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Three supernovae have so far been detected in the radio range shortly after their optical outbursts. All are Type IIs. A fourth supernova, a Type I, is being monitored for radio emission but, at an age of approximately one year, has not yet been detected. For two of the supernovae, extensive data are presented on their “light curves” and spectra and models which have been suggested in the literature are discussed.
At the lowest radio frequencies (≤30 MHz), the Earth's ionosphere transmits poorly or not at all. This relatively unexplored region of the electromagnetic spectrum is thus an area where high resolution, high sensitivity observations can open a new window for astronomical investigations. Also, extending observations down to very low frequencies brings astronomy to a fundamental physical limit where the Milky Way becomes optically thick over relatively short path lengths due to diffuse free-free absorption.
Snapshot VLBI observations at 18 cm have been obtained with a global array at three epochs (1980.1, 1981.8, 1987.9) in order to investigate flux density and/or structural variations for a sample of 21 low frequency variable sources (Padrielli et al. 1987 Astron Astrophys. Suppl. Ser., 67, 63; Bondi et al. 1993 in preparation).
We report on 74 MHz and 330 MHz VLA observations of the plerionic supernova remnant 3C58. The radio spectral index, α, is uniform across the remnant to within 0.18, indicating a single source for the accelerated electrons. We find no emission from any shell surrounding the remnant. Our 3σ brightness limit on shell emission surrounding 3C58 is < 1.3×10−21 W m−2 Hz−1 sr−1 at 330 MHz.
Whether supplemental Ca has similar effects to dietary Ca on vascular and bone markers is unknown. The present trial investigated the feasibility of applying dietary and supplemental interventions in a randomised-controlled trial (RCT) aiming to estimate the effect of supplemental Ca as compared with dietary Ca on vascular and bone markers in postmenopausal women. In total, thirteen participants were randomised to a Ca supplement group (CaSuppl) (750 mg Ca from CaCO3+450 mg Ca from food+20 µg vitamin D supplement) or a Ca diet group (CaDiet) (1200 mg Ca from food+10 µg vitamin D supplement). Participants were instructed on Ca consumption targets at baseline. Monthly telephone follow-ups were conducted to assess adherence to interventions (±20 % of target total Ca) using the multiple-pass 24-h recall method and reported pill count. Measurements of arterial stiffness, peripheral blood pressure and body composition were performed at baseline and after 6 and 12 months in all participants who completed the trial (n 9). Blood and serum biomarkers were measured at baseline and at 12 months. Both groups were compliant to trial interventions (±20 % of target total Ca intake; pill count ≥80 %). CaSuppl participants maintained a significantly lower average dietary Ca intake compared with CaDiet participants throughout the trial (453 (sd 187) mg/d v. 1241 (sd 319) mg/d; P<0·001). There were no significant differences in selected vascular outcomes between intervention groups over time. Our pilot trial demonstrated the feasibility of conducting a large-scale RCT to estimate the differential effects of supplemental and dietary Ca on vascular and bone health markers in healthy postmenopausal women.
The objective of the present study was to determine if vitamin D intake and status are associated with pre-eclampsia in a country without a vitamin D fortification policy.
A case–control study of pregnancies with (case) and without (control) pre-eclampsia was conducted from January to April when UVB is minimal. Maternal and cord blood obtained at delivery were measured for plasma 25-hydroxycholecalciferol (25-OH-D3), 3-epimer of 25-OH-D3 (3-epi-25-OH-D3) and 24,25-dihydroxycholecalciferol (24,25-(OH)2D3) by LC–MS/MS and maternal 1,25-dihydroxyvitamin D (1,25-(OH)2D). Differences between groups were tested with ANOVA and Bonferroni post hoc tests (P<0·05).
Clinical Center of Serbia.
Pregnant women with and without pre-eclampsia (n 60) and their infants.
Exogenous vitamin D intake (0·95–16·25 µg/d (38–650 IU/d)) was not significantly different between groups. Women with pre-eclampsia delivered infants at an earlier gestational age and had significantly lower mean total plasma 25-hydroxyvitamin D (25-OH-D; case: 11·2 (sd 5·1); control: 16·1 (sd 5·7) ng/ml; P=0·0006), 25-OH-D3 (case: 10·0 (sd 4·9); control: 14·2 (sd 5·8) ng/ml; P=0·002), 3-epi-25-OH-D3 (case: 0·5 (sd 0·2); control: 0·7 (sd 0·2) ng/ml; P=0·0007) and 1,25-(OH)2D (case: 56·5 (sd 26·6); control: 81·0 (sd 25·7) pg/ml; P=0·018), while 24,25-(OH)2D3 was not different between groups. Infants did not differ in total plasma 25-OH-D, 25-OH-D3, 3-epi-25-OH-D3 and 24,25-(OH)2D3, but the mean proportion of 3-epi-25-OH-D3 was higher in the infant case group (case: 7·9 (sd 1·1); control: 7·0 (sd 1·4) % of total 25-OH-D3; P=0·005).
A high prevalence of vitamin D deficiency, as defined by plasma 25-OH-D<12 ng/ml, was observed in 47 % of all mothers and 77 % of all infants. These data underscore the need for prenatal vitamin D supplementation and a food fortification policy in Serbia.
The ALFA mission is designed to map the entire sky at frequencies between approximately 0.3 and 30 MHz with angular resolution limited by interstellar and interplanetary scattering. Most of this region of the spectrum is inaccessible from the ground because of absorption and refraction by the Earth’s ionosphere. A wide range of astrophysical questions concerning solar system, galactic, and extragalactic objects could be answered with high resolution images at low frequencies, where absorption effects and coherent emission processes become important and the synchrotron lifetimes of electrons are comparable to the age of the universe.
With new 6 cm observations we confirm the self-similar expansion of SN 1993J previously discovered at 3.6 cm and estimate the expansion deceleration parameter. The results are inconsistent with the existence of a constant pre-explosion stellar wind but otherwise confirm the standard radio supernova model. The first map at 13 cm showing shell structure is also presented.
The supernovae SN1979c in NGC 4321 and SN1980k in NGC 6946 have both been detected at centimeter wavelengths at the VLA. The radio emission turns on very rapidly, but may be delayed by as much as a year with respect to the optical outburst. In both supernovae, the 20 cm radiation peaks after the 6 cm, and the radio emission has a very slow post-maximum decay.
Our team at the University of Barcelona has contributed since the early phases of the mission to the definition, evaluation and calibration modelling of the Gaia photometry. To maximise the Gaia scientific exploitation, we have frequently shared many different tools and data with the astronomical community. Among this information we have defined several relationships among colours involving Gaia magnitudes and colours from other commonly used photometric systems (Johnson-Cousins, SDSS, Hipparcos, Tycho and 2MASS) for several types of stars (including white dwarfs). These relationships can be used for planning scientific exploitation of Gaia data, performing simulations of the Gaia-like sky, planning ground-based complementary observations and for building catalogues with auxiliary validation data. During the commissioning phase our team (as part of the Payload Experts group) has been intensively checking the first photometric data to analyse the health and properties of the real instrument. These preliminary analyses allowed us to monitor the throughput variations with time, assess the spectral resolution and re-evaluate the performances of the end-of-mission photometry. The Payload Experts group activities continue beyond the commissioning phase aiming to optimize the operations onboard for maximizing the scientific return. Some example of first spectra and photometry are shown.
The objective of the present study was to examine the external validity of an FFQ designed to estimate dietary vitamin D intake compared with a plasma biomarker and three repeated 24 h dietary recalls in women of reproductive age in Serbia, where there is no exposure to food fortified with vitamin D. The method of triads was applied.
In a cross-sectional study, 422 women completed the Women and Reproductive Health FFQ (WRH-FFQ) during the winter months. From a representative subgroup (n 44), three 24 h dietary recalls and anthropometric parameters were collected as well as a fasting blood sample for vitamin D biomarker analyses. Correlation coefficients were calculated between each of the dietary methods. Validity coefficients, as a correlation between the measured and estimated ‘true’ exposure, were calculated using the method of triads. Bland–Altman plots were also constructed.
Three major universities in Serbia.
Healthy young women (n 422) aged 18–35 years.
The WRH-FFQ estimate of vitamin D intake for all participants was 4·0 (sd 3·3) µg/d and 3·1 (sd 2·3) µg/d for the subgroup. Bland–Altman plots for these intakes showed high agreement. Validity coefficients for the FFQ, 24 h recall and biomarker were ρQI=0·847 (95 % CI 0·564, 0·928), ρRI=0·810 (95 % CI 0·537, 0·997) and ρBI=0·499 (95 % CI 0·190, 0·840), while the correlation coefficients were 0·686, 0·422 and 0·404.
The FFQ applied in the present study is a valid tool for assessing dietary vitamin D intake in women living in Serbia, a region without mandatory vitamin D food fortification.
Feed intake behavior was studied between 9 weeks of age and slaughter in a total of 36 gilts, 32 immunocastrates, 33 surgically castrated barrows and 33 boars from 36 litters. Consequences for the concentration of substances contributing to off odor of pork (skatole, indole) were evaluated. Animals were kept in groups of 12 pigs of the same sex and treatment and fed ad libitum (13.4 MJ ME, 17% CP, 1.1% lysine). Individual feed intake behavior was recorded continuously by an electronic feeder. Immunocastration was carried out with two injections of Improvac with at least 4 weeks between both injections (1st: 12 to 17 weeks of age, 2nd: 19 to 21 weeks of age). Feed intake/day increased from an average of 0.91 ± 0.02 kg/day up to 3.15 ± 0.04 kg/day before slaughter. This increase was associated with a 50% reduction in the number of meals/day (from 15.8 ± 0.44 to 7.2 ± 0.29 meals/day). The larger meal sizes resulted from an increase in both, the duration of feed intake/meal and the feed intake rate (g/min). In addition, sex and treatment differences were observed: Feed intake in boars was lower than in all other groups due to a reduction in the number of meals/day and in the time spent feeding/day. In females, time spent feeding/day was quite similar to boars, but resulted from a higher number of meals of shorter duration. Barrows had a significantly higher feed intake because of a higher number of meals/day resulting in more time spent feeding/day. The feed intake rate was similar in boars, gilts and barrows and showed an increasing trend during the study, starting from about 15 g/min up to four times the amount. Immunocastration affected feed intake behavior severely, especially the meal size increased dramatically because of higher feed intake rate, which exceeded that of all other groups by 25% at the end of the study. The number of meals/day was not influenced by immunocastration and was almost identical to that of boars. Highest skatole concentrations were measured in fat of boars, whereas indole concentrations were higher in immunocastrates than in all other groups. In gilts and barrows, skatole concentrations were related to growth rate. Additionally, the feeding rate was an important factor explaining the variability in skatole/indole concentrations in adipose tissue. The physiological mechanisms however need further clarification.
In this present work we report the growth of Cd0.9Zn0.1Te doped with In by a modified THM technique. It has been demonstrated that by controlling the microscopically flat growth interface, the size distribution and concentration of Te inclusions can be drastically reduced in the as-grown ingots. This results in as-grown detector-grade CZT by the THM technique. The three-dimensional size distribution and concentrations of Te inclusions/precipitations were studied. The size distributions of the Te precipitations/inclusions were observed to be below the 10-μm range with the total concentration less than 105 cm-3. The relatively low value of Te inclusions/precipitations results in excellent charge transport properties of our as-grown samples. The (μτ)e values for different as-grown samples varied between 6-20 x10-3 cm2/V. The as-grown samples also showed fairly good detector response with resolution of ∼1.5%, 2.7% and about 3.8% at 662 keV for quasi-hemispherical geometry for detector volumes of 0.18 cm3, 1 cm3 and 4.2 cm3, respectively.
High-protein (HP) diets for weight loss remain popular despite questions surrounding overall safety. In a recent study using the pig model, we showed that long-term intakes from whole proteins at 35 % energy (en %) cause moderate renal histological damage. To examine whether this observation may be species specific or more generalisable, the effect of this diet in rats was examined. Using plant and animal whole proteins, 70-d-old female Sprague–Dawley rats were randomised to either a normal-protein (NP; 15 en %) or a HP (35 en %) diet for 4, 8, 12 and 17 months. Renal function was assessed by creatinine clearance and urinary protein levels, and pathology was assessed by examination of glomerular hypertrophy, glomerulosclerosis and tubulointerstitial fibrosis. Rats consuming the HP diet had 17 % higher kidney weights (P < 0·0001), three times higher proteinuria (P < 0·0001) and 27 % higher creatinine clearance (P = 0·0012) compared with those consuming the NP diet. Consistent with this, HP-fed rats had larger glomeruli (P < 0·0001) and more glomerulosclerosis (P = 0·0003) compared with NP-fed rats. The HP diet also resulted in altered levels of free monocyte chemoattractant protein-1 (P < 0·0001). The histological changes are consistent with those observed in the pig model. In contrast to the pig model, the elevated proteinuria and creatinine clearance observed in the rat model are also usually observed with HP consumption in human subjects. These results indicate that the rat is a useful model for HP effects on the kidney and, along with previous results using the pig model, suggest that long-term intake of high levels of protein may be detrimental to renal health.
We present the results of over two decades of radio observations of type IIb Supernovae with the Very Large Array and the Australia Telescope Compact Array. These radio studies illustrate the need for multi-wavelength follow-up to determine the progenitor scenario for type IIb events.
This paper reports recent results on two-layer P-on-n LPE HgCdTe heterojunction photodiodes with cutoff wavelengths beyond 19μm. These results demonstrate the potential of photovoltaic HgCdTe detectors to satisfy the detector requirements of advanced NASA satellite instruments out to wavelengths of 17μm.
The Gaia pixel-level data simulator GIBIS (Gaia Instrument and Basic Image Simulator,
Babusiaux (2005)) provides detailed artificial data for all three instruments on-board the
Gaia spacecraft. This data is used for the preparation of procedures required for the
analysis of real Gaia data to come during the mission. Among the effects that strongly
affect all Gaia data, that therefore have to be modelled with GIBIS, is charge transfer
inefficiency (CTI). CTI, caused by radiation-induced microscopic defects in the CCD
detectors, becomes manifest in a distortion of the line spread functions of observed
objects, as well as in a loss of photo-generated charges inside the window allocated to
each observed source. It affects the astrometric, photometric, and spectroscopic accuracy
of the data. The CTI effects on a particular observation depend on observations done
before, on CCD operations such as gate activity and charge injections, and on physical
effects such as the sky background brightness and cosmic ray events in the detectors. In
this paper, an approach for the simulation of CTI with GIBIS is presented and the
influence of the sky background brightness and cosmic ray events of CTI is discussed in