Bose-Einstein condensates with attractive 1/r interaction: The case of self-trapping

Amplifying on a proposal by O'Dell et al. for the realization of Bose-Einstein condensates of neutral atoms with attractive $1/r$ interaction, we point out that the instance of self-trapping of the condensate, without external trap potential, is physically best understood by introducing appropriate "atomic" units. This reveals a remarkable scaling property: the physics of the condensate depends only on the two parameters $N^2 a/a_u$ and $\gamma/N^2$, where $N$ is the particle number, $a$ the scattering length, $a_u$ the "Bohr" radius and $\gamma$ the trap frequency in atomic units. We calculate accurate numerical results for self-trapping wave functions and potentials, for energies, sizes and peak densities, and compare with previous variational results. As a novel feature we point out the existence of a second solution of the extended Gross-Pitaevskii equation for negative scattering lengths, with and without trapping potential, which is born together with the ground state in a tangent bifurcation. This indicates the existence of an unstable collectively excited state of the condensate for negative scattering lengths.Comment: 7 pages, 7 figures, to appear in Phys. Rev.

Spin Hall Conductance of the Two Dimensional Hole Gas in a Perpendicular Magnetic Field

The charge and spin Hall conductance of the two-dimensional hole gas within the Luttinger model with and without inversion symmetry breaking terms in a perpendicular magnetic field are studied, and two key phenomena are predicted. The sign of the spin Hall conductance is modulated periodically by the external magnetic field, which means a possible application in the future. Furthermore, a resonant spin Hall conductance in the two-dimensional hole gas with a certain hole density at a typical magnetic field is indicated, which implies a likely way to firmly establish the intrinsic spin Hall effect. The charge Hall conductance is unaffected by the spin-orbit coupling.Comment: accepted for publication in Phys. Rev. B; 6 pages, 4 figure

Applications of Sequential Learning for Medical Image Classification

Purpose: The aim of this work is to develop a neural network training framework for continual training of small amounts of medical imaging data and create heuristics to assess training in the absence of a hold-out validation or test set. Materials and Methods: We formulated a retrospective sequential learning approach that would train and consistently update a model on mini-batches of medical images over time. We address problems that impede sequential learning such as overfitting, catastrophic forgetting, and concept drift through PyTorch convolutional neural networks (CNN) and publicly available Medical MNIST and NIH Chest X-Ray imaging datasets. We begin by comparing two methods for a sequentially trained CNN with and without base pre-training. We then transition to two methods of unique training and validation data recruitment to estimate full information extraction without overfitting. Lastly, we consider an example of real-life data that shows how our approach would see mainstream research implementation. Results: For the first experiment, both approaches successfully reach a ~95% accuracy threshold, although the short pre-training step enables sequential accuracy to plateau in fewer steps. The second experiment comparing two methods showed better performance with the second method which crosses the ~90% accuracy threshold much sooner. The final experiment showed a slight advantage with a pre-training step that allows the CNN to cross ~60% threshold much sooner than without pre-training. Conclusion: We have displayed sequential learning as a serviceable multi-classification technique statistically comparable to traditional CNNs that can acquire data in small increments feasible for clinically realistic scenarios

Body odor quality predicts behavioral attractiveness in humans

Growing effort is being made to understand how different attractive physical traits co-vary within individuals, partly because this might indicate an underlying index of genetic quality. In humans, attention has focused on potential markers of quality such as facial attractiveness, axillary odor quality, the second-to-fourth digit (2D:4D) ratio and body mass index (BMI). Here we extend this approach to include visually-assessed kinesic cues (nonverbal behavior linked to movement) which are statistically independent of structural physical traits. The utility of such kinesic cues in mate assessment is controversial, particularly during everyday conversational contexts, as they could be unreliable and susceptible to deception. However, we show here that the attractiveness of nonverbal behavior, in 20 male participants, is predicted by perceived quality of their axillary body odor. This finding indicates covariation between two desirable traits in different sensory modalities. Depending on two different rating contexts (either a simple attractiveness rating or a rating for long-term partners by 10 female raters not using hormonal contraception), we also found significant relationships between perceived attractiveness of nonverbal behavior and BMI, and between axillary odor ratings and 2D:4D ratio. Axillary odor pleasantness was the single attribute that consistently predicted attractiveness of nonverbal behavior. Our results demonstrate that nonverbal kinesic cues could reliably reveal mate quality, at least in males, and could corroborate and contribute to mate assessment based on other physical traits

Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs

Jellyfish blooms are common in many oceans, and anthropogenic changes appear to have increased their magnitude in some regions. Although mass falls of jellyfish carcasses have been observed recently at the deep seafloor, the dense necrophage aggregations and rapid consumption rates typical for vertebrate carrion have not been documented. This has led to a paradigm of limited energy transfer to higher trophic levels at jelly falls relative to vertebrate organic falls. We show from baited camera deployments in the Norwegian deep sea that dense aggregations of deep-sea scavengers (more than 1000 animals at peak densities) can rapidly form at jellyfish baits and consume entire jellyfish carcasses in 2.5 h. We also show that scavenging rates on jellyfish are not significantly different from fish carrion of similar mass, and reveal that scavenging communities typical for the NE Atlantic bathyal zone, including the Atlantic hagfish, galatheid crabs, decapod shrimp and lyssianasid amphipods, consume both types of carcasses. These rapid jellyfish carrion consumption rates suggest that the contribution of gelatinous material to organic fluxes may be seriously underestimated in some regions, because jelly falls may disappear much more rapidly than previously thought. Our results also demonstrate that the energy contained in gelatinous carrion can be efficiently incorporated into large numbers of deep-sea scavengers and food webs, lessening the expected impacts (e.g. smothering of the seafloor) of enhanced jellyfish production on deep-sea ecosystems and pelagic–benthic coupling

A longitudinal study of adolescents’ judgments of the attractiveness of facial symmetry, averageness and sexual dimorphism

Adolescents have been found to differ by age in their attraction to facial symmetry, averageness, and sexual dimorphism. However, it has not been demonstrated that attraction to these facial characters changes over time as a consequence of age-linked development. We aimed to extend previous cross-sectional findings by examining whether facial attractiveness judgments change over time during adolescence as a consequence of increasing age, in a within-subjects study of two cohorts of adolescents aged 11–16. Consistent with previous findings, we find that adolescents (often particularly females) judged faces with increased averageness, symmetry and femininity to be more attractive than original, asymmetric and masculine faces, respectively. However, we do not find longitudinal changes in face preference judgments across the course of a year, leading us to question the extent to which some of the previously reported differences in facial attractiveness judgments between younger and older adolescents were due to age-linked changes

Age, puberty and attractiveness judgments in adolescents

Previous work has suggested that judgments of the attractiveness of some facial and vocal features change during adolescence. Here, over 70 Czech adolescents aged 12–14 made forced-choice attractivenessjudgments on adolescent faces manipulated in symmetry, averageness and femininity, and on adolescent opposite-sex voices manipulated in fundamental frequency (perceived as pitch), and completed questionnaires on pubertal development. Consistent with typical adult judgments, adolescents selected the symmetric, average and feminine male and female faces as more attractive significantly more often than the asymmetric, non-average and masculine faces respectively. Moreover, preferences for symmetric faces were positively associated with adolescents’ age and stage of pubertal development. Unexpectedly, voice pitch did not significantly influence adolescents’ attractivenessjudgments. Collectively, these findings present new evidence using refined methodology that adolescent development is related to variation in attractivenessjudgments

Comparison of resource use by COPD patients on inhaled therapies with long-acting bronchodilators: a database study

<p>Abstract</p> <p>Background</p> <p>The purpose of this analysis was to compare health care costs and utilization among COPD patients who had long-acting beta-2 agonist (LABA) OR long-acting muscarinic antagonist (LAMA); LABA AND LAMA; or LABA, LAMA, AND inhaled corticosteroid (ICS) prescription claims.</p> <p>Methods</p> <p>This was a 12 month pre-post, retrospective analysis using COPD patients in a national administrative insurance database. Propensity score and exact matching were used to match patients 1:1:1 between the LABA or LAMA (formoterol, salmeterol, or tiotropium), LABA and LAMA (tiotropium/formoterol or tiotropium/salmeterol), and LABA, LAMA and ICS (bronchodilators plus steroid) groups. Post-period comparisons were evaluated with analysis of covariance. Costs were evaluated from a commercial payer perspective.</p> <p>Results</p> <p>A total of 523 patients were matched using 29 pre-period variables (e.g., demographics, medication exposure). Post-match assessments indicated balance among the cohorts. COPD-related costs differed among groups (LABA or LAMA $2,051 SE = 91; LABA and LAMA$2,823 SE = 62; LABA, LAMA and ICS $3,546 SE = 89; all p < .0001) with the differences driven by study medication costs. However, non-study COPD medication costs were higher for the LABA or LAMA therapy group ($911 SE = 91) compared to the LABA and LAMA therapy group ($668 SE = 58; p = 0.0238) and non-study respiratory medications were approximately$100 greater for the LABA or LAMA therapy group relative to both LABA and LAMA (p = .0018) and LABA, LAMA, and ICS (p = .0071) therapy groups. While there was no observed difference in outpatient costs, there was a slightly higher number of outpatient visits per patient in the LABA and LAMA (25.5 SE = 0.9, p = 0.0070) relative to the LABA or LAMA therapy group (22.3 SE = 0.8) and higher utilization (89.7% of patients) with COPD visits in the LABA and LAMA therapy group relative to both the LABA or LAMA (73.8%; p < .0001) and LABA, LAMA and ICS therapy groups (85.3; p = 0.0305).</p> <p>Conclusions</p> <p>Significant cost differences driven mainly by pharmaceuticals were observed among LABA or LAMA, LABA and LAMA and LABA, LAMA and ICS therapies. A COPD-related cost offset was observed from single bronchodilator to two bronchodilators. Addition of an ICS with two bronchodilators resulted in higher treatment costs without reduction in other COPD-related costs compared with two bronchodilators.</p

Creativity in public involvement: supporting authentic collaboration and inclusive research with seldom heard voices

Background The role of public involvement (PI) in healthcare research is growing in importance and it is imperative that researchers continuously reflect on how to promote the inclusion of patients and service users in the design and delivery of research. PI offers a mechanism for end-users to be involved planning, executing, and reporting research. Some patient groups, including people who have communication difficulties, may struggle to engage in the methods traditionally employed to promote PI engagement such as questionnaires and focus groups. Methods This article describes a longitudinal case-study of a PI group, consisting of people who have communication difficulties, for a patient-reported outcome development project. Creative methods, informed by the participatory design principles of enacting, seeing and doing, were introduced stepwise into seven PI meetings. Data from video and visual minutes were used to evaluate the impact of the methods, following each group. Feedback, in the form of verbal and visual outputs taken directly from group meeting minutes, along with vignettes evidenced the impact of the methods on the project and group members. Results Creative methods enabled the PI group members to successfully contribute in meetings, to interact dynamically and to engage with the aims and processes of the research project. Their involvement facilitated the development of accessible recruitment materials, informed data analysis and supported the dissemination of project outputs. Employing creative methods also enabled both PI group members and the academic team to reflect on their own roles within the research project and the impact that their active involvement in the PI group has had on their personal development and perspectives on research. Conclusion The impact of using creative methods in PI for this patient-reported outcome measure (PROM) development project improved collaboration and understanding between PI members and the academic team. The authentic engagement of people who have communication difficulties in PI generated a more accessible project in terms of both process and impact. Creativity has applicability beyond people whose communication is non-verbal; it should be harnessed by research teams to identify and breakdown barriers to involvement to develop outcome tools that reflect the diversity of our populations