219,108 research outputs found

    Corallorhiza odontorhiza Nutt.

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    https://thekeep.eiu.edu/herbarium_specimens_byname/16623/thumbnail.jp

    Utilization of aquatic plants: a method to enhance the productivity of water in seasonal tanks in the Anuradhapura District

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    Heavy infestations of aquatic plants in a water body cause considerable economic and ecological losses. Many seasonal tanks in the Anuradhapura District suffer from this problem and cannot be neglected in water resource development and management schemes. This study was focused on the uses of aquatic plants and the problems caused by huge manifestations of aquatic plants in the selected seasonal tanks in the Anuradhapura District. The study was conducted in four seasonal tanks viz., Galkulama, Thirappane Maradankadawala and Thibbatuwewa in the Anuradhapura District. Information on the utilization of aquatic plants, exploitation level and harmful effects were gathered by using a structured questionnaire to interview people who were residing close to the study sites. The attitudes of the public towards the aquatic plants i.e., conservation of aquatic plants, the potential uses of native plants and harmful effects of invasive aquatic plants were collected. Twelve species were identified as economically important aquatic plants through the questionnaire survey. Among the 50 respondents, 92 % utilized aquatic plants for food, 58 % utilized flowers for offerings and decorations, 52 % utilized aquatic plants for medicinal purposes, 42 % utilized them as ornamental plants, 30 % used them as bio-fertilizers and 28 % utilized them for weaving. The edible aquatic plants consumed by the rural community in the Anuradhapura District are Ipomoea aquatica (72 %), Alternanthera sessilis (66 %), Nelumbo nucifera (64 %), Nymphaea pubescens (60 %) and Aponogeton spp. (52 %). Some edible aquatic plants, namely Neptunia oleracea, Ottelia alismoides and Ceratopteris thalictriodes, which are present in the Anuradhapura District, are not consumed, although these are consumed in many other countries. N. nucifera is the most commonly used flower for offerings in the temples and for decorations. In addition, N. pubescens, Nymphaea nouchali are also used for flowers. Bacopa monnieri, N. nucifera, Acanthus illicifolia, N. nouchali and Aponogeton spp. have been recorded as medicinally important plants. Though there are many ornamentally important aquatic plants, only N. pubescens, N. nouchali, B. monnieri, Nymphoides hydrophylla are used. Salvinia molesta and Eichhornia crassipes are the two aquatic plants commonly used as bio fertilizers. With reference to the questionnaire survey, there were seven major problems that were discovered to exist due to heavy infestations of aquatic weeds in the water bodies viz., sedimentation and unsuitability for domestic use, interference with navigation, effects on fisheries, blocking irrigation canals and evapotranspiration. The most problematic plants in the Anuradhapura District include E. crassipes, N. nucifera, S. molesta, Pistia stratiotes and Ceratophyllum demersum. Economically important aquatic plants available in the shallow water bodies of the Anuradhapura District, are marginally utilized, when compared with the utilization of aquatic plants in the global scenario. There appears to be a lack of a well organized action plan to cope with this situation. The public suffer a lot from the problems created by the heavy mass of aquatic plants, which covered the village tanks. The public are, however, willing to get organized and to engage in a participatory approach to restore their water bodies. There is a need for research and development of management strategies for the sustainable utilization of these valuable resources. Awareness programs should be conducted to promote sustainable utilization of aquatic plants. Creating awareness among the people about the nutritional and economic benefits of these natural resources will be useful for Sri Lanka, as a developing nation.Length: pp.23-32Aquatic plantsTanks

    Evaluation of macrophyte control in 38 Florida lakes using triploid grass carp

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    Florida’s large number of shallow lakes, warm climate and long growing season have contributed to the development of excessive growths of aquatic macrophytes that have seriously interfered with many water use activities. The introduction of exotic aquatic macrophyte species such as hydrilla ( Hydrilla verticillata ) have added significantly to aquatic plant problems in Florida lakes. The use of grass carp ( Ctenopharyngodon idella ) can be an effective and economical control for aquatic vegetation such as hydrilla. Early stocking rates (24 to 74 grass carp per hectare of lake area) resulted in grass carp consumption rates that vastly exceeded the growth rates of the aquatic plants and often resulted in the total loss of all submersed vegetation. This study looked at 38 Florida lakes that had been stocked with grass carp for 3 to 10 years with stocking rates ranging from < 1 to 59 grass carp per hectare of lake and 1 to 207 grass carp per hectare of vegetation to determine the long term effects of grass carp on aquatic macrophyte communities. The median PAC (percent area coverage) value of aquatic macrophytes for the study lakes after they were stocked with grass carp was 14% and the median PVI (percent volume infested) value of aquatic macrophytes was 2%. Only lakes stocked with less than 25 to 30 fish per hectare of vegetation tended to have higher than median PAC and PVI values. When grass carp are stocked at levels of > 25 to 30 fish per hectare of vegetation the complete control of aquatic vegetation can be achieved, with the exception of a few species of plants that grass carp have extreme difficulty consuming. If the management goal for a lake is to control some of the problem aquatic plants while maintaining a small population of predominately unpalatable aquatic plants, grass carp can be stocked at approximately 25 to 30 fish per hectare of vegetation

    Limnology of Four Bauxite Open-Pit Lakes

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    The aquatic flora and fauna and 18 physicochemical characteristics of four bauxite open-pit lakes were studied from September 1969 to August 1970. The least acid lake (pH 3.4-4.4) supported 49 different aquatic insects, plankton, and higher aquatic plants. The most acid lake (pH 2.7-3.2) supported only 26 different plants and animals. Bauxite open-pit lakes within the pH range studied appear to be as relatively unproductive as their coal strip-mine lake counterparts, with which they share physicochemical and biological characteristics. Benthic macrofaunal diversity and abundance appear to be related more closely to distribution and abundance of leaf detritus than to hydrogen-ion concentration

    Remote sensing of aquatic plants

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    Various sensors were tested in terms of their ability to detect and discriminate among noxious aquatic macrophytes. A survey of researchers currently studying the problem and a brief summary of their work is included. Results indicated that the sensor types best suited to assessment of the aquatic environment are color, color infrared, and black-and-white infrared film, which furnish consistently high contrasts between aquatic plants and their surroundings

    Aquatic plants

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    Aquatic plants for removal of mevinphos from the aquatic environment

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    Fragrant waterlily (Nymphaea odorata, Ait.), joint-grass (Paspalum distichum L.), and rush (Juncus repens, Michx.) were used to evaluate the effectiveness of vascular aquatic plants in removing the insecticide mevinphos (dimethyl-1-carbomethoxy-1propen-2-yl phosphate) from waters contaminated with this chemical. The emersed aquatic plants fragrant waterlily and joint-grass removed 87 and 93 ppm of mevinphos from water test systems in less than 2 weeks without apparent damage to the plants; whereas rush, a submersed plant, removed less insecticide than the water-soil controls. Water-soil control still contained toxic levels of this insecticide, as demonstrated by fish bioassay studies, after 35 days

    Evaluación de dosis en pacientes sometidos a procedimientos de angiografía y angioplastía coronaria transluminal percutanea

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    Este trabajo tiene como objetivo aplicar protocolos internacionales de dosimetr√≠a en pacientes sometidos a procedimientos de radiolog√≠a intervencionista guiada por fluoroscopia (IGF) con el fin de establecer los valores t√≠picos (VT) aplicables a pacientes sometidos a procedimientos de angiograf√≠a coronaria (AC) y angioplastia coronaria transluminal percut√°nea (ACTP) en el servicio de hemodinamia del Hospital Universitario San Ignacio a partir del an√°lisis de los valores del Producto Kerma - √Ārea acumulado. Esto permitir√°¬ī la optimizaci√≥n de los procedimientos, a partir de la identificaci√≥n de las posibles situaciones de riesgo en las cuales se pueda reducir la exposici√≥n de los pacientes, sin afectar el procedimiento cl√≠nico. Para realizar la evaluaci√≥n de los VT aplicados al PKA en el paciente, se tom√≥ una muestra de 27 y 15 pacientes para AC y ACTP, respectivamente, que cumpl√≠an caracter√≠sticas est√°ndares, tales como peso aproximado de 75 kg y en un rango de edad entre los 50 y 80 a√Īos. Los VT para el PKA de los procedimientos de AC y ACTP fueron 4,5 y 12,3 Gy¬∑cm2, respectivamente. Adicionalmente, se evalu√≥ la tasa de kerma en la superficie de entrada utilizando un maniqu√≠, obteniendo valores del 23% y 17% de la tolerancia recomendadas para los modos de fluoroscopia alta y normal, respectivamente, sin magnificaci√≥n y para el caso de una magnificaci√≥n de 22 cm los valores son del 56% y 33% de la tolerancia para los modos de fluoroscopia alta y normal, respectivamente.The objective of this work is to apply international protocols of dosimetry in patients undergoing radiology procedures Fluoroscopically guided interventional (FGI) in order to establish typical values (TV) applicable to patients undergoing coronary angiography procedures (CA) and Percutaneous Transluminal Coronary Angioplasty (PTCA) In the service of Hemodynamics of the university Hospital San Ignacio, starting from the analysis of the values of the product Kerma - Area accumulated. This will allow the optimization of procedures, based on the identification of the possible risk situations in which they can reduce the exposure of patients, without affecting the clinical procedure. For the evaluation of the TV applied to the protein kinase inhibitor (PKI) in the patient, a sample of 27 and 15 CA and PTCA patients, respectively, who met standard features, such as approximate weight of 75 kg and in an age range between 50 and 80 years. The TV to the PKI of the procedures of CA and PTCA were 4,5 and 12,3 Gy¬∑cm2, respectively. In addition, we evaluated the rate of kerma in the surface using a dummy, obtaining values of 17% and 23% of the tolerance for the fluoroscopy modes normal and high, respectively, without magnification and, in the case of a magnification of 22 cm values are 56% and 33% of the tolerance for the fluoroscopy modes high and normal, respectively.Mag√≠ster en F√≠sica M√©dicaMaestr√≠

    Horizontal cooling towers: riverine ecosystem services and the fate of thermoelectric heat in the contemporary Northeast US

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    The electricity sector is dependent on rivers to provide ecosystem services that help regulate excess heat, either through provision of water for evaporative cooling or by conveying, diluting and attenuating waste heat inputs. Reliance on these ecosystem services alters flow and temperature regimes, which impact fish habitat and other aquatic ecosystem services. We demonstrate the contemporary (2000‚Äď2010) dependence of the electricity sector on riverine ecosystem services and associated aquatic impacts in the Northeast US, a region with a high density of thermoelectric power plants. We quantify these dynamics using a spatially distributed hydrology and water temperature model (the framework for aquatic modeling in the Earth system), coupled with the thermoelectric power and thermal pollution model. We find that 28.4% of thermoelectric heat production is transferred to rivers, whereas 25.9% is directed to vertical cooling towers. Regionally, only 11.3% of heat transferred to rivers is dissipated to the atmosphere and the rest is delivered to coasts, in part due to the distribution of power plants within the river system. Impacts to the flow regime are minimal, while impacts to the thermal regime include increased river lengths of unsuitable habitats for fish with maximum thermal tolerances of 24.0, 29.0, and 34.0‚ÄȬį C in segments downstream of plants by 0.6%, 9.8%, and 53.9%, respectively. Our analysis highlights the interactions among electricity production, cooling technologies, aquatic impacts, and ecosystem services, and can be used to assess the full costs and tradeoffs of electricity production at regional scales
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