The merits of a fibre‐rich diet are well documented. Resistant starch (RS) is a form of starch that resists digestion in the small intestine and, as such, is classified as a type of dietary fibre. RS ...can be categorised as one of five types (RS1–5), some of which occur naturally in foods such as bananas, potatoes, grains and legumes and some of which are produced or modified commercially, and incorporated into food products. This review describes human evidence on the health effects of RS consumption, with the aim of identifying any benefits of RS‐rich foods and RS as a functional ingredient. The reduced glycaemic response consistently reported with RS consumption, when compared with digestible carbohydrate, has resulted in an approved European Union health claim. Thus, RS‐rich foods may be particularly useful for managing diabetes. There appears to be little impact of RS on other metabolic markers, such as blood pressure and plasma lipids, though data are comparatively limited. Promising results on markers of gut health suggest that further research may lead to the classification of RS as a prebiotic. Microbial fermentation of RS in the large intestine to produce short‐chain fatty acids likely underpins some of its biological effects, including increasing satiety. However, effects on appetite have not resulted in notable changes in bodyweight after long‐term consumption. Emerging research suggests potential for RS as an ingredient in oral rehydration solutions and in the treatment of chronic kidney disease. Overall, RS possesses positive properties as a healthy food component.
The optical and optical/near-infrared pseudo-bolometric light curves of 85 stripped-envelope supernovae (SNe) are constructed using a consistent method and a standard cosmology. The light curves are ...analysed to derive temporal characteristics and peak luminosity L
p, enabling the construction of a luminosity function. Subsequently, the mass of 56Ni synthesized in the explosion, along with the ratio of ejecta mass to ejecta kinetic energy, are found. Analysis shows that host-galaxy extinction is an important factor in accurately determining luminosity values as it is significantly greater than Galactic extinction in most cases. It is found that broad-lined SNe Ic (SNe Ic-BL) and gamma-ray burst SNe are the most luminous subtypes with a combined median L
p, in erg s−1, of log(L
p) = 43.00 compared to 42.51 for SNe Ic, 42.50 for SNe Ib, and 42.36 for SNe IIb. It is also found that SNe Ic-BL synthesize approximately twice the amount of 56Ni compared with SNe Ic, Ib, and IIb, with median M
Ni = 0.34, 0.16, 0.14, and 0.11 M⊙, respectively. SNe Ic-BL, and to a lesser extent SNe Ic, typically rise from L
p/2 to L
p more quickly than SNe Ib/IIb; consequently, their light curves are not as broad.
Grains are the main energy and carbohydrate sources for human nutrition globally. Governmental and non-governmental authorities recommend whole grains as a healthy food choice. The role of ...contaminants in (whole) grains and how to mitigate any potential risk following their consumption has not been reported. With this narrative review, we shed light on the potential human health risk from contaminants in whole grains and elaborate strategies to mitigate such risk. We found that grains represent a significant source of food-borne contaminants, the main ones being; mycotoxins including (A) aflatoxin B1; (B) ochratoxin A; (C) fumonisin B1; (D) deoxynivalenol; (E) zearalenone; toxic metals like arsenic, cadmium and lead; as well as process contaminants such as acrylamide. Whole grains usually contain more contaminants than refined products. However, whole grains also provide more nutrients that may reduce the impact of these contaminants. Strict regulatory thresholds aim to minimize the risk of contaminants to public health. The consumer can further impact on the mitigation of any risk by eating a healthy diet filled with nutrient-dense foods such as whole grains and probiotics. The risk posed by contaminants from whole grains do not outweigh the known nutritional benefits of whole grain consumption.
ABSTRACT We present ultraviolet through near-infrared photometry and spectroscopy of the host galaxies of all superluminous supernovae (SLSNe) discovered by the Palomar Transient Factory prior to ...2013 and derive measurements of their luminosities, star formation rates, stellar masses, and gas-phase metallicities. We find that Type I (hydrogen-poor) SLSNe (SLSNe I) are found almost exclusively in low-mass ( ) and metal-poor (12 + log10O/H ) galaxies. We compare the mass and metallicity distributions of our sample to nearby galaxy catalogs in detail and conclude that the rate of SLSNe I as a fraction of all SNe is heavily suppressed in galaxies with metallicities . Extremely low metallicities are not required and indeed provide no further increase in the relative SLSN rate. Several SLSN I hosts are undergoing vigorous starbursts, but this may simply be a side effect of metallicity dependence: dwarf galaxies tend to have bursty star formation histories. Type II (hydrogen-rich) SLSNe (SLSNe II) are found over the entire range of galaxy masses and metallicities, and their integrated properties do not suggest a strong preference for (or against) low-mass/low-metallicity galaxies. Two hosts exhibit unusual properties: PTF 10uhf is an SLSN I in a massive, luminous infrared galaxy at redshift z = 0.29, while PTF 10tpz is an SLSN II located in the nucleus of an early-type host at z = 0.04.
Variable x-ray and γ-ray emission is characteristic of the most extreme physical processes in the universe. We present multiwavelength observations of a unique γ-ray—selected transient detected by ...the Swift satellite, accompanied by bright emission across the electromagnetic spectrum, and whose properties are unlike any previously observed source. We pinpoint the event to the center of a small, star-forming galaxy at redshift z = 0.3534. Its high-energy emission has lasted much longer than any γ-ray burst, whereas its peak luminosity was ∼100 times higher than bright active galactic nuclei. The association of the outburst with the center of its host galaxy suggests that this phenomenon has its origin in a rare mechanism involving the massive black hole in the nucleus of that galaxy.
We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations. This ...'Union' compilation of 414 SNe Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older data sets, as well as the recently extended data set of distant supernovae observed with the Hubble Space Telescope (HST). A single, consistent, and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers. We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO). The constraint we obtain from supernovae on the dark energy density is image, for a flat, Lambda CDM universe. Assuming a constant equation of state parameter, w, the combined constraints from SNe, BAO, and CMB give image. While our results are consistent with a cosmological constant, we obtain only relatively weak constraints on a w that varies with redshift. In particular, the current SN data do not yet significantly constrain w at image. With the addition of our new nearby Hubble-flow SNe Ia, these resulting cosmological constraints are currently the tightest available.
Hubble Space Telescope spectroscopic observations of the nearby Type Ia supernova (SN Ia) SN 2011fe, taken on 10 epochs from −13.1 to +40.8 d relative to B-band maximum light, and spanning the ...far-ultraviolet (UV) to the near-infrared (IR) are presented. This spectroscopic coverage makes SN 2011fe the best-studied local SN Ia to date. SN 2011fe is a typical moderately luminous SN Ia with no evidence for dust extinction. Its near-UV spectral properties are representative of a larger sample of local events (Maguire et al.). The near-UV to optical spectra of SN 2011fe are modelled with a Monte Carlo radiative transfer code using the technique of 'abundance tomography', constraining the density structure and the abundance stratification in the SN ejecta. SN 2011fe was a relatively weak explosion, with moderate Fe-group yields. The density structures of the classical model W7 and of a delayed detonation model were tested. Both have shortcomings. An ad hoc density distribution was developed which yields improved fits and is characterized by a high-velocity tail, which is absent in W7. However, this tail contains less mass than delayed detonation models. This improved model has a lower energy than one-dimensional explosion models matching typical SNe Ia (e.g. W7, WDD1; Iwamoto et al.). The derived Fe abundance in the outermost layer is consistent with the metallicity at the SN explosion site in M101 (∼0.5 Z). The spectroscopic rise-time (∼19 d) is significantly longer than that measured from the early optical light curve, implying a 'dark phase' of ∼1 d. A longer rise-time has significant implications when deducing the properties of the white dwarf and binary system from the early photometric behaviour.
We present a radio-quiet quasar at z = 0.237 discovered "turning on" by the intermediate Palomar Transient Factory (iPTF). The transient, iPTF 16bco, was detected by iPTF in the nucleus of a galaxy ...with an archival Sloan Digital Sky Survey spectrum with weak narrow-line emission characteristic of a low-ionization nuclear emission-line region (LINER). Our follow-up spectra show the dramatic appearance of broad Balmer lines and a power-law continuum characteristic of a luminous ( erg s−1) type 1 quasar 12 yr later. Our photometric monitoring with PTF from 2009-2012 and serendipitous X-ray observations from the XMM-Newton Slew Survey in 2011 and 2015 constrain the change of state to have occurred less than 500 days before the iPTF detection. An enhanced broad H /O iii λ5007 line ratio in the type 1 state relative to other changing-look quasars also is suggestive of the most rapid change of state yet observed in a quasar. We argue that the >10 increase in Eddington ratio inferred from the brightening in UV and X-ray continuum flux is more likely due to an intrinsic change in the accretion rate of a preexisting accretion disk than an external mechanism such as variable obscuration, microlensing, or the tidal disruption of a star. However, further monitoring will be helpful in better constraining the mechanism driving this change of state. The rapid "turn-on" of the quasar is much shorter than the viscous infall timescale of an accretion disk and requires a disk instability that can develop around a black hole on timescales less than 1 yr.
ABSTRACT
We present measurements of the local core-collapse supernova (CCSN) rate using SN discoveries from the Palomar Transient Factory (PTF). We use a Monte Carlo simulation of hundreds of ...millions of SN light-curve realizations coupled with the detailed PTF survey detection efficiencies to forward model the SN rates in PTF. Using a sample of 86 CCSNe, including 26 stripped-envelope SNe (SESNe), we show that the overall CCSN volumetric rate is $r^\mathrm{CC}_v=9.10_{-1.27}^{+1.56}\times 10^{-5}\, \text{SNe yr}^{-1}\, \text{Mpc}^{-3}\, h_{70}^{3}$ at 〈z〉 = 0.028, and the SESN volumetric rate is $r^\mathrm{SE}_v=2.41_{-0.64}^{+0.81}\times 10^{-5}\, \text{SNe yr}^{-1}\, \text{Mpc}^{-3}\, h_{70}^{3}$. We further measure a volumetric rate for hydrogen-free superluminous SNe (SLSNe-I) using eight events at z ≤ 0.2 of $r^\mathrm{SLSN-I}_v=35_{-13}^{+25}\, \text{SNe yr}^{-1}\text{Gpc}^{-3}\, h_{70}^{3}$, which represents the most precise SLSN-I rate measurement to date. Using a simple cosmic star formation history to adjust these volumetric rate measurements to the same redshift, we measure a local ratio of SLSN-I to SESN of ${\sim}1/810^{+1500}_{-94}$, and of SLSN-I to all CCSN types of ${\sim}1/3500^{+2800}_{-720}$. However, using host galaxy stellar mass as a proxy for metallicity, we also show that this ratio is strongly metallicity dependent: in low-mass (logM* < 9.5 M⊙) galaxies, which are the only environments that host SLSN-I in our sample, we measure an SLSN-I to SESN fraction of $1/300^{+380}_{-170}$ and $1/1700^{+1800}_{-720}$ for all CCSN. We further investigate the SN rates a function of host galaxy stellar mass, and show that the specific rates of all CCSNe decrease with increasing stellar mass.
We present photometric and spectroscopic observations of SN 2007if, an overluminous (M_V = -20.4), red (B-V = 0.16 at B-band maximum), slow-rising (t_rise = 24 days) type Ia supernova in a very faint ...(M_g = -14.10) host galaxy. A spectrum at 5 days past B-band maximum light is a direct match to the super-Chandrasekhar-mass candidate SN Ia 2003fg, showing Si II and C II at ~9000 km/s. A high signal-to-noise co-addition of the SN spectral time series reveals no Na I D absorption, suggesting negligible reddening in the host galaxy, and the late-time color evolution has the same slope as the Lira relation for normal SNe Ia. The ejecta appear to be well mixed, with no strong maximum in I-band and a diversity of iron-peak lines appearing in near-maximum-light spectra. SN2007 if also displays a plateau in the Si II velocity extending as late as +10 days, which we interpret as evidence for an overdense shell in the SN ejecta. We calculate the bolometric light curve of the SN and use it and the \ion{Si}{2} velocity evolution to constrain the mass of the shell and the underlying SN ejecta, and demonstrate that SN2007 if is strongly inconsistent with a Chandrasekhar-mass scenario. Within the context of a "tamped detonation" model appropriate for double-degenerate mergers, and assuming no host extinction, we estimate the total mass of the system to be 2.4 +/- 0.2 solar masses, with 1.6 +/- 0.1 solar masses of nickel-56 and with 0.3-0.5 solar masses in the form of an envelope of unburned carbon/oxygen. Our modeling demonstrates that the kinematics of shell entrainment provide a more efficient mechanism than incomplete nuclear burning for producing the low velocities typical of super-Chandrasekhar-mass SNeIa.
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