2,744 research outputs found
How the Ji’kmaqn Came to Spiro: Possible Additions to the Inventory of Sound-Making Instruments Depicted in the Spiro Engravings
While doing research on turtle shell rattles the author stumbled onto a photograph of a rare and unusual idiophone whose exact likeness appears twice in one of the engraved shell images from Spiro. This paper describes the instrument and the Spiro image and discusses how an instrument currently found only in the Maritime Provinces of Canada may have come to be portrayed on a marine shell cup found at Spiro
Seventy years of sex education in Health Education Journal: a critical review
This paper examines key debates and perspectives on sex education in Health Education Journal (HEJ), from the date of the journal’s first publication in March 1943 to the present day. Matters relating to sexuality and sexual health are revealed to be integral to HEJ’s history. First published as Health and Empire (1921 – 1942), a key purpose of the journal since its inception has been to share information on venereal disease and its prevention within the UK and across the former British Empire. From 1943 to the present day, discussions on sex education in the newly-christened HEJ both reflect and respond to evolving socio-cultural attitudes towards sexuality in the UK. Changing definitions of sex education across the decades are examined, from the prevention of venereal disease and moral decline in war-time Britain in the 1940s, to a range of responses to sexual liberation in the 1960s and 1970s; from a focus on preventing sexually-transmitted infections, teenage pregnancy and HIV in the 1980s, to the provision of sexual health services alongside sex education in the 2000s. Over the past 70 years, a shift from prevention of pre-marital sexual activity to the management of its outcomes is apparent; however, while these changes over time are notable, perhaps the most striking findings of this review are the continuities in arguments for and against the discussion of sexual issues. After more than 70 years of debate, it would seem that there is little consensus concerning motivations for and the content of sex education
Reissner-Nordstrom and charged gas spheres
The main point of this paper is a suggestion about the proper treatment of
the photon gas in a theory of stellar structure and other plasmas. This problem
arises in the study of polytropic gas spheres, where we have already introduced
some innovations. The main idea, already advanced in the contextof neutral,
homogeneous, polytropic stellar models, is to base the theory firmly on a
variational principle. Another essential novelty is to let mass distribution
extend to infinity, the boundary between bulk and atmosphere being defined by
an abrupt change in the polytropic index, triggered by the density. The logical
next step in this program is to include the effect of radiation, which is a
very significant complication since a full treatment would have to include an
account of ionization, thus fieldsrepresenting electrons, ions, photons,
gravitons and neutral atoms as well. In way of preparation, we consider models
that are charged but homogeneous, involving only gravity, electromagnetism and
a single scalar field that represents both the mass and the electric charge; in
short, anon-neutral plasma. While this work only represents a stage in the
development of a theory of stars, without direct application to physical
systems, it does shed some light on the meaning of the Reissner-Nordstrom
solution of the modified Einstein-Maxwell equations., with an application to a
simple system.Comment: 19 pages, plain te
A Study of the Relationship of Various Grades of Fresh and Canned Vegetables. II. Canned tomato juice
Taming the Runaway Problem of Inflationary Landscapes
A wide variety of vacua, and their cosmological realization, may provide an
explanation for the apparently anthropic choices of some parameters of particle
physics and cosmology. If the probability on various parameters is weighted by
volume, a flat potential for slow-roll inflation is also naturally understood,
since the flatter the potential the larger the volume of the sub-universe.
However, such inflationary landscapes have a serious problem, predicting an
environment that makes it exponentially hard for observers to exist and giving
an exponentially small probability for a moderate universe like ours. A general
solution to this problem is proposed, and is illustrated in the context of
inflaton decay and leptogenesis, leading to an upper bound on the reheating
temperature in our sub-universe. In a particular scenario of chaotic inflation
and non-thermal leptogenesis, predictions can be made for the size of CP
violating phases, the rate of neutrinoless double beta decay and, in the case
of theories with gauge-mediated weak scale supersymmetry, for the fundamental
scale of supersymmetry breaking.Comment: 31 pages, including 3 figure
Successful Flash-Cooling of Xenon Derivatized Myoglobin Crystals
This paper demonstrates for the first time a method for preparing cryocooled xenon-derivatized protein crystals. The method is based upon the hypothesis and subsequent observation that the diffusion of a xenon atom from a tight binding site following depressurization occurs on a timescale of minutes. We have observed significant changes in diffraction intensities from myoglobin crystals for up to 5 min following depressurization from 1 MPa of xenon. In accordance with this observation, a xenon-derivatized myoglobin crystal was cryocooled at ~95 K within 20 s of complete depressurization. A crystallographic data set was then collected to 2.0 Å resolution and isomorphous and anomalous difference Patterson maps revealed the presence of a well ordered xenon site with an occupancy of approximately 0.5. Phasing statistics for this site were of good quality and demonstrate the practicality of this method. The ability to cryocool xenon-derivatized crystals will make this heavy-atom substitution method even more useful for single-isomorphous-replacement and multiple-isomorphous-replacement phasing of macromolecules
Evolving Spatially Aggregated Features from Satellite Imagery for Regional Modeling
Satellite imagery and remote sensing provide explanatory variables at
relatively high resolutions for modeling geospatial phenomena, yet regional
summaries are often desirable for analysis and actionable insight. In this
paper, we propose a novel method of inducing spatial aggregations as a
component of the machine learning process, yielding regional model features
whose construction is driven by model prediction performance rather than prior
assumptions. Our results demonstrate that Genetic Programming is particularly
well suited to this type of feature construction because it can automatically
synthesize appropriate aggregations, as well as better incorporate them into
predictive models compared to other regression methods we tested. In our
experiments we consider a specific problem instance and real-world dataset
relevant to predicting snow properties in high-mountain Asia
Schr\"odinger Deformations of AdS_3 x S^3
We study Schr\"odinger invariant deformations of the AdS_3 x S^3 x T^4 (or
K3) solution of IIB supergravity and find a large class of solutions with
integer and half-integer dynamical exponents. We analyze the supersymmetries
preserved by our solutions and find an infinite number of solutions with four
supersymmetries. We study the solutions holographically and find that the dual
D1-D5 (or F1-NS5) CFT is deformed by irrelevant operators of spin one and two.Comment: 23 page
An unfolding signifier: London's Baltic Exchange in Tallinn
In the summer of 2007 an unusual cargo arrived at Muuga and Paldiski harbors outside Tallinn. It consisted of nearly 50 containers holding over 1,000 tons of building material ranging from marble columns, staircases and fireplaces, to sculpted allegorical figures, wooden paneling and old-fashioned telephone booths. They were once part of the Baltic Exchange in the City of London. Soon they will become facets of the landscape of Tallinn. The following article charts this remarkable story and deploys this fragmented monument to analyze three issues relating to the Estonian capital: the relocation of the ‘Bronze Soldier’, the demolition of the Sakala Culture Center, and Tallinn’s future role as European Cultural Capital in 2011
Opening the black box of mixed-metal TMP metallating reagents : direct cadmation or lithium-cadmium transmetallation?
Designed to remove some of the mystery surrounding mixed-metal TMP (2,2,6,6-tetramethylpiperidide) metallating reagents, this study examines in detail "LiCd(TMP)(3)'' in its own right. Previously established as an excellent "cadmating'' (Cd-H exchange) reagent towards a wide variety of aromatic substrates, "LiCd(TMP)(3)'' has been investigated by H-1, C-13 and Cd-113 NMR studies as well as by DOSY NMR spectroscopy. This evidence puts a question mark against its ate formulation implying it exists in THF solution as two independent homometallic amides. Exploring the reactivity of "LiCd(TMP)(3)'' with anisole as a test substrate, both experimentally by NMR studies and theoretically by DFT studies suggests a two-step lithiation/transmetallation process in which the initially formed ortho-lithiated species undergoes a reaction with Cd(TMP)(2) to form new Cd-C and Li-N bonds. For completeness, the homometallic cadmium component Cd(TMP)(2) has been comprehensively characterised for the first time including a crystal structure determination revealing a near-linear N-Cd-N arrangement
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