Search results for: Organic farming
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2976

Search results for: Organic farming

936 Seasonal and Monthly Field Soil Respiration Rate and Litter Fall Amounts of Kasuga-Yama Hill Primeval Forest

Authors: Ayuko Itsuki, Sachiyo Aburatani

Abstract:

The seasonal (January, April, July and October) and monthly soil respiration rate and the monthly litter fall amounts were examined in the laurel-leaved (B_B-1) and Cryptomeria japonica (B_B-2 and PW) forests in the Kasugayama Hill Primeval Forest (Nara, Japan). The change of the seasonal soil respiration rate corresponded to that of the soil temperature. The soil respiration rate was higher in October when fresh organic matter was supplied in the forest floor than in April in spite of the same temperature. The seasonal soil respiration rate of B_B-1 was higher than that of B_B-2, which corresponded to more numbers of bacteria and fungi counted by the dilution plate method and by the direct count method by microscopy in B_B-1 than that of B_B-2. The seasonal soil respiration rate of B_B-2 was higher than that of PW, which corresponded to more microbial biomass by the direct count method by microscopy in B_B-2 than that of PW. The correlation coefficient with the seasonal soil respiration and the soil temperature was higher than that of the monthly soil respiration. The soil respiration carbon was more than the litter fall carbon. It was suggested that the soil respiration included in the carbon dioxide which was emitted by the plant root and soil animal, or that the litter fall supplied to the forest floor included in animal and plant litter.

Keywords: field soil respiration rate, forest soil, litter fall, mineralization rate

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935 Impact of Ozone Produced by Vehicular Emission on Chronic Obstructive Pulmonary Disease

Authors: Mohd Kamil Vakil

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Air Pollution is caused by the introduction of chemicals in the biosphere. Primary pollutants on reaction with the components of the earth produce Secondary Pollutants like Smog. Ozone is the main ingredient of Smog. The ground level ozone is created by the chemical reactions between Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs) in the presence of Sunlight. This ozone can enter inside and call as indoor ozone. The automobile emissions in both moving and idling conditions contribute to the indoor ozone formation. During engine ignition and shutdown, motor vehicles emit the ozone forming pollutants like NOx and VOCs, and the phenomena are called Cold Start and Hot-Soak respectively. Subjects like Chronic Obstructive Pulmonary Disease (COPD) and asthma associated with chronic respiratory diseases are susceptible to the harmful effects of Indoor Ozone. The most common cause of COPD other than smoking is the long-term contract with harmful pollutants like ground-level ozone. It is estimated by WHO that COPD will become the third leading cause of all deaths worldwide by 2030. In this paper, the cold-start and hot-soak vehicle emissions are studied in the context of accumulation of oxides of nitrogen at the outer walls of the building which may cause COPD. The titanium oxide coated building material is further discussed as an absorber of NOx when applied to the walls and roof.

Keywords: indoor air quality, cold start emission, hot-soak, ozone

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934 Membrane Bioreactor versus Activated Sludge Process for Aerobic Wastewater Treatment and Recycling

Authors: Sarra Kitanou

Abstract:

Membrane bioreactor (MBR) systems are one of the most widely used wastewater treatment processes for various municipal and industrial waste streams. It is based on complex interactions between biological processes, filtration process and rheological properties of the liquid to be treated. Its complexity makes understanding system operation and optimization more difficult, and traditional methods based on experimental analysis are costly and time consuming. The present study was based on an external membrane bioreactor pilot scale with ceramic membranes compared to conventional activated sludge process (ASP) plant. Both systems received their influent from a domestic wastewater. The membrane bioreactor (MBR) produced an effluent with much better quality than ASP in terms of total suspended solids (TSS), organic matter such as biological oxygen demand (BOD) and chemical oxygen demand (COD), total Phosphorus and total Nitrogen. Other effluent quality parameters also indicate substantial differences between ASP and MBR. This study leads to conclude that in the case domestic wastewater, MBR treatment has excellent effluent quality. Hence, the replacement of the ASP by the MBRs may be justified on the basis of their improved removal of solids, nutrients, and micropollutants. Furthermore, in terms of reuse the great quality of the treated water allows it to be reused for irrigation.

Keywords: aerobic wastewater treatment, conventional activated sludge process, membrane bioreactor, reuse for irrigation

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933 Numerical Homogenization of Nacre

Authors: M. Arunachalam, M. Pandey

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Nacre, a biological material that forms the inner-layer of sea shells can achieve high toughness and strength by way of staggered arrangement of strong tablets with soft and weak organic interface. Under applied loads the tablets slide over the adjacent tablets, thus generating inelastic deformation and toughness on macroscopic scale. A two dimensional finite element based homogenization methodology is adopted for obtaining the effective material properties of Nacre using a representative volume element (RVE) at finite deformations. In this work, the material behaviour for tablet and interface are assumed to be Isotropic elastic and Isotropic elastic-perfectly plastic with strain softening respectively. Numerical experiments such as uniaxial tension test along X, Y directions and simple shear test are performed on the RVE with uniform displacement and periodic constraints applied at the RVE boundaries to obtain the anisotropic homogenized response and maximum local stresses within each constituents of Nacre. Homogenized material model is then tested for macroscopic structure under three point bending condition and the results obtained are comparable with the results obtained for detailed microstructure based structure, thus homogenization provides a bridge between macroscopic scale and microscopic scale and homogenized material properties obtained from microstructural (RVE) analysis could be used in large scale structural analysis.

Keywords: finite element, homogenization, inelastic deformation, staggered arrangement

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932 Designing Bird-Friendly Kolkata city

Authors: Madhumita Roy

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Kolkata, the city of joy, is an organic city with 45 lakhs of people till date. The increasing population stress is creating a constant pressure on the ground surface which in turn reducing the possible area for plantation. Humans, plants, and birds have a mutualistic relationship, and all are dependent on each other for their survival. Vegetation structure is very important for a bird life because it can be used as a residence, foraging, life cycle, and shelter from predators. On the other hand, in urban areas, buildings and structures also plays a major role for birds habitat w.r.t, nesting, resting, etc. City birds are constantly upgrading their adaptative mechanism with changing urban pattern with modern architectural designs. Urbanisation and unplanned development lead to environmental degradation and bird habitat fragmentation, which have impacts on the degradation of the quality and quantity of bird habitat. Declining green cover and habitat loss affects the diversity and population structure of birds. Their reducing number is an increasing threat not only to the bird community but also to the city as birds are considered as one of the most important environmental indicator. This study aims to check the present avian status like species richness, relative abundance, and diversity of bird species in the context of changing urban pattern in Kolkata city. Nesting strategy in the urban habitat of the avian community is another avenue of interest.

Keywords: urbanisation, avian species, kolkata metropolis, planning

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931 Lamellodiscus spp. (Monogenoidea: Diplectanidae) Infecting the Gill Lamellae of Porgies (Spariformes: Sparidae) in Dakar Coast

Authors: Sikhou Drame, Arfang Diamanka

Abstract:

In Senegal, the fishing sector plays an important role in socio-economic development. However, he is going through enormous difficulties, caused by the scarcity of fish on the Senegalese coast, the overexploitation of fishery resources. Based on this observation, the authorities are betting on the development of aquaculture. It is in this context that the exploration of fish from the highly consumed Sparidae family remains a good solution. Indeed, the Sparidae family has good characteristics for farming at sea. However, parasites can proliferate and destroy the efforts made to cultivate fish in confined areas. the knowledge of these parasites in particular the monogeneans, very specific to the sparidae fishes will allow to better know the bio-ecology of the fishes. Better know the main parasitic monogeneans of the genus Lamellodiscus of sparidae fish of the genus Pagrus harvested in Senegal. It will first be a question of identifying from the observation of the morpho-anatomical characters, Monogeneans of the genus Lamellodiscus, branchial parasites collected from three species of host: Pagrus caeruleostictus , Pagrus auriga and Pagrus africanus. Then to evaluate the spatial and temporary distribution of parasitic indices on two Dakar landing sites (Soumbédioune and Yarakh) and finally to determine their specificity. The fish examined were purchased directly from the landing sites in Dakar and then transported to the laboratory where they were identified, then dissected. The gills were examined under a magnifying glass and the monogeneans were harvested, fixed in 70% ethanol and then mounted between slide and coverslip. The identification of the parasites is based on the observation of the morpho-anatomical characters and on the measurements of the sclerified organs of the haptor and the male copulatory organ. In total out of the 90 individuals examined: Pagrus auriga (30), Pagrus africanus (30) and Pagrus caeruleostictus (30), 6 species of monogeneans of the genus Lamellodiscus (Monogenea, Diplectanidae) are obtained: L. sarculus, L. sigillatus, L.vicinus, L. rastellus, L. africanus n.sp and L. yarakhensis n.sp. Our results show that specimens of small sizes [15-20[cm are the most infested. The values of infestation intensity and abundance are higher in fish from Yarakh and also during the cold season. it is the species Pagrus caeruleostictus which records the highest parasitic loads in the two localities. the majority of the parasites identified have a strict or oioxene specificity. It appears from this study that fish of the genus Pagrus are highly parasitized by monogeneans of the genus Lamellodiscus with a general prevalence of 87.78%. Each infested fish has an average of 30 monogeneans of the genus Lamellodiscus.

Keywords: monogeneans, Lamellodiscus, Dakar coast, genus Pagrus

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930 Thermochemical and Biological Pretreatment Study for Efficient Sugar Release from Lignocellulosic Biomass (Deodar and Sal Wood Residues)

Authors: Neelu Raina, Parvez Singh Slathia, Deepali Bhagat, Preeti Sharma

Abstract:

Pretreatment of lignocellulosic biomass for generating suitable substrates (starch/ sugars) for conversion to bioethanol is the most crucial step. In present study waste from furniture industry i.e sawdust from softwood Cedrus deodara (deodar) and hardwood Shorea robusta (sal) was used as lignocellulosic biomass. Thermochemical pretreatment was given by autoclaving at 121°C temperature and 15 psi pressure. Acids (H2SO4,HCl,HNO3,H3PO4), alkali (NaOH,NH4OH,KOH,Ca(OH)2) and organic acids (C6H8O7,C2H2O4,C4H4O4) were used at 0.1%, 0.5% and 1% concentration without giving any residence time. 1% HCl gave maximum sugar yield of 3.6587g/L in deodar and 6.1539 g/L in sal. For biological pretreatment a fungi isolated from decaying wood was used , sawdust from deodar tree species was used as a lignocellulosic substrate and before thermochemical pretreatment sawdust was treated with fungal culture at 37°C under submerged conditions with a residence time of one week followed by a thermochemical pretreatment methodology. Higher sugar yields were obtained with sal tree species followed by deodar tree species, i.e., 6.0334g/L in deodar and 8.3605g/L in sal was obtained by a combined biological and thermochemical pretreatment. Use of acids along with biological pretreatment is a favourable factor for breaking the lignin seal and thus increasing the sugar yield. Sugar estimation was done using Dinitrosalicyclic assay method. Result validation is being done by statistical analysis.

Keywords: lignocellulosic biomass, bioethanol, pretreatment, sawdust

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929 Bacteriological Characterization of Drinking Water Distribution Network Biofilms by Gene Sequencing Using Different Pipe Materials

Authors: M. Zafar, S. Rasheed, Imran Hashmi

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Very little is concerned about the bacterial contamination in drinking water biofilm which provide a potential source for bacteria to grow and increase rapidly. So as to understand the microbial density in DWDs, a three-month study was carried out. The aim of this study was to examine biofilm in three different pipe materials including PVC, PPR and GI. A set of all these pipe materials was installed in DWDs at nine different locations and assessed on monthly basis. Drinking water quality was evaluated by different parameters and characterization of biofilm. Among various parameters are Temperature, pH, turbidity, TDS, electrical conductivity, BOD, COD, total phosphates, total nitrates, total organic carbon (TOC) free chlorine and total chlorine, coliforms and spread plate counts (SPC) according to standard methods. Predominant species were Bacillus thuringiensis, Pseudomonas fluorescens , Staphylococcus haemolyticus, Bacillus safensis and significant increase in bacterial population was observed in PVC pipes while least in cement pipes. The quantity of DWDs bacteria was directly depended on biofilm bacteria and its increase was correlated with growth and detachment of bacteria from biofilms. Pipe material also affected the microbial community in drinking water distribution network biofilm while Similarity in bacterial species was observed between systems due to same disinfectant dose, time period and plumbing pipes.

Keywords: biofilm, DWDs, pipe material, bacterial population

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928 Probiotics as an Alternative to Antibiotic Use in Pig Production

Authors: Z. C. Dlamini, R. L. S. Langa, A. I. Okoh, O. A. Aiyegoro

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The indiscriminate usage of antibiotics in swine production have consequential outcomes; such as development of bacterial resistance to prophylactic antibiotics and possibility of antibiotic residues in animal products. The use of probiotics appears to be the most effective procedure with positive metabolic nutritional implications. The aim of this study was to investigate the efficacy of probiotic bacteria (Lactobacillus reuteri ZJ625, Lactobacillus reuteri VB4, Lactobacillus salivarius ZJ614 and Streptococcus salivarius NBRC13956) administered as direct-fed microorganisms in weaned piglets. 45 weaned piglets blocked by weight were dived into 5 treatments groups: diet with antibiotic, diet with no-antibiotic and no probiotic, and diet with probiotic and diet with combination of probiotics. Piglets performance was monitored during the trials. Faecal and Ileum samples were collected for microbial count analysis. Blood samples were collected from pigs at the end of the trial, for analysis of haematological, biochemical and IgG stimulation. The data was analysed by Split-Plot ANOVA using SAS statistically software (SAS 9.3) (2003). The difference was observed between treatments for daily weight and feed conversion ratio. No difference was observed in analysis of faecal samples in regards with bacterial counts, difference was observed in ileums samples with enteric bacteria colony forming unit being lower in P2 treatment group as compared with lactic acid and total bacteria. With exception of globulin and albumin, biochemistry blood parameters were not affected, likewise for haematology, only basophils and segmented neutrophils were differed by having higher concentration in NC treatment group as compared with other treatment groups. Moreover, in IgG stimulation analysis, difference was also observed, with P2 treatment group having high concentration of IgG in P2 treatment group as compared to other groups. The results of this study suggest that probiotics have a beneficial effect on growth performances, blood parameters and IgG stimulation of pigs, most effective when they are administered in synergy form. This means that it is most likely that these probiotics will offer a significant benefit in pig farming by reducing risk of morbidity and mortality and produce quality meat that is more affordable to poorer communities, and thereby enhance South African pig industry’s economy. In addition, these results indicate that there is still more research need to be done on probiotics in regards with, i.e. dosage, shelf life and mechanism of action.

Keywords: antibiotics, biochemistry, haematology, IgG-stimulation, microbial count, probiotics

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927 Influence of Agroforestry Trees Leafy Biomass and Nitrogen Fertilizer on Crop Growth Rate and Relative Growth Rate of Maize

Authors: A. B. Alarape, O. D. Aba

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The use of legume tree pruning as mulch in agroforestry system is a common practice to maintain soil organic matter and improve soil fertility in the tropics. The study was conducted to determine the influence of agroforestry trees leafy biomass and nitrogen fertilizer on crop growth rate and relative growth rate of maize. The experiments were laid out as 3 x 4 x 2 factorial in a split-split plot design with three replicates. Control, biomass species (Parkia biglobosa and Albizia lebbeck) as main plots were considered, rates of nitrogen considered include (0, 40, 80, 120 kg N ha⁻¹) as sub-plots, and maize varieties (DMR-ESR-7 and 2009 EVAT) were used as sub-sub plots. Data were analyzed using descriptive and inferential statistics (ANOVA) at α = 0.05. Incorporation of leafy biomass was significant in 2015 on Relative Growth Rate (RGR), while nitrogen application was significant on Crop Growth Rate (CGR). 2009 EVAT had higher CGR in 2015 at 4-6 and 6-8 WAP. Incorporation of Albizia leaves enhanced the growth of maize than Parkia leaves. Farmers are, therefore, encouraged to use Albizia leaves as mulch to enrich their soil for maize production and most especially, in case of availability of inorganic fertilizers. Though, production of maize with biomass and application of 120 kg N ha⁻¹ will bring better growth of maize.

Keywords: agroforestry trees, fertilizer, growth, incorporation, leafy biomass

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926 Occurrence and Geological Setting of the Black Shales Outcrops in Malaysia

Authors: Hassan M. Baioumy, Yuniarti Ulfa

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Paleozoic, Mesozoic and Cenozoic black shales that can be a potential source of energy and precious metals are widely distributed in Malaysia Peninsula, Sarawak and Sabah. Two Paleozoic black shales outcrops were reported in the Langkawi Island belonging to the Cambrian fluvial Machinchang Formation and the Silurian glaciomarine Singa Formation. More the seventeen occurrences of Paleozoic black shales outcrops have been found in the Peninsular Malaysia that range in age from Devonian, Carboniferous, and Permian in the Terengganu, Perlis, Pahang, and Perak States. Mesozoic black shales outcrops occur in several places in both the Peninsular Malaysia and Sarawak. In the Peninsular Malaysia, Triassic black shales occur in the Nami area, Northern Kedah and in the Pahang area. In Sarawak, Triassic black shales have been reported in the Bau area. Cenozoic black shales outcrops were reported in both Sarawak at Miri area and Sabah at the Ranau and Tenom areas. Preliminary mineralogical and geochemical investigations on some of these black shales outcrops showed distinct compositional variations among these black shales outcrops probably due to variations in their source area composition and/or depositional and diagenetic settings of these shales. Some of these shalese also subjected to post-depositional hydrothermal mineralization that enriched these shales with Au-bearing minerals such as pyrite, calchopyrite, and arsenopyrite. Many of the studied black shales outcrops look rich in organic matter, which increase the possibility of using these black shales as an unconventional energy resource.

Keywords: black shales, energy, mineralization, Malaysia

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925 Synthesis and Characterization of Some 1, 2, 3-Triazole Derivatives Containing the Chalcone Moiety and Evaluation for their Antimicrobial and Antioxidant Activity

Authors: Desta Gebretekle Shiferaw, Balakrishna Kalluraya

Abstract:

Triazoles are basic five-membered ring heterocycles with an unsaturated, six-delocalized electron ring system. Since the dawn of click chemistry, triazoles have represented a functional heterocyclic core that has been the foundation of medicinal chemistry. The compounds with 1,2,3-triazole rings can be used in several fields, including medicine, organic synthesis, polymer chemistry, fluorescent imaging, horticulture, and industries, to name a few. Besides that, they found it to have health applications in the prevention and reduction of the risk of diseases, such as anti-cancer, antimicrobial, antiviral, and anti-inflammatory properties. Here, we present the synthesis of twelve 1,2,3-triazolyl chalcone derivatives (4a–l), which were produced in high yields by coupling substituted aldehydes and triazolyl acetophenone (3a–d) in ethanol. The title products were characterized by physicochemical, infrared, nuclear magnetic resonance, and mass spectral methods. The in vitro tests were used to evaluate the antioxidant and antimicrobial activity of each of the prepared molecules. The preliminary assessment and 2,2-diphenyl-1-picrylhydrazyl activity of the title compounds showed significantly higher antibacterial activity and moderate-to-good antifungal and antioxidant activities compared to their standards. This work presents the synthesis of triazolyl chalcone derivatives and their biological activity. Based on the findings, these compounds could be used as lead compounds in antimicrobial and antioxidant research in the future.

Keywords: antibacterial activity, antifungal activity, antioxidant activity, chalcone, 1, 2, 3-triazole

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924 Control System Design for a Simulated Microbial Electrolysis Cell

Authors: Pujari Muruga, T. K. Radhakrishnan, N. Samsudeen

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Hydrogen is considered as the most important energy carrier and fuel of the future because of its high energy density and zero emission properties. Microbial Electrolysis Cell (MEC) is a new and promising approach for hydrogen production from organic matter, including wastewater and other renewable resources. By utilizing anode microorganism activity, MEC can produce hydrogen gas with smaller voltages (as low as 0.2 V) than those required for electrolytic hydrogen production ( ≥ 1.23 V). The hydrogen production processes of the MEC reactor are very nonlinear and highly complex because of the presence of microbial interactions and highly complex phenomena in the system. Increasing the hydrogen production rate and lowering the energy input are two important challenges of MEC technology. The mathematical model of the MEC is based on material balance with the integration of bioelectrochemical reactions. The main objective of the research is to produce biohydrogen by selecting the optimum current and controlling applied voltage to the MEC. Precise control is required for the MEC reactor, so that the amount of current required to produce hydrogen gas can be controlled according to the composition of the substrate in the reactor. Various simulation tests involving multiple set-point changes disturbance and noise rejection were performed to evaluate the performance using PID controller tuned with Ziegler Nichols settings. Simulation results shows that other good controller can provide better control effect on the MEC system, so that higher hydrogen production can be obtained.

Keywords: microbial electrolysis cell, hydrogen production, applied voltage, PID controller

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923 Applying GIS Geographic Weighted Regression Analysis to Assess Local Factors Impeding Smallholder Farmers from Participating in Agribusiness Markets: A Case Study of Vihiga County, Western Kenya

Authors: Mwehe Mathenge, Ben G. J. S. Sonneveld, Jacqueline E. W. Broerse

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Smallholder farmers are important drivers of agriculture productivity, food security, and poverty reduction in Sub-Saharan Africa. However, they are faced with myriad challenges in their efforts at participating in agribusiness markets. How the geographic explicit factors existing at the local level interact to impede smallholder farmers' decision to participates (or not) in agribusiness markets is not well understood. Deconstructing the spatial complexity of the local environment could provide a deeper insight into how geographically explicit determinants promote or impede resource-poor smallholder farmers from participating in agribusiness. This paper’s objective was to identify, map, and analyze local spatial autocorrelation in factors that impede poor smallholders from participating in agribusiness markets. Data were collected using geocoded researcher-administered survey questionnaires from 392 households in Western Kenya. Three spatial statistics methods in geographic information system (GIS) were used to analyze data -Global Moran’s I, Cluster and Outliers Analysis (Anselin Local Moran’s I), and geographically weighted regression. The results of Global Moran’s I reveal the presence of spatial patterns in the dataset that was not caused by spatial randomness of data. Subsequently, Anselin Local Moran’s I result identified spatially and statistically significant local spatial clustering (hot spots and cold spots) in factors hindering smallholder participation. Finally, the geographically weighted regression results unearthed those specific geographic explicit factors impeding market participation in the study area. The results confirm that geographically explicit factors are indispensable in influencing the smallholder farming decisions, and policymakers should take cognizance of them. Additionally, this research demonstrated how geospatial explicit analysis conducted at the local level, using geographically disaggregated data, could help in identifying households and localities where the most impoverished and resource-poor smallholder households reside. In designing spatially targeted interventions, policymakers could benefit from geospatial analysis methods in understanding complex geographic factors and processes that interact to influence smallholder farmers' decision-making processes and choices.

Keywords: agribusiness markets, GIS, smallholder farmers, spatial statistics, disaggregated spatial data

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922 Alumina Supported Cu-Mn-Cr Catalysts for CO and VOCs oxidation

Authors: Krasimir Ivanov, Elitsa Kolentsova, Dimitar Dimitrov, Petya Petrova, Tatyana Tabakova

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This work studies the effect of chemical composition on the activity and selectivity of γ–alumina supported CuO/ MnO2/Cr2O3 catalysts toward deep oxidation of CO, dimethyl ether (DME) and methanol. The catalysts were prepared by impregnation of the support with an aqueous solution of copper nitrate, manganese nitrate and CrO3 under different conditions. Thermal, XRD and TPR analysis were performed. The catalytic measurements of single compounds oxidation were carried out on continuous flow equipment with a four-channel isothermal stainless steel reactor. Flow-line equipment with an adiabatic reactor for simultaneous oxidation of all compounds under the conditions that mimic closely the industrial ones was used. The reactant and product gases were analyzed by means of on-line gas chromatographs. On the basis of XRD analysis it can be concluded that the active component of the mixed Cu-Mn-Cr/γ–alumina catalysts consists of at least six compounds – CuO, Cr2O3, MnO2, Cu1.5Mn1.5O4, Cu1.5Cr1.5O4 and CuCr2O4, depending on the Cu/Mn/Cr molar ratio. Chemical composition strongly influences catalytic properties, this influence being quite variable with regards to the different processes. The rate of CO oxidation rapidly decrease with increasing of chromium content in the active component while for the DME was observed the reverse trend. It was concluded that the best compromise are the catalysts with Cu/(Mn + Cr) molar ratio 1:5 and Mn/Cr molar ratio from 1:3 to 1:4.

Keywords: Cu-Mn-Cr oxide catalysts, volatile organic compounds, deep oxidation, dimethyl ether (DME)

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921 Development of Ecofriendly Ionic Liquid Modified Reverse Phase Liquid Chromatography Method for Simultaneous Determination of Anti-Hyperlipidemic Drugs

Authors: Hassan M. Albishri, Fatimah Al-Shehri, Deia Abd El-Hady

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Among the analytical techniques, reverse phase liquid chromatography (RPLC) is currently used in pharmaceutical industry. Ecofriendly analytical chemistry offers the advantages of decreasing the environmental impact with the advantage of increasing operator safety which constituted a topic of industrial interest. Recently, ionic liquids have been successfully used to reduce or eliminate the conventional organic toxic solvents. In the current work, a simple and ecofriendly ionic liquid modified RPLC (IL-RPLC) method has been firstly developed and compared with RPLC under acidic and neutral mobile phase conditions for simultaneous determination of atorvastatin-calcium, rosuvastatin and simvastatin. Several chromatographic effective parameters have been changed in a systematic way. Adequate results have been achieved by mixing ILs with ethanol as a mobile phase under neutral conditions at 1 mL/min flow rate on C18 column. The developed IL-RPLC method has been validated for the quantitative determination of drugs in pharmaceutical formulations. The method showed excellent linearity for analytes in a wide range of concentrations with acceptable precise and accurate data. The current IL-RPLC technique could have vast applications particularly under neutral conditions for simple and greener (bio)analytical applications of pharmaceuticals.

Keywords: ionic liquid, RPLC, anti-hyperlipidemic drugs, ecofriendly

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920 Micro-Arc Oxidation Titanium and Post Treatment by Cold Plasma and Graft Polymerization of Acrylic Acid for Biomedical Application

Authors: Shu-Chuan Liao, Chia-Ti Chang, Ko-Shao Chen

Abstract:

Titanium and its alloy are widely used in many fields such as dentistry or orthopaedics. Due to their high strength low elastic modulus that chemical inertness and bio inert. The micro-arc oxidation used to formation a micro porous ceramic oxide layer film on Titanium surface and also to improve the resistance corrosion. For improving the biocompatibility, micro-arc oxidation surfaces bio-inert need to introduce reactive group. We introduced boundary layer by used plasma enhanced chemical vapor deposition of hexamethyldisilazane (HMDS) and organic active layer by UV light graft reactive monomer acrylic acid (AAc) therefore we can immobilize Chondroitin sulphate on surface easily by crosslinking EDC/NHS. The surface properties and composition of the modified layer were measured by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) and water contact angle. Water contact angle of the plasma-treated Ti surface decreases from 60° to 38°, which is an indication of hydrophilicity. The results of electrochemical polarization analysis showed that the sample plasma treated at micro-arc oxidation after plasma treatment has the best corrosion resistance. The result showed that we can immobilize chondroitin sulfate successful by a series of modification and MTT assay indicated the biocompatibility has been improved in this study.

Keywords: MAO, plasma, graft polymerization, biomedical application

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919 Evaluation of Biochemical Changes in Some Liver Functions and Anti-Oxidant Parameters in Wistar Rats Exposed to Benzene

Authors: Ezomoh O. Olubunmi, Chukwuma S. Anakwe, Bekewei Progress, Prohp The Prophet

Abstract:

Benzene is a volatile organic compound that is recognised as carcinogenic to humans. The objective of the current investigation was to ascertain the impact of the administration of benzene at varying concentrations on the livers of Wistar rats. The 40 adult female Wistar rats were divided into 10 groups, each consisting of four rats. For 28 days, Group 1 received distilled water, while Groups 2 to 10 were administered 0.04,0.06,0.08,0.2,0.4,0.6,0.8,1.0, and 1.2 ml/kg body weight of analytical grade benzene. Blood samples were obtained through cardiac puncture for liver function assessment, while the animals in groups 1 to 5 were euthanised after the 28th day under chloroform anaesthesia. The animals in groups 6 to 10 died midway through the study period. Antioxidant analysis was conducted on liver tissues that were collected and homogenised. The results indicated a substantial (p<0.05), dose-dependent increase in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) activities as a result of benzene exposure. Additionally, benzene resulted in a substantial reduction in the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in liver tissue, as well as an increase in malondialdehyde (MDA) concentrations, and this effect was dose-dependent. These findings emphasise the hepatotoxic effects of benzene, even at concentrations that are relatively low.

Keywords: benzene, alanine aminotransferase, aspartate aminotransferase, alkaline phosphate, antioxidants, superoxide dismutase, catalase, glutathione peroxidase

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918 Environmental Exposure Assessment among Refuellers at Brussels South Charleroi Airport

Authors: Mostosi C., Stéphenne J., Kempeneers E.

Abstract:

Introduction: Refuellers from Brussels South Charleroi Airport (BSCA) expressed concerns about the risks involved in handling JET-A1 fuel. The HSE Manager of BSCA, in collaboration with the occupational physician and the industrial hygiene unit of the External Service of Occupational Medicine, decided to assess the toxicological exposure of these workers. Materials and methods: Two measurement methods were used. The first was to assay three types of metabolites in urine to highlight the exposure to xylenes, toluene, and benzene in aircraft fuels. Out of 32 refuellers in the department, 26 participated in the sampling, and 23 samples were exploited. The second method targeted the assessment of environmental exposure to certain potentially hazardous substances that refuellers are likely to breathe in work areas at the airport. It was decided to carry out two ambient air measurement campaigns, using static systems on the one hand and, on the other hand, using individual sensors worn by the refuellers at the level of the respiratory tract. Volatile organic compounds and diesel particles were analyzed. Results: Despite the fears that motivated these analyzes, the overall results showed low levels of exposure, far below the existing limit values, both in air quality and in urinary measurements. Conclusion: These results are comparable to a study carried out in several French airports. The staff could be reassured, and then the medical surveillance was modified by the occupational physician. With the aviation development at BSCA, equipment and methods are evolving. Their exposure will have to be reassessed.

Keywords: refuelling, airport, exposure, fuel, occupational health, air quality

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917 Synthesis and Characterization of New Thermotropic Monomers – Containing Phosphorus

Authors: Diana Serbezeanu, Ionela-Daniela Carja, Tachita Vlad-Bubulac, Sergiu Sova

Abstract:

New phosphorus-containing monomers having methoxy end functional groups were prepared from methyl 4-hydroxybenzoate and two different dichlorides with phosphorus, namely phenyl phosphonic dichloride and phenyl dichlorophosphate. The structures of the monomers were confirmed by FTIR and NMR spectroscopy. The assignments for the 1H, 13C and 31P chemical shifts are based on 1D and 2D NMR homo- and heteronuclear correlations (H,H-COSY (Correlation Spectroscopy), H,C-HMQC (Heteronuclear Multiple Quantum Correlation and H,C-HMBC (Heteronuclear Multiple Bond Correlation)) and 31P-13C couplings. The monomers exhibited good solubility in common organic solvents. Dimethyl sulfoxide was to be a good solvent to grow crystals of considerable size which were investigated by X-ray analysis. One of these two new monomers presented thermotropic liquid crystalline behaviour, as revealed by differential scanning calorimetry (DSC), polarized light microscopy (PLM) and X-ray diffraction (XRD). The transition temperature from crystal to liquid crystalline state (K→LC) was 143°C and from the LC to isotropic state (LC→I) was 167°C. Upon heating, bis(4-(methoxycarbonyl)phenyl formed fine textures, difficult to be ascribed to smectic or nematic phases. Upon cooling from the isotropic state, bis(4-(methoxycarbonyl)phenyl exhibited a mosaic-type texture. X-ray diffraction measurements at small angles (SAXS) of bis(4-(methoxycarbonyl)phenyl showed two peaks at 1.8 Å and 3.5 Å, respectively suggesting organization at supramolecular level.

Keywords: phosphorus-containing monomers, polarized light microscopy, structure investigation, thermotropic liquid crystalline properties

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916 Effects of Porcine Oviductal Fluid on In vitro Growth of Dendrobium mirbelianum

Authors: M. Youngsabanant-Areekijseree, C. Thepsithar, K. Sribuddhachart, J. Tananantayot

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Porcine oviductal fluid (pOF) from oviduct, an unused organ from the slaughterhouse, was effectively used for biotechnology studies. The fluid components consisted of micro- and macro-nutrients, amino acids, carbon source and proteins that played important roles in animal cell and embryo development. This was our knowledge on investigating pOF as growth promoting substance in culture medium of an orchid, Dendrobium mirbelianum. Two-leaf shoots were cultured in liquid Vacin and Went (VW) medium as a standard medium supplemented with 2 g/L peptone (Pe) or 100 g/ L boiled-potato water (Po) alone or in combinations, and added with 0, 1, 3 or 5 ml/L pOF. All explants were cultured in a stationary condition for 8 weeks. It was found that medium added with 100 g/L Po and 1 ml/L pOF provided the best results (1.02 g fresh weight, 4.2 shoots, 0.53 cm shoot height, 4.4 protocorms, 11.0 leaves and 5.7 roots with 100% survival) when compared to other medium, but not statistically significant difference from medium added with 100 g/L Po (0.86 g fresh weight, 4.3 shoots, 0.51 cm shoot height, 4.6 protocorms, 12.4 leaves and 6.6 roots with 100% survival). However, VW medium supplemented with 1 or 3 ml/L pOF alone showed the higher percentage of survival (100%) than VW medium (86.67%). It was shown the potential role of pOF as an organic supplement for promoting growth of plants. Acknowledgements—The project was funded by a grant from Silpakorn University Research & Development Institute (SURDI) and Faculty of Science, Silpakorn University, Thailand.

Keywords: Dendrobium mirbelianum, pig, oviductal fluid, in vitro growth

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915 Daily Variations of Polycyclic Aromatic Hydrocarbons (PAHs) in Industrial Sites in an Suburban Area of Sour El Ghozlane, Algeria

Authors: Sidali Khedidji, Noureddine Yassaa, Riad Ladji

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In this study, n-alkanes which are hazardous for the environment and human health were investigated in Sour El Ghozlane suburban atmosphere at a sampling point from April 2013 to Mai 2013. Ambient concentration measurements of n-Alkanes were carried out at a regional study of the cement industry in Sour El Ghozlane. During sampling, the airborne particulate matter was enriched onto PTFE filters by using a two medium volume samplers with or without a size-selective inlet for PM10 and TSP were used and each sampling period lasted approximately 24 h. The organic compounds were characterized using gas chromatography coupled with mass spectrometric detection (GC-MS). Total concentrations for n-Alkanes recorded in Sour El Ghozlane suburban ranged from 42 to 69 ng m-3. Gravimeter method was applied to the black smoke concentration data for Springer seasons. The 24 h average concentrations of n-alkanes contain the PM10 and TSP of Sour El Ghozlane suburban atmosphere were found in the range 0.50–7.06 ng/m3 and 0.29–6.97 ng/m3, respectively, in the sampling period. Meteorological factors, such as (relative humidity and temperature) were typically found to be affecting PMs, especially PM10. Air temperature did not seem to be significantly affecting TSP and PM10 mass concentrations. The guide value fixed by the European Community, 40 μg/m3 was not to exceed 35 days, was exceeded in some samples. However, it should be noted that the value limit fixed by the Algerian regulations 80 μg/m3 has been exceeded in 1 sampler during the period study.

Keywords: n-alkanes, PM10, TSP, particulate matter, cement industry

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914 Study on Biodeterioration of Proteinous Objects in Museums and Toxic Efficacy of Myristica Fragrans and Syzygium Aromaticum Oils against the Larvae of Anthrenus verbasci

Authors: Fatma Faheem, K. Abduraheem

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Museums are custodians of natural and cultural heritage. Objects like tribal dresses, headgears, weapons, musical instruments, manuscripts and other ethnocultural materials housed in museums are prized possessions of intellectual and cultural property of people. Tropical countries like India have a favorable climatic condition for biodeterioration. Organic materials such as leather and parchment objects which form a substantial part of natural history collections of museums across the world are promptly infested by insects like dermestid beetles, tenebrionides, silver fishes, cockroaches and other micro-organisms. The environmental problems caused due to the overuse of pesticides and other non-degradable chemicals have been the matter of serious concern for both the scientists and public in recent years. Synthetic pesticides are very expensive and also highly toxic for humans and its environment. Due to its high health risk factor government has taken severe initiatives on policy of banning it. In order to overcome the problems of biodeterioration, natural biocides should be applied. In this paper, comparative study has been done to investigate the toxic efficacy of Myristica fragrans and Syzygium aromaticum oil in variation with contact and stomach toxicity against larvae of Anthrenus verbasci.

Keywords: biodeterioration, contact toxicity, cultural heritage, natural biocides, natural heritage, stomach toxicity

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913 Extraction of Amorphous SiO₂ From Equisetnm Arvense Plant for Synthesis of SiO₂/Zeolitic Imidazolate Framework-8 Nanocomposite and Its Photocatalytic Activity

Authors: Babak Azari, Afshin Pourahmad, Babak Sadeghi, Masuod Mokhtari

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In this work, Equisetnm arvense plant extract was used for preparing amorphous SiO₂. For preparing of SiO₂/zeolitic imidazolate framework-8 (ZIF-8) nanocomposite by solvothermal method, the synthesized SiO₂ was added to the synthesis mixture ZIF-8. The nanocomposite was characterized using a range of techniques. The photocatalytic activity of SiO₂/ZIF-8 was investigated systematically by degrading crystal violet as a cationic dye under Ultraviolet light irradiation. Among synthesized samples (SiO₂, ZIF-8 and SiO₂/ZIF-8), the SiO₂/ZIF-8 exhibited the highest photocatalytic activity and improved stability compared to pure SiO₂ and ZIF-8. As evidenced by Scanning Electron Microscopy and Transmission electron microscopy images, ZIF-8 particles without aggregation are located over SiO₂. The SiO₂ not only provides structured support for ZIF-8 but also prevents the aggregation of ZIF-8 Metal-organic framework in comparison to the isolated ZIF-8. The superior activity of this photocatalyst was attributed to the synergistic effects from SiO₂ owing to (I) an electron acceptor (from ZIF-8) and an electron donor (to O₂ molecules), (II) preventing recombination of electron-hole in ZIF-8, and (III) maximum interfacial contact ZIF-8 with the SiO₂ surface without aggregation or prevent the accumulation of ZIF-8. The results demonstrate that holes (h+) and •O₂- are primary reactive species involved in the photocatalytic oxidation process. Moreover, the SiO₂/ZIF-8 photocatalyst did not show any obvious loss of photocatalytic activity during five-cycle tests, which indicates that the heterostructured photocatalyst was highly stable and could be used repeatedly.

Keywords: nano, zeolit, potocatalist, nanocomposite

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912 Ultrathin Tin-Silicalite 1 Zeolite Membrane in Ester Solvent Recovery

Authors: Kun Liang Ang, Eng Toon Saw, Wei He, Xuecheng Dong, Seeram Ramakrishna

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Ester solvents are widely used in pharmaceutical, printing and flavor industry due to their good miscibility, low toxicity, and high volatility. Through pervaporation, these ester solvents can be recovered from industrial wastewater. While metal-doped silicalite 1 zeolite membranes are commonly used in organic solvent recovery in the pervaporation process, these ceramic membranes suffer from low membrane permeation flux, mainly due to the high thickness of the metal-doped zeolite membrane. Herein, a simple method of fabricating an ultrathin tin-silicalite 1 membrane supported on alumina tube is reported. This ultrathin membrane is able to achieve high permeation flux and separation factor for an ester in a diluted aqueous solution. Nanosized tin-Silicalite 1 seeds which are smaller than 500nm has been formed through hydrothermal synthesis. The sn-Silicalite 1 seeds were then seeded onto alumina tube through dip coating, and the tin-Silicalite 1 membrane was then formed by hydrothermal synthesis in an autoclave through secondary growth method. Multiple membrane synthesis factors such as seed size, ceramic substrate surface pore size selection, and secondary growth conditions were studied for their effects on zeolite membrane growth. The microstructure, morphology and the membrane thickness of tin-Silicalite 1 zeolite membrane were examined. The membrane separation performance and stability will also be reported.

Keywords: ceramic membrane, pervaporation, solvent recovery, Sn-MFI zeolite

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911 Meiobenthic Diversity off Pudimadaka, Bay of Bengal, East Coast of India with Special Reference to Free-Living Marine Nematodes

Authors: C. Annapurna, Rao M. Srinivasa, Bhanu C. H. Vijaya, M. Sivalakshmi, Rao P. V. Surya

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A study on the community structure of meiobenthic fauna was undertaken during three cruises (June 2008, October 2008 and March 2009). Ten stations at depth between 10 and 40 m off Pudimadaka in Visakhapatnam (Lat.17º29′12″N and Long. 83º00′09″), East coast of India were investigated. Ninety species representing 3 major (meiofaunal) taxa namely foraminifera (2), copepoda (9), nematoda (58) and polychaeta (21) were encountered. Overall, meiofaunal (mean) abundance ranged from 2 individuals to 63 ind. 10cm-² with an average of 24.3 ind.10cm-2. The meiobenthic biomass varied between 0.135 to 0.48 mg.10cm-2 with an average 0.27 ± 0.12. On the whole, nematodes constituted 73.62% of the meiofauna in terms of numerical abundance. Shannon –Wiener index values were 2.053 ± 0.64 (June, 2008), 2.477 ± 0.177 (October 2008) and 2.2815±0.24 (March 2009). Multivariate analyses were used to define the most important taxon in nematode assemblages. Three nematode associations could be recognized off Pudimadaka coast, namely Laimella longicaudata, Euchromodora vulgaris and Sabatieria elongata assemblage (June, 2008); Catanema sp. and Leptosomatum sp. assemblage (October 2008) assemblage; Sabatieria sp. and Setosabatieria sp. assemblage (March 2009). Canonical correspondence analysis showed that temperature, organic matter, silt and mean particle diameter were important in controlling nematode community structure.

Keywords: meiofauna, marine nematode, biodiversity, community structure, India

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910 Nano-Structured Hydrophobic Silica Membrane for Gas Separation

Authors: Sajid Shah, Yoshimitsu Uemura, Katsuki Kusakabe

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Sol-gel derived hydrophobic silica membranes with pore sizes less than 1 nm are quite attractive for gas separation in a wide range of temperatures. A nano-structured hydrophobic membrane was prepared by sol-gel technique on a porous α–Al₂O₃ tubular support with yttria stabilized zirconia (YSZ) as an intermediate layer. Bistriethoxysilylethane (BTESE) derived sol was modified by adding phenyltriethoxysilylethane (PhTES) as an organic template. Six times dip coated modified silica membrane having a thickness of about 782 nm was characterized by field emission scanning electron microscopy. Thermogravimetric analysis, together along contact angle and Fourier transform infrared spectroscopy, showed that hydrophobic properties were improved by increasing the PhTES content. The contact angle of water droplet increased from 37° for pure to 111.5° for the modified membrane. The permeance of single gas H₂ was higher than H₂:CO₂ ratio of 75:25 binary feed mixtures. However, the permeance of H₂ for 60:40 H₂:CO₂ was found lower than single and binary mixture 75:25 H₂:CO₂. The binary selectivity values for 75:25 H₂:CO₂ were 24.75, 44, and 57, respectively. Selectivity had an inverse relation with PhTES content. Hydrophobicity properties were improved by increasing PhTES content in the silica matrix. The system exhibits proper three layers adhesion or integration, and smoothness. Membrane system suitable in steam environment and high-temperature separation. It was concluded that the hydrophobic silica membrane is highly promising for the separation of H₂/CO₂ mixture from various H₂-containing process streams.

Keywords: gas separation, hydrophobic properties, silica membrane, sol–gel method

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909 Tourism Related Activities and Floating Garden in Inle Lake, Myanmar

Authors: Thel Phyu Phyu Soe

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Myanmar started its new political movement in 2011, opening up to trade, encouraging foreign investment, deepening its financial sectors. The tourism is one of the key sectors to make reform process from the perspective of green economy and green growth. The Inle Lake, second largest lake, famous for broad diversity of cultural and natural assets, become one of the country’s main tourism destination. In the study area, local livelihoods are based on a combination of farming (mainly floating garden) wage labor, tourism, and small business. But the Inle lake water body or water surface area decreased by 96.44 km² within 20 years, from 67.98 km² in 1990 to 56.63 km² in 2010. Floating garden cultivation (hydro phonic farm) is a distinguished characteristic of Inle Lake. Two adjacent villages (A and B) were selected to compare the relationship between tourism access and agricultural production. Ground truthing, focus group discussion, and in-depth questionnaires with floating gardeners were carried out. In A village, 57% of the respondents relied tourism as their major income sources, while almost all the households in B village relied floating gardens as major livelihood. Both satellite image interpretation and community studies highlighted that around 80% of the floating garden become fallow after severe drought in 2010 and easy income access to tourism related activities. The villagers can get 20-30 US$ for round trip guiding to major tourist attraction places.Even though tourism is the major livelihood options for the A village, the poorest households (less than 1500 US$ per year) are those who didn’t own transportation property for tourism related activities. In B village, more than 70% of the households relied floating gardens as their major income sources and less participated in tourism related activities because they don’t have motorboat stand connected to the major tourist attraction areas. Access to tourism related activities (having boat stand where they can guide tourists by boat and sell local products and souvenirs) have much impacted on changes in local people livelihood options. However, tourism may have impacts that are beneficial for one group of a society, but which are negative for another. Income inequality and negative impacts can only be managed effectively if they have been identified, measured and evaluated. The severe drought in 2010, instability of lake water level, high expenses for agriculture assisted the local people to participate in easy access tourism related activities.

Keywords: diminishing, floating garden, livelihood, tourism-related income

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908 Applied Free Living Nematode as Bioindicator to Assess Environmental Impact of Dam Construction in Ba Lai Estuary, Vietnam

Authors: Ngo Xuan Quang, Tran Thanh Thai, Ann Vanreusel

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The Ba Lai dam construction was created in 2000 in the Ba Lai estuarine river, Ben Tre province, Vietnam to prevent marine water infiltration, drainage and de-acidification, and to build a reservoir of freshwater for land reclamation in the Ba Lai tributary. However, this dam is considered as an environmental failure for the originally connected estuarine and river ecosystem, especially to bad effect to benthic fauna distribution. This research aims to study applying free living nematode communities’ distribution in disturbance of dam construction as bioindicator to detect environmental impact. Nematode samples were collected together measuring physical–chemical environmental parameters such as chlorophyll, CPE, coliform, nutrient, grain size, salinity, dissolved oxygen, turbidity, conductivity, temperature in three stations within three replicates. Results showed that free living nematode communities at the dam construction was significantly low densities, low diversity (Hurlbert’s index, Hill diversity indices) and very low maturity index in comparison with two remaining stations. Strong correlation of nematode feeding types and communities’ structure was found in relation with sediment grain size and nutrient enrichment such nitrite, nitrate, phosphate and pigment concentration. Moreover, greatly negative link between nematode maturity index with nutrient parameters can serve as warning organic pollution of the Ba Lai river due to dam construction.

Keywords: Ba Lai, dam impact, nematode, environment

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907 Reduced Tillage and Bio-stimulant Application Can Improve Soil Microbial Enzyme Activity in a Dryland Cropping System

Authors: Flackson Tshuma, James Bennett, Pieter Andreas Swanepoel, Johan Labuschagne, Stephan van der Westhuizen, Francis Rayns

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Amongst other things, tillage and synthetic agrochemicals can be effective methods of seedbed preparation and pest control. Nonetheless, frequent and intensive tillage and excessive application of synthetic agrochemicals, such as herbicides and insecticides, can reduce soil microbial enzyme activity. A decline in soil microbial enzyme activity can negatively affect nutrient cycling and crop productivity. In this study, the effects of four tillage treatments; continuous mouldboard plough; shallow tine-tillage to a depth of about 75 mm; no-tillage; and tillage rotation (involving shallow tine-tillage once every four years in rotation with three years of no-tillage), and two rates of synthetic agrochemicals (standard: with regular application of synthetic agrochemicals; and reduced: fewer synthetic agrochemicals in combination with bio-chemicals/ or bio-stimulants) on soil microbial enzyme activity were investigated between 2018 and 2020 in a typical Mediterranean climate zone in South Africa. Four different bio-stimulants applied contained: Trichoderma asperellum, fulvic acid, silicic acid, and Nereocystis luetkeana extracts, respectively. The study was laid out as a complete randomised block design with four replicated blocks. Each block had 14 plots, and each plot measured 50 m x 6 m. The study aimed to assess the combined impact of tillage practices and reduced rates of synthetic agrochemical application on soil microbial enzyme activity in a dryland cropping system. It was hypothesised that the application of bio-stimulants in combination with minimum soil disturbance will lead to a greater increase in microbial enzyme activity than the effect of applying either in isolation. Six soil cores were randomly and aseptically collected from each plot for microbial enzyme activity analysis from the 0-150 mm layer of a field trial under a dryland crop rotation system in the Swartland region. The activities of four microbial enzymes, β-glucosidase, acid phosphatase, alkaline phosphatase and urease, were assessed. The enzymes are essential for the cycling of glucose, phosphorus, and nitrogen, respectively. Microbial enzyme activity generally increased with a reduction of both tillage intensity and synthetic agrochemical application. The use of the mouldboard plough led to the least (P<0.05) microbial enzyme activity relative to the reduced tillage treatments, whereas the system with bio-stimulants (reduced synthetic agrochemicals) led to the highest (P<0.05) microbial enzyme activity relative to the standard systems. The application of bio-stimulants in combination with reduced tillage, particularly no-tillage, could be beneficial for enzyme activity in a dryland farming system.

Keywords: bio-stimulants, soil microbial enzymes, synthetic agrochemicals, tillage

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