The sopite syndrome revisited: drowsiness and mood changes during real or apparent motion

The sopite syndrome is a poorly understood response to motion. Drowsiness and mood changes are the primary characteristics of the syndrome. The sopite syndrome can exist in isolation from more apparent symptoms such as nausea, can last long after nausea has subsided, and can debilitate some individuals. It is most likely a distinct syndrome from "regular" motion sickness or common fatigue, and is of potential concern in a variety of situations. The syndrome may be particularly hazardous in transportation settings where other performance challenges (e.g., sleep deprivation) are already present. It is also a potential concern in cases where illnesses such as sleep disorders or depression may interact with the syndrome and confuse diagnosis.     

Effect of parametric and nonlinear perturbations on statistical dynamics of the Earth’s pole

We study the influence of additive and parametric slowly varying harmonic (at the Chandler frequency and doubled frequency) and stochastic Gaussian broadband perturbations on mathematical expectations, variances, and covariations of oscillations of the Earth’s pole. The influence of perturbations on both regular and irregular stochastic oscillations is considered in detail. Results of numerical experiments are presented. The developed models and software are included into information resources on the fundamental problem “Statistical dynamics of the Earth’s rotation” of Russian Academy of Sciences.     

Effect of microgravity on Escherichia coli and MS-2 bacteriophage disinfection by iodinated resins

Experiments on chemical disinfection by iodinated resins were conducted on STS 50 (USML-1), which flew a 13 day mission during 1992. Fluid processing apparatus containing microorganisms and iodinated resins was assembled in either Manhattan, Kansas, or Boulder, Colorado, and loaded on-board the Space Shuttle for the mission. Pentaiodide resin was more effective than the triiodide resin against Escherichia coli. Both resins were more effective bactericides at unit gravity than microgravity because of cosedimentation of bacteria and iodinated resin beads. In bacteriophage experiments, the triiodide resin reduced the viable titer of MS-2 by nine logs. The few viable phage surviving chemical disinfection were associated with precipitant formation in the fluid processing apparatus.     

Recovery of lower limb function following 6 weeks of non-weight bearing

Skeletal muscle weakness and atrophy occur following an extended period of decreased use, including space flight and limb unloading. It is also likely that affected muscles will be susceptible to a re-loading injury when they begin return to earth or weight bearing. However, there is a paucity of literature evaluating the response of human unloaded muscle to exercise and return to activity.

The purpose of this pilot study was to evaluate the soreness, function and strength response of muscle to re-loading in seven patients who were non-weight bearing for 6 weeks, compared to five healthy subjects.

Function improved significantly over time for the patients but was still less than the healthy subjects over 12 weeks of physiotherapy. Concentric quadriceps muscle strength increased significantly over time for the patients. There was considerable variability in the patients’ reports of muscle soreness but there were no significant changes over time or between groups.     

Observations of diffuse galactic positron annihilation radiation

The Galactic plane was scanned nearly three times by the UCSD/MIT Hard X-Ray and Low Energy Gamma-Ray Experiment on HEAO-1 from August 1977 through September 1978. Its Medium Energy Detectors were of the NaI/CsI phoswich type and operated over the 100 keV to 2 MeV range, with a 17° FWHM field of view and a 9% energy resolution at 511 keV. Sky maps for each epoch of observation were constructed in several energy bands. After subtraction of known point sources, a component associated with the galactic plane remains, whose spectrum is consistent with a power law and a positron annihilation spectrum. In the 333 to 583 keV energy band the flux is concentrated within ±35° of the galactic center, and the ratio of flux/radian (anticenter) is high, with a 2σ lower limit of 13. The parameters of the galactic center region's annihilation spectrum are positronium fraction of 0.9±0.1 and 511 keV flux of (2.0±0.7)×10⁻³ photons/cm²-sec-rad.     

TC-1和Geotail对亚暴过程中近地等离子体片磁扰动的联合观测

以2004年9月28日02:53:20 UT的亚暴为例, 通过TC-1在磁尾约12.5 R_e 和Geotail卫星在近地磁尾等离子体片约8～9 R_e的联合观测, 研究亚暴触发过程中近地磁尾等离子体片中等离子体波动特征. 结果表明, 亚暴触发区是近地磁尾中心等离子体片中较小的一个区域, 在亚暴触发区中低混杂不稳定性在近地磁尾等离子体片中存在, 准垂直传播的低混杂波发生在亚暴触发过程中, 而亚暴触发过程中近地磁尾等离子体片外边界区内的磁场偶极化信号和扰动都非常微弱. 在亚暴触发和亚暴膨胀相过程中出现了多次具有不同特征的磁场偶极化现象.     

Aspartic acid racemization and age-depth relationships for organic carbon in Siberian permafrost

We have analyzed the degree of racemization of aspartic acid in permafrost samples from Northern Siberia, an area from which microorganisms of apparent ages up to a few million years have previously been isolated and cultured. We find that the extent of aspartic acid racemization in permafrost cores increases very slowly up to an age of approximately 25,000 years (around 5 m in depth). The apparent temperature of racemization over the age range of 0-25,000 years, determined using measured aspartic acid racemization rate constants, is -19 degrees C. This apparent racemization temperature is significantly lower than the measured environmental temperature (-11 to -13 degrees C) and suggests active recycling of D-aspartic acid in Siberian permafrost up to an age of around 25,000 years. This indicates that permafrost organisms are capable of repairing some molecular damage incurred while in a "dormant" state over geologic time.     

长征运载火箭飞行过程中二级游机提前或推迟关机问题的探讨

论述了具有小推力飞行段的长征运载火箭在飞行过程中二级游机提前或推迟关机的机理,明确给出了游机可能提前或推迟关机的时间范围,为以后的火箭飞行参数判定提供理论依据。     

The team ROC curve in a binary hypothesis testing environment

We consider the distributed detection problem, in which a set of decision makers (DMs) receive observations of the environment and transmit finite-valued messages to other DMs according to prespecified communication protocols. A designated primary DM makes the find decision on one out of two alternative hypotheses. All DMs make decisions, in order to maximize a measure of organizational performance. We discuss three different types of decision rules (deterministic, independent randomization, and dependent randomization), and their implications on the organizational performance. Each DM is described by its individual receiver operating characteristic (ROC) curve, which is concave. We determine that concavity is not guaranteed for the case of the ROC curve of a team of DMs, even if the decision rules are perfectly continuous and if the individual ROC curves are strictly concave and smooth unless dependent randomization is allowed