2,455 research outputs found
Remarks on the f_0(400-1200) scalar meson as the dynamically generated chiral partner of the pion
The quark-level linear sigma model is revisited, in particular concerning the
identification of the f_0(400-1200) (or \sigma(600)) scalar meson as the chiral
partner of the pion. We demonstrate the predictive power of the linear sigma
model through the pi-pi and pi-N s-wave scattering lengths, as well as several
electromagnetic, weak, and strong decays of pseudoscalar and vector mesons. The
ease with which the data for these observables are reproduced in the linear
sigma model lends credit to the necessity to include the sigma as a fundamental
q\bar{q} degree of freedom, to be contrasted with approaches like chiral
perturbation theory or the confining NJL model of Shakin and Wang.Comment: 15 pages, plain LaTeX, 3 EPS figure
Mineral Distribution In Relation To Fruit Development And Monocarpic Senescence In Anoka Soybeans
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141047/1/ajb206058.pd
A perspective on emerging automotive safety applications, derived from lessons learned through participation in the DARPA Grand Challenges
This paper reports on various aspects of the Intelligent Vehicle Systems (IVS) team's involvement in the recent 2007 DARPA Urban Challenge, wherein our platform, the autonomous “XAV-250,'' competed as one of the 11 finalists qualifying for the event. We provide a candid discussion of the hardware and software design process that led to our team's entry, along with lessons learned at this event and derived from participation in the two previous Grand Challenges. In addition, we give an overview of our vision-, radar-, and LIDAR-based perceptual sensing suite, its fusion with a military-grade inertial navigation package, and the map-based control and planning architectures used leading up to and during the event. The underlying theme of this article is to elucidate how the development of future automotive safety systems can potentially be accelerated by tackling the technological challenges of autonomous ground vehicle robotics. Of interest, we will discuss how a production manufacturing mindset imposes a unique set of constraints upon approaching the problem and how this worked for and against us, given the very compressed timeline of the contests. © 2008 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61244/1/20264_ftp.pd
Combining brain-computer interfaces and assistive technologies: state-of-the-art and challenges
In recent years, new research has brought the field of EEG-based Brain-Computer Interfacing (BCI) out of its infancy and into a phase of relative maturity through many demonstrated prototypes such as brain-controlled wheelchairs, keyboards, and computer games. With this proof-of-concept phase in the past, the time is now ripe to focus on the development of practical BCI technologies that can be brought out of the lab and into real-world applications. In particular, we focus on the prospect of improving the lives of countless disabled individuals through a combination of BCI technology with existing assistive technologies (AT). In pursuit of more practical BCIs for use outside of the lab, in this paper, we identify four application areas where disabled individuals could greatly benefit from advancements in BCI technology, namely,“Communication and Control”, “Motor Substitution”, “Entertainment”, and “Motor Recovery”. We review the current state of the art and possible future developments, while discussing the main research issues in these four areas. In particular, we expect the most progress in the development of technologies such as hybrid BCI architectures, user-machine adaptation algorithms, the exploitation of users’ mental states for BCI reliability and confidence measures, the incorporation of principles in human-computer interaction (HCI) to improve BCI usability, and the development of novel BCI technology including better EEG devices
D^+ \to K^- \p^+ \p^+ : the low-energy sector
An effective chiral lagrangian, which includes scalar
resonances, is used to describe the process D^+ \rar K^- \p^+ \p^+ at
low-energies. Our main result is a set of five -wave amplitudes, suited to
be used in analyses of production data.Comment: Talk given at SCADRON 70 - Workshop on Scalar Mesons and Related
Topics - Lisbon - February 200
The Separable Kernel of Nucleon-Nucleon Interaction in the Bethe-Salpeter Approach
The dispersion relations for nucleon-nucleon (NN) T-matrix in the framework
of Bethe-Salpeter equation for two spin one-half particle system and with
separable kernel of interaction are considered in the paper. The developed
expressions are applied for construction of the separable kernel of interaction
for S partial-waves in singlet and triplet channels. We calculate the low
energy scattering parameters and the phase shifts and also the deuteron binding
energy with the separable interaction. The approach can be easily extended to
higher partial-waves for NN-scattering and other reactions (anti N N-, pi
N-scattering).Comment: RevTex 4 style, 9 pages, 1 figur
Relativistic Contributions to Deuteron Photodisintegration in the Bethe-Salpeter Formalism
In plane wave one-body approximation the reaction of deuteron
photodisintegration is considered in the framework of the Bethe-Salpeter
formalism for two-nucleon system. Results are obtained for deuteron vertex
function, which is the solution of the homogeneous Bethe-Salpeter equation with
a multi-rank separable interaction kernel, with a given analytical form. A
comparison is presented with predictions of non-relativistic, quasipotential
approaches and the equal time approximation. It is shown that important
contributions come from the boost in the arguments of the initial state vertex
function and the boost on the relative energy in the one-particle propagator
due to recoil.Comment: 29 pages, 6 figure
Influence of batch or fed-batch growth on Staphylococcus epidermidis biofilm formation
Aims: To make a quantitative evaluation of the differences in biofilm formation by Staphylococcus epidermidis using
batch and fed-batch growth systems and to correlate this with production of the major biofilm polysaccharide,
poly-N-acetyl glucosamine (PNAG).
Methods and Results: Dry weight measurements of biofilms formed in batch and fed-batch conditions were
compared with haemagglutination titres, which measure the amount of PNAG produced. Strains grown in batch
systems developed less biofilm than when grown in fed-batch systems. A good correlation was found between the
amount of biofilm formed in fed-batch systems and the haemagglutination titres.
Conclusions: Differences in biofilm formation and PNAG production by S. epidermidis are dependent on the
availability of nutrients, with higher availability correlating with more biofilm and PNAG production.
Significance of and Impact of the Study: Comparisons of the formation of biofilms by S. epidermidis are
dependent on choosing an appropriate biofilm growth system. Comparability or disparity of conclusions among
different investigations will be strongly influenced by which mode S. epidermidis biofilms are formed.NIH - grant AI 46706.Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI) - POCTI/ESP/42688/2001, SFRH/BD/8676/2002
Utilising the left-helical conformation of L-DNA for analysing different marker types on a single universal microarray platform
L-DNA is the perfect mirror-image form of the naturally occurring d-conformation of DNA. Therefore, L-DNA duplexes have the same physical characteristics in terms of solubility, duplex stability and selectivity as D-DNA but form a left-helical double-helix. Because of its chiral difference, L-DNA does not bind to its naturally occurring D-DNA counterpart, however. We analysed some of the properties that are typical for L-DNA. For all the differences, L-DNA is chemically compatible with the D-form of DNA, so that chimeric molecules can be synthesized. We take advantage of the characteristics of L-DNA toward the establishment of a universal microarray that permits the analysis of different kinds of molecular diagnostic information in a single experiment on a single platform, in various combinations. Typical results for the measurement of transcript level variations, genotypic differences and DNA–protein interactions are presented. However, on the basis of the characteristic features of L-DNA, also other applications of this molecule type are discussed
High dillution of Staphysagria and fruit fly biotherapic preparations to manage South American fruit fly, Anastrepha fraterculus, in organic peach orchards.
The peach, Prunus persica, is an important economic crop in southern Brazil, where family farms are predominantly small. The South American fruit fly, Anastrepha fraterculus is a limiting factor to increased production in orchard crops. Increased organic production in Brazil has stimulated research to find ecological based pest management. This research was carried out in order to evaluate the efficacy of preparations at high dilution in managing A. fraterculus in organic peach orchards. Experiments were conducted under field conditions in randomized blocks during 2003/04 and 2004/05. Treatments consisted of A. fraterculus nosodes and Staphysagria homeopathic preparations, both at two high dilution levels, 3CH and 6CH (centesimal hahnemannian dilution method), applied at two spray intervals, 5 and 10 days, and a control. Fruit losses due to A. fraterculus infestation varied from 40 to 98.3%. Although there were significant differences among treatments in the first harvest of two of the three experiments there were no significant differences in the second harvest of any of the experiments. None of the homeopathic preparations reduced the incidence of infested fruit significantly below that of the water control in any of the three experiments. Further studies must combine other strategies such as bagging fruits and planting of early season cultivars. Variation on high dilution potency, dose, and frequency of application must also be considered
- …