928 research outputs found

    Clay mineralogy of tephras and associated paleosols and soils, and hydrothermal deposits, North Island [New Zealand]

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    Tour themes and itinerary The tour centres on the occurrence and genesis of clay minerals, especially allophane, halloysite, and ferrihydrite, associated with both Quaternary rhyolitic airfall tephra (volcanic ash) deposits and volcanogenic alluvium, and on mineralisation and thermal activity in hydrothermal fields. After a brief overview of the basaltic volcanoes of Auckland City, our route essentially traverses the Central Volcanic Region by way of a large loop with overnight stops at Rotorua (2 nights), Tokaanu, and Auckland (Fig. 0.1). We have around five stops planned for each day (including lunch), three of these being scientific stops except on Day 4 when we have only one scientific stop because of the need to travel greater distances. Our route takes us progressively towards the locus of the most recently active volcanic centres of the Central Volcanic Region, and so the surficial tephra deposits and buried paleosols become successively younger and generally less weathered: tephras at the Mangawara section (Day 1) span c. 1 Ma; at Tapapa (Day 2), c. 140 ka; at Te Ngae (Day 2), c. 20 ka; and at De Bretts, c. 10 ka, and Wairakei, c. 2 ka (Day 3). Interspersed with these tephra-paleosol sections are stops to examine an allophane-halloysite soil drainage (leaching) sequence on volcanogenic alluvium (Day 1), hydrothermal activity and mineral deposits at Whakarewarewa (Day 2) and Waiotapu (Day 3), and pure ferrihydrite seepage deposits in Hamilton (Day 4). Following introductory and detailed background review material, the tour guide has been arranged on a day-by-day basis and includes an outline of the route and stops, and several pages describing the stratigraphy, mineralogy, chemistry, and pedology of the deposits or features at each of the main stops. We will attempt to point out and describe geological and other features as appropriate during travel periods. Other activities Examples of New Zealand's distinctive fauna and flora, including kiwis and tuataras, will be seen at close quarters at Rainbow Springs (Day 2), where we will also enjoy an agricultural farm show. In Rotorua we will partake in a Maori hangi (steam-cooked feast) and concert including traditional dance forms (hakas) and songs (Day 2). In Tokaanu, hot pools will be available to relax in near the slopes of Mt Tongariro (Day 3). At Waitomo, we will visit the Waitomo Cave and in Hamilton spend a short time at the Waikato Museum of Art and History (Day 4). Finally, the tour will conclude with a farewell dinner in Auckland

    A mapping approach to synchronization in the "Zajfman trap". II: the observed bunch

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    We extend a recently introduced mapping model, which explains the bunching phenomenon in an ion beam resonator for two ions [Geyer, Tannor, J. Phys. B 37 (2004) 73], to describe the dynamics of the whole ion bunch. We calculate the time delay of the ions from a model of the bunch geometry and find that the bunch takes on a spherical form at the turning points in the electrostatic mirrors. From this condition we derive how the observed bunch length depends on the experimental parameters. We give an interpretation of the criteria for the existence of the bunch, which were derived from the experimental observations by Pedersen et al [Pedersen etal, Phys. Rev. A 65 042704].Comment: 25 pages, 6 figures; added new section 5 and clarified text; submitted to J. Phys.

    Improved primordial non-gaussianity constraints from measurements of galaxy clustering and the integrated Sachs-Wolfe effect

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    We present the strongest robust constraints on primordial non-Gaussianity (PNG) from currently available galaxy surveys, combining large-scale clustering measurements and their cross-correlations with the cosmic microwave background. We update the data sets used by Giannantonio et al. (2012), and broaden that analysis to include the full set of two-point correlation functions between all surveys. In order to obtain the most reliable constraints on PNG, we advocate the use of the cross-correlations between the catalogs as a robust estimator and we perform an extended analysis of the possible systematics to reduce their impact on the results. To minimize the impact of stellar contamination in our luminous red galaxy (LRG) sample, we use the recent Baryon Oscillations Spectroscopic Survey catalog of Ross et al. (2011). We also find evidence for a new systematic in the NVSS radio galaxy survey similar to, but smaller than, the known declination-dependent issue; this is difficult to remove without affecting the inferred PNG signal, and thus we do not include the NVSS auto-correlation function in our analyses. We find no evidence of primordial non-Gaussianity; for the local-type configuration we obtain for the skewness parameter 36<fNL<45 -36 < f_{\mathrm{NL}} < 45 at 95 % c.l. (5±215 \pm 21 at 1σ1\sigma) when using the most conservative part of our data set, improving previous results; we also find no evidence for significant kurtosis, parameterized by gNLg_{\mathrm{NL}}. In addition to PNG, we simultaneously constrain dark energy and find that it is required with a form consistent with a cosmological constant.Comment: 24 pages, 16 figures. More conservative treatment of the NVSS data, version accepted by Phys. Rev.

    Elucidation of the molecular responses during the primary infection of wild blueberry phenotypes with Monilinia vaccinii-corymbosi under field conditions

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    Background - Monilinia blight caused by Monilinia vaccinii-corymbosi (Reade) Honey (M.vc) is a major disease of wild blueberry that can result in severe crop losses in the absence of an integrated disease management programme. The fungus causes blight in the emerging floral and vegetative buds, but the degree of susceptibility varies among the different wild blueberry phenotypes, ranging from the highly susceptible V. a. f. nigrum to the moderately susceptible V. angustifolium and the least susceptible V. myrtilloides. Results - The present study evaluated the defense responses of these major phenotypes during their primary infection (floral buds) with M.vc. The temporal expression profiles of PR genes (PR3 and PR4) and the flavonoid pathway structural genes (CHS, ANS, ANR, DFR and FLS) were analysed. The PR3 and PR4 gene expression profiles revealed that V. myrtilloides responded to M.vc infection by activating the expression of both PR genes. V. a. f. nigrum, on the other hand, failed to activate these genes, while V. angustifolium, exhibited an intermediate response. Our study with the flavonoid pathway genes indicated variability in activation of the genes during post-infection time points with ANS and ANR in V. myrtilloides, FLS in V. angustifolium and no response observed in V. a. f. nigrum. Conclusions - Altogether, this study highlights that the degree of phenotype susceptibility is associated with the timely activation of host defense responsive genes. Data obtained in this study provided a starting point for a better understanding of the wild blueberry- M. vaccinii-corymbosi pathosystem

    Susceptibility to Botrytis blight at different floral stages of wild blueberry phenotypes

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    Botrytis blossom blight is an important disease of wild blueberries with yield losses in excess of 20% frequently occurring. Two field experiments were conducted in 2016 and 2017 to determine the susceptibility of four phenotypes (Vaccinium angustifolium, V. angustifolium f. nigrum, V. myrtilloides and V. angustifolium var. Fundy] at different floral stages [(Bud break (F5); bud prebloom; (F6), corolla fully open (F7), and senescent corolla (F8)] to Botrytis infection. Specific flower clusters on tagged stems from different phenotypes were inoculated with Botrytis cinerea conidial suspension (106 conidia·ml-1). Disease development were assessed eight days after inoculation. Disease incidence and severity in phenotype ranged from 14.1 to 22.6% and 37.4 to 42.3% in 2016, respectively, and 39.8 to 44.1% and 9.70 to 19.1% in 2017, respectively. Results indicated that V. angustifolium was the most susceptible followed by V. angustifolium f. nigrum and V. angustifolium var. Fundy. Vaccinium myrtilloides was found to be least susceptible. Incidence and severity on floral stages ranged from 2.95 to 36.4% and 7.81 to 75.5% in 2016, respectively, and 7.28 to 66.9% and 11.1 to 27.1% in 2017, respectively. Floral stage F7 was the most susceptible with incidence up to 66.9% and severity up to 75.5% followed by F6, F5 and F8. Therefore, results from this study indicated that V. myrtilloides was less susceptible to B. cinerea than V. angustifolium phenotypes, and F6 and F7 stages were the most susceptible to Botrytis blight. These results will assist producers in making more informed decisions on Botrytis blight control and as its management practices shift from blanket to precise delivery of disease control products

    Nitric oxide regulates skeletal muscle fatigue, fiber type, microtubule organization, and mitochondrial ATP synthesis efficiency through cGMP-dependent mechanisms

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    Aim: Skeletal muscle nitric oxide–cyclic guanosine monophosphate (NO-cGMP) pathways are impaired in Duchenne and Becker muscular dystrophy partly because of reduced nNOSμ and soluble guanylate cyclase (GC) activity. However, GC function and the consequences of reduced GC activity in skeletal muscle are unknown. In this study, we explore the functions of GC and NO-cGMP signaling in skeletal muscle. Results: GC1, but not GC2, expression was higher in oxidative than glycolytic muscles. GC1 was found in a complex with nNOSμ and targeted to nNOS compartments at the Golgi complex and neuromuscular junction. Baseline GC activity and GC agonist responsiveness was reduced in the absence of nNOS. Structural analyses revealed aberrant microtubule directionality in GC1−/− muscle. Functional analyses of GC1−/− muscles revealed reduced fatigue resistance and postexercise force recovery that were not due to shifts in type IIA–IIX fiber balance. Force deficits in GC1−/− muscles were also not driven by defects in resting mitochondrial adenosine triphosphate (ATP) synthesis. However, increasing muscle cGMP with sildenafil decreased ATP synthesis efficiency and capacity, without impacting mitochondrial content or ultrastructure. Innovation: GC may represent a new target for alleviating muscle fatigue and that NO-cGMP signaling may play important roles in muscle structure, contractility, and bioenergetics. Conclusions: These findings suggest that GC activity is nNOS dependent and that muscle-specific control of GC expression and differential GC targeting may facilitate NO-cGMP signaling diversity. They suggest that nNOS regulates muscle fiber type, microtubule organization, fatigability, and postexercise force recovery partly through GC1 and suggest that NO-cGMP pathways may modulate mitochondrial ATP synthesis efficiency

    \u3cem\u3eMonilinia vaccinii-corymbosi\u3c/em\u3e sensitivity to demethylation inhibitor fungicides and its effect on Monilinia blight control in wild blueberry fields

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    Monilinia vaccinii-corymbosi (Reade) Honey (M.vc), the causal agent of Monilinia blight of wild blueberry, is controlled primarily by fungicide applications. Demethylation-inhibiting fungicides (DMIs) have been used for over 30 years for Monilinia blight control due to flexibility of use (i.e., ability to use after an infection period) and disease control effectiveness and consistency. In the present study, the sensitivity of ten M.vc isolates to three DMIs- propiconazole, difenoconazole and prothioconazole-desthio were evaluated in vitro by a mycelial growth inhibition assay. In addition, four field trials were conducted during two crop seasons: 2012 and 2013, to examine the efficacy of these DMIs to control Monilinia blight. All the tested DMIs were effective in inhibiting mycelial growth of M.vc isolates, although the mean EC50 values differed significantly. In field experiments, three of four trials had significant treatment effect on disease incidence and severity of vegetative buds. Prothioconazole-desthio and propiconazole provided consistent control against Monilinia blight. Conversely, difenoconazole was effective in in vitro analysis, but did not demonstrate satisfactory Monilinia blight control in all field trials. In the 2012 trials, both prothioconazole-desthio and propiconazole reduced disease incidence of vegetative buds by 100% compared to the untreated control. Prothioconazole- desthio reduced disease development in 2013 with 94 and 99.8% less incidence, and 75 and 99.5% less severity. Similarly, propiconazole also reduced incidence of vegetative buds by 88% and 99.8%, and severity by 54% and 99.7%. No phytotoxic symptoms were observed in any of the field trials. The results of the study serve as a benchmark to monitor shifts in M.vc sensitivity to these fungicides in the future

    The WiggleZ Dark Energy Survey: the selection function and z=0.6 galaxy power spectrum

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    We report one of the most accurate measurements of the three-dimensional large-scale galaxy power spectrum achieved to date, using 56,159 redshifts of bright emission-line galaxies at effective redshift z=0.6 from the WiggleZ Dark Energy Survey at the Anglo-Australian Telescope. We describe in detail how we construct the survey selection function allowing for the varying target completeness and redshift completeness. We measure the total power with an accuracy of approximately 5% in wavenumber bands of dk=0.01 h/Mpc. A model power spectrum including non-linear corrections, combined with a linear galaxy bias factor and a simple model for redshift-space distortions, provides a good fit to our data for scales k < 0.4 h/Mpc. The large-scale shape of the power spectrum is consistent with the best-fitting matter and baryon densities determined by observations of the Cosmic Microwave Background radiation. By splitting the power spectrum measurement as a function of tangential and radial wavenumbers we delineate the characteristic imprint of peculiar velocities. We use these to determine the growth rate of structure as a function of redshift in the range 0.4 < z < 0.8, including a data point at z=0.78 with an accuracy of 20%. Our growth rate measurements are a close match to the self-consistent prediction of the LCDM model. The WiggleZ Survey data will allow a wide range of investigations into the cosmological model, cosmic expansion and growth history, topology of cosmic structure, and Gaussianity of the initial conditions. Our calculation of the survey selection function will be released at a future date via our website wigglez.swin.edu.au.Comment: 21 pages, 22 figures, accepted for publication in MNRA

    Efficient Power Spectrum Estimation for High Resolution CMB Maps

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    Estimation of the angular power spectrum of the Cosmic Microwave Background (CMB) on a small patch of sky is usually plagued by serious spectral leakage, specially when the map has a hard edge. Even on a full sky map, point source masks can alias power from large scales to small scales producing excess variance at high multipoles. We describe a new fast, simple and local method for estimation of power spectra on small patches of the sky that minimizes spectral leakage and reduces the variance of the spectral estimate. For example, when compared with the standard uniform sampling approach on a 8 degree X 8 degree patch of the sky with 2% area masked due to point sources, our estimator halves the errorbars at l=2000 and achieves a more than fourfold reduction in errorbars at l=3500. Thus, a properly analyzed experiment will have errorbars at l=3500 equivalent to those of an experiment analyzed with the now standard technique with ~ 16-25 times the integration time.Comment: 22 pages, 15 figures; The TaperMaster package used in this paper will be made available in the near future at http://www.astro.princeton.edu/~sudeep/codes/tapermaster/tapermaster.htm
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