364 research outputs found
Extrema bounds for the soft Pomeron intercept
By using an extended Regge parametrization and taking into account the
discrepancies in the high-energy pp and p(bar)p total cross section data, in
both accelerator and cosmic-ray regions, we estimate extrema bounds for the
soft Pomeron intercept. First we consider two ensembles of data with either the
CDF or the E710 and E811 results for the p(bar)p total cross section at 1.8
TeV, from which we obtain the bounds 1.102 and 1.081, respectively. These
ensembles are then combined with the highest and lowest estimations for the pp
total cross section from cosmic-ray experiments (6-40 TeV), leading to the
upper and lower bounds 1.109 and 1.082, respectively. The effects of
simultaneous fits to total cross sections and the rho parameter, individual
fits to total cross sections, and the influence of the subtraction constant in
the dispersion relations are also presented. Our global results favor the E710
and E811 data.Comment: 7 pages, 7 figures, aps-revtex, to be published in Physics Letters
Total Hadronic Cross Section and the Elastic Slope: An Almost Model-Independent Connection
An almost model-independent parametrization for the ratio of the total cross
section to the elastic slope, as function of the center of mass energy, is
introduced. The analytical result is based on the approximate relation of this
quantity with the ratio of the elastic to total cross section and empirical
fits to the data from proton-proton scattering above 10 GeV, under the
conditions of asymptotic unitarity and the black-disk limit. This
parametrization may be useful in studies of extensive air showers and the
determination of the proton-proton total cross section from proton-air
production cross section in cosmic-ray experiments.Comment: 15 pages, 4 figures, v4: few typos corrected, final version to be
published in Nucl. Phys.
A versatile reactor for continuous monitoring of biofilm properties in laboratory and industrial conditions
Aims: The understanding of the dynamics of surface microbial colonization with concomitant monitoring of biofilm formation requires the development of biofilm reactors that enable direct and real-time evaluation under different hydrodynamic conditions.
Methods and Results: This work proposes and discusses a simple flow cell reactor that provides a means to monitoring biofilm growth by periodical removing biofilm-attached slides for off-line, both non-destructive and destructive biofilm analyses. This is managed without the stoppage of the flow, thus reducing the contamination and the disturbance of the biofilm development. With this flow cell, biofilm growth and respiratory activity can be easily followed, either in well-defined laboratory conditions or in an industrial environment.
Conclusions, Significance and Impact of the Study: The reproducible and typical biofilm development curves obtained, validated this flow cell and confirmed its potential for different biofilm-related studies, which can include biocidal treatment.Instituto de Biotecnologia e Química Fina(IBQF)
Phenomenological analysis connecting proton-proton and antiproton-proton elastic scattering
Based on the behavior of the elastic scattering data, we introduce an almost
model-independent parametrization for the imaginary part of the scattering
amplitude, with the energy and momentum transfer dependences inferred on
empirical basis and selected by rigorous theorems and bounds from axiomatic
quantum field theory. The corresponding real part is analytically evaluated by
means of dispersion relations, allowing connections between particle-particle
and particle-antiparticle scattering. Simultaneous fits to proton-proton and
antiproton-proton experimental data in the forward direction and also including
data beyond the forward direction, lead to a predictive formalism in both
energy and momentum transfer. We compare our extrapolations with predictions
from some popular models and discuss the applicability of the results in the
normalization of elastic rates that can be extracted from present and future
accelerator experiments (Tevatron, RHIC and LHC).Comment: 17 pages, 17 figures, to appear in Eur. Phys. J.
An integrated modelling approach for the seismic collapse assessment of masonry towers
Failure of tall slender masonry structures during earthquakes often involves partial collapse of the structure well-above ground level. Consequently, the elastic response of the structure needs to be considered, which often requires modal analysis using finite element models — the generation of which can be labour-intensive and time-consuming. This paper presents a new integrated modelling approach which combines finite element analysis with rocking dynamics to model the seismic response of complex structural geometries in a computationally-efficient manner. The modelling strategy is implemented within the open-source computational framework COMPAS and is incorporated within the broader framework of a tool being developed for the seismic collapse assessment of masonry structures. The framework of this tool is first outlined, and the utility of the new modelling approach then demonstrated through application to the seismic assessment of a three historic masonry towers in North-Eastern Italy. The importance of accounting for elastic amplification effects, as well as the influence of varying boundary conditions on the dynamic response, is also illustrated
Parents’ experiences of childhood abuse and neglect are differentially associated with behavioral and autonomic responses to their offspring
Although childhood maltreatment has been shown to compromise adaptive parental
behavior, little is known what happens in terms of physiological regulation when parents with a history of childhood maltreatment interact with their offspring. Using a
sample of 229 parents (131 women), the present study examined whether childhood
maltreatment experiences are associated with parents’ behavioral and autonomic responses while resolving conflict with their offspring. Self‐reported experienced child
maltreatment was measured using a questionnaire assessing abuse and neglect.
Parents (Mage = 52.7 years, rangeage = 26.6–88.4 years) and their offspring (Mage =
24.6 years, rangeage = 7.5–65.6 years) participated in a videotaped parent–offspring
conflict interaction task. Parental warmth, negativity, and emotional support were
coded. In addition, their pre‐ejection period and respiratory sinus arrhythmia were
measured as indicators of underlying sympathetic and parasympathetic nervous system reactivity, respectively. Findings demonstrated that experiences of abuse and
neglect were associated with behavioral and physiological responses in different
ways. Separating these two types of maltreatment in research and in clinical practice
might be important
Editorial: why and when do firms trademark? Bridging perspectives from industrial organisation, innovation and entrepreneurship
This editorial to the special issue on “Trademarks and their role in innovation, entrepreneurship and industrial organization” proposes a novel framework to understand why and when firms file trademarks. The three perspectives at the core of the special issue offer several insights on trademark motives but have not been linked f
Spatially-resolved potential measurement with ion crystals
We present a method to measure potentials over an extended region using
one-dimensional ion crystals in a radio frequency (RF) ion trap. The
equilibrium spacings of the ions within the crystal allow the determination of
the external forces acting at each point. From this the overall potential, and
also potentials due to specific trap features, are calculated. The method can
be used to probe potentials near proximal objects in real time, and can be
generalized to higher dimensions.Comment: 7 pages (double spaced), 3 figure
Long-Wavelength Instability in Surface-Tension-Driven Benard Convection
Laboratory studies reveal a deformational instability that leads to a drained
region (dry spot) in an initially flat liquid layer (with a free upper surface)
heated uniformly from below. This long-wavelength instability supplants
hexagonal convection cells as the primary instability in viscous liquid layers
that are sufficiently thin or are in microgravity. The instability occurs at a
temperature gradient 34% smaller than predicted by linear stability theory.
Numerical simulations show a drained region qualitatively similar to that seen
in the experiment.Comment: 4 pages. The RevTeX file has a macro allowing various styles. The
appropriate style is "mypprint" which is the defaul
Encapsulation of Naproxen in Lipid-Based Matrix Microspheres: Characterization and Release Kinetics
The objective of this study was to microencapsulate the anti-inflammatory drug (naproxen) to provide controlled release and minimizing or eliminating local side effect by avoiding the drug release in the upper gastrointestinal track. Naproxen was microencapsulated with lipid-like carnauba wax, hydrogenated castor oil using modified melt dispersion (modified congealable disperse phase encapsulation) technique. Effect of various formulation and process variables such as drug-lipid ratio, concentration of modifier, concentration of dispersant, stirring speed, stirring time, temperature of external phase, on evaluatory parameters such as size, entrapment efficiency, and in vitro release of naproxen were studied. The microspheres were characterized for particle size, scanning electron microscopy (SEM), FT-IR spectroscopy, drug entrapment efficiency, in vitro release studies, for in vitro release kinetics. The shape of microspheres was found to be spherical by SEM. The drug entrapment efficiency of various batches of microspheres was found to be ranging from 60 to 90 %w/w. In vitro drug release studies were carried out up to 24 h in pH 7.4 phosphate buffer showing 50-65% drug release. In vitro drug release from all the batches showed better fitting with the Korsmeyer-Peppas model, indicating the possible mechanism of drug release to be by diffusion and erosion of the lipid matrix
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