767 research outputs found

    Effect of fungal interactions on the numbers of the pinewood nematode, Bursaphelenchus xylophilus (Nematoda : Aphelenchoididae), carried by the japanese pine sawyer, Monochamus alternatus (Coleoptera : Cerambycidae)

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    #Monochamus alternatus sortant de blocs de bois préalablement inoculés avec #Ophiostoma minus et ensuite avec #Trichoderma sp. (O + T) transporte un plus grand nombre de #Bursaphelenchus xylophilus (PWN) que ceux sortant de blocs inoculés simultanément avec ces deux champignons (O, T) ou inoculés avec #Trichoderma sp. puis avec #O. minus (T + O). La raison est que : les populations de PWN sont plus élevées dans les blocs O + T que dans ceux des autres traitements, et que le pourcentage de juvéniles de dispersion de 3Úme stade, les "dauer" juvéniles et les PWN qui passent réellement dans l'insecte sont plus nombreux dans les blocs O + T. En contraste, le nombre de PWN transportés par l'insecte sortant de blocs inoculés avec #O. minus et #Verticillium sp. est beaucoup moins élevé quelle que soit la séquence d'innoculum parce que les populations de PWN ne s'établissent pas. Il est conclu que les espÚces de champignon les plus abondantes dans les pins tués par le dessÚchement concourent à déterminer le nombre de PWN transportés par l'insecte sortant du bois. (Résumé d'auteur

    A heavy Higgs boson from flavor and electroweak symmetry breaking unification

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    We present a unified picture of flavor and electroweak symmetry breaking based on a nonlinear sigma model spontaneously broken at the TeV scale. Flavor and Higgs bosons arise as pseudo-Goldstone modes. Explicit collective symmetry breaking yields stable vacuum expectation values and masses protected at one loop by the little-Higgs mechanism. The coupling to the fermions generates well-definite mass textures--according to a U(1) global flavor symmetry--that correctly reproduce the mass hierarchies and mixings of quarks and leptons. The model is more constrained than usual little-Higgs models because of bounds on weak and flavor physics. The main experimental signatures testable at the LHC are a rather large mass m_{h^0} = 317\pm 80 GeV for the (lightest) Higgs boson and a characteristic spectrum of new bosons and fermions at the TeV scale.Comment: 5 page

    KIC 4150611: a rare multi-eclipsing quintuple with a hybrid pulsator

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    We present the results of our analysis of KIC 4150611 (HD 181469) - an interesting, bright quintuple system that includes a hybrid ÎŽ\delta Sct/Îł\gamma Dor pulsator. Four periods of eclipses - 94.2, 8.65, 1.52 and 1.43 d - have been observed by the Kepler satellite, and three point sources (A, B, and C) are seen in high angular resolution images. From spectroscopic observations made with the HIDES spectrograph attached to the 1.88-m telescope of the Okayama Astrophysical Observatory (OAO), for the first time we calculated radial velocities (RVs) of the component B - a pair of G-type stars - and combined them with Kepler photometry in order to obtain absolute physical parameters of this pair. We also managed to directly measure RVs of the pulsator, also for the first time. Additionally, we modelled the light curves of the 1.52 and 1.43-day pairs, and measured their eclipse timing variations (ETVs). We also performed relative astrometry and photometry of three sources seen on the images taken with the NIRC2 camera of the Keck II telescope. Finally, we compared our results with theoretical isochrones. The brightest component Aa is the hybrid pulsator, transited every 94.2 days by a pair of K/M-type stars (Ab1+Ab2), which themselves form a 1.52-day eclipsing binary. The components Ba and Bb are late G-type stars, forming another eclipsing pair with a 8.65 day period. Their masses and radii are MBa=0.894±0.010M_{Ba}=0.894\pm0.010 M⊙_\odot, RBa=0.802±0.044R_{Ba}=0.802\pm0.044 R⊙_\odot for the primary, and MBb=0.888±0.010M_{Bb}=0.888\pm0.010 M⊙_\odot, RBb=0.856±0.038R_{Bb}=0.856\pm0.038 R⊙_\odot for the secondary. The remaining period of 1.43 days is possibly related to a faint third star C, which itself is most likely a background object. The system's properties are well-represented by a 35 Myr isochrone. There are also hints of additional bodies in the system.Comment: 14 pages, 15 figures, 7 tables, to appear in A&A, abstract modified in order to fit the arXiv limi

    Photometric Properties of Kiso Ultraviolet-Excess Galaxies in the Lynx-Ursa Major Region

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    We have performed a systematic study of several regions in the sky where the number of galaxies exhibiting star formation (SF) activity is greater than average. We used Kiso ultraviolet-excess galaxies (KUGs) as our SF-enhanced sample. By statistically comparing the KUG and non-KUG distributions, we discovered four KUG-rich regions with a size of ∌10∘×10∘\sim 10^\circ \times 10^\circ. One of these regions corresponds spatially to a filament of length ∌60h−1\sim 60 h^{-1} Mpc in the Lynx-Ursa Major region (α∌9h−10h,Ύ∌42∘−48∘\alpha \sim 9^{\rm h} - 10^{\rm h}, \delta \sim 42^\circ - 48^\circ). We call this ``the Lynx-Ursa Major (LUM) filament''. We obtained V(RI)CV(RI)_{\rm C} surface photometry of 11 of the KUGs in the LUM filament and used these to investigate the integrated colors, distribution of SF regions, morphologies, and local environments. We found that these KUGs consist of distorted spiral galaxies and compact galaxies with blue colors. Their star formation occurs in the entire disk, and is not confined to just the central regions. The colors of the SF regions imply that active star formation in the spiral galaxies occurred 107−810^{7 - 8} yr ago, while that of the compact objects occurred 106−710^{6-7} yr ago. Though the photometric characteristics of these KUGs are similar to those of interacting galaxies or mergers, most of these KUGs do not show direct evidence of merger processes.Comment: 39 pages LaTeX, using aasms4.sty, 20 figures, ApJS accepted. The Title of the previous one was truncated by the author's mistake, and is corrected. Main body of the paper is unchange

    Pemphigus foliaceus

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    Pemphigus foliaceus (PF) is a group of autoimmune skin blistering disease comprising four subtypes: Cazenave, endemic, erythematosus and herpetiformis. The common characteristic is the frequent presence of pathogenic anti-desmoglein 1 antibodies leading to bullae in the skin. Other characteristics-clinical, histological, pathogenesis and therapy-vary and are specified in this chapter. Pemphigus foliaceus first described by Cazenave is the classical form of PF. The elemental dermatological lesions are erythematous plaques with pastry puff squames predominantly affecting seborrhoeic areas. The histopathological hallmark is acantholysis in the upper part of the epidermis (subcorneal or intraspinous). The disease is caused by autoantibodies to desmoglein 1 on the epithelial cell surface. Therapy is based on systemic corticosteroids, rituximab and immunosuppressive adjuvants. Rituximab an anti-CD20 biologics targeting B-lymphocytes have changed the prognosis of the disease from chronic relapsing to long-term remissions. Endemic pemphigus is a variant of PF. The disease is endemic in South-American countries especially in rural regions of Brazil, but also in Colombia, Paraguay, Peru, Venezuela and also in Africa in Tunisia. The histopathology, immunology and therapy are similar to classical form of PF.</p

    Study on Control Performance of HVAC System or Interior Zone and Perimeter Zone in Office Building; Estimation of Optimal PI Tuning in Cooling Operation

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    In office buildings there are generally two HVAC systems installed, one in the perimeter zone (PZ) and one in the interior zone (IZ), and the temperatures of each zone are independently controlled. In the present paper, in order to the solve problem of not being able to satisfy the requirements of room temperature control during the cooling period in summer, an optimal PID parameter (O-PI) is selected through simulation of its two feedback control systems with mutual influence using the models identified with the experimental data. The step response characteristics of the system with optimal parameters compared to those with the parameters selected by the Ziegler-Nichols Method (ZNM-PI) that are generally used for PID parameter tuning on site. The result shows O-PI improved control performance, and the difference between O-PI and ZNM-PI can be used to readjust ZNM-PI selected on site

    NK4, a four-kringle antagonist of HGF, inhibits spreading and invasion of human pancreatic cancer cells

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    Because of the highly aggressive behaviour, i.e. invasive, disseminative and metastatic properties, the outcome for patients with pancreatic cancer is morbid. A better understanding and interference with the malignant behaviour of pancreatic cancer may provide new directions for treatment. We report here the induction of highly motile and invasive properties in human pancreatic cancer cells by hepatocyte growth factor (HGF) and blockage of these properties by NK4, a newly identified antagonist for HGF. In all of eight human pancreatic cancer cell lines we used (AsPC-1, BxPC-3, H-48N, KP-1N, KP-2, KP-3, MIA PaCa-2 and SUIT-2 cells), the c-Met/HGF receptor was expressed at varying levels. Although weak mitogenic activity of HGF was seen only in SUIT-2 and KP-3 cells, HGF strongly stimulated migration and invasion of these pancreatic cancer cells, except for BxPC-3 and MIA PaCa-2 cells. In contrast, migration and invasion potently induced by HGF in KP-1N, KP-3 and SUIT-2 cells were inhibited by NK4. The invasion of SUIT-2 cells was also potently stimulated with the influence of cocultured pancreatic fibroblasts and by ascitic fluid obtained after pancreatic cancer resection, however, invasiveness of the cancer cells in such conditions was practically abolished by NK4. Consistently, the ascitic fluid in patients who had undergone pancreatic cancer surgery contained high levels of HGF. These findings mean that HGF is probably involved in invasion, dissemination, and metastasis of pancreatic cancer, particularly through tumour-stromal interaction and after resection of the pancreatic cancer. NK4, an effective antagonist of HGF, may prove to have the potential for anti-invasion/metastasis. © 2001 Cancer Research Campaign http://www.bjcancer.co
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