2,672 research outputs found
Characteristics of Staphylococcus aureus infections to consider in designing an effective vaccine.
_Staphylococcus aureus_ is a very versatile and adaptable microorganism. It can potentially infect virtually any host tissue. Given the appropriate conditions it can become a life-threatening pathogen, or a commensal colonizer of the nose. Extensive antibiotic use for infection control facilitated the rise of antibiotic resistance, stressing the need for alternate forms of control. Vaccine efforts in other pathogens have proved successful, but so far _S. aureus_ candidate vaccines have not been as effective. Here we review _S. aureus_ factors involved in pathogenesis that could help develop a successful vaccine, like host nasal colonization and immune evasion factors. An effective multicomponent vaccine could incorporate antigenic fragments from several _S. aureus_ proteins, preferably involved in colonization, immune evasion and/or toxicity
Relevance of social capital in understanding and negotiating conflict around water management in a micro basin in the Andes region
Antiferromagnetism at the YBa2Cu3O7 / La2/3Ca1/3MnO3 interface
The magnetic properties of a series of YBa2Cu3O7-x/La2/3Ca1/3MnO3
(YBCO/LC1/3MO) superlattices grown by dc sputtering at high oxygen pressures
(3.5 mbar) show the expected ferromagnetic behaviour. However, field cooled
hysteresis loops at low temperature show the unexpected existence of exchange
bias, effect associated with the existence of ferromagnetic/antiferromagnetic
(F/AF) interfaces. The blocking temperature (TB) is found thickness dependent
and the exchange bias field (HEB) is found inversely proportional to the FM
layer thickness, as expected. The presence of an AF material is probably
associated to interface disorder and Mn valence shift towards Mn4+.Comment: 12 pages, 2 figures, 1 table, submitted to Applied Physics Letter
Magnons in Ferromagnetic Metallic Manganites
Ferromagnetic (FM) manganites, a group of likely half-metallic oxides, are of
special interest not only because they are a testing ground of the classical
doubleexchange interaction mechanism for the colossal magnetoresistance, but
also because they exhibit an extraordinary arena of emergent phenomena. These
emergent phenomena are related to the complexity associated with strong
interplay between charge, spin, orbital, and lattice. In this review, we focus
on the use of inelastic neutron scattering to study the spin dynamics, mainly
the magnon excitations in this class of FM metallic materials. In particular,
we discussed the unusual magnon softening and damping near the Brillouin zone
boundary in relatively narrow band compounds with strong Jahn-Teller lattice
distortion and charge/orbital correlations. The anomalous behaviors of magnons
in these compounds indicate the likelihood of cooperative excitations involving
spin, lattice, as well as orbital degrees of freedom.Comment: published in J. Phys.: Cond. Matt. 20 figure
A KINEMATIC ANALYSIS OF THE NAERYO-CHAGI TECHNIQUE IN TAEKWONDO
The purpose of this study was to investigate the influence of selected kinematic parameters on the performance of the naeryo-chagi technique in taekwondo. Performance was quantified by the vertical velocity of the ankle at initial target contact (VIMP). METHOD: A sample of 19 competitive taekwondo athletes (17 males and 2 females) aged from 17 to 30 years (mean age = 19 ± 4), who were able to accomplish a correct naeryo-chagi technique, participated in this study. After warm up, participants were asked to perform several series of five naeryo-chagi kicks with their front leg at a kicking pad which was mounted on a frame at chin height. For data acquisition a motion tracking system comprising eight infrared cameras and a force plate were used. Only that series, which included the trial with the highest ankle velocity at initial target contact, was further processed. RESULTS: Significant differences between the best and worst performed kick of each athlete (p = 0.025) were found for the extension of the hip joint during the pull down phase (EHIP). No significant differences were found for the maximum ankle velocity during the strike out phase (AVSO; p = 0.28). Considering the best trials of each athlete only, Pearson correlation between EHIP and VIMP was significant (r = 0.542; p = 0.017), that between AVSO and VIMP was not (r = 0.354, p = 0.137). CONCLUSION: The magnitude of change of the hip flexion angle during the pull down movement seems to be an important factor for performing a kick featuring high velocity at initial target contact
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