86 research outputs found

    Low-cost defluoridation of water using broken bricks

    Get PDF
    A low cost domestic defluoridator has been developed by the National Water Supply & Drainage Board of Sri Lanka to remove excess fluoride in drinking water to avoid endemic Fluorosis. Broken pieces of freshly burnt bricks are used as filter media in these units. A kinetic model for fluoride uptake in the filter with broken bricks as defluoridating agent is considered and the model parameters are estimated using experimental data. Data concerning the uptake of fluoride on broken brick pieces are obtained from water in batch in the defluoridator. The reaction rate parameter, k, and the capacity parameter fm are estimated and the model fits the collected data satisfactorily. fm is estimated to 0.10 mg/g and k which is a function of initial concentration varies between 0.001 and 0.0005 L/ (mg.ho.5) for low and high initial concentration. Broken bricks could be used as filter media for concentration of fluoride in raw water around 2 mg/1

    Accurate Crop Spraying with RTK and Machine Learning on an Autonomous Field Robot

    Full text link
    The agriculture sector requires a lot of labor and resources. Hence, farmers are constantly being pressed for technology and automation to be cost-effective. In this context, autonomous robots can play a very important role in carrying out agricultural tasks such as spraying, sowing, inspection, and even harvesting. This paper presents one such autonomous robot that is able to identify plants and spray agro-chemicals precisely. The robot uses machine vision technologies to find plants and RTK-GPS technology to navigate the robot along a predetermined path. The experiments were conducted in a field of potted plants in which successful results have been obtained.Comment: 7 pages, 12 figures, Journa

    Phytosociological analysis of restored and managed grassland habitat within an urban national park

    Get PDF
    Floyd Bennett Field (FBF), 579 ha in extent, is a division of Gateway National Recreation Area. It is the site of a former airfield, constructed by filling salt marshes with dredged materials. Except for the portion known locally as the “North Forty,” all sections of FBF have been cut over to maintain low vegetation. A grassland management plan (GRAMP) for 165 ha was initiated in 1986, to maintain habitats for open-country birds. Over the next few years, encroaching woody vegetation was removed manually and mechanically from the management area. Since then, it has been maintained as a grassland and receives annual mowing, as well as continued manual removal of the larger woody sprouts. A portion of the GRAMP management area (III) was selected for intensive study of vegetation composition. A grid system was created and vegetation cover was estimated in 127, 1 m × 1 m quadrats. The quadrats were subjected to cluster analysis (CA). Eleven clusters were recognized. These clusters were treated as “plant associations.” The following types were distinguished: (native) little bluestem–dewberry grassland, six-weeks fescue annual grassland, a grass marsh, a rush marsh, a switchgrass dry grassland, and a deer-tongue panicgrass grassland; (exotic) mugwort herbland, oriental bittersweet-Japanese honeysuckle vineland, Kentucky bluegrass-mixed grassland, Japanese knotweed tall herbland, and spotted knapweed-common St. Johnswort herbland. The little bluestem–dewberry association accounted for nearly half of all quadrats; six subclusters were recognized. The plant associations determined by CA were compared with plant lists compiled during traverses of all of the map categories in the six GRAMP Areas (I, II, III, IV, V, VI). A table was created to relate the quantitative data of the plant associations to the appropriate map categories. A nonmetric multidimensional scaling ordination (NMDS) was performed on the quadrat data. Finally, the plant associations were compared with those described in the literature of local vegetation studies. The mowing program has been effective in decreasing woody plant cover and has permitted the invasion of a few taxa into monospecific communities, but attendant disturbance of the substrate is likely to cause an increase in exotic plant taxa. As earlier studies noted, mowing has caused the increase in cover of sod-forming grass, and bare ground has virtually disappeared in the managed area. This has negative implications for the maintenance of those grassland bird species that require open ground for nesting

    Determination of the scale of pattern and distribution in Helicteres isora L (Sterculiaceae)

    Get PDF
    Helicteres isora L. is a traditional multipurpose plant used by indigenous community and villagers inall the three major climatic zones in Sri Lanka. It naturally occurs in the edges of forests and indisturbed secondary vegetation. It is fastly disappearing in the wet zone due to land clearing and highextraction rates. The present study was conducted to understand the pattern and the scale of distributionof H. isora in order to provide information for biodiversity conservation and further to enable thesustainable use.Twelve natural populations were identified in wet, intermediate and dry zones and the distribution ofindividuals was studied using gradient directed transect method. The t test was performed for eachpopulation to detect the pattern of distribution and pattern analysis was carried out to determine thescale of pattern.Out of twelve populations surveyed, only five populations showed contagious distribution (p < 0.05)while seven populations showed random pattern of distribution. This indicates that the populations ofH isora do not fall into a particular pattern of distribution in nature. This may be due to the highdisturbance present in and around the populations.The results of the pattern analysis reveal more peaks in smaller block sizes (2m2) and larger blocksizes (32m2) indicating aggregated pattern in respective block sizes. Peaks in smaller block sizes aredue to the morphology of the plant as it produces new plants from roots. Peaks at larger block sizesare due to the extrinsic factors and these results could be utilized in the in- situ conservation of Hisora .

    Do Native Parasitic Plants Cause More Damage to Exotic Invasive Hosts Than Native Non-Invasive Hosts? An Implication for Biocontrol

    Get PDF
    Field studies have shown that native, parasitic plants grow vigorously on invasive plants and can cause more damage to invasive plants than native plants. However, no empirical test has been conducted and the mechanism is still unknown. We conducted a completely randomized greenhouse experiment using 3 congeneric pairs of exotic, invasive and native, non-invasive herbaceous plant species to quantify the damage caused by parasitic plants to hosts and its correlation with the hosts' growth rate and resource use efficiency. The biomass of the parasitic plants on exotic, invasive hosts was significantly higher than on congeneric native, non-invasive hosts. Parasites caused more damage to exotic, invasive hosts than to congeneric, native, non-invasive hosts. The damage caused by parasites to hosts was significantly positively correlated with the biomass of parasitic plants. The damage of parasites to hosts was significantly positively correlated with the relative growth rate and the resource use efficiency of its host plants. It may be the mechanism by which parasitic plants grow more vigorously on invasive hosts and cause more damage to exotic, invasive hosts than to native, non-invasive hosts. These results suggest a potential biological control effect of native, parasitic plants on invasive species by reducing the dominance of invasive species in the invaded community

    Genomic insights into rapid speciation within the world's largest tree genus Syzygium

    Get PDF
    Acknowledgements Y.W.L. was supported by a postgraduate scholarship research grant from the Ministry of National Development, Singapore awarded through the National Parks Board, Singapore (NParks; NParks’ Garden City Fund). Principal research funding from NParks and the School of Biological Sciences (SBS), Nanyang Technological University (NTU), Singapore, is acknowledged. We thank Peter Preiser, Associate Vice President for Biomedical and Life Sciences, for facilitating NTU support, and Kenneth Er, CEO of NParks, for facilitating research funding through that organisation. V.A.A. and C.L. were funded by SBS, NTU for a one-year research leave. V.A.A. and C.L. also acknowledge support from the United States National Science Foundation (grants 2030871 and 1854550, respectively). S.R. was supported by a postdoctoral research fellowship under the NTU Strategic Plant Programme. S.R. and N.R.W.C. acknowledge funding from NTU start-up and the Academy of Finland (decisions 318288, 319947) grants to J.S. Fieldwork conducted by Y.W.L. was supported by an Indonesian Government RISTEK research permit (Application ID: 1517217008) and an Access License from the Sabah State government [JKM/MBS.1000-2/2JLD.7(84)]. T.N.C.V. is grateful to the AssemblĂ©e de la Province Nord and AssemblĂ©e de la Province Sud (New Caledonia) for facilitating relevant collection permits. A.N. was partly supported by the Research Project Promotion Grant (Strategic Research Grant No. 17SP01302) from the University of the Ryukyus, and partly by the Environment Research and Technology Development Fund (JPMEERF20204003) from the Environmental Restoration and Conservation Agency of Japan. Fieldwork in Fiji conducted by R.B. was hosted and facilitated by Elina Nabubuniyaka-Young (The Pacific Community’s Centre for Pacific Crops and Trees, Fiji). We thank the NTU-Smithsonian Partnership for tree data obtained for the Bukit Timah Nature Reserve (BTNR) long-term forest dynamics plots. Administrative support provided by Mui Hwang Khoo-Woon and Peter Ang at the molecular laboratory of the Singapore Botanic Gardens (SBG) is acknowledged. Rosie Woods and Imalka Kahandawala (DNA and Tissue Bank, Royal Botanic Gardens, Kew) facilitated additional DNA samples. Daniel Thomas (SBG) and Yan Yu (Sichuan University) commented on biogeographical analyses. NovogeneAIT in Singapore is acknowledged for personalised sequencing service.Peer reviewedPublisher PD

    Genomic insights into rapid speciation within the world's largest tree genus Syzygium

    Get PDF
    The relative importance of the mechanisms underlying species radiation remains unclear. Here, the authors combine reference genome assembly and population genetics analyses to show that neutral forces have contributed to the radiation of the most species-rich tree genus Syzygium. Species radiations, despite immense phenotypic variation, can be difficult to resolve phylogenetically when genetic change poorly matches the rapidity of diversification. Genomic potential furnished by palaeopolyploidy, and relative roles for adaptation, random drift and hybridisation in the apportionment of genetic variation, remain poorly understood factors. Here, we study these aspects in a model radiation, Syzygium, the most species-rich tree genus worldwide. Genomes of 182 distinct species and 58 unidentified taxa are compared against a chromosome-level reference genome of the sea apple, Syzygium grande. We show that while Syzygium shares an ancient genome doubling event with other Myrtales, little evidence exists for recent polyploidy events. Phylogenomics confirms that Syzygium originated in Australia-New Guinea and diversified in multiple migrations, eastward to the Pacific and westward to India and Africa, in bursts of speciation visible as poorly resolved branches on phylogenies. Furthermore, some sublineages demonstrate genomic clines that recapitulate cladogenetic events, suggesting that stepwise geographic speciation, a neutral process, has been important in Syzygium diversification.Peer reviewe

    The uses of Chrysomya megacephala (Fabricius, 1794)(Diptera: Calliphoridae) in forensic entomology:

    Get PDF
    Chrysomya megacephala (Fabricius, 1794) occurs on every continent and is closely associated with carrion and decaying material in human environments. Its abilities to find dead bodies and carry pathogens give it a prominence in human affairs that may involve prosecution or litigation, and therefore forensic entomologists. The identification, geographical distribution and biology of the species are reviewed to provide a background for approaches that four branches of forensic entomology (urban, stored-product, medico-criminal and environmental) might take to investigations involving this fly

    Outline of Fungi and fungus-like taxa

    Get PDF
    This article provides an outline of the classification of the kingdom Fungi (including fossil fungi. i.e. dispersed spores, mycelia, sporophores, mycorrhizas). We treat 19 phyla of fungi. These are Aphelidiomycota, Ascomycota, Basidiobolomycota, Basidiomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Entorrhizomycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. The placement of all fungal genera is provided at the class-, order- and family-level. The described number of species per genus is also given. Notes are provided of taxa for which recent changes or disagreements have been presented. Fungus-like taxa that were traditionally treated as fungi are also incorporated in this outline (i.e. Eumycetozoa, Dictyosteliomycetes, Ceratiomyxomycetes and Myxomycetes). Four new taxa are introduced: Amblyosporida ord. nov. Neopereziida ord. nov. and Ovavesiculida ord. nov. in Rozellomycota, and Protosporangiaceae fam. nov. in Dictyosteliomycetes. Two different classifications (in outline section and in discussion) are provided for Glomeromycota and Leotiomycetes based on recent studies. The phylogenetic reconstruction of a four-gene dataset (18S and 28S rRNA, RPB1, RPB2) of 433 taxa is presented, including all currently described orders of fungi
    • 

    corecore