Rabi Oscillations and Few-Level Approximations in Time-Dependent Density Functional Theory

The resonant interaction of laser light with atoms is analyzed from the time-dependent density functional theory perspective using a model Helium atom which can be solved exactly. It is found that in exact-exchange approximation the time-dependent dipole shows Rabi-type oscillations of its amplitude. However, the time-dependent density itself is not well described. These seemingly contradictory findings are analyzed. The Rabi-type oscillations are found to be essentially of classical origin. The incompatibility of time-dependent density functional theory with few-level approximations for the description of resonant dynamics is discussed.Comment: 4 pages, 4 figures, REVTeX-styl

Avaliação dos impactos sociais de tecnologias agropecuárias: geração de empregos.

A Embrapa, como uma instituição de pesquisa, utiliza para medir a geração de impactos de uma tecnologia, metodologias que reflitam os impactos de seus produtos, como é o caso do método do excedente econômico, e os Ambitec’s (Sistema de Avaliação de Impacto de Inovações Tecnológicas Agropecuárias), que ajudam a levantar impactos econômicos, sociais e ambientais das tecnologias, aplicada em três etapas: 1) levantamento e coleta de dados, como alcance, delimitação e adotantes; 2) aplicação de questionários com geração de dados quantitativos e 3) análise e interpretação dos índices gerados. O objetivo desse trabalho é mostrar a importância da avaliação dos impactos das tecnologias sobre o emprego, com o intuito de valorizar este componente dos impactos sociais. Para operacionalizar a avaliação de impactos sociais sobre os empregos gerados pela adoção de tecnologias, definiu-se a necessidade de medir o número de empregos adicionais, em toda a cadeia produtiva, resultantes da adoção de uma dada tecnologia, comparativamente à situação dos empregos na tecnologia anterior, e agora substituída pela tecnologia Embrapa. A estimativa do número de empregos gerados pelas tecnologias é importante sob dois aspectos. Primeiro, permite que a equipe de avaliação de impactos conheça todo o potencial de geração de emprego da tecnologia, verificando qual elo da cadeia produtiva poderá ser mais impactado. Em segundo lugar, destaca-se a questão da visibilidade, pois as estimativas de empregos gerados por tecnologias, são divulgadas no Balanço Social da Embrapa, evidenciando pesquisadores, equipe de avaliação de impactos, e a própria Embrapa. Assim, a avaliação dos impactos sobre o emprego, a partir do desenvolvimento de tecnologias constitui uma necessidade e representa um avanço no entendimento dos resultados oriundos dos avanços tecnológicos, além de uma constatação de que a geração de empregos no campo afeta não só o espaço local mas também toda uma cadeia produtiva relacionada ao campo. Palavras-Chave: metodologia – emprego – tecnologias – Embrap

High-quality Phase-Shifted Bragg grating sensor inscribed with only one laser pulse in a polymer optical fiber

We present the first phase-shifted polymer optical fiber Bragg grating sensor inscribed with only one KrF laser pulse. The phase shift defect was created directly during the grating inscription process by placing a very narrow blocking aperture, in the center of the UV beam. One laser pulse with a duration of 15 ns and energy 6.3 mJ is adequate to introduce a refractive index change of 0.69×10-4 in the fiber core. The high-quality produced Bragg grating structure rejects 16.3 dB transmitted power, thus providing 97.6% reflectivity, which is well suited for photonic applications. The transmission notch depth is about 10 dB and very sharp notches of 3 dB width ranging from 14 pm is reported. The temperature, strain, and pressure response of the sensor has been characterized showing promising results in applications that require high-precision measurements. The ability to inscribe these high-quality sensors effectively can significantly reduce their production cost in industry

Análise emergética dos sistemas de pesca no pantanal

Os sistemas de pesca (profissional-artesanal, subsistência e amadora) constituem atividades econômicas muito importantes no Pantanal. Por meio da análise emergética será avaliado seu desempenho. As primeiras análises revelam que a pesca profissional artesanal utiliza amplamente os recursos naturais, com pouca entrada de recursos econômicos externos, e o peixe é vendido para turistas e comunidade local; os fluxos são internos ao ecossistema e as externalidades são mínimas. A pesca de subsistência mostra ser auto-suficiente. A pesca amadora, por outro lado, requer maior infra-estrutura, as articulações com a economia local são limitadas e gera vários tipos de externalidades negativas. In the “Pantanal”, a very big Brazilian wetland, fishery is an important economic activity that is carried out under three modalities: professional-artisanal, subsistence and touristic. Their ecological and thermodynamic performance will be studied using the emergy methodology. As first stage of this analysis, it was realized an information recovery in order to prepare the systems diagrams. The diagrams revealed the dependence of each one of fishery systems with local and external resources. Subsistence fishery is sustainable but doesn’t have product for sale. Professional-artisanal fishery interacts with different markets and uses a small quantity of external inputs. Touristic fishery depends on infra-structure investments and do not interact in adequate form with local economy

Optical properties of titanium oxycarbide thin films

The optical properties of TiC x O y thin films, deposited by reactive dc magnetron sputtering at different oxygen flow, were investigated by spectroscopic ellipsometry in the energy range of 0.75–4.5 eV. The dielectric functions measured in the energy range of intraband transitions were analyzed using the classical Drude theory. These results show that free plasma energy and the damping constant of the films depend strongly on film stoichiometry and on their oxygen content. The interband contribution to the optical conductivity of these films is in good agreement with the optical conductivity obtained from first principles calculations based on density functional theory. Both the experimental and the calculated results show that it is possible to significantly modify the optical properties of titanium oxycarbide by adjusting the oxygen content.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência , Tecnologia, Inovação” – CONC-REEQ/443/EEI/2005, PTDC/CTM/69362 e SFRH/BD/27569/200

Radiocarbon and blue optically stimulated luminescence chronologies of the Oitavos consolidated dune (Western Portugal)

The dune of Oitavos, the underlying paleosol, and Helix sp. gastropod shells found within the paleosol were dated using a combination of radiocarbon and blue optically stimulated luminescence (OSL). The organic component of the paleosol produced a significantly older age (~20,000 cal BP) than the OSL age measurement (~15,000 yr), while 14C age measurements on the inorganic component and the gastropods produced ages of ~35,000 yr and ~34,000 yr, respectively. Rare-earth element analyses provide evidence that the gastropods incorporate geological carbonate, making them an unreliable indicator of the age of the paleosol. We propose that the 14C age of the small organic component of the paleosol is also likely to be unreliable due to incorporation of residual material. The OSL age measurement of the upper paleosol (~15,000 yr) is consistent with the age for the base of the dune (~14,500 yr). The younger OSL age for the top of the dune (~12,000 yr) suggests that it was built up by at least 2 sand pulses or that there was a remobilization of material at the top during its evolution, prior to consolidation

Mixture models for distance sampling detection functions

Funding: EPSRC DTGWe present a new class of models for the detection function in distance sampling surveys of wildlife populations, based on finite mixtures of simple parametric key functions such as the half-normal. The models share many of the features of the widely-used “key function plus series adjustment” (K+A) formulation: they are flexible, produce plausible shapes with a small number of parameters, allow incorporation of covariates in addition to distance and can be fitted using maximum likelihood. One important advantage over the K+A approach is that the mixtures are automatically monotonic non-increasing and non-negative, so constrained optimization is not required to ensure distance sampling assumptions are honoured. We compare the mixture formulation to the K+A approach using simulations to evaluate its applicability in a wide set of challenging situations. We also re-analyze four previously problematic real-world case studies. We find mixtures outperform K+A methods in many cases, particularly spiked line transect data (i.e., where detectability drops rapidly at small distances) and larger sample sizes. We recommend that current standard model selection methods for distance sampling detection functions are extended to include mixture models in the candidate set.Publisher PDFPeer reviewe

Teores e conteúdo de NPK em folhas de alfavaca-cravo em função da adubação orgânica e épocas de corte.

Estudou-se o efeito da adubação orgânica e épocas de corte nos teores e extração de NPK em alfavaca-cravo nas condições de Botucatu - SP. Utilizou-se 04 doses de esterco de poedeira curtido (tratamentos principais) e 04 épocas de corte (outono, inverno e primavera do ano de 2001 e verão de 2002)

Educational Level Is Related to Physical Fitness in Patients with Type 2 Diabetes - A Cross-Sectional Study.

Low educational level (EL) and low physical fitness are both predictors of increased morbidity and mortality in patients with type 2 diabetes. It is unknown if EL is related to physical fitness. This would have important implication for the treatment approach of patients of low EL. In 2011/12, we invited participants of a new nationwide Swiss physical activity program for patients with type 2 diabetes to participate in this study. EL was defined by self-report and categorized as low (mandatory education), middle (professional education) or high (high school/university). Physical fitness was determined using 5 validated measures that assessed aerobic fitness, functional lower limb muscle strength, walking speed, balance and flexibility. Potential confounder variables such as other socio-cultural factors, physical activity level, body composition, diabetes-related parameters and complications/co-morbidities as well as well-being were assessed. All invited 185 participants (mean age 59.6 ±9.8 yrs, 76 women) agreed to be included. Of all patients, 23.1% had a low, 32.7% a middle and 44.2% a high EL; 41.8% were professionally active. The study population had a mean BMI of 32.4±5.2 kg/m2 and an HbA1c of 7.3±1.3%. The mean diabetes duration was 8.8±7.4 years. In the baseline assessment, higher EL was associated with increased aerobic fitness, increased functional lower limb muscle strength, and increased walking speed using linear regression analysis (values for low, middle and high EL, respectively: 91.8 ± 27.9, 116.4 ± 49.7 and 134.9 ± 60.4 watts for aerobic fitness (p = 0.002), 15 ± 4.7, 13.9 ± 2.7, 12.6 ± 2.9 seconds for strength (p = 0.001) and 8.8 ± 1.6, 8.3 ± 1.4, 7.8 ± 1.4 seconds for walking speed (p = 0.004)). These associations were independent of potential confounders. Overall, aerobic fitness was 46%, functional limb muscle strength 16%, and walking speed 11% higher in patients of high compared to those of low EL. EL was not related to balance or flexibility. A main strength of the present study is that it addresses a population of importance and a factor (EL) whose understanding can influence future interventions. A second strength is its relatively large sample size of a high-risk population. Third, unlike studies that have shown an association between self-reported fitness and educational level we assessed physical fitness measures by a quantitative and validated test battery using assessors blinded to other data. Another novelty is the extensive evaluation of the role of many relevant confounder variables. In conclusion, we show that in patients with type 2 diabetes EL correlates favorably and independently with important health-related physical fitness measures such as aerobic fitness, walking speed, and lower limb strength. Our findings underline that diabetic patients with low EL should be specifically encouraged to participate in physical activity intervention programs to further reduce social disparities in healthcare. Such programs should be structured and integrate the norms, needs and capacities (financial, time, physical capacities and self-efficacy) of this population, and their effectiveness should be tested in future studies. University of Lausanne clinicaltrials.gov NCT01289587