Covariant Quantum Fields on Noncommutative Spacetimes

A spinless covariant field $\phi$ on Minkowski spacetime \M^{d+1} obeys the relation $U(a,\Lambda)\phi(x)U(a,\Lambda)^{-1}=\phi(\Lambda x+a)$ where $(a,\Lambda)$ is an element of the Poincar\'e group \Pg and $U:(a,\Lambda)\to U(a,\Lambda)$ is its unitary representation on quantum vector states. It expresses the fact that Poincar\'e transformations are being unitary implemented. It has a classical analogy where field covariance shows that Poincar\'e transformations are canonically implemented. Covariance is self-reproducing: products of covariant fields are covariant. We recall these properties and use them to formulate the notion of covariant quantum fields on noncommutative spacetimes. In this way all our earlier results on dressing, statistics, etc. for Moyal spacetimes are derived transparently. For the Voros algebra, covariance and the *-operation are in conflict so that there are no covariant Voros fields compatible with *, a result we found earlier. The notion of Drinfel'd twist underlying much of the preceding discussion is extended to discrete abelian and nonabelian groups such as the mapping class groups of topological geons. For twists involving nonabelian groups the emergent spacetimes are nonassociative.Comment: 20 page

Mobile genetic elements in Clostridium difficile and their role in genome function.

Approximately 11% the Clostridium difficile genome is made up of mobile genetic elements which have a profound effect on the biology of the organism. This includes transfer of antibiotic resistance and other factors that allow the organism to survive challenging environments, modulation of toxin gene expression, transfer of the toxin genes themselves and the conversion of non-toxigenic strains to toxin producers. Mobile genetic elements have also been adapted by investigators to probe the biology of the organism and the various ways in which these have been used are reviewed

On-demand delivery of single DNA molecules using nanopipettes

Understanding the behavioral properties of single molecules or larger scale populations interacting with single molecules is currently a hotly pursued topic in nanotechnology. This arises from the potential such techniques have in relation to applications such as targeted drug delivery, early stage detection of disease, and drug screening. Although label and label-free single molecule detection strategies have existed for a number of years, currently lacking are efficient methods for the controllable delivery of single molecules in aqueous environments. In this article we show both experimentally and from simulations that nanopipets in conjunction with asymmetric voltage pulses can be used for label-free detection and delivery of single molecules through the tip of a nanopipet with “on-demand” timing resolution. This was demonstrated by controllable delivery of 5 kbp and 10 kbp DNA molecules from solutions with concentrations as low as 3 pM

Non-Pauli Effects from Noncommutative Spacetimes

Noncommutative spacetimes lead to nonlocal quantum field theories (qft's) where spin-statistics theorems cannot be proved. For this reason, and also backed by detailed arguments, it has been suggested that they get corrected on such spacetimes leading to small violations of the Pauli principle. In a recent paper \cite{Pauli}, Pauli-forbidden transitions from spacetime noncommutativity were calculated and confronted with experiments. Here we give details of the computation missing from this paper. The latter was based on a spacetime $\mathcal{B}_{\chi\vec{n}}$ different from the Moyal plane. We argue that it quantizes time in units of $\chi$. Energy is then conserved only mod $\frac{2\pi}{\chi}$. Issues related to superselection rules raised by non-Pauli effects are also discussed in a preliminary manner.Comment: 15 Pages, 1 Table, Full details and further developments of arXiv:1003.2250. This version is close to the one accepted by JHE

Musical borrowing and quotation in the twentieth and twenty-first centuries

How has quotation been used in the music of the past quarter century or so, and what has been its purpose? Can parallels be drawn between the motivations and interests of present- day composers, performers and musicians working in often widely divergent areas? What have been the effects of quotation on our understanding of contemporary music and how have critics and audiences responded to it? This special issue attempts to address these questions and engages with some of the most important concepts to have arisen in relation to musical quotation. It will set out to do this by taking a closer look at a number of recent styles, idioms, movements and practices, ranging from postmodernist appropriations of Mahler, via minimalism and postminimalism to contemporary music, opera, rock and hip-hop. Each article approaches quotation in today’s music from a different angle, offering theoretical perspectives, historical overviews, cultural critiques or analytical insights in order to question and challenge the often held belief that quotation has gone hand-in-hand with a perceived lack of creative endeavour or is somehow indicative of artistic mediocrity. On the contrary, some of the most exciting and innovative music composed during the last few decades have harnessed the principles of borrowing and quotation to very creative and imaginative ends

Rats distinguish between absence of events and lack of evidence in contingency learning.

The goal of three experiments was to study whether rats are aware of the difference between absence of events and lack of evidence. We used a Pavlovian extinction paradigm in which lights consistently signaling sucrose were suddenly paired with the absence of sucrose. The crucial manipulation involved the absent outcomes in the extinction phase. Whereas in the Cover conditions, access to the drinking receptacle was blocked by a metal plate, in the No Cover conditions, the drinking receptacle was accessible. The Test phase showed that in the Cover conditions, the measured expectancies of sucrose were clearly at a higher level than in the No Cover conditions. We compare two competing theories potentially explaining the findings. A cognitive theory interprets the observed effect as evidence that the rats were able to understand that the cover blocked informational access to the outcome information, and therefore the changed learning input did not necessarily signify a change of the underlying contingency in the world. An alternative associationist account, renewal theory, might instead explain the relative sparing of extinction in the Cover condition as a consequence of context change. We discuss the merits of both theories as accounts of our data and conclude that the cognitive explanation is in this case preferred

A Morphological and Lexical Study on Papuan Indonesian Dialect

Dialect is a variety of language that has uniqueness in phonology,morphology, syntax and vocabulary. One of the examples of dialect spoken inIndonesia is Papuan dialect. The uniqueness of Papuan Indonesian dialect can beseen in its morphology and vocabulary. Thus, this study was conducted to analyzethe word formation process and the lexical variation in Papuan Indonesian dialect. This study was a qualitative research. The data of this study were theutterances which contained linguistics items that mark the characteristics oruniqueness of Papuan Indonesian dialect. In doing the observation, the writer tooknotes on the relevant data from the subjects that contain morphological and lexicalvariation of PID utterances that are different from Standard BI. In data analysis,the writer classified the data in form of table and gave further explanationaccording to the word formation processes. The results of this study showed that there are seven word formationprocesses in the lexical variation of Papuan Indonesian dialect. They areborrowing, blending, coinage, compounding, clipping, conversion, and derivation.Coinage is the most dominant with twenty six words, followed by clipping with 7words, 6 compounding words, 4 conversion words, 3 blending word, 2 derivation,and the last is borrowing with 1 word. In conclusion, Papuan Indonesian dialect is a Bahasa Indonesia that isspoken by Papuan. It has uniqueness in the word formation process of some of thewords. There are words that are formed differently with standard BI. Based onYule's theory of word formation process, the writer found seven of them in PID.For further research on PID, the writer suggests to the next writer who isinterested in Papuan Indonesian dialect to analyze it from the syntax andsociolingusitics point of view

Numerical and experimental assessment of the modal curvature method for damage detection in plate structures

This paper is concerned with the use of numerically obtained modal curvatures for damage detection in both isotropic and composite laminated plates. Numerical simulations are carried out by using COMSOL Multiphysics as FEM solver of the governing equations, in which a Mindlin-Reissner plate model is assumed and defects are introduced as localized smoothed variations of the baseline (healthy) configuration. Experiments are also performed on steel and aluminum plates using scanning laser vibrometry. This study confirms that the central difference method greatly amplifies the measurement errors and its application leads to ineffective predictions for damage detection, even after denoising. As a consequence, different numerical techniques should be explored to allow the use of numerically obtained modal curvatures for structural health monitoring. Herein, the Savitzky-Golay filter (or least-square smoothing filter) is considered for the numerical differentiation of noisy data

Numerical and experimental assessment of the modal curvature method for damage detection in plate structures

Use of modal curvatures obtained from modal displacement data for damage detection in isotropic and composite laminated plates is addressed through numerical examples and experimental tests. Numerical simulations are carried out employing COMSOL Multiphysics as finite element solver of the equations governing the Mindlin-Reissner plate model. Damages are introduced as localized non-smooth variations of the bending stiffness of the baseline (healthy) configuration. Experiments are also performed on steel and aluminum plates using scanning laser vibrometry. The obtained results confirm that use of the central difference method to compute modal curvatures greatly amplifies the measurement errors and its application leads to unreliable predictions for damage detection, even after denoising. Therefore, specialized ad hoc numerical techniques must be suitably implemented to enable structural health monitoring via modal curvature changes. In this study, the Savitzky-Golay filter (also referred to as least-square smoothing filter) is considered for the numerical differentiation of noisy data. Numerical and experimental results show that this filter is effective for the reliable computation of modal curvature changes in plate structures due to defects and/or damages