[1] It has been suggested that drift loss to the magnetopause can be one of the major loss mechanisms contributing to relativistic electron flux dropouts. In this study, we examine details of relativistic electrons' drift physics to determine the extent to which the drift loss through the magnetopause is important to the total loss of the outer radiation belt. We have numerically computed drift paths of relativistic electrons' guiding center for various pitch angles, various measurement positions, and different solar wind conditions using the Tsyganenko T02 model. We specifically demonstrate how the drift loss effect depends on these various parameters. Most importantly, we present various estimates of relative changes of the omnidirectional flux of 1 MeV electrons between two different solar wind conditions based on a simple form of the directional flux function. For a change of the dynamic pressure from 4 nPa to 10 nPa with a fixed IMF B Z = 0 nT, our estimate indicates that after this increase in pressure, the equatorial omnidirectional flux at midnight near geosynchronous altitude decreases by $56 to $97%, depending on the specific pitch angle dependence of the directional flux. The effect rapidly decreases at regions earthward of geosynchronous orbit and shows a general trend of decrease away from midnight. For a change of the IMF B Z from 0 nT to À15 nT with a fixed dynamic pressure of 4 nPa, the relative decrease of the omnidirectional flux at geosynchronous altitude on the nightside is much smaller than that for the pressure increase, but its effect becomes substantial only beyond geosynchronous orbit. Possibilities exist that our results may change to some extent for a different magnetospheric model than the one used here.

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When a drop is deposited on a superhydrophilic micropillar array, the upper part of the drop (referred to as the bulk) collapses while the bottom part penetrates into the gaps of the array, forming a fringe film. Here we quantify the early stage dynamics of this process using a combination of experiment and theory. We show that the circular front of the fringe film spreads like t1/2, t being time, when coupled to the bulk flow. However, the film is found to advance like t1/3 through faceted zippering in the absence of the bulk. We then show that the spreading of the bulk and the entire drop footprint follows a power law (t1/4) that is different from Washburn's law. This work can be a starting point to completely understand the spreading of liquids on superhydrophilic surfaces and opens questions specific to superwetting behaviour including the criteria to determine whether the fringe film will expand through lateral zipping or advance radially outwards.

Background: Conflicting results have been reported concerning the progression of medial meniscal extrusion (MME) after arthroscopic transtibial pull-out repair of medial meniscus posterior root tear (MMRT), and no study has evaluated the relevant factors affecting the progression of MME. Purpose: To (1) evaluate the subjective and objective surgical outcomes of arthroscopic transtibial pull-out repair of MMRT and (2) identify relevant factors affecting the progression of MME after surgery. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 63 patients who underwent isolated arthroscopic transtibial pull-out repair of MMRT between January 2010 and June 2017 were evaluated retrospectively. Clinical scores and various radiographic parameters were evaluated to assess the surgical outcomes. The patients were classified into 2 groups according to the change in medial meniscal extrusion ratio (MMER) at 1 year after surgery compared with before surgery (group 1 consisted of 21 patients with reduced or maintained MMER; group 2 consisted of 42 patients with increased MMER). Variables including baseline demographics, radiographic parameters, and arthroscopic findings were compared to identify relevant factors affecting the progression of MME after surgery. Results: In the overall cohort, clinical outcomes at postoperative 2 years improved significantly ( P < .001 for visual analog scale score, International Knee Documentation Committee subjective score, and Lysholm score), whereas radiographic parameters showed an overall deterioration compared with the preoperative level. In subgroup comparisons, a significant difference was seen in the time from the onset of symptoms until surgery ( P < .001), defined as preoperative symptom duration, which a subsequent logistic regression analysis revealed to be a relevant factor associated with the progression of MMER ( P = .015). Both groups showed progression of radiographic osteoarthritis, but the progression was significantly higher in group 2 compared with group 1 at postoperative 2 years ( P = .032). On receiver operating characteristic curve analysis, the cutoff point for preoperative symptom duration associated with the progression of MMER was 13 weeks (sensitivity, 52.4%; specificity, 76.2%; accuracy, 72.4%). Conclusion: The arthroscopic transtibial pull-out repair of MMRT showed clinical improvement but did not prevent the progression of knee osteoarthritis, MME, or MMER. Although the preservation of MMER was not capable of completely preventing the progression of knee degeneration, MMER still has a potential clinical value in delaying the rate of progression of knee degeneration. Early surgical repair of MMRT, within 13 weeks from the onset of symptoms, might be helpful to prevent the progression of MME.

Accurate knowledge of the global distribution of plasmaspheric hiss is essential for the radiation belt modeling because it provides a direct link to understanding the radiation belt loss in the slot region. In this paper, we study the dependence of hiss activity on solar wind parameters and geomagnetic activity indices using Time History of Events and Macroscale Interactions during Substorms hiss measurements made from 1 July 2008 to 30 June 2012 based on a correlation analysis. We find that hiss amplitudes are well correlated with the preceding solar wind speed V SW , interplanetary magnetic field (IMF) B Z , and interplanetary electric field (IEF) E Y with delay times of 5-6 h for V SW and 3-4 h for IMF B Z and IEF E Y , while the best correlation with the geomagnetic indices, AE, Kp, and SYM-H, occurs at a delay time of 2-3 h for AE and SYM-H and 3-4 h for Kp. Of the solar wind parameters, the dawn-to-dusk component of IEF E Y yields the best correlation with the variation of hiss wave. More interestingly, the global distribution of hiss waves shows a significant dependence on the V SW and IMF B Z : the most intense hiss region tends to occur at prenoon sector for a more southward IMF B Z , while the tendency is opposite with increasing V SW . This implies different origins of hiss activity. Also, we employ an artificial neural network technique to develop models of the global distribution of hiss amplitudes based on the solar wind parameters and geomagnetic indices. The solely solar wind parameter-based model generally results in a higher correlation between the measured and modeled hiss amplitudes than any other models based on the geomagnetic indices. Finally, we use the solar wind parameter-based model to investigate hiss activity during storm events by distinguishing between coronal mass ejection-driven storms and corotating interaction region-driven storms. The result shows that in spite of the differences in the behavior of solar wind parameters between the two storm groups, the different types of storms lead to the similar evolution of hiss waves in overall appearance even though the detailed behavior of hiss activations are different.