Evaluation of quality of shark livers using bio-chemical properties and organoleptic score sheet

Shark livers are considered as an important raw material providing a quality fish oil. It has been reported to aid white — blood-cell production and act as an active ingredient in hemorrhoid treatments. It is also reported that liver oil as a good supplement of vitamin A and poly-unsaturated fatty acids which are important to the development of brain cells in human. Freshness of livers is very important to extract better quality oil. In Sri Lanka, the annual shark production amounts to 8000t, however the quality of livers collected from landing sites has not being measured yet. Present study was conducted to evaluate the quality of silky (Charcarninus fakiformis) shark livers available in Negombo and Beruwala landing sites in the West Coast of Sri Lanka and also to study the relationship between organoleptic and bio-chemical correlation on freshness of shark livers. Liver samples which were collected from landing sites in the West coast of Sri Lanka, were evaluated for external and internal colour, texture and odour. Total volatile nitrogen (TVN), pH value, free fatty acid (FFA%) and peroxide (PV) values of livers were also determined to assess quality. According to the organoleptic scoring system 4.3% of liver samples were categorized as best in quality while 30.4%, 56.5% and 8.7% rated as good, medium and poor in quality respectively at the Negombo and Beruwala landing sites. Bio-chemical analysis showed that the better quality livers had the highest score for sensory evaluation and low values for TVN, FFA and peroxide value while low quality livers gave low score for sensory evaluation and high TVN, FFA, peroxide values. Correlation coefficient of organoleptic scores against total volatile nitrogen value, pH value, free fatty acid % and peroxide value of shark livers were determined by statistical analysis. Organoleptic score of shark livers was found to be highly.

Dissecting Arabidopsis thaliana DICER function in small RNA processing, gene silencing and DNA methylation patterning.

Small RNAs have several important biological functions. MicroRNAs (miRNAs) and trans-acting small interfering RNAs (tasiRNAs) regulate mRNA stability and translation, and siRNAs cause post-transcriptional gene silencing of transposons, viruses and transgenes and are important in both the establishment and maintenance of cytosine DNA methylation. Here, we study the role of the four Arabidopsis thaliana DICER-LIKE genes (DCL1-DCL4) in these processes. Sequencing of small RNAs from a dcl2 dcl3 dcl4 triple mutant showed markedly reduced tasiRNA and siRNA production and indicated that DCL1, in addition to its role as the major enzyme for processing miRNAs, has a previously unknown role in the production of small RNAs from endogenous inverted repeats. DCL2, DCL3 and DCL4 showed functional redundancy in siRNA and tasiRNA production and in the establishment and maintenance of DNA methylation. Our studies also suggest that asymmetric DNA methylation can be maintained by pathways that do not require siRNAs.

Understanding and communicating the value of technology: A process perspective

Technological investment is an important driver of innovation and the evaluation of technology potential is becoming increasingly important in this context. Although there is a range of possible approaches and tools for understanding and communicating the value of technology to potential customers, not all are useful or accessible in practice, where the situation is often complex and constantly evolving. Although many companies have their own customised processes in place for securing approval for technology development, often combining several techniques, very few empirical studies have been performed to learn from these practices and provide an overall view of the process of ";selling"; technologies internally or externally. In this paper, the current literature and practice related to technology valuation is reviewed and summarised in a five step process for building a business case for technology investment that gives guidance on where and when to use specific valuation tools. The seller or proposer's perspective is taken and consultative sales techniques incorporated. This provides a flexible reference for R&D managers and adds to the body of literature on the selection and use of valuation tools. A user friendly guide has been published detailing the five step approach. © 2011 IEEE.

Development and shelf life evaluation of Tilapia (Orechromis spp.) marinades

Tilapia (Oreochromis spp.) consumption is limited due to its strong muddy odour and the difficulty of processing. In addition, consumption of tilapia is minimal in urban areas because of the low availability. There are no processed market products of tilapia available in Sri Lanka. Therefore, this study was designed to develop a new marinade for tilapia and to evaluate the shelf life of the product. Twelve different treatments of varying amounts of vinegar, salt, chili powder, white pepper and garlic powder were applied to filleted tilapia, and three best treatment combinations were selected using a sensory evaluation test. Processed tilapia was stored in the freezer at -4°C. Treated samples were subjected to evaluation of sensory profile: taste, odour, colour, texture and overall acceptability. Analysis of the shelf life was carried out by using the total plate count, faecal coliform test, acidity and pH at weekly intervals. Results revealed that the third treatment (vinegar 75 ml, salt 5 g, chili powder 5 g, white pepper 5 g and garlic powder 5 g) was best in terms of colour, texture, odour, taste and the overall acceptability according to the estimated medians (6, 6, 6 and 6.33 respectively). There was no significant difference between the first and the third treatment in terms of odour and overall acceptability. There was no significant difference between the three vacuum packed treatments for acidity and pH. Acidity and pH of the three treatments were at an acceptable level, which was below pH 5.3 and above 1.95% acidity. Average bacterial count was 10 colonies and 1.33x10 super(6) colonies respectively in vacuum packed treatments and bottled samples after one week. The acceptable level of bacterial colonies is 1.00x10 super(5). Vacuum packed treatments showed a one month shelf life. In conclusion, marinades can be developed from tilapia with a pleasant taste and acceptable texture.

An assessment of handling and processing methods used for the shrimp fishery by-catch in Kalpitiya, Sri Lanka

The by-catch from the shrimp trawl fishery in Kalpitiya is mainly used for the production of dried fish, which provides an additional source of income for fishermen in the area. It has been observed that current handling practices along the value addition chain are responsible for the poor quality and low price of the end product. This study was aimed at identifying the shortcomings in such handling practices by fishermen and dried fish producers and assessing the quality of shrimp fishery by-catch along the processing chain in order to recommend more efficient utilization methods that will improve the quality of the end product. Fresh fish, dried fish and harbour water samples were tested for total coli forms, faecal coliforms, E. coli and Salmonella in order to assess their microbial quality: In addition, standard plate counts (SPC) of fish samples were also carried out. A survey was carried out from July-October 2006 at Kalpitiya, using a pre-tested questionnaire to collect information from individuals who have been engaged in dried fish processing. Average values obtained for freshly landed and dried fish respectively, were, SPC 9.88x10 super(5) CFU/g and 30.43x10 super(5) CFU/g, total coliforms 23.05 and 24.23 MPN/g and fecal coliforms 8.28 and 9.00 MPN/g. These values exceed the recommendations in the SL standards. A quarter of the landed fresh fish and 38% of dried fish from the producers were positive for E. coli and thus failed to show required end product quality. SPC of harbour water was 14.35x10 super(6) CFU/ml and all samples were found to be contaminated with E. coli. None of the fishermen and dried fish producers were satisfied with the quality of the end product. The reasons for poor quality as indicated by them were: limited availability of ice (75%), lack of infrastructure facilities (65%), uncertainty of markets (52%), lack of emphasis on quality (47%) and poor access to available technologies (41%). Respondents to the questionnaire also identified: unavailability of potable water, insulated boxes, good landing jetty, racks for drying fish, poor cold storage facilities and limitations in dried fish storage facilities, as further factors leading to the loss of quality in their products. Results demonstrate that improvements to the infrastructure facilities and conducting of proper awareness programmes on handling practices could lead for improvements in the quality of value added products prepared from the shrimp fishery by-catch at Kalpitiya.

Morphometric analysis of Macaca arctoides and M-thibetana in relation to other macaque species

As a first step in reviewing the classification of the two stump-tailed macaque species, Macaca arctoides and M. thibetana, as compared with other species of the genus Macaca, 72 linear dental and cranial variables of 11 macaque species were examined by morphometric analyses. The results indicate that the two stump-tailed species are the largest of the macaques and although rather similar overall, they exhibit significant differences in the pattern of variation in most of the five skull regions as shown by Principal Components and Canonical Variate Analyses. Euclidean Distances based on Canonical Variate scores indicate that the females of M. arctoides and M. thibetana are more widely separated than eight other pairs of macaque species, and that the separations of the respective males are greater than those of three other pairs of species. These findings are consistent with FOODEN's classification of the stump-tailed macaques as two separate species (FOODEN, 1976; FOODEN et al., 1985). The present results suggest, as other researchers have proposed on the basis of external features, biochemistry and genetics, that the two stump-tailed macaque species and M. assamensis are closely related. The results also tentatively imply associations with M. fuscata and M. sylvanus but these require further study. The findings have implications for the assessment of the various Chinese Pleistocene macaque fossils.

动物体节发生模型及其相关基因研究进展

脊椎动物在胚胎发育的过程中沿身体前后轴形成一定数目的暂时性结构-体节(somite),随着胚胎的继续发育每个体节分化成为生骨区、生皮区和生肌区,继而生成各种组织。近30年来,研究者们就体节的发生和分化提出了多种解释模型,这包括时钟波峰模型、反应扩散模型、时钟诱导模型、时钟痕迹模型等,这些模型从不同角度不同程度解释了动物体节发生和分化的不同现象。尽管每个模型仍然存在一些不足,但大多提出了时钟分节(segmental clock)这一概念。对鸡的c-hairy1和c-hairy2、鸡和小鼠的l-fng以及斑马

Slowness: an objective for spike-timing-dependent plasticity?

Our nervous system can efficiently recognize objects in spite of changes in contextual variables such as perspective or lighting conditions. Several lines of research have proposed that this ability for invariant recognition is learned by exploiting the fact that object identities typically vary more slowly in time than contextual variables or noise. Here, we study the question of how this "temporal stability" or "slowness" approach can be implemented within the limits of biologically realistic spike-based learning rules. We first show that slow feature analysis, an algorithm that is based on slowness, can be implemented in linear continuous model neurons by means of a modified Hebbian learning rule. This approach provides a link to the trace rule, which is another implementation of slowness learning. Then, we show analytically that for linear Poisson neurons, slowness learning can be implemented by spike-timing-dependent plasticity (STDP) with a specific learning window. By studying the learning dynamics of STDP, we show that for functional interpretations of STDP, it is not the learning window alone that is relevant but rather the convolution of the learning window with the postsynaptic potential. We then derive STDP learning windows that implement slow feature analysis and the "trace rule." The resulting learning windows are compatible with physiological data both in shape and timescale. Moreover, our analysis shows that the learning window can be split into two functionally different components that are sensitive to reversible and irreversible aspects of the input statistics, respectively. The theory indicates that irreversible input statistics are not in favor of stable weight distributions but may generate oscillatory weight dynamics. Our analysis offers a novel interpretation for the functional role of STDP in physiological neurons.

The process of making the business case for technology: A sales and marketing perspective for technologists

Technological investment is a key driver of innovation and the evaluation of technology potential is becoming increasingly important in this context. There is a range of approaches and tools for developing an understanding of the value of technology. However the process of communicating this potential to possible customers is not well documented in terms of theory and practice and falls outside the skill set of many technologists. This paper seeks to integrate the concepts of marketing and consultative selling into making business cases for new technologies. It describes an exploratory study which results in an outline process activity model for technologists wishing to build an effective business case for securing investment internally or when selling a technology externally. Following a review of literature, we suggest that there is potential to learn from market research and consultative sales techniques, and propose a five step process. The work has been industrially validated and forms a novel foundation for further development. © 2012 Elsevier Inc.

Optically activated shutter using a photo-tunable short-pitch chiral nematic liquid crystal

We report the demonstration of an optically activated shutter based upon a short-pitch chiral nematic liquid crystal (LC) device sandwiched between crossed polarizers. This LC is comprised of photo-active chiral dopants. In the trans-state, the LC appears dark between crossed polarizers due to the very short pitch. As the pitch is extended through exposure to ultraviolet light, the device becomes transmissive reaching a maximum for a particular value of the pitch. As a result, it is possible to switch between the light and dark states by subjecting the device to visible light so as to cause a cis-trans photo-isomerisation. © 2013 AIP Publishing LLC.