Xiaoguang Ma

Learn More
Let A be an associative unital algebra over a field k. Let us regard it as a Lie algebra with bracket [a, b] = ab − ba, and consider the terms of its lower central series Li(A) defined inductively by L1(A) = A and Li+1(A) = [A,Li(A)]. Denote by Mi(A) the two-sided ideal in A generated by Li(A): Mi(A) = ALi(A)A, and let Qi(A) = A/Mi(A). Thus Qi(A) is the(More)
BACKGROUND Short sleep duration has been found to be closely related to several endocrine and metabolic dysfunctions. However, evidence of the association between insufficient sleep and bone health was limited. OBJECTIVE The present study was aimed to examine the relationships between sleep duration and bone mineral density (BMD) in Chinese women. (More)
OBJECTIVE To investigate ethnic difference in the associations of BMI with comorbidity, mortality, and body composition between mainland Chinese and U.S. whites. METHODS Ethnic-comparison study using data from China Health and Nutrition Survey, U.S. National Health and Nutrition Examination Survey, and data from Zhejiang University (China) and Columbia(More)
PURPOSE On the basis of a neighborhood deprivation index (NDI), this study aims to examine the association between neighborhood deprivation and preterm birth (PTB) by applying propensity score matching (PSM) methods. METHODS NDI was calculated for all census tracts in South Carolina based on the US Census data. Live births in South Carolina during 2008 to(More)
OBJECTIVE To investigate the association of regional fat depots with metabolic risk factors in Chinese women. DESIGN Total and regional fat depots including android fat and gynoid fat were measured by dual-energy X-ray absorptiometry. Central fat distribution was defined as android:gynoid fat ratio. Metabolic risk factors were defined as elevated TAG,(More)
Let G = GL(N), K = GL(p)× GL(q), where p + q = N , and let n be a positive integer. We construct a functor from the category of HarishChandra modules for the pair (G,K) to the category of representations of the degenerate affine Hecke algebra of type Bn, and a functor from the category of K-monodromic twisted D-modules on G/K to the category of(More)
OBJECTIVE To examine the association of both perceived and geographic neighbourhood food access with food security status among households with children. DESIGN This was a cross-sectional study in which participants' perceptions of neighbourhood food access were assessed by a standard survey instrument, and geographic food access was evaluated by distance(More)
The degenerate affine Hecke algebra (dAHA) of any Coxeter group was defined by Drinfeld and Lusztig([Dri],[Lus]). It is generated by the group algebra of the Coxeter group and by the commuting generators yi with some relations. The degenerate double affine Hecke algebra (dDAHA) of a root system was introduced by Cherednik (see [Ch]). It is generated by the(More)