3,239 research outputs found

    Bessel beam through a dielectric slab at oblique incidence: the case of total reflection

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    The oblique incidence of a Bessel beam on a dielectric slab with refractive index n1 surrounded by a medium of a refractive index n>n1 may be studied simply by expanding the Bessel beam into a set of plane waves forming the same angle with the axis of the beam. In the present paper we examine a Bessel beam that impinges at oblique incidence onto a layer in such a way that each plane-wave component impinges with an angle larger than the critical angle.Comment: 10 pages, 6 figure

    A systematic study of laser ablation efficacy as a low-invasive cleaning technique for Cu-based alloys

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    L'abstract è presente nell'allegato / the abstract is in the attachmen

    Effect of Enterococcus faecium SF68 on growth performance and in vivo digestibility in buffalo calves

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    The effect of dietary supplementation with Enterococcus faecium strain SF68 on growth performance, faecal consistency and in vivo digestibility in buffalo (Bubalus bubalis) calves was evaluated. Forty calves were randomly assigned at 10 d of age to one of four treatments: (A) milk replacer with no additive, (B) milk replacer supplemented with 0.17 g/l of viable (2 x l09 cfu/g) E. faecium bacteria daily for 3 days with an interval of 7 days throughout 11 weeks, (C) milk replacer supplemented with E. faecium daily for 4 weeks, (D) milk replacer supplemented with E. faecium daily for 11 weeks. A total mixed ration was offered ad libitum from 5th week of the experimental period. Faecal score was significantly better in E. faecium-treated calves than control ones. The use of E. faecium had no effect on average daily gain at any stage, total body weight (BW) gain, dry matter intake or total tract digestibility. Therefore, E. faecium supplementation may be able to act favourably on the health of the gastro-intestinal trac

    Fatty acid composition of Mediterranean buffalo milk fat

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    The purpose of this research was to investigate the variation in fatty acid composition of milk fat from four buffalo (Bubalus bubalis) herds under different feeding management and ration composition. Changes in milk fatty acid composition were monitored on a weekly basis. Saturated fatty acids (65.5%) predominated in buffalo milk fat; monounsaturated and polyunsaturated fatty acids were 27.0% and 4.5%, respectively. Of saturated fatty acids, the content of palmitic acid was the highest (30.6%) followed by stearic acid (12.0%) and myristic acid (10.7%). Of the unsaturated fatty acids the content of oleic acid was the highest (26.6%). The average content of conjugated linoleic acid (0.76±0.33) was higher than the maximal values generally reported for dairy cow

    Effect of Lupinus albus as protein supplement on yield, constituents, clotting properties and fatty acid composition in ewes' milk

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    The effect of feeding lupin seeds (Lupinus albus L.) as an alternative protein source in ewe diets was investigated. Two groups of 18 Sarda ewes were fed two different isonitrogenous diets: with lupin (L) seed, given after 12 h soaking, or soybean meal (SBM) as the main protein source. DMI, variations of body weight and milk production were unaffected by the treatment. Although not statistically significant, in the group fed L diet the production of milk fat and protein was higher. Clotting properties of milk were similar for the two treatments, probably due to the small differences in the milk protein contents. The fatty acid profile of milk was affected by treatment with a larger content of short (14.19 wt% versus 12.26 wt%)- and medium (49.37 wt% versus 47.76 wt%)-chain fatty acids in milk from ewes fed the L diet. CLA content was unaffected by treatment. Triglyceride content of fat from the two diets reflects the milk fatty acid composition. Indeed, milk from L diet showed a higher level of medium-chain triglycerides, which are of particular interest to consumers with concerns over health and heart disease. The inclusion of lupin seed in the diet of lactation ewes can be a means of achieving a more desirable triglyceride profile in milk fat. Milk with enhanced nutritive quality may promote wider market penetration of sheep dairy products

    Use of peas in organic buffalo farming: effects on nutrient digestibility and milk production

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    Twenty lactating buffalo cows, organically farmed, were used to examine the effects of including peas in total mixed ration. Two concentrates were formulated to contain, as the main protein sources, either 350 g/kg of soybean cake (CC) or 450 g/kg of peas (ExpC). Cows were blocked into two groups according to parity and previous milk yield and were assigned to one of two dietary treatments: one group was fed a diet with 6 kg/d of CC, whereas the treatment group was fed diet in which 3kg/d of CC were replaced by an equal quantity of ExpC. Digestibility of the diets and milk production of the cows were measured. The experimental period covered the whole lactation period. No differences were observed between groups for milk yield and composition, and for total tract apparent digestibility. The main hypothesis tested, that the replacement of soybean cake with peas in buffalo diet would not affect milk yield and composition, was confirmed. This suggested that the partial substitution of soybean cake with peas in diet for buffalo cows can be possible without affect performances

    Estimation of the methane emission factor for the Italian Mediterranean buffalo

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    In order to contribute to the improvement of the national greenhouse gas emission inventory, this work aimed at estimating a country-specific enteric methane (CH4) emission factor for the Italian Mediterranean buffalo. For this purpose, national agriculture statistics, and information on animal production and farming conditions were analysed, and the emission factor was estimated using the Tier 2 model of the Intergovernmental Panel on Climate Change. Country-specific CH4 emission factors for buffalo cows (630 kg body weight, BW) and other buffalo (313 kg BW) categories were estimated for the period 1990–2004. In 2004, the estimated enteric CH4 emission factor for the buffalo cows was 73 kg/head per year, whereas that for other buffalo categories it was 56 kg/head per year. Research in order to determine specific CH4 conversion rates at the predominant production system is suggested

    Effects of Chickpea in Substitution of Soybean Meal on Milk Production, Blood Profile and Reproductive Response of Primiparous Buffaloes in Early Lactation

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    This study aimed to evaluate the effects of the use of chickpea meal in substitution of soybean meal on plasma metabolites, reproductive response, milk yield and composition and milk coagulation traits of primiparous buffaloes in early lactation. Eighteen primiparous buffaloes were blocked by age, body weight and days in milk and equally allotted to two experimental groups from 10 to 100 days of lactation. The experimental diets consisted of the same forage integrated with two different isonitrogenous and isoenergetic concentrates containing either 210 g/kg of soybean meal or 371 g/kg chickpea. The use of chickpea meal had no negative effects on dry matter intake (p = 0.69), body condition score (p = 0.33) and milk yield (p = 0.15). Neither milk composition nor blood metabolites were influenced by dietary treatments (p > 0.05), but an increment of urea concentrations in milk (p 0.05) of the dietary treatment was highlighted on milk coagulation traits as well as buffalo reproductive responses. We concluded that soybean meal can be replaced by chickpea meal in the diet for primiparous dairy buffaloes in the early lactation period without impairing their productive and reproductive performance

    Effects of different fertilizers on quantity and quality of silage corn

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    Different fertilizers, ammonia sulfate and urea (MIN), Fertil 12.5 (ORG) and Azoslow (ORG-MIN) were compared in a silage corn crop. Total biomass yield was above 55.0 t ha-1 for all fertilizers. Azoslow showed the highest dry matter content (40.8%). No differences among the fertilizers were found in protein content (4.9% on average) at waxy ripening, with the control showing the lowest value (3.9%). There were also no differences in silage quality among the fertilizers. The N budget was estimated in order to quantify the residual nitrogen amounts at harvest and the efficiency of fertilizers

    Graduates’ employment and employability after the “Bologna Process” reform. Evidence from the Italian experience and methodological issues

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    In a phase of depression and systemic crisis investments are essential assets in organizing the recovery, and the more so when innovation is relevant. This is why universities, companies, households and graduates implement strategies for overcoming the present crisis, leading to structural changes and competition both at the local and international level. In this framework, tracer studies on graduates transition to the labour markets provides fundamental insights and information not only to the organizations responsible for their training, but also to the economic system as a whole. Moreover, any such study is all the more useful when it can draw upon reliable and up-to-date information. This paper emphasizes three main points. First we present the results achieved by the AL model in tracing the transition path of graduates from the time they enrolled at the university until a few years after earning the degree. The survey is carried out every year by the AL and makes it possible to analyze the most recent labour market trends through the scrutiny of the career opportunities available for the graduates after 1, 3 and 5 years on from graduation. More specifically, we will present the results of the 2008 survey. This survey involved also all first and second level graduates from the 2007 vintage. Second, we examine the revision in our survey method, adopted in order to face the need to monitor a much higher number of post-reform graduates (more than 140 thousand overall) and the call of the Ministry and the universities to keep the information as much detailed as possible in assessing the employment outcomes for each single degree course, without losing feasibility in terms of costs and data collection time. In fact, we resorted to a mixed method: the computer assisted web interviewing (CAWI) and the computer assisted telephone interviewing (CATI). This is why it became necessary to measure and assess the effect of this approach on the answers given by interviewed graduates. In third place, we outline the results of some preliminary experiments carried on in order to allow for specific and recurrent comparisons between the results achieved with the AL model and other similar models dealing with the employment conditions of Italian graduates.Graduates’ employment; Graduates’ employability; Bologna Process; University reform; University governance; Assessment of the higher education system; CAWI and CATI survey techniques; Propensity score matching; Data quality control; Counter factual analysis; Labour supply, Human capital.
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