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Solid state beam steering devices are key elements in low cost, robust, and three-dimensional imaging systems. Here, we present a silicon photonic beam steering device based upon an 8 × 8 grating coupler focal plane array approach fed by a thermo-optic Mach–Zehnder switching tree. In this device, transmission of light from the grating couplers is made through the backside of the chip using topside mirrors allowing for both high-efficiency out-coupling and direct flip-chip integration of drive electronics, providing a path to scale to denser focal plane arrays with large numbers of points in the future. A −13.8 dB fiber-to-fiber transmission was achieved in our preliminary test around 1523 nm for the beam steering chip.

The development of low-thermal-budget Ge-on-Si epitaxial growth for the fabrication of low-cost Ge-on-Si devices is highly desirable for the field of silicon photonics. At present, most Ge-on-Si growth techniques require high growth temperatures, followed by cyclic annealing at temperatures > 800°C, often for a period of several hours. Here, we present a low-temperature (400°C) low-cost plasma-enhanced chemical vapor deposition (PECVD) Ge-on-Si growth study and, subsequently, fabricate a high-speed zero-bias 12.5-Gb/s waveguide integrated photodetector with a responsivity of 0.1 A/W at a wavelength of 1550 nm. This low-energy device demonstrates the feasibility of the PECVD method for the fabrication of low-cost low-thermal-budget Ge-on-Si devices.

Abstract Plants can be attacked by a wide variety of herbivores. Thus, developing protective mechanisms for resistance against these agents is an advantage for survival and reproduction. Over the course of evolution, many resistance mechanisms against herbivory have been developed by the plants. Induced direct and indirect resistance mechanisms can manifest in plants after herbivore attack. The two-spotted spider mite Tetranychus urticae is not a pest of maize crops (Zea mays), despite being reported infesting plants that may have resistances against this herbivore. We tested the hypothesis that maize plants would be able to induce direct resistance against T. urticae after, evaluating the effect of T. urticae infestation in maize plants on the development and reproduction of conspecifics. We tested induced direct resistance performing infestation and measuring biological parameters upon a second infestation. Maize plants, 40 days after sowing, were divided into two groups: 30 not infested by T. urticae (clean plants clean) and, 30 infested by the spider mite. Infestation of maize plants by T. urticae reduced the conspecific female adult survival. However, no change in the survival of immature or reproduction was observed. These results suggest the induction of induced direct resistances in maize by T. urticae. This is first report of direct resistance induction in Z. mays by the two-spotted spider mite T. urticae.

Earthquake-triggered landslides have drawn much attention around the world because of the severe hazards they pose. The 20 April 2013 Ms = 7.0 Lushan Earthquake, which occurred in the Longmen Shan region in Sichuan province, China, triggered more than 1000 landslides throughout an area of about 2200 km2, and completely blocked many roads and exacerbated overall transportation problems in the mountainous terrain. Preliminary landslide inventory is complied immediately following the earthquake, mainly based on the high-resolution remote sensing images. At the same time, the distribution of these landslides is statistically investigated to determine how the occurrence of landslides correlates with distance from the earthquake epicenter, slope steepness, seismic intensity and rock type. Statistic analysis is conducted using landslide point density (LPD), which is defined as the number of landslides per square kilometer. It is found that LPD has a strong positive correlation with slope gradients and a negative-exponential decline with the distance from the epicenter. The higher LPD values occur in younger strata systems like Quaternary and Tertiary sediments in the study area. Spatially, the triggered landslides are controlled by the causative faults and mainly concentrated around the epicenter. All the landslides are located within the area with seismic intensity ≥ VII and in line with seismic intensity. Generally, LPD value decreases with increasing distance from the epicenter, and sometimes landslides are densely distributed along the roads in the mountainous region. Also, this study reveals that the empirical relationship between distance and seismic magnitude is more suitable for estimating the landslide concentration area during the Lushan earthquake compared to other methods.