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Search Results: 1 - 10 of 52 matches for " Roksana Huque "
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Comparative Studies on the Susceptibility of Various Vegetables to Bactrocera tau (Diptera:Tephritidae)
Roksana Huque
Pakistan Journal of Biological Sciences , 2006,
Abstract: To study on the susceptibility of various vegetables to the females of B. tau, six vegetables (sweet gourd, kankrol, cucumber, potol, bottle gourd, snake gourd) were chosen as hosts for comparable studies by using choice and non-choice test. In choice test six species of vegetables were placed in small pieces (300 g) simultaneously for laying eggs by the 50 pairs of flies for the period of 2 h. On the other hand in non-choice test 300 g of either vegetables species were placed as oviposition substrate to 50 pairs of flies. Female flies showed various responses to the vegetables with regards to oviposition and adult emergence. According to the number of eggs laying by the female flies kankrol was found most susceptible and bottle gourd was found less susceptible to B. tau.
Comparative Study of Raw and Boiled Silver Pomfret Fish from Coastal Area and Retail Market in Relation to Trace Metals and Proximate Composition
Roksana Huque,M. Kamruzzaman Munshi,Afifa Khatun,Mahfuza Islam,Afzal Hossain,Arzina Hossain,Shirin Akter,Jamiul Kabir,Yeasmin Nahar Jolly,Ashraful Islam
International Journal of Food Science , 2014, DOI: 10.1155/2014/826139
Abstract: Trace metals concentration and proximate composition of raw and boiled silver pomfret (Pampus argenteus) from coastal area and retail market were determined to gain the knowledge of the risk and benefits associated with indiscriminate consumption of marine fishes. The effects of cooking (boiling) on trace metal and proximate composition of silver pomfret fish were also investigated. Trace element results were determined by the Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometer wherein fish samples from both areas exceeded the standard limits set by FAO/WHO for manganese, lead, cadmiumm and chromium and boiling has no significant effects on these three metal concentrations. Long-term intake of these contaminated fish samples can pose a health risk to humans who consume them. 1. Introduction Fish is a healthy food for most of the world’s population particularly developing countries in contrast to meat, poultry, and eggs. Fish provides comparatively cheap and readily available protein sources (about 15 to 20 percent) in addition to long chains of n-3 fatty acids, amino acids, vitamins, and minerals which contributes to healthier nutritional options for a balance dietary intake [1, 2]. Among the all fishes, marine fish are very rich sources of protein and various mineral components. The total content of minerals in raw flesh of marine fish is in the range of 0.6–1.5% of wet weight [3]. Trace metals are present in water from natural sources such as the rocks of the sea bed and also accumulated as a result of human activities such as emissions from industrial processes. These elements are taken up by marine fishes which are higher up the food chain. As a result, the concentrations of many elements including mercury, arsenic, lead, and cadmium in fish can be relatively high compared to other foods. Many of these metals such as iron, copper, cobalt, manganese, molybdenum, nickel, and zinc are essential trace elements and play important roles in biological systems. Meanwhile, mercury, lead, and cadmium are toxic, even in trace amounts [4]. Moreover, elevated concentration of manganese and nickel has been found to be toxic to aquatic organism [5, 6]. To monitor trace metals concentrations in the coastal environment, marine fishes have been widely used as bioindicators due to their wide range of distribution. Several studies have been carried out on metal pollution in different species of edible fish. Predominantly, fish toxicological and environmental studies have prompted interest in the determination of toxic elements in seafood [7–10]. According to the
Prospect for Cell Phones as Instructional Tools in the EFL Classroom: A Case Study of Jahangirnagar University, Bangladesh
Roksana Begum
English Language Teaching , 2011, DOI: 10.5539/elt.v4n1p105
Abstract: Though mobile assisted language learning is an important issue in ELT in many countries, Bangladesh is far away from this method of learning. The present paper has focused on the mobile assisted language learning where the author has tried to explore the potential of cell phone usages as instructional tool in EFL classroom of Bangladesh. The researcher conducted a case study on Jahangirnagar University of Bangladesh. Some undergraduate EFL students participated in the study as subjects. To find out the benefits and challenges of using cell phones in the classroom, some SMS based class tests were conducted where the teachers sent mobile SMS to students as a means of instruction for teaching appropriate use of preposition and to find out the efficacy of SMS based class, a test was also taken via SMS and students also replied and students were given feedback through SMS. After that, students and teachers opinion regarding the cell phone usages; its benefits and inhibiting factors for the implementations in the EFL classroom are collected through students’ questionnaire, teacher interviews and classroom observation reports. The research results imply that cell phone has great potential as instructional tool despite some challenges that can be solved by the sincere attempts of the authority, teachers and by changing the ethical point of view that consider cell phones as mere a disturbing factor in the classroom. Some probable solutions for the challenges of using cell phone in the class are also presented. The study will be beneficial for educators of Bangladesh and many developing countries like Bangladesh. It will also be supportive for the EFL teachers and students who are always pursuing for more innovative way for teaching and learning English. Such studies are rare in Bangladesh, though some studies regarding m-learning are done by some researchers previously.
Influence of Reactive Volatile Organic Compounds on Ozone Production in Houston-Galveston-Brazoria Area  [PDF]
Samarita Sarker, Raghava R. Kommalapati, Ziaul Huque
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.64039
Abstract: Secondary pollutant ozone (O3) formation in a particular area is often influenced by various factors. Source of emissions is one of the factors. In south east Texas, Houston-Galveston-Brazoria (HGB) is a marginal non-attainment area for ozone (O3). A summer episode of May 28 to July 2, 2006 is simulated using Comprehensive Air Quality Model with extensions (CAMx). During this period O3 concentration in HGB often exceeds the National Ambient Air Quality Standards (NAAQS) 0.075 ppm of average 8 hour O3 concentration. HGB area has numerous point sources. Various studies found that some specific volatile organic compounds are very reactive in atmosphere. The objective of this study is to analyze the influence of volatile organic compounds present in point source emissions on the air quality of HGB area. For this purpose ozone sensitivity for HGB area is analyzed by the ratio of hydrogen peroxides (H2O2) to nitric acid (HNO3). HGB area is found NOx limited but reactive VOCs are found to be influential too. From (1-4 June, 2006) maximum O3 concentration was found on weekend, June 3. VOCs such as Acetaldehyde (ALD2), Formaldehyde (FORM) and Alkane (ETHA) showed good correlation with O3 concentrations on that day. In addition, Peroxyacetyl nitrate (PAN) formation was found correlated to higher ozone production. Criteria pollutant Sulfur dioxide (SO2) was found to influence the ALD2 and ETHA concentrations, and thus indirectly influenced O3 production.
Injury-related unsafe behavior among households from different socioeconomic strata in Pune city
Mirkazemi Roksana,Kar Anita
Indian Journal of Community Medicine , 2009,
Abstract: Introduction: Behavior pattern influences the risk of unintentional injuries. This study was conducted to identify the pattern of household unsafe behavior in different socioeconomic strata, in Pune city, India. Materials and Method: Population-based, cross-sectional study. Behaviors influencing the risk of burn, poisoning, drowning, and road traffic injuries were questioned from 200 randomly selected households. Results: Nearly 28% of the households did not have a separate kitchen, 37.5% cooked at the ground level, 33.5% used a kerosene pressure stove, 12% used unprotected open fire as a source of warmth in winter, and 34.5% stored inflammable substances at home. Ninety one percent of the households reported storing poisonous chemicals in places that could not be locked. In 68.3% of the households with children below five years, these chemicals were kept in places accessible to children. Nearly 21% of the individuals, who could swim, did so in unsafe places and 25.2% of them were not trained in swimming. In 35.5% of the households, children used streets as playgrounds. Among all two-wheeled vehicle riders, 35.6% reported not having a helmet and 57.7% of those who had a helmet did not use it regularly. Socioeconomic status was strongly associated with the unsafe behaviors related to burns, drowning, and road traffic injuries. Conclusion: The study identifies the sociocultural and behavioral factors leading to unsafe behaviors, placing individuals at risk of unintentional injuries, which can be used as a first step toward prevention.
Life-Cycle Analysis of Bio-Ethanol Fuel Emissions of Transportation Vehicles in Greater Houston Area  [PDF]
Raghava Kommalapati, Shahzeb Sheikh, Hongbo Du, Ziaul Huque
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.76072
Abstract:

Study is conducted on the life cycle assessment of bio-ethanol used for transportation vehicles and their emissions. The emissions that are analyzed include greenhouse gases, volatile organic compounds, sulfur oxide, carbon monoxide, nitrous oxide, particulate matter with the size less than 10 and 2.5 microns. Furthermore, various blends of bio-ethanol and gasoline are studied to learn about the impacts of higher blend on emissions. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model software are used to simulate for emissions. The research analyzes two pathways of emissions: Well-to-Pump and Pump-to-Vehicle analyses. It is found that the fuel cell vehicles using 100% bio-ethanol have shown the most reduction in the amount of all the pollutants from the Pump-to-Vehicle emission analysis. The Well-to-Pump analysis shows that only greenhouse gases (GHGs) reduce with higher blends of bio-ethanol. All other pollutants VOC, CO, NOx, SOx, PM10 and PM2.5 emissions increase with the higher blending ratios. The Pump-to-Vehicle analysis shows that all the pollutant emissions reduce with the percentage increase of bio-ethanol in the fuel blends.

Impact of Different Parameters on Life Cycle Analysis, Embodied Energy and Environmental Emissions for Wind Turbine System  [PDF]
Nazia Binte Munir, Ziaul Huque, Raghava R. Kommalapati
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.77089
Abstract:

Due to the rapid depletion of fossil fuel reserves and increasing concern for climate change as a result of greenhouse gas effect, every country is looking for ways to develop eco-friendly renewable energy sources. Wind energy has become a good option due to its comparative economic advantages and environment friendly aspects. But there is always an ongoing debate if wind energy is as green as it seems to appear. Wind turbines once installed do not produce any greenhouse gases during operation, but it can and may produce significant emissions during manufacture, transport, installation and disposal stages. To determine the exact amount of emissions, it is necessary to consider all the stages for a wind turbine from manufacture to disposal. Life Cycle Analysis (LCA) is a technique that determines the energy consumption, emission of greenhouse gases and other environmental impacts of a product or system throughout the life cycle stages. The various approaches that have been used in the literature for the LCA of wind turbines have many discrepancies among the results, the main reason(s) being different investigators used different parameters and boundary conditions, and thus comparisons are difficult. In this paper, the influence of different parameters such as turbine size, technology (geared or gearbox less), recycling, medium of transport, different locations, orientation of the blade (horizontal or vertical), blade material, positioning of wind turbine (land, coastal or offshore), etc. on greenhouse gas emissions and embodied energy is studied using the available data from exhaustive search of literature. This provides tools to find better solutions for power production in an environmental friendly manner by selecting a proper blade orientation technique, with suitable blade material, technology, recycling techniques and suitable location.

A Geometric Model to Reduce Interference Computations in Simulation of Large Ad hoc Networks
Roksana Akter,M. Lutfar Rahman
Journal of Networks , 2011, DOI: 10.4304/jnw.6.1.46-53
Abstract: Simulation of wireless networks has recently drawn considerable attention in the area of abstraction. Simulation is a precious tool used to model complex systems where the desired network size is large in scale. For large mobile ad hoc networks, the most computation intensive tasks in simulation are computing interference and determining which receivers are in range of a transmitter. In both cases, O(N2) physical layer calculations are required for a wireless system of N nodes, which scales poorly. In this paper, a geometric model, minimal rectangular coverage area is devised for the optimization of the complexity of interference computations in simulations of wireless mobile ad hoc networks. This method lessens the number of unaffected nodes by considering less area as affected by transmission range, which exists outside the transmission range of a transmitter. However, the experimental results suggest that this geometric model reduce the affected coverage area 12.5% - 78.15% than existing grid based algorithm used in current version of NS2. This paper also discusses about the efficiency considerations of the algorithm in detail.
Simulation Based Design Analysis of an Adjustable Window Function  [PDF]
Orvila Sarker, Rezaul Huque Khan
Journal of Signal and Information Processing (JSIP) , 2016, DOI: 10.4236/jsip.2016.74019
Abstract: Window based Finite Impulse Response filters have the problem that in order to obtain better performance from these filters in terms of minimum stopband attenuation cost has to be paid for half main-lobe width and vice-versa. A solution of this contradictory behavior is to increase the length of the window which in turn requires more hardware hence increasing the cost of system. This paper proposes a novel window based on two shifted hyperbolic tangent functions. The proposed window contains an adjustable parameter, with the help of which desired time and frequency domain characteristics may be achieved for relatively shorter window length. The characteristics of the proposed window are compared with those of the two well-known adjustable windows namely Cosh window and Exponential window. MATLAB simulation results show that for the same value of window length, the proposed window provides improved output, and thus it makes a good compromise between minimum stopband attenuation and half main-lobe width compared to the windows mentioned previously.
Non-equilibrium Green s function based model for dephasing in quantum transport
Roksana Golizadeh-Mojarad,Supriyo Datta
Physics , 2007, DOI: 10.1103/PhysRevB.75.081301
Abstract: The objective of this paper is to describe a simple phenomenological approach for including incoherent dephasing processes in quantum transport models. The presented illustrative numerical results show this model provides the flexibility of adjusting the degree of phase and momentum relaxation independently that is not currently available in mesoscopic physics and in device simulations while retaining the simplicity of other phenomenological models.
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