Perturbation Theory for Plasmonic Modulation and Sensing

We develop a general perturbation theory to treat small parameter changes in dispersive plasmonic nanostructures and metamaterials. We specifically apply it to dielectric refractive index, and metallic plasma frequency modulation in metal- dielectric nanostructures. As a numerical demonstration, we verify the theory's accu- racy against direct calculations, for a system of plasmonic rods in air where the metal is defined by a two-pole fit of silver's dielectric function. We also discuss new optical behavior related to plasma frequency modulation in such systems. Our approach provides new physical insight for the design of plasmonic devices for biochemical sensing and optical modulation, and future active metamaterial applications.Comment: 17 pages, 6 figure

An Optically Plugged Quadrupole Trap for Bose-Einstein Condensates

We created sodium Bose-Einstein condensates in an optically plugged quadrupole magnetic trap (OPT). A focused, 532nm laser beam repelled atoms from the coil center where Majorana loss is significant. We produced condensates of up to $3 \times 10^7$ atoms, a factor of 60 improvement over previous work [1], a number comparable to the best all-magnetic traps, and transferred up to $9 \times 10^6$ atoms into a purely optical trap. Due to the tight axial confinement and azimuthal symmetry of the quadrupole coils, the OPT shows promise for creating Bose-Einstein condensates in a ring geometry

Quantum and Classical Dynamics of a BEC in a Large-Period Optical Lattice

We experimentally investigate diffraction of a Rb-87 Bose-Einstein condensate from a 1D optical lattice. We use a range of lattice periods and timescales, including those beyond the Raman-Nath limit. We compare the results to quantum mechanical and classical simulations, with quantitative and qualitative agreement, respectively. The classical simulation predicts that the envelope of the time-evolving diffraction pattern is shaped by caustics: singularities in the phase space density of classical trajectories. This behavior becomes increasingly clear as the lattice period grows.Comment: 7 pages, 6 figure

Psychological outcomes following surgical and endoscopic bariatric procedures: A systematic review.

Obesity is a leading global epidemic. Bariatric surgery is the only treatment demonstrating substantial long-term weight loss and medical benefits. However, there is limited research on the psychological outcomes following surgery. Therefore, the primary aim of this study was to systematically review depression, anxiety, and binge eating outcomes at different time points following bariatric surgery and identify whether bariatric surgery significantly reduces psychological symptoms over time. These outcomes were also examined among endoscopic bariatric procedures as a secondary aim. Forty-eight studies met inclusion criteria. Findings suggested that most patients experience a short-term reduction in anxiety and depression symptoms from pre-surgery. Over time, however, these symptoms increase and may even return to pre-surgery levels. Furthermore, while binge eating was uncommon after surgery, other disordered eating patterns may emerge. Binge eating may also restart over time as the stomach enlarges again. Overall, the complex psychological difficulties faced by individuals with obesity continue after surgery and may contribute to longer-term weight recidivism. More comprehensive and standardised psychological assessment procedures, including clinical interviews and longer-term follow-up, may provide insight into the psychological mechanisms maintaining weight management issues, and may serve as a starting point for improving the long-term success of patients with obesity

Bragg Spectroscopy of Vortex Lattices in Bose-Einstein condensates

We have measured the velocity field of a vortex lattice within a sodium Bose-Einstein condensate using Bragg scattering. The phase gradient of the macroscopic wavefunction was mapped into the spatial structure of the diffracted atom cloud, allowing for single shot measurement of the rotation parameters. A combination of spectral and spatial information yields a complete description of the superfluid flow, coarse-grained over the lattice structure, including direct and independent measurements of the rate and sense of rotation. Signatures of the microscopic quantum rotation have also been observed.Comment: 5 pages, 5 Figures, A movie built from the CM data is available in our Webpage: http://www.physics.gatech.edu/chandra/index.htm; added Fig.5 presents new data, showing signatures of the microscopic vortex structure in the diffracted clou

The clinical obesity maintenance model: a structural equation model.

PURPOSE:Theoretical research on the psychological underpinnings of weight management is limited. Recently, the clinical obesity maintenance model (COMM) proposed a theoretical conceptualisation of salient psychological and neuropsychological mechanisms maintaining weight management issues. The current study aimed to empirically test the COMM and elucidate the results in the context of recent empirical findings. METHODS:Participants (N = 165) were recruited from university and community settings in Australia. The sample consisted of adults with normal weight (n = 41), overweight (n = 40), and obesity (n = 84). Participants completed self-report questionnaires and a brief neuropsychological test. Structural equation modelling was used to estimate the associations between the hypothesised variables of the COMM and evaluate the model fit. RESULTS:Findings suggested acceptable to good model fit. Furthermore, several direct effects were found. First, cognitive flexibility directly affected eating habit strength. Second, eating habit strength directly affected eating beliefs. Third, eating beliefs directly affected emotion dysregulation. Fourth, emotion dysregulation directly affected depression and binge eating with depression partially mediating this relationship. Finally, depression directly affected binge eating. CONCLUSION:This was the first study to empirically test the COMM. Overall, findings provide preliminary support for the COMM as a psychological model of weight management and highlight the underlying psychological and neuropsychological mechanisms that may contribute to weight management issues. As this study examined a simplified version of the COMM, future research should continue evaluating this model and consider incorporating these components into more holistic weight management models to improve long-term treatment outcomes. LEVEL OF EVIDENCE:V, cross-sectional descriptive study

Subset feedback vertex set is fixed parameter tractable

The classical Feedback Vertex Set problem asks, for a given undirected graph G and an integer k, to find a set of at most k vertices that hits all the cycles in the graph G. Feedback Vertex Set has attracted a large amount of research in the parameterized setting, and subsequent kernelization and fixed-parameter algorithms have been a rich source of ideas in the field. In this paper we consider a more general and difficult version of the problem, named Subset Feedback Vertex Set (SUBSET-FVS in short) where an instance comes additionally with a set S ? V of vertices, and we ask for a set of at most k vertices that hits all simple cycles passing through S. Because of its applications in circuit testing and genetic linkage analysis SUBSET-FVS was studied from the approximation algorithms perspective by Even et al. [SICOMP'00, SIDMA'00]. The question whether the SUBSET-FVS problem is fixed-parameter tractable was posed independently by Kawarabayashi and Saurabh in 2009. We answer this question affirmatively. We begin by showing that this problem is fixed-parameter tractable when parametrized by |S|. Next we present an algorithm which reduces the given instance to 2^k n^O(1) instances with the size of S bounded by O(k^3), using kernelization techniques such as the 2-Expansion Lemma, Menger's theorem and Gallai's theorem. These two facts allow us to give a 2^O(k log k) n^O(1) time algorithm solving the Subset Feedback Vertex Set problem, proving that it is indeed fixed-parameter tractable.Comment: full version of a paper presented at ICALP'1

The Clinical Obesity Maintenance Model: A Theoretical Framework for Bariatric Psychology.

Ranked highly in its association with serious medical comorbidities, obesity, a rapidly growing epidemic worldwide, poses a significant socio-economic burden. While bariatric procedures offer the most efficacious treatment for weight loss, a subset of patients risk weight recidivism. Due to the heterogeneity of obesity, it is likely that there are phenotypes or sub-groups of patients that require evidence-based psychological support to produce more sustainable outcomes. So far, however, characteristics of patients have not led to a personalized treatment algorithm for bariatric surgery. Maintenance of weight loss following bariatric surgery requires long-term modification of eating behaviors and physical activity. A recent Clinical Obesity Maintenance Model (COMM) proposed a conceptual framework of salient constructs, including the role of habit, behavioral clusters, emotion dysregulation, mood, health literacy, and executive function as interconnected drivers of obesity maintaining behaviors relevant to the field of bariatric psychology. The primary aim of this concise review is to bring together emerging findings from experimental and epidemiological studies relating to the COMM constructs that may inform the assessment and follow up of bariatric surgery. We also aim to explain the phenotypes that need to be understood and screened prior to bariatric surgery to enable better pre-surgery intervention and optimum post-surgery response

RLZAP: Relative Lempel-Ziv with Adaptive Pointers

Relative Lempel-Ziv (RLZ) is a popular algorithm for compressing databases of genomes from individuals of the same species when fast random access is desired. With Kuruppu et al.'s (SPIRE 2010) original implementation, a reference genome is selected and then the other genomes are greedily parsed into phrases exactly matching substrings of the reference. Deorowicz and Grabowski (Bioinformatics, 2011) pointed out that letting each phrase end with a mismatch character usually gives better compression because many of the differences between individuals' genomes are single-nucleotide substitutions. Ferrada et al. (SPIRE 2014) then pointed out that also using relative pointers and run-length compressing them usually gives even better compression. In this paper we generalize Ferrada et al.'s idea to handle well also short insertions, deletions and multi-character substitutions. We show experimentally that our generalization achieves better compression than Ferrada et al.'s implementation with comparable random-access times