Effective Equations of Motion for Quantum Systems

In many situations, one can approximate the behavior of a quantum system, i.e. a wave function subject to a partial differential equation, by effective classical equations which are ordinary differential equations. A general method and geometrical picture is developed and shown to agree with effective action results, commonly derived through path integration, for perturbations around a harmonic oscillator ground state. The same methods are used to describe dynamical coherent states, which in turn provide means to compute quantum corrections to the symplectic structure of an effective system.Comment: 31 pages; v2: a new example, new reference

On Information Theory, Spectral Geometry and Quantum Gravity

We show that there exists a deep link between the two disciplines of information theory and spectral geometry. This allows us to obtain new results on a well known quantum gravity motivated natural ultraviolet cutoff which describes an upper bound on the spatial density of information. Concretely, we show that, together with an infrared cutoff, this natural ultraviolet cutoff beautifully reduces the path integral of quantum field theory on curved space to a finite number of ordinary integrations. We then show, in particular, that the subsequent removal of the infrared cutoff is safe.Comment: 4 page

Instructional Alignment of Workplace Readiness Skills in Marketing Education

This study examined high school marketing education teachers’ knowledge of workplace readiness skills and whether that knowledge had an impact on student workplace readiness skill achievement. Further, this study examined the usage of Virginia’s 13 Workplace Readiness Skills curriculum and identified the teaching methods and instructional strategies used to disseminate the skills to students. Three sets of data were used for this study: teacher workplace readiness skills data, teacher survey data, and student workplace readiness skills post-test data. Pearson’s correlation was used to determine whether teacher knowledge of workplace readiness skills had an impact on student attainment of the same. The results showed that while overall teacher scores did not show a statistical significance on overall student scores, there were four individual skill areas in which there was a relationship between teacher and student scores

Adenosine Mapping for Adenosine‐Dependent Accessory Pathway Ablation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106956/1/pace12324.pd

Reproductive traits and population dynamics of benthic invertebrates indicate episodic recruitment patterns across an Arctic polar front

Climate-induced changes in the ocean and sea ice environment of the Arctic are beginning to generate major and rapid changes in Arctic ecosystems, but the effects of directional forcing on the persistence and distribution of species remain poorly understood. Here, we examine the reproductive traits and population dynamics of the bivalve Astarte crenata and sea star Ctenodiscus crispatus across a north–south transect that intersects the polar front in the Barents Sea. Both species present large oocytes indicative of short pelagic or direct development that do not differ in size–frequency between 74.5 and 81.3º latitude. However, despite gametogenic maturity, we found low frequencies of certain size classes within populations that may indicate periodic recruitment failure. We suggest that recruitment of A. crenata could occur periodically when conditions are favorable, while populations of C. crispatus are characterized by episodic recruitment failures. Pyloric caeca indices in C. crispatus show that food uptake is greatest at, and north of, the polar front, providing credence to the view that interannual variations in the quantity and quality of primary production and its flux to the seafloor, linked to the variable extent and thickness of sea ice, are likely to be strong determinants of physiological fitness. Our findings provide evidence that the distribution and long-term survival of species is not only a simple function of adaptive capacity to specific environmental changes, but will also be contingent on the frequency and occurrence of years where environmental conditions support reproduction and settlement

Invariant Gametogenic Response of Dominant Infaunal Bivalves From the Arctic Under Ambient and Near-Future Climate Change Conditions

Arctic marine ecosystems are undergoing a series of major rapid adjustments to the regional amplification of climate change, but there is a paucity of knowledge about how changing environmental conditions might affect reproductive cycles of seafloor organisms. Shifts in species reproductive ecology may influence their entire life-cycle, and, ultimately, determine the persistence and distribution of taxa. Here, we investigate whether the combined effects of warming and ocean acidification based on near-future climate change projections affects the reproductive processes in benthic bivalves (Astarte crenata and Bathyarca glacialis) from the Barents Sea. Both species present large oocytes indicative of lecithotrophic or direct larval development after ∼4 months exposure to ambient [&lt;2°C, ∼400 ppm (CO2)] and near-future [3–5°C, ∼550 ppm (CO2)] conditions, but we find no evidence that the combined effects of acidification and warming affect the size frequency distribution of oocytes. Whilst our observations are indicative of resilience of this reproductive stage to global changes, we also highlight that the successful progression of gametogenesis under standard laboratory conditions does not necessarily mean that successful development and recruitment will occur in the natural environment. This is because the metabolic costs of changing environmental conditions are likely to be offset by, as is common practice in laboratory experiments, feeding ad libitum. We discuss our findings in the context of changing food availability in the Arctic and conclude that, if we are to establish the vulnerability of species and ecosystems, there is a need for holistic approaches that incorporate multiple system responses to change.</p

Anodic Dissolution Of Zinc In Potassium Nitrate

The apparent valence of pure zinc dissolving anodically in 3% KNO3 was determined as a function of current density, temperature, and ultrasonic agitation. The apparent valence of zinc dissolving anodically at 24°C diminishes from 2.01 ± 0.01 at low current densities to 1.86 at about 50 ma and remains fairly constant up to about 80 ma cm−2. This valence is affected to some extent by the preparation, e.g., polishing of the electrode, but is independent of its structure (mono- or polycrystal). Ultrasonic vibrations do not influence the apparent valence at high current densities. In all cases a black film (corrosion product) spalls off the anode but to a larger extent with ultrasonics. The apparent valence decreases with increasing temperature (measurements between 25° and 68°C) and again with increasing current density, and appears to vary as a function of metal history. Fine metallic Zn particles are found in the dark corrosion product. The average size of the particles increases with increasing temperature. On the basis of the above, it is concluded that the normal valency of zinc ions, +2, does not change during anodic dissolution in nitrate solutions, but the apparent valence of less than 2 arises as a consequence of increased local corrosion and of surface disintegration of the anode. Both occur outside the electrical circuit thus accounting for the lower coulombic equivalent. A mechanism for the disintegration phenomenon is presented. © 1967, The Electrochemical Society, Inc. All rights reserved