Joint LDPC decoding and timing recovery using code constraint feedback

Timing recovery and channel decoding are traditionally performed independently. However, we show here that the information generated during the iterative decoding of low-density parity-check (LDPC) coded data can be fed back to the timing recovery circuit to enable accurate estimation of frequency and phase errors without the need for any pilot symbols. We describe a method capable of handling large offsets with complexity that grows linearly with offset size. Combining the LDPC constraint node observations with a properly calibrated phase locked loop allows successful tracking of a constant time delay, a frequency offset and a random phase walk.     

Screening of cider yeasts for sparkling cider production (Champenoise method)

A total of 350 colonies isolated from a cider cellar in Asturias (Spain) were identified by rDNA ITS-RFLP restriction analysis. Saccharomyces spp. strains were characterized by mitochondrial DNA (mtDNA) restriction analysis. Fifty-four different Saccharomyces spp. strains were identified and tested to ascertain their capacity to carry out secondary fermentation of sparkling ciders. The screening of yeasts to determine their principal enological characteristics (tolerance to ethanol, production of volatile acidity and hydrogen sulphide) was accomplished by means of rapid, non-expensive assays (plate agar). As a result, 13 (24%) of the 54 initial Saccharomyces spp. yeast strains were eliminated. The technological properties assessed were flocculation capacity, ethanol and sulphite tolerance, and production of major volatiles. Ten Saccharomyces cerevisiae strains were characterized as true flocculants; all of these strains were able to grow in ethanolic medium and in the presence of 200mg/l of sulphite. Applying cluster analysis to the production of amyl alcohols, isobutanol, propanol and 2-phenylethanol, the strains were classified in two natural groups. Two flocculent yeast strains referred to as 3' and 50', representative of the each statistical group, were selected together with two reference strains (Saccharomyces bayanus C6 and S. cerevisiae Levuline CHP) to elaborate four sparkling ciders by the Champenoise method. The analysis of variance (p<0.01) among ciders revealed that glycerol, acetaldehyde, ethyl acetate, methanol, propanol, i-butanol and 2-phenylethanol were significantly influenced by the secondary yeast strain. The results of sensory analysis indicated that all the sparkling ciders were scored as good. No significant differences among sparkling ciders were found for odour attributes and taste intensity.     

Effects of TiN and AlN Nanoparticles in Hot Deformation of Austenite in Steels

Recrystallisation kinetics of two low‐carbon steels, of which one with Ti and the other with Al as precipitate‐forming elements was studied by means of hot torsion tests. The mean size of TiN and AlN particles that precipitate during hot deformation was analysed by transmission electron microscopy (TEM). These results, along with the determination of the activation energy, the precipitated volume fraction and the diffusion coefficients of Ti, Al and N in austenite explain the ineffectiveness of these particles to inhibit the static recrystallisation.     

The effects of acquisition training schedule on extinction and reinstatement of cocaine self-administration in male rats.

Partial reinforcement is known to increase resistance to extinction (Rn) relative to training with continuous reinforcement. This phenomenon, referred to as the partial reinforcement extinction effect, is one of the most robust in learning and conditioning studies. Experiment 1 investigated manipulations known to affect the partial reinforcement extinction effect and determined their possible relevance for drug use patterns. Male rats received intravenous cocaine self-administration training under partial reinforcement (FR-10) training or continuous reinforcement (FR-1) conditions with either a low (0.25 mg/kg infusion) or a high cocaine dose (1.00 mg/kg infusion). Animals were placed on an extinction (recurrent nonreward) schedule for 10 days (1-hr sessions) prior to being tested for cue-induced reinstatement (single 2-hr session). Experiment 2 involved acquisition of cocaine self-administration under FR-1 conditions of short training (15 days) or extended training (30 days) with a low dose (0.25 mg/kg infusion) or a medium dose (0.50 mg/kg infusion) of cocaine reward prior to extinction or reinstatement. Experiment 1 showed that rats trained with FR-10-high dose outcomes exhibited greater Rn than the remaining groups. Additionally, FR-10-high dose and FR-10-low dose rats were more likely to return to active drug seeking during the reinstatement test. In Experiment 2, rats trained under FR-1-medium dose conditions were more persistent during extinction following short acquisition training than comparable rats experiencing extended acquisition training. The reinstatement test was conducted following extinction, in which it was observed that overtraining under FR-1-medium dose reward schedules resulted in a decrease in the tendency to return to active drug seeking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemical and sensory changes in fresh cider spirits during maturation in inert containers

BACKGROUND: Fresh cider spirits are alcoholic beverages mainly constituted by volatile compounds from apples that are formed during fermentation or generated during distillation. In this study the chemical and sensory changes that take place during the maturation of fresh cider spirits in inert containers made of stainless steel and glass were investigated. RESULTS: The type of container did not influence the maturation process for any of the studied compounds. Esterification, acetalisation and hydrolysis reactions occurred during the maturation of cider distillates over 24 months, giving rise to several changes in the original composition of this alcoholic beverage, but neither oxidation nor evaporation reactions were detected. A decrease in ethyl acetate, ethyl lactate, diethyl succinate and acetal was observed and an increase in fatty acid ethyl esters and 1,1,3‐triethoxypropane. Likewise, the sensory evaluation of the spirits was significantly influenced by the maturation time, with matured samples obtaining higher scores than fresh ones. CONCLUSION: The presence of reactive compounds in recently distilled products makes a period of around 12 months of maturation advisable to reach equilibrium and to improve the sensory assessment of cider distillates consumed in the fresh state. Copyright © 2010 Society of Chemical Industry