Distributed algorithms for nonlinear tree-sparse problems

[no abstract

Comment on "Two-Dimensional Optical Control of Electron Spin Orientation by Linearly Polarized Light in InGaAs"

[No abstract available

Understanding the Characteristics of Frequent Users of Emergency Departments : What Role Do Medical Conditions Play?

Frequent users of emergency departments (ED) pose a significant challenge to hospital emergency services. Despite a wealth of studies in this field, it is hardly understood, what medical conditions lead to frequent attendance. We examine (1) what ambulatory care sensitive conditions (ACSC) are linked to frequent use, (2) how frequent users can be clustered into subgroups with respect to their diagnoses, acuity and admittance, and (3) whether frequent use is related to higher acuity or admission rate. We identified several ACSC that highly increase the risk for heavy ED use, extracted four major diagnose subgroups and found no significant effect neither for acuity nor admission rate. Our study indicates that especially patients in need of (nursing) care form subgroups of frequent users, which implies that quality of care services might be crucial for tackling frequent use. Hospitals are advised to regularly analyze their ED data in the EHR to better align resources

Optical Spin Noise of a Single Hole Spin Localized in an (InGa)As Quantum Dot

We advance spin noise spectroscopy to the ultimate limit of single spin detection. This technique enables the measurement of the spin dynamic of a single heavy hole localized in a flat (InGa)As quantum dot. Magnetic field and light intensity dependent studies reveal even at low magnetic fields a strong magnetic field dependence of the longitudinal heavy hole spin relaxation time with an extremely long $T_1$ of $\ge$ 180 $\mu$s at 31 mT and 5 K. The wavelength dependence of the spin noise power discloses for finite light intensities an inhomogeneous single quantum dot spin noise spectrum which is explained by charge fluctuations in the direct neighborhood of the quantum dot. The charge fluctuations are corroborated by the distinct intensity dependence of the effective spin relaxation rate

Use of Emergency Departments by Frail Elderly Patients : Temporal Patterns and Case Complexity

Emergency department (ED) care for frail elderly patients is associated with an increased use of resources due to their complex medical needs and frequently difficult psycho-social situation. To better target their needs with specially trained staff, it is vital to determine the times during which these particular patients present to the ED. Recent research was inconclusive regarding this question and the applied methods were limited to coarse time windows. Moreover, there is little research on time variation of frail ED patients’ case complexity. This study examines differences in arrival rates for frail vs. non-frail patients in detail and compares case complexity in frail patients within vs. outside of regular GP working hours. Arrival times and case variables (admission rate, ED length of stay [LOS], triage level and comorbidities) were extracted from the EHR of an ED in an urban German teaching hospital. We employed Poisson time series regression to determine patterns in hourly arrival rates over the week. Frail elderly patients presented more likely to the ED during already high frequented hours, especially at midday and in the afternoon. Case complexity for frail patients was significantly higher compared to non-frail patients, but varied marginally in time only with respect to triage level and ED LOS. The results suggest that frailty-attuned emergency care should be available in EDs during the busiest hours. Based on EHR data, hospitals thus can tailor their staff needs

Model-Driven User Interface Generation and Adaptation in Process-Aware Information Systems

The increasing adoption of process-aware information systems (PAISs) has resulted in a large number of implemented business processes. To react on changing needs, companies should be able to quickly adapt these process implementations if required. Current PAISs, however, only provide mechanisms to evolve the schema of a process model, but do not allow for the automated creation and adaptation of their user interfaces (UIs). The latter may have a complex logic and comprise, for example, conditional elements or database queries. Creating and evolving the UI components of a PAIS manually is a tedious and error-prone task. This technical report introduces a set of patterns for transforming fragments of a business process model, whose activities are performed by the same user role, to UI components of the PAIS. In particular, UI logic can be expressed using the same notation as for process modeling. Furthermore, a transformation method is introduced, which applies these patterns to automatically derive UI components from a process model by establishing a bidirectional mapping between process model and UI. This mapping allows propagating UI changes to the process model and vice versa. Overall, our approach enables process designers to rapidly develop and update complex UI components in PAISs

Spin noise spectroscopy in GaAs (110) quantum wells: Access to intrinsic spin lifetimes and equilibrium electron dynamics

In this letter, the first spin noise spectroscopy measurements in semiconductor systems of reduced effective dimensionality are reported. The non-demolition measurement technique gives access to the otherwise concealed intrinsic, low temperature electron spin relaxation time of n-doped GaAs (110) quantum wells and to the corresponding low temperature anisotropic spin relaxation. The Brownian motion of the electrons within the spin noise probe laser spot becomes manifest in a modification of the spin noise line width. Thereby, the spatially resolved observation of the stochastic spin polarization uniquely allows to study electron dynamics at equilibrium conditions with a vanishing total momentum of the electron system

GHz Spin Noise Spectroscopy in n-Doped Bulk GaAs

We advance spin noise spectroscopy to an ultrafast tool to resolve high frequency spin dynamics in semiconductors. The optical non-demolition experiment reveals the genuine origin of the inhomogeneous spin dephasing in n-doped GaAs wafers at densities at the metal-to-insulator transition. The measurements prove in conjunction with depth resolved spin noise measurements that the broadening of the spin dephasing rate does not result from thermal fluctuations or spin-phonon interaction, as previously suggested, but from surface electron depletion