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Turbulent flow evolution and energy cascades are significantly different in two-dimensional (2-D) and three-dimensional (3-D) flows. Studies have investigated these differences in obstacle-free turbulent flows, but solid boundaries have an important impact on the cross-over from 3-D to 2-D turbulence dynamics. In this work, we investigate the span effect on the turbulence nature of flow past a circular cylinder at
. It is found that even for highly anisotropic geometries, 3-D small-scale structures detach from the walls. Additionally, the natural large-scale rotation of the Kármán vortices rapidly two-dimensionalise those structures if the span is 50 % of the diameter or less. We show this is linked to the span being shorter than the Mode B instability wavelength. The conflicting 3-D small-scale structures and 2-D Kármán vortices result in 2-D and 3-D turbulence dynamics which can coexist at certain locations of the wake depending on the domain geometric anisotropy.
A growing body of social science research has sought to conceptualize race as a multi-dimensional concept in which context, societal relations, and institutional dynamics are key components. Utilizing a specially-designed survey, we develop and use multiple measures of race (skin color, ascribed race, and discrimination experiences) to capture race as a “lived experience” and assess these measures’ impact on Latinos’ self-rated health status. We model these measures of race as lived experience to test the explanatory power of race, both independently and as an integrated scale, with categorical regression, scaling, and dimensional analyses. Our analyses show that our multiple measures of race have significant and negative effects on Latinos’ self-reported health. Skin color is a dominant factor that impacts self-reported health both directly and indirectly. We then advocate for the utilization of multiple measures of race, adding to those used in our analysis, and their application to research regarding inequities in other health and social outcomes. Our analysis provides important contributions to research across a wide range of health, illness, social, and political disparities for communities of color.
Since its inception in 1999, cognitive radio (CR) has been considered a promising means to use white space channels and thereby make more efficient usage of spectrum. To become the enabling technology for secondary access to TV white spaces (TVWS) requires facing several challenges in radio transceiver devices due to the continuous changes in both bandwidth and transmission frequency. As a consequence, CR requires configurable radio platforms. The development of software-defined radio (SDR) technology has made modern wireless transceivers more versatile, powerful, and portable by performing baseband processing.
As already mentioned in Chapter 1, the United States Federal Communications Commission (FCC) allowed in November 2008 the unlicensed use of the spectrum designated for TV broadcast . Two categories of device use were defined: fixed devices and personal portable devices. Focusing on the mobile (personal portable) devices, the available spectrum is on channels 21–51 (except 37 reserved for wireless microphones) corresponding to the UHF frequency band comprised of between 512 and 698 MHz. Therefore, excluding channel 37, and also 36 and 38 reserved as guard channels, there is the potential for up to 168 MHz of available spectrum whose availability is determined by the presence (or lack thereof) of primary users.
The introduction of cover crops in the intercrop period may provide a broad range of ecosystem services derived from the multiple functions they can perform, such as erosion control, recycling of nutrients or forage source. However, the achievement of these services in a particular agrosystem is not always required at the same time or to the same degree. Thus, species selection and definition of targeted objectives is critical when growing cover crops. The goal of the current work was to describe the traits that determine the suitability of five species (barley, rye, triticale, mustard and vetch) for cover cropping. A field trial was established during two seasons (October to April) in Madrid (central Spain). Ground cover and biomass were monitored at regular intervals during each growing season. A Gompertz model characterized ground cover until the decay observed after frosts, while biomass was fitted to Gompertz, logistic and linear-exponential equations. At the end of the experiment, carbon (C), nitrogen (N), and fibre (neutral detergent, acid and lignin) contents, and the N fixed by the legume were determined. The grasses reached the highest ground cover (83–99%) and biomass (1226–1928 g/m2) at the end of the experiment. With the highest C:N ratio (27–39) and dietary fibre (527–600 mg/g) and the lowest residue quality (~680 mg/g), grasses were suitable for erosion control, catch crop and fodder. The vetch presented the lowest N uptake (2·4 and 0·7 g N/m2) due to N fixation (9·8 and 1·6 g N/m2) and low biomass accumulation. The mustard presented high N uptake in the warm year and could act as a catch crop, but low fodder capability in both years. The thermal time before reaching 30% ground cover was a good indicator of early coverage species. Variable quantification allowed finding variability among the species and provided information for further decisions involving cover crop selection and management.
In this work we study the interfaces between the Mott insulator LaMnO3 (LMO) and the band insulator SrTiO3 (STO) in epitaxially grown superlattices with different thickness ratios and different transport and magnetic behaviors. Using atomic resolution electron energy-loss spectral imaging, we analyze simultaneously the structural and chemical properties of these interfaces. We find changes in the oxygen octahedral tilts within the LaMnO3 layers when the thickness ratio between the manganite and the titanate layers is varied. Superlattices with thick LMO and ultrathin STO layers present unexpected octahedral tilts in the STO, along with a small amount of oxygen vacancies. On the other hand, thick STO layers exhibit undistorted octahedra while the LMO layers present reduced O octahedral distortions near the interfaces. These findings are discussed in view of the transport and magnetic differences found in previous studies.
The aim of this work is to process by equal channel angular pressing (ECAP) a low carbon – triple-alloyed steel containing 0.2% C, 0.5% Cr, 0.6% Ni, 0.2% Mo and 0.8 Mo. The process is performed at room temperature for up to four passes using route Bc with an equivalent strain of ∼0.6 after a single pass. Structure evolution before and after deformation is studied using scanning electron microscopy (SEM) and x-ray diffraction (XRD) and mechanical properties are assessed by microhardness and tensile testing. A significant improvement of the mechanical properties is found with increasing number of ECAP passes. Micro-hardness increases from 216 HV for the initial sample to 302 HV after four passes and tensile strength increases to 1200 MPa compared with 430 MPa prior to ECAP. X-ray diffraction and SEM analysis show changes in the original ferritic-perlitic structure through ferrite grain refinement and the deformation of perlite. This nickel-chromium-molybdenum alloy is used in manufacturing as gear material, and when it is hardened and formed through carburizing or boronizing it can be used to make hard-wearing machine parts. However, the ECAP process has not been used to harden this steel and to change its structure to obtain better mechanical performance.
The present study aimed to evaluate the nutritional status of pregnant women in Colombia and the associations between gestational BMI and sociodemographic and gestational characteristics.
Cross-sectional study. A secondary analysis was made of data from the 2005 Demographic and Health Survey of Colombia.
Pregnant adolescents aged 13–19 years (n 430) and pregnant women aged 20–49 years (n 1272).
The gestational BMI and sociodemographic characteristics of the adolescents differed from those of the pregnant adult women. Thirty-one per cent of the adolescents were underweight for gestational age, compared with 14·5 % of the adult women. Eighteen per cent of adolescents were overweight for gestational age, in contrast to 37·3 % of adult women. The overall prevalence of anaemia was 44·7 % and the prevalence of low serum ferritin was 38·8 %. Women within the high quintiles of the wealth index (prevalence odds ratio (POR) = 0·56; 95 % CI 0·34, 0·91, P < 0·02) had lower odds of being underweight. Women who received prenatal care (POR = 2·17; 95 % CI 1·48, 3·09, P < 0·001) and were multiparous (POR = 2·10; 95 % CI 1·43, 3·15, P < 0·0 0 1) had higher odds of being overweight. Women in extended families (POR = 0·63; 95 % CI 0·50, 0·95, P < 0·025) had lower odds of being overweight.
Underweight in pregnant adolescents and overweight in adult women coexist as a double burden in Colombia. Factors associated with malnutrition among pregnant women and adolescents should be considered for future interventions in countries experiencing nutritional transition.
An efficient synthetic route for the synthesis of carcerands derived from tetramethylchlorocavitands and its tetraesters derivative were synthesized. A large-scale preparation was achieved in good yield. These carcerands are in bridging unit between oxygen atoms, i.e. contains a 3,5 dihydroxybencyl alcohol units. 1H, and 13C NMR in solution, FTIR, UV-vis spectroscopy, MS-FAB+ spectrometry and elemental analysis confirmed the structure of this carcerands.
Research on the relation between Belief Revision and Argumentation has always been fruitful in both directions: some argumentation formalisms can be used to define belief change operators, and belief change techniques have also been used for modeling the dynamics of beliefs in argumentation formalisms. In this paper, we give a historical perspective on how belief revision has evolved in the last three decades, and how it has been combined with argumentation. First, we will recall the foundational works concerning the links between both areas. On the basis of such insights, we will present a conceptual view on this topic and some further developments. We offer a glimpse into the future of research in this area based on the understanding of argumentation and belief revision as complementary, mutually useful disciplines.
Discordances exist in epidemiological studies regarding the association between the intake of nutrients and death and disease. We evaluated the social and health profile of persons who consumed olive oil in a prospective population cohort investigation (Pizarra study) with a 6-year follow-up. A food frequency questionnaire and a 7 d quantitative questionnaire were administered to 538 persons. The type of oil used in food preparation was determined by direct measurement of the fatty acids in samples obtained from the kitchens of the participants at baseline and after follow-up for 6 years. The fatty acid composition of the serum phospholipids was used as an endogenous marker of the type of oil consumed. Total fat intake accounted for a mean 40 % of the energy (at baseline and after follow-up). The concordance in intake of MUFA over the study period was high. The fatty acid composition of the serum phospholipids was significantly associated with the type of oil consumed and with fish intake. The concentration of polar compounds and polymers, indicative of degradation, was greater in oils from the kitchens where sunflower oil or refined olive oil was used, in oils used for deep frying and in oils that had been reused for frying five times or more. Consumption of olive oil was directly associated with educational level. Part of the discordance found in epidemiological studies between diet and health may be due to the handling of oils during food preparation. The intake of olive oil is associated with other healthy habits.