− The intensity, structure and variability of the slope current have been determined from 16 months of observations with Acoustic Doppler Current Profilers (ADCP) and conventional current meters on a cross-slope section at the Hebridean shelf edge during the Shelf Edge Study (SES) programme. After removal of the tidal signals, the mean flow over the upper slope is found to be closely parallel to the topography with speeds of ≈ 20 cm·s -1 . The flow extends down to a depth of 500 m and is predominantly barotropic, especially in winter when the flow is practically uniform between 350 m and the surface. In summer, there is a significant baroclinic component with a pronounced maximum in current at a depth of about 200 m but more than 80% of the kinetic energy is in the barotropic component. Flow in the core of the current is highly persistent with the Neumann's steadiness St > 0.8 in summer. In winter the flow is generally more energetic and variable and extends onto the adjacent shelf. The cross-slope profile of sea surface elevation, computed from the mean barotropic currents, shows a consistent relation to seabed topography through the seasonal cycle. Long-term averages of the cross-slope components are generally small (≈ 2 cm·s -1 ) with some indication of persistent down-slope flow in the bottom Ekman layer. Measurements with shipboard ADCP on sections at intervals along the slope show a high degree of continuity in the structure of the flow. The core of the flow appears to be related to a weak positive salinity anomaly and a depression of the 9.5°C isotherm near the shelf, but there is no strong correlation between the core of the slope-current and the core of the salinity anomaly. It is proposed that this may be due to differences in the cross-stream diffusion of salt and momentum which have different boundary conditions at the slope. The observed cross-stream structure of the current supports the hypothesis that JEBAR is the principal forcing mechanism but the result cannot be regarded as conclusive since a uniform potential vorticity model of the flow produces a similar cross-sectional structure of the current. OCEANOLOGICA ACTA ⋅ VOL. 24 -Supplement long du cycle saisonnier. Les moyennes à long terme des composantes du courant transversal au talus sont généralement faibles (≈ 2 cm·s -1 ) et rèvèlent un flux descendant persistant au bas de la couche d'Ekman. La courantométrie sur des sections transversales au talus continental indique que la structure du flux est fortement continue. La veine centrale du courant semble associée à une légère anomalie positive de la salinité et à une dépression de l'isotherme de 9,5°C près du plateau continental, mais sans corrélation marquée entre les positions du courant et de l'anomalie en sels. Cela pourrait être du aux différences entre le moment et la diffusion des sels à travers les courants, tous deux présentant des conditions aux limites distinctes sur la talus continental. La structure transversale du courant confirme l'hypothèse selon laquelle JEBAR est le ...

MYB transcription factor genes play important roles in developmental and various other processes in plants. In this study, functional characterization of AmMYB1, a single-repeat MYB transcription factor isolated from the salt-tolerant mangrove tree Avicennia marina is reported. AmMYB1 cDNA was 1046 bp in length with an open reading frame of 783 bp, encoding 260 amino acids. The corresponding gene had two introns and three exons and was present as a single copy in A. marina. The deduced amino acid sequence showed similarities to MYB proteins reported in other plants, including the conserved MYB binding domain. RNA gel blot analysis showed that the AmMYB1 transcript expression was more pronounced in green photosynthetic tissue and was strongly induced by stresses such as salt (500 mM), light (500 µE m(-2) s(-1)), and the exogenous application of ABA (100 µM). An analysis of the upstream sequence of AmMYB1 gene revealed the presence of regulatory elements identical to those present in the promoters of stress inducible genes. The promoter was responsive to NaCl and could enhance reporter gene expression in planta. An in vitro DNA binding assay using the promoter region (TGGTTAG) of the AtRD22 gene and a transactivation assay in yeast cells suggest the possibility of AmMYB1 protein regulating the expression of other genes during salt stress. Transgenic tobacco plants constitutively expressing the AmMYB1 transcription factor showed better tolerance to NaCl stress.

Based on the annual length frequency data collected from three major fish landing centres along the River Periyar, draining the southern Western Ghats, the von Bertalanffy growth function (VBGF) estimates of Horobagrus brachysoma were worked out as asymptotic length (L a ) = 422mm total length, growth co-efficient (K) = 0.55 yr -1 and growth performance index (ø) = 4.99. The total mortality rate (Z) was estimated at 5.64 yr -1 , natural mortality rate (M) at 1.04 yr -1 , fishing mortality (F) at 4.60 yr -1 , and exploitation rate (E) at 0.82 yr -1 . Yield per recruit (expected lifetime yield per fish recruited in the stock at a specific age) analysis showed an excessive fishing effort. Using the analysis of probability of capture of each length class, the length at first capture (L c ) of H. brachysoma was estimated to be 110mm. An indication of both growth and recruitment fishing is provided by the dominance of year 1 class in the exploited population and the capture of immature individuals below first maturity. Management of H. brachysoma fishing should include setting of a minimum mesh size limit of 160-180 mm for gill nets as well as a closed season starting from the month of May till August aimed at protecting the spawning stock. This study on H. brachysoma, an endemic and threatened catfish of peninsular India, provides hard evidence that species targeted by artisanal fishermen, in small-scale tropical riverine fisheries, are vulnerable to overexploitation.

Objective:To assess the sanitary condition and water quality of household wells and to depict it spatially using Geographic Information System (GIS) in an urban area of Trivandrum, Kerala state, India.Study design:A community-based cross-sectional census-type study.Methods:Study was conducted in an urban area of Trivandrum. All households (n = 449) residing in a 1.05 km2 area were enrolled in the study. Structured questionnaire and Differential Global Positioning System (DGPS) device were used for data collection. Water samples taken were analyzed in an accredited laboratory.Results:Most of the wells were in an intermediate-high contamination risk state, with more than 77% of wells having a septic tank within 7.5 m radius. Coliform contamination was prevalent in 73% of wells, and the groundwater was predominantly acidic with a mean of 5.4, rendering it unfit for drinking. The well chlorination and cleaning practices were inadequate, which were significantly associated with coliform contamination apart from a closely located septic tank. However, water purification practices like boiling were practiced widely in the area.Conclusion:Despite the presence of wells with high risk of contamination and inadequate chlorination practices, the apparent rarity of Water-borne diseases in the area may be attributed to the widespread boiling and water purification practices at the consumption level by the households. GIS technology proves useful in picking environmental determinants like polluting sources near the well and to plan control activities.

The feeding strategy, overlap and trophic interactions of four demersal catfishes inhabiting Cochin Estuary, Arius maculatus (n = 67), A. subrostratus (n = 63), A. arius (n = 21) and Mystus gulio (n = 69) were investigated through gut‐content analyses. The indices of relative importance revealed that the prey items in their stomachs were dominated by crustaceans except in A. arius where molluscs constituted the major prey item. The highest diet and niche breadth values (3.93, 0.36 respectively) were recorded in A. subrostratus, while the lowest was recorded in A. arius (2.64, 0.23 respectively). Pianka's overlap, calculated through null models constructed by Ecosim 7.0, revealed significant niche overlap between A. maculatus and A. subrostratus (O–0.91, P < 0.001), between A. maculatus and M. gulio (O–0.72, P < 0.05) and between A. subrostratus and M.gulio (O–0.64 P < 0.05). However, no overlap was recorded between A. arius and other species. The trophic niche breadth along with prey specific abundance confirmed that these fishes are highly specific feeders. The present results on trophic level status indicate that these catfishes are mid‐level carnivores that can be considered as moderate benthic mesopredators and are specialist feeders unlike most catfishes.