UK PubMed Central (United Kingdom)

The protozoan parasite Trypanosoma cruzi is the etiologic agent of Chagas disease, a neglected tropical infection that affects millions of people in the Americas. Current chemotherapy...Full Text Available

Environmental Research Database

DescriptionRoot-knot nematodes (Meloidogyne spp.) are major nematode pests of most tropical crops, making roots less efficient at withdrawing nutrients and water from soil, sometimes causing the total failure of crops grown by resource-poor farmers in Africa. Nematicides are some of the most toxic products used in crop protection, and are inappropriate or too expensive for use on most crops in Africa and there is an urgent need for new methods of nematode management. The fungus Pochonia chlamydosporia is [continued...

UK PubMed Central (United Kingdom)

Costs of parasitism are commonly measured by comparing the performance of infected groups of individuals to that of uninfected control groups. This measure potentially underestimates the cost of parasitism...Full Text Available

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... By comparing the behavior of individuals tackling the missionaries and cannibals problem to pairs of people solving this problem, we have been ...

UK PubMed Central (United Kingdom)

BackgroundThe hard clam, Mercenaria mercenaria, has been affected by severe mortality episodes associated with the protistan parasite QPX (Quahog Parasite Unknown)...Full Text Available

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BackgroundObtaining single parasite clones is required for many techniques in malaria research. Cloning by limiting dilution using microscopy-based assessment for parasite growth...Full Text Available

Science.gov (United States)

This dissertation evaluates recent proposals to include tropical deforestation into international climate change mitigation strategies. The research ... ...

Science.gov (United States)

Title: Illicit Crops in Tropical America: Deforestation, Landslides, and the Terrestrial Carbon Stocks. Author: Lopez-Rodriguez, Sara R.; Blanco-Libreros, Juan F. ...

Science.gov (United States)

Abstract: The NASA Landsat Pathfinder Humid Tropical Deforestation Project mapped global deforestation for the humid tropics. Data sets from both the TM ...

Science.gov (United States)

... inferences. Thatcher carries the banner for studies of isopod parasites of fishes of the Amazonian region. This fauna ... ...

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BackgroundPlasmodium falciparum morbid and fatal risks are considerably higher in areas supporting parasite prevalence ≥25%, when compared with low transmission...Full Text Available

UK PubMed Central (United Kingdom)

Protective innate immunity to the nematode Strongyloides stercoralis requires eosinophils in the parasite killing process. Experiments were performed to determine if an extract of S....Full Text Available

UK PubMed Central (United Kingdom)

Intestinal parasitic infections have been perceived as a public health problem in Seychelles for decades. A comprehensive strategy to reduce morbidity and, in the long term, transmission of intestinal...Full Text Available

UK PubMed Central (United Kingdom)

Model systems to study the effects of chemicals of environmental concern on bacterial and parasitic diseases as well as the immunosurveillance and destruction of transplantable tumor cells were described...Full Text Available

UK PubMed Central (United Kingdom)

Background and AimsThere has been little previous work on the toughness of the laminae of monocots in tropical lowland rain forest (TLRF) despite the potential importance of greater...Full Text Available

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This article addresses land-cover and land-use dynamics from the perspective of regional science and

British Library Electronic Table of Contents (United Kingdom)

The known metazoa parasite fauna of the invasive round goby Apollonia melanostoma (formerly Neogobius melanostomus) consists of 12 species. The core of the parasite fauna comprises two species: Cryptocotyle concavum and Diplostomum spathaceum; secondary species are absent; satellite species include Cercariae gen. sp. and Ergasilus sieboldi; rare species are Acanthocephalus lucii, Anguillicola crassus, Bothriocephalus sp., Dichelyne minutus, Hysterothylacium aduncum, Pomphorhynchus laevis, Piscicola geometra, and Tylodelphys clavata. Fifty percent of metazoa parasites that occurred in the invasive round goby in the Gulf of Gda?sk (an invasion that was first detected in 1990) are also typically found in the native Gulf of Gda?sk gobiids. The round goby hosts common fish parasite species: C. ...

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... HIV & AIDS (15) I Infectious Diseases (21) Injection Drug Use (7) M Mental Illness (138) Mortality (7) ... Hallucinogens (5) Hashish (2) Heroin (21) I Illegal Drugs (116) Inhalants (12) K Ketamine (1) L LSD ( ...

UK PubMed Central (United Kingdom)

BackgroundPlasmodium falciparum is the most malignant agent of human malaria. It belongs to the taxon Laverania, which includes other ape-infecting Plasmodium...Full Text Available

UK PubMed Central (United Kingdom)

AbstractThree new species of parasitic mites of the genus Neharpyrhynchus Fain (Acariformes,...Full Text Available

UK PubMed Central (United Kingdom)

This Memorandum, after summarizing the life cycle of the different species of human schistosome, reviews the present knowledge of the immunology of schistosomiasis. Each stage of the parasite contains...Full Text Available

UK PubMed Central (United Kingdom)

Haloorganic biocides are widely employed as soil fumigants to combat the destructive action of plant parasitic nematodes and fungi. These substances are dehalogenated by soil organisms, principally...Full Text Available

UK PubMed Central (United Kingdom)

Dengue, a major public health problem throughout subtropical and tropical regions, is an acute infectious disease characterized by biphasic fever, headache, pain in various parts of the body, prostration,...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundMalaria is one of the most important tropical diseases that affects people globally. The influence of environmental conditions in the patterns of temporal distribution...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Abstract Question: How do the diversity, size structure, and spatial pattern of woody species in a temperate (Mediterranean climate) forest compare to temperate and tropical forests? Location: Mixed evergreen coastal forest in the Santa Cruz Mountains, California, USA. Methods: We mapped, tagged, identified, and measured all woody stems (?1 cm diameter) in a 6-ha forest plot, following Center for Tropical Forest Science protocols. We compared patterns to those found in 14 tropical and 12 temperate forest plots. Results: The forest is dominated by Douglas-fir (Pseudotsuga menziesii) and three species of Fagaceae (Quercus agrifolia, Q. parvula var. shrevei, and Lithocarpus densiflorus), and includes 31 woody species and 8180 individuals. Much of the diversity was in small-diameter shrubs,...

UK PubMed Central (United Kingdom)

We have demonstrated that the 80 kDa POP Tc80 (prolyl oligopeptidase of Trypanosoma cruzi) is involved in the process of cell invasion, since specific inhibitors block parasite...Full Text Available

UK PubMed Central (United Kingdom)

Following infection with the protozoan parasite Leishmania major, C57BL/6 mice develop a small lesion that heals spontaneously. Resistance to infection is associated with the development...Full Text Available

International Nuclear Information System (INIS)

EPRI's Steam Generator Strategic Management Project issues an annual report on the progress being made in tackling steam generator problems worldwide, containing a wealth of detailed statistics on the status of operating units and degradation mechanisms encountered. A few highlights are presented from the latest report, issued in October 1993, which covers the period to 31 December 1992. (Author).

Science.gov (United States)

The summertime tropical cyclogenesis rate per unit area in the eastern Pacific ocean is arguably higher than in any other location in the world. Many if not most of these cyclones form from African easterly waves which cross Central America into the Pacific. Of order 25% of these waves intensify into cyclones. A significant fraction of east Pacific tropical cyclones undergoes landfall on the Mexican coast. Those which do not, generally dissipate over cold ocean waters north of the east Pacific intertropical convergence zone, often not far from land. The layer of warm ocean water which supports the development of east Pacific cyclones is unusually shallow and is structured by anticyclonic vortices which form by various processes and propagate slowly to the west. These vortices locally deepen the oceanic mixed layer and support stronger convection than their surroundings, possibly promoting cyclogenesis and cyclone intensification. Cyclones ...

Science.gov (United States)

In three calves experimentally infected with Trypanosoma congolense the amounts of IgG1 and IgG2 were little changed and similar to those of normal animals. IgM increased in amount early in the infection and the amount of the increase appeared related to the parasite burden. The amounts of IgA and IgE were both much decreased and this also appeared related to the numbers of parasites in the blood. There was a decrease in the amounts of total haemolytic complement and complement components C1, C1q and C3 in the infected calves. Furthermore the amounts of properdin fluctuated with the cyclical changes in numbers of T. congolense parasites in the individual calves. No significant change in the amount of C8 was observed. It is considered that activation of both the alternative and the classical complement pathways occurs in trypanosome infected animals but that neither pathway goes to its terminal stages.

Energy Technology Data Exchange (ETDEWEB)

The paper presents cloud structure models for Jupiter's Great Red Spot, Equatorial and North Tropical Zones, North and South Temperate Zones, and North and South Polar Regions. The models are based on images of Jupiter in three methane bands and nearby continuum radiative transfer calculations include multiple scattering and absorption from three aerosol layers. The model results include the transition in the upper-cloud altitude to 3 km lower altitude from the tropical zones to temperate zones and polar regions, a N/S asymmetry in cloud thickness in the tropical and temperature zones, and the presence of aerosols up to about 0.3 bar in the Great Red Spot and Equatorial Zone. It is concluded that polarization data are sensitive to aerosols in and above the upper cloud layer but insensitive to deeper cloud structure.

British Library Electronic Table of Contents (United Kingdom)

The association between invasive and native species varies across spatial scales and is affected by phylogenetic relatedness, but these issues have rarely been addressed in aquatic ecosystems. In this study, we used a non-native, highly invasive species of Poaceae (tropical signalgrass) to test the hypotheses that (i) tropical signalgrass success correlates negatively with success of most native species of macrophytes at fine spatial scales, but its success correlates positively or at random with natives at coarse spatial scales, and that (ii) tropical signalgrass is less associated with native species belonging to the family Poaceae than with species belonging to other families (Darwin?s naturalization hypothesis). We used a dataset obtained at fine (0.25?m2) and coarse (ca. 1,000?m2) sca...

UK PubMed Central (United Kingdom)

BackgroundThe pathogenicity of Plasmodium falciparum is in part due to the ability of the parasitized red blood cell (pRBC) to adhere to intra-vascular host cell...Full Text Available

UK PubMed Central (United Kingdom)

Cysticercosis is an infection with larval cysts of the cestode Taenia solium. Through pathways that are incompletely understood, dying parasites initiate a granulomatous reaction that,...Full Text Available

Science.gov (United States)

Resistance against anthelmintics is widespread, particularly in parasitic nematode populations of small ruminants. Several new techniques or supplements have been developed or are under investigation. Biological control (BC) is one of these new methods. The net-trapping predacious fungus Duddingtonia flagrans produces thick walled resting spores, chlamydospores, which are able to survive passage through the gastrointestinal tract of cattle, horses, sheep and pigs. Under Danish climatic conditions it has been shown that the number of parasite larvae on pasture and the worm burden of the grazing animals is significantly reduced when animals are fed spores during the initial 2-3 months of the grazing season. Work with D. flagrans in France, Australia, USA, and Mexico has confirmed the strong BC potential of this fungus. Today much work is going into development of suitable delivery systems for grazing livestock worldwide. Ultimately, BC should be ...

UK PubMed Central (United Kingdom)

Neurocysticercosis (NCC) is the most common parasitic infestation of the central nervous system. Most cases of NCC are to related and/or associated with inflammation within the cerebral parenchyma....Full Text Available

UK PubMed Central (United Kingdom)

BackgroundArtemisinin-based combination therapy, currently considered the therapy of choice for uncomplicated Plasmodium falciparum malaria in endemic countries,...Full Text Available

UK PubMed Central (United Kingdom)

The effectiveness of chemotherapy in human schistosomiasis varies from one area to another, and limited data from experimentally infected animals suggest inherent differences in the susceptibility...Full Text Available

UK PubMed Central (United Kingdom)

Fibrogenesis is a common feature of many diseases where there is severe insult to the liver. The hepatic stellate cell trans-differentiation into a myofibroblast has been identified as an important...Full Text Available

UK PubMed Central (United Kingdom)

Trypanothione reductase (TryR) is a key enzyme involved in the oxidative stress management of the Trypanosoma and Leishmania parasites, which helps to maintain an intracellular reducing environment...Full Text Available

UK PubMed Central (United Kingdom)

Cutaneous leishmaniasis (CL) is a parasitic disease characterized by single or multiple ulcerations. Secondary bacterial infections are one of the complications that can increase the tissue destruction...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundA microsporidian was previously reported to infect the crustacean parasite, Lepeophtheirus salmonis (Krøyer, 1837) (Copepoda, Caligidae), on farmed...Full Text Available

UK PubMed Central (United Kingdom)

The worldwide decline in honeybee colonies during the past 50 years has often been linked to the spread of the parasitic mite Varroa destructor and its interaction with certain honeybee...Full Text Available

UK PubMed Central (United Kingdom)

The extensive diversity of Plasmodium falciparum antigens is a major obstacle to a broadly effective malaria vaccine but population genetics has rarely been used to guide vaccine design....Full Text Available

UK PubMed Central (United Kingdom)

In world Helminthes infections are the most widespread of all the infections in humans. The morbidity due to parasitic diseases has been increasing in our population. The gastrointestinal helminthes...Full Text Available

UK PubMed Central (United Kingdom)

Chagas disease, caused by infection with Trypanosoma cruzi, is an important cause of cardiovascular disease. It is increasingly clear that parasite-derived prostaglandins potently modulate...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundCerebral malaria (CM) is a neurological syndrome that includes coma and seizures following malaria parasite infection. The pathophysiology is not fully understood and cannot...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Summary DNA topoisomerases are the key enzymes involved in carrying out high precision DNA transactions inside the cells. However, they are detrimental to the cell when a wide variety of topoisomerase-targeted drugs generate cytotoxic lesions by trapping the enzymes in covalent complexes on the DNA. The discovery of unusual heterodimeric topoisomerase I in kinetoplastid family added a new twist in topoisomerase research related to evolution, functional conservation and their preferential sensitivity to Camptothecin. On the other hand, structural and mechanistic studies on kinetoplastid topoisomerase II delineate some distinguishing features that differentiate the parasitic enzyme from its prokaryotic and eukaryotic counterparts. This review summarizes the recent advances in research in kin...

UK PubMed Central (United Kingdom)

Tinea nigra is a superficial mycosis caused by Hortaea werneckii. It is an infrequent asymptomatic infection that affects human palms and soles, and is mostly observed in tropical...Full Text Available

UK PubMed Central (United Kingdom)

It has been suggested that individual recognition based on song may be constrained by repertoire size in songbirds with very large song repertoires. This hypothesis has been difficult to test...Full Text Available

UK PubMed Central (United Kingdom)

The impacts of climate change on crop productivity are often assessed using simulations from a numerical climate model as an input to a crop simulation model. The precision of these predictions reflects...Full Text Available

Science.gov (United States)

Climate Observations Joint Air-Sea Monsoon Investigation: JASMINE Nauru '99 NTAS PACS SHEBA STRATUS VOCALS WHOTS Data Cruises Tropical Eastern Pacific Synthesis The Research...

Energy Technology Data Exchange (ETDEWEB)

Adenosine triphosphate (ATP) is an indicator of living biomass in marine particulates. This report details the method used by Lawrence Berkeley Laboratory to analyze particulate ATP in samples taken from oligotrophic, tropical ocean waters. It represents a synthesis of previously published methods.

UK PubMed Central (United Kingdom)

BackgroundDengue fever is a mosquito-borne illness that places significant burden on tropical developing countries with unplanned urbanization. A surveillance system using Google...Full Text Available

Environmental Research Database

ObjectivesThe specific objectives of the research are to: 1. Determine the concentrations of N2O, NO and NO2 in tropical coastal waters in relation to nutrients and salinities. 2. Determine, with excess nitrate present, the potential for nitrate reduction and denitrification in sediments along tropical estuaries, and whether NO, NO2, N2O, N2 or NH4+ are significant products. 3. Establish the balance between denitrification, nitrate ammonification and anammox in tropical estuarine sediments, relative to [continued...]DescriptionThe coastal zone is extremely important in the biogeochemical processes which control the natural cycle of elements of the Earth. In particular, the coastal zone contributes significantly to the nitrogen cycle, removing nitrogen washed in from the land by rivers and so reducing its fertilizing impact on the coastal seas. However, these removal processes, driven by microorganisms, also contribute to ...

Environmental Research Database

DescriptionChamber studies have shown that biogenic organic compounds, including isoprene, are capable of producing secondary organic aerosol in significant quantities. This is surprising as isoprene and its photo-oxidation products have relatively high vapour pressures. However, it is very important as isoprene has the largest global emissions flux of any biogenic hydrocarbon, most of which is in the tropics. Despite this, secondary organic aerosol has been poorly studied in tropical regions with only [continued...

International Nuclear Information System (INIS)

This is a preliminary study on the sound absorption properties of two tropical hardwoods, Light Red Meranti and Ramin, and their wood-polymer composites. Sound absorption is measured using a standing wave apparatus. The samples are of one thickness (7 mm) and cut longitudinally. Wood-polymer composites are made by impregnating the samples with methyl methacrylate which is polymerized in situ through #gamma#-irradiation. Both woods and their composites are better sound absorbers at higher sound frequencies. With partial impregnation, the absorption coefficients are improved upon particularly in the region between 1-3 kHz. (author).

International Nuclear Information System (INIS)

The compressive and bending strengths of a local tropical wood (Kapur-Dryobalanop sp.) were improved significantly by suitable impregnation of polymeric monomers (methylmethacrylate, methylmethacrylate - 5% dioxane and vinyl acetate) into the wood cellular structure and subsequent irradiation to form a wood-polymer composite. Statistical analysis revealed a linear relationship between increase in the strengths and the percentage of polymer impregnated. Fractographic analysis of the impact fractured surfaces under the scanning electron microscope showed the nature of the wood-polymer interface, which could account for the increase in the compressive and bending strengths. (author).

CERN Document Server

In source coding, either with or without side information at the decoder, the ultimate performance can be achieved by means of random binning. Structured binning into cosets of performing channel codes has been successfully employed in practical applications. In this letter it is formally shown that various convolutional- and turbo-syndrome decoding algorithms proposed in literature lead in fact to the same estimate. An equivalent implementation is also delineated by directly tackling syndrome decoding as a maximum a posteriori probability problem and solving it by means of iterative message-passing. This solution takes advantage of the exact same structures and algorithms used by the conventional channel decoder for the code according to which the syndrome is formed.

International Nuclear Information System (INIS)

In this paper the authors describe the design and development of an advanced NDA workstation, which fits into an integrated data evaluation scheme for safeguards. This kind of instrument must be sort of an intelligent assistant to the inspection procedure, be able to generate as correct as possible measurements, guide the inspector throughout the procedure, and report descriptive data to the data evaluation system. The problem of improving the quality of the measurement is tackled using a simple expert system, which should convey in the instrument some of the physicist knowledge. The authors describe the hardware and software resources which were included in their design to reach the intended goal. A prototype of the machine has been built, and a preliminary software for Plutonium Isotopic Composition is under development.

Energy Technology Data Exchange (ETDEWEB)

Malfunctions in machinery are often sources of reduced productivity and increased maintenance costs in various industrial applications. For this reason, machine condition monitoring is being pursued to recognise incipient faults. In this paper, the fault diagnostic problem is tackled within a neuro-fuzzy approach to pattern classification. Besides the primary purpose of a high rate of correct classification, the proposed neuro-fuzzy approach also aims at obtaining an easily interpretable classification model. The efficiency of the approach is verified with respect to a literature problem and then applied to a case of motor bearing fault classification.

Science.gov (United States)

Throughout much of the 1980s, deforestation in Brazil eliminated more than 15,000 square kilometers (9000 square miles) per year. That pace has only increased through the 90s and into the 21st century. Brazil is also home to more than a quarter of Earths tropical forests. Considering that the band of lush green that circles the globe through many equatorial nations is fundamental to the overall health of the whole planets environment, careful monitoring of forest health in the tropics is essential. Tropical forests act as major carbon sinks, places where ambient carbon dioxide in the atmosphere can be absorbed by growing things and sequestered for years. Definitive evidence shows that excess carbon dioxide can contribute to the greenhouse effect and speed global warming. Similarly, tropical forests also act as a primary producer of oxygen. In the respiration process that absorbs gaseous carbon dioxide, ...

International Nuclear Information System (INIS)

In a series of experiments carried out on young and adult rabbits the effect of isocaloric low protein diets containing 4% or 8% protein compared with a diet containing 21% protein on Obeliscoides cuniculi infection was studied. The pathogenesis, resistance and local immunity were assessed after single infections with 10,000 larvae or reinfection with 5000 larvae. Live weight gain was reduced in young and adult rabbits fed the low protein diets, but the establishment of parasites was not substantially influenced by protein deprivation. However, development of worms in the histotrophic phase and parasite fecundity were impaired in association with the low protein diet. Moreover, mild anaemia as well as changes in the mucosal immune response as a result of infection were related to the level of dietary protein. (author). 30 refs, 6 figs, 5 tabs.

British Library Electronic Table of Contents (United Kingdom)

Invasive weeds have threatened the integrity of ecosystems throughout the world. They affect not only the species diversity of native areas but also their biological integrity. In India, a number of invasive exotic weeds have been reported but some viz. Parthenium hysterophorus, Lantana camara and Ageratum conyzoides, especially those from tropical America are troublesome and have caused adverse ecological, economic and social impact. These weeds can be seen growing in different landscapes but are luxuriantly localized in unattended forests and cultivated areas. Parthenium hysterophorus (Asteraceae, commonly known as congress grass) is perhaps the most troublesome and noxious weed of urban and rural India. Besides rapidly colonizing areas replacing the native vegetation, it is also known t...

British Library Electronic Table of Contents (United Kingdom)

Leaf litterfall, litter decomposition and nutrient return through litterfall of three dominant species, i.e. Quercus serrata, Schima wallichi and Lithocarpus dealbata were studied in different months throughout the year to assess the input and release of nutrient in the forest soil of a sub-tropical mixed oak forest of Manipur, northeastern India. Oaks in northeastern region of India are economically important species for the production of Tasar silk. The monthly litterfall ranged from 25.6 g?m?2 (July) to 198.0 g?m?2 (February) and annual litterfall was 1093.8g?m?2 in the forest site. At initial month (on November 3), the concentrations of N and C were the highest in L. dealbata, followed by Q. serrata and lowest in S. wallichi, whereas lignin and cellulose concentrations at initial month...

British Library Electronic Table of Contents (United Kingdom)

ABSTRACT Drought is an important seedling mortality agent in dry and moist tropical forests, and more severe and frequent droughts are predicted in the future. The effect of drought on leaf gas exchange and seedling survival was tested in a dry-down experiment with four tree species from dry and moist forests in Bolivia. Seedlings were droughted and wilting stage and gas exchange were monitored. Drought led to a gradual reduction of photosynthesis and stomatal conductance over time, whereas respiration and photosynthetic water-use efficiency initially increased with drought and then declined. Seedlings gradually went through the different wilting stages, until they eventually died, but the trajectory differed for the four species. The strong relationship between wilting stage and photosynt...

UK PubMed Central (United Kingdom)

Among important candidates for babesial vaccines are apical complex proteins, including rhoptry-associated protein 1 (RAP-1) from Babesia bovis and B. bigemina, which...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundThe present study evaluated the SD Bioline Malaria Ag 05FK40 (SDFK40), a three-band RDT detecting Plasmodium falciparum-specific parasite lactate dehydrogenase...Full Text Available

International Nuclear Information System (INIS)

Power devices such as MOSFETSs and IGBTs, include parasitic structures that can give rise to destructive failures such as breakdown and latch-up. To determine a suitable strategy for device radiation hardening, simulation software like MEDICI-2D can be used to model the effects of technological modifications and device parameters that are difficult to measure experimentally. (authors).

Wastenet

...htm Waste Framework Directive 75/442/EEC (amended by Directive 91/156/EEC) and Waste Management Planning http://ec.europa.eu/environment/waste/plans/index.htm Selected EC commissioned/supported projects including LCA IPP Pilot Product exercise on mobile phones and on tropical garden furniture http://ec.europa.eu/environment/ipp/pilot.htm \\

UK PubMed Central (United Kingdom)

Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and other diseases....Full Text Available

International Nuclear Information System (INIS)

The use of WPC as an important insulating material is studied by determining its dielectric constant. The variation of dielectric constant with moisture content is also investigated. Preliminary results show that all untreated woods studied have a higher dielectric constant than their polymer composites with the exception of Kapur and Keruing. It is therefore postulated that the presence of polymers has led to a decrease in the number of polarizable units. Such a material may be useful commercially. (author).

International Nuclear Information System (INIS)

An experimentalist looking for free tachyons is faced with the following two related problems: A) How does a tachyon interact with bradyonic matter. Is it an object more or less localized in space-time. B) How should a (bradyonic) detector for tachyons look. To answer B) you should necessarily know something about A). But a theory which provides sufficient information doesn't exist at the moment. Therefore it is necessary to make some simple assumption to tackle problem B). In the second part of this contribution two possibilities of tachyon detectors are proposed assuming that a free charged tachyon (if it exists) exhibits normal electromagnetic interaction with bradyonic matter. Another possibility to look for tachyons produced in high energy reactions of bradyons is the missing mass method using the fact that the four-momentum of a collection of particles can be spacelike if at least one tachyon is present. Such experiments have been undertaken with negative ...

International Nuclear Information System (INIS)

During their catalytic cycle, proteins involved in biological signal transduction undergo unexpectedly large conformational changes, which are at the core of their biological functioning. Until now it has been extremely difficult to obtain experimental insight into the nature of these conformational changes. Mathematical modeling and time-resolved X-ray crystallography have resulted in probable routes along which these conformational changes may take place, but so far this fundamental biological phenomenon has hardly been tackled experimentally. Here, we report on an attempt to observe structural changes in Photoactive Yellow Protein with time-resolved small-angle neutron scattering using diffractometer D22 at the high-flux reactor of the Institut Laue-Langevin, Grenoble, France

International Nuclear Information System (INIS)

Multiple Reggeon exchange supplies subleading logarithms that may be used to restore unitarity to the Low-Nussinov Pomeron, provided it can be proven that the sum of Feynman diagrams to all orders gives rise to such multiple Regge exchanges. This question cannot be easily tackled in the usual way except for very low-order diagrams, on account of delicate cancellations present in the sum which necessitate individual Feynman diagrams to be computed to subleading orders. Moreover, it is not clear that sums of high-order Feynman diagrams with complicated crisscrossing of lines can lead to factorization implied by the multi-Regge scenario. Both of these difficulties can be overcome by using the recently developed non-Abelian cut diagrams. We are then able to show that the sum of s-channel-ladder diagrams to all orders does lead to such multiple Reggeon exchanges. copyright 1997 The American Physical Society.

CERN Document Server

A transformation monoid on a set Omega is called synchronizing if it contains an element of rank 1 (that is, mapping the whole of Omega to a single point). In this paper, I tackle the question: given n and k, what is the probability that the submonoid of the full transformation monoid T_n generated by k random transformations is synchronizing? This question is analogous to Dixon's Theorem that two random permutations generate the symmetric or alternating group with high probability. Following the technique of Dixon's theorem, we need to analyse the maximal non-synchronizing submonoids of T_n. I develop a very close connection between transformation monoids and graphs, from which we obtain a description of non-synchronizing monoids as endomorphism monoids of graphs satisfying some very strong conditions. However, counting such graphs, and dealing with the intersections of their endomorphism monoids, seems difficult.

Energy Technology Data Exchange (ETDEWEB)

In field O{sub 3}-enrichment experiments increased herbivore densities have been reported, which could be due to negatively affected host location behavior of natural enemies. We addressed the impact of doubling background O{sub 3} on the host location of the parasitoid Cotesia plutellae by conducting 24-h trials in an open-air O{sub 3}-fumigation system during two consecutive years. Two circles (radii 1.40 and 4.00 m) of Plutella xylostella-infested potted cabbage plants were placed in the O{sub 3} and ambient plots. Female wasps were released into each plot from the center, and observed 5 times over a 24-h period to assess their host location capability. Thereafter, plants were kept in laboratory conditions until larvae pupation to determine parasitism rates. No significant differences were detected between ambient and O{sub 3}-enriched environments either in the number of wasps found in the field, or in the percentages of parasitized larvae. ...

Science.gov (United States)

In previous molecular phylogenetic analyses of the freshwater mussel family Unionidae (Bivalvia: Unionoida), the Afrotropical genus Coelatura had been recovered in various positions, generally indicating a paraphyletic Unionidae. However that result was typically poorly supported and in conflict with morphology-based analyses. We set out to test the phylogenetic position of Coelatura by sampling tropical lineages omitted from previous studies. Forty-one partial 28S nuclear rDNA and partial COI mtDNA sequences (1130 total aligned nucleotides) were analyzed separately and in combination under both maximum parsimony and likelihood, as well as Bayesian inference. There was significant phylogenetic incongruence between the character sets (partition homogeneity test, p<0.01), but a novel heuristic for comparing bootstrap values among character sets analyzed separately and in combination illustrated that the observed conflict was due to homoplasy rather than separate ...

Science.gov (United States)

PCR detection of genetic material of the parasites present in faeces may be an alternative for microscopic and serological tests routinely used for diagnosing parasitic enteral infections. However, small amount of target DNA combined with low efficiency of total DNA extraction, and presence of PCR inhibitors in the samples to be amplified, may cause false negative detection results. The aim of this work was to evaluate the impact of DNA isolation procedure used on the amplification of DNA fragments from the genomes of protozoan Cryptosporidium parvum and the nematode Trichinella spiralis. Two methods based on different principles of biological material lysis were evaluated; NucliSENS miniMAG employing simultaneously applied chemical lysis and mechanical disruption or mechanical disruption followed by enzymatic lysis in case of QIAamp DNA Stool Mini Kit. Both of the analyzed systems for nucleic acids purification allowed isolation of DNA from ...

International Nuclear Information System (INIS)

The thermal properties of five types of radiation-induced wood-polymer composites based on a tropical hardwood, rubberwood (Hevea braziliensis), was studied by oxygen index measurement, differential thermal analysis (DTA) and thermogravimetry (TG). The DTA and TG curves of composites were different from those of rubberwood, which can be attributed to the presence of the incorporated polymers. Of the five composites, the one impregnated with bis(2-chloroethyl)vinyl phosphonate reduced the initial temperature of decomposition, increased the peak temperatures of exothermic reactions, and increased the char yield. Comparison with physical blends of rubberwood and the corresponding polymer provided some evidence of chemical interaction of wood and polymer in some of the composites. (author).

Science.gov (United States)

EXPLORES! (EXPloring and Learning the Operations and Resources of Environmental Satellites!) is an educational outreach program developed at Florida State University with the intention of introducing weather satellite receiving technology into the primary and secondary school classrooms. The website furnishes real time high resolution imagery and tropical updates. Visitors can find historical accounts of the civilian weather satellites launched by the United States. Educators can discover kindergarten through twelfth grade resources and curriculum. Users can learn how to become a part of the WXSAT-L community email list where weather satellite professionals, amateurs, and hobbyists converse about scientific, tracking, launching, and operations information.

Energy Technology Data Exchange (ETDEWEB)

Several wood samples collected from Dorslandboom, a large iconic African baobab (Adansonia digitata L.) from Namibia, were investigated by AMS radiocarbon dating subsequent to pretreatment and, alternatively, without pretreatment. The comparative statistical evaluation of results showed that there were no significant differences between fraction modern values and radiocarbon dates of the samples analyzed after pretreatment and without pretreatment, respectively. The radiocarbon date of the oldest sample was 993 +- 20 BP. Dating results also revealed that Dorslandboom is a multi-generation tree, with several stems showing different ages.

International Nuclear Information System (INIS)

Global climate policy initiatives are now being proposed to compensate tropical forest nations for reducing carbon emissions from deforestation and forest degradation (REDD). These proposals have the potential to include developing countries more actively in international greenhouse gas mitigation and to address a substantial share of the world's emissions which come from tropical deforestation. For such a policy to be viable it must have a credible benchmark against which emissions reduction can be calculated. This benchmark, sometimes termed a baseline or reference emissions scenario, can be based directly on historical emissions or can use historical emissions as input for business as usual projections. Here, we review existing data and methods that could be used to measure historical deforestation and forest degradation reference scenarios including FAO (Food and Agricultural Organization of the United Nations) national statistics and ...

Energy Technology Data Exchange (ETDEWEB)

The present study treats only the collective risk of ex-utero leukaemia associated with the routine releases of the nuclear industrial installations of the North Cotentin (0.0009 cases over the considered period) the uncertainty on the contribution to the collective risk of the incidents and the accidents of the nuclear installations (notably the drilling of the pipe of release in sea arisen in 1979-1980 and the fire of the waste silo on January 6. 1981, for the reprocessing plant of La Hague has not been considered. Only 45% of the risk are taken into account by the study. Every calculated value remains very inferior to the number of leukemia cases observed (4 cases observed for two expected cases) and to the risk of radioinduced leukemia any merged exposure sources, that is to say 0.84 cases. It appears thus not very probable that the nuclear installations of the North - Cotentin can explain the tendency to the excess of observed leukaemia. The limits of the study become attached for ...

Energy Technology Data Exchange (ETDEWEB)

Rehabilitation of the abandoned uranium mining areas in Saxonia and Thuringia is a task posing also legal problems. The radiation protection laws of the former GDR continued to be effective to a great extent and proved to be a legal basis not ``perfect`` in formal terms, but suitably efficient in practice to tackle the manifold problems encountered in the land reclamation and waste disposal work. Originally intended to serve as a legal interim regime awaiting amendment at a later date, the body of laws available for the task proved to be a sufficient basis. (orig./HP) [Deutsch] Das fortgeltende Strahlenschutzrecht der frueheren DDR hat sich zwar nicht als formal `perfektes`, in der Sache aber strahlenschutzgerechtes und praktikables Instrument zur Loesung der anstehenden Sanierungsaufgaben erwiesen. Bei seiner Beurteilung darf nicht ausser Acht gelassen werden, dass die Ueberleitung dieses Rechts seinerzeit aus der Not eines kurzfristigen Regelungsbedearfs geboren ...

CERN Document Server

Email Retrieval task has recently taken much attention to help the user retrieve the email(s) related to the submitted query. Up to our knowledge, existing email retrieval ranking approaches sort the retrieved emails based on some heuristic rules, which are either search clues or some predefined user criteria rooted in email fields. Unfortunately, the user usually does not know the effective rule that acquires best ranking related to his query. This paper presents a new email retrieval ranking approach to tackle this problem. It ranks the retrieved emails based on a scoring function that depends on crucial email fields, namely subject, content, and sender. The paper also proposes an architecture to allow every user in a network/group of users to be able, if permissible, to know the most important network senders who are interested in his submitted query words. The experimental evaluation on Enron corpus prove that our approach outperforms known email retrieval ...

British Library Electronic Table of Contents (United Kingdom)

The mature spermatozoon of Cricocephalus albus is filiform, tapered at both ends and shows the following features: 2 axonemes of different lengths presenting the 9+''1'' trepaxonematan pattern, 2 bundles of parallel cortical microtubules, a mitochondrion and a nucleus. Nevertheless, the particularity of the spermatozoon of C. albus is its anterior extremity with an apical electron-dense material associated with extramembranar ornamentation, a cytoplasmic dorsolateral expansion and spine-like bodies. To our knowledge, such an anterior extremity of the spermatozoon has not previously been described from a species of the superfamily Pronocephaloidea. Our study provides new data on the mature gamete of C. albus in order to improve our understanding of the pronocephaloidean phylogenetic relatio...

British Library Electronic Table of Contents (United Kingdom)

The isopod parasite Ceratothoa oestroides becomes hard to eradicate in intensive fish rearing systems and in addition to causing weight loss in adult fish it causes mortalities in larval and juveniles stages of sea bass and sea bream. Faced with the fast emergence of this infection in Adriatic finfish facilities, an effective compound had to be tested for bath treatment. Ivermectin was chosen for this purpose on the basis of extensive practice in northern European countries which used ivermectin administered in food with good results in treatment of Lepeophtheirus sp. and Caligus sp. infections. For determination of toxicity of ivermectin, a short-term toxicity bioassay on 40-day-old sea bream, Sparus aurata, L., was conducted, following FAO and UNEP procedures for methodology in aquatic t...

British Library Electronic Table of Contents (United Kingdom)

Parthenogenesis-inducing (PI) Wolbachia belong to a class of intracellular symbionts that distort the offspring sex ratio of their hosts toward a female bias. In many PI Wolbachia-infected species sex ratio distortion has reached its ultimate expression-fixation of infection and all-female populations. This is only possible with thelytokous PI symbionts as they provide an alternative form of reproduction and remove the requirement for males and sexual reproduction. Many populations fixed for PI Wolbachia infection have lost the ability to reproduce sexually, even when cured of the infection. We examine one such population in the species Trichogramma pretiosum. Through a series of backcrossing experiments with an uninfected Trichogramma pretiosum population we were able to show that the gen...

British Library Electronic Table of Contents (United Kingdom)

Commercial vineyards in southern Spain were surveyed and sampled during October to December 2004 to determine the extent to which common weeds present were suitable hosts of root-knot nematodes infesting soils of those vineyards. Seven weed species commonly growing in grapevine soils in southern Spain were found infected by either Meloidogyne incognita or M. javanica: Amaranthus retroflexus (redroot pigweed), Anchusa azurea (ox-tongue), Chenopodium album (goosefoot), Erodium moschatum (musk stork?s bill), Malva rotundifolia (low mallow), Sinapis alba (white mustard), and Solanum nigrum (black nightshade). The host suitability of the weeds to root-knot nematodes was evaluated on the basis of root galling severity and nematode population densities in soil and roots. Also, the host?parasite r...

International Nuclear Information System (INIS)

The magnicon is a highly attractive candidate to be the RF source for a future multi-Tev linear collider. Physical models and computer codes have been developed which can provide start-to-end self-consistent simulations of a magnicon, including precise simulations of the high-convergence electron gun, RF-system, magnetic system, and beam collector. The 3-D beam dynamics simulations include realistic fields, finite beam size and transverse space charge effects. The codes allow one to provide steady-state simulations of the entire tube, so as to evaluate transient process of magnicon excitation, parasitic mode self-excitation, stability analysis, and tolerance analysis. The results of the simulations are found to be in good agreement with magnicon experiments. A brief description of the physical models and simulation codes employed will be given.

British Library Electronic Table of Contents (United Kingdom)

European sea bass (Dicentrarchus labrax L.) is a marine species of great economic importance, particularly in Mediterranean aquaculture. However, numerous pathogenic viruses, bacteria, fungi and parasites affect the species, causing various infectious diseases and thereby leading to the most heavy losses in aquaculture production of sea bass. In this respect, knowledge on molecular and genetic mechanisms of resistance to pathogens and specific features of immune response against various infectious agents should greatly benefit the development of effective vaccines and proper vaccination strategies in marker-assisted selection of fish resistant to a range of infections. To date, genetic knowledge on sea bass immune regulatory genes responsible for resistance to pathogens is relatively poor ...

Science.gov (United States)

The United States deployed 118 military working dogs (MWDs) to the Persian Gulf theater during Operations Desert Shield and Desert Storm. This study is a retrospective descriptive study of medical records of these deployed dogs, with the objective to determine whether there were infectious or parasitic diseases with a zoonotic potential in a sentinel population of MWDs that may be of concern to Persian Gulf veterans. Fifty-one percent of visits to veterinary treatment facilities during deployment were for illness or injury. Potential zoonotic conditions accounted for 21% of the total visits, 41% of the "sick-call" visits, and 63% of presentations for illness to veterinary treatment facilities. This study did not determine whether the diseases treated were transmitted between MWDs and the troops. Although the etiologic agents were not determined in these cases, no evidence was found supporting new or reemerging illnesses in this population of dogs. PMID:11272705

International Nuclear Information System (INIS)

Among the numerous free-living amoebae (FLA) of soil and water habitats, certain species belonging to two genera Acanthamoeba and Naegleria are facultative parasites of man.They cause disease called primary amoebic meningoencephalitis where history of contact with water was recorded in most of the cases especially with Naegleria species. The present work aimed to search for presence of free-living amoebae in the water and trials for its control by Ultraviolet-radiation (UV-radiation). Samples from different water sources were examined for the presence of free-living amoebae. These samples were cultured on non-nutrient agar streaked with bacteria. Amoebae were detected and identified by means of their morphological characters. Twelve positive cases of one hundred and twenty examined samples could be detected. The positive samples were exposed to different doses of UV-radiation for different times.

CERN Document Server

Luminosity-driven channeling extraction has been observed for the first time in a 900 GeV study at the Fermilab Tevatron. This experiment, Fermilab E853, demonstrated that useful TeV level beams can be extracted from a superconducting accelerator during high luminosity collider operations without unduly affecting the background at the collider detectors. Multi-turn extraction was found to increase significantly the efficiency of the process. The beam extraction efficiency was about 25%. Studies of time dependent effects found that the turn-to-turn structure was governed mainly by accelerator beam dynamics. An investigation of a pre-scatterer using the accelerator flying wire system showed that a fiber could produce a significant extracted flux, consistent with expectations. Based on these results, it is feasible to construct a parasitic 5-10 MHz proton beam from the Tevatron collider.

British Library Electronic Table of Contents (United Kingdom)

The present study describes pathologic findings and immunohistochemical diagnosis of canine visceral leishmaniasis (CVL) in 22 dogs who died naturally in the Aegean region of Turkey. At necropsy, lymphadenomegaly, hepatosplenomegaly, hepatic, and nephrosclerotic lesions were conspicuous. Histopathologically, chronic inflammatory reactions of the spleen, lymph nodes, bone marrow, liver, and skin were marked findings. Cytological and histological examinations showed macrophages loaded with Leishmania amastigotes in these organs. Immunohistochemistry revealed that immunolabeling of amastigotes and/or parasite antigen, especially in the lymph nodes, spleen, bone marrow, liver, and skin, and occasionally, in the kidneys, intestines and lungs. Our laboratory results showed that immunohistochemis...

Science.gov (United States)

Throughout much of the 1980s, deforestation in Brazil eliminated more than 15,000 square kilometers (9000 square miles) of forest per year. Data gathered by several satellites in the Landsat series of spacecraft shows enormous tracts of forest disappearing in Rondonia, Brazil from 1975 through 2001. The human phenomenon of deforestation starts, especially in the dense tropical forests of Brazil, when systematic cutting of a road opens new territory to potential deforestation by penetrating into new areas. Clearing of vegetation along the sides of those roads then tends to fan out to create a pattern akin to a fish skeleton. As new paths appear in the woods, more areas become vulnerable. Finally, the spaces between the skeletal bones fall to defoliation.

British Library Electronic Table of Contents (United Kingdom)

Phytoplankton community composition, density, and succession were studied in tropical commercial ponds with euryhaline tiger shrimp (Penaeus monodon Fabricius) using green-water technology at two different stocking densities [T1 10 post-larvae (PL) m?2 and T2 15 PL m?2] in one grow-out season (May?October 2005) in Leganes, Iloilo, Philippines. Weekly qualitative and quantitative analyses of phytoplankton were done along with physicochemical analyses of the pond waters. A total of 103 taxa belonging to nine different algal classes were observed. Of these classes, the Chlorophyceae, Cyanophyceae and Bacillariophyceae constituted the great bulk of the phytoplankton population. The two treatments did not show any significant differences in the growth pattern of phytoplankton over time and in t...

Energy Technology Data Exchange (ETDEWEB)

A section of the northern margin of the Guineo-Congolian rain forest of the Central African Republic is studied to determine to what extent deforestation is evolving. Three sites are presented to highlight the diversity in local environmental settings at the northern margin of the closed equatorial rain forest: the contiguous equatorial rain forest, the boundary between the closed rain forest and the grasslands, and a predominantly secondary grassland environment. Proven image processing procedures for determining land cover and vegetation vigor were applied to Landsat MSS data to determine land cover characteristics and identify alterations in land cover that indicate potentially degraded forest environments. Land cover was independently assessed using spectral signatures determined from a statistical clustering routine. The images presented and image analyses contribute insights and information to an ongoing effort to determine more reliable data on the status of global ...

British Library Electronic Table of Contents (United Kingdom)

Over 300 delegates participated in this scientific meeting to celebrate the career of the late Professor Tony Hart, who was Head of Department of Medical Microbiology, University of Liverpool, from 1986 until his death in September 2007. The meeting, which was opened by Professor James Stewart (Head, School of Infection and Host Defence, University of Liverpool) and closed by Professor Bernard Brabin (Head of the Child Health Group, Liverpool School of Tropical Medicine), captured some of the major elements that distinguished Tony Harts remarkable career. These included: broad research interests spanning both human and veterinary medicine; the ability to conduct both clinical and basic science research with equal skill and vigour; and his phenomenal mentorship of postgraduate students. Eac...

International Nuclear Information System (INIS)

In order to quantify the biomass burning emissions, the main atmospheric pollution source of tropical and subtropical regions, we carried out the analysis of ashes that are also formed during these fires. To this end, we developed analytical methods to characterize the composition of savannah grass burning ashes by using X-ray fluorescence for mineral elements and microanalysis for C, H, O and N. Samples used in this work have been collected during laboratory combustion experiments, with chemically well-defined natural savannah grasses from Ivory Coasts and South Africa. The reproducibility and efficiency of different developed procedures have been studies. The analytical relative precision is generally better than 5%. This development has allowed to establish, for the first time, the global mass balance of ashes resulting from savannah grass burning. (authors). 16 refs., 3 figs., 8 tabs.

British Library Electronic Table of Contents (United Kingdom)

Often ecologists and natural resource managers can easily access data on invasive species occurrence across a region. Yet, collecting species abundance data over a large area is arguably more important for decision making, but inherently costly, so methods which can provide robust information at low-cost are particularly valuable. Studies of species distribution often use occurrence data to build models of the environmental niche. Environmental suitability derived from such models may be used to predict the potential distributions of species. The ability of such models to predict spatial patterns in abundance have recently been demonstrated. Here we tested the relationship of environmental suitability with local abundance of an aquatic invasive species, olive hymenachne (Hymenachne amplexi...

British Library Electronic Table of Contents (United Kingdom)

Abstract Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of - 21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of - 53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-trop...

British Library Electronic Table of Contents (United Kingdom)

ABSTRACT We present evidence that differences in soil seedbank persistence among pioneer plants in the cloud forest of Monteverde, Costa Rica, are influenced by differences in seed chemical defense. We used extracted seed chemicals from Bocconia frutescens (Papaveraceae), Guettarda poasana (Rubiaceae), Phytolacca rivinoides (Phytolaccaceae), Urera elata (Urticaceae), Cecropia polyphlebia (Cecropiaceae), and Witheringia meiantha (Solanaceae) to assess seed chemical defense in two ways: (1) a plant pathogen inhibition assay using Pythium irregulare; and (2) a brine shrimp toxicity assay using Artemia salina. The combined performance of each species in the two assays positively correlated with seedbank persistence. In the pathogen assay, mycelium growth was reduced when Pythium was cultured o...

Energy Technology Data Exchange (ETDEWEB)

Activated charcoal was produced from sawdust of Pinus caribaea var. caribaea, pinus caribaea var. honduenais and pinus cocarpa, with the objective of studying a alternative of more economic uses for forest residues and the products of the first thinning. A chemical process was utilized based on Zn Cl{sub 2} at temperature of 700 deg C and 450 deg C. It was concluded that the temperature of 700 Celsius produced a activated charcoal with better quality and greater adsorption capacity. The temperature of 450 deg C produced a material with adsorption properties for utilization where greater adsorption capacity is not needed. The production of activated charcoal is possible from the three species of tropical pinus studied. (author). 16 refs., 5 tabs

Energy Technology Data Exchange (ETDEWEB)

Papers presented at the workshop include: the longterm viability of mined land in Queensland; the determination and achievement of rehabilitation objectives: a state government objective; monitoring native vegetation in regenerated bauxite mines at Weipa: a belt transect method; rehabilitation strategies at the Collinsville open cut coal mine; the alteration of the environment by the construction and operation of the coal export facility at Abbot Point; some aspects of the premining environment at Collinsville; the prospects for long term revegetation of acid coal mine spoil and reject materials; recovery and stability in disturbed and artificially revegetated plant communities: a theoretical viewpoint; revegetation in the arid tropics: Mount Isa Mines' experience; Nabralek and its rehabilitation; rehabilitation and management strategies for acid mine wastes; the purpose and design of water quality monitoring networks at mine sites; Worsley alumina project ...

International Nuclear Information System (INIS)

Severe depletion of nutrients through removal of the above ground litter caused a cessation of growth of a Eucalyptus exserta forest in tropical China. Since there is no above ground input of C in this forest, microbial biomass (C_m_i_c) and soil organic C (C_o_r_g) are maintained by the below ground input only. By determining the maintenance requirement of the soil microflora, it should be possible to estimate the below ground production of this forest. To check this hypothesis the authors performed an experiment with labelled C. Since large scale production and field application of "1"4C labelled Eucalyptus litter were not feasible, 'naturally labelled' C_4 plant litter (Zea mays) was used. Maize litter has a #delta#"1"3C of -12.7 per mille as compared with a #delta#"1"3C of -30.7 per mille for Eucalyptus leaf litter. The "1"3C abundance is used to determine the amount of maize C in each of the soil layers. Investigations were made of how supplementation of the ...

International Nuclear Information System (INIS)

The slow or stagnant rate of nuclear power generation development in many developed countries over the last two decades has resulted in a significant shortage in the population of mid-career nuclear industry professionals. This shortage is even more pronounced in some specific areas of expertise such as radiological protection, waste management and decommissioning. This situation has occurred at a time when the renaissance of nuclear power and the globalization of the nuclear industry are steadily gaining momentum and when the industry's involvement in international and national debates in these three fields of expertise (and the industry's impact on these debates) is of vital importance. This paper presents the World Nuclear Association (WNA) approach to building and enhancing worldwide industry cooperation in radiological protection, waste management and decommissioning, which is manifested through the activities of the two WNA working groups on radiological protection (RPWG) and on ...

Energy Technology Data Exchange (ETDEWEB)

This work is a theoretical investigation on the physical properties of semiconductor-based two-dimensional photonic crystals, in particular for what concerns systems embedded in planar dielectric waveguides (GaAs/AlGaAs, GaInAsP/InP heterostructures, and self-standing membranes) or based on macro-porous silicon. The photonic-band structure of photonic crystals and photonic-crystal slabs is numerically computed and the associated light-line problem is discussed, which points to the issue of intrinsic out-of-lane diffraction losses for the photonic bands lying above the light line. The photonic states are then classified by the group theory formalism: each mode is related to an irreducible representation of the corresponding small point group. The optical properties are investigated by means of the scattering matrix method, which numerically implements a variable-angle-reflectance experiment; comparison with experiments is also provided. The analysis of surface reflectance proves the ...

International Nuclear Information System (INIS)

The process of infrared multiple photon dissociation (IRMPD) of molecules is of great fundamental importance and has practical significance, such as isotope separation etc. Unfortunately, a clear insight into the process has been hindered by the bewildering array of important variables affecting MPD. The dissociation probability #gamma#(#phi#) i.e. the yield has been found to be a sensitive function of laser fluence #phi# along with numerous other parameters like laser frequency, gas pressure etc. We have shown that in single frequency IRMPD an accurate quantitative characterization of the dissociation probability can be adequately expressed by a 'power law' model with two fitting parameters namely critical fluence, #phi#c and multi photon order, m. This model was exploited in analysing our MPD results on various systems. However, the small isotope shift encountered in heavy elements and the sticking phenomenon observed in small light molecules restrict respectively the separation ...

International Nuclear Information System (INIS)

During Phase 2 of our study of the CIXS conceptual design we have tackled additional important issues that are unique to the ITER environment. These include the thermal control of the crystal and detector enclosures located in an environment with a 100-250 C ambient temperature, tritium containment, and the range of crystal and detector movement based on the need for spectral adjustments and the desire to make measurements of colder plasmas. In addressing these issues we have selected a ''Dewar''-type enclosure for the crystals and detectors. Applying realistic view factors for radiant heat and making allowance for conduction we have made engineering studies of this enclosure and showed that the cooling requirements can be solved and the temperature can be kept sufficiently constant without compromising the specification parameters of the CIXS. We have chosen a minimum 3 mm combined thickness of the six beryllium windows needed in a Dewar-type enclosure and showed ...

International Nuclear Information System (INIS)

There are several concerns which bring to consider natural gas as a viable alternative to liquid fuels in transport. First, natural gas allows the curbing of global pollution in this steadily growing industry. Indeed, decoupling greenhouse gas emissions from transport growth has become a major issue in tackling climate change. Second, a more extensive use of natural gas would relieve city air quality, which is presently at levels harmful of human health. Nonetheless, this is just one side of the coin. The other side entails building a refuelling station network, and this carries financial requirements. The financing fraction holds a pivotal role in deciding whether natural gas for automotive purposes is an efficient solution. The final aim of this work is, therefore, to compare the natural gas advantages, stemming from avoided global and local emission, with the economic rationale of engaging in supplementary model network investments. A system dynamics model ...

Science.gov (United States)

Taeniasis has been known as one of the prevalent parasitic infections in Korea. Until recently, Taenia saginata had long been considered a dominant, and widely distributed species but epidemiological profiles of human Taenia species in Korea still remain unclear. In order to better understand distribution patterns of human Taenia tapeworms in Korea, partial nucleotide sequences of mitochondrial cox1 and ITS2 (internal transcribed spacer 2) were determined, along with morphological examinations, on 68 Taenia specimens obtained from university museum collections deposited since 1935. Genomic DNA was extracted from formalin-preserved specimens. Phylogenetic relationships among the genotypes (cox1 haplotype) detected in this study were inferred using the neighbor-joining method as a tree building method. Morphological and genetic analyses identified 3 specimens as T. solium, 51 specimens as T. asiatica, and 14 specimens as T. saginata. Our results indicate that all 3 ...

Energy Technology Data Exchange (ETDEWEB)

Electronic trap densities at the indium tin oxide (ITO)/hole transport layer (HTL) interface in operating organic light-emitting diodes (OLEDs) are characterized in situ using impedance spectroscopy. For OLEDs with a high density of active trap states, negative values of the frequency derivative of resistance are clearly observable for frequencies on the order of 10 kHz, whereas positive values are observed when the trap density is low With this technique, it is revealed that the trap density is minimized via the introduction of a TPD-Si{sub 2} (4,4'-bis[(p-trichlorosilylpropylphenyl) phenylamino]-biphenyl) passivation layer at the ITO/HTL interface or by the application of large electric fields during device operation. Furthermore, impedance spectroscopy illustrates that the ITO/HTL interface is not a simple series resistance when traps are present since they are shown not to contribute to high frequency conduction. Overall, this paper demonstrates that the ...

International Nuclear Information System (INIS)

We consider the possibility of a cyclotron-autoresonance-maser (CARM) klystron configuration for accelerator applications as an alternative to the gyroklystron amplifier. The potential advantages, compared to gyroklystrons, include: 1) comparable efficiencies at lower values of the electron beam pitch ratio #alpha#, which should improve the beam quality and make the device substantially more stable against the excitation of parasitic mode, 2) operation far from cutoff, which should reduce the fields at cavity walls, allowing higher power operation, and 3) operation at lower magnetic fields for the same cyclotron harmonic number. However, there are two significant issues associated with the design of efficient, high-power CARMs. First, because of the higher value of k_Z, compared to gyroklystrons, CARMs are substantially more sensitive to parallel velocity spread (pitch-angle spread). Second, conventional cavities support a variety of near-cutoff modes, which can ...

Energy Technology Data Exchange (ETDEWEB)

This final report for the Swiss Federal Office of Energy looks at the possibilities for improved waste water utilization in the Lavey-les-Bains thermal spa, Switzerland. According to the regulations in force, the temperature of the waste water rejected into the Rhone river shall not exceed 30 {sup o}C, what is currently not the case. Also the operational cost shall be reduced and the waste water quality improved. The installations are presented. From the two geothermal wells, mineral water comes out at an average flow rate of 940 l/min and a temperature of 63 {sup o}C. Actual waste water data are reported. The measured thermal water consumption data, including seasonal variations, are analysed by computerized simulation and measures to reduce the consumed volume by the optimization of internal procedures are evaluated. Measures to reduce the quantity of the rejected free chlorine are discussed. Several possible adaptations of the existing space heating, domestic water heating and ...

International Nuclear Information System (INIS)

Short note. The World Health Organization (WHO) has taken aim at critics of irradiated food, claiming that the process has the potential to reduce the incidence of foodborne diseases such as salmonellosis, to cut postharvest food losses and to provide a wider variety of foods for consumers. 'The unwarranted rejection of this process, often based on lack of understanding of what food irradiation entails, may hamper its use in those countries which may benefit most', Dr. Jean-Paul Jardel, WHO's assistant director-general, argued following a recent international conference on the subject. Critics, including Canadians, has opposed food irradiation for years, claiming that more needs to be known about its effects. WHO said the 'vast majority' of the 54 national delegations at the conference supported use of the technology on foods ranging from grain and potatoes to poultry, tropical fruit and strawberries. WHO wants governments to educate the public on the benefits and ...

Energy Technology Data Exchange (ETDEWEB)

Selected local woods and their wood-polymer combinations or composites (WPC) were tested for their thermal conductivity and their fire resistance. WPC were prepared by polymerizing monomers ''in situ'' in oven dried woods by gamma radiation. The monomers included acrylonitrile (AN), 60% styrene-40% acrylonitrile (STAN), methyl methacrylate (MMA), 95% methyl methacrylate-5% dioxane (MD), and vinylidene chloride (VDC). A reduction in thermal conductivity was exhibited by all the composites prepared. W-PAN showed the greatest reduction in thermal conductivity and W-PSTAN in general showed the least. An explanation is suggested for this behaviour. The polymers PMMA and PMD were found to enhance flammability of the woods while PVDC, PAN, and PSTAN imparted fire resistance to the woods. Of the six local woods studied, Ramin-and-Keruing-polymer composites showed the highest flammable tendencies obtained. The correlation of thermal conductivity to ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports thermal comfort and indoor air quality (IAQ) studies of an under-floor air-conditioning (UFAC) system in a hot and humid climate. Thermal comfort parameters were measured at pre-determined grid points within an imaginary plane to predict the air flow pattern of the supply air jet as well as to determine the occurrence of thermal stratification in the office space. Fanger's thermal comfort index was also computed to detect the occupants' thermal sensation. Besides, the concentration levels of dust and carbon dioxide were recorded with the intention to examine the quality of the indoor air. Statistical methods were applied to derive the relationship between air velocity and the other parameters as mentioned earlier. The main findings from the study revealed reasonable level of acceptability of IAQ associated with the UFAC system. However, occupants are likely to experience localised thermal discomfort near the supply diffusers due to the existence of ...

Energy Technology Data Exchange (ETDEWEB)

Emissions of nitric oxide from soils of equatorial rain forest were measured in the Dimonika Natural Park (4 degrees 30'S, 12 degrees 30'E) in the Mayombe Forest in Congo. Three research campaigns were carried out in June and July 1991 and in February 1992. Fluxes were measured by dynamic chamber techniques using a chemiluminescence instrument Scintrex LMA3. NO fluxes measured on natural soils are in between 5 and 17x10[sup 9] molecules cm[sup -2]s[sup -1]; they are of the same order of magnitude as those observed in similar tropical forest media. Soil treatment experiments show that the auto-decomposition of HNO[sub 2] in these acid soils (pH 4) (chemodenitrification) is a potentially important cause of nitric oxide production in this type of ecosystem. Nitrous acid comes from autotrophic nitrification all the year around, and also from biological denitrification, shown by N[sub 2]O emissions, during the rainy season. The regulation of NO release ...

Science.gov (United States)

Antibodies to Ehrlichia canis were detected by indirect immunofluorescence in sera from 233 of 2,077 (11%) military working dogs in various locations throughout the world and from 535 of 938 (57%) civilian dogs in the United States during a 1-year period of study. Overall, E canis infection rates ranged from 13% in the tropical and temperate zones below 45 degrees N to 8% in the cold zone north of 45 degrees N latitude. The highest antibody prevalence rate (24%) was found among a select population of dogs stationed between 40 degrees and 45 degrees north latitude (Japan and Okinawa). The seropositive military dogs did not have clinical signs of ehrlichiosis, thus indicating that the predominant form of infection was subclinical. On the other hand, 216 (23%) of the seropositive civilian dogs had various signs of the disease. The difference was attributed to the fact that the sera from civilian dogs were submitted by practitioners who suspected the disease. ...

Energy Technology Data Exchange (ETDEWEB)

In the year 1996 the spheres of competence of several DLR-Institutes working in the areas of fluid dynamics, reaction kinetics, combustion, numerical methods and laser measuring techniques have been brought together while contributing to the internal DLR project 'combustion chamber modelling (BKM)', in order to proceed with the computational simulation of combustion processes in combustion chambers of gas turbines. The main issue was the development of a research code for numerical simulation of fluid flow in real combustion chambers. Here the development of computational models of physical and chemical processes was emphasized, among other processes the formation of soot was treated. Moreover, a worldwide outstanding database of measured data for the purpose of code validation has been created within the framework of the BKM project using the laboratory facilities of the DLR, which are in Germany unique for the experimental investigation of the various processes in ...

Energy Technology Data Exchange (ETDEWEB)

Ninety-five nests of Centris (Heterocentris) terminata Smith were collected in trap nests, during November/2001 and January/2003, at two fragments (PZGV e CFO-UFBA) of secondary Atlantic Forest, in Salvador, Bahia State (13 deg 01' W and 38 deg 30' S). The highest nest frequencies occurred from December to February (summer), with no nests foundations from August to October (winter - early spring). Two-hundred eight adults emerged from 347 brood cells, being 164 males and 116 females (1: 0.42). During the study period sex ratio was male biased ({chi}{sup 2} = 9.342; gl = 10; P < 0.05). C. terminata nested in holes with diameters 6, 8, 10 mm, but 84,2% were constructed in 8 and 10 mm. nests had one to seven cells arranged in a linear series with the cell's partitions built with a mixture of sand and resin or oil. Male is significantly smaller than female, which emerges from the first cells constructed. Immature mortality occurred in 14.1% of brood cells ...

Science.gov (United States)

A factor which agglutinated the spores of Ceratocystis fimbriata in the presence of Ca2+ was purified from sweet potato (Ipomea batatas Lam cv. Norin[1]) root. Element composition of the purified factor was as follows; analysis found: C (29.8%), H (3.97%), O (65.34%), N (0.81%): calculated for C43H69O70N1: C (30.02%), H (4.01%), O (65.15%), N (0.81%). The factor was mainly composed of galacturonic acid (53% of dry weight) and contained arabinose, fucose, and unidentified component as minor components. The factor also agglutinated A-, B-, AB-, and O types of human erythrocytes to almost the same degree in the presence of Ca2+. The differential spore-agglutinating activity of the factor depended on the pH of the assay medium; it agglutinated similarly the germinated spores of sweet potato and coffee strains at pH 7.5 and 5.5, whereas it displayed a distinct differential agglutinating activity at pH 6.5. The factor was assayed for spore-agglutinating activity at pH 6.5, using the ...

Energy Technology Data Exchange (ETDEWEB)

The high voltage/high power DC-cathode power supply for the Gyrotron Test Facility at the Forschungszentrum in Karlsruhe consists of a 12-pulse thyristor star-point-controller, a 130 kV capacitor-bank followed by a tetrode regulator. Originally designed for 80 kV/30 A CW (continous-wave) operation, its operating regime has been extended in line with gyrotron development to pulses of 65 kV/45 A/3 min and more recently to 65 kV/80 A/10 s without any changes to the main load bearing components (thyristors, transformers or power tetrode). This allows testing of gyrotrons in the 0.5 MW (CW), 1 MW (3 min) and 2 MW (10 s) output power range. The paper describes the system, its operation and some critical aspects of the last upgrade, such as the issue of harmonics in the 20 kV distribution mains-grid, the dynamic response of the thyristor-controller and the avoidance of microwave parasitic oscillations in the high power tetrode (a CQK-200-4, developed by ABB, Switzerland ...

Science.gov (United States)

SUMMARY: Gastrointestinal helminths of Norway rat (Rattus norvegicus) from the Belgrade area were studied as a part of a wider ecological research of rats in Serbia (data on the distribution, population ecology, economic and epizoothiological-epidemiological importance, and density control). Rats were captured from May 2005 to July 2009 at both urban and suburban-rural sites. Of a total of 302 trapped rats 48% were males and 52% females, with 36.5% and 38.8% of juvenile-subadult individuals, per sex respectively. Intestinal helminth infection was noted in 68.5% of rats, with a higher prevalence in male hosts and in adult individuals. Higher numbers of infected juveniles-subadults were noted in suburban-rural habitats, while an opposite tendency was noted in adult rats. Seven helminth species were recovered, of which five were nematode (Heterakis spumosa, Nippostrongylus brasiliensis, Capillaria sp., Trichuris muns and Syphacia muris) and two cestode species (Hymenolepis diminuta and ...

Energy Technology Data Exchange (ETDEWEB)

Effective commercial liquid absorption technology currently applicable for CO{sub 2} capture from power plant flue gases uses a conventional chemical solvent, MEA(monoethanolamine), which was developed over 60 years ago as general non selective solvent to remove acid gases from natural gas streams. The application to CO{sub 2} capture from almost atmospheric pressure flue gases required modification of the technology on account of the oxygen content to incorporate inhibitors to resist solvent degradation and equipment corrosion, as well as upstream treatment of the flue gases to remove both SO{sub x} and NO{sub x} present. The solvent strength used by such processes is relatively low in comparison with high strength modern chemical solvents. The resultant effect is large equipment and high regeneration energy requirements which is a parasitic load on the power plant. Using current technology for CO{sub 2} capture from flue gas derived from conventional pulverized ...

Energy Technology Data Exchange (ETDEWEB)

During outbreaks, Microdiprion pallipes (Fall.) is the most destructive of the pine sawflies in Sweden. Its distribution includes most provinces, but damaging outbreaks have until recently occurred only in two inland areas in northern Sweden. These areas are characterised by high elevation, a harsh climate, and slow tree growth. The four recorded outbreak periods showed a 10 year periodicity. Outside these areas, a lesser outbreak occurred in 1988 to 1990, on the east coast (province of Uppland). Outbreak patterns, life history variation, and mortality factors were studied. Factors that may explain the distribution of outbreaks and the population patterns were identified.Experimental and observational evidence on the potential of various factors to influence fecundity, dispersal, and survival was evaluated. In the outbreak areas, there were few major population factors. Parasitism by Rhorus substitutor (Thunb.) was the largest cause of larval mortality and the only ...

Energy Technology Data Exchange (ETDEWEB)

Palmer Drought Severity Index (PDSI) monthly data are analyzed, building on a previous study that investigated the influence of the El Nino/Southern Oscillation (ENSO) on US streamflow. Harmonic analysis is performed using data from 1,035 selected climatological stations, allowing observation of the biennial tendency in climate data. With the middle twelve months defined as the El Nino year (0), an idealized first harmonic fit to a 24-month ENSO composite is computed for each station. By plotting the first harmonic vectors of each station, regions of similar, or coherent, response are identified. The regions identified using PDSI data represent wet conditions in the Gulf of Mexico (Gm1 and GM2) and central (C) US, and dry conditions in the Pacific northwest (PNW) and northeast (NE) US. The PNW region exhibits the strongest interrelationship between ENSO and extreme drought events. Comparing PDSI data results with other hydroclimatic data (temperature, precipitation, and streamflow) ...

Energy Technology Data Exchange (ETDEWEB)

This paper reported on a study in which designs for Chinese and Indian fixed-dome anaerobic digesters were modified in an effort to produce smaller and more affordable digesters. While these types of systems are common in tropical regions of developing countries, they have not been used in colder climates because of the low biogas yield during the winter months. Although there is evidence that sufficient biogas production can be maintained in colder temperatures through design and operational changes, there is a lack of knowledge about the seasonal changes in the composition of the microbial communities in ambient temperature digesters. More knowledge is needed to design and operate systems for maximum biogas yield in temperate climates. The purpose of this study was to cultivate a microbial community that maximizes biogas production at psychrophilic temperatures. The study was conducted on a 300 gallon experimental anaerobic digester on the campus of Ohio State ...

International Nuclear Information System (INIS)

Total mercury (THg), methylmercury (MeHg) and 22 other trace elements were measured in ice algae, three species of zooplankton, mixed zooplankton samples, Arctic cod (Boreogadus saida), ringed seals (Phoca hispida) and eight species of seabirds to examine the trophodynamics of these metals in an Arctic marine food web. All samples were collected in 1998 in the Northwater Polynya (NOW) located between Ellesmere Island and Greenland in Baffin Bay. THg and MeHg were found to biomagnify through the NOW food web, based on significant positive relationships between log THg and log MeHg concentrations vs. #delta# "1"5N muscle and liver . The slope of these relationships for muscle THg and MeHg concentrations (slope = 0.197 and 0.223, respectively) were similar to those reported for other aquatic food webs. The food web behavior of THg and #delta# "1"5N appears constant, regardless of trophic state (eutrophic vs. oligotrophic), latitude (Arctic vs. tropical) or salinity ...

International Nuclear Information System (INIS)

Aerosols affect the radiative energy budget on both the regional and global scales. The wavelength-dependent aerosol optical depth (AOD) is a fundamental determinant of the amount by which extra-terrestrial incoming sunlight and outgoing terrestrial radiation are being attenuated in the atmosphere. The present study addresses the influence of local waste burning on aerosol characteristics, black carbon (BC) aerosol mass concentration and spectral solar irradiance using ground-based measurements over the tropical urban environment of Hyderabad, India. AOD has been observed to be maximum during burning days compared to normal days. Aerosol size spectra suggest bimodal distributions during pre-and post-burning periods and trimodal distributions during burning periods. Angstrom wavelength exponent estimated from spectral variation of AOD suggested dominance of accumulation mode particle loading during burning days compared to normal days. Diurnal variation of BC on ...

International Nuclear Information System (INIS)

Dams and reservoirs are among one of the most sensitive of all development Project, in terms of pervasiveness of their influence in altering the environmental conditions and resources. In the present study, major dams and reservoir projects are reviewed, from the environmental point of view. Dams and Reservoir projects bring about major changes in the immediate environment, thus affecting public health, settlements, farmlands, roads and historical sites. Impacts on human population and wildlife may be profound. Tropical diseases, involving fresh-water hosts or vectors in their transmission, are often common around new reservoirs. Large lakes create limnological changes, excessive evaporation, seepage, disturbance in water-table and increased tendencies of landslides and earthquakes. Micro climatic changes are possible, such as fog formation, increased cloudiness and modified rainfall-patterns. Retention of sediment results in silting up of reservoirs. Water ...

Science.gov (United States)

There are few empirical data, particularly collected simultaneously from multiple sites, on extinctions resulting from human-driven land-use change. Southeast Asia has the highest deforestation rate in the world, but the resulting losses of biological diversity remain poorly documented. Between November 2006 and March 2008, we conducted bird surveys on six landbridge islands in Malaysia and Indonesia. These islands were surveyed previously for birds in the early 1900 s, when they were extensively forested. Our bird inventories of the islands were nearly complete, as indicated by sampling saturation curves and nonparametric true richness estimators. From zero (Pulau Malawali and Pulau Mantanani) to 15 (Pulau Bintan) diurnal resident landbird species were apparently extirpated since the early 1900 s. Adding comparable but published extinction data from Singapore to our regression analyses, we found there were proportionally fewer forest bird extinctions in areas with greater remaining ...

Science.gov (United States)

Quantification of the downed woody materials that comprise forest fuels has gained importance in Caribbean forest ecosystems due to the increasing incidence and severity of wildfires on island ecosystems. Because large-scale assessments of forest fuels have rarely been conducted for these ecosystems, forest fuels were assessed at 121 US Department of Agriculture forest service inventory plots on Puerto Rico, Vieques, and the US Virgin Islands. Results indicated that fuel loadings averaged 24.05 Mg ha(-1) in 2004-2006. Forest litter decreased from wetter to drier forest life zones. These island forests showed a paucity of coarse woody fuels (CWD) (2.91 Mg ha(-1)) and relatively greater quantities of smaller-sized fine woody fuels (FWD) (10.18 Mg ha(-1) for FWD and 10.82 Mg ha(-1) for duff/litter) when compared to continental tropical forests. Between 2001 and 2006, CWD fuel loads decreased, while fine fuels and litter increased, such that total fuel loads remained ...

Energy Technology Data Exchange (ETDEWEB)

Herbivores and pathogens impact the species composition, ecosystem function, and socioeconomic value of forests. Herbivores and pathogens are an integral part of forests, but sometimes produce undesirable effects and a degradation of forest resources. In the United States, a few species of forest pests routinely have significant impacts on up to 20 million ha of forest with economic costs that probably exceed $1 billion/year. Climatic change could alter patterns of disturbance from herbivores and pathogens through: (1) direct effects on the development and survival of herbivores and pathogens; (2) physiological changes in tree defenses; and (3) indirect effects from changes in the abundance of natural enemies (e.g. parasitoids of insect herbivores), mutualists (e.g. insect vectors of tree pathogens), and competitors. Because of their short life cycles, mobility, reproductive potential, and physiological sensitivity to temperature, even modest climate change will have rapid impacts on ...

International Nuclear Information System (INIS)

Beach rocks are observed frequently on the tropical and subtropical sandy beaches where they express thin beds dipping seaward at less than 15 degrees. They consist of beach sediments including fossil shells, fragments of corals, diatoms and other biocarbonates, and are well cemented within the inter-tidal zone with calcium carbonate originated in sea water. Therefore, they are not only good indicators which show the past sea level, but also provide good sample material for radiocarbon dating. The locations of beach rocks give us an optimum condition studying a carbon cycle between land and marine environment by analyzing their isotope fractionations. In order to estimate the origin of calcium carbonate which worked as an adhesive when beach rocks were formed and to estimate the formative ages of beach rocks, a total of 330 fossil corals, fossil shells and calcarenite or calcirdite samples were collected from 128 sites of 16 islands consisting of the Nansei ...