Could predicting fatty acid profile by mid-infrared reflectance spectroscopy be used as a method to increase the value added by milk production chains?

The aims of this work were (1) to develop prediction equations from mid-infrared spectroscopy (MIRS) to establish a detailed fatty acid (FA) composition of milk; (2) to propose a milk FA index, utilizing MIRS-developed equations, in which the precision of the FA-prediction equations is taken into account to increase the value of milk; and (3) to show application examples. A total of 651 bulk cow milk samples were collected from 245 commercial farms in northwest Italy. The results of the 651 gas chromatography analyses were used to establish (421 samples) and to validate (230 samples) the outcomes of the FA composition prediction that had been obtained by MIRS. A class-based approach, in which the obtained MIRS equations were used, was proposed to define a milk classification. The method provides a numerical index [milk FA index (MFAI)] that allows a premium price to be quantified to increase the value of a favorable FA profile of milk. Ten FA were selected to calculate MFAI, according to their relevance for human health and potential cheese sensory properties, and animal welfare and environmental sustainability were also considered. These factors were selected as dimensions of MFAI. A statistical analysis and expert judgment aggregation were performed on the selected FA by weighting the FA and normalizing the dimensions to reduce redundancy. A class approach was applied, using the precision of the MIRS equations to establish the classes. The median FA concentration of the data set was set as a reference value of class 0. The width, number, and limits of classes above and below the median were calculated using the 95% confidence level of the standard error of prediction, corrected with the bias of each FA. A progressive number and a positive or negative sign were assigned to each FA class above or below the median according to their role in the above mentioned dimensions. The sum of the numbers of each class, associated with its sign for each FA, was used to generate MFAI. The MFAI was applied to dairy farms characterized by different feeding strategies, all of which deliver milk to a commercial dairy plant. The MFAI values ranged from 0.7 to 4.2, and large variations, which depended on the cows' diet and forage quality, were observed for each feeding system. The proposed method has been found to be flexible and adaptable to several contexts on both intensive and extensive dairy farms.     

Linear transport theory for particles moving on a spherical surface

The paper deals with a linear transport model for particles moving on a spherical surface in the presence of absorption and scattering events. Starting from the analytical expression for the particle density in the case of a pure absorbing sphere, an integral equation is derived for situations in which isotropic scattering is present. The equation has been solved numerically in order to obtain the Green function of the problem. Analytical and numerical results are compared with those obtained resorting to the Monte Carlo method.     

Effect of different feeding strategies in intensive dairy farming systems on milk fatty acid profiles,and implications on feeding costs in Italy

The aim of this work was to characterize the fatty acid (FA) profile of milk from intensive dairy farming systems in the Po Plain (Italy) to estimate the costs of the adopted feeding strategies and to simulate the effect of supplementary premiums on the basis of milk FA composition on milk income. Twenty dairy farms with 5 different feeding strategies were studied: 3 corn silage-based systems in which cows were supplemented with a great proportion (CCH), a medium proportion (CCM), or without commercial concentrate mix (CC0), and 2 systems in which part of corn silage was replaced with grass or legume silage (HF) or with fresh herbage (G), cut and fed indoors. Bulk milk was sampled and lactating cow performance, feeding strategies and forage characteristics were recorded through a survey, 3 times during a year. The milk FA supplementary premium was calculated considering C18:3n-3 and saturated FA (SFA) concentrations, and ratio of total cis C18:1 isomers to C16:0. The CCH, CCM, and CC0 systems bought most of their dairy cow feeds off farm, which allowed them to increase milk production to 35,000 L/yr per hectare. Their low dry matter and crude protein self-sufficiency led to higher feeding costs per liter of milk (from €0.158 to €0.184), and highest income over feed cost was achieved only for milk yield performance greater than 10,000 kg/cow per year. The use of homegrown forages in HF and G increased dry matter and crude protein self-sufficiency and reduced the feeding costs per liter of milk from 9 to 22%, compared with the other studied systems, making HF and G feeding economically competitive, even for a lower milk yield per cow. The studied systems highlighted a remarkable variation in FA profiles. The concentrations of C16:0 and SFA were the highest in CCH (31.53 and 67.84 g/100 g of FA) and G (31.23 and 68.45 g/100 g of FA), because of the larger proportion of commercial concentrate mix in the cow diet. The concentrations of C16:0 and SFA were the lowest in CCM (27.86 and 63.10 g/100 g of FA), because of low roughage-to-concentrate ratio in the cow diet, which is known to favor milk fat depression, affecting particularly these FA. The calculated supplementary premium was the highest in the CCM system, based on milk FA profiles from those herds. The HF diet was rich in forages and resulted in greater concentration of C18:3n-3 in milk (0.57 g/100 g of FA) than the other systems and thus led to an increase in milk FA supplementary premium. Milk from G and HF milk had the lowest ratio of Σn-6:Σn-3 FA compared with milk from the systems based on higher corn silage proportion in the cow diet (3.71, and 3.25, respectively, vs. 4.58 to 4.78), with the lower ratios being closer to recommendation for human nutrition.     

A Numerical Model to Explain Experimental Results of Effective Thermal Conductivity Measurements on Unsaturated Soils

Effective thermal conductivity measurements on unsaturated soils by means of the probe method (thermal conductivity probe, TCP) often present a nonlinear trend of \(\Delta T\) versus ln (\(\tau \)). Three different slopes are present in the plots, while a homogeneous material should present only one. Being soils composite structures made of different phases (solid earth, liquid water and air), a possible explanation is the presence of phenomena other than pure conduction, such as water evaporation and vapor migration through the soil structure. A numerical model based on finite differences has been developed to simulate these phenomena. The model takes into account several factors including heat conduction, heat storage due to thermal capacity, water evaporation and water diffusion through a porous medium. Results show that two of the three slopes can be successfully simulated by the model, confirming the interpretation of the phenomena. However, the third slope from the experimental data is lower than the model’s slope, likely indicating the presence of other phenomena not yet taken into account, such as capillarity.     

Fiber birefringence measurements with an external stress method and heterodyne polarization detection

Precise birefringence measurements on polarization maintaining fibers have been obtained with external pressure scanning along the fiber axis. Output detection has been performed through heterodyne interferometric polarimetry, which allows the use of a simplified technique (avoiding pressure modulation and fiber eigenaxis search). Beat-length evaluation is achieved directly through multiple counting of periodical variations of the two radio-frequency output signals provided by the polarimeter. A theoretical model for the behavior of the fiber output polarization on the Poincare' sphere, as a function of pressure scanning, has been developed and experimentally tested and the results are in good agreement with the theory.     

New analysis of microbending losses in single-mode fibres

A new and powerful analysis of microbending in generic single-mode fibres is outlined. The calculation avoids cumbersome evaluations of the coupling coefficients and allows the derivation of a simple and better approximated expression for the microbending losses. More severe upper and lower bounds to the possible losses are also provided.     

Near-field measurements in monomode fibres: determination of chromatic dispersion

A new dispersion measurement for monomode fibres is proposed. It is based on an elaboration of the near-field intensities at different wavelengths. The measurement is considerably simplified and the results are highly accurate.     

MRI appearances in amoebic granulomatous hepatitis: a case report

Amoebiasis is a common cause of liver disease usually presenting as single large or multiple smaller abscesses. Cases with granulomatous hepatitis have rarely been described. We report the case of a 7-year-old girl with amoebic granulomatous hepatitis in which multiple liver abscesses were demonstrated by MRI. A total of 14 abscesses were identified, ranging from 5 mm to 3 cm in diameter. The largest lesions appeared to T2-weighted images as heterogeneous, low-intensity areas surrounded by a double-layered wall, the inner layer of which was hyperintense and the outer layer hypointense. These signs, which have never been described in classic amoebic abscess, represent, we believe, a pattern of hepatic granulomatous amoebiasis lesions. We suggest that MRI should always be performed in cases of amoebic infection.     

Solution of wave equation in graded-index optical fibres by means of multiparabolic approximation

A new numerical method for the solution of the wave equation in fibres with any profile, consisting in approximating the profile with a suitable set of parabolas, is proposed. The method results are very powerful as regards the precision in propagation constants and group delays, and in computing speed, particularly for near optimum profiles.