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An outbreak of downy mildew disease of onion, caused by Peronospora destructor, in Japan in 2016 necessitated a reevaluation of the primary inoculum sources to optimize disease management. Detection of the P. destructor pathogen in plants with asymptomatic infection and in soil would guide the application of fungicides according to the extent of infection before disease development. Here, we detected P. destructor in both plants and soil using newly developed primer sets (Pd ITS and Pd ITS 614) by both conventional and real-time PCR. Validation by real-time PCR with Pd ITS 614 showed that P. destructor DNA was amplified from symptomless seedlings at 3.7 × 102 to 1.0 × 100 conidium cells/50 mg leaf tissue, suggesting the detection of asymptomatic infection. Real-time PCR with Pd ITS amplified pathogen DNA from field soils at 1.6 × 103 to 8.3 × 101 oospore cells/g of soil. This real-time PCR assay provides a useful tool for identifying and quantifying inoculum sources, which may be the foundation of the design of integrated disease management strategies.

An outbreak of downy mildew disease of onion, caused by

Lettuce big-vein disease, caused by Mirafiori lettuce big-vein virus and Lettuce big-vein associated virus, is suppressed when the pH of field soil becomes acidic. Therefore, we evaluated the effect of soil pH on the activities of Olpidium virulentus, the vector of the viruses. We found that acidic soil, pH less than 6.0, significantly reduced O. virulentus infection of the root and influenced the detection rate of zoospores released in the surrounding water. We concluded that acidic soil suppresses zoospore release from zoosporangia.

In this paper, we study the topological properties of the subpower Higson corona of proper metric spaces and show that the subpower Higson corona of the half open interval with the usual metric is an indecomposable continuum. Some surjective maps from the Higson type coronas onto the Higson type compactifications of the half open interval are also constructed., 13 pages

In this paper, we consider spaces whose Higson coronae are indecomposable continua. We show that for a non-compact proper metric space $X$ which is coarsely geodesic and has coarse bounded geometry, the Higson corona of $X$ is an indecomposable continuum if and only if $X$ is coarsely equivalent to the space of natural numbers. Then we give characterizations of finitely generated groups that have one or two ends by decomposability/indecomposability of the components of their Higson coronae. we characterize it as a group whose Higson corona is a topological sum of two indecomposable continua.

We designed specific primers for Coniothyrium minitans, a sclerotia-parasitizing biocontrol agent (BCA), and quantified its biomass in the field by quantitative polymerase chain reaction. Because chemical properties of the soil can decrease the DNA extraction efficiency and DNA polymerase activity, standard curves were calibrated by adding known concentrations of BCA to sterilized field soil. The BCA biomass was monitored over time and after various treatments. Because the distribution of the BCA biomass was uneven in the field, a method to spread BCA uniformly in the field is needed.

The suppressive potentials of Bacillus and Paenibacillus strains isolated from the tomato phyllosphere were investigated to obtain new biocontrol candidates against Fusarium crown and root rot of tomato. The suppressive activities of 20 bacterial strains belonging to these genera were examined using seedlings and potted tomato plants, and two Paenibacillus strains (12HD2 and 42NP7) were selected as biocontrol candidates against the disease. These two strains suppressed the disease in the field experiment. Scanning electron microscopy revealed that the treated bacterial cells colonized the root surface, and when the roots of the seedlings were treated with strain 42NP7 cells, the cell population was maintained on the roots for at least for 4 weeks. Although the bacterial strains had no direct antifungal activity against the causal pathogen in vitro, an increase was observed in the antifungal activities of acetone extracts from tomato roots treated with the cells of both bacterial strains. Furthermore, RT-PCR analysis verified that the expression of defense-related genes was induced in both the roots and leaves of seedlings treated with the bacterial cells. Thus, the root-colonized cells of the two Paenibacillus strains were considered to induce resistance in tomato plants, which resulted in the suppression of the disease.

We studied the relationship between the removal/recovery behavior and the chemical and physical properties of perfluoropolyether lubricants with different functional groups in metal-particulate flexible disk systems. The rotational speed dependence of the coefficient of sliding friction between disks and a spherical glass slider were measured. The dependence was found to be described by a simple equation in consideration of the removal/recovery behavior of the lubricant. The time constants in the equation were found to be almost proportional to the inverses of the extraction lifetimes estimated from the solvent-extraction profiles of lubricants on the disk surface. This result indicates that the affinity of the lubricant to the disk surface dominates the rate of recovery.

Eighty-five Pyricularia isolates were collected from 29 host species of Gramineae, Bambusideae and Zingiberaceae plants sampled in Brazil, Uganda, Ivory Coast, India, Nepal, China, Indonesia and Japan. These isolates were compared on the basis of pathogenicity, mating ability and restriction fragment length polymorphisms with single-copy DNA probes. Based on the pathogenicity to eight differential gramineous plants, these isolates were classified into seven pathotypes: finger millet type, foxtail millet type, common millet type, rice type, crabgrass type, Italian ryegrass/ weeping lovegrass type, and non-cereal/grass type. Genetic variation among these isolates was assessed by RFLP analysis with two restriction enzymes and nine single-copy DNA probes isolated from a finger millet strain. An UPGMA dendrogram based on the RFLPs revealed that the 85 isolates could be classified into seven major groups. Isolates from cereal crops (finger millet, foxtail millet, common millet, wheat and rice) and a grass, Brachiaria plantaginea, were clustered into a single group. They were further divided into six subgroups corresponding to the pathotypes. Among cereal crop isolates only an isolate from pearl millet was located into a different group. The remaining isolates were clustered into five groups designated as the crabgrass group, the buffelgrass and jungle rice group, the rice cutgrass, knotroot bristlegrass and Setaria tomentosa group, the bamboo and bamboo grass group and the Zingiber mioga group. The isolates from cereal crops were generally capable of mating with finger millet strains and constituted a closed mating compatibility group. These results suggested that the isolates from cereal crops form a single group with a common ancestor although they are pathogenic to taxonomically diverse plants. A combined analysis of the pathogenicity and genetic similarity suggested that the transmission of M. grisea isolates occurs in natural agroecosystems between finger millet and Eleusine africana, goosegrass or Bambusa arundinacea, between foxtail millet and green bristlegrass, and between rice and tall fescue, Italian ryegrass, sweet vernalgrass, reed canarygrass or Oryza longistaminata.

Polyion complexed mixed Langmuir–Blodgett (LB) films of amphiphiles with long fluorocarbon chains (PFECA [CF3(CF2)8(CH2)2O(CH2)2COOH] or perfluorodecanoic acid (PFDA) [CF3(CF2)8COOH]) and those with long hydrocarbon chains (stearic acid (STA) or doxylstearic acids (5-, 10- or 16-doxyslstearic acid) deposited on Si, glass substrates or polyethylene terephthalate (PETP) sheets were characterized by atomic force microscopy/friction force microscopy (AFM/FFM) and electron spin resonance (ESR) spectroscopy. AFM/FFM images of 1:1 mixed LB films of PFECA (or PFDA) and 16-DXSTA showed clear phase-separated structure, while those of PFECA (or PFDA) and 5-DXSTA did not. All the values of the frictional force for the LB films, which did not show clear phase-separated structure, were intermediate between those for PFECA and STA. ESR spectra of mixed LB films of PFECA and 16-DXSTA were almost the same as that of a polyion complexed LB film of pure 16-DXSTA. On the contrary, the ESR spectra of mixed LB films of PFECA, STA and 5-DXSTA were very different from those of mixed LB films of 5-DXSTA and STA. From these results it was concluded that in the polyion complexed 1:1 mixed LB films of 5-DXSTA and PFECA, 5-DXSTA and PFDA, and 10-DXSTA and PFDA, the amphiphilic molecules with fluorocarbon chains and those with hydrocarbon chains are mixed with each other on the molecular level. This finding shows that phase separation of mixed LB films containing amphiphiles with fluorocarbon chains and those with hydrocarbon chains can be controlled by the selection of the structure of amphiphiles.

Electron spin resonance (ESR) spectra for cast films and spin-coated films of stearic acid (STA), dioctadecyldimethylammonium chloride (DODAC) or didodecyldimethylammonium bromide (DDAB) mixed with spin probes, 5-doxylstearic acid (5-DXSTA) or 16-doxylstearic acid (16-DXSTA), were measured. The anisotropy of the ESR spectra was determined by varying the angle Θ, between the direction of the applied magnetic field and the direction normal to the sheet. The temperature dependence of the ESR spectra was measured to examine the effect of molecular motion on the ESR spectra. For the cast and spin-coated DODAC and DDAB films, a clear Θ dependence of the ESR spectra was observed, especially at higher temperature when 5-DXSTA was used as a spin probe, while the ESR spectra for these films were almost isotropic at higher temperature when 16-DXSTA was used as a spin probe. From this result, it was confirmed that the methylene chains close to the head groups in cast and spin-coated films of DODAC and DDAB were carrying out anisotropic rotational Brownian motion around the axis perpendicular to the film plane, while the tail parts of the methylene chains were doing almost isotropic rotational motion at higher temperature. The temperature dependence of the ESR spectra for cast and spin-coated films of DODAC and DDAB showed that the flexibility of methylene chains in DDAB films was larger than that in DODAC films, and this difference was ascribed to the difference in the gel-to-liquid crystal transition temperatures of DODAC and DDAB films. On the other hand, the ESR spectra for cast and spin-coated films of STA mixed with 5-DXSTA or 16-DXSTA did not show clear anisotropy anywhere in the temperature range used in this study. From this result, it was shown that amphiphiles in these films had a less ordered structure compared with those in DODAC and DDAB films.

Electron spin resonance spectra of the Langmuir-Blodgett films of 5-, 10-, and 16-doxylstearic acids (DXSTAs) and their mixtures with stearic acid complexed with polyallylamine, polyvinylmethylpyridinium iodide, and polyvinylbenzyltrimethylammonium chloride are measured at various angles between the magnetic field and the film normal. From the difference in the strength of Heisenberg spin exchange interaction among these three kinds of DXSTA films, it was indicated that the mobility of the methylene chain in these films increased with the distance from the head group. From the anisotropic properties of these spectra, it was also shown that the DXSTA molecules were well oriented with their methylene chain almost perpendicular to the film surface and were well arranged two dimensionally in the film plane.

Langmuir-Blodgett (LB) films of Cu2+ arachidate were prepared with two types of LB trough, i.e. a conventional ordinary trough and a moving-wall type trough. Electron spin resonance spectra and scanning probe microscope images of these LB films showed that the transfer of these monolayers onto a solid substrate was successfully attained with a moving-wall type trough, while it was difficult with a conventional trough.

A continuously tunable, phase-locked, THz synthesizer has been demonstrated. This THz synthesizer is based on photomixing of two optical frequency synthesizers composed of CW laser and optical comb, and its output frequency has the same uncertainty as that of a microwave frequency standard used.

We present arbitrary single-frequency continuous-wave (CW) terahertz (THz) generator based on photomixing of a scanned CW laser and a fixed CW laser, which are locked to two independent optical combs, respectively. Behavior of tight locking and continuous tuning of its output frequency is monitored at real time by a THz-comb-referenced spectrum analyzer.

In thispaper, we study Higson compactificationsof the half-openintervalobtained by expanding and contractingthe base space. We show that the Higson coronas of the half-openinterval obtained by these operationsare indecomposable continua. Moreover,we show that the Stone-Cech compactificationcan be approximated by such Higson compactifications. All spaces considered in this paper are assumed to be locally compact and Hausdorff. By C*(X), we denote the Banach algebra of all bounded real-valued continuous functions on X with the sup-norm. It is well-known that there is a one-to-one correspondence between the compactiflcations of a space X and the closed subrings of C*(X) containing the constants and generating the topology of X. Let / : X ―>■Y be a continuous function between metric spaces (X, d) and (Y,p). We say that the function / satisfiesthe (*)d-condition provided that (*)d lim diam.n/(i^(x, r)) = 0 for each r > 0, X―+CC that is, for each r > 0 and each e > 0, there is a compact set K = Kf)Ein X such that diamp f(Bd{x,r))

We constructed a widely and continuously tunable terahertz frequency synthesizer traceable to a hydrogen maser linked to coordinated universal time. Photomixing of two optical frequency synthesizers, linked to the hydrogen maser via dual optical frequency combs, gave this THz synthesizer frequency uncertainty of 10⁻¹². To demonstrate the potential of wide and continuous tunability in the THz synthesizer, we tuned its output frequency up to 50 GHz discretely and 1.26 GHz continuously in the F-band while maintaining the unprecedented frequency uncertainty by using a uni-traveling-carrier photodiode as a photomixer. This THz synthesizer will be a powerful tool for broadband, high-precision THz spectroscopy and THz frequency metrology.

A continuously tunable, phase-locked, single-frequency, continuous-wave (cw) terahertz generator has been demonstrated around 120 GHz, corresponding to the spectral bandwidth of the F-band unitraveling-carrier photodiode (UTC-PD) used as a photomixer in this study. This cw-terahertz generator is based on photomixing of an accurately tunable cw laser and a tightly fixed cw laser in the optical frequency region, phase locked to two independent optical combs. The continuous tuning range of the presented method was three orders of magnitude around 0.1 THz and two orders around 1 THz broader than that of a previous photomixing method in which two cw lasers are phase locked to a single optical comb, and fully covered the available spectral bandwidth of the F-band UTC-PD. The spectral behavior of the tight locking and continuous tuning of 120 GHz cw-terahertz radiation was confirmed in real time by use of a terahertz-comb-referenced spectrum analyzer. This cw-terahertz generator shows promise as a terahertz clock and synthesizer for terahertz frequency metrology.

Let G be a compact separable zero-dimensional group with the unit element e. We construct semifree G-actions on Menger manifolds with G-invariant pseudo-interiors and pseudo-boundaries. The main purpose of this paper is to prove the following: For each closed subset X of a Menger manifold M, there exists a semifree G-action on M such that X is the fixed point set of any g ϵ G ⧹ {e}. This gives the affirmative answers to the questions in K. Sakai, Preprint and in A. Chigogidze, K. Kawamura and E.D. Tymchatyn, Problems 6.4.3, 6.4.4 in full generality. The pseudo-interiors and the pseudo-boundaries versions of the theorem above are also given. Moreover, free G-actions on pseudo-interiors and pseudo-boundaries of Menger manifolds are constructed.

Let µ n+1 be the (n + 1)-dimensional universal Menger compactum. It is known that the nshape category of Z-sets in µ n+1 is isomorphic to the weak proper n-homotopy category of their complements. In this paper, we introduce the (n + 1)-skeletal conic telescope to define the strong n-shape category of compacta, and show that the strong n-shape category of Z-sets in µ n+1 is isomorphic to the proper n-homotopy category of their complements.  2002 Elsevier Science B.V. All rights reserved. AMS classification:54C56; 57N25

Arbitrary single-frequency CW-THz-wave generator based on two-independent femtosecond fiber-combs is presented. Continuous tuning of a 120-GHz CW wave was demonstrated across several MHz, which is limited by electric bandwidth of THz-spectrum analyzer for evaluation.