A space hurricane over the Earth's polar ionosphere.

In Earth's low atmosphere, hurricanes are destructive due to their great size, strong spiral winds with shears, and intense rain/precipitation. However, disturbances resembling hurricanes have not been detected in Earth's upper atmosphere. Here, we report a long-lasting space hurricane in the polar ionosphere and magnetosphere during low solar and otherwise low geomagnetic activity. This hurricane shows strong circular horizontal plasma flow with shears, a nearly zero-flow center, and a coincident cyclone-shaped aurora caused by strong electron precipitation associated with intense upward magnetic field-aligned currents. Near the center, precipitating electrons were substantially accelerated to ~10 keV. The hurricane imparted large energy and momentum deposition into the ionosphere despite otherwise extremely quiet conditions. The observations and simulations reveal that the space hurricane is generated by steady high-latitude lobe magnetic reconnection and current continuity during a several hour period of northward interplanetary magnetic field and very low solar wind density and speed.

Multiple transpolar auroral arcs reveal insight about coupling processes in the Earth's magnetotail.

A distinct class of aurora, called transpolar auroral arc (TPA) (in some cases called "theta" aurora), appears in the extremely high-latitude ionosphere of the Earth when interplanetary magnetic field (IMF) is northward. The formation and evolution of TPA offers clues about processes transferring energy and momentum from the solar wind to the magnetosphere and ionosphere during a northward IMF. However, their formation mechanisms remain poorly understood and controversial. We report a mechanism identified from multiple-instrument observations of unusually bright, multiple TPAs and simulations from a high-resolution three-dimensional (3D) global MagnetoHydroDynamics (MHD) model. The observations and simulations show an excellent agreement and reveal that these multiple TPAs are generated by precipitating energetic magnetospheric electrons within field-aligned current (FAC) sheets. These FAC sheets are generated by multiple-flow shear sheets in both the magnetospheric boundary produced by Kelvin-Helmholtz instability between supersonic solar wind flow and magnetosphere plasma, and the plasma sheet generated by the interactions between the enhanced earthward plasma flows from the distant tail (less than -100 RE) and the enhanced tailward flows from the near tail (about -20 RE). The study offers insight into the complex solar wind-magnetosphere-ionosphere coupling processes under a northward IMF condition, and it challenges existing paradigms of the dynamics of the Earth's magnetosphere.

Clinical features and related risk factors of sleep hypopnea in obstructive sleep apnea hypoventilation syndrome / 天津医药

Objective To analyze the clinical features and related risk factors of sleep hypopnea (SH) in obstructive sleep apnea hypoventilation syndrome (OSAHS). Methods A total of 63 patients with OSAHS who were underwent polysomnography (PSG) and transcutaneous carbon dioxide partial pressure (TCPCO2) monitoring were selected in this study. All patients were divided into pure OSAHS group (n=35) and OSAHS with SH group (n=28) according to the diagnostic criteria of SH. The clinical features of nocturnal carbon dioxide and related risk factors were compared between two groups, including gender, age, complications, body mass index (BMI), Epworth sleepiness scale (ESS), micro awakening index, arterial blood gas analysis, PSG and TCPCO2. Correlation analysis were used to analyze the correlation between the highest TCPCO2 and other variables. The influencing factors of the highest TCPCO2 were analyzed by multiple linear regression analysis. Receiver operating characteristic (ROC) curve analysis was used to analyze the value for related variables in the diagnosis of SH. Results Twenty-eight patients were diagnosed as SH in all the 63 patients with OSAHS, the proportion was 44.4%. There were no significant differences in gender, age and smoking proportion between the two groups. Data of BMI, arterial carbon dioxide partial pressure [p(CO2)], prevalence of hypertension, ESS, apnea hypopnea index, micro arousal index, percentage of nighttime sleep with blood oxygen saturation less than 90%, highest TCPCO2 and TCPCO2 during each sleep stage were significantly higher in the OSAHS with SH group than those in the pure OSAHS group (P<0.05), while arterial oxygen partial pressure [p(O2)] and the lowest pulse oxygen saturation (SpO2) were significantly lower than those in pure OSAHS group (P<0.05). The highest TCPCO2 was positively correlated with p(CO2), ESS and BMI (P<0.01). Multiple linear regression analysis showed that the highest TCPCO2 was affected by BMI and ESS. As a possible predictor for OSAHS with SH, BMI>31.43 kg/m2 showed a sensitivity of 64.3%and specificity of 91.4%, and ESS score>12 showed a sensitivity of 78.6%and specificity of 71.4%. Conclusion The patients of OSAHS with SH have more severe nocturnal hypercapnia and hypoxemia. OSHAS patients are recommend to undergo TcPCO2 monitoring, when BMI is greater than 31.43 kg/m2 and ESS is greater than 12 scores.

[Study of IR Property of Glow Discharge Polymer (GDP)].

To achieve the object of NIF ignition , it is required to prepare high density fuel targets . For DD layer, IR-layering can be used to improve its surface roughness. In this paper, glow discharge polymer (GDP) flat films and capsules were synthesized. The IR absorptive properties of GDP were thoroughly studied by using infrared spectrometer and microscopy while the extinction coefficients of GDP flat film at specific wavelengths were obtained. By comparing absorption properties of flat films and capsules, it is found that thermal treatments can lower the OH content of GDP and thus improve IR layering of DD ice. Finally, the needed IR power of integration sphere were estimated by using data obtained for future DD layering experiments in this paper. The results have laid a solid foundation for the implementation of DD IR layering.

Solar wind origin in coronal funnels.

The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by various ions with the force-free magnetic field as extrapolated from photospheric magnetograms to different altitudes. Specifically, we find that Ne7+ ions mostly radiate around 20 megameters, where they have outflow speeds of about 10 kilometers per second, whereas C3+ ions with no average flow speed mainly radiate around 5 megameters. Based on these results, a model for understanding the solar wind origin is suggested.