Occurrence of Penta-Aromatic Hydrocarbons in Jaintia and Barail Group Mudstones, Northeastern Bengal Basin, Bangladesh

In the present experiment, concentration, distribution and sources of penta-aromatic hydrocarbons in seven drill core and outcrop samples from Jaintia and Barail Group mudstones, northeastern Bengal Basin, Bangladesh have been studied. Gas chromatography-mass spectrometry (GC-MS) was used to obtain composition details about the sedimentary organic matter (OM). Mudstone samples were found to contain relatively high penta-aromatic hydrocarbon abundances in the lower Jaintia Group than in the overlying Barail Group. High concentration of perylene suggests terrigenous sources and significantly higher content of total organic carbon in the samples. A biogenic origin of perylene therefore indicates oxygen deficient environmental condition for deposition of OM. Perylene over pentacyclic aromatic hydrocarbon isomers regulating in-situ diagenetic origin. DOI: http://dx.doi.org/10.3329/jles.v8i0.20154 J. Life Earth Sci., Vol. 8: 105-112, 2013

Vulnerability Concepts and its Application in Various Fields: A Review on Geographical Perspective

Vulnerability has no universal definition. Experts from various disciplines use the concept and define vulnerability, which leads diverse measuring methods to serve their own purpose and interests. Approaches to define vulnerability vary among the disciplines because of the various components of risk, household response and welfare outcomes. The objective of this paper is to present an overview based on available scientific literature from various disciplines to examine the origin, evolution and use of the vulnerability concept across different field of studies. Vulnerability is exclusively used in various disciplines such as geography, anthropology, economics, ecology, public health, poverty and development, sustainable livelihoods, famine and food security, sustainability science, land management, disaster management and climate change. Therefore, different disciplines have their own reasons for defining, measuring and developing conceptual models of vulnerability; hence there is no reason to presume that concepts, measures and methods will be universal across the disciplines. Lessons learned from one area may not be equally suitable for all. Hence, differences between various fields need to be bridged by a holistic approach and multidisciplinary research cooperation, and geography as a unique multidisciplinary field of study has the major disciplinary legitimacy to fill up the gaps and to create a common platform to work together in vulnerability research among the various research traditions. DOI: http://dx.doi.org/10.3329/jles.v8i0.20150 J. Life Earth Sci., Vol. 8: 63-81, 2013

Evaluation of the Antioxidant Activity of Ficus Racemosa Plant Extracts From North-Western District of Bangladesh

Antioxidant is a new hype in naturopathy and at present it has huge demand in cosmetic, nutritional supplementation and pharmacological industry. It reduces cell damages caused by free-radical which are responsible for various ailment like ageing, cancer, coronary heart disease, diabetes mellitus, neurodegenerative disorders, atherosclerosis, cataracts and inflammation. At present any comprehensive data on the antioxidant content and extent of their activity of the indigenous medicinal plants of Bangladesh is not available. Therefore, here antioxidant activity of a popular medicinal plant - Ficus racemosa was determined. Methanolic extract was prepared from the leaf and stem bark of F. racemosa. Their total phenolics and free radical scavenging capacity was determined using folin-ciocalteu reagent (FCR) assay and DPPD-radical scavenging assay respectively. Stem bark and leaves of F. racemosa contains 242.97 and 235.45 mg of GAE / gm of dried extract of phenolics respectively. Current studies also show that F. racemosa barks contain a high antioxidant activity. IC50 value of bark extract was found to be 19?g/ml which is even better that of the standard BHT. Therefore, present studies suggest that F. racemosa bark has a huge potential in terms of commercial use as source of antioxidant. DOI: http://dx.doi.org/10.3329/jles.v8i0.20152 J. Life Earth Sci., Vol. 8: 93-99, 2013

Stable Carbon and Oxygen Isotopic Composition of Mio-Pliocene Bivalve Shells and Calcareous Sediments in Nhila Anticline, Southeast Bengal Basin, Bangladesh

Stable carbon (?13C) and oxygen (?18O) isotopes of bivalve shells and calcareous sediments of the Mio-Pliocene Nhila Anticline, southeast Bengal Basin, Bangladesh have been investigated to obtain information on paleoclimate and paleoenvironment conditions during deposition. The ?13CPDB, ?18OPDB and ?18OSMOW values in bivalve shell range from -2.81‰ to -1.56‰, -3.57‰ to -2.39‰ and 27.18‰ to 28.40‰ in bivalve shells and -13.90‰ to -1.75‰, -4.71‰ to -2.13‰ and 26.01‰ to 28.66‰ in calcareous sediments, respectively. The ?13CPDB values in bivalve shells are comparable to that of calcareous sediments (~ -1.75‰) in the upper section, but ?13CPDB values in calcareous sediments are more negative excursion towards lower section (up to -13.90‰). These results signify that salinity gradients could modified the isotope values and/or strong influence of freshwater conditions. The variable ?18OPDB values in both bivalve shell and calcareous sediment suggesting diagenetic alteration of carbonates and water temperature effects. The more negative ?18OPDB values imply humid paleoclimatic conditions during the Mio-Pliocene sedimentation. Therefore, the ?18OPDB values of the Mio-Pliocene sediments of Nhila Anticline are probably controlled by paleotemperature leading to intensification of high rainfall. DOI: http://dx.doi.org/10.3329/jles.v8i0.20155 J. Life Earth Sci., Vol. 8: 113-117, 2013

Evaluation of Biological Activities of Evolvulus Nummularius L. through Insecticidal, Insect Repellency and Brine Shrimp Lethality Tests

Assessment of Evolvulus nummularius L. through whole plant extracts (collected in petroleum ether [Pet.E.], chloroform [CHCl3] and methanol [MeOH]) were made against Tribolium castaneum (Hbst.) for insecticidal and insect repellency and against Artemia salina L. for brine shrimp lethality, and the results were promising. The LC50 values against T. castaneum adults for Pet.E. extract were 1.280, 1.220, 1.096 and 1.030?g cm-2; for CHCl3 extract 3.249, 2.990, 2.526 and 2.204?g cm-2; and for MeOH extract 2.925, 1.899, 1.875 and 1.789?g cm-2, respectively for 12, 24, 36 and 48h of exposure. The intensity of activity could be arranged in a descending order: Pet.E. extract> MeOH extract> CHCl3 extract. For repellency, CHCl3 and MeOH extracts offered moderate activity (P <0.01), but the Pet.E. extract did not show efficacy against the beetles. The same extracts responded positively in brine shrimp lethality assay where the LC50 values for Pet.E. extract were 141.553, 98.941, 24.684 and 8.560ppm; for CHCl3 extracts 699.048, 366.663, 326.0039 and 40.114ppm; and for MeOH extracts 2336.982, 1258.605, 355.962 and 137.0589ppm respectively for 12, 18, 24 and 30h of exposure. However, the intensity of activity could be arranged in a descending order: Pet.E. extract> CHCl3 extract> MeOH extract. DOI: http://dx.doi.org/10.3329/jles.v8i0.20153 J. Life Earth Sci., Vol. 8: 101-104, 2013

Effect of Ethyl Methane Sulfonate (Ems) on Incubation Period, Pupal Period and Reproductive Potential of Ladybird Beetle, Epilachna Vigintioctopunctata Fab

DOI: http://dx.doi.org/10.3329/jles.v8i0.20156 J. Life Earth Sci., Vol. 8: 119-122, 2013

Climate Change and Land Use Change in the Eastern Coastal Belt of Bangladesh, Elucidated by Analyzing Rice Production Area in the Past and Future

Climate change is an important issue now-a-days. Global warming i.e. climate change causes sea level rise and that affect the coastal agricultural areas of Bangladesh. The net-cropped area of eastern coastal zone in Bangladesh has been decreasing over the years due to various purposes and the most common one is the land inundation and salinity intrusion by tidal water. The main aims of the study is to assess the change in climatic conditions particularly temperature, rainfall and agricultural land use change in the past and future. Past rainfall, temperature and salinity data have been used to assess the climatic and salinity conditions of the area under investigation. Normalized difference vegetation Index (NDVI) and False Color Composite (FCC) of digital Land sat images have been used to identify land use pattern and Boro rice coverage area. During last 31 years (1978 -2009) 31% rice production land has converted to shrimp culture and salt farming. Salinity intrusion is one of the major causes of agricultural land use change. Salinity level has increased dramatically in dry season during last decade due to increase of temperature, low rainfall pattern, high evaporation rate and low water discharge to the river systems. Future landuse has been projected for 2039 by Markov Model. Result shows that rice production area will decrease rapidly due to salinity intrusion as well as climate change which may threat for food security of Bangladesh. Hereafter, the Government of Bangladesh, national and international institutions will have to work together for minimizing the effect of climate change for food security. DOI: http://dx.doi.org/10.3329/jles.v8i0.20151 J. Life Earth Sci., Vol. 8: 83-91, 2013

Productivity, Cost-Benefit Analyses, Market Prices and Constraints to Poultry Farming in the Northern Districts of Bangladesh

A total of 6,41,004 chickens were produced by 10 farms, of which Cobb 500 (broilers) in P1 were the highest in number (2,43,000) and G1 yielded the lowest (10,117 Fayoumi, RIR and Sonali breeds). The most common chicken breed reared in the area was Cobb 500 (2,76,350) and the least common was ISA Brown (43,163). With regard to productivity, significant differences existed among the farms (F9, 103= 29.32; P<0.001), among the chicken breeds (F4, 108= 3.03; P<0.05), as well as between the government and private farms (F1, 111= 6.17; P<0.05). It was interesting to note that all the government farms were losing concerns (G2 > G3 = G4 > G1), while all the private farms were making profits (P1 > P3 > P2 > P6 > P4 = P5). The overall profitability index (PI) values of government farms ranged between -0.09 and -0.13, whereas those of private farms between 0.18 and 0.52. Cobb 500 was the commonest but the least profitable breed, and Sonali was the most popular and cheapest one; and the growers achieved the maximum profit from Fayoumi. High feed cost, outbreak of diseases, inadequate supply of vaccines/medicines, lack of credit facilities and capital funding were recognized to be the major constraints to the poultry farming in the study area. DOI: http://dx.doi.org/10.3329/jles.v7i0.20117 J. Life Earth Sci., Vol. 7: 21-27, 2012

Agricultural Land Conversion in the Sub-Urban Area: A Case Study of Rajshahi Metropolitan City

Bangladesh is a land scarce country where per capita cultivated land is only 12.5 decimals. It is claimed that every year about one percent of farm land in the country is being converted to non-agricultural uses. The study is based mainly on field survey covering 2 villages (Narikel Baria and Baze Silinda) from 10 sub-urban villages around Rajshahi City Corporation under Paba Upazila of Rajshahi district. The study area was selected purposively and the respondents of this research work were selected randomly. The major focus was on to mention the general land use pattern of the area, estimates the agricultural land conversion besides determining the causes and consequences affecting such conversion. Both Narikel Baria and Baze Silinda villages were selected as study area because of its relatively higher growth in infrastructure. In order to fulfill the goal of this study, primary and secondary data were collected from various sources and to analyze and process of collected data the SPSS, Excel and Arc GIS software were used. Different types of descriptive statistics were applied for representing the analyzed data. It is observed that the land conversion form agriculture to non-agriculture allied in recent time is more than the previous time due to gradually increasing land demand in housing and relevant services which invites adverse impact on agricultural land as well as its dependent population. So, it is necessary to take integrated land-use planning to offer better options for the fulfillment of land demand both of housing and agricultural sectors. DOI: http://dx.doi.org/10.3329/jles.v8i0.20136 J. Life Earth Sci., Vol. 8: 21-30, 2013

Climate Change Induced Flood Risk and Adaptation in the Padma River Island, Bangladesh: A Local Scale Approach

Assessment of hazard characteristics, exposure, vulnerability, resilience and risk at a local scale is an important tool for identifying the capacities of households and local communities to adapt with climate change induced flood. Repeated floods with different magnitudes under variable climatic conditions are great catastrophe for the people living in flood prone regions specifically in Islands. People, infrastructure and economy are highly exposed to flood and that results in devastating flood disaster. In the Padma river Islands frequent flooding makes the life and livelihoods of people vulnerable and this vulnerability is conditioned by different factors such as people’s physical, social, economic and environmental condition. The higher is the level of vulnerability the higher is the level of flood risk. Hence, people’s resilience can minimize the negative impacts of flood disaster. A composite risk index (related to the probability of occurrence of the event, magnitude of the event, quantity and cost of the element at risk, vulnerability and resilience) was prepared to realize the climate change induced flood disaster risk. Some adaptive strategies are explored to adapt with climate change induced flood risk. Finally, Local Scale Disaster Risk Model (LSDR) was proposed to present the framework of climate change induced flood disaster risk and adaption at a local scale. DOI: http://dx.doi.org/10.3329/jles.v8i0.20138 J. Life Earth Sci., Vol. 8: 41-48, 2013