The CWKB particle production and classical condensate in de Sitter spacetime

The complex time WKB approximation is an effective tool in studying particle production in curved spacetime. We use it in this work to understand the formation of classical condensate in expanding de Sitter spacetime. The CWKB leads to the emergence of thermal spectrum that depends crucially on horizons (as in de Sitter spacetime) or observer dependent horizons (as in Rindler spacetime). A connection is sought between the horizon and the formation of classical condensate. We concentrate on de Sitter spacetime and study the cosmological perturbation of $k=0$ mode with various values of $m/H_0$. We find that for a minimally coupled free scalar field for $m^2/H_0^2<2$, the one-mode occupation number grows more than unity soon after the physical wavelength of the mode crosses the Hubble radius and soon after diverges as $N(t)\sim O(1)[\lambda_{phys}(t)/{H_0^{-1}}]^{2\sqrt{\nu^2-1/4}}$, where $\nu\equiv (9/4 -m^2/{H_0^2})^{1/2}$. The results substantiates the previous works in this direction. We also find the correct oscillation and behaviour of $N(z)$ at small $z$ from a single expression using CWKB approximation for various values of $m/H_0$. We also discuss decoherence in relation to the formation of classical condensate. We also find that the squeezed state formalism and CWKB method give identical results.Comment: 19 pages, revtex, 5 figure

Targetability of hyaluronic acid nanogel to cancer cells: In vitro and in vivo studies

We have, in previous work developed, characterized and evaluated the biocompatibility of an engineered hyaluronic acid nanogel. Here we assess the targetability of a hyaluronic acid nanogel towards CD44 overexpressing cells, in vitro and in vivo. Results obtained by flow cytometry and confocal fluorescence microscopy shows that nanogel is greatly internalized by non-small cancer lung cells (A549 cells), that overexpress CD44 receptors. The biodistribution and tumor targetability of the nanogel labelled with a near-infrared (NIR) probe were performed, in mice, through a non-invasive imaging system. Results revealed nanogel high targetability towards an induced subcutaneous A549 tumor. Nanogels pharmacokinetics was evaluated also in healthy animals, and Alexa Fluor 680 labelled nanogel exhibited higher accumulation in liver, kidneys and skin. Also, a comparative biodistribution study was performed, using two NIR imaging probes, Cy5.5 and Alexa Fluor 680.The authors thank the FCT Strategic Project of UID/BIO/04469/ 2013 unit, the project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124FEDER-027462) and the Project “BioHealth - Biotechnology and Bioengineering approaches to improve health quality”, Ref. NORTE07-0124-FEDER-000027, co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. We would like to acknowledge also the support of FCT for the PhD grant reference SFRH/BD/61516/2009. We would also like to thank Bioimaging department on Molecular Medicine Institute (IMM) in Lisbon, namely Dr. José Rino and Dr. António Temudo. Also thank the animal facilities in IMM (Lisbon), specially Dra. Dolores Bonaparte and Dra. Joana Marques. Also, we would like to acknowledge the special contribution of Professor Fatima Baltazar in ICVS (Braga) for kindly grant us CFBE and A549 cell lines.info:eu-repo/semantics/publishedVersio

Chromosome identification in the Andean common bean accession G19833 (Phaseolus vulgaris L., Fabaceae)

Characterization of all chromosomes of the Andean G19833 bean genotype was carried out by fluorescent in situ hybridization. Eleven single-copy genomic sequences, one for each chromosome, two BACs containing subtelomeric and pericentromeric repeats and the 5S and 45S ribosomal DNA (rDNA) were used as probes. Comparison to the Mesoamerican accession BAT93 showed little divergence, except for additional 45S rDNA sites in four chromosome pairs. Altogether, the results indicated a relative karyotypic stability during the evolution of the Andean and Mesoamerican gene pools of P. vulgaris

Managing affect in learners' questions in undergraduate science

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Society for Research into Higher Education.This article aims to position students' classroom questioning within the literature surrounding affect and its impact on learning. The article consists of two main sections. First, the act of questioning is discussed in order to highlight how affect shapes the process of questioning, and a four-part genesis to question-asking that we call CARE is described: the construction, asking, reception and evaluation of a learner's question. This work is contextualised through studies in science education and through our work with university students in undergraduate chemistry, although conducted in the firm belief that it has more general application. The second section focuses on teaching strategies to encourage and manage learners' questions, based here upon the conviction that university students in this case learn through questioning, and that an inquiry-based environment promotes better learning than a simple ‘transmission’ setting. Seven teaching strategies developed from the authors' work are described, where university teachers ‘scaffold’ learning through supporting learners' questions, and working with these to structure and organise the content and the shape of their teaching. The article concludes with a summary of the main issues, highlighting the impact of the affective dimension of learning through questioning, and a discussion of the implications for future research

Squeezed States of the Generalized Minimum Uncertainty State for the Caldirola-Kanai Hamiltonian

We show that the ground state of the well-known pseudo-stationary states for the Caldirola-Kanai Hamiltonian is a generalized minimum uncertainty state, which has the minimum allowed uncertainty $\Delta q \Delta p = \hbar \sigma_0/2$, where $\sigma_0 (\geq 1)$ is a constant depending on the damping factor and natural frequency. The most general symmetric Gaussian states are obtained as the one-parameter squeezed states of the pseudo-stationary ground state. It is further shown that the coherent states of the pseudo-stationary ground state constitute another class of the generalized minimum uncertainty states.Comment: RevTex4, 9 pages, no fingure; to be published in Journal of Physics

Determinação de paclobutrazol em solo por cromatografia líquida de alta eficiência.

Este trabalho descreve um método para determinação de paclobutrazol em amostras de solo. A extração foi feita em metanol e as análises por cromatografia líquida de alta eficiência (CLAE), usando coluna de fase-reversa, C-18, fase móvel metanol/água 60:40, v/v, detecção e quantificação a 220 nm. Os seguintes parâmetros de validação foram obtidos: limite de detecção do método de 0,010 mg kg-1, limite de quantificação do método de 0,020 mg kg-1, linearidade de 0,100?5,00 mg L-1 (r2 ? 0,999); recuperação de 70 a 99%, precisão intermediária (%RSD) < 13%, para paclobutrazol. O método mostrou ser simples, eficiente e confiável para a determinação de resíduos de paclobutrazol em amostras de solo

Effect of active video games on the balance of healthy elderly: systematic review

Introduction: Active video games are an important parcel of our society. For many years this type of entertainment has been looked at as just a ludic device. More recently this device has been used as a form of therapeutic intervention. Objectives: Review in a systematic way the available scientific evidence about the efficacy of active video games, in balance on healthy elderly people and if necessary propose further investigation. Methodology: Were included experimental studies in English, French and Spanish, with an intervention based on active video games to promote balance on healthy elderly people. The research took place on the following databases: PubMed, PEDro, Science Direct, Cochrane, Web of Knowlegde, EBSCO, Taylor & Francis, Springer and Wiley. The article selection was made by five independent reviewers. Of the 1434 initial articles were selected nine. This final sample was read and analysed using PEDro’s scale. Results: All the studies used balance as the main variable and although using different evaluation methods they showed significant differences in the experimental groups. Conclusion: After analyzing the results it’s possible to observe that this type of intervention is effective in improving balance in healthy elderly. However the limitations of the studies have to be considered and the results cannot be applied to the general population. It´s essential to continue the investigation about this subject creating more evidence with strong experimental relevance.N/