duals of compact lie groups realized in the cuntz algebras and their actions on c algebras abstract as a first step towards a new duality theorem for compact groups we consider a representation category t g of a compact lie group g u d c whose objects are the tensor powers of the defining representation and whose arrows are the intertwiners we associate to t g in a natural way a c algebra og which can be identified with the fixed points of the cuntz algebra od under the natural action of g og carries a canonical endomorphism g and t g can be reconstructed from og g if g su d then og is simple we give conditions for an endomorphism of a unital c algebra a to determine an action of t su d on a such actions correspond to monomorphisms of osu d into a with natural intertwining properties

extensions of automorphisms and gauge symmetries we characterize the automorphisms of ac algebra open image in new window which extend to automorphisms of the crossed product open image in new window by a compact group dual the case where the inclusion open image in new window is equipped with a group of automorphisms commuting with the dual action is also treated these results are applied to the analysis of broken gauge symmetries in quantum field theory to draw conclusions on the structure of the degenerate vacua on the field algebra

noise levels and hearing thresholds in the drop forging industry a weighted equivalent continuous noise levels for hammer and press operations in a drop forging industry were determined using both tape recordings of the noise and personal noise dosimeters the results indicated average a weighted leq values of 108 db for hammer operators and 99 db for press operators comparison of hearing level statistics for 716 hammer and press operators and 293 control subjects indicated the severe hazard to hearing of impact noise exposures for mean exposure times of less than 10 years hearing levels for the press 99 db and hammer 108 db operator age groups are nearly identical and in the latter case are less than those predicted for exposure to equivalent continuous noise for long term exposures of 10 years or more the results of this study indicate that hearing losses resulting from impact noise in the drop forging industry are as great or greater than those resulting from continuous noise

development of a noise metric for assessment of exposure risk to complex noises many noise guidelines currently use a weighted equivalent sound pressure level laeq as the noise metric and the equal energy hypothesis to assess the risk of occupational noises because of the time averaging effect involved with the procedure the current guidelines may significantly underestimate the risk associated with complex noises this study develops and evaluates several new noise metrics for more accurate assessment of exposure risks to complex and impulsive noises the analytic wavelet transform was used to obtain time frequency characteristics of the noise 6 basic unique metric forms that reflect the time frequency characteristics were developed from which 14 noise metrics were derived the noise metrics were evaluated utilizing existing animal test data that were obtained by exposing 23 groups of chinchillas to respectively different types of noise correlations of the metrics with the hearing losses observed in chinchillas were compared and the most promising noise metric was identified

hearing loss from interrupted intermittent and time varying gaussian noise exposures the applicability of the equal energy hypothesis eight groups of chinchillas n 74 were exposed to various equivalent energy 100 or 106 db a sound pressure level spl noise exposure paradigms six groups received an interrupted intermittent time varying iitv gaussian noise exposure that lasted 8 h d 5 d week for 3 weeks the exposures modeled an idealized workweek at each level three different temporal patterns of gaussian iitv noise were used the 100 db a iitv exposure had a db range of 90 108 db spl while the range of the 106 db a iitv exposure was 80 115 db spl two reference groups were exposed to a uniform 100 or 106 db a spl noise 24 h d for 5 days each reference group and the three corresponding iitv groups comprised a set of equivalent energy exposures evoked potentials were used to estimate hearing thresholds and surface preparation histology quantified sensory cell populations all six groups exposed to the iitv noise showed threshold toughening effects of up to 40 db all iitv exposures produced hearing and sensory cell loss that was similar to their respective equivalent energy reference group these results indicate that for gaussian noise the equal energy hypothesis for noise induced hearing loss is an acceptable unifying principle

convergence of local charges and continuity properties of w inclusions the local generators of symmetry transformations which have recently been constructed from a quantum field theoretical version of noether s theorem are shown to converge to the global ones as the volume tends to the whole space the proof relies on the continuous volume dependence of the universal localizing maps which are associated to the local splitw inclusions

a generalized approach to random noise synthesis theory and computer simulation a generalized approach to the synthesis of gaussian and non gaussian random noises as well as purely impulsive waveforms having a preselected amplitude spectrum has been developed the basic idea behind the synthesis is to construct the amplitude time waveform from the frequency domain i e from the amplitude and phase spectra by maintaining a predetermined reference amplitude spectrum and performing certain specific manipulations of the phase spectrum within any selected band of frequencies and then applying the inverse discrete fourier transform idft peaks in the non gaussian random waveform can be constructed from the selected band of frequencies that have been phase manipulated entire families of signals can thus be produced having the same energy spectrum but statistical characteristics that vary along the continuum from gaussian skewness 0 and kurtosis 3 through non gaussian variable skewness kurtosis and crest factor to purely impulsive shock transient signals the theoretical background and the results of a series of numerical simulations will be presented which demonstrate the functional relation between various phase spectrum manipulations and the descriptors of the synthesized random noise the results show that the approach is viable and that the synthesized random waveforms can be easily tailored to simulate a variety of real world acoustic vibration signals e g high kurtosis impulsive industrial noises helicopter noises missile vibrational signals etc

applicability of the leq as a damage risk criterion an animal experiment within the european communities the leq8h is used as a damage risk criterion drc for hearing protection the use of such a drc supposes that sound exposures with equal energy imply equal risk for noise induced hearing loss nihl the aim of the present study carried out with guinea pigs was to test the applicability of the leq8h for estimating the hazard of different noises having the same spectrum and acoustic energy therefore only the temporal structure of noises was a variable continuous intermittent or impulsive and each noise had a leq8h of 92 db the results indicate the leq8h is not an accurate drc it overestimates the nihl for intermittent and short continuous noises whereas it seems to be useful for moderate intensity noises 95 db and for the impulse noise 101 db furthermore the data point out the notion of critical intensity which seems to play a determining role in the transition between metabolic and mechanical mechanisms involved in the acoustic trauma since the criti

endomorphisms of c algebras cross products and duality for compact groups on definit une nouvelle sorte de produit croise d une c algebre par des semigroupes d endomorphismes avec des proprietes reliees a la symetrie de permutation et a l existence de conjugues un groupe compact est alors defini intrinsequement par son action duale sur le produit croise cette construction donne une caracterisation des duaux de groupes compacts abstraits qui est hors d atteinte de la theorie de dualite de taunaka kein et est independante de cette theorie ceci resout le probleme de demontrer l existence d un groupe de jauge global compact en physique des particules etant seulement donnees les observables locales

compact lie groups associated with endomorphisms of c algebras on donne des conditions sur un endomorphisme d une c algebre 7b a avec unite et centre trivial en termes d operateurs d entrelacements pour des puissances de cet endomorphisme qui suffisent a determiner un groupe de lie compact g et une action d un g dual sur 7b a

conjugation in braided c categories and orthogonal quantum groups we consider braided c categories with conjugates and the notion of dimension if the braid is a birman wenzl murakami symmetry then we characterize the compact orthogonal quantum groups

on the local implementations of gauge symmetries in local quantum theory under the general assumptions of quantum field theory in terms of local algebras of field operators fulfilling the split property we prove that any two local coveriant implementations of the gauge group or in the case of a connected and simply connected lie gauge group any two choices of local current algebras relative to a pair of double cones mathcal o 1 mathcal o 2 are related by a unitary equivalence induced by a unitary in the algebra of observables localized in 2 which commutes with all fields localized in 1 where 1 is any double cone contained in the interior of mathcal o 1 and 2 any double cone containing mathcal o 2 in its interior

universal fermionization of bosons on permutative representations of the cuntz algebra o2 bosons and fermions are described by using canonical generators of cuntz algebras on any permutative representation we show a fermionization of bosons which universally holds on any permutative representation of the cuntz algebra o2 as examples we show fermionizations on the fock space and the infinite wedge

some remarks on group bundles and c dynamical systems we introduce the notion of fibred action of a group bundle on a c x algebra by using such a notion a characterization in terms of induced c bundles is given for c dynamical systems such that the relative commutant of the fixed point c algebra is minimal i e it is generated by the centre of the given c algebra and the centre of the fixed point c algebra a class of examples in the setting of the cuntz algebra is given and connections with superselection structures with nontrivial centre are discussed

morita homotopy theory of c categories abstract in this article we establish the foundations of the morita homotopy theory of c categories concretely we construct a cofibrantly generated simplicial symmetric monoidal quillen model structure denoted by m mor on the category c 1 cat of small unital c categories the weak equivalences are the morita equivalences and the cofibrations are the functors which are injective on objects as an application we obtain an elegant description of brown green rieffel s picard group in the associated homotopy category ho m mor we then prove that ho m mor is semi additive by group completing the induced abelian monoid structure at each hom set we obtain an additive category ho m mor 1 and a composite functor c 1 cat ho m mor ho m mor 1 which is characterized by two simple properties inversion of morita equivalences and preservation of all finite products finally we prove that the classical grothendieck group functor becomes co represented in ho m mor 1 by the tensor unit object

on an automorphic action of u n 1 on on abstract a simple proof of the existence of an action of the non compact lie group u n 1 on the cuntz algebra o n previously investigated by voiculescu is given a detailed study is made of the action of certain one parameter subgroups of u n 1 proving in particular cluster properties ergodicity and absence of kms states the cases n 1 and n are also discussed by somewhat different methods

energy independent factors influencing noise induced hearing loss in the chinchilla model the effects on hearing and the sensory cell population of four continuous non gaussian noise exposures each having an a weighted l eq 100 db spl were compared to the effects of an energy equivalent gaussian noise the non gaussian noise conditions were characterized by the statistical metric kurtosis beta computed on the unfiltered beta t and the filtered beta f time domain signals the chinchilla n 58 was used as the animal model hearing thresholds were estimated using auditory evoked potentials aep recorded from the inferior colliculus and sensory cell populations were obtained from surface preparation histology despite equivalent exposure energies the four non gaussian conditions produced considerably greater hearing and sensory cell loss than did the gaussian condition the magnitude of this excess trauma produced by the non gaussian noise was dependent on the frequency content but not on the average energy content of the impacts which gave the noise its non gaussian character these results indicate that beta t is an appropriate index of the increased hazard of exposure to non gaussian noises and that beta f may be useful in the prediction of the place specific additional outer hair cell loss produced by non gaussian exposures the results also suggest that energy based metrics while necessary for the prediction of noise induced hearing loss are not sufficient

density functional approach to quantum lattice systems for quantum lattice systems we consider the problem of characterizing the set of single particle densities which come from the ground state eigenspace of somen particle hamiltonian of the form h 0 sum nolimits i 1 n v x i whereh0 is a fixed bounded operator representing the kinetic and interaction energies we show that the conditions on are that it be strictly positive properly normalized and consistent with the pauli principle our results are valid for both finite and infinite lattices and for either bosons or fermions the coulomb interaction may be included inh0 if the lattice dimension is 2 we also characterize those single particle densities which come from the gibbs states of such hamiltonians at finite temperature in addition to the conditions stated above must satisfy a finite entropy condition

the application of frequency and time domain kurtosis to the assessment of hazardous noise exposures five computer synthesized broadband noises each having the same average spectrum and the same unweighted leq of 100 db spl but very different temporal structures were used to produce hearing loss in chinchillas despite the same exposure energies and spectra each noise exposure produced a different magnitude and frequency distribution of hearing loss and sensory cell loss the results indicate that the statistical properties of a signal are important in the determination of hearing loss when the audiometric and histological results are compared to a metric based upon kurtosis measured in the time and the frequency domain for each exposure there is a clear indication that these statistical metrics are good predictors of the relative magnitude and frequency distribution of the acoustic trauma

coarse grained spin density functional theory infinite volume limit via the hyperfinite coarse grained spin density functional theory sdft is a version of sdft which works with number spin densities specified to a limited resolution averages over cells of a regular spatial partition and external potentials constant on the cells this coarse grained setting facilitates a rigorous investigation of the mathematical foundations which goes well beyond what is currently possible in the conventional formulation problems of existence uniqueness and regularity of representing potentials in the coarse grained sdft setting are here studied using techniques of robinsonian nonstandard analysis every density which is nowhere spin saturated is v representable and the set of representing potentials is the functional derivative in an appropriate generalized sense of the lieb internal energy functional quasi continuity and closure properties of the set valued representing potentials map are also established the extent of possible non uniqueness is similar to that found in non rigorous studies

quantum spin chains with quantum group symmetry we consider actions of quantum groups on lattice spin systems we show that if an action of a quantum group respects the local structure of a lattice system it has to be an ordinary group even allowing weakly delocalized quasi local tails of the action we find that there are no actions of a properly quantum group commuting with lattice translations the non locality arises from the ordering of factors in the quantum groupc algebra and can be made one sided thus allowing semi local actions on a half chain under such actions localized quantum group invariant elements remain localized hence the notion of interactions invariant under the quantum group and also under translations recently studied by many authors makes sense even though there is no global action of the quantum group we consider a class of such quantum group invariant interactions with the property that there is a unique translation invariant ground state under weak locality assumptions its gns representation carries no unitary representation of the quantum group

hohenberg kohn theorem and non v representable densities abstract in the density functional formalism of hohenberg and kohn1 the variation is only allowed over the one particle densities which are pure state v representable ps v representable levy2 and lieb3 proved that not every ensemble v representable e v representable density is ps v representable since we show that the hohenberg kohn formalism can be extended to a variation over e v representable densities for degenerated ground states levy s and lieb s result is not a counterexample to the universality of the hohenberg kohn theorem the question whether every n representable density is e v representable has remained open so far presenting examples of non e v representable densities we answer this question in the negative thus the value of levy s functional4 for the calculation of ground state energies is obvious since this functional only requires the n representability of the densities therefore we transfer two approaches for the calculation of excited state energies into the framework of levy s formalism

hearing loss in the chinchilla from impact and continuous noise exposure the relative hazard posed to the peripheral auditory system by impact impulse and continuous noise of the same power spectrum was determined impact noise was generated by striking a nail with a hammer and was digitally recorded the acoustical power spectrum of the impact was determined and pink noise was filtered to produce a continuous noise stimulus with the same acoustic power spectrum pre exposure auditory evoked response aer thresholds were obtained at 1 2 4 and 8 khz on 16 adult chinchillas the pool of animals was divided into two equal groups based upon pre exposure aer thresholds one group was exposed to impact noise and the other group to the filtered pink noise exposures were 4 h day for 5 days thirty days following the exposure auditory evoked response thresholds were remeasured changes in auditory sensitivity were determined by subtracting the pre exposure thresholds from the post exposure thresholds hearing threshold shifts of the impact noise group were significantly greater

beyond v representability local one body hamiltonians for arbitrary densities the v representability problem arising in density functional theory is this for an particle system of interacting identical particles can every one particle density of finite intrinsic energy be realized as a ground state density upon modifying the hamiltonian by addition of an appropriate external one body potential v the answer is known to be no we show that the answer is yes if the inter particle interaction is bounded and allowed modifications are broadened from one body potentials to local one body operators the required operator is obtained from a non standard potential in the sense of non standard analysis which is a simple function defined on a regular grid of infinitesimal finesse at a vague conceptual level therefore the result is not far from universal v representability

the kurtosis metric as an adjunct to energy in the prediction of trauma from continuous nongaussian noise exposures data from an earlier study hamernik et al 2003 j acoust soc am 114 386 395 were consistent in showing that for equivalent energy leq 100 db a and spectra exposure to a continuous nongaussian nong noise could produce substantially greater hearing and sensory cell loss in the chinchilla model than a gaussian g noise exposure and that the statistical metric kurtosis computed on the amplitude distribution of the noise could order the extent of the trauma this paper extends these results to leq 90 and 110 db a and to nong noises that are generated using broadband noise bursts and band limited impacts within a continuous g background noise data from nine new experimental groups with 11 or 12 chinchillas group is presented evoked response audiometry established hearing thresholds and surface preparation histology quantified sensory cell loss at the lowest level leq 90 db a there were no differences in the trauma produced by g and nong exposures for leq 90 db a nong exposures produced increased trauma relative to equivalent g exposures removing energy from the impacts by limiting their bandwidth reduced trauma the use of noise bursts to produce the nong noise instead of impacts also reduced the amount of trauma

a new duality theory for compact groups the tannaka krein duality theory characterizes the category g of finite dimensional continuous unitary representations of a compact group as a subcategory of the category of hilbert spaces we prove a more powerful result characterizing g as an abstract category every strict symmetric monoidalc category with conjugates which has subobjects and direct sums and for which thec algebra of endomorphisms of the monoidal unit reduces to the complex numbers is isomorphic to a category g for a compact groupg unique up to isomorphism

continuous fields of c algebras arising from extensions of tensor c categories abstract the notion of extension of a given c category c by a c algebra a is introduced in the commutative case a c the objects of the extension category are interpreted as fiber bundles over of objects belonging to the initial category it is shown that the doplicher roberts algebra dr algebra in the following associated to an object in the extension of a strict tensor c category is a continuous field of dr algebras coming from the initial one in the case of the category of the hermitian vector bundles over the general result implies that the dr algebra of a vector bundle is a continuous field of cuntz algebras some applications to pimsner c algebras are given

correspondences of ribbon categories much of algebra and representation theory can be formulated in the general framework of tensor categories the aim of this paper is to further develop this theory for braided tensor categories several results are established that do not have a substantial counterpart for symmetric tensor categories in particular we exhibit various equivalences involving categories of modules over algebras in ribbon categories finally we establish a correspondence of ribbon categories that can be applied to and is in fact motivated by the coset construction in conformal quantum field theory

a remark on compact automorphism groups of c algebras abstract a c system over a compact group whose fixed point algebra has trivial centre and a relative commutant coinciding with the centre of the full algebra is obtained canonically by inducing up from a c system over a closed subgroup with the same fixed point algebra but which now has trivial relative commutant