2 Vertical-Cavity Surface-Emitting Laser and a Semiconductor Saturable Absorber, coupled in self-imaging conditions, can lead to the generation of such TLSs. Our results indicate how a conventional passive mode- locking scheme can be adapted to provide a robust and simple system emitting TLSs and it paves the way towards the observation of three dimensions confined states, the so-called light bullets.Comment: submission to Optics Letter

Third Order Dispersion in Time-Delayed Systems

[eng] Time-delayed dynamical systems materialize in situations where distant, pointwise, nonlinear nodes exchange information that propagates at a finite speed. However, they are considered devoid of dispersive effects, which are known to play a leading role in pattern formation and wave dynamics. We show how dispersion may appear naturally in delayed systems and we exemplify our result by studying theoretically and experimentally the influence of third order dispersion in a system composed of coupled optical microcavities. Dispersion-induced pulse satellites emerge symmetrically and destabilize the mode-locking regime

The Distance to SN 1999em in NGC 1637 from the Expanding Photosphere Method

We present 30 optical spectra and 49 photometric epochs sampling the first 517 days after discovery of supernova (SN) 1999em, and derive its distance through the expanding photosphere method (EPM). SN 1999em is shown to be a Type II-plateau (II-P) event, with a photometric plateau lasting until about 100 days after explosion. We identify the dominant ions responsible for most of the absorption features seen in the optical portion of the spectrum during the plateau phase. We find the distance to SN 1999em to be D = 8.2 +/- 0.6 Mpc, with an explosion date of 5.3 +/- 1.4 days before discovery. We examine potential sources of systematic error in EPM-derived distances, and find the most significant to result from uncertainty in the theoretical modeling of the flux distribution emitted by the SN photosphere (i.e., the ``flux dilution factor''). We compare previously derived EPM distances to 5 SNe II in galaxies for which a recently revised Cepheid distance exists from the HST Key Project and find D(Cepheids) / D(EPM) = 0.96 +/- 0.09. Finally, we investigate the possible use of SNe II-P as standard candles and find that for 8 photometrically confirmed SNe II-P with previously derived EPM distances and SN 1999em, the mean plateau absolute brightness is M_V(plateau) = -16.4 +/- 0.6 mag, implying that distances good to ~30% (1-sigma) may be possible without the need for a complete EPM analysis. At M_V(plateau) = -15.9 +/- 0.2 mag, SN 1999em is somewhat fainter than the average SN II-P. The general consistency of absolute SNe II-P brightness during the plateau suggests that the standard candle assumption may allow SNe II-P to be viable cosmological beacons at z > 2.Comment: 79 pages, 26 figures, accepted for publication in the Publications of the Astronomical Society of the Pacifi

IssuEs in Palliative care for people in advanced and terminal stages of Young-onset and Late-Onset dementia in GErmany (EPYLOGE): the study protocol.

Scientific research on palliative care in dementia is still underdeveloped. In particular, there are no research studies at all on palliative care issues in young onset dementia (YOD), although significant differences compared to late onset dementia (LOD) are expected. Most studies have focused on persons with dementia in long term care (LTC) facilities but have neglected persons that are cared for at home. We hypothesize that unmet care needs exist in advanced and terminal stages of YOD and LOD and that they differ between YOD and LOD. The EPYLOGE-study (IssuEs in Palliative care for people in advanced and terminal stages of Young-onset and Late-Onset dementia in GErmany) aims to prospectively assess and survey 200 persons with YOD and LOD in advanced stages who are cared for in LTC facilities and at home. Furthermore, EPYLOGE aims to investigate the circumstances of death of 100 persons with YOD and LOD. This includes 1) describing symptoms and management, health care utilization, palliative care provision, quality of life and death, elements of advance care planning, family caregivers' needs and satisfaction; 2) comparing YOD and LOD regarding these factors; 3) developing expert-consensus recommendations derived from the study results for the improvement and implementation of strategies and interventions for palliative care provision; 4) and communicating the recommendations nationally and internationally in order to improve and adapt guidelines, to change current practice and to give a basis and perspectives for future research projects. The results will also be communicated to patients and their families in order to counsel and support them in their decision making processes and their dialogue with professional caregivers and physicians. EPYLOGE is the first study in Germany that assesses palliative care and end-of-life issues in dementia. Furthermore, it is the first study internationally that focuses on the specific palliative care situation of persons with YOD and their families. EPYLOGE serves as a basis for the improvement of palliative care in dementia. The study is registered in ClinicalTrials.gov ( NCT03364179 ; Registered: 6. December 2017

NEAs: Phase Angle Dependence of Asteroid Class and Diameter from Observational Studies

We will discuss the results of a planned observation campaign of Near Earth Asteroids (NEAs), 1999 CU3, 2002 GM2, 2002 FG7, and 3691 Bede with instruments on the United Kingdom Infrared Telescope (UKIRT) from 15-Mar-2015 to 28-April 2015 UT. We will study the phase-angle dependence of the reflectance and thermal emission spectra. Recent publications reveal that the assignment of the asteroid class from visible and near-IR spectroscopy can change with phase angle for NEAs with silicate-bearing minerals on their surfaces (S-class asteroids) (Thomas et al. 2014, Icarus 228, 217; Sanchez et al. 2012 Icarus 220, 36). Only three of the larger NEAs have been measured at a dozen phase angles and the trends are not all the same, so there is not yet enough information to create a phase-angle correction. Also, the phase angle effect is not characterized well for the thermal emission including determination of the albedo and the thermal emission. The few NEAs were selected for our study amongst many possible targets based on being able to observe them through a wide range of phase angles, ranging from less than about 10 degrees to greater than 45 degrees over the constrained date range. The orbits of NEAs often generate short observing windows at phase angles higher than 45 deg (i.e., whizzing by Earth and/or close to dawn or dusk). Ultimately, lowering the uncertainty of the translation of asteroid class to meteorite analog and of albedo and size determinations are amongst our science goals. On a few specific nights, we plan to observe the 0.75-2.5 micron spectra with IRTF+SpeX for comparison with UKIRT data including 5-20 micron with UKIRT+UIST/Michelle to determine as best as possible the albedos. To ensure correct phasing of spectroscopic data, we augment with TRAPPIST-telescope light curves and R-band guider image data. Our observations will contribute to understanding single epoch mid-IR and near-IR measurements to obtain albedo, size and IR beaming parameters (the outcomes of thermal models) and asteroid spectral class