A study on performances of intensification in the farming system of a shrimp farm at Cox's Bazar, Bangladesh

This study examines the harvest and mean production in relation to the stocking of P. monodon fry during the period between March 1992 and October 1994, at the farm owned by M/s Monugung Sea Food Ltd., Cox's Bazar. The analysis shows that production figures were initially up to expectation, but after harvesting 4 crops within 16 months, production sharply decreased. The unexpected high mortality of the growing stock was due to outbreak of an uncontrollabe disease (Vibriosis). Significantly higher variations in production, survival and growth were also noted among the different treatments.

Chemical changes in skin mucin as an index of early stages of spoilage in fish

Results of a preliminary investigation on the overall chemical nature of fish skin mucin in lung fish, Clarias batrachus, with special reference to water soluble low molecular weight compounds, are presented. Changes observed during room temperature spoilage have been studied with a view to present a new approach towards the assessment of freshness in fish inspection. pH of the mucin was distinctly alkaline (8.2) and remained unchanged during spoilage. Much of the nitrogen was found to be present in the glycoprotein fraction. Free amino acids and purine bases were present in appreciable quantities in the aqueous extracts which registered a significant increase after 10 hrs. Post-mortem increase in total solids was accompanied by a slight rise in protein nitrogen which may indicate tissue breakdown. Increase in TVN was also observed to occur earlier in the outside mucin as compared to the inside muscle. Presence of free sugars or sialic acid could not be confirmed nor was there any indication of cholesterol and lipoid material as stated in earlier literature.

THE ORIGIN AND GENETIC DIFFERENTIATION OF NATIVE BREEDS OF PIGS IN SOUTHWEST CHINA - AN APPROACH FROM MITOCHONDRIAL-DNA POLYMORPHISM

Mitochondrial DNA (mtDNA) of six breeds of native domestic pigs from Yunnan province, southwest China, and two wild boars obtained from Sichuan, China, and Vietnam was analyzed using 20 restriction endonucleases that recognize six nucleotides. Restriction maps were made by double-digestion methods and polymorphic sites were located on the map. According to their mtDNA restriction types, all the breeds were classified into six groups. Genetic distances among groups were calculated to define their phylogenetic relationships. The relationship between the Sichuan wild boar and domestic pigs is close, while the Vietnamese wild boar is relatively far from them, so the domestic pigs in southwest China are likely to have originated from a wild pig which distributed in west China. We compare our results with previous reports in literature and discuss the relationship among Chinese pigs, Japanese pigs, and European pigs. The mtDNA cleavage pattern of the Mingguang pig digested by EcoRV was identical to that of Duroc; mutations at the EcoRI site, detected in the mtDNA of two Dahe pigs, are the same as in the Vietnamese wild boar, suggesting that mutational hot spots exist in the mtDNA of pigs.

Development and use of parasitoids (Hymenoptera : Aphidiidae & Aphelinidae) for biological control of aphids in China

A review of aphid parasitoids in China with special emphasis on their production, utilization, and conservation is presented with a brief history of Chinese biological control. Twenty genera, 99 species of Aphidiidae and two genera, 11 species of Aphelinidae were recorded in China. Each parasitoid is listed with a brief description of aphids, host plants, areas of study such as taxonomy, biology, bionomics, geographic distribution, rearing, and literature citations. Achievements, status, and problems in aphid parasitoid production, utilization, conservation, and future prospects are detailed for dominant aphid parasitoids such as Aphidius gifuensis Ashmead, A. ervi Haliday and Aphelinus mali Haldeman. Finally, opportunities and challenges of commercialization commercialization of natural enemies, especially aphid parasitoids, in China, are analyzed and discussed.

Formant estimation of speech signals using subspace-based spectral analysis

The objective of this paper is to propose a signal processing scheme that employs subspace-based spectral analysis for the purpose of formant estimation of speech signals. Specifically, the scheme is based on decimative spectral estimation that uses Eigenanalysis and SVD (Singular Value Decomposition). The underlying model assumes a decomposition of the processed signal into complex damped sinusoids. In the case of formant tracking, the algorithm is applied on a small amount of the autocorrelation coefficients of a speech frame. The proposed scheme is evaluated on both artificial and real speech utterances from the TIMIT database. For the first case, comparative results to standard methods are provided which indicate that the proposed methodology successfully estimates formant trajectories.

Use of contexts in language model interpolation and adaptation

Language models (LMs) are often constructed by building multiple individual component models that are combined using context independent interpolation weights. By tuning these weights, using either perplexity or discriminative approaches, it is possible to adapt LMs to a particular task. This paper investigates the use of context dependent weighting in both interpolation and test-time adaptation of language models. Depending on the previous word contexts, a discrete history weighting function is used to adjust the contribution from each component model. As this dramatically increases the number of parameters to estimate, robust weight estimation schemes are required. Several approaches are described in this paper. The first approach is based on MAP estimation where interpolation weights of lower order contexts are used as smoothing priors. The second approach uses training data to ensure robust estimation of LM interpolation weights. This can also serve as a smoothing prior for MAP adaptation. A normalized perplexity metric is proposed to handle the bias of the standard perplexity criterion to corpus size. A range of schemes to combine weight information obtained from training data and test data hypotheses are also proposed to improve robustness during context dependent LM adaptation. In addition, a minimum Bayes' risk (MBR) based discriminative training scheme is also proposed. An efficient weighted finite state transducer (WFST) decoding algorithm for context dependent interpolation is also presented. The proposed technique was evaluated using a state-of-the-art Mandarin Chinese broadcast speech transcription task. Character error rate (CER) reductions up to 7.3 relative were obtained as well as consistent perplexity improvements. © 2012 Elsevier Ltd. All rights reserved.

Choosing to make an effort: the role of striatum in signaling physical effort of a chosen action.

The possibility that we will have to invest effort influences our future choice behavior. Indeed deciding whether an action is actually worth taking is a key element in the expression of human apathy or inertia. There is a well developed literature on brain activity related to the anticipation of effort, but how effort affects actual choice is less well understood. Furthermore, prior work is largely restricted to mental as opposed to physical effort or has confounded temporal with effortful costs. Here we investigated choice behavior and brain activity, using functional magnetic resonance imaging, in a study where healthy participants are required to make decisions between effortful gripping, where the factors of force (high and low) and reward (high and low) were varied, and a choice of merely holding a grip device for minimal monetary reward. Behaviorally, we show that force level influences the likelihood of choosing an effortful grip. We observed greater activity in the putamen when participants opt to grip an option with low effort compared with when they opt to grip an option with high effort. The results suggest that, over and above a nonspecific role in movement anticipation and salience, the putamen plays a crucial role in computations for choice that involves effort costs.

Comprehensive analysis of microtwins in the 3C-SiC films on Si(001) substrates

Microtwins in the 3C-SiC films grown on Si(0 0 1) by atmosphere pressure chemical vapor deposition (APCVD) were investigated in detail using X-ray four-circle diffractometry. The Phi scan shows that 3C-SiC films can grow on Si substrates epitaxially and epitaxial relationship is revealed as (0 0 1)(3C) (SiC)parallel to (0 0 1)(Si),[1 1 1](3C-SiC)parallel to [1 1 1](Si). Other diffraction peaks at about 15.8 degrees in x emerged in the pole figures of the (I 1 1) 3C-SiC. We performed the pole figure of (1 0 (1) over bar 0)h-SiC and the reciprocal space mapping from the (1 1 1) reciprocal lattice point of base SiC to the (0 0 2) point of microtwin for the first time, indicating that the diffraction peaks at 15.8 degrees in x result from not hexagonal SiC but microtwins of 3C-SiC, and twin inclusions are estimated to be around 1%. (C) 2001 Published by Elsevier Science B.V.

INTERFACIAL BEHAVIOR OF COMPATIBILIZERS IN POLYMER BLENDS

From an analysis of the literature and our experimental results, we have established that interfacial tension is a function of the concentration of a compatibilizer, and put forward a 'three-stage' physical model to account for the compatibilizing behavio

The past, present and future of phycology in China

Algae have been part of Chinese life for thousands of years. They are widely used as food and have been cited in Chinese literature as early as 2500 years ago. However, formal taxonomic studies on Chinese algae were initiated by foreign scientists only about 200 years ago, and by Chinese phycologists only about 90 years ago. This paper summarizes the history of modern phycological studies on Chinese algae and provides an overview of the achievements of phycological studies by Chinese scientists, especially on algal taxonomy, morphology, genetics, ecology and environmental research, physiology, biotechnology, algal culture, applied phycology and space phycology, in the last century. Recent development in phycological research focuses on algal floristic and molecular systematics, algal molecular biotechnology, applied phycology including micro and macroalgal cultivation and algal product development, and the roles of algae in environmental pollution control. These areas will also be the main focuses of Chinese phycological research in the foreseeable future.

Translocation of assimilates in Undaria and its cultivation in China

Undaria cultivation on a commercial scale began in China only in the last decade. Today, Undaria pinnatifida is the main species under cultivation concentrated in two provinces, Liaoning and Shandong. The annual production in the early nineties was 8000-13 000 tons dry weight, which is two or three times the pre-1980 figures. The raft cultivation method maintaining the alga at the desired depths generally ensures the light saturated rate of photosynthesis on clear days, and enhances production. Under the cultivated condition, the calculated annual primary productivity of this alga is 160 g C m(-2) y(-1). Translocation of C-14-labelled photoassimilates in rapidly growing sporophyte of Undaria pinnatifida was studied in the open sea. Samples from different parts of the blade with counterparts exposed to tracer ((NaHCO3)-C-14) showed that the translocation that occurred mainly from the tip of the blade to the growing region had obvious source-sink relationship. It took 20 minutes to translocate the labelled photoassimilates from the epidermis, via cortex, to the medulla of the midrib, where rates of translocation averaging 42-48 cm h(-1) were observed in the open sea. Production experiments of tip-cutting of the blades showed an increased production of 9%.

On the evaluation of diffusivities in gels using the diffusion cell technique

Modeling of the gel-immobilized cell system requires accurate measurement of diffusion coefficients. Three methods of the quasi-steady-state (QSS) method, the time-lag (TL) method and a variant quasi-steady-state (VQSS) method were critically assessed and compared for the evaluation of diffusivities using the diffusion cell technique. Experimental data from our laboratory were used for the analysis of the influence of crucial theoretical assumptions not being fulfilled in each method. The results highlighted a risk in obtaining highly variable diffusion coefficients by not validating the QSS and the accuracy of the measurements. In the TL method, the estimation of diffusivities based on the plot intercept that was mostly used in the literature, results in a many fold lower value when compared to that based on the plot slope. The comparison with the QSS and VQSS methods confirmed similar diffusivity obtained by the TL method based on the plot slope. It thus suggested that the correct estimation of diffusivities by the TL method could be based on the plot slope only. Furthermore, the errors associated with the solute mass in the gel, the sample withdrawal and the non-negligible concentration changes in the chambers were also discussed. It is concluded that diffusion cell technique has to be employed cautiously for a correct evaluation of diffusivities. (C) 2001 Elsevier Science B.V. All rights reserved.

'A Witty Book, but mostly feigned': William Richards' Wallography and perceptions of Wales in later seventeenth-century England

RAE2008