Strongly lensed SNe Ia in the era of LSST: observing cadence for lens discoveries and time-delay measurements

The upcoming Large Synoptic Survey Telescope (LSST) will detect many strongly lensed Type Ia supernovae (LSNe Ia) for time-delay cosmography. This will provide an independent and direct way for measuring the Hubble constant $H_0$, which is necessary to address the current $4.4 \sigma$ tension in $H_0$ between the local distance ladder and the early Universe measurements. We present a detailed analysis of different observing strategies for the LSST, and quantify their impact on time-delay measurement between multiple images of LSNe Ia. For this, we produced microlensed mock-LSST light curves for which we estimated the time delay between different images. We find that using only LSST data for time-delay cosmography is not ideal. Instead, we advocate using LSST as a discovery machine for LSNe Ia, enabling time delay measurements from follow-up observations from other instruments in order to increase the number of systems by a factor of 2 to 16 depending on the observing strategy. Furthermore, we find that LSST observing strategies, which provide a good sampling frequency (the mean inter-night gap is around two days) and high cumulative season length (ten seasons with a season length of around 170 days per season), are favored. Rolling cadences subdivide the survey and focus on different parts in different years; these observing strategies trade the number of seasons for better sampling frequency. In our investigation, this leads to half the number of systems in comparison to the best observing strategy. Therefore rolling cadences are disfavored because the gain from the increased sampling frequency cannot compensate for the shortened cumulative season length. We anticipate that the sample of lensed SNe Ia from our preferred LSST cadence strategies with rapid follow-up observations would yield an independent percent-level constraint on $H_0$.Comment: 25 pages, 22 figures; accepted for publication in A&

Explosive Nucleosynthesis: What we learned and what we still do not understand

This review touches on historical aspects, going back to the early days of nuclear astrophysics, initiated by B$^2$FH and Cameron, discusses (i) the required nuclear input from reaction rates and decay properties up to the nuclear equation of state, continues (ii) with the tools to perform nucleosynthesis calculations and (iii) early parametrized nucleosynthesis studies, before (iv) reliable stellar models became available for the late stages of stellar evolution. It passes then through (v) explosive environments from core-collapse supernovae to explosive events in binary systems (including type Ia supernovae and compact binary mergers), and finally (vi) discusses the role of all these nucleosynthesis production sites in the evolution of galaxies. The focus is put on the comparison of early ideas and present, very recent, understanding.Comment: 11 pages, to appear in Springer Proceedings in Physics (Proc. of Intl. Conf. "Nuclei in the Cosmos XV", LNGS Assergi, Italy, June 2018

Nova-like Cataclysmic Variables in the Infrared

Novalike cataclysmic variables have persistently high mass transfer rates and prominent steady state accretion disks. We present an analysis of infrared observations of twelve novalikes obtained from the Two Micron All Sky Survey, the Spitzer Space Telescope, and the Wide-field Infrared Survey Explorer All Sky Survey. The presence of an infrared excess at >3-5 microns over the expectation of a theoretical steady state accretion disk is ubiquitous in our sample. The strength of the infrared excess is not correlated with orbital period, but shows a statistically significant correlation (but shallow trend) with system inclination that might be partially (but not completely) linked to the increasing view of the cooler outer accretion disk and disk rim at higher inclinations. We discuss the possible origin of the infrared excess in terms of emission from bremsstrahlung or circumbinary dust, with either mechanism facilitated by the mass outflows (e.g., disk wind/corona, accretion stream overflow, and so on) present in novalikes. Our comparison of the relative advantages and disadvantages of either mechanism for explaining the observations suggests that the situation is rather ambiguous, largely circumstantial, and in need of stricter observational constraints.Peer reviewe

New Clathrin-Based Nanoplatforms for Magnetic Resonance Imaging

Background: Magnetic Resonance Imaging (MRI) has high spatial resolution, but low sensitivity for visualization of molecular targets in the central nervous system (CNS). Our goal was to develop a new MRI method with the potential for non-invasive molecular brain imaging. We herein introduce new bio-nanotechnology approaches for designing CNS contrast media based on the ubiquitous clathrin cell protein. Methodology/Principal Findings: The first approach utilizes three-legged clathrin triskelia modified to carry 81 gadolinium chelates. The second approach uses clathrin cages self-assembled from triskelia and designed to carry 432 gadolinium chelates. Clathrin triskelia and cages were characterized by size, structure, protein concentration, and chelate and gadolinium contents. Relaxivity was evaluated at 0.47 T. A series of studies were conducted to ascertain whether fluorescent-tagged clathrin nanoplatforms could cross the blood brain barriers (BBB) unaided following intranasal, intravenous, and intraperitoneal routes of administration. Clathrin nanoparticles can be constituted as triskelia (18.5 nm in size), and as cages assembled from them (55 nm). The mean chelate: clathrin heavy chain molar ratio was 27.0464.8: 1 fo

Models for Type Ia supernovae and related astrophysical transients

We give an overview of recent efforts to model Type Ia supernovae and related astrophysical transients resulting from thermonuclear explosions in white dwarfs. In particular we point out the challenges resulting from the multi-physics multi-scale nature of the problem and discuss possible numerical approaches to meet them in hydrodynamical explosion simulations and radiative transfer modeling. We give examples of how these methods are applied to several explosion scenarios that have been proposed to explain distinct subsets or, in some cases, the majority of the observed events. In case we comment on some of the successes and shortcoming of these scenarios and highlight important outstanding issues.Comment: 20 pages, 2 figures, review published in Space Science Reviews as part of the topical collection on supernovae, replacement corrects typos in the conclusions sectio

Der Radiologe / Weichteilsarkome : Wie lassen sich posttherapeutische Veränderungen von Rezidiven unterscheiden?

Die Erkennung von Weichteilsarkomrezidiven und ihre Differenzierung von posttherapeutischen Veränderungen sind komplex. Der Beitrag soll dem klinisch tätigen Radiologen helfen, lokale Nachkontrollen systematisch zu beurteilen. Voraussetzungen sind einerseits die genaue Kenntnis der klinischen und therapeutischen Anamnese und der aktuellen klinischen Situation sowie andererseits eine adäquate Untersuchungstechnik, für die Empfehlungen gegeben werden, und ein Vergleich mit der initialen Bildgebung. Der Beitrag gibt einen Überblick über Rezidivhäufigkeiten und Therapiemodalitäten wie der Operation, Bestrahlung und Chemotherapie. Er beschreibt das MR(Magnetresononanz)-tomographische Spektrum regulärer posttherapeutischer Veränderungen im zeitlichen Ablauf und geht auf therapieassoziierte Komplikationen ein. Diese umfassen akute Komplikationen, wie Serome, Hämatome oder Infektionen, und späte Komplikationen, wie Ödeme, Fibrosen und Gelenksteife, sowie nach variablen Intervallen auftretende Pseudotumoren. Diesen Veränderungen gegenübergestellt wird das Erscheinungsbild von Rezidiven und strahlenassoziierten Sarkomen. Es werden insbesondere MR-tomographische Kriterien vorgestellt, die helfen können, posttherapeutische Veränderungen von Rezidiven besser zu unterscheiden.The recognition of recurrent soft tissue sarcomas and the differentiation from post-treatment alterations is complex. This article aims to assist the clinical radiologist in the systematic evaluation of local follow-up imaging in soft tissue sarcoma patients. Soft tissue sarcomas encompass multiple entities with different recurrence rates and follow-up intervals. Approved and up to date recommendations are provided, including imaging techniques. The past medical history of the patient, the clinical situation and previous therapies should be known in detail, including surgery, radiation therapy and chemotherapy. Previous imaging results should be consulted, if available. This article describes the time-dependent imaging spectrum of local post-therapeutic as well as local treatment-related complications. These include early complications, such as seromas, hematomas and infections, as well as late complications, including edema, fibrosis and joint stiffness, and also inflammatory pseudotumors, which may occur after variable time intervals. The imaging appearance of local recurrent and radiation-associated sarcoma are elucidated. In particular, magnetic resonance imaging (MRI) criteria are provided, which may help in differentiating post-therapeutic alterations from recurrent soft tissue sarcomas.(VLID)356974

Design and Development of a Graphical Setup Software for the CMS Global Trigger

The CMS experiment at CERNs Large Hadron Collider will search for new physics at high energies. Its trigger system is an essential component in the selection process of potentially interesting events. The Global Trigger is the final stage of the first-level selection process. It is implemented as a complex electronic system containing logic devices, which need to be programmed according to physics requirements. It has to reject or accept events for further processing based on coarse measurements of particle properties such as energies, momenta and location. Algorithms similar to the ones used in the physics analysis are executed in parallel during the event selection process. A graphical setup program to define these algorithms and to subsequently configure the hardware has been developed. The design and implementation of the program, guided by the principal requirements of flexibility, quality assurance, platform-independence and extensibility, are described

Hand MRI and the Greulich-Pyle atlas in skeletal age estimation in adolescents

Objective To evaluate the feasibility of hand MRI in age assessment in adolescents using the Greulich-Pyle (GP) atlas criteria. Materials and methods Two radiologists, who were blinded to the study subjects chronologic ages, semi-objectively evaluated 1.5-T MRIs of the left hands of ten patients (13.52.6 years) who had left-hand radiographs and 50 healthy volunteers (152 years). Results A coronal T1-weighted, volumetric, interpolated, breath-hold examination with water excitation (T1 VIBE-3D-WE) achieved the best image quality. The correlation between estimated patients ages on radiographs and MRI was high. The average estimated age difference between the MRIs and radiographs was 0.05 years for reader 1 and 0.175 years for reader 2. The interclass coefficients (ICCs) showed high interobserver agreement (radiographs: ICC=0.95, MRI: ICC=0.97). The ICC, calculated separately for the male and female volunteers estimated ages by MRI, also showed a high agreement between the two readers (male: ICC=0.97, female: ICC=0.95). Reader 1 estimated 94% of volunteers within 2 standard deviations (SD) and 62% within 1 SD. The results for reader 2 were 92% and 54%, respectively. Thirty-nine percent of girls and 27% of boys were estimated to be older using 1 SD. Conclusion MRI of the left hand is a feasible alternative to hand radiographs for skeletal age estimation in adolescents using the GP criteria with 2 SD. Using 1 SD, the age of healthy volunteers tended to be estimated as higher than the chronologic age. Future studies should evaluate the results in a larger number of participants.(VLID)358223

Soft Tissue Sarcoma Follow-up Imaging: Strategies to Distinguish Post-treatment Changes from Recurrence (vol 24, pg 627, 2020)

Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas