Superconducting spintronic tunnel diode.

Diodes are key elements for electronics, optics, and detection. Their evolution towards low dissipation electronics has seen the hybridization with superconductors and the realization of supercurrent diodes with zero resistance in only one direction. Here, we present the quasi-particle counterpart, a superconducting tunnel diode with zero conductance in only one direction. The direction-selective propagation of the charge has been obtained through the broken electron-hole symmetry induced by the spin selection of the ferromagnetic tunnel barrier: a EuS thin film separating a superconducting Al and a normal metal Cu layer. The Cu/EuS/Al tunnel junction achieves a large rectification (up to ∼40%) already for a small voltage bias (∼200 µV) thanks to the small energy scale of the system: the Al superconducting gap. With the help of an analytical theoretical model we can link the maximum rectification to the spin polarization (P) of the barrier and describe the quasi-ideal Shockley-diode behavior of the junction. This cryogenic spintronic rectifier is promising for the application in highly-sensitive radiation detection for which two different configurations are evaluated. In addition, the superconducting diode may pave the way for future low-dissipation and fast superconducting electronics.

Healthcare attendance styles among long-term unemployed people with substance-related and mood disorders.

BACKGROUND: Both increased and decreased health service usage and unmet care needs are more prevalent among unemployed people than in the general population. STUDY DESIGN: This study investigates the associations of substance-related and mood disorders among long-term unemployed people with styles of healthcare attendance in Finland. METHODS: The study material consisted of the health register information on 498 long-term unemployed people in a project screening for work disabilities. The data were analysed by mixed methods: qualitative typological analysis was applied to identify differential healthcare attendance styles, and the associations of the obtained styles with mental health disorders were analysed quantitatively by multinomial logistic regression. RESULTS: Three styles, characterized as smooth, faltering and marginalized, were identified. Compared with participants with the smooth attendance style without mental disorders, those with the faltering style had tenfold relative risk for substance-related disorder and fourfold relative risk for mood disorder. Those with the marginalized style had fivefold relative risk for substance-related disorder and twofold relative risk for mood disorder. Adjusting for background characteristics did not alter the statistical significance of substance-related disorder. In the case of mood disorders, the statistical significance persisted throughout the adjustments in the faltering style. CONCLUSION: Dysfunctional use of health services is more common among people with substance-related or mood disorders, who are at risk of drifting towards long-term unemployment and work disabilities. The early detection of those with faltering or marginalized healthcare attendance style may prevent prolonged unemployment, enable rehabilitation measures and reduce the risk of disability pensions.

Thrombolysis and adjunct anticoagulation in patients with acute basilar artery occlusion.

BACKGROUND AND PURPOSE: Patients suffering from basilar artery occlusion (BAO) and treated with intravenous thrombolysis are, in some centers, started on adjunct anticoagulation in hyperacute settings. We aimed to assess the outcome of such patients and to compare low-molecular weight heparin (LMWH) and unfractionated heparin (UFH) in this context. METHODS: We examined 211 patients with angiography-proven BAO treated with intravenous thrombolysis and either adjunct UFH or LMWH. Main outcome variables were rate of symptomatic intracranial hemorrhage (sICH) according to European Cooperative Acute Stroke Study II criteria and modified Rankin Scale (mRS) at 3 months. RESULTS: The overall rate of sICH was 11.4% and driven by the UFH group (13.3%). None of the LMWH group developed sICH. Recanalization rate did not significantly differ between the LMWH and UFH groups. An additional propensity analysis was made to balance anticoagulation groups regarding baseline characteristics. Propensity analysis showed a significant difference in sICH rate (0.0% vs. 14.8%, P = 0.044) in favor of LMWH. Independent outcome (mRS score 0-2) was achieved in a total of 31.0% and in 44.8% and 29.1% in the LMWH and UFH group, respectively (P = 0.09). Propensity analysis showed a significant difference in the risk of ending up bedridden or dead (mRS score 5-6; 34.5% vs. 63.0%, P = 0.033) in favor of LMWH. CONCLUSIONS: Our study showed a lower rate of sICH and a shift towards improved outcome in thrombolysed patients with BAO treated with LMWH as compared with UFH.

Spin Pumping and Torque Statistics in the Quantum Noise Limit.

We analyze the statistics of charge and energy currents and spin torque in a metallic nanomagnet coupled to a large magnetic metal via a tunnel contact. We derive a Keldysh action for the tunnel barrier, describing the stochastic currents in the presence of a magnetization precessing with the rate Ω. In contrast to some earlier approaches, our result is valid for an arbitrary ratio of ℏΩ/k_{B}T. We illustrate the use of the action by deriving spintronic fluctuation relations, the quantum limit of pumped current noise, and consider the fluctuations in two specific cases: the situation with a stable precession of magnetization driven by spin transfer torque, and the torque-induced switching between the minima of a magnetic anisotropy. The quantum corrections are relevant when the precession rate exceeds the temperature T, i.e., for ℏΩ≳k_{B}T.

Trajectory analyses of sickness absence among industrial and municipal employees.

BACKGROUND: Compared with the public sector, the private sector is more susceptible to changes in the economic environment and associated threats of downsizing, outsourcing and transfers of production. This might be assumed to be associated with more restrictive sickness absence practices. AIMS: To investigate whether this difference is reflected in higher sickness absence rates in the public sector and to explore the potential of trajectory analysis in researching such absences. METHODS: The sample consisted of industrial and municipal employees. Latent groups of differential sickness absence during a 6-year study period were searched with a two-response trajectory analysis that jointly captured the spells and the days. Multinomial logistic regressions were used to assess associations of the labour market sector with the set of trajectories obtained. RESULTS: There were 2207 industrial and 3477 municipal employees in the study group. The analysis assigned the employees to three trajectory groups, the 'low-level', 'middle-range' and 'high-range' groups. The relative risk ratios for the middle-range and the high-range trajectories of public sector employees were not higher after controlling for age, gender and occupational. CONCLUSIONS: In this study, the labour market sector was not a major independent determinant of sickness absence practices. Trajectory analysis can be recommended as a way to determine differential absence practices. The trajectory approach might help occupational health services to identify more accurately the employees who need support to maintain their work ability.

Long-range spin accumulation from heat injection in mesoscopic superconductors with Zeeman splitting.

We describe far-from-equilibrium nonlocal transport in a diffusive superconducting wire with a Zeeman splitting, taking into account different spin relaxation mechanisms. We demonstrate that due to the Zeeman splitting, an injection of current in a superconducting wire creates spin accumulation that can only relax via thermalization. This effect leads to a long-range spin accumulation detectable in the nonlocal signal. Our model gives a qualitative explanation and provides accurate fits of recent experimental results in terms of realistic parameters.

Predicted very large thermoelectric effect in ferromagnet-superconductor junctions in the presence of a spin-splitting magnetic field.

We show that a huge thermoelectric effect can be observed by contacting a superconductor whose density of states is spin split by a Zeeman field with a ferromagnet with a nonzero polarization. The resulting thermopower exceeds kB/e by a large factor, and the thermoelectric figure of merit ZT can far exceed unity, leading to heat engine efficiencies close to the Carnot limit. We also show that spin-polarized currents can be generated in the superconductor by applying a temperature bias.

Multi-site pain and working conditions as predictors of work ability in a 4-year follow-up among food industry employees.

BACKGROUND: We investigated the separate and joint effects of multi-site musculoskeletal pain and physical and psychosocial exposures at work on future work ability. METHODS: A survey was conducted among employees of a Finnish food industry company in 2005 (n = 1201) and a follow-up survey in 2009 (n = 734). Information on self-assessed work ability (current work ability on a scale from 0 to 10; 7 = poor work ability), multi-site musculoskeletal pain (pain in at least two anatomical areas of four), leisure-time physical activity, body mass index and physical and psychosocial exposures was obtained by questionnaire. The separate and joint effects of multi-site pain and work exposures on work ability at follow-up, among subjects with good work ability at baseline, were assessed by logistic regression, and p-values for the interaction derived. RESULTS: Compared with subjects with neither multi-site pain nor adverse work exposure, multi-site pain at baseline increased the risk of poor work ability at follow-up, allowing for age, gender, occupational class, body mass index and leisure-time physical activity. The separate effects of the work exposures on work ability were somewhat smaller than those of multi-site pain. Multi-site pain had an interactive effect with work environment and awkward postures, such that no association of multi-site pain with poor work ability was seen when work environment was poor or awkward postures present. CONCLUSIONS: The decline in work ability connected with multi-site pain was not increased by exposure to adverse physical or psychosocial factors at work.

Health status and health behaviour as predictors of the occurrence of unemployment and prolonged unemployment.

OBJECTIVES: Earlier research on health-related selection into unemployment has been based on relatively severe health problems, leaves questions unanswered about particular problems, follow-up times have been short and the measurement of unemployment utilised has been crude. The present study explores the effects of suboptimal health on employment in the long term, with statistics that enable assessment of the occurrence and extent of unemployment. STUDY DESIGN: Employment status of a population cohort (n = 1083) was measured half-yearly from 18 to 42 years of age with four follow-up surveys. METHODS: Health status at 30 years of age was assessed with nine indicators. Their associations with the occurrence of a period of unemployment during the subsequent 12 years were analysed with Cox proportional hazard models, and generalized linear models were applied in assessing their associations with prolonged unemployment. RESULTS: Suboptimal self-rated health and suboptimal mood were the most robust predictors of both occurrence of unemployment {hazard rates 1.48 [95% confidence interval (CI) 1.13-1.94] and 1.59 (95% CI 1.19-2.12), respectively} and prolonged unemployment [risk ratios 1.95 (95% CI 1.66-2.29) and 1.44 (95% CI 1.24-1.67), respectively]. Significant associations, particularly with prolonged unemployment, were also seen for musculoskeletal pain, suboptimal sense functions and sleep quality, and smoking and risky alcohol intake. CONCLUSIONS: There is health-related selection into unemployment in early middle age, irrespective of unemployment earlier in the life course. High risk ratios for prolonged unemployment suggest that selection takes place, in particular, at re-employment. The findings indicate the need for policies to prevent those with a history of health problems being at a disadvantage in terms of future employment.

Absorption of heat into a superconductor-normal metal-superconductor junction from a fluctuating environment.

We study a diffusive superconductor-normal-metal-superconductor junction in an environment with intrinsic incoherent fluctuations which couple to the junction through an electromagnetic field. When the temperature of the junction differs from that of the environment, this coupling leads to an energy transfer between the two systems, taking the junction out of equilibrium. We describe this effect in the linear response regime and show that the change in the supercurrent induced by this coupling leads to qualitative changes in the current-phase relation and, for a certain range of parameters, an increase in the critical current of the junction. In addition to normal metals, similar effects can be expected also in other conducting weak links.

Multi-site pain and work ability among an industrial population.

BACKGROUND: Multi-site pain is a common phenomenon among working-age people and it strongly increases work disability risk. Little is known about the impact of musculoskeletal pain on work ability. AIMS: To investigate whether the number of musculoskeletal pain sites predicts future poor work ability. METHODS: The study was conducted in 2005 and 2009 in a food processing company. A total of 734 workers participated in the study. The information on self-perceived work ability and musculoskeletal pain during the preceding week was obtained through a structured questionnaire distributed to employees. The risk of poor work ability at follow-up related to the number of pain sites at baseline was estimated with logistic regression. RESULTS: The proportion of poor work ability increased in 4 years from 15 to 22%, parallel to the increase in the number of pain sites. Among those with 'non-poor' work ability at baseline, one-tenth reported their work ability to be poor after 4 years. The number of pain sites predicted poor work ability after 4 years of follow-up with a dose-response manner. Those with widespread pain had almost a 3-fold risk of developing poor work ability at follow-up. The associations were stronger for younger and white-collar workers. CONCLUSIONS: The results of the present study indicate that multi-site musculoskeletal pain at baseline strongly predicts poor work ability after 4 years among industrial workers. Counting the number of concurrent pain sites may be a simple method of identifying workers with high risk of work disability in occupational health practice.

Absenteeism following a workplace intervention for older food industry workers.

BACKGROUND: The effects of workplace interventions on sickness absence are poorly understood, in particular in ageing workers. AIMS: To analyse the effects of a senior programme on sickness absence among blue-collar food industry workers of a food company in Finland. METHODS: We followed up 129 employees aged 55 years or older, who participated in a senior programme (intervention group), and 229 employees of the same age from the same company who did not participate (control group). Total sickness absence days and spells of 1-3, 4-7, 8-21 and >21 days were recorded for the members of the intervention group from the year before joining the programme and for the control group starting at age 54 years. Both groups were followed for up to 6 years. RESULTS: The median number of sickness absence days per person-year increased significantly from baseline in both groups during the follow-up. Compared with the control group, the intervention group had increased risk for 1-3 days spells [rate ratio 1.34 (1.21-1.48)] and 4-7 days spells [rate ratio 1.23 (1.07-1.41)], but the risk for >21 days spells was decreased [rate ratio 0.68 (0.53-0.88)] after participation in the senior programme. CONCLUSIONS: A programme to enhance individual work well-being in ageing workers may increase short-term but reduce long-term sickness absence.

Stressful life events and the onset of asthma.

The status of stressful life events as a risk factor for asthma is unclear and may be dependent on pre-existing allergic rhinitis. This study examined whether exposure to stressful life events predicted the onset of asthma in adults. This is a prospective, population-based cohort study of 16,881 males and females, aged 20-54 yrs and free of diagnosed asthma at the beginning of the follow-up (January 1, 2004). Data about stressful life events were gathered with a postal survey. The onset of asthma was ascertained through national registers until December 31, 2005. During the follow-up period, 192 incident cases of asthma were identified. High total exposure to stressful life events, as indicated by a cumulative severity score, predicted the onset of asthma (hazard ratio 1.96, 95% CI 1.22-3.13). This association was robust to adjustment for demographics, smoking and having a cat/dog at home and it was observed both among those with and without allergic rhinitis at baseline. Of the 10 most stressful life events, the illness of a family member, marital problems, divorce or separation and conflicts with a supervisor were associated with the onset of asthma. Our study suggests that stressful life events may increase the onset of asthma.

Probing the dynamics of Andreev states in a coherent normal/superconducting ring.

The supercurrent that establishes between two superconductors connected through a normal N mesoscopic link is carried by quasiparticule states localized within the link, the "Andreev bound states (ABS)". Whereas the dc properties of this supercurrent in SNS junctions are now well understood, its dynamical properties are still an unresolved issue. In this letter we probe this dynamics by inductively coupling an NS ring to a multimode superconducting resonator, thereby implementing both a phase bias and current detection at high frequency. Whereas at very low temperatures we essentially measure the phase derivative of the supercurrent, at higher temperature we find a surprisingly strong frequency dependence in the current response of the ring: the ABS do not follow adiabatically the phase modulation. This experiment also illustrates a new tool to probe the fundamental time scales of phase coherent systems that are decoupled from macroscopic normal contacts and thermal baths.

Theory of microwave-assisted supercurrent in quantum point contacts.

We present a microscopic theory of the effect of a microwave field on the supercurrent through a quantum point contact of arbitrary transmission. Our theory predicts that (i) for low temperatures and weak fields, the supercurrent is suppressed at certain values of the superconducting phase, (ii) at strong fields, the current-phase relation is strongly modified and the current can even reverse its sign, and (iii) at finite temperatures, the microwave field can enhance the critical current of the junction. Apart from their fundamental interest, our findings are also important for the description of experiments that aim at the manipulation of the quantum state of atomic point contacts.

Thermal conductance by the inverse proximity effect in a superconductor.

We study heat transport in hybrid lateral normal-metal-superconductor-normal-metal structures. We find the thermal conductance of a short superconducting wire to be strongly enhanced beyond the BCS value due to the inverse proximity effect, resulting from contributions of elastic cotunneling and crossed Andreev reflection of quasiparticles. Our measurements agree with a model based on the quasiclassical theory of inhomogeneous superconductivity in the diffusive limit.

Work stress and health in primary health care physicians and hospital physicians.

OBJECTIVE: In order to understand the reasons for the low priority given to work in primary health care among physicians, we studied differences in work stress, health and health related lifestyles between general practitioners (GPs) and hospital physicians. METHOD: A cohort of 226 GPs and 523 consultants from Finland responded to a questionnaire survey. The responses were linked to data on registered sickness absence. RESULTS: Compared with consultants, GPs reported higher job strain (OR 1.76, 95% CI 1.23 to 2.53) and perceived work overload (OR 2.29, 95% CI 1.65 to 3.16) but were less likely to report poor team climate (OR 0.65, 95% CI 0.46 to 0.91), procedural injustice (OR 0.49, 95% CI 0.34 to 0.72) and interactional injustice (OR 0.62, 95% CI 0.44 to 0.88). There were only small differences in lifestyle, perceived health, psychological distress and long sick leaves between GPs and consultants. Short sick leaves were more common among GPs, but this difference disappeared after controlling for work characteristics. CONCLUSION: In relation to the current recruitment crisis in primary health care and the studied working conditions, job strain and heavy workload outweigh the attractiveness of a good working climate and low organisational injustice. The non-significant differences in health may indicate that there are no differences in total work stress between GPs and consultants. In tackling the recruitment problems in the field of health care, it is of particular importance to be aware of the sector specific difficulties in working conditions.

Phase states of multiterminal mesoscopic normal-metal-superconductor structures.

We study a mesoscopic normal-metal structure with four superconducting contacts, two of which are joined into a loop. The structure undergoes transitions between three (meta)stable states, with different phase configurations triggered by nonequilibrium conditions. These transitions result in spectacular changes in the magnetoresistance. We find a qualitative agreement between the experiments and a theory based on the quasiclassical Keldysh formalism.

Sickness absence as a risk factor for job termination, unemployment, and disability pension among temporary and permanent employees.

OBJECTIVES: This study examined sickness absence as a risk factor for job termination, unemployment, and disability pension among temporary and permanent workers. METHODS: Prospective cohort study with data on employment contract and sickness absence in 1996, job termination by 1997, and employment status in 1997 and 2000 for 19,093 temporary and 41,530 permanent public sector employees. RESULTS: For women aged 40 years or less and for women over 40, a high sickness absence increased the risk of job termination among temporary employees (OR 1.52 (95% CI 1.36 to 1.71) and OR 1.70 (95% CI 1.36 to 2.13) respectively). High absence was not associated with job termination among men in temporary employment. Among permanent employees, high sickness absence predicted job termination among older, but not among younger employees. Temporary employees with high sickness absence were at the highest risk of immediate unemployment and unemployment three years later. Among older permanent employees, high sickness absence was associated with subsequent work disability pension. CONCLUSIONS: A high rate of sickness absenteeism increases the risk of job termination and unemployment among women in temporary public sector jobs. For permanent employees, secure employment provides protection against unemployment even in the case of high sickness absence.

Economy and job contract as contexts of sickness absence practices: revisiting locality and habitus.

This study revisits two Finnish local governments-Raisio and Nokia-that in an earlier study showed different sickness absence rates in the early 1990s. The locality difference was interpreted sociologically, within a framework inspired by Bourdieu's theory of social field, habitus and practice. The same framework is applied in the present study, starting out from the hypothesis that a constant historical and cultural locality context tends to reproduce prevailing sickness absence practices. The hypothesis was tested by extending the context beyond the locality to the macroeconomic fluctuations that occurred during the 1990s and to the type of employment contract. In both localities a 30% rise was observed in levels of sickness absence from 1991-1993 to 1997-2000. At the beginning of the 1990s the absence rate among permanent employees was 1.86 times higher in Nokia than in Raisio; at the end of the decade the corresponding rate ratio was 1.88. The absence rates were significantly lower among fixed-term employees than permanent employees, but the locality difference was seen in their case, too. Both results support the hypothesis. In spite of major changes taking place in the national economy, the differences between the two towns' sickness absence rates persisted, which in this particular case probably reflects the persisting working-class character of Nokia and middle-class character of Raisio. The theory also applies to the difference between permanent and fixed-term employees: the peripheral power position of the latter on work related social fields leads to the observed practices, i.e. to the relatively low absence rate. The results of our revisit give reason to recapitulate and elaborate upon our theoretical interpretation with a view to deepening our understanding of the social origins of sickness absence practices in the post-industrial workplace, which is characterised by increasing atypical employment and growing job insecurity.