Experimental acidification of a poor fen in northwestern Ontario: Effects on emergence of Chironomidae (Diptera)

Energy Technology Data Exchange (ETDEWEB)

Rosenberg, D.M.; Wiens, A.P.; Bilyj, B. [Department of Fisheries and Oceans, Winnipeg, MB (Canada). Central and Arctic Region; Armstrong, L. [Department of Fisheries and Oceans, Winnipeg, MB (Canada). Central and Arctic Region

1995-10-01

The effects of experimental acidification and N fertilization on chironomid emergence from a poor fen in northwestern Ontario were studied from 1984 to 1989. Experimental treatments did not affect the numbers of chironomids emerging weekly, the timing of emergence, or the species composition of emergence during the study period. Weekly emergence counts were higher (P<0.05) from the periphery of the fen than the central part. Total seasonal emergence was higher from an area that was previously burned than from the rest of that swamp, though the difference was not statistically significant. Stability of species composition, despite experimental treatments and physiographic differences in the fen, may be a widespread characteristic of Canadian acidic peatlands. 7 tabs., 4 figs., 23 refs.

The Acid-Base Balance Between Organic Acids and Circumneutral Ground Waters in Large Peatlands

Science.gov (United States)

Siegel, D. I.; Glaser, P. H.; So, J.

2006-05-01

Organic acids supply most of the acidity in the surface waters of bogs in peatlands. Yet, the fundamental geochemical properties of peatland organic acids are still poorly known. To assess the geochemical properties of typical organic acid assemblages in peatlands, we used a triprotic analog model for peat pore waters and surface waters in the Glacial Lake Agassiz Peatlands, optimizing on charge balance and calibrated to estimates of mole site density in DOC and triprotic acid dissociation constants. Before the calibration process, all bog waters and 76% of fen waters had more than +20% charge imbalance. After calibration, most electrochemically balanced within 20%. In the best calibration, the mole site denisty of bog DOC was estimated as ~0.05 mmol/mmol C., approximately 6 times smaller than that for fen DOC or the DOC in the fen deeper fen peats that underlie bogs. The three modeled de-protonation constants were; pKa1 = ~3.0, pKa2 = ~4.5 and pKa3 = ~7.0 for the bog DOC, and; pKa1 = ~5.2, pKa2 =~ 6.5 and pKa3 = ~7.0 for the fen DOC. Bog DOC, behaves as a strong acid despite its small mole site density. The DOC in bog runoff can therefore theoretically acidify the surface waters in adjacent fens wherever these waters do not receive sufficient buffering alkalinity from active groundwater seepage.

On the non-closure of particle backscattering coefficient in oligotrophic oceans.

Science.gov (United States)

Lee, ZhongPing; Huot, Yannick

2014-11-17

Many studies have consistently found that the particle backscattering coefficient (bbp) in oligotrophic oceans estimated from remote-sensing reflectance (Rrs) using semi-analytical algorithms is higher than that from in situ measurements. This overestimation can be as high as ~300% for some oligotrophic ocean regions. Various sources potentially responsible for this discrepancy are examined. Further, after applying an empirical algorithm to correct the impact from Raman scattering, it is found that bbp from analytical inversion of Rrs is in good agreement with that from in situ measurements, and that a closure is achieved.

Unravelling hydrological mechanisms behind fen deterioration

NARCIS (Netherlands)

van Loon, A.H.

2010-01-01

Low-productive fens are wetland ecosystems that have strongly declined in number and size in temperate regions of Western Europe since World War II. This fen type has significant conservation value in many countries because of its high species diversity and the presence of endangered plant species.

Incidental oligotrophication of North American Great Lakes.

Science.gov (United States)

Evans, Mary Anne; Fahnenstiel, Gary; Scavia, Donald

2011-04-15

Phytoplankton production is an important factor in determining both ecosystem stability and the provision of ecosystem goods and services. The expansive and economically important North American Great Lakes are subjected to multiple stressors and understanding their responses to those stresses is important for understanding system-wide ecological controls. Here we show gradual increases in spring silica concentration (an indicator of decreasing growth of the dominant diatoms) in all basins of Lakes Michigan and Huron (USA and Canadian waters) between 1983 and 2008. These changes indicate the lakes have undergone gradual oligotrophication coincident with and anticipated by nutrient management implementation. Slow declines in seasonal drawdown of silica (proxy for seasonal phytoplankton production) also occurred, until recent years, when lake-wide responses were punctuated by abrupt decreases, putting them in the range of oligotrophic Lake Superior. The timing of these dramatic production drops is coincident with expansion of populations of invasive dreissenid mussels, particularly quagga mussels, in each basin. The combined effect of nutrient mitigation and invasive species expansion demonstrates the challenges facing large-scale ecosystems and suggest the need for new management regimes for large ecosystems.

Experimental restoration of a fen plant community after peat mining

Energy Technology Data Exchange (ETDEWEB)

Cobbaert, D.; Rochefort, L.; Price, J.S. [Univ. Laval, Sainte-Foy (Canada). Dept. de Phytologie

2004-11-01

Methods: The effectiveness of introducing fen plants with the application of donor diaspore material was tested. The donor diaspore material, containing seeds, rhizomes, moss fragments, and other plant propagules, was collected from two different types of natural fens. We tested whether the application of straw mulch would increase fen species cover and biodiversity compared to control plots without straw mulch. Terrace levels of different peat depths (15 cm, 40 cm, and 56 cm) were created to test the effects of different environmental site conditions on the success of re-vegetation. Results: Applying donor seed bank from natural fens was found to significantly increase fen plant cover and richness after the two growing seasons. Straw mulch proved to significantly increase fen plant richness. The intermediate terrace level (40 cm) had the highest fen plant establishment. Compared to reference sites, the low terrace level (15 cm) was richer in base cations, whereas the high terrace level (56 cm) was much drier. Conclusions: The application of donor diaspore material was demonstrated as an effective technique for establishing vascular fen plants. Further rewetting measures are considered necessary at the restoration site to create a fen ecosystem rather than simply restoring some fen species (Location: Riviere-du-Loup peatland, southern Quebec, Canada at 100 m a.s.l.)

Emissions of biogenic sulfur gases from northern bogs and fens

Science.gov (United States)

Demello, William Zamboni; Hines, Mark E.; Bayley, Suzanne E.

1992-01-01

Sulfur gases are important components of the global cycle of S. They contribute to the acidity of precipitation and they influence global radiation balance and climate. The role of terrestrial sources of biogenic S and their effect on atmospheric chemistry remain as major unanswered questions in our understanding of the natural S cycle. The role of northern wetlands as sources and sinks of gaseous S by measuring rates of S gas exchange as a function of season, hydrologic conditions, and gradients in tropic status was investigated. Experiments were conducted in wetlands in New Hampshire, particularly a poor fen, and in Mire 239, a poor fen at the Experimental Lakes Area (ELA) in Ontario. Emissions were determined using Teflon enclosures, gas cryotrapping methods and gas chromatography (GC) with flame photometric detection. Dynamic (sweep flow) and static enclosures were employed which yielded similar results. Dissolved S gases and methane were determined by gas stripping followed by GC.

High resistance of some oligotrophic bacteria to ionizing radiation

International Nuclear Information System (INIS)

Nikitin, D.I.; Tashtemirova, M.A.; Pitryuk, I.A.; Sorokin, V.V.; Oranskaya, M.S.; Nikitin, L.E.

1994-01-01

The resistance of seven cultures of eutrophic and oligotrophic bacteria to gamma radiation (at doses up to 360 Gy) was investigated. The bacteria under study were divided into three groups according to their survival ability after irradiation. Methylobacterium organophilum and open-quotes Pedodermatophilus halotoleransclose quotes (LD 50 = 270 Gy) were highly tolerant. By their tolerance, these organisms approached Deinococcus radiodurans. Aquatic ring-shaped (toroidal) bacteria Flectobacillus major and open-quotes Arcocella aquaticaclose quotes (LD 5 = 173 and 210 Gy, respectively) were moderately tolerant. Eutrophic Pseudomonas fluorescens and Escherichia coli (LD 50 = 43 and 38 Gy, respectively) were the most sensitive. X-ray microanalysis showed that in tolerant bacteria the intracellular content of potassium increased and the content of calcium decreased after irradiation. No changes in the element composition of the eutrophic bacterium E. coli were detected. Possible mechanisms of the resistance of oligotrophic bacteria to gamma radiation are discussed

Fens As Ecohydrologic Gauges of Climate Change in California

Science.gov (United States)

Drexler, J. Z.; Flint, L. E.; Flint, A. L.; Knifong, D. L.

2014-12-01

The purpose of this study was to demonstrate the use of montane groundwater-fed peatlands called fens as gauges for changes in groundwater recharge through time. Due to their consistent groundwater flows, fens remain saturated during the growing season, thus serving as ecological refugia for a range of sensitive biota including the federally threatened Yosemite toad (Anaxyrus canorus). In this project, five fens in the Sierra Nevada and two in the southern Cascade Mountains were studied over a 50-80 year period using historic aerial photography and GIS analysis. Fen areas were delineated using vegetation distributions and site wetness as visual keys to fen areal extent. In addition, a climate analysis of precipitation, snowpack, evapotranspiration, and mean minimum monthly temperature (Tmin) was carried out for the years 1950 - 2010 using a distributed parameter water-balance model called the Basin Characterization Model. Over the study period, all five Sierra fens decreased by 10-15% in delineated area, but little change occurred in the Cascade fens. The climate analysis revealed major changes through time in Tmin and the frequency of June months with zero snowpack (snowpack longevity) at the five Sierra sites. At the Cascade sites, increases in Tmin occurred more recently and decreases in snowpack longevity were more subtle. The different behavior of fens in the Cascades versus the Sierra Nevada suggests that underlying geology, particularly hydraulic conductivity, rock porosity, and size of groundwater reservoirs, may be an important buffer to change. These results show that fens in the Sierra Nevada are highly responsive ecohydrologic gauges that can be used to track reductions in groundwater recharge due to climate change. Further studies using isotopic and/or geochemical approaches are needed to quantify the changes in groundwater recharge that were identified with fens. Because fens provide critical habitat for sensitive species, major changes in hydrology

Interaction between APC and Fen1 during breast carcinogenesis.

Science.gov (United States)

Narayan, Satya; Jaiswal, Aruna S; Law, Brian K; Kamal, Mohammad A; Sharma, Arun K; Hromas, Robert A

2016-05-01

Aberrant DNA base excision repair (BER) contributes to malignant transformation. However, inter-individual variations in DNA repair capacity plays a key role in modifying breast cancer risk. We review here emerging evidence that two proteins involved in BER - adenomatous polyposis coli (APC) and flap endonuclease 1 (Fen1) - promote the development of breast cancer through novel mechanisms. APC and Fen1 expression and interaction is increased in breast tumors versus normal cells, APC interacts with and blocks Fen1 activity in Pol-β-directed LP-BER, and abrogation of LP-BER is linked with cigarette smoke condensate-induced transformation of normal breast epithelial cells. Carcinogens increase expression of APC and Fen1 in spontaneously immortalized human breast epithelial cells, human colon cancer cells, and mouse embryonic fibroblasts. Since APC and Fen1 are tumor suppressors, an increase in their levels could protect against carcinogenesis; however, this does not seem to be the case. Elevated Fen1 levels in breast and lung cancer cells may reflect the enhanced proliferation of cancer cells or increased DNA damage in cancer cells compared to normal cells. Inactivation of the tumor suppressor functions of APC and Fen1 is due to their interaction, which may act as a susceptibility factor for breast cancer. The increased interaction of APC and Fen1 may occur due to polypmorphic and/or mutational variation in these genes. Screening of APC and Fen1 polymorphic and/or mutational variations and APC/Fen1 interaction may permit assessment of individual DNA repair capability and the risk for breast cancer development. Such individuals might lower their breast cancer risk by reducing exposure to carcinogens. Stratifying individuals according to susceptibility would greatly assist epidemiologic studies of the impact of suspected environmental carcinogens. Additionally, a mechanistic understanding of the interaction of APC and Fen1 may provide the basis for developing new and

Causes of change in nitrophytic and oligotrophic lichen species in a Mediterranean climate: Impact of land cover and atmospheric pollutants

Energy Technology Data Exchange (ETDEWEB)

Pinho, P.; Augusto, S.; Martins-Loucao, M.A. [Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Universidade de Lisboa, edificio C4, 1749-016 Lisbon (Portugal); Pereira, M.J.; Soares, A. [Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Cerena, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Maguas, C. [Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Universidade de Lisboa, edificio C4, 1749-016 Lisbon (Portugal); Branquinho, C. [Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Universidade de Lisboa, edificio C4, 1749-016 Lisbon (Portugal); Antiga Fabrica da Polvora de Barcarena, Universidade Atlantica, 2745-615 Barcarena (Portugal)], E-mail: cmbranquinho@fc.ul.pt

2008-08-15

With the aim of determining the main drivers of changes in nitrophytic and oligotrophic macro-lichen communities in an industrial region with a Mediterranean climate, we considered both land-cover types and atmospheric pollutants. We determined the relation between the abundance of nitrophytic and oligotrophic species with environmental factors considering the distance of influence of land-cover types. The results showed that oligotrophic species decreased in the proximity of artificial areas, barren land and agricultural areas, associated with higher concentrations of NO{sub 2} and Zn, and Ti, probably dust of industrial and agricultural origin. Nitrophytic species were positively related to all the mentioned land-cover types, and with higher concentrations of Fe and N. Magnesium, probably from ocean aerosols, was negatively related to oligotrophic species and positively to nitrophytic. - Causes of change in nitrophytic and oligotrophic lichen species.

Causes of change in nitrophytic and oligotrophic lichen species in a Mediterranean climate: Impact of land cover and atmospheric pollutants

International Nuclear Information System (INIS)

Pinho, P.; Augusto, S.; Martins-Loucao, M.A.; Pereira, M.J.; Soares, A.; Maguas, C.; Branquinho, C.

2008-01-01

With the aim of determining the main drivers of changes in nitrophytic and oligotrophic macro-lichen communities in an industrial region with a Mediterranean climate, we considered both land-cover types and atmospheric pollutants. We determined the relation between the abundance of nitrophytic and oligotrophic species with environmental factors considering the distance of influence of land-cover types. The results showed that oligotrophic species decreased in the proximity of artificial areas, barren land and agricultural areas, associated with higher concentrations of NO 2 and Zn, and Ti, probably dust of industrial and agricultural origin. Nitrophytic species were positively related to all the mentioned land-cover types, and with higher concentrations of Fe and N. Magnesium, probably from ocean aerosols, was negatively related to oligotrophic species and positively to nitrophytic. - Causes of change in nitrophytic and oligotrophic lichen species

Effect of Groundwater Abstraction on Fen Ecosystems

DEFF Research Database (Denmark)

Johansen, Ole; Pedersen, Morten Lauge; Jensen, Jacob Birk

2011-01-01

within a distance of 1.5 km to a planned well field. In the river valley the interaction between groundwater and surface water is strongly affected by low permeable sediments. These sediments reduce the direct discharge to the river and have a large impact on the functioning and presence of the rich fen......Quantifying the effects of groundwater abstraction on fen ecosystems located in discharge areas can be complicated. The water level in fens is close to the terrain surface most of the year and it is controlled by a relatively constant groundwater exfiltration. It is difficult to measure...... the exfiltration fluxes and thus water level data is typically used to evaluate if the ecosystem is affected. The paper presents collected data and analysis from a case study, where the hydrological effect of groundwater abstraction on rich fens and springs in a Danish river valley has been studied. The natural...

Plankton networks driving carbon export in the oligotrophic ocean

Science.gov (United States)

Larhlimi, Abdelhalim; Roux, Simon; Darzi, Youssef; Audic, Stephane; Berline, Léo; Brum, Jennifer; Coelho, Luis Pedro; Espinoza, Julio Cesar Ignacio; Malviya, Shruti; Sunagawa, Shinichi; Dimier, Céline; Kandels-Lewis, Stefanie; Picheral, Marc; Poulain, Julie; Searson, Sarah; Stemmann, Lars; Not, Fabrice; Hingamp, Pascal; Speich, Sabrina; Follows, Mick; Karp-Boss, Lee; Boss, Emmanuel; Ogata, Hiroyuki; Pesant, Stephane; Weissenbach, Jean; Wincker, Patrick; Acinas, Silvia G.; Bork, Peer; de Vargas, Colomban; Iudicone, Daniele; Sullivan, Matthew B.; Raes, Jeroen; Karsenti, Eric; Bowler, Chris; Gorsky, Gabriel

2015-01-01

The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterised. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria, alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of just a few bacterial and viral genes can predict most of the variability in carbon export in these regions. PMID:26863193

Plankton networks driving carbon export in the oligotrophic ocean

Science.gov (United States)

2016-04-01

The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterized. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria and alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of a few bacterial and viral genes can predict a significant fraction of the variability in carbon export in these regions.

Fe-N co-doped SiO2@TiO2 yolk-shell hollow nanospheres with enhanced visible light photocatalytic degradation

Science.gov (United States)

Wan, Hengcheng; Yao, Weitang; Zhu, Wenkun; Tang, Yi; Ge, Huilin; Shi, Xiaozhong; Duan, Tao

2018-06-01

SiO2@TiO2 yolk@shell hollow nanospheres (STNSs) is considered as an outstanding photocatalyst due to its tunable structure and composition. Based on this point, we present an unprecedentedly excellent photocatalytic property of STNSs toward tannic acid via a Fe-N co-doped strategy. Their morphologies, compositions, structure and properties are characterized. The Fe-N co-doped STNSs formed good hollow yolk@shell structure. The results show that the energy gap of the composites can be downgraded to 2.82 eV (pure TiO2 = 3.2 eV). Photocatalytic degradation of tannic acid (TA, 30 mg L-1) under visible light (380 nm TiO2 nanospheres, non-doped STNSs and N-doped STNSs, the Fe-N co-doped STNSs exhibits the highest activity, which can degrade 99.5% TA into CO2 and H2O in 80 min. The probable degradation mechanism of the composites is simultaneously proposed, the band gap of STNSs becomes narrow by co-doping Fe-N, so that the TiO2 shell can stimulate electrons under visible light exposure, generate the ions of radOH and radO2- with a strong oxidizing property. Therefore this approach works is much desired for radioactive organic wastewater photocatalytic degradation.

Characteristics and ontogeny of oligotrophic hardwater lakes in the Forsmark area, central Sweden

Energy Technology Data Exchange (ETDEWEB)

Brunberg, A.K.; Blomqvist, P. [Uppsala Univ. (Sweden). Dept. of Limnology

1999-12-01

colonise the littoral, and a mire is formed around the lake. In later stages of succession, Sphagnum becomes more and more dominant in the system, which successively turns acidic. The final stage of the ontogeny is likely to be a raised bog ecosystem with an autonomous hydrological functioning. A tentative model for a mature hardwater lake has been created, indicating how and where substances from the drainage area may be accumulated in the system. Depending on the (unknown) hydrology of the lake basin, accumulation of substances can either take place in the Sphagnum littoral, in the illuminated soft-bottom sediments or in both these habitats. Processes in the open water will be of less importance in the system, since production of organisms in that habitat is most likely low. However, fish may act as a pump for nutrients and organic matter between the soft-bottom and the open water habitats, thereby disturbing the accumulation of substances in the sediments. In conclusion, several pieces are lacking to complete the picture of the structure and functioning of the ecosystem in the oligotrophic hardwater lakes of the Forsmark area. Research directed towards the understanding of the lakes as a trap for contaminants should be focused on the hydrology of the basin and on the basal production in two of the key habitats; the mire/floating littoral system and the 'microbial mat' in the light exposed soft bottom areas.

Characteristics and ontogeny of oligotrophic hardwater lakes in the Forsmark area, central Sweden

International Nuclear Information System (INIS)

Brunberg, A.K.; Blomqvist, P.

1999-12-01

colonise the littoral, and a mire is formed around the lake. In later stages of succession, Sphagnum becomes more and more dominant in the system, which successively turns acidic. The final stage of the ontogeny is likely to be a raised bog ecosystem with an autonomous hydrological functioning. A tentative model for a mature hardwater lake has been created, indicating how and where substances from the drainage area may be accumulated in the system. Depending on the (unknown) hydrology of the lake basin, accumulation of substances can either take place in the Sphagnum littoral, in the illuminated soft-bottom sediments or in both these habitats. Processes in the open water will be of less importance in the system, since production of organisms in that habitat is most likely low. However, fish may act as a pump for nutrients and organic matter between the soft-bottom and the open water habitats, thereby disturbing the accumulation of substances in the sediments. In conclusion, several pieces are lacking to complete the picture of the structure and functioning of the ecosystem in the oligotrophic hardwater lakes of the Forsmark area. Research directed towards the understanding of the lakes as a trap for contaminants should be focused on the hydrology of the basin and on the basal production in two of the key habitats; the mire/floating littoral system and the 'microbial mat' in the light exposed soft bottom areas

Impacts of oil sands process water on fen plants: Implications for plant selection in required reclamation projects

International Nuclear Information System (INIS)

Pouliot, Rémy; Rochefort, Line; Graf, Martha D.

2012-01-01

Fen plant growth in peat contaminated with groundwater discharges of oil sands process water (OSPW) was assessed in a greenhouse over two growing seasons. Three treatments (non-diluted OSPW, diluted OSPW and rainwater) were tested on five vascular plants and four mosses. All vascular plants tested can grow in salinity and naphthenic acids levels currently produced by oil sands activity in northwestern Canada. No stress sign was observed after both seasons. Because of plant characteristics, Carex species (C. atherodes and C. utriculata) and Triglochin maritima would be more useful for rapidly restoring vegetation and creating a new peat-accumulating system. Groundwater discharge of OSPW proved detrimental to mosses under dry conditions and ensuring adequate water levels would be crucial in fen creation following oil sands exploitation. Campylium stellatum would be the best choice to grow in contaminated areas and Bryum pseudotriquetrum might be interesting as it has spontaneously regenerated in all treatments. - Highlights: ► Fen plant growth was assessed under groundwater discharges of oil sands process water. ► Sedge and grass species were not stressed after two growing seasons in greenhouse. ► Carex species and Triglochin maritima would be helpful in created contaminated fens. ► In dry conditions, contaminated groundwater discharge was detrimental for mosses. ► Campylium stellatum would be the best choice in created fens with contaminated water. - Sedges and grasses tolerated the contact with oil sands process water and could probably grow well in contaminated created fens, but mosses were particularly affected under dry conditions.

A caveat regarding diatom-inferred nitrogen concentrations in oligotrophic lakes

Science.gov (United States)

Arnett, Heather A.; Saros, Jasmine E.; Mast, M. Alisa

2012-01-01

Atmospheric deposition of reactive nitrogen (Nr) has enriched oligotrophic lakes with nitrogen (N) in many regions of the world and elicited dramatic changes in diatom community structure. The lakewater concentrations of nitrate that cause these community changes remain unclear, raising interest in the development of diatom-based transfer functions to infer nitrate. We developed a diatom calibration set using surface sediment samples from 46 high-elevation lakes across the Rocky Mountains of the western US, a region spanning an N deposition gradient from very low to moderate levels (phosphorus, and hypolimnetic water temperature were related to diatom distributions. A transfer function was developed for nitrate and applied to a sedimentary diatom profile from Heart Lake in the central Rockies. The model coefficient of determination (bootstrapping validation) of 0.61 suggested potential for diatom-inferred reconstructions of lakewater nitrate concentrations over time, but a comparison of observed versus diatom-inferred nitrate values revealed the poor performance of this model at low nitrate concentrations. Resource physiology experiments revealed that nitrogen requirements of two key taxa were opposite to nitrate optima defined in the transfer function. Our data set reveals two underlying ecological constraints that impede the development of nitrate transfer functions in oligotrophic lakes: (1) even in lakes with nitrate concentrations below quantification (<1 μg L−1), diatom assemblages were already dominated by species indicative of moderate N enrichment; (2) N-limited oligotrophic lakes switch to P limitation after receiving only modest inputs of reactive N, shifting the controls on diatom species changes along the length of the nitrate gradient. These constraints suggest that quantitative inferences of nitrate from diatom assemblages will likely require experimental approaches.

Extração, análise e distribuição dos ácidos fenólicos em genótipos pigmentados e não pigmentados de arroz (Oryza sativa L. Extraction, analysis and distribution of phenolic acids in pigmented and non-pigmented genotypes of rice (Oryza sativa L.

Directory of Open Access Journals (Sweden)

Nádia Valéria Mussi de Mira

2008-12-01

Full Text Available Neste estudo, avaliaram-se a distribuição dos Compostos Fenólicos Totais (CFT e o perfil de ácidos fenólicos, presentes nas frações, solúvel e insolúvel de dez genótipos de arroz (Oryza sativa L. de pericarpo pigmentado e não pigmentado. Devido à sua elevada capacidade antioxidante, os compostos fenólicos vem sendo apontados como possíveis promotores da saúde. Grande parte corresponde aos ácidos fenólicos presentes no grão sob a forma solúvel (livre e conjugada e insolúvel (ligada. Na literatura há poucas informações sobre a contribuição dos compostos fenólicos ligados, cujos teores são costumeiramente subestimados. Os CFT foram quantificados pelo método de Folin-Ciocalteau, enquanto os ácidos fenólicos por RP-HPLC. Na fração solúvel dos genótipos pigmentados, os teores de CFT foram variáveis, mas, em média, 5,7 vezes maiores do que nos não pigmentados (média de 3468 e 602 µg eq. Ácido Ferúlico (AF/g arroz, respectivamente, principalmente devido à presença de antocianinas e proantocianidinas. Na fração insolúvel, os pigmentados apresentaram duas vezes mais CFT do que os não pigmentados (825 e 378 µg eq. AF/g arroz, respectivamente, provavelmente devido à retenção de antocianinas e proantocianidinas, mesmo após cinco extrações consecutivas. Dentre os ácidos fenólicos, o ácido ferúlico foi o principal componente em todos os genótipos estudados, exceto no arroz preto, no qual predominou o ácido protocatecóico.This study was conducted to evaluate the distribution of total phenolic compounds and phenolic acids in the soluble and insoluble fractions of 10 rice (Oryza sativa L. genotypes with pigmented or non-pigmented pericarp. These compounds were reported to exert beneficial effects on human health due to their high antioxidant activities. The total phenolic compounds (CFT in both fractions was determined by the Folin-Ciocalteau method and phenolic acids RP-HPLC with Diode-Array Detection

Responses of fen plant species to groundwater level and light intensity

NARCIS (Netherlands)

Kotowski, W; van Andel, J; van Diggelen, R; Hogendorf, J.

Characteristic species of sedge-moss fen communities occur in constantly wet, nutrient-poor sites with a high penetration of light through the vegetation canopy. We studied the effects of water table depth and differences in light intensity on the performance of fen species. Three fen species (Carex

Carbon budget of oligotrophic mires in the Southern Taiga of Western Siberia under anthropogenic impact

Science.gov (United States)

Golovatskaya, Eugenia; Dyukarev, Egor

2010-05-01

Role of peatlands in the global greenhouse gases budget is highly relevant. According to present estimates peatlands in undisturbed conditions act as a sink for the atmospheric carbon. Anthropogenic impact on peatlands (melioration, changes in land use, influence of underground water catchments) results in water table lowering, changing in vegetation cover, and degradation of peat deposit. Peatlands could provide a significant positive feedback for climate changes if warming and peatlands drying stimulates bulk soil organic matter decomposition which enhances CO2 release to the atmosphere. Western Siberian peatlands usually represented big bog massifs. Big peatlands have higher stability to external influence. Small peatlands have all signs of big bogs but react on changes in environmental variables more quickly. The present study is devoted to investigation of primary carbon fluxes (CO2 emission and net primary productivity) and carbon balance at oligotrophic bogs in native condition (key area "Bakchar") and under anthropogenic impact (key area "Ob'-Tom'"). The key area "Bakchar" is located between the Iksa and Bakchar rivers (56o58`N 82o36`E) at the Bakcharskoe bog (area 1400 km2). The key area "Ob'-Tom'"is located in the northern part of Ob' and Tom' interfluve (56o21`N 82o31`E). The "Bakchar" key area includes the following ecosystems: pine- shrub-sphagnum community, a similar community with stunted (low) pine trees, and sedge-sphagnum fen. Two small peatlands were studied at Ob' and Tom' interfluve. Kirsanovskoe bog includes pine- shrub-sphagnum community and sedge fen. Timiryazevskoe bog was represented by pine- shrub-sphagnum (TPSS) community and sedge fen. An infrared gas analyzer OPTOGAS 500.4 (OPTEC Corp., St.-Petersburg, Russia) attached to a static opaque plastic been used for carbon dioxide emission measurements. The net primary productivity was measured by clipping method (Golovatskaya and Dyukarev, Plant Soil 2009). Peatlands at "Ob'-Tom'" key area

Understanding the Groundwater Hydrology of a Geographically-Isolated Prairie Fen: Implications for Conservation.

Science.gov (United States)

Sampath, Prasanna Venkatesh; Liao, Hua-Sheng; Curtis, Zachary Kristopher; Doran, Patrick J; Herbert, Matthew E; May, Christopher A; Li, Shu-Guang

2015-01-01

The sources of water and corresponding delivery mechanisms to groundwater-fed fens are not well understood due to the multi-scale geo-morphologic variability of the glacial landscape in which they occur. This lack of understanding limits the ability to effectively conserve these systems and the ecosystem services they provide, including biodiversity and water provisioning. While fens tend to occur in clusters around regional groundwater mounds, Ives Road Fen in southern Michigan is an example of a geographically-isolated fen. In this paper, we apply a multi-scale groundwater modeling approach to understand the groundwater sources for Ives Road fen. We apply Transition Probability geo-statistics on more than 3000 well logs from a state-wide water well database to characterize the complex geology using conditional simulations. We subsequently implement a 3-dimensional reverse particle tracking to delineate groundwater contribution areas to the fen. The fen receives water from multiple sources: local recharge, regional recharge from an extensive till plain, a regional groundwater mound, and a nearby pond. The regional sources deliver water through a tortuous, 3-dimensional "pipeline" consisting of a confined aquifer lying beneath an extensive clay layer. Water in this pipeline reaches the fen by upwelling through openings in the clay layer. The pipeline connects the geographically-isolated fen to the same regional mound that provides water to other fen clusters in southern Michigan. The major implication of these findings is that fen conservation efforts must be expanded from focusing on individual fens and their immediate surroundings, to studying the much larger and inter-connected hydrologic network that sustains multiple fens.

Homologous regions of Fen1 and p21Cip1 compete for binding to the same site on PCNA: a potential mechanism to co-ordinate DNA replication and repair.

Science.gov (United States)

Warbrick, E; Lane, D P; Glover, D M; Cox, L S

1997-05-15

Following genomic damage, the cessation of DNA replication is co-ordinated with onset of DNA repair; this co-ordination is essential to avoid mutation and genomic instability. To investigate these phenomena, we have analysed proteins that interact with PCNA, which is required for both DNA replication and repair. One such protein is p21Cip1, which inhibits DNA replication through its interaction with PCNA, while allowing repair to continue. We have identified an interaction between PCNA and the structure specific nuclease, Fen1, which is involved in DNA replication. Deletion analysis suggests that p21Cip1 and Fen1 bind to the same region of PCNA. Within Fen1 and its homologues a small region (10 amino acids) is sufficient for PCNA binding, which contains an 8 amino acid conserved PCNA-binding motif. This motif shares critical residues with the PCNA-binding region of p21Cip1. A PCNA binding peptide from p21Cip1 competes with Fen1 peptides for binding to PCNA, disrupts the Fen1-PCNA complex in replicating cell extracts, and concomitantly inhibits DNA synthesis. Competition between homologous regions of Fen1 and p21Cip1 for binding to the same site on PCNA may provide a mechanism to co-ordinate the functions of PCNA in DNA replication and repair.

Calcareous Fens - Source Feature Points

Data.gov (United States)

Minnesota Department of Natural Resources — Pursuant to the provisions of Minnesota Statutes, section 103G.223, this database contains points that represent calcareous fens as defined in Minnesota Rules, part...

Specific-activity and concentration model applied to cesium movement in an oligotrophic lake

International Nuclear Information System (INIS)

Vanderploeg, H.A.; Booth, R.S.; Clark, F.H.

1975-01-01

A linear systems-analysis model was derived to simulate the time-dependent dynamics of specific activity and concentration of radionuclides in aquatic systems. Transfer coefficients were determined for movement of 137 Cs in the components of an oligotrophic lake. These coefficients were defined in terms of basic environmental and ecological data so that the model can be applied to a wide variety of sites. Simulations with a model that ignored sediment--water interactions predicted much higher 137 Cs specific activities in the lake water and biota than did those with the complete model. Comparing 137 Cs concentrations predicted by the model with concentrations reported for the biota of an experimentally contaminated oligotrophic lake indicated that the transfer coefficients derived for the biota are adequate

Conversion of hydroxycinnamic acids into volatile phenols in a synthetic medium and in red wine by Dekkera bruxellensis Transformação de ácidos hidroxicinâmicos em fenóis voláteis em meio sintético e em vinho tinto por Dekkera bruxellensis

Directory of Open Access Journals (Sweden)

Maria João Cabrita

2012-03-01

Full Text Available The conversion of p-coumaric acid, ferulic acid, and caffeic acid into 4-ethylphenol, 4-ethylguaiacol and 4-ethylcatechol was studied in Dekkera bruxellensis ISA 1791 under defined conditions in a synthetic medium and in a red wine. Liquid chromatography (HPLC-DAD was used to quantify the phenolic acids, and gas chromatography (GC coupled to a FID detector was used to quantify volatile phenols using a novel analytical methodology that does not require sample derivatization. Identification was achieved by gas chromatography-mass detection (GC-MS. The results show that phenolic acids concentration decreases while volatile phenols concentration increases. The proportion of caffeic acid taken up by Dekkera bruxellensis is lower than that for p-coumaric or ferulic acid; therefore less 4-ethylcatechol is formed. More important, 4-ethylcathecol synthesis by Dekkera bruxellensis in wine has never been demonstrated so far. These results contribute decisively to a better understanding of the origin of the volatile phenols in wines. The accumulation of these compounds in wine is nowadays regarded as one of the key factors of quality control.A transformação do ácido p-cumárico, ácido ferúlico e ácido cafeico em 4-etilfenol, 4-etilguaiacol e 4-etilcatecol foi estudada na presença de Dekkera bruxelensis ISA 1791, sob condições controladas, em meio sintético e em vinho tinto. Os compostos fenólicos foram doseados por cromatografia em fase líquida (HPLC-DAD e os fenóis voláteis foram doseados por cromatografia em fase gasosa (GC com detector de ionização de chama (FID, recorrendo a uma metodologia que não requer prévia derivatização da amostra. A identificação dos compostos foi comprovada por espectrometria de massa (GC-MS. Os resultados demonstram que os teores em ácidos fenólicos diminuem enquanto se observa um aumento dos teores em fenóis voláteis. O ácido cafeico é dos três ácidos em estudo, o menos utilizado pela levedura, da

Fens and their rare plants in the Beartooth Mountains, Shoshone National Forest, Wyoming

Science.gov (United States)

Bonnie Heidel; Walter Fertig; Sabine Mellmann-Brown; Kent E. Houston; Kathleen A. Dwire

2017-01-01

Fens are common wetlands in the Beartooth Mountains on the Shoshone National Forest, Clarks Fork Ranger District, in Park County, Wyoming. Fens harbor plant species found in no other habitats, and some rare plants occurring in Beartooth fens are found nowhere else in Wyoming. This report summarizes the studies on Beartooth fens from 1962 to 2009, which have contributed...

Lake level fluctuations boost toxic cyanobacterial "oligotrophic blooms".

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Cristiana Callieri

Full Text Available Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena, a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D. lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D. lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms.

Formalized classification of European fen vegetation at the alliance level

DEFF Research Database (Denmark)

Peterka, Tomáš; Hájek, Michal; Jiroušek, Martin

2017-01-01

Aims Phytosociological classification of fen vegetation (Scheuchzerio palustris-Caricetea fuscae class) differs among European countries. Here we propose a unified vegetation classification of European fens at the alliance level, provide unequivocal assignment rules for individual vegetation plot...

Bivalve nutrient cycling : nutrient turnover by suspended mussel communities in oligotrophic fjords

NARCIS (Netherlands)

Jansen, H.M.

2012-01-01

This study examined a range of eco-physiological processes (i.e filtration, growth, excretion,

faeces production) and feedback mechanisms with the aim to investigate the contribution of

suspended mussel Mytilus edulis communities to nutrient cycling in oligotrophic

The hydrological functioning of a constructed fen wetland watershed.

Science.gov (United States)

Ketcheson, Scott J; Price, Jonathan S; Sutton, Owen; Sutherland, George; Kessel, Eric; Petrone, Richard M

2017-12-15

Mine reclamation requires the reconstruction of entire landforms and drainage systems. The hydrological regime of reclaimed landscapes will be a manifestation of the processes operating within the individual landforms that comprise it. Hydrology is the most important process regulating wetland function and development, via strong controls on chemical and biotic processes. Accordingly, this research addresses the growing and immediate need to understand the hydrological processes that operate within reconstructed landscapes following resource extraction. In this study, the function of a constructed fen watershed (the Nikanotee Fen watershed) is evaluated for the first two years following construction (2013-2014) and is assessed and discussed within the context of the construction-level design. The system design was capable of sustaining wet conditions within the Nikanotee Fen during the snow-free period in 2013 and 2014, with persistent ponded water in some areas. Evapotranspiration dominated the water fluxes from the system. These losses were partially offset by groundwater discharge from the upland aquifer, which demonstrated strong hydrologic connectivity with the fen in spite of most construction materials having lower than targeted saturated hydraulic conductivities. However, the variable surface infiltration rates and thick placement of a soil-capping layer constrained recharge to the upland aquifer, which remained below designed water contents in much of the upland. These findings indicate that it is possible to engineer the landscape to accommodate the hydrological functions of a fen peatland following surface oil sands extraction. Future research priorities should include understanding the storage and release of water within coarse-grained reclaimed landforms as well as evaluating the relative importance of external water sources and internal water conservation mechanisms for the viability of fen ecosystems over the longer-term. Copyright © 2017 Elsevier B

Characterization of Fen-Daqu Through Multivariate Statistical Analysis of H-1 NMR Spectroscopic Data

NARCIS (Netherlands)

Van-Diep, L.; Zheng, X.; Ma, K.; Chen, J.Y.; Han, B.Z.; Nout, M.J.R.

2011-01-01

J. Inst. Brew. 117(4), 516-522, 2011 Fen liquor is typical of Chinese light-flavour liquor (alcoholic spirit), which is fermented from sorghum with Fen-Daqu powder. Fen-Daqu is a saccharifying agent and fermentation starter in this fermentation process and in Fen traditional vinegar. To investigate

Ecology of aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

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D. Lamy

2011-04-01

Full Text Available Aerobic anoxygenic phototrophic (AAP bacteria are photoheterotrophic prokaryotes able to use both light and organic substrates for energy production. They are widely distributed in coastal and oceanic environments and may contribute significantly to the carbon cycle in the upper ocean. To better understand questions regarding links between the ecology of these photoheterotrophic bacteria and the trophic status of water masses, we examined their horizontal and vertical distribution and the effects of nutrient additions on their growth along an oligotrophic gradient in the Mediterranean Sea. Concentrations of bacteriochlorophyll-a (BChl-a and AAP bacterial abundance decreased from the western to the eastern basin of the Mediterranean Sea and were linked with concentrations of chlorophyll-a, nutrient and dissolved organic carbon. Inorganic nutrient and glucose additions to surface seawater samples along the oligotrophic gradient revealed that AAP bacteria were nitrogen- and carbon-limited in the ultraoligotrophic eastern basin. The intensity of the AAP bacterial growth response generally differed from that of the total bacterial growth response. BChl-a quota of AAP bacterial communities was significantly higher in the eastern basin than in the western basin, suggesting that reliance on phototrophy varied along the oligotrophic gradient and that nutrient and/or carbon limitation favors BChl-a synthesis.

El fenómeno de envejecimiento de los asfaltos

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Xiomara Vargas

2010-09-01

Full Text Available En este trabajo se presenta una revisión actualizada a los resultados del estudio de los procesos de envejecimiento de los asfaltos, encontrados por diversos investigadores, con el fin de profundizar en la comprensión de este fenómeno complejo. Los antecedentes demuestran la evolución del estudio del fenómeno de envejecimiento de los asfaltos, considerado inicialmente como un proceso de endurecimiento físico y progresivamente reconocido como un fenómeno complejo con repercusiones en la durabilidad y las propiedades fisicoquímicas del asfalto. Este documento pretende ser una guía para el emprendimiento de futuras investigaciones relacionadas con el desarrollo de nuevos asfaltos y mezclas asfálticas con propiedades mejoradas.

Determination of natural organic matter and iron binding capacity in fen samples

Science.gov (United States)

Kügler, Stefan; Cooper, Rebecca E.; Frieder Mohr, Jan; Wichard, Thomas; Küsel, Kirsten

2017-04-01

Natural organic matter (NOM) plays an important role in ecosystem processes such as soil carbon stabilization, nutrient availability and metal complexation. Iron-NOM-complexes, for example, are known to increase the solubility and, as a result, the bioavailability of iron in natural environments leading to several effects on the microbial community. Due to the various functions of NOM in natural environments, there is a high level of interest in the characterization of the molecular composition. The complexity of NOM presents a significant challenge in the elucidation of its composition. However, the development and utilization of high resolution mass spectrometry (HR-MS) as a tool to detect single compounds in complex samples has spearheaded the effort to elucidate the composition of NOM. Over the past years, the accuracy of ion cyclotron- or Orbitrap mass spectrometers has increased dramatically resulting in the possibility to obtain a mass differentiation of the large number of compounds in NOM. Together these tools provide significant and powerful insight into the molecular composition of NOM. In the current study, we aim to understand abiotic and biotic interactions between NOM and metals, such as iron, found in the Schlöppnerbrunnen fen (Fichtelgebirge, Germany) and how these interactions impact the microbial consortia. We characterized the dissolved organic matter (DOM) as well as basic chemical parameters in the iron-rich (up to 20 mg (g wt peat)-1), slightly acidic (pH 4.8) fen to gain more information about DOM-metal interactions. This minerotrophic peatland connected to the groundwater has received Fe(II) released from the surrounding soils in the Lehstenbach catchment. Absorption spectroscopy (AAS), differential pulse polarography (DPP) and high resolution electrospray ionization mass spectrometry (HR-ESI-Orbitrap-MS) was applied to characterize the molecular composition of DOM in the peat water extract (PWE). We identified typical patterns for DOM

Stand structure and vegetation dynamics of a subalpine treed fen in Rocky Mountain National Park, Colorado

Energy Technology Data Exchange (ETDEWEB)

Johnson, J.B. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Biology

1997-06-01

The tree population size structure and relationship between tree diameter and age were examined in a subalpine fen and surrounding Picea-Abies forest in northern Colorado. The fen grades from a sedge fen, through an ecotone, to a treed fen (i.e. fen colonized by trees). Tree growth rate varies across the vegetational gradient, with the sedge fen having the slowest growth, and the upland forest having the fastest growth. Differences in growth rate are related to the average size of peat hummocks, with areas containing tall hummocks exhibiting the highest tree growth rates. Size structures display the characteristic reverse-J distribution generally indicative of stable populations, but forest vegetation is expanding into the open regions of the fen, and within the treed fen an increase in Abies lasiocarpa is occurring. These changes are primarily attributed to a positive feedback situation wherein the fen`s surface is built up by peat accumulation. Distinct hummocks form first on the open fen but then coalesce to form raised peat islands in the treed fen. This new substrate provides habitat with a comparatively low water table and allows the growth of mesophytic forest vegetation. A pathway for this vegetational development is proposed. 40 refs., 2 figs.

Characterization of volatile compounds in Fen-Daqu - a traditional Chinese liquor fermentation starter

NARCIS (Netherlands)

Van-Diep, L.; Zheng, X.; Chen, J.Y.; Han, B.Z.

2012-01-01

Fen-Daqu is a saccharifying agent and fermentation starter for the production of Chinese liquor Fen (alcoholic spirit) and Fen traditional vinegar. The volatile compounds produced at seven incubation steps were analysed by HS-SPME-GC-MS. A total of 83 major volatile compounds were identified,

Novel fen ecosystems in western North Carolina

Science.gov (United States)

Wilcox, J. D.

2012-12-01

Western North Carolina is mountainous, and groundwater flows from hillslope recharge zones to valley stream and spring discharge zones. Depending on surface topography and geologic conditions, the water table may approach or intersect the ground surface to form seepage wetlands, or fens. Fen ecosystems can be very sensitive to changes in land use, groundwater pumping, and upslope development. This presentation will focus on two sites where historical land use and human activity played important roles in creating or preserving fen ecosystems. Both sites now support—and are being managed to protect—federally endangered flora and fauna. The first site is home to Sarracenia oreophilia, an endangered pitcher plant that thrives on saturated soils with low nutrient content. The site's early history includes tree clearing, drain tile installation, and cattle grazing, while more recent management activities have included drain tile excavation, manual invasive removal, and prescribed burns. A 15-year water-level record indicates seasonal artesian conditions wet a 3m clay unit (K=2E-5 cm/sec) beneath the site, which is able to retain moisture during drier periods. Shorter "clay wetting periods" during drought years (1999-2000; 2007-2008) correspond to reduced clump counts in pitcher-plant surveys. The second site is a former aggregate quarry that now supports over 60 bog turtles (Clemmys muhlenbergii). The biggest threat to this site is encroachment of non-native and invasive multiflora rose (Rosa multiflora) and other large woody species. Management activities include manual removal and prescribed goat herbivory. Current efforts to characterize the springs, water-table, and surface-water flows will be used to detect changes in the future to the hydrologic regime in the fen.

Brevibacterium siliguriense sp nov., a facultatively oligotrophic bacterium isolated from river water

NARCIS (Netherlands)

Kumar, A.; Ince, I.A.; Kati, A.; Chakraborty, R.

2013-01-01

A Gram-positive-staining, rod-shaped, facultatively oligotrophic bacterial strain, designated MB18(T), was isolated from a water sample collected from the River Mahananda at Siliguri (26 degrees 44' 23.20' N, 88 degrees 25' 22.89' a West-Bengal, India. On the basis of 16S rRNA gene sequence

BOREAS TF-10 NSA-Fen Tower Flux and Meteorological Data

Science.gov (United States)

McCaughey, J. Harry; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Jelinski, Dennis E.

2000-01-01

The BOREAS TF-10 team collected tower flux and meteorological data at two sites, a fen and a young jack pine forest, near Thompson, Manitoba, Canada, as part of BOREAS. A preliminary data set was assembled in August 1993 while field testing the instrument packages, and at both sites data were collected from 15-Aug to 31-Aug. The main experimental period was in 1994, when continuous data were collected from 08-Apr to 23-Sep at the fen site. A very limited experiment was run in the spring/ summer of 1995, when the fen site tower was operated from 08-Apr to 14-Jun in support of a hydrology experiment in an adjoining feeder basin. Upon examination of the 1994 data set, it became clear that the behavior of the heat, water, and carbon dioxide fluxes throughout the whole growing season was an important scientific question, and that the 1994 data record was not sufficiently long to capture the character of the seasonal behavior of the fluxes. Thus, the fen site was operated in 1996 in order to collect data from spring melt to autumn freeze-up. Data were collected from 29-Apr to 05-Nov at the fen site. All variables are presented as 30-minute averages. The data are stored in tabular ASCII files.

Fenómeno de Raynaud. Revisión

OpenAIRE

Jairo Alonso Rodríguez-Criollo; Daniel Jaramillo-Arroyave

2014-01-01

El fenómeno de Raynaud es una respuesta vascular exagerada al frio o al estrés que se manifiesta por cambios de coloración de la piel en diversas localizaciones, característicamente mostrando tres fases distintas que comprenden palidez, cianosis y rubor. La fisiopatología tiene varios componentes y puede tener varias etiologías, que comprenden vasoconstricción, agregación plaquetaria, trombosis y proliferación vascular. Dependiendo de la ausencia o la presencia de enfermedad de base, el fenóm...

Understanding toxicity at the watershed scale : design of the Syncrude Sandhill Fen watershed research project

International Nuclear Information System (INIS)

Wytrykush, C.

2010-01-01

Fens are peat-accumulating wetlands with a water table consisting of mineral-rich ground or surface water. This study discussed the construction of a fen-type reclaimed wetland constructed in a post-mining oil sands landscape. Syncrude Canada's Sandhill fen watershed project represents the first attempt at constructing a fen wetland in the oil sands region. The wetland and its watershed will be constructed on a soft tailings deposit. The design basis for the fen and watershed was developed by a team of researchers and scientists. The aim of the fen design was to control the salinity caused by tailings consolidation and seepage over time. Methods of mitigating potentially toxic effects from salinity were discussed.

Post-fire regeneration of vegetation on sandy oligotrophic soil, in Itabaiana, Sergipe, Brazil

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Túlio Vinicius Paes Dantas

2015-07-01

Full Text Available Two models of post-disturbance regeneration of vegetation in areas of oligotrophic soils have been proposed for temperate regions. The first model is characterized by rapid recovery of the floristic composition, due to the fire resistance of plants; while in the second model, the fire causes extensive mortality and the recovery occurs by recruitment from the seed bank. Since these models have been rarely tested in tropical oligotrophic environments, we applied them in the analysis of floristic compositions in three areas with different post-fire regeneration times in Sergipe State, Brazil. The regeneration followed the seed bank recruitment model in places of bare ground, with a progressive increase in plant density and changes in the relative abundance and dominance of the populations along the successional process. The parameters that best allowed the succession evaluation were the floral similarity, plant height and density, which increased as regeneration progressed. The stem diameter and tillering were inconclusive as parameters for assessing the regeneration progress.

Water level influences on body condition of Geophagus brasiliensis (Perciformes: Cichlidae in a Brazilian oligotrophic reservoir

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Alejandra Filippo Gonzalez Neves dos Santos

Full Text Available Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K and gonadosomatic index (GSI were compared according to water level (low and high. Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad development occurred in low water. Females presented higher reproductive investment than males, which allocated most of energy for somatic development. This strategy could be a mechanism to undergo the stress caused by oligotrophic characteristics of the reservoir enhanced during low water level.

El fenómeno de bullying en Colombia

Directory of Open Access Journals (Sweden)

Ángela Paola Contreras Álvarez

2013-01-01

Full Text Available El presente artículo describe el nefasto fenómeno de violencia y hostigamiento en ambientes escolares denominado bullying o matoneo escolar, el cual, aunque ha sido analizado desde finales de los años setenta en los países escandinavos, tuvo auge en Colombia en el año 2000, adquiriendo fuerza y permanencia con el uso de redes sociales, evidenciando la falta de políticas nacionales educativas para la atención e intervención del problema, al igual que el olvido de educación en derechos humanos y resolución pacífica de conflictos en los colegios. Esta problemática se desarrolla a través del significado del bullying, la descripción de sus antecedentes, descripción general del fenómeno, relación de los deberes del Estado frente al tema, la concepción del fenómeno desde la perspectiva de la Corte Constitucional, concluyendo en algunas sugerencias para abordar la problemática escolar.

Saharan dust inputs and high UVR levels jointly alter the metabolic balance of marine oligotrophic ecosystems

Science.gov (United States)

Cabrerizo, Marco J.; Medina-Sánchez, Juan Manuel; González-Olalla, Juan Manuel; Villar-Argaiz, Manuel; Carrillo, Presentación

2016-10-01

The metabolic balance of the most extensive bioma on the Earth is a controversial topic of the global-change research. High ultraviolet radiation (UVR) levels by the shoaling of upper mixed layers and increasing atmospheric dust deposition from arid regions may unpredictably alter the metabolic state of marine oligotrophic ecosystems. We performed an observational study across the south-western (SW) Mediterranean Sea to assess the planktonic metabolic balance and a microcosm experiment in two contrasting areas, heterotrophic nearshore and autotrophic open sea, to test whether a combined UVR × dust impact could alter their metabolic balance at mid-term scales. We show that the metabolic state of oligotrophic areas geographically varies and that the joint impact of UVR and dust inputs prompted a strong change towards autotrophic metabolism. We propose that this metabolic response could be accentuated with the global change as remote-sensing evidence shows increasing intensities, frequencies and number of dust events together with variations in the surface UVR fluxes on SW Mediterranean Sea. Overall, these findings suggest that the enhancement of the net carbon budget under a combined UVR and dust inputs impact could contribute to boost the biological pump, reinforcing the role of the oligotrophic marine ecosystems as CO2 sinks.

HYDRO-ECOLOGICAL ANALYSIS OF THE FEN SYSTEM LIEPER POSSE, EASTERN GERMANY

NARCIS (Netherlands)

VANDIGGELEN, R; GROOTJANS, AP; KEMMERS, RH; KOOIJMAN, AM; SUCCOW, M; DEVRIES, NPJ; VANWIRDUM, G; Vries, N.P.J. de; Wirdum, G. van

The Lieper Posse is a calcareous, ground water-fed fen system, situated in the end-moraine area of northeastern Germany. Nowadays the fen is partly drained and the vegetation adversely affected; hence regeneration measures are considered. Here we report a pilot survey of the actual vegetation cover

Fenólicos totais e capacidade antioxidante in vitro de polpas de frutos tropicais

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Luanne Morais Vieira

2011-09-01

Full Text Available O consumo de frutos e suas polpas tem sido muito recomendado por seu valor nutricional, alto teor de fibras, vitamina C e carotenoides. Trabalhos recentes têm apontado esses alimentos como fontes de compostos fenólicos com ação antioxidante, portanto sequestradores de radicais livres, com ação protetora contra o surgimento e/ou desenvolvimento de processos degenerativos que conduzem a doenças crônicas não transmissíveis. Devido à crescente comercialização e consumo de polpas de frutas no Brasil, especialmente na cidade de Teresina-Piauí, este trabalho selecionou um grupo de polpas de frutos de elevado consumo local para avaliação do teor de fenólicos totais e da atividade antioxidante in vitro pelo método de captura de radicais livres: DPPH (radical 1,1-diphenil-2-picrilhydrazil e ABTS (radical 2,2'azinobis(3-ethylbenzthiazoline-6-sulfonic acid. Os frutos selecionados foram: Acerola (Malpighia emarginata DC., Bacuri (Platonia insignis Mart., Cajá (Spondias mombin L., Caju (Anacardium occidentale, Goiaba(Psidium guajava e Tamarindo (Tamarindus indica L.. Os teores de fenólicos totais encontrados nas polpascongeladas destes frutos exibiram quantidades relevantes de polifenóis, destacando-se a polpa de acerola com 835,25 ± 32,44 e 449,63 ± 10,24 mg /100g nos extratos aquosos e hidroalcoólicos, respectivamente, seguido pela polpa de caju com 201,61 ± 19,15 e 165,07 ± 4,10 mg /100g. As polpas de bacuri e tamarindo foram as que apresentaram os menores teores de fenólicos totais. Com relação à atividade antioxidante in vitro, os melhores resultados foram encontrados para os extratos aquosos e hidroalcoólicos das polpas de acerola, caju e goiaba. A capacidade antioxidante destas polpas (EC50 em µg/mL variou de 24,42 a 413,36 e de 1,74 a 259,18 para os extratos aquosos e hidroalcoólicos, respectivamente. Utilizando o radical ABTS, a atividade antioxidante para essas mesmas polpas de frutas apresentou valores TEAC que

Conservation and Biodiversity of Rich Fens

DEFF Research Database (Denmark)

Andersen, Dagmar Kappel

2014-01-01

Rich fen is a habitat type dependent on a constant supply of nutrient poor, calcium rich groundwater. A high, stable groundwater table, relatively high pH combined with nutrient poor conditions support a special and very species rich vegetation including many rare and threatened plant species. In...

Phytoplankton biovolume is independent from the slope of the size spectrum in the oligotrophic atlantic ocean

KAUST Repository

Moreno-Ostos, Enrique; Blanco, José Marí a; Agusti, Susana; Lubiá n, Luis M.; Rodrí guez, Valeriano; Palomino, Roberto L.; Llabré s, Moira; Rodrí guez, Jaime

2015-01-01

high phytoplankton biovolume in productive regions with flatter spectrum slope and the opposite in oligotrophic ecosystems. Rather than this, the relationship between high biovolume phytoplankton assemblages and flatter size-abundance spectra does

Fungal Diversity in a Dark Oligotrophic Volcanic Ecosystem (DOVE on Mount Erebus, Antarctica

Directory of Open Access Journals (Sweden)

Hubert Staudigel

2013-05-01

Full Text Available Fumarolic Ice caves on Antarctica’s Mt. Erebus contain a dark oligotrophic volcanic ecosystem (DOVE and represent a deep biosphere habitat that can provide insight into microbial communities that utilize energy sources other than photosynthesis. The community assembly and role of fungi in these environments remains largely unknown. However, these habitats could be relatively easily contaminated during human visits. Sixty-one species of fungi were identified from soil clone libraries originating from Warren Cave, a DOVE on Mt. Erebus. The species diversity was greater than has been found in the nearby McMurdo Dry Valleys oligotrophic soil. A relatively large proportion of the clones represented Malassezia species (37% of Basidomycota identified. These fungi are associated with skin surfaces of animals and require high lipid content for growth, indicating that contamination may have occurred through the few and episodic human visits in this particular cave. These findings highlight the importance of fungi to DOVE environments as well as their potential use for identifying contamination by humans. The latter offers compelling evidence suggesting more strict management of these valuable research areas.

Formation cross section of iron-60 with reactor neutrons in 59Fe(n, γ)60Fe reaction

International Nuclear Information System (INIS)

Sato, T.; Suzuki, T.

1993-01-01

Ingrowth of 60 Co radioactivity in an iron sample irradiated in a nuclear reactor has been measured for determination of formation cross section of 60 Fe in the 59 Fe(n, γ) 60 Fe reaction with reactor neutrons. After 5 years cooling, the irradiated iron was purified from 60 Co and other radioactive nuclides by an anion exchange separation method and isopropyl ether extraction in hydrochloric acid. The amount of 60 Co ingrowth was measured by γ-spectrometry using a Ge-detector coupled to a multichannel pulse height analyzer 4 years after the purification of iron. Neutron flux of the irradiation position was calculated from the amount of 55 Fe produced. The observed value of 12.5 ± 2.8 barn is slightly greater than reported value for burnup cross section of 59 Fe(n, x)X, where x refers γ, α, d, p and 2n, and X is any nuclide produced by the above reactions. (author) 8 refs.; 2 tabs

Examining the peat-accumulating potential of fen vegetation in the context of fed restoration of harvested peatlands

Energy Technology Data Exchange (ETDEWEB)

Graf, M.; Rochefort, L. [Laval Univ., Quebec City, PQ (Canada). Dept. de Phytologie, Peatland Ecology and Research Group

2009-07-01

The return of peat-accumulating function is an important long-term goal in peatland restoration. However, researchers do not yet know which vegetation groups increase the ability of ecosystems to accumulate peat in fens. This study assessed the decomposition rates of 3 vegetation species typical to undisturbed fen regions, and 3 species that spontaneously colonize harvested fens. All species were incubated in a harvest fen restoration site as well as at an undisturbed fen in order to compare decomposition rates according to different environmental conditions. The study showed that the average exponential decay coefficient for all species was higher at the harvested fen site. The decay coefficient varied only slightly between undisturbed and harvested fens, despite wide variations in hydrological conditions. Litter type had the most significant impact on decomposition rates. Annual primary production of the species was also measured in order to estimate the peat accumulating capacity of each species. Results showed that Scirpus cyperinus primary annual production rates were 3 times higher than the other studied species. It was concluded that the harvested fen sites have a higher peat-accumulating potential than undisturbed fens. 60 refs., 2 tabs., 2 figs.

Carbon and phosphorus regulating bacterial metabolism in oligotrophic boreal lakes

DEFF Research Database (Denmark)

Vidal, L. O.; Graneli, W.; Daniel, C. B.

2011-01-01

This study focused on how phosphorus and carbon control pelagic bacteria in lakes over a gradient of dissolved organic carbon (DOC from 6.7 to 29.5 mg C L(-1)) and phosphorus (P-tot from 5 to 19 mu g L(-1)). Five oligotrophic lakes in southern Sweden were sampled in late autumn. Phosphate...... carbon mineralization in this kind of system during autumn is conditioned by the combined availability of labile carbon and phosphorus, with the assimilated carbon mainly transformed to inorganic carbon in respiration, contributing to CO(2) supersaturation in these systems....

Decomposition of Carex and Sphagnum litter in two mesotrophic fens differing in dominant plant species

NARCIS (Netherlands)

Scheffer, R.A.; Van Logtestijn, R. S P; Verhoeven, J. T A

2001-01-01

Peatlands can be classified into fens and bogs based on their hydrology. Development of fens to bogs is accompanied by the invasion of Sphagnum species. The purpose of this study was to determine how the decomposition process in fens is influenced by the transition from a vascular plant-dominated

Compostos fenólicos totais e taninos condensados em frutas nativas do cerrado

Directory of Open Access Journals (Sweden)

Wesley Silveira Rocha

2011-12-01

Full Text Available As frutas nativas do cerrado têm despertado ultimamente interesse crescente, devido às suas propriedades nutricionais e funcionais aliadas ao potencial para agregar valor e conservar a biodiversidade deste bioma. Muitos compostos fenólicos apresentam capacidade antioxidante de neutralizar a atividade de radicais livres gerados no organismo, que estão associados a diversas doenças crônico-degenerativas. O objetivo deste trabalho foi avaliar a eficiência de três soluções extratoras (acetona a 70 %, etanol a 95 % e metanol a 99,8 % e determinar os teores de compostos fenólicos em 10 espécies de frutas nativas do cerrado, utilizando o método de Folin-Ciocalteou para compostos fenólicos totais e o método da vanilina para taninos condensados. A acetona a 70 % mostrou-se como o melhor solvente extrator de compostos fenólicos totais e taninos condensados em frutos de Pouteria gardneriana, Eugenia dysenterica, E. klostzchiana, E. punicifolia, Plinia edulis, Campomanesia sp., fenólicos totais de Brosimium gaudichaudii e taninos condensados de Jaracatia spinosa. O etanol a 95 % foi mais eficiente na extração de fenólicos totais de Jaracatia spinosa e taninos condensados de Brosimium gaudichaudii; o metanol a 99,8 % foi mais eficiente na extração de taninos condensados de Eugenia dysenterica. Os teores de compostos fenólicos totais variaram entre 90 e 327 mg de ácido gálico equivalente por 100g de polpa para as espécies E. dysenterica e E. punicifolia, respectivamente. Os teores de taninos condensados variaram entre 4 e 291 mg de catequina equivalente por 100 g de polpa para as espécies E. dysenterica e E. calcyna, respectivamente. As espécies de frutas do cerrado, avaliadas neste estudo, podem ser consideradas boas fontes de compostos fenólicos totais, sendo que a natureza específica dos diferentes tipos deve ser avaliada em estudos futuros.

Minor effects of long-term ozone exposure on boreal peatland species Eriophorum vaginatum and Sphagnum papillosum

DEFF Research Database (Denmark)

Mörsky, SK; Haapala, JK; Rinnan, Riikka

2011-01-01

The effects of long-term ozone fumigation on two common peatland plant species, a sedge Eriophorum vaginatum L. and a moss Sphagnum papillosum Lindb., were studied applying peatland microcosms. The peat cores with intact vegetation were cored from an oligotrophic pine fen and partially embedded...

Complex microbiota of a Chinese "Fen" liquor fermentation starter (Fen-Daqu), revealed by culture-dependent and culture-independent methods

NARCIS (Netherlands)

Zheng, X.; Zheng, Y.; Han, B.; Zwietering, M.H.; Samson, R.A.; Boekhout, T.; Nout, M.J.R.

2012-01-01

Daqu is a traditional fermentation starter that is used for Chinese liquor production. Although partly mechanized, its manufacturing process has remained traditional. We investigated the microbial diversity of Fen-Daqu, a starter for light-flavour liquor, using combined culture-dependent and

El concepto de fenómeno en el joven Heidegger

Directory of Open Access Journals (Sweden)

Francisco De Lara

2008-01-01

Full Text Available El presente trabajo es una discusión del concepto de fenómeno tal y como éste se encuentra determinado en la filosofía del joven Heidegger. Con ella se pretende ir a la base que permite dilucidar en qué sentido hace éste fenomenología o, en otras palabras, qué idea de filosofía se encuentra expresada bajo el título de hermenéutica fenomenológica. Al hilo de la lectura del concepto de fenómeno como concepto filosófico, esto es, como indicación formal, nos preguntaremos: 1 cómo se toma en consideración lo investigado fenomenológicamente; 2 cómo debe comparecer lo así investigado y 3 si, en efecto, el concepto de fenómeno funciona siempre en Heidegger como una indicación formal o si no puede constatarse en él una cierta ambigüedad.

Fenótipos clínicos de asma grave Clinical phenotypes of severe asthma

Directory of Open Access Journals (Sweden)

Roseliane de Souza Araújo Alves

2008-09-01

Full Text Available OBJETIVO: Estabelecer os fenótipos clínicos em portadores de asma grave. MÉTODOS: Foram estudados, retrospectivamente, 111 pacientes em um ambulatório especializado. Os pacientes foram avaliados e acompanhados de maneira sistemática, estabelecendo-se ao final do acompanhamento a adesão e o controle ou não da doença por dados clínicos e funcionais. A resistência ao tratamento foi definida como o não preenchimento, ao final do acompanhamento, por pelo menos seis meses, dos critérios de controle de asma, apesar do uso correto e adesão à medicação. Os fenótipos foram determinados por análise fatorial e comparados por testes diversos. RESULTADOS: Ao final, 88 pacientes foram considerados aderentes e 23 não aderentes. Por análise fatorial do grupo aderente, quatro fenótipos foram determinados: o fenótipo 1 (28 pacientes, formado pelos pacientes resistentes ao tratamento, com maior freqüência de sintomas noturnos, maior número de exacerbações e uso mais freqüente de broncodilatador de resgate; o fenótipo 2 (48 pacientes, formado pelos pacientes com obstrução persistente, com menores valores de relação volume expiratório forçado no primeiro segundo/capacidade vital forçada na avaliação inicial, idade mais avançada e maior tempo de doença; o fenótipo 3 (42 pacientes, representa os pacientes com rinossinusite alérgica, sendo constituído de não fumantes com obstrução predominantemente reversível; e o fenótipo 4 (15 pacientes, formado por casos com história de intolerância à aspirina associado à asma quase fatal. CONCLUSÕES: Um número significativo de portadores de ama grave não adere ao tratamento. Muitos pacientes com asma grave têm obstrução irreversível, mas o fenótipo clínico mais relevante é constituído pelos pacientes resistentes ao tratamento habitual.OBJECTIVE: To characterize clinical phenotypes of severe asthma. METHODS: A total of 111 patients were retrospectively evaluated at a

Remotely sensed hydrological isolation : a key factor predicting plant species distribution in fens

NARCIS (Netherlands)

Sanders, M.E.

1999-01-01

In fens the species composition, vegetation structure and succession rate are determined by vegetation management and water chemistry, particularly by the base status and nutrient status. Base-rich and nutrient-rich surface water causes fens to become eutrophied, which leads to an increased

Modelado lingüístico de fenómenos complejos

OpenAIRE

Álvarez Álvarez, Alberto

2012-01-01

Actualmente, es posible adquirir y almacenar grandes volúmenes de datos sobre diferentes fenómenos complejos en muchas áreas importantes. Con el fin de ser útil, esta información debe ser explicada de la manera más comprensible posible, incluyendo los conocimientos previos disponibles sobre el fenómeno que se estudia. Estos objetivos sólo pueden lograrse mediante el uso de lenguaje natural, especialmente si la información final va a ser utilizada por personas no expertas. Por lo tanto, e...

Concepts of fen and bog re-examined in relation to bryophyte cover and the acidity of surface waters

OpenAIRE

Eville Gorham; Jan A. Janssens

2014-01-01

Studies of surface-water pH and bryophyte assemblages in 440 plots from five peatland regions across northern North America reveal a very distinct, two-fold division into fens with a pH mode at 6.76-7.00, in which Amblystegiaceae are prominent, and bogs with a pH mode at 4.01-4.25, in which Sphagnaceae are dominant. The relevance of the data to past and current views on peatland classification is explored.

Concepts of fen and bog re-examined in relation to bryophyte cover and the acidity of surface waters

Directory of Open Access Journals (Sweden)

Eville Gorham

2014-01-01

Full Text Available Studies of surface-water pH and bryophyte assemblages in 440 plots from five peatland regions across northern North America reveal a very distinct, two-fold division into fens with a pH mode at 6.76-7.00, in which Amblystegiaceae are prominent, and bogs with a pH mode at 4.01-4.25, in which Sphagnaceae are dominant. The relevance of the data to past and current views on peatland classification is explored.

A preliminary carbon budget for two oligotrophic hardwater lakes in the Forsmark area, Sweden

Energy Technology Data Exchange (ETDEWEB)

Nilsson, Eva [Uppsala Univ. (Sweden). Dept. of Limnology

2001-06-01

The Swedish Nuclear Fuel and Waste Management Co (SKB) is responsible for management and disposal of Swedish radioactive waste. The company is planning to construct repositories that will keep radioactive waste away from humans for hundreds of thousands of years. In a safety assessment of the repositories hypothetical releases are used to evaluate the robustness of the repositories. It is important to know how the radioactive nuclides would react if they were released and by which way they could enter the living biota. SFR are responsible for the disposal of low radioactive waste and close to the nuclear plant in Forsmark there is a storage for low radioactive waste. At the moment this storage is located in the bedrock far below the sea level but due to land-rise in the area it will in the future be located above sea level. Hence, it is of importance to know how the surface ecosystems in the area are functioning. A carbon budget for the aquatic ecosystem above SFR in Oeresundsgrepen exist, but it is also important to have a carbon budget for the surface systems in the Forsmark area since SFR in the future will be situated above sea level. Carbon budgets can be used to get a picture of how an ecosystem functions. The carbon flow shows how carbon is transported through a food web from lower trophic levels, e.g. plants and bacteria to higher trophic levels such as fish. Oligotrophic hardwater lakes are the most important lakes in the Forsmark area. This report aims to give a picture of a potential flow of carbon through the ecosystem in two oligotrophic hard-water lakes, Lake Haellefjaerd and Lake Eckarfjaerden. Macrophyte, mainly Chara, were calculated to make up the largest part of the biomass and production in both lakes. Benthic bacteria and microphytobenthos (benthic photosynthesising microorganisms) were other large contributors to the production. Benthic bacteria were found responsible for a major part of respiration and, hence, consumption of carbon in the

A preliminary carbon budget for two oligotrophic hardwater lakes in the Forsmark area, Sweden

International Nuclear Information System (INIS)

Nilsson, Eva

2001-06-01

The Swedish Nuclear Fuel and Waste Management Co (SKB) is responsible for management and disposal of Swedish radioactive waste. The company is planning to construct repositories that will keep radioactive waste away from humans for hundreds of thousands of years. In a safety assessment of the repositories hypothetical releases are used to evaluate the robustness of the repositories. It is important to know how the radioactive nuclides would react if they were released and by which way they could enter the living biota. SFR are responsible for the disposal of low radioactive waste and close to the nuclear plant in Forsmark there is a storage for low radioactive waste. At the moment this storage is located in the bedrock far below the sea level but due to land-rise in the area it will in the future be located above sea level. Hence, it is of importance to know how the surface ecosystems in the area are functioning. A carbon budget for the aquatic ecosystem above SFR in Oeresundsgrepen exist, but it is also important to have a carbon budget for the surface systems in the Forsmark area since SFR in the future will be situated above sea level. Carbon budgets can be used to get a picture of how an ecosystem functions. The carbon flow shows how carbon is transported through a food web from lower trophic levels, e.g. plants and bacteria to higher trophic levels such as fish. Oligotrophic hardwater lakes are the most important lakes in the Forsmark area. This report aims to give a picture of a potential flow of carbon through the ecosystem in two oligotrophic hard-water lakes, Lake Haellefjaerd and Lake Eckarfjaerden. Macrophyte, mainly Chara, were calculated to make up the largest part of the biomass and production in both lakes. Benthic bacteria and microphytobenthos (benthic photosynthesising microorganisms) were other large contributors to the production. Benthic bacteria were found responsible for a major part of respiration and, hence, consumption of carbon in the

Unprecedented slow growth and mortality of the rare colonial cyanobacterium, Nostoc zetterstedtii, in oligotrophic lakes

DEFF Research Database (Denmark)

Jensen, Kaj Sand; Møller, Claus Lindskov

2011-01-01

Centimeter-large colonies of Nostoc zetterstedtii from a Swedish oligotrophic lake had the lowest growth and mortality rates of any studied temperate macrophyte. Annual growth rates at two shallow sites averaged 0.57– 0.73 3 1023 d21, corresponding to doubling times of colony dry weight in 2...

Diferentes Abordagens dos Fenômenos Subjetivos na Obra de B. F. Skinner

Directory of Open Access Journals (Sweden)

Henrique Mesquita Pompermaier

2014-08-01

Full Text Available Como a análise do comportamento aborda os fenômenos subjetivos? Seria a teoria de eventos privados a única maneira? Guiado por essas questões, o presente trabalho busca apresentar a abordagem dos fenômenos subjetivos na obra de B. F. Skinner, indicando não apenas a teoria de eventos privados, mas também a possibilidade de abordagens alternativas a essa temática, sem referência à privacidade, por exemplo, por meio da magnitude das ações envolvidas nos fenômenos, níveis (aberto e encoberto do comportamento e conceitos disposicionais. Indica-se ainda uma significativa diferença de ênfase na teoria de eventos privados ao longo da obra skinneriana. Por fim, conduz-se uma discussão sobre o papel da teoria de eventos privados na análise do comportamento para a abordagem dos fenômenos subjetivos.

Prokaryotes in subsoil – evidence for spatial separation of oligotrophs and copiotrophs by co-occurrence networks

Directory of Open Access Journals (Sweden)

Michael eSchloter

2015-11-01

Full Text Available Soil microbial communities provide a wide range of soil functions including nutrient cycling, soil formation, and plant growth promotion. On the small scale, nutrient rich soil hotspots developed from soil animal or plant activity are important drivers for microbial communities and their activity pattern. Nevertheless, in subsoil, the spatial heterogeneity of microbes with diverging lifestyles has been barely considered so far. In this study, the phylogenetic composition of the bacterial and archaeal microbiome based on 16S rRNA gene pyrosequencing was investigated in the soil compartments bulk soil, drilosphere, and rhizosphere in topsoil and in the subsoil of an agricultural field. With co-occurrence network analysis, the spatial separation of typically oligotrophs and heterotrophs in subsoil and hotspots was assessed. Four co-occurring bacterial communities were identified and attributed to bulk topsoil, bulk subsoil, drilosphere, and rhizosphere. The bacterial phyla Proteobacteria and Bacteroidetes, which represent many copiotrophic bacteria, are affiliated to the hotspot communities – the rhizosphere and drilosphere – both in topsoil and subsoil. Acidobacteria, Actinobacteria, Gemmatimonadetes, Planctomycetes, and Verrucomicrobia with many oligotrophic bacteria, are the abundant groups of the bulk subsoil community. The bacterial core microbiome in this soil was estimated and only covers 7.6% of the bacterial sequencing reads but includes both oligotrophic and copiotrophic bacteria. Instead, the archaeal core microbiome includes 56% of the overall archaeal diversity and comprises only the ammonium oxidizing Nitrososphaera. Thus, the spatial variability of nutrient quality and quantity strongly shapes the bacterial community composition and their interaction in subsoil, whereas archaea are a stable backbone of the soil prokaryotes.

El Fenómeno de Consumo y el Consumo en Marketing

Directory of Open Access Journals (Sweden)

Dagoberto Páramo Morales

2004-01-01

Full Text Available En este artículo se presentan las principales características que tipifican el fenómeno de consumo en las sociedades contemporáneas. Para lograrlo, primero se revisan algunas aproximaciones conceptuales del consumo, visto como fenómeno social, asociándolo con el simbolismo de consumo, los rituales, las posesiones y el materialismo como motores propulsores de la concepción y práctica del marketing de hoy.

The annual carbon budget for fen and forest in a wetland at Arctic treeline

Energy Technology Data Exchange (ETDEWEB)

Rouse, W. R. [McMaster Univ., School of Geography and Geology, Hamilton, ON (Canada); Bello, R. L.; D' Souza, A. [York Univ., Dept. of Geography, Toronto, ON (Canada); Griffis, T. J. [Minnesota Univ., Dept. of Soil, Water and Climate, St. Paul, MN (United States); LaFleur, P. M. [Trent Univ., Dept. of Geography, Peterborough, ON (Canada)

2002-09-01

This study of a wetland system at the Arctic treeline compares two carbon budget estimates, one derived from long-term growth rates of organic soil and the other based on shorter-term flux measurements. Result showed that while there was a small loss of carbon from the ecosystem in the case of tundra fen over a period of fifty-three years, the adjacent open subarctic forest showed large gains in atmospheric carbon dioxide during the same period. These longer-term data were supported by shorter-term flux measurements, which also showed carbon loss by the fen and carbon uptake by the forest. The shorter term data indicate that the carbon loss from the fen during this period was attributable to one particularly dry year. The different rates of carbon exchange appear to be controlled by two primary factors. The first is the enhanced development in the fen of a photosynthesis-inhibiting hummock-hollow landscape, while the second is related to warmer and drier average growing season conditions, which inhibit carbon dioxide uptake in the fen and enhances it in the forest. 24 refs., 4 tabs., 3 figs.

Missed cleavage opportunities by FEN1 lead to Okazaki fragment maturation via the long-flap pathway

KAUST Repository

Zaher, Manal S.; Rashid, Fahad; Song, Bo; Joudeh, Luay I; Sobhy, Mohamed Abdelmaboud; Tehseen, Muhammad; Hingorani, Manju M; Hamdan, Samir

2018-01-01

RNA-DNA hybrid primers synthesized by low fidelity DNA polymerase α to initiate eukaryotic lagging strand synthesis must be removed efficiently during Okazaki fragment (OF) maturation to complete DNA replication. In this process, each OF primer is displaced and the resulting 5'-single-stranded flap is cleaved by structure-specific 5'-nucleases, mainly Flap Endonuclease 1 (FEN1), to generate a ligatable nick. At least two models have been proposed to describe primer removal, namely short- and long-flap pathways that involve FEN1 or FEN1 along with Replication Protein A (RPA) and Dna2 helicase/nuclease, respectively. We addressed the question of pathway choice by studying the kinetic mechanism of FEN1 action on short- and long-flap DNA substrates. Using single molecule FRET and rapid quench-flow bulk cleavage assays, we showed that unlike short-flap substrates, which are bound, bent and cleaved within the first encounter between FEN1 and DNA, long-flap substrates can escape cleavage even after DNA binding and bending. Notably, FEN1 can access both substrates in the presence of RPA, but bending and cleavage of long-flap DNA is specifically inhibited. We propose that FEN1 attempts to process both short and long flaps, but occasional missed cleavage of the latter allows RPA binding and triggers the long-flap OF maturation pathway.

Missed cleavage opportunities by FEN1 lead to Okazaki fragment maturation via the long-flap pathway

KAUST Repository

Zaher, Manal S.

2018-01-27

RNA-DNA hybrid primers synthesized by low fidelity DNA polymerase α to initiate eukaryotic lagging strand synthesis must be removed efficiently during Okazaki fragment (OF) maturation to complete DNA replication. In this process, each OF primer is displaced and the resulting 5\\'-single-stranded flap is cleaved by structure-specific 5\\'-nucleases, mainly Flap Endonuclease 1 (FEN1), to generate a ligatable nick. At least two models have been proposed to describe primer removal, namely short- and long-flap pathways that involve FEN1 or FEN1 along with Replication Protein A (RPA) and Dna2 helicase/nuclease, respectively. We addressed the question of pathway choice by studying the kinetic mechanism of FEN1 action on short- and long-flap DNA substrates. Using single molecule FRET and rapid quench-flow bulk cleavage assays, we showed that unlike short-flap substrates, which are bound, bent and cleaved within the first encounter between FEN1 and DNA, long-flap substrates can escape cleavage even after DNA binding and bending. Notably, FEN1 can access both substrates in the presence of RPA, but bending and cleavage of long-flap DNA is specifically inhibited. We propose that FEN1 attempts to process both short and long flaps, but occasional missed cleavage of the latter allows RPA binding and triggers the long-flap OF maturation pathway.

Seagrass as major source of transparent exopolymer particles in the oligotrophic Mediterranean coast

KAUST Repository

Iuculano, Francesca

2017-01-09

The role of seagrass, Posidonia oceanica, meadows as a source of transparent exopolymer particles (TEP) to Mediterranean coastal waters was tested by comparing the TEP dynamics in two adjacent coastal waters in the oligotrophic NW Mediterranean Sea, one characterized by oligotrophic open-sea waters and the other accumulating seagrass leaf litter, together with an experimental examination of TEP release by seagrass litter. TEP concentrations ranged from 4.6 µg XG Eq L−1 to 90.6 µg XG Eq L−1, with mean (±SE) values of 38.7 (±2.02) µg XG Eq L−1 in the site devoid of seagrass litter, whereas the coastal beach site accumulating leaf litter had > 10-fold mean TEP concentrations of 487.02 (±72.8) µg XG Eq L−1 . Experimental evaluation confirmed high rates of TEP production by P. oceanica litter, allowing calculations of the associated TEP yield. We demonstrated that P. oceanica is an important source of TEP to the Mediterranean Sea, contributing an estimated 0.10 Tg C as TEP annually. TEP release by P. oceanica seagrass explains the elevated TEP concentration relative to the low chlorophyll a concentration in the Mediterranean Sea.

Sea surface temperature control of taxon specific phytoplankton production along an oligotrophic gradient in the Mediterranean Sea

NARCIS (Netherlands)

van de Poll, W.H.V.; Boute, P.G.; Rozema, P.D.; Buma, A.; Kulk, G.; Rijkenberg, M.J.

2015-01-01

The current study aimed to assess changes in phytoplankton composition and productivity along an oligotrophic gradient in relation to changes in sea surface temperature (SST). Phytoplankton pigments, nutrients, and physical water column properties were studied along a longitudinal transect in the

Comparative studies of the nitrogen metabolism of phytoplankton and periphyton in oligotrophic lakes

International Nuclear Information System (INIS)

Axler, R.P.; Goldman, C.R.; Reuter, J.E.; Loeb, S.L.; Priscu, J.C.; Carlton, R.G.

1983-01-01

This report presents the preliminary data of limnological research at the meso-oligotrophic Castle Lake, CA and at the ultratrophic Lake Tahoe, CA-NEV, USA, during 1980 to 1981. The areas of study were effects of nutrients enrichment and deficiency on primary producers; nitrogen cycling and nitrogen metabolism of benthic and planktonic algae and whole-epilimnion enrichment with ammonium nitrate. Tracer techniques using 14 C- and 15 N-labelled compounds were employed in the study

Determination of the 54Fe(n, 2n)53gFe and 54Fe(n, 2n)53mFe cross sections averaged over a 235U fission neutron spectrum

International Nuclear Information System (INIS)

Ribeiro Guevara, S.; Arribere, M.; Kestelman, A.J.

2002-01-01

The reaction cross sections averaged over a 235 U fission neutron spectrum have been measured for the 54 Fe(n, 2n) 53g Fe and 54 Fe(n, 2n) 53m Fe threshold reactions. The values found are, respectively: (1.14 ± 0.13) μb, and (0.52 ± 0.16) μb. The measured cross sections are referred to the (111± 3) mb standard cross section of the 58 Ni(n, p) 58m+g Co reaction. The (81.7 ± 2.2) mb standard cross section value for the 54 Fe(n, p) 54 Mn reaction, was also used as a monitor to check the results obtained with the Ni standard, leading to an excellent agreement. (author)

Microbial activity and community structure in two drained fen soils in the Ljubljana Marsh

NARCIS (Netherlands)

Kraigher, Barbara; Stres, Blaz; Hacin, Janez; Ausec, Luka; Mahne, Ivan; van Elsas, Jan D.; Mandic-Mulec, Ines

Fen peatlands are specific wetland ecosystems containing high soil organic carbon (SOC). There is a general lack of knowledge about the microbial communities that abound in these systems. We examined the microbial activity and community structure in two fen soils differing in SOC content sampled

Phosphorus cycling and partitioning in an oligotrophic Everglades wetland ecosystem: A radioisotope tracing study

Science.gov (United States)

Noe, G.B.; Scinto, L.J.; Taylor, J.; Childers, D.L.; Jones, R.D.

2003-01-01

1. Our goal was to quantify short-term phosphorus (P) partitioning and identify the ecosystem components important to P cycling in wetland ecosystems. To do this, we added P radiotracer to oligotrophic, P-limited Everglades marshes. 32PO4 was added to the water column in six 1-m2 enclosed mesocosms located in long-hydroperiod marshes of Shark River Slough, Everglades National Park. Ecosystem components were then repeatedly sampled over 18 days. 2. Water column particulates (>0.45 ??m) incorporated radiotracer within the first minute after dosing and stored 95-99% of total water column 32P activity throughout the study. Soluble (<0.45 ??m) 32P in the water column, in contrast, was always <5% of the 32P in surface water. Periphyton, both floating and attached to emergent macrophytes, had the highest specific activity of 32P (Bq g-131P) among the different ecosystem components. Fish and aquatic macroinvertebrates also had high affinity for P, whereas emergent macrophytes, soil and flocculent detrital organic matter (floc) had the lowest specific activities of radiotracer. 3. Within the calcareous, floating periphyton mats, 81% of the initial 32P uptake was associated with Ca, but most of this 32P entered and remained within the organic pool (Ca-associated = 14% of total) after 1 day. In the floc layer, 32P rapidly entered the microbial pool and the labile fraction was negligible for most of the study. 4. Budgeting of the radiotracer indicated that 32P moved from particulates in the water column to periphyton and floc and then to the floc and soil over the course of the 18 days incubations. Floc (35% of total) and soil (27%) dominated 32P storage after 18 days, with floating periphyton (12%) and surface water (10%) holding smaller proportions of total ecosystem 32P. 5. To summarise, oligotrophic Everglades marshes exhibited rapid uptake and retention of labile 32P. Components dominated by microbes appear to control short-term P cycling in this oligotrophic ecosystem.

High bacterial diversity in epilithic biofilms of oligotrophic mountain lakes.

Science.gov (United States)

Bartrons, Mireia; Catalan, Jordi; Casamayor, Emilio O

2012-11-01

Benthic microbial biofilms attached to rocks (epilithic) are major sites of carbon cycling and can dominate ecosystem primary production in oligotrophic lakes. We studied the bacterial community composition of littoral epilithic biofilms in five connected oligotrophic high mountain lakes located at different altitudes by genetic fingerprinting and clone libraries of the 16S rRNA gene. Different intra-lake samples were analyzed, and consistent changes in community structure (chlorophyll a and organic matter contents, and bacterial community composition) were observed along the altitudinal gradient, particularly related with the location of the lake above or below the treeline. Epilithic biofilm genetic fingerprints were both more diverse among lakes than within lakes and significantly different between montane (below the tree line) and alpine lakes (above the tree line). The genetic richness in the epilithic biofilm was much higher than in the plankton of the same lacustrine area studied in previous works, with significantly idiosyncratic phylogenetic composition (specifically distinct from lake plankton or mountain soils). Data suggest the coexistence of aerobic, anaerobic, phototrophic, and chemotrophic microorganisms in the biofilm, Bacteroidetes and Cyanobacteria being the most important bacterial taxa, followed by Alpha-, Beta-, Gamma-, and Deltaproteobacteria, Chlorobi, Planctomycetes, and Verrucomicrobia. The degree of novelty was especially high for epilithic Bacteroidetes, and up to 50 % of the sequences formed monophyletic clusters distantly related to any previously reported sequence. More than 35 % of the total sequences matched at <95 % identity to any previously reported 16S rRNA gene, indicating that alpine epilithic biofilms are unexplored habitats that contain a substantial degree of novelty within a short geographical distance. Further research is needed to determine whether these communities are involved in more biogeochemical pathways than

Deep silicon maxima in the stratified oligotrophic Mediterranean Sea

Directory of Open Access Journals (Sweden)

Y. Crombet

2011-02-01

Full Text Available The silicon biogeochemical cycle has been studied in the Mediterranean Sea during late summer/early autumn 1999 and summer 2008. The distribution of nutrients, particulate carbon and silicon, fucoxanthin (Fuco, and total chlorophyll-a (TChl-a were investigated along an eastward gradient of oligotrophy during two cruises (PROSOPE and BOUM encompassing the entire Mediterranean Sea during the stratified period. At both seasons, surface waters were depleted in nutrients and the nutriclines gradually deepened towards the East, the phosphacline being the deepest in the easternmost Levantine basin. Following the nutriclines, parallel deep maxima of biogenic silica (DSM, fucoxanthin (DFM and TChl-a (DCM were evidenced during both seasons with maximal concentrations of 0.45 μmol L⁻¹ for BSi, 0.26 μg L⁻¹ for Fuco, and 1.70 μg L⁻¹ for TChl-a, all measured during summer. Contrary to the DCM which was a persistent feature in the Mediterranean Sea, the DSM and DFMs were observed in discrete areas of the Alboran Sea, the Algero-Provencal basin, the Ionian sea and the Levantine basin, indicating that diatoms were able to grow at depth and dominate the DCM under specific conditions. Diatom assemblages were dominated by Chaetoceros spp., Leptocylindrus spp., Pseudonitzschia spp. and the association between large centric diatoms (Hemiaulus hauckii and Rhizosolenia styliformis and the cyanobacterium Richelia intracellularis was observed at nearly all sites. The diatom's ability to grow at depth is commonly observed in other oligotrophic regions and could play a major role in ecosystem productivity and carbon export to depth. Contrary to the common view that Si and siliceous phytoplankton are not major components of the Mediterranean biogeochemistry, we suggest here that diatoms, by persisting at depth during the stratified period, could contribute to a

Suspended marine particulate proteins in coastal and oligotrophic waters

Science.gov (United States)

Bridoux, Maxime C.; Neibauer, Jaqui; Ingalls, Anitra E.; Nunn, Brook L.; Keil, Richard G.

2015-03-01

Metaproteomic analyses were performed on suspended sediments collected in one coastal environment (Washington margin, Pacific Ocean, n = 5) and two oligotrophic environments (Atlantic Ocean near BATS, n = 5, and Pacific Ocean near HOTS, n = 5). Using a database of 2.3 million marine proteins developed using the NCBI database, 443 unique peptides were detected from which 363 unique proteins were identified. Samples from the euphotic zone contained on average 2-3x more identifiable proteins than deeper waters (150-1500 m) and these proteins were predominately from photosynthetic organisms. Diatom peptides dominate the spectra of the Washington margin while peptides from cyanobacteria, such as Synechococcus sp. dominated the spectra of both oligotrophic sites. Despite differences in the exact proteins identified at each location, there is good agreement for protein function and cellular location. Proteins in surface waters code for a variety of cellular functions including photosynthesis (24% of detected proteins), energy production (10%), membrane production (9%) and genetic coding and reading (9%), and are split 60-40 between membrane proteins and intracellular cytoplasmic proteins. Sargasso Sea surface waters contain a suite of peptides consistent with proteins involved in circadian rhythms that promote both C and N fixation at night. At depth in the Sargasso Sea, both muscle-derived myosin protein and the muscle-hydrolyzing proteases deseasin MCP-01 and metalloprotease Mcp02 from γ-proteobacteria were observed. Deeper waters contain peptides predominately sourced from γ-proteobacteria (37% of detected proteins) and α-proteobacteria (26%), although peptides from membrane and photosynthetic proteins attributable to phytoplankton were still observed (13%). Relative to surface values, detection frequencies for bacterial membrane proteins and extracellular enzymes rose from 9 to 16 and 2 to 4% respectively below the thermocline and the overall balance between

From groundwater abstraction to vegetative response in fen ecosystems

DEFF Research Database (Denmark)

Johansen, Ole Munch; Jensen, Jacob Birk; Pedersen, Morten Lauge

2014-01-01

Hydrological effects of groundwater abstraction near a Danish river valley have been assessed by integrated hydrological modelling. The study site contains groundwater-dependent terrestrial ecosystems in terms of fen and spring habitats that are highly dependent on regional and local scale...... hydrology. Fens are rare and threatened worldwide due to pressures from agriculture, to lack of appropriate management and to altered catchment hydrology. A solid foundation for hydrological modelling was established based on intensive monitoring at the site, combined with full-scale pumping tests...... in the area. A regional groundwater model was used to describe the dynamics in groundwater recharge and the large-scale discharge to streams. A local grid refinement approach was then applied in a detailed assessment of damage in order to balance the computational effort and the need for a high spatial...

Small molecule inhibitors uncover synthetic genetic interactions of human flap endonuclease 1 (FEN1 with DNA damage response genes.

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Thomas A Ward

Full Text Available Flap endonuclease 1 (FEN1 is a structure selective endonuclease required for proficient DNA replication and the repair of DNA damage. Cellularly active inhibitors of this enzyme have previously been shown to induce a DNA damage response and, ultimately, cell death. High-throughput screens of human cancer cell-lines identify colorectal and gastric cell-lines with microsatellite instability (MSI as enriched for cellular sensitivity to N-hydroxyurea series inhibitors of FEN1, but not the PARP inhibitor olaparib or other inhibitors of the DNA damage response. This sensitivity is due to a synthetic lethal interaction between FEN1 and MRE11A, which is often mutated in MSI cancers through instabilities at a poly(T microsatellite repeat. Disruption of ATM is similarly synthetic lethal with FEN1 inhibition, suggesting that disruption of FEN1 function leads to the accumulation of DNA double-strand breaks. These are likely a result of the accumulation of aberrant replication forks, that accumulate as a consequence of a failure in Okazaki fragment maturation, as inhibition of FEN1 is toxic in cells disrupted for the Fanconi anemia pathway and post-replication repair. Furthermore, RAD51 foci accumulate as a consequence of FEN1 inhibition and the toxicity of FEN1 inhibitors increases in cells disrupted for the homologous recombination pathway, suggesting a role for homologous recombination in the resolution of damage induced by FEN1 inhibition. Finally, FEN1 appears to be required for the repair of damage induced by olaparib and cisplatin within the Fanconi anemia pathway, and may play a role in the repair of damage associated with its own disruption.

Phytoplankton biovolume is independent from the slope of the size spectrum in the oligotrophic atlantic ocean

KAUST Repository

Moreno-Ostos, Enrique

2015-08-06

Modelling the size-abundance spectrum of phytoplankton has proven to be a very useful tool for the analysis of physical-biological coupling and the vertical flux of carbon in oceanic ecosystems at different scales. A frequent observation relates high phytoplankton biovolume in productive regions with flatter spectrum slope and the opposite in oligotrophic ecosystems. Rather than this, the relationship between high biovolume phytoplankton assemblages and flatter size-abundance spectra does not correspond with measurements of the phytoplankton community in the Atlantic Ocean open waters. As part of the Malaspina Circunnavegation Expedition, sixty seven sampling stations within the Atlantic Ocean covering six oceanographic provinces, at different seasons, produced a complete set of phytoplankton size-spectra whose slope and biovolume did not show any obvious interrelation. In these oligotrophic sites, small (procaryotes) and medium-size (nanoplankton) cells are responsible for the most part of biovolume, and their response to environmental conditions does not apply to changes in the size-abundance spectrum slope as expected in richer, large-cell dominated ecosystems.

Decomposition rate of peat-forming plants in the oligotrophic peatland at the first stages of destruction

Science.gov (United States)

Nikonova, L. G.; Golovatskaya, E. A.; Terechshenko, N. N.

2018-03-01

The research presents quantitative estimates of the decomposition rate of plant residues at the initial stages of the decay of two plant species (Eriophorum vaginatum and Sphagnum fuscum) in a peat deposit of the oligotrophic bog in the southern taiga subzone of Western Siberia. We also studied a change in the content of total carbon and nitrogen in plant residues and the activity of microflora in the initial stages of decomposition. At the initial stage of the transformation process of peat-forming plants the losses of mass of Sph. fuscum is 2.5 times lower then E. vaginatum. The most active mass losses, as well as a decrease in the total carbon content, is observed after four months of the experiment. The most active carbon removal is characteristic for E. vaginatum. During the decomposition of plant residues, the nitrogen content decreases, and the most intense nitrogen losses were characteristic for Sph. fuscum. The microorganisms assimilating organic and mineral nitrogen are more active in August, the oligotrophic and cellulolytic microorganisms – in July.

Literatura expandida: el fenómeno fanfiction en español

OpenAIRE

Sanz Martínez, Sandra

2017-01-01

En este trabajo se pretende abordar el estudio del llamado “fenómeno fanfiction”, un fenómeno que ha sacudido internet en las últimas décadas y que supone una nueva forma de creación de literatura. La creación de fanfiction supone la realización de una obra, normalmente narrativa, cuyo contenido contiene aspectos de una obra de ficción publicada, siempre sin ánimo de lucro. Departamento de Literatura Española y Teoría de la Literatura y Literatura Comparada Grado en Español: Lengua y...

Microbial ecology in a future climate: effects of temperature and moisture on microbial communities of two boreal fens.

Science.gov (United States)

Peltoniemi, Krista; Laiho, Raija; Juottonen, Heli; Kiikkilä, Oili; Mäkiranta, Päivi; Minkkinen, Kari; Pennanen, Taina; Penttilä, Timo; Sarjala, Tytti; Tuittila, Eeva-Stiina; Tuomivirta, Tero; Fritze, Hannu

2015-07-01

Impacts of warming with open-top chambers on microbial communities in wet conditions and in conditions resulting from moderate water-level drawdown (WLD) were studied across 0-50 cm depth in northern and southern boreal sedge fens. Warming alone decreased microbial biomass especially in the northern fen. Impact of warming on microbial PLFA and fungal ITS composition was more obvious in the northern fen and linked to moisture regime and sample depth. Fungal-specific PLFA increased in the surface peat in the drier regime and decreased in layers below 10 cm in the wet regime after warming. OTUs representing Tomentella and Lactarius were observed in drier regime and Mortierella in wet regime after warming in the northern fen. The ectomycorrhizal fungi responded only to WLD. Interestingly, warming together with WLD decreased archaeal 16S rRNA copy numbers in general, and fungal ITS copy numbers in the northern fen. Expectedly, many results indicated that microbial response on warming may be linked to the moisture regime. Results indicated that microbial community in the northern fen representing Arctic soils would be more sensitive to environmental changes. The response to future climate change clearly may vary even within a habitat type, exemplified here by boreal sedge fen. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Formation dynamics of FeN thin films on Cu(100)

KAUST Repository

Heryadi, Dodi

2012-01-01

To investigate the structural and magnetic properties of thin films of FeN we have performed ab initio molecular dynamics simulations of their formation on Cu(100) substrates. The iron nitride layers exhibit a p4gm(2 × 2) reconstruction and order ferromagnetically in agreement with experiment. We establish the dynamics and time scale of the film formation as a function of the film thickness. The process is split in two phases: formation of almost flat FeN layers and optimization of the distance to the substrate. Our calculated magnetic moments are 1.67 μ B, 2.14 μ B, and 2.21 μ B for one, two, and three monolayers of iron nitride. © 2011 Elsevier B.V. All rights reserved.

High diversity and suggested endemicity of culturable Actinobacteria in an extremely oligotrophic desert oasis

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Hector Fernando Arocha-Garza

2017-05-01

Full Text Available The phylum Actinobacteria constitutes one of the largest and anciently divergent phyla within the Bacteria domain. Actinobacterial diversity has been thoroughly researched in various environments due to its unique biotechnological potential. Such studies have focused mostly on soil communities, but more recently marine and extreme environments have also been explored, finding rare taxa and demonstrating dispersal limitation and biogeographic patterns for Streptomyces. To test the distribution of Actinobacteria populations on a small scale, we chose the extremely oligotrophic and biodiverse Cuatro Cienegas Basin (CCB, an endangered oasis in the Chihuahuan desert to assess the diversity and uniqueness of Actinobacteria in the Churince System with a culture-dependent approach over a period of three years, using nine selective media. The 16S rDNA of putative Actinobacteria were sequenced using both bacteria universal and phylum-specific primer pairs. Phylogenetic reconstructions were performed to analyze OTUs clustering and taxonomic identification of the isolates in an evolutionary context, using validated type species of Streptomyces from previously phylogenies as a reference. Rarefaction analysis for total Actinobacteria and for Streptomyces isolates were performed to estimate species’ richness in the intermediate lagoon (IL in the oligotrophic Churince system. A total of 350 morphologically and nutritionally diverse isolates were successfully cultured and characterized as members of the Phylum Actinobacteria. A total of 105 from the total isolates were successfully subcultured, processed for DNA extraction and 16S-rDNA sequenced. All strains belong to the order Actinomycetales, encompassing 11 genera of Actinobacteria; the genus Streptomyces was found to be the most abundant taxa in all the media tested throughout the 3-year sampling period. Phylogenetic analysis of our isolates and another 667 reference strains of the family Streptomycetaceae

High diversity and suggested endemicity of culturable Actinobacteria in an extremely oligotrophic desert oasis

Science.gov (United States)

Arocha-Garza, Hector Fernando; Canales-Del Castillo, Ricardo; Eguiarte, Luis E.; Souza, Valeria

2017-01-01

The phylum Actinobacteria constitutes one of the largest and anciently divergent phyla within the Bacteria domain. Actinobacterial diversity has been thoroughly researched in various environments due to its unique biotechnological potential. Such studies have focused mostly on soil communities, but more recently marine and extreme environments have also been explored, finding rare taxa and demonstrating dispersal limitation and biogeographic patterns for Streptomyces. To test the distribution of Actinobacteria populations on a small scale, we chose the extremely oligotrophic and biodiverse Cuatro Cienegas Basin (CCB), an endangered oasis in the Chihuahuan desert to assess the diversity and uniqueness of Actinobacteria in the Churince System with a culture-dependent approach over a period of three years, using nine selective media. The 16S rDNA of putative Actinobacteria were sequenced using both bacteria universal and phylum-specific primer pairs. Phylogenetic reconstructions were performed to analyze OTUs clustering and taxonomic identification of the isolates in an evolutionary context, using validated type species of Streptomyces from previously phylogenies as a reference. Rarefaction analysis for total Actinobacteria and for Streptomyces isolates were performed to estimate species’ richness in the intermediate lagoon (IL) in the oligotrophic Churince system. A total of 350 morphologically and nutritionally diverse isolates were successfully cultured and characterized as members of the Phylum Actinobacteria. A total of 105 from the total isolates were successfully subcultured, processed for DNA extraction and 16S-rDNA sequenced. All strains belong to the order Actinomycetales, encompassing 11 genera of Actinobacteria; the genus Streptomyces was found to be the most abundant taxa in all the media tested throughout the 3-year sampling period. Phylogenetic analysis of our isolates and another 667 reference strains of the family Streptomycetaceae shows that our

Rate-determining Step of Flap Endonuclease 1 (FEN1) Reflects a Kinetic Bias against Long Flaps and Trinucleotide Repeat Sequences.

Science.gov (United States)

Tarantino, Mary E; Bilotti, Katharina; Huang, Ji; Delaney, Sarah

2015-08-21

Flap endonuclease 1 (FEN1) is a structure-specific nuclease responsible for removing 5'-flaps formed during Okazaki fragment maturation and long patch base excision repair. In this work, we use rapid quench flow techniques to examine the rates of 5'-flap removal on DNA substrates of varying length and sequence. Of particular interest are flaps containing trinucleotide repeats (TNR), which have been proposed to affect FEN1 activity and cause genetic instability. We report that FEN1 processes substrates containing flaps of 30 nucleotides or fewer at comparable single-turnover rates. However, for flaps longer than 30 nucleotides, FEN1 kinetically discriminates substrates based on flap length and flap sequence. In particular, FEN1 removes flaps containing TNR sequences at a rate slower than mixed sequence flaps of the same length. Furthermore, multiple-turnover kinetic analysis reveals that the rate-determining step of FEN1 switches as a function of flap length from product release to chemistry (or a step prior to chemistry). These results provide a kinetic perspective on the role of FEN1 in DNA replication and repair and contribute to our understanding of FEN1 in mediating genetic instability of TNR sequences. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

E-sports: um fenómeno da cultura digital contemporânea

OpenAIRE

Saraiva, Pedro André Cardoso

2013-01-01

Mestrado em Comunicação, Cultura e Tecnologias de Informação A competição entre dois jogadores está na génese dos jogos digitais e é esse o fator que está no centro deste trabalho, que explora o fenómeno do desporto eletrónico, os e-sports. Este conceito representa a prática competitiva e profissionalmente organizada nos videojogos. Situado conceptualmente entre o gaming e o desporto, os e-sports apresentam-se como um fenómeno da cultura digital contemporânea, partic...

Primary marine aerosol emissions from the Mediterranean Sea during pre-bloom and oligotrophic conditions: correlations to seawater chlorophyll a from a mesocosm study

Science.gov (United States)

Schwier, A. N.; Rose, C.; Asmi, E.; Ebling, A. M.; Landing, W. M.; Marro, S.; Pedrotti, M.-L.; Sallon, A.; Iuculano, F.; Agusti, S.; Tsiola, A.; Pitta, P.; Louis, J.; Guieu, C.; Gazeau, F.; Sellegri, K.

2015-07-01

The effect of ocean acidification and changing water conditions on primary (and secondary) marine aerosol emissions is not well understood on a regional or a global scale. To investigate this effect as well as the indirect effect on aerosol that changing biogeochemical parameters can have, ~ 52 m3 pelagic mesocosms were deployed for several weeks in the Mediterranean Sea during both winter pre-bloom and summer oligotrophic conditions and were subjected to various levels of CO2 to simulate the conditions foreseen in this region for the coming decades. After seawater sampling, primary bubble-bursting aerosol experiments were performed using a plunging water jet system to test both chemical and physical aerosol parameters (10-400 nm). Comparing results obtained during pre-bloom and oligotrophic conditions, we find the same four log-normal modal diameters (18.5 ± 0.6, 37.5 ± 1.4, 91.5 ± 2.0, 260 ± 3.2 nm) describing the aerosol size distribution during both campaigns, yet pre-bloom conditions significantly increased the number fraction of the second (Aitken) mode, with an amplitude correlated to virus-like particles, heterotrophic prokaryotes, TEPs (transparent exopolymeric particles), chlorophyll a and other pigments. Organic fractions determined from kappa closure calculations for the diameter, Dp ~ 50 nm, were much larger during the pre-bloom period (64 %) than during the oligotrophic period (38 %), and the organic fraction decreased as the particle size increased. Combining data from both campaigns together, strong positive correlations were found between the organic fraction of the aerosol and chlorophyll a concentrations, heterotrophic and autotrophic bacteria abundance, and dissolved organic carbon (DOC) concentrations. As a consequence of the changes in the organic fraction and the size distributions between pre-bloom and oligotrophic periods, we find that the ratio of cloud condensation nuclei (CCN) to condensation nuclei (CN) slightly decreased during the

Compostos fenólicos totais e antocianinas em suco de uva

OpenAIRE

Malacrida,Cassia R.; Motta,Silvana da

2005-01-01

As concentrações de compostos fenólicos totais e antocianinas em sucos de uva reconstituídos e simples, de diferentes marcas, disponíveis no comércio varejista da região metropolitana de Belo Horizonte (Minas Gerais) foram quantificadas. Também se determinou a contribuição das antocianinas poliméricas à cor e o índice de degradação das antocianinas. Os teores de compostos fenólicos totais variaram entre 0,27 e 2,41 g/L e as concentrações de antocianinas de 1,17 a 66,80 mg/L. Foram observadas ...

Fenómenos mixtos en la división neurosis y psicosis: un estudio de las elaboraciones freudianas

OpenAIRE

Aguirre, Javier

2013-01-01

El presente trabajo aborda algunos desarrollos freudianos referidos a la división neurosis y psicosis. El análisis se centra en la hipótesis referida a la existencia de fenómenos mixtos, neuróticos y psicóticos, o sea, fenómenos que se presentarían de una misma manera en su articulación en ambas categorías. Se concluye que la expresión “fenómenos mixtos” no es adecuada, en la medida que Freud aborda el fenómeno siempre de una manera articulada y no de una manera aislada, es decir, la caracter...

Compostos fenólicos e capacidade antioxidante em frutos de tomateiros mutantes fotomorfogenéticos

Directory of Open Access Journals (Sweden)

Tiago Dias

2015-05-01

Full Text Available Compostos fenólicos e capacidade antioxidante são mecanismos de defesa das plantas aos danos do estresse oxidativo. Os compostos fenólicos são sintetizados pela via dos fenilpropanoides, cuja enzima chave, fenilalanina amônia liase, é influenciada pela luz e ação de fotorreceptores, como o fitocromo. O objetivo do presente trabalho é avaliar a concentração de compostos fenólicos e a capacidade antioxidante de frutos de microtomateiro selvagem, cultivar "Micro-Tom" (MT, e seus mutantes fotomorfogenéticos high pigment 1 (hp1, super-responsivo a eventos mediados por luz e aurea (au, deficiente quantitativo em fitocromos. Vinte frutos maduros de cada genótipo (MT, hp1 e au foram utilizados para as análises, realizadas em triplicata. Para quantificação dos compostos fenólicos totais, foi utilizado o método de Folin-Ciocalteu e a capacidade antioxidante foi realizada pelos métodos Ferric Reducing Antioxidant Power (FRAP e 2,2-diphenyl-1-picrylhydrazyl (DPPH. Os frutos do mutante hp1 apresentaram maiores conteúdos de compostos fenólicos totais e também maior capacidade antioxidante em relação à cultivar selvagem ("MT" e ao mutante au, o qual não diferiu significativamente da cultivar "MT".

Una revisión del fenómeno de aislamiento magnético

Directory of Open Access Journals (Sweden)

Zósimo Arévalo Velosa

2007-09-01

Full Text Available Los dispositivos de alta energía son diseñados para que funcionen con campos eléctricos y magnéticos extrema-damente altos. Debido a esto, dichos dispositivos presentan fenómenos y comportamientos no lineales, como el aislamiento magnético que altera el transporte de los electrones. La no linealidad ha obligado a analizar y revisar desde el punto de vista matemático las condiciones de frontera y las soluciones del problema. El objetivo de este trabajo es exponer el tema a un nivel que facilite su difusión entre la comunidad académica no familiarizada con el mismo. Para ello, el trabajo presenta una descripción de los fenómenos que se generan cuando hay campos eléctricos y magnéticos muy altos, tomando el caso de un diodo plano al vacío, así como las ecuaciones que modelan el fenómeno de aislamiento magnético; también demuestra la existencia de las soluciones y encuentra las positivas en base a los métodos de solución superior e inferior para problemas de valor de frontera, y pro-porciona algunos ejemplos de aplicación del fenómeno de aislamiento magnético.

Filtering fens: Mechanisms explaining phosphorus-limited hotspots of biodiversity in wetlands adjacent to heavily fertilized areas

NARCIS (Netherlands)

Cusell, C.; Kooijman, A.; Fernandez, F.; van Wirdum, G.; Geurts, J.J.M.; van Loon, E.E.; Kalbitz, K.; Lamers, L.P.M.

2014-01-01

The conservation of biodiverse wetland vegetation, including that of rich fens, has a high priority at a global scale. Although P-eutrophication may strongly decrease biodiversity in rich fens, some well-developed habitats do still survive in highly fertilized regions due to nutrient filtering

A multiple antibiotic and serum resistant oligotrophic strain, Klebsiella pneumoniae MB45 having novel dfrA30, is sensitive to ZnO QDs

Directory of Open Access Journals (Sweden)

Chakrabarti Pinak

2011-05-01

Full Text Available Abstract Background The aim of this study was to describe a novel trimethoprim resistance gene cassette, designated dfrA30, within a class 1 integron in a facultatively oligotrophic, multiple antibiotic and human serum resistant test strain, MB45, in a population of oligotrophic bacteria isolated from the river Mahananda; and to test the efficiency of surface bound acetate on zinc oxide quantum dots (ZnO QDs as bactericidal agent on MB45. Methods Diluted Luria broth/Agar (10-3 media was used to cultivate the oligotrophic bacteria from water sample. Multiple antibiotic resistant bacteria were selected by employing replica plate method. A rapid assay was performed to determine the sensitivity/resistance of the test strain to human serum. Variable region of class 1 integron was cloned, sequenced and the expression of gene coding for antibiotic resistance was done in Escherichia coli JM 109. Identity of culture was determined by biochemical phenotyping and 16S rRNA gene sequence analyses. A phylogenetic tree was constructed based on representative trimethoprim resistance-mediating DfrA proteins retrieved from GenBank. Growth kinetic studies for the strain MB45 were performed in presence of varied concentrations of ZnO QDs. Results and conclusions The facultatively oligotrophic strain, MB45, resistant to human serum and ten antibiotics trimethoprim, cotrimoxazole, ampicillin, gentamycin, netilmicin, tobramycin, chloramphenicol, cefotaxime, kanamycin and streptomycin, has been identified as a new strain of Klebsiella pneumoniae. A novel dfr gene, designated as dfrA30, found integrated in class 1 integron was responsible for resistance to trimethoprim in Klebsiella pneumoniae strain MB45. The growth of wild strain MB45 was 100% arrested at 500 mg/L concentration of ZnO QDs. To our knowledge this is the first report on application of ZnO quantum dots to kill multiple antibiotics and serum resistant K. pneumoniae strain.

Identification of human flap endonuclease 1 (FEN1) inhibitors using a machine learning based consensus virtual screening.

Science.gov (United States)

Deshmukh, Amit Laxmikant; Chandra, Sharat; Singh, Deependra Kumar; Siddiqi, Mohammad Imran; Banerjee, Dibyendu

2017-07-25

Human Flap endonuclease1 (FEN1) is an enzyme that is indispensable for DNA replication and repair processes and inhibition of its Flap cleavage activity results in increased cellular sensitivity to DNA damaging agents (cisplatin, temozolomide, MMS, etc.), with the potential to improve cancer prognosis. Reports of the high expression levels of FEN1 in several cancer cells support the idea that FEN1 inhibitors may target cancer cells with minimum side effects to normal cells. In this study, we used large publicly available, high-throughput screening data of small molecule compounds targeted against FEN1. Two machine learning algorithms, Support Vector Machine (SVM) and Random Forest (RF), were utilized to generate four classification models from huge PubChem bioassay data containing probable FEN1 inhibitors and non-inhibitors. We also investigated the influence of randomly selected Zinc-database compounds as negative data on the outcome of classification modelling. The results show that the SVM model with inactive compounds was superior to RF with Matthews's correlation coefficient (MCC) of 0.67 for the test set. A Maybridge database containing approximately 53 000 compounds was screened and top ranking 5 compounds were selected for enzyme and cell-based in vitro screening. The compound JFD00950 was identified as a novel FEN1 inhibitor with in vitro inhibition of flap cleavage activity as well as cytotoxic activity against a colon cancer cell line, DLD-1.

Design, construction and performance of an experimental watershed to support a fen peatland for mine landscape reclamation

Science.gov (United States)

Price, J. S.; Petrone, R. M.; Strack, M.; Cooper, D. J.

2017-12-01

In the Alberta oil sands region, fen peatlands comprised 50% of the boreal landscape. Oil sands mining has stripped over 800 km2 of land surface to access bitumen, necessitating landscape reclamation to re-establish functional wetlands. Fens are peat-dominated wetlands that commonly rely on groundwater to supplement their water budget and deliver dissolved solutes that impart a distinct geochemistry, hence vegetation community. A numerical model was used to test the concept and guide selection of earth materials and system geometry. The goal was to maintain the placed peat in a sufficiently wet condition to support wetland plants and become a net carbon sink, in this sub-humid climate. The 32.1 ha Nikanotee Fen Watershed comprises a 7.7 ha upland, that was designed to recharge sufficient water, and deliver it to the 2.9 ha fen via groundwater flow. These features are surrounded by other reclaimed slopes designed to store water, rather than deliver it downslope. Four years of monitoring since construction show the fen maintains a high water table, and the peatland has become a strong carbon sink, even though the hydrological performance of construction materials varied substantially from what was anticipated (lower hydraulic conductivity). However, solutes associated with the tailings sand used in construction are moving towards the fen, and are expected to influence the future vegetation community and system biogeochemistry. One of the biggest uncertainties is the changing performance of soils and vegetation as they develop.

Metódica: Articulación sistema teórico, fenómeno y procesos en el objeto de estudio. Una perspectiva desde el fenómeno pobreza

OpenAIRE

Yajaira Jiménez Zabala

2011-01-01

En este artículo discutimos la visión metódica que toma como apoyo el pivote entre lo cualitativo, lo cuantitativo y el orden de complejidad, en un enfoque plurimetódico, a través del cual se construyó la visión de la pobreza como objeto de estudio. Tal selección, está justificada en tanto se entiende la pobreza como un fenómeno social complejo, por las diversas aristas que le identifican. La combinación de los enfoques metodológicos permitió la aprehensión de los diferentes aspectos del fenó...

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

Science.gov (United States)

Sundareshwar, P. V.; Upadhayay, S.; Abessa, M.; Honomichl, S.; Berdanier, B.; Spaulding, S. A.; Sandvik, C.; Trennepohl, A.

2011-05-01

In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers.

Diversity of picoeukaryotes at an oligotrophic site off the Northeastern Red Sea Coast.

KAUST Repository

Acosta, Francisco

2013-08-20

Picoeukaryotes are protists ≤ 3 μm composed of a wide diversity of taxonomic groups. They are an important constituent of the ocean\\'s microbiota and perform essential ecological roles in marine nutrient and carbon cycles. Despite their importance, the true extent of their diversity has only recently been uncovered by molecular surveys that resulted in the discovery of a substantial number of previously unknown groups. No study on picoeukaryote diversity has been conducted so far in the main Red Sea basin-a unique marine environment characterized by oligotrophic conditions, high levels of irradiance, high salinity and increased water temperature.

High abundances of potentially active ammonia-oxidizing bacteria and archaea in oligotrophic, high-altitude lakes of the Sierra Nevada, California, USA.

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Curtis J Hayden

Full Text Available Nitrification plays a central role in the nitrogen cycle by determining the oxidation state of nitrogen and its subsequent bioavailability and cycling. However, relatively little is known about the underlying ecology of the microbial communities that carry out nitrification in freshwater ecosystems--and particularly within high-altitude oligotrophic lakes, where nitrogen is frequently a limiting nutrient. We quantified ammonia-oxidizing archaea (AOA and bacteria (AOB in 9 high-altitude lakes (2289-3160 m in the Sierra Nevada, California, USA, in relation to spatial and biogeochemical data. Based on their ammonia monooxygenase (amoA genes, AOB and AOA were frequently detected. AOB were present in 88% of samples and were more abundant than AOA in all samples. Both groups showed >100 fold variation in abundance between different lakes, and were also variable through time within individual lakes. Nutrient concentrations (ammonium, nitrite, nitrate, and phosphate were generally low but also varied across and within lakes, suggestive of active internal nutrient cycling; AOB abundance was significantly correlated with phosphate (r(2 = 0.32, p<0.1, whereas AOA abundance was inversely correlated with lake elevation (r(2 = 0.43, p<0.05. We also measured low rates of ammonia oxidation--indicating that AOB, AOA, or both, may be biogeochemically active in these oligotrophic ecosystems. Our data indicate that dynamic populations of AOB and AOA are found in oligotrophic, high-altitude, freshwater lakes.

NO3 uptake in shallow, oligotrophic, mountain lakes: The influence of elevated NO3 concentrations

Science.gov (United States)

Nydick, K.R.; LaFrancois, B.M.; Baron, Jill S.

2004-01-01

Nutrient enrichment experiments were conducted in 1.2-m deep enclosures in 2 shallow, oligotrophic, mountain lakes. 15N-NO3 isotope tracer was used to compare the importance of phytoplankton and benthic compartments (epilithon, surface sediment [epipelon], and subsurface sediment) for NO3 uptake under high and low NO3 conditions. NO3 uptake approached saturation in the high-N lake, but not in the low-N lake. The capacity of phytoplankton and benthic compartments to take up NO3 differed among treatments and between lakes, and depended on water-column nutrient conditions and the history of NO3 availability. Phytoplankton productivity responded strongly to addition of limiting nutrients, and NO3 uptake was related to phytoplankton biomass and photosynthesis. However, more NO3 usually was taken up by benthic compartments (57–92% combined) than by phytoplankton, even though the response of benthic algal biomass to nutrient additions was less pronounced than that of phytoplankton and benthic NO3 uptake was unrelated to benthic algal biomass. In the low-N lake where NO3 uptake was unsaturated, C content or % was related to NO3 uptake in benthic substrates, suggesting that heterotrophic bacterial processes could be important in benthic NO3 uptake. These results suggest that phytoplankton are most sensitive to nutrient additions, but benthic processes are important for NO3 uptake in shallow, oligotrophic lakes.

Phosphorus flux due to Atlantic salmon (Salmo salar) in an oligotrophic upland stream: effects of management and demography

Science.gov (United States)

Keith H. Nislow; John D. Armstrong; Simon. McKelvey

2004-01-01

Little is known concerning the role of Atlantic salmon (Salmo salar) in the transport of nutrients to and from river systems. We used demographic data from the River Bran, an oligotrophic river in Scotland, UK, to construct a budget for the transport of phosphorus (P) and applied it to investigate the effects of management strategies and demographic...

The GAN Exonuclease or the Flap Endonuclease Fen1 and RNase HII Are Necessary for Viability of Thermococcus kodakarensis.

Science.gov (United States)

Burkhart, Brett W; Cubonova, Lubomira; Heider, Margaret R; Kelman, Zvi; Reeve, John N; Santangelo, Thomas J

2017-07-01

Many aspects of and factors required for DNA replication are conserved across all three domains of life, but there are some significant differences surrounding lagging-strand synthesis. In Archaea , a 5'-to-3' exonuclease, related to both bacterial RecJ and eukaryotic Cdc45, that associates with the replisome specifically through interactions with GINS was identified and designated GAN (for G INS- a ssociated n uclease). Despite the presence of a well-characterized flap endonuclease (Fen1), it was hypothesized that GAN might participate in primer removal during Okazaki fragment maturation, and as a Cdc45 homologue, GAN might also be a structural component of an archaeal CMG (Cdc45, MCM, and GINS) replication complex. We demonstrate here that, individually, either Fen1 or GAN can be deleted, with no discernible effects on viability and growth. However, deletion of both Fen1 and GAN was not possible, consistent with both enzymes catalyzing the same step in primer removal from Okazaki fragments in vivo RNase HII has also been proposed to participate in primer processing during Okazaki fragment maturation. Strains with both Fen1 and RNase HII deleted grew well. GAN activity is therefore sufficient for viability in the absence of both RNase HII and Fen1, but it was not possible to construct a strain with both RNase HII and GAN deleted. Fen1 alone is therefore insufficient for viability in the absence of both RNase HII and GAN. The ability to delete GAN demonstrates that GAN is not required for the activation or stability of the archaeal MCM replicative helicase. IMPORTANCE The mechanisms used to remove primer sequences from Okazaki fragments during lagging-strand DNA replication differ in the biological domains. Bacteria use the exonuclease activity of DNA polymerase I, whereas eukaryotes and archaea encode a flap endonuclease (Fen1) that cleaves displaced primer sequences. RNase HII and the GINS-associated exonuclease GAN have also been hypothesized to assist in primer

Formation dynamics of FeN thin films on Cu(100)

KAUST Repository

Heryadi, Dodi; Schwingenschlö gl, Udo

2012-01-01

To investigate the structural and magnetic properties of thin films of FeN we have performed ab initio molecular dynamics simulations of their formation on Cu(100) substrates. The iron nitride layers exhibit a p4gm(2 × 2) reconstruction and order

Impact of water-level changes to aquatic vegetation in small oligotrophic lakes

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Egert VANDEL

2016-06-01

Full Text Available This study demonstrates the effect of drastic water-level changes to the aquatic vegetation in three small oligotrophic lakes situated in Kurtna Kame Field in north-eastern Estonia. The area holds around 40 lakes in 30 km2 of which 18 lakes are under protection as Natura Habitat lakes (Natura 2000 network. The area is under a strong human impact as it is surrounded by oil shale mines, sand quarry, peat harvesting field etc. The most severe impact comes from the groundwater intake established in 1972 in the vicinity of three studied lakes. The exploitation of groundwater led to drastic water-level drops. In 1980s the water-level drops were measured to be up to 3 to 4 meters compared to the levels of 1946. Lake Martiska and Lake Kuradijärv were severely affected and only 29% and 45% of lake area respectively and 21% of initial volume remained. Both lakes were described as oligotrophic lakes before severe human impact and held characteristic macrophytes such as Isoëtes lacustris L., Sparganium angustifolium Michx and Lobelia dortmanna L. As the water level declined the lakes lost their rare characteristic species and can now be described more as a meso- or even eutrophic lakes. When the volume of groundwater abstraction decreased in the 1990s the water levels started to recover but did not reach the natural levels of pre-industrialized era. Also the vegetation did not show any signs of recovery. In 2012 the pumping rates increased again causing a new rapid decline in water levels which almost exceed the previous minimum levels. The water-level monitoring alongside with the macrophyte monitoring data gives us a good case study on how the long term abrupt water-level changes can affect the aquatic vegetation

Restoring sedges and mosses into frost heaving iron fens, San Juan Mountains, Colorado

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R.A. Chimner

2011-08-01

Full Text Available Rare iron fens in the San Juan Mountains of Colorado are frequently in poor condition due to mining, roads and ditches, which have left much of the fen completely bare of vegetation. Natural revegetation is slow to occur in the bare areas because of severe frost heave in the cold mountain climate. Therefore, experimental revegetation plots were conducted in a factorial design with mulching and no mulching, crossed with moss diaspores, sedge transplants, and moss and sedge combined. Mulching influenced surface soil temperatures by reducing the midday highs and increasing the night-time lows, which decreased the frequency and amount of frost heave. Peat moisture also modified frost heave, with the greatest frost heaving occurring near 75 % peat moisture content (water table 10–20 cm below the surface and the least when soils were either wetter or drier. Moss survival was dependent on mulch, with no moss surviving in plots without mulch. Mulching also increased sedge transplant survival. In summary, mulching significantly increased the success of vegetation restoration efforts for frost heave areas in mountain fens.

Synergistic increase of oxygen reduction favourable Fe-N coordination structures in a ternary hybrid of carbon nanospheres/carbon nanotubes/graphene sheets.

Science.gov (United States)

Zhang, Shiming; Liu, Bin; Chen, Shengli

2013-11-14

A Fe/N co-doped ternary nanocarbon hybrid, with uniform bamboo-like carbon nanotubes (CNTs) in situ grown on/between the single/few-layer graphene sheets interspaced by carbon nanosphere aggregates, was prepared through a one-pot heat treatment of a precursor mixture containing graphene oxide, Vulcan XC-72 carbon nanospheres, nitrogen rich melamine and small amounts of Fe ions. Physical characterization including electron microscopic images, N2 adsorption-desorption isotherms, pore size distribution, XPS, XRD, Mössbauer spectra, and EDX revealed that the 0-D/1-D/2-D ternary hybrid architecture not only offered an optimized morphology for high dispersion of each nanocarbon moiety, while the carbon nanosphere interspaced graphene sheets have provided a platform for efficient reaction between Fe ions and melamine molecules, resulting in uniform nucleation and growth of CNTs and formation of high density Fe-N coordination assemblies that have been believed to be the active centers for the oxygen reduction reaction (ORR) in carbon-based nonprecious metal electrocatalysts. In the absence of graphene oxides or carbon nanospheres, a similar heat treatment was found to result in large amounts of elemental Fe and Fe carbides and entangled CNTs with wide diameter distributions. As a result, the ternary Fe/N-doped nanocarbon hybrid exhibits ORR activity much higher than the Fe-N doped single or binary nanocarbon materials prepared under similar heat treatment conditions, and approaching that of the state-of-the-art carbon-supported platinum catalyst (Pt/C) in acidic media, as well as superior stability and methanol tolerance to Pt/C.

Violencia en la pareja, las caras del fenómeno

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Luz Elena Ocampo Otálvaro

2011-01-01

Full Text Available Este trabajo pretende mostrar las diversas caras o facetas del fenómeno de la violencia en la pareja, el mismo que en la literatura es conocido como violencia conyugal, violencia doméstica, violencia por parte del compañero íntimo, etc. Se identifica como un problema de salud pública, debido a los altos costos que genera y la manera como lesiona la vida cotidiana de quienes lo padecen. Se manifiesta en el seno de las relaciones de pareja, e irradia hacia los diversos ámbitos de interacción de los actores: mujer, varón, niño, niña. Involucra a todo el grupo o los grupos familiares de quienes lo viven, y puede lesionar de forma severa a los mismos. Se revisan aspectos del fenómeno, como el hecho que no sólo se presenta en las relaciones en las que la pareja tenga una unión de hecho, sino también en parejas de novios. No solo afecta a las mujeres o a las niñas; también afecta a los hombres. Tampoco es exclusivo de las parejas heterosexuales; los estudios muestran que entre parejas del mismo sexo también está presente. Se trata entonces de un fenómeno universal, multicausal, multidimensional, de salud y de tipo legal, que genera consecuencias que incluyen desde un problema de autoestima, de ansiedad, de depresión, de estrés hasta la muerte misma.

compuestos fenólicos

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Yolanda González García

2005-01-01

Full Text Available En este trabajo se presenta una revisión bibliográfica que tiene como objetivo identificar y analizar alternativas de aprovechamiento del bagazo de Agave tequilana Weber var. Azul. Se proponen dos líneas de investigación para obtener productos de valor agregado a partir de este residuo: 1utilización como fuente de carbono de bajo costo para la producción de biopolímeros y carbohidrasas, con bacterias celulolíticas del género Microbulbifer, Marinobacterium y Sagittula; 2obtención de compuestos fenólicos a partir de la lignina presente en sus fibras. Se concluye, que el bagazo de agave tequilero es un material viable para ser usado como substrato en procesos fermentativos, por lo que existen grandes oportunidades de investigación para desarrollar procesos de bioconversión técnicamente factible, eficiente y económicamente atractivo

Specific growth rate plays a critical role in hydrogen peroxide resistance of the marine oligotrophic ultramicrobacterium Sphingomonas alaskensis strain RB2256

NARCIS (Netherlands)

Ostrowski, M; Cavicchioli, R; Gottschal, JC; Blaauw, Maarten

The marine oligotrophic ultramicrobacterium Sphingomonas alaskensis RB2256 has a physiology that is distinctly different from that of typical copiotrophic marine bacteria, such as Vibrio angustum S14. This includes a high level of inherent stress resistance and the absence of starvation-induced

Lago Maggiore oligotrophication as seen from the long-term evolution of its phytoplankton taxonomic size structure

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Giuseppe MORABITO

2009-02-01

Full Text Available Due to the rapid and common deterioration of aquatic ecosystems, scientists and environmental protection organizations acutely need means capable of producing quantitative estimates for structural deformations of natural communities. Recently, very common biomass size spectra ignore community taxonomic composition, i.e., one of the most important kinds of biological information. Therefore, another very old, but rare in planktonology, method – the traditional taxonomic size spectrum (TTSS – can be helpful. TTSS, a specific form of size-frequency distribution of taxonomic units, reveals repeating patterns of deep subalpine Lago Maggiore (Italy phytoplankton taxonomic structure. The general TTSS pattern was safeguarded during 22 annual cycles (1984-2005, when many principal environmental characteristics were changed considerably during the lake oligotrophication. At the same time, the fine structure deformations of this pattern helped us divide the total oligotrophication process into several stages characterized by notable changes of TTSS peaks' proportions. These peak-height alterations were caused by pronounced changes in the species list and overall taxonomic diversity of the lake phytoplankton. The average cell volume decline was found. It was significantly correlated with the total phosphorus descending trend. This cell volume decline was produced by the addition of numerous species into the medium-and-small size fractions. Typical patterns of the stable and transitory stages were differentiated, which could be valuable for environmental protection and diagnostic applications. The central peak height difference between the stable and the transitory periods was statistically significant. Oligotrophication process decomposition into several more homogenous groups of years was supported by quantitative estimators produced by hierarchical cluster analysis. The highest level of the similarity measure (Pearson r in pairs of annual TTSS was

Comparisons of soil nitrogen mass balances for an ombrotrophic bog and a minerotrophic fen in northern Minnesota

Science.gov (United States)

Brian H. Hill; Terri M. Jicha; LaRae L.P. Lehto; Colleen M. Elonen; Stephen D. Sebestyen; Randy Kolka

2016-01-01

Wecompared nitrogen (N) storage and flux in soils froman ombrotrophic bogwith that of a minerotrophic fen to quantify the differences in N cycling between these two peatlands types in northernMinnesota (USA). Precipitation, atmospheric deposition, and bog and fen outflowswere analyzed for nitrogen species. Upland and peatland soil sampleswere analyzed for N content,...

Fenóis totais, flavonoides totais e atividade antioxidante de Selaginella convoluta (Arn. Spring (Selaginellaceae

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Pedro Guilherme Sousa de Sá

2012-12-01

Full Text Available Selaginella convoluta é uma espécie conhecida no Nordeste do Brasil como “jericó”, e bastante utilizada na medicina popular para tratamento de doenças. Este estudo teve como objetivo determinar o teor de compostos fenólicos e avaliar a atividade antioxidante in vitro do extrato etanólico e das frações obtidas por partição de S. convoluta. O conteúdo de fenóis totais foi determinado pelo método de Folin-Ciocalteu. O teor de flavonoides totais também foi avaliado. A atividade antioxidante dos extratos foi avaliada usando o método do sequestro do radical DPPH e inibição da auto-oxidação do sistema β-caroteno-ácido linoleico e comparada com os compostos de referência ácido ascórbico, BHA, BHT, quercetina e pirogalol. O conteúdo fenólico total foi de 209,90 ± 19,84 e 61,13 ± 2,50 mg equivalente de ácido gálico/g para os extratos AcOEt e EEB, respectivamente. O conteúdo de flavonoides totais foi de 155,70 ± 6,21 e 62,13 ± 4,10 para os dois extratos, respectivamente. Os extratos AcOEt e EEB apresentaram boas atividades antioxidantes. BHA foi o antioxidante mais efetivo, com um valor de IC50 de 1,62 ± 0,69 µg/mL. Os resultados obtidos mostram que S. convoluta pode ser uma boa fonte de compostos fenólicos antioxidantes. Estudos posteriores serão realizados para se chegar ao isolamento e identificação dos principais constituintes fenólicos dos extratos.

Mechanisms controlling Cu, Fe, Mn, and Co profiles in peat of the Filson Creek Fen, northeastern Minnesota

Science.gov (United States)

Walton-Day, K.; Filipek, L.H.; Papp, C.S.E.

1990-01-01

Filson Creek Fen, located in northeastern Minnesota, overlies a Cu-Ni sulfide deposit. A site in the fen was studied to evaluate the hydrogeochemical mechanisms governing the development of Fe, Mn, Co, and Cu profiles in the peat. At the study site, surface peat approximately 1 m thick is separated from the underlying mineralized bedrock by a 6-12 m thickness of lake and glaciofluvial sediments and till. Concentrations of Fe, Mn, Co, and Cu in peat and major elements in pore water delineate a shallow, relatively oxidized, Cu-rich zone overlying a deeper, reduced, Fe-, Mn-, and Co-rich zone within the peat. Sequential metal extractions from peat samples reveal that 40-55% of the Cu in the shallow zone is associated with organic material, whereas the remaining Cu is distributed between iron-oxide, sulfide, and residual fractions. Sixty to seventy percent of the Fe, Mn, and Co concentrated in the deeper zone occur in the residual phase. The metal profiles and associations probably result from non-steady-state input of metals and detritus into the fen during formation of the peat column. The enrichment of organic-associated Cu in the upper, oxidized zone represents a combination of Cu transported into the fen with detrital plant fragments and soluble Cu, derived from weathering of outcrop and subcrop of the mineral deposit, transported into the fen, and fixed onto organic matter in the peat. The variable stratigraphy of the peat indicates that weathering processes and surface vegetation have changed through time in the fen. The Fe, Mn, and Co maxima at the base of the peat are associated with a maximum in detrital matter content of the peat resulting from a transition between the underlying inorganic sedimentary environment to an organic sedimentary environment. The chemistry of sediments and ground water collected beneath the peat indicate that mobilization of metals from sulfide minerals in the buried mineral deposit or glacial deposits is minimal. Therefore, the

Oligotrophic wetland sediments susceptible to shifts in microbiomes and mercury cycling with dissolved organic matter addition

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Emily B. Graham

2018-04-01

Full Text Available Recent advances have allowed for greater investigation into microbial regulation of mercury toxicity in the environment. In wetlands in particular, dissolved organic matter (DOM may influence methylmercury (MeHg production both through chemical interactions and through substrate effects on microbiomes. We conducted microcosm experiments in two disparate wetland environments (oligotrophic unvegetated and high-C vegetated sediments to examine the impacts of plant leachate and inorganic mercury loadings (20 mg/L HgCl2 on microbiomes and MeHg production in the St. Louis River Estuary. Our research reveals the greater relative capacity for mercury methylation in vegetated over unvegetated sediments. Further, our work shows how mercury cycling in oligotrophic unvegetated sediments may be susceptible to DOM inputs in the St. Louis River Estuary: unvegetated microcosms receiving leachate produced substantially more MeHg than unamended microcosms. We also demonstrate (1 changes in microbiome structure towards Clostridia, (2 metagenomic shifts toward fermentation, and (3 degradation of complex DOM; all of which coincide with elevated net MeHg production in unvegetated microcosms receiving leachate. Together, our work shows the influence of wetland vegetation in controlling MeHg production in the Great Lakes region and provides evidence that this may be due to both enhanced microbial activity as well as differences in microbiome composition.

Seasonal Trace Gas Dynamics on Minerotrophic Fen Peatlands in NE-Germany

Science.gov (United States)

Giebels, Michael; Beyer, Madlen; Augustin, Jürgen; Minke, Merten; Juszczak, Radoszlav; Serba, Tomasz

2010-05-01

In Germany more than 99 % of fens have lost their carbon and nutrient sink function due to heavy drainage and agricultural land use especially during the last decades and thus resulted in compression and heavy peat loss (CHARMAN 2002; JOOSTEN & CLARKE 2002; SUCCOW & JOOSTEN 2001; AUGUSTIN et al. 1996; KUNTZE 1993). Therefore fen peatlands play an important part (4-5 %) in the national anthropogenic trace gas budget. But only a small part of drained and agricultural used fens in NE Germany can be restored. Knowledge of the influence of land use to trace gas exchange is important for mitigation of the climate impact of the anthropogenic peatland use. We study carbon exchanges of several fen peatland use areas between soil and atmosphere at different sites in NE-Germany. Our research covers peatlands of supposed strongly climate forcing land use (cornfield and intensive pasture) and of probably less forcing, alternative types (meadow and extensive pasture) as well as rewetted (formerly drained) areas and near-natural sites like a low-degraded fen and a wetted alder woodland. We measured trace gas fluxes with manual and automatic chambers in periodic routines since spring 2007. The used chamber technique bases on DROESLER (2005). In total we now do research at 22 sites situated in 5 different locations covering agricultural, varying states of rewetted and near-natural treatments. We present results of at least 2 years of measurements and show significant differences in their annual trace gas balances depending on the genesis of the observed sites and the seasonal dynamics. Crosswise comparison of different site treatments combined with the seasonal environmental observations give good hints for the identification of main flux driving parameters. That is that a reduced intensity in land use as a supposed mitigating treatment did not show the expected effect, though a normal meadow treatment surprisingly resulted in the lowest balances in both years. For implementing a

Seasonal Carbon Dynamics on Selected Fen Peatland Sites in NE-Germany

Science.gov (United States)

Giebels, Michael; Beyer, Madlen; Augustin, Jürgen; Minke, Merten; Juszczak, Radoszlav; Serba, Tomasz

2010-05-01

In Germany more than 99 % of fens have lost their carbon and nutrient sink function due to heavy drainage and agricultural land use especially during the last decades and thus resulted in compression and heavy peat loss (CHARMAN 2002; JOOSTEN & CLARKE 2002; SUCCOW & JOOSTEN 2001; AUGUSTIN et al. 1996; KUNTZE 1993). Therefore fen peatlands play an important part (4-5 %) in the national anthropogenic trace gas budget. But only a small part of drained and agricultural used fens in NE Germany can be restored. Knowledge of the influence of land use to trace gas exchange is important for mitigation of the climate impact of the anthropogenic peatland use. We study carbon exchanges of several fen peatland use areas between soil and atmosphere at different sites in NE-Germany. Our research covers peatlands of supposed strongly climate forcing land use (cornfield and intensive pasture) and of probably less forcing, alternative types (meadow and extensive pasture) as well as rewetted (formerly drained) areas and near-natural sites like a low-degraded fen and a wetted alder woodland. We measured trace gas fluxes with manual and automatic chambers in periodic routines since spring 2007. The used chamber technique bases on DROESLER (2005). In total we now do research at 22 sites situated in 5 different locations covering agricultural, varying states of rewetted and near-natural treatments. We present results of at least 2 years of measurements and show significant differences in their annual carbon balances depending on the genesis of the observed sites and the seasonal dynamics. Crosswise comparison of different site treatments combined with the seasonal environmental observations give good hints for the identification of main flux driving parameters. That is that a reduced intensity in land use as a supposed mitigating treatment did not show the expected effect, though a normal meadow treatment surprisingly resulted in the lowest CO2 balances in both years. For implementing a

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

Science.gov (United States)

Morel, A.; Claustre, H.; Gentili, B.

2010-10-01

The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") account for this clarity. The oligotrophic waters of the North and South Pacific gyres, the North and South Atlantic gyres, and the South Indian gyre have been comparatively studied with respect to both [Chl] and CDOM contents, by using 10-year data (1998-2007) of the Sea-viewing Wide field-of-view Sensor (SeaWiFS, NASA). Albeit similar these oligotrophic zones are not identical regarding their [Chl] and CDOM contents, as well as their seasonal cycles. According to the zone, the averaged [Chl] value varies from 0.026 to 0.059 mg m-3, whereas the ay(443) average (the absorption coefficient due to CDOM at 443 nm) is between 0.0033 and 0.0072 m-1. The CDOM-to-[Chl] relative proportions also differ between the zones. The clearest waters, corresponding to the lowest [Chl] and CDOM concentrations, are found near Easter Island and near Mariana Islands in the western part of the North Pacific Ocean. In spite of its low [Chl], the Sargasso Sea presents the highest CDOM content amongst the six zones studied. Except in the North Pacific gyre (near Mariana and south of Hawaii islands), a conspicuous seasonality appears to be the rule in the other 4 gyres and affects both [Chl] and CDOM; both quantities vary in a ratio of about 2 (maximum-to-minimum). Coinciding [Chl] and CDOM peaks occur just after the local winter solstice, which is also the period of the maximal mixed layer depth in these latitudes. It is hypothesized that the vertical transport of unbleached CDOM from the subthermocline layers

Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea

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C. Jeanthon

2011-07-01

Full Text Available Aerobic anoxygenic phototrophic (AAP bacteria play significant roles in the bacterioplankton productivity and biogeochemical cycles of the surface ocean. In this study, we applied both cultivation and mRNA-based molecular methods to explore the diversity of AAP bacteria along an oligotrophic gradient in the Mediterranean Sea in early summer 2008. Colony-forming units obtained on three different agar media were screened for the production of bacteriochlorophyll-a (BChl-a, the light-harvesting pigment of AAP bacteria. BChl-a-containing colonies represented a low part of the cultivable fraction. In total, 54 AAP strains were isolated and the phylogenetic analyses based on their 16S rRNA and pufM genes showed that they were all affiliated to the Alphaproteobacteria. The most frequently isolated strains belonged to Citromicrobium bathyomarinum, and Erythrobacter and Roseovarius species. Most other isolates were related to species not reported to produce BChl-a and/or may represent novel taxa. Direct extraction of RNA from seawater samples enabled the analysis of the expression of pufM, the gene coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis. Clone libraries of pufM gene transcripts revealed that most phylotypes were highly similar to sequences previously recovered from the Mediterranean Sea and a large majority (~94 % was affiliated to the Gammaproteobacteria. The most abundantly detected phylotypes occurred in the western and eastern Mediterranean basins. However, some were exclusively detected in the eastern basin, reflecting the highest diversity of pufM transcripts observed in this ultra-oligotrophic region. To our knowledge, this is the first study to document extensively the diversity of AAP isolates and to unveil the active AAP community in an oligotrophic marine environment. By pointing out the discrepancies

Escaping the oligotrophic gyre? The year-round movements, foraging behaviour and habitat preferences of Murphy’s petrels

OpenAIRE

Clay, Thomas A.; Phillips, Richard A.; Manica, Andrea; Jackson, Hazel A.; Brooke, M. de L.

2017-01-01

The South Pacific Gyre is the world’s largest expanse of oligotrophic ocean and supports communities of endemic gadfly petrels Pterodroma spp., yet little is known about their foraging ecology in this nutrient-poor environment. We tracked Murphy’s petrels Pterodroma ultima with geolocators from Henderson Island, Pitcairn Islands, for 2 consecutive years (2011 to 2013). During pre-laying exodus, petrels travelled south and southwest of the colony, with males travelling further than females to ...

Influência dos compostos fenólicos de especiarias sobre a lipoperoxidação e o perfil lipídico de tecidos de ratos Influence of spices phenolic compounds on lipoperoxidation and lipid profile of rats tissues

Directory of Open Access Journals (Sweden)

Ana Vládia Bandeira Moreira

2004-12-01

Full Text Available OBJETIVO: Este trabalho avaliou o efeito antioxidante dos compostos fenólicos de uma mistura de especiarias (mostarda, canela e erva-doce sobre o metabolismo dos ácidos graxos das séries ômega3 e ômega6. MÉTODOS: Ratos Wistar recém desmamados receberam dieta rica em gorduras essenciais e um chá de especiarias. Após 45 dias, os animais foram sacrificados e tiveram seus tecidos coletados para análise das substâncias reativas ao ácido tiobarbitúrico e perfil lipídico. RESULTADOS: O chá fornecido aos animais apresentou atividade antioxidante equivalente ao hidroxitolueno butilado. Foram identificados no chá, os ácidos fenólicos catecol, salicílico e caféico; as enzimas cicloxigenase e lipoxigenase foram inibidas pelos extratos ricos nestes ácidos fenólicos. O perfil de ácidos graxos apresenta diferença entre os grupos teste e controles. Todos os tecidos dos grupos teste apresentaram menores valores em lipoperoxidação, em comparação aos controles. CONCLUSÃO: Estes dados sugerem, portanto, um efeito antioxidante das substâncias fenólicas identificadas na mistura das especiarias, sobre os ácidos graxos das séries ômega3 e ômega6.OBJECTIVE: This work analyzed the influence of the phenolic compounds from a blend of spices (mustard, cinnamon and anise on the omega3 and omega6 fatty acids metabolism. METHODS: Weaned Wistar rats received a diet rich in essencial lipids and an infusion of blended spices for 45 days. After that period, they were sacrificed their tissues were collected and analized for the TBARS and lipid profile by CGMS. RESULTS: The tea of spices showed an antioxidant activity equivalent to that of the butylated hydroxytoluene. The following phenolic acids were identified in the infusion, using mass chromatography: cathecol, salicilic and cafeic; Lipooxygenase and ciclooxigenase enzymes were inhbited by the phenolic acid extracts. It was observed that the total amount of the fatty acids found in the test

Changing Land Use: The Fens of England. A Case Study in Land Reclamation [And] Student Work Book.

Science.gov (United States)

Laws, Kevin

A social studies unit and student workbook explore changes in land use that have occurred in the Fenlands of England since the time it was first inhabited. Fens are lowlying land which is partially or completely covered with water. The English Fens are located on the eastern side of the British Isles and cover a total area of about 2,000 square…

Microbial Communities as Environmental Indicators of Ecological Disturbance in Restored Carbonate Fen-Results of 10 Years of Studies.

Science.gov (United States)

Mieczan, Tomasz; Tarkowska-Kukuryk, Monika

2017-08-01

Interactions between bacteria and protists are essential to the ecosystem ecology of fens. Until now, however, there has been almost no information on how restoration procedures in carbonate fens affect the functioning of microbial food webs. Changes in vegetation patterns resulting from restoration may take years to be observed, whereas microbial processes display effects even after short-term exposure to changes in environmental conditions caused by restoration. Therefore, microbial processes and patterns can be used as sensitive indicators of changes in environmental conditions. The present study attempts to verify the hypothesis that the species richness and abundance of microbial loop components would differ substantially before and after restoration. The effect of restoration processes on the functioning of the food web was investigated for a 10 years in a carbonate-rich fen, before and after restoration. The restoration procedure (particularly the improvement in hydrological conditions) distinctly modified the taxonomic composition and functioning of microbial food webs. This is reflected in the increased abundance and diversity of testate amoeba, i.e. top predators, within the microbial food web and in the pronounced increase in the abundance of bacteria. This study suggests potential use of microbial loop components as bio-indicators and bio-monitoring tools for hydrological status of fens and concentrations of nutrients. Better understanding of what regulates microbial populations and activity in fens and unravelling of these fundamental mechanisms are particularly critical in order to more accurately predict how fens will respond to global change or anthropogenic disturbances.

Diverse gene cassettes in class 1 integrons of facultative oligotrophic bacteria of River Mahananda,West Bengal, India.

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Ranadhir Chakraborty

Full Text Available BACKGROUND: In this study a large random collection (n=2188 of facultative oligotrophic bacteria, from 90 water samples gathered in three consecutive years (2007-2009 from three different sampling sites of River Mahananda in Siliguri, West Bengal, India, were investigated for the presence of class 1 integrons and sequences of the amplification products. METHODOLOGY/PRINCIPAL FINDINGS: Replica plating method was employed for determining the antibiotic resistance profile of the randomly assorted facultative oligotrophic isolates. Genomic DNA from each isolate was analyzed by PCR for the presence of class 1 integron. Amplicons were cloned and sequenced. Numerical taxonomy and 16S rRNA gene sequence analyses were done to ascertain putative genera of the class 1 integron bearing isolates. Out of 2188 isolates, 1667 (76.19% were antibiotic-resistant comprising of both single-antibiotic resistance (SAR and multiple-antibiotic resistant (MAR, and 521 (23.81% were sensitive to all twelve different antibiotics used in this study. Ninety out of 2188 isolates produced amplicon(s of varying sizes from 0.15 to 3.45 KB. Chi-square (χ(2 test revealed that the possession of class 1 integron in sensitive, SAR and MAR is not equally probable at the 1% level of significance. Diverse antibiotic-resistance gene cassettes, aadA1, aadA2, aadA4, aadA5, dfrA1, dfrA5, dfrA7, dfrA12, dfrA16, dfrA17, dfrA28, dfrA30, dfr-IIe, blaIMP-9, aacA4, Ac-6'-Ib, oxa1, oxa10 and arr2 were detected in 64 isolates. The novel cassettes encoding proteins unrelated to any known antibiotic resistance gene function were identified in 26 isolates. Antibiotic-sensitive isolates have a greater propensity to carry gene cassettes unrelated to known antibiotic-resistance genes. The integron-positive isolates under the class Betaproteobacteria comprised of only two genera, Comamonas and Acidovorax of family Comamonadaceae, while isolates under class Gammaproteobacteria fell under the families

The response of soil organic carbon of a rich fen peatland in interior Alaska to projected climate change.

Science.gov (United States)

Fan, Zhaosheng; David McGuire, Anthony; Turetsky, Merritt R; Harden, Jennifer W; Michael Waddington, James; Kane, Evan S

2013-02-01

It is important to understand the fate of carbon in boreal peatland soils in response to climate change because a substantial change in release of this carbon as CO2 and CH4 could influence the climate system. The goal of this research was to synthesize the results of a field water table manipulation experiment conducted in a boreal rich fen into a process-based model to understand how soil organic carbon (SOC) of the rich fen might respond to projected climate change. This model, the peatland version of the dynamic organic soil Terrestrial Ecosystem Model (peatland DOS-TEM), was calibrated with data collected during 2005-2011 from the control treatment of a boreal rich fen in the Alaska Peatland Experiment (APEX). The performance of the model was validated with the experimental data measured from the raised and lowered water-table treatments of APEX during the same period. The model was then applied to simulate future SOC dynamics of the rich fen control site under various CO2 emission scenarios. The results across these emissions scenarios suggest that the rate of SOC sequestration in the rich fen will increase between year 2012 and 2061 because the effects of warming increase heterotrophic respiration less than they increase carbon inputs via production. However, after 2061, the rate of SOC sequestration will be weakened and, as a result, the rich fen will likely become a carbon source to the atmosphere between 2062 and 2099. During this period, the effects of projected warming increase respiration so that it is greater than carbon inputs via production. Although changes in precipitation alone had relatively little effect on the dynamics of SOC, changes in precipitation did interact with warming to influence SOC dynamics for some climate scenarios. © 2012 Blackwell Publishing Ltd.

The response of soil organic carbon of a rich fen peatland in interior Alaska to projected climate change

Science.gov (United States)

Fan, Zhaosheng; McGuire, Anthony David; Turetsky, Merritt R.; Harden, Jennifer W.; Waddington, James Michael; Kane, Evan S.

2013-01-01

It is important to understand the fate of carbon in boreal peatland soils in response to climate change because a substantial change in release of this carbon as CO2 and CH4 could influence the climate system. The goal of this research was to synthesize the results of a field water table manipulation experiment conducted in a boreal rich fen into a process-based model to understand how soil organic carbon (SOC) of the rich fen might respond to projected climate change. This model, the peatland version of the dynamic organic soil Terrestrial Ecosystem Model (peatland DOS-TEM), was calibrated with data collected during 2005–2011 from the control treatment of a boreal rich fen in the Alaska Peatland Experiment (APEX). The performance of the model was validated with the experimental data measured from the raised and lowered water-table treatments of APEX during the same period. The model was then applied to simulate future SOC dynamics of the rich fen control site under various CO2 emission scenarios. The results across these emissions scenarios suggest that the rate of SOC sequestration in the rich fen will increase between year 2012 and 2061 because the effects of warming increase heterotrophic respiration less than they increase carbon inputs via production. However, after 2061, the rate of SOC sequestration will be weakened and, as a result, the rich fen will likely become a carbon source to the atmosphere between 2062 and 2099. During this period, the effects of projected warming increase respiration so that it is greater than carbon inputs via production. Although changes in precipitation alone had relatively little effect on the dynamics of SOC, changes in precipitation did interact with warming to influence SOC dynamics for some climate scenarios.

Fen Bilgisi Öğretmen Adaylarının Kimya Bilgilerini Günlük Hayatla İlişkilendirebilme Düzeyleri

OpenAIRE

Yadigaroğlu, Yrd. Doç. Dr. Mustafa; DEMİRCİOĞLU, Doç. Dr. Gökhan; DEMİRCİOĞLU, Doç. Dr. Hülya

2017-01-01

Fen eğitiminin temel amaçlarındanbiri, öğrencilerin fen okur-yazarı olmalarını sağlayarak onları günlükyaşantılarında karşılaştıkları fen olaylarına anlam vermelerine yardımcıolmaktır. Günlük hayatla ya da bağlamı ile ilişkilendirilmeyen bilgi öğrencininzihninde her zaman eksik olacaktır. Bunun gerçekleştirilmesinde fen dersleriiçerisinde yer alan kimya önemli bir yere sahiptir. Bu düşünceden hareketleçalışmada, fen bilgisi öğretmen adaylarının kimya bilgilerini günlük hayatlailişkilendirebil...

The distribution and migration of sodium from a reclaimed upland to a constructed fen peatland in a post-mined oil sands landscape.

Science.gov (United States)

Kessel, Eric D; Ketcheson, Scott J; Price, Jonathan S

2018-07-15

Post-mine landscape reclamation of the Athabasca Oil Sands Region requires the use of tailings sand, an abundant mine-waste material that often contains large amounts of sodium (Na + ). Due to the mobility of Na + in groundwater and its effects on vegetation, water quality is a concern when incorporating mine waste materials, especially when attempting to construct groundwater-fed peatlands. This research is the first published account of Na + redistribution in groundwater from a constructed tailings sand upland to an adjacent constructed fen peat deposit (Nikanotee Fen). A permeable petroleum coke layer underlying the fen, extending partway into the upland, was important in directing flow and Na + beneath the peat, as designed. Initially, Na + concentration was highest in the tailings sand (average of 232mgL -1 ) and lowest in fen peat (96mgL -1 ). Precipitation-driven recharge to the upland controlled the mass flux of Na from upland to fen, which ranged from 2 to 13tons Na + per year. The mass flux was highest in the driest summer, in part from dry-period flowpaths that direct groundwater with higher concentrations of Na + into the coke layer, and in part because of the high evapotranspiration loss from the fen in dry periods, which induces upward water flow. With the estimated flux rates of 336mmyr -1 , the Na + arrival time to the fen surface was estimated to be between 4 and 11years. Over the four-year study, average Na + concentrations within the fen rooting zone increased from 87 to 200mgL -1 , and in the tailings sand decreased to 196mgL -1 . The planting of more salt-tolerant vegetation in the fen is recommended, given the potential for Na + accumulation. This study shows reclamation designs can use layered flow system to control the rate, pattern, and timing of solute interactions with surface soil systems. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Para Além do Estado e do Mercado: A Dádiva no Fenômeno dos Sem-Abrigo

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João Aldeia

2014-03-01

Full Text Available Las reflexiones sobre el fenómeno de los sin techo tienden a reproducir las ausencias que el paradigma del don identifica en el pensamiento sobre las sociedades modernas occidentales. Recurrentemente, se considera al Estado y al mercado como las únicas esferas de regulación social y se los interpreta como los espacios de donde derivan las causas estructurales y las posibles soluciones para el fenómeno. Ello no permite una comprensión completa del tema y tampoco una reflexión consistente sobre los modos de minimizar las injusticias de la vida en la calle. Pensar sobre el fenómeno por medio del paradigma del don es relevante porque permite identificar la habitual invisibilización de las relaciones interpersonales no oficiales que caracterizan la vida en la calle, posibilitando, a su vez, la revalorización de estas interacciones en el debate sobre el fenómeno de los sin techo.

Human FEN1 Expression and Solubility Patterson in DNA Replication and Repair

National Research Council Canada - National Science Library

Carrier, Richard

1999-01-01

Flap endo-/exonuclease (FEN1) is a highly conserved protein shown to be one of 10 essential human proteins required for the production of form I DNA following DNA replication from the simian virus 40 (SV40...

The effect of an exceptionally wet summer on methane effluxes from a 15-year re-wetted fen in north-east Germany

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V. Huth

2013-10-01

Full Text Available Re-wetting minerotrophic fens has become an important strategy to mitigate climate change in Germany. However, recent studies report raised methane (CH4 effluxes during the first years after flooding. A minerotrophic fen in north-east Germany that was re-wetted 15 years ago was exposed to exceptionally heavy rainfall and freshwater flooding in August 2011. We measured CH4 effluxes from wetland vegetation stands dominated by Phragmites australis (Cav. Trin. ex Steud., Typha latifolia L. and Carex acutiformis Ehrh., using the closed-chamber method, fortnightly from March 2011 to March 2012 with extra sampling during the flooding. The respective annual effluxes of CH4 (mean ± 1 standard error from the three vegetation types were 18.5 ± 1.3, 21.1 ± 1.2 and 47.5 ± 5.0 g m-2 a-1, with the August effluxes contributing 40 %, 50 % and 10 % of the annual effluxes. Despite the freshwater flooding in August, annual CH4 effluxes from the 15-year re-wetted fen are similar to those reported from pristine fens. These results are promising because they indicate that, although CH4 effluxes are elevated after re-wetting, they may return to values typical for pristine fens after 15 years. Hence, re-wetting can achieve the purpose of reducing greenhouse gas effluxes from drained minerotrophic fens.

Human FEN1 Expression and Solubility Patterson in DNA Replication and Repair

National Research Council Canada - National Science Library

Carrier, Richard

1999-01-01

.... I show that human FEN1 mRNA and protein levels increase in a cell cycle-dependent manner, with peak mRNA and protein levels attained coincident with S phase DNA replication in both primary and transformed cells...

Large deficiency of polonium in the oligotrophic ocean's interior

Science.gov (United States)

Kim, Guebuem

2001-09-01

The naturally occurring radionuclide 210Po is typically deficient relative to its parent 210Pb in the surface ocean due to preferential removal by biota, while in near equilibrium or excess below the surface mixed layer due to rapid regeneration from sinking organic matter. However, a strikingly large deficit of 210Po is observed in the oligotrophic Sargasso Sea's interior. This argues against the general concept that the removal of reactive elements depends on the population of settling particles. A 210Po mass balance model suggests that rather than downward transport, polonium (proxy for S, Se, and Te) is taken up efficiently by bacteria (i.e., cyanobacteria) and transferred to higher trophic levels (i.e., nekton) in this environment. In contrast, in productive areas of the ocean, sulfur group elements seem to reside in the subsurface ocean for much longer periods as taken up by abundant free-living bacteria (non-sinking fine particles). This study sheds new light on global biogeochemical cycling of sulfur group elements in association with microbial roles, and suggests that 210Po may be useful as a tracer of nitrogen fixation in the ocean.

Gravidez na adolescência: um olhar sobre um fenômeno complexo

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Ana Cristina Garcia Dias

2010-04-01

Full Text Available O presente trabalho apresenta uma revisão seletiva e não sistemática da literatura a respeito do fenômeno da gestação na adolescência. Três eixos temáticos orientam a organização do trabalho: (a Riscos e problemas associados à gestação na adolescência; (b Fatores precursores relacionados à gravidez na adolescência; e (c Fatores sócio-culturais associados ao desejo de ser mãe na adolescência. Entre as conclusões, destaca-se que a gravidez na adolescência é uma experiência que pode ter consequências tanto negativas quanto positivas para os adolescentes. Além disso, o fenômeno evidencia a necessidade de intervenções voltadas à saúde sexual e reprodutiva dos adolescentes.

Tracking climate change in oligotrophic mountain lakes: Recent hydrology and productivity synergies in Lago de Sanabria (NW Iberian Peninsula).

Science.gov (United States)

Jambrina-Enríquez, Margarita; Recio, Clemente; Vega, José Carlos; Valero-Garcés, Blas

2017-07-15

Mountain lakes are particularly sensitive to global change as their oligotrophic conditions may be rapidly altered after reaching an ecological threshold, due to increasing human impact and climate change. Sanabria Lake, the largest mountain lake in the Iberian Peninsula and with a recent history of increased human impact in its watershed, provides an opportunity to investigate recent trends in an oligotrophic, hydrologically-open mountain lake, and their relationship with climate, hydrological variability and human pressure. We conducted the first systematic and detailed survey of stable isotope compositions of Sanabria Lake and Tera River together with limnological analyses during 2009-2011. δ 18 O lakewater and δD lakewater seasonal fluctuations are strongly linked to river discharges, and follow the monthly mean isotopic composition of precipitation, which is controlled by NAO dynamics. δ 13 C POM and δ 13 C DIC revealed higher contribution of allochthonous organic matter in winter and spring due to higher river inflow and lower primary productivity. Increased phytoplankton biomass in late summer correlated significantly with higher pH and Chl-a, and higher nutrient input and lower river inflow. However, the small δ 13 C POM seasonal amplitude underlines the stability of the oligotrophic conditions and the isotopic variation in POM and DIC reflect small seasonal fluctuations mostly as a consequence of strong throughflow. The stability of hydrology and productivity patterns is consistent with Holocene and last millennium reconstructions of past limnological changes in Sanabria Lake. The results of this study indicate that trophic state in this hydrologically-open mountain lake is strongly controlled by climate variability, but recent changes in human-land uses have increased sediment delivery and nutrients supply to the lake and have to be considered for management policies. Monitoring surveys including isotope techniques provide snapshots of modern isotope

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

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A. Morel

2010-10-01

Full Text Available The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl] level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance" account for this clarity. The oligotrophic waters of the North and South Pacific gyres, the North and South Atlantic gyres, and the South Indian gyre have been comparatively studied with respect to both [Chl] and CDOM contents, by using 10-year data (1998–2007 of the Sea-viewing Wide field-of-view Sensor (SeaWiFS, NASA. Albeit similar these oligotrophic zones are not identical regarding their [Chl] and CDOM contents, as well as their seasonal cycles. According to the zone, the averaged [Chl] value varies from 0.026 to 0.059 mg m⁻³, whereas the a_y(443 average (the absorption coefficient due to CDOM at 443 nm is between 0.0033 and 0.0072 m⁻¹. The CDOM-to-[Chl] relative proportions also differ between the zones. The clearest waters, corresponding to the lowest [Chl] and CDOM concentrations, are found near Easter Island and near Mariana Islands in the western part of the North Pacific Ocean. In spite of its low [Chl], the Sargasso Sea presents the highest CDOM content amongst the six zones studied. Except in the North Pacific gyre (near Mariana and south of Hawaii islands, a conspicuous seasonality appears to be the rule in the other 4 gyres and affects both [Chl] and CDOM; both quantities vary in a ratio of about 2 (maximum-to-minimum. Coinciding [Chl] and CDOM peaks occur just after the local winter solstice, which is also the period of the maximal mixed layer depth in these latitudes. It is hypothesized that the vertical

Los fenómenos psicológicos no investigados en la comunicación educativa

OpenAIRE

Ortiz-Torres, Emilio Alberto

2017-01-01

Propósito: el artículo tiene por objetivo valorar la importancia del estudio científico de los fenómenos psicológicos la sugestión, la percepción interpersonal y el rumor, los cuales inciden en la comunicación educativa. Tema: el tema que se trabaja es la existencia e influencia de dichos fenómenos subjetivos en los diferentes contextos formativos donde se desarrolla la comunicación interpersonal. Desarrollo: se realiza un análisis teórico sobre la comunicación educativa como concepto interdi...

Landscape history, calcareous fen development and historical events in the Slovak Eastern Carpathians

Czech Academy of Sciences Publication Activity Database

Jamrichová, Eva; Hájková, Petra; Horsák, M.; Rybníčková, E.; Lacina, A.; Hájek, Michal

2014-01-01

Roč. 23, č. 5 (2014), s. 497-513 ISSN 0939-6314 Institutional support: RVO:67985939 Keywords : forest development * spring fen * multi-proxy Subject RIV: EF - Botanics Impact factor: 2.648, year: 2014

Soluble and colloidal iron in the oligotrophic North Atlantic and North Pacific.

Science.gov (United States)

Wu, J; Boyle, E; Sunda, W; Wen, L S

2001-08-03

In the oligotrophic North Atlantic and North Pacific, ultrafiltration studies show that concentrations of soluble iron and soluble iron-binding organic ligands are much lower than previously presumed "dissolved" concentrations, which were operationally defined as that passing through a 0.4-micrometer pore filter. Our studies indicate that substantial portions of the previously presumed "dissolved" iron (and probably also iron-binding ligands) are present in colloidal size range. The soluble iron and iron-binding organic ligands are depleted at the surface and enriched at depth, similar to distributions of major nutrients. By contrast, colloidal iron shows a maximum at the surface and a minimum in the upper nutricline. Our results suggest that "dissolved" iron may be less bioavailable to phytoplankton than previously thought and that iron removal through colloid aggregation and settling should be considered in models of the oceanic iron cycle.

Fen ecohydrologic trajectories in response to groundwater drawdown with edaphic, floristic, and hydrologic feedbacks

Science.gov (United States)

Booth, E.; Steven, L. I.; Bart, D.

2017-12-01

Calcareous fens are unique and often isolated ecosystems of high conservation value worldwide because they provide habitat for many rare plant and animal species. Their identity is inextricably linked to an absolute dependence on a consistent discharge of groundwater that saturates the near surface for most of the growing season leading to the accumulation of carbon as peat or tufa and sequestration of nutrients. The stresses resulting from consistent saturation and low-nutrient availability result in high native plant diversity including very high rare species richness compared to other ecosystems. Decreases in the saturation stress by reduced groundwater inputs (e.g., from nearby pumping) can result in losses of native diversity, decreases in rare-species abundance, and increased invasion by non-native species. As such, fen ecosystems are particularly susceptible to changes in groundwater conditions including reduction in water levels due to nearby groundwater pumping. Trajectories of degradation are complex due to feedbacks between loss of soil organic carbon, changes in soil properties, and plant water use. We present a model of an archetype fen that couples a hydrological niche model with a variably-saturated groundwater flow model to predict changes in vegetation composition in response to different groundwater drawdown scenarios (step change, declining trend, and periodic drawdown during dry periods). The model also includes feedbacks among vegetation composition, plant water use, and soil properties. The hydrological niche models (using surface soil moisture as predictor) and relationships between vegetation composition, plant water use (via stomatal conductance and leaf-area index), and soil hydraulic properties (van Genuchten parameters) were determined based on data collected from six fens in Wisconsin under various states of degradation. Results reveal a complex response to drawdown and provide insight into other ecosystems with linkages between the

The effect of habitat fragmentation and abiotic factors on fen plant occurrence

NARCIS (Netherlands)

Soomers, H.; Karssenberg, D.J.; Verhoeven, J.T.A.; Verweij, P.A.; Wassen, M.J.

2013-01-01

Human landscape modification has led to habitat fragmentation for many species. Habitat fragmentation, leading to isolation, decrease in patch size and increased edge effect, is observed in fen ecosystems that comprise many endangered plant species. However, until now it has remained unclear

The hydrological and geochemical isolation of a freshwater bog within a saline fen in north-eastern Alberta

Directory of Open Access Journals (Sweden)

S.J. Scarlett

2013-10-01

Full Text Available In the oil sands development region near Fort McMurray, Alberta, wetlands cover ~62 % of the landscape, and ~95 % of these wetlands are peatlands. A saline fen was studied as a reference site for peatland reclamation. Despite highly saline conditions, a freshwater bog was observed in the path of local saline groundwater flow. The purpose of this study was to identify the hydrological controls that have allowed the development and persistence of a bog in this setting. The presence of bog vegetation and its dilute water chemistry suggest that saline groundwater from the fen rarely enters the bog, which functions predominantly as a groundwater recharge system. Chloride (Cl– and sodium (Na+ were the dominant ions in fen water, with concentrations averaging 5394 and 2307 mg L-1, respectively, while the concentrations in bog water were 5 and 4 mg L-1, respectively. These concentrations were reflected by salinity and electrical conductivity measurements, which in the fen averaged 9.3 ppt, and 15.8 mS cm-1, respectively, and in the bog averaged 0.1 ppt and 0.3 mS cm-1, respectively. A small ridge in the mineral substratum was found at the fen–bog margin, which created a persistent groundwater mound. Under the dry conditions experienced in early summer, groundwater flow was directed away from the bog at a rate of 14.6 mm day-1. The convex water table at the fen-bog margin impeded flow of saline water into the bog and instead directed it around the bog margin. However, the groundwater mound was eliminated during flooding in autumn, when the horizontal hydraulic gradient across the margin became negligible, suggesting the possibility of saline water ingress into the bog under these conditions.

Diversity of picoeukaryotes at an oligotrophic site off the Northeastern Red Sea Coast.

Science.gov (United States)

Acosta, Francisco; Ngugi, David Kamanda; Stingl, Ulrich

2013-08-20

Picoeukaryotes are protists ≤ 3 μm composed of a wide diversity of taxonomic groups. They are an important constituent of the ocean's microbiota and perform essential ecological roles in marine nutrient and carbon cycles. Despite their importance, the true extent of their diversity has only recently been uncovered by molecular surveys that resulted in the discovery of a substantial number of previously unknown groups. No study on picoeukaryote diversity has been conducted so far in the main Red Sea basin-a unique marine environment characterized by oligotrophic conditions, high levels of irradiance, high salinity and increased water temperature. We sampled surface waters off the coast of the northeastern Red Sea and analyzed the picoeukaryotic diversity using Sanger-based clone libraries of the 18S rRNA gene in order to produce high quality, nearly full-length sequences. The community captured by our approach was dominated by three main phyla, the alveolates, stramenopiles and chlorophytes; members of Radiolaria, Cercozoa and Haptophyta were also found, albeit in low abundances. Photosynthetic organisms were especially diverse and abundant in the sample, confirming the importance of picophytoplankton for primary production in the basin as well as indicating the existence of numerous ecological micro-niches for this trophic level in the upper euphotic zone. Heterotrophic organisms were mostly composed of the presumably parasitic Marine Alveolates (MALV) and the presumably bacterivorous Marine Stramenopiles (MAST) groups. A small number of sequences that did not cluster closely with known clades were also found, especially in the MALV-II group, some of which could potentially belong to novel clades. This study provides the first snapshot of the picoeukaryotic diversity present in surface waters of the Red Sea, hence setting the stage for large-scale surveying and characterization of the eukaryotic diversity in the entire basin. Our results indicate that the

Microbial communities in dark oligotrophic volcanic ice cave ecosystems of Mt. Erebus, Antarctica

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Bradley M. Tebo

2015-03-01

Full Text Available The Earth’s crust hosts a subsurface, dark, and oligotrophic biosphere that is poorly understood in terms of the energy supporting its biomass production and impact on food webs at the Earth’s surface. Dark oligotrophic volcanic ecosystems (DOVEs are good environments for investigations of life in the absence of sunlight as they are poor in organics, rich in chemical reactants and well known for chemical exchange with Earth’s surface systems. Ice caves near the summit of Mt. Erebus (Antarctica offer DOVEs in a polar alpine environment that is starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. We surveyed the microbial communities using PCR, cloning, sequencing and analysis of the small subunit (16S ribosomal and Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RubisCO genes in sediment samples from three different caves, two that are completely dark and one that receives snow-filtered sunlight seasonally. The microbial communities in all three caves are composed primarily of Bacteria and fungi; Archaea were not detected. The bacterial communities from these ice caves display low phylogenetic diversity, but with a remarkable diversity of RubisCO genes including new deeply branching Form I clades, implicating the Calvin-Benson-Bassham cycle as a pathway of CO2 fixation. The microbial communities in one of the dark caves, Warren Cave, which has a remarkably low phylogenetic diversity, were analyzed in more detail to gain a possible perspective on the energetic basis of the microbial ecosystem in the cave. Atmospheric carbon (CO2 and CO, including from volcanic emissions, likely supplies carbon and/or some of the energy requirements of chemoautotrophic microbial communities in Warren Cave and probably other Mt. Erebus ice caves. Our work casts a first glimpse at Mt. Erebus ice caves as natural laboratories for exploring carbon, energy and nutrient sources in the subsurface biosphere and the

Fatty acid desaturase (FADS gene polymorphisms and insulin resistance in association with serum phospholipid polyunsaturated fatty acid composition in healthy Korean men: cross-sectional study

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Yang Long In

2011-04-01

Full Text Available Abstract Background We investigated the relationship between fatty acid desaturase (FADS gene polymorphisms and insulin resistance (IR in association with serum phospholipid polyunsaturated fatty acid (FA composition in healthy Korean men. Methods Healthy men (n = 576, 30 ~ 79 years old were genotyped for rs174537 near FADS1 (FEN1-10154G>T, FADS2 (rs174575C>G, rs2727270C>T, and FADS3 (rs1000778C>T SNPs. Dietary intake, serum phospholipid FA composition and HOMA-IR were measured. Results Fasting insulin and HOMA-IR were significantly higher in the rs174575G allele carriers than the CC homozygotes, but lower in the rs2727270T allele carriers than the CC homozygotes. The proportion of linoleic acid (18:2ω-6, LA was higher in the minor allele carriers of FEN1-10154G>T, rs174575C>G and rs2727270C>T than the major homozygotes, respectively. On the other hand, the proportions of dihomo-γ-linolenic acid (20:3ω-6, DGLA and arachidonic acid (20:4ω-6, AA in serum phospholipids were significantly lower in the minor allele carriers of FEN1-10154 G>T carriers and rs2727270C>T than the major homozygotes respectively. AA was also significantly lower in the rs1000778T allele carriers than the CC homozygotes. HOMA-IR positively correlated with LA and DGLA and negatively with AA/DGLA in total subjects. Interestingly, rs174575G allele carriers showed remarkably higher HOMA-IR than the CC homozygotes when subjects had higher proportions of DLGA (≥1.412% in total serum phospholipid FA composition (P for interaction = 0.009 or of AA (≥4.573% (P for interaction = 0.047. Conclusion HOMA-IR is associated with FADS gene cluster as well as with FA composition in serum phospholipids. Additionally, HOMA-IR may be modulated by the interaction between rs174575C>G and the proportion of DGLA or AA in serum phospholipids.

Filtering fens: mechanisms explaining phosphorus-limited hotspots of biodiversity in wetlands adjacent to heavily fertilized areas.

Science.gov (United States)

Cusell, Casper; Kooijman, Annemieke; Fernandez, Filippo; van Wirdum, Geert; Geurts, Jeroen J M; van Loon, E Emiel; Kalbitz, Karsten; Lamers, Leon P M

2014-05-15

The conservation of biodiverse wetland vegetation, including that of rich fens, has a high priority at a global scale. Although P-eutrophication may strongly decrease biodiversity in rich fens, some well-developed habitats do still survive in highly fertilized regions due to nutrient filtering services of large wetlands. The occurrence of such nutrient gradients is well-known, but the biogeochemical mechanisms that determine these patterns are often unclear. We therefore analyzed chemical speciation and binding of relevant nutrients and minerals in surface waters, soils and plants along such gradients in the large Ramsar nature reserve Weerribben-Wieden in the Netherlands. P-availability was lowest in relatively isolated floating rich fens, where plant N:P ratios indicated P-limitation. P-limitation can persist here despite high P-concentrations in surface waters near the peripheral entry locations, because only a small part of the P-input reaches the more isolated waters and fens. This pattern in P-availability appears to be primarily due to precipitation of Fe-phosphates, which mainly occurs close to entry locations as indicated by decreasing concentrations of Fe- and Al-bound P in the sub-aquatic sediments along this gradient. A further decrease of P-availability is caused by biological sequestration, which occurs throughout the wetland as indicated by equal concentrations of organic P in all sub-aquatic sediments. Our results clearly show that the periphery of large wetlands does indeed act as an efficient P-filter, sustaining the necessary P-limitation in more isolated parts. However, this filtering function does harm the ecological quality of the peripheral parts of the reserve. The filtering mechanisms, such as precipitation of Fe-phosphates and biological uptake of P, are crucial for the conservation and restoration of biodiverse rich fens in wetlands that receive eutrophic water from their surroundings. This seems to implicate that biodiverse wetland

Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

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Valdivia-Anistro, Jorge A.; Eguiarte-Fruns, Luis E.; Delgado-Sapién, Gabriela; Márquez-Zacarías, Pedro; Gasca-Pineda, Jaime; Learned, Jennifer; Elser, James J.; Olmedo-Alvarez, Gabriela; Souza, Valeria

2016-01-01

The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6–15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the

Annual changes of bacterial mortality due to viruses and protists in an oligotrophic coastal environment (NW Mediterranean).

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Boras, Julia A; Sala, M Montserrat; Vázquez-Domínguez, Evaristo; Weinbauer, Markus G; Vaqué, Dolors

2009-05-01

The impact of viruses and protists on bacterioplankton mortality was examined monthly during 2 years (May 2005-April 2007) in an oligotrophic coastal environment (NW Mediterranean Sea). We expected that in such type of system, (i) bacterial losses would be caused mainly by protists, and (ii) lysogeny would be an important type of virus-host interaction. During the study period, viruses and grazers together were responsible for 50.6 +/- 40.1% day(-1) of bacterial standing stock losses (BSS) and 59.7 +/- 44.0% day(-1) of bacterial production losses (BP). Over the first year (May 2005-April 2006), protists were the principal cause of bacterial mortality, removing 29.9 +/- 20.4% day(-1) of BSS and 33.9 +/- 24.3% day(-1) of BP, whereas viral lysis removed 13.5 +/- 17.0% day(-1) of BSS and 12.3 +/- 12.3% day(-1) of BP. During the second year (May 2006-April 2007), viruses caused comparable bacterial losses (29.2 +/- 14.8% day(-1) of BSS and 40.9 +/- 20.7% day(-1) of BP) to protists (28.6 +/- 25.5% day(-1) of BSS and 32.4 +/- 20.0% day(-1) of BP). In 37% of cases higher losses of BP due to viruses than due to protists were found. Lysogenic infection was detected in 11 of 24 samplings. Contrary to our expectations, lytic infections dominated over the two years, and viruses resulted to be a significant source of bacterial mortality in this oligotrophic site.

The influence of vegetation structure on spider species richness, diversity and community organization in the Apšuciems calcareous fen, Latvia

Energy Technology Data Exchange (ETDEWEB)

Štokmane, M.; Spuņģis, V.

2016-07-01

Calcareous fens are considered to be among the most threatened ecosystems of Europe. They are also one of the most diverse habitats as they support an incredibly rich and diverse range of plant and animal species. However, in spite of their diversity, calcareous fens are still poorly investigated, especially when referring to fen invertebrates, such as spiders. Because spiders are good bioindicators, knowledge of their ecology in rare and threatened habitats is of interest. The aim of this study was to document the composition and diversity of spider species, families and foraging guilds in the ground– and grass–layers of the Apšuciems calcareous fen, and to evaluate the influence of vegetation structure on spider community organization. In summer 2012, we collected ground–dwelling spiders using pitfall traps and grass–dwelling spiders using sweep–netting. A total of 2,937 spider individuals belonging to 19 families and 80 species was collected in the Apšuciems fen. Our results indicate that spider species and families tend to be stratified across the vertical structure of the habitat; the spider composition in the ground stratum differed from that in the grass stratum. On the contrary, however, the spider foraging guild structure between the ground–layer and the grass–layer was similar. Each of the two studied strata presented similar guilds in similar proportions. Our results also showed that spider composition differed considerably between fen parts and that much of this variability could be explained by the architectural properties of the habitat. More diverse vegetation generally supported a higher number of spider species. (Author)

Análisis comparativo de compuestos fenólicos totales y actividad antioxidante de cuatro marcas de tisanas de Hibiscus sabdariffa (Malvaceae comercializadas en Costa Rica

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Melissa Agüero

2014-01-01

Full Text Available Las tisanas de rosa de Jamaica (Hibiscus sabdariffa son consumidas en Costa Rica por su conocido efecto cardioprotector asociado a la presencia de compuestos fenólicos, principalmente antocianinas. Este trabajo estableció diferencias en el perfil de compuestos fenólicos y su actividad anti-radical entre diferentes comercializadores de tisanas de Hibiscus sabdariffa en Costa Rica. Se identificaron cualitativamente taninos, flavonoides y antocianinas. Se cuantificó la cantidad total de compuestos fenólicos por el método de Folin-Ciocalteu y se cuantificó la actividad antioxidante con el método de DPPH. Todas las marcas comerciales demostraron presencia de compuestos fenólicos, incluyendo antocianinas; sin embargo, se encontraron diferencias significativas en el contenido de compuestos fenólicos y actividad anti-radical, entre los diferentes productores de tisanas. Por ello, se concluye que en el mercado costarricense, el perfil en compuestos fenólicos de las tisanas en estudio varía de acuerdo con el productor.

Predicting aquatic macrophyte occurrence in soft-water oligotrophic lakes (Pyrenees mountain range

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Cristina Pulido

2014-08-01

Full Text Available Distribution of aquatic macrophytes in lakes is related to geographical, morphological, catchment and water chemistry variables as well as human impacts, which modify the original environment. Here, we aim at building statistical models to establish the ecological niches of 11 aquatic macrophytes (10 different phanerogams and the genus Nitella from oligotrophic soft-water lakes and infer their ecological requirements and environmental constraints at the southernmost limit of their distribution. Macrophyte occurrence and environmental variables were obtained from 86 non-exploited oligotrophic soft-water lakes from the Pyrenees (Southern Europe; 42º50´N, 1º00´E; macrophytes inhabited 55 of these lakes. Optimum ranges and macrophyte occurrence were predicted in relation to 18 geographical, morphological, catchment and water chemistry variables using univariate and multivariate logistic models. Lakes at low altitude, in vegetated catchments and with low water concentration of NO3- and SO4-2, were the most suitable to host macrophytes. In general, individual species of aquatic macrophytes showed clear patterns of segregation along conductivity and pH gradients, although the specific combination of variables selected in the best models explaining their occurrence differed among species.  Based on the species response to pH and conductivity, we found Isoetes lacustris have its optimum in waters with low conductivity and pH (i.e. negative monotonic response. In contrast, Callitriche palustris, Ranunculus aquatilis, Subularia aquatica, Nitella spp., and Myriophyllum alterniflorum showed an optimum at intermediate values (i.e. unimodal response, whereas Potamogeton berchtoldii, Potamogeton alpinus, and Ranunculus trichophyllus as species had their optimum at relatively high water pH and conductivity (i.e. positive monotonic response. This pattern has been observed in other regions for the same species, although with different optima and tolerance

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

OpenAIRE

A. Morel; H. Claustre; B. Gentili

2010-01-01

The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") account ...

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

OpenAIRE

Morel, A.; Claustre, H.; Gentili, B.

2010-01-01

The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") acc...

Experiencias para observar el fenómeno de fluorescencia con luz ultravioleta

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Heredia Avalos, S.

2008-09-01

Full Text Available La fluorescencia tiene lugar cuando una sustancia emite luz visible al absorber radiación de una longitud de onda menor, como por ejemplo luz ultravioleta. La diferencia entre la energía absorbida (del fotón ultravioleta y la emitida (del fotón visible se disipa en forma de calor. Se dice que la sustancia posee fluorescenciacuando este proceso es muy rápido; si es más lento se dice que la sustancia posee fosforescencia. A continuación se describen varias experiencias sencillas para poner de manifiesto el fenómeno de fluorescencia. Todas ellas requieren de reactivos y materiales fácilmente accesibles y asequibles y se pueden realizar con alumnos de secundaria o de bachillerato para poner de manifiesto este fenómeno. Además, también se propone una experiencia en la que se observa la reversibilidad de las reacciones químicas ácido-base a través de la fluorescencia.

Fenómenos de transporte : un curso introductorio

OpenAIRE

Betancourt Grajales, Ramiro

1991-01-01

Fenómenos de transporte, es el nombre colectivo que se da al estudio sistemático e integrado de tres áreas clásicas de la ciencia de la Ingeniería : 1) Transporte de Energía o Calor, 2) Transporte de Masa o Difusión, y 3) Transporte de Cantidad de Movimiento o Impulso (Momentum en Inglés), o Dinámica de Fluidos. Debido a que con frecuencia el transporte de masa y de calor ocurren en un fluido, algunos planes de estudio incluyen estos procesos en su tratamiento de la mecánica de fluidos....

A cryptic targeting signal creates a mitochondrial FEN1 isoform with tailed R-Loop binding properties.

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Lawrence Kazak

Full Text Available A growing number of DNA transacting proteins is found in the nucleus and in mitochondria, including the DNA repair and replication protein Flap endonuclease 1, FEN1. Here we show a truncated FEN1 isoform is generated by alternative translation initiation, exposing a mitochondrial targeting signal. The shortened form of FEN1, which we term FENMIT, localizes to mitochondria, based on import into isolated organelles, immunocytochemistry and subcellular fractionation. In vitro FENMIT binds to flap structures containing a 5' RNA flap, and prefers such substrates to single-stranded RNA. FENMIT can also bind to R-loops, and to a lesser extent to D-loops. Exposing human cells to ethidium bromide results in the generation of RNA/DNA hybrids near the origin of mitochondrial DNA replication. FENMIT is recruited to the DNA under these conditions, and is released by RNase treatment. Moreover, high levels of recombinant FENMIT expression inhibit mtDNA replication, following ethidium bromide treatment. These findings suggest FENMIT interacts with RNA/DNA hybrids in mitochondrial DNA, such as those found at the origin of replication.

Compostos fenólicos totais, atividade antioxidante e antifúngica demultimisturas enriquecidas com a microalga Spirulina platensis

OpenAIRE

Bierhals, Vânia da Silva; Machado, Vanessa Goulart; Echevenguá, Walesca Oliveira; Costa, Jorge Alberto Vieira; Furlong, Eliana Badiale

2009-01-01

Com o objetivo de avaliar o conteúdo fenólico e as atividades antioxidantes e antifúngicas de multimisturas enriquecidas com Spirulina platensis, foram formuladas quatro multimisturas com farelo de arroz ou trigo, duas contendo Spirulina platensis e duas com sementes de girassol. Os compostos fenólicos foram estimados pela técnica de Folin-Ciocalteau. A atividade antioxidante foi avaliada por meio de inibição do radical livre DPPH e a atividade antifúngica foi analisada por meio de ensaio de ...

Avaliação da atividade antioxidante dos compostos fenólicos naturalmente presentes em subprodutos do pseudofruto de caju (Anacardium occidentale L. Evaluation of the Antioxidant Activity of Phenolic Compounds Naturally Contained in By-products of the Cashew Apple (Anacardium occidentale L.

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Priscila Regina Bolelli Broinizi

2007-12-01

Full Text Available O presente trabalho teve como proposta avaliar a capacidade antioxidante do bagaço e do extrato bruto concentrado (EBC do pedúnculo de caju, tendo em vista o seu aproveitamento. O potencial antioxidante dos extratos aquoso (EAq e alcoólico (EAlc e das frações de ácidos fenólicos livres (AFL e esterificadas (solúvel AFS e insolúvel AFI desses subprodutos do pedúnculo de caju clone CCP-76 foi avaliado em sistema beta-caroteno/ácido linoléico, pelo teste de varredura de radical livre [2,2 difenil-1-pricril-hidrazil (DPPH•] e de Rancimat. Além do mais, o conteúdo de fenólicos totais e o perfil de ácidos fenólicos foram determinados usando-se o reagente de Folin-Ciocateau e por cromatografia gasosa, respectivamente. O EAq e a fração AFL dos subprodutos apresentaram o maior conteúdo de fenólicos. As frações de ácidos fenólicos exibiram expressiva atividade antioxidante, superior aos extratos estudados nos sistemas beta-caroteno e DPPH. Entretanto no teste Rancimat, os extratos apresentaram maior proteção à oxidação em relação às frações e ao BHT. Nas frações foram identificados os ácidos gálico, ferúlico, caféico, protocatecuico, quínico, cinâmico, gentíssico, p-cumárico e salicílico, os quais lhes conferem o potencial antioxidante. Estes resultados caracterizaram in vitro o potencial antioxidante do bagaço e do EBC do pedúnculo de caju clone CCP-76.This study aimed to determine the antioxidant capacity of cashew apple pulp and raw concentrated extract. The antioxidant potential of aqueous (EAq and alcoholic (EAlc extracts and of free phenolic acids (FPA and esterified (soluble - SPA and insoluble - IPA fractions of the by-products of the cashew apple clone CCP-76 were evaluated in a beta-carotene-linoleate system by the free radical [2,2-diphenyl-1-picrylhydrazyl (DPPH•] scavenging assay and the Rancimat test. In addition, the total phenolic content and phenolic acid profile were determined using

The influence of vegetation structure on spider species richness, diversity and community organization in the Apšuciems calcareous fen, Latvia

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Štokmane, M.

2016-07-01

Full Text Available Calcareous fens are considered to be among the most threatened ecosystems of Europe. They are also one of the most diverse habitats as they support an incredibly rich and diverse range of plant and animal species. However, in spite of their diversity, calcareous fens are still poorly investigated, especially when referring to fen invertebrates, such as spiders. Because spiders are good bioindicators, knowledge of their ecology in rare and threatened habitats is of interest. The aim of this study was to document the composition and diversity of spider species, families and foraging guilds in the ground– and grass–layers of the Apšuciems calcareous fen, and to evaluate the influence of vegetation structure on spider community organization. In summer 2012, we collected ground–dwelling spiders using pitfall traps and grass–dwelling spiders using sweep–netting. A total of 2,937 spider individuals belonging to 19 families and 80 species was collected in the Apšuciems fen. Our results indicate that spider species and families tend to be stratified across the vertical structure of the habitat; the spider composition in the ground stratum differed from that in the grass stratum. On the contrary, however, the spider foraging guild structure between the ground–layer and the grass–layer was similar. Each of the two studied strata presented similar guilds in similar proportions. Our results also showed that spider composition differed considerably between fen parts and that much of this variability could be explained by the architectural properties of the habitat. More diverse vegetation generally supported a higher number of spider species.

Response of benthic opportunistic polychaetes and amphipods index to different perturbations in coastal oligotrophic areas (Canary archipelago, North East Atlantic Ocean)

OpenAIRE

Riera, Rodrigo; de-la-Ossa-Carretero, Jose Antonio

2014-01-01

Oligotrophic areas harbour low macrofaunal abundance and patchy distribution. In these areas it is necessary to test the reliability of biological indicators, especially those based on taxonomic sufficiency where the level of identification is balanced against the need for ecological information and could affect the efficiency of bioindicators. The BOPA (benthic opportunistic polychaetes and amphipods) index was applied in five coastal areas subjected to different perturbations (aquaculture, ...

Short-Term Summer Inundation as a Measure to Counteract Acidification in Rich Fens

NARCIS (Netherlands)

Mettrop, I.S.; Cusell, C.; Kooijman, A.M.; Lamers, L.P.M.

2015-01-01

In regions with intensive agriculture, water level fluctuation in wetlands has generally become constricted within narrow limits. Water authorities are, however, considering the re-establishment of fluctuating water levels as a management tool in biodiverse, base-rich fens (‘rich fens’). This

A conceptual model for the blooming behavior and persistence of the benthic mat-forming diatom Didymosphenia geminata in oligotrophic streams

Science.gov (United States)

Cullis, James D. S.; Gillis, Carole-Anne; Bothwell, Max L.; Kilroy, Cathy; Packman, Aaron; Hassan, Marwan

2012-06-01

The benthic, mat-forming diatomDidymosphenia geminata has the unique ability to produce large amounts of algal biomass under oligotrophic conditions in cold, fast flowing streams and rivers. This presents an ecological paradox that challenges our current understanding of stream ecosystem dynamics. Our understanding of the drivers of D. geminata ecology is still limited. Here we present a conceptual model for the blooming behavior and persistence of this species to advance scientific understanding of strategies for life in fast flowing oligotrophic waters and support the design of future research and mitigation measures for nuisance algal blooms. The conceptual model is based on a synthesis of data and ideas from a range of disciplines including hydrology, geomorphology, biogeochemistry, and ecology. The conceptual model highlights the role of water chemistry, river morphology, and flow thresholds in defining the habitat window for D. geminata. We propose that bed disturbance is a primary control on accumulation and persistence of D. geminataand that the removal threshold can be determined by synthesizing site-specific information on hydrology and geomorphology. Further, we propose that a key to understanding the didymo paradox is the separation of cellular reproduction and mat morphology with specific controls acting in respect of the different processes.

Annual cycle of methane emission from a boreal fen measured by the eddy covariance technique

International Nuclear Information System (INIS)

Rinne, Janne.; Pihlatie, Mari; Haapanala, Sami; Vesala, Timo; Riutta, Terhi; Tuittila, Eeva-Stiina; Aurela, Mika; Tuovinen, Juha-Pekka

2007-01-01

The northern wetlands are one of the major sources of methane into the atmosphere. We measured annual methane emission from a boreal minerotrophic fen, Siikaneva, by the eddy covariance method. The average wintertime emissions were below 1 mg/m 2 /h, and the summertime emissions about 3.5 mg/m 2 /h. The water table depth did have any clear effect on methane emissions. During most of the year the emission depended on the temperature of peat below the water table. However, during the high and late summer the emission was independent on peat temperature as well. No diurnal cycle of methane flux was found. The total annual emission from the Siikaneva site was 12.6 g/m 2 . The emissions of the snow free period contributed 91% to the annual emission. The emission pulse during the snow melting period was clearly detectable but of minor importance adding only less than 3% to the annual emission. Over 20% of the carbon assimilated during the year as carbon dioxide was emitted as methane. Thus methane emission is an important component of the carbon balance of the Siikaneva fen. This indicates need of taking methane into account when studying carbon balances of northern fen ecosystems

Contrasting species-environment relationships in communities of testate amoebae, bryophytes and vascular plants along the fen-bog gradient.

Science.gov (United States)

Lamentowicz, Mariusz; Lamentowicz, Lukasz; van der Knaap, Willem O; Gabka, Maciej; Mitchell, Edward A D

2010-04-01

We studied the vegetation, testate amoebae and abiotic variables (depth of the water table, pH, electrical conductivity, Ca and Mg concentrations of water extracted from mosses) along the bog to extremely rich fen gradient in sub-alpine peatlands of the Upper Engadine (Swiss Alps). Testate amoeba diversity was correlated to that of mosses but not of vascular plants. Diversity peaked in rich fen for testate amoebae and in extremely rich fen for mosses, while for testate amoebae and mosses it was lowest in bog but for vascular plants in extremely rich fen. Multiple factor and redundancy analyses (RDA) revealed a stronger correlation of testate amoebae than of vegetation to water table and hydrochemical variables and relatively strong correlation between testate amoeba and moss community data. In RDA, hydrochemical variables explained a higher proportion of the testate amoeba and moss data than water table depth. Abiotic variables explained a higher percentage of the species data for testate amoebae (30.3% or 19.5% for binary data) than for mosses (13.4%) and vascular plants (10%). These results show that (1) vascular plant, moss and testate amoeba communities respond differently to ecological gradients in peatlands and (2) testate amoebae are more strongly related than vascular plants to the abiotic factors at the mire surface. These differences are related to vertical trophic gradients and associated niche differentiation.

Eletricidade Atmosférica e Fenômenos Correlatos

OpenAIRE

Tavares, M.; Santiago, M.A.M

2002-01-01

A qualquer momento, existem cerca de 2000 tempestades com relâmpagos nos cêus em torno do mundo. Estima-se que as tempestades combinadas produzem aproximadamente 100 descargas de raios por segundo, cada uma com temperatura em torno de 30.0000ºC - mais quente que a superfície do Sol. Esse trabalho apresenta aos leitores alguns fenômenos elêtricos na atmosfera e estratosfera. Tais eventos fazem parte de um sugerido circuito elêtrico atmosfêrico global e estão conectados à pesquisa de plasmas. A...

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

International Nuclear Information System (INIS)

Geurts, Jeroen J.M.; Sarneel, Judith M.; Willers, Bart J.C.; Roelofs, Jan G.M.; Verhoeven, Jos T.A.; Lamers, Leon P.M.

2009-01-01

Both eutrophication and SO 4 pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO 4 were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO 4 addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO 4 pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO 4 pollution, sulphide toxicity and nutrient availability.

Biology, ecology, use, conservation and cultivation of round-leaved sundew (Drosera rotundifolia L.: a review

Directory of Open Access Journals (Sweden)

B. Baranyai

2016-09-01

Full Text Available Drosera rotundifolia is a perennial insectivorous herb which occupies open, wet, oligotrophic habitats such as acidic bogs and poor fens, and specifically grows in Sphagnum-dominated communities. Since mediaeval times the species has been collected from natural habitats and used as a remedy for coughs and pulmonary diseases. Due to the substantial decline of Drosera habitat, the plant has been protected in most European countries since the 1980s, which means that wild D. rotundifolia has become unavailable to the pharmaceutical industry. The persistent demand has stimulated research into the cultivation of Drosera in several European countries. These studies have shown that Drosera cultivation is time-consuming and not (yet cost-effective, and there is a need for the development of cultivation methods. This article reviews the morphology, distribution, ecology and reproduction of Drosera rotundifolia; outlines its commercial use and nature conservation requirements; and describes previous research on its propagation and cultivation.

Produção de mudas de cultivares de alface utilizando duas espumas fenólicas em Altamira, Pará

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Alzirio Lino Couto

2015-06-01

Full Text Available O sucesso de qualquer produção comercial de hortaliças inicia-se com a produção de mudas. A espuma fenólica tem se mostrado um interessante e prático substrato para este processo. A utilização deste produto depende de uma lavagem precedente para reduzir a acidez. Porém, já é possível encontrar à venda espumas fenólicas com pH próximo. Por isso o objetivo deste trabalho foi avaliar a produção de mudas de cultivares de alface utilizando duas espumas fenólicas em Altamira, Pará. O delineamento constou de um esquema fatorial 2 (substratos x 6 (cultivares. Os dois substratos foram as espumas fenólicas Green Up®, com pH 6.0 (± 0.5., e a outra com pH 2.6 (± 0.5. As cultivares avaliadas foram: Alcione, Amanda, Lucy Brown, Caipira, Multiblond 3 e Solaris. Foi avaliada porcentagem de germinação, índice de velocidade de emergência, altura da planta e número de folhas. Houve diferença significativa para altura da planta em função dos substratos testados. A porcentagem de germinação mais elevada foi obtida com a espuma fenólica sem tratamento. A cultivar Caipira foi a que teve o menor desempenho na germinação. Para todas as variáveis analisadas, a cultivar Lucy Brown apresentou os melhores resultados em ambos os substratos.

Net ecosystem exchange in a sedge-sphagnum fen at the South of West Siberia, Russia

Science.gov (United States)

Dyukarev, Egor

2017-04-01

The model of net ecosystem exchange was used to study the influence of different environmental factors and to calculate daily and growing season carbon budget for minerotrophic fen at South of West Siberia, Russia. Minerotrophic sedge-sphagnum fen occupies the central part of the Bakcharskoe bog. The model uses air and soil temperature, incoming photosynthetically active radiation, and leaf area index as the explanatory factors for gross primary production, heterotrophic and autotrophic respiration. The model coefficients were calibrated using data collected by automated soil CO2 flux system with clear long-term chamber. The studied ecosystem is a sink of carbon according to modelling and observation results. This study was supported by Russian Foundation for Basic Researches (grant numbers 16-07-01205 and 16-45-700562.

Measurement of 54Fe(n,2n)53Fe cross section near threshold

International Nuclear Information System (INIS)

Smither, R.K.; Greenwood, L.R.

1984-01-01

A series of experiments were performed at the Princeton Plasma Physics Laboratory to measure the cross section of the 54 Fe(n,2n) 53 Fe reaction near threshold. Measurements were made at 6 different neutron energies and cover the 1 MeV energy range from threshold (13.64 MeV) to 14.64 MeV. The 54 Fe(n,2n) cross section was measured relative to the 27 Al(n,p) 27 Mg cross section to an accuracy of a few percent. These accurate cross-section measurements will be useful in calculating damage caused by 14 MeV D-T plasma neutrons in Fe and calculating the production of the long-lived 53 Mn nuclei that account for much of the buildup of long-lived radioactivity in steel structures and other ferrous materials used in the construction of fusion reactors. They will also play an important part in a new method for measuring the plasma ion temperature of a D-T plasma

Water level, vegetation composition, and plant productivity explain greenhouse gas fluxes in temperate cutover fens after inundation

Science.gov (United States)

Minke, Merten; Augustin, Jürgen; Burlo, Andrei; Yarmashuk, Tatsiana; Chuvashova, Hanna; Thiele, Annett; Freibauer, Annette; Tikhonov, Vitalij; Hoffmann, Mathias

2016-07-01

Peat extraction leaves a land surface with a strong relief of deep cutover areas and higher ridges. Rewetting inundates the deep parts, while less deeply extracted zones remain at or above the water level. In temperate fens the flooded areas are colonized by helophytes such as Eriophorum angustifolium, Carex spp., Typha latifolia or Phragmites australis dependent on water depth. Reeds of Typha and Phragmites are reported as large sources of methane, but data on net CO2 uptake are contradictory for Typha and rare for Phragmites. Here, we analyze the effect of vegetation, water level and nutrient conditions on greenhouse gas (GHG) emissions for representative vegetation types along water level gradients at two rewetted cutover fens (mesotrophic and eutrophic) in Belarus. Greenhouse gas emissions were measured campaign-wise with manual chambers every 2 to 4 weeks for 2 years and interpolated by modelling. All sites had negligible nitrous oxide exchange rates. Most sites were carbon sinks and small GHG sources. Methane emissions generally increased with net ecosystem CO2 uptake. Mesotrophic small sedge reeds with water table around the land surface were small GHG sources in the range of 2.3 to 4.2 t CO2 eq. ha-1 yr-1. Eutrophic tall sedge - Typha latifolia reeds on newly formed floating mats were substantial net GHG emitters in the range of 25.1 to 39.1 t CO2 eq. ha-1 yr. They represent transient vegetation stages. Phragmites reeds ranged between -1.7 to 4.2 t CO2 eq. ha-1 yr-1 with an overall mean GHG emission of 1.3 t CO2 eq. ha-1 yr-1. The annual CO2 balance was best explained by vegetation biomass, which includes the role of vegetation composition and species. Methane emissions were obviously driven by biological activity of vegetation and soil organisms. Shallow flooding of cutover temperate fens is a suitable measure to arrive at low GHG emissions. Phragmites australis establishment should be promoted in deeper flooded areas and will lead to moderate, but

A first principles calculations of structural, electronic, magnetic and dynamical properties of mononitrides FeN and CoN

International Nuclear Information System (INIS)

Soni, Himadri R.; Mankad, Venu; Gupta, Sanjeev K.; Jha, Prafulla K.

2012-01-01

Highlights: ► We present spin dependent bandstructure, structural and magnetic moment of FeN/CoN. ► The PDC, PHDOS, spin effect on phonons suggests ZB is preferred at ambient pressure. ► Spin calculation offers an opportunity to understand the role of spin on phonons. - Abstract: Using first principles density functional theoretical calculations, the present paper reports a systematic nonspin and spin polarized total energy calculations of the lattice dynamical and a number of other properties such as band structure, structural and magnetic moment of two mononitrides FeN and CoN. The phonon dispersion curves and phonon density of states in the case of FeN and CoN have been determined for the first time and discussed. The structural and dynamical calculations suggest that the zinc blende structure is preferred at ambient pressure for both compounds. The rocksalt FeN has a nonzero magnetic moment while for FeN in zinc blende phase, it is either zero or very small. The zinc blende phase for both compounds is nonmagnetic. The spin calculation offers an intensive opportunity to understand the role of spin on the phonon properties of two mononitrides. Majority of the modes are sensitive to the effect of spin due to the modification of lattice constant. In this work we reveal that spin modifies the interionic interactions and local structure and leads to a flexible lattice which can be used for the functional materials design.

O fenómeno do Fansubbing em inglês: principais normas de tradução e legendagem

OpenAIRE

Sousa, Inês Fernandes e

2011-01-01

Tese de mestrado, Tradução, Universidade de Lisboa, Faculdade de Letras, 2012 Este trabalho enquadra-se no âmbito dos Estudos Descritivos de Tradução, mais concretamente, nos conceitos de norma e estratégia de tradução e teve como objectivo estudar algumas das principais estratégias e regularidades evidenciadas pelo fenómeno de “fansubbing”. Este fenómeno corresponde ao trabalho de equipas amadoras especializadas na tradução para legendagem predominantemente em inglês de desenh...

Metódica: Articulación sistema teórico, fenómeno y procesos en el objeto de estudio. Una perspectiva desde el fenómeno pobreza

Directory of Open Access Journals (Sweden)

Yajaira Jiménez Zabala

2011-10-01

Full Text Available En este artículo discutimos la visión metódica que toma como apoyo el pivote entre lo cualitativo, lo cuantitativo y el orden de complejidad, en un enfoque plurimetódico, a través del cual se construyó la visión de la pobreza como objeto de estudio. Tal selección, está justificada en tanto se entiende la pobreza como un fenómeno social complejo, por las diversas aristas que le identifican. La combinación de los enfoques metodológicos permitió la aprehensión de los diferentes aspectos del fenómeno y de sus interrelaciones en las representaciones de los actores sociales vinculados con el estudio. Lo cualitativo, se entiende como la simbiosis de prácticas interpretativas, que no privilegia una metodología sobre otra. Lo cuantitativo estuvo referido al uso de indicadores derivados de los soportes referenciales del problema; el orden de complejidad, atendió a la manifestación de lo simple en tanto nodo tensional complejo, que requiere una mirada diferente para su comprensión e interpretación.

A decade of boreal rich fen greenhouse gas fluxes in response to natural and experimental water table variability

Science.gov (United States)

Olefeldt, David; Euskirchen, Eugénie S.; Harden, Jennifer W.; Kane, Evan S.; McGuire, A. David; Waldrop, Mark P.; Turetsky, Merritt R.

2017-01-01

Rich fens are common boreal ecosystems with distinct hydrology, biogeochemistry and ecology that influence their carbon (C) balance. We present growing season soil chamber methane emission (FCH4), ecosystem respiration (ER), net ecosystem exchange (NEE) and gross primary production (GPP) fluxes from a 9-years water table manipulation experiment in an Alaskan rich fen. The study included major flood and drought years, where wetting and drying treatments further modified the severity of droughts. Results support previous findings from peatlands that drought causes reduced magnitude of growing season FCH4, GPP and NEE, thus reducing or reversing their C sink function. Experimentally exacerbated droughts further reduced the capacity for the fen to act as a C sink by causing shifts in vegetation and thus reducing magnitude of maximum growing season GPP in subsequent flood years by ~15% compared to control plots. Conversely, water table position had only a weak influence on ER, but dominant contribution to ER switched from autotrophic respiration in wet years to heterotrophic in dry years. Droughts did not cause inter-annual lag effects on ER in this rich fen, as has been observed in several nutrient-poor peatlands. While ER was dependent on soil temperatures at 2 cm depth, FCH4 was linked to soil temperatures at 25 cm. Inter-annual variability of deep soil temperatures was in turn dependent on wetness rather than air temperature, and higher FCH4 in flooded years was thus equally due to increased methane production at depth and decreased methane oxidation near the surface. Short-term fluctuations in wetness caused significant lag effects on FCH4, but droughts caused no inter-annual lag effects on FCH4. Our results show that frequency and severity of droughts and floods can have characteristic effects on the exchange of greenhouse gases, and emphasize the need to project future hydrological regimes in rich fens.

Composição fenólica de ligninas dioxano determinadas pela reação oxidativa com o nitrobenzeno

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Fukushima Romualdo Shigueo

2003-01-01

Full Text Available A correta quantificação da concentração de lignina em plantas forrageiras, pelo método espectrofotométrico, pressupõe a existência de um padrão de referência. Um padrão de referência deve ter composição fenólica semelhante à da lignina da parede celular. O objetivo deste trabalho foi verificar se ligninas extraídas com solução ácida de dioxano para serem utilizadas como padrão de referência, apresentariam variação na composição fenólica da mesma maneira que a lignina da parede celular. Amostras de parede celular de "bromegrass", milho e trevo-vermelho foram submetidas ao método para extração de ligninas com solução ácida de dioxano. A composição fenólica das ligninas foi analisada mediante oxidação alcalina pelo nitrobenzeno com posterior separação dos componentes monoméricos via HPLC. As ligninas extraídas confirmaram a existência de variação na composição fenólica da mesma maneira às ligninas intactas presentes na parede celular e de substancial presença de ácidos cinâmicos nas ligninas de gramíneas. No que diz respeito à composição fenólica, ligninas extraídas com solução ácida de dioxano podem ser consideradas potenciais padrões de referência paras as análises espectrofotométricas.

Watershed-Induced Limnological and Microbial Status in Two Oligotrophic Andean Lakes Exposed to the Same Climatic Scenario

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Alex Echeverría-Vega

2018-03-01

Full Text Available Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity. We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively and the major fraction corresponded to Anoxygenic Phototrophs (AP represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes.

Watershed-Induced Limnological and Microbial Status in Two Oligotrophic Andean Lakes Exposed to the Same Climatic Scenario.

Science.gov (United States)

Echeverría-Vega, Alex; Chong, Guillermo; Serrano, Antonio E; Guajardo, Mariela; Encalada, Olga; Parro, Victor; Blanco, Yolanda; Rivas, Luis; Rose, Kevin C; Moreno-Paz, Mercedes; Luque, José A; Cabrol, Nathalie A; Demergasso, Cecilia S

2018-01-01

Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others) affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity). We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively) and the major fraction corresponded to Anoxygenic Phototrophs (AP) represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes.

Watershed-Induced Limnological and Microbial Status in Two Oligotrophic Andean Lakes Exposed to the Same Climatic Scenario

Science.gov (United States)

Echeverría-Vega, Alex; Chong, Guillermo; Serrano, Antonio E.; Guajardo, Mariela; Encalada, Olga; Parro, Victor; Blanco, Yolanda; Rivas, Luis; Rose, Kevin C.; Moreno-Paz, Mercedes; Luque, José A.; Cabrol, Nathalie A.; Demergasso, Cecilia S.

2018-01-01

Laguna Negra and Lo Encañado are two oligotrophic Andean lakes forming part of the system fed by meltwater from distinct glacial tongues of the Echaurren glacier in central Chile, which is in a recession period. The recent increase in temperature and decline in precipitation have led to an increase of glacial meltwater and sediments entering these lakes. Although the lacustrine systems are also hydrogeologically connected, the limnology of the lakes is strongly controlled by the surface processes related to the respective sub-watersheds and hydrology. Watershed characteristics (area and length, slope, lithology, resistance to erosion, among others) affect the chemical and physical characteristics of both lakes (e.g., nutrient concentration and turbidity). We studied physical and chemical variables and performed 16S rRNA amplicon sequencing to determine the specific microbial signature of the lakes. The transparency, temperature, turbidity and concentrations of chlorophyll-a, dissolved organic matter, nutrients and the total number of cells, revealed the different status of both lakes at the time of sampling. The predominant bacterial groups in both lakes were Proteobacteria, Verrucomicrobia, and Bacteroidetes. Interestingly, the contribution of phototrophs was significantly higher in LN compared to LE (13 and 4% respectively) and the major fraction corresponded to Anoxygenic Phototrophs (AP) represented by Chloroflexi, Alpha, and Betaproteobacteria. Multivariate analyses showed that the nutrient levels and the light availability of both lakes, which finally depend on the hydrological characteristics of the respective watersheds, explain the differential community composition/function. The abundance of a diverse photoheterotrophic bacterioplankton community suggests that the ability to utilize solar energy along with organic and inorganic substrates is a key function in these oligotrophic mountain lakes. PMID:29556224

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

Energy Technology Data Exchange (ETDEWEB)

Geurts, Jeroen J.M., E-mail: j.geurts@b-ware.e [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); B-WARE Research Centre, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Sarneel, Judith M. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Willers, Bart J.C.; Roelofs, Jan G.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Verhoeven, Jos T.A. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Lamers, Leon P.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)

2009-07-15

Both eutrophication and SO{sub 4} pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO{sub 4} were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO{sub 4} addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO{sub 4} pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO{sub 4} pollution, sulphide toxicity and nutrient availability.

Potential for hydrogen-oxidizing chemolithoautotrophic and diazotrophic populations to initiate biofilm formation in oligotrophic, deep terrestrial subsurface waters.

Science.gov (United States)

Wu, Xiaofen; Pedersen, Karsten; Edlund, Johanna; Eriksson, Lena; Åström, Mats; Andersson, Anders F; Bertilsson, Stefan; Dopson, Mark

2017-03-23

Deep terrestrial biosphere waters are separated from the light-driven surface by the time required to percolate to the subsurface. Despite biofilms being the dominant form of microbial life in many natural environments, they have received little attention in the oligotrophic and anaerobic waters found in deep bedrock fractures. This study is the first to use community DNA sequencing to describe biofilm formation under in situ conditions in the deep terrestrial biosphere. In this study, flow cells were attached to boreholes containing either "modern marine" or "old saline" waters of different origin and degree of isolation from the light-driven surface of the earth. Using 16S rRNA gene sequencing, we showed that planktonic and attached populations were dissimilar while gene frequencies in the metagenomes suggested that hydrogen-fed, carbon dioxide- and nitrogen-fixing populations were responsible for biofilm formation across the two aquifers. Metagenome analyses further suggested that only a subset of the populations were able to attach and produce an extracellular polysaccharide matrix. Initial biofilm formation is thus likely to be mediated by a few bacterial populations which were similar to Epsilonproteobacteria, Deltaproteobacteria, Betaproteobacteria, Verrucomicrobia, and unclassified bacteria. Populations potentially capable of attaching to a surface and to produce extracellular polysaccharide matrix for attachment were identified in the terrestrial deep biosphere. Our results suggest that the biofilm populations were taxonomically distinct from the planktonic community and were enriched in populations with a chemolithoautotrophic and diazotrophic metabolism coupling hydrogen oxidation to energy conservation under oligotrophic conditions.

a fenómenos epidemiológicos

Directory of Open Access Journals (Sweden)

Carlos Arturo Castro Castro

2005-01-01

Full Text Available En este artículo se presentan avances del proyecto de investigación modelación y simulación computacional usando sistemas de información geográfica (SIG con dinámicas de sistemas aplicados a fenómenos epidemiológicos con el cual se han abordado los principales modelos matemáticos usados en epidemiología (susceptible- infectado-recuperado: SIR, susceptible-infectado-recuperado-susceptible: SIRS, susceptible-infectado-susceptible: SIS, para su integración, espacialización y simulación usando diferentes técnicas computacionales con el fin de modelar factores críticos en la propagación de epidemias. Para correr el modelo, se tomaron los datos de una epidemia de asma en el distrito de Manhattan de Nueva York, del tutotial de ARCGIS® versión 8.3.

Dynamics of biochemical processes and redox conditions in geochemically linked landscapes of oligotrophic bogs

Science.gov (United States)

Inisheva, L. I.; Szajdak, L.; Sergeeva, M. A.

2016-04-01

The biological activity in oligotrophic peatlands at the margins of the Vasyugan Mire has been studied. It is shown found that differently directed biochemical processes manifest themselves in the entire peat profile down to the underlying mineral substrate. Their activity is highly variable. It is argued that the notion about active and inert layers in peat soils is only applicable for the description of their water regime. The degree of the biochemical activity is specified by the physical soil properties. As a result of the biochemical processes, a micromosaic aerobic-anaerobic medium is developed under the surface waterlogged layer of peat deposits. This layer contains the gas phase, including oxygen. It is concluded that the organic and mineral parts of peat bogs represent a single functional system of a genetic peat profile with a clear record of the history of its development.

Water flow and solute transport in floating fen root mats

Science.gov (United States)

Stofberg, Sija F.; EATM van der Zee, Sjoerd

2015-04-01

Floating fens are valuable wetlands, found in North-Western Europe, that are formed by floating root mats when old turf ponds are colonized by plants. These terrestrialization ecosystems are known for their biodiversity and the presence of rare plant species, and the root mats reveal different vegetation zones at a small scale. The vegetation zones are a result of strong gradients in abiotic conditions, including groundwater dynamics, nutrients and pH. To prevent irreversible drought effects such as land subsidence and mineralization of peat, water management involves import of water from elsewhere to maintain constant surface water levels. Imported water may have elevated levels of salinity during dry summers, and salt exposure may threaten the vegetation. To assess the risk of exposure of the rare plant species to salinity, the hydrology of such root mats must be understood. Physical properties of root mats have scarcely been investigated. We have measured soil characteristics, hydraulic conductivity, vertical root mat movement and groundwater dynamics in a floating root mat in the nature reserve Nieuwkoopse Plassen, in the Netherlands. The root mat mostly consists of roots and organic material, in which the soil has a high saturated water content, and strongly varies in its stage of decomposition. We have found a distinct negative correlation between degree of decomposition and hydraulic conductivity, similar to observations for bogs in the literature. Our results show that the relatively young, thin edge of the root mat that colonizes the surface water has a high hydraulic conductivity and floats in the surface water, resulting in very small groundwater fluctuations within the root mat. The older part of the root mat, that is connected to the deeper peat layers is hydrologically more isolated and the material has a lower conductivity. Here, the groundwater fluctuates strongly with atmospheric forcing. The zones of hydraulic properties and vegetation, appear to

Fenómenos que Organizan el Límite (Phenomena that Organize Limits

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María Teresa Sánchez

2007-03-01

Full Text Available En este artículo se pone de manifiesto la presencia de los fenómenos de aproximación organizados por una definición de límite en el caso de las sucesiones de números reales y de las funciones reales de una variable real. La exposición incluye la caracterización de tales fenómenos, una descripción del análisis comparativo desarrollado en base a ellos entre dos definiciones formales de límite de sucesión y función, y una síntesis del estudio llevado a cabo sobre una muestra intencional de libros de texto de matemáticas.In this paper we show the presence of the phenomena of approximation organized by a definition of limit in the cases of the successions of real numbers and the real functions of one real variable. The exposition includes the characterization of such phenomena, a description of the comparative analysis, developed using them, between two formal definitions of limit of succession and function, and a synthesis of the study carried out on an intentional sample of mathematics textbooks.

The DNA Repair Repertoire of Mycobacterium smegmatis FenA Includes the Incision of DNA 5' Flaps and the Removal of 5' Adenylylated Products of Aborted Nick Ligation.

Science.gov (United States)

Uson, Maria Loressa; Ghosh, Shreya; Shuman, Stewart

2017-09-01

We characterize Mycobacterium smegmatis FenA as a manganese-dependent 5'-flap endonuclease homologous to the 5'-exonuclease of DNA polymerase I. FenA incises a nicked 5' flap between the first and second nucleotides of the duplex segment to yield a 1-nucleotide gapped DNA, which is then further resected in dinucleotide steps. Initial FenA cleavage at a Y-flap or nick occurs between the first and second nucleotides of the duplex. However, when the template 3' single strand is eliminated to create a 5'-tailed duplex, FenA incision shifts to between the second and third nucleotides. A double-flap substrate with a mobile junction (mimicking limited strand displacement synthesis during gap repair) is preferentially incised as the 1-nucleotide 3'-flap isomer, with the scissile phosphodiester shifted by one nucleotide versus a static double flap. FenA efficiently removes the 5' App(dN) terminus of an aborted nick ligation reaction intermediate, thereby highlighting FenA as an agent of repair of such lesions, which are formed under a variety of circumstances by bacterial NAD + -dependent DNA ligases and especially by mycobacterial DNA ligases D and C. IMPORTANCE Structure-specific DNA endonucleases are implicated in bacterial DNA replication, repair, and recombination, yet there is scant knowledge of the roster and catalytic repertoire of such nucleases in Mycobacteria This study identifies M. smegmatis FenA as a stand-alone endonuclease homologous to the 5'-exonuclease domain of mycobacterial DNA polymerase 1. FenA incises 5' flaps, 5' nicks, and 5' App(dN) intermediates of aborted nick ligation. The isolated N-terminal domain of M. smegmatis Pol1 is also shown to be a flap endonuclease. Copyright © 2017 American Society for Microbiology.

Cold-Active, Heterotrophic Bacteria from the Highly Oligotrophic Waters of Lake Vanda, Antarctica

Directory of Open Access Journals (Sweden)

Nicole A. Vander Schaaf

2015-07-01

Full Text Available The permanently ice-covered lakes of the McMurdo Dry Valleys, Antarctica are distinctive ecosystems that consist strictly of microbial communities. In this study, water samples were collected from Lake Vanda, a stratified Dry Valley lake whose upper waters (from just below the ice cover to nearly 60 m are highly oligotrophic, and used to establish enrichment cultures. Six strains of psychrotolerant, heterotrophic bacteria were isolated from lake water samples from a depth of 50 or 55 m. Phylogenetic analyses showed the Lake Vanda strains to be species of Nocardiaceae, Caulobacteraceae, Sphingomonadaceae, and Bradyrhizobiaceae. All Lake Vanda strains grew at temperatures near or below 0 °C, but optimal growth occurred from 18 to 24 °C. Some strains showed significant halotolerance, but no strains required NaCl for growth. The isolates described herein include cold-active species not previously reported from Dry Valley lakes, and their physiological and phylogenetic characterization broadens our understanding of these limnologically unique lakes.

The food additive vanillic acid controls transgene expression in mammalian cells and mice.

Science.gov (United States)

Gitzinger, Marc; Kemmer, Christian; Fluri, David A; El-Baba, Marie Daoud; Weber, Wilfried; Fussenegger, Martin

2012-03-01

Trigger-inducible transcription-control devices that reversibly fine-tune transgene expression in response to molecular cues have significantly advanced the rational reprogramming of mammalian cells. When designed for use in future gene- and cell-based therapies the trigger molecules have to be carefully chosen in order to provide maximum specificity, minimal side-effects and optimal pharmacokinetics in a mammalian organism. Capitalizing on control components that enable Caulobacter crescentus to metabolize vanillic acid originating from lignin degradation that occurs in its oligotrophic freshwater habitat, we have designed synthetic devices that specifically adjust transgene expression in mammalian cells when exposed to vanillic acid. Even in mice transgene expression was robust, precise and tunable in response to vanillic acid. As a licensed food additive that is regularly consumed by humans via flavoured convenience food and specific fresh vegetable and fruits, vanillic acid can be considered as a safe trigger molecule that could be used for diet-controlled transgene expression in future gene- and cell-based therapies.

Research of Ancient Architectures in Jin-Fen Area Based on GIS&BIM Technology

Science.gov (United States)

Jia, Jing; Zheng, Qiuhong; Gao, Huiying; Sun, Hai

2017-05-01

The number of well-preserved ancient buildings located in Shanxi Province, enjoying the absolute maximum proportion of ancient architectures in China, is about 18418, among which, 9053 buildings have the structural style of wood frame. The value of the application of BIM (Building Information Modeling) and GIS (Geographic Information System) is gradually probed and testified in the corresponding fields of ancient architecture’s spatial distribution information management, routine maintenance and special conservation & restoration, the evaluation and simulation of related disasters, such as earthquake. The research objects are ancient architectures in JIN-FEN area, which were first investigated by Sicheng LIANG and recorded in his work of “Chinese ancient architectures survey report”. The research objects, i.e. the ancient architectures in Jin-Fen area include those in Sicheng LIANG’s investigation, and further adjustments were made through authors’ on-site investigation and literature searching & collection. During this research process, the spatial distributing Geodatabase of research objects is established utilizing GIS. The BIM components library for ancient buildings is formed combining on-site investigation data and precedent classic works, such as “Yingzao Fashi”, a treatise on architectural methods in Song Dynasty, “Yongle Encyclopedia” and “Gongcheng Zuofa Zeli”, case collections of engineering practice, by the Ministry of Construction of Qing Dynasty. A building of Guangsheng temple in Hongtong county is selected as an example to elaborate the BIM model construction process based on the BIM components library for ancient buildings. Based on the foregoing work results of spatial distribution data, attribute data of features, 3D graphic information and parametric building information model, the information management system for ancient architectures in Jin-Fen Area, utilizing GIS&BIM technology, could be constructed to support the

Environmental and Physiographic Controls on Inter-Growing Season Variability of Carbon Dioxide and Water Vapour Fluxes in a Minerotrophic Fen

Science.gov (United States)

van der Kamp, G.; Sonnentag, O.; Chen, J. M.; Barr, A.; Hedstrom, N.; Granger, R.

2008-12-01

The interaction of fens with groundwater is spatially and temporally highly variable in response to meteorological conditions, resulting in frequent changes of groundwater fluxes in both vertical and lateral directions (flow reversals) across the mineral soil-peat boundary. However, despite the importance of the topographic and hydrogeological setting of fens, no study has been reported in the literature that explores a fen's atmospheric CO2 and energy flux densities under contrasting meteorological conditions in response to its physiographic setting. In our contribution we report four years of growing season eddy covariance and supporting measurements from the Canada Fluxnet-BERMS fen (formerly BOREAS southern peatland) in Saskatchewan, Canada. We first analyze hydrological data along two piezometer transects across the mineral soil-peat boundary with the objective of assessing changes in water table configuration and thus hydraulic gradients, indicating flow reversals, in response to dry and wet meteorological conditions. Next we quantify and compare growing season totals and diurnal and daily variations in evapotranspiration (ET) and net ecosystem exchange (NEE) and its component fluxes gross ecosystem productivity (GPP) and terrestrial ecosystem respiration (TER) to identify their controls with a major focus on water table depth. While ET growing season totals were similar (~ 310 mm) under dry and wet meteorological conditions, the CO2 sink- source strength of Sandhill fen varied substantially from carbon neutral (NEE = -2 [+-7] g C m-2 per growing season) under dry meteorological condition (2003) to a moderate CO2- sink with NEE ranging between 157 [+- 10] and 190 [+- 11] g C m-2 per growing season under wet meteorological conditions (2004, 2005, and 2006). Using a process-oriented ecosystem model, BEPS-TerrainLab, we investigate how different canopy components at Sandhill contribute to total ET and GPP, and thus water use efficiency, under dry and wet

Violência como fenômeno intrínseco à cultura política brasileira

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Antonio M. Soares

2016-06-01

Full Text Available Este artigo problematiza o conceito de violência e suas mutações através dos tempos. Como fenômeno cultural, a violência é construída na sociedade e se processa de forma a romper com os próprios códigos de ordens produzidos por ela. No caso do Brasil a violência se mostra intrínseca ao processo de formação da sociedade brasileira, estando presente nas lógicas autoritárias e na imposição cultural desde os tempos da colonização. A violência emerge como uma agressão ao indivíduo e ao coletivo, ela aniquila o sentido da política e desabilita o mundo comum. As interpretações presentes neste trabalho buscam aprofundar as análises sobre a violência enquanto fenômeno social e cultural, redimensionando os efeitos que ela produz para a condição humana e suas associações com as dimensões da civilidade, incivilidade e descivilidade. Neste contexto, destacaremos como o fenômeno da violência se afirmou como uma dimensão estrutural e cultural da formação da sociedade brasileira, como ele se revela na contemporaneidade, nos jogos de poder, nas relações de força e no movimento de fronteiras tênues entre o legal e o ilegal.

Análisis de la influencia del fenómeno del ciberterrorismo en las dinámicas de seguridad de la Unión Europea

OpenAIRE

Torres Pedraza, Julián Alejandro

2014-01-01

El fenómeno del ciberterrorismo se constituye como una nueva amenaza a la seguridad internacional, este fenómeno es el resultado de distintos procesos en el sistema internacional como el de la globalización. La definición del concepto se establece por la convergencia entre el ciberespacio y el terrorismo. El objetivo de esta investigación es explicar las distintas dimensiones del ciberterrorismo, métodos de ataque, acciones pasadas, propósito del fenómeno, situación actual y vulnerabilidades....

Complete Genome Sequence of Bradyrhizobium sp. S23321: Insights into Symbiosis Evolution in Soil Oligotrophs

Science.gov (United States)

Okubo, Takashi; Tsukui, Takahiro; Maita, Hiroko; Okamoto, Shinobu; Oshima, Kenshiro; Fujisawa, Takatomo; Saito, Akihiro; Futamata, Hiroyuki; Hattori, Reiko; Shimomura, Yumi; Haruta, Shin; Morimoto, Sho; Wang, Yong; Sakai, Yoriko; Hattori, Masahira; Aizawa, Shin-ichi; Nagashima, Kenji V. P.; Masuda, Sachiko; Hattori, Tsutomu; Yamashita, Akifumi; Bao, Zhihua; Hayatsu, Masahito; Kajiya-Kanegae, Hiromi; Yoshinaga, Ikuo; Sakamoto, Kazunori; Toyota, Koki; Nakao, Mitsuteru; Kohara, Mitsuyo; Anda, Mizue; Niwa, Rieko; Jung-Hwan, Park; Sameshima-Saito, Reiko; Tokuda, Shin-ichi; Yamamoto, Sumiko; Yamamoto, Syuji; Yokoyama, Tadashi; Akutsu, Tomoko; Nakamura, Yasukazu; Nakahira-Yanaka, Yuka; Hoshino, Yuko Takada; Hirakawa, Hideki; Mitsui, Hisayuki; Terasawa, Kimihiro; Itakura, Manabu; Sato, Shusei; Ikeda-Ohtsubo, Wakako; Sakakura, Natsuko; Kaminuma, Eli; Minamisawa, Kiwamu

2012-01-01

Bradyrhizobium sp. S23321 is an oligotrophic bacterium isolated from paddy field soil. Although S23321 is phylogenetically close to Bradyrhizobium japonicum USDA110, a legume symbiont, it is unable to induce root nodules in siratro, a legume often used for testing Nod factor-dependent nodulation. The genome of S23321 is a single circular chromosome, 7,231,841 bp in length, with an average GC content of 64.3%. The genome contains 6,898 potential protein-encoding genes, one set of rRNA genes, and 45 tRNA genes. Comparison of the genome structure between S23321 and USDA110 showed strong colinearity; however, the symbiosis islands present in USDA110 were absent in S23321, whose genome lacked a chaperonin gene cluster (groELS3) for symbiosis regulation found in USDA110. A comparison of sequences around the tRNA-Val gene strongly suggested that S23321 contains an ancestral-type genome that precedes the acquisition of a symbiosis island by horizontal gene transfer. Although S23321 contains a nif (nitrogen fixation) gene cluster, the organization, homology, and phylogeny of the genes in this cluster were more similar to those of photosynthetic bradyrhizobia ORS278 and BTAi1 than to those on the symbiosis island of USDA110. In addition, we found genes encoding a complete photosynthetic system, many ABC transporters for amino acids and oligopeptides, two types (polar and lateral) of flagella, multiple respiratory chains, and a system for lignin monomer catabolism in the S23321 genome. These features suggest that S23321 is able to adapt to a wide range of environments, probably including low-nutrient conditions, with multiple survival strategies in soil and rhizosphere. PMID:22452844

CO dissociation on magnetic Fen clusters

KAUST Repository

Jedidi, Abdesslem

2014-01-01

This work theoretically investigates the CO dissociation on Fen nanoparticles, for n in the range of 1-65, focusing on size dependence in the context of the initial step of the Fischer-Tropsch reaction. CO adsorbs molecularly through its C-end on a triangular facet of the nanoparticle. Dissociation becomes easier when the cluster size increases. Then, the C atom is bonded to a square facet that is generated as a result of the adsorption if it does not yet exist in the bare cluster, while the O atom is adsorbed on a triangular facet. In the most stable situation, the two adsorbed atoms remain close together, both having in common one shared first-neighbor iron atom. There is a partial spin quenching of the neighboring Fe atoms, which become more positively charged than the other Fe atoms. The shared surface iron atom resembles a metal-cation from a complex. Despite the small size of the iron cluster considered, fluctuations due to specific configurations do not influence properties for n > 25 and global trends seem significant.

Compostos fenólicos e capacidade antioxidante de cultivares de uvas Vitis labrusca L. e Vitis vinifera L. Phenolic compounds and antioxidant activity of Vitis labrusca and Vitis vinifera cultivars

Directory of Open Access Journals (Sweden)

Lucile Tiemi Abe

2007-06-01

Full Text Available O conteúdo de compostos fenólicos, incluindo resveratrol, antocianinas e outros flavonóides, e a capacidade antioxidante de cinco cultivares de uvas produzidas em Minas Gerais foram determinados. O conteúdo de fenólicos totais, determinado através do método de Folin-Ciocalteau variou significativamente, entre 65 ± 1 e 390 ± 30 mg equivalentes de ácido gálico.100 g -1 de amostra base úmida (b.u.. O conteúdo de antocianinas totais quantificado por CLAE variou entre 6,7 ± 0,2 e 154 ± 4 mg equivalentes de cianidina.100 g -1 (b.u.. Outros flavonóides encontrados foram catequina, epicatequina, quercetina, caempferol além dos ácidos hidroxicinâmicos. O resveratrol foi encontrado em três cultivares, variando entre 0,022 ± 0,001 e 0,60 ± 0,03 mg.100 g -1 (b.u.. A capacidade antioxidante foi analisada usando o método de seqüestro de radicais livres do DPPH (2,2-difenil-1-picrilhidrazila, que variou entre 2,7 ± 0,1 e 19 ± 2 µmoles equivalentes de Trolox.g -1 de amostra (b.u., mostrando boa correlação com o conteúdo de fenólicos totais. As uvas tintas de coloração mais escura apresentaram maior conteúdo de antocianinas, e conseqüentemente maior teor de fenólicos totais e capacidade antioxidante.Phenolic compounds including resveratrol, anthocyanins and other flavonoids and antioxidant capacity were evaluated for five grape cultivars cultivated in Minas Gerais (Brazil. The content of total phenolic determined by the Folin Ciocalteau method varied significantly, from 65 ± 1 to 390 ± 30 mg gallic acid equivalents.100 g -1 of FW (Fresh Weight. The content of total anthocyanins quantified by HPLC varied from 6.7 ± 0.2 to 154 ± 4 mg of cyanidin equivalents.100 g -1 FW. Resveratrol was found in three cultivars, in contents from 0.022 ± 0.001 to 0.60 ± 0.03 mg.100 g¹ of FW. In addition to hydroxicynnamic acids, other flavonoids such as catechin, epicatechin, quercetin and kaempferol were also present. The antioxidant

Response of anaerobic carbon cycling to water table manipulation in an Alaskan rich fen

Science.gov (United States)

Kane, E.S.; Chivers, M.R.; Turetsky, M.R.; Treat, C.C.; Petersen, D.G.; Waldrop, M.; Harden, J.W.; McGuire, A.D.

2013-01-01

To test the effects of altered hydrology on organic soil decomposition, we investigated CO2 and CH4 production potential of rich-fen peat (mean surface pH = 6.3) collected from a field water table manipulation experiment including control, raised and lowered water table treatments. Mean anaerobic CO2 production potential at 10 cm depth (14.1 ± 0.9 μmol C g−1 d−1) was as high as aerobic CO2 production potential (10.6 ± 1.5 μmol C g−1 d−1), while CH4 production was low (mean of 7.8 ± 1.5 nmol C g−1 d−1). Denitrification enzyme activity indicated a very high denitrification potential (197 ± 23 μg N g−1 d−1), but net NO-3 reduction suggested this was a relatively minor pathway for anaerobic CO2 production. Abundances of denitrifier genes (nirK and nosZ) did not change across water table treatments. SO2-4 reduction also did not appear to be an important pathway for anaerobic CO2 production. The net accumulation of acetate and formate as decomposition end products in the raised water table treatment suggested that fermentation was a significant pathway for carbon mineralization, even in the presence of NO-3. Dissolved organic carbon (DOC) concentrations were the strongest predictors of potential anaerobic and aerobic CO2 production. Across all water table treatments, the CO2:CH4 ratio increased with initial DOC leachate concentrations. While the field water table treatment did not have a significant effect on mean CO2 or CH4 production potential, the CO2:CH4 ratio was highest in shallow peat incubations from the drained treatment. These data suggest that with continued drying or with a more variable water table, anaerobic CO2 production may be favored over CH4 production in this rich fen. Future research examining the potential for dissolved organic substances to facilitate anaerobic respiration, or alternative redox processes that limit the effectiveness of organic acids as substrates in anaerobic metabolism, would help explain additional

El fenómeno del acoso laboral entre los trabajadores de la universidad O fenômeno mobbing entre os trabalhadores da universidade The phenomenon of mobbing among university employees

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Fernando Justicia Justicia

2007-12-01

Full Text Available El objetivo del artículo es realizar una descripción del fenómemo mobbing -acoso laboral- en el contexto de la universidad. Los trabajos realizadossobre este problema no son muy prolíficos lo que puede explicar la gran dificultad para caracterizar el fenómeno en el ámbito universitario. En el presente trabajo presentamos los niveles de incidencia del acoso laboral entre la población universitaria, los tipos de acoso más frecuentes y los efectos producidos en las víctimas, con la finalidad de caracterizar y definir el problema. Al mismo tiempo, intentamos conocer la influencia de determinadas variables como la edad, género y tiempo de victimización. En este sentido, y de acuerdo con otros estudios realizados, encontramos diferencias estadísticas en función del género de las víctimas. Del mismo modo, los resultados apuntan que la frecuencia y duración del acoso laboral afectan negativamente a las víctimas provocando un empeoramiento de los efectos derivados del acoso.O objetivo deste artigo é realizar uma descrição do fenômeno mobbing -tormento e persecução no lugar do trabalho- no contexto da universidade. Há poucos trabalhos realizados sob este problema nos contextos de educação superior o que pode explicar a grande dificuldade para caracterizar o fenômeno no âmbito universitário. Neste artigo apresentamos os níveis de incidência entre a população universitária, os tipos de mobbing mais freqüentes e os efeitos produzidos nas vítimas com a finalidade de caracterizar e definir o problema. Ao mesmo tempo, tentamos conhecer a influência de determinadas variáveis tais como a idade, gênero ou o tempo de exposição ao fenômeno. Neste sentido, e em concordância com outros estudos realizados, encontramos diferenças estatísticas em função do gênero das vítimas. De igual forma, os dados apontam que a freqüência e duração da situação de persecução no trabalho afetam negativamente as vítimas provocando

Rehabilitation of acidified and eutrophied fens in The Netherlands : Effects of hydrologic manipulation and liming

NARCIS (Netherlands)

Beltman, B.; Broek, T. van den; Barendregt, A.; Bootsma, M.C.; Grootjans, A.P.

Mosaic fen communities with many rare plant species were outcompeted by fast-growing bryophyte stands (Sphagnum flexuosum/Sphagnum fallax and Polytrichum commune). Eutrophication and acidification were the main causes. Management experiments were carried out to set back this succession by restoring

Biochemical processes of oligotrophic peat deposits of Vasyugan Mire

Science.gov (United States)

Inisheva, L. I.; Sergeeva, M. A.

2009-04-01

The problem of peat and mire ecosystems functioning and their rational use is the main problem of biosphere study. This problem also refers to forecasting of biosphere changes results which are global and anthropogenic. According to many scientists' research the portion of mires in earth carbon balance is about 15% of world's stock. The aim of this study is to investigate biochemical processes in oligotrophic deposits in North-eastern part of Vasyugan Mire. The investigations were made on the territory of scientific-research ground (56˚ 03´ and 56˚ 57´ NL, 82˚ 22´ and 82˚ 42´ EL). It is situated between two rivers Bakchar and Iksa (in outskirts of the village Polynyanka, Bakchar region, Tomsk oblast). Evolution of investigated mire massif began with the domination of eutrophic phytocenosis - Filicinae, then sedge. Later transfer into oligotrophic phase was accompanied by formation of meter high-moor peat deposit. The age of three-meter peat deposit reaches four thousand years. Biochemical processes of carbon cycle cover the whole peat deposit, but the process activity and its direction in different layers are defined by genesis and duration of peat formation. So, the number of cellulose-fermenting aerobes in researched peat deposits ranges from 16.8 to 75.5 million CFU/g, and anaerobic bacteria from 9.6 to 48.6 million CFU/g. The high number of aerobes is characteristic for high water levels, organizing by raised bog peats. Their number decreases along the profile in 1.7 - 2 times. The number of microflora in peat deposit is defined by the position in the landscape profile (different geneses), by the depth, by hydrothermic conditions of years and individual months. But microflora activity shows along all depth of peat deposit. We found the same in the process of studying of micromycete complex structure. There was revealed either active component micromycete complex - mycelium, or inert one - spores in a meter layer of peat deposit. If mushrooms

Variable nutrient stoichiometry (carbon:nitrogen:phosphorus) across trophic levels determines community and ecosystem properties in an oligotrophic mangrove system.

Science.gov (United States)

Scharler, U M; Ulanowicz, R E; Fogel, M L; Wooller, M J; Jacobson-Meyers, M E; Lovelock, C E; Feller, I C; Frischer, M; Lee, R; McKee, K; Romero, I C; Schmit, J P; Shearer, C

2015-11-01

Our study investigated the carbon:nitrogen:phosphorus (C:N:P) stoichiometry of mangrove island of the Mesoamerican Barrier Reef (Twin Cays, Belize). The C:N:P of abiotic and biotic components of this oligotrophic ecosystem was measured and served to build networks of nutrient flows for three distinct mangrove forest zones (tall seaward fringing forest, inland dwarf forests and a transitional zone). Between forest zones, the stoichiometry of primary producers, heterotrophs and abiotic components did not change significantly, but there was a significant difference in C:N:P, and C, N, and P biomass, between the functional groups mangrove trees, other primary producers, heterotrophs, and abiotic components. C:N:P decreased with increasing trophic level. Nutrient recycling in the food webs was highest for P, and high transfer efficiencies between trophic levels of P and N also indicated an overall shortage of these nutrients when compared to C. Heterotrophs were sometimes, but not always, limited by the same nutrient as the primary producers. Mangrove trees and the primary tree consumers were P limited, whereas the invertebrates consuming leaf litter and detritus were N limited. Most compartments were limited by P or N (not by C), and the relative depletion rate of food sources was fastest for P. P transfers thus constituted a bottleneck of nutrient transfer on Twin Cays. This is the first comprehensive ecosystem study of nutrient transfers in a mangrove ecosystem, illustrating some mechanisms (e.g. recycling rates, transfer efficiencies) which oligotrophic systems use in order to build up biomass and food webs spanning various trophic levels.

Variable nutrient stoichiometry (carbon:nitrogen:phosphorus) across trophic levels determines community and ecosystem properties in an oligotrophic mangrove system

Science.gov (United States)

Scharler, U.M.; Ulanowicz, Robert E.; Fogel, M.L.; Wooller, M.J.; Jacobson-Meyers, M.E.; Lovelock, C.E.; Feller, I.C.; Frischer, M.; Lee, R.; Mckee, Karen L.; Romero, I.C.; Schmit, J.P.; Shearer, C.

2015-01-01

Our study investigated the carbon:nitrogen:phosphorus (C:N:P) stoichiometry of mangrove island of the Mesoamerican Barrier Reef (Twin Cays, Belize). The C:N:P of abiotic and biotic components of this oligotrophic ecosystem was measured and served to build networks of nutrient flows for three distinct mangrove forest zones (tall seaward fringing forest, inland dwarf forests and a transitional zone). Between forest zones, the stoichiometry of primary producers, heterotrophs and abiotic components did not change significantly, but there was a significant difference in C:N:P, and C, N, and P biomass, between the functional groups mangrove trees, other primary producers, heterotrophs, and abiotic components. C:N:P decreased with increasing trophic level. Nutrient recycling in the food webs was highest for P, and high transfer efficiencies between trophic levels of P and N also indicated an overall shortage of these nutrients when compared to C. Heterotrophs were sometimes, but not always, limited by the same nutrient as the primary producers. Mangrove trees and the primary tree consumers were P limited, whereas the invertebrates consuming leaf litter and detritus were N limited. Most compartments were limited by P or N (not by C), and the relative depletion rate of food sources was fastest for P. P transfers thus constituted a bottleneck of nutrient transfer on Twin Cays. This is the first comprehensive ecosystem study of nutrient transfers in a mangrove ecosystem, illustrating some mechanisms (e.g. recycling rates, transfer efficiencies) which oligotrophic systems use in order to build up biomass and food webs spanning various trophic levels.

Response of anaerobic carbon cycling to water table manipulation in an Alaskan rich fen

Science.gov (United States)

E.S. Kane; M.R. Chivers; M.S. Turetsky; C.C. Treat; D.G. Petersen; M. Waldrop; J.W. Harden; A.D. McGuire

2013-01-01

To test the effects of altered hydrology on organic soil decomposition, we investigated CO2 and CH4 production potential of rich-fen peat (mean surface pH = 6.3) collected from a field water table manipulation experiment including control, raised and lowered water table treatments. Mean anaerobic CO2...

BOREAS TGB-1/TGB-3 CH4 Chamber Flux Data over the NSA Fen

Science.gov (United States)

Bubier, Jill L.; Moore, Tim R.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

The BOREAS TGB-3 team collected methane (CH4) chamber flux measurements at the NSA fen site during May-September 1994 and June-October 1996. Gas samples were extracted approximately every 7 days from chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

Partitioning of habitat effects casts light on the decline of the fen orchid, Liparis loeselii

DEFF Research Database (Denmark)

Andersen, Dagmar Kappel; Ejrnæs, Rasmus; Minter, Martine Olesen

2015-01-01

Liparis loeselii is a rare and declining orchid species restricted to rich fens in the northern hemisphere. Suggested reasons for the decline are habitat destruction, eutrophication, altered hydrology and scrub encroachment after termination of traditional management such as grazing and hay making...

Biodegradación de compuestos fenólicos del alpechín con Aspergillus terreus

Directory of Open Access Journals (Sweden)

García Paeja, María P.

1992-04-01

Full Text Available Olive mill wastewater degradation by Aspergillus terreus and under aerobic conditions at 28°C, was measured by the parameter of phenol content. We have explored the effect of different concentrations of olive mill wastewater upon the activity of Aspergillus terreus. Through HPLC, 10 phenol compounds (90% of the total phenolic content of the olive mill wastewater were identified.Se estudia la degradación de alpechines con Aspergillus terreus en condiciones de aerobiosis y temperatura de 28°C, utilizando como parámetro el contenido fenólico. Se analiza el efecto de la concentración de alpechín con Aspergillus terreus utilizando el mismo parámetro. Se han identificado por cromatografía líquida de alta eficacia (CLAE 10 compuestos fenólicos que suponen el 90% del total del alpechín.

Effects of Reduced and Oxidised Nitrogen on Rich-Fen Mosses: a 4-Year Field Experiment

NARCIS (Netherlands)

Paulissen, Maurice P.C.P.; Bobbink, Roland; Robat, Sandra A.; Verhoeven, Jos T.A.

2016-01-01

Dutch fens, subjected to high nitrogen (N) deposition levels with reduced N (NHy) highly dominating over oxidised N (NOx), have since the second half of the past century seen a significant decline of Scorpidium and other characteristic brown moss species, while several Sphagnum species have

Bartonellosis y fenómeno de Mooser

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Hernando Groot

1941-02-01

Full Text Available Es conocido el fenómeno o reacción de Mooser que este investigador lograra al inocular a un curí por vía intraperitoneal sangre de un tifoso exantemático mejicano, y que consiste en una edema escroto-testicular bastante típico (1-6. En líneas generales se puede decir que un curí inoculado intraperitonealmente con sangre de un tifoso exantemático, presenta después de un período de incubación que varía entre dos días y dos semanas (variación que depende especialmente de las dosis inoculadas uan fiebre de 39,8 a 40,5 que puede durar de 3 a 14 días. Clínicamente la hembra muestra sólo la reacción febril, mientras que en el macho se observan lesiones inflamatorias escroto-testiculares características.

BOREAS TGB-1/TGB-3 NEE Data over the NSA Fen

Science.gov (United States)

Bellisario, Lianne; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Moore, Tim R.

2000-01-01

The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-1) and TGB-3 teams collected several data sets that contributed to understanding the measured trace gas fluxes over sites in the Northern Study Area (NSA). This data set contains Net Ecosystem Exchange of CO2 (NEE) measurements collected with chambers at the NSA fen in 1994 and 1996. Gas samples were extracted approximately every 7 days from chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

Voces actuales en el fenómeno de pasantes de drogas ilícitas en Colombia

Directory of Open Access Journals (Sweden)

Galia J. Benítez

2017-12-01

Full Text Available Este documento se deriva del análisis realizado a las narrativas de los pasantes de drogas ilícitas denominados popularmente como “mulas”; de manera especial, resalta su mirada localizada sobre el fenómeno del tráfico ilegal de drogas en Colombia. El escrito tiene como objetivo: primero, caracterizar la multiplicidad de conceptos que se utilizan para describir este fenómeno y proponer una definición que abarque diferentes acepciones, y segundo, presentar categorías conceptuales que se desprenden de las narrativas de los pasantes de drogas. Como metodología se utilizó el análisis de contenido, para describir, sistematizar y analizar los testimonios voluntarios de 42 personas imputadas y condenadas como pasantes de drogas ilícitas en Colombia. Esta investigación argumenta que uno de los elementos para entender el fenómeno de los pasantes de drogas ilícitas y su experiencia es su condición de vulnerabilidad. Por un lado, los pasantes ocupan un lugar periférico en las organizaciones narcotraficantes; por otro, son altamente vulnerables al sistema socio-técnico establecido por el Estado para prevenir el transporte de drogas ilícitas. Este estudio muestra que las narrativas de los pasantes de drogas se pueden categorizar en cuatro dicotomías, que sirven como elementos retóricos para la ruptura del binario legalidad/ilegalidad.

Evaluation on the Efficiency of Subsurface Drainage in Chiu-Fen Landslide at Northern Taiwan

Science.gov (United States)

Ying, L. Y.; Lin, D. G.

2015-12-01

For administrative district, the Chiu-Fen landslide is situated at northern Taiwan and comes within the jurisdiction of Ruei-Fang district, New Taipei City Government. Chiu-Fen village is a famous spot for sightseeing and tourism in Southeast Asia. In the last decade, for economic purpose, a vast area of slope land in Chiu-Fen area was reclaimed into business and commercial districts. However, due to the complicated geological and hydrological conditions, improper reclamation, and lack of appropriate soil and water conservation facilities, large scale landslides are frequently triggered by typhoon rainfall and causes damages to the transportation and residential building in the community. As a consequence, the government initiated a comprehensive field investigations and remediation plans to stabilize the landslide from 1997 and the remediation works were concentrated on subsurface drainages, namely the application of drainage well (a vertical shaft with multi-level horizontal drainage boreholes). To investigate the efficiency of drainage wells on the landslide, the A1-profile in the landslide which covers the drainage wells W2 and W4 was selected for a series of rainfall seepage and slope stability analyses. In addition, a 48-hrs design rainfall with return period of 25, 50 and 100 years based on the local meteorological data bank was adopted for the analyses. The numerical results indicate the factor safety FS of the three potential sliding surfaces within A1-profile are constantly keeping greater than one (FS > 1.0) and without decreasing with the elapsed time during rainfall. This implies that the subsurface drainage works can drain off the infiltrated rainwater from a high intensity and long duration rainfall and preserve the slope stability of landslides from deterioration. Finally, the efficiency of the drainage wells can be evaluated quantitatively in terms of the time-dependent factor of safety and the pore water pressure distribution on several potential

Research of Ancient Architectures in Jin-Fen Area Based on GIS and BIM Technology

International Nuclear Information System (INIS)

Jia, Jing; Zheng, Qiuhong; Gao, Huiying; Sun, Hai

2017-01-01

The number of well-preserved ancient buildings located in Shanxi Province, enjoying the absolute maximum proportion of ancient architectures in China, is about 18418, among which, 9053 buildings have the structural style of wood frame. The value of the application of BIM (Building Information Modeling) and GIS (Geographic Information System) is gradually probed and testified in the corresponding fields of ancient architecture’s spatial distribution information management, routine maintenance and special conservation and restoration, the evaluation and simulation of related disasters, such as earthquake. The research objects are ancient architectures in JIN-FEN area, which were first investigated by Sicheng LIANG and recorded in his work of “Chinese ancient architectures survey report”. The research objects, i.e. the ancient architectures in Jin-Fen area include those in Sicheng LIANG’s investigation, and further adjustments were made through authors’ on-site investigation and literature searching and collection. During this research process, the spatial distributing Geodatabase of research objects is established utilizing GIS. The BIM components library for ancient buildings is formed combining on-site investigation data and precedent classic works, such as “Yingzao Fashi”, a treatise on architectural methods in Song Dynasty, “Yongle Encyclopedia” and “Gongcheng Zuofa Zeli”, case collections of engineering practice, by the Ministry of Construction of Qing Dynasty. A building of Guangsheng temple in Hongtong county is selected as an example to elaborate the BIM model construction process based on the BIM components library for ancient buildings. Based on the foregoing work results of spatial distribution data, attribute data of features, 3D graphic information and parametric building information model, the information management system for ancient architectures in Jin-Fen Area, utilizing GIS and BIM technology, could be constructed to support

Avaliação da influência de substâncias fenólicas e carotenoides na anomalia do epicarpo da goiaba, "anelamento"

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Taiji Watanabe

2011-03-01

Full Text Available A anomalia do epicarpo da goiaba, comumente relatada por agricultores e técnicos como o "anelamento juvenil da goiaba", tem causado preocupação devido à desinformação sobre o assunto. O objetivo deste estudo foi analisar quimicamente as concentrações de substâncias fenólicas e carotenoides na região do epicarpo de goiabas afetadas pelo "anelamento", visando a caracterizar essa anomalia previamente relatada. Foram analisadas substâncias fenólicas (taninos, flavonas/flavonóis, antocianinas e fenóis totais e carotenoides em epicarpos de frutos verdes e maduros de goiabeiras cv. Paluma, com e sem anomalia. O delineamento experimental adotado foi o inteiramente casualizado, sendo estabelecidos seis tratamentos com o epicarpo dos frutos maduro sem anomalia na região inferior (FMSI; frutos maduros sem injuria na região superior (FMSS; frutos verdes sem anomalia na região inferior (FVSI; frutos verdes sem anomalia na região superior (FVSS; frutos verdes com anomalia na região inferior (FVCI; frutos verdes com anomalia na região superior (FVCS. Dentre as substâncias analisadas, os carotenoides, os taninos e os fenóis totais mostram indicativos para a caracterização do anelamento. Tanto substâncias fenólicas quanto carotenoides apresentam propriedades antioxidantes e, dessa forma, poderiam estar relacionadas à defesa antioxidante causada por um fator de estresse ainda desconhecido, que promove o "anelamento" característico apresentado pelas goiabas.

Assessing the Roles of Iron, Macronutrients and Wet deposition in Controlling Phytoplankton Growth in Seasonally Oligotrophic Waters of the Mid-Atlantic Bight

Science.gov (United States)

Sedwick, P.; Mulholland, M. R.; Najjar, R.; Bernhardt, P. W.; Price, L. M.; Sohst, B. M.; Sookhdeo, C.; Widner, B.

2016-02-01

The role of iron supply in regulating phytoplankton production in high-nutrient, low-chlorophyll ocean regions has been well established. Less clear, however, is the importance of iron for phytoplankton processes in other oceanic settings, such as coastal and oligotrophic waters, where differential changes in the supply and removal of dissolved iron (dFe) can result in limitation or co-limitation of growth due to iron deficiency. One such region of interest is the Mid-Atlantic Bight (MAB), where previous field experiments have provided some evidence of co-limitation of algal growth by nitrogen and iron. In summer 2014 we conducted field sampling and shipboard experiments to assess the role of iron and macronutrient availability in controlling primary production in seasonally oligotrophic waters over the MAB continental slope, with a focus on the the impacts of wet deposition. Our results indicate that nitrogen was the proximate limiting nutrient, with a secondary limitation imposed by availability of phosphorus; we found no evidence for a deficiency in dFe, which was present at concentrations in the range 0.3-0.9 nM. Phytoplankton growth was clearly stimulated by the addition of natural rainwater, suggesting that summer rain events stimulate primary production in the MAB by contributing new nitrogen (primarily as ammonium) and phosphorus, whilst maintaining iron-replete conditions.

Polyextremotolerant black fungi: oligotrophism, adaptive potential and a link to lichen symbioses

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Cene eGostinčar

2012-11-01

Full Text Available Black meristematic fungi can survive high doses of radiation and are resistant to desiccation. These adaptations help them to colonize harsh oligotrophic habitats, e.g. on the surface and subsurface of rocks. One of their most characteristic stress-resistance mechanisms is the accumulation of melanin in the cell walls. This, production of other protective molecules and a plastic morphology further contribute to ecological flexibility of black fungi. Increased growth rates of some species after exposure to ionizing radiation even suggest yet unknown mechanisms of energy production. Other unusual metabolic strategies may include harvesting UV or visible light or gaining energy by forming facultative lichen-like associations with algae or cyanobacteria. The latter is not entirely surprising, since certain black fungal lineages are phylogenetically related to clades of lichen-forming fungi. Similar to black fungi, lichen-forming fungi are adapted to growth on exposed surfaces with low availability of nutrients. They also efficiently use protective molecules to tolerate frequent periods of extreme stress. Traits shared by both groups of fungi may have been important in facilitating the evolution and radiation of lichen-symbioses.

Can Asian Dust Trigger Phytoplankton Blooms in the Oligotrophic Northern South China Sea?

Science.gov (United States)

Wang, Sheng Hsiang; Hsu, Nai-Yung Christina; Tsay, Si-Chee; Lin, Neng-Huei; Sayer, Andrew M.; Huang, Shih-Jen; Lau, William K. M.

2012-01-01

Satellite data estimate a high dust deposition flux (approximately 18 g m(exp-2 a(exp-1) into the northern South China Sea (SCS). However, observational evidence concerning any biological response to dust fertilization is sparse. In this study, we combined long-term aerosol and chlorophyll-a (Chl-a) measurements from satellite sensors (MODIS and SeaWiFS) with a 16-year record of dust events from surface PM10 observations to investigate dust transport, flux, and the changes in Chl-a concentration over the northern SCS. Our result revealed that readily identifiable strong dust events over this region, although relatively rare (6 cases since 1994) and accounting for only a small proportion of the total dust deposition (approximately 0.28 g m(exp-2 a(exp-1), do occur and could significantly enhance phytoplankton blooms. Following such events, the Chl-a concentration increased up to 4-fold, and generally doubled the springtime background value (0.15 mg m(exp-3). We suggest these heavy dust events contain readily bioavailable iron and enhance the phytoplankton growth in the oligotrophic northern SCS.

Conteúdo de fenólicos, flavonoides totais e atividade antioxidante de amostras de própolis comerciais

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Elizângela Alves

2013-01-01

Full Text Available Neste trabalho foram determinadas algumas características físico-químicas de própolis de Santa Maria- RS. Foram analisadas seis amostras comerciais obtidas em farmácias e lojas de produtos naturais na cidade citada. A composição química, quanto aos fenólicos e flavonoides totais, assim como a atividade antioxidante, foi testada e comparada. A alta atividade antioxidante dos extratos puros (ou diluídos foi explicada pelo teor dos flavonoides e fenólicos totais, confirmando a relação desses compostos na ação preventiva contra radicais livres. As seis amostras comerciais analisadas possuíram de fenólicos 70,60 mg a 539,10 mg (expresso em mg de ácido gálico/g de extrato de própolis e de flavonoides 48,95 mg a 114,50 mg (expresso em mg de quercetina/g de extrato de própolis. A atividade antioxidante maior foi do extrato aquoso, tanto pela inibição do radical DPPH quanto pela atividade quelante. No extrato aquoso de própolis obteve-se resultados satisfatórios para uma futura aplicação em alimento.

El Frente Estudiantil Nacional (FEN: juventud y estudiantado en el proceso contestatario de los años sesenta en Argentina

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Alejandra Reta

2009-12-01

Full Text Available Este artículo forma parte de un proyecto más amplio que aborda el proceso de acercamiento al Peronismo por parte de un sector del movimiento estudiantil en Argentina durante los años sesentas, tomando el caso particular del Frente Estudiantil Nacional (FEN. El FEN fue una organización universitaria “de pasaje al peronismo”, que buscaba inserción “legítima” en el mismo, vinculándose a sectores del peronismo histórico y al trabajo barrial.Proponemos privilegiar el análisis de documentos, aunque incluimos también algunos testimonios que nos sirven de apoyo. A partir de allí pretendemos explorar algunos “componentes contestatarios”, ligados al clima de ideas de la época, y visualizar cómo este actor colectivo se posiciona dentro de las categorías de “juventud” y del “estudiantado”, que aparecen en el discurso, considerando que el FEN reivindicó constantemente su carácter de tendencia estudiantil universitaria y su militancia juvenil.

Turismo religioso: fenómeno social y económico

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Sandra Maribel Tobón Perilla

2013-12-01

Full Text Available El turismo religioso, como fenómeno social y económico, ha cobrado interés entre académicos y empresarios por las dinámicas que ha generado en las comunidades receptoras de visitantes. Para los primeros, el interés radica en el estudio de las motivaciones, intereses y necesidades espirituales o culturales que parecen haber despertado los centros religiosos; para los segundos, el impacto económico y las oportunidades de rentas adicionales que generan los visitantes, creando nuevas oportunidades de negocios y fuentes de ingresos y empleo para las comunidades aledañas. Este documento hace una revisión a la bibliografía sobre el tema de turismo religioso en el mundo, para lo cual se consultaron las bases de datos ScienceDirect, Jstor, Ebsco, ProQuest y Google Académico, a fin de rastrear las publicaciones más relevantes y estudios empíricos sobre el tema, haciendo un recorrido desde 1963 hasta 2013. Se concluye que el turismo religioso es un fenómeno que tiene su antecedente en el peregrinaje a centros religiosos, pero donde además de las motivaciones, netamente religiosas –ofrecer un sacrificio, obtener un beneficio divino o expiar pecados–, existe un interés cultural, en términos de conocer centros históricos o profundizar sobre las raíces de un credo religioso. Adicionalmente, se observa cómo el turismo religioso se ha convertido en un motor de desarrollo económico de las ciudades receptoras de viajeros a sitios religioso.

A Novel Roseosiphophage Isolated from the Oligotrophic South China Sea

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Yunlan Yang

2017-05-01

Full Text Available The Roseobacter clade is abundant and widespread in marine environments and plays an important role in oceanic biogeochemical cycling. In this present study, a lytic siphophage (labeled vB_DshS-R5C infecting the strain type of Dinoroseobacter shibae named DFL12T, which is part of the Roseobacter clade, was isolated from the oligotrophic South China Sea. Phage R5C showed a narrow host range, short latent period and low burst size. The genome length of phage R5C was 77, 874 bp with a G+C content of 61.5%. Genomic comparisons detected no genome matches in the GenBank database and phylogenetic analysis based on DNA polymerase I revealed phylogenetic features that were distinct to other phages, suggesting the novelty of R5C. Several auxiliary metabolic genes (e.g., phoH gene, heat shock protein and queuosine biosynthesis genes were identified in the R5C genome that may be beneficial to the host and/or offer a competitive advantage for the phage. Among siphophages infecting the Roseobacter clade (roseosiphophages, four gene transfer agent-like genes were commonly located with close proximity to structural genes, suggesting that their function may be related to the tail of siphoviruses. The isolation and characterization of R5C demonstrated the high genomic and physiological diversity of roseophages as well as improved our understanding of host–phage interactions and the ecology of the marine Roseobacter.

Pressões (sócio)linguísticas na determinação do acento enfático: análise de alguns fenômenos variáveis

OpenAIRE

Carlos Alexandre Gonçalves

2017-01-01

Analise do fenômeno da ênfase prosódica, tomando como base seu efeito em fenômenos de variação/mudança linguística. Descrição da ênfase como grupo de fator relevante em pesquisas labovianas sobre processo de assimilação -ndo/-no. os fenômenos de aférese e prótese em processos de intensificação da língua.

Prospects of fen restoration in relation to changing land use—An example from central Poland

NARCIS (Netherlands)

Klimkowska, A.; Dzierza, P.; Grootjans, A.P.; Kotowski, W.; Diggelen, R.

2010-01-01

We carried out an eco-hydrological analysis to evaluate the most important effects of land use changes on the hydrological functioning of a fen system in Poland. We measured water levels (hydraulic heads) and water flow along a transect through the study area and also analysed land use changes using

Prospects of fen restoration in relation to changing land use-An example from central Poland

NARCIS (Netherlands)

Klimkowska, Agata; Dzierża, Paulina; Grootjans, Ab P.; Kotowski, Wiktor; Diggelen, Rudy Van

2010-01-01

We carried out an eco-hydrological analysis to evaluate the most important effects of land use changes on the hydrological functioning of a fen system in Poland. We measured water levels (hydraulic heads) and water flow along a transect through the study area and also analysed land use changes using

Atividade antioxidante e teor de fenólicos em couve-manteiga (brassica oleracea l. var. acephala submetida a diferentes sistemas de cultivo e métodos de preparo

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Geysa Duarte Junger Rigueira

2017-01-01

Full Text Available O estudo avaliou a influência de sistemas de cultivo e de métodos de preparo na atividade antioxidante e no teor de fenólicos de folhas e talos da couve manteiga (Brassica Oleracea L. var. acephala. Amostras de couve cultivadas pelo sistema convencional e orgânico foram pesadas, higienizadas e os talos separados das folhas. Foram submetidas aos modos de preparo: cru (couve in natura; calor seco (refogada e calor úmido (imersa em água fervente. Avaliou-se à atividade antioxidante e os compostos fenólicos pelo método espectrofotométrico. A verificação de compostos fenólicos e compostos com atividade antioxidante foi realizada por Cromatografia em Camada Delgada (CCD. O sistema de cultivo orgânico e o preparo em calor seco foram os tratamentos que obtiveram os maiores percentuais de antioxidantes e teores de compostos fenólicos, principalmente, em folhas de couve.  A atividade antioxidante variou de 38 a 87% nas folhas e de 13 a 56% nos talos de couve. Quanto aos compostos fenólicos os teores médios estiveram entre 173 e 244 mg EAG/100g nas folhas e 86 e 180 mg EAG/100g nos talos. As análises por CCD revelaram que todos os extratos de folhas e talos de couve apresentaram compostos fenólicos bem como componentes com ação antioxidante, mas nem todos com correlação. Conclui-se que a combinação de sistema de cultivo orgânico e cocção em calor seco pode ser eficiente para preservação e ou aumento do teor de compostos fenólicos e da atividade antioxidante em talos e, principalmente, em folhas de couve.

Net community production and metabolic balance at the oligotrophic ocean site, station ALOHA

Science.gov (United States)

le B. Williams, Peter J.; Morris, Paul J.; Karl, David M.

2004-11-01

To test the hypothesis that in oligotrophic areas of the ocean respiration exceeds production, a 12-month study was undertaken of in vitro-determined net oxygen production and consumption in the top 150 m of the water column at the extreme oligotrophic site, Station ALOHA, in the North Pacific subtropical gyre. Throughout the year the water column was observed to be in metabolic deficit, the calculated cumulative shortfall being 9±1.7 mol O2 m-2 a-1 (approximately 100 g C m-2 a-1), an amount equivalent to 40% of measured production (annual estimated rates of production and consumption were, respectively, 22 and 31 mol O2 m-2 a-1). We consider three possible explanations for the observed deficit: the in vitro oxygen rate measurements, in themselves, are fundamentally flawed and should be discounted, the observations are correct and the observed deficit is a true account of the balance of oxygen (and organic carbon) at Station ALOHA, or the observations are correct as they stand, but need not be interpreted as organic carbon imbalance for that ecosystem. We find no error unique to the oxygen rate measurements themselves. We find also no evidence that the associated organic carbon deficit can be sustained over the long-term by internal organic reserves or by external subsidy. Accordingly we accept the geochemical findings that calculated in situ oxygen flux requires the euphotic zone of the water column at this site to be slightly (circa 2 mol C m-2 a-1) autotrophic, in contrast to the simple analysis of our observations which gives a net heterotrophic water column. We discuss a number of processes that may give rise to the observed discrepancy. In part it may derive from the difficulty of reproducing the variations in the light field experienced by an algal cell due to vertical advection. It may also derive from the intermittency of production. This latter effect would manifest itself in the following manner. Because of its universal distribution in the food web

Análisis de los fenómenos meteorológicos que provocaron penetraciones del mar en el Malecón habanero.

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Lázara Díaz Maqueira

2003-03-01

Full Text Available Se presenta la caracterización de algunos de los fenómenos meteorológicos peligrosos que produjeron penetraciones del mar en el Malecón habanero y su tipificación sinóptica, con el objetivo de que se utilice como herramienta de trabajo para predecir con suficiente antelación este fenómeno y de esta forma disminuir las consecuencias del mismo en el área urbana aledaña. También se realiza una descripción del Malecón habanero por tramos y los factores que producen las inundaciones costeras por penetraciones del mar. La comprensión de las interacciones entre las características constructivas del Malecón y los factores desencadenantes de las inundaciones han ayudado a predecir la magnitud del fenómeno y alertar convenientemente a las organizaciones estatales e intereses costeros para que tomen las medidas requeridas en cada caso.

Relación entre el fenómeno de la ilusión de la mano falsa y variables personales

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Gina Rodríguez-Melgarejo

2015-07-01

Full Text Available El fenómeno de la ilusión de la mano falsa (IMF se ha propuesto como un diseño que permite discriminar procesos perceptuales a partir de entradas sensoriales multimodales. Se han reportado varias modificaciones y variables que podrían afectar la generación del fenómeno. Este estudio se planteó bajo un diseño descriptivo-correlacional del fenómeno. Se realizó el procedimiento en jóvenes (16-48 años M = 20.86 años, DE = 4.4 colombianos para replicar el fenómeno de IMF. Los sujetos se dividieron al azar en dos grupos que diferían en el tipo de estimulación (sincrónica y desincronizada. La identificación de la IMF se realizó mediante la escala reportada en múltiples estudios, mostrando que en algunas variables como la estimulación se presentaba una diferencia en el reporte de IMF (P2. χ2 = 5.856: p < 0.05; P3. χ2 = 6.655: p < 0.01 y P7 (χ2 = 4.764: p < 0.05. Otras variables como sexo y dominancia manual mostraron algunas diferencias. La escala presenta una consistencia interna aceptable (α = 0.8. Los resultados de la IMF son similares a algunos estudios pero con puntuaciones menores que en los estudios iniciales, la diferencia en cuanto al género en tareas perceptuales podría explicar gran parte de los resultados.

Passive films and corrosion protection due to phosphonic acid inhibitors

Energy Technology Data Exchange (ETDEWEB)

Fang, J.L.; Liu, Q. (Nanjing Univ. (China)); Li, Y.; Wang, Z.W. (Nanjing Inst. of Chemical Tech. (China))

1993-04-01

For protecting mild steel from corrosion, aminotrimethylidenephosphonic acid (ATMP) was more effective than 1-hydroxyethylidene diphosphonic acid (HEDP), N.N-dimethylidenediphosphonic acid (EEDP), and ethylenediaminetetramethylidenephosphonic acid (EDTMP). A 20-min treatment in 1.0 mol/l of ATMP with a pH 0.23 at 45 C formed an anti-corrosive complex film that was composed of 48.4% O, 28.6% P, 7.0% Fe, 4.3% N, and 11.7% C, based on x-ray photoelectron spectroscopy and Auger electron spectroscopy. From differences in binding energies of Fe, N, and O, in the shift of C-N and P-O vibration, in the reflection FTIR spectra, and in the change of P-OH and Fe-N vibration before and after film formation, it was deduced that N and O in ATMP were coordinated with Fe[sub 2+] in the film.

BOREAS TGB-3 Plant Species Composition Data over the NSA Fen

Science.gov (United States)

Bubier, Jill L.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-3) team collected several data sets that contributed to understanding the measured trace gas fluxes over sites in the Northern Study Area (NSA). This data set contains information about the composition of plant species that were within the collars used to measure Net Ecosystem Exchange of CO2 (NEE). The species composition was identified to understand the differences in NEE among the various plant communities in the NSA fen. The data were collected in July of 1994 and 1996. The data are contained in comma-delimited, ASCII files.

Cyberbullying: percepções acerca do fenômeno e das estratégias de enfrentamento

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Sidclay Bezerra Souza

2014-01-01

Full Text Available O cyberbullying, caracterizado como um dos tipos de violência em contexto educativo, apresenta-se como uma das principais causas do mal-estar vivido por seus protagonistas. O estudo inserido no Projeto Cyberbullying - o diagnóstico da situação em Portugal pretendeu compreender o fenômeno a partir das vivências de 118 estudantes do primeiro ano do Ensino Superior público português, que responderam a um questionário. Pudemos perceber a percepção dos alunos sobre o fenômeno e a importância que pares, professores e pais apresentam no enfrentamento e prevenção do cyberbullying. Tais resultados orientam-se no sentido do desenvolvimento sistêmico de comunidades que se fortalecem internamente para que cada um se sinta autorizado a intervir e a cuidar dos que nelas são vítimas de violência.

Constraining the sources and cycling of dissolved organic carbon in a large oligotrophic lake using radiocarbon analyses

Science.gov (United States)

Zigah, Prosper K.; Minor, Elizabeth C.; McNichol, Ann P.; Xu, Li; Werne, Josef P.

2017-07-01

We measured the concentrations and isotopic compositions of solid phase extracted (SPE) dissolved organic carbon (DOC) and high molecular weight (HMW) DOC and their constituent organic components in order to better constrain the sources and cycling of DOC in a large oligotrophic lacustrine system (Lake Superior, North America). SPE DOC constituted a significant proportion (41-71%) of the lake DOC relative to HMW DOC (10-13%). Substantial contribution of 14C-depleted components to both SPE DOC (Δ14C = 25-43‰) and HMW DOC (Δ14C = 22-32‰) was evident during spring mixing, and depressed their radiocarbon values relative to the lake dissolved inorganic carbon (DIC; Δ14C ∼ 59‰). There was preferential removal of 14C-depleted (older) and thermally recalcitrant components from HMW DOC and SPE DOC in the summer. Contemporary photoautotrophic addition to HMW DOC was observed during summer stratification in contrast to SPE DOC, which decreased in concentration during stratification. Serial thermal oxidation radiocarbon analysis revealed a diversity of sources (both contemporary and older) within the SPE DOC, and also showed distinct components within the HMW DOC. The thermally labile components of HMW DOC were 14C-enriched and are attributed to heteropolysaccharides (HPS), peptides/amide and amino sugars (AMS) relative to the thermally recalcitrant components reflecting the presence of older material, perhaps carboxylic-rich alicyclic molecules (CRAM). The solvent extractable lipid-like fraction of HMW DOC was very 14C-depleted (as old as 1270-2320 14C years) relative to the carbohydrate-like and protein-like substances isolated by acid hydrolysis of HMW DOC. Our data constrain relative influences of contemporary DOC and old DOC, and DOC cycling in a modern freshwater ecosystem.

Tolerância ao fenômeno alucinatório induzido pelo zolpidem: relato de caso Tolerancia al fenómeno alucinatorio inducido por el zolpidem: relato de caso Tolerance to zolpidem-induced hallucinations: case report

Directory of Open Access Journals (Sweden)

Saint-Clair Bahls

2005-12-01

Full Text Available INTRODUÇÃO: O hipnótico zolpidem é considerado efetivo e seguro, entretanto, existem na literatura alguns relatos de caso de fenômeno alucinatório associado ao seu uso. Relataremos mais um caso de alucinações induzidas pelo zolpidem em paciente jovem do sexo feminino. DISCUSSÃO: Este caso, segundo nosso conhecimento, é o primeiro descrito na literatura que sugere a possibilidade de ocorrer, em alguns pacientes, o desenvolvimento de tolerância a esse efeito alucinatório adverso raro, porém, importante. Apresentamos uma discussão sobre algumas hipóteses farmacocinéticas e farmacodinâmicas deste fenômeno. CONCLUSÕES: Alertamos para a necessidade de atenção ao fato da indução alucinatória pelo zolpidem e sua tolerância, assim como a importância de seu melhor entendimento.INTRODUCTION: El hipnótico zolpidem es considerado efectivo y seguro. Sin embargo, hay en la literatura algunos relatos de caso de fenómeno alucinatorio asociado a su uso. Relataremos un caso más sobre alucinaciones inducidas por zolpidem en una paciente joven de sexo femenino. DISCUSIÓN: Este caso, según nuestro conocimiento, es el primero descrito en la literatura que sugiere la posibilidad de que en algunos pacientes ocurra el desarrollo de tolerancia a este efecto alucinatorio, adverso y raro, sin embargo, importante. Presentamos una discusión sobre algunas hipótesis farmacocinéticas y farmacodinámicas de este fenómeno. CONCLUSION: Por la necesidad de atención, alertamos al hecho de la inducción alucinatoria relacionada al zolpidem y a su tolerancia, así como a la importancia de comprenderla mejor.BACKGROUND: Zolpidem is reported to be a safe and effective hypnotic agent. In the literature, there are some case reports of hallucinations after zolpidem administration. We report one more case in witch zolpidem lead to hallucinations in young adult female. DISCUSSION: This case, to our knowledge, is the first to suggest the possibility of

Influence of ocean acidification and deep water upwelling on oligotrophic plankton communities in the subtropical North Atlantic

DEFF Research Database (Denmark)

Taucher, Jan; Bach, Lennart T.; Boxhammer, Tim

2017-01-01

Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. Increasing evidence indicates that these changes-summarized by the term ocean acidification (OA)-can significantly affect marine food webs and biogeochemical...... cycles. However, current scientific knowledge is largely based on laboratory experiments with single species and artificial boundary conditions, whereas studies of natural plankton communities are still relatively rare. Moreover, the few existing community-level studies were mostly conducted in rather...... and successfully simulated a deep water upwelling event that induced a pronounced plankton bloom. Our study revealed significant effects of OA on the entire food web, leading to a restructuring of plankton communities that emerged during the oligotrophic phase, and was further amplified during the bloom...

Hydrometeorological conditions preceding wildfire, and the subsequent burning of a fen watershed in Fort McMurray, Alberta, Canada

Science.gov (United States)

Elmes, Matthew C.; Thompson, Dan K.; Sherwood, James H.; Price, Jonathan S.

2018-01-01

The destructive nature of the ˜ 590 000 ha Horse river wildfire in the Western Boreal Plain (WBP), northern Alberta, in May of 2016 motivated the investigation of the hydrometeorological conditions that preceded the fire. Historical climate and field hydrometeorological data from a moderate-rich fen watershed were used to (a) identify whether the spring 2016 conditions were outside the range of natural variability for WBP climate cycles, (b) explain the observed patterns in burn severity across the watershed, and (c) identify whether fall and winter moisture signals observed in peatlands and lowland forests in the region are indicative of wildfire. Field hydrometeorological data from the fen watershed confirmed the presence of cumulative moisture deficits prior to the fire. Hydrogeological investigations highlighted the susceptibility of fen and upland areas to water table and soil moisture decline over rain-free periods (including winter), due to the watershed's reliance on supply from localized flow systems originating in topographic highs. Subtle changes in topographic position led to large changes in groundwater connectivity, leading to greater organic soil consumption by fire in wetland margins and at high elevations. The 2016 spring moisture conditions measured prior to the ignition of the fen watershed were not illustrated well by the Drought Code (DC) when standard overwintering procedures were applied. However, close agreement was found when default assumptions were replaced with measured duff soil moisture recharge and incorporated into the overwintering DC procedure. We conclude that accumulated moisture deficits dating back to the summer of 2015 led to the dry conditions that preceded the fire. The infrequent coinciding of several hydrometeorological conditions, including low autumn soil moisture, a modest snowpack, lack of spring precipitation, and high spring air temperatures and winds, ultimately led to the Horse river wildfire spreading widely and

Enhancing surface methane fluxes from an oligotrophic lake: exploring the microbubble hypothesis.

Science.gov (United States)

McGinnis, Daniel F; Kirillin, Georgiy; Tang, Kam W; Flury, Sabine; Bodmer, Pascal; Engelhardt, Christof; Casper, Peter; Grossart, Hans-Peter

2015-01-20

Exchange of the greenhouse gases carbon dioxide (CO2) and methane (CH4) across inland water surfaces is an important component of the terrestrial carbon (C) balance. We investigated the fluxes of these two gases across the surface of oligotrophic Lake Stechlin using a floating chamber approach. The normalized gas transfer rate for CH4 (k600,CH4) was on average 2.5 times higher than that for CO2 (k600,CO2) and consequently higher than Fickian transport. Because of its low solubility relative to CO2, the enhanced CH4 flux is possibly explained by the presence of microbubbles in the lake’s surface layer. These microbubbles may originate from atmospheric bubble entrainment or gas supersaturation (i.e., O2) or both. Irrespective of the source, we determined that an average of 145 L m(–2) d(–1) of gas is required to exit the surface layer via microbubbles to produce the observed elevated k600,CH4. As k600 values are used to estimate CH4 pathways in aquatic systems, the presence of microbubbles could alter the resulting CH4 and perhaps C balances. These microbubbles will also affect the surface fluxes of other sparingly soluble gases in inland waters, including O2 and N2.

Phase Transformations and Phase Equilibria in the Fe-N System at Temperatures below 573 K

DEFF Research Database (Denmark)

Malinov, S.; Böttger, A.J.; Mittemeijer, E.J.

2001-01-01

The phase transformations of homogeneous Fe-N alloys of nitrogen contents from 10 to 26 at. pct were investigated by means of X-ray diffraction analysis upon aging in the temperature range from 373 to 473 K. It was found that precipitation of alpha double prime-Fe16N2 below 443 K does not only oc...

Do uric acid deposits in zooxanthellae function as eye-spots?

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Hiroshi Yamashita

2009-07-01

Full Text Available The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

Do uric acid deposits in zooxanthellae function as eye-spots?

Science.gov (United States)

Yamashita, Hiroshi; Kobiyama, Atsushi; Koike, Kazuhiko

2009-07-17

The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium) and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

La definición jurídica del fenómeno metropolitano en el ámbito subnacional mexicano

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Alberto Arellano Ríos

2014-10-01

Full Text Available En este texto se analiza la definición jurídica del fenómeno metropolitano en seis Estados de la república mexicana. Se estudian seis legislaciones estatales creadas expresamente para atender y darle forma jurídica a un problema que se ha acentuado con mayor fuerza en México, el cual desde el punto de vista de las instancias gubernamentales tiene mayor relevancia en los últimos veinte años. De este modo, el documento esboza el fenómeno metropolitano como contexto social. Luego traza los mecanismos constitucionales contemplados para gestionar y gobernar las zonas metropolitanos para, finalmente, exponer los casos estatales que ante la ausencia de un marco legal nacional, y desde la lógica del sistema federal, intentan sentar bases jurídicas para resolver este problema.

Photochemical production of ammonium in the oligotrophic Cyprus Gyre (Eastern Mediterranean

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V. Kitidis

2006-01-01

Full Text Available We investigated the photoproduction of ammonium (NH4+ in surface waters of the Cyprus gyre in the central Eastern Mediterranean in May 2002, in 8 on deck irradiations with freshly collected, filtered samples. NH4+ photoproduction (photoammonification increased with time-integrated irradiance during the course of irradiations. Photoammonification rates around local noon were 0.4–2.9 nmol L−1 h−1. Normalised to time integrated irradiance, these rates were 0.9–3.8 pmol L−1 h−1/(W m−2 and were significantly correlated with Chromophoric Dissolved Organic Matter (CDOM absorbance at 300 nm normalised to Dissolved Organic Carbon (DOC. These results are consistent with the notion that successive CDOM photobleaching in the surface mixed layer results in decreased DOC-normalised light absorbance concurrent with decreased dissolved organic matter reactivity with regard to photochemical NH4+ release. Combining our experimental data with estimates of annual solar irradiance and water column light attenuation yields an annual photoammonification rate for the Cyprus Gyre of 40±17 mmol m−2 a−1, equivalent to ~12±5% of the previously estimated annual nitrogen requirement of new production and in the same order of magnitude as atmospheric N deposition in this region. Based on this analysis, NH4+ photoproduction makes a small, but significant contribution to the nitrogen budget of the euphotic zone in the oligotrophic Cyprus Gyre.

Primary marine aerosol emissions from the Mediterranean Sea during pre-bloom and oligotrophic conditions: correlations to seawater chlorophyll a from a mesocosm study

OpenAIRE

Schwier , A. N.; Rose , C.; Asmi , E.; Ebling , A. M.; Landing , W. M.; Marro , S.; Pedrotti , M.-L.; Sallon , A.; Iuculano , F.; Agusti , S.; Tsiola , A.; Pitta , P.; Louis , J.; Guieu , C.; Gazeau , F.

2015-01-01

The effect of ocean acidification and changing water conditions on primary (and secondary) marine aerosol emissions is not well understood on a regional or a global scale. To investigate this effect as well as the indirect effect on aerosol that changing biogeochemical parameters can have, ~ 52 m3 pelagic mesocosms were deployed for several weeks in the Mediterranean Sea during both winter pre-bloom and summer oligotrophic conditions and were subjected to various levels of C...

Effectiveness of turf stripping as a measure for restoring species-rich fen meadows in suboptimal hydrological conditions

NARCIS (Netherlands)

Hoek, van der D.; Heijmans, M.M.P.D.

2007-01-01

Most species-rich fen meadows in nature reserves in The Netherlands are acidified due to weaker upwelling of base-rich groundwater. The present study investigated whether and why turf stripping combined with superficial drainage might promote the long-term recovery of such meadows and restore the

Geochemical response of a calcareous fen to road salt contamination during snow melt and precipitation events: Kampoosa Bog, Stockbridge, MA

Science.gov (United States)

Rhodes, A. L.; Guswa, A. J.

2008-12-01

Kampoosa Bog is the largest and most diverse calcareous lake-basin fen remaining in Massachusetts, and it is one of the state's elite Areas of Critical Environmental Concern (ACEC). The ground water chemistry of the fen has been greatly altered by road salt runoff (NaCl) from the Massachusetts Turnpike, which crosses the northern margin of the wetland complex. Ground water samples collected at different depths within the wetland, measurements of exchangeable Na from an eight-meter core, and hydraulic conductivity measurements suggest that ground water flow and contamination is largely a near- surface phenomenon. Detailed sampling of surface and ground waters during three spring snow melt events and one precipitation event characterizes the geochemical response of the wetland to hydrologic events. Overall, Na:Cl ratios for surface and ground water samples are less than one, and sodium and chloride imbalances suggest that 20-30% of sodium from rock salt is stored on cation exchange sites on organic material. Na:Cl ratios greater than one for fen ground water sampled during Snow Melt 2007 suggest that sodium can be released from cation exchange sites back to ground water under dilute conditions. The total mass of Na and Cl exported from the wetland is greatest under conditions of high discharge. The flux of dissolved salts at the outlet of the fen during Snow Melt 2005 accounts for ~ 24% Na and ~ 32% Cl of rock salt added to the Massachusetts Turnpike during 2004-2005. Estimates of annual fluxes of Na and Cl are on par with the amount of road salt applied, and sodium and chloride concentrations in shallow groundwater have decreased since 2002. The months of March, April and May are the primary months for salt export, accounting for more than half of the annual salt flux in 2005. Concerning the annual net export of sodium and chloride, large rain events may be more important with removing dissolved salts from the fen than snow melt because snow melt also is a time when

De columbine à virgínia tech: reflexões com base empírica sobre um fenômeno em expansão

OpenAIRE

Vieira,Timoteo Madaleno; Mendes,Francisco Dyonísio Cardoso; Guimarães,Leonardo Conceição

2009-01-01

O fenômeno conhecido como school shooting vem chamando a atenção do mundo, principalmente após a tragédia na Columbine High School, na cidade de Littleton, Colorado, nos Estados Unidos, em 1999. Posteriormente, em abril de 2007, o estudante Cho Seung-Hui protagonizou um massacre de proporções ainda maiores ao atirar contra estudantes do Virginia Polytechnic Institute and State University, matando 32 pessoas e se suicidando ao final. O presente artigo reflete sobre o fenômeno chamando a atençã...

FEN LABORATUARLARININ İŞLEVSELLİĞİNİN İLKÖĞRETİM OKULLARINDA DEĞERLENDİRİLMESİ

OpenAIRE

YILAYAZ, Ömer; TURAN, Mehmet; BAHŞİ, Muammer

2009-01-01

Bu araştırmada, ilköğretim okullarındaki fen laboratuarlarının işlevselliğine ilişkin öğrenci görüşlerinin belirlemesi amaçlanmıştır. Bu amaçla 19 maddelik bir anket formu hazırlanmıştır. Çalışma, Fırat Üniversitesi Eğitim Fakültesi Fen ve Teknoloji öğretmenliği bölümünde öğrenim gören 76 öğrenciye (4. sınıf) uygulanmıştır. Anket sonucunda elde edilen veriler, SPSS paket istatistik programında değerlendirilmiştir.

Fenóis totais, atividade antioxidante e constituintes químicos de extratos de Anacardium occidentale L., Anacardiaceae

Directory of Open Access Journals (Sweden)

Mariana H. Chaves

Full Text Available O presente artigo relata o isolamento e identificação do palmitato, oleato e linoleato de sitosterila, sitosterol, estigmasterol, 3-O-β-D-galactopiranosídeo do sitosterol, 3-O-β-Dgalactopiranosídeo do estigmasterol, 3-O-β-D-glicopiranosídeo do sitosterol e uma mistura de ácidos anacárdicos (monoeno e dieno do extrato etanólico de cascas do caule de Anacardium occidentale L., Anacardiaceae, bem como do sitosterol, estigmasterol, lupeol, β-amirina, catequina e epicatequina do extrato etanólico do tegumento da castanha de caju in natura. Os extratos EtOH da casca e do tegumento foram avaliados quanto ao conteúdo de fenóis totais e atividade antioxidante. O extrato etanólico das cascas do caule apresentou maior conteúdo de compostos fenólicos e percentual de atividade antioxidante.

Efeito do tratamento térmico na concentração de carotenóides, compostos fenólicos, ácido ascórbico e capacidade antioxidante do suco de tangerina murcote Effect of thermal treatment on the carotenoid, phenolic compound and ascorbic acid concentrations, and the antioxidant capacity of murcott tangerine juice

Directory of Open Access Journals (Sweden)

André de Souza Dutra

2012-09-01

Full Text Available Neste estudo, avaliou-se o efeito do tratamento térmico do suco de tangerina murcote em relação ao teor de carotenóides totais, ao perfil de carotenóides (luteína, zeaxantina, β-criptoxantina e β-caroteno, aos compostos fenólicos totais, ao ácido ascórbico e à capacidade antioxidante. No processo, utilizou-se um trocador de calor tubular, sendo avaliados 11 tratamentos seguindo um ensaio fatorial completo 2² com três repetições no ponto central, com quatro pontos axiais e uma região de observação de 88 a 100 ºC e 16 a 44 s. O teor de caratenóides totais decresceu de forma significativa em quase todos os tratamentos aplicados, se comparado ao valor encontrado para o suco in natura. A maioria dos tratamentos não reduziu de forma significativa os teores dos caratenóides luteína, zeaxantina e β-criptoxantina. Além disso, o teor de β-caroteno não sofreu alterações significativas em todos os tratamentos avaliados. A análise de variância mostrou que, para os caratenóides, não ocorreram interações significativas entre as variáveis temperatura e tempo. Os teores de ácido ascórbico e compostos fenólicos totais apresentaram reduções em seis condições avaliadas, ao passo que, em quatro, observou-se um aumento dos teores de compostos fenólicos totais, causado provavelmente pela evaporação da água presente no suco. A maior redução do teor de ácido ascórbico e o maior aumento para compostos fenólicos totais foi observado para o binômio 100 ºC/30 s. O teor de ácido ascórbico sofreu de forma significativa a influência da temperatura e esse processo de degradação pode ser descrito por meio de um modelo quadrático. Todos os tratamentos utilizados reduziram a capacidade antioxidante do suco, sendo mais intensa para o binômio 100 ºC/30 s. As variações observadas não alteraram de maneira considerável as características nutricionais do suco e os tratamentos térmicos realizados a 94 ºC por 16 a 44 s

Diatomáceas epilíticas de águas oligotróficas e ácidas do Sudeste do Brasil Epilithic diatoms from acidic and oligotrophic waters in Southeast Brazil

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Luís Gustavo de Castro Canani

2011-03-01

Full Text Available Poucos estudos tem abordado a flora de diatomáceas de sistemas oligotróficos do Brasil. São apresentados os resultados da composição taxonômica e distribuição espacial e temporal de diatomáceas no rio do Salto, situado no Parque Estadual do Ibitipoca, Minas Gerais (21º40'-21º44'S e 43º52'-43º55'W. As águas desse rio possuem pH entre 4,2 e 5,5 e concentração de ortofosfato entre 1,37 e 10,98 µg.L-1. O estudo baseia-se na análise de 80 amostras coletadas em oito estações no leito rochoso do rio, em janeiro e julho de 2004, períodos de chuva e estiagem, respectivamente. Um total de 15 espécies e duas variedades taxonômicas, distribuídas em oito gêneros e oito famílias foram descritas e ilustradas, com destaque para o gênero Eunotia Ehrenberg. O estudo sobre diatomáceas bentônicas em ambientes lóticos é pioneiro no estado de Minas Gerais, sendo registradas 14 novas citações, das quais Fragilariforma stevensonii Metzeltin & Lange-Bertalot, Eunotia pirarucu Metzeltin & Lange Betalot, Nupela giluwensis Vyverman & Compère e Sellaphora blackfordensis Mann & Droop são primeiros registros para o Brasil.Few studies have been done on the diatom flora of acidic and oligotrophic environments from Brazil. We present the taxonomic composition and distribution of diatoms of Salto River, situated at Ibitipoca State Park, Minas Gerais (21º40'-21º44'S; 43º52'-43º55'W. The pH values ranged from 4.2 to 5.5 and orthophosphate was between 1.37 and 10.98 µg.L-1. The study is based on the analysis of 80 samples collected at eight stations in the rocky stream bed, in January and July 2004, rainy and dry seasons, respectively. A total of 15 species and two taxonomic varieties distributed in eight genera and eight families were described and illustrated, notably the Eunotia Ehrenberg genus. The study of benthic diatoms in lotic systems is pioneer in Minas Gerais state; 14 new records were recorded of which Fragilariforma stevensonii

El fenómeno del bullying: una comparación de dos protocolos de intervención en el País Vasco

OpenAIRE

Goirigolzarri-Sáez, Sandra

2015-01-01

Este trabajo tiene como objetivo abordar el fenómeno del bullying mediante la comparación de dos protocolos de actuación llevados a cabo en el País Vasco para intervenir en esta problemática. Para la consecución de este fin, se ha dividido el marco teórico en dos partes: en la primera, se abordan los aspectos más importantes dentro del fenómeno del bullying como son su definición y características, el perfil de los participantes, las consecuencias psicológicas, el rol de la fam...

Fen (n=1–6) clusters chemisorbed on vacancy defects in graphene: Stability, spin-dipole moment, and magnetic anisotropy

KAUST Repository

Haldar, Soumyajyoti; Pujari, Bhalchandra S.; Bhandary, Sumanta; Cossu, Fabrizio; Eriksson, Olle; Kanhere, Dilip G.; Sanyal, Biplab

2014-01-01

In this work, we have studied the chemical and magnetic interactions of Fen (n=1–6) clusters with vacancy defects (monovacancy to correlated vacancies with six missing C atoms) in a graphene sheet by ab initio density functional calculations

Fen Eğitiminde Öğrenme Döngüsü Modelleri

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Yüksel Keleş

2011-11-01

Full Text Available Öğrenme döngüleri yapılandırıcı yaklaşımla fen eğitimi için geliştirilmiş modellerdir. Öğrenme döngüsü modelleri birbirini izleyen 3, 5 veya 7 evreden oluşmaktadır, bu evreler birbirinden ayrı ya da doğrusal değildir. Öğrenme döngüsü uygulamalarının yaratıcı ve eleştirel düşünme için öğrencileri teşvik etmesi ve bilime karşı olumlu tutum geliştirilmesi beklenmektedir. Kavramların daha iyi anlaşılmasına ve öğrencilerde ileri düşünme yeteneklerinin gelişmesine yardımcı olacağı düşünülmektedir. Bu makalede 5E ve 7E modellerinin her bir evresindeki öğrenci ve öğretmen rolleri üzerinde durulmaktadır. Model üzerinde gerçekleştirilen çalışmaların sonuçlarına dayanılarak modelin sağlayacağı olası faydalar tartışılmaktadır. Fen eğitiminde öğrenme döngüsü uygulamalarının yaygınlaştırılması amacıyla, öğretmen yetiştirme süreçlerinde öğrenme döngüsü modellerine yer verilmesi önerilmektedir.

Partitioning of soil CO2 efflux in un-manipulated and experimentally flooded plots of a temperate fen

Science.gov (United States)

Wunderlich, S.; Borken, W.

2012-08-01

Peatlands store large amounts of organic carbon, but the carbon stock is sensitive to changes in precipitation or water table manipulations. Restoration of drained peatlands by drain blocking and flooding is a common measure to conserve and augment the carbon stock of peatland soils. Here, we report to what extent flooding affected the contribution of heterotrophic and rhizosphere respiration to soil CO2 efflux in a grass-dominated mountain fen in Germany. Soil CO2 efflux was measured in three un-manipulated control plots and three flooded plots in two consecutive years. Flooding was achieved by permanent irrigation during the growing seasons. Radiocarbon signatures of CO2 from different sources including soil CO2 efflux, incubated peat cores and live grass roots were repeatedly analyzed for partitioning of soil CO2 efflux. Additionally, heterotrophic respiration and its radiocarbon signature were determined by eliminating rhizosphere respiration in trenched subplots (only control). In the control plots, rhizosphere respiration determined by 14C signatures contributed between 47 and 61% during the growing season, but was small (4 ± 8%) immediately before budding. Trenching revealed a smaller rhizosphere contribution of 33 ± 8% (2009) and 22 ± 9% (2010) during growing seasons. Flooding reduced annual soil CO2 efflux of the fen by 42% in 2009 and by 30% in 2010. The reduction was smaller in 2010 mainly through naturally elevated water level in the control plots. A one-week interruption of irrigation caused a strong short-lived increase in soil CO2 efflux, demonstrating the sensitivity of the fen to water table drawdown near the peat surface. The reduction in soil CO2 efflux in the flooded plots diminished the relative proportion of rhizosphere respiration from 56 to 46%, suggesting that rhizosphere respiration was slightly more sensitive to flooding than heterotrophic respiration.

Migração internacional de trabalho qualificado e o fenômeno do brain drain no Brasil

OpenAIRE

FARIA, Bruna Maia de

2008-01-01

Maia de Faria, Bruna; Barrantes Hidalgo, Álvaro. Migração internacional de trabalho qualificado e o fenômeno do brain drain no Brasil. 2008. Dissertação (Mestrado). Programa de Pós-Graduação em Economia, Universidade Federal de Pernambuco, Recife, 2008.

Caracterização fenólica das uvas 'Alicante' e 'Syrah' cultivadas em safra fora de época

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Alessandro Jefferson Sato

2012-03-01

Full Text Available O objetivo do trabalho foi caracterizar a evolução da maturação fenólica das videiras 'Alicante' e 'Syrah' (Vitis vinifera L. cultivadas fora de época. A área experimental foi instalada em uma propriedade pertencente à Vinícola Intervin®, localizada em Maringá-PR. Os vinhedos foram estabelecidos em julho de 2001, e as plantas foram conduzidas no sistema latada (4,0 x 1,5 m, enxertadas sobre o porta-enxerto IAC 766 'Campinas'. As podas curtas de formação (duas gemas foram realizadas no fim do mês de agosto de 2007 e 2008, e as podas longas de produção (oito gemas foram realizadas no fim de fevereiro de 2008 e 2009. As avaliações foram realizadas em duas safras fora de época (2008 e 2009, a partir do início da maturação das uvas até sete dias após a colheita. Foram utilizadas 20 plantas representativas de cada variedade. Para a evolução da maturação fenólica das uvas, foi determinado o teor de antocianinas e o índice de polifenóis totais (IPT do mosto das bagas. Por ocasião da colheita, foi avaliado o teor de resveratrol do mosto das uvas. Para a 'Alicante', a média do teor de antocianinas foi de 55,4 mg 100g-1, IPT de 474,0 mg 100g-1 e teor de resveratrol de 7,6 µg g-1. Para a 'Syrah', observou-se teor médio de antocianinas de 44,8 mg 100g-1, IPT de 487,7 mg 100g-1 e teor de resveratrol de 6,4 µg g-1. Considera-se que a evolução da maturação fenólica das uvas estudadas neste trabalho (progressiva para antocianinas e oscilatória para IPT e o teor dos compostos fenólicos no momento da colheita são adequados para que estas sejam utilizadas como matéria-prima na elaboração de vinhos finos.

Using multi-proxy palaeoecology to test a relict status of refugial populations of calcareous-fen species in the Western Carpathians

Czech Academy of Sciences Publication Activity Database

Hájková, Petra; Horsák, M.; Hájek, Michal; Jankovská, Vlasta; Jamrichová, Eva; Moutelíková, J.

2015-01-01

Roč. 25, č. 4 (2015), s. 702-715 ISSN 0959-6836 Institutional support: RVO:67985939 Keywords : biodiversity * calcareous fen * fossil record * Holocene extinction * Western Carpathians Subject RIV: EF - Botanics Impact factor: 2.135, year: 2015

Water stress index for alkaline fen habitat based on UAV and continuous tower measurements of canopy infrared temperature

Science.gov (United States)

Ciężkowski, Wojciech; Jóźwiak, Jacek; Chormański, Jarosław; Szporak-Wasilewska, Sylwia; Kleniewska, Małgorzata

2017-04-01

This study is focused on developing water stress index for alkaline fen, to evaluate water stress impact on habitat protected within Natura 2000 network: alkaline fens (habitat code:7230). It is calculated based on continuous measurements of air temperature, relative humidity and canopy temperature from meteorological tower and several UAV flights for canopy temperature registration. Measurements were taken during the growing season in 2016 in the Upper Biebrza Basin in north-east Poland. Firstly methodology of the crop water stress index (CWSI) determination was used to obtained non-water stress base line based on continuous measurements (NWSBtower). Parameters of NWSBtower were directly used to calculate spatial variability of CWSI for UAV thermal infrared (TIR) images. Then for each UAV flight day at least 3 acquisition were performed to define NWSBUAV. NWSBUAV was used to calculate canopy waters stress for whole image relative to the less stressed areas. The spatial distribution of developed index was verified using remotely sensed indices of vegetation health. Results showed that in analysed area covered by sedge-moss vegetation NWSB cannot be used directly. The proposed modification of CWSI allows identifying water stress in alkaline fen habitats and was called as Sedge-Moss Water Stress Index (SMWSI). The study shows possibility of usage remotely sensed canopy temperature data to detect areas exposed to the water stress on wetlands. This research has been carried out under the Biostrateg Programme of the Polish National Centre for Research and Development (NCBiR), project No.: DZP/BIOSTRATEG-II/390/2015: The innovative approach supporting monitoring of non-forest Natura 2000 habitats, using remote sensing methods (HabitARS).

Quantificação de compostos fenólicos e ácido ascórbico em frutos e polpas congeladas de acerola, caju, goiaba e morango

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Juliana Mesquita Freire

2013-12-01

Full Text Available O crescente interesse da população pela promoção da saúde vem despertando a atenção dos consumidores por alimentos ricos em antioxidantes, combinado com a praticidade do consumo de sucos de frutos processados. O presente trabalho objetivou quantificar e avaliar a capacidade antioxidante de compostos fenólicos e ácido ascórbico em frutas in natura e polpas congeladas. As frutas in natura e polpas congeladas obtidas na região de Lavras - MG foram submetidas à quantificação de compostos fenólicos e ácido ascórbico e os respectivos extratos acetônico-etanólico e acetônico-metanólico. Foram determinadas suas atividades antioxidantes pelos métodos radicalares DPPH e ABTS. O extrato acetônico-metanólico foi mais efetivo para extrair os compostos antioxidantes das amostras. Apenas as polpas congeladas de acerola apresentaram uma redução do teor de compostos fenólicos em relação ao fruto. Para o teor de ácido ascórbico, houve uma redução nas polpas congeladas de acerola e goiaba. As amostras de acerola apresentaram os maiores teores de compostos fenólicos, ácido ascórbico e atividade antioxidante em relação aos demais frutos analisados.

Substâncias fenólicas, flavonoides e capacidade antioxidante em erveiras sob diferentes coberturas do solo e sombreamentos

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T.S. FERRERA

Full Text Available RESUMO Objetivou neste trabalho analisar a concentração de polifenóis totais, flavonoides e capacidade antioxidantes por meio dos métodos ABTS e FRAP, em erveiras jovens cultivadas em solo coberto e com sombreamento. Mudas de erva-mate foram submetidas aos tratamentos com solos cobertos e desnudos em sombreamentos de 0, 18, 35 e 50%, após sete e onze meses de cultivo, verão e outono, respectivamente. Foram coletadas folhas maduras para realização dos extratos utilizados para as análises de compostos fenólicos por meio da reação de oxirredução com reagente de Folin-Ciocalteu, flavonoides por método colorimétrico e capacidade antioxidante por frente ao radical ABTS e poder de redução do ferro (FRAP. O teor de compostos fenólicos foi maior nos tratamentos com 35% de sombreamento em comparação ao grupo dos flavonoides e capacidade antioxidante, o que foi demonstrado pela correlação do sombreamento com estes parametros. No método FRAP a maior correlação demonstra que o outono é a melhor época de colheita por apresentar maior concentração de compostos fitoquímicos. Ficou evidente a influência positiva dos sombreamentos (35 e 50% no teor de compostos fenólicos e flavonoides relacionados à capacidade antioxidante e à qualidade da erva-mate para atender ao mercado consumidor.

Atividade antimicrobiana, antioxidante e teor de compostos fenólicos em casca e amêndoa de frutos de manga

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Kettelin Aparecida Arbos

2013-04-01

Full Text Available O processamento industrial de frutos de manga gera elevada quantidade de resíduos agroindustriais, representados pelas cascas e sementes (amêndoa, os quais, sem aplicação viável, acabam sendo descartados diretamente no meio ambiente. Esses resíduos são ricos em compostos bioativos, amplamente reconhecidos pelas suas propriedades promotoras da saúde e em aplicações tecnológicas. Os objetivos foram avaliar as atividades antimicrobiana e antioxidante e o teor de compostos fenólicos de dois extratos: um obtido da casca (FC e outro da amêndoa (FA de manga variedade 'Tommy Atkins'. O teor de compostos fenólicos totais variou de 3.123 a 6.644 mg de catequina/100 g. Os extratos FC e FA demonstraram relevante atividade antimicrobiana frente às cepas das bactérias Escherichia coli, Salmonella sp., Pseudomonas aeruginosa . Staphylococcus aureus, determinadas pelo método de difusão em disco. A ação antioxidante de FC e FA aumentou com o aumento das concentrações testadas, atingindo o valor máximo de 88% (FC. Em todas as concentrações testadas os extratos FC apresentaram ação antioxidante significativamente superior às respectivas concentrações dos extratos FA. Esses resultados sugerem potencial aplicação dos resíduos de manga como fonte de compostos fenólicos, substâncias antimicrobianas e antioxidantes, podendo ser explorados pelas indústrias de alimentos.

Feminización del fenómeno migratorio ecuatoriano

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Jorge Moreno Egas

2009-12-01

Full Text Available La crítica situación económica y política del Ecuador en la última década del XX fue la coyuntura que agudizó el fenómeno migratorio presente desde mediados de ese siglo. América Latina, Norte América y en los últimos tiempos Europa, particularmente España e Italia son los lugares de destino de los ecuatorianos. Este hecho se caracteriza por ser amplio y diverso. Los migrantes provienen de todas las clases sociales, es multigeneracional y particularmente femenino. Los efectos de la crisis y situaciones particulares de violencia y marginación han obligado a las mujeres a buscar alternativas de trabajo fuera del país. La feminización del fenómeno migratorio, dentro o fuera de la legalidad, más allá de su lado bueno, - remesas para la familia que queda a tras, éxitos personales en los lugares de acogida y la perspectiva de reunificación de la familia -, coloca a las migrantes en situaciones de vulnerabilidad, origina rupturas familiares y pone en riesgo la seguridad de los niños por privárseles del papel protagónico que las madres cumplen en su crianza.___________________ABSTRACT:Ecuador’s critical economic and political situation during the last decade of the Twentieth Century was the trend that worsened the emigration phenomenon present from the middle of the century. Latin America, North America and, lately, Europe, particularly Spain and Italy, are the destinations for Ecuadorians. This fact is characterized by being broad and diverse. Emigrants come from all social classes, are multi-generational and particularly female. The effects of the crisis and the specific situations of violence and marginalization have forced women to seek options for work outside the country. The feminization of the emigration phenomenon inside or outside the law other than its good side – remittances to the family that stayed behind, personal success in the places where they are received and the perspective of reuniting with family �

Potencial de actividad antioxidante de extractos fenólicos de Theobroma cacao L. (cacao)

OpenAIRE

Quiñones Gálvez, Janet; Trujillo Sánchez, Reinaldo; Capdesuñer Ruiz, Yanelis; Quirós Molina, Yemeys; Hernández de la Torre, Martha

2013-01-01

Introducción: Theobroma cacao L. (cacao), familia Sterculiaceae, es una planta rica en fenoles, los cuales en las plantas son de especial interés por su potente actividad antioxidante, dada esencialmente por sus propiedades redox, que pueden desempeñar un papel importante en la absorción y neutralización de los radicales libres. Objetivos: seleccionar un clon promisorio en la producción de compuestos fenólicos, determinar los órganos con mayor contenido de fenoles, establecer el cultivo in vi...

Fenólicos totais e atividade antioxidante do extrato aquoso de broto de feijão-mungo (Vigna radiata L. Total phenolics and antioxidant activity of the aqueous extract of mung bean sprout (Vigna radiata L.

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Vera Lúcia Arroxelas Galvão de Lima

2004-03-01

Full Text Available OBJETIVO: Considerando a importância dos compostos fenólicos em alimentos e que o broto de feijão-mungo vem sendo incluído na culinária brasileira, este estudo teve como objetivo quantificar o teor de fenólicos totais deste vegetal e avaliar a ação antioxidante do seu extrato aquoso. MÉTODOS: Os compostos fenólicos foram extraídos por quatro sistemas de solventes e dois métodos de extração, os quais foram diferenciados no tempo (2 e 1h e número de extrações (2 e 3 extrações. Os fenólicos totais dos extratos foram quantificados por método espectrofotométrico. RESULTADOS: Os extratos obtidos com água à temperatura ambiente (28ºC, nos dois métodos de extração, foram os que apresentaram maior quantidade de fenólicos totais, sem contudo apresentar diferença significativa entre eles. O método II, que consistiu de três extrações em 1h, pode ser considerado o melhor por ter utilizado menor tempo de extração. O extrato aquoso em sistema modelo b-caroteno/ácido linoléico exibiu ação antioxidante (48,07% de inibição da oxidação, entretanto foi inferior ao padrão BHT. CONCLUSÃO: O broto de feijão-mungo possui considerável quantidade de fenólicos totais, compostos responsáveis por sua ação antioxidante, cujo consumo pode proporcionar efeitos benéficos à saúde.OBJECTIVE: Considering the importance of phenolic compounds in foods and the increasing consumption of mung bean sprouts in Brazil, this study had the objective of quantifying the total phenolic content in this vegetable and to assess the antioxidant activity of its aqueous extract. METHODS: The phenolic compounds were extracted by four solvent systems and two extraction methods, which were different in time (2 and 1h and in number of extractions (2 and 3 extractions. The total phenolic content of the extracts were quantified by the spectrophotometric method. RESULTS: The extracts obtained with water at room temperature (28ºC in both extraction

Bio-optical characterization in an ultra-oligotrophic region: the North central Red Sea

KAUST Repository

Kheireddine, Malika

2015-04-01

Until recently, satellite-derived ocean color observations have been the only means of evaluating optical variability of the Red Sea. During a cruise in autumn 2014, we investigated the variability of Inherent Optical Properties (IOPs) in the North Central Red Sea (NCRS) with a particular focus on the particulate backscattering coefficient, bbp, and colored dissolved organic matter, CDOM, absorption. To our knowledge, these are some of the measurements of these properties in the Red Sea. The IOPs are derived from the concentration and physical properties of suspended particles in the ocean. They provide a simple description of the influence of these particles on the light within the water column. Bio-optical relationships found for ultra-oligotrophic waters of the six stations sampled significantly depart from the mean standard relationships provided for the global ocean, showing the peculiar character of the Red Sea. These optical anomalies relate to the specific biological and environmental conditions occurring in the Red Sea ecosystem. Specifically, the surface specific phytoplankton absorption coefficients are lower than the values predicted from the global relationships due to a high proportion of relatively large sized phytoplankton. Conversely, bbp values are much higher than the mean standard values for a given chlorophyll-a concentration, Chl a. This presumably results from the influence of highly refractive submicrometer particles of Saharan origin in the surface layer of the water column.

Leaf-litter microfungal community on poor fen plant debris in Torfy Lake area (Central Poland)

OpenAIRE

Mateusz Wilk; Agnieszka Banach; Julia Pawłowska; Marta Wrzosek

2014-01-01

The purpose of this study was to initially evaluate the species diversity of microfungi growing on litter of 15 plant species occurring on the poor fen and neighbouring area of the Torfy Lake, Masovian voivodeship, Poland. The lake is located near the planned road investment (construction of the Warsaw southern express ring road S2). The place is biologically valuable as there are rare plant communities from Rhynchosporion albae alliance protected under the Habitats Directive adopted by the E...

Efeito de diferentes métodos de extração sobre a atividade antioxidante e o perfil de compostos fenólicos da folha de mandioca

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Mírian Aparecida Isidro Santos

Full Text Available Resumo Folhas de mandioca (Manihot esculenta Crantz são resíduos agroindustriais que apresentam potencial para o consumo humano, sendo fontes de proteínas, vitaminas, minerais e de substâncias antioxidantes, com destaque para os compostos fenólicos. No presente estudo, o objetivo foi identificar e quantificar os compostos fenólicos presentes em diferentes extratos da farinha de folhas de mandioca (FFM, cultivar Pão da China, e avaliar seu potencial antioxidante. A extração dos compostos fenólicos foi realizada utilizando três métodos de extração: a refluxo com metanol/água (50:50, v/v; b maceração com etanol/água (50:50, v/v seguido de refluxo com acetona/água (70:30, v/v; c maceração com metanol PA. A caracterização e quantificação foi realizada por cromatografia líquida de alta eficiência e a atividade antioxidante, determinada pelos métodos ABTS e β-caroteno/ácido linoleico. Foram encontrados cinco compostos fenólicos nos extratos da FFM: ácido gálico, galocatequina, catequina, ácido clorogênico e epigalocatequina, sendo a extração com metanol/água (50:50, v/v a que revelou a presença do maior número destes compostos e o maior potencial antioxidante. Entre os fenólicos da FFM, independentemente do extrato, a catequina foi o majoritário. Pode-se inferir que a atividade antioxidante dos extratos da FFM está relacionada com a presença de compostos, pois a extração com maior teor desses compostos foi a que demonstrou maior potencial antioxidante.

Compuestos fenólicos del olivo (Olea europea

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Maestro-Durán, R.

1994-08-01

Full Text Available Certain plant properties, such as the colour, the nutritional value, the resistance to microorganisms, the pharmacologic effects and the organoleptic character, are due to the phenolic compounds. It is interesting the study of phenolic compounds from olive because they:

-Inhibit Gram+ microorganisms, such as Lactobacillus, which are involved in the fermentation of the olive fruit. -Inhibit the activity of cellulases and other enzymes. -Contribute to the stability and organoleptic character of virgin olive oil. -Inhibit the effect of microorganisms involved in the anaerobic depuration of vegetation water. Thus, the phenolic compounds are the major bothersome contaminants of these wastewater. -Have pharmacologic properties (to reduce blood pressure levels. -Are natural antioxidants.

-Por su carácter antibiótico, los fenoles de la aceituna inhiben los microorganismos Gram+, como Lactobacillus, necesarios para la fermentación de aceitunas de mesa. -Inhiben la acción de las celulasas y otras enzimas. -Son los responsables de la alta estabilidad de los aceites vírgenes de oliva, así como de alguno de sus caracteres organolépticos. -Inhiben la acción de los microorganismos responsables de la depuración anaerobia de los alpechines y son las sustancias contaminantes de estas aguas residuales cuya degradación para eliminar la DQO presenta más dificultades. -Tienen propiedades

Microbial methane production in oxygenated water column of an oligotrophic lake

Science.gov (United States)

Grossart, Hans-Peter; Frindte, Katharina; Dziallas, Claudia; Eckert, Werner; Tang, Kam W.

2011-01-01

The prevailing paradigm in aquatic science is that microbial methanogenesis happens primarily in anoxic environments. Here, we used multiple complementary approaches to show that microbial methane production could and did occur in the well-oxygenated water column of an oligotrophic lake (Lake Stechlin, Germany). Oversaturation of methane was repeatedly recorded in the well-oxygenated upper 10 m of the water column, and the methane maxima coincided with oxygen oversaturation at 6 m. Laboratory incubations of unamended epilimnetic lake water and inoculations of photoautotrophs with a lake-enrichment culture both led to methane production even in the presence of oxygen, and the production was not affected by the addition of inorganic phosphate or methylated compounds. Methane production was also detected by in-lake incubations of lake water, and the highest production rate was 1.8–2.4 nM⋅h−1 at 6 m, which could explain 33–44% of the observed ambient methane accumulation in the same month. Temporal and spatial uncoupling between methanogenesis and methanotrophy was supported by field and laboratory measurements, which also helped explain the oversaturation of methane in the upper water column. Potentially methanogenic Archaea were detected in situ in the oxygenated, methane-rich epilimnion, and their attachment to photoautotrophs might allow for anaerobic growth and direct transfer of substrates for methane production. Specific PCR on mRNA of the methyl coenzyme M reductase A gene revealed active methanogenesis. Microbial methane production in oxygenated water represents a hitherto overlooked source of methane and can be important for carbon cycling in the aquatic environments and water to air methane flux. PMID:22089233

In situ proteo-metabolomics reveals metabolite secretion by the acid mine drainage bio-indicator, Euglena mutabilis

Science.gov (United States)

Halter, David; Goulhen-Chollet, Florence; Gallien, Sébastien; Casiot, Corinne; Hamelin, Jérôme; Gilard, Françoise; Heintz, Dimitri; Schaeffer, Christine; Carapito, Christine; Van Dorsselaer, Alain; Tcherkez, Guillaume; Arsène-Ploetze, Florence; Bertin, Philippe N

2012-01-01

Euglena mutabilis is a photosynthetic protist found in acidic aquatic environments such as peat bogs, volcanic lakes and acid mine drainages (AMDs). Through its photosynthetic metabolism, this protist is supposed to have an important role in primary production in such oligotrophic ecosystems. Nevertheless, the exact contribution of E. mutabilis in organic matter synthesis remains unclear and no evidence of metabolite secretion by this protist has been established so far. Here we combined in situ proteo-metabolomic approaches to determine the nature of the metabolites accumulated by this protist or potentially secreted into an AMD. Our results revealed that the secreted metabolites are represented by a large number of amino acids, polyamine compounds, urea and some sugars but no fatty acids, suggesting a selective organic matter contribution in this ecosystem. Such a production may have a crucial impact on the bacterial community present on the study site, as it has been suggested previously that prokaryotes transport and recycle in situ most of the metabolites secreted by E. mutabilis. Consequently, this protist may have an indirect but important role in AMD ecosystems but also in other ecological niches often described as nitrogen-limited. PMID:22237547

Fatores implicados no fenómeno de bullying em contexto escolar: revisão integrada da literatura Factores implicados en el fenómeno de acoso en contexto escolar: revisión integrada de la literatura Factors related to the bullying phenomenon in school context: integrative literature review

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Rita Lopez

2011-12-01

Full Text Available As evidências científicas sugerem que o bullying é um fenómeno cada vez mais frequente no contexto escolar, ao qual está inerente um vasto número de consequências para a saúde, pelo que, a sua prevenção deve constituir uma área prioritária. Com o objetivo de identificar os fatores implicados no fenómeno do bullying em contexto escolar, efetuou-se uma revisão da literatura de forma sistematizada na Biblioteca do Conhecimento Online (b-on com as seguintes palavras-chave: “bullying/bullying school context”, considerando os seguintes critérios de inclusão: participantes (estudantes do 2º e 3º ciclo; variáveis em estudo (fatores implicados no fenómeno do bullying, sem restrições relativas ao desenho dos estudos. Foram identificados 351 artigos, dos quais não foi possível aceder a 132. Considerando os critérios de inclusão, foram eliminados 203 artigos, os restantes 16 foram analisados. Da análise dos resultados dos estudos que integram esta revisão da literatura, emergem quatro tipologias de fatores, os fatores relacionados com as variáveis sociodemográficas, os fatores relacionados com as variáveis pessoais, os relativos à dimensão familiar e ainda os relacionados com as variáveis escolares. Em função destas tipologias, identificaram-se diversos fatores protetores e fatores de risco implicados no fenómeno de bullying.Las evidencias científicas sugieren que el acoso es un fenómeno cada vez más frecuente en el contexto escolar, al cual está inherente un vasto número de consecuencias para la salud, por lo que su prevención debe constituir un área prioritaria. Con el objetivo de identificar a los factores implicados en el fenómeno del acoso en contexto escolar, se efectuó una revisión de la literatura de forma sistematizada en la “Biblioteca do Conhecimento Online” (b-on con las siguientes palabras clave: “bullying/bullying school context”, considerando los siguientes criterios de inclusi

Computerbasiert prüfen [Computer-based Assessment

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Frey, Peter

2006-08-01

Full Text Available [english] Computer-based testing in medical education offers new perspectives. Advantages are sequential or adaptive testing, integration of movies or sound, rapid feedback to candidates and management of web-based question banks. Computer-based testing can also be implemented in an OSCE examination. In e-learning environments formative self-assessment are often implemented and gives helpful feedbacks to learners. Disadvantages in high-stake exams are the high requirements as well for the quality of testing (e.g. standard setting as additionally for the information technology and especially for security. [german] Computerbasierte Prüfungen im Medizinstudium eröffnen neue Möglichkeiten. Vorteile solcher Prüfungen liegen im sequentiellen oder adaptiven Prüfen, in der Integration von Bewegtbildern oder Ton, der raschen Auswertung und zentraler Verwaltung der Prüfungsfragen via Internet. Ein Einsatzgebiet mit vertretbarem Aufwand sind Prüfungen mit mehreren Stationen wie beispielsweise die OSCE-Prüfung. Computerbasierte formative Selbsttests werden im Bereiche e-learning häufig angeboten. Das hilft den Lernenden ihren Wissensstand besser einzuschätzen oder sich mit den Leistungen anderer zu vergleichen. Grenzen zeigen sich bei den summativen Prüfungen beim Prüfungsort, da zuhause Betrug möglich ist. Höhere ärztliche Kompetenzen wie Untersuchungstechnik oder Kommunikation eigenen sich kaum für rechnergestützte Prüfungen.

Long-Term Trends and Temporal Synchrony in Plankton Richness, Diversity and Biomass Driven by Re-Oligotrophication and Climate across 17 Danish Lakes

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Korhan Özkan

2016-09-01

Full Text Available A two-decade (1989–2008 time series of lake phyto- and zooplankton, water characteristics and climate in 17 Danish lakes was analysed to examine the long term changes and the effects of lake restoration efforts. The analyses of the pair-wise correlations across time series revealed a strong synchrony in climatic variables among the lakes. A significant, but weak increase in air temperature was observed and resulted in a corresponding increase in surface water temperature only in summer. Lake physico-chemical variables had weaker synchrony than climatic variables. Synchrony in water temperature and stratification was stronger than lake chemistry as the former is mostly affected by atmospheric energy flux. Synchrony in the taxonomic richness of the plankton groups and phytoplankton biomass was apparent, to a similar degree as observed for lake chemistry. The synchrony and the temporal trends in lake chemistry and plankton were more pronounced for the lakes with strong re-oligotrophication. Phytoplankton biomass decreased and plankton richness increased in these lakes, with a shift from Chlorophyta dominance towards more heterogeneous phytoplankton communities. Notably, a widespread significant positive trend in plankton richness was observed not only in lakes with strong re-oligotrophication but across all lakes. The widespread increase in plankton richness coincided with widespread decrease in phosphate and total nitrogen concentrations, as well as with the trends in climate indicating a likely joint effect of nutrient reduction and climate in driving lake plankton. However, temporal changes and synchrony as well as the recovery of richness and composition of lake plankton more coherently corresponded with the nutrient loading reduction across the Danish landscape, while the role of climate control of the lake plankton was less pronounced.

Lucio's phenomenon: another case reported in Brazil Fenômeno de Lúcio: mais um caso relatado no Brazil

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Rodrigo Monteiro

2012-04-01

Full Text Available Lucio's phenomenon is defined as a variant of type 2 leprosy reaction. It is a rare event, occurring in the evolution of leprosy of Lucio and other forms of lepromatous leprosy. It has an exacerbated proliferation of Hansen bacilli in its pathophysiology, which invade blood vessel walls and injure endothelial cells, causing endothelial proliferation and decreasing the vascular lumen. This fact, associated with inflammatory reactions and changes in the coagulation system causes vascular thrombosis, ischemia, infarction and tissue necrosis, leading to the histopathological characteristic of the phenomenon. We report a case of lepromatous leprosy with irregular treatment that developed Lucio's phenomenon. Treatment with multidrug therapy, antibiotics, steroids and thalidomide achieved a favorable outcome.Define-se o fenômeno de Lúcio como uma variante da reação hansênica do tipo 2. Evento raro, que ocorre na evolução da hanseníase de Lúcio e de outras formas de hanseníase virchowiana. Tem na sua fisiopatologia uma proliferação exacerbada dos bacilos de Hansen, que invadem a parede dos vasos sanguíneos e agridem as células endoteliais, causando proliferação endotelial e diminuição do lúmen vascular, fato este, que associado a reações inflamatórias e a alterações no sistema da coagulação, causa trombose vascular, isquemia, infarto e necrose tecidual, gerando as alterações histopatológicas características do fenômeno. Relatamos um caso de hanseníase virchowiana, com tratamento irregular, que desenvolveu o fenômeno de Lúcio. Recebeu tratamento com poliquimioterapia, antibióticos, corticosteróide e talidomida, evoluindo com desfecho clínico favorável.

Fe-N and (Fe, Ni)-N Fine Powders for Magnetic Recording

International Nuclear Information System (INIS)

Chen Ziyu; Li Fashen

1998-01-01

Combining Moessbauer spectroscopy with magnetic property measurement, we have studied Fe-N and (Fe, Ni)-N powders for magnetic recording. The typical particles of the core (α-Fe)/shell (γ'-Fe 4 N) structure have been successfully prepared. All the products are stabilized in a multi-organic solution. It has been found that the coercivity can be changed from 300 to 800 Oe by adjusting the shape of the particles. The special saturation magnetization of the particles can be adjusted from 120 to 180emu/g and their chemical stability is improved by substituting nickel for iron in γ'-Fe 4 N. Following experiments for corrosion resistance, it is expected that (Fe, Ni)-N and the core/shell particles will be applied as recording media in the near future

Fe-N and (Fe, Ni)-N Fine Powders for Magnetic Recording

Energy Technology Data Exchange (ETDEWEB)

Chen Ziyu; Li Fashen [Lanzhou University, Department of Physics (China)

1998-12-15

Combining Moessbauer spectroscopy with magnetic property measurement, we have studied Fe-N and (Fe, Ni)-N powders for magnetic recording. The typical particles of the core ({alpha}-Fe)/shell ({gamma}'-Fe{sub 4}N) structure have been successfully prepared. All the products are stabilized in a multi-organic solution. It has been found that the coercivity can be changed from 300 to 800 Oe by adjusting the shape of the particles. The special saturation magnetization of the particles can be adjusted from 120 to 180emu/g and their chemical stability is improved by substituting nickel for iron in {gamma}'-Fe{sub 4}N. Following experiments for corrosion resistance, it is expected that (Fe, Ni)-N and the core/shell particles will be applied as recording media in the near future.

Heidegger: o estudo dos fenômenos humanos baseados na existência humana como ser-aí (Dasein

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Ida Elizabeth Cardinalli

2015-08-01

Full Text Available O presente artigo pretende esclarecer a posição crítica do filósofo Martin Heidegger, explicitada no livro Seminários de Zollikon, em relação à transposição do método da ciência natural moderna para o estudo dos fenômenos humanos e apresentar sua proposição de um método mais pertinente ao estudo da existência humana. O autor propõe indicações de um método baseado na compreensão do existir humano como "ser-aí" e "ser-no-mundo" e também nos existenciais descritos em Ser e tempo, tais como espacialidade, temporalidade, ser-com-o-outro e corporeidade. Ao mesmo tempo, destaca que os fenômenos humanos não deveriam ser submetidos e circunscritos às descrições ontológicas dos existenciais, quando o método visa ao esclarecimento das experiências específicas e singulares de cada ser humano.

Phosphate release upon short- and long-term flooding of fen meadows depends on land use history and pH.

NARCIS (Netherlands)

Beltman, Boudewijn; van der Ven, P.J.M.; Verhoeven, Jos; Sarneel, J

2014-01-01

Flooding of acidified and desiccated fen meadows is a management approach for mitigating loss of plant species as well as a short-term measure to prevent flooding in urban areas. Studies have shown that flooding events can cause extreme P release from soils. We questioned whether the occurrence of

Method Development for Efficient Incorporation of Unnatural Amino Acids

KAUST Repository

Harris, Paul D.

2014-04-01

The synthesis of proteins bearing unnatural amino acids has the potential to enhance and elucidate many processes in biochemistry and molecular biology. There are two primary methods for site specific unnatural amino acid incorporation, both of which use the cell’s native protein translating machinery: in vitro chemical acylation of suppressor tRNAs and the use of orthogonal amino acyl tRNA synthetases. Total chemical synthesis is theoretically possible, but current methods severely limit the maximum size of the product protein. In vivo orthogonal synthetase methods suffer from the high cost of the unnatural amino acid. In this thesis I sought to address this limitation by increasing cell density, first in shake flasks and then in a bioreactor in order to increase the yield of protein per amount of unnatural amino acid used. In a parallel project, I used the in vitro chemical acylation system to incorporate several unnatural amino acids, key among them the fluorophore BODIPYFL, with the aim of producing site specifically fluorescently labeled protein for single molecule FRET studies. I demonstrated successful incorporation of these amino acids into the trial protein GFP, although incorporation was not demonstrated in the final target, FEN1. This also served to confirm the effectiveness of a new procedure developed for chemical acylation.

Method Development for Efficient Incorporation of Unnatural Amino Acids

KAUST Repository

Harris, Paul D.

2014-01-01

The synthesis of proteins bearing unnatural amino acids has the potential to enhance and elucidate many processes in biochemistry and molecular biology. There are two primary methods for site specific unnatural amino acid incorporation, both of which use the cell’s native protein translating machinery: in vitro chemical acylation of suppressor tRNAs and the use of orthogonal amino acyl tRNA synthetases. Total chemical synthesis is theoretically possible, but current methods severely limit the maximum size of the product protein. In vivo orthogonal synthetase methods suffer from the high cost of the unnatural amino acid. In this thesis I sought to address this limitation by increasing cell density, first in shake flasks and then in a bioreactor in order to increase the yield of protein per amount of unnatural amino acid used. In a parallel project, I used the in vitro chemical acylation system to incorporate several unnatural amino acids, key among them the fluorophore BODIPYFL, with the aim of producing site specifically fluorescently labeled protein for single molecule FRET studies. I demonstrated successful incorporation of these amino acids into the trial protein GFP, although incorporation was not demonstrated in the final target, FEN1. This also served to confirm the effectiveness of a new procedure developed for chemical acylation.

Fen Ve Teknoloji Dersi Öğretmenlerinin SBS’de Yapılan Değişikliklerle İlgili Görüşlerinin İncelenmesi

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MUSTAFA UZOĞLU

2013-09-01

Full Text Available Bu çalışma fen ve teknoloji öğretmenlerinin SBS’nin kaldırılması hakkındaki görüşlerini belirlemek amacıyla yapılmıştır. Veri toplama aracı olarak açık uçlu anketten yararlanılmıştır. Çalışmanın örneklemini 2012-2013 öğretim yılında Giresun İlinde görev yapan 51 fen ve teknoloji öğretmeni oluşturmaktadır. Açık uçlu anket formundan elde edilen sonuçlarda çalışmaya katılan fen ve teknoloji öğretmenlerinin birçoğu söz konusu sınavın kaldırılmasına karşı çıkmışlardır. Ayrıca öğretmenler sınav kaldırıldığında öğrencilerin yerleştirilmesinde sıkıntıların çıkabileceğini ifade etmişlerdir. Diğer yandan fen ve teknoloji öğretmenlerinin ortaöğretim kurumlarına öğrenci seçmek için yapılan sınavların sayısının ve şeklinin sürekli değişmesinden dolayı endişelendikleri dikkati çekmektedir. Fen ve teknoloji öğretmenleri bu durumun öğrencilerde güven kaybına, motivasyon düşüklüğüne, karamsarlığa bıkkınlığa, gelecek endişesine, adaptasyon sorununa neden olabileceğini ifade etmişlerdir.

Effects of acidity on primary productivity in lakes: phytoplankton. [Lakes Panther, Sagamore, and Woods

Energy Technology Data Exchange (ETDEWEB)

Hendrey, G R

1979-01-01

Relationships between phytoplankton communities and lake acidity are being studied at Woods Lake (pH ca. 4.9), Sagamore Lake (pH ca. 5.5), and Panther Lake (pH ca. 7.0). Numbers of phytoplankton species observed as of July 31, 1979 are Woods 27, Sagamore 38, and Panther 64, conforming to other observations that species numbers decrease with increasing acidity. Patterns of increasing biomass and productivity found in Woods Lake may be atypical of similar oligotrophic lakes in that they develop rather slowly instead of occuring very close to ice-out. Contributions of netplankton (net > 48 ..mu..m), nannoplankton (48 > nanno > 20 ..mu..m) and ultraplankton (20 > ultra >0.45 ..mu..m) to productivity per m/sup -2/ show that the smaller plankton are relatively more important in the more acid lakes. This pattern could be determined by nutrient availability (lake acidification leading to decreased availability of phosphorus). The amount of /sup 14/C-labelled dissolved photosynthate (/sup 14/C-DOM), as a percent of total productivity, is ordered Woods > Sagamore > Panther. This is consistent with a hypothesis that microbial heterotrophic activity is reduced with increasing acidity, but the smaller phytoplankton may be more leaky at low pH. (ERB)

Comparative metagenomic and metatranscriptomic analyses of microbial communities in acid mine drainage.

Science.gov (United States)

Chen, Lin-xing; Hu, Min; Huang, Li-nan; Hua, Zheng-shuang; Kuang, Jia-liang; Li, Sheng-jin; Shu, Wen-sheng

2015-07-01

The microbial communities in acid mine drainage have been extensively studied to reveal their roles in acid generation and adaption to this environment. Lacking, however, are integrated community- and organism-wide comparative gene transcriptional analyses that could reveal the response and adaptation mechanisms of these extraordinary microorganisms to different environmental conditions. In this study, comparative metagenomics and metatranscriptomics were performed on microbial assemblages collected from four geochemically distinct acid mine drainage (AMD) sites. Taxonomic analysis uncovered unexpectedly high microbial biodiversity of these extremely acidophilic communities, and the abundant taxa of Acidithiobacillus, Leptospirillum and Acidiphilium exhibited high transcriptional activities. Community-wide comparative analyses clearly showed that the AMD microorganisms adapted to the different environmental conditions via regulating the expression of genes involved in multiple in situ functional activities, including low-pH adaptation, carbon, nitrogen and phosphate assimilation, energy generation, environmental stress resistance, and other functions. Organism-wide comparative analyses of the active taxa revealed environment-dependent gene transcriptional profiles, especially the distinct strategies used by Acidithiobacillus ferrivorans and Leptospirillum ferrodiazotrophum in nutrients assimilation and energy generation for survival under different conditions. Overall, these findings demonstrate that the gene transcriptional profiles of AMD microorganisms are closely related to the site physiochemical characteristics, providing clues into the microbial response and adaptation mechanisms in the oligotrophic, extremely acidic environments.

Estudio nacional exploratorio descriptivo sobre el fenómeno de trata de personas en Colombia.

OpenAIRE

2009-01-01

Para el Ministerio del Interior y de Justicia como Secretaría Técnica del Comité Interinstitucional para la lucha contra la Trata de Personas y para la Oficina de Naciones Unidas contra la Droga y el Delito en Colombia UNODC, es un honor presentar a ustedes en esta oportunidad el primer Estudio Nacional Exploratorio Descriptivo sobre el Fenómeno de la Trata de Personas en Colombia, desarrollado por unequipo de Investigadoras e Investigadores de la Escuela de Estudios de Género de la Universid...

Conversion of a moderately rewetted fen to a shallow lake - implications for net CO2 exchange

Science.gov (United States)

Koebsch, Franziska; Glatzel, Stephan; Hofmann, Joachim; Forbrich, Inke; Jurasinski, Gerald

2013-04-01

Extensive rewetting projects to re-establish the natural carbon (C) sequestration function of degraded peatlands are currently taking place in Europe and North-America. Year-round flooding provides a robust measure to prevent periods of drought that are associated with ongoing peat mineralization and to initiate the accumulation of new organic matter. Here, we present measurements of net carbon dioxide (CO2) exchange during the gradual conversion of a moderately rewetted fen to a shallow lake. When we started our measurements in 2009, mean growing season water level (MWGL) was 0 cm. In 2010 the site was flooded throughout the year with MWGL of 36 cm. Extraordinary strong rainfalls in July 2011 resulted in a further increase of MWGL to 56 cm. Measurements of net ecosystem exchange (NEE) were conducted during growing seasons (May-October) using the Eddy Covariance method. Information about vegetation vitality was deduced from the enhanced vegetation index (EVI) based on MODIS data. Ecosystem respiration (Reco) and gross ecosystem production (GEP) were high during vegetation period 2009 (1273.4 and -1572.1 g CO2-C m-2), but decreased by 61 and 46% respectively when the fen was flooded throughout 2010. Under water-logged conditions, heterotrophic respiration declines and gas exchange is limited. Moreover, flooding is a severe stress factor for plants and decreases autotrophic respiration and photosynthesis. However, in comparison to 2010, rates of Reco and GEP doubled during the beginning of growing season 2011, indicating plastic response strategies of wetland plants to flooding. Presumably, plants were not able to cope with the further increase of water levels to up to 120 cm in June/July 2011, resulting in another drop of GEP and Reco. The effects of plant vitality on GEP were confirmed by the remote sensed vegetation index. Throughout all three growing seasons, the fen was a distinct net CO2 sink (2009: -333.3±12.3, 2010: -294.1±8.4, -352.4±5.1 g CO2-C m-2

Factors Influencing Mesostigmata Mites (Acari, Parasitiformes In The Alkaline Fen Habitats

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Salmane Ineta

2015-04-01

Full Text Available Mesostigmata mite fauna was investigated in soil of one alkaline fen at Apšuciems in the Maritime Lowland in Latvia in 2009. Thirty sample plots were selected in the following way: half of them were located in Brown Bog Rush, Schoenus ferrugineus and half — in Saw-Sedge, Cladium mariscus prevailing habitat. Soil samples were collected using a soil borer. Vegetation cover was described in accordance with Braun-Blanquet classes. Mites were extracted using modified Berlese funnels. In total, more than 28 species were recorded, of them Prozercon kochi and Pergamasus vagabundus were dominant species. Mean density of Mesostigmata mites ranged from 520 to 2140 ind./m2. Mite abundance and distribution between habitats depended on vegetation cover of the vascular plants, while moss cover and soil pH had no significant influence.

Spatial variations in microbial community composition in surface seawater from the ultra-oligotrophic center to rim of the South Pacific Gyre.

Directory of Open Access Journals (Sweden)

Qi Yin

Full Text Available Surface seawater in the South Pacific Gyre (SPG is one of the cleanest oceanic environments on earth, and the photosynthetic primary production is extremely low. Despite the ecological significance of the largest aquatic desert on our planet, microbial community composition in the ultra-oligotrophic seawater remain largely unknown. In this study, we collected surface seawater along a southern transect of the SPG during the Integrated Ocean Drilling Program (IODP Expedition 329. Samples from four distinct sites (Sites U1368, U1369, U1370 and U1371 were examined, representing ~5400 kilometers of transect line from the gyre heart to the edge area. Real-time PCR analysis showed 16S rRNA gene abundance in the gyre seawater, ranging from 5.96×10(5 to 2.55×10(6 copies ml(-1 for Bacteria and 1.17×10(3 to 1.90×10(4 copies ml(-1 for Archaea. The results obtained by statistic analyses of 16S rRNA gene clone libraries revealed the community composition in the southern SPG area: diversity richness estimators in the gyre center (Sites U1368 & U1369 are generally lower than those at sites in the gyre edge (Sites U1370 & U1371 and their community structures are clearly distinguishable. Phylogenetic analysis showed the predominance of Proteobacteria (especially Alphaproteobacteria and Cyanobacteria in bacterial 16S rRNA gene clone libraries, whereas phylotypes of Betaproteobacteria were only detected in the central gyre. Archaeal 16S rRNA genes in the clone libraries were predominated by the sequences of Marine Group II within the Euryarchaeota, and the Crenarchaeota sequences were rarely detected, which is consistent with the real-time PCR data (only 9.9 to 22.1 copies ml(-1. We also performed cultivation of heterotrophic microbes onboard, resulting in 18.9% of phylogenetically distinct bacterial isolates at least at the species level. Our results suggest that the distribution and diversity of microbial communities in the SPG surface seawater are closely

Free energy landscape of electrocatalytic CO2 reduction to CO on aqueous FeN4 center embedded graphene studied by ab initio molecular dynamics simulations

Science.gov (United States)

Sheng, Tian; Sun, Shi-Gang

2017-11-01

Experiments have found that the porphyrin-like FeN4 site in Fe-N-C materials is highly efficient for the electrochemical reduction of CO2 into CO. In this work, we investigated the reduction mechanisms on FeN4 embedded graphene layer catalyst with some explicit water molecules by combining the constrained ab initio molecular dynamics simulations and thermodynamic integrations. The reaction free energy and electron transfer in each elementary step were identified. The initial CO2 activation was identified to go through the first electron transfer to form adsorbed CO2- anion and the CO desorption was the rate limiting step in the overall catalytic cycle.

Mapeamento do fenômeno de pulsações não-radiais no DHR

Science.gov (United States)

Waelkens, A. H.; Janot Pacheco, E.

2003-08-01

Neste trabalho de IC, pretende-se estabelecer um mapa das características do fenômeno das pulsações não-radiais (PNR) no diagrama HR (DHR). Trata-se de oscilações que não mantém a homotecia radial. O fenômeno foi inicialmente descoberto no Sol nos anos 60 e hoje é detectado num grande número de objetos. Sua grande importância reside em que as pulsações descrevem a física da cavidade em que se propagam. As PNR são classificadas basicamente por suas frequências, amplitudes e certos números quânticos associados. Com o objetivo de descrever a variação desses parâmetros no DHR, procedeu-se a um extenso levantamento bibliográfico (artigos de revistas e outras fontes) cobrindo o tema. Compôs-se assim uma tabela, que será apresentada nesta comunicação, contendo os parâmetros físicos das estrelas (T, L, logg, M) e suas características de PNR, deduzidas a partir de observações fotométricas e/ou espectroscópicas. No momento, completamos os dados sobre as Anãs Brancas e Beta Cep. Apresentaremos no trabalho diagramas L-T com os últimos resultados obtidos, eventualmente com uma terceira dimensão que descreva características pulsacionais.

Ecoenzymatic stoichiometry and microbial processing of organic matter in northern bogs and fens reveals a common P limitation among peatland types

Science.gov (United States)

We compared C, N, and P concentrations in atmospheric deposition, runoff, and soil standing stocks with microbial respiration (DHA) and ecoenzyme activity (EEA) in an ombrotrophic bog (S2) and a minerotrophic fen (S3) to investigate the environmental drivers of biogeochemical cyc...

Decade-long time delays in nutrient and plant species dynamics during eutrophication and re-oligotrophication of Lake Fure 1900–2015

DEFF Research Database (Denmark)

Sand-Jensen, Kaj; Bruun, Hans Henrik; Båstrup-Spohr, Lars

2017-01-01

Fure, Denmark, spanning the transformation from pristine environmental conditions in the early 1900s through a period (1920–1970) of eutrophication – from accelerating sewage input of phosphorus (P) – and subsequent re-oligotrophication after sewage cleaning (1970–2015). We examine time delays between...... sediment release. Fifty years of eutrophication led to a reduction in aquatic macrophyte richness from 36 species to 12. Species’ responses were closely related to their growth strategy and depth distribution. Deep-growing mosses, charophytes and short angiosperms disappeared, while tall angiosperms...... in species dominance takes longer than colonization by new species. Synthesis. Time delays of P concentrations, water clarity and macrophyte richness and composition were long and complex. Neglecting growth strategies of species makes application of extinction debt and colonization credit concepts dubious...

Phosphate Release Upon Long- and Short -Term Flooding of Fen Meadows Depends on Land Use History and Soil pH

NARCIS (Netherlands)

Beltman, B.; Van Der Ven, P. J. M.; Verhoeven, J. T. A.; Sarneel, J. M.

2014-01-01

Flooding of acidified and desiccated fen meadows is a management approach for mitigating loss of plant species as well as a short-term measure to prevent flooding in urban areas. Studies have shown that flooding events can cause extreme P release from soils. We questioned whether the occurrence of

Determinants of Paracentrotus lividus sea urchin recruitment under oligotrophic conditions: Implications for conservation management.

Science.gov (United States)

Oliva, Silvia; Farina, Simone; Pinna, Stefania; Guala, Ivan; Agnetta, Davide; Ariotti, Pierre Antoine; Mura, Francesco; Ceccherelli, Giulia

2016-06-01

Sea urchins may deeply shape the structure of macrophyte-dominated communities and require the implementation of sustainable management strategies. In the Mediterranean, the identification of the major recruitment determinants of the keystone sea urchin species Paracentrotus lividus is required, so that source areas of the populations can be identified and exploitation or programmed harvesting can be spatially managed. In this study a collection of eight possible determinants, these encompassing both the biotic (larvae, adult sea urchins, fish, encrusting coralline algae, habitat type and spatial arrangement of habitats) and abiotic (substrate complexity and nutritional status) realms was considered at different spatial scales (site, area, transect and quadrat). Data from a survey including sites subject to different levels of human influence (i.e. from urbanized to protected areas), but all corresponding to an oligotrophic and low-populated region were fitted by means of a generalized linear mixed model. Despite the extensive sampling effort of benthic quadrats, an overall paucity of recruits was found, recruits being aggregated in a very small number of quadrats and in few areas. The analysis of data detected substrate complexity, and adult sea urchin and predatory fish abundances as the momentous determinants of Paracentrotus lividus recruitment. Possible mechanisms of influence are discussed beyond the implications of conservation management. Copyright © 2016 Elsevier Ltd. All rights reserved.

Análisis del fenómeno de la violencia contra los ancianos

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Celín Pérez Nájera

2010-12-01

Full Text Available El artículo presenta una revisión bibliográfica sobre el impacto social de la violencia contra los ancianos, desde la óptica criminológica. En el trabajo se utilizó como método investigativo el enfoque dialéctico-materialista de la realidad, que facilitó el engranaje de toda la investigación en diferentes etapas. Las valoraciones generalizadoras y sistematizadoras se elaboraron desde los enfoques modelativo y sistémico-estructural. Luego de analizar la diversidad de conceptos de violencia, se estableció una definición desde una formación social e histórica; existen dos principios que distinguen sus características: uno que la concibe como un fenómeno de carácter social y el teórico-ecológico, que consiste en el empleo de la fuerza física, económica o política, e implica el abuso de poder cómo único método para resolver el conflicto. Así mismo, se examinó el comportamiento de la violencia contra los ancianos en diversos países: España, Estados Unidos, Perú, Brasil, Panamá, Argentina, Colombia, Chile y Cuba. En general, son alarmantes las cifras de incidencia del fenómeno. De igual forma, en Cuba crece la victimización sobre los ancianos. Se aprecia como manifestación fundamental la violencia psicológica o emocional. Aunque existen mecanismos de denuncia, falta de divulgación y sistematicidad de acciones, que permitan enfrentar la incidencia de este mal social, que afecta a dicho grupo de riesgo de la violencia.

Vitality of aquatic plants and microbial activity of sediment in an oligotrophic lake (Lake Bohinj, Slovenia

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Tatjana SIMČIČ

2011-08-01

Full Text Available The vitality of eight macrophyte species and the microbial activity of sediment in an oligotrophic lake (Lake Bohinj, Slovenia were studied via the terminal electron transport system (ETS activity of mitochondria. The levels of ETS activity of vascular plants were as follows: Ranunculus circinatus, Myriohpyllum spicatum, Potamogeton alpinus, P. perfoliatus, P. lucens. Fontinalis antipyretica exhibited the highest ETS activity of the non-vascular plants, followed by charales Chara delicatula and C. aspera. High values enable R. circinatus, an amphibious species with rapid growth, to survive under conditions in which the water level changes throughout the season. M. spicatum, a species with broad ecological tolerance, also exhibited high ETS activity. The ETS activity of the microbial community in sediment was affected by temperature and/or the amount and origin of the organic matter. A positive correlation between the ETS activity of the sediment and that of M. spicatum and R. circinatus was measured, while negative correlations or no correlation were observed for mosses and macroalgae. The high ETS activity in sediment indicates rapid mineralization of organic matter and, in turn, sufficient nutrients for growth of macrophytes.

El abstencionismo como fenómeno político en la sociedad contemporánea

OpenAIRE

López Sánchez, Rogelio

2013-01-01

El objetivo de la presente contribución es analizar el abstencionismo como fenómeno político. En este sentido, se examinan las distintas facetas del mismo con la finalidad de acercarnos hacia un modelo de participación cívica racional en el contexto mexicano. Igualmente, se lleva a cabo una crítica en contra del monopolio partidista que deja a los ciudadanos un pequeño margen de cuestiones políticas en las cuales puedan tomar parte. This paper intention is to analyze the abstentionism as a...

Perspectivas acerca del autismo: el problema de la relación fenómeno-estructura

OpenAIRE

Sosa, Martín; Gascón, María Constanza

2015-01-01

El presente trabajo se inscribe en el proyecto de investigación en vigencia denominado "Las variedades del autismo: sistematización y evaluación de la demanda asistencial. Segunda etapa" (2015/2016) aprobado y subsidiado por la Facultad de Psicología de la Universidad Nacional de La Plata. Examinaremos en esta ocasión diversas perspectivas dentro de la orientación lacaniana respecto de la relación fenómeno-estructura en el campo de lo que se denomina autismo. Dichas perspectivas van desde la ...

Protozooplankton in the Deep Oligotrophic Traunsee (Austria) Influenced by Discharges of Soda and Salt Industries

International Nuclear Information System (INIS)

Sonntag, Bettina; Posch, Thomas; Klammer, Susanne; Griebler, Christian; Psenner, Roland

2002-01-01

Traunsee is a deep oligotrophic lake in Austria characterised by an artificial enrichment of chloride in the hypolimnion (up to 170 mg L -1 ) caused by waste disposal of soda and salt industries. Protists were collected monthly over one year, observed alive and after Quantitative Protargol Staining (ciliates) or via epifluorescence microscopy (heterotrophic flagellates). Three sites within the lake (0-40 m depths) were compared to deeper water layers from 60-160 m depths where chloride concentrations and conductivity were increased. In addition, we observed the protozooplankton of two neighbouring lakes, i.e. reference systems, during one sampling occasion. In Traunsee the abundance of ciliates was low (200-36 600 cells L -1 ) in contrast to high species diversity (at least 60 different species; H S = 2.6) throughout the year. The main pelagic species in terms of abundance were small oligotrichs and prostomatids like Rimostrombidium brachykinetum/hyalinum, Balanion planctonicum and Urotricha spp. throughout the investigation period. Among free-living heterotrophic flagellates, which occurred at densities of 40-2800 cells mL -1 , small morphotypes dominated in the pelagial. No differences at the community level between the three lakes could be observed and pelagic ciliates and flagellates seemed not to be affected by increased chloride concentrations or by enhanced conductivity

Protozooplankton in the Deep Oligotrophic Traunsee (Austria) Influenced by Discharges of Soda and Salt Industries

Energy Technology Data Exchange (ETDEWEB)

Sonntag, Bettina, E-mail: bettina.sonntag@uibk.ac.at; Posch, Thomas [University of Innsbruck, Institute of Zoology and Limnology (Austria); Klammer, Susanne [University of Innsbruck, Institute of Microbiology (Austria); Griebler, Christian [University of Tuebingen, Centre for Applied Earth Science (Germany); Psenner, Roland [University of Innsbruck, Institute of Zoology and Limnology (Austria)

2002-07-15

Traunsee is a deep oligotrophic lake in Austria characterised by an artificial enrichment of chloride in the hypolimnion (up to 170 mg L{sup -1}) caused by waste disposal of soda and salt industries. Protists were collected monthly over one year, observed alive and after Quantitative Protargol Staining (ciliates) or via epifluorescence microscopy (heterotrophic flagellates). Three sites within the lake (0-40 m depths) were compared to deeper water layers from 60-160 m depths where chloride concentrations and conductivity were increased. In addition, we observed the protozooplankton of two neighbouring lakes, i.e. reference systems, during one sampling occasion. In Traunsee the abundance of ciliates was low (200-36 600 cells L{sup -1}) in contrast to high species diversity (at least 60 different species; H{sub S} = 2.6) throughout the year. The main pelagic species in terms of abundance were small oligotrichs and prostomatids like Rimostrombidium brachykinetum/hyalinum, Balanion planctonicum and Urotricha spp. throughout the investigation period. Among free-living heterotrophic flagellates, which occurred at densities of 40-2800 cells mL{sup -1}, small morphotypes dominated in the pelagial. No differences at the community level between the three lakes could be observed and pelagic ciliates and flagellates seemed not to be affected by increased chloride concentrations or by enhanced conductivity.

Scale-location specific relations between soil nutrients and topographic factors in the Fen River Basin, Chinese Loess Plateau

Science.gov (United States)

Zhu, Hongfen; Bi, Rutian; Duan, Yonghong; Xu, Zhanjun

2017-06-01

Understanding scale- and location-specific variations of soil nutrients in cultivated land is a crucial consideration for managing agriculture and natural resources effectively. In the present study, wavelet coherency was used to reveal the scale-location specific correlations between soil nutrients, including soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), and available potassium (AK), as well as topographic factors (elevation, slope, aspect, and wetness index) in the cultivated land of the Fen River Basin in Shanxi Province, China. The results showed that SOM, TN, AP, and AK were significantly inter-correlated, and that the scales at which soil nutrients were correlated differed in different landscapes, and were generally smaller in topographically rougher terrain. All soil nutrients but TN were significantly influenced by the wetness index at relatively large scales (32-72 km) and AK was significantly affected by the aspect at large scales at partial locations, showing localized features. The results of this study imply that the wetness index should be taken into account during farming practices to improve the soil nutrients of cultivated land in the Fen River Basin at large scales.

Innovative wetland reclamation design case studies : the Suncor fen and pond 1 marsh

Energy Technology Data Exchange (ETDEWEB)

Daly, C.A. [Suncor Energy, Fort McMurray, AB (Canada); Price, J.; Rezanezhad, F. [Waterloo Univ., ON (Canada); Rochefort, L.; Graf, M. [Laval Univ., Quebec City, PQ (Canada); Russell, B. [BGC Engineering Inc., Calgary, AB (Canada)

2010-07-01

Suncor Energy Inc. is an energy company strategically focused in Canada's Athabasca oil sands region. The company has more than 40 years of experience in pioneering commercial development. This presentation discussed reclamation requirements for Suncor Energy. Reclamation objectives that were addressed in this presentation included operating approvals, biodiversity and meeting stakeholder expectations. Several photographs of reclaimed forest areas were shown along with 5 freshwater wetland types and wetland values. Two innovative wetland reclamation design case studies were also presented, described and illustrated, with particular reference to the Suncor fen and pond 1 marsh. It was concluded that future work will involve finalizing site investigation and designs, as well as construction, vegetation, and monitoring. figs.

Saturated and unsaturated salt transport in peat from a constructed fen

Science.gov (United States)

Simhayov, Reuven B.; Weber, Tobias K. D.; Price, Jonathan S.

2018-02-01

The underlying processes governing solute transport in peat from an experimentally constructed fen peatland were analyzed by performing saturated and unsaturated solute breakthrough experiments using Na+ and Cl- as reactive and non-reactive solutes, respectively. We tested the performance of three solute transport models, including the classical equilibrium convection-dispersion equation (CDE), a chemical non-equilibrium one-site adsorption model (OSA) and a model to account for physical non-equilibrium, the mobile-immobile (MIM) phases. The selection was motivated by the fact that the applicability of the MIM in peat soils finds a wide consensus. However, results from inverse modeling and a robust statistical evaluation of this peat provide evidence that the measured breakthrough of the conservative tracer, Cl-, could be simulated well using the CDE. Furthermore, the very high Damköhler number (which approaches infinity) suggests instantaneous equilibration between the mobile and immobile phases underscoring the redundancy of the MIM approach for this particular peat. Scanning electron microscope images of the peat show the typical multi-pore size distribution structures have been homogenized sufficiently by decomposition, such that physical non-equilibrium solute transport no longer governs the transport process. This result is corroborated by the fact the soil hydraulic properties were adequately described using a unimodal van Genuchten-Mualem model between saturation and a pressure head of ˜ -1000 cm of water. Hence, MIM was not the most suitable choice, and the long tailing of the Na+ breakthrough curve was caused by chemical non-equilibrium. Successful description was possible using the OSA model. To test our results for the unsaturated case, we conducted an unsaturated steady-state evaporation experiment to drive Na+ and Cl- transport. Using the parameterized transport models from the saturated experiments, we could numerically simulate the unsaturated

Assessing Phytoplankton Nutritional Status and Potential Impact of Wet Deposition in Seasonally Oligotrophic Waters of the Mid-Atlantic Bight

Science.gov (United States)

Sedwick, P. N.; Bernhardt, P. W.; Mulholland, M. R.; Najjar, R. G.; Blumen, L. M.; Sohst, B. M.; Sookhdeo, C.; Widner, B.

2018-04-01

To assess phytoplankton nutritional status in seasonally oligotrophic waters of the southern Mid-Atlantic Bight, and the potential for rain to stimulate primary production in this region during summer, shipboard bioassay experiments were performed using natural seawater and phytoplankton collected north and south of the Gulf Stream. Bioassay treatments comprised iron, nitrate, iron + nitrate, iron + nitrate + phosphate, and rainwater. Phytoplankton growth was inferred from changes in chlorophyll a, inorganic nitrogen, and carbon-13 uptake, relative to unamended control treatments. Results indicated the greatest growth stimulation by iron + nitrate + phosphate, intermediate growth stimulation by rainwater, modest growth stimulation by nitrate and iron + nitrate, and no growth stimulation by iron. Based on these data and analysis of seawater and atmospheric samples, nitrogen was the proximate limiting nutrient, with a secondary limitation imposed by phosphorus. Our results imply that summer rain events increase new production in these waters by contributing nitrogen and phosphorus, with the availability of the latter setting the upper limit on rain-stimulated new production.

Modern distribution patterns of snails and plants in the Western Carpathian spring fens: is it a result of historical development?

Czech Academy of Sciences Publication Activity Database

Horsák, M.; Hájek, Michal; Dítě, D.; Tichý, L.

2007-01-01

Roč. 73, č. 1 (2007), s. 53-60 ISSN 0260-1230 Grant - others:GA AV ČR(CZ) KJB601630501; GA AV ČR(CZ) KJB6163302 Program:KJ Institutional research plan: CEZ:AV0Z60050516 Keywords : Snails * plants * rich fens Subject RIV: EF - Botanics Impact factor: 1.032, year: 2007

Representação e significação nos fenômenos comunicacionais

Directory of Open Access Journals (Sweden)

Luís Carlos Lopes

2001-01-01

Full Text Available Este trabalho consiste em uma investigação teórica sobre a importância das teorias da representação, significação e interpretação para o estudo dos fenômenos comunicacionais. O autor explica o que entende por comunicação e seus estudos. Discute algumas das bases epistemológicas dos estudos comunicacionais, em termos de universalidade, particularidade e naturalização. Baseia seu trabalho nas obras de Bourdieu, Debord, Canclini, Martín-Barbero, Sloterdijk, Habermas e, fundamentalmente, na de Putnam. 

Cyberbullying : a faceta de um fenómeno em jovens universitários portugueses

OpenAIRE

Francisco, Sofia Mateus

2012-01-01

Tese de mestrado, Psicologia (Secção de Psicologia da Educação e da Orientação), Universidade de Lisboa, Faculdade de Psicologia, 2012 Com a crescente utilização das novas tecnologias de informação e comunicação (TIC) nascem grandes vantagens para os jovens, mas também a esta utilização acrescem alguns riscos. Um desses riscos diz respeito ao cyberbullying. Assim, o presente estudo pretende dar a conhecer o fenómeno em estudantes do ensino superior, através da aplicação do Questionário de ...

DNA Polymerase α (swi7) and the Flap Endonuclease Fen1 (rad2) Act Together in the S-Phase Alkylation Damage Response in S. pombe

Science.gov (United States)

Koulintchenko, Milana; Vengrova, Sonya; Eydmann, Trevor; Arumugam, Prakash; Dalgaard, Jacob Z.

2012-01-01

Polymerase α is an essential enzyme mainly mediating Okazaki fragment synthesis during lagging strand replication. A specific point mutation in Schizosaccharomyces pombe polymerase α named swi7-1, abolishes imprinting required for mating-type switching. Here we investigate whether this mutation confers any genome-wide defects. We show that the swi7-1 mutation renders cells hypersensitive to the DNA damaging agents methyl methansulfonate (MMS), hydroxyurea (HU) and UV and incapacitates activation of the intra-S checkpoint in response to DNA damage. In addition we show that, in the swi7-1 background, cells are characterized by an elevated level of repair foci and recombination, indicative of increased genetic instability. Furthermore, we detect novel Swi1-, -Swi3- and Pol α- dependent alkylation damage repair intermediates with mobility on 2D-gel that suggests presence of single-stranded regions. Genetic interaction studies showed that the flap endonuclease Fen1 works in the same pathway as Pol α in terms of alkylation damage response. Fen1 was also required for formation of alkylation- damage specific repair intermediates. We propose a model to explain how Pol α, Swi1, Swi3 and Fen1 might act together to detect and repair alkylation damage during S-phase. PMID:23071723

Nitrogen Dynamics Along a Headwater Stream Draining a Fen, Swamp, and Marsh in a Fractured Dolomite Watershed

Science.gov (United States)

Duval, T. P.; Waddington, J. M.

2009-05-01

Stream-wetland interaction has been shown to have a significant effect on nutrient cycling and downstream water quality. Additionally, connection to regional groundwater systems can dilute or enrich stream water with a number of dissolved constituents. This study demonstrates the resultant downstream change in dissolved nitrogen species as a hardwater stream emerges from a calcareous aquifer and traverses a calcareous fen, a cedar swamp, and a cattail marsh over two growing seasons, a very dry 2006 and a very wet 2007. Upon emergence at a number of groundwater seeps, the water contained appreciable nitrate levels averaging 2.72±0.42 mg NO3-N L-1, minimal organic nitrogen, and ammonium below detectable levels. Through the gently sloping calcareous fen, with a stream residence time of ~ 5 hours, NO3-N concentration decreases of 0.35 mg L-1 were observed. Concomitantly, stream recharge into the dolomite bedrock depressed stream discharge values significantly, further removing nitrate from the stream system. This resulted in the fen-bedrock system acting as an estimated net sink of 432 kg of NO3-N in the early summer of 2007, for example. In contrast, the hydrological-biogeochemical systems became decoupled through the swamp during the same period, where concentrations increased from 2.58±0.34 mg L-1 entering the swamp to 2.65±0.58 mg L-1 exiting, but streamflow decreased in general by 5 L s- 1. This resulted in the swamp, with its large depression storage, acting as a small net sink of nitrate (75 kg through the early summer), which would not be detected simply from concentration changes. The concentration-discharge relation realigned through the marsh, where significant groundwater entered the wetland, increasing both concentration and discharge, yielding a small export of 93 kg over the same time period. A series of tracer injections in each wetland type will be presented to compare the streamflow- concentration patterns with the measured nutrient spiralling

How a regional aquifer, a local aquifer and an oxbow lake impact on hydrological and biogeochemical processes in ariparian fen-meadow ecosystem

DEFF Research Database (Denmark)

Hoffmann, Carl Christian; Pedersen, Morten Lauge; Rasmussen, K. R.

2009-01-01

The groundwater flow pattern through a riparian fen-meadow was investigated by use of piezometer transects, soil survey, measurements of piezometric heads and measurements of hydraulic conductivity. Groundwater was sampled from piezometers and analysed for nitrate-N. Water balances and nitrate-N ...

La fibra óptica y el fenómeno no lineal mezcla de cuarta onda

Directory of Open Access Journals (Sweden)

Fabián Gómez López

2015-12-01

Full Text Available RESUMEN Para aprovechar de mejor manera el ancho de banda que tiene la fibra óptica, los sistemas de comunicaciones ópticos han tenido que aumentar la potencia de transmisión de las señales para poder transportar a grandes distancias la información. Debido a lo anterior, comienzan a producirse ciertos fenómenos ópticos no lineales como la mezcla de cuarta onda (Four Wave Mixing, FWM, que degradan la señal de información. En este documento se realiza un estado del arte de la fibra óptica y un estudio del fenómeno no lineal FWM, que se genera cuando dos o más señales ópticas se propagan en la fibra, lo cual conlleva a una mezcla de señales que puede generar nuevos componentes de interferencia de la señal óptica transmitida. ABSTRACT To make better use of the bandwidth that has the optical fiber, optical communications systems have had to increase the transmission power of signals to transport information over long distances. Because of this, certain nonlinear optical phenomena such as four wave mixing (Four Wave Mixing, FWM, which degrade the information signal begin to occur. Herein a state of the art of optical fiber and a study of the nonlinear FWM phenomenon, which is generated when two or more optical signals propagating in the fiber takes place, which leads to a mixture of signals that can generate new components interference of the transmitted optical signal.

Actividad antioxidante, compuestos fenólicos y ácido ascórbico de frutillas en dos sistemas de producción Antioxidant activity, phenolic compounds and ascorbic acid content in strawberries from two crop production systems

Directory of Open Access Journals (Sweden)

Rufino Fernando F Cantillano

2012-12-01

Full Text Available El objetivo de este trabajo fue determinar la influencia del sistema de producción y del período de almacenamiento de frutillas sobre la pérdida de masa, compuestos fenólicos totales, antocianinas totales, ácido ascórbico (vitamina C, actividad antioxidante y sus correlaciones. En este experimento fueron utilizadas frutillas 'Camarosa' y 'Camino Real' con madurez comercial, procedentes de cultivos en sistemas de producción orgánico y convencional, localizados en el municipio de Pelotas-RS. Los frutos fueron almacenados durante 0, 2, 5 y 8 días a 1ºC y 90-95% de HR. En general, el contenido de fenoles totales, de antocianinas totales y la actividad antioxidante aumentaron durante el almacenamiento refrigerado, mientras que los contenidos de ácido ascórbico y de masa fresca disminuyeron significativamente. Los contenidos de fenoles totales y de antocianinas totales presentaron correlación positiva con la actividad antioxidante, siendo la correlación con el contenido de ácido ascórbico negativa. Las frutillas producidas en sistema orgánico y conservadas durante cinco días, mostraron mayores valores de actividad antioxidante. Después de ocho días de almacenamiento a 1ºC, los frutos del sistema de producción orgánico presentaron menor degradación de antocianinas y de ácido ascórbico que los frutos del sistema de producción convencional.The aim of this study was to determine the influence of the crop production system and storage period on weight loss, total phenolic content, total anthocyanin content, ascorbic acid (vitamin C content, and antioxidant activity in strawberries, as well as their correlations. For this experiment, strawberry fruits of 'Camarosa' and 'Camino Real' at commercial maturity from both organic and conventional crop production systems located in Pelotas, Brazil, were used. The fruits were cold stored for 0, 2, 5, and 8 days at 1ºC and 90-95% RH. In general the total phenolic, total anthocyanin levels

Efectos ecológicos del fenómeno ENOS en Colombia

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Yesid Carvajal

2014-06-01

Full Text Available El fenómeno ENOS, tiene un sustancial efecto sobre las variaciones del clima a nivel mundial; por lo tanto, no sorprende que sus efectos tengan un impacto ecológico y socioeconómico fuerte, alterando la seguridad alimentaria de los países a nivel mundial. Ante este panorama, es comprensible que haya despertado el mayor interés mundial, no sólo en los especialistas en meteorología y oceanografía sino también entre biólogos, ecólogos, físicos, matemáticos, agrónomos, hidrólogos, economistas, sociólogos y planificadores, entre otros. En el presente documento, se muestra algunos de los principales efectos ecológicos en Colombia durante las fases extremas cálida (El Niño y fría (La Niña, indicando que es una necesidad urgente, orientar la investigación en sus causas, consecuencias e impactos.

Ecoenzymatic stoichiometry and microbial processing of organic matter in northern bogs and fens reveals a common P-limitation between peatland types

Science.gov (United States)

Brian H. Hill; Colleen M. Elonen; Terri M. Jicha; Randall K. Kolka; LaRae L.P. Lehto; Stephen D. Sebestyen; Lindsey R. Seifert-Monson

2014-01-01

We compared carbon (C), nitrogen (N), and phosphorus (P) concentrations in atmospheric deposition, runoff, and soils with microbial respiration [dehydrogenase (DHA)] and ecoenzyme activity (EEA) in an ombrotrophic bog and a minerotrophic fen to investigate the environmental drivers of biogeochemical cycling in peatlands at the Marcell Experimental Forest in northern...

Degradação de xenobióticos por fungos filamentosos isolados de areia fenólica

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J. H. Silva

2000-09-01

Full Text Available Microrganismos foram isolados de areia fenólica resultante de atividades metalúrgicas, utilizando meio mínimo para fungos e pentaclorofenol (PCF como única fonte de carbono. Após quatro repiques sucessivos em intervalos de 15 dias de incubação, as culturas foram plaqueadas em meio de Martin. Três gêneros de fungos foram isolados e identificados como Acremonium sp., Paecilomyces sp. e Penicillium sp. Estes foram testados para degradar os corantes índigo e RBBR (Azul Brilhante de Remazol - R e o organoclorado PCF. A descoloração do índigo foi de 99%, para Paecilomyces e Penicillium, e de 74%, para Acremonium, e a de RBBR foi de 16%, para Penicillium; 14%, para Acremonium, e 5%, para Paecilomyces. Usando azul de bromotimol como indicador de degradação de PCF, foram obtidos 24% de descoloração para Acremonium; 22%, para Penicillium, e 17%, para Paecilomyces Utilizando cromatografia gasosa, detectou-se degradação de PCF de 69%, para Penicillium; 65%, para Paecilomyces, e 40% para Acremonium, respectivamente. Os resultados mostraram que foi possível isolar microrganismos de uma areia de fundição, altamente contaminada com fenóis, e os fungos isolados foram capazes de degradar PCF e outros xenobióticos testados.

El Quijote y el fenómeno del quijotismo (Don Quixote and Quixotism Phenomenon

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Jesús Ruiz Fernández

2013-12-01

Full Text Available Resumen: Estudia el presente artículo el fenómeno del quijotismo, ingrediente de la razón, y, por tanto, del comportamiento humano. Pero distingue entre el error del quijotismo estático y el sano proceder del dinámico. Para ello se vale del concepto de razón vital de Ortega y Gasset, así como del Quijote. Con respecto al primero, amplía la utilización que de la magna obra podía haber hecho y no hizo el ilustre filósofo. Y sobre el segundo, destaca sus insuficiencias de contenido, por no haber alcanzado el quijotismo dinámico, es decir, porque, queriendo criticar el idealismo desmedido del caballero manchego, termina por proponer otro quijote. De cualquier forma, el artículo señala cómo el irónico fenómeno del quijotismo no es un juego, para lo cual discute ciertas interpretaciones recientes del Quijote.Abstract: This article studies Quixotism phenomenon, ingredient of vital reason, and, consequently, of human behaviour. However, it distinguishes between the mistake of static quixotism and the right conduct of the dynamic one. In order to do so, it makes use of Ortega y Gasset's concept of Vital Reason, and Don Quixote’s as well. Concerning the first one, it highlights the insufficiency of its content since it has not fulfilled the dynamic quixotism, that is to say, because, with the intention to criticize La Mancha’s Knight’s excessive idealism, it ends up proposing other quixotic person. Anyway, this article points out how the ironic quixotism phenomenon is not a game, for which reason it discusses certain Don Quixote’s recent interpretations.

Avaliação do teor de antioxidantes, flavonoides e compostos fenólicos em preparações condimentares

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G.M. MENDES

2015-06-01

Full Text Available RESUMO:Plantas condimentares são amplamente utilizadas na culinária como alimento funcional. Pacientes hipertensos, que retiram o sal de cozinha (NaCl de sua alimentação, relatam que os alimentos "perdem" o sabor. Visando alternativas para substituir o sal e melhorar a palatabilidade das preparações alimentares de pacientes hipertensos, o objetivo deste estudo foi desenvolver temperos à base de plantas medicinais e analisar os teores de compostos fenólicos, flavonoides e atividade antioxidante destes. Plantas (coentro, salsa, orégano, alecrim, manjericão, alho, cebola cultivadas organicamente em Viçosa (MG foram processadas e os temperos foram desenvolvidos a partir de combinação destas espécies, de acordo com teste aceitabilidade sensorial afetivo por meio de escala hedônica. Foram definidos três temperos, dos quais foram feitos extratos metanólicos por remaceração até esgotamento. Nas dosagens utilizou-se DPPH na avaliação da atividade antioxidante; reagente de Folin-Ciocalteu para compostos fenólicos e vanilina clorídrica para flavonoides. As análises foram feitas com quatro repetições e os resultados submetidos à análise de variância e teste de média a 5% de significância. Na aceitação subjetiva dos temperos a nota média foi 7,07±1,09 e 8,0±0,93 na ação afetiva como alimento. O teor mais elevado de compostos fenólicos foi no tempero 2 (alho, salsa e manjericão (55,04±4,307 mg/mL, a maior ação antioxidante foi no tempero 1 (alho, cebola, coentro e orégano nos tempos 0 (48,72% e 30 minutos (78,37%. Os teores de flavonoides foram semelhantes nos 3 temperos. Todos os temperos tiveram boa aceitação por pacientes hipertensos e mostraram-se promissores na substituição dos condimentos convencionais.

Relación entre la planificación urbana y fenómeno de variabilidad climática en la costa caribe colombiana: estudio de caso: fenómeno de la niña en Cartagena 2001-2011

OpenAIRE

Covelli Garrido, Cristina Isabel

2015-01-01

El presente trabajo de grado tiene como fin evidenciar las relaciones entre los instrumentos de planificación y los impactos de fenómenos de variabilidad climática en territorios vulnerables. Se analizan los factores de vulnerabilidad, amenaza y riesgo en la Ciénaga de la Virgen en Cartagena así como algunas de las decisiones de planificación tomadas durante el periodo estudiado (2001-2011) para finalmente identificar aquellos retos que deben ser tenidos en cuenta por futuros ejercicios de pl...

Correlações entre compostos fenólicos e atividade antioxidante em casca e polpa de variedades de uva de mesa

Directory of Open Access Journals (Sweden)

Angela Vacaro de Souza

2018-02-01

Full Text Available Resumo Uvas são consideradas excelentes fontes de compostos fenólicos, quando comparadas a outros vegetais; porém, a grande diversidade entre as cultivares resulta em frutos com diferentes características, tanto de sabor quanto de coloração, o que, certamente, está associado com o conteúdo e o perfil de compostos polifenólicos. Cascas e polpas de amostras de uva no ponto de consumo − tipos “Itália”, “Brasil”, “Rubi”, “Thompson” e “Niágara Rosada” − da região de Campinas e Jundiaí, Estado de São Paulo, foram estudadas com o objetivo de avaliar a atividade antioxidante, a atividade enzimática da peroxidase e da polifenoloxidase e os teores de compostos fenólicos e de ácido ascórbico. A fim de verificar as correlações entre as cascas e polpas das variedades e as características, utilizou-se a Correlação de Pearson, a distância generalizada de Mahalanobis (D2 e, por fim, o agrupamento das diferentes respostas através da análise multivariada. Verificou-se que as cascas das uvas analisadas apresentaram correlação positiva com o conteúdo de compostos fenólicos, a atividade da enzima polifenoloxidase e com o teor de ácido ascórbico, exceto a cultivar “Niágara Rosada”, a qual mostrou maiores valores para estas avaliações. Não houve correlação entre o índice de atividade antioxidante com as demais análises realizadas. As cascas se mostraram uma ótima fonte para estes compostos.

Stream characteristics and their implications for the protection of riparian fens and meadows

DEFF Research Database (Denmark)

Baattrup-Pedersen, A.; Larsen, S.E.; Andersen, Peter Mejlhede

2011-01-01

the influence of stream size, morphology and chemical water characteristics for the distribution of water-dependent terrestrial habitat types, i.e. alkaline fens, periodically inundated meadows and meadows in riparian areas in Denmark using an extensive data set covering a total of 254 stream reaches. A species......1. Running waters, including associated riparian areas, are embraced by international legal frameworks outlining targets for the preservation, protection and improvement of the quality of the environment. Interactions between stream and river processes and riparian habitats have not received much...... attention in the management of stream ecosystems, and integrated measures that consider both the ecological status of streams and rivers (sensu EU Water Framework Directive, WFD) and the conservation status of riparian habitats and species (sensu EU Habitats Directive, HD) are rare. 2. Here, we analysed...

Diversity of Picoeukaryotes at an Oligotrophic Site off the Northern Red Sea Coast

KAUST Repository

Espinosa, Francisco Jose Acosta

2012-05-01

Picoeukaryotes are protist 3 µm belonging to a wide diversity of taxonomic groups, and they are an important constituent of the ocean microbiota, performing essential ecological roles in marine trophic chains and in nutrient and carbon budgets. Despite this, the true extent of their diversity is currently unknown, and in the last decade molecular surveys have uncovered a substantial number of previously unknown groups from all taxonomic levels. No studies on this group have been done so far on the Red Sea, a unique marine environment characterized by oligotrophic conditions and high irradiance, salinity and water temperature. We sampled the surface waters of a site near the northern Red Sea coast, and analyzed the picoeukaryotic diversity through the construction of PCR clone libraries using the 18S ribosomal gene. The community captured by our library is dominated by three main groups, the alveolates (32%), chlorophytes (32%) and Stramenopiles (20.55%). Members of Radiolaria, Cercozoans and Haptophyta were also found, although in low abundances. Photosynthetic organisms are especially diverse and abundant in the sample, with heterotrophic organism mostly composed by the mostly parasitic novel alveolates and bacterivorous stramenopiles. Novel clades were detected among the Novel Alveolates- II and the photosynthetic stramenopiles taxa, which suggests that they may be part of a number of groups unique to the basin and adapted to the high salinity and temperature conditions. This is the first study done on the Red Sea focusing on the diversity of the complete picoeukaryotic fraction, and provides a stepping stone in the characterization of the picoeukaryotic component of the microbial diversity of the basin.

Degradação de xenobióticos por fungos filamentosos isolados de areia fenólica

OpenAIRE

J. H. Silva; R. T. R. Monteiro

2000-01-01

Microrganismos foram isolados de areia fenólica resultante de atividades metalúrgicas, utilizando meio mínimo para fungos e pentaclorofenol (PCF) como única fonte de carbono. Após quatro repiques sucessivos em intervalos de 15 dias de incubação, as culturas foram plaqueadas em meio de Martin. Três gêneros de fungos foram isolados e identificados como Acremonium sp., Paecilomyces sp. e Penicillium sp. Estes foram testados para degradar os corantes índigo e RBBR (Azul Brilhante de Remazol - R) ...

Fatty acid-oxidizing consortia along a nutrient gradient in the Florida Everglades.

Science.gov (United States)

Chauhan, Ashvini; Ogram, Andrew

2006-04-01

The Florida Everglades is one of the largest freshwater marshes in North America and has been subject to eutrophication for decades. A gradient in P concentrations extends for several kilometers into the interior of the northern regions of the marsh, and the structure and function of soil microbial communities vary along the gradient. In this study, stable isotope probing was employed to investigate the fate of carbon from the fermentation products propionate and butyrate in soils from three sites along the nutrient gradient. For propionate microcosms, 16S rRNA gene clone libraries from eutrophic and transition sites were dominated by sequences related to previously described propionate oxidizers, such as Pelotomaculum spp. and Syntrophobacter spp. Significant representation was also observed for sequences related to Smithella propionica, which dismutates propionate to butyrate. Sequences of dominant phylotypes from oligotrophic samples did not cluster with known syntrophs but with sulfate-reducing prokaryotes (SRP) and Pelobacter spp. In butyrate microcosms, sequences clustering with Syntrophospora spp. and Syntrophomonas spp. dominated eutrophic microcosms, and sequences related to Pelospora dominated the transition microcosm. Sequences related to Pelospora spp. and SRP dominated clone libraries from oligotrophic microcosms. Sequences from diverse bacterial phyla and primary fermenters were also present in most libraries. Archaeal sequences from eutrophic microcosms included sequences characteristic of Methanomicrobiaceae, Methanospirillaceae, and Methanosaetaceae. Oligotrophic microcosms were dominated by acetotrophs, including sequences related to Methanosarcina, suggesting accumulation of acetate.

Informação: fenômeno e objeto de estudo da sociedade contemporânea

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Nair Yumiko Kobashi

Full Text Available O estudo da informação assume importância primordial na cultura contem-porânea, sendo tema desenvolvido por várias áreas do conhecimento. Cada disciplina deve, no entanto, identificar na informação o seu objeto específico, para que uma atividade compreensiva sobre o assunto substitua a explicação mecânica e funcionalista, largamente difundida, que não raro introduziu mais dúvidas e imprecisões do que soluções. É objetivo deste artigo discutir tanto o papel da Ciência da Informação no contexto das disciplinas que estão se constituindo, quanto a sua relevância sócio-política e econômica. Enfatiza-se a importância da elaboração conceitual para o entendimento do seu objeto e para a proposição de alternativas compreensivas do fenômeno. Conclui-se que a compreensão não se dá na amplitude do fenômeno geral, que está presente em todos os contextos disciplinares; ao contrário, ela requer a delimitação do contexto específico no qual a informação está sendo vista como valor e produtora de valor. A partir daí, os traços simplificados e fragmentados que a caracterizam serão consecutivamente analisados e substituídos através de uma abordagem que considere a complexidade da informação.

Jogos de Empresas: Abordagens ao Fenômeno, Perspectivas Teóricas e Metodológicas

Directory of Open Access Journals (Sweden)

Valdete de Oliveira Mrtvi

2017-01-01

Full Text Available Os jogos de empresas, além de utilizados no processo de ensino, também são explorados como ferramentas de pesquisa, conforme Gentry, Tice, Robertson e Gentry (1984. Este estudo, de natureza qualitativa e quantitativa, descritivo quanto aos objetivos, e caracterizado como revisão integrativa no tocante ao método, trata do seguinte problema de pesquisa: Qual o perfil da pesquisa acadêmica brasileira sobre jogos de empresas considerando a abordagem ao fenômeno e as perspectivas teóricas e metodológicas? Foram analisados 226 artigos extraídos de periódicos online, do indexador Spell e anais de eventos. Como resultado, é proposta uma tipologia para classificação das pesquisas em jogos de empresas, considerando a abordagem ao fenômeno de pesquisa e os eixos temáticos. Constatou-se a predominância de estudos que têm as simulações como objeto de pesquisa - SCOPE (77,9% -, enquanto 22,1% utilizam os jogos de empresas como ambiente de pesquisa - SCAPE. Verificou-se que 38,5% dos estudos não mencionam quaisquer das classificações metodológicas analisadas. Discute-se algumas fragilidades metodológicas identificadas nas pesquisas da área. Apesar de as classificações não serem determinantes para a qualidade de um estudo, representam importante indicador da consistência do processo de reflexão e da coesão da investigação.

Desarrollo de técnicas de extracción y análisis de antocianinas y compuestos fenólicos en Jaboticaba (Myrciaria Cauliflora)

OpenAIRE

Mera Morillo, Celia

2015-01-01

Desarrollo de técnicas de extracción mediante ultrasonidos y mediante fluidos presurizados para así, obtener las condiciones óptimas de extracción de las antocianinas mayoritarias y compuestos fenólicos totales presentes en la jaboticaba

Ortaokul 5. ve 6. Sınıf Fen Bilimleri Öğretim Programının Kazanım ve İçerik İlişkisinin Değerlendirilmesi

OpenAIRE

Ocak, Gürbüz; Kutlu Kalender, M. Damla

2018-01-01

Bu çalışma Milli Eğitim Bakanlığı tarafından basılmış 5. ve 6. Sınıf Fen Bilimleri ders kitaplarındaki içeriğin, ortaokul 5. ve 6. Sınıf Fen Bilimleri dersi öğretim programındaki kazanımlara uygunluk düzeyini değerlendirmeyi amaçlamıştır. Öncelikle 2015-2016 eğitim öğretim yılı 5. ve 6.sınıf öğretim programındaki kazanımlarla 5.ve 6. sınıf fen bilimleri ders kitaplarındaki içerikler incelenmiştir. Değerlendirme için ölçme aracı olarak kazanım-içerik değerlendirme rubriği hazırlanmıştır. Geliş...

Determinação de compostos fenólicos em amostras comerciais de chás verde e preto - Camellia sinensis (L. Kuntze, Theaceae - DOI: 10.4025/actascihealthsci.v31i2.6233

Directory of Open Access Journals (Sweden)

Maria Eugênia Costa

2009-09-01

Full Text Available O chá de Camellia sinensis é rico em compostos fenólicos antioxidantes, responsáveis por efeitos benéficos à saúde humana. Neste trabalho, foram realizadas as determinações da concentração de fenóis totais e flavonoides de sete amostras comerciais dos chás preto e verde. Os teores de fenóis totais variaram de 4,80 a 26,60 mg de pirogalol g-1 de amostra e os de flavonoides, de 0,46 a 1,10 mg de quercetina g-1 de amostra. A análise anatômica do conteúdo das amostras permitiu caracterizar a autenticidade dos produtos, observando-se os marcadores anatômicos típicos da espécie (estômatos anomocíticos, tricomas tectores unicelulares, mesofilo dorsiventral, drusas de oxalato de cálcio e esclereides.

Sentimentos do adolescente relacionados ao fenômeno BULLYING: possibilidades para a Assistência de Enfermagem nesse contexto

Directory of Open Access Journals (Sweden)

Agnes Schutz de Oliveira

2006-04-01

Full Text Available O bullying é um fenômeno devastador podendo vir a afetar a auto-estima e a saúde mental dos adolescentes. Geralmente ocorre quando o adolescente é mais suscetível ou vulnerável às agressões verbais ou morais que lhes causam angústia e dor, principalmente quando ocorrido em ambiente escolar traduzindo-se como uma forma de exclusão social. Pode desencadear alguns problemas de saúde tais como a anorexia, bulimia, depressão, ansiedade e até mesmo o suicídio. A enfermagem, pautada com princípios de prevenir agravos de diversos males, preocupa-se também com esta intercorrência traumática na adolescência. O objetivo deste estudo foi identificar sentimentos que possam estar relacionados com o bullying em adolescentes alunos de 5ª a 8ª séries. Tratou-se de uma pesquisa descritiva de abordagem qualitativa, realizada em uma escola de segmento religioso conveniada com o estado. A coleta de dados ocorreu auxiliada por entrevistas gravadas, posteriormente transcritas e submetidas à análise temática. Os resultados mostraram que os sentimentos relacionados ao fenômeno são múltiplos e variados, sendo categorizados como aspectos de caráter positivo, aspectos de caráter negativo e aspectos de caráter necessário.

BOREAS TGB-6 Soil Methane Oxidation and Production from NSA BP and Fen Sites

Science.gov (United States)

Deck, Bruce; Wahlen, Martin; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-6) team collected soil methane measurements at several sites in the Southern Study Area (SSA) and Northern Study Area (NSA). This data set contains soil methane consumption (bacterial CH4 oxidation) and associated C-13 fractionation effects in samples that were collected at various sites in 1994 and 1996 from enclosures (chambers). Methane C-13 data in soil gas samples from the NSA Young Jack Pine (YJP) and Old Jack Pine (OJP) sites for 1994 and 1996 are also given. Additional data on the isotopic composition of methane (carbon and hydrogen isotopes) produced in the NSA beaver ponds and fen bog in 1993 and 1994 are given as well. The data are stored in tabular ASCII files.

Efecto antifúngico de extractos fenólicos y de carotenoides de chiltepín (Capsicum annum var. glabriusculum en Alternaria alternata y Fusarium oxysporum

Directory of Open Access Journals (Sweden)

Alfonso Rodriguez-Maturino

2015-03-01

Full Text Available En el presente estudio se evaluó el efecto de extractos fenólicos y de carotenoides procedentes de frutos de chiltepín sobre el crecimiento micelial y la germinación de conidios de Alternaria alternata y Fusarium oxysporum, 2 importantes hongos causantes de podredumbres en frutas y hortalizas. Los extractos fenólicos presentaron una inhibición en el crecimiento micelial de A. alternata del 38,46 %, y redujeron significativamente la germinación de conidios al quinto día después del tratamiento al 92 % en relación al control. No se observaron cambios significativos en el crecimiento micelial de F. oxysporum, pero sí se redujo significativamente al 85 % en relación al control, el número de conidios germinados a los 5 días de tratamiento. Los extractos de carotenoides mostraron una inhibición del 38,5 % en el crecimiento micelial y del 85,3 % en la germinación de conidios de A. alternata, 5 días después del tratamiento. Frente a F. oxysporum, dichos extractos presentaron menor inhibición del crecimiento micelial (20,3 %, mientras que hubo una mayor inhibición en la germinación de conidios (96 %. Los extractos fenólicos y de carotenoides de chiltepín pueden ser una alternativa promisoria de importancia agrícola como fungicidas naturales.

Seasonal variation of the protozooplanktonic community in a tropical oligotrophic environment (Ilha Solteira reservoir, Brazil).

Science.gov (United States)

Mansano, A S; Hisatugo, K F; Leite, M A; Luzia, A P; Regali-Seleghim, M H

2013-05-01

The seasonal variation of the protozooplanktonic community (ciliates and testate amoebae) was studied in a tropical oligotrophic reservoir in Brazil, which was under the influence of two contrasting climatic seasons (rainy/warm and dry/cold). The aim of this study was to evaluate the effect of these climatic changes on physical, chemical and biological variables in the dynamic of this community. The highest mean density of total protozoans occurred in the rainy/warm season (5683.2 ind L-1), while the lowest was in the dry/cold (2016.0 ind L-1). Considering the seasonal variations, the protozoan groups that are truly planktonic, such as the oligotrichs (Spirotrichea), predominated in the dry season, whereas during the rainy season, due to the material input and resuspension of sediment, sessile protozoans of the Peritrichia group were the most important ones. The dominant protozoans were Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. and Halteria grandinella. The highest densities of H. grandinella were associated with more oxygenated and transparent water conditions, while the highest densities of C. annulata occurred in sites with high turbidity, pH and trophic state index (TSI). The study demonstrated that density and composition of protozooplanktonic species and groups of the reservoir suffered seasonal variation due to the environmental variables (mainly temperature, turbidity, water transparency, dissolved oxygen and TSI) and the biological variables (e.g. morphological characteristics, eating habits and escape strategies from predation of the species).

Seasonal variation of limnological features and trophic state index of two oligotrophic reservoirs of southeast Brazil.

Science.gov (United States)

Oliveira, S A; Bicudo, C E M

2017-01-01

Limnological features of two reservoirs were studied in dry (August 2013) and rainy (January 2014) periods to evaluate the water quality that supply the city of Guarulhos, southeast Brazil. Water samples were collected in three depths and the following characteristics were measured: alkalinity, dissolved O2, free and total CO2, HCO3, soluble reactive silica, dissolved and total nitrogen and phosphorus, and chlorophyll-a. Water transparency was also measured and temperature, pH and electric conductivity profiles were obtained. Great seasonal and low spatial variability of the water characteristics occurred in the reservoirs. High values of water transparency, free CO2 availability, and low of pH, soluble reactive silica and total and dissolved nutrients values were recorded at the dry period, and different conditions were found at the rainy season. The two reservoirs were characterized by low nutrients, chlorophyll-a and turbidity, and high transparency, these features being typical of oligotrophic systems. The two reservoirs still remain under low anthropogenic impact conditions, and are presently considered reference systems for the SPMR, São Paulo Metropolitan Region. The need for actions that will reduce the input of nutrients from the neighboring cities and the main tributaries of the hydrographic basin is emphasized to maintain the ecological quality of the reservoirs and their reference conditions among the SPRM reservoirs.

Biochemical analyses indicate that binding and cleavage specificities define the ordered processing of human Okazaki fragments by Dna2 and FEN1.

Science.gov (United States)

Gloor, Jason W; Balakrishnan, Lata; Campbell, Judith L; Bambara, Robert A

2012-08-01

In eukaryotic Okazaki fragment processing, the RNA primer is displaced into a single-stranded flap prior to removal. Evidence suggests that some flaps become long before they are cleaved, and that this cleavage involves the sequential action of two nucleases. Strand displacement characteristics of the polymerase show that a short gap precedes the flap during synthesis. Using biochemical techniques, binding and cleavage assays presented here indicate that when the flap is ∼ 30 nt long the nuclease Dna2 can bind with high affinity to the flap and downstream double strand and begin cleavage. When the polymerase idles or dissociates the Dna2 can reorient for additional contacts with the upstream primer region, allowing the nuclease to remain stably bound as the flap is further shortened. The DNA can then equilibrate to a double flap that can bind Dna2 and flap endonuclease (FEN1) simultaneously. When Dna2 shortens the flap even more, FEN1 can displace the Dna2 and cleave at the flap base to make a nick for ligation.

Fenómeno el niño y desastres naturales: intervenciones en salud pública para la preparación y respuesta

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Gisely Hijar

Full Text Available RESUMEN El presente artículo realiza una revisión de las intervenciones en salud pública para la preparación y respuesta ante desastres naturales en el contexto del fenómeno El Niño (FEN a partir de revisiones sistemáticas y una revisión de revisiones con énfasis en las enfermedades transmitidas por vectores, transmitidas por el agua, malnutrición, estrés térmico, sequías, enfermedades asociadas a inundaciones, problemas de salud mental, vulnerabilidad de la infraestructura física de los servicios de salud, así como de las políticas a largo plazo orientadas a proteger a la población en estos casos. Se identificaron intervenciones ambientales, como el control de vectores, quimioprofilaxis, vacunación y tratamiento intradomiciliario de agua. Si bien estos hallazgos se basan principalmente en revisiones sistemáticas, es necesario evaluar el beneficio de estas intervenciones en la población, de acuerdo con la realidad de cada región.

The influence of nanoflagellates on the spatial variety of picoplankton and the carbon flow of the microbial food web in the oligotrophic subtropical pelagic continental shelf ecosystem

Science.gov (United States)

Chiang, Kuo-Ping; Tsai, An-Yi; Tsai, Pei-Jung; Gong, Gwo-Ching; Huang, Bang-Qin; Tsai, Sheng-Fang

2014-06-01

To investigate the mechanism of the spatial dynamics of picoplankton community (bacteria and Synechococcus spp.) and to estimate the carbon flux of the microbial food web in the oligotrophic Taiwan Warm Current Water of the subtropical marine pelagic ecosystem, we conducted size-fractionation experiments during five cruises by the R/V Ocean Research II during the summers of 2010 and 2011 in the southern East China Sea. We carried out culture experiments using surface water, which according to a temperature-salinity (T-S) diagram, is characterized as oligotrophic Taiwan Current Warm Water. We found a negative correlation between bacteria growth rate and temperature, and another negative correlation between nitrate and temperature indicating that the active growth of heterotrophic bacteria might be induced by nutrients lifted from a deep layer by cold upwelling water. This finding suggests that the area we studied was a bottom-up control pelagic ecosystem. Upwelling brings nutrient-rich water to the euphotic zone and promotes bacterial growth, resulting in increased picoplankton biomass, which increases the consumption rate of nanoflagellates. The net growth rate (growth rate-grazing rate) becomes negative when the densities of bacteria and Synechococcus spp. are lower than the threshold values. The interaction between growth and grazing will limit the abundance of bacteria (105-106 cells ml-1) and Synechococcus spp. (104-105 cells ml-1) within a narrow range. Meanwhile, 61% of bacteria production and 54% of Synechococcus spp. production are transported to a higher trophic level (nanoflagellate), though the cascade effect might cause an underestimation of both percentages of transported carbon. Based on the successive size-fractionation experiments, we estimated that the predation values were underestimated and that the diet of nanoflagellates is composed of 64% bacteria and 36% Synechococcus spp.

Fen-Phen Litigation Against American Home Products Corporation: The Widespread Use of Fenfluramine (Pondimin) and Dexfenfluramine (Redux) for Weight Loss, The Health Problems Associated with Those Drugs, the Resulting Litigation Against American Home Prod

OpenAIRE

Tragos, Camille N.

2000-01-01

The fen-phen affair has spawned thousands of lawsuits and a multitude of scientific studies concerning valvular heart disease. It has also led to a lively debate over off-label prescriptions, medical monitoring, and class actions. The proposed Settlement Agreement, while an attempt to put an end to the valvular litigation, will not be the end of the fen-phen affair. The Settlement Agreement has been widely criticized and plaintiffs' lawyers have indicated that there will be a large number of ...

Microbial ecology of acid strip mine lakes in southern Indiana

International Nuclear Information System (INIS)

Gyure, R.A.

1986-01-01

In this study, the author examined the limnology and microbial ecology of two acid strip mine lakes in the Greene-Sullivan State Forest near Dugger, Indiana. Reservoir 29 is a larger lake (225 ha) with water column pH of 2.7 and sediment pH of 3.8. Lake B, a smaller (20 ha) lake to the south of Reservoir 29, also has an acidic water column (pH 3.4) but more neutral sediments (pH 6.2). Both have very high sulfate concentrations: 20-30 mM in the water column and as high as 100 mM in the hypolimnion of Lake B. Low allochthonous carbon and nutrient input characterize these lakes as oligotrophic, although algal biomass is higher than would be expected for this trophic status. In both lakes, algal populations are not diverse, with a few species of single-celled Chlorophyta and euglenoids dominating. Algal biomass is concentrated in a thin 10 cm layer at the hypolimnion/metalimnion interface, although light intensity at this depth is low and severely limits productivity. Bacterial activity based on 14 C-glucose incorporation is highest in the hypolimnion of both lakes, and sulfate-reduction is a dominant process in the sediments. Rates of sulfate-reduction compare with those in other freshwater environments, but are not as high as rates measured in high sulfate systems like saltmarsh and marine sediments

FiveS rRNA sequences and fatty acid profiles of colourless sulfur-oxidising bacteria

Digital Repository Service at National Institute of Oceanography (India)

LokaBharathi, P.A.; Ortiz-conde, B.A.; Nair, S.; Chandramohan, D.; Colwell, R.R.

Colourless sulfur-oxidising bacteria have been encountered extensively in the oxygen minimum layers of the Arabian Sea. These oligotrophs have been known to mediate nitrogen cycle reductively even under autotrophic conditions. Some...

Effects of peat-winning on the water environment at a sedge fen ecosystem

International Nuclear Information System (INIS)

Lundin, L.

1997-06-01

Peatlands are used in agriculture and forestry for vegetational growth and in peat-winning for soil improvement, horticulture production and as fuel. A prerequisite in peatland use is drainage, with influences on water conditions in the peatland and in its surroundings. Environmental effects from such peatland use have been investigated at a sedge fen in central Sweden. Groundwater, runoff, water chemistry and streamwater biology were studied during almost 14 years. This period started with a virgin undrained peatland, later being drained for forest production and after a period of seven years intensively drained for peat-winning and with peat harvesting going on for another seven year period with hydrological investigations. Results show a lowered groundwater level, increased runoff and both higher concentrations of most elements and higher leaching from the drained peatland. Biomass and number of individuals of the benthic fauna in streamwater also increased. 7 refs

Estudo do comportamento fotofísico de prepregs de fibra de vidro e resina fenólica.

OpenAIRE

Rogério da Silva Rosa

2007-01-01

O objetivo desse trabalho é a aplicação da Espectroscopia de Luminescência em modo estacionário para o estudo do processo de cura de pré-impregnados (prepregs) de fibra de vidro e resina fenólica, tratadas termicamente em três diferentes temperaturas 90, 120 e 150 C. O processo de cura dos prepregs também foi monitorado por Espectroscopia de absorção na região do Infravermelho com transformada de Fourier (FT-IR). Os espectros de luminescência dos prepregs mostram mudanças significativas atrib...

Extratos biotransformados de fenólicos de cítricos e atividade anti-inflamatória "in vitro"

OpenAIRE

Tais Moala

2016-01-01

Resumo: O processo inflamatório é um mecanismo de defesa desenvolvido pelo organismo com o objetivo de combater infecções (originadas por vírus, bactérias ou outros patógenos) e também injúrias (cortes ou queimaduras). Os compostos fenólicos são amplamente distribuídos em muitos produtos derivados de plantas e apresentam uma gama de propriedades benéficas para a saúde humana, como atividade antioxidante e anti-inflamatória. A atividade antioxidante desses compostos está relacionada com a pres...

El fenómeno del apoyo al aprendizaje fuera de la escuela visto a través de un análisis comparado

Directory of Open Access Journals (Sweden)

Alexandre Ventura

2006-01-01

Full Text Available La prácticas de apoyo al aprendizaje fuera de la escuela, que se analizan en este artículo, han merecido nuestra atención por diversas razones: 1 el hecho de que son prácticamente un fenómeno mundial, a pesar de los sistemas educativos difieran de un país a otro; 2 el hecho de que las repercusiones de las explicaciones sobre los resultados escolares puedan llevar a una reubicación de los principios de equidad e igualdad de oportunidades; 3 la constatación de que los costes financieros soportados por las familias de los alumnos, por un lado, y el número creciente de “explicadores” disponibles (trabajando a tiempo parcial o en jornada completa, por otro, confieren a esta actividad una importancia social y económica considerable. Este abordaje prima un análisis cualitativo del fenómeno de las clases particulares, con el objetivo de conocer mejor algunas de sus formas: su ejercicio en exclusividad o como complemento del salario obtenido en el decurso de otra actividad; como iniciativa de base individual, característica de una actividad liberal; en el contexto de un centro/academia local; o en el contexto de un centro de estudios con franquicia, de dimensión nacional o multinacional. Al realizar un análisis comparado de este fenómeno, buscaremos mostrar como las explicaciones constituyen una actividad promovida de forma creciente en organizaciones (centros de explicaciones, sobre todo en los grandes centros urbanos. Estos centros de explicaciones están para suplementar o competir con las escuelas utilizando metodologías de sistematización o especialización.

Atributos privativos e musicais do fenômeno noturno

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Clovis Salgado Gontijo Oliveira Clovis Salgado Gontijo Oliveira

2015-11-01

Full Text Available Desde a sua análise como mero fenômeno, elaborada com pretensões de neutralidade, a noite é por nós concebida a partir de atributos predominantemente privativos. Estes se acentuam culturalmente na tradição ocidental, que tende a desvalorizá-los como signos de um vazio de ordem ontológica, epistemológica, ética e, até mesmo, estética. Associadas a uma esfera de negatividade, tais privações parecem impedir ou, pelo menos, dificultar o tratamento artístico da experiência noturna, sobretudo quando este pretende se realizar num modelo de arte em continuidade com uma proposta visual e iluminista. Tomando como base nossa tese de doutorado, intitulada XXX, pretendemos aqui analisar de que modo os atributos privativos referentes à noite não só dificultam a sua mímese quanto estão presentes, sob nova interpretação, em contextos que revalorizam positivamente a experiência noturna, potencializando-a, assim, como motivo. Dentre estes contextos, concederemos particular atenção à arte musical, que, coincidentemente, manifesta para o teórico e o ouvinte alguns dos mesmos atributos privativos identificados na análise primária do noturno. A fim de efetuar este estudo, recorreremos ao pensamento de Vladimir Jankélévitch, principal fundamentação teórica da tese cujo percurso será sintetizado neste artigo.

Fenômeno, estrutura, sintoma e clínica: a droga

Directory of Open Access Journals (Sweden)

Sonia Alberti

Full Text Available Partindo de uma leitura que se baseia em quatro autores brasileiros, este trabalho problematiza e verifica posições teóricas acerca do fenômeno toxicomaníaco e levanta a hipótese de que é possível, com o discurso do analista, em certo contexto e a partir de certas condições, apontar a toxicomania como equivalente ao sintoma no discurso da histérica, o que abre vias para a construção de uma clínica em que prevaleça a aposta no desejo do analista. Ao retomar as referências freudianas quanto à equivalência da droga com o discurso religioso e suas funções de entorpecimento, verificase uma possível sustentação metafórica, necessária para qualquer formação de sintoma. Por outro lado, ao retomar as referências de Lacan quanto ao discurso do capitalista como o discurso do mestre contemporâneo, a questão é de sustentar a possibilidade de a droga fazer obstáculo ao livre funcionamento do gozo do mestre nesse discurso.

Influence of harvest managements on biomass nutrient concentrations and removal rates of festulolium and tall fescue from a poorly drained nutrient-rich fen peatland

DEFF Research Database (Denmark)

Kandel, Tanka; Elsgaard, Lars; Lærke, Poul Erik

2017-01-01

This study was designed to show the effects of harvest time and frequency on biomass nutrient concentrations (total ash, N, P, K, Ca, Mg, Fe, Mn, Cu and Zn) as well as total nutrient removal potential by festulolium and tall fescue cultivated on a nutrient-rich fen peatland. The harvest managemen...

Herbaceous Peony (Paeonia lactiflora Pall. as an Alternative Source of Oleanolic and Ursolic Acids

Directory of Open Access Journals (Sweden)

Jun Tao

2011-01-01

Full Text Available Oleanolic acid (OA and ursolic acid (UA have been proven to possess many biological activities, and much attention is focused on the search for plants which are rich in OA and UA. In this report, the OA and UA accumulation characteristics were investigated in 47 cultivars of Chinese herbaceous peony (Paeonia lactiflora Pall. and were followed in three cultivars over different developmental stages as measured by high performance liquid chromatography (HPLC. OA and UA levels in leaves and stems demonstrated an overall upward trend from May 1 to September 15 except for UA in the leaves of “Hong Feng”. The maximum values of OA and UA in leaves of “Yangfei Chu Yu”, “Fen Zhu Pan” and “Hong Feng” were 852.98, 575.60, 290.48 μg/g FW and 924.94, 827.36, 432.67 μg/g FW, respectively. The maximum values of OA and UA in stems of “Yangfei Chu Yu”, “Fen Zhu Pan” and “Hong Feng” were 359.28, 90.49, 43.90 μg/g FW and 326.86, 82.25, 56.63 μg/g FW, respectively. OA and UA contents in leaves of 47 different herbaceous peony cultivars ranged from 66.73–618.12 and 36.23–665.14 μg/g FW, respectively, with average values of 171.62 and 227.57 μg/g FW, respectively. The results suggested that the aboveground parts of herbaceous peony may be used as an alternative source of OA and UA for medicinal purposes in addition to its ornamental purposes.

The synthesis of theo fen containing bile acids

International Nuclear Information System (INIS)

Kadirov, A.Kh.; Khaydarov, K.Kh.; Giyosov, A.Sh.

2000-01-01

In this chapter of book authors made conclusion that synthesized compounds (V-V III) have ability to dissolve gall-cholesterol stones. These compounds actually have this effect, but at the same time observe the increase of toxicity of these matters

Climate Warming as a Possible Trigger of Keystone Mussel Population Decline in Oligotrophic Rivers at the Continental Scale.

Science.gov (United States)

Bolotov, Ivan N; Makhrov, Alexander A; Gofarov, Mikhail Yu; Aksenova, Olga V; Aspholm, Paul E; Bespalaya, Yulia V; Kabakov, Mikhail B; Kolosova, Yulia S; Kondakov, Alexander V; Ofenböck, Thomas; Ostrovsky, Andrew N; Popov, Igor Yu; von Proschwitz, Ted; Rudzīte, Mudīte; Rudzītis, Māris; Sokolova, Svetlana E; Valovirta, Ilmari; Vikhrev, Ilya V; Vinarski, Maxim V; Zotin, Alexey A

2018-01-08

The effects of climate change on oligotrophic rivers and their communities are almost unknown, albeit these ecosystems are the primary habitat of the critically endangered freshwater pearl mussel and its host fishes, salmonids. The distribution and abundance of pearl mussels have drastically decreased throughout Europe over the last century, particularly within the southern part of the range, but causes of this wide-scale extinction process are unclear. Here we estimate the effects of climate change on pearl mussels based on historical and recent samples from 50 rivers and 6 countries across Europe. We found that the shell convexity may be considered an indicator of the thermal effects on pearl mussel populations under warming climate because it reflects shifts in summer temperatures and is significantly different in viable and declining populations. Spatial and temporal modeling of the relationship between shell convexity and population status show that global climate change could have accelerated the population decline of pearl mussels over the last 100 years through rapidly decreasing suitable distribution areas. Simulation predicts future warming-induced range reduction, particularly in southern regions. These results highlight the importance of large-scale studies of keystone species, which can underscore the hidden effects of climate warming on freshwater ecosystems.

El fenómeno MOOC y la universalidad de la cultura: las nuevas fronteras de la educación superior

Directory of Open Access Journals (Sweden)

Jose Gómez Galán

2014-01-01

Full Text Available Este artículo tiene como principal objetivo ofrecer una explicación a la rápida extensión del fenómeno MOOC –y su verdadera relevancia y posición en la Educación Superior– en el contexto de las dinámicas postmodernas de universalidad de la cultura, la comunicación y el conocimiento. Analiza, por medio de una metodología crítico-teórica y ex post facto, cómo los cursos MOOC representan una parte de la integración del mundo universitario en los complejos procesos de globalización propiciados por la revolución de las TIC, pero concluye que en modo alguno significan la última frontera de la Educación Superior. Como resultados más importantes se determina que contribuyen en cierta media a [1] una universalidad de la cultura, ubicándose dentro del fenómeno de la globalización y lo que hoy ésta representa, [2] la universalidad de la comunicación, en el seno de la convergencia tecno-mediática, [3] la universalidad del conocimiento, con el empleo de pedagogías y metodologías didácticas extendidas de modo global y, en definitiva, [4] la universalidad de la propia Educación Superior, partícipes de los procesos de homogenización de los modelos de estudios universitarios y de adaptación a las características de una sociedad en red. Pero no suponen un fenómeno de tal envergadura que lleve a una transformación radical de este nivel educativo. Ni siquiera ofrecen innovaciones pedagógicas y didácticas significativas en relación con lo ya aportado previa y paralelamente por otros procesos de e-learning. Significan tan sólo una de las muchas respuestas –en absoluto la única– a las nuevas necesidades sociales, en un contexto de formación para todos y durante toda la vida, lo que explica su eclosión.

Phase transformations in interstitial Fe-N alloys

Energy Technology Data Exchange (ETDEWEB)

Liapina, T.

2005-04-15

Nitriding is a prominent thermochemical heat-treatment procedure leading to various types of surface property improvements of the treated iron and steel. Many questions regarding even very basic properties of these compound layers and the relevant nitride phases are still open. Some of these open questions related with the behaviour of iron nitrides and, in particular, of iron nitride compound layers occurring below the usual process temperatures are addressed to in this thesis, as relevant e.g. for the cooling procedure after nitriding. The most important iron nitrides occurring in iron-nitride compound layers are the {gamma}'- and {epsilon}-phases in the Fe-N system. It is shown that for relatively low nitrogen contents of epsilon-iron nitrides (around Fe{sub 3}N) the cooling rate upon going down from an elevated annealing temperature to room temperature has a significant effect on the lattice parameters. X-ray and neutron diffraction analysis revealed that the lattice parameter values observed after fast cooling are affected by the higher degree of nitrogen disorder at elevated temperature, thus changing the c/a ratio. New relations between the lattice parameters of {epsilon}-iron nitrides and the nitrogen content are suggested for different types of cooling. The investigation by TEM of the decomposition upon annealing (633 K, 673 K) of initially homogeneous {epsilon}-Fe{sub 3}N powders revealed that the {gamma}'-formation occurs in only a few powder particles in a grain-like form. Moreover, diffraction line-profile analysis revealed N transport occurring from particle to particle, leading to inhomogeneities of N content in the epsilon-phase. It was shown that {gamma}'-iron nitride formation can occur by backwards growth of the existing {gamma}'-sublayer at the cost of the {epsilon}-sublayer increasing N concentration in the {epsilon}-layer. Another process, which may additionally occur in the compound layer upon annealing, is diffusion of N

Efeito da adição de compostos fenólicos sobre o crescimento de levedura etanologênica (Saccharomyces sp.) em meio sintético e em caldo de cana-de-açúcar

OpenAIRE

Silva, Marcus Vinicius Bastos da

2013-01-01

Este trabalho teve como principal objetivo avaliar o efeito da adição de compostos fenólicos no crescimento e a atividade fermentativa de levedura etanologênica (Saccharomyces sp.) em meio sintético (YPD) e em caldos de duas variedades de cana-de-açúcar. A maior parte destes compostos é solúvel em solventes orgânicos, tais como metanol, etanol, acetato de etila e entre outros. Para solubilização dos compostos fenólicos adicionados, foram avaliados estes três solventes, quanto a sua influência...

Effects of peat-winning on the water environment at a sedge fen ecosystem

International Nuclear Information System (INIS)

Lundin, L.

1996-03-01

Peatlands are used in agriculture and forestry for vegetational growth and in peat-winning for soil improvement, horticulture production and as fuel. A prerequisite in peatland use is drainage, with influences on water conditions in the peatland and its surroundings. Environmental effects from such peatland use have been investigated at a sedge fen in central Sweden. Groundwater, runoff, water chemistry and stream water biology were studied during almost 14 years. This period started with a virgin undrained peatland, later being drained for forest production and after a period of seven years intensively drained for peat-winning and with peat harvesting going on for another seven years period with hydrological investigations. Results show a lowered groundwater level, increased runoff and both higher concentrations of most elements and higher leaching from the drained peatland. Biomass and number of individuals of the benthic fauna in stream water also increased. 7 refs, 7 figs, 2 tabs

Fenótipo cintura hipertrigliceridêmica: associação com alterações metabólicas em adolescentes Hypertriglyceridemic waist phenotype: association with metabolic abnormalities in adolescents

Directory of Open Access Journals (Sweden)

Maria Ester P. da Conceição-Machado

2013-02-01

Full Text Available OBJETIVO: O presente estudo objetivou identificar a prevalência do fenótipo cintura hipertrigliceridêmica (CHT e avaliar sua associação com alterações metabólicas em adolescentes de baixa condição econômica. MÉTODO: Estudo transversal com amostra probabilística de 1.076 adolescentes entre 11 e 17 anos, de ambos os sexos, estudantes de escolas públicas. Os participantes foram submetidos à avaliação antropométrica (peso, altura e circunferência da cintura e à dosagem dos níveis de colesterol total, LDL-C, HDL-C, colesterol não HDL, triglicérides (TG e glicemia de jejum. Foram obtidas informações referentes às condições econômicas das famílias dos participantes.O fenótipo CHT foi definido pela presença simultânea da circunferência da cintura aumentada (> percentil 90 por idade e sexo e dos níveis séricos de triglicérides elevados (> 100 mg/dL. A análise de regressão logística foi utilizada para avaliação das associações de interesse. RESULTADOS: A prevalência do fenótipo CHT foi de 7,2% entre os adolescentes, sendo mais elevada na presença de obesidade (63,4%, do colesterol não HDL (16,6% e do LDL-C (13,7% altos. A análise bivariada indicou que, das variáveis metabólicas, apenas a glicemia não se associou ao fenótipo CHT. A análise multivariada, ajustada por sexo e idade, indicou que o fenótipo CHT se associou positivamente com o colesterol não HDL alto (odds ratio, 7,0; IC 95% 3,9-12,6 e com o HDL-C baixo (odds ratio, 2,7; IC 95%, 1,5-4,8. CONCLUSÕES: Este estudo mostrou que o fenótipo CHT se associou com um perfil lipídico aterogênico e sugere esse fenótipo como uma ferramenta de screening que pode ser utilizada para identificar adolescentes com alterações metabólicas.OBJECTIVE: This study aimed to identify the prevalence of hypertriglyceridemic waist (HTW phenotype, and to evaluate its association with metabolic abnormalities in adolescents of low socioeconomic status. METHOD: This

Methane Exchange in a Coastal Fen in the First Year after Flooding - A Systems Shift

Science.gov (United States)

Hahn, Juliane; Köhler, Stefan; Glatzel, Stephan; Jurasinski, Gerald

2015-01-01

Background Peatland restoration can have several objectives, for example re-establishing the natural habitat, supporting unique biodiversity attributes or re-initiating key biogeochemical processes, which can ultimately lead to a reduction in greenhouse gas (GHG) emissions. Every restoration measure, however, is itself a disturbance to the ecosystem. Methods Here, we examine an ecosystem shift in a coastal fen at the southern Baltic Sea which was rewetted by flooding. The analyses are based on one year of bi-weekly closed chamber measurements of methane fluxes gathered at spots located in different vegetation stands. During measurement campaigns, we recorded data on water levels, peat temperatures, and chemical properties of peat water. In addition we analyzed the first 20 cm of peat before and after flooding for dry bulk density (DBD), content of organic matter and total amounts of carbon (C), nitrogen (N), sulfur (S), and other nutrients. Results Rewetting turned the site from a summer dry fen into a shallow lake with water levels up to 0.60 m. We observed a substantial die-back of vegetation, especially in stands of sedges (Carex acutiformis Ehrh). Concentrations of total organic carbon and nitrogen in the peat water, as well as dry bulk density and concentrations of C, N and S in the peat increased. In the first year after rewetting, the average annual exchange of methane amounted to 0.26 ± 0.06 kg m-2. This is equivalent to a 190-times increase in methane compared to pre-flooding conditions. Highest methane fluxes occurred in sedge stands which suffered from the heaviest die-back. None of the recorded environmental variables showed consistent relationships with the amounts of methane exchanged. Conclusions Our results suggest that rewetting projects should be monitored not only with regard to vegetation development but also with respect to biogeochemical conditions. Further, high methane emissions that likely occur directly after rewetting by flooding should

Dispositivos móviles y el fenómeno del BYOD : Su impacto en la seguridad de las organizaciones

OpenAIRE

Venosa, Paula; Macia, Nicolás; Piazza Orlando, Carlos Damián; Pacheco Veliz, Sebastián Exequiel

2016-01-01

Las amenazas que atentan contra la seguridad de los dispositivos móviles: malware, robo, fuga de información, vulnerabilidades de software y phishing entre otras ponen en riesgo la seguridad personal de los usuarios y de los activos de información de las organizaciones en las que estos trabajan. Este artículo trata sobre el impacto del uso de los dispositivos móviles personales en las organizaciones lo cual se conoce como: Bring Your Own Device (BYOD). Este fenómeno constituye un campo de ...

Estudio del fenómeno Social Media en la pequeña empresa del sector TIC español

OpenAIRE

Río Onrubia, María Rebeca del

2014-01-01

En un mundo en el que cada vez son más las personas que utilizan Internet para llevar a cabo sus comunicaciones y relaciones, tanto a nivel personal como profesional, las Redes Sociales se han convertido en una herramienta, para muchos imprescindible, de interacción social. A lo largo de este proyecto se realizará un análisis exhaustivo de las características del ya conocido como Fenómeno Social Media, para posteriormente centrar toda la atención en las ventajas y desventajas de dicha acti...

La dictadura militar en Grecia (1967- 1974. ¿Cómo enfocar el fenómeno autoritario?

Directory of Open Access Journals (Sweden)

Georges D. CONTOGEORGIS

2010-02-01

Full Text Available RESUMEN: La Dictadura de los Coroneles es abordada como un fenómeno inherente al déficit democrático, no tanto de la sociedad griega, sino del sistema internacional. El hecho de que la Dictadura Griega se atribuya a valores geoestratégicos y al déficit democrático (p.e. la prohibición del acceso al poder de los partidos políticos no liberales de los líderes de la Guerra Fría está también en sintonía con la diferencia fundamental que lo distingue de las dictaduras de la Península Ibérica. Estas últimas están relacionadas con un mismo fenómeno anterior de la Europa anterior a la Segunda Guerra Mundial y como tales están clasificadas como una parte del proceso de transición que tuvo lugar en el Viejo Continente. Por el contrario, el fenómeno autoritario en el sistema político griego constituye un paréntesis porque la sociedad griega no experimentó la transición del feudalismo a la modernidad y su sistema político fue desde el comienzo (desde 1821 el primero entre los estados-nación con una base representativa asentada sobre el sufragio universal. Todo ello demuestra que las distinciones entre Norte y Sur, relativas a la democracia, están ideológicamente condicionadas y no derivan de conclusiones extraídas del desarrollo político de las sociedades. Palabras clave: Totalitarismo, Dictadura, Déficit democrático, Estado representativo, Guerra Fría, Protesta, Consenso político. ABSTRACT: The Dictatorship of the Colonels is approached as a phenomenon, which is inherent in the democratic deficit, not of Greek society, but of the international system. The fact that the Greek Dictatorship is attributed to geostrategic reasons and to the democratic deficit (e.g. the prohibition of access to power of non-liberal political parties of the leaders of the Cold War is also in line with the fundamental difference, which distinguishes it from dictatorships of the Iberian Peninsula. The latter are related to the same phenomena of

Algal and bacterial activities in acidic (pH 3) strip mine lakes

International Nuclear Information System (INIS)

Gyure, R.A.; Konopka, A.; Brooks, A.; Doemel, W.

1987-01-01

Reservoir 29 and Lake B are extremely acid lakes (epilimnion pHs of 2.7 and 3.2, respectively), because they receive acidic discharges from coal refuse piles. They differ in that the pH of profundal sediments in Reservoir 29 increased from 2.7 to 3.8 during the period of thermal stratification, whereas permanently anoxic sediments in Lake B had a pH of 6.2. The pH rise in Reservoir 29 sediments was correlated with a temporal increase in H 2 S concentration in the anaerobic hypolimnion from 0 to >1 mM. The chlorophyll a levels in the epilimnion of Reservoir 29 were low, and the rate of primary production was typical of an oligotrophic system. However, there was a dense 10-cm layer of algal biomass at the bottom of the metalimnion. Production by this layer was low owing to light limitation and possibly H 2 S toxicity. The specific photosynthetic rates of epilimnetic algae were low, which suggests that nutrient availability is more important than pH in limiting production. The highest photosynthetic rates were obtained in water samples incubated at pH 2.7 to 4. Heterotrophic bacterial activity (measured by [ 14 C]glucose metabolism) was greatest at the sediment/water interface. Bacterial production (assayed by thymidine incorporation) was as high in Reservoir 29 as in a nonacid mesotrophic Indiana lake

Vegetation of high-altitude fens and restio marshlands of the Hottentots Holland Mountains, Western Cape, South Africa

Directory of Open Access Journals (Sweden)

E. J. J. Sieben

2004-09-01

Full Text Available Seepages occurring at high altitudes in the Hottentots Holland Mountains (HHM (Western Cape Province. South Africa were subject to a phytosociological survey. Relevé sampling method and classification procedures of the floristic-sociological (Braun-Blanquet approach as well as numerical data analyses (numerical classification and ordination were used to reveal syn- taxonomic patterns and characterize the position of the syntaxa along major environmental gradients. Nine plant communities were recognized, three of which were classified as associations, following formal syntaxonomic and nomenclatural rules of the floristic-sociological approach Most of the studied mire communities were dominated by low-growing clonal restios (Restionaceae. whereas some consisted of other types of graminoids. The most important species determining the structure (and function of the mire communities on sandstones of the HHM include restios Anthochortus crinalis, Chondropetalum deustum.C. mucronatum, Elegia intermedia. E. thyrsifera. Restio subtilis. R. purpurascens. cyperoids Epischoenus villosus. Ficinia argy-ropa, grasses Ehrharta setacea subsp. setacea. Pentameris hirtiglumis as well as shrubs Berzelia squarrosa. Cliffortia tricuspi- data. Erica intenallaris and Grubbia rosmarinifolia. Protea lacticolor and Restio perplexus dominate a rare shale band seep­age community. There are two major groups of communities—the fens (dominated by carpets of Anthochortus crinalis and other low-growing species and the restio marshlands (mosaics of low tussocks of Restio subtilis and tall Chondropetalum mucrona­tum. The degree of soil (and water minerotrophy was found to be the most important differentiating feature between the mire (fen and restio marshland communities studied. The soils in the centre of mires were found to have high contents of peat and showed very little influence from the underlying sandstone. The soils along the mire margins had a greater admixture of

Caracterización morfológica y relaciones fenéticas entre especies de los órdenes liliales y poales

OpenAIRE

Guevara O, Lorena; Benítez de Rojas, Carmen

2004-01-01

Con el fin de realizar la caracterización morfológica, comparar y discutir acerca de las posibles relaciones fenéticas, se estudiaron 19 especies pertenecientes a 8 familias del orden Liliales (Cronquist, 1988) y 2 especies de la familia Poaceae subfamilia Bambusoideae (Judd et al., 1999). Se analizaron especímenes colectados en diferentes regiones del país, y otros depositados en el herbario "Víctor Manuel Badillo" de la Facultad de Agronomía de la Universidad Central de Venezuela (MY). Con ...

O olhar dos psiquiatras brasileiros sobre os fenômenos de transe e possessão Brazilian psychiatrists’ approaches on trance and possession phenomena

Directory of Open Access Journals (Sweden)

Angélica A. Silva de Almeida

2007-01-01

Full Text Available CONTEXTO: Os fenômenos de transe e possessão despertaram o interesse da comunidade psiquiátrica brasileira, gerando posturas diversificadas. OBJETIVOS: Descrever e analisar como os fenômenos de transe e possessão foram tratados pelos psiquiatras brasileiros: seu impacto na teoria, na pesquisa e na prática clínica entre 1900 e 1950. MÉTODO: Análise de artigos científicos e leigos, teses e livros sobre transes e possessões produzidos pelos psiquiatras brasileiros entre 1900 e 1950. RESULTADOS: Identificam-se duas correntes de pensamento entre os psiquiatras. A primeira, vinculada às Faculdades de Medicina do Rio de Janeiro e São Paulo, sob forte influência de autores franceses, deteve-se mais na periculosidade do espiritismo para a saúde mental. Defendia a adoção de medidas repressivas com o poder público. O segundo grupo de psiquiatras, ligado às Faculdades de Medicina da Bahia e Pernambuco, embora não desconsiderasse o caráter patológico ou "primitivo" dos fenômenos de transe e possessão, apresentou uma visão mais antropológica e culturalista. Considerando tais fenômenos como manifestações étnicas ou culturais, alguns defenderam o controle médico e a educação do povo para o abandono dessas práticas "primitivas". Outros não consideravam os fenômenos mediúnicos como desencadeadores da loucura, mas manifestações não-patológicas de um universo cultural, além de não vinculá-los ao atraso cultural da população. CONCLUSÕES: As religiões mediúnicas foram objeto de estudo por longo período, resultando hipóteses e práticas diferenciadas por parte da comunidade psiquiátrica brasileira, constituindo-se oportunidade privilegiada para o estudo do impacto dos fatores socioculturais na atividade psiquiátrica.BACKGROUND: Trance and possession experiences have raised interest among Brazilian psychiatrists resulting in a variety of approaches. OBJECTIVES: To describe and analyze how Brazilian psychiatrists

Compostos fenólicos e atividade antimicrobiana de Myracrodruon ...

African Journals Online (AJOL)

Usuario

2012-04-20

Apr 20, 2012 ... dichlorophenoxyacetic acid (2,4-D). After inoculation, the ... spectrophotometer UV-VIS (Analyser 850M) at 760 nm, using gallic acid as standard. ... and against the following isolates of fungi: Candida albicans. ATCC14053 ...

Una mirada al fenómeno de la violencia escolar en Costa Rica

Directory of Open Access Journals (Sweden)

Leonel Arias-Sandoval

2009-06-01

En el actual contexto educativo, padres de familia, estudiantes, docentes, medios de comunicación y demás sectores de la sociedad costarricense, manifiestan su preocupación ante el problema de la violencia escolar, fenómeno social que ha venido en aumento en los últimos años. Sus manifestaciones se perciben por medio de conductas de maltrato, intimidación, agresión verbal o física entre jóvenes, y que se construye por medio de prácticas culturales. De ahí que, para comprender este problema, se debe reflexionar acerca de las posibles causas, teniendo en cuenta el contexto en el cual se desarrolla la convivencia social en cada centro educativo. Algunas de las manifestaciones de violencia tienen su origen en la familia, en la comunidad, en la imitación de patrones de conducta y en la influencia de los medios de información de masa. Además, estos comportamientos son potenciados por el modelo curricular vigente, lo que genera resistencia a las normas institucionales.

Three-dimensional information extraction from GaoFen-1 satellite images for landslide monitoring

Science.gov (United States)

Wang, Shixin; Yang, Baolin; Zhou, Yi; Wang, Futao; Zhang, Rui; Zhao, Qing

2018-05-01

To more efficiently use GaoFen-1 (GF-1) satellite images for landslide emergency monitoring, a Digital Surface Model (DSM) can be generated from GF-1 across-track stereo image pairs to build a terrain dataset. This study proposes a landslide 3D information extraction method based on the terrain changes of slope objects. The slope objects are mergences of segmented image objects which have similar aspects; and the terrain changes are calculated from the post-disaster Digital Elevation Model (DEM) from GF-1 and the pre-disaster DEM from GDEM V2. A high mountain landslide that occurred in Wenchuan County, Sichuan Province is used to conduct a 3D information extraction test. The extracted total area of the landslide is 22.58 ha; the displaced earth volume is 652,100 m3; and the average sliding direction is 263.83°. The accuracies of them are 0.89, 0.87 and 0.95, respectively. Thus, the proposed method expands the application of GF-1 satellite images to the field of landslide emergency monitoring.

Modeling thermodynamics of Fe-N phases; characterisation of e-Fe2N1-z

DEFF Research Database (Denmark)

Pekelharing, M.I.; Böttger, A.; Somers, Marcel A.J.

1999-01-01

In order to arrive at modeling the thermodynamics of Fe-N phases, including long-range (LRO) and short-range ordering (SRO) of the N atoms, it is important to understand the role of N interstitially dissolved in an Fe-host lattice. The crystal structure of -Fe2N1-z consists of an h.c.p. iron...... sublattice and a hexagonal nitrogen sublattice formed by octahedral interstices of the Fe sublattice [1]. Two ground-state structures have been proposed for the ordered arrangement of the N atoms on their own sublattice [1], which were shown to be thermodynamically favourable [2]: configuration A for Fe2N1...... investigated with X-ray diffraction (XRD) and Mössbauer spectroscopy. A thermodynamic model accounting for the two configurations of LRO of the N atoms [2,3] was fitted to the N-absorption isotherm at 723 K and resulted in the occupancies of the sites of the nitrogen sublattice. A miscibility gap between...

[Methanotrophic bacteria of acid sphagnum bogs].

Science.gov (United States)

Dedysh, S N

2002-01-01

Acid sphagnum bogs cover a considerable part of the territory of Russia and are an important natural source of biogenic methane, which is formed in their anaerobic layers. A considerable portion of this methane is consumed in the aerobic part of the bog profile by acidophilic methanotrophic bacteria, which comprise the methane filter of sphagnum bogs and decrease CH4 emission to the atmosphere. For a long time, these bacteria escaped isolation, which became possible only after the elucidation of the optimal conditions of their functioning in situ: pH 4.5 to 5.5; temperature, from 15 to 20 degrees C; and low salt concentration in the solution. Reproduction of these conditions and rejection of earlier used media with a high content of biogenic elements allowed methanotrophic bacteria of two new genera and species--Methylocella palustris and Methylocapsa acidophila--to be isolated from the peat of sphagnum bogs of the northern part of European Russia and West Siberia. These bacteria are well adapted to the conditions in cold, acid, oligotrophic sphagnum bogs. They grow in a pH range of 4.2-7.5 with an optimum at 5.0-5.5, prefer moderate temperatures (15-25 degrees C) and media with a low content of mineral salts (200-500 mg/l), and are capable of active nitrogen fixation. Design of fluorescently labeled 16S rRNA-targeted oligonucleotide probes for the detection of Methylocella palustris and Methylocapsa acidophila and their application to the analysis of sphagnum peat samples showed that these bacteria represent dominant populations of methanotrophs with a density of 10(5)-10(6) cells/g peat. In addition to Methylocella and Methylocapsa populations, one more abundant population of methanotrophs was revealed (10(6) cells/g peat), which were phylogenetically close to the genus Methylocystis.

Atividade antimicrobiana de derivados fenólicos do líquen Ramalina sorediosa (B. de Lesd. Laundron Antimicrobian activity of phenols actives from the liquen Ramalina sorediosa (B. de Lesd. Laundron

Directory of Open Access Journals (Sweden)

Emerson P. da Silva Falcão

2004-12-01

Full Text Available A atividade antimicrobiana de extratos brutos de Ramalina sorediosa foi detectada pelo método de difusão em disco de papel. Dois metabólitos liquênicos de natureza fenólica foram identificados por meio de técnicas biocromatográficas. Uma dessas substâncias foi identificada por meio de cromatografia em camada delgada como sendo o ácido úsnico. A segunda substância, que se encontra presente em maior concentração em relação aos demais constituintes nos extratos, trata-se do ácido homossequicáico. As análises em cromatografia em camada delgada (CCD e cromatografia líquida de alta eficiência (CLAE revelaram ainda a presença do ácido salazínico. Os dados obtidos tornam possível atribuir a atividade antibiótica observada nesta espécie a uma provável associação sinérgica destas substâncias.The antimicrobian activity of crude extracts from Ramalina sorediosa was detected by the diffusion disc-paper method. Two phenolic compounds from the lichen considered active were detected by using biochromathograhyc technique. Two of those compounds were identified through thin layer chromatographic technique (TLC as been usnic acid and the second one, wich is present in higher concentration when compared with the other substances, was the homosekikaik acid. The TLC and high-pressure liquid chromatography (HPLC assays still detected the salazanic acid presence. The obtained data make it possible to attribute the antibiotic activity of this species to a synergic association of those two substances.

Evaluation of 54Fe(n,2n)53m+gFe reaction cross sections for high energy dosimetry applications

International Nuclear Information System (INIS)

Zolotarev, K.I.; Pashchenko, A.B.

2001-01-01

The new evaluation of excitation function for the high energy threshold 54 Fe(n,2n) 53m+g Fe dosimetry reaction in the energy range from the threshold to 20 MeV is briefly described. The cross section uncertainties and the covariance matrix were estimated simultaneously from the analysis. The adopted curve is compared to the available processed experimental data and the existing FEI-93, ENDF/B-VI and JENDL-3.2 evaluations. The ENDF-6 formatted data file is available from the Web site of the Russian Nuclear Data Center (RNDC) online (http://www.rndc.ippe.obninsk.ru). (author)

El fenómeno de la infoxicación visto desde la neurociencia : ¿Qué hay de nuevo?

OpenAIRE

Orgaz Camacho, Alexandra

2014-01-01

El fenómeno de la infoxicación desde un punto de vista psicológico podemos definirlo como un estado percibido negativo, caracterizado por síntomas de estrés psicológico, alteración del proceso de toma de decisiones y en general pérdida de la capacidad de procesar y utilizar información de manera eficiente. A pesar de que el concepto como tal es de reciente uso, esta descripción de sintomatología ha sido ampliamente estudiada tanto desde la psicología como desde la neurociencia,...

Impacts of road construction and removal on the hydrologic and geochemical function of a fen peatland

Science.gov (United States)

Wells, C. M.; Petrone, R. M.; Sutherland, G.; Price, J. S.

2015-12-01

Linear disturbances such as roads cover vast swaths of northeastern Alberta, the majority of which are wetlands with shallow and local hydrologic connections. Thus, the effects of road construction on wetland hydrological pathways can have significant implications on water movement within the region, and by extension the productivity of vegetation communities and carbon sequestration. However, little is known about the effect that roads have on wetland hydrology. In 2013, a gravel road built within a fen peatland was reclaimed to evaluate hydrologic impacts post removal. Prior to removal, ground and surface water flow was obstructed leading to surface ponding, and vegetation mortality was observed on the up-gradient (wet) side of the road. Rebounding of the peat column was observed throughout the fen immediately following road removal in 2013 (maximum of 12 cm, mean of 2 cm), with modest but slightly smaller expansion in 2014. For both years, peat rebound was greatest in areas where the road was removed. Peat physical properties contrasted sharply between the reclaimed road (RR) peat and the adjacent, unimpacted peatland (UP). Surface bulk densities (pb, 0-10 cm) ranged from 0.1-0.25 g cm-3 along the RR compared to 0.02-0.07 g cm-3 for the UP and on average, pb for all depths were lower at the RR compared to the UP. Similar spatial patterns were observed for peat porosity. Correspondingly low horizontal saturated hydraulic conductivities (Kh) were observed along the RR compared to the UP, averaging 5.7x10-4 m s-1 and 1.7x10-3 m s-1, respectively. The local flow system across the RR and thus subsurface flow was impeded by almost half (0.4 m d-1) compared to flow observed within the UP (0.8 m d-1), leading to ponding on the upgradient side. A marked change in hydrophysical properties and ground and surface water flow patterns post road removal has implications for plant reestablishment and restoration and will form the basis of further study.

A critical role for very long-chain fatty acid elongases in oleic acid-mediated Saccharomyces cerevisiae cytotoxicity.

Science.gov (United States)

Wang, Qiao; Du, Xiuxiu; Ma, Ke; Shi, Ping; Liu, Wenbin; Sun, Jing; Peng, Min; Huang, Zhiwei

2018-03-01

Elongases FEN1/ELO2 and SUR4/ELO3 are important enzymes involved in the elongation of long-chain fatty acids (LCFAs) to very long-chain fatty acids (VLCFAs) in Saccharomyces cerevisiae. The molecular mechanism of the involvement of these elongases in lipotoxicity is unclear. In the present study, we investigated the role of VLCFA elongases in oleic acid-mediated yeast cytotoxicity. The spot test showed that yeast strains with the deletion of ELO2 or ELO3 were strikingly sensitive to oleic acid, while there was no change on the growth of strain with deleted ELO1 which was involved in the elongation of C 14 fatty acid (FA) to C 16 FA. By using GC-MS, the unsaturation index was increased in elo2△ and elo3△ mutants after treatment with oleic acid (OLA). However, the proportion of VLCFAs was increased in response to OLA in the wild-type strain. The growth inhibition of elo2△ and elo3△ could be partially rescued by two commonly used antioxidant agents N-acetyl cysteine (NAC) and Ascorbic acid (VC). The further study showed that exposure to excess OLA led to an increase in the levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), and a decline in the quantity of reduced glutathione (GSH) in both the wild type and mutant strains. However, the antioxidant enzyme activities of superoxide dismutase (SOD) and catalase (CAT) were increased in the wild type and elo1△ strains, while they were significantly decreased in the mutants of elo2△ and elo3△ after treated with excess OLA. Thus, oxidative damage mainly contributed to the cell death induced by OLA in ole2△ and ole3△. Taken together, although disruption of ELO2 or ELO3 did not affect the cellular lipid unsaturation, they altered the distribution and propotion of cellular VLCFAs, leading to the cell membrane impairment, which augmented the ability of OLA to permeabilize the plasma membrane. The data suggest that the very long-chain fatty acids elongases ELO2 and ELO3

Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown

Energy Technology Data Exchange (ETDEWEB)

Peltoniemi, K

2010-07-01

Boreal peatlands represent a considerable portion of the global carbon (C) pool. Water-level drawdown (WLD) causes peatland drying and induces a vegetation change, which affects the decomposition of soil organic matter and the release of greenhouse gases (CO{sub 2} and CH{sub 4}). The objective of this thesis was to study the microbial communities related to the C cycle and their response to WLD in two boreal peatlands. Both sampling depth and site type had a strong impact on all microbial communities. In general, bacteria dominated the deeper layers of the nutrient-rich fen and the wettest surfaces of the nutrient-poor bog sites, whereas fungi seemed more abundant in the drier surfaces of the bog. WLD clearly affected the microbial communities but the effect was dependent on site type. The fungal and methane-oxidizing bacteria (MOB) community composition changed at all sites but the actinobacterial community response was apparent only in the fen after WLD. Microbial communities became more similar among sites after long-term WLD. Litter quality had a large impact on community composition, whereas the effects of site type and WLD were relatively minor. The decomposition rate of fresh organic matter was influenced slightly by actinobacteria, but not at all by fungi. Field respiration measurements in the northern fen indicated that WLD accelerates the decomposition of soil organic matter. In addition, a correlation between activity and certain fungal sequences indicated that community composition affects the decomposition of older organic matter in deeper peat layers. WLD had a negative impact on CH{sub 4} oxidation, especially in the oligotrophic fen. Fungal sequences were matched to taxa capable of utilizing a broad range of substrates. Most of the actinobacterial sequences could not be matched to characterized taxa in reference databases. This thesis represents the first investigation of microbial communities and their response to WLD among a variety of boreal

Deciphering the role of Paenibacillus strain Q8 in the organic matter recycling in the acid mine drainage of Carnoulès

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Delavat François

2012-02-01

Full Text Available Abstract Background The recycling of the organic matter is a crucial function in any environment, especially in oligotrophic environments such as Acid Mine Drainages (AMDs. Polymer-degrading bacteria might play an important role in such ecosystem, at least by releasing by-products useful for the rest of the community. In this study, physiological, molecular and biochemical experiments were performed to decipher the role of a Paenibacillus strain isolated from the sediment of Carnoulès AMD. Results Even though Paenibacillus sp. strain Q8 was isolated from an oligotrophic AMD showing an acidic pH, it developed under both acidic and alkaline conditions and showed a heterotrophic metabolism based on the utilization of a broad range of organic compounds. It resisted to numerous metallic stresses, particularly high arsenite (As(III concentrations (> 1,800 mg/L. Q8 was also able to efficiently degrade polymers such as cellulose, xylan and starch. Function-based screening of a Q8 DNA-library allowed the detection of 15 clones with starch-degrading activity and 3 clones with xylan-degrading activity. One clone positive for starch degradation carried a single gene encoding a "protein of unknown function". Amylolytic and xylanolytic activities were measured both in growing cells and with acellular extracts of Q8. The results showed the ability of Q8 to degrade both polymers under a broad pH range and high As(III and As(V concentrations. Activity measurements allowed to point out the constitutive expression of the amylase genes and the mainly inducible expression of the xylanase genes. PACE demonstrated the endo-acting activity of the amylases and the exo-acting activity of the xylanases. Conclusions AMDs have been studied for years especially with regard to interactions between bacteria and the inorganic compartment hosting them. To date, no study reported the role of microorganisms in the recycling of the organic matter. The present work suggests that

O fenômeno do esvaziamento populacional em municípios do Rio Grande do Sul–Brasil sob a lente da Abordagem das Capacidades

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Airton Adelar Mueller

2016-12-01

Full Text Available Durante a década 2000-2010 mais da metade dos municípios do Rio Grande do Sul vivenciou uma redução absoluta de sua população, o que se deu de maneira particularmente acentuada no noroeste do estado. Tal fenômeno segue pouco estudado até o momento, sobretudo no que tange às causas subjacentes e implicações no desenvolvimento de indivíduos e coletividades regionais nele envolvidas. Neste artigo se busca sanar parte desta lacuna, abordando a problemática sob as contribuições teóricas de Amartya Sen, particularmente a partir de seu conceito de Agência e das correlatas noções de Poder e Controle. Baseado em evidências colhidas na literatura, em dados socioeconômicos e demográficos e no uso de métodos estatísticos evidencia-se que das diferentes dimensões do desenvolvimento humano (Saúde, Renda, Educação, a mais diretamente associada ao fenômeno migratório é a dimensão que reflete as atividades econômicas (Renda. Argumenta-se que em função de uma estrutura produtiva regional agroexportadora de bens primários, grande parte da população local vê sua condição de Agente severamente tolhida em função de sua não inclusão nestas atividades produtivas e em função de que estas atividades são comandadas por agentes multinacionais externos à região. Disso resulta, entre outras consequências, o fenômeno de esvaziamento populacional, dado que a emigração, enquanto ato que implica Agência individual ou familiar, está muito mais sob o Poder e o Controle dos habitantes locais do que os mecanismos, processos e atores que subjazem às principais atividades produtivas regionais.

Antioxidant activity and phenolic content of agricultural by-products from wine production/ Atividade antioxidante e conteúdo fenólico do resíduo agroindustrial da produção de vinho

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Eugênia Marta Kuskoski

2008-08-01

Full Text Available The present work aimed to investigate the antioxidant properties of byproducts derived from wine production. The varieties of PINOT GRIS and COUDERC 13 grapes, collected in Videira-SC, were analyzed as natural sources of polyphenols and other prophylactic agents (antioxidants for application in food and phytochemical industries. The biomass used for extracts was ground and dried in different temperatures (45oC, 60oC e 80oC, using acetone 80% as solvent. The phenolic compounds were quantitatively evaluated by the Folin-Ciocalteu method and the results expressed in mg/100g of Gallic acid. For the flavonoids analysis, it was applied DMACA (p- Dimethylaminocinnamaldehye method and the results were expressed in equivalent mg of catechin/100g sample. The antioxidant activity was evaluated by spectrophotometric method through the discoloration of ABTS•+ radical (2,2'-azino-bis[3- ethylbenzthiazoline-6-sulfonic acid] with potassium persulphate and by DPPH method, which is based on the reduction of DPPH• radical absorbance by antioxidant substances; the results were expressed in TEAC (antioxidant activity equivalent to Trolox and VCEAC (antioxidant activity equivalent to vitamin C. It was observed a better antioxidant activity on extracts obtained from PINOT GRIS grapes, in which the 45 oC dried extracts presented a higher number of phenolic compounds and flavonoids, as well as a better antioxidant activity in both varieties. These information become useful for phenolic compounds identifying and for a possible using of these extracts as a secure additive in food industry.Este trabalho propõe uma investigação do potencial antioxidante do resíduo no processamento de uvas das variedades COUDERC 13 e PINOT GRIS, ambas coletadas em Videira-SC, como fonte natural de polifenóis e outros agentes profiláticos (antioxidantes para aplicação nas indústrias alimentícia e de fitoterápicos. A biomassa utilizada para obtenção dos extratos foi triturada

Uma nosologia para os fenômenos sobrenaturais e a construção do cérebro 'possuído' no século XIX

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Valeria Portugal Goncalves

2013-06-01

Full Text Available Fenômenos sobrenaturais como os chamados transe e possessão espiritual recebem, no final do século XX, codificação científica, integrando os diagnósticos da psiquiatria hegemônica. No final do século XIX, observamos a apropriação científica de fenômenos considerados originários da superstição ou imaginação popular. Neste trabalho, demonstramos como o transe e a possessão espiritual foram estudados por Franz Anton Mesmer e seus discípulos ao desenvolver o conceito de magnetismo; por James Braid no processo de criação da teoria da hipnose; e por Jean Martin Charcot, marcando a entrada da histeria para as classificações nosológicas. Apesar das diferenças entre essas escolas, identificamos a utilização do cérebro e de metáforas cerebralistas como alicerce das teorias sobre a mente.

Investigation of the mobilizability of persistent pollutants in the system groundwater/soil/plant of a former fen

International Nuclear Information System (INIS)

Hein, D.; Goertz, W.; Leisner-Saaber, J.; Rathje, M.

1993-01-01

For a former fen situated at the eastern border of the Lower terraces of the river Rhine in the close neighbourhood of densely populated urban districts a biotope-managementplan suggests the rewetting and restauration of typical landscape forms. High concentrations of heavy metals and low pH-values of the soil imply a potential danger especially for the groundwater. In order to solve this conflict between the aims of protecting rare biotopes and of saving groundwater-resources investigations were carried out considering all environmental compartments concerned: groundwater, surfacewater, soil and plants. The results demonstate that a step-by-step rewetting of the area is possible without a previous exchange of soil. In addition, careful groundwater control has to be carried out. (orig.) [de

Impacts of light shading and nutrient enrichment geo-engineering approaches on the productivity of a stratified, oligotrophic ocean ecosystem.

Science.gov (United States)

Hardman-Mountford, Nick J; Polimene, Luca; Hirata, Takafumi; Brewin, Robert J W; Aiken, Jim

2013-12-06

Geo-engineering proposals to mitigate global warming have focused either on methods of carbon dioxide removal, particularly nutrient fertilization of plant growth, or on cooling the Earth's surface by reducing incoming solar radiation (shading). Marine phytoplankton contribute half the Earth's biological carbon fixation and carbon export in the ocean is modulated by the actions of microbes and grazing communities in recycling nutrients. Both nutrients and light are essential for photosynthesis, so understanding the relative influence of both these geo-engineering approaches on ocean ecosystem production and processes is critical to the evaluation of their effectiveness. In this paper, we investigate the relationship between light and nutrient availability on productivity in a stratified, oligotrophic subtropical ocean ecosystem using a one-dimensional water column model coupled to a multi-plankton ecosystem model, with the goal of elucidating potential impacts of these geo-engineering approaches on ecosystem production. We find that solar shading approaches can redistribute productivity in the water column but do not change total production. Macronutrient enrichment is able to enhance the export of carbon, although heterotrophic recycling reduces the efficiency of carbon export substantially over time. Our results highlight the requirement for a fuller consideration of marine ecosystem interactions and feedbacks, beyond simply the stimulation of surface blooms, in the evaluation of putative geo-engineering approaches.

Plankton origin of particulate dimethylsulfoniopropionate in a Mediterranean oligotrophic coastal and shallow ecosystem

Science.gov (United States)

Jean, Natacha; Bogé, Gérard; Jamet, Jean-Louis; Jamet, Dominique; Richard, Simone

2009-03-01

We report here dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) levels as a function of plankton communities and abiotic factors over a 12-month cycle in the Mediterranean oligotrophic coastal and shallow ecosystem of Niel Bay (N.W. Mediterranean Sea, France). Total particulate DMSP (DMSP p) and DMS concentrations were highly seasonal, peaking during a spring (April) bloom at 8.9 nM and 73.9 nM, respectively. Significant positive correlations were found between total DMSP p concentration and the abundance or biomass of the dinoflagellate Prorocentrum compressum (Spearman's rank correlation test: r = 0.704; p = 0.011). Similarly, DMS concentrations peaked during the development of blooms of P. compressum and Gymnodinium sp. There seemed to be a positive relationship between the chlorophyll a to pheopigment ratio and DMS concentrations, suggesting that DMS was released during phytoplankton growth. High DMS levels recorded in the shallow Niel Bay may also result from the activity of benthic macroalgae, and/or macrophytes such as Posidonia spp., or the resuspension of sulfur species accumulating in sediments. The fractionation of particulate DMSP into three size classes (>90 μm, 5-90 μm and 0.2-5 μm) revealed that 5-90 μm DMSP-containing particles made the greatest contribution to the total DMSP p pool (annual mean contribution = 62%), with a maximal contribution in April (96%). This size class consisted mainly of dinoflagellates (annual mean contribution = 68%), with P. compressum and Gymnodinium sp. the predominant species, together accounting for up to 44% of the phytoplankton present. The positive correlation between DMSP concentration in the 5-90 μm size class and the abundance of P. compressum (Spearman's rank correlation test: r = 0.648; p = 0.023) suggests that this phytoplankton species would be the major DMSP producer in Niel Bay. The DMSP collected in the >90 μm fraction was principally associated with zooplankton organisms, dominated by

Vitamina C, carotenoides, fenólicos totais e atividade antioxidante de goiaba, manga e mamão procedentes da Ceasa do Estado de Minas Gerais - doi: 10.4025/actascihealthsci.v33i1.8052 Vitamin C, carotenoids, phenolic compounds and antioxidant activity of guava, mango and papaya from Ceasa of Minas Gerais State - doi: 10.4025/actascihealthsci.v33i1.8052

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Helena Maria Pinheiro-Sant'Ana

2011-05-01

Full Text Available Este estudo teve como objetivo analisar o conteúdo de compostos antioxidantes (ácido ascórbico - AA, ácido desidroascórbico - ADA, vitamina C total, licopeno, β-caroteno, β-criptoxantina e estimativa de compostos fenólicos e avaliar a atividade antioxidante, em goiaba, manga e mamão. A análise de carotenoides e vitamina C foi realizada por Cromatografia Líquida de Alta Eficiência (CLAE. O teor de fenólicos totais foi determinado utilizando o reagente de Folin-Ciocalteu e leitura espectrofotométrica. A atividade antioxidante foi avaliada pelo Teste do 2,2-diphenil-2-picril-hidrazil (DPPH• e do Poder Redutor. A Anova (α = 0,05 foi utilizada para a análise dos dados. Os teores dos constituintes antioxidantes diferiram entre as três frutas, mas a goiaba foi a fruta que apresentou teores mais elevados de compostos fenólicos, vitamina C total, ADA e licopeno, além dos maiores valores para atividade antioxidante. Foi constatada forte correlação entre os testes que avaliaram a atividade antioxidante e o teor de fenólicos totais, demonstrando serem estes os principais compostos antioxidantes a contribuírem para a atividade antioxidante das frutas analisadas, em ambos os testes. É importante incentivar a utilização das frutas avaliadas neste estudo, tanto em nível doméstico quanto em estabelecimentos de alimentação coletiva para aumentar o consumo de antioxidantes naturais pela população.This study aimed to analyze the content of antioxidant compounds (ascorbic acid - AA, dehydroascorbic acid - DHA, total vitamin C, lycopene, β-carotene, β-cryptoxanthin and phenolic compounds and to evaluate the antioxidant activity in guava, mango and papaya. The analysis of carotenoids and vitamin C was performed by high performance liquid chromatography (HPLC. The content of phenolic compounds was determined using the Folin-Ciocalteu reagent and spectrophotometric reading. Antioxidant activity was evaluated by testing the 2

El fenómeno del Greenwashing y su impacto sobre los consumidores

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Moritz Hallama

2011-07-01

Full Text Available Hoy en día y mediante una publicidad sofisticada, las empresas tratan de proyectar una imagen respetuosa con el medio ambiente en la percepción de los consumidores. Esta imagen no refleja necesariamente la realidad. Se habla de “Greenwashing” cuando una empresa utiliza la ampliación selectiva de información medioambiental positiva con la finalidad de causar una imagen distorsionada donde los aspectos positivos predominan mas del debido. Este artículo pretende de abordar este fenómeno y avaluar su existencia, importancia y el efecto causado sobre los consumidores mediante el diseño de una metodología piloto para la investigación, aplicando ésta a una muestra de estudiantes. Los resultados indican que la imagen transmitida por la publicidad de cinco grandes empresas seleccionadas contrasta con ejemplos de mala gestión y que esta manipulación influye en la percepción que tiene la muestra encuestada. Los estudiantes de Ciencias Ambientales encuestados presentan ser ligeramente más resistentes contra el Greenwashing debido a su formación, pero también incorporan mayoritariamente el discurso oficial procedente de las relaciones públicas empresariales.

Gobierno corporativo en la micro, pequeña y mediana empresa en Colombia, un acercamiento al fenómeno del emprendimiento

OpenAIRE

Olarte Ortega, Juan David; Montoya Ríos, Pablo

2017-01-01

El Gobierno Corporativo tiene una implementación, ya usual, en las grandes compañías, sin embargo, el análisis muestra que su ámbito de aplicación se puede extender a actores que apenas lograron consolidar empresa o apenas ponen en marcha sus ideas de negocio, de esta idea surge la necesidad de la posible consolidación del Gobierno Corporativo en la micro, pequeña y mediana empresa en Colombia, teniendo presente el emprendimiento como fenómeno económico determinante para explicar las ventajas...

Geogebra, una herramienta para la enseñanza de las matemáticas y simulación de fenómenos

OpenAIRE

Camacho, Noé; Godínez, Margarito; Velázquez, Santiago

2014-01-01

Hoy en día es de suma importancia relacionar los conocimientos adquiridos en el aula con la sociedad, el entorno, los fenómenos que observamos y los que acontecen en nuestra sociedad, esta labor es principalmente de los docentes, no obstante, en la mayoría de las veces no se dispone de ofertas de capacitado para construir las referidas herramientas y de esta manera llevar acabo esta relación, el objetivo del taller propuesto fue precisamente capacitar a estudiantes y profesores en la modelaci...

Liming the acid lake Hovvatn, Norway: a whole-ecosystem study

Energy Technology Data Exchange (ETDEWEB)

Raddum, G G; Brettum, P; Matzow, D; Nilssen, J P; Skov, A; Sveaelv, T; Wright, R F

1986-12-01

Hovvatn, a 1 sq. km. chronically-acidified lake in southernmost Norway, was treated with 200 tonne of powdered limestone in March 1981. An additional 40 tonne were added to a 0.046 sq km pond (Pollen) draining into Hovvatn. The lakes were stocked with brown trout in June 1981 and in each subsequent year. At ice-out pH rose from 4.4 to 6.3 (Hovvatn) and 7.5 (Pollen), Ca and alkalinity increased, and total Al decreased by 120 ..mu..g/l. None of the other major ions exhibited significant changes in concentration. Total organic C and P increased after liming. The phytoplankton community was dominated by chrysophytes and did not change significantly following liming. The zooplankton community was typical of acid lakes prior to liming. There was a clear succession in species dominance following treatment, although no new species immigrated to the lakes. Zoobenthos changed from a community characterized by low abundance and reduced number of species to increased abundance of oligochaetes, mayflies and chironomids. Hovvatn and Pollen were barren of fish prior to stocking. The stocked fish showed remarkably high growth rate during the first years. Liming apparently improved conditions for zoobenthos, enhancing the processing of fine detritus which in turn resulted in elevated levels of TOC and P in the lakewaters during the first year after liming. The oligotrophication process typical of acid lakes was temporarily reversed by liming. The interactions between groups of organisms in Hovvatn and Pollen indicates that many years are required before a new steady-state can be attained following liming. 61 references.

Idioma y globalización: ¿Un nuevo término para un viejo fenómeno?

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Alba T Estrada Molné

Full Text Available El proceso de globalización implica una comunicación necesaria para poderse llevar a cabo. Pudiera decirse que dicha comunicación se ha hecho posible en nuestros días a través del idioma inglés, pues es el idioma de los negocios, de los avances científico- técnicos y su literatura así como de muchos de los medios masivos de comunicación. Cabe preguntarse si este fenómeno de globalización es algo surgido en este momento histórico- concreto o es una tendencia que tiene antecedentes en el pasado. Es entonces el propósito de este trabajo analizar como a través del devenir histórico de la humanidad, ha existido una expansión de determinados idiomas relacionada con factores hegemónicos tanto económicos como políticos. Se lleva a cabo una reseña histórica que comprende desde el mundo griego hasta el siglo XX. Así mismo se ofrece un panorama del desarrollo de las teorías lingüísticas, filosóficas y pedagógicas en las distintas etapas de la historia. Se pone de manifiesto que desde época tan antigua como la civilización helénica hasta la actualidad se han desarrollado procesos de universalización del idioma de las potencias dominantes en algunas etapas de forma total y en otras parcial según el mundo conocido en esos períodos. Se concluye que la globalización del idioma no es un fenómeno actual sino histórico, que en las teorías lingüísticas y pedagógicas han incidido las dos posiciones filosóficas (materialismo e idealismo presentes en todo el período histórico estudiado y se destaca la posición posmodernista del Enfoque Comunicativo en la enseñanza del inglés y su tendencia primer mundista

Nitrogenous compounds, phenolic compounds and morphological aspects of leaves: comparison of deciduous and semideciduous arboreal legumes Compostos nitrogenados, fenólicos e aspecto morfológico em folhas: comparação entre leguminosas arbóreas semidecíduas e decíduas

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Ana Lúcia da Silva Lima

2006-02-01

Full Text Available In general, perennial species contain higher concentrations of certain secondary compounds, such as phenolics, lower levels of nitrogenous compounds, and greater specific leaf mass (SLM than deciduous species. The aim of this study was to verify whether the comparative data reported in the literature regarding deciduous and evergreen species, also applies to four selected species of a semideciduous tropical forest (a remnant of the Atlantic Forest. The four species chosen for this study, each with apparently different leaf life spans, were two semideciduous (Hymenaea courbaril L. var. stilbocarpa (Hayne Lee et Lang., and Lonchocarpus guilleminianus (Tul. Malme, and two deciduous (Enterolobium contortisiliquum (Vell. Morong., and Peltophorum dubium (Spreng. Taub.. Plants were grown in a greenhouse in plastic pots containing soil taken from their natural habitat. Mature leaves were harvested for determination of the SLM and contents of phenolic compounds, tannins, nitrate, protein, free amino acids, chlorophyll, and nitrogen. Data registered are in agreement with those of the literature. Leaves with the longest life span had the highest content of phenolics and the lowest levels of tannins, nitrate, protein, amino acids, chlorophyll and nitrogen, as well as presenting the greatest SLM.Em geral as espécies perenifólias possuem maior concentração de alguns compostos secundários, como por exemplo fenóis, menor concentração de compostos nitrogenados e maior massa foliar específica (MFE, quando comparadas a espécies decíduas. O objetivo deste trabalho foi verificar se as observações encontradas na literatura, comparando espécies perenifólias e decíduas aplicam-se também a quatro espécies de uma mata semidecídua, remanescente da Mata Atlântica. Das quatro espécies usadas neste estudo, que aparentemente apresentavam longevidades foliares diferentes, duas eram semidecíduas (Hymenaea courbaril L. var. stilbocarpa (Hayne Lee et Lang. e

Commented list of rare and protected vascular plants of inland water bodies of Estonia

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Helle Mäemets

2016-10-01

Full Text Available This presented overview of rare and protected hydrophytes, emergent plants and hygrophytes of inland water bodies of Estonia includes 60 species. In the commented list are indicated their position in the state protection categories I–III (last version in 2014, and under the Red List of Estonia (last version in 2008; marked are Natura 2000 species of the European Union. Most typical habitats for these rare species are: I. soft-water oligotrophic and semidystrophic lakes; II. mesotrophic lakes with Najas (Caulinia flexilis and Potamogeton rutilus; III. alkaline fens and wet meadows; IV. brackish or freshwater coastal lagoons; V. undamaged river stretches; VI. open shallow littoral of the largest lakes of Peipsi (Pskovsko-Chudskoe and of Võrtsjärv. Main threats of these habitats are briefly concerned, as well as the problem of conservation value of hybrids, based on the example of Sparganium species.

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystem

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.A.R.; Heck, I.C.C; Hesen, P.L.G.M.; Leuven, R.S.E.W.; Roelofs, J.G.M.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulphate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulphate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulphate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH 3.8. Under acidified conditions, ammonium sulphate deposition led to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr, the acidification of water appeared to be coupled with changes in alkalinity, sulphate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulphate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 references.

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystems

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.; Heck, I.C.; Hesen, P.L.; Leuven, R.S.; Roelofs, J.G.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulfate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulfate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulfate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH = 3.8. Under acidified conditions, ammonium sulfate deposition lead to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr. The acidification of water appeared to be coupled with changes in alkalinity, sulfate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulfate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 refs.

Optimización de las condiciones de extracción de compuestos fenólicos a partir de cáscara de uva variedad quebranta (Ica, Perú) empleando técnicas convencionales y extracción asistida por ultrasonido

OpenAIRE

Dueñas Zurita, Julia Alicia

2017-01-01

La producción de vino y pisco representa una de las principales actividades agrícolas en todo el mundo, esta producción se acompaña con la generación de grandes cantidades de desechos que son ricos en compuestos bioactivos (especialmente compuestos fenólicos) con capacidad antioxidante. El propósito de este trabajo es seleccionar y optimizar las condiciones de extracción de compuestos fenólicos a partir de cáscara de uva variedad Quebranta provenientes de vinificaciones empleando un método co...

Discriminação social: Um fenómeno que atenta contra a dignidade da pessoa humana

Directory of Open Access Journals (Sweden)

Anselmo Orlando Pinto

2015-06-01

Full Text Available A aparição do outro no nosso horizonte abre a porta a diferentes comportamentos e relações. Esta é a razão pela qual o reconhecimento da humanidade não implica necessariamente a simpatia ou a boa vontade porque pode também comportar conflitos e competitividade. Pretendemos reflectir sobre o conceito da dignidade da pessoa humana e o seu significado ético, tendo em conta a questão da discriminação social, com o intuito de perceber como é que este fenómeno constitui grave atentado à dignidade do homem. A categoria moral da dignidade humana se apoia sobre a afirmação prémoral ou ôntica do valor absoluto do homem.

Fenômenos psíquicos e o problema mente-corpo: notas históricas sobre uma tradição conceitual negligenciada

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Carlos S. Alvarado

2013-01-01

Full Text Available Embora exista uma longa tradição de discussões filosóficas e históricas sobre o problema mente-corpo, a maioria delas não menciona os fenômenos psíquicos como tendo implicações para esse tópico. Este artigo é uma revisão de escritos selecionados publicados na literatura dos séculos XIX e XX sobre o mesmerismo, o espiritualismo e a pesquisa psíquica cujos os autores discutiram sobre aparições, telepatia, clarividência, experiências fora do corpo e outros fenômenos parapsicológicos como evidência para a existência de um princípio separado do corpo e responsável pela consciência. Os autores discutidos são de diferentes períodos de tempo. Entre eles estão John Beloff, J. C. Colquhoun, Camille Flammarion, J. H. Jung-Stilling, Frederic W. H. Myers e J. B. Rhine. Mais do que defender a validade de sua posição, minha proposta é documentar a existência de uma tradição intelectual e conceitual que tem sido negligenciada por filósofos, entre outros, nas discussões sobre o problema mente-corpo e aspectos de sua história.

Microbial communities associated with uranium in-situ recovery mining process are related to acid mine drainage assemblages.

Science.gov (United States)

Coral, Thomas; Descostes, Michaël; De Boissezon, Hélène; Bernier-Latmani, Rizlan; de Alencastro, Luiz Felippe; Rossi, Pierre

2018-07-01

A large fraction (47%) of the world's uranium is mined by a technique called "In Situ Recovery" (ISR). This mining technique involves the injection of a leaching fluid (acidic or alkaline) into a uranium-bearing aquifer and the pumping of the resulting solution through cation exchange columns for the recovery of dissolved uranium. The present study reports the in-depth alterations brought to autochthonous microbial communities during acidic ISR activities. Water samples were collected from a uranium roll-front deposit that is part of an ISR mine in operation (Tortkuduk, Kazakhstan). Water samples were obtained at a depth of ca 500 m below ground level from several zones of the Uyuk aquifer following the natural redox zonation inherited from the roll front deposit, including the native mineralized orebody and both upstream and downstream adjacent locations. Samples were collected equally from both the entrance and the exit of the uranium concentration plant. Next-generation sequencing data showed that the redox gradient shaped the community structures, within the anaerobic, reduced, and oligotrophic habitats of the native aquifer zones. Acid injection induced drastic changes in the structures of these communities, with a large decrease in both cell numbers and diversity. Communities present in the acidified (pH values acid mine drainage, with the dominance of Sulfobacillus sp., Leptospirillum sp. and Acidithiobacillus sp., as well as the archaean Ferroplasma sp. Communities located up- and downstream of the mineralized zone under ISR and affected by acidic fluids were blended with additional facultative anaerobic and acidophilic microorganisms. These mixed biomes may be suitable communities for the natural attenuation of ISR mining-affected subsurface through the reduction of metals and sulfate. Assessing the effect of acidification on the microbial community is critical to evaluating the potential for natural attenuation or active bioremediation strategies

Sobre los saberes culturales y el fenómeno "sentirse bien-sentirse mal" On cultural knowledge and the phenomenon "feel good-fell bad"

OpenAIRE

Virtudes Rodero Sánchez; Carme Vives Relats; Sagrario Acebedo Urdiales; Carme Ferré Grau

2010-01-01

El objetivo del presente estudio es identificar los saberes culturales inmersos en el fenómeno "sentirse-bien, sentirse mal", en diferentes situaciones de cuidado. Se elaboró un estudio cualitativo con un enfoque fenomenológico interpretativo, mediante el análisis de 18 narrativas a partir de entrevistas en profundidad realizadas por alumnas del Máster en Ciencias de la Enfermería en diferentes contextos de cuidados. Las categorías identificadas fueron: (1) Cronicidad y concepto de sentirse b...

Biogeochemistry of carbon and related major and trace elements in peat bog soils of the middle taiga of Western Siberia (Russia).

Science.gov (United States)

Stepanova, V. A.; Mironycheva-Tokareva, N. P.; Pokrovsky, O. S.

2012-04-01

Global climate changes impact the status of wetland ecosystems shifting the balances of the carbon, macro-, and microelements cycles. This study aims to establish the features of accumulation and distribution of major- and trace elements in the organic layer of peat bog soils, belonging to different ecosystems of the oligotrophic bog complex located in the middle taiga of Western Siberia (Khanty-Mansiysk region, Russia). Key areas which are selected for this study include the following bog conjugate elementary ecosystems: higher ryam, lower ryam, ridge-hollow complex, and oligotrophic poor fen as characterized previously [1]. We have sampled various peat types along the entire length of the soil column (every 10 cm down to 3 m). Peat samples were analyzed for a wide range of macro- and microelements using an ICP-MS technique following full acid digestion in a microwave oven. These measurements allowed quantitative estimates of major- and trace elements in the peat deposits within the whole bog complex and individual elementary landscapes. Based on the data obtained, the lateral and radial geochemical structures of the bog landscapes were determined and clarified for the first time for middle taiga of the West Siberian plain. The similar regime of mineral nutrition during the complete bog landscape formation was detected for the peat deposits based on the measurements of some major- and trace elements (Ca, Fe, Mg, etc.). The vertical distribution of some major and some trace elements along the profile of peat column is rather uniform with relatively strong increase in the bottom organic layers. This strongly suggests the similarity of the processes of element accumulation in the peat and relatively weak post depositional redistribution of elements within the peat soil profile. Overall, obtained corroborate the existing view on chemical composition of peats being determined by botanical peat's components (which forms this peat deposit), atmospheric precipitation

Distribution of the insecticide 14 C-fen valerate and its effect on protein and amino acid content in different brain areas of the rat

International Nuclear Information System (INIS)

Aly, M.A.S.

1998-01-01

Intragastric administration of fenvalerate (45 mg/kg) to male rats induced symptoms associated with gamma-cyano pyrethroids (type II syndrome). Fenvalerate crossed blood brain barrier and reached different brain areas. The highest concentration of fenvalerate was found in striatum (18.7+2.5 Mou/g) followed by pons + medulla oblongata (10.4+ 0.91Moug/g) after 24 h of the insecticide administration. A decrease in the protein content in different brain areas was recorded at 24 h. However, it was observed that there was a tendency for the protein level to recover at 48 h although it was still lower than corresponding controlgroup. Excitatory neurotransmitter amino acids, glutamic and aspartic, in the pons + medulla oblongata showed a prominent decrease (-9.9 and 7.0%, respectively). Inhibitory neurotransmitter amino acids, glycine and alanine, showed a slight decrease. On the other hand, the amino acids in the striatum revealed fluctuating changes. Amino acids acting as a precursor of neurotransmitter were also affected in the selected brain areas. The data obtained revealed that fenvalerate caused subtle disruption in the integrity of the CNS and there is a possibility that such disruption might result in physiological and behavioural alteration which may affect the organism ability to interact with environment

Problematizando as práticas psicológicas no modo de compreender o fenômeno assédio moral

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Bruna Meurer

Full Text Available O presente ensaio problematiza os discursos e estereótipos produzidos pelas ciências que incidem sobre homens e mulheres que praticam ou que são vítimas do assédio moral. Discute-se, assim, através de uma apreensão teórica sobre o fenômeno poder nas organizações, a possibilidade de uma reflexão crítica que permita o descolamento das condutas consideradas não morais, mas presentes no mundo do trabalho, do território normativo da patologização e da adaptação dos sujeitos. São realizadas reflexões que permitem compreender como as práticas psi se utilizam de antigos métodos para o controle social dos corpos no aparato social. A partir de uma perspectiva psicossocial, atentamos para o fato de que o assédio moral não se refere apenas a uma conduta individual antissocial, mas está relacionado a condicionantes individuais, grupais, organizacionais e sociais. Por fim, na esteira desses posicionamentos e engendramentos, mostramos que o conceito de assédio moral apresenta ainda outras especificidades que precisam ser visibilizadas face aos estereótipos de gênero produzidos principalmente pelo meio acadêmico, que contribuem para a cristalização de masculinidades e de feminilidades frente a esse fenômeno. Nesse contexto, busca-se reinterpretar os essencialismos, práticas ditas masculinas ou femininas, que têm consequências negativas no mercado laboral e que dificultam a consecução de maior igualdade entre homens e mulheres.

Efecto de los componentes del agua de mar durante el fenómeno de corrosión por picaduras del cobre

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García, E.

1995-10-01

Full Text Available Copper is the main component in Cu-Ni alloys recommended for sea water applications. This work presents the electrochemical behaviour of copper in presence of different sea water components and its influence on the corrosion attack. The combined action of chloride and sulphate ions are the main responsible factor for the localized corrosion attack in the form of pitting. A significant parabolic relation exists between the critical pitting potential (E_p and the weight ratio of chloride to sulphate (Cl^-/SO₄^2- ions. Therefore sulphate ions are an important component for pitting corrosion of copper.

El cobre es el elemento principal de las aleaciones Cu-Ni recomendadas para aplicaciones marinas. En este trabajo se presenta el comportamiento electroquímico del cobre con los diferentes componentes del agua de mar y el efecto de estos sobre la forma de ataque del cobre. Se observó que los iones cloruro, en unión con los iones sulfato, son los principales causantes del fenómeno de corrosión por picaduras, existiendo, además, una relación significativa entre el potencial crítico de picado (E_p y la relación (Cl^-/SO₄^2- de tipo parabólico, lo cual pone de manifiesto la importancia del ion sulfato en el fenómeno de corrosión por picaduras como promotor de este tipo de mecanismo.

Compétition pour l'azote inorganique entre le pelagos et le benthos dans un écosystème côtier oligotrophe. Effets sur la dynamique de l'écosystème.

OpenAIRE

Lepoint, Gilles

2001-01-01

Résumé de la thèse intitulée : Compétition pour l’azote inorganique entre le benthos et le pelagos d’un milieu côtier oligotrophe. Effets sur la dynamique de l’écosystème. Dissertation présentée le 9 mai 2001 par Gilles Lepoint en vue de l’obtention du grade de Docteur en Sciences de l’Université de Liège. Dans la Baie de la Revellata (Calvi, Corse, France), comme dans de nombreux sites côtiers méditerranéens, les biocénoses benthiques sont très développées et productives, malgré le c...

Stable carbon isotope biogeochemistry of lakes along a trophic gradient

NARCIS (Netherlands)

de Kluijver, A.; Schoon, P.L.; Downing, J.A.; Schouten, S.; Middelburg, J.J.

2014-01-01

The stable carbon (C) isotope variability of dissolved inorganic and organic C (DIC and DOC), particulate organic carbon (POC), glucose and polar-lipid derived fatty acids (PLFAs) was studied in a survey of 22 North American oligotrophic to eutrophic lakes. The d13C of different PLFAs were used as

The crustacean zooplankton assemblage of a relatively pristine Utor ...

African Journals Online (AJOL)

The water quality and crustacean zooplankton of Utor River, a relatively pristine freshwater body in Edo State, Nigeria was investigated at four stations. The Utor River is slightly acidic, well oxygenated, oligotrophic and low in solids, conductivity, cations and heavy metals. A total of 380 individuals comprising eleven taxa ...

Root proliferation in decaying roots and old root channels: A nutrient conservation mechanism in oligotrophic mangrove forests?

Science.gov (United States)

McKee, K.L.

2001-01-01

1. In oligotrophic habitats, proliferation of roots in nutrient-rich microsites may contribute to overall nutrient conservation by plants. Peat-based soils on mangrove islands in Belize are characterized by the presence of decaying roots and numerous old root channels (0.1-3.5 cm diameter) that become filled with living and highly branched roots of Rhizophora mangle and Avicennia germinans. The objectives of this study were to quantify the proliferation of roots in these microsites and to determine what causes this response. 2. Channels formed by the refractory remains of mangrove roots accounted for only 1-2% of total soil volume, but the proportion of roots found within channels varied from 9 to 24% of total live mass. Successive generations of roots growing inside increasingly smaller root channels were also found. 3. When artificial channels constructed of PVC pipe were buried in the peat for 2 years, those filled with nutrient-rich organic matter had six times more roots than empty or sand-filled channels, indicating a response to greater nutrient availability rather than to greater space or less impedance to root growth. 4. Root proliferation inside decaying roots may improve recovery of nutrients released from decomposing tissues before they can be leached or immobilized in this intertidal environment. Greatest root proliferation in channels occurred in interior forest zones characterized by greater soil waterlogging, which suggests that this may be a strategy for nutrient capture that minimizes oxygen losses from the whole root system. 5. Improved efficiency of nutrient acquisition at the individual plant level has implications for nutrient economy at the ecosystem level and may explain, in part, how mangroves persist and grow in nutrient-poor environments.

Problematizando as práticas psicológicas no modo de compreender o fenômeno assédio moral

OpenAIRE

Meurer, Bruna; Strey, Marlene Neves

2012-01-01

O presente ensaio problematiza os discursos e estereótipos produzidos pelas ciências que incidem sobre homens e mulheres que praticam ou que são vítimas do assédio moral. Discute-se, assim, através de uma apreensão teórica sobre o fenômeno poder nas organizações, a possibilidade de uma reflexão crítica que permita o descolamento das condutas consideradas não morais, mas presentes no mundo do trabalho, do território normativo da patologização e da adaptação dos sujeitos. São realizadas reflexõ...

Efeitos da concentração dos compostos fenólicos no mosto da fermentação alcoólica

OpenAIRE

Henrique, Míriam Roberta [UNESP

2013-01-01

O objetivo deste trabalho foi avaliar a relação da concentração dos compostos fenólicos do mosto com a viabilidade celular, viabilidade de brotamento, brotamento celular da levedura alcoólica e a eficiência da fermentação por subprodutos durante a safra 2011/2012 na Usina São Manoel, São Manuel (SP). Esta unidade iniciou a safra com a levedura selecionada CAT-1. Durante a safra, as cepas nativas adentraram o processo fermentativo e também foram avaliadas quanto à sensibilidade a concentração ...

Species- and habitat-specific bioaccumulation of total mercury and methylmercury in the food web of a deep oligotrophic lake.

Science.gov (United States)

Arcagni, Marina; Juncos, Romina; Rizzo, Andrea; Pavlin, Majda; Fajon, Vesna; Arribére, María A; Horvat, Milena; Ribeiro Guevara, Sergio

2018-01-15

Niche segregation between introduced and native fish in Lake Nahuel Huapi, a deep oligotrophic lake in Northwest Patagonia (Argentina), occurs through the consumption of different prey. Therefore, in this work we analyzed total mercury [THg] and methylmercury [MeHg] concentrations in top predator fish and in their main prey to test whether their feeding habits influence [Hg]. Results indicate that [THg] and [MeHg] varied by foraging habitat and they increased with greater percentage of benthic diet and decreased with pelagic diet in Lake Nahuel Huapi. This is consistent with the fact that the native creole perch, a mostly benthivorous feeder, which shares the highest trophic level of the food web with introduced salmonids, had higher [THg] and [MeHg] than the more pelagic feeder rainbow trout and bentho-pelagic feeder brown trout. This differential THg and MeHg bioaccumulation observed in native and introduced fish provides evidence to the hypothesis that there are two main Hg transfer pathways from the base of the food web to top predators: a pelagic pathway where Hg is transferred from water, through plankton (with Hg in inorganic species mostly), forage fish to salmonids, and a benthic pathway, as Hg is transferred from the sediments (where Hg methylation occurs mostly), through crayfish (with higher [MeHg] than plankton), to native fish, leading to one fold higher [Hg]. Copyright © 2017 Elsevier B.V. All rights reserved.

Sources and sinks of nitrogen and phosphorus to a deep, oligotrophic lake, Lake Crescent, Olympic National Park, Washington

Science.gov (United States)

Moran, P.W.; Cox, S.E.; Embrey, S.S.; Huffman, R.L.; Olsen, T.D.; Fradkin, S.C.

2012-01-01

Lake Crescent, in Olympic National Park in the northwest corner of Washington State is a deep-water lake renowned for its pristine water quality and oligotrophic nature. To examine the major sources and sinks of nutrients (as total nitrogen, total phosphorus, and dissolved nitrate), a study was conducted in the Lake Crescent watershed. The study involved measuring five major inflow streams, the Lyre River as the major outflow, recording weather and climatic data, coring lake bed sediment, and analyzing nutrient chemistry in several relevant media over 14 months. Water samples for total nitrogen, total phosphorous, and dissolved nitrate from the five inflow streams, the outlet Lyre River, and two stations in the lake were collected monthly from May 2006 through May 2007. Periodic samples of shallow water from temporary sampling wells were collected at numerous locations around the lake. Concentrations of nutrients detected in Lake Crescent and tributaries were then applied to the water budget estimates to arrive at monthly and annual loads from various environmental components within the watershed. Other sources, such as leaf litter, pollen, or automobile exhaust were estimated from annual values obtained from various literature sources. This information then was used to construct a nutrient budget for total nitrogen and total phosphorus. The nitrogen budget generally highlights vehicle traffic-diesel trucks in particular-along U.S. Highway 101 as a potential major anthropogenic source of nitrogen compounds in the lake. In contrast, contribution of nitrogen compounds from onsite septic systems appears to be relatively minor related to the other sources identified.

Frequência de polimorfismos nos genes codificadores das enzimas 17βHSD5 e aromatase em mulheres com diferentes fenótipos da síndrome dos ovários policísticos e resposta ao tratamento com anticoncepcional oral

OpenAIRE

Polyana Sartori Maier

2012-01-01

A Síndrome dos Ovários Policísticos (PCOS) é a endocrinopatia mais frequente em mulheres na idade reprodutiva, além de ser a causa mais comum de hiperandrogenismo e anovulação crônica. Diferentes fenótipos da PCOS foram identificados, e um melhor entendimento dessas diferentes apresentações clínicas se faz necessário para o reconhecimento de riscos, medidas preventivas e terapêuticas específicas para cada fenótipo. Associações entre polimorfismos de substituição de um único nucleotídeo (SNPs)...

La fenêtre condamnée : Transparence et opacité de la représentation dans Les Rougon-Macquart d’Émile Zola

OpenAIRE

Piton-Foucault , Émilie ,

2012-01-01

TTransparent panes of glass and wide-open windows are some of the common models Zola’s critics have set up to emphasise the will of transitivity in his art. Although they denounce this idea as a literary utopia, it is still used as a pertinent key to understand Zolian fictional processes. La fenêtre condamnée questions the promotion of the “transparent window” to a metadiscursive symbol of Zolian transitivity by analysing its actualization in the Rougon- Macquart cycle. The study points out a...

O fenômeno recrutamento e seleção de enfermeiros em hospitais: um enfoque fenomenológico The phenomenon of recruitment and selecting nurses in the hospital: a phenomenon approach

Directory of Open Access Journals (Sweden)

Heloisa Helena Ciqueto Peres

1997-04-01

Full Text Available Este estudo teve como objetivo, desvelar o processo de recrutamento e seleção de enfermeiros a partir da experiência dos sujeitos que vi venciam essa prática. Para tanto buscou-se como trajetória metodológica a fenomenologia, na modal idade do fenômeno situado no referencial de Joel . Martins. Assim, o estudo foi realizado a partir do discurso de oito enfermeiros que experienciam o fenômeno. A análise dos depoimentos contemplou os momentos de descrição, redução e compreensão fenomenológicas, até o desvelamento da essencialidade do fenômeno investigado. Da análise fenomenológica dos discursos foi possível resgatar aspectos que representam a compreensão geral do processo de recrutamento e seleção de enfermeiros. Dessa forma, a essencialidade do fenômeno desvelado caracterizou-se pelas relações Homem, Organizações e Sociedade, relações essas de interdependência permeadas por múltiplos determinantes transituacionais. Nessa perspectiva, novos horizontes abriram-se no que tange o pensar recrutamento e seleção em enfermagem.This study had the purpose of showing the recruitment and selective process of nurses from their own experiences going through this process. The phenomenology was used as the methodological course, the phenomenon was based on the references by Joel Martins. The study was done from the speeches of eight nurses who went through the recruitment and selective process. The analysis of the speeches followed the moments of the phenomenological description, reduction and understanding until revealing the essence of the recruitment and selective process of nurses. From the phenomenological analysis of the speeches it was possible to get the aspects that represent the general understanding of the recruitment and selective process of nurses. In this way, the essence of the phenomenon was characterized by the relation among the man, the Company and the society, these relations were influenced by several

Postharvest Sensory and Phenolic Characterization of ‘Elegant Lady’ and ‘Carson’ Peaches Caracterización Fenólica y Sensorial en Poscosecha de Duraznos ‘Elegant Lady’ y ‘Carson’

Directory of Open Access Journals (Sweden)

Rodrigo Infante

2011-09-01

Full Text Available High quality fruits are increasingly demanded along with the need to ensure this attribute to consumers. Thus, this study was aimed at characterizing a melting (‘Elegant Lady’ and a non-melting flesh (‘Carson’ peach (Prunus persica (L. Batsch varieties by considering both their bioactive compound contribution and their sensory quality in ripe fruit at harvest and after a prolonged period of cold storage. Cultivars were evaluated at harvest (F0 and after 30 d of cold storage (F30, as well as after a maturation period at 20 °C for both F0 and F30 (R0 and R30, respectively. Fruit weight, flesh firmness, soluble solid content (SSC, titratable acidity (TA, and background color (Hue were recorded at each stage. Furthermore, total phenol content was measured and a phenolic characterization by HPLC (High-Performance Liquid Chromatography was performed for both varieties to detect the major low molecular weight phenolic compounds present in the fruit. Finally, a trained panel assessed the main sensorial parameters at R0 and R30. Total phenol content did not change significantly as a result of cold storage and differences were probably attributed only to genotype. Low molecular weight phenolic compounds were detected in ‘Elegant Lady’ and ‘Carson’, 15 and 12, respectively; (+-catechin was the major compound found in both cultivars, but in higher concentrations in ‘Elegant Lady’. In the phenolic characterization, ‘Elegant Lady’ was observed more closely than ‘Carson’ for flavonoids. After 30 d of cold storage, ‘Elegant Lady’ was unacceptable for consumption due to the appearance of physiological disorders such as wooliness while ‘Carson’ showed a mean score within the acceptability range.La demanda de fruta de alta calidad se ha incrementado junto con la necesidad de asegurar este atributo a los consumidores. En este sentido, el objetivo de este estudio fue caracterizar durazno (Prunus persica (L. Batsch de variedades

La consolidación del antihéroe como fenómeno en la ficción serial

Directory of Open Access Journals (Sweden)

Sara González Fernández

2016-05-01

Full Text Available Asesinos en serie(s es una obra colectiva en la que se aborda el fenómeno del serial killer desde una perspectiva multidisciplinar. En ella, Alberto Hermida y Víctor Hernández-Santaolalla coordinan el trabajo de veinte investigadores y profesores de diversos ámbitos del conocimiento, los cuales ofrecen todas las claves necesarias para comprender los aspectos que se ocultan y que, a su vez, posibilitan la representación del asesino en la ficción televisiva. Dexter, Hannibal, Bates Motel, True Detective o The Following, son algunas de las exitosas series de referencia en las que se adentra este volumen para analizar exhaustivamente aspectos como la representación, las relaciones y el perfil psicopático de este personaje en la ficción serial.

Análise da utilização na prática dos termos atribuídos aos fenômenos de enfermagem da CIPE-Versão Alfa

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Maria Miriam Lima da Nóbrega

2001-09-01

Full Text Available Este estudo teve como propósito a análise da utilização dos termos atribuídos aos fenômenos de enfermagem na prática das enfermeiras paraibanas. Os resultados evidenciam que todos os termos são utilizados pelas enfermeiras, com alguma freqüência. No que diz respeito à utilização dos termos, de acordo com o estrato amostral, os resultados evidenciam que as enfermeiras dos demais Municípios Paraibanos utilizam um maior número de termos, estatisticamente significativo, quando comparado com os dois outros estratos - João Pessoa e Campina Grande. A partir dos resultados do estudo, pode-se concluir, que os termos atribuídos aos fenômenos constantes na CIPE - Versão Alfa representam problemas ou situações da prática de enfermagem das enfermeiras paraibanas, corroborando a afirmação do Conselho Internacional de Enfermeiras de que estes termos são comuns às enfermeiras de todo o mundo.

A multiproxy study of Holocene water-depth and environmental changes in Lake St Ana, Eastern Carpathian Mountains, Romania

Science.gov (United States)

Magyari, E. K.; Buczkó, K.; Braun, M.; Jakab, G.

2009-04-01

This study presents the results of a multi-disciplinary investigation carried out on the sediment of a crater lake (Lake Saint Ana, 950 m a.s.l.) from the Eastern Carpathian Mountains. The lake is set in a base-poor volcanic environment with oligotrophic and slightly acidic water. Loss-on-ignition, major and trace element, pollen, plant macrofossil and siliceous algae analyses were used to reconstruct Holocene environmental and water-depth changes. Diatom-based transfer functions were applied to estimate the lake's trophic status and pH, while reconstruction of the water-depth changes was based on the plant macrofossil and diatom records. The lowest Holocene water-depths were found between 9,000 and 7,400 calibrated BP years, when the crater was occupied by Sphagnum-bog and bog-pools. The major trend from 7,400 years BP was a gradual increase, but the basin was still dominated by poor-fen and poor fen-pools. Significant increases in water-depth, and meso/oligotrophic lake conditions were found from 5,350(1), 3,300(2) and 2,700 years BP. Of these, the first two coincided with major terrestrial vegetation changes, namely the establishment of Carpinus betulus on the crater slope (1), and the replacement of the lakeshore Picea abies forest by Fagus sylvatica (2). The chemical record clearly indicated significant soil changes along with the canopy changes (from coniferous to deciduous), that in turn led to increased in-lake productivity and pH. A further increase in water-depth around 2,700 years BP resulted in stable thermal stratification and hypolimnetic anoxia that via P-release further increased in-lake productivity and eventually led to phytoplankton blooms with large populations of Scenedesmus cf. S. brasiliensis. High productivity was depressed by anthropogenic lakeshore forest clearances commencing from ca. 1,000 years BP that led to the re-establishment of Picea abies on the lakeshore and consequent acidification of the lake-water. On the whole, these data

Polpa de juçara: fonte de compostos fenólicos, aumento da atividade antioxidante e da viabilidade de bactérias probióticas de iogurte

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Sabrina Torres Leite

Full Text Available RESUMO A adição, em iogurtes, de polpa de Juçara como fonte de compostos fenólicos pode modificar as características físico-químicas, contribuir para atividade antioxidante, e interferir na viabilidade de bactérias probióticas e na aceitação sensorial. Com o objetivo de verificar o efeito da adição de polpa de Juçara em iogurte, foi realizado um experimento, em delineamento inteiramente casualizado, em parcelas subdivididas. A parcela principal foi o teor de polpa, com seis níveis (0, 5, 10, 15, 20 e 25% e, como subparcela, o tempo de armazenamento, a 5 oC, com cinco níveis (1, 7, 14, 21 e 28 dias. Os teores percentuais médios de gordura, cinzas, extrato seco total e acidez dos iogurtes não diferiram (P ≥ 0,05. O teor de proteína diminuiu com o aumento do teor de polpa, variando de 4,07% (F0 a 2,9% (F25%. O conteúdo fenólico total e a atividade antioxidante foram maiores no iogurte com 25% de polpa, atingindo valores de 117,84 mg de AGE/100g e 6,95 µmol Trolox/g, respectivamente, assim como a contagem de bactérias probióticas, que variou de 3,17 log UFC.g-1 (F0 a 6,34 log UFC.g-1 (F25%, nos iogurtes, após 28 dias de armazenamento. A adição da polpa de Juçara favoreceu a multiplicação e a viabilidade de bactérias probióticas, contribuiu para o aumento do conteúdo fenólico total e para maior atividade antioxidante dos iogurtes, que apresentaram boa aceitação sensorial pelo consumidor.

Variables asociadas con el fenómeno de la deserción de los estudiantes en la Fundación Universitaria Konrad Lorenz

OpenAIRE

Barrero, Johanna; Garzón, Gustavo; Gómez, Óscar

2013-01-01

Los avances investigativos sobre deserción reflejan múltiples variables causales de dicho fenómeno, variables sociales, económicas y académicas, entre otras. No existen perfiles definidos para describir y explicar con precisión la forma en que se comportan cada una de estas variables por la heterogeneidad de población. La presente investigación, cuyo objetivo general fue identificar las variables sociodemográficas, financieras y académicas relacionadas con la deserción de los estudiantes en l...

Estudio del fenómeno de plastificación en los túneles de O Cañizo, L.A.V. Madrid-Galicia

OpenAIRE

2015-01-01

Los túneles de O Cañizo, situados en A Gudiña (Ourense), forman parte de la LAV Madrid – Galicia tramo Lubián-Ourense, actualmente en construcción. Estos túneles perforan materiales igneos y metasedimentarios, transcurriendo una importante zona de falla (falla de Pentes) en el contacto entre ambos. En esta tesis se procede al estudio del fenómeno de plastificación observado en la perforación al atravesar la zona de falla. La plastificación o squeezing suele producirse generalmente durante ...

Modelación de fenómenos metalúrgicos en laminación en caliente de acero

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Zambrano, P.

2008-02-01

Full Text Available Modelling of hot rolling of steel strip involves metallurgical phenomena such as restoration of deformed structures, transformation to ferrite and growth of the oxide layer on top of the steel strip. The effect of composition is taken into account when restoration and phase transformation is considered, whereas it is assumed that the chemical composition of the steel substrate does not affect the oxide crust, being common place to consider the oxide just as a thermal barrier and to assume sticking conditions within the roll-gap. Observations indicate that elements such as silicon and manganese, more susceptible to oxidize than iron, affect the growth kinetics, adhesion and the behaviour during deformation of the oxide layer. This work deals with the way used to model various superficial and metallurgical phenomena, and how this knowledge is used to simulate hot rolling of steel strip.

La modelación del proceso de laminación en caliente de acero incorpora fenómenos metalúrgicos como son la restauración de la estructura deformada, la trasformación de fase y el crecimiento de la capa de óxido sobre la superficie del acero. Se reconoce el efecto de la composición química sobre la transformación de fase y la restauración, sin embargo se considera que el crecimiento del óxido no es afectado por la presencia de elementos aleantes en el acero y es común que se maneje a la costra de óxido como una barrera térmica y que se supongan condiciones de fricción adhesivas en el entrehierro. Determinadas observaciones indican que elementos como el silicio y el manganeso, más susceptibles a oxidarse que el hierro, afectan la cinética de crecimiento, la adhesión y el comportamiento de la costra al ser deformada. En este trabajo se presenta la forma en que diversos fenómenos metalúrgicos y de superficie se modelan y se utilizan para simular el proceso de laminación en caliente.

How do Bacteria Adapt to the Red Sea? Cultivation and Genomic and Physiological Characterization of Oligotrophic Bacteria of the PS1, OM43, and SAR11 Clades

KAUST Repository

Jimenez Infante, Francy M.

2015-05-01

Given the high salinity, prevailing annual high temperatures, and ultra-oligotrophic conditions in the Red Sea isolation and characterization of important microbial groups thriving in this environment is important in understanding the ecological significance and metabolic capabilities of these communities. By using a high-­throughput cultivation technique in natural seawater amended with minute amounts of nutrients, members of the rare biosphere (PS1), methylotrophic Betaproteobacteria (OM43), and the ubiquitous and abundant SAR11 group (Pelagibacterales), were isolated in pure culture. Phylogenetic analyses of Red Sea isolates along with comparative genomics with close representatives from disparate provinces revealed ecotypes and genomic differentiation among the groups. Firstly, the PS1 alphaproteobacterial clade was found to be present in very low abundance in several metagenomic datasets form divergent environments. While strain RS24 (Red Sea) harbored genomic islands involved in polymer degradation, IMCC14465 (East (Japan) Sea) contained unique genes for degradation of aromatic compounds. Secondly, methylotrophic OM43 bacteria from the Red Sea (F5, G12 and H7) showed higher similarities with KB13 isolate from Hawaii, forming a ‘H-­RS’ (Hawaii-­Red Sea) cluster separate from HTCC2181 (Oregon isolate). HTCC2181 members were shown to prevail in cold, productive coastal environments and had an nqrA-­F system for energy generation by sodium motive force. On the contrary, H-­RS cluster members may be better adapted to warm and oligotrophic environments, and seem to generate energy by using a proton-­translocating NADH:Quinone oxidoreductase (complex I; nuoA-­N subunits). Moreover, F5, G12, and H7 had unique proteins related to resistance to UV, temperature and salinity, in addition to a heavy metal ‘resistance island’ as adaptive traits to cope with the environmental conditions in the Red Sea. Finally, description of the Red Sea Pelagibacterales

Irmandade afetada pela atrofia muscular peroneal de Charcot-Marie-Tooth com possível variante do fenômeno da antecipação

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Aguinaldo Gonçalves

1977-06-01

Full Text Available Considerando-se a peculiaridade genética da atrofia peroneal de Charcot-Marie-Tooth, é feita a descrição clínica de família com três irmãos afetados, com idade de aparecimento progressivamente antecipada, refletindo possível variante do fenômeno da antecipação, condição inusitada na literatura, não só para esta doença, mas também, de modo geral, em Genética Humana.

Seasonal variation in the phenol content of Eugenia uniflora L. leaves Variação sazonal nos teores de fenóis de folhas de Eugenia uniflora L

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R.M Santos

2011-01-01

Full Text Available Hydrolysable tannins, total phenols and flavonoids in Eugenia uniflora leaves were monthly analysed for one year. The results were correlated with climate conditions (rainfall, humidity, cloudiness and mean temperature through chemometric methods. Principal component analysis revealed high levels of hydrolysable tannins in the rainy season, whereas flavonoids were mainly produced in the dry season. These facts suggest that climatic changes may be one of the factors affecting phenol levels in Eugenia uniflora.Taninos hidrolisáveis, fenóis totais e flavonóides presentes em folhas de Eugenia uniflora foram quantificados mensalmente durante um ano. Os resultados foram correlacionados com as condições climáticas (pluviosidade, umidade, nebulosidade e temperatura média através de métodos quimiométricos. Análise de componentes principais revelou a ocorrência de altos teores de taninos hidrolisáveis durante a estação de chuvas, enquanto os flavonóides foram produzidos principalmente na estação seca. Estes fatos sugerem que mudanças climáticas podem ser um dos fatores que afetam os níveis de fenóis em Eugenia uniflora.

A gestão de cursos de graduação a distância e o fenômeno da evasão = Management distance education courses and phenomenon of dropout

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Daudt, Sônia Isabel Dondonis

2013-01-01

Full Text Available Este artigo traz considerações a respeito dos aspectos envolvidos na gestão de cursos de graduação a distância. Apresenta um estudo bibliográfico que mostra características e fatores envolvidos na gestão de cursos a distância em universidades brasileiras e o fenômeno da evasão, neste contexto. As formas de acesso e permanência dos alunos em cursos desta modalidade têm-se mostrado um grande desafio para os pesquisadores e gestores das Instituições de Ensino Superior (IES. O artigo discute dimensões importantes a considerar na gestão dos cursos, quando se busca enfrentar a evasão universitária em cursos on-line, um dos fenômenos que mais atinge, preocupa e desafia essa modalidade de ensino. Conclui pela relevância da comunicação afetiva entre estudantes, professores e tutores

Fen Bilimleri Öğretmen Adaylarının Çevre Sorunlarına Yönelik Tutumları ve Çevre Kirliliğine Yönelik Metaforik Algıları

OpenAIRE

ARIK, Selçuk; YILMAZ, Mehmet

2017-01-01

Bu çalışmanın amacı, fen bilimleri öğretmen adaylarının çevre sorunlarına yöneliktutumlarını ve çevre kirliliğine yönelik metaforik algılarını araştırmaktır. Araştırma 2013-2014eğitim öğretim yarıyılı güz döneminde Tokat Gaziosmanpaşa Üniversitesinde gerçekleştirilmiştir.Araştırmanın, çalışma grubunu fen bilimleri öğretmen adayları (n=132) oluşturmuştur.Araştırmada verileri toplamak amacıyla “Çevre Tutumları Ölçeği”(Yoldaş, 2009) ve metafortoplama formu kullanılmıştır. Bu araştırma da nicel a...

Control of brown spot pathogen of rice (Bipolaris oryzae using some phenolic antioxidants Controle da macha-parda do arroz (Bipolaris oryzae pelo emprego de antioxidantes fenólicos

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Y.M. Shabana

2008-09-01

Full Text Available Bipolaris oryzae is the causal agent of rice brown spot disease and is responsible for significant economic losses. In order to control this disease, three phenolic antioxidants were tested (salicylic acid, benzoic acid and hydroquinone. The antifungal activity of the tested substances were investigated against B. oryzae at different concentrations in vitro, as well as the efficacy of their exogenous application in controlling rice brown spot disease under field conditions. In vitro, benzoic acid or salicylic acid at 9 mM completely inhibited the growth of B. oryzae. Under field conditions, spraying of benzoic acid at 20 mM led to a significant reduction in disease severity (DS and disease incidence (DI on the plant leaves, in addition to a significant increase in the grain yield and its components. Some biochemical responses were also detected, where the application of the previous treatment led to a significant increase in the total photosynthetic pigments (chlorophyll a and b and carotenoids in rice leaves and in the total carbohydrate and protein contents of the yielded grains.Bipolaris oryzae é o agente causador da doença mancha-parda do arroz e é responsável por significativas perdas econômicas. Três antioxidantes fenólicos (ácido salicílico, ácido benzóico e hidroquinona foram avaliados para o controle dessa doença do arroz. A atividade antifúngica destes compostos foi avaliada in vitro contra B. oryzae em diferentes concentrações e a eficiência de sua aplicação exógena no controle da mancha-parda foi avaliada em condições de campo. Nos ensaios in vitro, os ácidos benzóico e salicílico a 9 mM inibiram completamente a multiplicação de B. oryzae. Em condições de campo, a aspersão de ácido benzóico a 20 mM causou uma redução significativa na gravidade e incidência da doença na folhas da planta, além de aumentar significativamente o rendimento dos grãos e seus componentes. Algumas respostas bioqu

Effect of phenolic extracts on trans fatty acid formation during frying

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Gamel, TH

1999-12-01

Full Text Available Olive oil (blend of refined and virgin and sunflower oil containing added methanol phenolic extracts of dry rosemary and olive vegetable water or the synthetic antioxidant BHA in combination with the extracts, were used in a frying process. Eight frying operations were performed at 180 °C with 24 hr intervals between fryings. During the frying period the trans fatty acids (TFA by capillary column gas chromatography (CC-GC were determined. Trans fatty acids of oleic and linoleic were increased with frying time in both the control oil samples. The rosemary additives (extracts alone and in combination with BHA decreased the level of trans fatty acids (mainly elaidic acid, while the addition of olive vegetable water did not have any effect.

Aceite de oliva (mezcla de virgen y refinado y aceite de girasol con extractos fenólicos de romero seco y aguas de vegetación de aceituna, o con el antioxidante sintético BHA en combinación con los extractos, se usaron en proceso de fritura. Se realizaron 8 operaciones de fritura a 180°C con intervalos de 24 h. Se determinaron los ácidos grasos trans (TFA por cromatografía de gases en columna capilar (CC-GC. Los ácidos grasos trans de oleico y linoleico aumentaron con el tiempo de fritura en las muestras de aceite control. Los extractos de romero, solos y en combinación con BHA, disminuyeron los niveles de ácidos grasos trans (principalmente ácido elaídico mientras que la adicción de aguas de vegetación de aceituna no tuvo ningún efecto.

The climate warming effect of a fen peat meadow with fluctuating water table is reduced by young alder trees

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V. Huth

2018-03-01

Full Text Available Black alder (Alnus glutinosa (L. Gaertn. occurs naturally in temperate marshes and in minerotrophic peatlands and is also suitable for paludiculture - the cultivation of biomass on wet or rewetted peatland. We investigated the effect of a newly established black alder plantation on the greenhouse gas (GHG balance of a degraded fen in north-eastern Germany over a two-year period (August 2010–August 2012. We compared the alder plantation (Awet with an extensively used meadow (Mwet and a drier reference meadow (Mmoist. GHG fluxes were measured monthly to bi-monthly using the closed chamber method. Our results show that Awet was a slight net GHG (in CO2-eq sink of 3.4 ± 1.7 t ha-1 yr-1, Mwet was a moderate net GHG source of 9.6 ± 1.2 t ha 1 yr-1, and Mmoist was a strong net GHG source of 24.5 ± 1.6 t ha-1 yr-1. This was mainly driven by CO2 uptake at the two very moist (wet sites and by high CO2 release at the drier reference site. Awet was a larger CO2 sink than Mwet, probably due to additional CO2 uptake by the alder stand at Awet and carbon export in plant material harvested from Mwet. All sites were significant CH4 sources. Substantial CH4 emission peaks were observed at all sites following extraordinarily heavy precipitation during the summer of 2011, which accounted for up to 70 % of the accumulated two-year CH4 emissions. However, the Awet site generally emitted less CH4, possibly due to the effective oxygen transport mechanism in black alders. N2O emissions were negligible at all three sites. Our results indicate that the GHG balances of formerly drained fens benefit in the short term from planting of black alders, mostly due to reduced CH4 emissions. This study highlights the importance of acknowledging extreme precipitation events and groundwater fluctuations for the derivation of reliable GHG emission factors.

AMS radiocarbon analyses from Lake Baikal, Siberia: Challenges of dating sediments from a large, oligotrophic lake

Science.gov (United States)

Colman, Steven M.; Jones, Glenn A.; Rubin, M.; King, J.W.; Peck, J.A.; Orem, W.H.

1996-01-01

A suite of 146 new accelerator-mass spectrometer (AMS) radiocarbon ages provides the first reliable chronology for late Quaternary sediments in Lake Baikal. In this large, highly oligotrophic lake, biogenic and authigenic carbonate are absent, and plant macrofossils are extremely rare. Total organic carbon is therefore the primary material available for dating. Several problems are associated with the TOC ages. One is the mixture of carbon sources in TOC, not all of which are syndepositional in age. This problem manifests itself in apparent ages for the sediment surface that are greater than zero. However, because most of the organic carbon in Lake Baikal sediments is algal (autochthonous) in origin, this effect is limited to about 1000+500 years, which can be corrected, at least for young deposits. The other major problem with dating Lake Baikal sediments is the very low carbon contents of glacial-age deposits, which makes them extremely susceptible to contamination with modern carbon. This problem can be minimized by careful sampling and handling procedures. The ages show almost an order of magnitude difference in sediment-accumulation rates among different sedimentary environments in Lake Baikal, from about 0.04 mm/year on isolated banks such as Academician Ridge, to nearly 0.3 mm/year in the turbidite depositional areas beneath the deep basin floors, such as the Central Basin. The new AMS ages clearly indicate that the dramatic increase in diatom productivity in the lake, as evidenced by increases in biogenic silica and organic carbon, began about 13 ka, in contrast to previous estimates of 7 ka for the age of this transition. Holocene net sedimentation rates may be less than, equal to, or greater than those in the late Pleistocene, depending on the site. This variability reflects the balance between variable terrigenous sedimentation and increased biogenic sedimentation during interglaciations. The ages reported here, and the temporal and spatial variation in

Incidencia de la ley anti maras en el fenómeno de las maras en El Salvador período de estudio: 2003-2010

OpenAIRE

Botta Serrano, Marianella

2012-01-01

La aplicación de la ley anti maras en El Salvador no tuvo los resultados esperados por el gobierno en el momento de su implementación, la reducción del fenómeno no se vio afectada por la aplicación de esta ley que al contrario produjo una serie de efectos negativos que demostraron tanto la inefectividad de dicha ley, como la capacidad de las maras para adaptarse y evolucionar frente a las adversidades que les presentó una medida represiva como la tomada por el gobierno salvadoreño.

Polimorfismos no SNP CGIL4: estudo de associação ao fenótipo de resistência a mastite clinica em vacas holandesas

OpenAIRE

Molina, Rachel Dias; Univates; Kich, Débora Mara; Univates; Vendramin, Tatiane; Univates; Souza, Claucia Fernanda Volken de; Univates; Lehn, Daniel Neutzling; Univates; Pozzobon, Adriane; Univates; Bustamante-Filho, Ivan Cunha; Univates

2014-01-01

A mastite bovina é a principal patologia da glândula mamária e a maior causadora de prejuízos na produção leiteira. Sua etiologia é quase sempre relacionada a problemas de manejo sanitário e de ordenha. Entretanto, observa-se a existência de animais com maior ou menor resistência a mastite, mesmo quando fatores ambientais são controlados. Recentemente, alguns marcadores moleculares foram associados ao fenótipo de resistência a mastite. O presente estudo teve como objetivo verificar se com bas...

Influência do sombreamento sobre os teores de carboidratos e fenóis em estacas semilenhosas de araçazeiro Influence of shading on the carbohydrates and phenols in cattley guava cutting

Directory of Open Access Journals (Sweden)

João Guilherme Casagrande Junior

1999-12-01

Full Text Available O presente trabalho teve por objetivo avaliar a influência do sombreamento sobre os teores de carboidratos não-estruturais e fenóis solúveis totais em folhas e caules de estacas de plantas matrizes de araçazeiro (Psidium cattleyanum Sabine. Foram coletadas estacas semilenhosas em novembro de 1996, de plantas mantidas sob diferentes níveis de sombreamento (utilizou-se sombrite com malha comercial de 30, 50 e 70% de redução da luz e de plantas mantidas a pleno sol. Os teores de carboidratos solúveis totais, redutores, amido e fenóis solúveis totais foram determinados nas folhas e no caule de cada estaca. Com o aumento do sombreamento, observou-se uma elevação dos teores de amido e uma redução nos teores de carboidratos redutores nas folhas e no caule e, apenas no caule, uma redução dos carboidratos solúveis totais. Os compostos fenólicos foram reduzidos significativamente nas folhas, à medida que se aumentou a porcentagem de sombreamento, ao passo que nos caules verificou-se uma redução, mas pouco pronunciada, ratificando a afirmação de que plantas submetidas a condições de baixa radiação solar alteram seus teores de compostos de reserva e fenóis.The present work proposed to evaluate the influence of shading on the non-structural carbohydrates and total soluble phenols in leaves and stem of cutting, collected from cattley guava (Psidium cattleyanum Sabine stock plant. The half-wood cuttings were collected in November of 1996, in plants kept under different shading levels (30, 50 e 70% of reducing light and plants kept full sun. The content of total and reducing soluble carbohydrates, starch and total soluble phenols were determined on the leaves and on the stem of each cutting. It was observed that with the increase of shading, there was a raise on starch content and a decrease on reducing carbohydrates content both on leaves and stems. Only on the stem a decrease on total soluble carbohydrates content was observed

Magnetization switching behavior with competing anisotropies in epitaxial Co3FeN /MnN exchange-coupled bilayers

Science.gov (United States)

Hajiri, T.; Yoshida, T.; Jaiswal, S.; Filianina, M.; Borie, B.; Ando, H.; Asano, H.; Zabel, H.; Kläui, M.

2016-11-01

We report unusual magnetization switching processes and angular-dependent exchange bias effects in fully epitaxial Co3FeN /MnN bilayers, where magnetocrystalline anisotropy and exchange coupling compete, probed by longitudinal and transverse magneto-optic Kerr effect (MOKE) magnetometry. The MOKE loops show multistep jumps corresponding to the nucleation and propagation of 90∘ domain walls in as-grown bilayers. By inducing exchange coupling, we confirm changes of the magnetization switching process due to the unidirectional anisotropy field of the exchange coupling. Taking into account the experimentally obtained values of the fourfold magnetocrystalline anisotropy, the unidirectional anisotropy field, the exchange-coupling constant, and the uniaxial anisotropy including its direction, the calculated angular-dependent exchange bias reproduces the experimental results. These results demonstrate the essential role of the competition between magnetocrystalline anisotropy and exchange coupling for understanding and tailoring exchange-coupling phenomena usable for engineering switching in fully epitaxial bilayers made of tailored materials.

Influencia del fenómeno ENOS (El Niño y La Niña) en la disponibilidad de grados-día

OpenAIRE

Lozada García, Beatriz; Prela, Angélica; Sentelhas, Paulo

2004-01-01

Se evaluó la influencia del fenómeno ENOS (El Niño y La Niña) sobre la disponibilidad de calor, en 8 localidades, ubicadas en la región centro-occidental de Venezuela, utilizando concepto de grados-día (GD). Los cambios de la temperatura, representados por las variaciones en los GD, afectarían directamente el ciclo fenológico los cultivos, generando un incremento o reducción en función de desvíos positivos o negativos, respectivamente. Los GD estimados fueron agrupados según el evento predomi...

Sobre los saberes culturales y el fenómeno "sentirse bien-sentirse mal" On cultural knowledge and the phenomenon "feel good-fell bad"

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Virtudes Rodero Sánchez

2010-09-01

Full Text Available El objetivo del presente estudio es identificar los saberes culturales inmersos en el fenómeno "sentirse-bien, sentirse mal", en diferentes situaciones de cuidado. Se elaboró un estudio cualitativo con un enfoque fenomenológico interpretativo, mediante el análisis de 18 narrativas a partir de entrevistas en profundidad realizadas por alumnas del Máster en Ciencias de la Enfermería en diferentes contextos de cuidados. Las categorías identificadas fueron: (1 Cronicidad y concepto de sentirse bien-sentirse mal. En la cronicidad este concepto está íntimamente relacionado con la recuperación de las actividades de la vida diaria y es componente importante en la percepción individual del concepto "calidad de vida". (2 Momentos agudos de enfermedad y concepto de sentirse bien-sentirse mal. En el análisis de los relatos del paciente aparecieron aspectos esenciales del fenómeno "sentirse bien-sentirse mal" para aumentar la comprensión de aspectos universales de algunos de sus componentes. Destacar que el fenómeno está íntimamente relacionado con la recuperación de las actividades de la vida diaria, y es un mediador importante en la percepción individual del concepto "calidad de vida". El interés de cara al cuidado es distinguir sus componentes universales, contextualizarlos en la práctica, dentro de las singularidades que presenta cada persona, de modo que nos permita su potenciación. El resultado es un cambio en la experiencia sentida.The object of the present study is to identify cultural knowledges immersed in the feeling-well, feeling-bad phenomenon in different care settings. A qualitative study was undertaken using a phenomenological interpretation approach through a meta-analysis of 18 narratives of profound interviews undertaken by Nursing Science Master Degree Students in different care situations. The categories established were: (1 Chronicity and the concept of feeling well-feeling bad. In this category, this concept is

O fenômeno da globalização e o novo cenário dos atores das relações internacionais

OpenAIRE

Olsson, Giovanni

2001-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Jurídicas O presente estudo envolve-se com temas de Relações Internacionais e Globalização. Na sua abordagem, procura analisar de que forma as relações internacionais estão sendo atingidas pelo fenômeno da globalização no mundo contemporâneo, com as alterações no cenário dos seus atores e na redefinição da sociedade internacional, em vista da emergência de uma sociedade mundializada. A investigação científ...

Biodiversity patterns of crustacean suprabenthic assemblages along an oligotrophic gradient in the bathyal Mediterranean Sea

Science.gov (United States)

Almeida, Mariana; Frutos, Inmaculada; Tecchio, Samuele; Lampadariou, Nikolaos; Company, Joan B.; Ramirez-Llodra, Eva; Cunha, Marina R.

2017-03-01

Crustacean suprabenthic abundance, community structure, α-diversity (both taxonomic and trophic) and β-diversity were studied along a West-East gradient of oligotrophy in the deep Mediterranean Sea. The assemblages were sampled with a suprabenthic sledge in three regions (western, central and eastern basins) at three water depths (1200, 2000 and 3000 m) in May-June 2009. Environmental data were obtained at each sampling location including sediment properties, oceanographic variables near the seafloor and in the water column, and proxies of epipelagic productivity at the surface. Our results, concerning the crustacean component of the suprabenthos, showed complex trends in community structure and biodiversity across different spatial scales (longitudinal, bathymetric, and near-bottom distribution). A decrease in the number of species and abundance, accompanied by changes in the trophic structure of the assemblages were observed from West to East. In the eastern region the assemblages were impoverished in number of trophic guilds and trophic diversity. The West-East oligotrophic gradient was identified as the main driver in community structure as shown by the significant correlation with trophic environmental variables. Differences in community structure across regions were more marked at greater depths, while at the shallower sites assemblages were more similar. Within each basin, abundance, number of species and number of trophic groups decreased with depth, showing high turnover rates between 1200 and 2000 m depths. The small-scale (0-150 cm) vertical distribution of the suprabenthos was interpreted in relation to the species' functional traits (e.g. swimming activity, migratory behaviour, bottom dependence, feeding habits). Bottom-dependent and more mobile components of the suprabenthos were apparently responding differently to the various environmental challenges imposed by the large-scale longitudinal and bathymetric gradients. We propose that the bathyal

Acoso sexual: Elementos de discusión para la redefinición del fenómeno

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Víctor Manuel Aguilar Pereira

2007-02-01

Full Text Available LA PROBLEMÁTICA DEL ACOSO SEXUAL SE HA CONFINADO, GENERALMENTE, al ámbito laboral, y se ha considerado como un efecto de relaciones jerárquicas. Esta concepción ha limitado su estudio en cierta medida, y ha permitido que se ignoren otras manifestaciones, mucho más sutiles, pero que, con una mirada más minuciosa y crítica, dejan entrever los cimientos socio-históricos de este fenómeno: la arraigada ideología de género, traducida en violencia de género, que mancilla diariamente los derechos fundamentales de la mujer. Si bien falta un largo camino por recorrer para reformular una definición integral de acoso sexual, los factores aquí presentados se han considerado elementos primordiales para esta reformulación, puesto que permitirán un conocimiento más amplio de las raíces que sustentan al acoso sexual, lo que a su vez encaminará propuestas de acción efectivas para que, tanto hombres como mujeres, puedan hacerle frente.

Estudio exploratorio sobre el fenómeno del “Bullying” en la ciudad de Cali, Colombia

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María Teresa Paredes

2008-05-01

Full Text Available Este es el primer estudio sobre el fenómeno del hostigamiento entre pares o “bullying” que se realiza en la ciudad de Cali, Colombia. Se efectuaron 2.542 encuestas a estudiantes de sexto, séptimo y octavo grados de catorce colegios de la ciudad, con el fin de identificar la presencia del problema y –en caso de existir– de establecer las formas específicas de manifestación, teniendo en cuenta edad, género y estrato socioeconómico.Los resultados demostraron la presencia de “bullying” en el 24.7% de los encuestados y encuestadas, expresado en comportamientos de intimidación o agresión verbal, física y psicológica en estudiantes de ambos géneros de todos los estratos socioeconómicos. Se estableció que la forma de agresión de mayor frecuencia es la verbal y que ésta sucede también en presencia de otros compañeros, compañeras, profesoras y profesores en el aula de clase.

Guided Image Filtering-Based Pan-Sharpening Method: A Case Study of GaoFen-2 Imagery

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Yalan Zheng

2017-12-01

Full Text Available GaoFen-2 (GF-2 is a civilian optical satellite self-developed by China equipped with both multispectral and panchromatic sensors, and is the first satellite in China with a resolution below 1 m. Because the pan-sharpening methods on GF-2 imagery have not been a focus of previous works, we propose a novel pan-sharpening method based on guided image filtering and compare the performance to state-of-the-art methods on GF-2 images. Guided image filtering was introduced to decompose and transfer the details and structures from the original panchromatic and multispectral bands. Thereafter, an adaptive model that considers the local spectral relationship was designed to properly inject spatial information back into the original spectral bands. Four pairs of GF-2 images acquired from urban, water body, cropland, and forest areas were selected for the experiments. Both quantitative and visual inspections were used for the assessment. The experimental results demonstrated that for GF-2 imagery acquired over different scenes, the proposed approach consistently achieves high spectral fidelity and enhances spatial details, thereby benefitting the potential classification procedures.

Leaf-litter microfungal community on poor fen plant debris in Torfy Lake area (Central Poland

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Mateusz Wilk

2014-06-01

Full Text Available The purpose of this study was to initially evaluate the species diversity of microfungi growing on litter of 15 plant species occurring on the poor fen and neighbouring area of the Torfy Lake, Masovian voivodeship, Poland. The lake is located near the planned road investment (construction of the Warsaw southern express ring road S2. The place is biologically valuable as there are rare plant communities from Rhynchosporion albae alliance protected under the Habitats Directive adopted by the European Union. On the examined plant debris 73 taxa of fungi were recorded (3 basidiomycetes, 13 ascomycetes, 2 zygomycetes, 43 anamorphic ascomycetes, 12 unidentified. Two of them, Dicranidion sp. and Wentiomyces sp. are presented here as new to Poland. Among the plant species examined, the litter of Rhododendron tomentosum harbored the highest number of fungal taxa (16. The highest percents of substrate-specific microfungi (i.e. recorded only on one plant species was noted on R. tomentosum (81.3 %, and Pteridium aquilinum (75%. It is emphasized that the lake area should be protected not only because of rare plant community but also because of the uniqueness and diversity of mycobiota.

The use of amino acid indices for assessing organic matter quality and microbial abundance in deep-sea Antarctic sediments of IODP Expedition 318

Science.gov (United States)

Carr, Stephanie A; Mills, Christopher T.; Mandernack, Kevin W

2016-01-01

The Adélie Basin, located offshore of the Wilkes Land margin, experiences unusually high sedimentation rates (~ 2 cm yr− 1) for the Antarctic coast. This study sought to compare depthwise changes in organic matter (OM) quantity and quality with changes in microbial biomass with depth at this high-deposition site and an offshore continental margin site. Sediments from both sites were collected during the International Ocean Drilling (IODP) Program Expedition 318. Viable microbial biomass was estimated from concentrations of bacterial-derived phospholipid fatty acids, while OM quality was assessed using four different amino acid degradation proxies. Concentrations of total hydrolysable amino acids (THAA) measured from the continental margin suggest an oligotrophic environment, with THAA concentrations representing only 2% of total organic carbon with relative proportions of non-protein amino acids β-alanine and γ-aminobutyric acid as high as 40%. In contrast, THAA concentrations from the near-shore Adélie Basin represent 40%–60% of total organic carbon. Concentrations of β-alanine and γ-aminobutyric acid were often below the detection limit and suggest that the OM of the basin as labile. DI values in surface sediments at the Adélie and margin sites were measured to be + 0.78 and − 0.76, reflecting labile and more recalcitrant OM, respectively. Greater DI values in deeper and more anoxic portions of both cores correlated positively with increased relative concentrations of phenylalanine plus tyrosine and may represent a change of redox conditions, rather than OM quality. This suggests that DI values calculated along chemical profiles should be interpreted with caution. THAA concentrations, the percentage of organic carbon (CAA%) and total nitrogen (NAA%) represented by amino acids at both sites demonstrated a significant positive correlation with bacterial abundance estimates. These data suggest that the selective degradation of amino acids, as

Producción y caracterización de biocatalizadores implicados en la obtención de ácido siálico y compuestos relacionados = Production and characterization of biocatalysts involved in obtaining sialic acid and related compounds.

OpenAIRE

García García, María Inmaculada

2012-01-01

Palabras claves: Enzymes Biocatalysts N-acetyl neuraminte lyase N-acetyl neuraminate synthase Sialic acid Kinetic parameters CLEAs GRAS microorganism Aldolase Protein Cloning N-acetyl-D-mannosamine Pyruvate Resumen El ácido siálico y sus derivados son un grupo importante de biomoléculas implicadas en muchos fenómenos biológicos. Su síntesis y aplicación es de gran interés en la industria farmacéutica para la obtención de fármacos co...

Fenóis derivados da lignina, carboidratos e aminoaçúcares em serapilheira e solos cultivados com eucalipto e pastagem

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Rodinei Facco Pegoraro

2011-04-01

Full Text Available O cultivo de espécies florestais como o eucalipto em solos ocupados por pastagens pode levar a alterações no processo de decomposição de resíduos vegetais e na formação da matéria orgânica do solo (MOS, principalmente por alterar a contribuição de diferentes compostos orgânicos e modificar a atividade e a diversidade microbiana. Neste sentido, o presente estudo teve o objetivo de avaliar alterações causadas pelo cultivo do eucalipto em compostos orgânicos, tais como: fenóis derivados de lignina, carboidratos e aminoaçúcares, visando identificar o estádio de decomposição e a contribuição de compostos de origem microbiana para a MOS em solos do litoral Norte do Espírito Santo em comparação àqueles de pastagem. Os resultados indicaram menor aporte de carboidratos e teor de lignina similar na serapilheira de eucalipto em comparação àqueles da pastagem. Os fenóis derivados de lignina, que se caracterizaram pela presença de compostos do grupo cinamil (ácidos ferúlico e p-coumárico em maior teor, refletiram em maior acúmulo destes compostos e carboidratos totais no solo de pastagem, embora os teores totais de lignina, COT, NT e aminoaçúcares tenham sido semelhantes entre os cultivos. Nos solos cultivados com eucalipto obteve-se maior contribuição de componentes de origem vegetal (menor relação H/P para a MOS que aqueles de origem microbiana em comparação aos solos sob pastagem. O teor de determinados aminoaçúcares, como a glucosamina, nos solos indicou que os fungos são mais abundantes que bactérias e actinomicetos, especialmente no solo de pastagem.

Cuantificación espectrofotométrica de compuestos fenólicos y actividad antioxidante en distintos berries nativos del Cono Sur de América

OpenAIRE

Lillo, A; Carvajal-Caiconte, F; Nuñez, D; Balboa, N; Alvear Zamora, M

2016-01-01

El objetivo de este trabajo consistió en determinar distintos tipos de fenoles en algunos berries nativos del Cono Sur y el arándano por métodos espectrofotométricos y su relación con la actividad antioxidante. Para esto se realizaron los análisis de fenoles totales, flavonas y flavonoles totales, proantocianidinas totales, antocianinas totales, ácidos fenólicos totales, taninos totales y la actividad antioxidante por los métodos de DPPH+ y ABTS•+, en extractos de Ugni molinae, Aristotelia ch...

El fenómeno youtuber y su expansión transmedia. Análisis del empoderamiento juvenil en redes sociales

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Tatiana HIDALGO-MARÍ

2017-12-01

Full Text Available Este trabajo se acerca al fenómeno del empoderamiento juvenil en las redes sociales, en concreto YouTube, como sinónimo del triunfo juvenil conseguido a través de las social networks, fuentes generadoras de marca personal e ingresos económicos. Para ello estudia el alcance de los canales de los diez youtubers españoles más relevantes según Social Blade, así como la expansión y alcance transmedia de su personal branding. El análisis descriptivo de sus canales y los últimos vídeos publicados permiten detectar el uso prioritario de los vínculos a otras redes sociales como Facebook, Twitter e Instagram, así como los contenidos lúdicos de entretenimiento.

Estudos de biotransformação de pesticidas organofosforados e biometilação de compostos fenólicos por fungos de ambiente marinho

OpenAIRE

Paulo Roberto Serrão Soares

2016-01-01

Os pesticidas organofosforados são amplamente utilizados na agricultura, pois são muito eficazes no controle de pragas, promovendo um aumento na produtividade dos alimentos. Contudo, sua utilização indiscriminada provoca graves problemas ambientais e para a saúde humana, uma vez que são tóxicos também para as espécies que não são alvos e acumulam grandes quantidades de metabólitos tóxicos, como por exemplo, fenois. Os compostos fenólicos enquadram-se nos resíduos resultantes da degradação de ...

Bathypelagic particle flux signatures from a suboxic eddy in the oligotrophic tropical North Atlantic: production, sedimentation and preservation

Science.gov (United States)

Fischer, G.; Karstensen, J.; Romero, O.; Baumann, K.-H.; Donner, B.; Hefter, J.; Mollenhauer, G.; Iversen, M.; Fiedler, B.; Monteiro, I.; Körtzinger, A.

2015-11-01

Particle fluxes at the Cape Verde Ocean Observatory (CVOO) in the eastern tropical North Atlantic for the period December 2009 until May 2011 are discussed based on bathypelagic sediment trap time series data collected at 1290 and 3439 m water depth. The typically oligotrophic particle flux pattern with weak seasonality is modified by the appearance of a highly productive and low oxygen anticyclonic modewater eddy (ACME) in winter 2010. The eddy passage was accompanied by unusually high mass fluxes, lasting from December 2009 to May 2010. Distinct biogenic silica (BSi) and organic carbon flux peaks were observed in February-March 2010 when the eddy approached CVOO. The flux of the lithogenic component, mostly mineral dust, was well correlated to that of organic carbon in particular in the deep trap samples, suggesting a close coupling. The lithogenic ballasting obviously resulted in high particle settling rates and, thus, a fast transfer of epi-/mesopelagic signatures to the bathypelagic traps. Molar C : N ratios of organic matter during the ACME passage were around 18 and 25 for the upper and lower trap samples, respectively. This suggests that some production under nutrient (nitrate) limitation in the upper few tens of meters above the zone of suboxia might have occurred in the beginning of 2010. The δ15N record showed a decrease from January to March 2010 while the organic carbon and N fluxes increased. The causes of enhanced sedimentation from the eddy in February/March 2010 remain elusive but nutrient depletion and/or a high availability of dust as ballast mineral for organic-rich aggregates might have contributed to the elevated fluxes during the eddy passage. Remineralization of sinking organic-rich particles could have contributed to the formation of a suboxic zone at shallow depth. Although the eddy has been formed in the African coastal area in summer 2009, no indication of coastal flux signatures were found in the sediment traps, suggesting an

O centróide da piscina de água quente do pacífico como um indicador dos fenômenos El Niño e La Niña

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Fabio Vieira Machado

2014-09-01

Full Text Available Os fenômenos oceanográficos El Niño e La Niña foram analisados através do monitoramento da série temporal da componente zonal do centroide da piscina de água quente do Pacífico (PAQ que descreve movimentos leste-oeste ao longo da faixa intertropical deste oceano. Utilizou-se uma série de dados de temperatura da superfície do Oceano Pacífico para classificar a PAQ e estimar o seu centroide entre 1981 e 2003. Todos os episódios de El Niño (1982-83; 1986-87; 1990-95; e 1997-98 e La Niña (1984-85; 1988-89; 1998-2000 existentes no período analisado puderam ser observados na série temporal de dados da componente zonal da PAQ (CZPAQ. Os episódios mais intensos de El Niño foram classificados pela ordenação decrescente dos maiores deslocamentos para leste (ranking. A série de dados da CZPAQ se apresentou em fase com o índice de Oscilação Sul e com a anomalia da temperatura superficial do oceano (TSO. As flutuações associadas ao movimento zonal do centroide da PAQ foram observadas no espectro de energia onde ficaram ressaltadas as flutuações interanuais associadas aos fenômenos El Niño e La Niña. Foram observados deslocamentos mais curtos para oeste durante os anos de La Niña, quando comparados aos deslocamentos para leste durante os eventos de El Niño. A migração zonal da PAQ, representada aqui pelo centroide, apresentou-se, portanto, como um indicador dos fenômenos El Niño e La Niña. A principal vantagem dessa técnica é a dependência de um único parâmetro arbitrário, que é o limiar da TSO para delinear a PAQ.

“Spain is different”: El turismo como fenómeno de masas en los años sesenta en España

OpenAIRE

Egea Moya, Natalia

2015-01-01

El presente trabajo analizar el fenómeno que supuso el turismo de masas, o turismo de sol y playa en España en la década de los sesenta. Para ello, se estudia el contexto económico y político de la época, la actuación de las empresas privadas, las características de ese modelo turístico y la imagen del país que se vende al exterior mediante la promoción y el cine. Además, se presenta el caso concreto de La Manga del Mar Menor (Murcia), como núcleo receptor de ese tipo de turismo en dicha époc...

The first decade of oligotrophication in Lake Constance : I. The response of phytoplankton biomass and cell size.

Science.gov (United States)

Gaedke, Ursula; Schweizer, Anette

1993-03-01

Phytoplankton biomass and species composition were measured with a relatively high temporal resolution (once or twice a week during the growing season) from 1979 to 1989 in Lake Constance/Überlingersee. Over this period soluble reactive phosphorus (SRP) concentrations during winter mixing were reduced by ca. 50% from 104 to 47 μg 1 -1 , which caused a prolongation and amplification of the epilimnetic P depletion during the growth period. Seasonal dynamics of phytoplankton reacted to the decrease of SRP in the following ways: (1) Algal biomass decreased at least proportionally to the winter SRP concentrations in summer, but not in spring and autumn when biomass fluctuated irregularly. (2) The peak of biomass concentration changed from summer to spring. (3) The earlier onset of epilimnetic P depletion during the season in recent years promoted a stronger growth of some pennate diatoms in spring. It caused an amplification of the silicon depletion in summer, which may cause still greater reduction of diatoms and total algal biomass in summer. (4) Reduction of algal biomass during the clear-water phase proper became shorter and less pronounced. (5) The temporal variability of algal biomass decreased in summer and autumn but not in spring. (6) Average cell sizes remained unchanged in summer and autumn but increased in spring during the beginning of oligotrophication. These results are largely in agreement with other studies on lake restoration and expectations derived from the PEG (Plankton Ecology Group) model (Sommer et al. 1986). They show that a 50% reduction of SRP concentrations during homothermy may have pronounced effects on seasonal dynamics of algal biomass in a large and deep lake. The algal response to the external change of SRP concentrations can be described by the Le Chatelier principle, implying that the internal structure of the system (e.g. species composition) changes in order to minimize the effect of the external pressure (e.g. reduction of total

Una propuesta esquemática para el análisis de la autoconstrucción en Latinoamérica como fenómeno masivo y plural

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Salas, Julian

1988-12-01

Full Text Available The importance of the building phenomenon, known as self-build is particularly marked in Latin America: by virtue of its quantitative volume, and of the variety of the forms and types in which it can appear The author proposes a series of possible classifications of self-build from the following points of view: as a process; as a product; technological context and socio-political context. The work sets out eleven typical cases of self-build processes in very different parts of Latin America, and analyses them according to previously established criteria. The outcome, shown as a graph, clearly shows the different variations which can exist in the wide context of a single phenomenon: self-build.

La importancia del fenómeno constructivo, conocido como autoconstrucción, es especialmente importante en Latinoamérica: por su volumen cuantitativo y por sus muy diversas modalidades y manifestaciones. Los autores proponen una serie de clasificaciones posibles de la autoconstrucción desde los siguientes puntos de vista: como proceso, como producto; marco tecnológico y marco sociopolítico. En el trabajo se enuncian once casos-tipo de procesos de autoconstrucción, en muy diversos puntos de Latinoamérica, y se analizan según los criterios previamente establecidos. El resultado, representado en forma gráfica, muestra con nitidez las diferentes matizaciones que pueden establecerse en el contexto amplio del mismo fenómeno: la autoconstrucción.

A formação do enfermeiro e o fenômeno das drogas no Sul do Brasil: atitudes e crenças dos estudantes de enfermagem sobre o cuidado La formación del enfermero y el fenómeno de las drogas en el Sul de Brasil: actitudes y creencias de estudiantes de enfermería sobre la atención Nursing formation and the drugs phenomenon in the South of Brazil: nursing students' attitudes and beliefs on care

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Telma Elisa Carraro

2005-10-01

Full Text Available Pesquisa descritiva sobre a formação do enfermeiro e sua relação com o fenômeno das drogas, realizada com alunos do último período de Graduação em Enfermagem de cinco Instituições Federais de Ensino Superior do sul do Brasil. Este artigo apresenta e discute atitudes e crenças dos estudantes de enfermagem sobre o cuidado frente ao fenômeno das drogas. A coleta dos dados aconteceu de outubro/2003 a fevereiro/2004, a amostra, intencional, foi composta por 105 alunos que responderam a um instrumento contendo uma escala sobre atitudes e crenças dos enfermeiros em relação à alcoolismo e drogas. O estudo apontou que os alunos compreendem que o conhecimento sobre o fenômeno das drogas é fundamental para o exercício da profissão e incorporam o cuidado às pessoas envolvidas com substâncias psicoativas ao papel do enfermeiro. Evidenciou também desarticulação entre a teoria e a prática, conteúdos centrados nos modelos médico e moral, e dificuldades na comunicação interpessoal.Investigación de modalidad descriptiva que trata sobre la formación del enfermero y surelación con el fenómeno de las drogas, realizado con los alumnos del último ciclo de Graduación en Enfermería de cinco Instituciones Federales de Educación Superior en el Sur del Brasil. El presente artículo presenta y discute las actitudes y las creencias de los estudiantes de enfermería sobre el cuidado frente al fenómeno de las drogas. La colecta de los datos aconteció durante el período de octubre del 2003 a febrero del 2004, la muestra intencional, estuvo compuesta por 105 alumnos, los cuales respondieron a un instrumento que contenía una escala sobre las actitudes y las creencias de los enfermeros con relación al alcoholismo y a las drogas. El estudio apuntó la comprensión de los alumnoscon respecto al conocimiento del fenómeno de las drogas como fundamental e imprescindible para el ejercicio profesional, asi también incorporan el cuidado a las

Acciones gubernamentales frente a los desastres provocados por fenómenos hidrometeorológicos en México

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Gabriel Angelotti Pasteur

2015-02-01

Full Text Available Las acciones realizadas tras los desastres constituyen una oportunidad para el cambio social, en específico, para construir sociedades resilientes. Sin embargo, cuando en los procesos de reconstrucción se persiguen intereses exógenos (económicos, sociales o políticos y, preferentemente, ajenos a las necesidades de la sociedad afectada, se incrementan las condiciones de riesgo y la vulnerabilidad ante futuras amenazas. En el presente trabajo se analiza lo ocurrido en Yucatán (México cuando, tras el paso del huracán Isidoro (2002, se implementó un programa de reconstrucción con el fin de suplir aquellas viviendas que habían sido dañadas y destruidas por ese fenómeno hidrometeorológico. Mediante el mismo se esperaba dotar a las familias damnificadas de una vivienda digna, resistente, moderna y, de este modo, contribuir a forjar una sociedad más segura. Sin embargo, los resultados alcanzados ponen en duda esta meta del gobierno.

Suicidio en Bogotá: un fenómeno que aumenta en poblaciones jóvenes.

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Ricardo Sánchez

2002-12-01

Full Text Available Para analizar los patrones bimodales de la edad en víctimas de suicidio de Bogotá en tres puntos de corte, 1990, 1995 y 2000, se llevó a cabo un estudio observacional analítico con base en los expedientes del Instituto Nacional de Medicina Legal analizados mediante aplicación de modelos estadísticos de distribuciones de mezcla finita. Se analizaron 222 suicidios en 1990, 272 en 1995 y 330 en el 2000. Se comprobó la presencia de un patrón bimodal en cada uno de los años analizados. Las medias de cada uno de los componentes responsables de las dos modas se hicieron progresivamente menores con el transcurso del tiempo. En Bogotá se dio una distribución bimodal en la edad de los suicidas a lo largo del período analizado. La tendencia de las medias sugiere que, con el transcurso del tiempo, los suicidios en Bogotá tienden a ocurrir en personas más jóvenes. Este fenómeno debe ser objeto de investigación adicional y de aplicación de estrategias específicas en salud mental dirigidas a estos grupos en riesgo.

O Fenótipo Ampliado do Autismo em genitores de crianças com Transtorno do Espectro Autista - TEA

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Renata Giuliani Endres

Full Text Available RESUMOPesquisadores têm identificado expressões mais leves de traços do Transtorno do Espectro do Autismo - TEA em pais e irmãos destes indivíduos, que são definidas como Fenótipo Ampliado do Autismo (FAA. Este estudo investigou o perfil de personalidade de 20 genitores de crianças com o diagnóstico de TEA, utilizando a Bateria Fatorial de Personalidade e o Broad Autism Phenotype Questionnaire. Os resultados apontam para a presença de alguns traços de personalidade (ex: tendência à rigidez e ao retraimento social que podem, em alguma medida, corresponder às áreas de comprometimento presentes no TEA. Estes achados refletem um campo promissor de estudos no Brasil, sobretudo porque se utilizou um instrumento brasileiro, ainda não empregado em investigações na área do autismo.

Evaluation of the 46Ti(n,2n)45Ti and 54Fe(n,2n)53m+gFe reaction cross sections for neutron dosimetry in fusion facilities

International Nuclear Information System (INIS)

Badikov, S.A.; Ignatyuk, A.V.; Zolotarev, K.I.; Pashchenko, A.B.

1993-11-01

The reaction cross-sections of 46 Ti(n,2n) 45 Ti and 54 Fe(n,2n) 53m+g Fe, which are important for fusion reactor neutron dosimetry, were evaluated using a generalized least squares method. The experimental cross-section data of all measurements performed up to January 1993, were critically reviewed. The evaluated cross-section data are presented in analytical form and in ENDF-6 format, including covariance data. (author)

Migraciones Visuales: análisis del fenómeno migratorio a través del videoarte

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Célia Riboulet

Full Text Available Este ensayo explora los modos en los que la migración se desplaza (en el espacio y en el tiempo a través de las problemáticas relativas a la habitación (la casa, lengua, memoria, identidad y arquitectura. También analiza las diferentes modificaciones que generan los desplazamientos en diferentes tiempos y territorios. Porque "el arte contemporáneo se encuentra en la frontera que separa la información de la ficción, frontera entre el documental y la puesta en abismo de nuestra sociedad" (Renard, 2007, p.17 y está elegido (y más específicamente el videoarte como soporte posible para el análisis del tema estudiado: migraciones. Las nociones de fronteras, territorios, exilios, cuestionamientos identitarios y espaciales están en medio de los procesos artísticos de varios artistas "migrantes" o "no migrantes". Algunos rechazan la definición de artista migrante, no obstante sus historias personales nutren sus creaciones; otros "no migrantes" han tratado el tema como un fenómeno de relevante importancia política, social, histórica, etc.

El fenómeno migratorio en Galicia: del obrero emigrante al ciudadano acogedor… ¿lecciones aprendidas?

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Xosé Manuel Malheiro Gutiérrez

2013-02-01

Full Text Available La emigración a América ha sido un fenómeno de gran repercusión en la historia reciente de Galicia. Parte de nuestro presente se desarrolla alrededor de este hecho, incidiendo en la economía, demografía, sociedad, cultura o educación… Galicia, tradicional exportadora de mano de obra (inicialmente a América; más tarde a Europa sigue enviando mano de obra joven y preparada hacia otras regiones. Sin embargo, en algunas zonas de Galicia, el incremento de la inmigración a la que hay que añadir la que conforman los retornados, empieza a tener presencia en la sociedad.El presente trabajo analiza los patrones socioculturales que tienden a repetirse entre la partida de nuestros abuelos a América y la llegada de trabajadores inmigrantes que ahora acogemos provenientes de Centroeuropa, Magreb, África subsahariana o Latinoamérica; elabora una serie de conclusiones…, y plantea un interrogante: ¿Hemos aprendido, antaño como inmigrantes, alguna lección que nos ayude a entender y aceptar a los que ahora recibimos?

Elementos del pensamiento sistémico en la elaboración de explicaciones sobre el fenómeno de la caída de los cuerpos

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Clara Inés Chaparro Susa

2012-04-01

Full Text Available Se busca consolidar una opción pedagógica y didáctica para la enseñanza de la física mediante la elaboración de explicación de los fenómenos naturales y el desarrollo del pensamiento sistémico de los estudiantes. En este trabajo se aportan elementos en la explicación de la caída de los cuerpos desde la perspectiva de los sistemas dinámicos en dos niveles de educación: básica y universitaria.

Physicochemical properties, phenolic acids and volatile compounds of oil extracted from dry alhydwan (Boerhavia elegana Choisy seeds

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Al-Farga, A.

2015-09-01

Full Text Available In this study, the chemical composition, physicochemical properties, phenolic acids and volatile compounds of alhydwan (Boerhavia elegana Choisy seed oil were evaluated. The crude oil content was 11.49%, ash 6.88%, moisture 6.12%, protein content 14.60%, total carbohydrate 24.77% and fiber 36.13%. The oil contain a high quantity of unsaturated fatty acids (74.63 mg·100 g−1 with oleic (C18:1 (57.77%, palmitic (C16:0 (18.65% and linoleic (C18:2 (12.88% acids as the most abundant. The relative density was 0.88 and the iodine value 105.59. The color analysis showed a value of 28.33 Y+1.43 R. The oil also had a high relative oxidative stability. The tocol composition showed that α-tocotrienol, γ-tocopherol and γ-tocotrienol were in a higher concentration than the rest. Seven phenolic acids (caffeic, vanillic, galic, p-coumaric, ascorbic, cinnamic and ferulic were detected, with ascorbic acid as the predominant one (5.44 mg·100 g−1. In relation to the volatile composition, 48 compounds were found with Z-10-Pentadecen-1-ol (56.73%; Hexadecenoic acid, Z-11- (18.52%; 9,12-Octadecadienoic acid (Z,Z- (3.93% and 9,12-Octadecadienoic acid (Z,Z-, 2-hydroxy-1-(hydroxymethyl ethyl ester (3.04% as the most abundant. These findings demonstrated the potential of alhydwan seeds to be used as a good source of quality edible oil.En este estudio se ha determinado la composición química, las propiedades físico-químicas, ácidos fenólicos y compuestos volátiles de aceites de semillas de alhydwan (Boerhavia elegana Choisy. Las semillas contenían un 11.49% de aceite, 6.88% de cenizas, 6,12% de humedad, 14.60% de proteínas, 24.77% de carbohidratos totales y 36.13% de fibra. El aceite contiene 74,63 mg·100 g−1 de ácidos grasos insaturados, con oleico (C18: 1 (57,77%, palmítico (C16: 0 (18,65% y linoleico (C18: 2 (12,88% como los más abundantes. La densidad relativa fue de 0,88 y el índice de yodo de 105,59. El análisis del color mostró un valor de

La actividad carbonífera y su incidencia en las necesidades básicas humanas. Una aproximación al fenómeno de violencia estructural en el municipio de Albania, Guajira.

OpenAIRE

Cardozo Sánchez, Diego Fernando

2015-01-01

La presente investigación tiene como objetivo, determinar la manera a partir de la cual, las posibles consecuencias de la actividad carbonífera en el complejo minero de El Cerrejón, sobre las necesidades básicas humanas de la población del municipio de Albania Guajira, pueden ser consideradas como un fenómeno de violencia estructural.

Contenido fenólico y capacidad antioxidante de fresa mínimamente procesada sometida a tratamientos de conservación por pulsos de luz de alta intensidad

OpenAIRE

Chordi Barrufet, Silvia

2013-01-01

La utilización de tratamientos de luz pulsada es efectiva para la descontaminación de productos vegetales al tener poder antimicrobiano. El tratamiento con pulsos de luz en fresa mínimamente procesada provocó una ligera disminución del contenido de compuestos fenólicos totales, pero no afectó a la capacidad antioxidante ni al contenido de antocianinas totales. El tiempo de almacenamiento y la presencia de antioxidantes produjeron cambios en la composición de los compuestos bioactivos presente...

Aproximaciones teóricas para el estudio de procesos de racialización y sexualización en los fenómenos migratorios de Chile

OpenAIRE

Tijoux, María Emilia; Palominos Mandiola, Simón

2016-01-01

El objetivo del presente documento es proveer una discusión conceptual que permita reconstruir las nociones de racialización y sexualización, aplicándolas en el estudio de fenómenos migratorios que actualmente tienen lugar en la sociedad chilena, a partir de discusiones teóricas que recogen aportes de las ciencias sociales y las humanidades, la definición de racialización y sexualización enfatiza la constitución e identificación de relaciones de poder que construyen categorías de raza y de gé...

Avaliação de compostos fenólicos em geléia de uva produzida com a variedade IAC-138-22 (máximo)

OpenAIRE

Luciula Lemos Lima Morelli

2011-01-01

Resumo: O presente trabalho buscou avaliar a presença de compostos fenólicos antioxidantes em geleia de uva produzida com a variedade Máximo (IAC-138-22), por meio de (1) métodos colorimétricos e (2) cromatografia liquida de alta eficiência. Foram produzidas 3 formulações de geleia com a nova variedade e 3 outras com a mistura entre as variedades Niágara Rosada e Isabel, para efeito comparativo. As formulações diferiam em relação à quantidade de casca de uva incorporada à formulação, sendo a ...

On the molecular basis of the activity of the antimalarial drug chloroquine: EXAFS-assisted DFT evidence of a direct Fe-N bond with free heme in solution

Science.gov (United States)

Macetti, Giovanni; Rizzato, Silvia; Beghi, Fabio; Silvestrini, Lucia; Lo Presti, Leonardo

2016-02-01

4-aminoquinoline antiplasmodials interfere with the biocrystallization of the malaria pigment, a key step of the malaria parasite metabolism. It is commonly believed that these drugs set stacking π···π interactions with the Fe-protoporphyrin scaffold of the free heme, even though the details of the heme:drug recognition process remain elusive. In this work, the local coordination of Fe(III) ions in acidic solutions of hematin at room temperature was investigated by extended x-ray absorption fine structure (EXAFS) spectroscopy in the 4.0-5.5 pH range, both in the presence and in the absence of the antimalarial drug chloroquine. EXAFS results were complemented by DFT simulations in polarizable continuum media to model solvent effects. We found evidence that a complex where the drug quinoline nitrogen is coordinated with the iron center might coexist with formerly proposed adduct geometries, based on stacking interactions. Charge-assisted hydrogen bonds among lateral chains of the two molecules play a crucial role in stabilizing this complex, whose formation is favored by the presence of lipid micelles. The direct Fe-N bond could reversibly block the axial position in the Fe 1st coordination shell in free heme, acting as an inhibitor for the crystallization of the malaria pigment without permanently hampering the catalytic activity of the redox center. These findings are discussed in the light of possible implications on the engineering of drugs able to thwart the adaptability of the malaria parasite against classical aminoquinoline-based therapies.

Inflammatory Effects of the Plant Protection Product Stifenia (FEN560 on Vertebrates

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Olivier Lamotte

2017-04-01

Full Text Available Plant defense stimulators (PDSs rely on the activation of plant innate immunity in order to protect crops against various pests. These molecules are thought to be a safer alternative to classical plant protection products. Given that innate immune systems share common features in plants and vertebrates, PDS can potentially cross-react with innate immunity of non-target organisms. To test this hypothesis, we studied effects of the commercial PDS Stifenia (FEN560, which is composed of crushed fenugreek seeds. We tested various concentrations of Stifenia (0.03–1 mg mL−1 on human peripheral blood mononuclear cells and checked, 20 h later, cell metabolic activity (MA using XTT assay, cell death by flow cytometry analysis, and IL-1β inflammatory cytokine released in the culture medium using ELISA. Stifenia induced a general decrease of the cell MA, which was concomitant with a dose-dependent release of IL-1β. Our results highlight the activation of human immune cells. The inflammatory effect of Stifenia was partially inhibited by pan-caspase inhibitor. Accordingly, Stifenia induced the release of p20 caspase-1 fragment into the culture medium suggesting the involvement of the NLRP3 inflammasome. Furthermore, we observed that Stifenia can induce cell death. We also tested the effect of Stifenia on Zebrafish larvae. After 24 h of exposure, Stifenia induced a dose-dependent IL-1β and TNFα gene expression. The human-cell-based approach developed in this work revealed a high sensitivity concerning inflammatory properties of a plant protection product. These tests could be routinely used to screen the potential adverse effects of this type of compounds. Finally, our results suggest a potential danger of using extensively certain PDS for crop protection.

Fen (n=1–6) clusters chemisorbed on vacancy defects in graphene: Stability, spin-dipole moment, and magnetic anisotropy

KAUST Repository

Haldar, Soumyajyoti

2014-05-09

In this work, we have studied the chemical and magnetic interactions of Fen (n=1–6) clusters with vacancy defects (monovacancy to correlated vacancies with six missing C atoms) in a graphene sheet by ab initio density functional calculations combined with Hubbard U corrections for correlated Fe-d electrons. It is found that the vacancy formation energies are lowered in the presence of Fe, indicating an easier destruction of the graphene sheet. Due to strong chemical interactions between Fe clusters and vacancies, a complex distribution of magnetic moments appear on the distorted Fe clusters which results in reduced averaged magnetic moments compared to the free clusters. In addition to that, we have calculated spin-dipole moments and magnetic anisotropy energies. The calculated spin-dipole moments arising from anisotropic spin density distributions vary between positive and negative values, yielding increased or decreased effective moments. Depending on the cluster geometry, the easy axis of magnetization of the Fe clusters shows in-plane or out-of-plane behavior.

Determinación de la capacidad antioxidante y compuestos fenólicos de cereales andinos: quinua (Chenopodium quinoa), kañiwa (Chenopodium pallidicaule) y kiwicha (Amaranthus caudatus)

OpenAIRE

Repo de Carrasco, Ritva; Encina Zelada, Christian Rene

2008-01-01

Se realizó la extracción de compuestos hidrofílicos y lipofílicos de cereales andinos, siendo el de mayor contenido en ambos casos la muestra de kañiwa (Chenopodium pallidicaule variedad cupi), siguiendo la de quinua (Chenopodium quinoa ecotipo marrón) y finalmente la kiwicha (Amaranthus caudatus ecotipo negra). Se realizó la determinación del contenido de compuestos fenólicos en quince variedades de quinua, siendo la de mayor contenido la variedad PIQ031046 con 139,94 mg ácido gálico/100 g; ...

Ozone effects on Sphagnum mosses, carbon dioxide exchange and methane emission in boreal peatland microcosms

International Nuclear Information System (INIS)

Niemi, Riikka; Holopainen, Toini; Martikainen, Pertti J.; Silvola, Jouko

2002-01-01

Microcosms of a boreal peatland originating from an oligotrophic fen in Eastern Finland were fumigated under four ozone concentrations (0, 50, 100 and 150 ppb O 3 ) in laboratory growth chambers during two separate experiments (autumn and summer) for 4 and 6 weeks, respectively. Ozone effects on Sphagnum mosses and the fluxes of carbon dioxide and methane were evaluated. In both experiments, the three Sphagnum species studied showed only a few significant responses to ozone. In the autumn experiment, membrane permeability of S. angustifolium, measured as conductivity and magnesium leakage, was significantly higher under ozone fumigation (P=0.005 and 2 exchange during the 6-week-long summer experiment, but dark ecosystem respiration was transiently increased by ozone concentration of 100 ppb after 14 days of exposure (P<0.05). Fumigation with 100 ppb of ozone, however, more than doubled (P<0.05) methane emission from the peatland monoliths. Our results suggest that increasing tropospheric ozone concentration may cause substantial changes in the carbon gas cycling of boreal peatlands, even though these changes are not closely associated with the changes in Sphagnum vegetation

Characterizing Early Succession Following Wildfires at Different Severities in Boreal Bog and Fen Peatlands

Science.gov (United States)

Ernst, E. J.; Bourgeau-Chavez, L. L.; Kane, E. S.; Wagenbrenner, J. W.; Endres, S.

2016-12-01

The Arctic-boreal region is experiencing changes in climate, trending toward warmer summers, resulting in a greater occurrence of wildfires with longer burning periods and higher intensities. Drought-like conditions have dried surface fuels, leading to a higher probability of ignition, even in lowland peatlands. Previous work has been done to characterize post-fire succession rates in Arctic-boreal upland sites, but much less is known of fire effects and early successional dynamics in lowlands. Wildland fires are the number one disturbance in Canada's Northwest Territories (NWT), which characteristically burn at high intensities with large flame fronts, and result in some of the biggest wildfires in the world. Areas surrounding the Great Slave Lake, NWT—including parts of the Taiga Plains, Taiga Shield, and Boreal Plains ecozones—experienced exceptional wildfire activity in 2014 and 2015. We characterized burn severity of the bog and fen peat surface and canopy layers at several burned sites. To determine if the severe ground or crown wildfires were stand-replacing events, we characterized post-fire vegetation in peatlands in 2015 and 2016 based on seedling regeneration. We stratified sites according to estimated water residence times across the three ecozones and made comparisons between data collected at the same sites across years. This work adds much needed context for post-fire succession in boreal peatland ecosystems, as the susceptibility of these systems to burning will continue to increase with a warming climate.

Microscopie par rayons X dans la fenêtre de l'eau : faisabilité et intérêt pour la biologie d'un instrument de laboratoire

Science.gov (United States)

Adam, J. F.; Moy, J. P.

2005-06-01

La biologie étudie des structures ou des phénomènes sub-cellulaires. Pour cela la microscopie est la technique d'observation privilégiée. La résolution spatiale de la microscopie optique s'avère bien souvent insuffisante pour de telles observations. Les techniques plus résolvantes, comme la microscopie électronique par transmission sont souvent destructrices et d'une complexité peu adaptée aux besoins des biologistes. La microscopie par rayons X dans la fenêtre de l'eau permet l'imagerie rapide de cellules dans leur milieu naturel, nécessite peu de préparation et offre des résolutions de quelques dizaines de nanomètres. De plus, il existe un bon contraste naturel entre les structures carbonées (protéines, lipides) et l'eau. Actuellement cette technique est limitée aux centres de rayonnement synchrotron, ce qui impose une planification et des déplacements incompatibles avec les besoins de la biologie. Un tel microscope fonctionnant avec uns source de laboratoire serait d'une grande utilité. Ce document présente un état de l'art de la microscopie par rayons X dans la fenêtre de l'eau. Un cahier des charges détaillé pour un appareil de laboratoire ayant les performances optiques requises par les biologistes est présenté et confronté aux microscopes X de laboratoire déjà existants. Des solutions concernant la source et les optiques sont également discutées.

Análisis mediante HPLC de la fracción fenólica del aceite de oliva virgen de la variedad Arbequina. Relación con la medida del amargor K225 y la estabilidad

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Uceda, M.

2000-10-01

Full Text Available Phenolic compounds have a high importance because of their effect on shelf life and sensorial characteristics of virgin olive oil. In this paper, the phenolic fraction of Arbequina virgin olive oils has been characterized by HPLC. Bitterness index K225, total phenols and autoxidation stability have been evaluated for olive oil samples. From the phenolic compounds separated using HPLC method, one of then (tr: 34,49 min was close correlated both with bitterness K225 and oil stability Rancimat at 98ºC. The regression coefficients, with high significance p<0,001, were r: 0.974 and r: 0.918 respectively. Phenolic compound responsible of bitterness K225 and oil stability has been found for the Arbequina virgin olive oils.Los compuestos fenólicos tienen gran importancia por su efecto sobre la estabilidad y las características sensoriales de los aceites de oliva vírgenes. En este trabajo se ha analizado mediante cromatografía líquida de alta resolución la fracción fenólica de los aceites de oliva de la variedad Arbequina. Se han determinado el amargor K225, el contenido de polifenoles totales y la estabilidad de los aceites. De los compuestos fenólicos separados por HPLC, existe uno de ellos, con un tr: 34,49 min que presenta un elevado nivel de correlación con el amargor K225 y la estabilidad Rancimat a 98ºC, presentando unos coeficientes de regresión altamente significativos, p<0.001, de r: 0.974 y r: 0.918 respectivamente. Por tanto, se ha establecido el principal responsable del amargor K225 y la estabilidad oxidativa de los aceites de la variedad Arbequina.

Emission of greenhouse gases from geographically isolated wetlands of Western Siberia

Science.gov (United States)

Golovatskaya, E.; Dyukarev, E.; Veretennikova, E.

2014-12-01

Wetlands are integral components of landscapes with specific nutrient dynamics and carbon sequestration potentials, which frequently differ, based on hydroperiod and seasonal hydropattern, as well as the constituent concentration of inputs, site-specific storages and vegetation structures. Human modifications have the potential to significantly alter controls on carbon dynamics. This study focused on determining carbon emissions (CO2 and CH4) from geographically isolated peatlands within the Ob-Tom River Interfluve area of Western Siberia affected by water diversion for municipal use by the city of Tomsk, Russia. Two oligotrophic wetlands within the study area were selected for site-specific CO2 studies, the Timiryazevskoe (16 ha) and Kirsanovskoe wetlands (29 ha), both affected by the Tomsk water intake (177 water wells 250 000 m3 water daily). Measurements of СО2 and CH4 emissions from peat surfaces were carried out bi-monthly in growing periods from 2008-2013 in two dominate vegetation zones, pine- shrub-sphagnum phytocenosis (ryam) and sedge-sphagnum fens. СО2 emissions were measured using OPTOGAS-500.4 infrared gas analyzer and dark chamber. Methane emissions were measured using static chamber method. Air samples were collected by syringes and analyzed at gas chromatograph Shimadzu-GC14B. Observations were accompanied by measurement of air temperature and humidity, surface temperature, peat temperature at various depths and the water table level. CО2 emission over the vegetative growing period had clearly pronounced seasonal dynamics with maximum values in the middle of the growing season (mid-July) and minimum values in spring and autumn. The average total flux over the studied period is 123±55 gС/m2 at sedge-sphagnum fen of Kirsanovskoe wetland and 323±66 gС/m2 at fen of Timiryazevskoe wetland. Total СО2 flux for the snow-free period at ryam sites of Timiryazevskoe and Kirsanovskoe wetlands is 238±84 and 260±47 gС/m2 accordingly. Methane

Measurement and modelling of CO2 flux from a drained fen peatland cultivated with reed canary grass and spring barley

DEFF Research Database (Denmark)

Kandel, Tanka Prasad; Elsgaard, Lars; Lærke, Poul Erik

2013-01-01

Cultivation of bioenergy crops has been suggested as a promising option for reduction of greenhouse gas (GHG) emissions from arable organic soils (Histosols). Here, we report the annual net ecosystem exchange (NEE) fluxes of CO2 as measured with a dynamic closed chamber method at a drained fen......-C m−2 in RCG and SB plots, respectively, with Rfb accounting for 32 and 22% respectively. Total estimated annual GP was −1818 ± 42 and −1329 ± 66 g CO2-C m−2 in RCG and SB plots leading to a NEE of 69 ± 36 g CO2-C m−2 yr−1 in RCG plots (i.e., a weak net source) and −41 ± 47 g CO2-C m−2 yr−1 in SB...

Análisis del Ordenamiento Territorial del municipio de San Marcos, Sucre a la luz del Fenómeno de la Niña (2009-2012)

OpenAIRE

Angulo Redondo, Katherine

2014-01-01

Este Estudio de Caso tiene como fin analizar las consecuencias del fenómeno climatológico “La Niña” sobre el Ordenamiento Territorial del municipio San Marcos en el departamento de Sucre. Se analiza y se expone el Plan Básico de Ordenamiento Territorial del municipio, con el fin de evidenciar la inclusión u omisión de la Gestión del Riesgo de Desastres y de esta manera determinar las falencias del Ordenamiento Territorial en relación con los cuerpos de agua que rodean a San Marcos y a la regi...

La heurística de el Autómaton aristotélico en fenómenos de recurrencia cíclica del sector inmobiliario y financiero

OpenAIRE

Beltrán, Diego Alberto

2017-01-01

Este artículo tiene como objetivo principal analizar las posibilidades hermenéuticas del concepto Autómaton en la explicación de ciertos tipos de fenómenos de recurrencia cíclica en la economía del sector inmobiliario y financiero. Por otra parte, se realza el valor heurístico de este concepto a través de su diálogo con la perspectiva recurrente de la historia de Louis Auguste Blanqui. La hipótesis principal señala que los ciclos de crecimiento inmobiliario de la construcción y posterior c...

Modeling plankton ecosystem functioning and nitrogen fluxes in the oligotrophic waters of the Beaufort Sea, Arctic Ocean: a focus on light-driven processes

Directory of Open Access Journals (Sweden)

V. Le Fouest

2013-07-01

Full Text Available The Arctic Ocean (AO undergoes profound changes of its physical and biotic environments due to climate change. In some areas of the Beaufort Sea, the stronger haline stratification observed in summer alters the plankton ecosystem structure, functioning and productivity, promoting oligotrophy. A one-dimension (1-D physical–biological coupled model based on the large multiparametric database of the Malina project in the Beaufort Sea was used (i to infer the plankton ecosystem functioning and related nitrogen fluxes and (ii to assess the model sensitivity to key light-driven processes involved in nutrient recycling and phytoplankton growth. The coupled model suggested that ammonium photochemically produced from photosensitive dissolved organic nitrogen (i.e., photoammonification process was a necessary nitrogen source to achieve the observed levels of microbial biomass and production. Photoammonification directly and indirectly (by stimulating the microbial food web activity contributed to 70% and 18.5% of the 0–10 m and whole water column, respectively, simulated primary production (respectively 66% and 16% for the bacterial production. The model also suggested that variable carbon to chlorophyll ratios were required to simulate the observed herbivorous versus microbial food web competition and realistic nitrogen fluxes in the Beaufort Sea oligotrophic waters. In face of accelerating Arctic warming, more attention should be paid in the future to the mechanistic processes involved in food webs and functional group competition, nutrient recycling and primary production in poorly productive waters of the AO, as they are expected to expand rapidly.