Stress-Energy Tensor and Ultraviolet Behaviour in Massive Integrable Quantum Field Theories

The short distance behaviour of massive integrable quantum field theories is analyzed in terms of the form factor approach. We show that the on-shell dynamics is compatible with different definitions of the stress-energy tensor $T_{\mu\nu}(x)$ of the theory. In terms of form factors, this is equivalent to having a possible non-zero matrix element $F_1$ of the trace of $T_{\mu\nu}$ on one-particle state. Each choice of $F_1$ induces a different scaling behaviour of the massive theory in the ultraviolet limit.Comment: 32 pages LATEX file (Three figures not included in the text) ISAS/EP/93/6

"Nonlinear" covariance matrix and portfolio theory for non-Gaussian multivariate distributions

This paper offers a precise analytical characterization of the distribution of returns for a portfolio constituted of assets whose returns are described by an arbitrary joint multivariate distribution. In this goal, we introduce a non-linear transformation that maps the returns onto gaussian variables whose covariance matrix provides a new measure of dependence between the non-normal returns, generalizing the covariance matrix into a non-linear fractional covariance matrix. This nonlinear covariance matrix is chiseled to the specific fat tail structure of the underlying marginal distributions, thus ensuring stability and good-conditionning. The portfolio distribution is obtained as the solution of a mapping to a so-called phi-q field theory in particle physics, of which we offer an extensive treatment using Feynman diagrammatic techniques and large deviation theory, that we illustrate in details for multivariate Weibull distributions. The main result of our theory is that minimizing the portfolio variance (i.e. the relatively ``small'' risks) may often increase the large risks, as measured by higher normalized cumulants. Extensive empirical tests are presented on the foreign exchange market that validate satisfactorily the theory. For ``fat tail'' distributions, we show that an adequete prediction of the risks of a portfolio relies much more on the correct description of the tail structure rather than on their correlations.Comment: Latex, 76 page

Peripheral Facial Nerve Palsy in Severe Systemic Hypertension: A Systematic Review

BACKGROUND Signs of nervous system dysfunction such as headache or convulsions often occur in severe systemic hypertension. Less recognized is the association between severe hypertension and peripheral facial nerve palsy. The aim of this study was to systematically review the literature on the association of peripheral facial palsy with severe hypertension. METHODS Systematic review of Medline, Embase, Web of Science, and Google Scholar from 1960 through December 2011 and report of two cases. RESULTS The literature review revealed 24 cases to which we add two cases with severe hypertension and peripheral facial palsy. Twenty-three patients were children. Palsy was unilateral in 25 cases, bilateral in one case, and recurred in nine. The time between the first facial symptoms and diagnosis of hypertension was a median of 45 days (range, 0 days-2 years). In five case series addressing the complications of severe hypertension in children, 41 further cases of peripheral facial palsy were listed out of 860 patients (4.8%). CONCLUSIONS The association between severe hypertension and peripheral facial palsy is mainly described in children. Arterial hypertension is diagnosed with a substantial delay. Outcome is favorable with adequate antihypertensive treatment. The pathophysiology is still debate

Oxidative potential associated with urban aerosol deposited into the respiratory system and relevant elemental and ionic fraction contributions

Size-segregated aerosol measurements were carried out at an urban and at an industrial site. Soluble and insoluble fractions of elements and inorganic ions were determined. Oxidative potential (OP) was assessed on the soluble fraction of Particulate Matter (PM) by ascorbic acid (AA), dichlorofluorescein (DCFH) and dithiothreitol (DTT) assays. Size resolved elemental, ion and OP doses in the head (H), tracheobronchial (TB) and alveolar (Al) regions were estimated using the Multiple-Path Particle Dosimetry (MPPD) model. The total aerosol respiratory doses due to brake and soil resuspension emissions were higher at the urban than at the industrial site. On the contrary, the doses of anthropic combustion tracers were generally higher at the industrial site. In general, the insoluble fraction was more abundantly distributed in the coarse than in the fine mode and vice versa for the soluble fraction. Consequently, for the latter, the percent of the total respiratory dose deposited in TB and Al regions increased. Oxidative potential assay (OPAA) doses were distributed in the coarse region; therefore, their major contribution was in the H region. The contribution in the TB and Al regions increased for OPDTT and OPDCFH

Nervous system dysfunction in Henoch-Schönlein syndrome: systematic review of the literature

Objective. CNS or peripheral nervous system dysfunction sometimes occurs in Henoch-Schönlein patients. Methods. We review all Henoch-Schönlein cases published after 1969 with CNS dysfunction without severe hypertension and neuroimaging studies (n = 35), cranial or peripheral neuropathy (n = 15), both CNS and peripheral nervous system dysfunction without severe hypertension (n = 2) or nervous system dysfunction with severe hypertension (n = 2). Forty-four of the 54 patients were <20 years of age. Results. In patients with CNS dysfunction without or with severe hypertension the following presentations were observed in decreasing order of frequency: altered level of consciousness, convulsions, focal neurological deficits, visual abnormalities and verbal disability. Imaging studies disclosed the following lesions: vascular lesions almost always involving two or more vessels, intracerebral haemorrhage, posterior subcortical oedema, diffuse brain oedema and thrombosis of the superior sagittal sinus. Following lesions were noted in the subjects with cranial or peripheral neuropathy without severe hypertension: peroneal neuropathy, peripheral facial palsy, Guillain-Barré syndrome, brachial plexopathy, posterior tibial nerve neuropathy, femoral neuropathy, ulnar neuropathy and mononeuritis multiplex. Persisting signs of either CNS (n = 9) or peripheral (n = 1) nervous system dysfunction were sometimes reported. Conclusions. In Henoch-Schönlein syndrome, signs of nervous system dysfunction are uncommon but clinically relevant. This review helps clinicians managing Henoch-Schönlein syndrome with nervous system dysfunctio

Correlation Functions Along a Massless Flow

A non-perturbative method based on the Form Factor bootstrap approach is proposed for the analysis of correlation functions of 2-D massless integrable theories and applied to the massless flow between the Tricritical and the Critical Ising Models.Comment: 11 pages (two figures not included in the text), Latex file, ISAS/EP/94/15

Boundary flows in minimal models

We discuss in this paper the behaviour of minimal models of conformal theory perturbed by the operator $\Phi_{13}$ at the boundary. Using the RSOS restriction of the sine-Gordon model, adapted to the boundary problem, a series of boundary flows between different set of conformally invariant boundary conditions are described. Generalizing the "staircase" phenomenon discovered by Al. Zamolodchikov, we find that an analytic continuation of the boundary sinh-Gordon model provides a flow interpolation not only between all minimal models in the bulk, but also between their possible conformal boundary conditions. In the particular case where the bulk sinh-Gordon coupling is turned to zero, we obtain a boundary roaming trajectory in the $c=1$ theory that interpolates between all the possible spin $S$ Kondo models.Comment: 13pgs, harvmac, 2 fig

1110 Improved real-time cine with the use of a 32-channel cardiac array and Karhunen-Loeve Transform filter

This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.Leader-member exchange (LMX) theory proposes that leaders develop different quality relationships with those they manage and this is predictive of work performance. While LMX quality has been viewed as univalent (ranging from low to high quality), this paper proposes that it can also be bivalent in nature (i.e., coexisting positive and negative thoughts towards the relationship), which we refer to as LMX ambivalence. A survey measure of LMX ambivalence is developed, and through three validation and two main studies, it is shown to have construct, discriminant, and incremental predictive validity beyond that of LMX quality. Hypotheses concerning LMX ambivalence and task performance are tested in two main studies and show that (1) LMX ambivalence is negatively related to performance regardless of LMX quality, (2) high levels of perceived support from the organization (Study 1) or coworkers (Study 2) nullify the negative association between LMX ambivalence and performance, and (3) high LMX ambivalence leads to more negative affect and in turn lower task performance, but only when coworker support is low (Study 2). These results show the importance of viewing LMX quality not only in terms of its absolute level (low vs. high quality) but also as a bivalent construct where both positive and negative cognitions can coexist. They also demonstrate the value of social support in buffering the negative effects of LMX ambivalence. Furthermore, our findings extend a central tenet of LMX theory by implying that LMX quality varies not only within groups (i.e., LMX differentiation) but also within leader-follower dyads

Form Factors of the Elementary Field in the Bullough-Dodd Model

We derive the recursive equations for the form factors of the local hermitian operators in the Bullough-Dodd model. At the self-dual point of the theory, the form factors of the fundamental field of the Bullough-Dodd model are equal to those of the fundamental field of the Sinh-Gordon model at a specific value of the coupling constant.Comment: 14 pages, LATEX file, ISAS/EP/92/208;USP-IFQSC/TH/92-5