Context. Observationally, supernovae (SNe) are divided into subclasses according to their distinct characteristics. This diversity naturally reflects the diversity in the progenitor stars. It is not ...entirely clear, however, how different evolutionary paths leading massive stars to become an SN are governed by fundamental parameters such as progenitor initial mass and metallicity. Aims. This paper places constraints on progenitor initial mass and metallicity in distinct core-collapse SN subclasses through a study of the parent stellar populations at the explosion sites. Methods. Integral field spectroscopy (IFS) of 83 nearby SN explosion sites with a median distance of 18 Mpc has been collected and analysed, enabling detection and spectral extraction of the parent stellar population of SN progenitors. From the parent stellar population spectrum, the initial mass and metallicity of the coeval progenitor are derived by means of comparison to simple stellar population models and strong-line methods. Additionally, near-infrared IFS was employed to characterise the star formation history at the explosion sites. Results. No significant metallicity differences are observed among distinct SN types. The typical progenitor mass is found to be highest for SN type Ic, followed by type Ib, then types IIb and II. Type IIn is the least associated with young stellar populations and thus massive progenitors. However, statistically significant differences in progenitor initial mass are observed only when comparing SNe IIn with other subclasses. Stripped-envelope SN progenitors with initial mass estimates lower than 25 M⊙ are found; they are thought to be the result of binary progenitors. Confirming previous studies, these results support the notion that core-collapse SN progenitors cannot arise from single-star channels only, and both single and binary channels are at play in the production of core-collapse SNe. Near-infrared IFS suggests that multiple stellar populations with different ages may be present in some of the SN sites. As a consequence, there could be a non-negligible amount of contamination from old populations, and therefore the individual age estimates are effectively lower limits.
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Aims. We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift ...samples (z< 0.1), all three seasons from the SDSS-II (0.05 <z< 0.4), and three years from SNLS (0.2 <z< 1), and it totals 740 spectroscopically confirmed type Ia supernovae with high-quality light curves. Methods. We followed the methods and assumptions of the SNLS three-year data analysis except for the following important improvements: 1) the addition of the full SDSS-II spectroscopically-confirmed SN Ia sample in both the training of the SALT2 light-curve model and in the Hubble diagram analysis (374 SNe); 2) intercalibration of the SNLS and SDSS surveys and reduced systematic uncertainties in the photometric calibration, performed blindly with respect to the cosmology analysis; and 3) a thorough investigation of systematic errors associated with the SALT2 modeling of SN Ia light curves. Results. We produce recalibrated SN Ia light curves and associated distances for the SDSS-II and SNLS samples. The large SDSS-II sample provides an effective, independent, low-z anchor for the Hubble diagram and reduces the systematic error from calibration systematics in the low-z SN sample. For a flat ΛCDM cosmology, we find Ωm =0.295 ± 0.034 (stat+sys), a value consistent with the most recent cosmic microwave background (CMB) measurement from the Planck and WMAP experiments. Our result is 1.8σ (stat+sys) different than the previously published result of SNLS three-year data. The change is due primarily to improvements in the SNLS photometric calibration. When combined with CMB constraints, we measure a constant dark-energy equation of state parameter w =−1.018 ± 0.057 (stat+sys) for a flat universe. Adding baryon acoustic oscillation distance measurements gives similar constraints: w =−1.027 ± 0.055. Our supernova measurements provide the most stringent constraints to date on the nature of dark energy.
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Dynamic coarse graining is a procedure to map a dynamical system with large degrees of freedom to a system with smaller degrees of freedom by properly choosing coarse grained variables. This ...procedure has been conducted mainly by empiricisms. In this paper, I will discuss a theoretical principle which may be useful for this procedure. I will discuss how to choose coarse grained variables (or slow variables), and how to set up their evolution equations. To this end, I will review the classical example of dynamic coarse graining, i.e., the Brownian motion theory, and show a variational principle for the evolution of the slow variables. The principle, called the Onsager principle, is useful not only to derive the evolution equations, but also to solve the problems.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A possible method to solve the sign problem is developed by modifying the original theory. Considering several modifications of the partition function, the observable in the original theory is ...reconstructed from the identity connecting the observables in the original and modified theories. We demonstrate that our method gives the correct results, even if the original theory has the severe sign problem, by using a simple one-dimensional integral.
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Evidence is limited regarding the association between low-carbohydrate diet (LCD) score and mortality among Asians, a population that consumes a large amount of carbohydrates.
The present study ...examined the association between low-carbohydrate diet (LCD) score (based on percentage of energy as carbohydrate, fat, and protein) and the risk of total and cause-specific mortality among Asians.
This study was a prospective cohort study in Japan with follow-up for a median of 16.9 years involving 43008 men and 50646 women aged 45–75 years. Association of LCD score, LCD score based on animal sources of protein and fat, and LCD score based on plant sources of protein and fat with risk of mortality was assessed using Cox proportional hazards model.
A U-shaped association was observed between LCD score and total mortality: the multivariable-adjusted hazard ratios (HRs) (95% CI) of total mortality for lowest through highest scores were 1.00, 0.95 (0.91, 1.01), 0.93 (0.88, 0.98), 0.93 (0.88, 0.98), and 1.01 (0.95, 1.07) (P-non-linearity <0.01). A similar association was found for mortality from cardiovascular disease (CVD) and heart disease. LCD score based on carbohydrate, animal protein, and animal fat also showed a U-shaped association for total mortality (P-non-linearity <0.01). In contrast, LCD score based on carbohydrate, plant protein, and plant fat was linearly associated with lower total (HR, 0.89; 95% CI: 0.83, 0.94 for highest versus lowest quintile), CVD 0.82 (0.73, 0.92), heart disease 0.83 (0.71, 0.98), and cerebrovascular disease 0.75 (0.62, 0.91) mortality.
Both LCD with high animal protein and fat and high-carbohydrate diet with low animal protein and fat were associated with higher risk of mortality. Meanwhile, LCD high in plant-based sources of protein and fat was associated with a lower risk of total and CVD mortality.
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We detected Zika virus in breast milk of a woman in Brazil infected with the virus during the 36th week of pregnancy. Virus was detected 33 days after onset of signs and symptoms and 9 days after ...delivery. No abnormalities were found during fetal assessment or after birth of the infant.
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We report on work to increase the number of well-measured Type Ia supernovae (SNe Ia) at high redshifts. Light curves, including high signal-to-noise Hubble Space Telescope data, and spectra of six ...SNe Ia that were discovered during 2001, are presented. Additionally, for the two SNe with z > 1, we present ground-based J-band photometry from Gemini and the Very Large Telescope. These are among the most distant SNe Ia for which ground-based near-IR observations have been obtained. We add these six SNe Ia together with other data sets that have recently become available in the literature to the Union compilation. We have made a number of refinements to the Union analysis chain, the most important ones being the refitting of all light curves with the SALT2 fitter and an improved handling of systematic errors. We call this new compilation, consisting of 557 SNe, the Union2 compilation. The flat concordance ΛCDM model remains an excellent fit to the Union2 data with the best-fit constant equation-of-state parameter w = -0.997+0.050 -0.054(stat)+0.077 -0.082(stat + sys together) for a flat universe, or w = -1.038+0.056 -0.059(stat)+0.093 -0.097(stat + sys together) with curvature. We also present improved constraints on w(z). While no significant change in w with redshift is detected, there is still considerable room for evolution in w. The strength of the constraints depends strongly on redshift. In particular, at z >~ 1, the existence and nature of dark energy are only weakly constrained by the data. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute (STScI). STScI is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under the NASA contract NAS 5-26555. The observations are associated with programs HST-GO-08585 and HST-GO-09075. Based, in part, on observations obtained at the ESO La Silla Paranal Observatory (ESO programs 67.A-0361 and 169.A-0382). Based, in part, on observations obtained at the Cerro-Tololo Inter-American Observatory (CTIO), National Optical Astronomy Observatory (NOAO). Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT). Based, in part, on observations obtained at the Gemini Observatory (Gemini programs GN-2001A-SV-19 and GN-2002A-Q-31). Based, in part on observations obtained at the Subaru Telescope. Based, in part, on data that were obtained at the W. M. Keck Observatory.
SmFe12-based compounds have been considered as promising candidates for next generation permanent magnet materials because of their excellent intrinsic hard magnetic properties with a minimum usage ...of rare earth elements. However, realizing high coercivity in anisotropic microstructure is a big challenge, which hinders their practical applications. In this work, a novel anisotropic granular microstructure of Sm(Fe0.8Co0.2)12 with a sufficiently large coercivity (µ0Hc) of 1.2 T and with a high remanent magnetization of 1.50 T is demonstrated in thin films prepared by co-sputtering Sm(Fe,Co)12 with boron. Detailed microstructure characterization using high resolution scanning transmission electron microscopy (STEM) and atom probe tomography (APT) indicate that the addition of B leads to the development of columnar-shaped Sm(Fe0.8Co0.2)12 grains with a size of ∼40 nm, which are surrounded by ∼3 nm-thick B-enriched amorphous intergranular phase. Domain wall pinning at the amorphous grain boundary phase is attributed to the high coercivity. This work provides a guiding principle for realizing high-coercivity anisotropic SmFe12-based permanent magnets, which can outperform Nd-Fe-B magnets and could be used as the next-generation high-performance permanent magnets in various applications.
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Soft matter represents a collection of materials such as polymer, colloids, surfactants, and liquid crystals and their composites. These materials do not belong to conventional classes of materials ...(simple fluids or solids), but they are used extensively in our everyday life and in modern technology (in displays, device manufacturing, energy-saving technology, bio-medical applications, etc.). Soft matter consists of units much larger than atoms; their typical length is 0.01 μm–100 μm. This gives two characteristics to soft matter: large non-linear response to external forces; and long relaxation time and slow dynamics. The aim of this book is to discuss the materials of such characteristics for undergraduate and graduate course students explaining basic physical concepts such as phase transition and Brownian motion. Attempts have been made to connect such physics to our experience in everyday life.
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