Workshop Summary

Recent progress in understanding the physics of B mesons and of CP violation, as presented to this Workshop, is put in historical perspective and summarized.Comment: 22 pages, 7 figures, invited talk presented at BCP4, Ise-Shima, Japan, February 19-23, 200

The Determination of the CKM Matrix

A general discussion of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is given and the importance stressed of determining the matrix elements as an essential part of understanding CP violation in and beyond the Standard Model. The status of knowledge of the matrix elements connecting the first and second generation quarks is reviewed. A perspective on determinations of the full CKM matrix is presented as an introduction to the separate contributions to the panel discussion that follows.Comment: Invited talk at Beauty 2000, Kibbutz Maagan, Israel, September 13-18, 2000; 6 pages; no figure

Effective Hamiltonian for ΔS=1 weak nonleptonic decays in the six-quark model

Strong-interaction corrections to the nonleptonic weak-interaction Hamiltonian are calculated in the leading-logarithmic approximation using quantum chromodynamics. Starting with a six-quark theory, the W boson, t quark, b quark, and c quark are successively considered as "heavy" and the effective Hamiltonian calculated. The resulting effective Hamiltonian for strangeness-changing nonleptonic decays involves u, d, and s quarks and has possible CP-violating pieces both in the usual (V-A)×(V-A) terms and in induced, "penguin"-type terms. Numerically, the CP-violating compared to CP-conserving parts of the latter terms are close to results calculated on the basis of the lowest-order "penguin" diagram

K→πe+e- in the six-quark model

The decay K→πe+e- is considered in the six-quark model. The effective Hamiltonian applicable to such decays is calculated in leading-logarithmic approximation and attention is focused on the magnitude of CP-violating effects

Radiative weak decays of baryons as single-quark transitions

Radiative weak decays are investigated in the context of the quark model assuming the basic transition is an s quark decaying to a d quark plus a photon. This assumption, which encompasses a number of more detailed models, is used to predict relative rates and angular distributions for radiative weak decays of baryons. The measured decay rate for Σ+→pγ and upper limit on that for Ξ-→Σ-γ are in disagreement with the predictions and appear to rule out such models

G2019S mutation in the leucine-rich repeat kinase 2 gene is not associated with multiple system atrophy

Multiple system atrophy (MSA) is characterized clinically by Parkinsonism, cerebellar dysfunction, and autonomic impairment. Multiple mutations in the LRRK2 gene are associated with parkinsonian disorders, and the most common one, the G2019S mutation, has been found in ∼1% of sporadic cases of Parkinsonism. In a well-characterized cohort of 136 subjects with probable MSA and 110 neurologically evaluated control subjects, none carried the G2019S mutation. We conclude that the G2019S mutation in the LRRK2 gene is unlikely to be associated with MSA. © 2007 Movement Disorder SocietyPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56014/1/21343_ftp.pd

Optical Coherence Tomography in Parkinsonian Syndromes

BACKGROUND/OBJECTIVE: Parkinson's disease (PD) and the atypical parkinsonian syndromes multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) are movement disorders associated with degeneration of the central nervous system. Degeneration of the retina has not been systematically compared in these diseases. METHODS: This cross-sectional study used spectral-domain optical coherence tomography with manual segmentation to measure the peripapillar nerve fiber layer, the macular thickness, and the thickness of all retinal layers in foveal scans of 40 patients with PD, 19 with MSA, 10 with CBS, 15 with PSP, and 35 age- and sex-matched controls. RESULTS: The mean paramacular thickness and volume were reduced in PSP while the mean RNFL did not differ significantly between groups. In PSP patients, the complex of retinal ganglion cell- and inner plexiform layer and the outer nuclear layer was reduced. In PD, the inner nuclear layer was thicker than in controls, MSA and PSP. Using the ratio between the outer nuclear layer and the outer plexiform layer with a cut-off at 3.1 and the additional constraint that the inner nuclear layer be under 46 µm, we were able to differentiate PSP from PD in our patient sample with a sensitivity of 96% and a specificity of 70%. CONCLUSION: Different parkinsonian syndromes are associated with distinct changes in retinal morphology. These findings may serve to facilitate the differential diagnosis of parkinsonian syndromes and give insight into the degenerative processes of patients with atypical parkinsonian syndromes