新疆少数民族中学"体育与健康"课程教学现状的调查与研究

本对新疆南、北疆、东疆地区和乌鲁木齐市的101所民族中学进行实地的调查研究，通过对各民族中学体育教学中大纲、教材、场地器材、汉语授课、男女生分班情况、教师培训、教学计划以及对课程改革的认识等方面的分析．进一步了解新疆各地区民族中学学校体育状况，特别是“体育与健康”课程实施后，各地区民族中学学校体育教学现状以及所面临的问题，旨在加快新疆少数民族中学的体育教学改革和《体育与健康》课程教学研究。为新疆教育主管部门制定实施“体育与健康”课程教学提供决策依据。     

Structure and reactivity of a mononuclear non-haem iron(III)-peroxo complex

Oxygen-containing mononuclear iron species--iron(III)-peroxo, iron(III)-hydroperoxo and iron(IV)-oxo--are key intermediates in the catalytic activation of dioxygen by iron-containing metalloenzymes. It has been difficult to generate synthetic analogues of these three active iron-oxygen species in identical host complexes, which is necessary to elucidate changes to the structure of the iron centre during catalysis and the factors that control their chemical reactivities with substrates. Here we report the high-resolution crystal structure of a mononuclear non-haem side-on iron(III)-peroxo complex, [Fe(III)(TMC)(OO)](+). We also report a series of chemical reactions in which this iron(III)-peroxo complex is cleanly converted to the iron(III)-hydroperoxo complex, [Fe(III)(TMC)(OOH)](2+), via a short-lived intermediate on protonation. This iron(III)-hydroperoxo complex then cleanly converts to the ferryl complex, [Fe(IV)(TMC)(O)](2+), via homolytic O-O bond cleavage of the iron(III)-hydroperoxo species. All three of these iron species--the three most biologically relevant iron-oxygen intermediates--have been spectroscopically characterized; we note that they have been obtained using a simple macrocyclic ligand. We have performed relative reactivity studies on these three iron species which reveal that the iron(III)-hydroperoxo complex is the most reactive of the three in the deformylation of aldehydes and that it has a similar reactivity to the iron(IV)-oxo complex in C-H bond activation of alkylaromatics. These reactivity results demonstrate that iron(III)-hydroperoxo species are viable oxidants in both nucleophilic and electrophilic reactions by iron-containing enzymes.     

Genome-wide association study in individuals of South Asian ancestry identifies six new type 2 diabetes susceptibility loci

We carried out a genome-wide association study of type-2 diabetes (T2D) in individuals of South Asian ancestry. Our discovery set included 5,561 individuals with T2D (cases) and 14,458 controls drawn from studies in London, Pakistan and Singapore. We identified 20 independent SNPs associated with T2D at P < 10(-4) for testing in a replication sample of 13,170 cases and 25,398 controls, also all of South Asian ancestry. In the combined analysis, we identified common genetic variants at six loci (GRB14, ST6GAL1, VPS26A, HMG20A, AP3S2 and HNF4A) newly associated with T2D (P = 4.1 × 10(-8) to P = 1.9 × 10(-11)). SNPs at GRB14 were also associated with insulin sensitivity (P = 5.0 × 10(-4)), and SNPs at ST6GAL1 and HNF4A were also associated with pancreatic beta-cell function (P = 0.02 and P = 0.001, respectively). Our findings provide additional insight into mechanisms underlying T2D and show the potential for new discovery from genetic association studies in South Asians, a population with increased susceptibility to T2D.     

部门动态投资系数的求取方法探讨

本文从理论和实践两个方面对动态投入产出法中动态投资的概念、投资系数的求取等进行了研究,提出了部门动态投资系数的求取方法,即一次性投资与多次性投资的综合方法。在此基础上,还给出了投资系数的修正方法,分析了影响投资系数求取的因素。最后,给出了投资系数求取过程中的误差分析方法。     

Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Ocean

Roughly 60% of the Earth's outer surface is composed of oceanic crust formed by volcanic processes at mid-ocean ridges. Although only a small fraction of this vast volcanic terrain has been visually surveyed or sampled, the available evidence suggests that explosive eruptions are rare on mid-ocean ridges, particularly at depths below the critical point for seawater (3,000 m). A pyroclastic deposit has never been observed on the sea floor below 3,000 m, presumably because the volatile content of mid-ocean-ridge basalts is generally too low to produce the gas fractions required for fragmenting a magma at such high hydrostatic pressure. We employed new deep submergence technologies during an International Polar Year expedition to the Gakkel ridge in the Arctic Basin at 85 degrees E, to acquire photographic and video images of 'zero-age' volcanic terrain on this remote, ice-covered ridge. Here we present images revealing that the axial valley at 4,000 m water depth is blanketed with unconsolidated pyroclastic deposits, including bubble wall fragments (limu o Pele), covering a large (>10 km(2)) area. At least 13.5 wt% CO(2) is necessary to fragment magma at these depths, which is about tenfold the highest values previously measured in a mid-ocean-ridge basalt. These observations raise important questions about the accumulation and discharge of magmatic volatiles at ultraslow spreading rates on the Gakkel ridge and demonstrate that large-scale pyroclastic activity is possible along even the deepest portions of the global mid-ocean ridge volcanic system.     

100-metre-diameter moonlets in Saturn's A ring from observations of 'propeller' structures

Saturn's main rings are composed predominantly of water-ice particles ranging between about 1 centimetre and 10 metres in radius. Above this size range, the number of particles drops sharply, according to the interpretation of spacecraft and stellar occultations. Other than the gap moons Pan and Daphnis (the provisional name of S/2005 S1), which have sizes of several kilometres, no individual bodies in the rings have been directly observed, and the population of ring particles larger than ten metres has been essentially unknown. Here we report the observation of four longitudinal double-streaks in an otherwise bland part of the mid-A ring. We infer that these 'propeller'-shaped perturbations arise from the effects of embedded moonlets approximately 40 to 120 m in diameter. Direct observation of this phenomenon validates models of proto-planetary disks in which similar processes are posited. A population of moonlets, as implied by the size distribution that we find, could help explain gaps in the more tenuous regions of the Cassini division and the C ring. The existence of such large embedded moonlets is most naturally compatible with a ring originating in the break-up of a larger body, but accretion from a circumplanetary disk is also plausible if subsequent growth onto large particles occurs after the primary accretion phase has concluded.