The effect of age on the carcass composition, portion yield and proximate composition of two rabbit genetic types in South Africa

[EN] This study investigated the carcass component yields and meat proximate composition of 2 rabbit genetic types (Californian and hybrid New Zealand Red×Californian), with 5 rabbits per genetic type being slaughtered every 2 wk throughout the study period (9-17 wk) to evaluate the effect of age on these traits. Slaughter weight, reference yield, portion yield (hind leg, foreleg and fore part, as percentage of slaughter weight), meat yield, skin weight and the fat content of the meat (percentage of wet weight) increased significantly with age, while the full gastrointestinal tract, liver, head and feet decreased significantly. This is likely a reflection of the early-maturing nature of bone and viscera and later maturing nature of muscle and fat. These results indicate that delaying slaughter to 13 wk tends to improve yields for valuable carcass components. The Californian had a significantly higher total meat yield at 11 and 17 wk and higher portion meat yields at 9 (hind leg), 11 (hind leg and fore part) and 13 (foreleg) weeks than the hybrid. This was likely due to the later maturation of the hybrid and the influence of the New Zealand Red on carcass quality. It therefore appears that the Californian may be more favourable for meat production, from a carcass and meat quality perspective.The authors would like to thank Gail Jordaan from the Department of Animal Sciences at Stellenbosch University for performing the statistical analysis of the data. This work is based on research supported by the South African Research Chairs Initiative of the Department of Science and Technology and the National Research Foundation of South Africa. Any opinion, finding and conclusion or recommendation expressed in this material is that of the author(s) and the National Research Foundation does not accept any liability in this regard.North, M.; Nkhabutlane, P.; Hoffman, L. (2017). The effect of age on the carcass composition, portion yield and proximate composition of two rabbit genetic types in South Africa. World Rabbit Science. 25(3):281-288. https://doi.org/10.4995/wrs.2017.6396SWORD28128825

Thixotropy in macroscopic suspensions of spheres

An experimental study of the viscosity of a macroscopic suspension, i.e. a suspension for which Brownian motion can be neglected, under steady shear is presented. The suspension is prepared with a high packing fraction and is density-matched in a Newtonian carrier fluid. The viscosity of the suspension depends on the shear rate and the time of shearing. It is shown for the first time that a macroscopic suspension shows thixotropic viscosity, i.e. shear-thinning with a long relaxation time as a unique function of shear. The relaxation times show a systematic decrease with increasing shear rate. These relaxation times are larger when decreasing the shear rates, compared to those observed after increasing the shear. The time scales involved are about 10000 times larger than the viscous time scale and about 1000 times smaller than the thermodynamic time scale. The structure of the suspension at the outer cylinder of a viscometer is monitored with a camera, showing the formation of a hexagonal structure. The temporal decrease of the viscosity under shear coincides with the formation of this hexagonal pattern

The Paradox of Muscle Hypertrophy in Muscular Dystrophy

Mutations in the dystrophin gene cause Duchenne and Becker muscular dystrophy in humans and syndromes in mice, dogs, and cats. Affected humans and dogs have progressive disease that leads primarily to muscle atrophy. Mdx mice progress through an initial phase of muscle hypertrophy followed by atrophy. Cats have persistent muscle hypertrophy. Hypertrophy in humans has been attributed to deposition of fat and connective tissue (pseudohypertrophy). Increased muscle mass (true hypertrophy) has been documented in animal models. Muscle hypertrophy can exaggerate postural instability and joint contractures. Deleterious consequences of muscle hypertrophy should be considered when developing treatments for muscular dystrophy

Effect of an Electron-phonon Interaction on the One-electron Spectral Weight of a d-wave Superconductor

We analyze the effects of an electron-phonon interaction on the one-electron spectral weight A(k,omega) of a d_{x^2-y^2} superconductor. We study the case of an Einstein phonon mode with various momentum-dependent electron-phonon couplings and compare the structure produced in A(k,omega) with that obtained from coupling to the magnetic pi-resonant mode. We find that if the strength of the interactions are adjusted to give the same renormalization at the nodal point, the differences in A(k,omega) are generally small but possibly observable near k=(pi,0).Comment: 10 pages, 14 figures (color versions of Figs. 2,4,10,11,12 available upon request

Mucin concentrations and peripheral airway obstruction in chronic obstructive pulmonary disease

Recent studies have revealed that increased airway mucin concentrations in chronic obstructive pulmonary disease (COPD) slow mucociliary clearance and produce mucus adhesion with mucus plug formation (1). Furthermore, data from SPIROMICS (Subpopulations and Intermediate Outcomes in COPD Study) demonstrated an association between induced sputum (IS) mucin concentrations and measures of airflow obstruction, e.g., FEV1 and FEV1/FVC (2). Peripheral airways are the earliest and dominant sites of airflow obstruction in COPD, and Hogg and colleagues demonstrated that intraluminal mucus plugs contribute a major component to peripheral airway obstruction (3). For development of targeted therapies, it is important to understand whether there are associations between mucus concentrations and peripheral airway obstruction in COPD

Marijuana use associations with pulmonary symptoms and function in Tobacco smokers enrolled in the Subpopulations and Intermediate Outcome Measures in COPD study (SPIROMICS)

Background: Marijuana is often smoked via a filterless cigarette and contains similar chemical makeup as smoked tobacco. There are few publications describing usage patterns and respiratory risks in older adults or in those with chronic obstructive pulmonary disease (COPD). Methods: A cross-sectional analysis of current and former tobacco smokers from the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) study assessed associations between marijuana use and pulmonary outcomes. Marijuana use was defined as never, former (use over 30 days ago), or current (use within 30 days). Respiratory health was assessed using quantitative high-resolution computed tomography (HRCT) scans, pulmonary function tests and questionnaire responses about respiratory symptoms. Results: Of the total 2304 participants, 1130 (49%) never, 982 (43%) former, and 192 (8%) current marijuana users were included. Neither current nor former marijuana use was associated with increased odds of wheeze (odds ratio [OR] 0.87, OR 0.97), cough (OR 1.22; OR 0.93) or chronic bronchitis (OR 0.87; OR 1.00) when compared to never users. Current and former marijuana users had lower quantitative emphysema (P=0.004, P=0.03), higher percent predicted forced expiratory volume in 1 second (FEV1%) (P < 0.001, P < 0.001), and percent predicted forced vital capacity (FVC%) (p < 0.001, P < 0.001). Current marijuana users exhibited higher total tissue volume (P=0.003) while former users had higher air trapping (P < 0.001) when compared to never marijuana users. Conclusions: Marijuana use was found to have little to no association with poor pulmonary health in older current and former tobacco smokers after adjusting for covariates. Higher forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) was observed among current marijuana users. However, higher joint years was associated with more chronic bronchitis symptoms (e.g., wheeze), and this study cannot determine if long-term heavy marijuana smoking in the absence of tobacco smoking is associated with lung symptoms, airflow obstruction, or emphysema, particularly in those who have never smoked tobacco cigarettes

Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV

We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [-1.3, 1.3]. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.Comment: 6 pages, 3 figure

Measurement of the Bottom contribution to non-photonic electron production in p+pp+p collisions at s\sqrt{s} =200 GeV

The contribution of $B$ meson decays to non-photonic electrons, which are mainly produced by the semi-leptonic decays of heavy flavor mesons, in $p+p$ collisions at $\sqrt{s} =$ 200 GeV has been measured using azimuthal correlations between non-photonic electrons and hadrons. The extracted $B$ decay contribution is approximately 50% at a transverse momentum of $p_{T} \geq 5$ GeV/$c$. These measurements constrain the nuclear modification factor for electrons from $B$ and $D$ meson decays. The result indicates that $B$ meson production in heavy ion collisions is also suppressed at high $p_{T}$.Comment: 6 pages, 4 figures, accepted by PR