Maximum Agreement Linear Prediction via the Concordance Correlation Coefficient

This paper examines distributional properties and predictive performance of the estimated maximum agreement linear predictor (MALP) introduced in Bottai, Kim, Lieberman, Luta, and Pena (2022) paper in The American Statistician, which is the linear predictor maximizing Lin's concordance correlation coefficient (CCC) between the predictor and the predictand. It is compared and contrasted, theoretically and through computer experiments, with the estimated least-squares linear predictor (LSLP). Finite-sample and asymptotic properties are obtained, and confidence intervals are also presented. The predictors are illustrated using two real data sets: an eye data set and a bodyfat data set. The results indicate that the estimated MALP is a viable alternative to the estimated LSLP if one desires a predictor whose predicted values possess higher agreement with the predictand values, as measured by the CCC

Hybrid top-down/bottom-up fabrication of a highly uniform and organized faceted AlN nanorod scaffold

As a route to the formation of regular arrays of AlN nanorods, in contrast to other III-V materials, the use of selective area growth via metal organic vapor phase epitaxy (MOVPE) has so far not been successful. Therefore, in this work we report the fabrication of a highly uniform and ordered AlN nanorod scaffold using an alternative hybrid top-down etching and bottom-up regrowth approach. The nanorods are created across a full 2-inch AlN template by combining Displacement Talbot Lithography and lift-offto create a Ni nanodot mask, followed by chlorine-based dry etching. Additional KOH-based wet etching is used to tune the morphology and the diameter of the nanorods. The resulting smooth and straight morphology of the nanorods after the two-step dry-wet etching process is used as a template to recover the AlN facets of the nanorods via MOVPE regrowth. The facet recovery is performed for various growth times to investigate the growth mechanism and the change in morphology of the AlN nanorods. Structural characterization highlights, first, an efficient dislocation filtering resulting from the ~130 nm diameter nanorods achieved after the two-step dry-wet etching process, and second, a dislocation bending induced by the AlN facet regrowth. A strong AlN near band edge emission is observed from the nanorods both before and after regrowth. The achievement of a highly uniform and organized faceted AlN nanorod scaffold having smooth and straight non-polar facets and improved structural and optical quality is a major stepping stone toward the fabrication of deep UV core-shell-based AlN or AlxGa1-xN templates

Ultra‐thin GaAs solar cells with nanophotonic metal‐dielectric diffraction gratings fabricated with displacement Talbot lithography

Funder: Cambridge Trust; Id: http://dx.doi.org/10.13039/501100003343Funder: Consejo Nacional de Ciencia y Tecnología; Id: http://dx.doi.org/10.13039/501100003141Funder: Isaac Newton Trust; Id: http://dx.doi.org/10.13039/501100004815Abstract: Ultra‐thin photovoltaics enable lightweight flexible form factors, suitable for emerging terrestrial applications such as electric vehicle integration. These devices also exhibit intrinsic radiation tolerance and increased specific power and so are uniquely enabling for space power applications, offering longer missions in hostile environments and reduced launch costs. In this work, a GaAs solar cell with an 80‐nm absorber is developed with short circuit current exceeding the single pass limit. Integrated light management is employed to compensate for increased photon transmission inherent to ultra‐thin absorbers, and efficiency enhancement of 68% over a planar on‐wafer equivalent is demonstrated. This is achieved using a wafer‐scale technique, displacement Talbot lithography, to fabricate a rear surface nanophotonic grating. Optical simulations definitively confirm Fabry‐Perot and waveguide mode contributions to the observed increase in absorption and also demonstrate a pathway to short circuit current of 26 mA/cm2, well in excess of the double pass limit

Hybrid top-down/bottom-up fabrication of regular arrays of AlN nanorods for deep-UV core-shell LEDs

Core–shell nanostructures are predicted to highly improve the efficiency of deep-UV light emitting diodes (LEDs), owing to their low defect density, reduced quantum-confined Stark effect, high-quality non-polar growth and improved extraction efficiency. In this paper, we report on the nanofabrication of high-quality AlN nanorod arrays using a hybrid top-down/bottom-up approach for use as a scaffold for UV LED structures. We describe the use of Displacement Talbot Lithography to fabricate a metallic hard etch mask to allow AlN nanorod arrays to be dry etched from a planar AlN template. In particular, we investigate the impact of etching parameters on the nanorod etch rate, tapering profile and mask selectivity in order to achieve vertical-sided nanorod arrays with high aspect ratios. AlN facet recovery is subsequently explored by means of regrowth using Metal Organic Vapor Phase Epitaxy. Low pressure and high V/III ratio promote straight and smooth sidewall faceting, which results in an improvement of the optical quality compared to the initial AlN template. The promising results open new perspectives for the fabrication of high-efficiency deep-UV-emitting core–shell LEDs

How to measure sedentary behavior at work?

Background: Prolonged sedentary behavior (SB) is associated with increased risk for chronic conditions. A growing number of the workforce is employed in office setting with high occupational exposure to SB. There is a new focus in assessing, understanding and reducing SB in the workplace. There are many subjective (questionnaires) and objective methods (monitoring with wearable devices) available to determine SB. Therefore, we aimed to provide a global understanding on methods currently used for SB assessment at work.Methods: We carried out a systematic review on methods to measure SB at work. Pubmed, Cochrane, Embase, and Web of Science were searched for peer-reviewed English-language articles published between 1st January 2000 and 17th March 2019.Results: We included 154 articles: 89 were cross-sectional and 65 were longitudinal studies, for a total of 474,091 participants. SB was assessed by self-reported questionnaires in 91 studies, by wearables devices in also 91 studies, and simultaneously by a questionnaire and wearables devices in 30 studies. Among the 91 studies using wearable devices, 73 studies used only one device, 15 studies used several devices, and three studies used complex physiological systems. Studies exploring SB on a large sample used significantly more only questionnaires and/or one wearable device.Conclusions: Available questionnaires are the most accessible method for studies on large population with a limited budget. For smaller groups, SB at work can be objectively measured with wearable devices (accelerometers, heart-rate monitors, pressure meters, goniometers, electromyography meters, gas-meters) and the results can be associated and compared with a subjective measure (questionnaire). The number of devices worn can increase the accuracy but make the analysis more complex and time consuming

Dataset for "Spatial periodicities inside the Talbot effect: understanding, control and applications for lithography"

This dataset contains the data used to create the figures within the article "Spatial periodicities inside the Talbot effect: understanding, control and applications for lithography" by Pierre Chausse and Philip Shields. The data comprises one-dimensional and two-dimensional data showing the spatial variation of the light intensity behind grating masks that are illuminated with collimated 375 nm optical radiation. The grating mask period has been varied from 600 nm to 1200 nm.A MATLAB computer model was developed to simulate the operation of a DTL machine in which the light source is a 375 nm UV laser. An optical system generates a plane wave illuminating a conventional lithography mask at normal incidence so that the light arriving at the mask is homogeneous, unpolarised, and in phase. The complex electric field is derived using Fast Fourier Transform (FFT) of the electric field of the mask. As periodic masks are mandatory for DTL, periodic boundary conditions can be applied. Contributions from the different mask regions, propagating behind it, are given amplitudes of 1 and 0 for a chrome amplitude mask, and 1 and -1 for a phase mask. The integration of the three-dimensional light known as the Talbot carpet is then performed. The electric field is multiplied by its conjugate to obtain the surface light intensity.The simulations were performed within MATLAB.Within the main .rar file, each figure has its own compressed .rar file. In each of these, the final figure in .jpg is included, along with the source figure or subfigures in both .tif and MATLAB proprietary .fig formats. The underlying data has also been exported in CSV format. In the data folder for figure 1, there are two CSV files: - x.csv corresponds to the x-axis value for each curve; - y.csv contains the values of the different spatial periodicity, where NaN means no value. For all the other figures, each subfigure is accompanied by two or three CSV files: - x.csv is the x-axis points value; - y.csv is the y-axis points value; - Data.csv corresponds to the matrix data, where applicable

Calcul quantique de l’anisotropie magnétique de bandes graphitiques

L’application de la méthode de LONDON au calcul de l'ani- sotropie magnétique de bandes graphitiques planes de largeur limitée (à 0 °K) conduit à des formules analytiques générales grâce à un choix convenable des conditions aux limites (lorsque l’on suppose que le champ magnétique tend vers 0).Les résultats permettent d’interpréter la variation importante de susceptibilité observée expérimentalement en fonction de la largeur des crislallites graphitiques formant les carbones prégraphitiques, mais conduisent à une anisotropic infinie pour un plan graphitique illimité.On donne également quelques caractéristiques de ces bandes en l’absence de champ magnétique (largeur de la bande interdite, énergie de résonance, indice de liaison mobile)