432 research outputs found
Collective oscillations of a Fermi gas in the unitarity limit: Temperature effects and the role of pair correlations
We present detailed measurements of the frequency and damping of three
different collective modes in an ultracold trapped Fermi gas of Li atoms
with resonantly tuned interactions. The measurements are carried out over a
wide range of temperatures. We focus on the unitarity limit, where the
scattering length is much greater than all other relevant length scales. The
results are compared to theoretical calculations that take into account Pauli
blocking and pair correlations in the normal state above the critical
temperature for superfluidity. We show that these two effects nearly compensate
each other and the behavior of the gas is close to the one of a classical gas.Comment: 8 pages, 5 figure
Pairing-gap, pseudo-gap, and no-gap phases in the radio-frequency spectra of a trapped unitary 6Li gas
Radio frequency spectra of a trapped unitary 6Li gas are reported and
analyzed in terms of a theoretical approach that includes both final-state and
trap effects. Final-state effects play a crucial role in evidencing two main
peaks both above and below the critical temperature Tc as being associated with
two distinct phases that reside in different trap regions. These are the
pairing-gap and pseudo-gap phases below Tc, which evolve into the pseudo-gap
and no-gap phases above Tc. In this way, a long standing puzzle about the
interpretation of rf spectra for 6Li in a trap is solved.Comment: 5 pages, 6 figures (final version
Moving from a Product-Based Economy to a Service-Based Economy for a More Sustainable Future
Traditionally, economic growth and prosperity have been linked with the availability, production and distribution of tangible goods as well as the ability of consumers to acquire such goods. Early evidence regarding this connection dates back to Adam Smith's Wealth of Nations (1776), in which any activity not resulting in the production of a tangible good is characterized as unproductive of any value." Since then, this coupling of economic value and material production has been prevalent in both developed and developing economies throughout the world. One unintended consequence of this coupling has been the exponential increase in the amount of solid waste being generated. The reason is that any production and consumption of material goods eventually generates the equivalent amount of (or even more) waste. Exacerbating this problem is the fact that, with today's manufacturing and supply chain management technologies, it has become cheaper to dispose and replace most products rather than to repair and reuse them. This has given rise to what some call a disposable society." To put things in perspective: In 2012 households in the U.K. generated approximately 22 thousand tons of waste, which amounted to 411 kg of waste generated per person (Department for Environment, Food & Rural Affairs, 2015). During the same time period, households in the U.S. generated 251 million tons of waste, which is equivalent to a person generating approximately 2 kg of waste every day (U.S. Environmental Protection Agency, 2012). Out of these 251 million tons of total waste generated, approximately 20% of the discarded items were categorized as durable goods. The disposal of durable goods is particularly worrisome because they are typically produced using material from non- renewable resources such as iron, minerals, and petroleum-based raw materials
Methodological design for the assessment of physical activity and sedentary time in eight Latin American countries - The ELANS study.
Worldwide studies of physical activity and sedentary time have historically under-represented low- and middle-income countries due to the lack of surveillance data. The purpose of this paper is to describe the methods and procedures used for the assessment of physical activity and sedentary time in the Latin American Study of Nutrition and Health (Estudio Latinoamericano de Nutrición y Salud; ELANS). ELANS is a multicentre, cross-sectional and surveillance study of a nationally representative sample from eight Latin American countries: Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela. Two instruments were used to evaluate different domains and intensities of physical activity and sedentary time: self-reported data and a triaxial accelerometer (model GT3X+). ELANS will generate important self-reported and objective information for the Latin American populations, namely:•evidence on the distribution of physical activity and sedentary time across population subgroups (e.g. sex, age, socioeconomic- and educational level). These sets of information will increase the evidence base and can help to inform future intervention strategies in Latin America;•self-reported and objective information on physical activity and sedentary time
INVENTORY OF TOURISM RESOURCES OF THE MOUNTAIN AREA OF TEXCOCO, STATE OF MEXICO
Objective. To elaborate an inventory of tourism resources identified in the mountain area of Texcoco, which serve as an instrument for planning and organizing the local tourism system.
Design/Methodology/Approach. We considered the application of a survey to the auxiliary authorities, as well as to local and external actors that would allow contextualizing the tourism dynamics in the area. The task was supported by field trips applying the ethnographic method. From the collected data, eight localities were selected within the characteristics, a greater number of tourism resources were identified.
Results. It was determined that some of the selected localities have sufficient attributes to potentiate some of their resources as a strategy for local development.
Limitations/Implications. The restriction to access information in local offices of the municipal government limited the approach to some resources; thus, self-reported data had to be constructed through the perception of some individuals.
Conclusions. It is necessary to develop tourism land-planning instruments through mechanisms of management that include training for local actors on various topics for the sustainable use of tourism resources
Anthropometry, dietary intake, physical activity and sitting time patterns in adolescents aged 15-17 years: an international comparison in eight Latin American countries
BACKGROUND: Although there is high prevalence of obesity and other cardiovascular risk factors among Latin American adolescents, there is limited evidence on dietary intake and physical activity (PA) patterns in this population. Therefore, we characterized anthropometry, dietary intake, PA and sitting time (ST) in adolescents aged 15-17 years from eight Latin American countries. METHODS: Six hundred seventy-one adolescents (41.4% girls) from the Latin American Study of Nutrition and Health (ELANS) were included. Nutritional status was classified by four BMI (kg/m2) categories. Waist circumference (WC) was categorized as above or below thresholds. Dietary intake was assessed through two non-consecutive 24-h dietary recalls. PA and ST were measured using the International Physical Activity Questionnaire (IPAQ). We calculated overall and country-specific estimates by sex and tested for differences between boys and girls. RESULTS: Differences in the prevalence of overweightness (15.1 and 21.6%) and obesity (8.5 and 6.5%) between boys and girls, respectively, were statistically insignificant (p = 0.059). Average energy intake was 2289.7 kcal/day (95% CI: 2231-2350) for boys and 1904.2 kcal/day (95% CI: 1840-1963) for girls (p  0.05 for all outcomes). There was no statistically significant difference in the prevalence of total energy (TE) saturated fat and added sugar (>10% of TE) between girls and boys (49.6% versus 44.8 and 81.7% versus 76.1%, respectively). Prevalence of physical inactivity was 19% in boys and 43.7% in girls (p  0.05). CONCLUSIONS: These findings highlight the high prevalence of poor dietary intake and physical inactivity in adolescents from Latin American countries. Therefore, effective and sustainable strategies and programmes are needed that promote healthier diets, regular PA and reduce ST among Latin American adolescents. TRIAL REGISTRATION: Clinical Trials NCT02226627. Retrospectively registered on August 27, 2014
Citrus junos as a host of citrus bacterial canker
Following a request from the European Commission, the European Food Safety Authority (EFSA) Plant Health (PLH) Panel analysed a dossier submitted by the Japanese authorities in order to clarify the host status of Citrus junos with regard to Xanthomonas citri pv. citri and Xanthomonas citri pv. aurantifolii, causal agents of citrus bacterial canker, and to indicate whether C. junos fruit could represent a pathway for the introduction of citrus bacterial canker into the European Union. In a previous opinion in the year 2014, the EFSA PLH Panel concluded that commercial fresh citrus fruit is generally pathway and that no commercially important Citrus species or variety can be considered as immune to citrus bacterial canker. In the current assessment, the EFSA PLH Panel analysed the two scientific papers provided by the Japanese authorities, as well as 16 additional papers identified through a systematic literature review. The PLH Panel considered that the conclusions of its previous opinion remain valid and that convergent lines of evidence provide sufficient demonstration that C. junos is a host of X. citri pv. citri and X. citri pv. aurantifolii. Therefore, there is no reason to consider the C. junos fruit differently from other citrus species. Consequently, the assessment of the general citrus fruit pathway from the 2014 opinion still applies. Uncertainties on these conclusions are a result of the scarce scientific evidence published on this subject in addition to the methodological and reporting limitations of the published papers
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