584 research outputs found
Infra-Red Surface-Plasmon-Resonance technique for biological studies
We report on a Surface-Plasmon-Resonance (SPR) technique based on Fourier
-Transform - Infra - Red (FTIR) spectrometer. In contrast to the conventional
surface plasmon technique, operating at a fixed wavelength and a variable angle
of incidence, our setup allows the wavelength and the angle of incidence to be
varied simultaneously. We explored the potential of the SPR technique in the
infrared for biological studies involving aqueous solutions. Using computer
simulations, we found the optimal combination of parameters (incident angle,
wavelength) for performing this task. Our experiments with physiologically
important glucose concentrations in water and in human plasma verified our
computer simulations. Importantly, we demonstrated that the sensitivity of the
SPR technique in the infrared range is not lower and in fact is even higher
than that for visible light. We emphasize the advantages of infra red SPR for
studying glucose and other biological molecules in living cells.Comment: 8 pages,8 figure
Reversing conditional orderings
We analyze some specific aspects concerning conditional orderings and relations among them. To this purpose we define a suitable concept of reversed conditional ordering and prove some related results. In particular we aim to compare the univariate stochastic orderings ≤ st, ≤ hr, and ≤ lr in terms of differences among different notions of conditional orderings. Some applications of our result to the analysis of positive dependence will be detailed. We concentrate attention to the case of a pair of scalar random variables X, Y . Suitable extensions to multivariate cases are possible
Predatory Bacteria: A Potential Ally against Multidrug-Resistant Gram-Negative Pathogens
Multidrug-resistant (MDR) Gram-negative bacteria have emerged as a serious threat to human and animal health. Bdellovibrio spp. and Micavibrio spp. are Gram-negative bacteria that prey on other Gram-negative bacteria. In this study, the ability of Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus to prey on MDR Gram-negative clinical strains was examined. Although the potential use of predatory bacteria to attack MDR pathogens has been suggested, the data supporting these claims is lacking. By conducting predation experiments we have established that predatory bacteria have the capacity to attack clinical strains of a variety of ß-lactamase-producing, MDR Gram-negative bacteria. Our observations indicate that predatory bacteria maintained their ability to prey on MDR bacteria regardless of their antimicrobial resistance, hence, might be used as therapeutic agents where other antimicrobial drugs fail. © 2013 Kadouri et al
Generalized Ladder Operators for Shape-invariant Potentials
A general form for ladder operators is used to construct a method to solve
bound-state Schr\"odinger equations. The characteristics of supersymmetry and
shape invariance of the system are the start point of the approach. To show the
elegance and the utility of the method we use it to obtain energy spectra and
eigenfunctions for the one-dimensional harmonic oscillator and Morse potentials
and for the radial harmonic oscillator and Coulomb potentials.Comment: in Revte
On the possible influence of radon and aerosol injection on the atmosphere and ionosphere before earthquakes
International audienceA model of the generation of pulses of local electric fields with characteristic time scales of 1?10 min is considered for atmospheric conditions above fracture regions of earthquakes. In the model, it is proposed that aerosols, increased ionization velocity and upstreaming air flows occur at night-time conditions. The pulses of local electric fields cause respective pulses of infrared emissions. But infrared emissions with time scales of 1?10 min were not observed up to now experimentally. The authors think, that the considered non-stationary field and radiation effects might be a new-type of applicable earthquake indicators and ask to perform special earth-based and satellite observations of the night-time atmosphere in seismoactive fracture regions
Detecting Sarcasm in Multimodal Social Platforms
Sarcasm is a peculiar form of sentiment expression, where the surface
sentiment differs from the implied sentiment. The detection of sarcasm in
social media platforms has been applied in the past mainly to textual
utterances where lexical indicators (such as interjections and intensifiers),
linguistic markers, and contextual information (such as user profiles, or past
conversations) were used to detect the sarcastic tone. However, modern social
media platforms allow to create multimodal messages where audiovisual content
is integrated with the text, making the analysis of a mode in isolation
partial. In our work, we first study the relationship between the textual and
visual aspects in multimodal posts from three major social media platforms,
i.e., Instagram, Tumblr and Twitter, and we run a crowdsourcing task to
quantify the extent to which images are perceived as necessary by human
annotators. Moreover, we propose two different computational frameworks to
detect sarcasm that integrate the textual and visual modalities. The first
approach exploits visual semantics trained on an external dataset, and
concatenates the semantics features with state-of-the-art textual features. The
second method adapts a visual neural network initialized with parameters
trained on ImageNet to multimodal sarcastic posts. Results show the positive
effect of combining modalities for the detection of sarcasm across platforms
and methods.Comment: 10 pages, 3 figures, final version published in the Proceedings of
ACM Multimedia 201
Does survey respondents' immigrant background affect the measurement and prediction of immigration attitudes ? An illustration in two steps
While most survey research on immigration attitudes routinely excludes respondents with an immigrant background, empirical justifications for doing so are rarely provided. Yet it is crucial to examine whether respondents with an immigrant background can be included in the analysis, as excluding them with no further consideration would ignore the opinion of a considerable share of multicultural societies. With multigroup analyses on Swiss data we illustrated how to evaluate whether both the measurement and the prediction of immigration attitudes are invariant across natives and individuals with an immigrant background. The slight revealed differences did not justify the exclusion of respondents with an immigrant background. The paper concludes by discussing ways of addressing these differences in measurement and prediction
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