262 research outputs found
Prismatic decompositions and rational -spectra
We study the tensor-triangular geometry of the category of rational
-spectra for a compact Lie group . In particular, we prove that this
category can be naturally decomposed into local factors supported on individual
subgroups, each of which admits an algebraic model. This is an important step
and strong evidence towards the third author's conjecture that the category of
rational -spectra admits an algebraic model for all compact Lie groups.
To facilitate these results, we relate topological properties of the
associated Balmer spectrum to structural features of the group and the
category of rational -spectra. A key ingredient is our presentation of the
spectrum as a Priestley space, separating the Hausdorff topology on conjugacy
classes of closed subgroups of from the cotoral ordering. We use this to
prove that the telescope conjecture holds in general for rational -spectra,
and we determine exactly when the Balmer spectrum is Noetherian. In order to
construct the desired decomposition of the category, we develop a general
theory of `prismatic decompositions' of rigidly-compactly generated
tensor-triangulated categories, which in favourable cases gives a series of
recollements for reconstructing the category from local factors over individual
points of the spectrum.Comment: 61 pages; all comments welcome
Support for graphicacy: a review of textbooks available to accounting students
This Teaching Note reports on the support available in textbooks for graphicacy that will help students understand the complexities of graphical displays. Graphical displays play a significant role in financial reporting, and studies have found evidence of measurement distortion and selection bias. To understand the complexities of graphical displays, students need a sound understanding of graphicacy and support from the textbooks available to them to develop that understanding. The Teaching Note reports on a survey that examined the textbooks available to students attending two Scottish universities. The support of critical graphicacy skills was examined in conjunction with textbook characteristics. The survey, which was not restricted to textbooks designated as required reading, examined the textbooks for content on data measurement and graphical displays. The findings highlight a lack of support for graphicacy in the textbooks selected. The study concludes that accounting educators need to scrutinize more closely the selection of textbooks and calls for more extensive research into textbooks as a pedagogic tool
Torsion models for tensor-triangulated categories: the one-step case
Given a suitable stable monoidal model category and a
specialization closed subset of its Balmer spectrum one can produce a Tate
square for decomposing objects into the part supported over and the part
supported over spliced with the Tate object. Using this one can show that
is Quillen equivalent to a model built from the data of local
torsion objects, and the splicing data lies in a rather rich category. As an
application, we promote the torsion model for the homotopy category of rational
circle-equivariant spectra from [18] to a Quillen equivalence. In addition, a
close analysis of the one step case highlights important features needed for
general torsion models which we will return to in future work.Comment: 35 pages, minor changes in the introductio
Nurturing the young shoots of talent: Using action research for exploration and theory building
This is an Author's Accepted Manuscript of an article published in European Early Childhood Education Research Journal, 19(4), 433-450, 2011, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/1350293X.2011.623515.This paper reports the outcomes of a set of action research projects carried out by teacher researchers in 14 local education authorities in England, working collaboratively with university tutors, over a period of three years. The common aim of all the projects was to explore practical ways of nurturing the gifts and talents of children aged fourâseven years. The project was funded by the Department of Education and Skills in England as part of the government's gifted and talented programme. The project teachers felt that their understanding of issues relating to nurturing the gifts and talents of younger children was enhanced through their engagement in the project. It was possible to map the findings of the projects to the English government's National Quality Standards for gifted and talented education which include: (1) identification; (2) effective provision in the classroom; (3) enabling curriculum entitlement and choice; (4) assessment for learning; (5) engaging with community, families and beyond. The findings are also analysed within the framework of good practice in educating children in the first years of schooling. Participating practitioners felt that action research offered them a suitable methodology to explore the complexity of the topic of giftedness through cycles of planning, action and reflection and personal theory building
Application of direct bioautography and SPME-GC-MS for the study of antibacterial chamomile ingredients
The isolation and characterization of antibacterial chamomile components were performed by the use of direct bioautography and solid phase microextraction (SPME)-GC-MS. Four ingredients, active against Vibrio fischeri, were identified as the polyacetylene geometric isomers cis- and trans-spiroethers, the coumarin related herniarin, and the sesquiterpene alcohol (-)-alpha-bisabolol
Periodic points in random substitution subshifts
We study various aspects of periodic points for random substitution subshifts. In order to do so, we introduce a new property for random substitutions called the disjoint images condition. We provide a procedure for determining the property for compatible random substitutionsârandom substitutions for which a well-defined abelianisation exists. We find some simple necessary criteria for primitive, compatible random substitutions to admit periodic points in their subshifts. In the case that the random substitution further has disjoint images and is of constant length, we provide a stronger criterion. A method is outlined for enumerating periodic points of any specified length in a random substitution subshift
Area-level poverty and preterm birth risk: A population-based multilevel analysis
<p>Abstract</p> <p>Background</p> <p>Preterm birth is a complex disease with etiologic influences from a variety of social, environmental, hormonal, genetic, and other factors. The purpose of this study was to utilize a large population-based birth registry to estimate the independent effect of county-level poverty on preterm birth risk. To accomplish this, we used a multilevel logistic regression approach to account for multiple co-existent individual-level variables and county-level poverty rate.</p> <p>Methods</p> <p>Population-based study utilizing Missouri's birth certificate database (1989â1997). We conducted a multilevel logistic regression analysis to estimate the effect of county-level poverty on PTB risk. Of 634,994 births nested within 115 counties in Missouri, two levels were considered. Individual-level variables included demographics factors, prenatal care, health-related behavioral risk factors, and medical risk factors. The area-level variable included the percentage of the population within each county living below the poverty line (US census data, 1990). Counties were divided into quartiles of poverty; the first quartile (lowest rate of poverty) was the reference group.</p> <p>Results</p> <p>PTB < 35 weeks occurred in 24,490 pregnancies (3.9%). The rate of PTB < 35 weeks was 2.8% in counties within the lowest quartile of poverty and increased through the 4<sup>th </sup>quartile (4.9%), p < 0.0001. High county-level poverty was significantly associated with PTB risk. PTB risk (< 35 weeks) was increased for women who resided in counties within the highest quartile of poverty, adjusted odds ratio (<sub>adj</sub>OR) 1.18 (95% CI 1.03, 1.35), with a similar effect at earlier gestational ages (< 32 weeks), <sub>adj</sub>OR 1.27 (95% CI 1.06, 1.52).</p> <p>Conclusion</p> <p>Women residing in socioeconomically deprived areas are at increased risk of preterm birth, above other underlying risk factors. Although the risk increase is modest, it affects a large number of pregnancies.</p
Breaking the Double Impasse: Securing and Supporting Diverse Housing Tenures in the United States
What might be described as a double impasse characterizes debate on U.S. housing tenure with advocates fighting for rental or ownership housing on one side and Third Way or mixed-tenure solutions on the other. Breaking this impasse requires disengaging from conceptions of an idealized form of tenure and instead advocating making virtually all tenures as secure and supported as possible, so that diverse households are able to live in homes that best fit their changing needs over their life cycles. This essay (a) presents data on the variety of tenures in the United States; (b) conveys a new two-dimensional map of tenure according to their degrees of control and potential for wealth-building; and (c) shows how U.S. institutions shape their risks and subsidies. Most U.S. tenures are at least somewhat risky, including those that receive the greatest federal subsidies. A new housing system is needed to secure and support as many tenures as possible
Chemical composition and antibacterial activity of essential oils from the medicinal plant Mentha cervina L. grown in Portugal
Mentha cervina is a medicinal plant traditionally
used in Portugal in folk medicine, in different gastric
disorders and inflammations of the respiratory tract. In
order to validate those traditional uses, M. cervina essential
oils (EOs) were characterized by GC and GCâMS and their
antimicrobial activity was tested against 23 bacterial strains
(including multiresistant strains). The EOs were dominated
by the monoterpenes pulegone (52â75%), isomenthone
(8â24%), limonene (4â6%), and menthone (1â2%). The
antibacterial activity of these EOs was compared to that of
the main components standards. The most effective antibacterial
activity was expressed by the EOs against the
Gram-negative bacteria, Escherichia coli and Acinetobacter
baumanni, with MIC values of 1 mg/ml. The EOs complex mixtures were more active than the individual
aromatic components supporting the hypothesis that the
EOs antibacterial activity is a function of the synergistic
effect of their different aromatic components. These results
show the potential role of M. cervina EOs as antibacterial
agents and validate the traditional use of this plant
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