An alternative formulation of classical electromagnetic duality

By introducing a doublet of electromagnetic four dimensional vector potentials, we set up a manifestly Lorentz covariant and SO(2) duality invariant classical field theory of electric and magnetic charges. In our formulation one does not need to introduce the concept of Dirac string.Comment: 14 pages, no figures, Latex, minor corrections, references and acknowledgements adde

Short communication: Mutual olfactory relationships in rabbits raised in individual cages

[EN] A set of three contiguous cages was utilised to test the possibility that rabbits establish sniffing relationships when housed in contiguous cages as occurs on farms. The single cages were separated by a tin divider slide in which very small holes were made. This system allows the smell to be sensed while a visual relationship was not possible. The experimental set was then located in an open air shed under a roof with no walls, in order to allow olfactory stimuli and to make it possible to perceive its direction and possibly its origin. This set-up avoided the odours saturating the environment so that the animals could sense each other's presence. Three 16 wk old does were housed in contiguous cages at the same time. The animals were video-recorded at one frame per minute for 8 consecutive days and a total of 11,500 frames per animal were recorded. The trial was replicated under the same conditions with three new does. Progressively decreasing sniffing behaviour (P<0.001) was observed. The behaviour of all the does in the lateral cages was similar and there were no significant differences. Frequent reciprocal sniffing was also observed, mainly in the first few days. The results indicate that a sniffing relationship is established among rabbits but this behaviour decreases rapidly. It is possible that after the initial interest shown, rabbits do not show any specific behavioural changes when sensing other animals.Negretti, P.; Bianconi, G.; Finzi, A. (2010). Short communication: Mutual olfactory relationships in rabbits raised in individual cages. World Rabbit Science. 18(1):33-36. doi:10.4995/wrs.2010.18.05333618

Visual image analysis to estimate morphological and weight measurements in rabbits

[EN] Visual Image Analysis (VIA) has been evaluated to estimate morphological traits and weights of live rabbits and carcasses to improve the body conformation of the new breed Leprino di Viterbo. The reliability of VIA was firstly tested on a sample of 30 does. Then, a total of 365 animal (130 additional does and 205 rabbits at slaughtering weight of kg 2.5) was utilised to calculate some surface traits and correlations between live and carcass weights that were later validated over a new sample of 112 rabbits (37 does and 75 fattened). VIA gave very good results to evaluate morphological and weight measurements. Maximum observed individual difference between data measured by metre and by VIA was only 3.6%. Since standard error (SE) of VIA was lower than SE of metre (0.06 and 0.33 respectively), VIA was considered more reliable than the instrumental measurement. A new parameter, Body Side Surface, was made available by the Image Analysis to estimate Live Weight and Carcass Weight efficiently. Correlations were high (P<0.01) both in does (R2=0.87 for live weight equation) and at slaughter time (R2=0.82 and 0.76 for live and carcass weight equations, respectively). It was concluded that VIA is a viable, quick and practical mean to measure and select for weight and morphological traits as head length, ear length, body length and body side surface.Negretti, P.; Bianconi, G.; Finzi, A. (2007). Visual image analysis to estimate morphological and weight measurements in rabbits. World Rabbit Science. 15(1):37-41. doi:10.4995/wrs.2007.606374115

SVILUPPO DI TECNOLOGIE INNOVATIVE PER LA CARATTERIZZAZIONE DEGLI EFFLUENTI DI ALLEVAMENTO AI FINI DELLA LORO VALORIZZAZIONE AGRONOMICA ED ENERGETICA

Currently there are two important issues related to the management of manure. The first concerns the agronomic use of effluent. Very often, during deployment in the field, the nutrient content is unknown or underestimated. The second concerns the treatment of anaerobic digestion - widely used to treat effluents - because in many cases the process does not proceed optimally because those who manage not have the necessary skills. At the time the laboratory analysis are the only way to get information. However this system is expensive, impractical in sampling and slow to deliver the results with respect to the requirements dictated by the timing of the distribution field and in the anaerobic digestion process. The need to have available analytical data at farm level when required and at a reasonable cost, has led to carry out specific research activities. A first set of technologies tested by many authors for the indirect analysis of the nutrient content in manure, regards physico-chemical and electrical measures. These are represented by the measurement of electrical conductivity (EC), which has a good correlation with the content of ammonia nitrogen and potassium; density that has good correlations with the content of dry matter and phosphorus and pH as a parameter of support for EC and density. The second technology examined is the near-infrared spectroscopy - NIR. Many authors have already successfully used to analyze manure and digestate with limited errors, to predict the content of total nitrogen, ammonia nitrogen, volatile fatty acids and dry matter. Then, we studied how to simplify complex technologies and then make transferable from the laboratory to the field, able to measure the amount of nutrients and volatile fatty acids contained in the livestock slurry and digestate. In this study we tried to identify the analytical methods and the best technological solutions to be transferred to prototype devices to be used in farm. At this stage, we tried to understand which factors could affect the measurement quality, functionality and cost of construction of the prototype. The development of prototypes has led to realize two devices, prototype EPD (to measure Electrical conductivity, pH and density) and the prototype NIR. The reliability of the prototypes to support the agronomic use of manure, can be refined considering the information relating to the management of livestock (housing, feeding and manure management). In the context of the energy recovery of manure, the information obtained from the prototypes, they may become more important if integrated within the system to support the management of anaerobic digestion plants, based on fuzzy logic. The experimental tests have confirmed a general ability of the measuring system to predict dry matter, nitrogen, phosphorus and the AGVs contained in slurries and digestates. There are still critical issues and it is therefore necessary to continue with further study of the measurement system. Ultimately, the use of indirect methods and tools to be used for in situ characterization of the effluents can lead to a significant improvement of the environmental and energy enhancement of the manure towards sustainable intensive agriculture

A Survey of Dairy Cattle Behavior in Different Barns in Northern Italy

Due to its increasing pressure on dairy cows, studies that investigate how to cope with heat stress are needed. The heat stress affects multiple aspects of cows' lives, among which their behavior and welfare. In this study, a survey was carried out in eight farms located in Northern Italy to monitor and evaluate the environmental aspects of the barns and the behavioral responses of dairy cows. For one year, three periods were monitored: thermoneutral (T_S), hot (H_S) and cold (C_S) seasons. Temperature and relative humidity were measured by environmental sensors, and lying vs. standing time, number of lying bouts and their average duration were collected by accelerometers. The temperature-humidity index (THI) was quantified inside and outside of the barn. Results show that at the increase of the THI, behavioral adaptations occurred in all the farms, especially with a reduction of lying time and an increase of respiration rate. Four of the eight farms need interventions for improving the cows' welfare. Here, environmental problems should be solved by introducing or improving the efficacy of the forced ventilation or by modifying the barn structure. Monitoring dairy barns with sensors and Precision Livestock Farming techniques can be helpful for future livestock farming to alert farmers on the need for their interventions to respond immediately to unwanted barn living conditions

Effect of short range order on electronic and magnetic properties of disordered Co based alloys

We here study electronic structure and magnetic properties of disordered CoPd and CoPt alloys using Augmented Space Recursion technique coupled with the tight-binding linearized muffin tin orbital (TB-LMTO) method. Effect of short range ordering present in disordered phase of alloys on electronic and magnetic properties has been discussed. We present results for magnetic moments, Curie temperatures and electronic band energies with varying degrees of short range order for different concentrations of Co and try to understand and compare the magnetic properties and ordering phenomena in these systems.Comment: 15 pages,17 postscript figures,uses own style file