The Active Traveling Wave in the Cochlea

A sound stimulus entering the inner ear excites a deformation of the basilar membrane which travels along the cochlea towards the apex. It is well established that this wave-like disturbance is amplified by an active system. Recently, it has been proposed that the active system consists of a set of self-tuned critical oscillators which automatically operate at an oscillatory instability. Here, we show how the concepts of a traveling wave and of self-tuned critical oscillators can be combined to describe the nonlinear wave in the cochlea.Comment: 5 pages, 2 figure

Analysis of electroencephalograms in Alzheimer's disease patients with multiscale entropy

The aim of this study was to analyse the electroencephalogram (EEG) background activity of Alzheimer’s disease (AD) patients using the Multiscale Entropy (MSE). The MSE is a recently developed method that quantifies the regularity of a signal on different time scales. These time scales are inspected by means of several coarse-grained sequences formed from the analysed signals. We recorded the EEGs from 19 scalp electrodes in 11 AD patients and 11 age-matched controls and estimated the MSE profile for each epoch of the EEG recordings. The shape of the MSE profiles reveals the EEG complexity, and it suggests that the EEG contains information in deeper scales than the smallest one. Moreover, the results showed that the EEG background activity is less complex in AD patients than control subjects. We found significant difference

Hadron Spectroscopy with COMPASS at CERN

The aim of the COMPASS hadron programme is to study the light-quark hadron spectrum, and in particular, to search for evidence of hybrids and glueballs. COMPASS is a fixed-target experiment at the CERN SPS and features a two-stage spectrometer with high momentum resolution, large acceptance, particle identification and calorimetry. A short pilot run in 2004 resulted in the observation of a spin-exotic state with $J^{PC} = 1^{-+}$ consistent with the debated $\pi1(1600)$. In addition, Coulomb production at low momentum transfer data provide a test of Chiral Perturbation Theory. During 2008 and 2009, a world leading data set was collected with hadron beam which is currently being analysed. The large statistics allows for a thorough decomposition of the data into partial waves. The COMPASS hadron data span over a broad range of channels and shed light on several different aspects of QCD.Comment: 4 pages, 5 figure

Production, Collection and Utilization of Very Long-Lived Heavy Charged Leptons

If a fourth generation of leptons exists, both the neutrino and its charged partner must be heavier than 45 GeV. We suppose that the neutrino is the heavier of the two, and that a global or discrete symmetry prohibits intergenerational mixing. In that case, non-renormalizable Planck scale interactions will induce a very small mixing; dimension five interactions will lead to a lifetime for the heavy charged lepton of $O(1-100)$ years. Production of such particles is discussed, and it is shown that a few thousands can be produced and collected at a linear collider. The possible uses of these heavy leptons is also briefly discussed.Comment: 9 pages Late

Isoscalar-isovector mass splittings in excited mesons

Mass splittings between the isovector and isoscalar members of meson nonets arise in part from hadronic loop diagrams which violate the Okubo-Zweig-Iizuka rule. Using a model for these loop processes which works qualitatively well in the established nonets, I tabulate predictions for the splittings and associated isoscalar mixing angles in the remaining nonets below about 2.5 GeV, and explain some of their systematic features. The results for excited vector mesons compare favorably with experiment.Comment: 8 RevTeX pages, including 1 LaTeX figure. CMU-HEP93-23/DOE-ER-40682-4

Exploring the QCD landscape with high-energy nuclear collisions

Quantum chromodynamics (QCD) phase diagram is usually plotted as temperature (T) versus the chemical potential associated with the conserved baryon number (\mu_{B}). Two fundamental properties of QCD, related to confinement and chiral symmetry, allows for two corresponding phase transitions when T and \mu_{B} are varied. Theoretically the phase diagram is explored through non-perturbative QCD calculations on lattice. The energy scale for the phase diagram (\Lambda_{QCD} ~ 200 MeV) is such that it can be explored experimentally by colliding nuclei at varying beam energies in the laboratory. In this paper we review some aspects of the QCD phase structure as explored through the experimental studies using high energy nuclear collisions. Specifically, we discuss three observations related to the formation of a strongly coupled plasma of quarks and gluons in the collisions, experimental search for the QCD critical point on the phase diagram and freeze-out properties of the hadronic phase.Comment: Submitted to the New Journal of Physics focus issue "Strongly Correlated Quantum Fluids: From Ultracold Quantum Gases to QCD Plasmas

The Effect of Consummatory Stimuli on Brain Stimulation Reinforcement: Further Differentiation of Killing and Feeding Mechanisms in the Posterior Hypothalamus of Rats

Traditionally, killing or aggressive behavior has been viewed as an operant performed to gain reinforcement such as food. There is, however, increasing evidence indicating that killing is reinforcing in itself. Myer and White (1965) and Van Herrel (1970) have shown that natural killing behavior can be used to reinforce the learning of discrimination. Roberts and Kiess (1964) implanted electrodes in the anterior hypothalamus of natural non-killing rats and elicited killing behavior. They showed that this electrically elicited killing could also be used to reinforce the learning of discrimination. Thompson (1963,1964) demonstrated that both Siamese fighting fish and fighting game cocks would perform an operant to see a nonspecific and give their species-typical aggressive display. Tellegren et. al. (1969) showed that fighting mice will choose the arm of a T-maze which contained a mouse which they could attack. The relationship between feeding and killing has been thought to be a very close one. However, there has been a controversy in the literature as to whether killing is controlled by feeding and therefore a sub-system of a feeding mechanism or whether it’s an independent system in itself. Karli (1956) showed that natural killers would not eat the prey they had killed and natural non-killers would starve to death rather than kill. Von Hemel and Meyer (1970) and DeSisto and Huston (1970) found that natural killing rats would kill up to 30 mice and frogs without ever having ~he opportunity to eat them. Whalen and Fehr (1964) and Paul et. a1. (1971) have shown that cyclic food deprivation could increase the frequency of killing in a group of rats. Heimstra (1965) was not able to induce killing with cyclic food deprivation. Roberts and Kiess (1964) showed that hungry cats, from whom they were electrically elicited killing, would immediately leave a bowl of food to kill a rat when electrical stimulation was turned on. Hutchinson and Renfrew (1966) were able to elicit both feeding and killing from the same electrode although elicitation of killing was always at a higher current level. King and Hoebel (1968), DeSisto and Huston (1971) never observed feeding in stimuli-bound killers during stimulation and never observed killing in stimuli us-bound feeders. Karli and Vergnes (1964) showed that when both feeding and killing were abolished by rostral to caudal bilateral lesions within the hypothalamus, killing recovered before feeding in all cases. Thus killing took place with no feeding. The focus of the present set of experiments was to further clarify the relationship between killing and feeding mechanisms in the hypothalamus. Male Long-Evans hooded rats were implanted with bipolar electrodes aimed at the posterior lateral hypothalamus. They were tested for S-bound behaviors and S-bound feeders and killers were used in the experiments. The subjects were then trained to bar press. They received stimulation for as long as the bar was held down. Then either food, live frog or no goal object was placed above the bar and the rat was allowed to bar press and engage in an S-bound behavior simultaneously. The average bar press duration was recorded for each rat. The rats were run both food satiated and food deprived. A preference test was then run. Two bars were mounted at the end of the box and either no goal object, food, or frog were placed above each bar in various combinations. The rat was placed in the box and allowed to press at either bar. The results were quite clear. The live frog and thus an opportunity to kill elicited longer durations of bar press for the S-bound killers than did the food or no goal object. For the S-bound feeders, the food elicited the longer duration. The results were unaffected by food deprivation. Thus, the effects of feeding and willing were differentiated in this experiment. The one S-bound killer run in the preference test showed a clear preference for the bar that had the frog over it. These findings suggest that killing is in fact a mechanism in itself and one that is distinct from the feeding mechanism

Strangeness Content in the Nucleon

I review recent studies of strangeness content in the nucleon pertaining to the flavor-singlet $g_A^0$, the $\bar{s}s$ matrix element and the strangeness electric and magnetic form factors $G_E^s(q^2)$ and $G_M^s(q^2)$, based on lattice QCD calculations. I shall also discuss the relevance of incorporating the strangeness content in nuclei in regard to strange baryon-antibaryon productions from proton-nucleus and nucleus-nucleus collisions at SPS and RHIC energies.Comment: 11 pages, 4 figures, Invited talk at V Int. Conf. on Strangeness in Quark Matter, Berkeley, CA, July 20--25, 200

History of exotic Meson (4-quark) and Baryon (5-quark) States

I briefly review the history of exotic meson (4-quark) and baryon (5-quark) states, which is rooted in the formalism of Regge pole and duality. There are robust model-independent predictions for the exchange of 4-quark (Baryonium) Regge trajectories in several processes, which are strongly supported by experiment. On the other hand the predictions for the spectroscopy of 4-quark resonances are based on specific QCD inspired models, with some experimental support. The corresponding predictions for the recently discovered exotic baryon (Pentaquark) state are briefly discussed.Comment: 14 pages Latex including 4 eps figures, final version to appear as a topical review in J. Phys.

Researching the home using architectural and social science methods

This article explores the possibilities of using innovative, interdisciplinary methods for understanding home-making. Drawing on a study of Claremont Court (1959–1962), a post-war social housing scheme designed by Sir Basil Spence in Edinburgh, we discuss the methodological potentials of combining architectural and social science methods to study the home. Claremont Court was built in the post-war era as part of Scotland’s social housing drive. It was designed following the principles of ‘cross-class’ living in order to foster a sense of community. In subsequent years, inhabitants of the court have adapted their dwellings in numerous ways and the population of the court has changed dramatically. But, while meanings of home and understandings of the division between public and private have been reconfigured, the spatial layouts of the dwellings continue to shape residents’ sense of home. To explore how residents make home at Claremont Court, we use ‘facet methodology’, which opens up new ways of thinking about the research process through a ‘playful’ approach to epistemology. In doing so, we develop an innovative approach which combines architectural methods (including survey drawings and visual mappings of both dwellings and communal areas) with social science methods (including ‘traditional’ interviews and walk-along interviews). To conclude, we discuss the possibility of widening the scope of qualitative research by bringing architectural and social science methods into dialogue through visual methods, in order to attend to spatial and material aspects of the home. We argue that our novel cross-disciplinary approach broadens understandings of home, by bringing attention to the unspoken dimensions of physical space, embodied elements of home and what people said about their homes, all of which are central to home-making