No abstract

Cosmogenic 10 Be surface-exposure dating and numerical glacier modeling are used to reconstruct glacial chronology and climate in the Colorado Sangre de Cristo Mountains during the local last glacial maximum (LLGM) and the subsequent deglaciation. Twenty-two surface-exposure ages on moraine boulders and polishedbedrock outcrops in the Willow Creek valley and ten in two adjacent valleys indicate that glaciers were at or near their maxima from ~21ka until 17-16 ka, and then retreated rapidly, nearly deglaciating the Willow Creek valley entirely by ~14 ka. Coupled energy/mass-balance and flow modeling of two of the glaciers indicates that, if changing ice extent was driven only by temperature and insolation changes, temperature depressions of 5.0 and 5.1°C from modern conditions, with an uncertainty ofapproximately +1.5 −1.0°C , would have sustained the glaciers in massbalance equilibrium at their LLGM extents. Doubling or halving of modern precipitation during the LLGM would have been associated with 2.7-3.0°C and 6.9-7.0°C temperature depression respectively. Approximately half of the subsequent LLGM-to-modern climate change was accomplished by ~14 ka. If the rapid main phase of deglaciation betweenabout 16 kaand 14 ka was driven solely by temperature and insolation changes, it would have been associated with a temperature rise of about 2.5°C, at a mean rate of approximately 1.1°C/ky. This new chronology of the last glaciation is generally consistent with others developed recently in the Colorado Rocky Mountains. The numerical modeling, 2 however,suggests a lesserLLGM temperature depression from modern conditions than have most previous studies in Colorado.

The Chinese citrus fly, Bactrocera minax (Enderlein) (Diptera: Tephritidae), is the most destructive citrus pest in many citrus production areas in China. The pest is oligophagous, feeding exclusively on the fruits of citrus plants. The pest is univoltine, with adults emerging during April to May and overwintering as pupae. Evidence suggests that the region of origin of the species might be in the elevated temperate southern Yunnan-Guizhou Plateau, spreading out through China's major waterway systems. Currently, B. minax occurs in nine citrus producing provinces in China, but mostly prominently in the five south central provinces or municipalities of Guizhou, Hubei, Hunan, Sichuan, and Chongqing. Fruit infestations in these provinces are generally moderate to severe. The species is not reported in the four southern citrus production provinces of Guangdong, Fujian, Zhejiang, and Hainan (island). Orchard sanitation such as collection and treatment of the fallen and hanging infested fruits, mass trapping by using various food-based traps with insecticides, and foliar and ground insecticide sprays are the primary pest management options. Sterile insect technology was studied in the field in the 1980s to 1990s, with promising outcomes. The two highly attractive kairomone lures used for many Bactrocera species, cuelure or methyl eugenol, are not attractive to this species. Hydrolyzed protein, sugar and vinegar mixture, and waste brewer's yeast are the most common lures being used in China. Published data indicated that the quality and efficacy of these lures are inconsistent and disputable. Visual cue lures such as colored sticky spheres are also being used in the field. Preliminary field studies suggested that female rectum extracts demonstrated high attraction to males as well as females of the species. Phytosanitary treatment studies in China focus on irradiation and cold treatment. The outcomes of irradiation appeared promising. When B. minax larvae were treated with an irradiation dose of 50 Gy, no adults emerged from the surviving pupae and larvae failed to pupate when the dose reached 70 Gy. No fruit quality was impacted by the treatment. Results from several small-scale cold treatment studies were less promising and inconsistent. One study indicated that under 0˚C constant treatment, no mortality of 3rd instar larvae occurred until day 12, and only 55% mortality occurred by day 22. The scientific and technological gaps in safeguarding US citrus industry from the invasion of this destructive pest include: 1) lack of effective lures for early detection and emergency responses; 2) insufficient work on phytosanitary treatment techniques; and 3) weak definition of and lack of data for B. minax pest free areas in China.

A many-body dissipative particle dynamics model, namely, MDPD, is applied for simulation of pore-scale, multi-component, multi-phase fluid flows in fine-grained, nanoporous shales. Since this model is able to simultaneously capture the discrete features of fluid molecules in nanometer size pores and continuum fluid dynamics in larger pores, and is relatively easy to parameterize, it has been recognized as being particularly suitable for simulating complex fluid flow in multi-length-scale nanopore networks of shales. A remarkable feature of this work is the integration of a high-resolution FIB-SEM (focused ion beam scanning electron microscopy) digital imaging technique to the MDPD model for providing 3D voxel data that contain the invaluable geometrical and compositional information of shale samples. This is the first time that FIB-SEM is seamlessly linked to a Lagrangian model like MDPD for fluid flow simulation, which offers a robust approach to bridging gaps between the molecular- and continuum-scales, since the relevant spatial and temporal scales are too big for molecular dynamics, and too small for computational fluid dynamics with known constitutive models. Simulations ranging from a number of benchmark problems to a forced two-fluid flow in a Woodford shale sample are presented. Results indicate that this model can be used to deliver reasonable simulations for multi-component, multi-phase fluid flows in arbitrarily complex pore networks in shales.

On the basis of the density functional theory coupled with the Boltzmann transport equation with relaxation time approximation, we investigate the electronic structure and predict the electron mobility of few-layer InSe. Few-layer InSe has a tunable band gap on thickness. At the same time, it possesses a high carrier mobility on the order of 103 cm2 V−1 s−1. As we demonstrated, few-layer InSe has potential applications for next-generation electronic materials owing to its considerable band gap and high carrier mobility.