Eye Tracker Accuracy: Quantitative Evaluation of the Invisible Eye Center Location

Purpose. We present a new method to evaluate the accuracy of an eye tracker based eye localization system. Measuring the accuracy of an eye tracker's primary intention, the estimated point of gaze, is usually done with volunteers and a set of fixation points used as ground truth. However, verifying the accuracy of the location estimate of a volunteer's eye center in 3D space is not easily possible. This is because the eye center is an intangible point hidden by the iris. Methods. We evaluate the eye location accuracy by using an eye phantom instead of eyes of volunteers. For this, we developed a testing stage with a realistic artificial eye and a corresponding kinematic model, which we trained with {\mu}CT data. This enables us to precisely evaluate the eye location estimate of an eye tracker. Results. We show that the proposed testing stage with the corresponding kinematic model is suitable for such a validation. Further, we evaluate a particular eye tracker based navigation system and show that this system is able to successfully determine the eye center with sub-millimeter accuracy. Conclusions. We show the suitability of the evaluated eye tracker for eye interventions, using the proposed testing stage and the corresponding kinematic model. The results further enable specific enhancement of the navigation system to potentially get even better results

Upper critical field in {Ba1−x_{1-x}Kx_xBiO3_3}: magnetotransport versus magnetotunneling

Elastic tunneling is used as a powerful direct tool to determine the upper critical field $H_{c2}(T)$ in the high-$T_c$ oxide Ba$_{1-x}$K$_x$BiO$_3$. The temperature dependence of $H_{c2}$ inferred from the tunneling follows the Werthamer-Helfand-Hohenberg prediction for type-II superconductors. A comparison will be made with resistively determined critical field data.Comment: 4 pages incl. 5 figure

Life in 90 words: opportunities for person-centred care amidst COVID-19

Objective: Coronavirus disease 2019 and the consequent public health and social distancing measures significantly impacted on service continuity for mental health patients. This article reports on contingency planning initiative in the Australian public sector. Methods: Ninety-word care synopses were developed for each patient. These formed the basis for guided conversations between case managers and consultant psychiatrists to ensure safe service provision and retain a person-centred focus amidst the threat of major staffing shortfalls. Results: This process identified vulnerable patient groups with specific communication needs and those most at risk through service contraction. The challenges and opportunities for promoting safety and self-management through proactive telehealth came up repeatedly. The guided conversations also raised awareness of the shared experience between patients and professionals of coronavirus disease 2019. Conclusion: There is a parallel pandemic of anxiety which creates a unique opportunity to connect at a human level

PROTECT: Relational Safety based Suicide Prevention Training Frameworks

Preventing suicide is a global priority and staff training is a core prevention strategy. However frontline pressures make translating training into better care and better outcomes difficult. The aim of the paper is to highlight challenges in suicide risk assessment and management and introduce training frameworks to assist with mindful practice so professionals can strike a balance between risk and recovery. We combined the scientific literature with contemporary practice from two successful initiatives from Cambridgeshire, UK; 333 – a recovery oriented model of inpatient/community crisis care and PROMISE – a programme to reduce coercion in care by enhancing patient experience. The resulting PROTECT (PROactive deTECTion) frameworks operationalise ongoing practice of relational safety in these programmes. PROTECT is a combination of novel concepts and adaptations of well-established therapeutic approaches. It has four training frameworks: AWARE for reflection on clinical decisions; DESPAIR for assessment; ASPIRE for management; NOTES for documentation. PROTECT aims to improve self-awareness of mental shortcuts, risk taking thresholds and increase rigour through time efficient crosschecks. The training frameworks should support a relational approach to self-harm/suicide risk detection, mitigation and documentation, making care safer and person-centred. The goal is to enthuse practitioners with recovery oriented practice that draws on the strengths of the person in distress and their natural circle of support. It will provide the confidence to engage in participatory approaches to seek out unique individualised solutions to the overwhelming psychological pain of suicidal distress. Future collaborative research with people with lived and carer experience is needed for fine-tuning

The Star Formation and Extinction Co-Evolution of UV-Selected Galaxies over 0.05<z<1.2

We use a new stacking technique to obtain mean mid IR and far IR to far UV flux ratios over the rest near-UV/near-IR color-magnitude diagram. We employ COMBO-17 redshifts and COMBO-17 optical, GALEX far and near UV, Spitzer IRAC and MIPS Mid IR photometry. This technique permits us to probe infrared excess (IRX), the ratio of far IR to far UV luminosity, and specific star formation rate (SSFR) and their co-evolution over two orders of magnitude of stellar mass and redshift 0.1<z<1.2. We find that the SSFR and the characteristic mass (M_0) above which the SSFR drops increase with redshift (downsizing). At any given epoch, IRX is an increasing function of mass up to M_0. Above this mass IRX falls, suggesting gas exhaustion. In a given mass bin below M_0 IRX increases with time in a fashion consistent with enrichment. We interpret these trends using a simple model with a Schmidt-Kennicutt law and extinction that tracks gas density and enrichment. We find that the average IRX and SSFR follows a galaxy age parameter which is determined mainly by the galaxy mass and time since formation. We conclude that blue sequence galaxies have properties which show simple, systematic trends with mass and time such as the steady build-up of heavy elements in the interstellar media of evolving galaxies and the exhaustion of gas in galaxies that are evolving off the blue sequence. The IRX represents a tool for selecting galaxies at various stages of evolution.Comment: Accepted for publication in GALEX Special Ap.J.Suppl., December, 200

Point-contact-spectroscopy evidence of quasi-particle interactions in RNi2B2C (R=Ho, Y)

The point-contact (PC) d2V/dI2-spectra of HoNi2B2C and YNl2B2C reveal structure at applied voltages corresponding to the phonon frequencies. At about 4 meV a maximum is observed in the phonondensity of states by analogy to the soft-phonon structure in neutron scattering experiments for LuNi2B2C [P. Dervenagas et al., Phys. Rev. B52, R9839 (1995)]and YNl2B2C [H. Kawano et al., Czech. J. Phys. 46, S2-825 (1996), Phys. Rev. Lett.77, 4628 (1996)]. In the Ho compound the low-energy phonon peak is suppressed by an applied magnetic field in an anisotropic way, pointing to an interaction between the phonons and the magnetic systems. Surprisingly, in the nonmagnetic Y compound the 4-meV peak is also suppressed by a magnetic field. In the Ho-compound contacts which show the 〈quasi-thermal〉 behavior, the detailed magnetic-field and temperature dependences of PC spectra suggest that the magnetic order is destroyed due to the coupled phonon-magnon subsystem which is driven out of equilibrium by electrons that pass through the contact, by analogy with the nonequilibrium phonon-induced destruction of the superconducting state in point contacts [I. K. Yanson et al., JETP Lett. 45, 543 (1987)]. The PC electron-phonon interaction(EPI) spectral functions are reconstructed and the estimates for the λ-parameter yield the values of the order of 0.1. Comparison with PC EPI spectra of nonsuperconducting and nonmagnetic LaNi2B2C. [I. K. Yanson et al., Phys. Rev. Lett. 78, 935 (1997)], as well as the comparative study of PC EPI and Andreev-reflection spectra for various contacts with superconducting Ho and Y compounds suggest that the low-energy part of the electron-quasi-particle interaction spectral function is responsible for the Cooper pairing in these materials

Destructive Examination of a SNAP Heat Source

A detailed examination was made of one of three plutonium-238 fueled SNAP 3 heat sources which was shipped from Mound Laboratory in May 1961 and returned in May 1963,. Examination of source included radiography, calorimetry, dimensional inspection, radiation measurements, internal pressure measurements, metallographic examinations of the containers, and recovery and impurity analysis of the plutonium fuel. Results showed that the inner tantalum container of the source failed at the weld, allowing the plutonium to the escape and to attack the Haynes Alloy 25 outer container. Failure at the weld was attributed to the fact that the plutonium had become molten at some time during its use and to poor welding of the liner during fabrication of the source, and not to corrosion of plutonium on the tantalum. It was concluded that tantalum is a satisfactory container material for plutonium at temperature below the melting point of plutonium (640°C)

The mass-dependent star formation histories of disk galaxies: infall model versus observations

We introduce a simple model to explore the star formation histories of disk galaxies. We assume that the disk origins and grows by continuous gas infall. The gas infall rate is parametrized by the Gaussian formula with one free parameter: infall-peak time $t_p$. The Kennicutt star formation law is adopted to describe how much cold gas turns into stars. The gas outflow process is also considered in our model. We find that, at given galactic stellar mass $M_*$, model adopting late infall-peak time $t_p$ results in blue colors, low metallicity, high specific star formation rate and high gas fraction, while gas outflow rate mainly influences the gas-phase metallicity and star formation efficiency mainly influences the gas fraction. Motivated by the local observed scaling relations, we construct a mass-dependent model by assuming low mass galaxy has later infall-peak time $t_p$ and larger gas outflow rate than massive systems. It is shown that this model can be in agreement with not only the local observations, but also the observed correlations between specific star formation rate and galactic stellar mass $SFR/M_* \sim M_*$ at intermediate redshift $z<1$. Comparison between the Gaussian-infall model and exponential-infall model is also presented. It shows that the exponential-infall model predicts higher star formation rate at early stage and lower star formation rate later than that of Gaussian-infall. Our results suggest that the Gaussian infall rate may be more reasonable to describe the gas cooling process than the exponential infall rate, especially for low-mass systems.Comment: 12 pages, 6 figures, ApJ, 2010, 722, 38

Mesoscopic mechanism of exchange interaction in magnetic multilayers

We discuss a mesoscopic mechanism of exchange interaction in ferromagnet-normal metal-ferromagnet multilayers. We show that in the case when the metal's thickness is larger than the electron mean free path, the relative orientation of magnetizations in the ferromagnets is perpendicular. The exchange energy between ferromagnets decays with the metal thickness as a power law