A phenomenological model for predicting the early development of the flame kernel in spark-ignition engines

This work presents a simple and effective phenomenological model for the prediction of the early growth of the flame kernel in SI engines, including its initiation as a result of the electrical breakdown of the fuel/air mixture between the spark plug electrodes. The present model aims to provide an improved description of the ignition-affected early phases of flame kernel development compared to the majority of models currently available in literature. In particular, these models focus on electrical energy supply and turbulence, whereas the stretch-induced kernel growth slowdown is quantified with linear models that are inconsistent with the small kernel radius. For the flame kernel initiation, this model replaces the current methods that rely on 1D heat diffusion within a plasma column with a more consistent analysis of post-breakdown conditions. Concerning the kernel growth, the present model couples the mass and energy conservation equations of a spherical kernel with the species and temperature profiles outside of it. This combination leads to a non-linear description of the flame stretch, according to which the kernel development is controlled by the Lewis-number-dependent balance between the heat gained via combustion and the heat lost via thermal diffusion. As a result, the kernel temperature differs from the adiabatic flame temperature, causing the laminar flame speed to change from its adiabatic value and ultimately affecting the overall kernel development. Kernel growth predictions are conducted for laminar flames and compared to literature data, showing a satisfactory agreement and highlighting the ability to describe the stretch-induced kernel slowdown, up to its possible extinction. A good agreement with literature data is also obtained for kernel expansions under moderately turbulent conditions, typical of internal combustion engines. The simple formulation of the present model enables swift integration into phenomenological combustion models for spark-ignition engines, while simultaneously offering useful insight into the early kernel development even for CFD-based approaches

Ranking and clustering of nodes in networks with smart teleportation

Random teleportation is a necessary evil for ranking and clustering directed networks based on random walks. Teleportation enables ergodic solutions, but the solutions must necessarily depend on the exact implementation and parametrization of the teleportation. For example, in the commonly used PageRank algorithm, the teleportation rate must trade off a heavily biased solution with a uniform solution. Here we show that teleportation to links rather than nodes enables a much smoother trade-off and effectively more robust results. We also show that, by not recording the teleportation steps of the random walker, we can further reduce the effect of teleportation with dramatic effects on clustering.Comment: 10 pages, 7 figure

Activation and inhibition of bimanual movements in school-aged children

The development of motor activation and inhibition was compared in 6-to-12 year-olds. Children had to initiate or stop the externally paced movements of one hand, while maintaining that of the other hand. The time needed to perform the switching task (RT) and the spatio-temporal variables show different agerelated evolutions depending on the coordination pattern (inor anti-phase) and the type of transition (activation, selective inhibition, non selective inhibition) required. In the anti-phase mode, activation perturbs the younger subjects' responses while temporal and spatial stabilities transiently decrease around 9 years when activating in the in-phase mode. Aged-related changes differed between inhibition and activation in the antiphase mode, suggesting either the involvement of distinct neural networks or the existence of a single network that is reorganized. In contrast, stopping or adding one hand in the in-phase mode shows similar aged-related improvement. We suggest that selectively stopping or activating one arm during symmetrical coordination rely on the two faces of a common processing in which activation could be the release of inhibitio

Comparing profitability of Burlina and Holstein Friesian cattle breeds

Aim of this study was to compare profitability of Burlina and Holstein Friesian cows in northern Italy. Cow's profitability was calculated for each breed, with consideration of economic incentive programs and alternative milk pricing scenarios. The difference in annual profitability between Burlina and Holstein Friesian ranged from −€719 to −€274 per cow per year. In a low-input management level with a cow's incentive payment and a specific cheese market strategy the low milk yield of Burlina can be compensate respect to Holstein Friesian

Updated distribution and characterization of crayfish plague and microsporidiosis affecting Austropotamobius pallipes complex in Trentino (Northeast Italy)

One of the causes of the decline in distribution and abundance of the endangered white-clawed crayfish Austropotamobius pallipes complex throughout Europe is the widespread invasion of alien crayfish and the associated spread of infectious diseases, primarily crayfish plague caused by Aphanomyces astaci. Although this disease usually causes mass mortality in A. pallipes, some wild populations appear tolerant towards A. astaci. Another relevant disease is microsporidiosis (porcelain disease), caused by the parasites Astathelohania contejeani and/or Nosema austropotamobii. In 2021-2024, we conducted a monitoring survey, aimed at mapping the distribution of A. astaci, A. contejeani and N. austropotamobii in wild populations of A. pallipes in Trentino (Northeast Italy). We applied non-invasive sampling methods to collect cuticular swabs from 31 of the 46 known populations, investigate the presence of A. astaci and if possible, identify its genotype through molecular analyses. Aphanomyces astaci was detected in 8 populations, and the presence of a low pathogenic genotype (genotype A) was confirmed in one of them. Thirty-three specimens from 10 populations showed macroscopic signs of porcelain disease, abdominal muscle tissues were collected and subjected to molecular evaluation. The presence of A. contejeani was identified in 23 individuals from 9 populations and N. austropotamobii was detected in 3 individuals, from 3 populations. 8 specimens collected from 6 populations were co-infected by the two microsporidians. This study was partly supported by the EU LIFE Programme: LIFE-CLAW, Crayfish Lineages Conservation in North-western Apennine (LIFE18 NAT/IT/000806), and by the SAGA and SAGA2 collaborative projects between FEM and IZSVe

Electrical neuroimaging of music processing reveals mid-latency changes with level of musical expertise

This original research focused on the effect of training intensity on cerebral and behavioral processing of complex music using high-density event-related potential (ERP) approaches. Recently we have been able to show progressive changes with training in grey and white matter and higher order brain functioning using (f)MRI ((functional) Magnetic Resonance Imaging), as well as changes in musical and general cognitive functioning. The current study investigated the same population of non-musicians, amateur pianists and expert pianists using spatio-temporal ERP analysis, by means of microstate analysis, and ERP source imaging. The stimuli consisted of complex musical compositions containing three levels of transgression of musical syntax at closure that participants appraised. ERP waveforms, microstates and underlying brain sources revealed gradual differences according to expertise in a 300-500 ms window after the onset of the terminal chords of the pieces. Within this time-window, processing seemed to concern context-based memory updating, indicated by a P3b-like component or microstate for which underlying sources were localized in right middle temporal gyrus, anterior cingulate and right parahippocampal areas. Given that the 3 expertise groups were carefully matched for demographic factors, these results provide evidence of the progressive impact of training on brain and behavior

Relationships between milk coagulation property traits analyzed with different methodologies.

Milk coagulation properties (MCP) analysis is performed using a wide range of methodologies in different countries and laboratories, using different instruments, coagulant activity in the milk, and type of coagulant. This makes it difficult to compare results and data from different research. The aims of this study were to propose a method for the transformation of values of rennet coagulation time (RCT) and curd firmness (a(30)) and to predict the noncoagulation (NC) probability of milk samples analyzed using different methodologies. Individual milk samples were collected during the morning milking in October 2010 from each of 165 Holstein-Friesian dairy cows in 2 freestall barns in Italy, and sent to 3 laboratories for MCP analysis. For each laboratory, MCP analysis was performed using a different methodology: A, with a computerized renneting meter instrument using 0.051 international milk clotting units (IMCU)/mL of coagulant activity; B, with a Lattodinamografo (Foss-Italia, Padova, Italy) using 0.051 IMCU/mL of coagulant activity; and C, with an Optigraph (Ysebaert, Frépillon, France) using 0.120 IMCU/mL of coagulant activity. The relationships between MCP traits were analyzed with correlation and regression analyses for each pair of methodologies. For each MCP trait, 2 regression models were applied: model 1 was a single regression model, where the dependent and independent variables were the same MCP trait determined by 2 different methodologies; in model 2, both a(30) and RCT were included as independent variables. The NC probabilities for laboratories with the highest number of NC samples were predicted based on the RCT and a(30) values measured in the laboratories with lower number of NC samples using logistic regression and receiver operating characteristic analysis. The percentages of NC samples were 4.2, 11.5, and 0.6% for A, B, and C, respectively. The transformation of MCP traits was more precise with model 1 for RCT (R(2): 0.77-0.82) than for a(30) (R(2): 0.28-0.63). The application of model 2 was needed when the C measurements were transformed into the other scales. The analyses of NC probabilities of milk samples showed that NC samples from one methodology were well distinguishable (with an accuracy of 0.972-0.996) based on the rennet coagulation time measured with the other methodology. A standard definition for MCP traits analysis is needed to enable reliable comparisons between MCP traits recorded in different laboratories and in different animal populations and breeds