Root uptake of lipophilic zinc-rhamnolipid complexes

This study investigated the formation and plant uptake of lipophilic metal-rhamnolipid complexes. Monorhamnosyl and dirhamnosyl rhamnolipids formed lipophilic complexes with copper (Cu), manganese (Mn), and zinc (Zn). Rhamnolipids significantly increased Zn absorption by Brassica napus var. Pinnacle roots in 65Zn-spiked ice-cold solutions, compared with ZnSO4 alone. Therefore, rhamnolipid appeared to facilitate Zn absorption via a nonmetabolically mediated pathway. Synchrotron XRF and XAS showed that Zn was present in roots as Zn-phytate-like compounds when roots were treated with Zn-free solutions, ZnSO4, or Zn-EDTA. With rhamnolipid application, Zn was predominantly found in roots as the Zn-rhamnolipid complex. When applied to a calcareous soil, rhamnolipids increased dry matter production and Zn concentrations in durum (Triticum durum L. cv. Balcali-2000) and bread wheat (Triticum aestivum L. cv. BDME-10) shoots. Rhamnolipids either increased total plant uptake of Zn from the soil or increased Zn translocation by reducing the prevalence of insoluble Zn-phytate-like compounds in roots

Generation gap, gender and shopping enjoyment of shopping mall visitors in western province Sri Lanka

Purpose: Going shopping is a major source of relaxation as well as a daily household chore. However, shopping enjoyment is a burgeoning and rather novel concept, and thus, there is a lack of studies within the cohort, especially with regard to the comparison of the shopping experiences of different generations. This paper explores the nature of shopping enjoyment and measures the impact of the generation gap and gender on visitors’ shopping enjoyment in shopping malls, which records a thriving interest. Design/methodology/approach: In a qualitative survey deploying a convenience sample, 379 usable responses were collected through a self-administered questionnaire from shopping mall visitors in the Western Province of Sri Lanka. Data were analyzed using SPSS (21.0). Findings: Findings of the study indicated that all four generations considered the atmosphere and the environment to be the most important dimensions. Empirical evidence further suggested that Generation Z and Y have the highest enjoyment in their shopping journey within malls compared to other generations, confirming that youth shoppers are the emerging target group for such businesses. Interestingly, it evidenced that shopping is not remaining as a gendered activity anymore, since it is pleasurable for both females and males. Originality: This paper makes a significant contribution to the field by studying shopping enjoyment as a multi-dimensional construct in relation to four generations while being the first such attempt at studying this phenomenon. Implications: Findings are useful for retailers to identify target customers and lucrative markets. Further, shopping malls are required to design to provide more experiences and engagements to customers as a space for pleasure, enjoyment, and entertainment. &nbsp

A Model Based on Mechanics to Predict Settlements in Bioreactor Landfills

Prediction of waste settlement behavior during the construction phase of a landfill is vital to effective functioning of leachate recirculation systems and gas collection pipe network, yet prediction of waste settlement is complex and difficult to perform. Few models, are currently available which can be used to calculate landfill settlement of the entire waste thickness after closure without accounting for variation in density and other parameters with depth. By starting after closure, these models do not account for settlements during construction. The use of entire depth does not allow for the calculation of strains at different depths. When landfills are operated as bioreactors, waste decomposition and gas production are accelerated making the problem more complicated. Rapid degradation results in a significant impact on waste properties, settlement and stability. Accurate prediction of this rapid change in volume is of importance in estimating airspace, planning construction sequence, designing covers as well as planning for expansions. This paper focuses on the behavior of the density and settlements of waste with time and space and proposes a new mathematical model based on mechanics which is capable of computing settlements during construction of landfills. The impact of leachate recirculation and different waste types on settlement behavior of a landfill is also accounted in the proposed model

CREEP OF SMALL DIAMETER TIMBER POLES

It has become necessary to encourage the use of small diameter timber poles (plantationthinnings) as building timber particularly in roof construction, as the supply of betterknown indigenous species can no longer meet the increasing demand for constructiontimber. Eucalyptus and Pinus species were introduced to Sri Lanka some years ago and atpresent there exists a large area under their plantation. While the larger diameter trees areused in pole form for transmission poles or are processed for furniture, the thinnings havehad little use. Preliminary studies were carried out to assess the feasibility of using thethinnings as roof timber. The mechanical properties were found to be adequate. Boththese species however need to be preservative treated to increase their durability. Borondiffusion was considered a cost effective method of treatment provided the poles are usedwhile still green. Previous studies have shown that the poles removed from a Boronpreservative tank took 3 to 4 months to reach equilibrium moisture content. Thus theymust be allowed to dry out under load.The limiting of deflection often controls the design of seasoned timber beams. It is thusexpected that limiting deflection, will be more the controlling design requirement for thegreen poles drying out under load. The magnitude of long term or creep deflection thatoccurs as the poles dry out under load is thus significant and needs to be determined.This paper describes an investigation into the creep behaviour of initially green smalldiameter timber poles drying out under load. The magnitude of a factor that can be appliedto instantaneous elastic deformation to evaluate long term deformation is determinedexperimentally for timber poles of Eucalyptus and Pinus species of different diametersdrying out under a range of bending stresses.

A Comprehensive Model for Anaerobic Degradation in Bio-Reactor Landfills

A new generation of sustainable landfill was designed and constructed in the City of Calgary, Canada to achieve sustainable municipal solid waste (MSW) management. This sustainable landfill called “biocell” involves sequential operation of a landfill cell to produce methane gas during the first stage of anaerobic degradation and in-situ composting within the cell footprint. Once methane recovery is minimal, the second stage aerobic degradation initiated by injecting air through methane recovery system and finally landfill is mined for resource and space recovery in the third stage. The resources that can be recovered include compost like material and recyclables such as plastics, metal, and glass. Non-recovered waste but with high energy content can be used as refuse derived fuel. The practice of this approach will no longer require the need to allocate valuable land for new landfills on an on-going basis. There is leachate re-circulation and environmental monitoring to enhance biodegradation in the biocell. The biocell eliminate problems of ground/surface water contamination, landfill gas emission and the need for new land to use for waste disposal. However, currently there is limited knowledge on landfill mining and in order to estimate the best time to initiate landfill mining a comprehensive mathematical model was developed. The model developed solves the mass and energy balance of waste decay, which computes the rate of gas generation, change of gas and gas flux through the system. This study focuses on anaerobic phase of biodegradation of biomass and the degradation of the biomass was assumed to follow first order kinetics. The decomposing bio mass is represented as cellulose for energy balance computation, which is a major constitution of the MSW. The degradation of bio mass due to micro-organisms generates methane, carbon dioxide and water as the final products and the reaction is exothermic. In this model using the decay of waste computed from mass balance and cellulose as equivalent chemical representing the waste a relationship between the mass degraded with time was established. The heat released due to anaerobic decay is computed and hence computes the increase in biocell temperature. Then selecting the representative decay constant for the computed biocell temperature, the decomposition of waste was computed for the next time step. The above computation is continued in order to obtain the landfill settlement, temperature and the movement of landfill gas and leachate

Evaluation of Community Resilience Aspects of Sri Lankan Coastal Districts

This research is carried out to evaluate important community resilience aspects of coastal districts in Sri Lanka and to provide suitable recommendations to strengthen them. After carrying out an indepth literature survey and interviewing key personnel who are involved in the field of Disaster Management and Disaster Risk Reduction, existing status of the coastal hazards, multi-hazard assessments, early warning mechanisms, national policies, guidelines and efforts and regional cooperation were identified. During the literature survey, it was observed that Sri Lanka has developed a Hazard profile for the country and has an Early Warning Dissemination System which seems to function quite well by the book. What is more, the country is in the process of orienting the existing national policies and guidelines with the post 2015 global standards such as the Sendai framework and Sustainable Development Goals. Sri Lanka being a member of Indian Ocean Tsunami Warning and Mitigation System (IOTWMS) and Regional Integrated Multi-Hazard Early Warning System for Africa and Asia (RIMES) depicts that the country has a good regional cooperation in terms of Early Warning. Even though Sri Lanka lacks efficient and sustainable resilience mechanisms focused on the coastal communities, national efforts are underway to build up the coastal resilience. Training and public awareness campaigns, efficient funds, properly maintained hierarchy and concern to the coastal ecosystems are some of the enablers identified in this study which are associated in building coastal resilience. Developing and updating a multi-hazard map, improving the interagency cooperation and driving towards a people-centred Multi-Hazard Early Warning System (MHEWS) are some of the recommendations given after the analysi

FACTORS LIMITING SEED GERMINATION IN Scyphiphora hydrophyllacea GAERTN f. AND Pempilis acidula J R & FORST

Scyphiphora hydrophyllacea is a highly threatened true mangrove confined to JafTna and asingle locality in Kalpitiya (Trimen 1974; Dassanayake and Clayton 1998). Pemphisacidula is restricted to small pockets in few coastal areas. Both produce fruits and seedsnevertheless, seedlings were not observed in their natural habitats. Factors governing seedgermination in these two species were studied. For all experiments, randomly collected ripe.seed samples were used within two weeks of collection. Moist filter paper method was usedand daily observations were recorded.In P. acidula, seed production was 100%. Percentage of fruit bearing seeds was 10% in S.hydrophyllacea, but none of them gave rise to healthy seedlings. Seed germination of bothspecies was 0% in water collected from respective natural habitats. In P. acidula%germination was 35% in 75% and 40% in 87.5% dilution of water from natural habitat.In distilled water, 65% of the seeds germinated. Continuous washing of seeds in runningtap water increased percentage germination to 75%.Dormancy breaking treatments such as heat treatment, seed nicking, acid base treatment,cold treatment and treatment with gibberellic acid did not increase germination abovenormal 65% value.Exposure to natural light, photoperiod and oxygen level also affected seed germination.Analysis of data consisted of ANa VA at 5% level of significance using Minitab package.In P. acidula, salinity of soil water (up to 34 ppt) and salt deposits on seed coat seem to bemajor causes hindering seed germination in natural habitat. Seeds buried ill sand may alsonot receive adequate amount of light (Isikawa 1962; Fujii 1962). Oxygen concentrationmay 1I0tbe enough when the ground is covered with water during tides. Lack of seedlingsmay therefore be due to lack of seed germination under natural conditions.In S. hydrophyllacea, very low percentage of seed bearing fruits and inability to producehealthy seedlings explain why it has become highly threatened. Production of large numberof seedless fruits and inability to produce normal seedlings could be due to genetic disorderin seeds, which is a very common phenomenon known as inbreeding depression inisolated, small populations.Presence of self-sterility and the absence of pollinator niight be some other reasons. Hence,studies on the possibility of propagating S. hydrophyllacea by vegetative means areurgently needed to conserve this highly threatened tree species.

Fate of Zinc Oxide Nanoparticles Coated onto Macronutrient Fertilizers in an Alkaline Calcareous Soil

Citation: Milani, N., Hettiarachchi, G. M., Kirby, J. K., Beak, D. G., Stacey, S. P., & McLaughlin, M. J. (2015). Fate of Zinc Oxide Nanoparticles Coated onto Macronutrient Fertilizers in an Alkaline Calcareous Soil. Plos One, 10(5), 16. doi:10.1371/journal.pone.0126275Zinc oxide (ZnO) nanoparticles may provide a more soluble and plant available source of Zn in Zn fertilizers due to their greater reactivity compared to equivalent micron-or millimetresized (bulk) particles. However, the effect of soil on solubility, spatial distribution and speciation of ZnO nanoparticles has not yet been investigated. In this study, we examined the diffusion and solid phase speciation of Zn in an alkaline calcareous soil following application of nanoparticulate and bulk ZnO coated fertilizer products (monoammonium phosphate (MAP) and urea) using laboratory-based x-ray techniques and synchrotron-based mu-x-ray fluorescence (mu-XRF) mapping and absorption fine structure spectroscopy (mu-XAFS). Mapping of the soil-fertilizer reaction zones revealed that most of the applied Zn for all treatments remained on the coated fertilizer granule or close to the point of application after five weeks of incubation in soil. Zinc precipitated mainly as scholzite (CaZn2(PO4)(2)center dot 2H(2)O) and zinc ammonium phosphate (Zn(NH4)PO4) species at the surface of MAP granules. These reactions reduced dissolution and diffusion of Zn from the MAP granules. Although Zn remained as zincite (ZnO) at the surface of urea granules, limited diffusion of Zn from ZnO-coated urea granules was also observed for both bulk and nanoparticulate ZnO treatments. This might be due to either the high pH of urea granules, which reduced solubility of Zn, or aggregation (due to high ionic strength) of released ZnO nanoparticles around the granule/point of application. The relative proportion of Zn(OH)(2) and ZnCO3 species increased for all Zn treatments with increasing distance from coated MAP and urea granules in the calcareous soil. When coated on macronutrient fertilizers, Zn from ZnO nanoparticles (without surface modifiers) was not more mobile or diffusible compared to bulk forms of ZnO. The results also suggest that risk associated with the presence of ZnO NPs in calcareous soils would be the same as bulk sources of ZnO

AN INVESTIGATION OF SOME PHENOLOGICAL EVENTS IN THREE MANGROVE GENERA WITH REFERENCE TO SELECTED CLIMATIC FACTORS IN NEGOMBO LAGOON

Mangroves consist of ICw tree species which are adapted to grow under tidal conditions.Studies on the phenology of mangroves is scarce. The main objective of this research wasto study major phenological cycles of some overexploited species and to compare thesewith previous observations on the same species samples from three other lagoons.Phenological cycles of leafing. flowering and fruiting of R hizophora apiculata, R.Mucronata, Bru.guicra gvmnorhi:a. B. Sexangula and Ccriops taga! were studies for aperiod of 24 months at selected sites in Negombo lagoon which is located in the wet zoneof Sri Lanka. Phenological cycles were followed and phenological indices were calculated.Thcse d;lla were compared with monthly variations in rain fall. temperature and humidityof the study area.Leal production showed two distinct maxima per year in all species. Rainfall seemed toexert a great influence on leaf rcflushing. Peaks of leaf rcflushing coincided with lulls ofIluwcriru; and fruiting. Annual bimodality was observed for flowering fruiting in allspecies. These species showed unimodal pattern of some of these events when they weregrowing in dry zonePhenological cycles constructed using data obtained show no intraspecific variation in thetime required to complete a single flowering-fruiting cycle, Similarly. intragcncricvariation was absent in the life time of leafing cyclesIn Rh izophora species. leaf bud jut emerged took I - 1,5 yrs to complete a single cyclewhere as in Bruguicra species this period was 2 - 2,5 yrs, In CeriOI)S tagal, it was 1,5 - 2yrs. Similarly. a flower bud of Rhizophora species took 1,5 - 2.5 yrs, Brugcciera species Iyr and C tagu! about 1,5 yrs to form a mature hypocotyl.A comparison of these observations with findings of the previous study proves thatphenological cycles in studies species are environmentally dependent and not speciesspecific,Unimodality of floral phenology in dry zone species may he due to the seasonal variation inground water salinity,