Feshbach Resonance and Growth of a Bose-Einstein Condensate

Gross-Pitaevskii equation with gain is used to model Bose Einstein condensation (BEC) fed by the surrounding thermal cloud. It is shown that the number of atoms continuously injected into BEC from the reservoir can be controlled by applying the external magnetic field via Feshbach resonance.Comment: 4 page

More Network Conscious than Ever? Challenges, strategies and analytic labor of users in the Facebook Environment

Cataloged from PDF version of article.As is widely observed, social network sites (SNS) constitute a new environment of interaction where users encounter various challenges that they usually do not encounter in other environments. This study aims to provide an in-depth understanding of how users deal with the challenges in this unique environment, paying particular attention to the ways in which they examine and reflect on their social ties and networks. On the basis of 36 semistructured interviews with Facebook users, the article presents the hypothesis that participants of SNS develop a tendency to become highly observant and inquisitive about their networks and are frequently involved in an activity that the authors call analytic labor. © 2013 International Communication Association

Exploring the associations between narcissism, intentions towards infidelity, and relationship satisfaction:Attachment styles as a moderator

The ultimate goal of this research was twofold: (1) to investigate the associations between narcissism, intentions towards infidelity, and relationship satisfaction; and (2) to explore the moderating effect of attachment styles on the link between intentions towards infidelity and narcissism. The findings revealed that the link between narcissism and relationship satisfaction is fully mediated by intentions towards infidelity. Similarly, the full mediating effect of relationship satisfaction exists in the association between narcissism and intentions towards infidelity. Mediational analyses further revealed that narcissism is a predictor of intentions towards infidelity, and this link is moderated by preoccupied, fearful, and dismissive attachment styles. As the results indicate, narcissism plays a significant role in young adults’ intimate relationships, and attachment styles have a moderating role in narcissism’s effect on romantic relationships. Results and implications are discussed in light of the relevant research findings

First Results from Pan-STARRS1: Faint, High Proper Motion White Dwarfs in the Medium-Deep Fields

The Pan-STARRS1 survey has obtained multi-epoch imaging in five bands (Pan-STARRS1 gps, rps, ips, zps, and yps) on twelve "Medium Deep Fields", each of which spans a 3.3 degree circle. For the period between Apr 2009 and Apr 2011 these fields were observed 50-200 times. Using a reduced proper motion diagram, we have extracted a list of 47 white dwarf (WD) candidates whose Pan-STARRS1 astrometry indicates a non-zero proper motion at the 6-sigma level, with a typical 1-sigma proper motion uncertainty of 10 mas/yr. We also used astrometry from SDSS (when available) and USNO-B to assess our proper motion fits. None of the WD candidates exhibits evidence of statistically significant parallaxes, with a typical 1-sigma uncertainty of 8 mas. Twelve of these candidates are known WDs, including the high proper motion (1.7"/yr) WD LHS 291. We confirm three more objects as WDs through optical spectroscopy. Based on the Pan-STARRS1 colors, ten of the stars are likely to be cool WDs with 4170 K Teff 5000 K and cooling ages <9 Gyr. We classify these objects as likely thick disk WDs based on their kinematics. Our current sample represents only a small fraction of the Pan-STARRS1 data. With continued coverage from the Medium Deep Field Survey and the 3pi survey, Pan-STARRS1 should find many more high proper motion WDs that are part of the old thick disk and halo.Comment: 33 pages, 8 figures, submitted to Ap

Evaluation of the Benefits of Zero Velocity Update in Decentralized EKF-Based Cooperative Localization Algorithms for GNSS-Denied Multi-Robot Systems

This paper proposes the cooperative use of zero velocity update (ZU) in a decentralized extended Kalman filter (DEKF) based localization algorithm for multi-robot systems. The filter utilizes inertial measurement unit (IMU), ultra-wideband (UWB), and odometry velocity measurements to improve the localization performance of the system in the presence of a GNSS-denied environment. The contribution of this work is to evaluate the benefits of using ZU in a DEKF-based localization algorithm. The algorithm is tested with real hardware in a video motion capture facility and a Robot Operating System (ROS) based simulation environment for unmanned ground vehicles (UGV). Both simulation and real-world experiments are performed to show the effectiveness of using ZU in one robot to reinstate the localization of other robots in a multi-robot system. Experimental results from GNSS-denied simulation and real-world environments show that using ZU with simple heuristics in the DEKF significantly improves the 3D localization accuracy.Comment: 18 pages, preprint version, the manuscript is accepted for publication in NAVIGATION, the Journal of the Institute of Navigation. Submitted:10-11-2022, Revised: 21-04-2023, Accepted:23-06-202

A New Ultracool White Dwarf Discovered in the SuperCOSMOS Sky Survey

We present photographic B, R and I photometry, and optical and near-infrared spectroscopy, of a new ultracool white dwarf (UCWD) discovered in the SuperCOSMOS Sky Survey. The spectrum of SSSJ1556-0806 shows strong flux suppression due to the presence of collisionally induced absorption by molecular hydrogen (H2CIA), a feature characteristic of the cool, high density environments found in the atmospheres of ultracool white dwarfs. SSSJ1556-0806 therefore joins a list of <10 ultracool white dwarfs displaying extreme flux suppression. Synthetic model fitting suggests an effective temperature <3000K, which if true would make this one of the coolest white dwarfs currently known. We also exploit the similarity between the SEDs of SSSJ1556-0806 and the well-studied UCWD LHS 3250 to aid in the determination of the atmospheric parameters in a regime where models consistently fail to reproduce observations. SSSJ1556-0806 is relatively bright (R ~ 17.8), making it particularly amenable to follow up observations to obtain trigonometric parallax and IR photometry.Comment: Accepted for publication in MNRA

Milk Lactose Hydrolysis In A Batch Reactor: Optimisation Of Process Parameters, Kinetics Of Hydrolysis And Enzyme Inactivation

The present investigation describes the effects of the process quantities on enzymatic hydrolysis of milk lactose and enzyme stability. The lactose hydrolysis reactions were carried out in 250 mL of milk by using a commercial β-galactosidase produced from Kluyveromyces marxianus lactis. The residual lactose mass concentration (g L-1) and residual enzyme activity (%) against time were investigated vs. process variables such as temperature, impeller speed and enzyme concentration. Optimum conditions for hydrolysis were obtained as 37 °C, 300 rpm, 1 mL L-1 enzyme concentration and 30 min of processing time. The lactose hydrolysis process resulted in 84 % of hydrolysis degree and 52 % of residual enzyme activity at the optimum experimental conditions obtained. After evaluation of the data, it was found that the kinetics of hydrolysis and enzyme inactivation could be represented by a first order kinetic model and a single-step non-first-order enzyme inactivation kinetic model for all process conditions applied. Also, to illustrate the effect of process variables on hydrolysis and enzyme stability, some modelling studies were performed. The activation energy for hydrolysis reaction (EA) was calculated as 50.685 kJ mol-1