1,279 research outputs found
New simple digital self-calibration technique for pipeline ADCs using the internal thermal noise
IEEE International Symposium on Circuits and Systems, pp. 232 – 235, Seattle, EUAThis paper describes a new digital-domain selfcalibration technique for high-speed pipeline A/D converters using the internal thermal noise as input stimulus. This lowamplitude noise is amplified and recycled by the ADC itself and, due to the successive foldings, it is naturally converted into
uniform noise. This noise is then used to calculate the required calibrating-codes. As an example, the calibration of a 13-bit pipeline ADC shows that the overall linearity can be significantly improved using this technique
Seleção de linhagens de feijão-caupi para o cerrado do Amapá.
O cerrado do Amapá possui amplas características para a produção de alimentos, sendo o feijão-caupi uma grande opção. Assim, selecionar cultivares para utilização no processo mecanizado deve ser uma meta a ser seguida, sendo este o objetivo do experimento
Efficient digital self-calibration of video-rate pipeline ADCs using white gaussian noise
Proceedings of IEEE, ISCAS 2003, Vol.I, pp. 877-880A digital-domain self-calibration technique for video-rate pipeline A/D converters based on a white Gaussian noise input signal is presented. The implementation of the proposed algorithm requires simple digital circuitv. An application design example of the self-calibration of a IZb.
40 MUS CMOSpipeline ADC is shown to illustrate that the overall linearity of the ADC can be highly improved using this technique
Genótipos prostrados de feijão-caupi no Cerrado do Amapá.
O cerrado do Estado do Amapá apresenta totais condições para a produção de grãos, sendo o feijão-caupi uma das opções mais viáveis. Assim, selecionar cultivares para este ambiente deve ser uma das metas da pesquisa. No caso em estudo, o experimento objetivou avaliar linhagens de porte prostrado e semi-prostrado. Em Latossolo Amarelo, clima do tipo Ami, usou-se o delineamento experimental de blocos ao acaso e quatro repetições, adubação de 80 kg ha-1 (superfosfato triplo) e 50 kg ha-1 (cloreto de potássio). A semeadura manual ocorreu em fileiras espaçadas de 0,80 m, com área útil de 8 m2 e população de 100 mil plantas ha-1. A análise de variância mostrou diferença significativa pelo teste de Tukey (p< 0,05). O melhor desempenho produtivo de 1.216,7 kg ha-1 foi da linhagem MNC02-676F-1, que apresenta grão da subclasse mulato, seguida pela cultivar BRS-Pajeú com 1.119,0 kg ha-1, com grão da subclasse sempre verde. A linhagem BRS Juruá alcançou menor período de floração, enquanto o maior comprimento de vagem foi do genótipo MNC02-677F-2. Todas as linhagens mostraram tolerância à incidência de doenças.Disponível em: http://www.conac2012.org/resumos/pdf/133c.pdf. Acesso em: 22 jul. 2013
Application of Constructivist Grounded Theory in Nursing Research
Grounded Theory is a qualitative research method for collecting and analysing data and results into a substantive theory that is a theoretical interpretation of a delimited problem in a specific area of knowledge. In nursing, it allows to understand the process of social interaction and how the nursing team works in everyday situations. In this study we propose, based on the theoretical framework of Kathy Charmaz, to present the procedures for the application of the constructivist Grounded Theory in nursing research. Among these are the collection and analysis of concurrent data, constant comparison at all levels of analysis, initial, focused and axial coding, conducting memos, among other resources, construction of categories, evaluation and development of the theory
Effect of freshwater influx on phytoplankton in the Mandovi estuary (Goa, India) during monsoon season: Chemotaxonomy
The Mandovi estuary is a prominent water body that runs along the west coast ofIndia. It forms an estuarine network with the adjacent Zuari estuary, connected via the Cumbharjua canal. The physico-chemical conditions seen in the Mandovi estuary are influenced by two factors: the fresh water runoff during the monsoon season (June-September) and the tidal influx of coastal seawater during the summer (October to May) season. However, the effects of monsoon related changes on the phytoplankton of the Mandovi estuary are not yet fully understood. An attempt to understand the same has been made here by applying the process of daily sampling at a fixed station throughout the monsoon season. It was noticed that the onset of the monsoon is responsible for an increase in nitrate levels upto 26 μM from <1 μM during pre-monsoon and enhancement of chlorophyll a (chl a) as high as 14 μg·L-1 during the same period. The phytoplankton population was observed through both chemotaxonomy and microscopy and was found to be composed mainly of diatoms. CHEMTAX analysis further uncovers the presence of several other groups of phytoplankton, the presence of which is yet to be reported in many other tropical estuaries. It includes chrysophytes, cyanobacteria, prasinophytes, prymnesiophytes and chlorophytes. The appearance of phytoplankton groups at various stages of the monsoon was recorded, and this data is discussed in relation to environmental changes in the Mandovi estuary during the monsoon season
The mantle wedge's transient 3-D flow regime and thermal structure
Arc volcanism, volatile cycling, mineralization, and continental crust formation are likely regu-lated by the mantle wedge’s flow regime and thermal structure. Wedge flow is often assumed to follow a regular corner-flow pattern. However, studies that incorporate a hydrated rheology and thermal buoyancy predict internal small-scale-convection (SSC). Here, we systematically explore mantle-wedge dynamics in 3-
D simulations. We find that longitudinal ‘‘Richter-rolls’’ of SSC (with trench-perpendicular axes) commonly occur if wedge hydration reduces viscosities to ≤1 ∙ 10^19 Pa s, although transient transverse rolls (with trench-parallel axes) can dominate at viscosities of ~5 ∙ 10^18 - 1 ∙ 10^19 Pa s. Rolls below the arc and back arc differ. Subarc rolls have similar trench-parallel and trench-perpendicular dimensions of 100–150 km and evolve on a 1–5 Myr time-scale. Subback-arc instabilities, on the other hand, coalesce into elongated sheets, usually with a preferential trench-perpendicular alignment, display a wavelength of 150–400 km and vary on a 5–10 Myr time scale. The modulating influence of subback-arc ridges on the subarc system increases
with stronger wedge hydration, higher subduction velocity, and thicker upper plates. We find that trench-parallel averages of wedge velocities and temperature are consistent with those predicted in 2-D models. However, lithospheric thinning through SSC is somewhat enhanced in 3-D, thus expanding hydrous melting regions and shifting dehydration boundaries. Subarc Richter-rolls generate time-dependent trench-parallel temperature variations of up to ~150 K, which exceed the transient 50–100 K variations predicted in 2-D
and may contribute to arc-volcano spacing and the variable seismic velocity structures imaged beneath some arcs
Hop bioactive compounds: spontaneous vs commercial varieties
Humulus lupulus L. is a species belonging to the Cannabaceae family. Hop, as it is commonly known, is a perennial, dioecious and normally diploid (2n = 20) herbaceous plant. It is in beer production that hops have their greatest economic value at the international level. In addition, Hops contain compounds that confer sedative, diuretic anti-inflammatory and antiarthritic properties. In fact, the ethnobotanical uses of the dried flowers in pillows called "hop pads" have been used to combat insomnia while the dried and green hop inflorescences , were used in the Montesinho park area to treat urinary and digestive disorders. Since the middle Ages, it was used in infusions as a tonic; it was considered a medicinal herb.
Since there is spontaneous hops in a large part of Portugal, the collection and analysis of the aromas the α and β-acids component, and phenols of these hops may lead to the development of new and more fragrances, with interest in different areas, like beer production or cosmetics. The volatile components extracted from spontaneous hops collected in the Bragança area were analyzed and compared with those of commercial varieties.
The results obtained show a certain similarity in the monoterpene component, with β-myrcene as the major compound (more than 64% in cultivar and spontaneous samples) and notorious differences in the sesquiterpene component, evident in cases of α-humulene (12% in cultivars, 0.2% and in spontaneous) and trans-β-farnesene (not detected in cultivars, 9% in spontaneous). Also important is the richness of the sesquiterpene component in spontaneous clone, in particular in the oxygenated compounds. This profile, of both cultivar and spontaneous, shows potential for antimicrobial effects in the digestive tract, especially when these are associated with bacteria Helicobacter pylori, which will be in agreement with ethnobotanical uses of Hop.
The higher values, in the cultivars, of the α and β-acids component is expected since the Nugget cultivar is characterized by a bitter taste, due to acids, whereas the aroma cultivars, which are more required by the artisan brewers, are valued for their richness in aromas (essential oils), the richness of the spontaneous in trans-β-farnesene being determinant to the stability of the beer, or used in cosmetic products.info:eu-repo/semantics/publishedVersio
Low-voltage low-power CMOS analogue circuits for Gaussian and uniform noise generation
IEEE International Symposium on Circuits and Systems, MAY 25-28, 2003, Bangkok, Thailand. (ISI Web of Science)A CMOS analogue circuit for Gaussian noise generution as well as a novel circuitfor transforming Gaussian noise into uniform noise, hoth.designed/or operating with a supply voltoge o/ I . S K arepresented. Both circuits are optimizedfor U 0 . 3 5st~an -
dord CMOS technology using an equation-based design methodology based on generic algorithms. Electrical simulations demonstrate that high noise amplinrdes together with reasonable hondwidths
can be achieved with relatively low power dissipation. Potential applications include self-calihrution and on-chip self-testing
of video-rate analogue-to-digital converter
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