Meridional Transport in the Stratosphere of Jupiter

The Cassini measurements of C$_2$H$_2$ and C$_2$H$_6$ at $\sim$5 mbar provide a constraint on meridional transport in the stratosphere of Jupiter. We performed a two-dimensional photochemical calculation coupled with mass transport due to vertical and meridional mixing. The modeled profile of C$_2$H$_2$ at latitudes less than 70$^\circ$ follows the latitude dependence of the solar insolation, while that of C$_2$H$_6$ shows little latitude dependence, consistent with the measurements. In general, our model study suggests that the meridional transport timescale above 5-10 mbar altitude level is $\gtrsim$1000 years and the time could be as short as 10 years below 10 mbar level, in order to fit the Cassini measurements. The derived meridional transport timescale above the 5 mbar level is a hundred times longer than that obtained from the spreading of gas-phase molecules deposited after the impact of Shoemaker-Levy 9 comet. There is no explanation at this time for this discrepancy.Comment: 11 pages, 3 figures, 1 table. ApJL in pres

Short-period solar cycle signals in the ionosphere observed by FORMOSAT-3/COSMIC

We analyze 2 years of the FORMOSAT-3/COSMIC GPS radio occultation data to study the response of the Earth's ionosphere to the solar rotation (27-day) induced solar flux variations. Here we report electron density variations in the ionosphere (∼100–500 km) associated with the 27-day solar cycle. The peak-to-peak variation in electron density at low latitudes in the F2 region is about ∼10^4–10^5 electrons cm^(−3) or 20–40%, and can be as high as 60% depending on altitude, latitude, and season. The half and double periods of the 27-day are also observed at an amplitude comparable to that of the 27-day. The results place useful constraints for modeling chemical and dynamical processes in the ionosphere

Robustness Verification Method for Artificial Intelligence Systems Based on Source Code Processing

The development of artificial intelligence (AI) technology provides strong support for AI systems based on source code processing. Compared with natural language processing, source code is special in semantic space. Machine learning tasks related to source code processing usually employ abstract syntax trees, data dependency graphs, and control flow graphs to obtain the structured information of codes and extract features. Existing studies can obtain excellent results in experimental scenarios through in-depth analysis of source code structures and flexible application of classifiers. However, for real application scenarios where the source code structures are more complex, most of the AI systems related to source code processing have poor performance and are difficult to implement in the industry, which triggers practitioners to consider the robustness of AI systems. As AI-based systems are generally data-driven black box systems, it is difficult to directly measure the robustness of these software systems. With the emerging adversarial attack techniques, some scholars in natural language processing have designed adversarial attacks for different tasks to verify the robustness of models and conducted large-scale empirical studies. To solve the instability of AI systems based on source code processing in complex code scenarios, this study proposes robustness verification by Metropolis-Hastings attack method (RVMHM). Firstly, the code preprocessing tool based on abstract syntax trees is adopted to extract the variable pool of the model, and then the MHM source code attack algorithm is employed to replace the prediction effect of the variable perturbation model. The robustness of AI systems is measured by observing the changes in the robustness verification index before and after the attack by interfering with the data and model interaction process. With vulnerability prediction as a typical binary classification scenario of source code processing, this study verifies the robustness of 12 groups of AI vulnerability prediction models on three datasets of open source projects to illustrate the RVMHM effectiveness for robustness verification of source code processing based on AI systems

A preliminary study on the key factors contributing to the attractive lips of Chinese children

AbstractObjectiveTo explore the aesthetic characteristics of the Chinese children lips.MethodsFrontal and profile photographs of 653 healthy children were categorized as the attractive and the unattractive by three laypersons and objectively measured for comparison.ResultsThe attractive group tended to be smaller in the upper paramedian red lip height, the lower paramedian red lip height, the midline upper red lip height, the central bow angle, and the lip angle, while greater in the Cupid's bow width.ConclusionsThinner lips seemed to be more attractive than full ones among Chinese children

Toxicities comparison of rotenone and acetone extract of Tephrosiavogelii and Derris trifoliate against Solenopsis invicta

The high rotenone content and the rotenone crude extract of Tephrosia vogelii and Derris trifoliata were evaluated for its efficacy in the control of red imported fire (RIFA), Solenopsis invicta under both laboratory and field conditions. The acetone extracts of D. trifoliata roots and T. vogelii leaves exhibited strong toxicity to macroergate and micrergate of RIFA. When active ingredients of the crude extracts were convert to rotenone, the activity of the acetone extracts were higher than that of rotenone technical material. At the same time, the extracts showed significant inhibitory effect on walking ability and grasping ability of worker ants and stronger than the effect of 98.6% rotenone technical material. Under field conditions, the 0.01% rotenone-bait, formulated with the acetone extract of D. trifoliata roots and T. vogelii leaves, had the same control effect on RIFA as that of 0.01% fipronil-bait when treated after 30 d. The bait formulated with the extract of D. trifoliata exhibited quicker and higher effect on RIFA than that of rotenone technical material. It was showed that the acetone extracts of D. trifoliata roots and T. vogelii leaves are able to control S. invicta under both laboratory and field conditions and can be used as an effective agent against RIFA

Euphorbia factor L8: a diterpenoid from the seeds of Euphorbia lathyris

The title compound [systematic name: (2S*,3S*,4R*,5R*,9S*,11S*,15R*)-5,15-diacet­oxy-3-nicotino­yloxy-14-oxolathyra-6(17),12(E)-diene], C30H37NO7, was isolated from the seeds of Euphorbia lathyris. The tricyclic diterpenoid molecule contains an 11-membered ring, a five-membered ring exhibiting an envelope conformation and a three-membered ring. The 11-membered ring is cis-fused with the three-membered ring and trans-fused with the five-membered ring

Simulation of upper tropospheric CO₂ from chemistry and transport models

The California Institute of Technology/Jet Propulsion Laboratory two-dimensional (2-D), three-dimensional (3-D) GEOS-Chem, and 3-D MOZART-2 chemistry and transport models (CTMs), driven respectively by NCEP2, GEOS-4, and NCEP1 reanalysis data, have been used to simulate upper tropospheric CO2 from 2000 to 2004. Model results of CO2 mixing ratios agree well with monthly mean aircraft observations at altitudes between 8 and 13 km (Matsueda et al., 2002) in the tropics. The upper tropospheric CO2 seasonal cycle phases are well captured by the CTMs. Model results have smaller seasonal cycle amplitudes in the Southern Hemisphere compared with those in the Northern Hemisphere, which are consistent with the aircraft data. Some discrepancies are evident between the model and aircraft data in the midlatitudes, where models tend to underestimate the amplitude of CO2 seasonal cycle. Comparison of the simulated vertical profiles of CO2 between the different models reveals that the convection in the 3-D models is likely too weak in boreal winter and spring. Model sensitivity studies suggest that convection mass flux is important for the correct simulation of upper tropospheric CO2

CO_2 in the upper troposphere: Influence of stratosphere-troposphere exchange

A two-dimensional transport model constrained to measured surface CO_2 concentrations was used to simulate the spatial and temporal variation of CO_2 in the atmosphere for the period from 1975 to 2004. We find that the amplitude, phase and shape of the CO_2 seasonal cycle vary as a function of both altitude and latitude. Cross tropopause exchanges, especially the downward branch of the Brewer-Dobson circulation, which brings stratospheric air to the upper troposphere at middle and high latitudes, change the CO_2 concentration and seasonal cycle in the extra-tropics. The model results match recent aircraft measurements of CO_2 in the upper troposphere (Matsueda et al., 2002) remarkably well. We conclude that upper tropospheric CO_2 volume mixing ratios will provide a valuable tool for validating vertical transport. The implications of the CO_2 variation caused by the stratosphere-troposphere exchange for remote sensing of CO_2 are discussed