Non-Abelian discrete gauge symmetries in 4d string models

We study the realization of non-Abelian discrete gauge symmetries in 4d field theory and string theory compactifications. The underlying structure generalizes the Abelian case, and follows from the interplay between gaugings of non-Abelian isometries of the scalar manifold and field identifications making axion-like fields periodic. We present several classes of string constructions realizing non-Abelian discrete gauge symmetries. In particular, compactifications with torsion homology classes, where non-Abelianity arises microscopically from the Hanany-Witten effect, or compactifications with non-Abelian discrete isometry groups, like twisted tori. We finally focus on the more interesting case of magnetized branes in toroidal compactifications and quotients thereof (and their heterotic and intersecting duals), in which the non-Abelian discrete gauge symmetries imply powerful selection rules for Yukawa couplings of charged matter fields. In particular, in MSSM-like models they correspond to discrete flavour symmetries constraining the quark and lepton mass matrices, as we show in specific examples.Comment: 58 pages; minor typos corrected and references adde

Axion Protection from Flavor

The QCD axion fails to solve the strong CP problem unless all explicit PQ violating, Planck-suppressed, dimension n<10 operators are forbidden or have exponentially small coefficients. We show that all theories with a QCD axion contain an irreducible source of explicit PQ violation which is proportional to the determinant of the Yukawa interaction matrix of colored fermions. Generically, this contribution is of low operator dimension and will drastically destabilize the axion potential, so its suppression is a necessary condition for solving the strong CP problem. We propose a mechanism whereby the PQ symmetry is kept exact up to n=12 with the help of the very same flavor symmetries which generate the hierarchical quark masses and mixings of the SM. This "axion flavor protection" is straightforwardly realized in theories which employ radiative fermion mass generation and grand unification. A universal feature of this construction is that the heavy quark Yukawa couplings are generated at the PQ breaking scale.Comment: 16 pages, 2 figure

Raphtory: The temporal graph engine for Rust and Python

Raphtory is a platform for building and analysing temporal networks. The library includes methods for creating networks from a variety of data sources; algorithms to explore their structure and evolution; and an extensible GraphQL server for deployment of applications built on top. Raphtory's core engine is built in Rust, for efficiency, with Python interfaces, for ease of use. Raphtory is developed by network scientists, with a background in Physics, Applied Mathematics, Engineering and Computer Science, for use across academia and industry

Automated inter-rater reliability assessment and electronic data collection in a multi-center breast cancer study

<p>Abstract</p> <p>Background</p> <p>The choice between paper data collection methods and electronic data collection (EDC) methods has become a key question for clinical researchers. There remains a need to examine potential benefits, efficiencies, and innovations associated with an EDC system in a multi-center medical record review study.</p> <p>Methods</p> <p>A computer-based automated menu-driven system with 658 data fields was developed for a cohort study of women aged 65 years or older, diagnosed with invasive histologically confirmed primary breast cancer (N = 1859), at 6 Cancer Research Network sites. Medical record review with direct data entry into the EDC system was implemented. An inter-rater and intra-rater reliability (IRR) system was developed using a modified version of the EDC.</p> <p>Results</p> <p>Automation of EDC accelerated the flow of study information and resulted in an efficient data collection process. Data collection time was reduced by approximately four months compared to the project schedule and funded time available for manuscript preparation increased by 12 months. In addition, an innovative modified version of the EDC permitted an automated evaluation of inter-rater and intra-rater reliability across six data collection sites.</p> <p>Conclusion</p> <p>Automated EDC is a powerful tool for research efficiency and innovation, especially when multiple data collection sites are involved.</p

Imaging of Burkitt lymphoma in pediatric patients

The imaging procedures utilized at presentation in the diagnostic work-up of 19 children with Burkitt lymphoma were reviewed. The distribution of disease was compared to other tumors of childhood so that the most valuable modalities could be identified. Burkitt lymphoma is a rapidly growing tumor in the child, making it essential to suggest the diagnosis as quickly as possible so that biopsy and treatment can be instigated. The primary area of involvement was abdominal (15 of 19), gastrointestinal, intraperitoneal adenopathy, hepatic and pancreatic without retroperitoneal adenopathy. Pleural effusions were common without hilar and mediastinal adenopathy. This is in contrast to other tumors of childhood where mediastinal and hilar disease in the chest and retroperitoneal node involvement in the abdomen are common. Thus sonography is an excellent imaging modality, easily identifying the extent of the disease and so suggesting the diagnosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46683/1/247_2006_Article_BF02388718.pd

Short-term effects of amelogenin gene splice products A+4 and A-4 implanted in the exposed rat molar pulp

In order to study the short-time effects of two bioactive low-molecular amelogenins A+4 and A-4, half-moon cavities were prepared in the mesial aspect of the first maxillary molars, and after pulp exposure, agarose beads alone (controls) or beads soaked in A+4 or A-4 (experimental) were implanted into the pulp. After 1, 3 or 7 days, the rats were killed and the teeth studied by immunohistochemistry. Cell proliferation was studied by PCNA labeling, positive at 3 days, but decreasing at day 7 for A+4, whilst constantly high between 3 and 7 days for A-4. The differentiation toward the osteo/odontoblast lineage shown by RP59 labeling was more apparent for A-4 compared with A+4. Osteopontin-positive cells were alike at days 3 and 7 for A-4. In contrast, for A+4, the weak labeling detected at day 3 became stronger at day 7. Dentin sialoprotein (DSP), an in vivo odontoblast marker, was not detectable until day 7 where a few cells became DSP positive after A-4 stimulation, but not for A+4. These results suggest that A +/- 4 promote the proliferation of some pulp cells. Some of them further differentiate into osteoblast-like progenitors, the effects being more precocious for A-4 (day 3) compared with A+4 (day 7). The present data suggest that A +/- 4 promote early recruitment of osteogenic progenitors, and evidence functional differences between A+4 and A-4

Mild Cognitive Impairment as a risk factor for Parkinson's disease dementia

Background The International Parkinson and Movement Disorders Society criteria for mild cognitive impairment in Parkinson’s disease were recently formulated. Objectives The aim of this international study was to evaluate the predictive validity of the comprehensive (level II) version of these criteria by assessment of their contribution to the hazard of Parkinson’s disease dementia. Methods Individual patient data were selected from four separate studies on cognition in Parkinson’s disease that provided information on demographics, motor examination, depression, neuropsychological examination suitable for application of level II criteria, and longitudinal follow-up for conversion to dementia. Survival analysis evaluated the predictive value of level II criteria for cognitive decline towards dementia as expressed by the relative hazard of dementia. Results A total of 467 patients were included. The analyses showed a clear contribution of impairment according to level II mild cognitive impairment criteria, age and severity of Parkinson’s disease motor symptoms to the hazard of dementia. There was a trend of increasing hazard of dementia with declining neuropsychological performance. Conclusions This is the first large international study evaluating the predictive validity of level II mild cognitive impairment criteria for Parkinson’s disease. The results showed a clear and unique contribution of classification according to level II criteria to the hazard of Parkinson’s disease dementia. This finding supports their predictive validity and shows that they contribute important new information on the hazard of dementia, beyond known demographic and Parkinson’s disease specific factors of influence.Michael J. Fox Foundation Dutch Parkinson Foundatio