Aquatic coleoptera and hemiptera taken at light in some Asian countries with a note on Sphaerodema (Hemiptera-Belostomatidae)

Aquatic insects are relatively common at artificial lights and are often taken in light traps operated for catching other insects. They are however seldom recorded. These records are however of importance in understanding their distribution and abundance. Aquatic Coleoptera and Hemiptera are of importance in fisheries because some of them are predators on small fish whilst others serve as food for fishes of all sizes. Some like the Corixidae are of special interest because they can utilize the bottom ooze which is abundant especially in small habitats. Fernando (1961a) gave a comprehensive bibliography of records at light. In the present paper a number of records are given from various parts of Asia, where in the past records were very few. They are based on collections made by the author and also on material in the Zoological Survey of India, Calcutta. Amongst specimens sent for study by the Bernice P. Bishop Museum, Honolulu, were a few specimens which had been recorded at light.

Optical learning in a smart spatial light modulator

A synaptic plane rendered by an array of smart pixels was described regarding its application as a complementary component for neural network implementation. The smart spatial light modulator featured auto-modification abilities. Thus, an optical system incorporating this device can show self-reliant optical learning. Furthermore, the optical system design, in the area of its optical interconnection scheme, is highly flexible since the independent weight-plane pixels eliminated the difficulty between weight update calculation and weight representation.

Influence of light on diurnal behaviour of Carangids in the Wadge Bank trawl fishery

Adequate data on the Wadge Bank fishery relating to several groups of fish, including Carangids, taken in bottom trawls are available for study. Analysis of this data indicated that the variation in Carangid catches was related to the time of day. In this paper, the available Wadge Bank fishery data is analysed and discussed to show the diurnal changes in Carangid catches and the probable influence of light in affecting these changes.

Centrifuge tests investigating inclined grout micro-piles as a method of liquefaction remediation for existing buildings

This paper presents a series of centrifuge tests carried out to investigate the performance of non-structural inclined micro-piles as a potential liquefaction remediation method for existing buildings. Both a single-degree-of-freedom frame structure and a two-storey, two-degree-of-freedom frame structure were used as model buildings in these tests. Centrifuge tests were carried out with and without micro-piles in the foundation soil for each structure. Results primarily from the tests with the SDOF structure are presented in this paper. It is found that the micro-piles have some beneficial effect by increasing shear strains in the soil in their vicinity and hence causing dilation in these zones. However, they also increase structural accelerations by transmitting accelerations from deep in the soil and the beneficial effects from increased dilation are outweighed by the detrimental migration of pore pressures.

Management of the nile perch, Lates niloticus, fishery in Lake Victoria in light of the changes in its life history characteristics

Nile perch, Lates niloticus Linnaeus, 1758, is a predatory fish of high commercial and recreational value. It can grow to a length of 2 m and a weight of 200 kg. In Uganda, Nile perch was originally found only in Lake Albert and the River Nile below Murchison Falls. The species is, however, widely distributed in Africa, occurring in the Nile system below Murchison Falls, the Congo, Niger, Volta, Senegal and in Lakes Chad and Turkana (Greenwood 1966).

Centrifuge modelling of inclined micro-piles for liquefaction remediation of existing buildings

This paper describes four centrifuge tests investigating the performance of non-structural inclined micro-piles as a liquefaction remediation method for existing buildings. Two soil profiles with the same superstructure founded on each were tested under earthquakes of different magnitudes and durations. The first profile consisted of a deep, homogeneous layer of loose, liquefiable sand. The second comprised a shallow layer of loose sand overlying dense sand. Centrifuge tests were carried out with and without inclined micro-piles in each soil profile. The superstructure was modelled as an idealised single degree of freedom (SDOF) system. It is found that the micro-piles have no detrimental effect on the performance of the structure during and after earthquakes. It is also possible that their presence may decrease structural settlements in earthquakes which cause liquefaction to a depth less than that of the improved zone. However, no conclusive evidence is obtained to show that the micro-piles significantly restrain lateral soil movement due to monotonic shearing from the structure or impede the migration of excess pore pressures from the free field to the foundation zone. Both these processes have critical effects on structural settlement. The use of inclined micro-piles for liquefaction remediation should therefore be considered with caution.

Cementation liquefaction remediation for existing buildings

Many typical liquefaction remediation techniques are not appropriate for application under existing buildings and more novel techniques are required. This paper describes centrifuge tests investigating the performance of cementation as a liquefaction remediation method. Two soil profiles with the same superstructure were tested under earthquake shaking. The first profile consisted of a deep layer of loose, liquefiable sand. The second comprised a shallow layer of loose sand overlying dense sand. Centrifuge tests were carried out with a cemented zone underneath the structure, through the full depth of the liquefiable layers and also partial depth. The superstructure was modelled as a single-degree-offreedom system. It is found that a cemented zone through the full depth of a liquefiable layer results in considerable reduction of structural settlements. Increased magnitude and higher frequency accelerations are transmitted to the structure but, depending on the building characteristics, it is likely that improved overall seismic performance can be achieved. Improvements in structural settlements can also be obtained with partialdepth remediation, if the depth of the cemented zone is greater than the depth of liquefaction. This type of remediation seems to have little effect on the accelerations transmitted to the structure.