Initial Conditions for Non-Canonical Inflation

We investigate the dynamics of homogeneous phase space for single-field models of inflation. Inflationary trajectories are formally attractors in phase space, but since in practice not all initial conditions lead to them, some degree of fine tuning is required for successful inflation. We explore how the dynamics of non-canonical inflation, which has additional kinetic terms that are powers of the kinetic energy, can play a role in ameliorating the initial conditions fine tuning problem. We present a qualitative analysis of inflationary phase space based on the dynamical behavior of the scalar field. This allows us to construct the flow of trajectories, finding that trajectories generically decay towards the inflationary solution at a steeper angle for non-canonical kinetic terms, in comparison to canonical kinetic terms, so that a larger fraction of the initial-conditions space leads to inflation. Thus, non-canonical kinetic terms can be important for removing the initial conditions fine-tuning problem of some small-field inflation models.Comment: 15 pages, 9 figure

Attractive Lagrangians for Noncanonical Inflation

Treating inflation as an effective theory, we expect the effective Lagrangian to contain higher-dimensional kinetic operators suppressed by the scale of UV physics. When these operators are powers of the inflaton kinetic energy, the scalar field can support a period of noncanonical inflation which is smoothly connected to the usual slow-roll inflation. We show how to construct noncanonical inflationary solutions to the equations of motion for the first time, and demonstrate that noncanonical inflation is an attractor in phase space for all small- and large-field models. We identify some sufficient conditions on the functional form of the Lagrangian that lead to successful noncanonical inflation since not every Lagrangian with higher-dimensional kinetic operators can support noncanonical inflation. This extends the class of known viable Lagrangians and excludes many Lagrangians which do not work.Comment: 39 pages, 9 figures. v2. Fixed typos, added reference, small changes to examples; v3. Added discussion of field redefinitions, added references, matches published versio

Construction individuelle, acculturation mathématique et communauté scolaire

Nous distinguons d'abord l'approche traditionnelle en enseignement des mathématiques, typique des classes dont le fonctionnement s'appuie sur l'utilisation de manuels, et l'approche « investigative » mise en oeuvre dans des classes dont le fonctionnement est compatible avec la perspective constructiviste. Nous mettons ensuite l'accent sur cette approche « investigative » et analysons les tensions théoriques et pragmatiques qu'elle suscite en relation avec une conception de l'apprentissage des mathématiques conçu à la fois comme processus actif de construction individuelle et un processus d'acculturation. Une attention particulière est accordée aux façons dont le constructivisme et les théories socioculturelles abordent cet aspect. Nous traitons enfin du développement de certaines activités pédagogiques mises en oeuvre dans des classes de mathématiques à fonctionnement « investigatif ».We first distinguish between the school mathematics tradition typically established in textbook-based classrooms and the inquiry mathematics tradition established in classrooms where instruction is compatible with constructivism. We then focus on the inquiry mathematics tradition and consider the theoretical and pragmatic tensions inherent in the view that mathematical learning is both a process of active individual construction and a process of acculturation. Particular attention is given to the ways in which both constructivist and sociocultural theorists address this issue. Finally, we discuss the development of instructional activities for inquiry mathematics classrooms.Primero distinguimos el enfoque tradicional de las matematicas tipicas de las clases, cuyo funcionamiento se apoya en la utilization de manuales, del enfoque "investigativo" utilizado en las clases, cuyo funcionamiento es compatible con la perspectiva construccionista. Luego acentuamos este enfoque "investigativo" y analizamos las tensiones teóricas y pragmaticas que surgen al mirar la conception del aprendizaje de las matematicas que la apoya, tratandose a la vez de un proceso activo de construction individual y de un proceso de aculturacion. Se acuerda una atencion especial a las formas en que el construccionismo y las teorias socioculturales abordan este aspecto. Finalmente tratamos el desarrollo de ciertas actividades pedagogicas utilizadas en clases de matematicas de funcionamiento "investigativo".Zunächst unterscheiden wir die traditionelle Méthode der Mathematik, die fiir die Klassen typisch ist, die sich auf die Verwendung von Fachbiichern stiitzen, und die "investigative" Méthode, die von den Klassen angewandt wird, deren Vorgehen mit der konstruktivistischen Ausrichtung zu vereinbaren ist. Dann gehen wir auf dièse "investigative" Méthode ein und analysieren die theoretischen und tatsâchlichen Spannungen, die sie beziiglich des zugrundeliegenden Begriffs des Erlernens der Mathematik hervorruft, nàmlich dass es sich zugleich um einen aktiven Vorgang individuellen Konstruierens und um einen kulturell beeinflussten Prozess handle. Besondere Beachtung wird der Art und Weise geschenkt, mit der Konstruktivismus und die soziokulturellen Théo rien an diesen Aspekt herangehen. Schliesslich behandeln wir die Entwicklung gewisser pädagogischer Aktivitâten, die in den Klassen mit "investigativem" Vorgehen angewandt werden

The Course of Study for Senior High School English: Recent Developments, Implementation to Date, and Considerations for Future Research

The New Course of Study 2009 for Foreign languages: English (shin gakushuu shidou youryou: gaikokugo, eigo) will be enacted at the senior high school level from April 2013. The new curriculum further advocates a communicative approach to English language teaching, yet in spite of a succession of previous reforms to the national curriculum, communicative approaches to teaching English have not been widely adopted in Japanese senior high schools. The purpose of this paper, therefore, is threefold: First, I describe and explain key developments in the new curriculum; Next, I provide a review of the most recent empirical research into the implementation of the MEXT’s curricular to date, reassessing the role of university entrance examinations and drawing attention to a range of other obstacles operating against reform; Finally, I propose a suitable theoretical framework for researching teacher beliefs and intentions regarding their implementation of the Course of Study 2009

Behavior-dependent selectivity of yellowtail flounder (Limanda ferruginea) in the mouth of a commercial bottom trawl

-To improve the efficiency of a commercial bottom trawl for catching yellowtail flounder (Limanda ferruginea), we studied the behavior of individuals in the middle of the trawl mouth. Observations were conducted with a high-definition camera attached at the center of the headline of a trawl, during the brightest time of day in June 2010 off eastern Newfoundland. Behavioral responses were quantified and analyzed to evaluate predictions related to fish behavior, orientation, and capture. Individuals showed 3 different initial responses independent of fish size, gait, and fish density: they swam close to (75%), were herded away from (19%), or moved vertically away from (6%) the seabed. Individuals primarily swam in the direction of initial orientation. No fish were oriented against the trawling direction. Fish in the center of the trawl mouth tended to swim along the bottom in the trawling direction. Only individuals that were stimulated to leave the bottom were caught. Individuals in peripheral locations within the trawl mouth more often swam inward and upward. Fish that swam inward were twice as likely to be caught. Fish size, gait, and fish density did not influence the probability of capture. A trawl that stimulates yellowtail flounder to orient inward and leave the bottom would increase the efficiency of a trawl

What is required to measure the wear of explanted metal on metal hips?

Abstract INTRODUCTION There is increasing worldwide interest in the assessment of wear in explanted hip components. This is due is part to high profile failures of orthopaedic components in the US, whilst in the UK hip resurfacings have been experiencing a higher than expected failure rate. The reasons for these failures are not well understood, with data from the NJR suggesting the 43% of MoM resurfacing failures are unexplained. Wear analysis is a vital tool in determining failure mechanisms and ultimately improving the longevity of joint replacements through improved design and manufacturing control. There are currently no relevant measurement standards for the evaluation of retrieved orthopaedic components. This paper will assess two of the most commonly used techniques namely roundness measurement and co-ordinate measurement. The advantages and disadvantages of both techniques are considered in this paper. ROUNDNESS MACHINE The Talyrond 365 is a stylus based roundness machine. The component is located on a rotating table and the stylus measures the deviation from a perfect circle as the component is slowly rotated. The Talyrond measures a single profile to an accuracy of 30 nm and up to 72,000 data points per revolution. The air spindle has a radial accuracy of <0.02 μm and the Talymin gauge a minimum resolution of 12 nm. Individual roundness profiles can be stitched together to build up 3D cylinder maps, allowing 3D pictures of sections of explanted hip components to be generated. COORDINATE MEASURING MACHINE Co-ordinate measuring machines (CMMs) have been widely used in manufacturing quality and research departments for a number of years and the CMM is recognised as a powerful and important tool capable of ascertaining geometric data from a component. The CMM used in this study was a Zeiss Prismo CMM (Carl Zeiss Ltd., Rugby, UK) with a probing error of 0.7 μm. Components are securely held in a chuck fixture arrangement and the dimensions of the component in the portion of the bearing that is unworn is ascertained through measurement. The initial measurements are used to produce a reverse engineered 3D CAD surface which represents the component ‘pre-wear’ surface. The surface of the component is then scanned and the deviation from this pre-wear surface is mapped. The maximum linear wear and wear volume are then calculated directly. DISCUSSION The main advantage of CMM and Talyrond is that they are available in most metrology and measurement rooms. The CMM is a particularly versatile machine and can be used to measure any orthopaedic components. There is a need to develop a suitable Standard for both machines detailing a protocol to measure explanted hip and quantify the wear. A study is underway to measure a set of explanted hip components to allow a detailed comparison between of measurements between the Talyrond and CMM. The result of this study will be included in the paper. CONCLUSIONS The CMM and Talyrond are both instruments suited to measuring wear of explanted hips. A full evaluation of the systems and the development of robust measurement protocol and standard would be advantageous to the orthopaedic industry

Riverine Bacterial Communities Reveal Environmental Disturbance Signatures within the Betaproteobacteria and Verrucomicrobia

Riverine bacterial communities play an essential role in the biogeochemical coupling of terrestrial and marine environments, transforming elements and organic matter in their journey from land to sea. However, precisely due to the fact that rivers receive significant terrestrial input, the distinction between resident freshwater taxa vs. land-derived microbes can often become ambiguous. Furthermore, ecosystem perturbations could introduce allochthonous microbial groups and reshape riverine bacterial communities. Using full- and partial-length 16S ribosomal RNA gene sequences, we analyzed the composition of bacterial communities in the Tar River of North Carolina from November 2010 to November 2011, during which a natural perturbation occurred: the inundation of the lower reaches of an otherwise drought-stricken river associated with Hurricane Irene, which passed over eastern North Carolina in late August 2011. This event provided the opportunity to examine the microbiological, hydrological, and geochemical impacts of a disturbance, defined here as the large freshwater influx into the Tar River, superimposed on seasonal changes or other ecosystem variability independent of the hurricane. Our findings demonstrate that downstream communities are more taxonomically diverse and temporally variable than their upstream counterparts. More importantly, pre- vs. post-disturbance taxonomic comparison of the freshwater-dominant Betaproteobacteria class and the phylum Verrucomicrobia reveal a disturbance signature of previously undetected taxa of diverse origins. We use known traits of closely-related taxa to interpret the ecological function of disturbance-associated bacteria, and hypothesize that carbon cycling was enhanced post-disturbance in the Tar River, likely due to the flux of organic carbon into the system associated with the large freshwater pulse. Our analyses demonstrate the importance of geochemical and hydrological alterations in structuring bacterial communities, and illustrate the response of temperate riverine bacteria on fine taxonomic scales to a disturbance