EASYFLOW: Keep Ethereum Away From Overflow

While Ethereum smart contracts enabled a wide range of blockchain applications, they are extremely vulnerable to different forms of security attacks. Due to the fact that transactions to smart contracts commonly involve cryptocurrency transfer, any successful attacks can lead to money loss or even financial disorder. In this paper, we focus on the overflow attacks in Ethereum , mainly because they widely rooted in many smart contracts and comparatively easy to exploit. We have developed EASYFLOW , an overflow detector at Ethereum Virtual Machine level. The key insight behind EASYFLOW is a taint analysis based tracking technique to analyze the propagation of involved taints. Specifically, EASYFLOW can not only divide smart contracts into safe contracts, manifested overflows, well-protected overflows and potential overflows, but also automatically generate transactions to trigger potential overflows. In our preliminary evaluation, EASYFLOW managed to find potentially vulnerable Ethereum contracts with little runtime overhead.Comment: Proceedings of the 41st International Conference on Software Engineering: Companion Proceedings. IEEE Press, 201

Chemical composition of Dipsacus asper Wallich ex Candolle (Dipsacaceae) essential oil and its activity against mosquito larvae of Aedes aegypti and Culex pipiens pallens

Purpose: To evaluate the larvicidal activity of the essential oil of Dipsacus asper Wallich ex Candolle (Dipsacaceae) roots against the larvae of Aedes aegypti L. and Culex pipiens pallens Coquillett.Methods: Essential oil was extracted from D. asper roots by hydrodistillation and analyzed for its composition by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The oil was evaluated for larvicidal activity, using World Health Organization (WHO) procedures, against the fourth larvae of A. aegypti and C. pipiens pallens within 24 h, and activity was recorded for various concentrations of the oil ranging from 12.5 – 200.0 μg/mL.Results: A total of 34 components of the essential oil of D. asper were identified. The major compounds of the essential oil were caryophyllene oxide (13.29 %), caryophyllene (9.14 %), cubebene (7.87 %), β-gurjunene (6.43 %), carvone (5.38 %), 1,8-cineole (5.29 %), and calamenene (5.05 %). The oil exhibited larvicidal activity against A. aegypti and C. pipiens pallens at median lethal concentrations (LC50) of 56.29 μg/mL and 47.49 μg/mL, respectively.Conclusion: The essential oil of D. asper roots has potentials for use in the control of A. aegypti and C. pipiens pallens and may be useful in the search for new, safer and more effective natural larvicides.Keywords: Dipsacus asper, Aedes aegypti, Culex pipiens pallens, Essential oil, Larvicidal activity, Caryophyllene, Cubebene, β-Gurjunene, Carvon

Understanding the e+e−→D(∗)+D(∗)−e^+e^-\to D^{(*)+}D^{(*)-} processes observed by Belle

We calculate the production cross sections for $D^{*+}D^{*-}$, $D^+D^{*-}$ and $D^+D^-$ in $e^+e^-$ annihilation through one virtual photon in the framework of perturbative QCD with constituent quarks. The calculated cross sections for $D^{*+}D^{*-}$ and $D^+D^{*-}$ production are roughly in agreement with the recent Belle data. The helicity decomposition for $D^{*}$ meson production is also calculated. The fraction of the $D^{*\pm}_LD^{*\mp}_T$ final state in $e^+e^-\to D^{*+}D^{*-}$ process is found to be 65%. The fraction of $DD^*_T$ production is 100% and $DD^*_L$ is forbidden in $e^+e^-$ annihilation through one virtual photon. We further consider $e^+e^-$ annihilation through two virtual photons, and then find the fraction of $DD^{*}_T$ in $e^+e^-\to DD^{*}$ process to be about 91%.Comment: 8 pages, 2 figure

Chemical Composition of Zanthoxylum avicennae Essential Oil and its Larvicidal Activity on Aedes albopictus Skuse

Purpose: To determine the larvicidal activity of the essential oil derived from Zanthoxylum avicennae (Lam.) DC. (Rutaceae) leaves and stems against the larvae of Aedes albopictus Skuse．Methods: Essential oil of Z. avicennae leaves and stems were obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mas spectrometry (GC-MS). The activity of the essential oil was evaluated, using World Health Organization (WHO) procedures, against the fourth larvae of A. albopictus for 24 h and larval mortality recorded at various essential oil concentrations ranging from 12.5 - 200 μg/mL.Results: A total of 31 components of the essential oil of Z. avicennae were identified. The essential oil had higher content of monoterpenoids (65.70 %) than sesquiterpenoids (33.45 %). The principal compounds of the essential oil were 1,8-cineol (53.05 %), β-elemene (6.13 %), α-caryophyllene (5.96%), β-caryophyllene (5.09 %) and caryophyllene oxide (4.59 %). The essential oil exhibited larvicidal activity against A. albopictus with a median lethal concentration (LC50) value of 48.79 μg/mL.Conclusion: The findings obtained indicate that the essential oil of Z. avicennae has potentials for use in the control of A. albopictus larvae and could be useful in the search for newer, safer and more effective natural compounds as larvicides.Keywords: Aedes albopictus, Essential oil, Larvicidal activity, Mosquito, Zanthoxylum avicenna

The swimming behavior of the aquatic larva of Neoneuromus ignobilis (Megaloptera: Corydalidae: Corydalinae).

In order to explore the pattern and significance of swimming, through photos and videos we observed and recorded the swimming behavior of the aquatic larvae of Megaloptera in detail for the first time using the endemic Chinese species Neoneuromus ignobilis Navas, 1932 as the test insect, which were collected from the Dadu River and reared in nature-simulated environments. Four swimming postures are recognized and described herein in detail, i. e., vertical, parallel, back and side swimming, and these postures were used by the larvae disproportionately, with a frequency of 89.08%, 5. 49%, 4. 40% and 0. 61% , respectively. The swimming larvae tend to pose their body into an S-shape, with various degree of sinuation. By changing the directions of the head and tail, they can easily rise up or sink and change swimming postures. The propulsion was generated by the wriggling of the body while the legs were mostly held close to the body. Larvae of different instars varied greatly in swimming ability, the 6th ins tar larvae being the best and most active swimmer compared to the 2nd and final instars. The larvae may also employ complex defense behaviors not often known from relatively ancient insect groups, like chemical defense as secretion from the end of abdomen

In-situ cosmogenic ³⁶Cl denudation rates of carbonates in Guizhou karst area

This study quantifies surface denudation of carbonate rocks by the first application of in-situ cosmogenic <sup>36</sup>Cl in China. Concentrations of natural Cl and in-situ cosmogenic <sup>36</sup>Cl in bare carbonates from Guizhou karst areas were measured with isotope dilution by accelerator mass spectrometer. The Cl concentration varied from 16 to 206 ppm. The <sup>36</sup>Cl concentrations were in range of (0.8–2.4)×106 atom g−1, resulting in total denudation rates of 20–50 mm ka−1 that averaged over a 104–105 a timescale. The <sup>36</sup>Cl-denudation rates showed roughly a negative correlation with the local mean temperature. This preliminary observation may suggest the variations of proportions of chemical weathering and physical erosion in denudation process, depending upon local climatic conditions