Twisted Nano-optics: Manipulating Light at the Nanoscale with Twisted Phonon Polaritonic Slabs

Recent discoveries have shown that when two layers of van der Waals (vdW) materials are superimposed with a relative twist angle between their respective in-plane principal axes, the electronic properties of the coupled system can be dramatically altered. Here, we demonstrate that a similar concept can be extended to the optics realm, particularly to propagating polaritons, hybrid light-matter interactions. To do this, we fabricate stacks composed of two twisted slabs of a polar vdW crystal (MoO3) supporting low-loss anisotropic phonon polaritons (PhPs), and image the propagation of the latter when launched by localized sources (metal antennas). Our images reveal that under a critical angle the PhPs isofrequency curve (determining the PhPs momentum at a fixed frequency) undergoes a topological transition. Remarkably, at this angle, the propagation of PhPs is strongly guided along predetermined directions (canalization regime) with no geometrical spreading (diffraction-less). These results demonstrate a new degree of freedom (twist angle) for controlling the propagation of polaritons at the nanoscale with potential for nano-imaging, (bio)-sensing, quantum applications and heat management

ALTERNATIVA PARA LA COMERCIALIZACIÓN DEL CHICOZAPOTE (achras sapota): TECNOLOGÃA DE LOS TRATAMIENTOS MÃNIMOS

Chicozapote ( ) is one of the fruit species that at the moment a great potential has, as much commercial as economic, nevertheless, it is a fruit that quickly deteriorates after the harvest taking place diverse biochemical reactions that take to the nondesirable softening, darkening and other aspects, with the consequent loss of the quality of the fruit, thus diminishing its acceptability, and reducing its life utility. A solution to these problems represents the technology of minimum treatments. The objective of this work was to evaluate the effect of diverse conservatives and the temperature on the life utility of fractions of chicozapote. For the accomplishment of this work fruits of chicozapote with a degree of acceptable maturity were used (good color, firmness, size, etc.). 50 fractions of gr. of chicozapote were put under the following treatments: 1) solution of CaCl2 to 1%; 2) a solution of CaCl2 to 2%; 3) ascórbico acid solution and acid citrus, both to 1%; and 4) with solution of ascórbico acid 1,0% and citric acid to 0,5%. All with chlorine (200 ppm). They were dried and they stored to 4, 8 and 22 °C., as variable of answer were evaluated: pH, % acidity, water activity, firmness, ºBrix, reducing sugars, acetaldehído, ethanol, microbiological and sensorial analysis. The best treatment was the 1% mixture ascórbico acid and 0,5% of citric acid with storage to 4°C; prolonging the life of useful of the product until by 36 days, conserving pleasant flavor and color within the accepted characteristics of quality, being the technology of minimum treatments a strategy for the conservation and commercialization of chicozapote.chicozapote, life utility, minimumly process, low temperatures, chicozapote, vida útil, mínimamente procesados, bajas temperaturas, Crop Production/Industries, Marketing,

The Low Redshift survey at Calar Alto (LoRCA)

The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of galaxies provides a standard ruler to measure the accelerated expansion of the Universe. To extract all available information about dark energy, it is necessary to measure a standard ruler in the local, z<0.2, universe where dark energy dominates most the energy density of the Universe. Though the volume available in the local universe is limited, it is just big enough to measure accurately the long 100 Mpc/h wave-mode of the BAO. Using cosmological N-body simulations and approximate methods based on Lagrangian perturbation theory, we construct a suite of a thousand light-cones to evaluate the precision at which one can measure the BAO standard ruler in the local universe. We find that using the most massive galaxies on the full sky (34,000 sq. deg.), i.e. a K(2MASS)<14 magnitude-limited sample, one can measure the BAO scale up to a precision of 4\% and 1.2\% using reconstruction). We also find that such a survey would help to detect the dynamics of dark energy.Therefore, we propose a 3-year long observational project, named the Low Redshift survey at Calar Alto (LoRCA), to observe spectroscopically about 200,000 galaxies in the northern sky to contribute to the construction of aforementioned galaxy sample. The suite of light-cones is made available to the public.Comment: 15 pages. Accepted in MNRAS. Please visit our website: http://lorca-survey.ft.uam.es

Electrophysiological Heterogeneity of Fast-Spiking Interneurons: Chandelier versus Basket Cells

In the prefrontal cortex, parvalbumin-positive inhibitory neurons play a prominent role in the neural circuitry that subserves working memory, and alterations in these neurons contribute to the pathophysiology of schizophrenia. Two morphologically distinct classes of parvalbumin neurons that target the perisomatic region of pyramidal neurons, chandelier cells (ChCs) and basket cells (BCs), are generally thought to have the same "fast-spiking" phenotype, which is characterized by a short action potential and high frequency firing without adaptation. However, findings from studies in different species suggest that certain electrophysiological membrane properties might differ between these two cell classes. In this study, we assessed the physiological heterogeneity of fast-spiking interneurons as a function of two factors: species (macaque monkey vs. rat) and morphology (chandelier vs. basket). We showed previously that electrophysiological membrane properties of BCs differ between these two species. Here, for the first time, we report differences in ChCs membrane properties between monkey and rat. We also found that a number of membrane properties differentiate ChCs from BCs. Some of these differences were species-independent (e.g., fast and medium afterhyperpolarization, firing frequency, and depolarizing sag), whereas the differences in the first spike latency between ChCs and BCs were species-specific. Our findings indicate that different combinations of electrophysiological membrane properties distinguish ChCs from BCs in rodents and primates. Such electrophysiological differences between ChCs and BCs likely contribute to their distinctive roles in cortical circuitry in each species. © 2013 Povysheva et al

Search for a Lorentz invariance violation contribution in atmospheric neutrino oscillations using MACRO data

Neutrino-induced upward-going muons in MACRO have been analysed in terms of relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of nu_mu -> nu_tau transitions. The data disfavor these exotic possibilities even at a sub-dominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter |Delta v| < 6 * 10^(-24) at sin2theta_v = 0 and |Delta v| < 2.5--5 * 10^(-26) at sin2theta_v = +/-1. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the Equivalence Principle.Comment: 8 pages, 2 figures, submitted to Physics Letters

Quality of Life and Work Productivity Improvements with Upadacitinib: Phase 2b Evidence from Patients with Moderate to Severe Crohn’s Disease

Introduction: In the phase 2 CELEST study, positive efficacy results were obtained with the Janus kinase 1 inhibitor upadacitinib for adult patients with moderate to severe Crohn’s disease. We present the health-related quality of life and work productivity improvement results with upadacitinib from CELEST. Methods: CELEST (NCT02365649) was a double-blind study where patients were randomized 1:1:1:1:1:1 in the 16-week induction period to placebo or upadacitinib 3 mg twice daily (BID), 6 mg BID, 12 mg BID, 24 mg BID, or 24 mg once daily (QD). Patients completing the induction period were re-randomized 1:1:1 to receive upadacitinib 3 mg BID, 12 mg BID, or 24 mg QD for 36 weeks or 3 mg BID, 6 mg BID, or 12 mg BID (after amendment). Inflammatory Bowel Disease Questionnaire (IBDQ), European Quality of Life-5 Dimensions visual analog scale (EQ-5D VAS), and Work Productivity and Activity Impairment (WPAI) questionnaire outcomes were assessed at baseline and Weeks 8, 16, and 52. Results: At Week 16, a significant percentage (P ≤ 0.05) of patients receiving upadacitinib 6-mg BID dose or higher achieved IBDQ response (IBDQ score change ≥ 16 points; 49%–57% for upadacitinib vs. 24% for placebo) and IBDQ remission, except 24 mg QD (IBDQ score ≥ 170; 26%–39% for upadacitinib vs. 11% for placebo). Greater improvements in IBDQ total score, EQ-5D VAS, and activity impairment from baseline (P ≤ 0.1) versus placebo were also observed. Larger improvements (P ≤ 0.1) in IBDQ response and total score and EQ-5D VAS were observed at Week 8 with 6 and 24 mg BID versus placebo, with improvements for all dosages maintained or greater at Week 52 for IBDQ, EQ-5D VAS, and WPAI endpoints, in particular for the 12-mg BID group. Conclusion: Improvements in health-related quality of life and work productivity were achieved and sustained with upadacitinib in patients with moderate to severe Crohn’s disease. Trial Registration: ClinicalTrials.gov identifier, NCT02365649. © 2021, The Author(s)

Spectroscopic variability of two Oe stars

The Oe stars HD45314 and HD60848 have recently been found to exhibit very different X-ray properties: whilst HD60848 has an X-ray spectrum and emission level typical of most OB stars, HD45314 features a much harder and brighter X-ray emission, making it a so-called gamma Cas analogue. Monitoring the optical spectra could provide hints towards the origin of these very different behaviours. We analyse a large set of spectroscopic observations of HD45314 and HD60848, extending over 20 years. We further attempt to fit the H-alpha line profiles of both stars with a simple model of emission line formation in a Keplerian disk. Strong variations in the strengths of the H-alpha, H-beta, and He I 5876 emission lines are observed for both stars. In the case of HD60848, we find a time lag between the variations in the equivalent widths of these lines. The emission lines are double peaked with nearly identical strengths of the violet and red peaks. The H-alpha profile of this star can be successfully reproduced by our model of a disk seen under an inclination of 30 degrees. In the case of HD45314, the emission lines are highly asymmetric and display strong line profile variations. We find a major change in behaviour between the 2002 outburst and the one observed in 2013. This concerns both the relationship between the equivalent widths of the various lines and their morphologies at maximum strength (double-peaked in 2002 versus single-peaked in 2013). Our simple disk model fails to reproduce the observed H-alpha line profiles of HD45314. Our results further support the interpretation that Oe stars do have decretion disks similar to those of Be stars. Whilst the emission lines of HD60848 are explained by a disk with a Keplerian velocity field, the disk of HD45314 seems to have a significantly more complex velocity field that could be related to the phenomenon that produces its peculiar X-ray emission.Comment: Accepted for Publication in A&

The Rocketbox Library and the Utility of Freely Available Rigged Avatars

As part of the open sourcing of the Microsoft Rocketbox avatar library for research and academic purposes, here we discuss the importance of rigged avatars for the Virtual and Augmented Reality (VR, AR) research community. Avatars, virtual representations of humans, are widely used in VR applications. Furthermore many research areas ranging from crowd simulation to neuroscience, psychology, or sociology have used avatars to investigate new theories or to demonstrate how they influence human performance and interactions. We divide this paper in two main parts: the first one gives an overview of the different methods available to create and animate avatars. We cover the current main alternatives for face and body animation as well introduce upcoming capture methods. The second part presents the scientific evidence of the utility of using rigged avatars for embodiment but also for applications such as crowd simulation and entertainment. All in all this paper attempts to convey why rigged avatars will be key to the future of VR and its wide adoption