1,750 research outputs found
Periodic Behavior of the Minimal Colijn-Plazzotta Rank for Trees with a Fixed Number of Leaves
No full textThe Colijn-Plazzotta ranking is a certain bijection between the unlabeled binary rooted trees and the positive integers, such that the integer associated with a tree is determined from the integers associated with the two immediate subtrees of its root. Letting a_n denote the minimal Colijn-Plazzotta rank among all trees with a specified number of leaves n, the sequence {a_n} begins 1, 2, 3, 4, 6, 7, 10, 11, 20, 22, 28, 29, 53, 56, 66, 67 (OEIS A354970). Here we show that a_n ∼ 2 [2^{P(log₂ n)}]ⁿ, where P varies as a periodic function dependent on {log₂ n} and satisfies 1.24602 < 2^{P(log₂ n)} < 1.33429
Pushing the Limits: A Search for the Lepton Flavour Violating Decay τ → 3μ within Heavy Flavour Jets with the Atlas Detector
No full textContains fulltext :
214940.pdf (Publisher’s version ) (Open Access)Radboud University, 05 maart 2020Promotores : Groot, N. de, Colijn, A.P.149 p
Factors Influencing Phytophthora ramorum Infectivity on Umbellularia californica and Testing of a Defoliation-Based Control Method
No full textThe primary foliar host for Phytophthora ramorum is Umbellularia californica (bay laurel), a tree species that serves as a reservoir for infections in California woodlands. I investigated environmental and pathogen-mediated influences on the incidence and severity of P. ramorum infection of U. californica as well as developing non-destructive means for controlling P. ramorum in woodlands.\ud
The distribution and abundance of P. ramorum in California is typically assessed by counting symptomatic hosts and confirmed by culturing the pathogen from field-collected samples. I hypothesized that the probability of a successful culture depends on the local environmental conditions where the field samples are collected. In 2010, an extensive culturing study was conducted within a previously established plot network in Sonoma County, where P. ramorum has been studied since 2003. I collected symptomatic leaf tissue for 424 trees in 153 plots randomly distributed within a 275 sq km region. Phytophothora ramorum was successfully cultured from 138 trees (32.5%) and collected from 71 plots (46.4%). Culture success was greatest in the southwest portion of the study area and lowest in the northeast. Culture success was positively related to topographic moisture index and field count of symptomatic leaves at the site and negatively related to average mean temperature at the site. These data show that culture success in the laboratory could be used as an indicator of inoculum load in the field. Studies that rely solely on culture success to determine pathogen presence should use caution in interpreting results, as they may overlook the possibility of false negatives.\ud
Additionally, I developed a live plant model to assess the validity of the commonly used detached leaf method for predicting interactions that occur between\ud
P. ramorum and foliar hosts. Specifically, I assessed infectivity of detached leaves and attached leaves from the same U. californica trees in a growth chamber and compared this to infectivity of detached leaves in an incubator. After seven days, lesions were scored. Mean infection score did not differ between detached leaves and attached leaves in the growth chamber. Detached leaves in the growth chamber and detached leaves in the incubator also did not differ significantly. Despite differences in light and humidity between the growth chamber and the incubator, no differences in infection score were found between any of the treatments. These results suggest that the detached leaf assay is a good indicator of infectivity in live trees.\ud
Finally, I examined controlled defoliation as an alternative to the current practice of managing P. ramorum through the destruction and removal of U. californica trees near symptomatic plants. Twenty-four U. californica seedlings were placed in six exclosures under infected canopies in Fairfield Osborn Preserve in February 2011. Two trees in each exclosure were sprayed in May and July 2011 with Ethephon, which releases ethylene upon decomposition, thereby inducing leaf abscission. Lesions were counted post treatment in January 2012. Leaves on the trees that received treatment developed significantly fewer lesions compared to the control group. Control saplings had 3.5 fold more infections than defoliated saplings. Defoliated saplings did experience excess lateral shooting, a side effect of Ethephon, as well as a dead zone at the crown. Further testing could determine the long-term effects of Ethephon on U. californica saplings and whether this dead zone is permanent or temporary. Ethephon does show promise as an alternate control method for P. ramorum.California Native Plant Societ
Psammodynastes pulverulentus
No full textPsammodynastes pulverulentus (H. Boie in F. Boie, 1827)— Erroneous. Common Mock Viper Singapore records. Psammodynastes pulverulentus — Iskandar & Colijn, 2001: 77.—Chan-ard et al., 2015: 215.— de Lang, 2017: 304. Remarks. Iskandar & Colijn (2001) listed Singapore as part of the distribution for P. pulverulentus, but we are unsure where they acquired the record from since there are no publications reporting it from Singapore. Chan-ard et al. (2015) likely confused P. pulverulentus with P. pictus by following Iskandar & Colijn (2001). However, Iskandar & Colijn (2001) listed both species as occurring in Singapore in their checklist. Psammodynastes pulverulentus covers a broad geographic distribution from northeastern India, Nepal, Bhutan, and Bangladesh east to Myanmar, Thailand, Cambodia, Vietnam, Laos, China, Hong Kong, and Taiwan, and south to Peninsular Malaysia, East Malaysia, Indonesia, and Philippines (Wallach et al. 2014). LKCNHM & NHMUK Museum specimens. No specimens. Additional Singapore museum specimens. No specimens. Family Pareidae Romer, 1956 (1 species) Genus Pareas Wagler, 1830 (1 species)Published as part of Figueroa, Alex, Low, Martyn E. Y. & Lim, Kelvin K. P., 2023, Singapore's herpetofauna: updated and annotated checklist, history, conservation, and distribution, pp. 1-378 in Zootaxa 5287 (1) on page 278, DOI: 10.11646/zootaxa.5287.1.1, http://zenodo.org/record/796031
Oratie, of uutspraecke van het recht der Nederlandtsche oorloge teghen Philippum coningh van Spaengien, aen de [...] vorsten van Kerstenrijck van eenen Nederlandschen edelman ghedaen.
No full textVingerafdruk: 160804 - b1 A2 we : b2 F3 ren$Verpakt met de steun van Fonds Inbev-Latour (2010-2012)Herkomst: Vignet Isaac MeulmanTiele, P. A. Bibliotheek van Nederlandsche pamfletten. Verzameling Frederik Muller ; 699Europeana-GoogleBooksLammens, Pierre Philippe Constan
Introduction to the Assessment—Characteristics of the Region
No full textThis scene-setting chapter provides the basis for the climate change-related assessments presented in later chapters of this book. It opens with an overview of the geography, demography and major human activities of the North Sea and its boundary countries. This is followed by a series of sections describing the geological and climatic evolution of the North Sea basin, the topography and hydrography of the North Sea (i.e. boundary forcing; thermohaline, wind-driven and tidally-driven regimes; and transport processes), and its current atmospheric climate (focussing on circulation, wind, temperature, precipitation, radiation and cloud cover). This physical description is followed by a review of North Sea ecosystems. Marine and coastal ecosystems are addressed in terms of ecological habitats, ecological dynamics, and human-induced stresses representing a threat (i.e. eutrophication, harmful algal blooms, offshore oil and gas, renewable energy, fisheries, contaminants, tourism, ports, non-indigenous species and climate change). Terrestrial coastal range vegetation is addressed in terms of natural vegetation (salt marshes, dunes, moors/bogs, tundra and alpine vegetation, and forests), semi-natural vegetation (heathlands and grasslands), agricultural areas and artificial surfaces
L3 measurement of the lepton lifetime
No full textThe tau lepton lifetime is measured with the L3 detector at LEP. For the analysis presented here tau pairs produced during 1994 and 1995 around the Z pole are used. The measurement is done by a decay length method for the 3-prong tau decays and by an impact parameter analysis for the 1-prong decays. From the data 6620 3-prong decays are selected, from which a lifetime of tau /sub tau /=291.4+or-3.9 (stat) +or-2.0 (syst) fs is determined. The impact parameter analysis on 58 656 1-prong decays results in a lifetime of tau /sub tau /=290.5+or-2.7 (stat)+or-2.9 (syst) fs. Combination with our previous results gives tau /sub tau /=291.7+or-2.0 (stat)+or-1.8 (syst) fs. These numbers are preliminary. (6 refs)
Investigation into a five-dimensional unified field theory
No full textBibliography: p. 45-46.This title is not available online. Access options are:
- consulting the copy from Archives in our reading room in person - https://asc.ucalgary.ca/visiting/
- borrowing a circulating copy from the Library catalogue – https://ucalgary.primo.exlibrisgroup.com/discovery/search?vid=01UCALG_INST:UCALGARY&lang=e
A new Poa (Gramineae) from New Guinea
No full textMonostachya oreoboloides auct. non Hitchc.: Steen. in Colijn, Naar de eeuwige sneeuw van tropisch Nederland (1937) 275; Veldk. in Hope et al., Eq. Glac. N. G. (1976) 158, pro Wissel 63.
P. callosa auct. non Stapf: Veldk. in Hope et al., Eq. Glac. N. G. (1976) 158, pro ANU 10967, Raynal 17519
Evaporative CO2 heat transfer measurements for cooling systems of particle physics detectors
No full textPaper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.A major challenge in particle physics detectors is to transport the heat developed in their electronics to the outside world. Particle detectors require a minimum of material in order not to disturb accurate measurements of particle trajectories. CO, has superior behavior in small diameter- low material - tubes, although detailed experimental data are lacking. Understanding the behavior of evaporative C02 cooling in small diameter tubing is
therefore of large interest for future detector cooling developments.At the Dutch Institute for Subatomic Physics, Nikhef, we are developing an automated CO, test set-up able to scan the full phase space of mass fluxes, heat fluxes, vapor quality and temperature. A wide range of tube diameters (0.5 to 4mm) will be explored and data will be compared to the available models.In this paper we will present the test setup and the first measurements of heat transfer, pressure drop, and dry-out behavior at room temperature. Lower evaporation temperatures down to -50°C will be explored in a later stage after an upgrade of the research plant.ej201
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