Morphology of sesamoid bones in keyboard musicians

Background: The sesamoid bones are small, usually oval bone structures often found in joints and under the tendons. Although their precise function is not fully understood, it is agreed upon that they protect the joints and make movements faster and less energy consuming. Sesamoid bones are found in hands, especially around first, second and fifth metacarpophalangeal joint and the interphalangeal joint of the thumb. Materials and methods: This study compares a group of 32 young musicians to 30 non-musicians of similar age and posture. The hands of the subjects were examined by ultrasound imaging for the presence of sesamoid bones. The results were noted and observed sesamoids were measured. Results: The results seem to prove that although there are no difference in the amount or the location of the sesamoid bones between the musicians and the non-musicians, there is statistically significant tendency for the musicians to have bigger sum of the sesamoid’s volume per hand (Fisher’s test p-value = 0.034 < 0.05). Conclusions: There was also observed an unusually shaped “Bactrian” sesamoid bone at the interphalangeal joint of the thumb in 8 cases in the musicians’ group and 1 case in the control group. All participants with the aforementioned structure were female

Importance of reaction volume in hadronic collisions: Canonical enhancement

We study the canonical flavor enhancement arising from exact conservation of strangeness, and charm flavor. Both the theoretical motivation, and the practical consequences are explored. We argue using qualitative theoretical arguments and quantitative evaluation, that this proposal to reevaluate strangeness signature of quark--gluon plasma is not able to explain the majority of available experimental results.Comment: 14 pages including 6 figures, submitted to Journal of Physics G Presented at: Strange Quark Matter, September 2001, Frankfur

Strangeness Production in Nuclear Matter and Expansion Dynamics

Thermodynamical properties of hot and dense nuclear matter are analyzed and compared for different equation of state (EoS). It is argued that the softest point of the equation of state and the strangeness separation on the phase boundary can manifest themselves in observables. The influence of the EoS and the order of the phase transition on the expansion dynamics of nuclear matter and strangeness excitation function is analyzed. It is shown that bulk properties of strangeness production in A-A collisions depend only weakly on the particular form of the EoS. The predictions of different models are related with experimental data on strangeness production.Comment: 38 page

Strangeness and Quark Gluon Plasma

A brief summary of strangeness mile stones is followed by a chemical non-equilibrium statistical hadronization analysis of strangeness results at SPS and RHIC. Strange particle production in AA interactions at \sqrt{s_{NN}}\ge 8.6 GeV can be understood consistently as originating from the deconfined quark--gluon plasma in a sudden hadronization process. Onset of QGP formation as function of energy is placed in the beam energy interval 10--30A GeV/c. Strangeness anomalies at LHC are described.Comment: 30 pages including numerouse figures, tables. Opening Lecture: Strangeness and Quark Gluon Plasma -- what has been learned so far and where do we go at SQM2003, North Carolina, March 2003, submitted to J. Phys.

Baryon Stopping and Charged Particle Distributions in Central Pb+Pb Collisions at 158 GeV per Nucleon

Net proton and negative hadron spectra for central \PbPb collisions at 158 GeV per nucleon at the CERN SPS were measured and compared to spectra from lighter systems. Net baryon distributions were derived from those of net protons, utilizing model calculations of isospin contributions as well as data and model calculations of strange baryon distributions. Stopping (rapidity shift with respect to the beam) and mean transverse momentum \meanpt of net baryons increase with system size. The rapidity density of negative hadrons scales with the number of participant nucleons for nuclear collisions, whereas their \meanpt is independent of system size. The \meanpt dependence upon particle mass and system size is consistent with larger transverse flow velocity at midrapidity for \PbPb compared to \SS central collisions.Comment: This version accepted for publication in PRL. 4 pages, 3 figures. Typos corrected, some paragraphs expanded in response to referee comments, to better explain details of analysi

Measurement of the diffractive structure function in deep inelastic scattering at HERA

This paper presents an analysis of the inclusive properties of diffractive deep inelastic scattering events produced in $ep$ interactions at HERA. The events are characterised by a rapidity gap between the outgoing proton system and the remaining hadronic system. Inclusive distributions are presented and compared with Monte Carlo models for diffractive processes. The data are consistent with models where the pomeron structure function has a hard and a soft contribution. The diffractive structure function is measured as a function of \xpom, the momentum fraction lost by the proton, of $\beta$, the momentum fraction of the struck quark with respect to \xpom, and of $Q^2$. The \xpom dependence is consistent with the form \xpoma where $a~=~1.30~\pm~0.08~(stat)~^{+~0.08}_{-~0.14}~(sys)$ in all bins of $\beta$ and $Q^2$. In the measured $Q^2$ range, the diffractive structure function approximately scales with $Q^2$ at fixed $\beta$. In an Ingelman-Schlein type model, where commonly used pomeron flux factor normalisations are assumed, it is found that the quarks within the pomeron do not saturate the momentum sum rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil

Independent Component Analysis-motivated Approach to Classificatory Decomposition of Cortical Evoked Potentials

BACKGROUND: Independent Component Analysis (ICA) proves to be useful in the analysis of neural activity, as it allows for identification of distinct sources of activity. Applied to measurements registered in a controlled setting and under exposure to an external stimulus, it can facilitate analysis of the impact of the stimulus on those sources. The link between the stimulus and a given source can be verified by a classifier that is able to "predict" the condition a given signal was registered under, solely based on the components. However, the ICA's assumption about statistical independence of sources is often unrealistic and turns out to be insufficient to build an accurate classifier. Therefore, we propose to utilize a novel method, based on hybridization of ICA, multi-objective evolutionary algorithms (MOEA), and rough sets (RS), that attempts to improve the effectiveness of signal decomposition techniques by providing them with "classification-awareness." RESULTS: The preliminary results described here are very promising and further investigation of other MOEAs and/or RS-based classification accuracy measures should be pursued. Even a quick visual analysis of those results can provide an interesting insight into the problem of neural activity analysis. CONCLUSION: We present a methodology of classificatory decomposition of signals. One of the main advantages of our approach is the fact that rather than solely relying on often unrealistic assumptions about statistical independence of sources, components are generated in the light of a underlying classification problem itself

Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde