A semi-Lagrangian scheme for the game pp-Laplacian via pp-averaging

We present and analyze an approximation scheme for the two-dimensional game $p$-Laplacian in the framework of viscosity solutions. The approximation is based on a semi-Lagrangian scheme which exploits the idea of $p$-averages. We study the properties of the scheme and prove that it converges, in particular cases, to the viscosity solution of the game $p$-Laplacian. We also present a numerical implementation of the scheme for different values of $p$; the numerical tests show that the scheme is accurate.Comment: 34 pages, 3 figures. To appear on Applied Numerical Mathematic

An existence result for the sandpile problem on flat tables with walls

We derive an existence result for solutions of a differential system which characterizes the equilibria of a particular model in granular matter theory, the so-called partially open table problem for growing sandpiles. Such result generalizes a recent theorem of Cannarsa and Cardaliaguet established for the totally open table problem. Here, due to the presence of walls at the boundary, the surface flow density at the equilibrium may result no more continuous nor bounded, and its explicit mathematical characterization is obtained by domain decomposition techniques. At the same time we show how these solutions can be numerically computed as stationary solutions of a dynamical two-layer model for growing sandpiles and we present the results of some simulations.Comment: 15 pages, 11 figure

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

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

Technical, economic, and environmental assessment of a collective integrated treatment system for energy recovery and nutrient removal from livestock manure

The aim of this 5-year study was to evaluate the technical, economic, and environmental performances of a collective-based integrated treatment system for bioenergy production and nutrients removal to improve the utilization efficiency and reduce the environmental impact of land applied livestock manure. The study involved 12 livestock production units located in an intensive livestock area designated as nitrate vulnerable zone with large N surplus. The treatment system consisted of an anaerobic digestion unit, a solid-liquid separation system, and a biological N removal process. Atmospheric emissions and nutrient losses in water and soil were examined for the environmental assessment, while estimated crop removal and nutrient utilization efficiencies were used for the agronomic assessment. The integrated treatment system achieved 49% removal efficiency for total solids (TS), 40% for total Kjeldahl nitrogen (TKN), and 41% for total phosphorous (TP). A surplus of 58kWh/t of treated manure was achieved considering the electricity produced by the biogas plant and consumed by the treatment plant and during transportation of raw and treated manure. A profit of 1.61 \ubf/t manure treated and an average reduction of global warming potential by 70% was also achieved. The acidification potential was reduced by almost 50%. The agronomic use of treated manure eliminated the TKN surplus and reduced the TP surplus by 94%. This collective integrated treatment system can be an environmentally and economically sustainable solution for farms to reduce N surplus in intensive livestock production areas

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 a biological additive on nitrogen losses from pig slurry during storage

Additives applied to animal manure slurries can affect the chemical composition and the biological processes of slurries during storage, with possible improvement of their management and reduction of environmental problems. Some new formulations are marketed claiming a nitrogen (N) removal effect due to denitrification, with the consequence of a reduced N content in the manure after storage. This study evaluated the effects of one of these commercial additives (BACTYcomplex) on slurry characteristics and N losses at a commercial piggery. The additive was applied to four different sectors of the piggery, each with an independent under-floor slurry pit; four other sectors served as controls without treatment. Pits were emptied every 4 wk, and the manure was analyzed for total and ammonia-N and total and volatile solids. Slurry samples from the last month of the on-farm assessment were removed and stored thermostatically in vessels external to the piggery. A subsample of slurry that was treated with the additive at the piggery was treated with an additional dose of additive at the beginning of long-term storage. The additive did not change the composition of the slurry during in-house storage (4 wk duration). During the 155 d of external thermostatic storage, the total solids content of treated slurry was reduced by 18% compared with control slurry, but the N content and composition of treated slurry was unaffected. The additive had a positive effect in accelerating the stabilization of the slurry but did not modify N losses

Geometry, kinematics and rates of deformation in a normal fault segment boundary, central Greece

The geometry, kinematics and rates of deformation within a fault segment boundary between the ends of two major active normal fault segments have been investigated through examination of a faulted 126 ka marine terrace. Slip‐vector azimuths defined by striations on the faults indicate N‐S extension on c. E‐W faults, sub‐parallel to those from earthquake focal mechanisms, together with significant and contemporaneous E‐W extension on c. N‐S faults. Summed rates of E‐W extension along a c. 550 m transect (0.17 mm/yr) are comparable with those for N‐S extension (0.20 mm/yr) along a c. 350 m transect. Our observations show that distributed non‐plane strain extension occurs in fault segment boundaries and this should be noted when studying fault‐tip fracture toughness and regional deformation rates

Effects of climatic conditions on the lying behavior of a group of primiparous dairy cows

Currently, lying behavior can be assessed using continuous observations from sensors (e.g., accelerometers). The analysis of digital data deriving from accelerometers is an effective tool for studying livestock behaviors. Despite the large interest in the lying behavior of dairy cows, no reference was found in literature regarding the prediction of lying behavior as a function of the interaction of environmental parameters. The present study aimed to evaluate the influence of climatic conditions (temperature-humidity index, solar radiation, air velocity and rainfalls) on the lying behavior of a group of primiparous dairy cows, using data from accelerometers, and develop a prediction model to identify and predict the lying behavior of dairy cows as a function of the effects of environmental conditions. Results from the. GLM Procedure (SAS) showed that the model was highly significant (p &lt; 0.001) and the r2 was 0.84. All of the effects in the model resulted in being highly significant (p &lt; 0.001). This model, if validated properly, could be a valid early warning system to identify any deviation from the expected behavior, and to assess the effectiveness of thermal stress mitigation strategies