36 research outputs found
Cosmic Ray Anomalies from the MSSM?
The recent positron excess in cosmic rays (CR) observed by the PAMELA
satellite may be a signal for dark matter (DM) annihilation. When these
measurements are combined with those from FERMI on the total () flux
and from PAMELA itself on the ratio, these and other results are
difficult to reconcile with traditional models of DM, including the
conventional mSUGRA version of Supersymmetry even if boosts as large as
are allowed. In this paper, we combine the results of a previously
obtained scan over a more general 19-parameter subspace of the MSSM with a
corresponding scan over astrophysical parameters that describe the propagation
of CR. We then ascertain whether or not a good fit to this CR data can be
obtained with relatively small boost factors while simultaneously satisfying
the additional constraints arising from gamma ray data. We find that a specific
subclass of MSSM models where the LSP is mostly pure bino and annihilates
almost exclusively into pairs comes very close to satisfying these
requirements. The lightest in this set of models is found to be
relatively close in mass to the LSP and is in some cases the nLSP. These models
lead to a significant improvement in the overall fit to the data by an amount
dof in comparison to the best fit without Supersymmetry
while employing boosts . The implications of these models for future
experiments are discussed.Comment: 57 pages, 31 figures, references adde
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
The genetics of cow growth and body composition at first calving in two tropical beef genotypes
The genetics of cow growth and body composition traits, measured before first calving (pre-calving: in females before calving following their first 3-month annual mating period, at an average age of 34 months) and at the start of the subsequent mating period (Mating 2: on average 109 days later), were evaluated in 1016 Brahman (BRAH) and 1094 Tropical Composite (TCOMP) cows. Measurements analysed were liveweight, ultrasound-scanned measurements of P8 and 12/13th rib fat depth and eye muscle area, body condition score and hip height. Traits describing the change in these from pre-calving to Mating 2 were also included in the analysis. The maternal genetic component of weaning weight was estimated from weaning-weight records on these cows, their steer half-sibs and their progeny generated from up to six matings (n ≤ 12528). Within pregnant cows at pre-calving, BRAH were significantly lighter, leaner at the P8 site and taller than their TCOMP contemporaries, and these differences were also significant at Mating 2. There was a genetic basis for variation in growth and body composition traits measured at pre-calving and Mating 2 in BRAH (h2 ≤ 0.27-0.67) and TCOMP (h2 ≤ 0.25-0.87). Traits describing the change from pre- calving to Mating 2 were also moderately heritable for both genotypes (h2 ≤ 0.17-0.54), except for change in hip height (h2 ≤ 0.00 and 0.10 for BRAH and TCOMP, respectively). Genetic correlations between measurements of the same trait at pre-calving and Mating 2 were consistently positive and strong (rg ≤ 0.75-0.98) and similar for both genotypes. In lactating cows, genetic correlations of growth and body composition traits with their change from pre-calving to Mating 2 showed that when animals had low levels of P8 and rib fat at Mating 2, change in eye muscle area was an important descriptor of genetic body condition score (rg ≤ 0.63). This was supported by moderate genetic relationships, which suggested that lactating cows that were genetically predisposed to lose less eye muscle area were those that ended the period with higher P8 fat (rg ≤ 0.66), rib fat (rg ≤ 0.72) and body condition score (rg ≤ 0.61). Change in liveweight, body condition score and, in particular, eye muscle area was significantly related to the maternal genetic component of weaning weight (rg ≤ from -0.40 to -0.85) in both genotypes, suggesting that cows with higher genetic milk-production potential were those with the propensity for greater loss of these traits over the period from pre-calving to Mating 2. These results showed that for tropically adapted cows, the change in eye muscle area from pre-calving to Mating 2 was a more important descriptor of body condition at Mating 2 than was change in fat depth, and that higher genetic milk-production potential, measured as maternal weaning weight, was genetically related to higher mobilisation of muscle, and therefore body condition, over this period. Journal compilation © CSIRO 2014
Genetics of heifer puberty in two tropical beef genotypes in northern Australia and associations with heifer- and steer-production traits
A total of 2115 heifers from two tropical genotypes (1007 Brahman and 1108 Tropical Composite) raised in four locations in northern Australia were ovarian-scanned every 46 weeks to determine the age at the first-observed corpus luteum (CL) and this was used to define the age at puberty for each heifer. Other traits recorded at each time of ovarian scanning were liveweight, fat depths and body condition score. Reproductive tract size was measured close to the start of the first joining period. Results showed significant effects of location and birth month on the age at first CL and associated puberty traits. Genotypes did not differ significantly for the age or weight at first CL; however, Brahman were fatter at first CL and had a small reproductive tract size compared with that of Tropical Composite. Genetic analyses estimated the age at first CL to be moderately to highly heritable for Brahman (0.57) and Tropical Composite (0.52). The associated traits were also moderately heritable, except for reproductive tract size in Brahmans (0.03) and for Tropical Composite, the presence of an observed CL on the scanning day closest to the start of joining (0.07). Genetic correlations among puberty traits were mostly moderate to high and generally larger in magnitude for Brahman than for Tropical Composite. Genetic correlations between the age at CL and heifer- and steer-production traits showed important genotype differences. For Tropical Composite, the age at CL was negatively correlated with the heifer growth rate in their first postweaning wet season (0.40) and carcass marbling score (0.49), but was positively correlated with carcass P8 fat depth (0.43). For Brahman, the age at CL was moderately negatively genetically correlated with heifer measures of bodyweight, fatness, body condition score and IGF-I, in both their first postweaning wet and second dry seasons, but was positively correlated with the dry-season growth rate. For Brahman, genetic correlations between the age at CL and steer traits showed possible antagonisms with feedlot residual feed intake (0.60) and meat colour (0.73). Selection can be used to change the heifer age at puberty in both genotypes, with few major antagonisms with steer- and heifer-production traits. © 2009 CSIRO
Genetics of early and lifetime annual reproductive performance in cows of two tropical beef genotypes in northern Australia
Reproduction records from 2137 cows first mated at 2 years of age and recorded through to 8.5 years of age were used to study the genetics of early and lifetime reproductive performance from two genotypes (1020 Brahman and 1117 Tropical Composite) in tropical Australian production systems. Regular ultrasound scanning of the reproductive tract, coupled with full recording of mating, calving and weaning histories, allowed a comprehensive evaluation of a range of reproductive traits. Results showed components traits of early reproductive performance had moderate to high heritabilities, especially in Brahmans. The heritability of lactation anoestrous interval in 3-year-old cows was 0.51 ± 0.18 and 0.26 ± 0.11 for Brahman and Tropical Composite, respectively. Heritabilities of binary reproductive output traits (conception rate, pregnancy rate, calving rate and weaning rate) from first and second matings were generally moderate to high on the underlying scale. Estimates ranged from 0.15 to 0.69 in Brahman and 0.15 to 0.34 in Tropical Composite, but were considerably lower when expressed on the observed scale, particularly for those traits with high mean levels. Heritabilities of lifetime reproduction traits were low, with estimates of 0.11 ± 0.06 and 0.07 ± 0.06 for lifetime annual weaning rate in Brahman and Tropical Composite, respectively. Significant differences in mean reproductive performance were observed between the two genotypes, especially for traits associated with anoestrus in first-lactation cows. Genetic correlations between early-in-life reproductive measures and lifetime reproduction traits were moderate to high. Genetic correlations between lactation anoestrous interval and lifetime annual weaning rate were -0.62 ± 0.24 in Brahman and -0.87 ± 0.32 in Tropical Composite. The results emphasise the substantial opportunity that exists to genetically improve weaning rates in tropical beef cattle breeds by focusing recording and selection on early-in-life female reproduction traits, particularly in Brahman for traits associated with lactation anoestrus. Journal compilation © CSIRO 2014
Alpha-1 Antitrypsin MZ Heterozygosity Is an Endotype of Chronic Obstructive Pulmonary Disease
RATIONALE: Multiple studies have demonstrated an increased risk of chronic obstructive pulmonary disease (COPD) in heterozygous carriers of the AAT (alpha-1 antitrypsin) Z allele. However, it is not known if MZ subjects with COPD are phenotypically different from noncarriers (MM genotype) with COPD. OBJECTIVE: To assess if MZ subjects with COPD have different clinical features compared with MM subjects with COPD. METHODS: Genotypes of SERPINA1 were ascertained by using whole-genome sequencing data in three independent studies. We compared outcomes between MM subjects with COPD and MZ subjects with COPD in each study and combined the results in a meta-analysis. We performed longitudinal and survival analyses to compare outcomes in MM and MZ subjects with COPD over time. MEASUREMENTS AND MAIN RESULTS: We included 290 MZ subjects with COPD and 6,184 MM subjects with COPD across the three studies. MZ subjects had a lower FEV1% predicted and greater quantitative emphysema on chest computed tomography scans compared with MM subjects. In a meta-analysis, the FEV1 was 3.9% lower (95% confidence interval [CI], −6.55% to −1.26%) and emphysema (the percentage of lung attenuation areas <−950 HU) was 4.14% greater (95% CI, 1.44% to 6.84%) in MZ subjects. We found one gene, PGF (placental growth factor), to be differentially expressed in lung tissue from one study between MZ subjects and MM subjects. CONCLUSIONS: Carriers of the AAT Z allele (those who were MZ heterozygous) with COPD had lower lung function and more emphysema than MM subjects with COPD. Taken with the subtle differences in gene expression between the two groups, our findings suggest that MZ subjects represent an endotype of COPD