On the Structure of the Fusion Ideal

We prove that there is a finite level-independent bound on the number of relations defining the fusion ring of positive energy representations of the loop group of a simple, simply connected Lie group. As an illustration, we compute the fusion ring of $G_2$ at all levels

Hamiltonization of Nonholonomic Systems and the Inverse Problem of the Calculus of Variations

We introduce a method which allows one to recover the equations of motion of a class of nonholonomic systems by finding instead an unconstrained Hamiltonian system on the full phase space, and to restrict the resulting canonical equations to an appropriate submanifold of phase space. We focus first on the Lagrangian picture of the method and deduce the corresponding Hamiltonian from the Legendre transformation. We illustrate the method with several examples and we discuss its relationship to the Pontryagin maximum principle.Comment: 23 pages, accepted for publication in Rep. Math. Phy

Prepregnancy Diabetes and Breastfeeding Cessation among Black Women in the United States

The incidence of diabetes is rising, and with it, the number of pregnancies affected by diabetes. U.S. black women have a disproportionately high prevalence of diabetes and lower rates of breastfeeding. Objective: The objective of this study was to quantify the relationship between diabetes before pregnancy and breastfeeding duration among black women in the United States. Materials and Methods: We analyzed women from the Black Women's Health Study (N = 59,000) to assess the relationship between prepregnancy diabetes and time to breastfeeding cessation occurring up to 24 months postdelivery using Kaplan-Meier survival curves, log rank tests, and Cox proportional hazards models. The study population included primiparous women with births between 1995 and 2009 (N = 3,404). Obesity, hypertension before pregnancy, and family history of diabetes were examined for effect modification. Results: Survival curves demonstrated a markedly reduced duration of breastfeeding in women who had been diagnosed with prepregnancy diabetes (p < 0.01). The hazard ratio for breastfeeding cessation for women with prepregnancy diabetes was 1.5 (95% confidence interval 1.1-2.0) compared with women without prepregnancy diabetes after control for age, body mass index (BMI) at age 18, prepregnancy BMI, other metabolic factors, demographics, and health behaviors. Conclusions: Our results suggest that prepregnancy diabetes is a strong predictor of curtailed breastfeeding duration, even after control for BMI. This underscores the need for targeted lactation support for diabetic women

Cumulative Lactation and Onset of Hypertension in African-American Women

Hypertension affects nearly 1 of 3 women and contributes to cardiovascular disease, the leading cause of death in the United States. Breastfeeding leads to metabolic changes that could reduce risks of hypertension. Hypertension disproportionately affects black women, but rates of breastfeeding among black women lag behind those in the general population. In the BlackWomen'sHealthStudy (n = 59,001), we conducted a nested case-control analysis using unconditional logistic regression to estimate the association between breastfeeding and incident hypertension at ages 40-65 years using data collected from 1995 to 2011. Controls were frequency-matched 2:1 to 12,513 hypertensive women by age and questionnaire cycle. Overall, there was little evidence of association between ever breastfeeding and incident hypertension (odds ratio = 0.97, 95% confidence interval: 0.92, 1.02). However, age modified the relationship (P = 0.02): Breastfeedingwas associated with reduced risk of hypertension at ages 40-49 years (odds ratio = 0.92, 95%confidence interval: 0.85, 0.99) but not at older ages. In addition, risk of hypertension at ages 40-49 years decreased with increasing duration of breastfeeding (P for trend = 0.08). Our results suggest that long-duration breastfeeding may reduce the risk of incident hypertension in middle age. Addressing breastfeeding as a potential preventative health behavior is particularly compelling because it is required for only a discrete period of time

POEtic Tissue: An Integrated Architecture for Bio-inspired Hardware

It is clear to all, after a moments thought, that nature has much wemight be inspired by when designing our systems, for example: robustness, adaptability and complexity, to name a few. The implementation of bio-inspired systems in hardware has however been limited, and more often than not been more a matter of artistry than engineering. The reasons for this are many, but one of the main problems has always been the lack of a universal platform, and of a proper methodology for the implementation of such systems. The ideas presented in this paper are early results of a new research project, "Reconfigurable POEtic Tissue". The goal of the project is the development of a hardware platform capable of implementing systems inspired by all three major axes (phylogenesis, ontogenesis, and epigenesis) of bio-inspiration, in digital hardware

A High Statistics Search for Ultra-High Energy Gamma-Ray Emission from Cygnus X-3 and Hercules X-1

We have carried out a high statistics (2 Billion events) search for ultra-high energy gamma-ray emission from the X-ray binary sources Cygnus X-3 and Hercules X-1. Using data taken with the CASA-MIA detector over a five year period (1990-1995), we find no evidence for steady emission from either source at energies above 115 TeV. The derived upper limits on such emission are more than two orders of magnitude lower than earlier claimed detections. We also find no evidence for neutral particle or gamma-ray emission from either source on time scales of one day and 0.5 hr. For Cygnus X-3, there is no evidence for emission correlated with the 4.8 hr X-ray periodicity or with the occurrence of large radio flares. Unless one postulates that these sources were very active earlier and are now dormant, the limits presented here put into question the earlier results, and highlight the difficulties that possible future experiments will have in detecting gamma-ray signals at ultra-high energies.Comment: 26 LaTeX pages, 16 PostScript figures, uses psfig.sty to be published in Physical Review

FGF receptor genes and breast cancer susceptibility: results from the Breast Cancer Association Consortium

Background:Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium. Methods:Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression. Results:Little evidence of association with breast cancer risk was observed for SNPs in the FGF receptor genes. The strongest evidence in European women was for rs743682 in FGFR3; the estimated per-allele odds ratio was 1.05 (95 confidence interval=1.02-1.09, P=0.0020), which is substantially lower than that observed for SNPs in FGFR2. Conclusion:Our results suggest that common variants in the other FGF receptors are not associated with risk of breast cancer to the degree observed for FGFR2. © 2014 Cancer Research UK