Simultaneous planar growth of amorphous and crystalline Ni silicides

We report a solid-state interdiffusion reaction induced by rapid thermal annealing and vacuum furnace annealing in evaporated Ni/Si bilayers. Upon heat treatment of a Ni film overlaid on a film of amorphous Si evaporated from a graphite crucible, amorphous and crystalline silicide layers grow uniformly side by side as revealed by cross-sectional transmission electron microscopy and backscattering spectrometry. This phenomenon contrasts with the silicide formation behavior previously observed in the Ni-Si system, and constitutes an interesting counterpart of the solid-state interdiffusion-induced amorphization in Ni/Zr thin-film diffusion couples. Carbon impurity contained in the amorphous Si film stabilizes the amorphous phase. Kinetic and thermodynamic factors that account for the experimental findings are discussed

The Power of Optimization Over Randomization in Designing Experiments Involving Small Samples

Random assignment, typically seen as the standard in controlled trials, aims to make experimental groups statistically equivalent before treatment. However, with a small sample, which is a practical reality in many disciplines, randomized groups are often too dissimilar to be useful. We propose an approach based on discrete linear optimization to create groups whose discrepancy in their means and variances is several orders of magnitude smaller than with randomization. We provide theoretical and computational evidence that groups created by optimization have exponentially lower discrepancy than those created by randomization and that this allows for more powerful statistical inference.National Science Foundation (U.S.). Graduate Research Fellowship (Grant 1122374

The Uncertainty Aware Salted Kalman Filter: State Estimation for Hybrid Systems with Uncertain Guards

In this paper we present a method for updating robotic state belief through contact with uncertain surfaces and apply this update to a Kalman filter for more accurate state estimation. Examining how guard surface uncertainty affects the time spent in each mode, we derive a guard saltation matrix - which maps perturbations prior to hybrid events to perturbations after - accounting for additional variation in the resulting state. Additionally, we propose the use of parameterized reset functions - capturing how unknown parameters change how states are mapped from one mode to the next - the Jacobian of which accounts for the additional uncertainty in the resulting state. The accuracy of these mappings is shown by simulating sampled distributions through uncertain transition events and comparing the resulting covariances. Finally, we integrate these additional terms into the "uncertainty aware Salted Kalman Filter", uaSKF, and show a peak reduction in average estimation error by 24-60% on a variety of test conditions and systems.Comment: To appear in IROS 202

What very small numbers mean.

This article presents a theoretical and experimental framework for assessing the biases associated with the interpretation of numbers. This framework consists of having participants convert between different representations of quantities. These representations should include both variations in numerical labels that symbolize quantities and variations in displays in which quantity is inherent. Five experiments assessed how people convert between relative frequencies, decimals, and displays of dots that denote very low proportions (i.e., proportions below 1%). The participants demonstrated perceptual, response, and numerical transformation biases. Furthermore, the data suggest that relative frequencies and decimals are associated with different abstract representations of amount. Scientists and lay people use several numerical formats (i.e., any symbol system used to represent quantities) to symbolize propor-tions. For example, the decimal “0.5 ” and relative frequency “1 in 2 ” symbolize the same proportion. Although relative frequencies and decimals denote proportions equally well, people may inter-pret these numerical formats differently. Nevertheless, researchers often make an implicit assumption that people interpret these numerical formats equivalently (termed the assumption of numer-ical equivalence). The implicit assumption of numerical equiva-lence is prevalent in studies of psychophysics (e.g., Gescheider

From Social Exclusion to Supported Inclusion: Adults with Intellectual Disability Discuss Their Lived Experiences of a Sructured Social Group

Background People with intellectual disability often have few friends and experience social exclusion. Recognising this gap, supported social groups with the aim of inclusion and interdependence were created by a supported employment provider. Methods Interviews were undertaken with 10 adults with intellectual disability exploring their lived experiences of a supported social group. Data were analysed using descriptive phenomenology. Results Two themes emerged (i) supported engagement fosters wellbeing, and (ii) developing social belonging and connectedness. Participants not only acknowledged the support that they needed to participate, but also that the social group had changed their lives in many ways. Conclusions Adults with intellectual disability want to socialise, have friends and be part of their community. For this to be achieved, they recognise the need to seek some form of support. With appropriate and targeted support, adults with intellectual disability can move from social exclusion towards supported inclusion and experience richer lives

Radio-Optical Reference Catalog, version 1

The fundamental celestial reference frame (CRF) is based on two catalogs of astrometric positions, the third realization of the International Celestial Reference Frame (ICRF3), and the much larger Gaia~CRF, built from the third data release (DR3). The objects in common between these two catalogs are mostly distant AGNs and quasars that are both sufficiently optically bright for Gaia and radio-loud for the VLBI. This limited collection of reference objects is crucially important for the mutual alignment of the two CRFs and maintenance of all the other frames and coordinate systems branching from the ICRF. In this paper, we show that the three components of ICRF3 (S/X, K, and X/Ka band catalogs) have significantly different sky-correlated vector fields of position offsets with respect to Gaia~DR3. When iteratively expanded in the vector spherical harmonics up to degree 4 on a carefully vetted set of common sources, each of these components includes several statistically significant terms. The median sky-correlated offsets from the Gaia positions are found to be 56 $\mu$as for the S/X, 100 $\mu$as for the K, and 324 $\mu$as for the Ka catalogs. The weighted mean vector field is subtracted from the Gaia reference positions, while the deviations from that field are added to each of the ICRF3 components. The corrected positions from each of the four input catalogs are combined into a single weighted mean catalog, which we propose to be the current most accurate realization of an inertial radio-optical CRF.Comment: To be published in A