Cultivation and uses of stevia (Stevia rebaudiana Bertoni): a review

Stevia [Stevia rebaudiana Bertoni; Family Asteraceae] is a natural sweetener plant that is grown commercially in many parts of Brazil, Paraguay, Central America, Thailand, Korea, China and India. The leaves of stevia are the source of sweet glycosides. It is mainly used as a sweetener and flavor enhancer in the food and beverage industry. The chemical compound obtained from stevia is considered to be the best alternative source of sugar especially for diabetes patients. Climatic factors and agronomical practices affect the quality and quantity of yield. The concentration of stevioside in the leaves is higher when the stevia plants are grown under long days and when these plants are harvested just prior to flowering. Time of harvesting depends on land type, type of stevia and growing season. The first harvest can be done four months after planting and subsequent harvest once after every 3 months. Such medicinal plants are becoming fairly popular for the treatment of different diseases all over the world. It could be suitable for diabetic and obese persons. It also showed antibacterial, antiseptic, anti-inflammatory, anti-fertility, hypotensive, diuretic and cardiotonic properties. Stevia is a small perennial shrub that has been used for centuries as a bio-sweetener and for other medicinal purposes. In addition, alternative sweeteners offer another benefit in maintaining good dental health. S. rebaudiana sweeteners are used sparingly and there seems to be no threat to public health. Stevia has been introduced to the Kenyan market as one of the cash crops for agro-based industry. The changes in leaf yield and accumulation of stevioside in response to different environmental conditions and nutritional variations might provide some leads to develop strategies for increasing the productivity of the stevia. Quality of the stevia product depends on drying temperature; high temperatures negatively affect quality, diminishing medicinal and commercial value. Multiple global regulatory organizations have determined that consumption of high quality stevia products within recommended doses is safe for all.Keywords: Stevia, Cultivation, Medicinal uses, Diabetes, Natural sweetener, Flavor enhancer, Glycoside

Organoleptic, biochemical and bacteriological aspects of the low cost tunnel dried fish products

Studies were conducted on the organoleptic, biochemical and bacteriological aspects of three dried fish products produced from two different model of low cost solar tunnel dryer. The overall quality of the products obtained from both dryers was excellent. Sixty minutes soaking showed the maximum water reconstitution of the products with values between 66.82 to 75.28% and 71.98 to 78.09% in dryer 1 & 2 respectively. The highest reconstitution was obtained from Silver Jew fish (75.28-78.09%) and lowest from Bombay duck (66.86-71.98%) from both dryers. The average moisture, protein, lipid and ash content of the dried products were 11.8-15.0%, 57.32-68.49%, 6.08-8.62% and 12.25-14.88% respectively in fish in dryer 1 and dryer 2. The TVB-N values were in the range of 24.3 to 30.9 in dryer 1 and 22.1 to 28.2 mg/100 g samples in dryer 2. The highest values were obtained from Bombay duck and lowest value in Silver Jew fish in both dryers. The peroxide values varied from 14.1 to 16.9% in dryer 1 and 13.3 to 16.4% in dryer 2. The highest peroxide value was obtained from Ribbon fish and lowest from Silver Jew fish. Total bacterial load varied in the range of 6.6x10⁴— 8.6x10⁴ CFU/g in dryer 1 and 2.54x10⁴ to 4.9x10⁴ CFU/g in dryer 2. The highest value was obtained from Ribbon fish and lowest from Silver Jew fish

Identifying attributes of CO2 leakage zones in shallow aquifers using a parametric level set method

Bureau of Economic Geolog

Optimization of dose of methyltestosterone (MT) hormone for sex reversal in tilapia (Oreochromis niloticus L.)

This paper describes the optimization of dose of methyltestosteronei (MT) hormone for masculinization of tilapia (Oreochromis niloticus). Five treatments (i.e. T1 T2, T2, T4 and T5) with different doses such as 0, 40, 50, 60 and 65 mg of MT hormone were mixed with per kg of feed for each treatment and fed the fry four times a day up to satiation for a period of 30 days. The stocking density was maintained 10 spawn/liter of water. The growth of fry at different treatments was recorded weekly and mortality was recorded daily. At the end of hormone feeding the fry were reared in hapas fixed in ponds for another 70 days and at the 100th day the fish were sexed by the gonad squashing and aceto-carmine staining method. The analysis of growth data did not show any significant variation in length and weight of fish among the different treatments. High mortality of fry ranging 66% to 81.6% was observed in different treatments and highest mortality was observed during the first twelve days of the experiment. The sex ratio analysis showed that T2 (40 mg/kg) and T5 (65 mg/kg) produced 93.33% of sex reversed male and T3 (50 mg/kg) and T4 (60 mg/kg) produced 96.66% sex reversed male, and these ratios were significantly (p<0.05) different from 1:1 male: female sex ratio. The control, T1 (0 mg/kg) contained 43.33% male progeny. From these results it is suggested that either 50 mg/kg or 60 mg/kg of MT with a feeding period of 30 days could be considered as an optimum dose for masculinization of tilapia (O. niloticus)

Feasibility of double-layer microchannel fabrication at low speed micro end-mill and wire-cut EDM machines

This study compares micron-scale features of double layer-microchannel heat sink (DLMC) fabrication.Massive theoretical researches investigated DL-MC and its advantages over single-layer. However, micro-machining of DL-MC is still immature area. Here, Two advanced machining technologies, namely: Micro end-mill and wire-cut EDM are utilized to fabricate a DL-MC. Investigation on burr formation, surface roughness and shape configuration that influence heat transfer mechanism is done through a series of machining runs. Manipulating machine parameters such as: spindle speed, feed rate and tool dimension shown that low speed micro end-mill is capable of creating sufficient DL-MC quality. Also, scanning electron microscope (SEM) micrographs and roughness measurement reveal that wire-cutEDM is better in machining time and stability of surface roughness

Culture feasibility of african catfish (Clarias gariepinus Lin.) fry in glass tank and synthetic hapa system using supplemental diets

An experiment was carried out with 1 0 days old Clarias gariepinus fry over a period of 42 days to determine the effects of different feeds on growth and survival of African catfish fry in glass tanks. The experiment was designed into four treatments each having three replications. Thus treatment 1 (T1) was named as Tank Tubifex (TT) and treatment 2 (T2) as Tank Sabinco (TS), treatment 3 as Pond Tubifex (PT), and treatment 4 (T4) as Pond Sabinco (PS). Live Tubifex (protein levels 64.48%) was supplied to treatments 1 and 3 and rest of the treatments were supplied Sabinco starter-1 (protein levels 40.13%). The highest and the lowest growth in total length and weight were 12.90cm, 18.77g and 6.17cm, 4.04g recorded from the treatments 3 and 2, respectively. Growth of catfish fry under treatment 3 in terms of both length and weight were significantly higher (P<0.01) than those of the other treatments. However treatment 2 showed the significantly lowest (P<0.01) growth performance among the various treatments. The highest survival rate (92%) was also obtained with treatment 3. Tubifex proved to be the best larval feed in respect of growth and survival rate

Geomorphological and land use mapping: a case study of Ishwardi under Pabna District, Bangladesh

The study presents geomorphological and land use mapping of the north western part of Ishwardi Upazila under Pabna district, Bangladesh. The objective of the research was to identify geomorphologicalunits and to prepare geomorphological and land use mapping based on remote sensing data and extensive field work. The satellite images of SPOT (Band 4) and Landsat TM-2012 were used for interpretation of geomorphological units. Land use elements are mapped using SPOT satellite images (Band 4) incorporated with field observation data.The study area consists of active channels, abandon channels, natural levees, flood plains, flood basins and lateral channel bars. The results revealed the need for regional and local land use policy revision employing a multi-disciplinary approach for sustainable development. The study advocates for the integration of geological factor in initial for land use planning in order to avoid damage of property and loss of lives. However, the study calls for further research work using different and longer data sets

The Effects of Air Flow in the Wake of a Large Vehicle on Trailing a Passenger Car

Road driving condition under drafting is known to have an influence on the aerodynamic forces of the vehicle. Large vehicles such as busses and trucks traveling at high speeds give results in the formation of a large turbulent flow in the wake region. This turbulent flow is very unsteady in nature hence its influence on the air flow within its vicinity will also be unsteady. This paper investigates the relative values of drag and lift forces acting on a passenger car trailing a large vehicle (drafting) under unsteady conditions. The simulation is conducted using Computational Fluid Dynamics software, FLUENT for a two-dimensional flow domain at Re 3.18x106 for a trailing distance of 0 to 30 meters. The unsteady effect is studied at 15 time intervals for each time step. Turbulence is simulated using the Reynolds-Average Navier Stokes (RANS) k-ε model. Results show that aerodynamically, the critical drafting distance is between three to five meters where the lowest drag is found to occur at three meters. The results show the suitable distance for drafting which may serve as useful information for vehicle fuel economy and stability

Aquaculture for income and nutrition: Final report

The United States Agency for International Development-Aquaculture for Income and Nutrition (USAID-AIN) project, implemented by WorldFish, emphasized technology development for improved fish strains, and capacity building in hatcheries and nurseries for wider dissemination and uptake among small- and medium-scale household and commercial producers. Improving nutritional benefits from household aquaculture investment was also an important activity of the project. Specifically, AIN aimed to increase aquaculture production by developing hatcheries and nurseries, disseminating improved fish and shrimp seed, enhancing farm management skills of smallholder farmers, promoting new technologies to expand commercial aquaculture, developing backward and forward market linkages, supporting policy reform and building capacity of the public and private sectors, which resulted in increased productivity and revenue for farmers. This report also highlights the major achievements of the AIN project between 2011 and 2016

Contributions of agroforestry on socioeconomic conditions of farmers in Central Punjab, Pakistan – a case study

Agroforerstry (AF) in the farmlands of Punjab (Pakistan) is a tradition, but it was practiced without any proper methodology. From last few years, AF practices have become popular in Punjab. Especially in the rural areas woody biomass is being used as a major source of energy. The study was designed to examine the contributions of AF on the socioeconomic conditions of the farmers in the central Punjab of Pakistan. District Chiniot was selected as the universe of study and a detailed survey was conducted in the three tehsiles by interviewing 150 randomly selected farmers with the use of a wellstructured questionnaire. In addition, secondary data was also collected from district agriculture offices. Chi-Square test was used for quantitative data analysis. Results showed that farmer’s annual income and household status was improved after practicing AF. Reasonably less poor farmers have more income increase than the poor farmers due to an extra investment, but income generation helped poor farmers to maintain the minimal living standards. Farmers perceived the advantage of trees immensely and the large scale farmers taking this as a genuine source of income. In adoption of AF, attitude of the farmers was independent of family size and settlement period, but was dependent on the occupation and number of livestock holding. The study suggested that, in the present financial scenario of the poor farmers, planting of suitable tree species with multiple benefits is an escape way to come out of the vicious circle of poverty. Along with that agroforestry can play a vital role in increasing the vegetation cover in forest deficient countries. Extension services and awareness programs should be arranged in the areas where people have negative attitude about AF practices, because the cultivated fields are the best places to grow the tree with crops. Moreover, subsidies and income generating project should be launched to motivate people towards AF