We present optical observations of an SN 2002cx-like supernova SN 2013en in UGC 11369, spanning from a phase near maximum light (t = + 1 d) to t = + 60 d with respect to the R-band maximum. Adopting ...a distance modulus of μ = 34.11 ± 0.15 mag and a total extinction (host galaxy+Milky Way) of A
V ≈ 1.5 mag, we found that SN 2013en peaked at MR
≈ −18.6 mag, which is underluminous compared to the normal SNe Ia. The near maximum spectra show lines of Si ii, Fe ii, Fe iii, Cr ii, Ca ii and other intermediate-mass and iron group elements which all have lower expansion velocities (i.e. ∼ 6000 km s− 1). The photometric and spectroscopic evolution of SN 2013en is remarkably similar to those of SN 2002cx and SN 2005hk, suggesting that they are likely to be generated from a similar progenitor scenario or explosion mechanism.
The process e+e- → Λ Λ ¯ is studied using data samples at √s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. The Born cross section is ...measured at √s=2.2324 GeV, which is 1.0 MeV above the Λ Λ ¯ mass threshold, to be 305±$45_{-36}^{+66}$ pb, where the first uncertainty is statistical and the second systematic. The substantial cross section near threshold is significantly larger than that expected from theory, which predicts the cross section to vanish at threshold. The Born cross sections at √s=2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with improved precision. Finally, the corresponding effective electromagnetic form factors of Λ are deduced.
Abstract Objectives Many studies have shown that insomnia is a common problem among university students, but there are wide variations in the prevalence of insomnia. In this systematic review, we ...aimed to explore the prevalence of insomnia among university students using scientific and conclusive methods. Study design A systematic review is designed to analyze the studies reporting on prevalence of insomnia among university students. Methods Systemic searches were conducted in PubMed, BioMed Central, EBSCO, ScienceDirect, Ovid LWW and Medline databases between January 2000 and July 2014, The Meta analyst software was used to calculate the prevalence rate of each study, the pooled means of prevalence rates and 95% CIs across studies were then calculated and presented. Results Seven articles that met the inclusion and exclusion criteria were selected. The overall sample size in the current review was 16,478, with a minimum of 219 and a maximum of 10,322. The prevalence rates of the seven studies ranged between 9.4% (95%CI 8.8–10.0%) and 38.2% (95% CI 35.4–41.1%). Overall, the total students studied with a weighted mean prevalence of 18.5% (95% CI 11.2–28.8%), considerably higher than rates of 7.4% (95% CI 5.8–9.0%) reported in general population. Conclusions This review emphasized that insomnia prevalence in university students is considerably higher than that in general population, suggested that more attention should be paid to insomnia in university students.
Background
Dopamine (DA) is a negative modulator of gut motility. Monoamine oxidase‐B (MAO‐B) is an important metabolic enzyme degrading DA. Rasagiline, an irreversible MAO‐B inhibitor, is used to ...treat Parkinson’s disease because of its neuroprotective effect and increasing central DA. However, it is unclear whether MAO‐B exists in the colon and rasagiline increases colonic DA, thereby affecting colonic motility.
Methods
Immunohistochemistry, western blotting, enzyme activity assay, colonic motility recording, gut transit test, and high‐performance liquid chromatography‐electrochemical detection were employed in this study.
Key Results
Monoamine oxidase‐B was distributed in the colonic muscular layers including neurons and glias of rat and human. When oral treatment of rats with rasagiline for 4 weeks, in vitro colonic motility was significantly reduced, but it was greatly reversed by SCH‐23390, an antagonist of DA D1 receptor. The rasagiline‐treated rats also manifested decreased MAO‐B activity and increased DA content in the colonic muscular layer, but no alterations were detected in the protein expressions of D1 and D2 receptors, and MAO‐A and MAO‐B, as well as in the content of 5‐hydroxytryptamine and noradrenaline. Moreover, acute administration of rasagiline did not affect the colonic motility in vitro and the colonic DA level in rats, although MAO‐B activity was significantly inhibited.
Conclusions & Inferences
Monoamine oxidase‐B is abundant in the colonic muscular layer including myenteric plexus of rat and human. Long‐term administration of rasagiline can increase colonic DA thereby inhibiting colonic motility, suggesting that colonic MAO‐B could be a potential drug target for colonic dysmotility.
Monoamine oxidase‐B was distributed in the colonic muscular layers including neurons and glias of rat and human. Long‐term treatment of rasagiline significantly inhibited colonic monoamine oxidase‐B activity and increased the dopamine content, which may contribute to colonic hypomotility.
In addition to a bulk energy gap, topological insulators accommodate a conducting, linearly dispersed Dirac surface state. This state is predicted to become massive if time reversal symmetry is ...broken, and to become insulating if the Fermi energy is positioned inside both the surface and bulk gaps. We introduced magnetic dopants into the three-dimensional topological insulator dibismuth triselenide (Bi₂Se₃) to break the time reversal symmetry and further position the Fermi energy inside the gaps by simultaneous magnetic and charge doping. The resulting insulating massive Dirac fermion state, which we observed by angle-resolved photoemission, paves the way for studying a range of topological phenomena relevant to both condensed matter and particle physics.
In order to study the temporal and spatial variations of PM2.5 and its chemical compositions in the region of Beijing, Tianjin, and Hebei (BTH), PM2.5 samples were collected at four urban sites in ...Beijing (BJ), Tianjin (TJ), Shijiazhuang (SJZ), and Chengde (CD), and also one site at Shangdianzi (SDZ) regional background station over four seasons from 2009 to 2010. The samples were weighted for mass concentrations and analyzed in the laboratory for chemical profiles of 19 elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Pb, Sr, Ti, V, and Zn), eight water-soluble inorganic ions (Na+ , NH4+ , K+ , Mg2+ , Ca2+ , Cl- , NO3- , and SO42- , and carbon fractions (OC and EC). The concentrations of PM2.5 and its major chemical species were season dependent and showed spatially similar characteristics in the plain area of BTH. The average annual concentrations of PM2.5 were 71.8-191.2 μg m-3 at the five sites, with more than 90% of sampling days exceeding 50 μg m-3 at BJ, TJ, and SJZ. PM2.5 pollution was most serious at SJZ, and the annual concentrations of PM2.5 , secondary inorganic ions, OC, EC, and most crustal elements were all highest. Due to stronger photochemical oxidation, the sum of concentrations of secondary inorganic ions (NH4+ , NO3- , and SO42- was highest in the summer at SDZ, BJ, TJ, and CD. Analysis of electric charges of water-soluble inorganic ions indicated the existence of nitric acid or hydrochloric acid in PM2.5 . For all five sites, the concentrations of OC, EC and also secondary organic carbon (SOC) in the spring and summer were lower than those in the autumn and winter. SOC had more percentages of increase than primary organic carbon (POC) during the winter. The sums of crustal elements (Al, Ca, Fe, Mg, Ti, Ba, and Sr) were higher in the spring and autumn owing to more days with blowing or floating dust. The concentrations of heavy metals were at higher levels in the BTH area by comparison with other studies. In Shijiazhuang and Chengde, the PM2.5 pollution was dominated by coal combustion. Motor vehicle exhausts and coal combustion emissions both played important roles in Tianjin PM2.5 pollution. However, motor vehicle exhausts had played a more important role in Beijing owing to the reduction of coal consumption and sharp increase of cars in recent years. At SDZ, regional transportation of air pollutants from southern urban areas was significant.
•MnCo2O4 nanowire array is prepared by a fast and facile hydrothermal method.•MnCo2O4 nanowire array exhibits noticeable pseudocapacitive properties.•The as-prepared nanowire array is also a ...promising material for Li-ion batteries.
One-dimension MnCo2O4 nanowire arrays are synthesized on nickel foam by a facile hydrothermal method. The MnCo2O4 nanowires are highly crystalline with an average diameter of 70nm and exhibit excellent properties for electrochemical energy storage. Impressively, the MnCo2O4 nanowire array exhibits noticeable pseudocapacitive performance with a high capacitance of 349.8 F g−1 at 1 A g−1 and 328.9 F g−1 at 20 A g−1 as well as excellent cycling stability. As an anode material for Li-ion batteries, the MnCo2O4 nanowire array delivers an initial specific discharge capacity of 1288.6 mAh g−1 at 100mAg−1, with reversible capacity retention of 92.7% after 50 cycles. The outstanding electrochemical performances are mainly attributed to its nanowire array architecture which provides large reaction surface area, fast ion and electron transfer and good structure stability.
We study the process e^{+}e^{-}→Λ_{c}^{+}Λover ¯_{c}^{-} at twelve center-of-mass energies from 4.6119 to 4.9509 GeV using data samples collected by the BESIII detector at the BEPCII collider. The ...Born cross sections and effective form factors (|G_{eff}|) are determined with unprecedented precision after combining the single and double-tag methods based on the decay process Λ_{c}^{+}→pK^{-}π^{+}. Flat cross sections around 4.63 GeV are obtained and no indication of the resonant structure Y(4630), as reported by Belle, is found. In addition, no oscillatory behavior is discerned in the |G_{eff}| energy dependence of Λ_{c}^{+}, in contrast to what is seen for the proton and neutron cases. Analyzing the cross section together with the polar-angle distribution of the Λ_{c}^{+} baryon at each energy point, the moduli of electric and magnetic form factors (|G_{E}| and |G_{M}|) are extracted and separated. For the first time, the energy dependence of the form factor ratio |G_{E}/G_{M}| is observed, which can be well described by an oscillatory function.
PDF
