A 12b 250 MS/s Pipelined ADC With Virtual Ground Reference Buffers

The virtual ground reference buffer (VGRB) technique is introduced as a means to improve the performance of switched-capacitor circuits. The technique enhances the performance by improving the feedback factor of the op-amp without affecting the signal gain. The bootstrapping action of the level-shifting buffers relaxes key op-amp performance requirements including unity-gain bandwidth, noise, open-loop gain and offset compared with conventional circuits. This reduces the design complexity and the power consumption of op-amp based circuits. Based on this technique, a 12 b pipelined ADC is implemented in 65 nm CMOS that achieves 67.0 dB SNDR at 250 MS/s and consumes 49.7 mW of power from a 1.2 V power supply

Energy requirement for maintenance of growing and adult male lesser mouse deer (Tragulus javanicus) in captivity.

A study was conducted to determine the energy requirement for maintenance of eight lesser mouse deer, consisting of four growing males (6–8 months of age) with average body weight of 1.4 ± 0.2 kg and four adult males (>2 years of age) with average body weight of 1.6 ± 0.2 kg. The animals were from the colony reared at the Department of Animal Science, Universiti Putra Malaysia. The experiment was based on a 2 × 4 factorial arrangement in Latin-Square design. The animals were kept in single pens and fed with different levels of feed (70%, 80%, 90% and 100% of ad libitum intake). The feed was made up of 95% pellet and 5% ‘kangkong’ (Ipomoea aquatica) leaves. The energy requirement for maintenance was determined by using the regression equations between metabolisable energy intake and energy retention or body weight change. Energy retention was calculated as the difference between metabolisable energy intake and heat production. The results showed that the metabolisable energy requirements for maintenance when calculated based on energy retention were 420.1 and 422.9 kJ kg−0.75 d−1 for growing and adult mouse deer, respectively, and when calculated based on weight change the values were 435.1 and 436.9 kJ kg−0.75 d−1, respectively. The efficiency of utilization of metabolisable energy for maintenance (km) for growing mouse deer was 0.58 and that for adult mouse deer was 0.54

Effect of varying dietary zinc levels and environmental temperature on the growth performance, feathering score and feather mineral concentration in commercial broilers

This study aimed to investigate the effects of dietary zinc (Zn), environmental temperatures and Zn× temperature interaction on growth, feathering score and mineral composition of broilers. A total of 256 d-old Avian male broiler chicks were randomly allocated to a 4×2 factorial arrangement with four corn-soybean meal basal diets (containing 44 mg Zn/kg) supplemented with 0, 40, 60 mg/kg Zn (Diets 1, 2 and 3, respectively; 0.8% Ca for these three diets) and non-Zn supplementation, 1.6% Ca (Diet 4)and two temperature conditions (low: 26, 24, 22°C vs. high: 30, 28, 26°C). All birds were given feathering coverage scores for back, breast, wing, under-wing and tail. The wing and tail were further evaluated for the occurrence and severity of defect feathers. Feathers were then pooled for mineral composition analysis. The results showed that in high temp erature conditions, broilers fed Zn-unsupplemented, 0.8% Ca ration (Diet 1) had significantly(p<0.05) lower ADFI and ADG (wk 1-6) than birds under low temperature conditions. However, when the birds were fed 40 and 60 mg/kg Zn supplementation (Diets 2 and 3), the ADFI and ADG in both temperature conditions were not significantly different. In low temperature conditions, the ADFI, ADG (p<0.05), all feather coverage (p<0.01) and tail defect scores (p<0.001) of birds fed Diet 4 (excess Ca) were significantly poorer than those fed Diet 1. More Ca (p<0.05) was retained in the feathers of broilers fed Diet 4 under high temperature conditions. Broilers fed the Zn-unsupplemented ration (D iet 1) had significantly higher feather phosphorus (p<0. 01) and potassium (p<0.05) concentrations than those fed the 60 mg/kg Zn-supplemented ration (Diet 3). A reduction of feather phosphorus (p<0.01) and potassium (p<0.05) and higher manganese (p<0.05) concentrations were observed in Diet 4 broilers as compared to those fed Diet 1.Under high temperature conditions, broilers had lower iron (p<0.05) and higher manganese (p<0.05) concentrations in feathers. Broilers kept in high temperature conditions had a higher Zn requirement and 40 mg/kg Zn supplementation was sufficient for the birds to achieve optimum growth. Suppl emental Zn ameliorated the adverse effect of high temperature on growth and occurrence of tail feather defects. Excess Ca disrupted Zn metabolism to exert a detrimental effect on growth performance and normal feathering and this was elucidated in the birds kept in low temperature conditions

Label-free shotgun proteomics and metabolite analysis reveal a significant metabolic shift during citrus fruit development.

Label-free LC-MS/MS-based shot-gun proteomics was used to quantify the differential protein synthesis and metabolite profiling in order to assess metabolic changes during the development of citrus fruits. Our results suggested the occurrence of a metabolic change during citrus fruit maturation, where the organic acid and amino acid accumulation seen during the early stages of development shifted into sugar synthesis during the later stage of citrus fruit development. The expression of invertases remained unchanged, while an invertase inhibitor was up-regulated towards maturation. The increased expression of sucrose-phosphate synthase and sucrose-6-phosphate phosphatase and the rapid sugar accumulation suggest that sucrose is also being synthesized in citrus juice sac cells during the later stage of fruit development

Effects of condensed tannins from Leucaena on methane reduction, rumen fermentation and populations of methaogens and protozoa in vitro

Different levels of purified condensed tannins (CT) extracted from Leucaena leucocephala hybrid-Rendang (LLR) were investigated for their effects on CH4 production, rumen fermentation parameters such as pH, dry matter (DM) degradability, N disappearance and volatile fatty acid (VFA) concentrations, as well as on populations of rumen methanogenic archaea and protozoa in vitro. Purified CT concentrations of 0 (control), 10, 15, 20, 25 and 30 mg, and 500 mg of oven dried guinea grass (Panicum maximum) with 40 ml of buffered rumen fluid were incubated for 24 h using an in vitro gas production procedure. Total gas (ml/g DM) decreased at a decreasing rate (linear P < 0.01; quadratic P < 0.05) with increased levels of CT inclusion. CH4 production (ml/g DM) decreased at a decreasing rate (linear P < 0.01; quadratic P < 0.01) with increasing levels of CT. Total VFA concentration (mmol/L) decreased at a decreasing rate (linear P < 0.01; quadratic P < 0.01) with increasing CT inclusions. In vitro DM degradation and N disappearance declined linearly (P < 0.01) with increasing levels of CT. Estimates of rumen methanogenic archaea and protozoa populations using microbiological methods and real-time PCR assay showed linear reductions in total methanogens (P < 0.01) and total protozoa (P < 0.01) with increasing levels of CT. Methanogens in the order Methanobacteriales also declined, but with quadratic and cubic aspects. Results suggest that CT from LLR at a relatively low level of 15 mg of CT/500 mg DM reduce CH4 production by 47%, with only 7% reduction in degradation of feed DM. However, higher CT inclusions, while further reducing CH4 emissions, have substantive negative effects on DM digestibility

Optimization of multi-enzyme production by fungi isolated from palm kernel expeller using response surface methodology

Response surface methodology (RSM) was used to optimize the co-production of a mixture of crude cellulosic and hemicellulosic enzymes (endoglucanase, xylanase, and mannanase) by Aspergillus terreus K1 in solid-state fermentation (SSF) using palm kernel expeller (PKE) as the sole carbon source. These enzymes have gained renewed interest due to their efficacy to improve the digestibility of PKE for use in diets of mono-gastric animals (poultry, pigs, and fish). The results showed that temperature, moisture, inoculum concentration, and initial pH had significant (P< 0.05) effects on the enzymes production. Using PKE as a solid substrate, maximum endoglucanase, mannanase, and xylanase (17.37, 41.24, and 265.57 U/g DM, respectively) were obtained at 30.5 °C, 62.7% moisture, 6% inoculum, and pH 5.8. The enzyme activities recorded were close to the predicted values (19.97, 44.12, and 262.01 U/g DM, respectively)