Effects of cowdung application on the production of mud crab (Scylla serrata Forskal) in brackishwater pond

A culture experiment of mud crab for 84 days was conducted in earthen pond at Brackishwater Station, Bangladesh Fisheries Research Institute, Paikgacha, Khulna. The aim of the experiment was to study the effects of cowdung application on crab production and water quality. There were three treatments as without cowdung (T1), 500 kg cowdung/ha/fortnight (T2) and 750 kg cowdung/ha/fortnight (T3) with three replicates for each. The result was evaluated on the basis of growth, production, survival rate etc. The experimental months were mid-April '96 to mid-July '96. To maintain a good water quality, water was exchanged in every spring tide. The range of salinity during the experiment was 8-19 ppt. Trash fish and fresh shrimp head were used as feed on raw basis in every alternate week at a rate of 8% body weight of crab at the same time rice bran and wheat flour were used at a rate of 2% body weight as a source of carbohydrate. The production of T1, T2 and T3, were 720.35 kg, 862.16 kg and 669.19 kg/ha respectively. Though the effects of cowdung on production of crab is insignificant but in terms of production, survival rate and growth, the study suggest that the application of cowdung in addition to feed can be recommended for mud crab culture at a rate of 500 kg/ha/fortnight

The asymmetric role of corporate governance in CEO pay determination: evidence from South Africa

© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. Previous studies suggest that CEOs may be incentivised to pursue actions aimed at restoring equity when pay deviates from the predicted CEO labour market compensation rate. This study investigates the effect of corporate governance (CG) quality on CEO pay deviation in an emerging economy characterised by weaker external corporate regulatory environment. Using a unique hand-collected data of 185 South African listed firms over a six-year period, We document that whereas CG quality impacts negatively on total CEO pay deviation, this is only conspicuous when the CEO is overpaid. CG quality has no effect on CEO compensation when the CEO is underpaid. We find that CEO underpayment reduces firm value in poorly-governed firms. In contrast, CEO overpayment has no effect on firm value irrespective of the level of CG quality. The findings imply that recent CEO pay level agitations have resulted in the design of CG mechanisms that reduces the tendency of CEO pay to adjust upwards. The results are robust to alternative econometric techniques and endogeneity concerns

Water quality management on the enhancement of shrimp (Penaeus monodon Fab.) production in the traditional and improved-traditional ghers of Bangladesh

On-farm research on enhancement of P. monodon production through water quality management was carried out in five ghers of Paikgacha, Khulna. Based on the prevailing condition of the ghers, lime in the form of CaCO(sub 3), urea and TSP were used as the major inputs to minimize the soil-water acidity and to ensure the availability of natural food particles in the water bodies. Exchange of water at required level also practiced for the qualitative improvement of culture water. Ghers of varying sizes showed that water quality management and fertilization have a positive impact on production performance of P. monodon (61.59% increment) that yielded an average production of 385.43 kg/ha/crop against the present traditional rate of 238.50 kg/ha/year

Disease problems in shrimp sector in Khulna district of Bangladesh: a question of sustainability

Disease is the main restraining factor for the development of shrimp sector in Bangladesh. Both brackish water shrimp bagda (Penaeus monodon) and freshwater prawn golda, (Macrobrachium rosenbergii) farming in Bangladesh have been facing disease problem. A study on disease outbreak in both brackish water and freshwater small-scale shrimp farms (gher) in Khulna district was carried out through interviewing randomly selected 3-5% of shrimp farmers with a structured questionnaire during March to December, 2002. The study showed that 97% bagda farming ghers and 80% golda farming ghers were affected by disease. White spot disease was the severe disease for bagda, whereas, antenna rot was the main disease for freshwater prawn. Change of water and liming were carried out as control measures of disease for bagda shrimp farming, while it was only liming for golda farming. A small number of shrimp farmers (15%) used chemicals for treatment of shrimp diseases. Development of suitable farming technology to prevent disease contamination and innovation of proper treatments for diseases are required to overcome the disease problems for sustainable shrimp farming in Bangladesh

Coherent transport in linear arrays of quantum dots: the effects of period doubling and of quasi-periodicity

We evaluate the phase-coherent transport of electrons along linear structures of varying length, which are made from two types of potential wells set in either a periodic or a Fibonacci quasi-periodic sequence. The array is described by a tight-binding Hamiltonian and is reduced to an effective dimer by means of a decimation-renormalization method, extended to allow for connection to external metallic leads, and the transmission coefficient is evaluated in a T-matrix scattering approach. Parallel behaviors are found for the energy dependence of the density of electron states and of the transmittivity of the array. In particular, we explicitly show that on increasing its length the periodic array undergoes a metal-insulator transition near single occupancy per dot, whereas prominent pseudo-gaps emerge away from the band center in the Fibonacci-ordered array.Comment: 11 pages, 7 figure

Machine learning for intrusion detection in industrial control systems : challenges and lessons from experimental evaluation

Abstract: Gradual increase in the number of successful attacks against Industrial Control Systems (ICS) has led to an urgent need to create defense mechanisms for accurate and timely detection of the resulting process anomalies. Towards this end, a class of anomaly detectors, created using data-centric approaches, are gaining attention. Using machine learning algorithms such approaches can automatically learn the process dynamics and control strategies deployed in an ICS. The use of these approaches leads to relatively easier and faster creation of anomaly detectors compared to the use of design-centric approaches that are based on plant physics and design. Despite the advantages, there exist significant challenges and implementation issues in the creation and deployment of detectors generated using machine learning for city-scale plants. In this work, we enumerate and discuss such challenges. Also presented is a series of lessons learned in our attempt to meet these challenges in an operational plant

Ethnic Association in Primary Systemic Vasculitis: A Systematic Review

Background: Literature described wide disparities in incidence and prevalence between different types of vasculitis. There were no comprehensive studies on ethnic or racial associations in all types of primary systemic vasculitis (PSV) in any published article, until this review commenced in 2020. The purpose of the review is to synthesize the evidence regarding the relation of ethnicity and the incidence and/or prevalence of different types of PSV. Methods: A total of 52 selected articles which include Clinical trials, cohorts, cross-sectional studies, case series, and case studies and have been published within the last 10 years in the human population, were reviewed by searching The Medline, PubMed, and Google Scholars databases using predefined keywords. The PRISMA diagrams were followed to identify relevant articles. The methodological qualities of the studies were assessed using the EPHPP tool. Finally, a summary of the evidence on the association between ethnic origin and PSV was painstakingly compiled. Results: The connection between ethnicity and different types of PSV has been found to be significantly diverse in this research such as vasculitis is more common in Asians and Scandinavians, Kawasaki disease and periarteritis nodules are more prevalent in Japanese and Alaska-natives, ANCA-associated vasculitis is more frequent in Caucasians, whereas Henoch-Schonlein purpura and Cogan syndrome more usual in Caucasians and Asians. Furthermore, Behçet's disease more commonly occurs on the "Silk Road", especially in Turkey. Conclusion: Genetic susceptibility and environmental elements could be the contributing factors to the global variation in the incidence and prevalence of primary systemic vasculitis