Constraining Type Ia Supernovae progenitors from three years of SNLS data

While it is generally accepted that Type Ia supernovae are the result of the explosion of a carbon-oxygen White Dwarf accreting mass in a binary system, the details of their genesis still elude us, and the nature of the binary companion is uncertain. Kasen (2010) points out that the presence of a non-degenerate companion in the progenitor system could leave an observable trace: a flux excess in the early rise portion of the lightcurve caused by the ejecta impact with the companion itself. This excess would be observable only under favorable viewing angles, and its intensity depends on the nature of the companion. We searched for the signature of a non-degenerate companion in three years of Supernova Legacy Survey data by generating synthetic lightcurves accounting for the effects of shocking and comparing true and synthetic time series with Kolmogorov-Smirnov tests. Our most constraining result comes from noting that the shocking effect is more prominent in rest-frame B than V band: we rule out a contribution from white dwarf-red giant binary systems to Type Ia supernova explosions greater than 10% at 2 sigma, and than 20% at 3 sigma level.Comment: 14 pages, 15 figures, resubmitted to ApJ, figure 15 modifie

Differential clearance rates of microbial phylotypes by four appendicularian species

Appendicularians are abundant planktonic filter feeders that play a significant role in the pelagic food web due to their high clearance rates. Their diet and feeding rates have typically been measured as bulk chlorophyll or cell removal, with some attention given to prey size but no differentiation between the microbial phylotypes. Using a combination ofin situand laboratory incubations with flow cytometry and next-generation sequencing, we found species-specific differences in clearance rates and diet compositions of 4 common species:Oikopleura albicans,O. fusiformis,O. longicauda, andO. dioica. WhileO. albicansmost efficiently removed nano-eukaryotic algae, the other smaller species preferentially removed micron-sized pico-eukaryotic algae. Pico- and nano-eukaryotic cells constituted the major food source of the studied appendicularians despite their occurrence in oligotrophic water dominated by prokaryotic cells. Across species, pico- and nano-planktonic microalgae biomass comprised 45 to 75% of the appendicularian diets. Although non-photosynthetic bacteria were removed at lower rates than all other prey groups, their total contribution to the appendicularian diet was not trivial, representing 5 to 19% of the planktonic carbon in the appendicularian diet; pico-cyanobacteria contributed an additional 9 to 18%. Removal rates and efficiencies of pico-eukaryotes were higher than those of prokaryotes of similar size. Strikingly different clearance rates were observed for different prokaryotic phylotypes, indicating that factors other than size are involved in determining the capturability of the cells. Collectively, our findings provide additional evidence for differential retention of microbial prey among mucous-mesh grazers and its substantial effect on the upper-ocean microbial community.</jats:p

The effect of progenitor age and metallicity on luminosity and 56Ni yield in Type Ia supernovae

Timmes, Brown & Truran found that metallicity variations could theoretically account for a 25% variation in the mass of 56Ni synthesized in Type Ia supernovae (SNe Ia), and thus account for a large fraction of the scatter in observed SN Ia luminosities. Higher-metallicity progenitors are more neutron-rich, producing more stable burning products relative to radioactive 56Ni. We develop a new method for estimating bolometric luminosity and 56Ni yield in SNe Ia and use it to test the theory with data from the Supernova Legacy Survey. We find that the average 56Ni yield does drop in SNe Ia from high metallicity environments, but the theory can only account for 7%--10% of the dispersion in SN Ia 56Ni mass, and thus luminosity. This is because the effect is dominant at metallicities significantly above solar, whereas we find that SN hosts have predominantly subsolar or only moderately above-solar metallicities. We also show that allowing for changes in O/Fe with the metallicity [Fe/H] does not have a major effect on the theoretical prediction of Timmes, Brown & Truran, so long as one is using the O/H as the independent variable. Age may have a greater effect than metallicity -- we find that the luminosity weighted age of the host galaxy is correlated with 56Ni yield, and thus more massive progenitors give rise to more luminous explosions. This is hard to understand if most SNe Ia explode when the primaries reach the Chandrasekhar mass. Finally, we test the findings of Gallagher et al., that the residuals of SNe Ia from the Hubble diagram are correlated with host galaxy metallicity, and we find no such correlation.Comment: ApJ, accepted, 34 pages, 11 figures, apologies for one column format -- necessary for the equation

NCI-MATCH Arms N & P: Phase II study of PI3K beta inhibitor GSK2636771 in patients (pts) with cancers (ca) with PTEN mutation/deletion (mut/del) or PTEN protein loss

Background: The NCI-MATCH trial is the largest national study (1173 sites) for ptswith relapsed/ refractory solid tumors, lymphomas and myeloma, which assigns tar-geted therapies based on individual tumor molecular alterations detected using theadapted Oncomine AmpliSeq panel (143 genes) and immunohistochemistry (IHC).We hypothesized that patients with PTEN-deficient cancers enrolled to Arms N and Pmay benefit from treatment with the PI3K beta-selective inhibitor GSK2636771. Methods: Eligibility: relapsed/refractory ca, good end-organ function, and ECOG PS ≤ 1. Pts were screened for molecular alterations by centralized testing on fresh tumor biopsy and had deleterious PTEN mut/del without loss of expression (Arm N) or complete loss of cytoplasmic and nuclear PTEN staining on IHC (Arm P), and no other aberrations activating the PI3K/MTOR and MAPK pathways (mut in PIK3CA, PIK3R1, BRAF, KRAS, AKT1, TSC1/2, mTOR, RHEB, NF2, NRAS, HRAS). Pts received GSK2636771 400mg/day (28-days cycles). RECIST 1.1 overall response rate (ORR) was the primary endpoint. Results: Of 59 enrolled pts, 56 were eligible and received treatment. Of 22 pts with PTEN mut/del (Arm N: 6 uterine, 2 breast, 2 prostate, 2 head/neck ca, 10 other), all are off treatment as of analysis (14 disease progression, 4 for adverse events [AEs], 4 other). One pt (4.5%) with prostate ca (PTEN deletion, MPRSS2-ERG fusion) attained a partial response (-42%). Of 7 (32%) pts with stable disease (SD), 2 had SD \u3e 6 months (uterine leiomyosarcoma; endometrial carcinoma). Of 34 pts with loss of PTEN protein by IHC (Arm P: 7 prostate, 6 breast, 3 squamous anal ca, 2 cholangiocarcinoma, 16 other), all are off treatment as of analysis (26 disease progression, 4 for AE, 4 other). Of 9 (37.5%) pts with SD, 3 had SD \u3e 6 months (prostate cancer; squamous bladder cancer, squamous anal cancer). Median progression-free survival was 1.8 months for both arms. Gr ≥ 3 treatment-related (tr) reversible toxicities were experienced by 30% (7) and 20% (7) of pts in arms N and P, respectively. No tr Gr 5 toxicities were observed in either arm. Conclusions: Single agent GSK2636771 has very modest activity in ca with PTEN gene mutation/deletion and/or PTEN protein loss

The random case of Conley's theorem: III. Random semiflow case and Morse decomposition

In the first part of this paper, we generalize the results of the author \cite{Liu,Liu2} from the random flow case to the random semiflow case, i.e. we obtain Conley decomposition theorem for infinite dimensional random dynamical systems. In the second part, by introducing the backward orbit for random semiflow, we are able to decompose invariant random compact set (e.g. global random attractor) into random Morse sets and connecting orbits between them, which generalizes the Morse decomposition of invariant sets originated from Conley \cite{Con} to the random semiflow setting and gives the positive answer to an open problem put forward by Caraballo and Langa \cite{CL}.Comment: 21 pages, no figur

Mobility of thorium ions in liquid xenon

We present a measurement of the $^{226}$Th ion mobility in LXe at 163.0 K and 0.9 bar. The result obtained, 0.240$\pm$0.011 (stat) $\pm$0.011 (syst) cm$^{2}$/(kV-s), is compared with a popular model of ion transport.Comment: 6.5 pages,

Technical Note: Ozonesonde climatology between 1995 and 2011: description, evaluation and applications

An ozone climatology based on ozonesonde measurements taken over the last 17 yr has been constructed for model evaluation and comparisons to other observations. Vertical ozone profiles for 42 stations around the globe have been compiled for the period 1995–2011, in pressure and tropopause-referenced altitudes. For each profile, the mean, standard deviation, median, the half-width are provided, as well as information about interannual variability. Regional aggregates are formed in combining stations with similar ozone characteristics. The Hellinger distance is introduced as a new diagnostic to identify stations that describe similar shapes of ozone probability distribution functions (PDFs). In this way, 12 regions were selected covering at least 2 stations and the variability among those stations is discussed. Significant variability with longitude of ozone distributions in the troposphere and lower stratosphere in the northern mid- and high latitudes is found. The representativeness of regional aggregates is discussed for high northern latitudes, Western Europe, Eastern US, and Japan, using independent observations from surface stations and MOZAIC aircraft data. Good agreement exists between ozonesondes and aircraft observations in the mid-troposphere and between ozonesondes and surface observations for Western Europe. For Eastern US and high northern latitudes, surface ozone values from ozonesondes are biased 10 ppb high compared to independent measurements. An application of the climatology is presented using the NCAR CAM-Chem model. The climatology allows evaluation of the model performance regarding ozone averages, seasonality, interannual variability, and the shape of ozone distributions. The new assessment of the key features of ozone distributions gives deeper insights into the performance of models

A linear RFQ ion trap for the Enriched Xenon Observatory

The design, construction, and performance of a linear radio-frequency ion trap (RFQ) intended for use in the Enriched Xenon Observatory (EXO) are described. EXO aims to detect the neutrinoless double-beta decay of $^{136}$Xe to $^{136}$Ba. To suppress possible backgrounds EXO will complement the measurement of decay energy and, to some extent, topology of candidate events in a Xe filled detector with the identification of the daughter nucleus ($^{136}$Ba). The ion trap described here is capable of accepting, cooling, and confining individual Ba ions extracted from the site of the candidate double-beta decay event. A single trapped ion can then be identified, with a large signal-to-noise ratio, via laser spectroscopy.Comment: 18 pages, pdflatex, submitted to NIM

Type Ia Supernovae as Stellar Endpoints and Cosmological Tools

Empirically, Type Ia supernovae are the most useful, precise, and mature tools for determining astronomical distances. Acting as calibrated candles they revealed the presence of dark energy and are being used to measure its properties. However, the nature of the SN Ia explosion, and the progenitors involved, have remained elusive, even after seven decades of research. But now new large surveys are bringing about a paradigm shift --- we can finally compare samples of hundreds of supernovae to isolate critical variables. As a result of this, and advances in modeling, breakthroughs in understanding all aspects of SNe Ia are finally starting to happen.Comment: Invited review for Nature Communications. Final published version. Shortened, update

Local Optical Probe of Motion and Stress in a multilayer graphene NEMS

Nanoelectromechanical systems (NEMSs) are emerging nanoscale elements at the crossroads between mechanics, optics and electronics, with significant potential for actuation and sensing applications. The reduction of dimensions compared to their micronic counterparts brings new effects including sensitivity to very low mass, resonant frequencies in the radiofrequency range, mechanical non-linearities and observation of quantum mechanical effects. An important issue of NEMS is the understanding of fundamental physical properties conditioning dissipation mechanisms, known to limit mechanical quality factors and to induce aging due to material degradation. There is a need for detection methods tailored for these systems which allow probing motion and stress at the nanometer scale. Here, we show a non-invasive local optical probe for the quantitative measurement of motion and stress within a multilayer graphene NEMS provided by a combination of Fizeau interferences, Raman spectroscopy and electrostatically actuated mirror. Interferometry provides a calibrated measurement of the motion, resulting from an actuation ranging from a quasi-static load up to the mechanical resonance while Raman spectroscopy allows a purely spectral detection of mechanical resonance at the nanoscale. Such spectroscopic detection reveals the coupling between a strained nano-resonator and the energy of an inelastically scattered photon, and thus offers a new approach for optomechanics