Controlling Several Atoms in a Cavity

We treat control of several two-level atoms interacting with one mode of the electromagnetic field in a cavity. This provides a useful model to study pertinent aspects of quantum control in infinite dimensions via the emergence of infinite-dimensional system algebras. Hence we address problems arising with infinite-dimensional Lie algebras and those of unbounded operators. For the models considered, these problems can be solved by splitting the set of control Hamiltonians into two subsets: The first obeys an abelian symmetry and can be treated in terms of infinite-dimensional Lie algebras and strongly closed subgroups of the unitary group of the system Hilbert space. The second breaks this symmetry, and its discussion introduces new arguments. Yet, full controllability can be achieved in a strong sense: e.g., in a time dependent Jaynes-Cummings model we show that, by tuning coupling constants appropriately, every unitary of the coupled system (atoms and cavity) can be approximated with arbitrarily small error

Sport Participation Influences Perceptions of Mate Characteristics

Sport provides a context in which mate choice can be facilitated by the display of athletic prowess. Previous work has shown that, for females, team sport athletes are more desirable as mates than individual sport athletes and non-participants. In the present study, the perceptions of males and females were examined regarding potential mates base on sport participation. It was predicted that team sport athletes would be more positively perceived than individual sport athletes and non-participants by both males and females. A questionnaire, a photograph, and manipulated descriptions were used to gauge perceptual differences with respect to team sport athletes, individual sport athletes, and extracurricular club participants for 125 females and 119 males from a Canadian university. Both team and individual sport athletes were perceived as being less lazy, more competitive, and healthier than non-participants by both males and females. Interestingly, females perceived male athletes as more promiscuous than non-athletes, which upholds predictions based on previous research indicating (a) athletes have more sexual partners than non-athletes, and (b) females find athletes more desirable as partners than nonparticipants. Surprisingly, only males perceived female team sport athletes as more dependable than non-participants, and both team and individual sport athletes as more ambitious. This raises questions regarding the initial hypothesis that male team athletes would be perceived positively by females because of qualities such as the ability to cooperate, likeability, and the acceptance of responsibilities necessary for group functioning. Future studies should examine similar questions with a larger sample size that encompasses multiple contexts, taking into account the role of the social profile of sport in relation to mate choice and perception

Effect of reduced chromatin gene expression on the epigenetically regulated maize gene, Pl-Blotched [abstract]

Abstract only availableEukaryotes can regulate gene expression using epigenetic mechanisms that involve changes in chromatin packing. Open, loosely packed chromatin is accessible and actively transcribed, whereas closed, tightly packed chromatin is less accessible and associated with gene silencing. Many studies have furnished information about how covalent modifications of the DNA and histone components of chromatin can alter its structure. However, much remains to be learned about regulation of those changes. To address this problem, we are analyzing the expression of an epigenetically-regulated gene, Pl-Blotched, that controls the synthesis of purple anthocyanin pigments in maize. The maize anthocyanin pathway offers an excellent system for studying gene control mechanisms, because the genetics is well understood and pigment levels are an accurate reporter for activity of the underlying genes. Pl-Blotched has a variegated phenotype that is associated with a unique pattern of DNA methylation and more closed chromatin structure than usual. To understand how these epigenetic features are controlled, we have introduced Pl-Blotched into lines with reduced expression of genes involved in DNA methylation, histone acetylation and chromatin remodeling. By measuring and comparing pigment levels in plants with and without the chromatin-gene mutations, we can gain insights about which chromatin genes might be involved in controlling the epigenetic state of Pl-Blotched. Our results thus far implicate multiple classes of chromatin genes--including several involved in histone acetylation--as regulators of Pl-Blotched expression.Life Sciences Undergraduate Research Opportunity Progra

Runes and metrics

The paper argues that the metrical status of the older runic inscriptions has been partly overestimated in the research literature, and that it is more likely to account for traditions of elevated, stylized prose instead. In the present discussion, three diagnostic criteria will be assessed: 1. the syllable-count, 2. quantity-sensitivity and 3. the structural complexity of the alliterative scheme. The fine divide between style and metrics will be exemplified by inscriptions such as Noleby, Sjælland II, Tjurkö I and last but not least, the StentoftenâBjörketorp group. In conclusion, the Germanic long-line represents the only true metrical form within the older runic corpus, whereas the bulk of the Early Runic inscriptions are identified as artefacts of elevated prose style with typical features of formulaic diction

From pagan charms to pious prayers? A case study of two runic formulas

Emnet for dette bidraget er to runeformler fra ulike tidsepoker. De er strukturelt nokså likt gjennomført ved enderim og “[v]ekslende initialer med faste repetisjoner” (Nordby 2018: 109). Den ene er den velkjente þistill-mistill-kistill-formelen, som først opptrer på den danske Gørlevsteinen rundt 800–850 e.Kr., den andre er den yngre horn-þorn-korn-formelen, som er ristet inn i kalkpuss i to gotlandske kirker og på en blyamulett fra Kællingeby. Denne type formler kobles gjerne til en opplæringskontekst, særlig horn-þorn-korn. Artikkelen argumenterer for en symbiose mellom hedenske og kristne allegorier som kommer til syne i ulike kontekster. Det argumenteres for en interaksjon mellom folkemagi og kristne bønner som tar i bruk både hedenske og kristne virkemidler. Den prototypiske vernefunksjonen av de to formlene kommer tydelig fram på amulettinnskrifter fra middelalderen, jf. þistill-mistill-kistill-formelen på Vedslet-sandsteinamuletten (DR 57) og horn-þorn-korn-formelen på Kællingeby-blyamuletten (DK Bh 20).publishedVersio

Board games of the Vikings – From hnefatafl to chess

The relationship between the Viking game hnefatafl and the new board game of chess is an intricate one, made all the more so by the fact that both are described by the same term: tafl. In this paper, I focus both on the archaeological and the literary evidence for the two board games and the diagnostic features that set them apart. At the outset, the famous reference to tafl by Kali Kolsson, the future Earl Rǫgnvaldr of Orkney, is highlighted, and it is argued that Kali actually meant skáktafl, i.e. chess, when he used this term. The Ballinderry board from Ireland and the Ockelbo rune-stone from Sweden are subsequently presented as typical examples of the Viking game hnefatafl. Part of the discussion dwells on the eddic poem Vǫlospá and the symbolic value of the golden gaming pieces, which, I argue, reflect the Nordic memory culture of the Viking Age. In what follows, the most important evidence for chess in the North is addressed: the Lewis chessmen. A consideration of all these various forms of evidence leads to the conclusion that Vikings played a key role in the reception and reshaping of the game of chess in Scandinavia and beyond