963 resultados para Pre-dawn leaf water potencial


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Effective processes to fractionate the main compounds in biomass, such as wood, are a prerequisite for an effective biorefinery. Water is environmentally friendly and widely used in industry, which makes it a potential solvent also for forest biomass. At elevated temperatures over 100 °C, water can readily hydrolyse and dissolve hemicelluloses from biomass. In this work, birch sawdust was extracted using pressurized hot water (PHWE) flow-through systems. The hypothesis of the work was that it is possible to obtain polymeric, water-soluble hemicelluloses from birch sawdust using flow-through PHW extractions at both laboratory and large scale. Different extraction temperatures in the range 140–200 °C were evaluated to see the effect of temperature to the xylan yield. The yields and extracted hemicelluloses were analysed to obtain sugar ratios, the amount of acetyl groups, furfurals and the xylan yields. Higher extraction temperatures increased the xylan yield, but decreased the molar mass of the dissolved xylan. As the extraction temperature increased, more acetic acid was released from the hemicelluloses, thus further decreasing the pH of the extract. There were only trace amounts of furfurals present after the extractions, indicating that the treatment was mild enough not to degrade the sugars further. The sawdust extraction density was increased by packing more sawdust in the laboratory scale extraction vessel. The aim was to obtain extracts with higher concentration than in typical extraction densities. The extraction times and water flow rates were kept constant during these extractions. The higher sawdust packing degree decreased the water use in the extractions and the extracts had higher hemicellulose concentrations than extractions with lower sawdust degrees of packing. The molar masses of the hemicelluloses were similar in higher packing degrees and in the degrees of packing that were used in typical PHWE flow-through extractions. The structure of extracted sawdust was investigated using small angle-(SAXS) and wide angle (WAXS) x-ray scattering. The cell wall topography of birch sawdust and extracted sawdust was compared using x-ray tomography. The results showed that the structure of the cell walls of extracted birch sawdust was preserved but the cell walls were thinner after the extractions. Larger pores were opened inside the fibres and cellulose microfibrils were more tightly packed after the extraction. Acetate buffers were used to control the pH of the extracts during the extractions. The pH control prevented excessive xylan hydrolysis and increased the molar masses of the extracted xylans. The yields of buffered extractions were lower than for plain water extractions at 160–170 °C, but at 180 °C yields were similar to those from plain water and pH buffers. The pH can thus be controlled during extraction with acetate buffer to obtain xylan with higher molar mass than those obtainable using plain water. Birch sawdust was extracted both in the laboratory and pilot scale. The performance of the PHWE flow-through system was evaluated in the laboratory and the pilot scale using vessels with the same shape but different volumes, with the same relative water flow through the sawdust bed, and in the same extraction temperature. Pre-steaming improved the extraction efficiency and the water flow through the sawdust bed. The extracted birch sawdust and the extracted xylan were similar in both laboratory and pilot scale. The PHWE system was successfully scaled up by a factor of 6000 from the laboratory to pilot scale and extractions performed equally well in both scales. The results show that a flow-through system can be further scaled up and used to extract water-soluble xylans from birch sawdust. Extracted xylans can be concentrated, purified, and then used in e.g. films and barriers, or as building blocks for novel material applications.

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Mentha x villosa Huds (Labiatae) is an aromatic herb widely used in folk medicine. Since the essential oil of the herb has many pharmacological activities, including antispasmodic effects, we determined whether the oil and its major constituent, piperitenone oxide (PO), have antinociceptive activity. The essential oil of M. x villosa (EOMV) and PO administered orally at 200 mg/kg (vehicle: 0.1% Tween 80 in water) significantly reduced the writhings induced by acetic acid from control values of 59.5 ± 3.1 s (N = 10) to 31.9 ± 2.8 s (N = 10) and 23.8 ± 3.4 s (N = 10), respectively. When administered at 100 and 200 mg/kg, EOMV reduced the paw licking time for the second phase of the formalin test from the control value of 20.6 ± 2.1 s (N = 13) to 5.3 ± 2.2 s (N = 12) and 2.7 ± 1.2 s (N = 18), respectively. At 100 and 200 mg/kg, PO reduced this second phase to 8.3 ± 2.7 s (N = 12) and 3.0 ± 1.2 s (N = 10), respectively. This effect of EOMV and PO was not reversed by naloxone. EOMV and PO had no significant effect on the first phase of the formalin test. As evaluated by the hot-plate and tail immersion test, EOMV and PO, at doses up to 200 mg/kg, showed no analgesic activity. These results show that EOMV and PO have antinociceptive activity and suggest that this effect is probably an indirect anti-inflammatory effect, which does not involve the central nervous system.

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The relationship of NaCl with problems of arterial hypertension has led to a reduction in the levels of this salt in food production. KCl has been used as a partial substitute for NaCl since it cannot be completely substituted without affecting the acceptability of the end product. In this study, the diffusion that occurs during quail egg salting in static and stirred brine was simulated. The mathematical model used was based on a generalization of the Fick's 2nd law, and the COMSOL Multiphysics software was used to simulate the diffusion in the NaCl-KCl-water system. The deviations in the simulated data and experimental data were 2.50% for NaCl and 6.98% for KCl in static brine, while in the stirred brine they were 3.48% for NaCl and 4.72% for KCl. The simulation results presented good agreement with the experimental values and validated the predictive capacity of the model.

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The objective of this study was to develop a pre-gelatinized flour using a mixture of broken rice and split beans by thermoplastic extrusion, and to evaluate the physicochemical, nutritional, and technological quality of the final product. The extrusion parameters were maintained using three heating zones with temperatures of 30 ºC, 40 ºC, and 70 ºC; screw speed of 177 rpm; feed rate of 257 g/m, and circular matrix of 3.85 mm. The following characterization analyses were performed: physicochemical, nutritional, water absorption index (WAI), water solubility index (WSI), and paste viscosity. The pre-gelatinized rice and bean flour had an intermediate value of WAI, 7.51 g/g, and high WSI value, 24.61%. Regarding proteins, it was verified an average content of 12.9% in the final product. The amino acid contents found in the pre-gelatinized flour indicate that the mixture has the essential amino acids. It was also found that the pre-gelatinized flour supplies more than 60% of the essential amino acids recommended for children aged one to three years old. The gelatinized flour composed of broken rice and split beans is an alternative to the use of these by-products of the manufacture process of rice and beans to obtain a product with viable technological characteristics and high nutritional value.

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The mixture of Brazil nut flour and green banana flour can improve the nutritional value of school meals, allowing for the use of regional ingredients derived from family agriculture. This study aimed to assess the stability of porridge pre-mixtures made with Brazil nut flour and green banana flour during six months of storage. Two types of pre-mixture were evaluated: with and without milk powder. These mixtures were packed in polyethylene/metallized polyester film, vacuum-sealed, and stored at room temperature. The products were evaluated for physicochemical composition, and every 30 days for moisture content, water activity, titratable acidity, pH, peroxide value and acidity of the lipid phase, total and thermotolerant coliforms, yeasts and molds, and sensory acceptance. There was no difference between the mixtures for the parameters evaluated. Moisture content, water activity, acidity of the lipid phase, and the yeast and mold count increased with storage time. The growth of yeasts and molds was more pronounced after 90 days of storage, when water activity reached the limit of 0.60. Although both products had good sensory acceptance throughout the period of study, it is recommended that the shelf life does not exceed 90 days.

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The experiment was carried out in pots in a glasshouse, with one plant per pot and nine repetitions per treatment. The treatments consisted of free or restricted leaves, submited to 90-100% or 60-70% soil field capacity (FC). Only independent effects of water availability or leaf movement were observed on yield components. Plants under well-watered conditions and with freely orienting leaves were taller, and had a larger number of ramifications. The greater development favored the setting of a higher number of inflorescences per plant in these treatments. This behavior resulted in a high number of flowers, green and mature legumes per plant, thus resulting in high seed production which was the most evident response to water availability. Although individual seed weight was higher in the water stress treatment, total seed production was higher for well-watered plants, with no statistically significant effect of leaf movements.

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Soybeans grown under water stress associated with high temperatures during seed maturation and pre-harvest may produce green seed (GS) with expressive reduction in seed quality. The objectives of this study were to evaluate the response of different soybean cultivars grown under these stressful conditions regarding their susceptibility to GS production and to determine the chlorophyll retention levels and the chlorophyllase activity in the seeds. Seeds of four soybean cultivars [BRS 133, CD 206, MG/BR 46 (Conquista) and BRSMG 251 (Robusta)] were grown under greenhouse conditions until R5.5. At R6, the plants were transferred to phytotrons under temperature stress (from 28ºC to 36ºC) and with water stresses of 10% gravimetric moisture, no water and normal supply. Seeds were harvested at R9 when the percentage of GS and weight of 100 seeds were determined. The contents of a, b and total chlorophylls and the chlorophyllase activity were also determined. The expression of GS production under these conditions varied among cultivars: Conquista and Robusta were considered more susceptible to the production of GS compared to 'BRS 133' and 'CD 206'. These cultivars produced lower GS levels, lower chlorophyll retention and higher chlorophyllase activity compared to Robusta and Conquista. Soybean plants submitted to water and temperature stresses produced high levels of GS, which were small, light and had high chlorophyll contents and low chlorophyllase activity. The contents of a, b and total chlorophylls in GS were inversely proportional to the chlorophyllase activity.

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The objective of this study was to evaluate the effects of temperature, substrate and pre-germinative treatments on T. triangulare seeds. Four temperatures (constant 20, 25, 30 °C and alternate 20-30 °C) and two types of seeding (on paper and between paper), with light, were evaluated. The pre-germinative treatments evaluated included: immersion in water (24 hours), immersion in 6% hypochlorite solution (1 hour), immersion in 0.2% potassium nitrate solution (24 hours), immersion in 0.05% gibberellin solution (24 hours) and the control (untreated seeds). The highest germination percentage was observed at the alternate temperatures of 20-30 ºC, but with no significant difference between the substrates at this temperature. Soaking seeds in KNO3 gave the highest percentage germination and germination speed index (GSI), which differed from the other treatments except for soaking in water. Pre-soaking of T. triangulare seeds favors germination and may be done only in pure water, resulting in a more rapid and uniform germination.

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An efficient way of synthesizing the deuterium labelled analogues of three methoxypyrazine compounds: 2-d3-methoxy-3-isopropylpyrazine, 2-d3-methoxy-3- isobutylpyrazine, and 2-d3-methoxy-3-secbutylpyrazine, has been developed. To confirm that the deuterium labels had been incorporated into the expected positions in the molecules synthesized, the relevant characterization by NMR, HRMS and GC/MS analysis was conducted. Another part of this work involved quantitative determination of methoxypyrazines in water and wines. Solid-phase extraction (SPE) proved to be a suitable means for the sample separation and concentration prior to GC/MS analysis.Such factors as the presence of ethanol, salt, and acid have been investigated which can influence the recovery by SPE for the pyrazines from the water matrix. Significantly, in this work comparatively simple fractional distillation was attempted to replace the conventional steam distillation for pre-concentrating a sample with a relatively large volume prior to SPE. Finally, a real wine sample spiked with the relevant isotope-labelled methoxypyrazines was quantitatively analyzed, revealing that the wine with 10 beetles per litre contained 138 ppt of 2-methoxy-3-isopropylpyrazine. Interestingly, we have also found that 2-methoxy-3-secbutylpyrazine exhibits an extremely low detection limit in GC/MS analysis compared with the detection limit of the other two methoxypyrazines: 2- methoxy-3-isopropylpyrazine and 2-methoxy-3-isobutylpyrazine.

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Niagara Peninsula of Ontario is the largest viticultural area in Canada. Although it is considered to be a cool and wet region, in the last decade many water stress events occurred during the growing seasons with negative effects on grape and wine quality. This study was initiated to understand and develop the best strategies for water management in vineyards and those that might contribute to grape maturity advancement. The irrigation trials investigated the impact of time of initiation (fruit set, lag phase and veraison), water replacement level based on theoretical loss through crop evapotranspiration (ETc; 100,50 and 25%) and different irrigation strategies [partial root zone drying (PRD) versus regulated deficit irrigation (RD!)] on grape composition and wine sensory profiles. The irrigation experiments were conducted in a commercial vineyard (Lambert Vineyards Inc.) located in Niagara-on-the-Lake, Ontario, from 2005 through 2009. The two experiments that tested the combination of different water regimes and irrigation time initiation were set up in a randomized block design as follows: Baco noir - three replicates x 10 treatments [(25%, 50% and 100% of ETc) x (initiation at fruit set, lag phase and veraison) + control]; Chardonnay - three replicates x seven treatments [(25%, 50% and 100% of ETc) x (initiation at fruit set and veraison) + control]. The experiments that tested different irrigation strategies were set up on two cultivars as follows: Sauvignon blanc - four replicates x four treatments [control, fully irrigated (100% ETc), PRD (100% ETc) and RDI (25% ETc)]; Cabemet Sauvignon - four replicates x five treatments [control, fully irrigated (100% ETc), PRD (100% ETc), RDI (50% ETc) and RDI (25% ETc)]. The controls in each experiment were nonirrigated. The irrigation treatments were compared for many variables related to soil water status, vine physiology, berry composition, wine sensory profile, and hormone composition [(abscisic acid (ABA) and its catabolites]. Soil moisture profile was mostly affected by irrigation treatments between 20 and 60 em depth depending on the grapevine cultivar and the regime of water applied. Overall soil moisture was consistently higher throughout the season in 100 and 50% ETc compare to the control. Transpiration rates and leaf temperature as well as shoot growth rate were the most sensitive variables to soil water status. Drip irrigation associated with RDI treatments (50% ETc and 25% ETc) had the most beneficial effects on vine physiology, fruit composition and wine varietal typicity, mainly by maintaining a balance between vegetative and reproductive parts of the vine. Neither the control nor the 100 ETc had overall a positive effect on grape composition and wine sensory typicity. The time of irrigation initiation affected the vine physiology and grape quality, the most positive effect was found in treatments initiated at lag phase and veraison. RDI treatments were overall more consistent in their positive effect on grape composition and wine varietal typicity comparing to PRD treatment. The greatest difference between non-irrigated and irrigated vines in most of the variables studied was found in 2007, the driest and hottest season of the experimental period. Soil water status had a greater and more consistent effect on red grapevine cultivars rather than on white winegrape cultivars. To understand the relationships among soil and plant water status, plant physiology and the hormonal profiles associated with it, abscisic acid (ABA) and its catabolites [phaseic acid (PA), dihydrophaseic acid (DPA), 7-hydroxy-ABA (TOH-ABA), 8' -hydroxy-ABA, neophaseic acid and abscisic acid glucose ester (ABA-GE)] were analyzed in leaves and berries from the Baco noir and Chardonnay irrigation trials over two growing seasons. ABA and some of its catabolites accurately described the water status in the vines. Endogenous ABA and some of its catabolites were strongly affected in Baco noir and Chardonnay by both the water regime (i.e. ET level) and timing of irrigation initiation. Chardonnay grapevines produced less ABA in both leaves and berries compared to Baco noir, which indicated that ABA synthesis is also cultivar dependant. ABA-GE was the main catabolite in treatments with high water deficits, while PA and DPA were higher in treatments with high water status, suggesting that the vine produced more ABA-GE under water deficits to maintain rapid control of the stomata. These differences between irrigation treatments with respect to ABA and catabolites were particularly noticeable in the dry 2007 season. Two trials using exogenous ABA investigated the effect of different concentrations of ABA and organs targeted for spraying, on grape maturation and berry composition of Cabemet Sauvignon grapevines, in two cool and wet seasons (2008-2009). The fIrst experiment consisted of three replicates x three treatments [(150 and 300 mg/L, both applications only on clusters) + untreated control] while the second experiment consisted in three replicates x four treatments [(full canopy, only clusters, and only leaves sprayed with 300 ppm ABA) + untreated control]. Exogenous ABA was effective in hastening veraison, and improving the composition of Cabemet Sauvignon. Ability of ABA to control the timing of grape berry maturation was dependant on both solution concentration and the target organ. ABA affected not only fruit composition but also yield components. Berries treated with ABA had lower weight and higher skin dry mass, which constitutes qualitative aspects desired in the wine grapes. Temporal advancement of ripening through hormonal control can lead to earlier fruit maturation, which is a distinct advantage in cooler areas or areas with a high risk of early frost occurrence. Exogenous ABA could provide considerable benefits to wine industry in terms of grape composition, wine style and schedule activities in the winery, particularly in wet and cool years. These trials provide the ftrst comprehensive data in eastern North America on the response of important hybrid and Vitis vinifera winegrape cultivars to irrigation management. Results from this study additionally might be a forward step in understanding the ABA metabolism, and its relationship with water status. Future research should be focused on ftnding the ABA threshold required to trigger the ripening process, and how this process could be controlled in cool climates.

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La présente contribution examine les fondements normatifs ainsi que les implications éthiques du droit à l’eau, tel qu’il fut reconnu en 2002 par le comité onusien des droits économiques, sociaux et culturels. Il sera défendu que le droit à l’eau potable peut être justifié en tant que droit moral fondamental, de par son caractère indispensable en vue de la garantie des conditions basiques de survie. Cet état de fait, cependant, s’avère moins évident au vue d’un droit à l’eau d’usage non-domestique. Ici, la discussion se rapproche des débats accompagnant le concept beaucoup plus complexe des droits sociaux et économiques. Par rapport à ce groupe de droits, la question de l’allocation est des plus controversées: à qui incombe-t-il de garantir leur respect? Dans le but d’éviter cette problématique d’allocation, le présent essai soulèvera la question de savoir, si la limitation de l’accès à l’eau peut être conçue comme une violation d’autres droits moraux: bien qu’il y ait des cas où des entreprises transnationales déploient des activités nuisibles à l’égard des populations pauvres en polluant sciemment leurs ressources en eau ou en initiant et en exécutant des stratégies de privatisation les privant de leurs droits, la crise globale de l’eau ne saura être rattachée uniquement aux effets de la mondialisation. Plutôt, l’on reconnaîtra la nécessité d’efforts positifs et soutenus de la part des pays développés en vue de la réalisation d’un approvisionnement suffisant en eau pour tous.

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Nous avons utilisé une approche ethnobotanique pour identifier des espèces de plantes utilisées par les Cris afin de traiter les symptômes du diabète de type 2. Larix laricina du Roi (L. laricina) a récemment été identifiée comme une des meilleures plantes qui a stimulé le transport de glucose dans les cellules C2C12 et fortement potentialisé la différenciation des 3T3-L1 en indiquant une sensibilité potentiellement accrue à l’insuline. Ensuite, ces études de criblage ont été effectuées sur des extraits éthanolique (EE) en utilisant une série de bioessais in vitro. Cependant, les préparations traditionnelles des plantes sont souvent faites avec l’eau chaude. Le but de cette thèse de doctorat était d’isoler les principes actifs de L. laricina par un fractionnement guidé par l’adipogenèse; d’évaluer et de comparer l’activité et les mécanismes antidiabétiques des EE et des extraits aqueux (HWE) de ces 17 plantes. Pour le fractionnement de L. laricina, on a isolé plusieurs composés connus et identifié un nouveau composé actif cycloartane triterpene, qui a amélioré fortement l’adipogenèse et a été responsable en partie de l’activité adipogénique (potentiellement similaire à l’effet sensibilisateur à l’insuline des glitazone) de l’extrait éthanolique issu de l’écorce de L. laricina. Pour le métabolisme lipidique, nos résultats ont confirmé que 10 parmi les 17 EE ont augmenté la différenciation des adipocytes alors que 2 extraits seulement l’ont inhibée. Les HWE ont montré une faible activité adipogénique ou antiadipogénique. Les EE de R. groenlandicum et K. angustifolia ont le PPAR γ (peroxisome proliferator-activated receptor γ), le SREBP-1 (sterol regulatory element binding protein-1) et le C/EBP (CCAAT-enhancer binding proteins) α, alors que ceux de P. balsamifera et A. incana les ont inhibés. L’effet inhibiteur de P. balsamifera a également été prouvé d’avoir impliqué l’activation de la protéine kinase activée par l’AMP (AMPK). Les EE et HWE de R. groenlandicum ont stimulé les mêmes facteurs de transcription alors que les extraits aqueux d’autres plantes sélectionnées ont perdu ces effets en comparaison avec leurs extraits éthanoliques respectifs. L’analyse phytochimique a également identifié le groupe des espèces actives et inactives, notamment lorsque les espèces ont été séparées par famille de plante. Finalement concernant l’homéostasie de glucose, nos résultats ont confirmé que plusieurs EE ont stimulé le transport de glucose musculaire et inhibé l’activité de la glucose-6-phosphatase (G6Pase) hépatique. Certains des HWE ont partiellement ou complètement perdu ces activités antidiabétiques par rapport aux EE, tandis qu’une seule plante (R.groenlandicum) a juste conservé un potentiel similaire entre les EE et HWE dans les deux essais. Dans les cellules musculaires, les EE de R.groenlandicum, A. incana et S. purpurea ont stimulé le transport de glucose en activant la voie de signalisation de l’AMPK et en augmentant le niveau d’expression des GLUT4. En comparaison avec les EE, les HWE de R.groenlandicum ont montré des activités similaires; les HWE de A. incana ont complètement perdu leur effet sur tous les paramètres étudiés; les HWE de S. purpurea ont activé la voie de l’insuline au lieu de celle de l’AMPK pour augmenter le transport de glucose. Dans les cellules H4IIE, les EE et HWE des 5 plantes ont activé la voie de l’AMPK, et en plus les EE et HWE de 2 plantes ont activé la voie de l’insuline. La quercétine-3-O-galactoside et la quercétine 3-O-α-L-arabinopyranoside ont été identifiées comme des composés ayant un fort potentiel antidiabétique et donc responsables de l'activité biologique des plantes HWE actifs avec le transport du glucose. En conclusion, on a isolé plusieurs composés connus et identifié un nouveau triterpène actif à partir du fractionnement de L. laricina. Nous avons fourni également une preuve directe pour l'évaluation et la comparaison d'une action analogue à l'insuline ou insulino-sensibilisateur des EE et HWE de plantes médicinales Cris au niveau de muscle, de foie et de tissus adipeux. Une partie de leur action peut être liée à la stimulation des voies de signalisation intracellulaire insulino-dépendante et non-insulino-dépendante, ainsi que l’activation de PPARγ. Nos résultats indiquent que les espèces de plantes, les tissus ou les cellules cibles, ainsi que les méthodes d'extraction sont tous des déterminants significatifs de l'activité biologique de plantes médicinales Cris sur le métabolisme glucidique et lipidique.

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Shrimp Aquaculture has provided tremendous opportunity for the economic and social upliftment of rural communities in the coastal areas of our country Over a hundred thousand farmers, of whom about 90% belong to the small and marginal category, are engaged in shrimp farming. Penaeus monodon is the most predominant cultured species in India which is mainly exported to highly sophisticated, quality and safety conscious world markets. Food safety has been of concem to humankind since the dawn of history and the concern about food safety resulted in the evolution of a cost effective, food safety assurance method, the Hazard Analysis Critical Control Point (HACCP). Considering the major contribution of cultured Penaeus monodon to the total shrimp production and the economic losses encountered due to disease outbreak and also because traditional methods of quality control and end point inspection cannot guarantee the safety of our cultured seafood products, it is essential that science based preventive approaches like HACCP and Pre requisite Programmes (PRP) be implemented in our shrimp farming operations. PRP is considered as a support system which provides a solid foundation for HACCP. The safety of postlarvae (PL) supplied for brackish water shrimp farming has also become an issue of concern over the past few years. The quality and safety of hatchery produced seeds have been deteriorating and disease outbreaks have become very common in hatcheries. It is in this context that the necessity for following strict quarantine measures with standards and code of practices becomes significant. Though there were a lot of hue and cry on the need for extending the focus of seafood safety assurance from processing and exporting to the pre-harvest and hatchery rearing phases, an experimental move in this direction has been rare or nil. An integrated management system only can assure the effective control of the quality, hygiene and safety related issues. This study therefore aims at designing a safety and quality management system model for implementation in shrimp farming and hatchery operations by linking the concepts of HACCP and PRP.

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A detailed study of the hydrography of the Cochin Backwaters, the habitat off crassostrea madrasensis has been carried out. Data pertaining to air temperature, water temperature, salinity, dissolved oxygen, turbidity and rainfall have been collected and presented. The temperature fluctuation was in the range of 5°C only and that of salinity between 1.1%o and 32.9%o. Fairly steady salinity has been recorded during the pre-monsoon period (February to May) and drastic declension during the monsoon period (June-September).Dissolved oxygen varied between 2.5 ml/l and 6.5 ml/l. Turbidity was highest in June (27.9 p.p.m.) and minimum (10.2 p.p.m.) in February. A detailed study on marine biofouling in the Cochin Backwaters has been made with special reference to primary film, settlement and growth of the fouling organisms such as hydroids, bryozoans, tube-dwelling polychaetes, barnacles and modiolus

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The Kerala Water Authority requested the School of Environmental Studies to carry out investigations on the mechanism of sporadic mobilization of iron and odour in the raw water drawn to the drinking water treatment plant. The currently used treatment process failed to remove iron completely. This led to problems in the filter and complaints of taste and colour due to iron in the finished water. The sporadic nature of the problem itself made the trouble shooting difficult. The problem was looked in from three points of view. 1. Influence of environmental (climatic) conditions on the dynamics of the relevant basin of the reservoir. 2. Influence of the physical dynamics on the physico — chemical quality of water. 3. Identification of cost-effective treatment processes to suit the existing plant. Since the problem emerged only during the post- monsoon to pre-monsoon months, a related problem was investigated, namely, influence of anions on the oxidation of Fe(II) in natural waters by air. This is presented in Part II of the dissertation.