a latent variable model for discrete multivariate psychometric waiting times a version of the discrete proportional hazards model is developed for psychometrical applications in such applications a primary covariate that influences failure times is a latent variable representing a psychological construct the metropolis hastings algorithm is studied as a method for performing marginal likelihood inference on the item parameters the model is illustrated with a real data example that relates the age at which teenagers first experience various substances to the latent ability to avoid the onset of such behaviors

maximum likelihood estimation via the ecm algorithm a general framework two major reasons for the popularity of the em algorithm are that its maximum step involves only complete data maximum likelihood estimation which is often computationally simple and that its convergence is stable with each iteration increasing the likelihood when the associated complete data maximum likelihood estimation itself is complicated em is less attractive because the m step is computationally unattractive in many cases however complete data maximum likelihood estimation is relatively simple when conditional on some function of the parameters being estimated

extremal laplacian energy of directed trees unicyclic digraphs and bicyclic digraphs abstract let a g and d g be the adjacency matrix of a digraph g with n vertices and the diagonal matrix of vertex outdegrees of g respectively then the laplacian matrix of the digraph g is l g d g a g the laplacian energy of a digraph g is defined as l e g i 1 n i 2 by using second spectral moment where 1 2 n are all the eigenvalues of l g of g in this paper by using arc shifting operation and out star shifting operation we determine the directed trees unicyclic digraphs and bicyclic digraphs which attain maximal and minimal laplacian energy among all digraphs with n vertices respectively

the skew energy of a digraph we are interested in the energy of the skew adjacency matrix of a directed graph d which is simply called the skew energy of d in this paper properties of the skew energy of d are studied in particular a sharp upper bound for the skew energy of d is derived in terms of the order of d and the maximum degree of its underlying undirected graph an infinite family of digraphs attaining the maximum skew energy is constructed moreover the skew energy of a directed tree is independent of its orientation and interestingly it is equal to the energy of the underlying undirected tree skew energies of directed cycles under different orientations are also computed some open problems are presented

on newforms for kohnen plus spaces in this article we investigate the plus space of level n where 4 1n is a square free not necessarily odd integer this is a generalization of kohnen s work we define a hecke isomorphism wp k of mk 1 2 4m onto m k 1 2 8m for any odd positive integer m the methods of the proof of the newform theory are this isomorphism waldspurger s theorem and the dimension identity

shimura lifts of weakly holomorphic modular forms we show how to realize the shimura lift of arbitrary level and character using the vector valued theta lifts of borcherds using the regularization of borcherds lift we extend the shimura lift to take weakly holomorphic modular forms of half integral weight to meromorphic modular forms of even integral weight having poles at cm points

ordering of oriented unicyclic graphs by skew energies ordering of the oriented unicyclic graphs with n vertices according to their minimal skew energies is investigated we derive the first 22 oriented unicyclic graphs for n 1784 and a series of oriented unicyclic graphs for 3 n 1783

a flexible latent trait model for response times in tests latent trait models for response times in tests have become popular recently one challenge for response time modeling is the fact that the distribution of response times can differ considerably even in similar tests in order to reduce the need for tailor made models a model is proposed that unifies two popular approaches to response time modeling proportional hazard models and the accelerated failure time model with log normally distributed response times this is accomplished by resorting to discrete time the categorization of response time allows the formulation of a response time model within the framework of generalized linear models by using a flexible link function item parameters of the proposed model can be estimated with marginal maximum likelihood estimation applicability of the proposed approach is demonstrated with a simulation study and an empirical application additionally means for the evaluation of model fit are suggested

on two geometric theta lifts the theta correspondence has been an important tool in studying cycles in locally symmetric spaces of orthogonal type in this paper we establish for the orthogonal group o p 2 an adjointness result between borcherds s singular theta lift and the kudla millson lift we extend this result to arbitrary signature by introducing a new singular theta lift for o p q on the geometric side this lift can be interpreted as a differential character in the sense of cheeger and simons for the cycles under consideration

heegner divisors l functions and harmonic weak maass forms recent works mostly related to ramanujan s mock theta functions make use of the fact that harmonic weak maass forms can be combinatorial generating functions generalizing works of waldspurger kohnen and zagier we prove that such forms also serve as generating functions for central values and derivatives of quadratic twists of weight 2 modular l functions to obtain these results we construct differentials of the third kind with twisted heegner divisor by suitably generalizing the borcherds lift to harmonic weak maass forms the connection with periods fourier coefficients derivatives of l functions and points in the jacobian of modular curves is obtained by analyzing the properties of these differentials using works of scholl waldschmidt and gross and zagier

an extension of partial likelihood methods for proportional hazard models to general transformation models on utilise un schema de reechantillonnage appele echantillonneur de vraisemblance pour calculer la vraisemblance partielle et les estimateurs de vraisemblance partielle maximum

weil representations associated with finite quadratic modules to any finite quadratic module that is a finite abelian group together with a non degenerate quadratic form it is possible to associate a representation of mathrm mp 2 mathbb z the metaplectic cover of the modular group this representation is usually referred to as a weil representation and our main result is a general explicit formula for its matrix coefficients this result completes earlier work by scheithauer in the case when the representation factors through mathrm sl 2 mathbb z furthermore our formula is given in a such a way that it is easy to implement efficiently on a computer

oriented unicyclic graphs with the first n 92 largest skew energies abstract let g be an oriented graph obtained by assigning an orientation to the edge set of a simple undirected graph g such that g becomes a directed graph let s g be the skew adjacency matrix of g the skew energy of g is defined as the sum of the absolute values of all eigenvalues of s g in this paper we provide a new method to compare the skew energies of two oriented graphs whose skew characteristic polynomials satisfy a given recurrence relation and determine the oriented unicyclic graphs of order n with the first n 9 2 largest skew energies for n 31

on the converse theorem for borcherds products abstract we prove a new converse theorem for borcherds multiplicative theta lift which improves the previously known results to this end we develop a newform theory for vector valued modular forms for the weil representation which might be of independent interest we also derive lower bounds for the ranks of the picard groups and the spaces of holomorphic top degree differential forms of modular varieties associated to orthogonal groups

the energy of a graph abstract the energy e g of a simple graph g is defined to be the sum of the absolute values of the eigen values of g if g is a k regular graph on n vertices then e g k k n 1 n k b 2 and this bound is sharp it is shown that for each 0 there exist infinitely many n for each of which there exists a k regular graph g of order n with k e g b 2 two graphs with the same number of vertices are equienergetic if they have the same energy we show that for any positive integer n 3 there exist two equienergetic graphs of order 4n that are not cospectral

4 regular oriented graphs with optimum skew energy abstract let g be a simple undirected graph and g be an oriented graph of g with the orientation and skew adjacency matrix s g the skew energy of the oriented graph g denoted by e s g is defined as the sum of the absolute values of all the eigenvalues of s g in this paper we characterize the underlying graphs of all 4 regular oriented graphs with optimum skew energy and give orientations of these underlying graphs such that the skew energy of the resultant oriented graphs indeed attain optimum it should be pointed out that there are infinitely many 4 regular connected optimum skew energy oriented graphs while the 3 regular case only has two graphs k 4 the complete graph on 4 vertices and q 3 the hypercube

energy of matrices abstract let m n c denote the space of n n matrices with entries in c we define the energy of a m n c as 1 e a k 1 n k t r a n where 1 n are the eigenvalues of a tr a is the trace of a and z denotes the modulus of z c if a is the adjacency matrix of a graph g then e a is precisely the energy of the graph g introduced by gutman in 1978 in this paper we compare the energy e with other well known energies defined over matrices then we find upper and lower bounds of e which extend well known results for the energies of graphs and digraphs also we obtain new results on energies defined over the adjacency laplacian and signless laplacian matrices of digraphs

on two families of transformations to additivity for binary response data summary two families of power transformations for probabilities are introduced to model symmetric and asymmetric departures from the logistic model the aim is to provide in a comprehensive way a representation of alternative scales in terms of which to carry out the analysis of binary response data maximum likelihood methods are employed to estimate an appropriate transformation using glim tests for detection of symmetric and asymmetric departures are proposed

on the skew energy of orientations of hypercubes abstract let d be a digraph of order n and 1 2 n denote all the eigenvalues of the skew adjacency matrix of d the skew energy e s d of d is defined as e s d i 1 n i in this paper it is proved that for any positive integer k 3 there exists a k regular graph of order n having an orientation d with e s d n k this work positively answers a problem proposed by adiga et al c adiga r balakrishnan wasin so the skew energy of a digraph linear algebra appl 432 2010 1825 1835 in addition a digraph is also constructed such that its skew energy is the same as the energy of its underlying graph

bicyclic oriented graphs with the second largest skew energy abstract let g be an oriented graph and p s g x det x i s g be the skew characteristic polynomial of its skew adjacency matrix s g the skew energy of g is defined to be the sum of the absolute values of eigenvalues of s g in this paper we firstly find a novel relation between the coefficients of skew characteristic polynomial of unicyclic graph with the third largest skew energy and bicyclic oriented graphs and then use it along with other techniques to characterize the bicyclic oriented graphs with the second largest skew energy