the fine structure of the recovering auditory detection threshold detection thresholds were gathered for a 2 khz gaussian shaped probe standard deviation 0 5 ms centered at intervals of as little as half a millisecond over 0 30 ms following a 200 ms 97 db spl 2 khz tone surprisingly there were small sudden rises and falls superimposed on each subject s generally smooth recovery even more obvious were nonmonotonicities in the standard deviation of the cumulative normal fitted to each threshold s psychometric function

a recursive formula for characters of simple lie algebras abstract in 1964 antoine and speiser published succinct and elegant formulae for the characters of the irreducible highest weight modules for the lie algebras a2 and b2 the result for a2 may have been known as early as 1957 these can be derived from a recursive formula for characters valid for all simple complex kac moody lie algebras for which the weyl kac character formula holds

effects of masker duration in pure tone forward masking the masking of one tone by a preceding tone forward masking was studied as a function of the duration of the masker in general it was found that forward masking increased with increasing masker duration for the range of durations used 35 to 500 msec the functions relating masked probe threshold in decibels to the logarithm of masker duration were well described by straight lines the rate of growth of forward masking as a function of masker duration was greatest for relatively high masker levels and frequencies

effects of peripheral nonlinearity on psychometric functions for forward masked tones psychometric functions pfs for forward masked tones were obtained for conditions in which signal level was varied to estimate threshold at several masker levels variable signal condition and in which masker level was varied to estimate threshold at several signal levels variable masker condition the changes in pf slope across combinations of masker frequency masker level and signal delay were explored in three experiments in experiment 1 a 2 khz 10 ms tone was masked by a 50 70 or 90 db spl 20 ms on frequency forward masker with signal delays of 2 20 or 40 ms in a variable signal condition pf slopes decreased in conditions where signal threshold was high in experiments 2 and 3 the signal was a 4 khz 10 ms tone and the masker was either a 4 or 2 4 khz 200 ms tone in experiment 2 on frequency maskers were presented at 30 to 90 db spl in 10 db steps and off frequency maskers were presented at 60 to 90 db spl in 10 db steps with signal delays of 0 10 or 30 ms in a variable signal condition pf slopes decreased as signal level increased and this trend was similar for on and off frequency maskers in experiment 3 variable masker conditions with on and off frequency maskers and 0 ms signal delay were presented in general the results were consistent with the hypothesis that peripheral nonlinearity is reflected in the pf slopes the data also indicate that masker level plays a role independent of signal level an effect that could be accounted for by assuming greater internal noise at higher stimulus levels

some global dynamical properties of the kuramoto sivashinsky equations nonlinear stability and attractors abstract the kuramoto sivashinsky equations model pattern formations on unstable flame fronts and thin hydrodynamic films they are characterized by the coexistence of coherent spatial structures with temporal chaos we investigate some global dynamical properties including nonlinear stability we demonstrate their low modal behavior in terms of determining modes and that the fractal dimension of all attractors is bounded by a universal constant times l 13 8 where l is a dimensionless pattern cell size in the one dimensional case such equations are indeed a paradigm of low dimensional behavior for infinite dimensional systems

finite fractal dimensions of random attractors for stochastic fitzhugh nagumo system with multiplicative white noise abstract in this paper we consider the asymptotic behavior of solutions for stochastic non autonomous fitzhugh nagumo system with multiplicative white noise first we prove the existence of random attractor of the random dynamical system generated by the solutions of considered system then we present some conditions for estimating an upper bound of the fractal dimension of a random invariant set of a random dynamical system on a separable banach space and apply these conditions to prove the finiteness of fractal dimension of random attractor

dependence of post masking on masker duration and its relation to temporal effects in loudness temporal masking of tones by noise was investigated using a post forward masking paradigm the masker level and duration were varied for every masker level employed the rate of decay of masking was found to depend on the duration of the masker specific loudness values were computed from the forward masking functions and an electronic device which simulates these loudness functions is presented in the simulation a series of integrators or a single integration with one long time constant was utilized the effect of the proposed integrators on loudness meters is discussed

pullback attractors for the non autonomous fitzhugh nagumo system on unbounded domains abstract the existence of a pullback attractor is established for the singularly perturbed fitzhugh nagumo system defined on the entire space r n when external terms are unbounded in a phase space the pullback asymptotic compactness of the system is proved by using uniform a priori estimates for far field values of solutions although the limiting system has no global attractor we show that the pullback attractors for the perturbed system with bounded external terms are uniformly bounded and hence do not blow up as a small parameter approaches zero

inertial manifolds the non self adjoint case abstract in contrast with the existing theories of inertial manifolds which are based on the self adjoint assumption of the principal differential operator in this paper we show that for general dissipative evolutionary systems described by semilinear parabolic equations with principal differential operator being sectorial and having compact resolvent there exists an inertial manifold provided that certain gap conditions hold we also show that by using an elliptic regularization this theory can be extended to a class of kdv equations where the principal differential operator is not sectorial

inertial manifolds for nonlinear evolutionary equations abstract in this paper we introduce the concept of an inertial manifold for nonlinear evolutionary equations in particular for ordinary and partial differential equations these manifolds which are finite dimensional invariant lipschitz manifolds seem to be an appropriate tool for the study of questions related to the long time behavior of solutions of the evolutionary equations the inertial manifolds contain the global attractor they attract exponentially all solutions and they are stable with respect to perturbations furthermore in the infinite dimensional case they allow for the reduction of the dynamics to a finite dimensional ordinary differential equation

abelian ideals of borel subalgebras and affine weyl groups abstract this paper is devoted to a detailed study of certain remarkable posets which form a natural partition of all abelian ideals of a borel subalgebra our main result is a nice uniform formula for the dimension of maximal ideals in these posets we also obtain results on ad nilpotent ideals which complete the analysis started in j algebra 225 2000 130 258 2002 112

spherical orbits and abelian ideals let g be a connected reductive complex algebraic group with lie algebra lie g g let b be a borel subgroup of g with unipotent radical bu we denote the lie algebra of b and bu by b and bu respectively the group b acts on any ideal of b by means of the adjoint representation after a preliminary section we study a relationship between spherical nilpotent orbits and abelian ideals a of b using the structure theory for these orbits from 10 the principal result of this section is that for an abelian ideal a of b any nilpotent orbit meeting a is a spherical g variety see theorem 2 3 as a consequence of this we obtain a short conceptual proof of a finiteness theorem from 14 namely for a parabolic subgroup p of g and an abelian ideal a of p lie p in the nilpotent radical pu lie pu the group p operates on a with finitely many orbits the proof of this fact in 14 involved long and tedious case by case considerations we also prove a partial converse to the result just mentioned following 4 we say that an ideal of b is ad nilpotent whenever it consists of nilpotent elements in case g is simply laced we show that an ad nilpotent ideal c of b is abelian provided any nilpotent orbit meeting c is spherical see proposition 2 7 in section 3 we consider some properties of ad nilpotent ideals of b in theorem 3 2 we give a description of the normaliser of such ideals this applies in particular to abelian ideals of b a remarkable theorem of doi 10 1006 aima 2000 1959 available online at http www idealibrary com on

detection of the break in interaural correlation is affected by interaural delay aging and center frequency this study investigated whether interaural integration is affected by introducing an interaural delay in experiment 1 both younger adults with normal hearing and older adults in the early stages of presbycusis were able to detect a transient break in interaural correlation bic in the temporal middle of interaurally correlated wideband noises however their duration thresholds for detecting the bic became larger with increasing interaural time difference itd from 0 to 6 ms and the threshold increase for older participants was larger than that for younger participants in experiment 2 to investigate whether the effect of changing itd on the bic detection is frequency dependent 1 3 octave narrowband noises with various center frequencies were used as stimuli results show that the duration threshold for detecting the bic was higher for high frequency noises than for low frequency noises also with increasing itd from 0 to 4 ms the threshold increase was larger for high frequency noises than for low frequency noises the results suggest that there are age and frequency related temporal declines in maintaining fine structure signals for interaural integration these declines may affect the recognition of sound sources in reverberant environments

temporal order discrimination of tonal sequences by younger and older adults the role of duration and rate the effect of tone duration and presentation rate on the discrimination of the temporal order of the middle two tones of a four tone sequence was investigated in young normal hearing ynh and older hearing impaired ohi listeners the frequencies and presentation level of the tone sequences were selected to minimize the effect of hearing loss on the performance of the ohi listeners tone durations varied from 20to400ms and presentation rates from 2 5to25tones s two experiments were conducted with anisochronous nonuniform duration and rate across entire sequence and isochronous uniform rate and duration sequences respectively for the ynh listeners performance for both isochronous and anisochronous sequences was determined primarily by presentation rate such that performance decreased at rates faster than 5tones s for anisochronous tone sequences alone the effects of rate were more pronounced at short tone durations for the ohi listeners both presentation rate and tone duration had an impact o

strong convergence rate in averaging principle for stochastic fitzhugh nagumo system with two time scales abstract this article deals with averaging principle for stochastic fitzhugh nagumo system with different time scales under suitable conditions the existence of an averaging equation eliminating the fast variable for this coupled system is proved and as a consequence the system can be reduced to a single stochastic ordinary equation with a modified coefficient moreover the rate of convergence for the slow component towards the solution of the averaging equation is of order 1 2

age related changes in within and between channel gap detection using sinusoidal stimuli pure tone gap stimuli with identical within channel or dissimilar between channel marker frequencies of 1 and 2 khz were presented to young and old listeners in a two interval forced choice gap detection task to estimate the influence of extraneous duration cues on gap detection thresholds in the between channel conditions were obtained for two different sets of reference stimuli reference stimuli that were matched to the overall duration of the gap stimulus i e two markers plus the gap and reference stimuli that were fixed at the combined duration of the two markers excluding the gap results from within channel conditions were consistent with previous studies i e there were small but highly reliable age differences smaller gap thresholds at longer marker durations and an interaction between the two variables in between channel conditions however age differences were not as clear cut rather the effect of age varied as a function of duration cue and was more pronounced when stimuli were matched for overall duration than when the duration of the reference tone was fixed

examining the use of a time varying loudness algorithm for quantifying characteristics of nonlinearly propagated noise l a previous letter by gee et al j acoust soc am 121 el1 el7 2007 revealed likely shortcomings in using common stationary long term spectrum based measures to quantify the perception of nonlinearly propagated noise here the glasberg and moore j audio eng soc 50 331 342 2002 algorithm for time varying loudness is investigated their short term loudness when applied to a shock containing broadband signal and a phase randomized signal with equivalent long term spectrum does not show a significant difference in loudness between the signals further analysis and discussion focus on the possible utility of the instantaneous loudness and the need for additional investigation in this area

temporal integration at 6 khz as a function of masker bandwidth thresholds were measured for a 6 khz sinusoidal signal presented within a 500 ms masker the masker was either a bandpass gaussian noise of varying bandwidth or a sinusoid of the same frequency as the signal the spectrum level of the noise masker was kept constant at 20 db spl and the level of the sinusoidal masker was 40 db spl thresholds for signal durations between 2 and 300 ms were measured for masker bandwidths ranging from 60 to 12 000 hz the masker was spectrally centered around 6 khz for masker bandwidths less than 600 hz the slope of the temporal integration function decreased with decreasing masker bandwidth the results are not consistent with current models of temporal integration or temporal resolution it is suggested that the results at narrow bandwidths can be understood in terms of changes in the power spectrum of the stimulus envelope or modulation spectrum according to this view the onset and offset ramps of the signal introduce detectable high frequency components into the modulation spectrum which provide a salient cue in narrowband maskers for broadband maskers these high frequency components are masked by the inherent rapid fluctuations in the masker envelope additionally for signal durations between 7 and 80 ms signal thresholds decreased by up to 5 db as the masker bandwidth increased from 1200 to 12 000 hz the mechanisms underlying this effect are not yet fully understood

infinite dimensional reductive monoids associated to highest weight representations of kac moody groups abstract starting with a highest weight representation of a kac moody group over the complex numbers we construct a monoid whose unit group is the image of the kac moody group under the representation multiplied by the nonzero complex numbers we show that this monoid has similar properties to those of a j irreducible reductive linear algebraic monoid in particular the monoid is unit regular and has a bruhat decomposition and the idempotent lattice of the generalized renner monoid of the bruhat decomposition is isomorphic to the face lattice of the convex hull of the weyl group orbit of the highest weight

root polytopes triangulations and the subdivision algebra i the type a n root polytope p a n is the convex hull in r n 1 of the origin and the points e i e j for 1 i j n 1 given a tree t on the vertex set n 1 the associated root polytope p t is the intersection of p a n with the cone generated by the vectors e i e j where i j e t i j the reduced forms of a certain monomial m t in commuting variables x ij under the reduction x ij x jk x ik x ij x jk x ik x ik can be interpreted as triangulations of p t using these triangulations the volume and ehrhart polynomial of p t are obtained if we allow variables x ij and x kl to commute only when i j k l are distinct then the reduced form of m t is unique and yields a canonical triangulation of p t in which each simplex corresponds to a noncrossing alternating forest most generally in the noncommutative case which was introduced in the form of a noncommutative quadratic algebra by kirillov the reduced forms of all monomials are unique

explicit construction of an inertial manifold for a reaction diffusion equation abstract an inertial manifold is constructed for the scalar reaction diffusion equation u t vu xx u with a cubic nonlinearity uniform bounds are obtained for the number of zeros along solutions to the variational equations satisfied by the difference of two elements on the unstable manifolds of equilibria this uniformity leads to the global parameterization of the attractor as a function defined in the linear unstable manifold of the least stable equilibrium by the introduction of local techniques near each equilibrium we succeed in constructing an inertial manifold of lowest possible dimension

age related differences in discrimination of an interval separating onsets of successive tone bursts as a function of interval duration the study measured listener sensitivity to increments in the inter onset interval ioi separating pairs of successive 20 ms 4000 hz tone pulses a silent interval between the tone pulses was adjusted across conditions to create reference tonal ioi values of 25 600ms for each condition a duration dl for increments of the tonal ioi was measured in listeners comprised of young normal hearing adults and two groups of older adults with and without high frequency hearing loss discrimination performance of all listeners was poorest for the shorter reference iois and improved to stable levels for longer reference intervals exceeding about 200ms temporal sensitivity of the young listeners was significantly better than that of the elderly listeners in each condition with the largest age related differences observed for the shortest reference interval age related differences were also observed for duration dls measured using single 4000 hz tone bursts set to three reference durations in the range 50 200ms t

the hodge theory of soergel bimodules we prove soergel s conjecture on the characters of indecomposable soergel bimodules we deduce that kazhdan lusztig polynomials have positive coecients for arbitrary coxeter systems using results of soergel one may deduce an algebraic proof of the kazhdan lusztig conjecture

faces and maximizer subsets of highest weight modules abstract in this paper we study general highest weight modules v over a complex finite dimensional semisimple lie algebra g we present three formulas for the set of weights of a large family of modules v which include but are not restricted to all simple modules and all parabolic verma modules these formulas are direct and do not involve cancellations and were not previously known in the literature our results extend the notion of the weyl polytope to general highest weight g modules v we also show that for all simple modules the convex hull of the weights is a w j invariant polyhedron for some parabolic subgroup w j we compute its vertices faces and symmetries more generally we also do this for all parabolic verma modules and for all modules v with highest weight not on a simple root hyperplane to show our results we extend the notion of convexity to arbitrary additive subgroups a r of coefficients our techniques enable us to completely classify weak a faces of the support sets wt v in the process extending classical results of satake borel tits vinberg and casselman as well as modern variants by chari dolbin ridenour and cellini marietti to general highest weight modules

lie algebra modules with finite dimensional weight spaces i let g denote a reductive lie algebra over an algebraically closed field of characteristic zero and let 4 denote a cartan subalgebra of g in this paper we study finitely generated g modules that decompose into direct sums of finite dimensional 4 weight spaces we show that the classification of irreducible modules in this category can be reduced to the classification of a certain class of irreducible modules those we call torsion free modules we also show that if g is a simple lie algebra that admits a torsion free module then g is of type a or c

the role of stimulus complexity spectral overlap and pitch for gap detection thresholds in young and old listeners thresholds for detecting a gap between two complex tones were determined for young listeners with normal hearing and old listeners with mild age related hearing loss the leading tonal marker was always a 20 ms 250 hz complex tone with energy at 250 500 750 and 1000 hz the lagging marker also tonal could differ from the leading marker with respect to fundamental frequency f0 the presence versus absence of energy at f0 and the degree to which it overlapped spectrally with the leading marker all stimuli were presented with steeper 1 ms and less steep 4 ms envelope rise and fall times f0 differences decreases in the degree of spectral overlap between the markers and shallower envelope shape all contributed to increases in gap detection thresholds age differences for gap detection of complex sounds were generally small and constant when gap detection thresholds were measured on a log scale when comparing the results for complex sounds to thresholds obtained for pure tones in a previous study by heinrich and schneider 2006 j acoust soc am 119 2316 2326 thresholds increased in an orderly fashion from markers with identical within channel pure tones to different between channel pure tones to complex sounds this pattern of results was true for listeners of both ages although younger listeners had smaller thresholds overall

aging and temporal discrimination in auditory sequences this study examined age related changes in temporal sensitivity to increments in the inter onset intervals ioi of successive components in tonal sequences temporal discrimination was examined using reference stimulus patterns consisting of five 50 ms 4000 hz components with equal tonal iois selected from the range 100 600 ms discrimination was examined in separate conditions by measuring the relative difference limen dl for increments of tonal ioi in comparison sequences in some conditions comparison sequences featured equal increments of all tonal iois to examined listener sensitivity to uniform changes of sequence rate or tempo other conditions measured the dl for increments of a single target ioi within otherwise uniform rate comparison sequences for these measurements the single target ioi was either fixed in sequence location or randomized in location across listening trials listeners in the study included four groups of young and elderly adults with and without high frequency hearing loss the results for all listeners showed the relative dl for rate discrimination to decrease from a maximum at the 100 ms ioi to a smaller stable value across the range of longer sequence ioi all listeners also exhibited larger relative dls for discrimination of single target intervals compared to rate discrimination for equivalent reference ioi values older listeners showed poorer performance than younger listeners in all conditions with the largest age differences observed for discrimination of brief single intervals that were varied randomly in sequence location none of the results revealed significant effects of hearing loss on performance of younger and older listeners

forward masking adaptation or integration the aim of this study was to attempt to distinguish between neural adaptation and persistence or temporal integration as possible explanations of forward masking thresholds were measured for a sinusoidal signal as a function of signal duration for conditions where the delay between the masker offset and the signal offset the offset offset interval was fixed the masker was a 200 ms broadband noise presented at a spectrum level of 40 db re 20 pa and the signal was a 4 khz sinusoid gated with 2 ms ramps the offset offset interval was fixed at various durations between 4 and 102 ms and signal thresholds were measured for a range of signal durations at each interval a substantial decrease in thresholds was observed with increasing duration for signal durations up to about 20 ms at short offset offset intervals the amount of temporal integration exceeded that normally found in quiet the results were simulated using models of temporal integration the temporal window model and adaptation for both models the inclusion of a peripheral nonlinearity similar to that observed physiologically in studies of the basilar membrane was essential in producing a good fit to the data both models were about equally successful in accounting for the present data however the temporal window model provided a somewhat better account of similar data from a simultaneous masking experiment using the same parameters this suggests that the linear time invariant properties of the temporal window approach are appropriate for modeling forward masking overall the results confirm that forward masking can be described in terms of peripheral nonlinearity followed by linear temporal integration at higher levels in the auditory system however the difference in predictions between the adaptation and integration models is relatively small meaning that influence of adaptation cannot be ruled out

on the variation in the cohomology of the symplectic form of the reduced phase space is called the momentum mapping of the hamiltonian t action given 1 1 the condition 1 2 just means that t acts along the fibers of j for the basic definitions and properties of non commutative hamiltonian group actions see am the results of this paper can easily be extended to hamiltonian actions of arbitrary compact connected lie groups by applying our results to the action of its maximal toms and using the equivariance of the momentum mapping for some more details see the remarks at the end of sect 2 we will assume throughout this paper that the momentum map is proper that is j i u is compact for each compact subset u of t now let r be a regular value of j that is t j tmm t is surjective for all meye j 1 4 then ye is a smooth submanifold of m compact because

cuing effects for informational masking the detection of a tone added to a random frequency multitone masker can be very poor even when the maskers have little energy in the frequency region of the signal this paper examines the effects of adding a pretrial cue to reduce uncertainty for the masker or the signal the first two experiments examined the effect of cuing a fixed frequency signal as the number of masker components and presentation methods were manipulated cue effectiveness varied across observers but could reduce thresholds by as much as 20 db procedural comparisons indicated observers benefited more from having two masker samples to compare with or without a signal cue than having a single interval with one masker sample and a signal cue the third experiment used random frequency signals and compared no cue signal cue and masker cue conditions and also systematically varied the time interval between cue offset and trial onset thresholds with a cued random frequency signal remained higher than for a cued fixed frequency signal for time intervals between the cue and trial of 50 ms or longer thresholds were approximately the same with a signal or a masker cue and lower than when there was no cue without a cue or with a masker cue analyses of possible decision strategies suggested observers attended to the potential signal frequencies particularly the highest signal frequency with a signal cue observers appeared to attend to the frequency of the subsequent signal

perceived tonal continuity through two noise bursts separated by silence three experiments measured the perceived continuity of two pure tones flankers through a masker containing a silence experiment 1 used a 2i 2afc procedure one interval contained two noise bursts separated by a silent gap and the other contained two noise bursts separated by a tone of the same duration as the silence discrimination between masker conditions was very accurate when the flankers were absent but was impaired substantially when the flankers were present this was taken as evidence that illusory flanker continuity during the silent gap was heard as similar to the physical presence of a tone in the gap in experiment 2 performance remained poor when the flankers were frequency glides aligned along a common trajectory performance improved significantly when the flankers were misaligned in trajectory in experiment 3 listeners rated directly perceived flanker continuity strong continuity was reported in the silent gap conditions for which poor performance had been observed in experiments

construction of inertial manifolds by elliptic regularization abstract in many cases an inertial manifold 2 m for an infinite dimensional dissipative dynamical system can be represented as the graph of a smooth function from a finite dimensional hilbert space hp to another hilbert space hq the invariance property of m means that can be written as the solution of a first order partial differential equation d p g1 p p a p g2 p p 0 over hp where g1 and g2 are nonlinear functions which depend on the original dynamical system and a is a suitably stable linear operator in this paper we use a method introduced by sacker r j sacker a new approach to the perturbation theory of invariant surface comm pure appl math 18 1965 717 732 for the study of finite dimensional dynamical systems to find inertial manifolds in the infinite dimensional setting this method involves replacing the first order equation for by the regularized elliptic equation e d p g1 p p a p g2 p p with suitable boundary conditions it is shown that if a satisfies a spectral gap condition then the solutions e of the elliptic equation converge to a weak solution of 0 as e 0 furthermore m graph is an invariant manifold for the given dynamical system

a family of koszul algebras arising from finite dimensional representations of simple lie algebras abstract let g be a finite dimensional simple lie algebra and let s g be the locally finite part of the algebra of invariants end c v s g g where v is the direct sum of all simple finite dimensional modules for g and s g is the symmetric algebra of g given an integral weight let be the subset of roots which have maximal scalar product with given a dominant integral weight and such that is a subset of the positive roots we construct a finite dimensional subalgebra s g of s g and prove that the algebra is koszul of global dimension at most the cardinality of using this we construct naturally an infinite dimensional non commutative koszul algebra of global dimension equal to the cardinality of the results and the methods are motivated by the study of the category of finite dimensional representations of the affine and quantum affine algebras

faces of highest weight modules and the universal weyl polyhedron abstract let v be a highest weight module over a kac moody algebra g and let conv v denote the convex hull of its weights we determine the combinatorial isomorphism type of conv v i e we completely classify the faces and their inclusions in the special case where g is semisimple this brings closure to a question studied by cellini and marietti 2015 7 for the adjoint representation and by khare 2016 2017 17 18 for most modules the determination of faces of finite dimensional modules up to the weyl group action and some of their inclusions also appears in previous works of satake 1960 25 borel and tits 1965 3 vinberg 1990 26 and casselman 1997 6 for any subset of the simple roots we introduce a remarkable convex cone which we call the universal weyl polyhedron which controls the convex hulls of all modules parabolically induced from the corresponding levi factor namely the combinatorial isomorphism type of the cone stores the classification of faces for all such highest weight modules as well as how faces degenerate as the highest weight gets increasingly singular to our knowledge this cone is new in finite and infinite type we further answer a question of michel brion by showing that the localization of conv v along a face is always the convex hull of the weights of a parabolically induced module finally as we determine the inclusion relations between faces representation theoretically from the set of weights without recourse to convexity we answer a similar question for highest weight modules over symmetrizable quantum groups

the effect of age on auditory spatial attention in conditions of real and simulated spatial separation the contributions of auditory and cognitive factors to age dependent differences in auditory spatial attention were investigated in conditions of real spatial separation the target sentence was presented from a central location and competing sentences were presented from left and right locations in conditions of simulated spatial separation different apparent spatial locations of the target and competitors were induced using the precedence effect the identity of the target was cued by a callsign presented either prior to or following each target sentence and the probability that the target would be presented at the three locations was specified at the beginning of each block younger and older adults with normal hearing sensitivity below 4khz completed all 16 conditions 2 spatial separation method 2 callsign conditions 4 probability conditions overall younger adults performed better than older adults for both age groups performance improved with target location certainty with a priori tar

attractors for partly dissipative reaction diffusion systems in rn in this paper we study the asymptotic behavior of solutions for the partly dissipative reaction diffusion equations in n we prove the asymptotic compactness of the solutions and then establish the existence of the global attractor in 2 n 2 n l l 2000 academic press

gap detection and the precedence effect in young and old adults thresholds for detecting a gap between two gaussian enveloped standard deviation 0 5 ms 2 khz tones were determined in young and old listeners the gap detection thresholds of old adults were more variable and about twice as large as those obtained from young adults moreover gap detection thresholds were not correlated with audiometric thresholds in either group estimates of the width of the temporal window of young subjects based on the detection of a gap between two tone pips were smaller than those typically obtained when a relatively long duration pure tone is interrupted moore et al j acoust soc am 85 1266 1275 1989 because the amount of time it takes to recover from an adapting stimulus is likely to affect gap detection thresholds glasberg et al j acoust soc am 81 1546 1556 1987 smaller estimates of temporal window size would be expected in this paradigm if the amount of adaptation produced by the first tone pip was negligible the larger gap detection thresholds of o

effects of age and sequence presentation rate on temporal order recognition the experiments examined the ability of younger and older listeners to identify the temporal order of sounds presented in tonal sequences the stimuli were three tone sequences that spanned two octave frequency range and listeners identified random permutations of tone order using labels of relative pitch some of the sequences featured uniform timing characteristics and the sequence duty cycle was varied across conditions to examine the relative influence of tonal durations and intertone interval on recognition performance across a range of sequence presentation rates other stimulus sequences featured nonuniform timing with unequal tone durations and intertone intervals the listeners were groups of younger and older persons with or without hearing loss results indicated that temporal order recognition was influenced primarily by sequence presentation rate independent of tonal duration tonal interval spacing or sequence timing characteristics the performance of older listeners was poorer than younger listeners but the age related recognition differences were independent of sequence presentation rate there were no consistent effects of hearing loss on temporal ordering performance

forward masking by sinusoidal and noise maskers a 2 khz sinusoid and a narrow band noise centered at 2 khz with the same total power served as maskers for a 2 khz sinusoidal signal we compare the forward masking produced by these two maskers 1 as a function of offset offset time for 5 and 35 ms signals 2 as a function of signal duration for a fixed offset onset time and 3 as a function of signal duration for a fixed offset offset time in all these comparisons we find that the noise and sinusoid not only produce different amounts of masking for the same experimental condition but they also show different trends for the same manipulation the important relations in these results are demonstrated in an additional set of conditions with a 1 khz signal in order to account for the differences observed in both experiments we argue that forward masking is determined by at least two factors we suggest signal energy as one factor and the presence or absence of differences in quality between masker and signal as another

determining nodes for partly dissipative reaction diffusion systems abstract in this paper we study the long time dynamical properties of the solutions of partly dissipative reaction diffusion systems of the form u t d u f x u g x v 0 x r n t 0 v t v h x u 0 the main result is that under appropriate assumptions the large time behavior of a solution is completely determined in certain sense if the large time behavior of the solution is known on a densely chosen yet finite set of points which are called determining nodes a concept initially introduced by foias and temam for the navier stokes equations math comput 43 1984 117

spectral barriers and inertial manifolds for time discretized dissipative equations the existence of inertial manifolds for dissipative nonlinear evolutionary equationsunder time discretizations of the semi implicit euler method is proved by using a generalized concept of spectral barrier for time discretized equations

existence of inertial manifolds for partly dissipative reaction diffusion systems in higher space dimensions abstract in this paper we prove the existence of inertial manifolds for a partly dissipative reaction diffusion system of the form formula where is a rectangular domain in r 2or a cubic domain in r 3 the proof is based on an abstract invariant manifold theorem for semiflows in a hilbert space which is proved by using the graph transform method the principle of spatial averaging also plays an important role in the proof

a vector partition function for the multiplicities of slkc abstract we use gelfand tsetlin diagrams to write down the weight multiplicity function for the lie algebra sl k c type ak 1 as a single partition function this allows us to apply known results about partition functions to derive interesting properties of the weight diagrams we relate this description to that of the duistermaat heckman measure from symplectic geometry which gives a large scale limit way to look at multiplicity diagrams we also provide an explanation for why the weight polynomials in the boundary regions of the weight diagrams exhibit a number of linear factors using symplectic geometry we prove that the partition of the permutahedron into domains of polynomiality of the duistermaat heckman function is the same as that for the weight multiplicity function and give an elementary proof of this for sl 4 c a3

abelian ideals in a borel subalgebra of a complex simple lie algebra let mathfrak g be a complex simple lie algebra and mathfrak b a fixed borel subalgebra of mathfrak g we describe the abelian ideals in mathfrak b in a uniform way that is independent of the classification of complex simple lie algebras as an application we derive a formula for the maximal dimension of a commutative lie subalgebra of mathfrak g

temporal integration of loudness in listeners with hearing losses of primarily cochlear origin to investigate how hearing loss of primarily cochlear origin affects the loudness of brief tones loudness matches between 5 and 200 ms tones were obtained as a function of level for 15 listeners with cochlear impairments and for seven age matched controls three frequencies usually 0 5 1 and 4 khz were tested in each listener using a two interval two alternative forced choice 2i 2afc paradigm with a roving level up down adaptive procedure results for the normal listeners generally were consistent with published data e g j acoust soc am 99 1633 1644 1996 the amount of temporal integration defined as the level difference between equally loud short and long tones varied nonmonotonically with level and was largest at moderate levels no consistent effect of frequency was apparent the impaired listeners varied widely but most showed a clear effect of level on the amount of temporal integration overall their results appear consistent with expectations based on knowledge of the general properties of their loudness growth functions and the equal loudness ratio hypothesis which states that the loudness ratio between equal spl long and brief tones is the same at all spls the impaired listeners amounts of temporal integration at high spls often were larger than normal although it was reduced near threshold when evaluated at equal sls the amount of temporal integration well above threshold usually was in the low end of the normal range two listeners with abrupt high frequency hearing losses slopes 50 db octave showed larger than normal maximal amounts of temporal integration 40 to 50 db this finding is consistent with the shallow loudness functions predicted by our excitation pattern model for impaired listeners in modeling sensorineural hearing loss edited by w jesteadt erlbaum mahwah nj 1997 pp 187 198 loudness functions derived from impaired listeners temporal integration functions indicate that restoration of loudness in listeners with cochlear hearing loss usually will require the same gain whether the sound is short or long

invariant manifolds for flows in banach spaces on presente une theorie des varietes invariantes lisses basee sur la methode classique de lyapunov penon pour des semi flots continus dans des espaces de banach

inertial manifolds associated to partly dissipative reaction diffusion systems abstract in a previous work we established the existence of finite dimensional attractors for partly dissipative reaction diffusion systems of two types systems with a polynomial growth nonlinearity and systems admitting an invariant region the aim of this article is to show that these problems possess inertial manifolds in space dimension n 2 these inertial manifolds contain the universal attractor attract exponentially all the solutions as time goes to infinity and due to the weak dissipation are here infinite dimensional our results are applied to several classical systems borrowed from mathematical biology physics and chemistry