Technology and manufacturing in the seventh district

Technology ; Federal Reserve District, 7th ; Manufactures - North Central states

Economic development efforts in the seventh district

Economic development - North Central states ; Federal Reserve District, 7th

Pre-participation Cardiac Screening in Young Athletes: Models and Criteria

This is the second of two review articles focusing on the value of preparticipation cardiac screening in young athletes. The article focuses on the efficacy of the resting 12-lead electrocardiogram (ECG), physical examination, and medical history questionnaire, which commonly make up the first stage of a cardiac screening protocol. The review then focuses on specific structural and electrical abnormalities which are responsible for sudden cardiac death (SCD) in young athletes – the most common of which is hypertrophic cardiomyopathy. The identification of appropriate ‘red flag’ signs and symptoms is essential for teasing out potential pathological conditions and allowing differentiation from often benign physiological adaptations. The final section provides guidance on how the resting 12-lead ECG can be used to separate pathological from physiological adaptations in young athletes

The phase sensitivity of a fully quantum three-mode nonlinear interferometer

We study a nonlinear interferometer consisting of two consecutive parametric amplifiers, where all three optical fields (pump, signal and idler) are treated quantum mechanically, allowing for pump depletion and other quantum phenomena. The interaction of all three fields in the final amplifier leads to an interference pattern from which we extract the phase uncertainty. We find that the phase uncertainty oscillates around a saturation level that decreases as the mean number $N$ of input pump photons increases. For optimal interaction strengths, we also find a phase uncertainty below the shot-noise level and obtain a Heisenberg scaling $1/N$. This is in contrast to the conventional treatment within the parametric approximation, where the Heisenberg scaling is observed as a function of the number of down-converted photons inside the interferometer.Comment: 8 pages, 7 figure

Farm fence end and corner design

Field surveys of farm fences show that many are in poor condition. The end construction is a critical factor in the successful performance of a fence. The study herein described was undertaken to find the causes for failure, to appraise the relative value of common construction methods and to attempt to devise better ones. Particular attention has be.en given to labor saving in the hope that knowledge of improved methods would result in more satisfactory construction on the farm. A field study disclosed the factors responsible for failure, gave some information on loadings to be expected and some suggestions for assemblies which might be built with a minimum of materials and labor and still be expected to give satisfactory service. The experimental work included observations of loads which might be imposed on the fence end or corner by wire fencing, and a study of forces necessary to destroy ends and corners fabricated in a variety of ways. A test was made to show the effect of time and temperature on the tension in wire fencing and the ability of two types of fence ends to resist such factors. Field tests were made in one soil type only and under approximately similar soil moisture conditions. In most cases, replications have not been possible

The effectiveness of roofing nails for application of metal building sheets

The roofing nail is an important and often a limiting factor in successfully using metal building sheets. This study has been directed toward an analysis of the problems involved and the comparative performance of typical special nails offered commercially for fastening building sheets. All nails used for fastening steel sheets exposed to the weather should have a protective coating such as galvanizing, and a head which will exclude moisture from the hole made by the nail. The tendency of nails to creep\u27 or move outward without any apparent cause, thus necessitating renailing, has been a troublesome problem. No definite conclusions have been reached regarding the causes of this phenomenon, but some suggestions are offered for its remedy. Forces exerted by the wind and by the expansion and contraction of the metal due to changes in temperature may have some influence in loosening the nail. Creeping of nails from asphalt roofing and from boxes, however, shows that internal forces are probably of major importance. These may be the minute changes in dimension and character of the wood as it absorbs or gives up moisture. Screw shank nails probably creep less than plain shank nails, and it appears that ring shank nails will not creep. Many failures have been the result of using poor nailing girts or of carelessness on the part of the workman in failing to hit the girt

Improving the mesomorphic behaviour of supramolecular liquid crystals by resonance-assisted hydrogen bonding

A systematic structure-property relationship study on hydrogen-bonded liquid crystals was performed, revealing the impact of resonance-assisted hydrogen bonds (RAHBs) on the self-assembling behavior of the supramolecular architecture. The creation of a six-membered intramolecular hydrogen-bonded ring acts as a counterpart to the self-organization between hydrogen bond donators and acceptors and determines thus the suprastructure. Variation of the hydrogen-bonding pattern allowed us to significantly improve the temperature range of the reported liquid crystalline assemblies

Cooling dynamics of a dilute gas of inelastic rods: a many particle simulation

We present results of simulations for a dilute gas of inelastically colliding particles. Collisions are modelled as a stochastic process, which on average decreases the translational energy (cooling), but allows for fluctuations in the transfer of energy to internal vibrations. We show that these fluctuations are strong enough to suppress inelastic collapse. This allows us to study large systems for long times in the truely inelastic regime. During the cooling stage we observe complex cluster dynamics, as large clusters of particles form, collide and merge or dissolve. Typical clusters are found to survive long enough to establish local equilibrium within a cluster, but not among different clusters. We extend the model to include net dissipation of energy by damping of the internal vibrations. Inelatic collapse is avoided also in this case but in contrast to the conservative system the translational energy decays according to the mean field scaling law, E(t)\propto t^{-2}, for asymptotically long times.Comment: 10 pages, 12 figures, Latex; extended discussion, accepted for publication in Phys. Rev.

Measurement of the Photon-Plasmon Coupling Phase

Scattering processes have played a crucial role in the development of quantum theory. In the field of optics, scattering phase shifts have been utilized to unveil interesting forms of light-matter interactions. Here, we investigate the mode-coupling phase of single photons to surface plasmon polaritons in a quantum plasmonic tritter. We observe that the coupling process induces a phase jump that occurs when photons scatter into surface plasmons and vice versa. This interesting coupling phase dynamics is of particular relevance for quantum plasmonic experiments. Furthermore, it is demonstrated that this photon-plasmon interaction can be modeled through a quantum-mechanical tritter. We show that the visibility of a double-slit and a triple-slit interference patterns are convenient observables to characterize the interaction at a slit and determine the coupling phase. Our accurate and simple model of the interaction, validated by simulations and experiments, has important implications not only for quantum plasmonic interference effects, but is also advantageous to classical applications