How is somatosensory information used to adapt to changes in the mechanical environment?

Recent studies examining adaptation to unexpected changes in the mechanical environment highlight the use of position error in the adaptation process. However, force information is also available. In this chapter, we examine adaptation processes in three separate studies where the mechanical environment was changed intermittently. We compare the expected consequences of using position error and force information in the changes to motor commands following a change in the mechanical environment. In general, our results support the use of position error over force information and are consistent with current computational models of motor learning. However, in situations where the change in the mechanical environment eliminates position error the central nervous system does not necessarily respond as would be predicted by these models. We suggest that it is necessary to take into account the statistics of prior experience to account for our observations. Another deficiency in these models is the absence of a mechanism for modulating limb mechanical impedance during adaptation. We propose a relatively simple computational model based on reflex responses to perturbations which is capable of accounting for iterative changes in temporal patterns of muscle co-activation.

A preliminary study on the protein requirement of Chanos chanos (Forskal) fry in a controlled environment

Growth rate of fish appeared to be related to the levels of the protein in the diet up to 40%. Fish fed diets containing 50 and 60% grew slower than those fed 40%, and the optimum level appears to be 40% when fed to fry at a rate of 10% of body weight. Best feed conversion of 1.96 was also obtained from the 40% protein diet. Mean survival rates were low in all treatments, but highest for the 40% protein diet. The competition of 5 isocaloric experimental diets containing various levels of protein are tabulated, as are weight gains, diet conversions and survival rates for milkfish fry fed various dietary levels of protein. Growth curves for milkfish fry are shown, and the relationship between weight gains of milkfish fry and the dietary levels of protein are illustrated.

Fisheries, marine environment, and integrated coastal management policy processes, content and implementation in the BOBLME countries: regional synthesis and country questionnaires

This paper examines policy processes, policy trends and policy implementation with regards to capture fisheries, the marine environment and Integrated Coastal Management (ICM) in BOBLME countries. Individual country information was analyzed to generate a regional synthesis.

Shrimp culture and the environment

The paper discusses the impacts of shrimp culture to the environment in some countries in Asia. Specifically, it highlights the land requirements suitable for shrimp farming and the impacts of shrimp culture on mangroves. The positive effects of mangroves such as its filtering capacity and as a protective buffer are also discussed.

Assessment of pelagic primary and secondary production in Sefidrud River estuary

Sefid-Rood River Estuary (SRE) is the most important riverine ecosystem in the south Caspian Sea along the Iranian coast lines. The aim of this study was to examine spatial and temporal variability in Phytoplankton and Zooplankton abundance and diversity in SRE. Variability of Chlorophyll a and inorganic nutrient concentration were determined during a year (November 2004– October 2005) in five sampling stations. Primary and secondry production were determined during a year. Total chlorophyll a concentration during the investigation ranged between zero to 22.8 μgl-1 and the highest levels were consistently recorded during summer and the lowest during winter with a annual mean concentration 4.48 μgl-1. Nutrient concentration was seasonally related to river flow with annual mean concentration: NO2 0.05±0.2 mgl-1, NO3 1.13±0.57 mgl-1, NH4 0.51±0.66 mgl-1, total phosphate 0.13±0.1mgl-1 and SiO2 5.68±1.91 mgl-1. Bacillariophytes, Cyanophytes, Chlorophytes, Pyrophytes and Euglenophytes were the dominant phytoplankton groups in this shallow and turbid estuary. The diversity and abundance of phytoplankton had a seasonal pattern while Diatomas and Chrysophytes were dominant throughout the year but Cyanophytes observed only during the summer. Zooplankton community structure was dominated by copepods which 68% of the total zooplankton. In the winter and summer seasons two increased in the number of zooplankton community and usually toward the sea had occurred. Zooplankton also showed a significant spatial and temporal variation. The high turbidity and temperature prime characteristics of SRE seem to be determining factors acting directly on phytoplankton and zooplankton temporal variability and nutrient fluctuations. Everywhere in this estuary nutrients appeared to be in excess of algal requirement and did not influence a phytoplankton and zooplankton composition. Also there was a positive correlation between chlorophyll a and temperature and a negative one with DIN and TP. Primary production determined in this estuary by dark and light butter method and G.P.P. 38.27±34.12 mgcm-2h-1 and N,PP 201.6±289.9 mgcm-2d-1. secondry production determined 15/128 mgc/m3/year. Everywhere in this estuary nutrients appeared to be in excess to algal requirement and did not influence in Chl. a and primary production. The most important factor influence on Chl. a was water temperature.

Go for environment friendly aquaculture

The article presents environment friendly aquaculture practices such as semi-intensive aquaculture, the culture of native species, the selection of proper sites for aquaculture facilities, the conduct of thorough, honest socioeconomic and ecological impact assessment before proceeding with the implementation, and the practice and promotion of proper pond/cage/tank preparation and management among others.