4,301 research outputs found

    Collaboration for diagnosis of Xanthomonas citri pv. mangiferaeindicae causing mango bacterial canker on Mangifera indica in Myanmar : [P2-10]

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    During 2006-2008, mango disease survey training for pest Iist development was supported under the ASEAN Australia Development Co-operation Program (AADCP) Program Stream: Strengthening ASEAN Plant Health Capacity Project (1). The project involved regional training workshops and practical experience in surveying and disease diagnostics in selected ASEAN countries, in partnership with Australian mango pest and disease specialists. The surveying also provided an opportunity for extending collaboration with CIRAD and for strengthening CIRAD-ASEAN links, when specialist expertise in bacterial disease diagnostics was required. Bacterial canker of mango (or bacterial black spot) caused by #Xanthomonas citri pv. Mangiferaeindicae# (2) is a disease of economic importance in tropical and subtropical producing areas. #X. citri pv. Mangiferaeindicae# can cause severe infection in a wide range of mango cultivars and induces raised, angular, black leaf lesions, sometimes with a chlorotic halo. Suspected leaf lesions of bacterial canker were collected from mango nursery stock cv. Yin Kwe at a nursery in Yangon, Myanmar during March 2007. Sub-samples of representative accessions were dispatched by air-courier to 2CIRAD UMR PVBMT, La Réunion, with additional reference material retained in the plant disease herbarium of'PPD. In tests at CIRAD UMR PVBMT2, nonpigmented Xanthomonas-like bacterial colonies were isolated on KC and NCTM3 semiselective agar media (4,7). Amplified fragment length polymorphism analysis was performed on three isolates from Myanmar and additional reference isolates of xanthomonads originating from Anacardiaceae (#X. citri pv. Anacardii#, #X. citri pv. Mangiferaeindicae#, #X. axonopodis pv. Spondiae#, and #X. translucens# strains from pistachio) (2, 4). On the basis of multidimensional scaling (2), the Myanmar isolates were identified as #X. citri pv. Mangiferaeindicae# and were most closely related to group B strains that were isolated from mango in India and Eastern Asia (5). Mango cv. Maison Rouge leaves, inoculated as previously reported (3) with the Myanmar isolates, showed typical symptoms of bacterial canker 1 week after inoculation. One month after inoculation, mean #X. citri pv. Mangiferaeindicae# population sizes ranging from 5 x 106 to 8 x 106 CFU per lesion were recovered from leaf lesions, typical of a compatible interaction (3). #Mangifera indica# L. probably evolved in the area that includes northwestern Myanmar (6) and to our knowledge, this is the first confirmed detection of #X. citri pv. Mangiferaeindicae# from Myanmar. Further surveys and strain collection will be necessary to evaluate its geographic distribution and prevalence in the country (4). The diagnosis and confirmation of bacterial spot on mango from Myanmar (4) has assisted in the development of Myanmar's mango pest list, and enabled Myanmar partners to gain experience in international collaboration in plant disease specimen dispatch and diagnostics. (Résumé d'auteur

    Do Employees From Less-Healthy Communities Use More Care and Cost More? Seeking to Establish a Business Case for Investment in Community Health.

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    INTRODUCTION: Few studies have examined the impact of community health on employers. We explored whether employed adults and their adult dependents living in less-healthy communities in the greater Philadelphia region used more care and incurred higher costs to employers than employees from healthier communities. METHODS: We used a multi-employer database to identify adult employees and dependents with continuous employment and mapped them to 31 zip code regions. We calculated community health scores at the regional level, by using metrics similar to the Robert Wood Johnson Foundation (RWJF) County Health Rankings but with local data. We used descriptive analyses and multilevel linear modeling to explore relationships between community health and 3 outcome variables: emergency department (ED) use, hospital use, and paid claims. Business leaders reviewed findings and offered insights on preparedness to invest in community health improvement. RESULTS: Poorer community health was associated with high use of ED services, after controlling for age and sex. After including a summary measure of racial composition at the zip code region level, the relationship between community health and ED use became nonsignificant. No significant relationships between community health and hospitalizations or paid claims were identified. Business leaders expressed interest in further understanding health needs of communities where their employees live. CONCLUSION: The health of communities in which adult employees and dependents live was associated with ED use, but similar relationships were not seen for hospitalizations or paid claims. This finding suggests a need for more primary care access. Despite limited quantitative evidence, business leaders expressed interest in guidance on investing in community health improvement

    Genetic Structure of the Rice Blast Pathogen (Magnaporthe oryzae) over a Decade in North Central California Rice Fields.

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    Rice blast, caused by the ascomycete Magnaporthe oryzae, is one of the most destructive rice diseases worldwide. Even though the disease has been present in California since 1996, there is no data for the pathogen population biology in the state. Using amplified fragment length polymorphisms and mating-type markers, the M. oryzae population diversity was investigated using isolates collected when the disease was first established in California and isolates collected a decade later. While in the 1990 samples, a single multilocus genotype (MLG) was identified (MLG1), over a decade later, we found 14 additional MLGs in the 2000 isolates. Some of these MLGs were found to infect the only rice blast-resistant cultivar (M-208) available for commercial production in California. The same samples also had a significant decrease of MLG1. MLG1 was found infecting the resistant rice cultivar M-208 on one occasion whereas MLG7 was the most common genotype infecting the M-208. MLG7 was identified in the 2000 samples, and it was not present in the M. oryzae population a decade earlier. Our results demonstrate a significant increase in genotypic diversity over time with no evidence of sexual reproduction and suggest a recent introduction of new virulent race(s) of the pathogen. In addition, our data could provide information regarding the durability of the Pi-z resistance gene of the M-208. This information will be critical to plant breeders in developing strategies for deployment of other rice blast resistance genes/cultivars in the future

    Immigration, trade and productivity in services:evidence from UK firms

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    This paper explores the impact of immigrants on the imports, exports and productivity of serviceproducing firms in the U.K. Immigrants may substitute for imported intermediate inputs (offshore production) and they may impact the productivity of the firm as well as its export behavior. The first effect can be understood as the re-assignment of offshore productive tasks to immigrant workers. The second can be seen as a productivity or cost cutting effect due to immigration, and the third as the effect of immigrants on specific bilateral trade costs. We test the predictions of our model using differences in immigrant inflows across U.K. labor markets, instrumented with an enclave-based instrument that distinguishes between aggregate and bilateral immigration, as well as immigrant diversity. We find that immigrants increase overall productivity in service-producing firms, revealing a cost cutting impact on these firms. Immigrants also reduce the extent of country-specific offshoring, consistent with a reallocation of tasks and, finally, they increase country-specific exports, implying an important role in reducing communication and trade costs for services

    Black Holes at the LHC

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    If the scale of quantum gravity is near a TeV, the LHC will be producing one black hole (BH) about every second. The BH decays into prompt, hard photons and charged leptons is a clean signature with low background. The absence of significant missing energy allows the reconstruction of the mass of the decaying BH. The correlation between the BH mass and its temperature, deduced from the energy spectrum of the decay products, can test experimentally the higher dimensional Hawking evaporation law. It can also determine the number of large new dimensions and the scale of quantum gravity.Comment: 5 pages, 3 figures, submitted to PRL. Results presented at the Les Houches Workshop "Physics at the TeV Colliders" (May 30, 2001) and the "Avatars of M-Theory" conference, ITP at Santa Barbara (June 7, 2001), http://online.itp.ucsb.edu/online/mtheory_c01/dimopoulo

    Failure of Intravenous Morphine to Serve as an Effective Instrumental Reinforcer in Dopamine D2 Receptor Knock-Out Mice

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    The rewarding effects of opiates are thought to be mediated through dopaminergic mechanisms in the ventral tegmental area, dopamine-independent mechanisms in the nucleus accumbens, or both. The purpose of the present study was to explore the contribution of dopamine to opiate-reinforced behavior using D2 receptor knock-out mice. Wild-type, heterozygous, and D2 knock-out mice were first trained to lever press for water reinforcement and then implanted with intravenous catheters. The ability of intravenously delivered morphine to maintain lever pressing in these mice was studied under two schedules of reinforcement: a fixed ratio 4 (FR4) schedule (saline, 0.1, 0.3, or 1.0 mg/kg, per injection) and a progressive ratio (PR) schedule (1.0 mg/kg, per injection). In the wild-type and heterozygous mice, FR4 behavior maintained by morphine injections was significantly greater than behavior maintained by vehicle injections. Response rate was inversely related to injection dose and increased significantly in the wild-type and heterozygous mice when the animals were placed on the PR schedule. In contrast, the knock-out mice did not respond more for morphine than for saline and did not respond more when increased ratios were required by the PR schedule. Thus, morphine served as a positive reinforcer in the wild-type and heterozygous mice but failed to do so in the knock-out mice. Under this range of doses and response requirements, the rewarding effects of morphine appear to depend critically on an intact D2 receptor systemFil: Elmer, Greg I.. University of Maryland; Estados UnidosFil: Pieper, Jeanne O.. National Institutes of Health; Estados UnidosFil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Low, Malcolm J.. Oregon Health and Sciences University; Estados UnidosFil: Grandy, David K.. Oregon Health and Sciences University; Estados UnidosFil: Wise, Roy A.. National Institutes of Health; Estados Unido

    Direct-write, focused ion beam-deposited,7 K superconducting C-Ga-O nanowire

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    We have fabricated C-Ga-O nanowires by gallium focused ion beam-induced deposition from the carbon-based precursor phenanthrene. The electrical conductivity of the nanowires is weakly temperature dependent below 300 K, and indicates a transition to a superconducting state below Tc = 7 K. We have measured the temperature dependence of the upper critical field Hc2(T), and estimate a zero temperature critical field of 8.8 T. The Tc of this material is approximately 40% higher than that of any other direct write nanowire, such as those based on C-W-Ga, expanding the possibility of fabricating direct-write nanostructures that superconduct above liquid helium temperaturesComment: Accepted for AP

    Phosphoproteomics identifies a bimodal EPHA2 receptor switch that promotes embryonic stem cell differentiation

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    Embryonic Stem Cell (ESC) differentiation requires complex cell signalling network dynamics, although the key molecular events remain poorly understood. Here, we use phosphoproteomics to identify an FGF4-mediated phosphorylation switch centred upon the key Ephrin receptor EPHA2 in differentiating ESCs. We show that EPHA2 maintains pluripotency and restrains commitment by antagonising ERK1/2 signalling. Upon ESC differentiation, FGF4 utilises a bimodal strategy to disable EPHA2, which is accompanied by transcriptional induction of EFN ligands. Mechanistically, FGF4-ERK1/2-RSK signalling inhibits EPHA2 via Ser/Thr phosphorylation, whilst FGF4-ERK1/2 disrupts a core pluripotency transcriptional circuit required for Epha2 gene expression. This system also operates in mouse and human embryos, where EPHA receptors are enriched in pluripotent cells whilst surrounding lineage-specified trophectoderm expresses EFNA ligands. Our data provide insight into function and regulation of EPH-EFN signalling in ESCs, and suggest that segregated EPH-EFN expression coordinates cell fate with compartmentalisation during early embryonic development

    Performance Analysis of Apollo Navigational Starter Routine

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    The focus of this project is to recreate and analyze the effectiveness of the original Apollo Starter Routine (ASR) which was used to generate the state vector of the Apollo spacecraft based on a series of radiometric observations. The original Apollo navigation software is unavailable in a modern programming language and the original coding has not been preserved. This necessitates its recreation using the original software documentation. Space Shuttle navigation software does not typically use the ASR or an algorithm like it since the Shuttle s state vector is easily deduced from GPS information or other sources. However, this tactic will be ineffective when trying to determine the state vector of a craft approaching, departing or in orbit around the Moon since the GPS network faces the surface of the Earth, not outer space. The recreation of the ASR from the original documentation is therefore vital as a simulation baseline for the navigation software under development for the Constellation program. The algorithms that make up the ASR will be extracted from the original documentation and adapted for and then implemented in a modern programming language; the majority of it will be coded in Matlab. The ASR s effectiveness will then be tested using simulated tracking data. The ability of the ASR to handle realistically noisy data and the accuracy with which it generates state vectors were analyzed. The ASR proved to be robust enough to process data with range and angle noise as large as 10,000 meters and 10(exp -6) radians together and 300,000 meters and 5x10(exp -4) radians separately at Lunar distances. The ASR was able to handle marginally more noise at distances closer to the Earth where the angle noise was less significant. The ASR is capable of effectively processing 40-80 data points gathered at a rate of one per 20 seconds at close Earth orbit and up to 28-40 data points gathered at a rate of one per minute at distant Earth orbit and Lunar orbit
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