Morning versus afternoon cutting time of Berseem clover (Trifolium alexandrinum L.) affects feed intake, milk yield and composition in Girgentana goats

Twenty lactating Girgentana goats were used to evaluate the effect of morning v. afternoon cutting time of Berseem clover (Trifolium alexandrinum L.) on feed intake, milk yield and milk composition. Goats were randomly divided into two groups of ten animals, receiving 10 kg of fresh Berseem clover cut at 9.00 (AM group) or 16.00 (PM group), respectively; 500 g of concentrate was given individually to goats before offering forage. Feed intake increased (P<0·01) in the PM group (30·5 v. 25·3 g dry matter/kg body weight), associated with the different nutrient content of diets: lower crude protein but higher dry matter, neutral detergent fibre, water soluble carbohydrates (WSC) and total fatty acids in the PM-harvested forage. Milk production, protein and casein content were higher (P<0·05) in the PM group (1415 g/d, 3·25% and 2·42% v. 1277 g/d, 3·15% and 2·33%, respectively), whereas no differences between groups were detected for milk fat, lactose or urea content. Body weight slowly decreased from the start to the end of the experiment, without differences between groups. This study showed an important milk yield responses in Girgentana goats offered afternoon-cut compared with morning-cut Berseem clover, due to a marked increase in WSC in the afternoon-cut forage.     

Lamb meat quality as affected by a natural or artificial milk feeding regime

Fourteen Barbaresca lambs were divided into two groups of seven at 24h from birth and reared exclusively on natural milk (NR) or on artificial milk (AR). Lambs were slaughtered at 40 days of age. The NR group tended (P<0.10) to grow faster, thus resulting in a higher (P<0.10) carcass weight as compared to the AR group. AR meat was darker (P<0.05), leaner (P<0.001) and with a higher moisture (P<0.10) and ash (P<0.05) content than its counterpart. The proportion of polyunsaturated fatty acids was higher (P<0.01), while that of saturated lower (P<0.01) in meat from the AR group, resulting in a higher (P<0.01) polyunsaturated/saturated ratio. Linoleic acid content (P<0.001) and its n-6 series derivatives, except 9-12 trans C18:2 n-6 (P<0.001), increased more in the AR group meat than in the NR group. On the other hand, α-linolenic (P<0.001) and other n-3 series fatty acids were higher in meat from the NR group than in the AR group, leading to a lower (P<0.001) n-6/n-3 ratio. Furthermore, 9 cis 11 trans CLA was higher (P<0.001) in NR meat compared to AR meat. Finally, a milk-feeding regime exclusively based on artificial milk adversely affected the dietetic value of lamb meat compared to a natural rearing system, reducing the level of desirable fatty acids such as n-3 series and CLA.     

Meat quality and intramuscular fatty acid composition of Sanfratellano and Haflinger foals

The goal of the trial was to evaluate meat quality, with an emphasis on intramuscular fatty acid composition, of Sanfratellano foals, compared to that from Haflinger foals,both slaughtered at 18 months of age. Thirty foals, half of Sanfratellano breed and half of Haflinger breed, naturally weaned at 7-8 months, were divided into two homogeneous groups at 15 months of age and fed a finishing diet based on polyphite hay and concentrate. The finishing period lasted three months. Sanfratellano foals showed higher slaughter weight (P<0.05) as well carcass weight (P<0.05) compared to Haflinger foals. Meat physical and proximate analyses did not discriminate the two groups. Normal pH values (5.6-5.7) measured at 4-6 day post mortem were recorded in meat from both groups. Shear force values accounted (range 55-58N) for a favourable tenderness in both groups. The intramuscular fat level was low in both groups (<2.5%) supporting the healthy image of this meat. The proportion of linolenic acid was higher (P<0.01) in Haflinger meat than in Sanfratellano one, thus causing a higher (P<0.05) total n-3 fatty acid content. Overall meat from both groups showed a favourable repartition among saturated (36-37% total FAME's), monounsaturated (33% total FAME's) and polyunsaturated fatty acids (30-31% total FAME's).     

CMOS current‐steering DAC architectures based on the triple‐tail cell

In this paper two novel current‐steering digital‐to‐analog converter (DAC) architectures, exploiting the triple‐tail cell as switching element, are presented. The proposed solutions are theoretically analysed and design equations are carried out. The two architectures show better performance than the classical binary‐weighted solution and it is shown that they can profitably substitute the binary sub‐DAC section in a segmented topology. Theoretical results are compared with behavioural‐level simulations and confirm the effectiveness of the proposed architectures. Copyright © 2007 John Wiley & Sons, Ltd.     

Effects of nonlinear feedback in the frequency domain

A simple methodology to evaluate harmonic distortion in the frequency domain for circuits and systems made up of a nonlinear high-gain path with a nonlinear feedback network is presented. The approach provides compact closed-form expressions which constitute a direct extension of the classic ones valid at dc. The result improve our understanding of nonlinear frequency behavior in general feedback circuits and can even be used in manual design. The accuracy of the equations obtained was evaluated by comparison with computer simulations and measurements on an example circuit. Simulated and experimental data highly agree with the theoretical model.     

The Universal Circuit Simulator: A Mixed-Signal Approach to n-Port Network and Impedance Synthesis

A mixed-signal universal architecture able to emulate the behavior of an n-port analog circuit is presented. It exploits second-generation current conveyors as analog input/output blocks and a field programmable gate array circuit as digital processing element. A prototype is also discussed for the specific case of a two-port network synthesis and experimental results in agreement with expected ones are provided.     

0.6-V CMOS cascode OTA with complementary gate-driven gain-boosting and forward body bias

An innovative low-voltage low-power complementary metal-oxide-semiconductor (CMOS) gain boosting approach is presented. It exploits complementary gate-driven gain boosting and adopts forward body bias, resulting in the minimum possible supply requirement of one threshold plus two saturation voltages, without requiring any additional current branch. The solution is also exploited in a rail-to-rail high-performance single-stage cascode operational transconductance amplifier (OTA). Simulations using a 40-nm process with thresholds around 0.45 V show that 0.6 V and 50 μA are adequate to supply the designed OTA, which exhibits a 60-dB direct current (DC) gain, a 45-MHz unity-gain frequency, and an 18-V/μs slew rate, under a 1-pF load.     

Analysis of the noise characteristics of current-feedback operational amplifier

The noise performance of Current-Feedback Operational Amplifier (CFOA) is investigated in this paper and a general noise model useful for both simulation and hand calculation is proposed. Comparison with the noise characteristics of conventional op-amps is also carried out showing comparable noise voltage and worst noise current for the CFOA. Some peculiar CFOA features, having no equivalence in conventional op-amps, are also highlighted. Finally, SPICE simulations based on a standard bipolar technology are found to be in a very good agreement with the theoretical results.