The Feasibility of a Fully Miniaturized Magneto-Optical Trap for Portable Ultracold Quantum Technology

Experiments using laser cooled atoms and ions show real promise for practical applications in quantum- enhanced metrology, timing, navigation, and sensing as well as exotic roles in quantum computing, networking and simulation. The heart of many of these experiments has been translated to microfabricated platforms known as atom chips whose construction readily lend themselves to integration with larger systems and future mass production. To truly make the jump from laboratory demonstrations to practical, rugged devices, the complex surrounding infrastructure (including vacuum systems, optics, and lasers) also needs to be miniatur- ized and integrated. In this paper we explore the feasibility of applying this approach to the Magneto-Optical Trap; incorporating the vacuum system, atom source and optical geometry into a permanently sealed micro- litre system capable of maintaining $10^{-10}$ mbar for more than 1000 days of operation with passive pumping alone. We demonstrate such an engineering challenge is achievable using recent advances in semiconductor microfabrication techniques and materialsComment: 23 pages, 10 figure

Digital Systems Teaching and Research (DSTR) Robot: A Flexible Platform for Education and Applied Research

The DSTR (pronounced “Disaster”) robot has a strong history of being adaptable to different user’s needs, and there are many opportunities ahead that indicate that the sky, quite literally, is not the limit for this robust platform. This paper provides a historical perspective on the development of the DSTR robot as a collaborative design developed by the Mobile Integrated Solutions Laboratory (MISL) at Texas A&M University and ASEP 4X4 Inc. Texas Instruments has been a major partner in the integration of the control electronics, and Texas Space Technology Applications and Research (T STAR) LLC has played a significant role in the propagation of the DSTR robot as an adaptable applied research/education/STEM outreach platform. The paper will present examples of the strong industry-academic relationships that allow the DSTR robot to be utilized in a multitude of experiential learning environments. In addition to a number of STEM outreach activities, the DSTR robots are being used in the Introduction to Engineering course at Blinn College and in the Freshman Engineering curriculum at Texas A&M University. DSTRs have also been selected by NASA scientists as a low-cost lunar sample collector. The paper will also discuss the newly developed DSTR-E (DSTR Engineering) unit which requires students to perform several engineering tasks during the build process. The paper will also include the lessons learned from initial design through its transfer to the private sector for commercialization and future plans.Cockrell School of Engineerin

The Relationship Between Reproduction and Mortality in Triploid Crassostrea Virginica

Unusual mortalities of cultured Crassostrea virginica in late spring have been reported from farms in the Chesapeake Bay from 2014 to 2017. None of the usual causes (e.g. disease, poor husbandry) were likely responsible, and mortalities occurred without clear signs of biological or physical stressors. Mortalities in the spring of 2014 were particularly high on over a dozen farms in Virginia, most of which were on the bayside of the Eastern Shore. Estimated losses were over 50%; however, mortalities only occurred within a four-week period between mid-May and early June. Farmers that had unusually high mortality in their crop were exclusively growing triploid oysters, which implicated triploidy as an important factor and even led to calling these events triploid mortality. Many affected farmers were also growing a northern cross, oysters made by crossing brood stock from New England to brood stock from Virginia, and relatively high fecundity was found in some triploid oysters sampled from these farms. It was hypothesized that the genetic contribution from the New England parent of the northern cross was causing aberrant gametogenesis in triploid oysters during the late spring, and that this caused triploid mortality. A controlled field test was conducted to evaluate this hypothesis and to further examine the role of genetics and gametogenesis in triploid mortality. to investigate the effect that ploidy and brood stock origin have on susceptibility to triploid mortality, four triploid and four diploid types of oysters, produced by crossing different combinations of brood stock of Virginia, Louisiana, and Maine origin, were deployed to three commercial oyster farms that experienced unusually high mortality in 2014, as well as to a control site lacking reports of unusual spring mortality. The survival and growth of oysters from each group were measured throughout the spring and summer of 2016. A mortality event (\u3e20% mortality) was observed in late spring at one site. The mortality event was only associated with triploid groups, with cumulative mortality ranging from 12 to 24% among groups. Mortality in the northern cross was not especially high (23%). The effect that gametogenesis had on the mortalities was investigated by examining histological cross sections of triploid and diploid oysters from the site where triploid mortality occurred, as well as from the control site where there was no triploid mortality. Diploid oysters at the affected site became gravid and spawned earlier than diploid oysters at the control site. Gonad development in triploid oysters was abnormal and variable, so categories were developed for classifying gonad development in triploid oysters and making comparisons between sites. No obvious difference was observed in gonad development between triploid oysters at the two sites. Cross-sections from male triploids did not typically contain any spermatozoa, and cross sections from females usually contained only a few oocytes. Gonad development may not be strongly associated with triploid mortality, but the physiology associated with abnormal gametogenesis in triploid oysters could be a major contributing factor. More work is needed on the physiological consequences of gametogenesis in triploid oysters to explain triploid mortality

Symmetric Criticality for Tight Knots

We prove a version of symmetric criticality for ropelength-critical knots. Our theorem implies that a knot or link with a symmetric representative has a ropelength-critical configuration with the same symmetry. We use this to construct new examples of ropelength critical configurations for knots and links which are different from the ropelength minima for these knot and link types.Comment: This version adds references, and most importantly an acknowledgements section which should have been in the original postin

Gauging tensor networks with belief propagation

Effectively compressing and optimizing tensor networks requires reliable methods for fixing the latent degrees of freedom of the tensors, known as the gauge. Here we introduce a new algorithm for gauging tensor networks using belief propagation, a method that was originally formulated for performing statistical inference on graphical models and has recently found applications in tensor network algorithms. We show that this method is closely related to known tensor network gauging methods. It has the practical advantage, however, that existing belief propagation implementations can be repurposed for tensor network gauging, and that belief propagation is a very simple algorithm based on just tensor contractions so it can be easier to implement, optimize, and generalize. We present numerical evidence and scaling arguments that this algorithm is faster than existing gauging algorithms, demonstrating its usage on structured, unstructured, and infinite tensor networks. Additionally, we apply this method to improve the accuracy of the widely used simple update gate evolution algorithm.Comment: 47 Pages. 11 Figure

Factors that Contribute to Resident Teaching Effectiveness

Background One of the key components of residency training is to become an educator. Resident physicians teach students, advanced practice providers, nurses, and even faculty on a daily basis. Objective The goal of this study was to identify the objective characteristics of residents, which correlate with perceived overall teaching effectiveness. Methods We conducted a one-year, retrospective study to identify factors that were associated with higher resident teaching evaluations. Senior emergency medicine (EM) teaching residents are evaluated by medical students following clinical teaching shifts. Eighteen factors pertaining to resident teaching effectiveness were chosen. Two items from the medical students' evaluations were analyzed against each factor: teaching effectiveness was measured on a five-point Likert scale and an overall teaching score (1-75). Results A total of 46 EM residents and 843 medical student evaluations were analyzed. The ACGME milestones for systems-based practice (p = 0.02) and accountability (p = 0.05) showed a statistically significant association with a rating of "five" on the Likert scale for teaching effectiveness. Three other ACGME milestones, systems-based practice (p = 0.01), task switching (p = 0.04), and team management (p = 0.03) also showed a statically significant association of receiving a score of 70 or greater on the overall teaching score. Conclusion Residents with higher performance associated with system management and accountability were perceived as highly effective teachers. USMLE and in-service exams were not predictive of higher teaching evaluations. Our data also suggest that effective teachers are working in both academic and community settings, providing a potential resource to academic departments and institutions

The Impact of Black Hole Scaling Relation Assumptions on the Mass Density of Black Holes

We examine the effect of supermassive black hole (SMBH) mass scaling relation choice on the inferred SMBH mass population since redshift $z \sim 3$. To make robust predictions for the gravitational wave background (GWB) we must have a solid understanding of the underlying SMBH demographics. Using the SDSS and 3D HST+CANDELS surveys for $0 < z < 3$ we evaluate the inferred SMBH masses from two SMBH-galaxy scaling relations: $\mathrm{M_{BH}}$-$\mathrm{M_{bulge}}$ and $\mathrm{M_{BH}}$-$\sigma$. Our SMBH mass functions come directly from stellar mass measurements for $\mathrm{M_{BH}}$-$\mathrm{M_{bulge}}$, and indirectly from stellar mass and galaxy radius measurements along with the galaxy mass fundamental plane for $\mathrm{M_{BH}}$-$\sigma$. We find that there is a substantial difference in predictions especially for $z > 1$, and this difference increases out to $z = 3$. In particular we find that using velocity dispersion predicts a greater number of SMBHs with masses greater than $10^9 \mathrm{M}_\odot$. The GWB that pulsar timing arrays find evidence for is higher in amplitude than expected from GWB predictions which rely on high redshift extrapolations of local SMBH mass-galaxy scaling relations. The difference in SMBH demographics resulting from different scaling relations may be the origin for the mismatch between the signal amplitude and predictions. Generally, our results suggest that a deeper understanding of the potential redshift evolution of these relations is needed if we are to draw significant insight from their predictions at $z > 1$Comment: Accepted by MNRA