4,395 research outputs found
On the variation of the fractional mean curvature under the effect of C1,α perturbations
In this brief note we study how the fractional mean curvature of order s 08 (0, 1) varies with respect to C1,\u3b1 diffeomorphisms. We prove that, if \u3b1>s, then the variation under a C1,\u3b1 diffeomorphism \u3c8 of the s-mean curvature of a set E is controlled by the C0,\u3b1 norm of the Jacobian of \u3c8. When \u3b1 = 1 we discuss the stability of these estimates as s \u2192 1- and comment on the consistency of our result with the classical framework
Welfare assessment: correlations and integration between a Qualitative Behavioural Assessment and a clinical/health protocol applied in veal calves farms
This study is aimed at finding correlations and possible integration among Qualitative Behavioural Assessment (QBA) and a specific protocol of clinical/health evaluation. Both welfare assessment methods were based on direct animal observation and were applied in 24 Italian veal calves farms at 3 weeks (wks) of rearing. Principal component analysis (PCA) summarized 20 QBA descriptors on two main components (PC1 and PC2) with eigenvalues above 4 and explaining 29.6 and 20.3% of the variation respectively. PCA on residuals obtained after correcting for housing condition yielded highly similar results, indicating that the rearing environment of the calves was not an important determinant of the observer reliability of QBA. A relationship was found between QBA PC2 and the presence of signs of cross-sucking recorded during the clinical visit (presence PC2=1.11 vs. absence PC2=-1.55,
Effect of Finnsheep crossbreeding on Lamon sheep performance: post-mortem traits
This experiment was conducted in order to study the effects of crossbreeding of the local breed Lamon (L) with Finnsheep (F),on the post-mortem performance of F, lambs (F x L). Nine L and 8 F x L ram-lambs were fattened with a diet (11.6 MJ M.E./kg d.m.) based on maize silage, dried sugar beet pulp and soybean meal, and slaughtered at 40.5 ± 5.9 kg live weight at the age of 22 weeks. Genotype did not affect dressing percentage on empty body weight (E.B.W.) but the crossbred lambs showed a lower incidence of the pelt (18,4 vs 20.2 % on E.B.W.;
Optical coherence tomography and optical coherence tomography angiography in uveitis : a review
Optical coherence tomography (OCT) has dramatically changed the understanding and management of uveitis and other ocular conditions. Currently, OCT angiography (OCTA) combines structural information with the visualization of blood flow within the imaged area. The aim of this review is to present the basic principles of OCT and OCTA interpretation and to investigate the role of these imaging techniques in the diagnosis and management of uveitis. Common complications of intraocular inflammation such as macular oedema and inflammatory choroidal neovascularization are often diagnosed and followed with OCT/OCTA scans. However, uveitis specialists can obtain much more information from tomographic scans. This review provides a comprehensive description of typical OCT/OCTA findings characterizing different ocular structures in uveitis, proceeding from the cornea to the choroid. A careful interpretation of OCT/OCTA images can help in the differential diagnosis, the prediction of clinical outcomes, and the follow-up of patients with uveitis
Mixture composition influence on schlieren images for simulated premixed -air flame
Schlieren techniques are widely utilized for flame characterization, and ongoing research at Politecnico di Milano focuses on employing tomographic Background Oriented Schlieren (BOS) technique to measure temperature distribution in an axis-symmetric H2-air premixed flame. The initial step in this process involves tomographic reconstruction of the refractive index distribution from the ray deflection measured from the BOS images. However, due to the unknown exact composition of the mixture, an assumption of constant composition (i.e., uniform Gladstone-Dale constant) must be made, which can significantly affect temperature accuracy.
The primary objective of this study is to analyze the dependency of refractive index and deflection on composition and how these parameters vary with changing equivalence ratios. This analysis is conducted through a 1-D planar simulation of an H2-air laminar premixed flame. Additionally, the study aims to assess whether similar outcomes can be achieved with an axis-symmetric refractive index field simulating a Bunsen-type burner flame.
The flame simulation employs the CANTERA Python suite with the FreeSolver tool and a kinetic mechanism model for H2 combustion. Refractive index computation in both 1D and axis-symmetric cases considers the real mixture composition, and three different scenarios assuming Gladstone-Dale constants for fresh mixture, exhaust gases, and air, applied uniformly.
For deflection estimation, a ray tracing algorithm is utilized, involving integration of a simplified form of the ray equation. Analysis of the 1D-case reveals that assuming a constant fresh mixture composition yields the most accurate results, with similar trends observed in the axis-symmetric case. Differences in results are lower for lean mixtures and increase for rich mixtures.
These findings deepen the understanding of composition's impact on deflections in Schlieren techniques and will facilitate accurate temperature estimation of the H2-air premixed flame through tomographic BOS
Searching for the Profitability of Energy Crops: An Agroecological–Economic Land Use Suitability (AE-landUSE) Model
The current geopolitical and energy market instability calls for speeding up the EU clean energy transition to increase energy security in all the European regions and make Europe the first climate-neutral continent by 2050. Among renewable energies, modern bioenergy is a promising near-zero-emission fuel for increasing energy security in the heating, electricity and transport sectors while promoting growth and job creation, especially in rural areas. In such a context, energy crops will continue to play a key role. Since agricultural planning is a complex issue, especially when energy crops could compete with food ones, we propose an agroecological–economic land use suitability model (AE-landUSE model) to promote the sustainable use of land resources. The AE-landUSE model was developed by integrating cost–benefit analysis (CBA) and land use suitability analysis (LSA) within geographic information systems (GISs). Tested in the Basilicata region (Southern Italy), comparing two different energy crops (rapeseed and cardoon), the results show the model’s utility in identifying suitable areas for energy crops where the investments will be cost-effective. The proposed model will help decision-makers in energy-agricultural planning to increase energy security sustainably
Comparison of wide field optical coherence tomography angiography with extended field imaging and fluorescein angiography in retinal vascular disorders
Purpose To compare swept source OCTA device, with and without the extended field imaging (EFI) technique, to standard fluorescein angiography (FA) in the clinical practice. Methods Consecutive patients with vascular disorder patients underwent FA with 55-degree lens (Spectralis Heidelberg Engineering, Heidelberg, Germany) and OCTA with the prototype PlexElite (Carl Zeiss Meditec, Dublin, CA) using a 12 mm x 12 mm volume scan pattern centered on the fovea and a prototype of + 20.00-diopter designed specifically by Zeiss. The imaging methods were compared for visible field of view, extension of non-perfused areas, presence and number of neovessels, vessel density (VD) and fractal dimension (FD). Results Forty-three eyes of 27 patients were included. The mean extension ratio of EFI SS-OCTA compared to SS-OCTA without EFI and FA were 1.97 \ub1 0.02 and 0.85 \ub1 0.01. The mean extension of non-perfused areas with EFI SS-OCTA (34.22 \ub1 33.4 mm 2 ) was significantly higher than SS-OCTA without EFI (20.46 \ub1 18.70 mm 2 ), and with FA (27.55 \ub1 4.4 mm 2 ). The mean VD and FD of EFI SS-OCTA were significantly different compared to SS-OCT without EFI. Conclusions EFI SS-OCTA captured larger areas than SS-OCTA without EFI and FA. OCTA in a single shot is able to obtain more information of the retina without the use of montage techniques. Despite the determination of retinal ischemia seems to be easier and more accurate using EFI SS-OCTA, FA offers more details of the perfusion status of the retina
SAM multipliers and subsystems: Structural analysis of the Basilicata’s agri-food sector
Local agri-food products are conceived as a form of cultural capital, representing potentially fruitful resources for rural development. Italy and its regions offer a rich and diverse agricultural and food heritage that has led to the creation of numerous quality agri-food systems. Despite their ability to absorb disturbances and maintain their functions, it is important to develop economic models targeted to analyse the relationships among the components of food systems, in order to identify their strengths and weaknesses and drive the implementation of sectoral policies. In view of the new Rural Development Programme (2014-2020), the aim of this work is to analyse the structure of the Basilicata’s agri-food system using a multi-sector model based on a two-region SAM, specifically developed for Basilicata, an Italian region charac-terised by a highly specialised agri-food sector. Results show that the availability of a highly disaggregate multi-sector model of the regional economy may be a valuable supporting tool to design regional policies for innovation and for the development of rural areas, laying the foundation for further analysis
Growth performance, cleanliness and lameness of finishing Charolais bulls housed in littered pens of different design
The fattening of beef cattle in Italy is mainly carried out under intensive rearing conditions. The main features of the Italian beef farms are the high stocking rate and the loose housing of the animals in multiple pens indoors. The pen with fully slatted floor is the most frequent housing solution because it does not require any bedding material and it has a lower labour cost to remove slurry
- …