Evidence for the two pole structure of the Lambda(1405) resonance

The K^- p --> pi^0 pi^0 Sigma^0 reaction is studied within a chiral unitary model. The distribution of pi^0 Sigma^0 states forming the Lambda(1405) shows, in agreement with a recent experiment, a peak at 1420 MeV and a relatively narrow width of Gamma = 38 MeV. The mechanism for the reaction is largely dominated by the emission of a pi^0 prior to the K^- p interaction leading to the Lambda(1405). This ensures the coupling of the Lambda(1405) to the K^- p channel, thus maximizing the contribution of the second state found in chiral unitary theories, which is narrow and of higher energy than the nominal Lambda(1405). This is unlike the pi^- p --> K^0 \pi Sigma reaction, which gives more weight to the pole at lower energy and with a larger width. The data of these two experiments, together with the present theoretical analysis, provides a firm evidence of the two pole structure of the Lambda(1405).Comment: 4 pages, 6 figure

Boundary versus bulk behavior of time-dependent correlation functions in one-dimensional quantum systems

We study the influence of reflective boundaries on time-dependent responses of one-dimensional quantum fluids at zero temperature beyond the low-energy approximation. Our analysis is based on an extension of effective mobile impurity models for nonlinear Luttinger liquids to the case of open boundary conditions. For integrable models, we show that boundary autocorrelations oscillate as a function of time with the same frequency as the corresponding bulk autocorrelations. This frequency can be identified as the band edge of elementary excitations. The amplitude of the oscillations decays as a power law with distinct exponents at the boundary and in the bulk, but boundary and bulk exponents are determined by the same coupling constant in the mobile impurity model. For nonintegrable models, we argue that the power-law decay of the oscillations is generic for autocorrelations in the bulk, but turns into an exponential decay at the boundary. Moreover, there is in general a nonuniversal shift of the boundary frequency in comparison with the band edge of bulk excitations. The predictions of our effective field theory are compared with numerical results obtained by time-dependent density matrix renormalization group (tDMRG) for both integrable and nonintegrable critical spin-$S$ chains with $S=1/2$, $1$ and $3/2$.Comment: 20 pages, 12 figure

Working conditions, health and retirement intentions: a case study of truck drivers

Purpose. Being a professional truck driver implies prolonged exposure to physical and psychosocial risks, which can affect health and work ability in the short and long term. The purpose of this paper is to examine the role of working conditions in truck drivers’ perceived health and retirement intentions in a Portuguese transportation company. Design/methodology/approach. Using ergonomic work analysis (EWA), this study incorporates document analysis, observation and 16 interviews. Content analysis is applied to interviews’ transcripts. Findings. In line with previous research, drivers acknowledged their activity as physically demanding (e.g. static postures, repetitive movements, heavy lifting) and psychologically demanding (e.g. high time pressure, lack of control, lack of work–family balance). Despite that, drivers report themselves to be in good health, with only some complaints related to back and knee pain. However, hard working conditions associated with ageing can contribute to gradual health deterioration, leading them to desire to retire before the legal retirement age. Practical implications. The company can promote drivers’ health by creating a unit to provide psychosocial support and career orientation, improving the mentoring programme, and investing in training on occupational risk prevention. Originality/value. This study is the first to use EWA to examine the impact of the complex relationship between truck drivers’ work and health in their retirement intentions, adopting a temporal perspective.info:eu-repo/semantics/acceptedVersio

I-V curves of Fe/MgO (001) single- and double-barrier tunnel junctions

In this work, we calculate with ab initio methods the current-voltage characteristics for ideal single- and double-barrier Fe/MgO (001) magnetic tunnel junctions. The current is calculated in the phase-coherent limit by using the recently developed SMEAGOL code, combining the nonequilibrium Green function formalism with density-functional theory. In general we find that double-barrier junctions display a larger magnetoresistance, which decays with bias at a slower pace than their single-barrier counterparts. This is explained in terms of enhanced spin filtering from the middle Fe layer sandwiched in between the two MgO barriers. In addition, for double-barrier tunnel junctions, we find a well defined peak in the magnetoresistance at a voltage of V=0.1 V. This is the signature of resonant tunneling across a majority quantum well state. Our findings are discussed in relation to recent experiments

Is age just a number? The impact of age-diversity practices and workers' age on health and well-being

Workforces across the world are ageing. Research has been focusing on how Human Resources Management (HRM) can develop and promote sustainable careers for workers of all ages (e.g. Kooij et al., 2013; Schalk et al., 2010; Truxillo, Cadiz, & Hammer, 2015). This study tests two moderation hypotheses: age moderates the effect of perceived age-diversity practices (1) on perceived health and (2) on well-being. Human Resources (HR) practices that consider the needs, goals and preferences of workers of all ages – age-diversity practices – can be a strategy to ensure workers’ well-being and health. Perceived age-diversity practices refer to the degree to which individuals perceive that workers of all ages receive non-discriminatory treatment in terms of organisational practices, policies and procedures (Boehm, Kunze, & Bruch, 2014; Kunze, Boehm, & Bruch, 2013). Organisations can implement these practices to support workers’ health and well-being over time, by adjusting the physical work environment (e.g., ergonomic aspects) and fostering knowledge and skills. Age can have an important role in the impact of perceived age-diversity practices on health and well-being. The assumption is that these practices are especially important for older workers as they are more likely to experience health limitations due to the ageing process (Hansson, DeKoekkoek, Neece, & Patterson, 1997), and they are frequently the target of age discrimination in the workplace (e.g., Finkelstein, Burke, & Raju, 1995; Posthuma & Campion, 2009). A sample of 410 participants aged between 19 and 67 years old (M = 37.74, SD = 12.93) answered to a questionnaire with an on-line and a paper version. The moderation hypotheses were tested by Multiple Linear Regression using PROCESS macro for SPSS (Hayes, 2012). Findings supported the first hypothesis, suggesting that as increases age, also increases the effect of perceived age-diversity practices on perceived health, which means that as age increased, this relationship became more important. The second hypothesis was not supported, because the moderator effect of age was not significant. However, perceived age-diversity practices had a significant main effect on well-being, emphasising the importance of these practices to retain all workers, regardless of their age. These findings suggest that organisations should develop age-diversity practices to improve the well-being of workers of all ages, and that they could be particularly relevant for older workers’ health.info:eu-repo/semantics/acceptedVersio

‘What could make me stay at work’: Retirement transition profiles

Aging populations pose a persistent challenge to the sustainability of public pension systems. To tackle these financial pressures, many countries strengthen the incentives to work by increasing the statutory retirement age and reducing early retirement benefits. These policy reforms make retirement a topic of utmost importance for individuals, organizations, and societies. Although retirement predictors are already a widely studied topic in the literature, there is still much to investigate about why people decide to retire when they do. In particular, the role of work-related variables in the retirement decision-making process is still not fully understood. Thus, the aim of this study was to examine how individual and work factors influence retirement timing (early, on-time, and later retirement). Forty-one interviews were conducted, and data were subjected to content analysis. The inter-relationship between the multiple categories was analyzed by a Multiple Correspondence Analysis (MCA) combined with Cluster Analysis. Results revealed three distinct profiles, which allowed us to group the participants into three clusters. The stay factors profile (e.g., high positive experiences at work, having no dependents, the spouse/partner not being retired) was associated with later retirement. These results can be important for organizations that want and need to retain the best senior talents, by acknowledging that positive experiences at work are associated with older workers’ desire of postponing retirement.info:eu-repo/semantics/acceptedVersio

Age-diversity practices and retirement preferences among older workers: a moderated mediation model of work engagement and work ability

To meet the demographic changes, organizations are challenged to develop practices that retain older workers and encourage them to postpone retirement. The purpose of this paper is to examine the role of human resources (HR) practices in retirement preferences of older workers. Drawing on theories on lifespan development and social exchange, we suggest that organizations can facilitate longer working lives by implementing bundles of HR practices that are sensitive to age-related changes in workers’ skills, preferences, and goals – i.e., age-diversity practices. We posit that age-diversity practices are positively related to work engagement that, in turn, relates to the preference for retiring later. We further suggest that work ability moderates the relationship between age-diversity practices and work engagement. Finally, we propose a moderated mediation model in which the mediated relationship is moderated by work ability. A sample of 232 older Portuguese workers completed a questionnaire. Hypotheses were tested by using structural equation modeling (SEM). Findings show that work engagement completely mediates the relationship between age-diversity practices and the preference for early or late retirement. Moreover, this mediating relationship is more important for those workers who experience low work ability. Results further demonstrate that the effect of age-diversity practices on the preference for retiring later via work engagement is stronger for lower levels of work ability. This study highlights the organizational role in promoting longer and healthier working lives through the implementation of age-supportive HR practices.info:eu-repo/semantics/publishedVersio

Magnetothermal instabilities in magnetized anisotropic plasmas

Using the transport equations for an ideal anisotropic collisionless plasma derived from the Vlasov equation by the 16-moment method, we analyse the influence of pressure anisotropy exhibited by collisionless magnetized plasmas on the magnetothermal (MTI) and heat-flux-driven buoyancy (HBI) instabilities. We calculate the dispersion relation and the growth rates for these instabilities in the presence of a background heat flux and for configurations with static pressure anisotropy, finding that when the frequency at which heat conduction acts is much larger than any other frequency in the system (i.e. weak magnetic field) the pressure anisotropy has no effect on the MTI/HBI, provided the degree of anisotropy is small. In contrast, when this ordering of timescales does not apply the instability criteria depend on pressure anisotropy. Specifically, the growth time of the instabilities in the anisotropic case can be almost one order of magnitude smaller than its isotropic counterpart. We conclude that in plasmas where pressure anisotropy is present the MTI/HBI are modified. However, in environments with low magnetic fields and small anisotropy such as the ICM the results obtained from the 16-moment equations under the approximations considered are similar to those obtained from ideal MHD.Comment: v3: 16 pages, 2 figures, fixed typos, added references and a final note on related wor