Fatty acid profile of milk from goats fed diets with different levels of conserved and fresh forages

Aim of the study was to evaluate the effect of different proportions of hay and fresh grass in goats’ diet on milk fatty acid profile. Nine Camosciata goats were fed a fixed amount of concentrate (30% of total diet) and different percentages (40% vs 30%, 50% vs 20% and 60% vs 10%) of hay and fresh grass, respectively. Diminishing amounts of fresh grass percentages in the diet led to significant increases of lauric, myristic and palmitic acids (P ≤ 0.001) and to significant decreases of C18:1 t6‐11, rumenic and α‐linolenic acids (P ≤ 0.001) in milk, thus determining a worsening of the health value of milk fat.     

冷却剂丧失条件下钠冷快堆棒束传热的三维蒙特卡罗模拟方法

采用蒙特卡罗方法分析钠冷快堆在假想冷却剂丧失条件下燃料棒束的钠两相流传热问题。以分子运动理论的基本定律为基础，开发出替代宏观经验模型来分析反应堆棒束中的钠蒸发率和冷凝率的微观模型，且采用三维蒙特卡罗方法模拟分子的运动轨迹，分子间的碰撞率以及分子与棒束、分子与棒束组件盒壁的碰撞率。对包壳干涸区的再浸润现象用动力膜模型描述，并计算了通过液膜的液体速度分布和平均液膜速度，对于从冷凝液膜蒸发的钠分子则被重新记为蒙特卡罗计算的源项。用微观和宏观模型相结合的方法数字模拟了德国卡斯鲁尔研究中心的堆外钠沸腾实验。     

A PROLOG APPROACH TO IMAGE SEGMENTATION

Segmentation is a main problem in computer vision. It attempts to supply primitives for higher-level processes of interpretation. A multithreshold approach has already given acceptable results. This paper presents a PROLOG implementation of a multithreshold system. The system uses the technique of recursive partition of two-dimensional images in quadrants to form maximal blocks; the data structure generated by this partition algorithm is known as a quadtree. The algorithms implemented concern image representation, connected regions, identification, and contour detection. The improvement of algorithms in a logic language rather than in a procedural one appeared to be of particular interest. The main reasons for this are implementation facility and the natural use of logic programming in the field of knowledge-based systems. In fact, a knowledge-based approach seems a reasonable solution to problems of assisted image understanding processes.     

Characterization by Nuclear and Spectrophotometric Analysis of Near-Surface Modifications of Glass Implanted with Heavy Ions

A soda-lime-silica glass was irradiated by different heavy ion (N, Ne, Ar, and Kr) with energies chosen in order to obtain the same penetration depth. The near-surface sodium depletion layer, characterized by nuclear analysis and infrared reflectance spectrophotometry (IRRS), is deeper than the implanted-ion range and grows with increasing incident-ion mass at the same dose and current density. By using reflectance spectrophotometry in the solar range, the formation of a near-surface perturbed layer having a modified refractive index as compared to the bulk and a thickness comparable to the sodium depletion layer was confirmed.     

A SPECTRAL APPROACH TO THE STUDY OF PROPAGATION PHENOMENA IN CNNs

The propagation phenomena occurring in cellular neural networks (CNNs) described by a one-dimensional template are investigated using a spectral technique. The CNN is represented as a scalar Lur'e system to which a suitable extension of the describing function technique is applied for predicting the existence and characteristics of spatiotemporal periodic oscillations. It is shown that such a method yields results that are in good agreement with those observed by time simulation of the system.     

OPTIMAL ROBUST DESIGN OF NOVEL MATERIALS: PROBLEMS OF STABILITY AND VIBRATIONS

A numerical method for the optimal design of thin anisotropic laminates is presented, layer thicknesses and lamination angles being the design variables. An optimal solution is pursued with respect to frequency domain objectives, e.g. fundamental frequency and Euler critical load. A special feature of the method is the semi-analytical second order design sensitivity that is computed with the aid of a Rayleigh-Ritz analysis approach. A modified sequential quadratic programming scheme is then introduced, where standard quasi-Newton approximations are avoided by an exact calculation of the Hessian matrix. Furthermore, the robustness of the method with respect to scatter in material properties such as mass density and elastic moduli is assessed. A stochastic extension of the Rayleigh-Ritz approach is developed on this purpose that allows the location of those regions in the design space that are most sensitive to physical parameter randomness. This allows the use of a modified objective function that penalizes sensitive solution.     

PRELIMINARY EVALUATION OF THE APPLICATION OF THE FTIR SPECTROSCOPY TO CONTROL THE GEOGRAPHIC ORIGIN AND QUALITY OF VIRGIN OLIVE OILS

ABSTRACT

A rapid Fourier transform infrared (FTIR) attenuated total reflectance spectroscopic method was applied to determine qualitative parameters such as free fatty acid (FFA) content and the peroxide value (POV) in virgin olive oils. Calibration models were constructed using partial least squares regression on a large number of virgin olive oil samples. The best results (R² = 0.955, root mean square error in cross validation [RMSECV] = 0.15) to evaluate FFA content expressed in oleic acid % (w/w) were obtained considering a calibration range from 0.2 to 9.2% of FFA relative to 190 samples. For POV determination, the result obtained, built on 80 olive oil samples with a calibration range from 11.1 to 49.7 meq O₂/kg of oil, was not satisfactory (R² = 0.855, RMSECV = 3.96). We also investigated the capability of FTIR spectroscopy, in combination with multivariate analysis, to distinguish virgin olive oils based on geographic origin. The spectra of 84 monovarietal virgin olive oil samples from eight Italian regions were collected and elaborated by principal component analysis (PCA), considering the fingerprint region. The results were satisfactory and could successfully discriminate the majority of samples coming from the Emilia Romagna, Sardinian and Sicilian regions. Moreover, the explained variance from this PCA was higher than 96%.

PRACTICAL APPLICATIONS

The verification of the declared origin or the determination of the origin of an unidentified virgin olive oil is a challenging problem. In this work, we have studied the applicability of Fourier transform infrared coupled with multivariate statistical analysis to discriminate the geographic origin of virgin olive oil samples from different Italian regions.