Irreducible tensor approach to spin observables in the photoproduction of mesons with arbitrary spin-parity s{sup {pi}}

A theoretical formalism leading to elegant derivation of formulas for all spin observables is outlined for photoproduction of mesons with arbitrary spin-parity sπ. The salient features of this formalism, based on irreducible tensor techniques, are (i) the number of independent irreducible tensor amplitudes is 4(2s+1), (ii) a single compact formula is sufficient to express these amplitudes in terms of allowed electric and magnetic multipole amplitudes, and (iii) all the spin observables, including beam analyzing powers as well as the differential cross section, are expressible in terms of bilinear irreducible tensors of rank 0 to 2(s+1). The relationship between the irreducible tensor amplitudes and the helicity amplitudes is elucidated in general and explicit expressions for the helicity amplitudes are given in terms of the irreducible tensor amplitudes in the particular cases of pseudoscalar and vector meson photoproduction. The connection between the irreducible tensor amplitudes introduced here and the well-known Chew-Goldberger-Low-Nambu amplitudes for photoproduction of pseudoscalar mesons is also established

Irreducible tensor approach to spin observables in the photoproduction of mesons with arbitrary spin-parity sπ

A theoretical formalism leading to elegant derivation of formulas for all spin observables is outlined for photoproduction of mesons with arbitrary spin-parity sπ. The salient features of this formalism, based on irreducible tensor techniques, are (i) the number of independent irreducible tensor amplitudes is 4(2s+1), (ii) a single compact formula is sufficient to express these amplitudes in terms of allowed electric and magnetic multipole amplitudes, and (iii) all the spin observables, including beam analyzing powers as well as the differential cross section, are expressible in terms of bilinear irreducible tensors of rank 0 to 2(s+1). The relationship between the irreducible tensor amplitudes and the helicity amplitudes is elucidated in general and explicit expressions for the helicity amplitudes are given in terms of the irreducible tensor amplitudes in the particular cases of pseudoscalar and vector meson photoproduction. The connection between the irreducible tensor amplitudes introduced here and the well-known Chew-Goldberger-Low-Nambu amplitudes for photoproduction of pseudoscalar mesons is also established

Empirical determination of threshold partial wave amplitudes for pp ppÏ

Using the model-independent irreducible tensor approach to Ï production in pp collisions, we show theoretically that it is advantageous to measure experimentally the polarization of Ï, in addition to the proposed experimental study employing a polarized beam on a polarized target. © World Scientific Publishing Company

New nomenclature and DNA testing guidelines for myotonic dystrophy type 1(DM1)

Myotonic dystrophy (DM; OMIM 160900, also known as dystrophia myotonica, myotonia atrophica and Steinert disease) is an autosomal dominant myotonic myopathy associated with abnormalities of other organs, including eyes, heart, endocrine system, central and peripheral nervous systems, gastrointestinal organs, bone, and skin.1 The mutation underlying DM is an expansion of an unstable cytosine-thymine-guanine (CTG) trinucleotide repeat in the 3' untranslated region of the myotonic dystrophy protein kinase (DMPK) gene in chromosome 19q13.3.2-4 In 1994, Thornton et al.5 described an autosomal dominant disorder similar to DM without CTG repeat expansion at the DM locus. Ricker et al.6 named this disease "proximal myotonic myopathy" (PROMM; OMIM 600109) because of predominantly proximal muscle weakness without atrophy as opposed to the distal muscle involvement seen in DM. Subsequently, Meola et al.7 described a variant of PROMM with unusual myotonic and myopathic features, which they named "proximal myotonic myopathy syndrome," and Udd et al.8 described a PROMM-like family with dystrophic features, which they named "proximal myotonic dystrophy" (PDM). Researchers at the University of Minnesota9,10 found another multisystemic myotonic disorder that closely resembles DM with distal muscle weakness but no CTG repeat expansion. Because of the close phenotypic resemblance to DM, they called this disease "myotonic dystrophy type 2" (DM2; OMIM 602668). In 1998, Ranum et al.9 assigned the DM2 locus to chromosome 3q in a large kindred. Shortly after that, Ricker et al.11 found that the majority of German PROMM families show linkage to the DM2 locus. PDM was also mapped to this region (Krahe and Udd, personal communication, 1999). Whether PROMM, PDM, and DM2 represent different phenotypic expressions of a disease caused by the same mutation or if they are allelic disorders remains to be determined. It is also possible that these disorders are caused by mutations in different genes that are closely linked in the chromosome 3q region.12 Furthermore, the disease loci in some typical PROMM families11 and other families with multisystemic myotonic disorders have been excluded from both DM and DM2 loci. Because of the genetic and phenotypic heterogeneity in this group of disorders, it became necessary to establish a new nomenclature foreseeing the future discovery of new disease loci and phenotypic variability

Partial Loss of USP9X Function Leads to a Male Neurodevelopmental and Behavioral Disorder Converging on Transforming Growth Factor beta Signaling

BACKGROUND: The X-chromosome gene USP9X encodes a deubiquitylating enzyme that has been associated with neurodevelopmental disorders primarily in female subjects. USP9X escapes X inactivation, and in female subjects de novo heterozygous copy number loss or truncating mutations cause haploinsufficiency culminating in a recognizable syndrome with intellectual disability and signature brain and congenital abnormalities. In contrast, the involvement of USP9X in male neurodevelopmental disorders remains tentative.METHODS: We used clinically recommended guidelines to collect and interrogate the pathogenicity of 44 USP9X variants associated with neurodevelopmental disorders in males. Functional studies in patient-derived cell lines and mice were used to determine mechanisms of pathology.RESULTS: Twelve missense variants showed strong evidence of pathogenicity. We define a characteristic phenotype of the central nervous system (white matter disturbances, thin corpus callosum, and widened ventricles); global delay with significant alteration of speech, language, and behavior; hypotonia; joint hypermobility; visual system defects; and other common congenital and dysmorphic features. Comparison of in silico and phenotypical features align additional variants of unknown significance with likely pathogenicity. In support of partial loss-of-function mechanisms, using patient-derived cell lines, we show loss of only specific USP9X substrates that regulate neurodevelopmental signaling pathways and a united defect in transforming growth factor signaling. In addition, we find correlates of the male phenotype in Usp9x brain-specific knockout mice, and further resolve loss of hippocannpal-dependent learning and memory.CONCLUSIONS: Our data demonstrate the involvement of USP9X variants in a distinctive neurodevelopmental and behavioral syndrome in male subjects and identify plausible mechanisms of pathogenesis centered on disrupted transforming growth factor beta signaling and hippocampal function.Genetics of disease, diagnosis and treatmen