On-the-fly reduction of open loops

Building on the open-loop algorithm we introduce a new method for the automated construction of one-loop amplitudes and their reduction to scalar integrals. The key idea is that the factorisation of one-loop integrands in a product of loop segments makes it possible to perform various operations on-the-fly while constructing the integrand. Reducing the integrand on-the-fly, after each segment multiplication, the construction of loop diagrams and their reduction are unified in a single numerical recursion. In this way we entirely avoid objects with high tensor rank, thereby reducing the complexity of the calculations in a drastic way. Thanks to the on-the-fly approach, which is applied also to helicity summation and for the merging of different diagrams, the speed of the original open-loop algorithm can be further augmented in a very significant way. Moreover, addressing spurious singularities of the employed reduction identities by means of simple expansions in rank-two Gram determinants, we achieve a remarkably high level of numerical stability. These features of the new algorithm, which will be made publicly available in a forthcoming release of the OpenLoops program, are particularly attractive for NLO multi-leg and NNLO real-virtual calculations.Comment: v2 as accepted by EPJ C: extended discussion of the triangle reduction and its numerical stability in section 5.4.2; speed benchmarks for 2->5 processes included in section 6.2.1; ref. adde

Effect of chestnut tannin in the diet of lactating ewes on milk and cheese quality

A commercial product consisting of pure soluble tannins extracted from chestnut wood was introduced into the diet of lactating ewes at pasture, at the level of 20 g / head / day in the concentrate mixed feed. The supplementation with tannins did not exert any influence on milk yield and on lactose and fat content of milk, but induced an increase in milk protein yield, apparently in heat coagulable proteins. This is maybe due to an increase of the rumen undegradable fraction of dietary proteins. The somatic cells count and the bacterial load of milk were not affected as well. Further studies are needed to confirm these important results, in order to optimize the nitrogen metabolic balance of ruminant animals, among the other advantages

Neutral Detergent Fibre (NDF) and Non Structural Carbohydrate (NSC) requirements in the nutrition of dairy ewes

The aim of this review was to contribute to the knowledge of neutral detergent fibre (NDF) and non structural carbo- hydrate (NSC) requirements in the nutrition of dairy ewes. NDF and NSC requirements were evaluated by analysing a dataset that involved 30 experimental trials carried out from 1985 to 2003. The dataset included chemical composition of the experimental diets, individual milk yield, body weight, milk protein and fat content. These selected papers regard 10 different dairy ewe breeds (Valle del Belice, Bergamasca, Comisana, Delle Langhe, Massese, Sarda, Chios, Manchega, Lacaune and Friesian) and lactating ewes in mid lactation, kept under non homogeneous environmental and feeding conditions. Results substantially confirmed that which was recently reported in literature: NDF requirements are higher in late lactation than during early lactation and they vary between 33-38% on DM, while NSC requirements are higher during early lactation than in late lactation when the energy from NSC promotes an increase in fat deposits

Lipid requirements in the nutrition of dairy ewes

The aim of this review was to contribute to the knowledge of lipid requirements in dairy ewes, by reviewing experi- mental papers about lipid supplementation in dairy ewe feeding. The number of trials in ewe feeding is lower than that in dairy cow feeding and, leaving calcium soap of palm oil out of consideration, there is a lack of knowledge regarding the effects of protected and unprotected lipid sources on milk yield and quality from dairy ewes. On the basis of data reported in the literature, the optimal dose of calcium soap of palm oil resulted to be 100-120 g/d. Also, milk fatty acid composition may be improved by adding calcium soap of fatty acids to ewe diets. The general effect of calcium salt sup- plementation is an increase in milk unsaturated fatty acids and a decrease in saturated ones. However, more research is needed in order to explain the effect of different fat sources (protected and unprotected) on milk yield and quality from dairy ewes

Estimated requirements of net energy, digestible protein and NDF intake of young Chianina bulls from 400 kg liveweight to slaughter

Three equations have been elaborated and proposed to predict the requirements of net energy and protein digestible in the intestine and NDF voluntary intake of growing young Chianina bulls, starting from 400 kg live weight. The animals examined in the present study were 100 young Chianina bulls starting from about 400 kg live weight, at 10 months of age, up to the average slaughter weight of 800 kg at 20 months average age. The diet was based on hay and concentrates. The equation for the prediction of net energy fits quite perfectly to another experimental equation formerly proposed by Giorgetti and is characterised by a very high value of the correlation coefficient for the regression comparison between observed and predicted figures (R2=0.90). The statistical reliance degree of the PDIN prediction equation is lower, but still very good (R2=0.75 between observed and predicted values), but that of the estimate of NDF daily intake resulted very poor (R2=0.26 between observed and predicted values), probably due to the non homogeneity of the intake capacity of the 100 examined animals. The correlation between daily gains and the concentration of NDF in the diet DM results good (R2=0.87), showing that young Chianina bulls take advantage of the diet fibre. Further useful indications on the nutritional and dietary requirements of young Chianina bulls are added to the scarce information currently available

Effect of total proteosopeptone content on the variability of bovine milk foaming property

Several authors demonstrated a strong linkage between proteose-peptones content and foaming properties of cow milk; this is of great interest for Italian dairy industries to create a new line of fresh milk characterized by a particular foaming property and, hence, particularly appreciate in catering industry. The aim of this trial was to quantify the relation between total concentration of proteose-peptones and the entity of foaming attitude in cow fresh milk. Ninety samples of raw bulk milk were analysed for proteose-peptones content, plasmin activity, fatty acid profile and foaming attitude. A negative relation was found among proteose-peptones percentage and foaming attitude which decreased with the increase of plasmin activity and somatic cell content in milk

Use of a citrus by-product in broilers diets

The European Union is about to ban antibiotics as growth promoters in animal feeds. Organic products have been recently revalued and the animal science research showed a great interest in the study of alternative natural nutraceutical products in animal feeding. Flavonoids are plant pigments able to inhibit or kill many bacterial strains, to destroy some pathogenic protozoa and to scavenge free radicals