In recent years, spin-orbit effects have been widely used to produce and detect spin currents in spintronic devices. The peculiar symmetry of the spin Hall effect allows creation of a spin ...accumulation at the interface between a metal with strong spin-orbit interaction and a magnetic insulator, which can lead to a net pure spin current flowing from the metal into the insulator. This spin current applies a torque on the magnetization, which can eventually be driven into steady motion. Tailoring this experiment on extended films has proven to be elusive, probably due to mode competition. This requires the reduction of both the thickness and lateral size to reach full damping compensation. Here we show clear evidence of coherent spin-orbit torque-induced auto-oscillation in micron-sized yttrium iron garnet discs of thickness 20 nm. Our results emphasize the key role of quasi-degenerate spin-wave modes, which increase the threshold current.
Purpose
To develop an instrument for use at ICU discharge for prediction of psychological problems in ICU survivors.
Methods
Multinational, prospective cohort study in ten general ICUs in secondary ...and tertiary care hospitals in Sweden, Denmark and the Netherlands. Adult patients with an ICU stay ≥ 12 h were eligible for inclusion. Patients in need of neurointensive care, with documented cognitive impairment, unable to communicate in the local language, without a home address or with more than one limitation of therapy were excluded. Primary outcome was psychological morbidity 3 months after ICU discharge, defined as Hospital Anxiety and Depression Scale (HADS) subscale score ≥ 11 or Post-traumatic Stress Symptoms Checklist-14 (PTSS-14) part B score > 45.
Results
A total of 572 patients were included and 78% of patients alive at follow-up responded to questionnaires. Twenty percent were classified as having psychological problems post-ICU. Of 18 potential risk factors, four were included in the final prediction model after multivariable logistic regression analysis: symptoms of depression odds ratio (OR) 1.29, 95% confidence interval (CI) 1.10–1.50, traumatic memories (OR 1.44, 95% CI 1.13–1.82), lack of social support (OR 3.28, 95% CI 1.47–7.32) and age (age-dependent OR, peak risk at age 49–65 years). The area under the receiver operating characteristics curve (AUC) for the instrument was 0.76 (95% CI 0.70–0.81).
Conclusions
We developed an instrument to predict individual patients’ risk for psychological problems 3 months post-ICU,
http://www.imm.ki.se/biostatistics/calculators/psychmorb/
. The instrument can be used for triage of patients for psychological ICU follow-up.
Trial registration
The study was registered at clinicaltrials.gov, NCT02679157.
The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the ...glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the Little Ice Age (LIA, mid-17th-early 18th century). In terms of changes in mass balance, although there have been some sporadic gains on several glaciers, we show that the trend has been quite negative over the past 50 yr, with a mean mass balance deficit for glaciers in the tropical Andes that is slightly more negative than the one computed on a global scale. A break point in the trend appeared in the late 1970s with mean annual mass balance per year decreasing from -0.2 m w.e. in the period 1964-1975 to -0.76 m w.e. in the period 1976-2010. In addition, even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia show that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance at the decadal timescale. Precipitation did not display a significant trend in the tropical Andes in the 20th century, and consequently cannot explain the glacier recession. On the other hand, temperature increased at a significant rate of 0.10 degree C decade super(-1) in the last 70 yr. The higher frequency of El Nino events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may thus explain much of the recent dramatic shrinkage of glaciers in this part of the world.
The wave dissipation properties of layered periodic structures are modelled by FE as well as analytical approaches. A linear oscillator incorporating a negative stiffness element and having ...exceptional energy dissipation properties is exhibited and incorporated within the modelled structures. The structural dynamic stability of both the oscillator and the modelled waveguides is discussed and ensured. The numerical results provide evidence of a drastic increase of several orders of magnitude for the damping ratio of the flexural waves propagating within the structures.
•Wave dissipation is modelled within continuous and layered periodic structures.•Analytical approaches as well as periodic structure theory are employed.•The structural dynamic stability is discussed and ensured.•An increase of several orders of magnitude for the wave damping ratio is observed.
The present paper aims to apply the concept of energy pumping for noise reduction at propagation and reception paths. This phenomenon consists in irreversible energy transfer from a linear primary ...system to a nonlinear energy sink, where the energy is finally dissipated. In this study, we turn a loudspeaker to an electroacoustic absorber by connecting at its transducers terminals a passive nonlinear shunt circuit playing the role of an absorber. The equivalent model consists of a linear structure describing the displacement of the loudspeaker, linearly coupled to a cubic nonlinear energy sink. For the case of 1:1 resonance, the Invariant manifold approach is applied for different time scales. It enables the detection of the slow invariant manifold and equilibrium and fold singularities at the fast and slow time scales respectively. This methodology provides a predictive tool allowing the design of the nonlinear energy sink for better control of the main system. The analytical and numerical results show that the nonlinear shunt circuit managed to expand the frequency band of the controlled system.
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