Comparison of the effects of high and low milk-replacer feeding regimens on health and growth of crossbred dairy heifers

Context: Pre-weaning growth in dairy heifers is highly dependent on the amount of milk fed. Both milk replacer (MR) and associated labour are costly, encouraging restricted milk rations and once-a-day feeding. Aims: This study compared performance relating to the growth and health of calves receiving one of two commercial feeding regimens: High or Low. Methods: All heifers born during the Spring (January–March) calving block on a commercial UK farm with mixed-breed genetics were recruited at birth, randomly assigned to the High (n = 104, receiving MR-A) or Low (n = 88, receiving MR-B) feed group and reared indoors on straw bedding, with free access to concentrate. Both groups initially received MR twice daily. The High group continued to receive MR twice daily throughout the experiment, whereas the Low group calves were reduced to a single MR feed daily during Weeks 4–8. Blood samples were taken in Weeks 1 and 6 to assess passive transfer and measure circulating insulin-like growth factor 1 (IGF1). The Wisconsin calf-scoring system was used to assess health of calves in Weeks 1, 2, 4, 6 and 8 and at 6 months and size was also measured at these times. Data were analysed by univariate and multivariate models. Key results: Passive transfer was good in both groups (serum total protein (mean ± s.d.) 60.9 ± 9.1 mg/mL) with no differences in pre-weaning disease incidence; diarrhoea occurred in 64.5% and bovine respiratory disease in 26.3% of calves. High group calves were significantly heavier, taller and longer at all pre-weaning examinations except recruitment owing to more growth in the first month, and remained significantly larger at 6 months: weight 157 ± 8 vs 149 ± 7 kg, height 103 ± 5 vs 100 ± 5 cm, length 90 ± 4 vs 88 ± 5 cm. Plasma IGF1 concentrations at around Week 6 were doubled in the High group (101 ± 38.6 vs 55 ± 34.1 ng/mL). Bovine respiratory disease was associated with reduced weight gain. Heifers with diarrhoea were leaner at weaning. High feed group, weight at recruitment and good passive transfer were positively associated with weight at 6 months. Conclusions: Higher feeding levels pre-weaning increased growth rates and IGF1, although the disease incidence was unaffected. Implications: Previous studies have shown that more growth and higher IGF1 pre-weaning are associated with a lower age at first calving and an increased chance of reaching the end of first lactation. These in turn improve long-term performance

Fish powder as a low-cost component in media for producing bacterial cellulose

Some bacteria can produce extracellular bacterial cellulose (BC). This polysaccharide is chemically identical to cellulose produced by plants but has no associated lignin and hemicelluloses. The unique mechanical properties, chemical stability and purity allow BC to be exploited for a range of biomedical applications. However, medium costs limit commercial BC production. The suitability of using fish powder as a low-cost media component for producing BC by submerged culture of Gluconacetobacter xylinus in shake flasks was investigated. Fish powder was made by drying and grinding Koi carp (Cyprinus carpio), a pest fish in New Zealand waterways. Fermentations were done at 30oC in a growth medium containing 50 g/L glucose, the required minerals, and either 5 g/L yeast extract or 15 g/L fish powder, The BC yield on both yeast extract and fish powder was 0.04 g/g glucose, demonstrating fish powder was a suitable low cost ingredient for supplying nitrogen and amino acids in the media

Predictive haemodynamics in a one-dimensional human carotid artery bifurcation. Part II: application to graft design

A Bayesian surrogate modelling technique is proposed that may be able to predict an optimal bypass graft configuration for patients suffering with stenosis in the internal carotid artery (ICA). At the outset, this statistical technique is considered as a means for identifying key geometric parameters influencing haemodynamics in the human carotid bifurcation. This methodology uses a design of experiments (DoE) technique to generate candidate geometries for flow analysis. A pulsatile one dimensional Navier-Stokes solver incorporating fluid-wall interactions for a Newtonian fluid which predicts pressure and flow in the carotid bifurcation (comprising a stenosed segment in the internal carotid artery) is used for the numerical simulations. Two metrics, pressure variation factor (PVF) and maximum pressure (pm) are employed to directly compare the global and local effects, respectively, of variations in the geometry. The values of PVF and pm are then used to construct two Bayesian surrogate models. These models are statistically analysed to visualise how each geometric parameter influences PVF and pm. Percentage of stenosis is found to influence these pressure based metrics more than any other geometric parameter. Later, we identify bypass grafts with optimal geometric and material properties which have low values of PVF on five test cases with 70%, 75%, 80%, 85% and 90% stenosis in the ICA, respectively

The Latin Leaflet, Number 29

Polymer electrolytes represent the ultimate in terms of desirable properties of energy storage/conversion devices, as they can offer an all-solid-state construction, a wide variety of shapes and sizes, light-weight, low costs, high energy density and safety. Here we present our recent results concerning a novel strategy for preparing efficient polymer membranes which are successfully demonstrated as suitable electrolytes for several energy conversion and storage devices (i.e., Li- and Na-based batteries and DSSCs). Highly ionic conducting polymer electrolytes containing PEO-based functionalities and different components (e.g., Li/Na salts, RTILs, natural biosourced and cellulosic fillers) are successfully prepared via a rapid process and, directly or subsequently, cross-linked via UV irradiation (patent pending, PCT/IT2014/000008). All the prepared materials are thoroughly characterised in terms of their physical, chemical and morphological properties and tested for their electrochemical performances and durability. The UV-curing process on such materials led to the production of elastic and resistant amorphous macromolecular networks. Noticeably increased ionic conductivities are registered (10-3 S cm-1 at RT), along with very stable interfacial and storage stability and wide electrochemical stability windows. The different lab-scale solid-state devices show remarkable performances even at ambient temperature, at the level of those using liquid electrolytes, respect to which demonstrate much greater durability and safety. The obtained findings demonstrate a new, easy and low cost approach to fabricate and tailor-make polymer electrolytes with highly promising prospects for the next generation of advanced flexible energy production and storage devices

Ferromagnetism and the Effect of Free Charge Carriers on Electric Polarization in Y_2NiMnO_6 Double Perovskite

The double perovskite Y_2NiMnO_6 displays ferromagnetic transition at Tc = 81 K. The ferromagnetic order at low temperature is confirmed by the saturation value of magnetization (M_s) and also, validated by the refined ordered magnetic moment values extracted from neutron powder diffraction data at 10 K. This way, the dominant Mn4+ and Ni2+ cationic ordering is confirmed. The cation-ordered P 21/n nuclear structure is revealed by neutron powder diffraction studies at 300 and 10 K. Analysis of frequency dependent dielectric constant and equivalent circuit analysis of impedance data takes into account the bulk contribution to total dielectric constant. This reveals an anomaly which coincides with the ferromagnetic transition temperature (T_c). Pyrocurrent measurements register a current flow with onset near Tc and a peak at 57 K that shifts with temperature ramp rate. The extrinsic nature of the observed pyrocurrent is established by employing a special protocol measurement. It is realized that the origin is due to re-orientation of electric dipoles created by the free charge carriers and not by spontaneous electric polarization at variance with recently reported magnetism-driven ferroelectricity in this materialComment: Published in Physical Review

File Fragmentation over an Unreliable Channel

It has been recently discovered that heavy-tailed file completion time can result from protocol interaction even when file sizes are light-tailed. A key to this phenomenon is the RESTART feature where if a file transfer is interrupted before it is completed, the transfer needs to restart from the beginning. In this paper, we show that independent or bounded fragmentation guarantees light-tailed file completion time as long as the file size is light-tailed, i.e., in this case, heavy-tailed file completion time can only originate from heavy-tailed file sizes. If the file size is heavy-tailed, then the file completion time is necessarily heavy-tailed. For this case, we show that when the file size distribution is regularly varying, then under independent or bounded fragmentation, the completion time tail distribution function is asymptotically upper bounded by that of the original file size stretched by a constant factor. We then prove that if the failure distribution has non-decreasing failure rate, the expected completion time is minimized by dividing the file into equal sized fragments; this optimal fragment size is unique but depends on the file size. We also present a simple blind fragmentation policy where the fragment sizes are constant and independent of the file size and prove that it is asymptotically optimal. Finally, we bound the error in expected completion time due to error in modeling of the failure process