This work derives the linearized equations of motion, the Lagrangian density, the Hamiltonian density, and the canonical angular momentum density for general perturbations [∝ exp(imφ) with m = 0,±1, ..] of a geometrically thin self-gravitating, homentropic fluid disk including the pressure. The theory is applied to “eccentric,” m = ±1 perturbations of a geometrically thin Keplerian disk. We fin...

Life-history traits are influenced by environmental factors throughout the lifespan of an individual. The relative importance of past versus present environment on individual fitness, therefore, is a relevant question in populations that face the challenge of temporally varying environment. We studied the interacting effects of past and present density on body mass, condition, and survival in e...

background there is evidence in support of low bone density in young patients with disorders of phenylalanine metabolism; however, little is known about muscle and fat mass in these patients, especially in those with mild hyperphenylalaninemia (mhpa). objectives we aimed to evaluate body composition of children and adolescents with early-diagnosed disorders of phenylalanine metabolism. patients...

The Skyrme model is a non-linear field theory whose solitonic solutions, once quantised, describe atomic nuclei. The classical static soliton solutions, so-called Skyrmions, have interesting symmetries and can only be calculated numerically. Mathematically, these Skyrmions can be viewed as maps between two three-manifolds and, as such, their stable singularities can only be folds, cusps and swa...

this study was undertaken to assess the frequency of decreased bone mineral density and its risk factors as well as its impact on the quality of life during childhood among hemophiliac patients. materials and methods: thirty seven children with severe hemophilia a and b, referred to mofid children’s hospital during 2010, were selected. for all patients the joint score, body mass indexes, bone m...

since mammography images are in low-contrast, applying enhancement techniques as a pre-processing step are wisely recommended in classification of the abnormal lesions into benign or malignant. a new kind of structural enhancement is proposed by morphological operator which introduces an optimal gaussian kernel primitive, the kernel parameters are optimized the use of genetic algorithm­­. we al...