Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of ...R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→μ^{+}μ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.
In this note, we consider the problems of stochastic stability and sliding-mode control for a class of linear continuous-time systems with stochastic jumps, in which the jumping parameters are ...modeled as a continuous-time, discrete-state homogeneous Markov process with right continuous trajectories taking values in a finite set. By using Linear matrix inequalities (LMIs) approach, sufficient conditions are proposed to guarantee the stochastic stability of the underlying system. Then, a reaching motion controller is designed such that the resulting closed-loop system can be driven onto the desired sliding surface in a limited time. It has been shown that the sliding mode control problem for the Markovian jump systems is solvable if a set of coupled LMIs have solutions. A numerical example is given to show the potential of the proposed techniques.
Large peridotite massifs are scattered along the 1500km length of the Yarlung-Zangbo Suture Zone (southern Tibet, China), the major suture between Asia and Greater India. Diamonds occur in the ...peridotites and chromitites of several massifs, together with an extensive suite of trace phases that indicate extremely low fO sub(2) (SiC, nitrides, carbides, native elements) and/or ultrahigh pressures (UHP) (diamond, TiO sub(2) II, coesite, possible stishovite). New physical and isotopic (C, N) studies of the diamonds indicate that they are natural, crystallized in a disequilibrium, high-T environment, and spent only a short time at mantle temperatures before exhumation and cooling. These constraints are difficult to reconcile with previous models for the history of the diamond-bearing rocks. Possible evidence for metamorphism in or near the upper part of the Transition Zone includes the following: (1) chromite (in disseminated, nodular and massive chromitites) containing exsolved pyroxenes and coesite, suggesting inversion from a high-P polymorph of chromite; (2) microstructural studies suggesting that the chromitites recrystallized from fine-grained, highly deformed mixtures of wadsleyite and an octahedral polymorph of chromite; (3) a new cubic Mg-silicate, with the space group of ringwoodite but an inverse-spinel structure (all Si in octahedral coordination); (4) harzburgites with coarsely vermicular symplectites of opx + Cr-Al spinel plus or minus cpx; reconstructions suggest that these are the breakdown products of majoritic garnets, with estimated minimum pressures to>13GPa. Evidence for a shallow pre-metamorphic origin for the chromitites and peridotites includes the following: (1) trace-element data showing that the chromitites are typical of suprasubduction-zone (SSZ) chromitites formed by magma mixing or mingling, consistent with Hf-isotope data from magmatic (375Ma) zircons in the chromitites; (2) the composition of the new cubic Mg-silicate, which suggests a low-P origin as antigorite, subsequently dehydrated; (3) the peridotites themselves, which carry the trace element signature of metasomatism in an SSZ environment, a signature that must have been imposed before the incorporation of the UHP and low-fO sub(2) phases. A proposed P-T-t path involves the original formation of chromitites in mantle-wedge harzburgites, subduction of these harzburgites at c. 375Ma, residence in the upper Transition Zone for >200 Myr, and rapid exhumation at c. 170-150Ma or 130-120Ma. Os-isotope data suggest that the subducted mantle consisted of previously depleted subcontinental lithosphere, dragged down by a subducting oceanic slab. Thermomechanical modeling shows that roll-back of a (much later) subducting slab would produce a high-velocity channelized upwelling that could exhume the buoyant harzburgites (and their chromitites) from the Transition Zone in<10 Myr. This rapid upwelling, which may explain some characteristics of the diamonds, appears to have brought some massifs to the surface in forearc or back-arc basins, where they provided a basement for oceanic crust. This model can reconcile many apparently contradictory petrological and geological datasets. It also defines an important, previously unrecognized geodynamic process that may have operated along other large suture zones such as the Urals.
The cancer stem cell hypothesis suggests that neoplastic clones are maintained exclusively by a small subpopulation of cells, which have indefinite proliferation and differentiation potentials and ...give rise to phenotypically diverse cancer cells. Cancer stem cells have been isolated by their ability to efflux Hoechst 33342 dye and are referred to as the 'side population' (SP).
The Hoechst efflux assay was used to isolate and characterize the SP from murine D121 lung carcinoma cells. Here, we demonstrated that D121-SP cells contain cancer stem cell characteristics, that is, upregulation of the transcription factors SOX2 and Oct 4 in D121-SP cells. In addition, the migration of D121-SP was decreased, and apoptosis of D121-SP was upregulated following knocking down of SOX2 in D121 cells. Importantly, downregulation of SOX2 in D121 cells markedly suppressed their metastatic potential in syngeneic mice.
These results suggest that the SP is an enriched source of lung tumour cells with stem cell properties and that SOX2 has an important role in maintaining stem cell properties and functions that may be a potential target for effective lung cancer therapy.
Salt-sensitivity is associated with a more severe target organ injury and higher mortality, even in normotensive subjects. As endothelial dysfunction is predictive for future cardiovascular events, ...we evaluated whether normotensive salt-sensitive (NSS) subjects have more pronounced endothelial dysfunction compared with normotensive salt-resistant (NSR) subjects. Normotensive subjects (n=99, aged 25-50 years) were selected from a rural community in northern China. Salt sensitivity was assigned if mean BP increased by ≥10% from a 1-week high salt (18 g/day, NaCl) to low-salt diet (3 g/day, NaCl). Endothelial function was assessed by testing the flow-mediated dilatation (FMD) of the brachial artery using high-resolution ultrasound, as well as nitrogen oxide (NOx) levels, in plasma and urine at baseline. Blood pressure at baseline was similar between NSS and NSR subjects, but diverged during salt intervention. Furthermore, FMD was significantly lower in 17 NSS subjects (10.2±2.5 vs 14.5±1.6%, P=0.037) compared with NSR subjects. In addition, average plasma NOx levels were lower in NSS subjects than NSR subjects (61.2±3.23 μM vs 82.5±1.61 μM, P=0.034). Moreover, Both FMD and plasma NOx levels were negatively correlated with the degree of salt sensitivity (r=-0.435 and r=-0.459, respectively, P<0.01). However, there was no difference in urine NOx between the two groups. Our study indicates that endothelial dysfunction could contribute to the long-term higher levels of target organ injury and higher mortality observed in NSS subjects.
Based on data samples collected with the BESIII detector at the BEPCII collider, the process e^{+}e^{-}→Σ^{+}Σover ¯^{-} is studied at center-of-mass energies sqrts=2.3960, 2.6454, and 2.9000 GeV. ...Using a fully differential angular description of the final state particles, both the relative magnitude and phase information of the Σ^{+} electromagnetic form factors in the timelike region are extracted. The relative phase between the electric and magnetic form factors is determined to be sinΔΦ=-0.67±0.29(stat)±0.18(syst) at sqrts=2.3960 GeV, ΔΦ=55°±19°(stat)±14°(syst) at sqrts=2.6454 GeV, and 78°±22°(stat)±9°(syst) at sqrts=2.9000 GeV. For the first time, the phase of the hyperon electromagnetic form factors is explored in a wide range of four-momentum transfer. The evolution of the phase along with four-momentum transfer is an important input for understanding its asymptotic behavior and the dynamics of baryons.
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