358 research outputs found
A cusp catastrophe model of mid–long-term landslide evolution over low latitude highlands of China
AbstractBased on a model describing a certain landslide case and catastrophe theory, we derived a cusp catastrophe model and corresponding inversion method to study mid–long-term landslide evolution. According to data of landslides, precipitation, and socioeconomic development from 1976 to 2008, the cusp catastrophe model describing this landslide evolution across a low-latitude highland area in China is obtained with the least squares method. Results of the model indicate that human activity determines landslide intensity. Local precipitation also impacts yearly landslide intensity to some extent, and controls the time when a strong and abrupt change in landslides occurs. During the period 1976–2008, there was an abrupt decrease of landslide intensity during 1994–1995, and an abrupt increase during 1995–1996. Since then, there have been frequent landslides in the low-latitude highland, with greater intensity. All these factors provide a scientific basis for formulating a contingency plan regarding landslide disasters
Electronic and Transport Properties of Radially Deformed Double-walled Carbon Nanotube Intramolecular Junction
The electronic and transport property of a radially deformed double-walled
carbon nanotube (DWNT) intramolecular junction (IMJ) has been studied by the
tight-binding (TB) model combined with the first-principle calculations. The
geometrical structures of the DWNT IMJ have been first optimized in energy by
the universal force field (UFF) method. It is found that when heavily squashed,
the DWNT will become an insulator-coated metallic wire, and the conductance
near the Fermi level has been significantly changed by the radial squash.
Specially, several resonance conductance peaks appear at some energies in the
conduction band of the squashed DWNT IMJ. Finally, we have also investigated
the conductance variation due to change of the length of the central
semiconductor in the squashed DWNT IMJ. Furthermore, a promising pure carbon
nanoscale electronic device is proposed based on the DWNT IMJ.Comment: 11 pages, 4 figure
The Non-Linear Influence of Built Environment on the School Commuting Metro Ridership: The Case in Wuhan, China
Although many studies have investigated the non-linear relationship between the built environment and rail patronage, it remains unclear whether this influence is equally applicable to primary and secondary school students due to their physiological characteristics and cognitive limitations. This study applies the GBDT model to Wuhan student metro swipe data in order to investigate the relative importance and non-linear association of the built environment on the school-commuting metro ridership. The results show that the variable with the greatest predictive power is the number of living service facilities followed by the number of intersections, and the degree of land-use mixture. All of the built environment variables had non-linear associations with the school-commuting ridership, and the greatest attraction to the school-commuting metro ridership occurred when the number of living service facilities was 500, the number of intersections was 36, and the degree of land-use mixture was 0.8. These findings can help planners to prioritize land-use optimization and the effective range of land-use indicators when developing child-friendly rail transport policies
The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2
On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth
asteroid 4179 Toutatis at a closest distance of 770 120 meters from the
asteroid's surface. The highest-resolution image, with a resolution of better
than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at
the big end, a sharply perpendicular silhouette near the neck region, and
direct evidence of boulders and regolith, which suggests that Toutatis may bear
a rubble-pile structure. Toutatis' maximum physical length and width are (4.75
1.95 km) 10, respectively, and the direction of the + axis
is estimated to be (2505, 635) with respect to the
J2000 ecliptic coordinate system. The bifurcated configuration is indicative of
a contact binary origin for Toutatis, which is composed of two lobes (head and
body). Chang'e-2 observations have significantly improved our understanding of
the characteristics, formation, and evolution of asteroids in general.Comment: 21 pages, 3 figures, 1 tabl
Interleukin-22 inhibits respiratory syncytial virus production by blocking virus-mediated subversion of cellular autophagy
Respiratory syncytial virus (RSV) infection can cause severe bronchiolitis in infants requiring hospitalization, whereas the elderly and immunocompromised are prone to RSV-induced pneumonia. RSV primarily infects lung epithelial cells. Given that no vaccine against RSV is currently available, we tested the ability of the epithelial-barrier protective cytokine interleukin-22 (IL-22) to control RSV production. When used in a therapeutic modality, IL-22 efficiently blunted RSV production from infected human airway and alveolar epithelial cells and IL-22 administration drastically reduced virus titer in the lungs of infected newborn mice. RSV infection resulted in increased expression of LC3B, a key component of the cellular autophagic machinery, and knockdown of LC3B ablated virus production. RSV subverted LC3B with evidence of co-localization and caused a significant reduction in autophagic flux, both reversed by IL-22 treatment. Our findings inform a previously unrecognized anti-viral effect of IL-22 that can be harnessed to prevent RSV-induced severe respiratory disease
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