Ecological studies on some lakes of the Amazon valley

Of the three types of lakes studied, clear water, white water, and brown water, the white water lakes are the only ones to have a reasonable autochtonous production of organic matter. Owing probably to the lack of mineral salts, the primary production is very low in the two other types and not very high even in the white waters. The total biomass is high in the white water lakes and the production increases only with rising water level. This may be due to different processes. One is the rains which bring in some quantities of nitrogen, as is well known. The other is the seeping of ground water through the bottom when the general level of the waters around the lake is rising. Of course, when the lake receives water directly from a white water affluent or from the rising Amazon, it also gets a new supply of mineral matter. In the clear and black waters ofthe forest lakes, the organic production is allochtonous and probably the stock of organic material in the lake is increasing progressively with the ecological evolution of the water and with the action of the organisms which store nutrients in their own substance. The autochtonous productivity shows also a small increase when the water level rises but the total biomass always remains small, One of the productivity factors which thus appears important is the number of animals. Firstly these store nutrients which would otherwise be lost to the effluents of the lakes; secondly, they increase the speed of mineralisation of the littoral plant material, which drops into the water, and make it available to the lake cycle. The first process is thus density-dependent, the second density-and-diversity-dependent. The favourable action of the Amazon and white waters on the productivity shows the importance of an accurate hypsometric survey ôf the region for the delimitation of productivity zones in the Amazon basin.Dos três tipos de lagos estudados:.de água clara, âgua branca e água "pteta", são somente os lagos de água branca que possuem uma produção autóctona razoavel de rnatéria orgânica. Devido, provavelmente, à falta de sais minerais, a produção primfuia :#"ta baixa nos dôis outros tipos" sendo mesmo não muito alta tambêm nas águas bran- A biomassa é alta nos lagos de átgua branca, e a produção aumenta somente com a enchente, quer dizer, com o nivel d'água subindo. Este fenómeno pode ter a sua razáo em processos diferentes. IJm deles são as chuvas que trâzem alguma quantidade dè nitrogênio, como bem se sabe, O outro é a penetração de água freâtica atravês do fundo do lago quando sóbe o nivel geral das águas ao redor do lago. E óbvio que o lago quando receber água diretamente dum afluente de água branca ou do enchendo Amazonas mesmo, também ganha um novo suplemento cle rnatéría mineral. Nas águas claras e pretas de lagos florestais, a produção orgânica é allóctona. Parece provavel que o estoque de matéria orgânica, no lago, aumenta progressivamente com a evoluçäo ecológica da âgua e com a ação dos organismos os quais acumulam nutrimentos dentro da própria substância. A produtividade autóctona mostra também um pequeno aumento quando sóbe o nivel da àgua, porém a biomassa total sempre permanece pequena. LT4 IJm dos fatores da produtividade o qual, desta maneir a, parece importante, é o número de animais, Primeiro, eles armazenam nutrimentos os quais, em outro caso, seriam perdidos aos cursos d'água, efluentes dos lagos; segundo, eles aumentam a velocidade da mineralizaçã'o do material, fornecido pelas plantas do litoral, o que cai para dentro da âgua, e tornam-no acessivel ao ciclo do lago. O primeiro processo é, desta forma, dependente da densidade da população animal, o segundo é dependente da densidade e da diversidade da mesma. A ação favoravel do Amazonas e das águas brancas sôbre a produtividade demonstra a importância de um levantamento hipsométrico acurado da região para o fim duma delimitação de zonas de produtividade na ltac-ia arnazönica

The occurrence of 2-hydroxy-6-methoxybenzoic acid methyl ester in Securidaca longepedunculata Fresen root bark

As part of our ongoing search for natural fumigants from Senegalese plants, we have investigated Securicicidaca longepedunculata root barks and demonstrated that 2-hydroxy-benzoic acid methyl ester (methyl salicylate, I) is responsible of their biocide effect against stored grain insects. A second unknown apparented product, II has been systematically observed in all analyzed samples. The present paper describes the identification of this molecule. The analytical investigations including GCMS, GLC and 1H-NMR. spectrometry led to the conclusion that II corresponds to the 2-hydroxy-6-methoxybenzoic acid methyl ester

Composition chimique du netetu, condiment alimentaire produit par fermentation des graines de caroubier africain Parkia biglobosa (Jacq.) Benth.

Chemical composition of netetu, a food condiment from fermented Parkia biglobosa seeds. The seed oils and cakes of netetu of different origins available on the Senegalian market have been studied to evaluate the nutritional potentialities of this important food condiment used in many African countries. The total oil content ranged from 141 to 349 g per kg. Careful gas chromatography and GC-MS (Gas Chromatography-Mass Spectrometry) investigations revealed seven major fatty acids among which linoleic (41.9-46.8/ of the total fatty acids), oleic (12.6-14.6/), palmitic (10.2-11.3/), stearic (10.0-13.4/), and behenic (12.6-13.4/) predominate. Significant differences were observed between fermented and non-fermented seeds as well as between netetu of different origins. The tocopherol content was found very low (17.7 to 30.6 mg per 100g fat). The total amino acid patterns showed that beside high level of proteins (331 a 540 g per kg) and interesting levels of essential constituents, there is an important deficiency of tryptophane, cysteine, methionine and threonine

The genome of a tortoise herpesvirus (testudinid herpesvirus 3) has a novel structure and contains a large region that is not required for replication in vitro or virulence in vivo

Testudinid herpesvirus 3 (TeHV-3) is the causative agent of a lethal disease affecting several tortoise species. The threat that this virus poses to endangered animals is focusing efforts on characterizing its properties, in order to enable the development of prophylactic methods. We have sequenced the genomes of the two most studied TeHV-3 strains (1976 and 4295). TeHV-3 strain 1976 has a novel genome structure and is most closely related to a turtle herpesvirus, thus supporting its classification into genus Scutavirus, subfamily Alphaherpesvirinae, family Herpesviridae. The sequence of strain 1976 also revealed viral counterparts of cellular interleukin-10 and semaphorin, which have not been described previously in members of subfamily Alphaherpesvirinae. TeHV-3 strain 4295 is a mixture of three forms (m1, m2, and M), in which, in comparison to strain 1976, the genomes exhibit large, partially overlapping deletions of 12.5 to 22.4 kb. Viral subclones representing these forms were isolated by limiting dilution, and each replicated in cell culture comparably to strain 1976. With the goal of testing the potential of the three forms as attenuated vaccine candidates, strain 4295 was inoculated intranasally into Hermann's tortoises (Testudo hermanni). All inoculated subjects died, and PCR analyses demonstrated the ability of the m2 and M forms to spread and invade the brain. In contrast, the m1 form was detected in none of the organs tested, suggesting its potential as the basis of an attenuated vaccine candidate. Our findings represent a major step towards characterizing TeHV-3 and developing prophylactic methods against it. IMPORTANCE: Testudinid herpesvirus 3 (TeHV-3) causes a lethal disease in tortoises, several species of which are endangered. We have characterized the viral genome, and used this information to take steps towards developing an attenuated vaccine. We have sequenced the genomes of two strains (1976 and 4295), compared their growth in vitro, and investigated the pathogenesis of strain 4295, which consists of three deletion mutants. The major findings are: (i) TeHV-3 has a novel genome structure; (ii) its closest relative is a turtle herpesvirus; (iii) it contains interleukin-10 and semaphorin genes, the first time these have been reported in an alphaherpesvirus; (iv) a sizeable region of the genome is not required for viral replication in vitro or virulence in vivo; and (v) one of the components of strain 4295, which has a deletion of 22.4 kb, exhibits properties indicating that it may serve as the starting point for an attenuated vaccine

The future role of Scottish local government economic development

Since 1979 local authorities have been subjected to two main pressures from central government: increasing control over the range and type of services that can be provided; and greater emphasis on the private sector's role. So far, beyond being affected by the general financial constraints that local government has been placed under, the economic development services that many local authorities provide have escaped largely unscathed. This situation seems now likely to change radically as a result of three measures. These are:- a) the Local Government and Housing Bill; b) Scottish Enterprise; and c) changes to the structure of local government. When considered in isolation these measures contain much that is attractive and which could produce a more effective economic development service; for example, a specific power to carry out economic development and the creation of an integrated training and enterprise development service. However the argument that is put forward in this paper is that these measures have to be seen as complementary. They are part of an overall strategy intended to result in a major reduction in local government's local economic development activities

Molecular characterisation of virulence graded field isolates of myxoma virus

<p>Abstract</p> <p>Background</p> <p><it>Myxoma virus </it>(MV) has been endemic in Europe since shortly after its deliberate release in France in 1952. While the emergence of more resistant hosts and more transmissible and attenuated virus is well documented, there have been relatively few studies focused on the sequence changes incurred by the virus as it has adapted to its new host. In order to identify regions of variability within the MV genome to be used for phylogenetic studies and to try to investigate causes of MV strain attenuation we have molecularly characterised nine strains of MV isolated in Spain between the years 1992 and 1995 from wide ranging geographic locations and which had been previously graded for virulence by experimental infection of rabbits.</p> <p>Results</p> <p>The findings reported here show the analysis of 16 genomic regions accounting for approximately 10% of the viral genomes. Of the 20 genes analysed 5 (M034L, M069L, M071L, M130R and M135R) were identical in all strains and 1 (M122R) contained only a single point mutation in an individual strain. Four genes (M002L/R, M009L, M036L and M017L) showed insertions or deletions that led to disruption of the ORFs.</p> <p>Conclusions</p> <p>The findings presented here provide valuable tools for strain differentiation and phylogenetic studies of MV isolates and some clues as to the reasons for virus attenuation in the field.</p

Development and demonstration of a Lagrangian dispersion modeling system for real‐time prediction of smoke haze pollution from biomass burning in Southeast Asia

Abstract Transboundary smoke haze caused by biomass burning frequently causes extreme air pollution episodes in maritime and continental Southeast Asia. With millions of people being affected by this type of pollution every year, the task to introduce smoke haze related air quality forecasts is urgent. We investigate three severe haze episodes: June 2013 in Maritime SE Asia, induced by fires in central Sumatra, and March/April 2013 and 2014 on mainland SE Asia. Based on comparisons with surface measurements of PM10 we demonstrate that the combination of the Lagrangian dispersion model NAME with emissions derived from satellite‐based active‐fire detection provides reliable forecasts for the region. Contrasting two fire emission inventories shows that using algorithms to account for fire pixel obscuration by cloud or haze better captures the temporal variations and observed persistence of local pollution levels. Including up‐to‐date representations of fuel types in the area and using better conversion and emission factors is found to more accurately represent local concentration magnitudes, particularly for peat fires. With both emission inventories the overall spatial and temporal evolution of the haze events is captured qualitatively, with some error attributed to the resolution of the meteorological data driving the dispersion process. In order to arrive at a quantitative agreement with local PM10 levels, the simulation results need to be scaled. Considering the requirements of operational forecasts, we introduce a real‐time bias correction technique to the modeling system to address systematic and random modeling errors, which successfully improves the results in terms of reduced normalized mean biases and fractional gross errors