975 resultados para Exportation of nutrients


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Along the N-S-transect of DSDP-Sites 5446, 397, 141, and 366, oxygen and carbon isotopes, flux rates of calcium carbonate, terrigenous matter, and biogenic opal, clay minerals and the size distribution of terrigenous partictes were determined in order to assess the ties between atmospheric and oceanic surface and deep-water circulation off northwest Africa during the late Neogene. During the last 9 m.y., both the paleoceanography in the eastern Atlantic and west African paleodimates were intimately correlated with the evolution of the polar ice sheets as reflected in the benthos d18O curves of the 4 DSDP-Sites. These records make it possible to distinguish six major time intervals which were charaterized by long-term persistent regimes of climatic stability or climatic change. Short-term, "Milankovitch"-type cycles superimpose the long-term climatic evolution and may reflect the chronostratigraphic control fluctuations of the solar insolation persisting back to pre-Pleistocene times. Relatively stable, warm climates prevailed during the late Tortonian/early Messinean, 9 to 6 m.y., and the early Pliocene, 4.5 to 3.5 m.y. ago. Based on d18O curves, the amplitudes of short-term climatic variation were generally low, and the ice sheets were smaller than during peak Holocene time. Oceanic circulation and resulting paleoproductivity in upwelling zones were insignificant. The strength of dust supplying meridional trade winds was low (3 to 5 m/s), interglacial-style zonal winds near the ITCZ were dominant, as indicated by the high abundance of kaolinite. Phases of fluvial sediment supply were common. Humidity was characteristic of the climate in northwest Africa for the major part of this time. Major episodes of climatic deterioration in the subtropics occurred in the latest Miocene/early Pliocene, between some 5.6 and 5.2 and between 4.9 and 4.6 m.y. ago, in the late Pliocene, between 3.2 and 2.4 m.y. ago, and again in the Quaternary, near 1 m.y. ago. The episodes were correlated with marked increases of the global ice volume, as revealed by drastic increases of d18O values. They suggest sea-level falls of up to 70 m below the present sea level in the latest Miocene and earliest Pliocene and of 145 m in the latest Pliocene and Quaternary. The climatic changes resulted in strongly enhanced meridional trade winds as suggested by coarser terrigenous grain-sizes, increased mass accumulation rates of eolian dust, and changes in clay-mineral composition from dominantly kaolinite to illite and chlorite. The meridional trade winds reached speeds of 8 to 10 m/s with a maximum near 15 m/s. The enhanced winds probably led t o intensified coastal upwelling as shown by the contemporaneous local increase i n the deposition of biogenic silica and the local depletion of 13C at Site 397. The most drastic environmental changes near 2.4 and 1 m.y. ago coincide with hiatuses which may indicate phases of general erosion due to strongly enhanced deep-water circulation in the northeast At1antic along the northwest African continental margin. The occasional occurrence of quartz grains coarser than 250 µm may suggest ice-rafted debris in sediments off Morocco. During these time intervals the climate in NW-Africa was dominantly arid. Nevertheless, fluvial runoff (and humidity) continued to be important during intermittent warm phases of the short-term climatic cycles. During the end and the beginning of (inter-) glacial times, fluvial supply of nutrients seems to be the dominant factor, controling phases of enhanced paleoproductivity observed off northwest Africa, whereas during phases of glacial maximum strenger fertility of (increased) coastal upwelling becomes more important. A long-term evolution of paleoenvironments during the last 40 m.y. is depicted in the sediments of Site 366 and is clearly controlled by the plate tectonic route of this Site. During Oligocene times, Site 366 lay in the center of the equatorial upwelling, as shown by the high content of biogenic silica contributing up to 100 % of the carbonate-free sediment fraction >6 µm. The influence of equatorial upwelling abruptly terminated near 15 m.y. ago, a change in the record exaggerated by a hiatus of about 2 m.y. Prior to 25 m.y., the terrigenous input at the paleolatitude of Site 366 was restricted t o eolian sediment supply from South Africa by southeasterly trade winds, as shown by dominantly illite and chlorite in the clay fraction and extremely fine-grained terrigenous matter. Near the Oligocene/Miocene boundary, Site 366 drifted across the equator into the belt of the northeasterly trade winds, which is inferred from the increased content of kaolinite and coarser grain sizes of the terrigenous sediment fraction. The clay-mineral and grain-size compositions of Site 366 do not reflect a noteworthy northward shift of the ITCZ during late Miocene and early Pliocene times, i.e. no marked global circulation asymmetry due to the possible absence of a major Northern Hemisphere glaciation (Flohn 1981). This lack of a more northerly position of the ITCZ may result from a bipolar glaciation already existing during late Miocene times, such as also suggested by the evidence of tillites on Iceland and in southern Alaska during those intervals (e.g., Denton & Amstrong 1969, Mudie & Helgason 1983).

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[EN]Previous studies have reported an association between a more pro-inflammatory diet profile and various chronic metabolic diseases. The Dietary Inflammatory Index (DII) was used to assess the inflammatory potential of nutrients and foods in the context of a dietary pattern. We prospectively examined the association between the DII and the incidence of cardiovascular disease (CVD: myocardial infarction, stroke or cardiovascular death) in the PREDIMED (Prevención con Dieta Mediterránea) study including 7216 high-risk participants.

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Malnutrition, nutritional deficiency, or undernutrition is an imbalanced nutritional status resulting from insufficient intake of nutrients to meet normal physiologic requirements. Malnutrition in childhood has both short-term consequences and long-term consequences on mental and physical health as well as the overall health development of children. Of all regions in the world, the Asia and the Pacific region has achieved the fastest rate of economic growth. There is no evidence that this rapid economic growth translates into a decline in malnutrition of children in Asian countries such as India.

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Scientific research in forest production technology area search techniques that increase production per unit area, with high economic viability and reducing environmental impacts. When dealing with forest plantations, studies are needed in the production of biomass and its nutrient content, and these are data parameters for planning the environmental implications of different intensities of forest harvesting. Given the above, this study aimed to elucidate the production and export of biomass and nutrients for two species of the genus Eucalyptus (E. grandis and E. urophylla) grown in the southwestern region of Parana. For this, it was evaluated: the stock of biomass and nutrients in eucalyptus (wood, bark, branches and leaves) at 60 months of age; the export rate of nutrients; the calorific value and economic viability. The biomass and the largest eucalyptus nutrient stocks are predominantly allocated to the stem (wood + bark). The components of biomass showed different chemical compositions, generally being higher in the leaves and bark and lower in wood and branches components. As for the calorific value, the leaves had its calorific value statistically superior than the other fractions, followed by branches, wood and bark. The organic carbon content (C.O.) is directly connected to the calorific value, and the calorific value increases as its content increase. The wood had the highest nutrient use efficiency values, something highly desirable and of great interest to forestry. The leaves showed smaller nutrient utilization efficiency values, with the exception of Ca and Mg that were smaller in the bark, indicating the importance of maintaining these components in the soil after harvest. The wood fraction presents the biomass lower cost when considering the replacement of nutrients exported by its biomass. On the other hand, the leaf fraction showed NPK higher cost of replacement.

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Fluxes of nutrients (NH sub(4) super(+), NO sub(3) super(-), PO sub(4) super(3-) and Si(OH) sub(4)) were studied on an intertidal mudflat in Marennes-Oleron Bay, France, at two different seasons and at different times of the emersion period. Fluxes through the sediment-water interface were both calculated from vertical profiles of nutrient concentration in pore-water (diffusive fluxes, JD) and measured in light and dark benthic mini-chambers (measured fluxes, J sub(0)). Results indicate that ammonia was mainly released in summer while nitrate was mainly taken up in late winter. This uptake from the overlying water was probably due to the coupling of nitrification-denitrification within the sediment. The J sub(0) /J sub(D) ratio further indicates that bioturbation likely enhanced ammonia release in summer. Concerning phosphate, the comparison of diffusive and measured fluxes suggests that PO sub(4) super(3-) could be assimilated by the biofilm in winter while it was released in summer at a high rate due to both bioturbation and desorption because of the relative summer anoxic conditions. Silica was always released by the sediment, but at a higher rate in summer. Statistically significant differences in measured fluxes were detected in dark chambers at different times of low tide, thus suggesting a short-term variability of fluxes. Microphytobenthos preferred ammonia to nitrate, but assimilated nitrate when ammonia was not available. It also turned out that benthic cells could be limited in nitrogen during low tide in late winter. In summer, ammonia was not limiting and microphytobenthic activity significantly decreased the measured flux of NH sub(4) super(+) in the middle of low tide when its photosynthetic capacity was highest.

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Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg) and arsenic (As) could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se), an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST). The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women.

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Mungbean ( Vigna radiata (L.) Wilczek) is an important source of nutrients and income for smallholder farmers in East Africa. Mungbean production in countries like Uganda largely depends on landraces, in the absence of improved varieties. In order to enhance productivity, efforts have been underway to develop and evaluate mungbean varieties that meet farmers’ needs in various parts of the country. This study was conducted at six locations in Uganda, to determine the adaptability of introduced mungbean genotypes, and identify mungbean production mega-environments in Uganda. Eleven genotypes (Filsan, Sunshine, Blackgram, Mauritius1, VC6148 (50-12), VC6173 (B-10),Yellowmungo, KPS1, VC6137(B-14),VC6372(45-60),VC6153(B-20P) and one local check were evaluated in six locations during 2013 and 2014. The locations were; National Semi Arid Resources Research Institute (NaSARRI), Abi Zonal Agricultural Research and Development Institute (AbiZARDI),Kaberamaido variety trial center, Kumi variety trial center, Nabuin Zonal Agricultural Research and Development Institute (NabuinZARDI), and Ngetta Zonal Agricultural Research and Development Institute (NgettaZARDI). G × E interactions were significant for grain yield. Through GGEBiplot analysis, three introduced genotypes (Filsan, Blackgram and Sunshine) were found to be stable and high yielding, and therefore, were recommended for release. The six test multi-locations were grouped into two candidate mega-environments for mungbean production (one comprising of AbiZARDI and Kaberamaido and the other comprising of NaSARRI, NabuinZARDI, Kumi, and NgettaZARDI). National Semi Arid Resources Research Institute (NaSARRI) was the most suitable environment in terms of both discriminative ability and representativeness and therefore can be used for selection of widely adaptable genotypes.

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The chemical factors (inorganic nitrogen, phosphate, silicic acid) that potentially or actually control primary production were determined for the Bay of Brest, France, a macrotidal ecosystem submitted to high-nitrate-loaded freshwater inputs (winter nitrate freshwater concentrations >700 mu M, Si:N molar ratio as low as 0.2, i.e. among the lowest ever published). Intensive data collection and observations were carried out from February 1993 to March 1994 to determine the variations of physical [salinity, temperature, photosynthetically active radiation (PAR), freshwater discharges] and chemical (oxygen and nutrients) parameters and their impacts on the phytoplankton cycle (fluorescence, pigments, primary production). With insufficient PAR the winter stocks of nutrients were almost nonutilized and the nitrate excess was exported to the adjacent ocean, due to rapid tidal exchange. By early April, a diatom-dominated spring bloom developed (chlorophyll a maximum = 7.7 mu g l(-1); primary production maximum = 2.34 g C m(-2) d(-1)) under high initial nutrient concentrations. Silicic acid was rapidly exhausted over the whole water column; it is inferred to be the primary limiting factor responsible for the collapse of the spring bloom by mid-May. Successive phytoplankton developments characterized the period of secondary blooms during summer and fall (successive surface chlorophyll a maxima = 3.5, 1.6, 1.8 and 1.0 mu g l(-1); primary production = 1.24, 1.18 and 0.35 g C m(-2) d(-1)). Those secondary blooms developed under lower nutrient concentrations, mostly originating from nutrient recycling. Until August, Si and P most likely limited primary production, whereas the last stage of the productive period in September seemed to be N limited instead, this being a period of total nitrate depletion in almost the whole water column. Si limitation of spring blooms has become a common feature in coastal ecosystems that receive freshwater inputs with Si:N molar ratios <1. The peculiarity of Si Limitation in the Bay of Brest is its extension through the summer period.

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After harvest, plants remain living organisms with the capacity to carry out metabolic processes. Thus, from the moment they are detached from the source of nutrients, they become entirely dependent on their own organic reserves [1]. Postharvest changes cannot be stopped, but they can be slowed within certain limits. Therefore, this study was conducted to evaluate the effects induced by storage in the profiles of sugars, organic acids and tocopherols of two leafy vegetables. Wild samples of watercress (Nasturtium officinale R. Br.) and buckler sorrel (Rumex induratus Boiss. & Reut.), from the Northeastern region of Portugal, were analyzed after harvest (control) and after storage in sterilized packages (using the passive modification mode) at 4ºC for 7 or 12 days, respectively. Analyses were performed by high-performance liquid chromatography (HPLC) using different detectors, i.e., a refraction index detector (RID) for free sugars, a photodiode array detector (PDA) for organic acids, and a fluorescence (FP) detector for tocopherols. The storage time decreased the levels of fructose, glucose and total sugars in both leafy vegetables and increased the total organic acids content. The decrease of these sugars can be related to its use by the plant to produce the required energy. Ascorbic acid was detected in buckler sorrel and decreased with storage; while the amount of malic acid increased in both species. Curiously, all the tocopherol isoforms increased in watercress, while buckler sorrel just present higher values of γ- and δ- tocopherols. In fact, the de novo synthesis of these bioactives compounds can be a plant strategy to fight against the reactive species that are produced during storage. The knowledge of the behavior of these compounds during storage that was achieved with this study [2] may contribute to the development of more effective preservation strategies for leafy vegetables.

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Several Cronobacter outbreaks have implicated contaminated drinking water. This study assessed the impact of granular activated carbon (GAC) on the microbial quality of the water produced. A simulated water filter system was installed by filling plastic columns with sterile GAC, followed by sterile water with a dilute nutrient flowing through the column at a steady rate. Carbon columns were inoculated with Cronobacter on the surface, and the effluent monitored for Cronobacter levels. During a second phase, commercial faucet filters were distributed to households for 4-month use. Used filters were backwashed with sterile peptone water, and analyzed for Cronobacter, total aerobic plate count, coliform bacteria and Enterobacteriaceae. Cronobacter colonized the simulated GAC and grew when provided minimal levels of nutrients. Backwashed used filters used in home settings yielded presumptive Escherichia coli, Pseudomonas and other waterborne bacteria. Presumptive Cronobacter strains were identified as negative through biochemical and genetic test.

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Three experiments were conducted with juveniles of the crayfish Cherax quadricarinatus to investigate the effect of intermittent feeding regimes on growth and the ability to tolerate the shortage of food. In experiment 1, stage III juveniles were assigned to one of seven intermittent feeding groups (from FS1: 1 day fed/1 day non-fed to FS7: 7 days fed/7 days non-fed) and two control groups, continuously fed (CF) and continuously starved (CS) animals; this experiment comprised a short-term intermittent feeding period until the first molt, followed by a continuous feeding period. In the experiment 2, stage III juveniles were assigned to one of three intermittent feeding groups (FS2 to FS4) and one control group (CF); it consisted of a prolonged intermittent feeding period, until the end of the experiment In the experiment 3, stage VI and VII juveniles were assigned to one of three intermittent feeding groups (FS2 to FS4) and one control (CF); it also consisted of a prolonged intermittent feeding period. The red claw crayfish juveniles were able to tolerate periods of intermittent feeding and underwent compensatory growth after continuous feed was re-established. The ability of crayfish to tolerate intermittent feeding was influenced by developmental stage and duration of the intermittent feeding period. Stage III juveniles survived, but decreased growth, when subjected to prolonged intermittent feeding. However, they showed full compensatory growth when the intermittent feeding period was short and followed by continuous feeding. on the other hand, stage VI-VII tolerated 60 days of prolonged intermittent feeding without any change in growth and survival. The hepatosomatic index (based on wet weight) values of the treatments and the control were similar, suggesting that intermittent feeding may not be considered a nutritional stress condition. The relative pleon weight (based on wet weight) values of the treatments and control were similar suggesting low use of nutrients from the muscle to increase the chance for survival. The juveniles of C quadricarinatus can tolerate relatively long periods of low food availability and this is an important adaptation for their survival in changing/unpredictable environments and an attribute favorable for the production of the species. (C) 2011 Elsevier B.V. All rights reserved.

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Introduction: Life expectancy is increasing and becoming a characteristic phenomenon of developed countries and, increasingly, of developing countries, such as Brazil. The aging process causes changes of some physiological functions such as loss of smell, taste, loss of appetite, among other things that end up changing the food intake of these individuals. Objectives: This study aimed to assess food consumption of the young and long-lived elderly in a city in southern Brazil. Methods: A cross-sectional survey conducted through home visits in Palmeira das Missões - RS, Brazil. The sociodemographic, anthropometrical and dietary data were collected through questionnaires and 24-hour recall. The adequacy of nutrients was assessed according to the Dietary Reference Intakes. Data were analyzed using SPSS 18.0 software. Results: The study included 424 older adults, 84,4% (n = 358) aged less than 80 years old and 15,6% (n = 66) older than 80. The intake of energy and protein was insufficient for both young elderly and the oldest. The consumption of vitamins and minerals has been insufficient in all seniors except for iron, which presented an excessive intake. There was a statistically significant difference between the elderly and oldest only for the consumption of lipids and vitamin B12. Conclusion: The majority of studies with elderly corroborate the results found in this article. An inadequate intake of nutrients can develop nutritional deficiencies, and consequently it can result in physiological and pathological changes which would compromise the functional capacity of the elderly. Energy consumption was insufficient and macronutrients were inadequate, both for the young elderly as for the oldest. Additionally, the consumption of vitamins and minerals was insufficient to everyone except the iron, which presented excessive intake for young and oldest elderly.

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Doutoramento em Engenharia do Ambiente - Instituto Superior de Agronomia - UL

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Understanding the factors that affect seagrass meadows encompassing their entire range of distribution is challenging yet important for their conservation. We model the environmental niche of Cymodocea nodosa using a combination of environmental variables and landscape metrics to examine factors defining its distribution and find suitable habitats for the species. The most relevant environmental variables defining the distribution of C. nodosa were sea surface temperature (SST) and salinity. We found suitable habitats at SST from 5.8 ºC to 26.4 ºC and salinity ranging from 17.5 to 39.3. Optimal values of mean winter wave height ranged between 1.2 m and 1.5 m, while waves higher than 2.5 m seemed to limit the presence of the species. The influence of nutrients and pH, despite having weight on the models, was not so clear in terms of ranges that confine the distribution of the species. Landscape metrics able to capture variation in the coastline enhanced significantly the accuracy of the models, despite the limitations caused by the scale of the study. By contrasting predictive approaches, we defined the variables affecting the distributional areas that seem unsuitable for C. nodosa as well as those suitable habitats not occupied by the species. These findings are encouraging for its use in future studies on climate-related marine range shifts and meadow restoration projects of these fragile ecosystems.

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O estudo foi efetuado durante o período de chuva (dezembro-fevereiro) em seis viveiros de produção semi-intensiva de peixes, a fim de avaliar o efeito da chuva na qualidade da água de viveiros que apresentam fluxo contínuo de água, a qual é passada de um viveiro para outro sem tratamento prévio. Foram amostrados oito pontos de coleta nas saídas dos viveiros. O viveiro P1 (próximo à nascente) apresentou as menores concentrações físicas e químicas da água e as maiores no viveiro P4 (considerado um ponto crítico recebendo material alóctone proveniente de outros viveiros e do escoamento do setor de criação de rãs). A disposição seqüencial dos viveiros estudados promoveu aumento nas concentrações dos nutrientes, clorofila-a e condutividade. As chuvas características desta época do ano aumentaram o fluxo de água nos viveiros e conseqüentemente, carreando material particulado e dissolvido de um viveiro para outro e, promovendo um aumento das variáveis limnológicas em direção do P3 ao P6. Os resultados sugerem que a chuva no período de estudo afetou positivamente a qualidade da água dos viveiros estudados, porém, como os sistemas analisados estão dispostos em distribuição seqüencial e escoamento constante da água de viveiros e tanques paralelos sem tratamento prévio, cuidados devem ser averiguados para que o aumento do fluxo de água provocado pelas chuvas não tenha efeito adverso nos viveiros estudados.