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Wildfire is an important disturbance factor in forest ecosystem and could affect the distribution of insects. Because Monochamus beetles are known vector insects of pine wood nematodes in Korea and burnt pine trees can be used as oviposition habitats for Monochamus beetles, we investigated changes in the spatial (among fire severity classes) and temporal (between years) distributions of M. alternatus and M. saltuarius. From late May 2017 to early October 2018, four multi-funnel traps with pheromone lure were installed in each fire severity class (unburned, light, light-moderate edge, moderate-severe edge, and severe). All traps were replaced fortnightly from May to October for two years. The spatial distribution of the two Monochamus beetles was significantly affected by fire severity. In particular, M. alternatus showed higher catches in the severely burned sites and responded positively to the fire. A similar number of M. saltuarius individuals were observed between 2017 and 2018, while more M. alternatus were caught in 2018 compared to 2017. Consequently, it was confirmed that the dead wood of P. densiflora caused by the wildfire had a great influence on the density of insects, especially M. alternatus.

Pine wilt disease (PWD) is one of the most destructive diseases affecting pine trees, and South Korea is one of the most severely damaged countries in the world. Based on the information on PWD occurrence and their environmental characteristics (i.e., geographical, meteorological, and land-use) in South Korea, we evaluated the conditions most conducive for PWD occurrence and developed projection models using machine learning algorithms; random forest (RF) and maximum entropy (Maxent). Our results showed that PWD mainly occurred in areas like highly urbanized area; low elevations, at close proximity to roads. Also, both RF and Maxent models presented high prediction performance for PWD occurrence. Geographical factors (e.g., elevation and distance to roads) were major determinants of PWD occurrence and largely contributed to explaining variability and partial dependence plots of each model. We developed an ensemble model composed of the RF and Maxent models to predict a potential risk map for PWD occurrence on a national scale. In South Korea, most territory was included potential risk of PWD occurrence, and it was predicted to be expanded in the future according to the climate change. The study results showed a high utility for use in surveillance and monitoring of PWD occurrence by inferring the spread pathway or spread direction of PWD based on the potential occurrence map.

Plodia interpunctella is a globally important insect pest that infests stored food products. Infestation may cause a substantial increase in economic costs for pest control and entails quality loss and dissatisfaction of consumers. The aim of this study was to predict the potential distribution of P. interpunctella feeding on four different diets (rice bran, vegetables, wheat bran, or walnuts) using a CLIMEX model and provide basic data for the storage and management of processed food products. To estimate the CLIMEX parameter of P. interpunctella feeding on rice bran, the developmental rate at different temperatures was tested, resulting in a lower developmental threshold and the degree days of 12.5 °C and 461 DD, respectively. In the spatial analysis, the climatic suitability of P. interpunctella feeding on rice bran was the highest when compared to other diets and particularly higher than that of walnuts in 23.3% of the total area. Our results are expected to provide basic data for the management of P. interpunctella based on species distribution modeling, which, in our study, produced different predicted distribution patterns based on diet and climate.

Oak wilt disease caused by a symbiotic fungus of ambrosia beetles is a serious problem in oak forest in Asian countries, with the potential to become a great threat to oak forests worldwide. In this study, we developed a control method, consisting of collection devices attached directly to infested host trees, for mass trapping of emerging ambrosia beetles. Effectiveness of the device was evaluated in terms of the retention fluid used in collection bottles, and the position of the bottles along the host trunk. A total of 87,081 ambrosia beetles were captured from 23 oak trees (Quercus mongolica). More beetles were captured in collection bottles installed at low positions of oak stems, compared to collection bottles located at the middle and upper positions (30, 90, 150 cm above ground). We analyzed the effect of ethanol and water on beetle capture, determining that bottle position was more important than the contents of the collection bottle. There was no statistical difference between catches with ethanol vs water. There was a positive relationship between host DBH (diameter at breast height) and the number of captured beetles. Our mass trapping device proved to be very effective for capturing emerging ambrosia beetles from damaged oak trees in field tests. This new device could be useful in managing the population of ambrosia beetles, and has the potential to reduce the spread of oak wilt disease in oak forests.

This study examined the effects of environmental factors on the abundance of black pine bast scale (BPBS), Matsucoccus thunbergianae Miller and Park, in coastal disaster prevention pine forests. Geographical factors, soil conditions and forest stand conditions were measured to evaluate the hazard rating for the occurrence of BPBS at 35 plots in the coastal forest stands. A combination of a self-organizing map (SOM), which classified the samples according to their characteristics, and a random forest model, which predicted the probability of the BPBS occurrence from SOM results, were used to assess the hazard rating. Our results showed that climate, tree size, and tree health are major factors determining the abundance of BPBS. BPBS was more common in low latitude coastal forests, suggesting that warmer conditions were favorable to BPBS population buildup. Tree size also influenced the abundance of BPBS, which was higher in forests composed of larger trees (greater DBH). Finally, BPBS was also more abundant in areas with high soil salinity and clay-loam soil, and north-facing slopes where tree vigor was lower. These results can provide useful information for improved coastal pine forests management against BPBS.

The diurnal flight pattern of Platypus koryoensis (Murayama) was examined using sticky traps attached to the trunks of oak trees in central Korea in 2010 and 2011. The flight activities of the beetle were estimated on the basis of 3-h intervals for trap catches from 11:00 to 14:00 on the next day, on June 25–26 and July 1–2, 2010, and on the basis of 2-h intervals for trap catches from 5:00 to 17:00, between June 9 and July 21, 2011 (the peak flight period of the beetle). Over 77% of the beetles were caught from 9:00 to 13:00, with the daily variations in the facing slope. The beetles began to be caught when the air temperature reached around 16 °C, and were the most active when the temperature ranged from 20 to 27 °C. No beetles were caught during rainfall, suggesting that rainfall is one of the factors that hinder beetle flight. The beetles were caught by traps in the east-facing plot earlier than those in the south- and west-facing plots suggesting that the flight behavior of the beetle can be affected by the light. Direction of the beetle flight during the peak of daily flight (from 09:00 to 13:00) was downward along the slope.

We measured the Aharonov-Bohm (AB) effect in graphene rings with superconducting-(Al) and normal-metal (Au) mirrors. The mirrors were deposited either on additional stubs connected to the rings in the transverse direction or on the ring bias lines. A significant enhancement of the visible phase coherence was observed in the latter case, in which we observed even the third harmonic of the AB oscillations. The superconductivity of the mirrors appears to be unimportant for the improved coherence in graphene. A large Fermi energy mismatch between graphene and the mirror material is sufficient for this effect. In addition, a transport gap was observed in our graphene structures at the gate voltage close to the Dirac point. The value of the gap can be reproduced by assuming the occurrence of Coulomb blockade effects in graphene.

Graphene structures with both top- and bottom-electrostatic gates are studied. The top gate is made of thin aluminium (Al) film deposited directly onto graphene, with no prior dielectric layer in between. Natural oxidation of Al at the interface with graphene results in an insulating barrier proving useful in making top gates to graphene. For electrically disconnected top gate, graphene resistance as a function of the slowly-varying back-gate voltage shows hysteresis which reveals dielectric properties of the barrier. The estimated barrier thickness is only 2 nm allowing for very sharp profiles of the electric field in graphene devices. By applying voltages to both back- and top gates, effective p–n–p junctions with sharp interfaces can be created.

In this study, we determined the effect of controlling rice weevils on the mycoflora of stored brown rice by using Anisopteromalus calandrae (Howard), a parasite of the rice weevil. The mycoflora in brown rice with the parasitoid was similar to that without the parasitoid; however, the dominant mold species differed. Without the parasitoid, Aspergillus candidus Link and Penicillium islandicum Sopp were the dominant species, whereas Aspergillus penicilloides Speg. and P. islandicum were dominant when the parasitoid was present. The difference appeared to be due mainly to the difference in the grain moisture content with and without the parasitoid. A. candidus was the dominant species in the communities without the parasitoid and was not observed when the weevils were suppressed. P. islandicum dominated or co-dominated regardless of the presence of the parasitoid which suggested that P. islandicum is tolerant to low grain moisture content or is positively affected by the presence of the rice weevil.

We present results of non-linear magneto resistance (MR) of polyacetylene nanofibers in high magnetic field up to H = 30 T at low temperature T = 1.5 K. The MR was proven to be of the spin origin; it reaches 16% at highest H . Unexpectedly, the MR was suppressed by increasing electric field E , vanishing at E ≳ 5 × 10 4 V/cm. It is understood that the doping induced spinless charged soliton pairs, which are initially confined to a certain distance because of the interchain phase correlations, and are deconfined in high electric fields, resulting in a vanishing magneto resistance (VMR). The role of the specific, degenerate ground state of the polyacetylene is confirmed by parallel studies of the different magneto resistances of polyaniline nanofibers which contrarily is not affected by the electric field.

We have investigated the temperature dependence of electrical conductivity and thermoelectric power (TEP) at 1.7 K T 2+ chelate. We observed intrinsic metallic temperature dependence of resistivity from room temperature to 68 K with a broad minimum [ ρ (68 K)/ ρ (300 K) ∼0.75], which has not been observed previously in similar organo metallic complexes. There occurs an unusual metal-insulator transition at T ∼68 K and the resisitivity increases upon cooling below 68 K. However, the low temperature resistivity becomes finite (instead of going to infinity), [ρ(1.7 K)/ ρ (300 K) ∼0.98] indicating that a quantum mechanical tunneling conduction is dominant at this low temperature. It is remarkable that the resistivity at 1.7 K is as small as that of room temperature. Such unusual temperature dependence of conductivity could be understood as thermally assisted hopping conduction between metallic islands. However, the observed intrinsic metallic temperature dependence of resistivity implies that such hopping conduction barrier is not important at high temperature ( T > 68 K). The intrinsic metallic characteristics are confirmed by the quasi-linear temperature dependence of TEP for the whole measured temperature range (1.7 K T T

The ability of Bracon hebetor Say, a larval parasitoid of certain stored product moths, to suppress a Plodia interpunctella (Hlibner) population was studied in differing rice products. The larvae of P. interpunctella gathered on the topmost layer of the experiment cages filled with rice product (less than 3 cm in depth), and were rarely observed in deeper depths (deeper than 3 cm). Without P. interpunctella, B. he-etor did not show a preference for any of the three types of milled rice products used. In rice flour, the searching behavior of B. hebetor for P. interpunctella was limited, apparently due to the thick webbing pro-uced by the moth larvae. B. hebetor suppressed P. interpunctella population successfully in cracked rice kernels, but failed to suppress the moth population in rice flour. In whole rice kernels, B. hebetor suppressed the moth population only when the volume of rice in the cage was large enough to support a high population density of P. interpunctella (2.4 kg/cage). Success and failure of B. hebetor to suppress the moth population in the three different rice products are discussed in relation to the larval webbing and intraspecific com-etition of P. interpunctella larvae.