background achalasia is the most recognized motor disorder of the esophagus.because it is an uncommon disease, most studies have reviewed small numbers of patients. here, we report demographic, clinical features and treatment outcomes in 700 achalasia patients. methods in all patients, diagnosis was established based on clinical, radiological, endoscopic and manometric criteria. a questionnaire...

Let P be a selfadjoint elliptic operator of order m > 0 acting on the sections of a Hermitian vector bundle over a compact Riemannian manifold of dimension n. General arguments show that its zeta and eta functions may have poles only at points of the form s = k m , where k ranges over all non-zero integers ≤ n. In this paper, we construct elementary and explicit examples of perturbations of P w...