1,356,190 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
Charting the Pandemic with Data Modelling — with Caroline Colijn
No full textSFU Mathematics professor Caroline Colijn joins host Am Johal to talk about the role of data modelling in the response to COVID-19. Caroline holds the Canada 150 Research Chair in Mathematics for Infection, Evolution and Public Health, and works at the intersection of mathematics and public health, with a particular focus on the spread and evolution of infectious diseases.She has been working alongside colleagues since the beginning of the pandemic, using data to mathematically model the trajectory of COVID-19 and to inform public policy. In this interview, she gives a brief overview of how we\u27ve arrived at this point in the pandemic here in BC. They discuss the potential benefits of prioritizing high-contact workers in the rollout of vaccines, variants of concern in BC, and what data tells us about COVID-19 spread in the weeks and months to come
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
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Bureauonderzoek en inventariserend veldonderzoek d.m.v. boringen Tussen de Leijen te Gilze en Rijen: Antea Group Archeologie 2019/10
No full textIn januari 2019 heeft Antea Group een archeologisch onderzoek uitgevoerd voor een plangebied ‘Tussen de Leijen’ in Rijen, gemeente Gilze en Rijen. Het onderzoek heeft bestaan uit een archeologisch bureau- en booronderzoek (verkennende fase).
Bureauonderzoek Het plangebied ligt in het vigerende bestemmingsplan ‘Buitengebied’ uit 2013. De voorgenomen ontwikkelingen passen niet binnen dit bestemmingsplan. Om de voorgenomen herontwikkeling mogelijk te maken is het opstellen van een nieuw bestemmingsplan vereist. Archeologie is hiervoor één van de deelonderzoeken.
In het vigerende bestemmingsplan is voor het zuidelijke deel van het plangebied een dubbelbestemming ‘waarde – archeologie’ opgenomen. Voor gebieden met deze aanduiding geldt dat archeologisch onderzoek verplicht is bij bodemingrepen die dieper reiken dan 0,4 m – mv en/of een oppervlakte van meer dan 100 m2 beslaan. Deze dubbelbestemming volgt uit de archeologische beleidskaart van de gemeente Gilze en Rijen (zie paragraaf 2.3.1). Op de genoemde beleidskaart is het noordelijk deel van onderhavig plangebied opgenomen als een gebied met een lage verwachtingswaarde. De archeologische dubbelbestemming ontbreekt hier dan ook in het vigerend bestemmingsplan.
Het plangebied heeft voor het grootste gedeelte een lage archeologische verwachting op resten vanaf het paleolithicum tot en met de nieuwe tijd. Deze lage verwachting hangt samen met de aanwezigheid van veldpoldzolgronden, die vooral voorkomen in lage en natte gebieden. Deze gebieden waren in het verleden niet aantrekkelijk voor bewoning. In het zuiden van het plangebied was een dalvormige laagte aanwezig. Rondom deze dalvormige laagte geldt een middelhoge verwachting op archeologische resten vanaf het paleolithicum tot en met de middeleeuwen. Deze locaties werden juist gezien als voorkeurslocatie voor bewoning, vanwege de grote diversiteit in de biotoop.
Veldonderzoek In het plangebied is sprake van een moerige eerdgrond met zanddek in een twaalftal boringen. In twee boringen is een A-C profiel waargenomen en in alle overige boringen is tussen de A en C-horizont sprake van een geroerde AC horizont. De bodem is daarmee in het grootste deel van het plangebied verstoord tot voorbij het potentieel archeologisch vlak. De moerige eerdgrond bevestigt de aanwezigheid van de dalvormige laagte. Verondersteld mag worden dat het hier gaat om een laagte tussen twee welvingen waarbij mogelijk maar niet noodzakelijkerwijs de laagte ook als een ooit actief beekdal moet worden geïnterpreteerd. Puntvondsten als kano’s en voordes zijn hiermee niet waarschijnlijk. Een aanwijzing hiervoor is het vlekkerige karakter van de aangetroffen moerige laag.
Advies Op grond van de aangetroffen bodemopbouw acht Antea Group de kans op het aantreffen van archeologische vindplaatsen in het plangebied zeer klein. Het advies luidt dan ook om het plangebied vrij te geven zonder nader archeologisch onderzoek uit te voeren. Dit betreft een selectieadvies; het nemen van een selectiebesluit is voorbehouden aan de bevoegde overheid, in deze de gemeente Gilze en Rijen. Dit rapport is voorgelegd aan de bevoegde overheid. Op 26-9-2019 is het rapport beoordeeld. In deze versie van de rapportage zijn deze opmerkingen verwerkt
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Translating Poetic Capital in 15th-Century Brussels: From Amé de Montgesoie’s “Pas de la Mort” to Colijn Caillieu’s “Dal sonder Wederkeeren”
No full textDispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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