904 resultados para ransformations in production and cultivated area.
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A general survey on the transformations which occurred during 1950-1979 in the cultivated area and in the yield of five agricultural products. The only significant transformation which occurred in the grain production in southern Brazil was the expansion of the soybean crop which is related to its use as an industrial raw material and as an external trade product.-after English summary
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Polynyas in the Laptev Sea are examined with respect to recurrence and interannual wintertime ice production.We use a polynya classification method based on passive microwave satellite data to derive daily polynya area from long-term sea-ice concentrations. This provides insight into the spatial and temporal variability of open-water and thin-ice regions on the Laptev Sea Shelf. Using thermal infrared satellite data to derive an empirical thin-ice distribution within the thickness range from 0 to 20 cm, we calculate daily average surface heat loss and the resulting wintertime ice formation within the Laptev Sea polynyas between 1979 and 2008 using reanalysis data supplied by the National Centers for Environmental Prediction, USA, as atmospheric forcing. Results indicate that previous studies significantly overestimate the contribution of polynyas to the ice production in the Laptev Sea. Average wintertime ice production in polynyas amounts to approximately 55 km3 ± 27% and is mostly determined by the polynya area, wind speed and associated large-scale circulation patterns. No trend in ice production could be detected in the period from 1979/80 to 2007/08.
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The potential to sequester atmospheric carbon in agricultural and forest soils to offset greenhouse gas emissions has generated interest in measuring changes in soil carbon resulting from changes in land management. However, inherent spatial variability of soil carbon limits the precision of measurement of changes in soil carbon and hence, the ability to detect changes. We analyzed variability of soil carbon by intensively sampling sites under different land management as a step toward developing efficient soil sampling designs. Sites were tilled crop-land and a mixed deciduous forest in Tennessee, and old-growth and second-growth coniferous forest in western Washington, USA. Six soil cores within each of three microplots were taken as an initial sample and an additional six cores were taken to simulate resampling. Soil C variability was greater in Washington than in Tennessee, and greater in less disturbed than in more disturbed sites. Using this protocol, our data suggest that differences on the order of 2.0 Mg C ha(-1) could be detected by collection and analysis of cores from at least five (tilled) or two (forest) microplots in Tennessee. More spatial variability in the forested sites in Washington increased the minimum detectable difference, but these systems, consisting of low C content sandy soil with irregularly distributed pockets of organic C in buried logs, are likely to rank among the most spatially heterogeneous of systems. Our results clearly indicate that consistent intramicroplot differences at all sites will enable detection of much more modest changes if the same microplots are resampled.
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Objective The overall objective of this study was to document the nature of the chemotherapy nursing practice of rural and remote area nurses in Queensland. Design A questionnaire survey that elicited descriptive quantitative and qualitative data. Setting Forty-seven rural and remote area health facilities in Queensland involved in the administration of chemotherapy. Subjects Sixty-seven Queensland rural and remote area nurses involved in the administration of cytotoxic drugs. Main outcome measures: Characteristics of chemotherapy practice including context of practice, amount and type of chemotherapy administered, logistical problems, level of support from referral centres, policies and procedures, safety issues. Results The results indicate that the risks to nursing staff and the potential for poor patient outcomes are higher than in specialist chemotherapy facilities. This is largely due to the human and material resource constraints characteristic of rural practice. These include a lack of understanding on the part of metropolitan-based health departments and the specialist cancer centres that refer patients to rural areas of the constraints that may adversely influence patient outcomes. Conclusions It is essential that steps are taken to ensure that rural and remote area cancer patients have equitable access to safe and competent chemotherapy care delivered in their choice of context, and the results of this study provide guidance on ways that this can be achieved.
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The worldwide spread of barley cultivation required adaptation to agricultural environments far distant from those found in its centre of domestication. An important component of this adaptation is the timing of flowering, achieved predominantly in response to day length and temperature. Here, we use a collection of cultivars, landraces and wild barley accessions to investigate the origins and distribution of allelic diversity at four major flowering time loci, mutations at which have been under selection during the spread of barley cultivation into Europe. Our findings suggest that while mutant alleles at the PPD-H1 and PPD-H2 photoperiod loci occurred pre-domestication, the mutant vernalization non-responsive alleles utilized in landraces and cultivars at the VRN-H1 and VRN-H2 loci occurred post-domestication. The transition from wild to cultivated barley is associated with a doubling in the number of observed multi-locus flowering-time haplotypes, suggesting that the resulting phenotypic variation has aided adaptation to cultivation in the diverse ecogeographic locations encountered. Despite the importance of early-flowering alleles during the domestication of barley in Europe, we show that novel VRN alleles associated with early flowering in wild barley have been lost in domesticates, highlighting the potential of wild germplasm as a source of novel allelic variation for agronomic traits.
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Seit seiner Entdeckung im Jahre 1978 wurden für hyperpolarisiertes (HP) 129Xe zahlreiche Anwendungen gefunden. Aufgrund seiner hohen Verstärkung von NMR-Signalen wird es dabei typischerweise für Tracer- und Oberflächenstudien verwendet. Im gasförmigen Zustand ist es ein interessantes, klinisches Kontrastmittel, welches für dynamische Lungen MRT genutzt oder auch in Blut oder lipophilen Flüssigkeiten gelöst werden kann. Weiterhin findet HP-Xe auch in der Grundlagenphysik in He-Xe Co-Magnetometern Verwendung, mit welchen z. B. das elektrische Dipolmoment von Xe bestimmt werden soll, oder es dient zur Überprüfung auf Lorentz-Invarianzen. Alle diese Anwendungen profitieren von einem hohen Polarisationsgrad (PXe), um hohe Signalstärken und lange Lagerzeiten zu erreichen. rnIn dieser Arbeit wurden zwei mobile Xe-Polarisatoren konstruiert: einer für Experimente in der Grundlagenphysik mit einer Produktionsrate von 400 mbar·l/h mit PXe ≈ 5%. Der zweite Xe-Polarisator wurde für medizinische Anwendungen entwickelt und soll 1 bar l/h mit PXe > 20% erzeugen. Der letztere wurde noch nicht getestet. Die Arbeitsbedingungen des Xe-Polarisators für Grundlagenphysik (Strömung des Gasgemischs, Temperatur, Druck und Konzentration von Xe) wurden variiert, um einen höchstmöglichen Polarisationsgrad zu erzielen. Die maximale Polarisation von 5,6 % wurde bei Verwendung eine Gasmischung von 1% Xe bei einem Durchfluss von 200 ml/min, einer Temperatur von 150°C und einem Gesamtdruck von 4 bar erreicht. rnWeiterhin muss HP-Xe auch effizient gelagert werden, um Polarisationsverluste zu minimieren. Das ist besonders für solche Anwendungen notwendig, welche an einem entfernten Standort durchgeführt werden sollen oder auch wenn lange Spinkohärenzeiten gefordert sind, z.B. bei He-Xe Co-Magnetometern. rnHierbei bestand bisher die größte Schwierigkeit darin, die Reproduzierbarkeit der gemessenen Lagerzeiten sicherzustellen. In dieser Arbeit konnte die Spin-Gitter-Relaxationszeit (T1) von HP-129Xe in unbeschichteten, Rb-freien, sphärischen Zellen aus Aluminiumsilikatglas (GE-180) signifikant verbessert werden. Die T1–Zeit wurde in einem selbstgebauten Niederfeld-NMR-System (2 mT) sowohl für reines HP-Xe als auch für HP-Xe in Mischungen mit N2, SF6 und CO2 bestimmt. Bei diesen Experimenten wurde die maximale Relaxationszeit für reines Xe (85% 129 Xe) bei (4,6 ± 0,1) h festgestellt. Dabei lagen die typischen Wand-Relaxationszeiten bei ca. 18 h für Glaszellen mit einem Durchmesser von 10 cm. Des Weiteren wurde herausgefunden, dass CO2 eine unerwartet hohe Effizienz bei der Verkürzung der Lebensdauer der Xe-Xe Moleküle zeigte und somit zu einer deutlichen Verlängerung der gesamten T1-Zeit genutzt werden kann. rnIm Verlauf vieler Experimente wurde durch wiederholte Messungen mit der gleichen Zelle, ein "Alterungsprozess“ bei der Wandrelaxation identifiziert und untersucht. Dieser Effekt könnte leicht rückgängig gemacht werden, indem die anfängliche Reinigungsprozedur wiederholt wurde. Auf diese Weise kann eine konstante Wandrelaxation sichergestellt werden, durch die sehr reproduzierbare T1-Messungen möglich werden. rnSchließlich wurde die maximale Relaxationszeit für HP-Xe mit natürlicher Häufigkeit in Mischungen mit SF6 bestimmt. Überraschenderweise war dieser Wert um ca. 75% niedriger als der Wert für Xenon, das zu 85% mit 129Xe angereichert war. Dieser Effekt wurde durch drei unabhängige Experimente bestätigt, da er nicht von der bestehenden Theorie der Xe-Relaxation ableitbar ist. rnDie Polarisation von HP-Xe, PXe, wird normalerweise durch den Vergleich der NMR-Signale des HP-Xe mit einer thermischen polarisierten Probe (z. B. 1H2O oder Xe) bestimmt. Dabei beinhaltet der Vergleich unterschiedlicher Messungen an verschiedenen Proben (unterschiedlicher Druck, Signalintensität und Messverfahren) viele experimentelle Unsicherheiten, welche sich oft nicht leicht bestimmen lassen. Eine einfache, genaue und kostengünstige Methode zur Bestimmung von PXe durch eine direkte Messung der makroskopischen Magnetisierung in einem statischen Magnetfeld vermeidet alle diese Unsicherheiten. Dieses Verfahren kann Polarisationen von > 2 % mit einer Genauigkeit von maximal 10% fast ohne Polarisationsverlust bestimmen. Zusätzlich kann diese Methode ohne weitere Änderungen auch für Bestimmungen des Polarisationsgrades anderer HP-Gase verwendet werden.rn
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"February, 1932."
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Asparagus is the star product among non-traditional agricultural exports (NTAXs) in Peru. The export of preserved asparagus has expanded since the end of the 1980s. Although there was some stagnation in the mid-1990s, exports of fresh asparagus have expanded rapidly since the end of the 1990s. Now, the export of both preserved and fresh asparagus constitute the second most important agricultural export in Peru after coffee. Besides the change in demand on the international market, the important factor behind the shift from preserved to fresh asparagus is the change in the supply structure of asparagus. In the case of preserved asparagus, Peruvian exports expanded because of Peru’s competitiveness, which originated from favorable production factors, such as climate, soil and labor. However, because of the growing presence of Chinese products on the international market, Peru’s products lost their competitiveness. In the case of fresh asparagus, the investment of agricultural corporations in production and their innovation in integrating different economic processes from the point of production to the time of export built a successful supply structure that is suited for the export of fresh agricultural produce.
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Background In Australia, breast cancer is the most common cancer affecting Australian women. Inequalities in clinical and psychosocial outcomes have existed for some time, affecting particularly women from rural areas and from areas of disadvantage. We have a limited understanding of how individual and area-level factors are related to each other, and their associations with survival and other clinical and psychosocial outcomes. Methods/Design This study will examine associations between breast cancer recurrence, survival and psychosocial outcomes (e.g. distress, unmet supportive care needs, quality of life). The study will use an innovative multilevel approach using area-level factors simultaneously with detailed individual-level factors to assess the relative importance of remoteness, socioeconomic and demographic factors, diagnostic and treatment pathways and processes, and supportive care utilization to clinical and psychosocial outcomes. The study will use telephone and self-administered questionnaires to collect individual-level data from approximately 3, 300 women ascertained from the Queensland Cancer Registry diagnosed with invasive breast cancer residing in 478 Statistical Local Areas Queensland in 2011 and 2012. Area-level data will be sourced from the Australian Bureau of Statistics census data. Geo-coding and spatial technology will be used to calculate road travel distances from patients' residence to diagnostic and treatment centres. Data analysis will include a combination of standard empirical procedures and multilevel modelling. Discussion The study will address the critical question of: what are the individual- or area-level factors associated with inequalities in outcomes from breast cancer? The findings will provide health care providers and policy makers with targeted information to improve the management of women with breast cancer, and inform the development of strategies to improve psychosocial care for women with breast cancer.
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This paper explores the ways that young people express their agency and negotiate complex lifecourse transitions according to gender, age and inter- and intra-generational norms in sibling-headed households affected by AIDS in East Africa. Based on findings from a qualitative and participatory pilot study in Tanzania and Uganda, I examine young people's socio-spatial and temporal experiences of heading the household and caring for their siblings following their parent's/relative's death. Key dimensions of young people's caring pathways and life transitions are discussed: transitions into sibling care; the ways young people manage changing roles within the family; and the ways that young people are positioned and seek to position themselves within the community. The research reveals the relational and embodied nature of young people's life transitions over time and space. By living together independently, young people constantly reproduce and reconfigure gendered, inter- and intra-generational norms of ‘the family’, transgressing the boundaries of ‘childhood’, ‘youth’ and ‘adulthood’. Although young people take on ‘adult’ responsibilities and demonstrate their competencies in ‘managing their own lives’, this does not necessarily translate into more equal power relations with adults in the community. The research reveals the marginal ‘in-between’ place that young people occupy between local and global discourses of ‘childhood’ and ‘youth’ that construct them as ‘deviant’. Although young people adopt a range of strategies to resist marginalisation and harassment, I argue that constraints of poverty, unequal gender and generational power relations and the emotional impacts of sibling care, stigmatisation and exclusion can undermine their ability to exert agency and control over their sexual relationships, schooling, livelihood strategies and future lifecourse transitions.