Few-Boson Processes in the Presence of an Attractive Impurity under One-Dimensional Confinement

We consider a few-boson system confined to one dimension with a single distinguishable particle of lesser mass. All particle interactions are modeled with $\delta$-functions, but due to the mass imbalance the problem is nonintegrable. Universal few-body binding energies, atom-dimer and atom-trimer scattering lengths are all calculated in terms of two parameters, namely the mass ratio: $m_{\text{L}}/m_{\text{H}}$, and ratio $g_{\text{HH}}/g_{\text{HL}}$ of the $\delta$-function couplings. We specifically identify the values of these ratios for which the atom-dimer or atom-trimer scattering lengths vanish or diverge. We identify regions in this parameter space in which various few-body inelastic process become energetically allowed. In the Tonks-Girardeau limit ($g_{\text{HH}}\rightarrow \infty$), our results are relevant to experiments involving trapped fermions with an impurity atom

Phase Diagrams for Three-Body and Four-Body Systems in One Dimension

The phase diagrams for three-body and four-body systems with δ-function interactions are presented. The three-body and four body systems considered are the heavy-heavy-light (HHL) and heavy-heavy-heavy-light (HHHL) systems, respectively. The heavy particles are assumed to be identical. Both systems are treated within the Born-Oppenheimer approximation. The results from [16] are extended to arbitrary values of the heavy-heavy (HH) coupling. The phase diagram presented in [8] is reproduced, and the corresponding HHHL phase-diagram is presented. It was found that in both the three and four body systems the scattering lengths (atom-dimer for HHL and atom-trimer for HHHL) and spectra vary smoothly as the heavy-heavy interaction strength λ is varied from 0 to ∞

Demonstration of superluminal effects in an absorptionless, non-reflective system

We present an experimental and theoretical study of a simple, passive system consisting of a birefringent, two-dimensional photonic crystal and a polarizer in series, and show that superluminal dispersive effects can arise even though no incident radiation is absorbed or reflected. We demonstrate that a vector formulation of the Kramers-Kronig dispersion relations facilitates an understanding of these counter-intuitive effects.Comment: 6 pages, 3 figures, accepted on Physical Review Letter

Evaluation of the theoretical and in-use performance of Exhaust Air Heat Pumps

Integrated units that combine Exhaust Air Heat Pumps (EAHPs) with Heat Recovery Ventilation (HRV) and, in some instances, Domestic Hot Water Storage (DHW), are becoming increasingly popular in the domestic market across Europe with over 24,000 EAHPs purchased in the EU in 2017 alone. Early research into using EAHPs demonstrated energy savings being conservatively between 20% and 50% when compared to conventional systems. Recent research has suggested that, in reality, EAHPs in-use energy performance can be worse than that estimated by various standardised theoretical assessment methods (COP/SPF in the range of 0.4 to 6.0). More worryingly, published data on this in-use operation is effectively non-existent for NZEB type dwellings and few studies have stress tested the robustness of the EN standards in accounting for the effects of in-use operation. The study presented in this paper investigated whether the standard methods used to predict in-use energy performance are sufficiently robust and adequately capture operational performance for EAHP systems. The energy performance of two identical EAHP systems in Ireland (one rural/ one urban) were monitored for close to 12 months. During the live in-use monitoring period, the EAHPs had ‘heat-pump/heat recovery only’ operating mode ratios of 16%/84% and 22%/77% for rural and urban systems respectively. The average HRE in-use efficiency was 92% and 64% for the rural and urban systems respectively. While the manufacturers stated Seasonal performance factors (SPF) ranging from 2.2 (for DHW) to 5.8 (for Space Heating), the average in-use SPF was found to vary between 1.7 and 3.8 depending on the boundary reported and the location. More research is urgently required in order to bring much needed clarity for designers and energy assessors regarding which boundaries can be universally applied to EAHP systems. Given the range of SPF which could apply to the HP’s examined, the paper highlights the importance of ensuring that realistic indicators of in use performance are provided, aiding appropriate decision-making by policymakers, industry and end-users

Thyroid Lymphoma as a Cause of Dysphagia and Dyspnea in a Patient without Palpable Nodules or Goiter

Tumors originating in the neck are well-known causes of progressive dysphagia and dyspnea (including stridor), and thyroid lymphoma is an uncommon example. Physical examination provides an important first step in the evaluation of such complaints, as tumors large enough to produce such symptoms are typically considered to be palpable, if not able to be seen grossly. In this case presentation, the authors describe a nonsubsternal thyroid lymphoma measuring 3 × 4 cm at its largest diameter, producing dysphagia and leading to respiratory emergency, that was entirely nonpalpable to physical exam even after confirmation of its presence by computed tomography

Constraining the False Positive Rate for Kepler Planet Candidates with Multi-Color Photometry from the GTC

Using the OSIRIS instrument installed on the 10.4-m Gran Telescopio Canarias (GTC) we acquired multi-color transit photometry of four small (Rp < 5 R_Earth) short-period (P < 6 days) planet candidates recently identified by the Kepler space mission. These observations are part of a program to constrain the false positive rate for small, short-period Kepler planet candidates. Since planetary transits should be largely achromatic when observed at different wavelengths (excluding the small color changes due to stellar limb darkening), we use the observed transit color to identify candidates as either false positives (e.g., a blend with a stellar eclipsing binary either in the background/foreground or bound to the target star) or validated planets. Our results include the identification of KOI 225.01 and KOI 1187.01 as false positives and the tentative validation of KOI 420.01 and KOI 526.01 as planets. The probability of identifying two false positives out of a sample of four targets is less than 1%, assuming an overall false positive rate for Kepler planet candidates of 10% (as estimated by Morton & Johnson 2011). Therefore, these results suggest a higher false positive rate for the small, short-period Kepler planet candidates than has been theoretically predicted by other studies which consider the Kepler planet candidate sample as a whole. Furthermore, our results are consistent with a recent Doppler study of short-period giant Kepler planet candidates (Santerne et al. 2012). We also investigate how the false positive rate for our sample varies with different planetary and stellar properties. Our results suggest that the false positive rate varies significantly with orbital period and is largest at the shortest orbital periods (P < 3 days), where there is a corresponding rise in the number of detached eclipsing binary stars... (truncated)Comment: 13 pages, 12 figures, 3 tables; revised for MNRA

Athletic Ticket Pricing in the Collegiate Environment: An Agenda for Research

s pressure mounts for intercollegiate athletic departments to be more selfsufficient, administrators must respond by increasing generated revenues. Despite the importance of ticket sales in this endeavor, however, little is known about the underlying ticket pricing structures and policies used by National Collegiate Athletic Association (NCAA) institutions. Of the limited existing scholarship focused on managerial pricing decisions in the field of sport management, only professional sports settings have been addressed. Given the unique operational differences between professional and intercollegiate sport, this paper is designed to establish a foundation from which to build future research concerning the pricing of college sport tickets. The frameworks of stakeholder theory and institutional theory are proposed to ground future study in an attempt to strengthen our understanding of the process and behavior of price setting in intercollegiate athletics

Athletic Ticket Pricing in the Collegiate Environment: An Agenda for Research

As pressure mounts for intercollegiate athletic departments to be more selfsufficient, administrators must respond by increasing generated revenues. Despite the importance of ticket sales in this endeavor, however, little is known about the underlying ticket pricing structures and policies used by National Collegiate Athletic Association (NCAA) institutions. Of the limited existing scholarship focused on managerial pricing decisions in the field of sport management, only professional sports settings have been addressed. Given the unique operational differences between professional and intercollegiate sport, this paper is designed to establish a foundation from which to build future research concerning the pricing of college sport tickets. The frameworks of stakeholder theory and institutional theory are proposed to ground future study in an attempt to strengthen our understanding of the process and behavior of price setting in intercollegiate athletics

Seston quality drives feeding, stoichiometry and excretion of zebra mussels

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136507/1/fwb12892.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136507/2/fwb12892_am.pd