Mating compatibility between bactrocera invadens and bactrocera dorsalis (Diptera: Tephritidae)

The invasive fruit fly, Bactrocera invadens Drew, Tsuruta & White, is a highly polyphagous fruit pest that occurs predominantly in Africa yet has its origins in the Indian subcontinent. It is extremely morphologically and genetically similar to the Oriental fruit fly, Bactrocera dorsalis (Hendel); as such the specific relationship between these two species is unresolved. We assessed prezygotic compatibility between B. dorsalis and B. invadens using standardized field cage mating tests, which have proven effectiveness in tephritid cryptic species studies. These tests were followed by an assessment of postzygotic compatibility by examining egg viability, larval and pupal survival, and sex ratios of offspring produced from parental and subsequent F1 crosses to examine for hybrid breakdown as predicted under a two-species hypothesis. B. dorsalis was sourced from two countries (Pakistan and China), and each population was compared with B. invadens from its type locality of Kenya. B. invadens mated randomly with B. dorsalis from both localities, and there were generally high levels of hybrid viability and survival resulting from parental and F1 crosses. Furthermore, all but one hybrid cross resulted in equal sex ratios, with the single deviation in favor of males and contrary to expectations under Haldane's rule. These data support the hypothesis that B. dorsalis and B. invadens represent the same biological species, an outcome that poses significant implications for pest management and international trade for sub-Saharan Africa.

Behavior of pretilachlor and dimethametryn in water of flooded rice fields

In order to understand the behavior of pretilachlor, a popular rice herbicide in the world, and a synergetic active ingredient, dimethametryn, a monitoring study was conducted in 3 paddy plots in Kyushu region, Japan. The monitoring indicated different behaviors for both pesticides from those reported in the literature. Maximum concentrations of pretilachlor and dimethametryn were 1 order of magnitude lower than the values observed in previous studies. However, the dissipation rates estimated from monitoring data were in agreement with other studies in Japan. The pesticide product was tested and showed good dissolution of pretilachlor and dimethametryn in water, suggesting that another study is needed to explain the low concentrations of the two pesticides in the fields. Besides pesticide behaviors, it was observed from the monitoring that water management in paddy rice cultivation still requires more attention to reduce the environmental risk of rice pesticides.

Comparative analysis of traffic state estimation ─ Cumulative counts-based and trajectory-based methods

The Macroscopic Fundamental Diagram (MFD) relates space-mean density and flow. Since the MFD represents the area-wide network traffic performance, studies on perimeter control strategies and network-wide traffic state estimation utilising the MFD concept have been reported. Most previous works have utilised data from fixed sensors, such as inductive loops, to estimate the MFD, which can cause biased estimation in urban networks due to queue spillovers at intersections. To overcome the limitation, recent literature reports the use of trajectory data obtained from probe vehicles. However, these studies have been conducted using simulated datasets; limited works have discussed the limitations of real datasets and their impact on the variable estimation. This study compares two methods for estimating traffic state variables of signalised arterial sections: a method based on cumulative vehicle counts (CUPRITE), and one based on vehicles’ trajectory from taxi Global Positioning System (GPS) log. The comparisons reveal some characteristics of taxi trajectory data available in Brisbane, Australia. The current trajectory data have limitations in quantity (i.e., the penetration rate), due to which the traffic state variables tend to be underestimated. Nevertheless, the trajectory-based method successfully captures the features of traffic states, which suggests that the trajectories from taxis can be a good estimator for the network-wide traffic states.

Analyzing hysteresis behavior of capacitance-voltage characteristics of IZO/C₆₀/pentacene/Au diodes with a hole-transport electron-blocking polyterpenol layer by electric-field-induced optical second-harmonic generation measurement

By using electric-field-induced optical second-harmonic generation (EFISHG) measurement, we analyzed hysteresis behavior of capacitance-voltage (C-V) characteristics of IZO/polyterpenol (PT)/C₆₀/pentacene/Au diodes, where PT layer is actively working as a hole-transport electron-blocking layer. The EFISHG measurement verified the presence of interface accumulated charges in the diodes, and showed that a space charge electric field from accumulated excess electrons (holes) that remain at the PT/C₆₀ (C₆₀/pentacene) interface is responsible for the hysteresis loop observed in the C-V characteristics.

Impact resistance and evaluation of retained strength on geotextiles

Over the last few decades, geotextiles have progressively been incorporated into geotechnical applications, especially in the field of coastal engineering. Geotextile materials often act as separator and a filter layer between rocks laid above and subgrade beneath. This versatile material has gradually substituted traditional granular materials because of its ease of installation, consistent quality and labour costefficiency. However, geotextiles often suffer damage during installation due to high dynamic bulk loading of rock placement. This can degrade geotextiles' mechanical strength. The properties considered in this paper include the impact resistance and retained strength of geotextiles. In general, the greater the impact energy applied to geotextiles, the greater the potential for damage. Results highlight the inadequacy of using index derived values as an indicator to determine geotextile performance on site because test results shows that geotextiles (staple fibre (SF) and continuous filament (CF)) with better mechanical properties did not outperform lower mechanical strength materials. The toughest CF product with a CBR index value of 9696N shows inferior impact resistance compared to SF product with the least CBR strength (2719N) given the same impact energy of 9.02 kJ. Test results also indicated that the reduction of strength for CF materials were much greater (between 20 and 50%) compared to SF materials (between 0 and 5%) when subjected to the same impact energy of 4.52 kJ.