The public service-motivated volunteer devoting time or effort: a review and research agenda

The purpose of this conceptual article is to further our understanding of how evolving volunteer trends impact on volunteering intensity. The aim is to provide clarity by applying to the volunteer literature a theoretical framework that can be adapted to different ways in which people volunteer and thus may inform subsequent empirical work. First, we address academic debates concerning the measurement of volunteer effort. Second, we propose using public service motivation (PSM) theory as a means to understand the motivation of volunteers across sectors. We suggest that different PSM dimensions may be more dominant in certain volunteer settings than others and incorporate person–organisation fit as a means to understand the relationship between PSM and volunteering intensity. Finally, this article proposes directions for future research

Does coerced volunteering undermine the public service motivation of volunteers? A moderated mediation model

There has been an the increase within the past 20 years of mandatory volunteering programs within many school systems and in the past year in the UK’s Community Work Placement program. Consequently, there is the potential problem for volunteer coordinators who are managing individuals who have been coerced into volunteering. This coercion may undermine the motivation of volunteers and result in decreased performance. This study addresses the issue by examining the public service motivation (PSM) of 416 volunteers in southwestern UK. We use a moderated mediation model to test if coerced individuals have a poor person-organization fit (P-O fit) and thus a lower level of effort exerted. We found that those individuals who were coerced, but had low levels of PSM reported greater volunteer intensity then their non-coerced volunteers who also had low PSM levels. Whereas, when obligated, it strengthened the relationship between PSM and P-O fit. Consequently, this gives non-profit managers a clearer understanding of how to overcome the challenges coerced volunteers may present

Observation and Spectroscopy of a Two-Electron Wigner Molecule in an Ultra-Clean Carbon Nanotube

Coulomb interactions can have a decisive effect on the ground state of electronic systems. The simplest system in which interactions can play an interesting role is that of two electrons on a string. In the presence of strong interactions the two electrons are predicted to form a Wigner molecule, separating to the ends of the string due to their mutual repulsion. This spatial structure is believed to be clearly imprinted on the energy spectrum, yet to date a direct measurement of such a spectrum in a controllable one-dimensional setting is still missing. Here we use an ultra-clean suspended carbon nanotube to realize this system in a tunable potential. Using tunneling spectroscopy we measure the excitation spectra of two interacting carriers, electrons or holes, and identify seven low-energy states characterized by their spin and isospin quantum numbers. These states fall into two multiplets according to their exchange symmetries. The formation of a strongly-interacting Wigner molecule is evident from the small energy splitting measured between the two multiplets, that is quenched by an order of magnitude compared to the non-interacting value. Our ability to tune the two-electron state in space and to study it for both electrons and holes provides an unambiguous demonstration of the fundamental Wigner molecule state.Comment: SP and FK contributed equally to this wor

CARDIOVASCULAR COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING IN CONGENITAL HEART DISEASE

Cardiac magnetic resonance (CMR) is a non-invasive imaging modality highly reliable for studying cardiovascular morphology and function. Cardiac computed tomography (CCT) can give valuable anatomic information on CHD in children but implies radiation exposure, a relevant issue in children and newborns who are more radiosensitive than adult patients and have a longer lifetime to develop stochastic effects from radiation. We contributed to show the possibility to obtain an impressively low ionizing dose reduction in CHD patients also using standard 64-slice CT scanners. Conversely, CMR holds a pivotal role when functional and flow imaging is required. We showed the role of CMR in evaluating of patients percutaneously implanted with a pulmonary valve. Moreover, we proposed two new approaches for post-processing CMR images, regarding volume estimation of patients with a single ventricle, a rare CHD and a method for quantifying the paradoxical septal motion. CMR and CCT are two fundamental imaging techniques to evaluate patients with complex CHD. Both imaging modalities have limitations and advantages. CMR can evaluate heart function vessel flow but require a long acquisition time and in same patients a long sedation time. CCT has a very high spatial resolution and short acquisition time but implies ionizing radiation exposure. On the one side, we confirming the crucial role of CMR when function analysis is required but also showed the relevant possibilities of x-ray dose reduction in CCT, also using standard 64-slice scanners in the study of CHD patients

Myotonic dystrophy type 1 and high ventricular vulnerability at the electrophysiological evaluation: ICD yes or not?

A significant number of sudden death (SD) is observed in myotonic dystrophy (DM1) despite pacemaker implantation and some consider the ICD to be the preferential device in patients with conduction disease. According to the latest guidelines, prophylactic ICD implantation in patients with neuromuscular disorder should follow the same recommendations of non-ischemic dilated cardiomyopathy, being reasonable when pacing is needed. We here report a case of DM1 patient who underwent ICD implantation even in the absence of conduction disturbances on ECG and ventricular dysfunction/fibrosis at cardiac magnetic resonance. The occurrence of syncope, non-sustained ventricular tachycardias at 24-Holter ECG monitoring and a family history of SD resulted associated with ventricular fibrillation inducibility at electrophysiological study, favouring ICD implantation. On our advice, DM1 patient with this association of SD risk factors should be targeted for ICD implantation

DNS of Turbulent Heat Transfer in Impinging Jets at Different Reynolds and Prandtl Numbers

The heat transfer between an impinging circular jet and a flat plate is studied by means of direct numerical simulations (DNS) for different Prandtl numbers of the fluid. The thermal field is resolved for Pr= 1, 0.72, 0.025, and 0.01. The flow is incompressible and the temperature is treated as a passive scalar field. The jet originates from a fully developed turbulent pipe flow and impinges perpendicularly on a smooth solid heated plate placed at two pipe diameters distance from the jet exit section. The values of Reynolds numbers based on the pipe diameter and bulk mean velocity in the pipe are set to Re= 5300 and Re= 10000. Inflow boundary conditions are enforced using a precursor simulation. Heat transfer at the wall is addressed through the Nusselt number distribution and main flow field statistics. At fixed Reynolds number it is shown that the Prandtl number influences the intensity of the Nusselt number at a given radial location, and that the Nusselt number distribution along the plate exhibit similar features at different Prandtl numbers. The characteristic secondary peak in the Nusselt number distribution is found for both Reynolds numbers for Pr= 0.025 and Pr = 0.01. All the simulations presented in this study were performed with the high order spectral element code Nek5000. Generated flow field statistics are available in the open access repository KITOpen

Signaling response to transient redox stress in human isolated T cells: Molecular sensor role of syk kinase and functional involvement of IL2 receptor and L-selectine

Reactive oxygen species (ROS) are central effectors of inflammation and play a key role in cell signaling. Previous reports have described an association between oxidative events and the modulation of innate immunity. However, the role of redox signaling in adaptive immunity is still not well understood. This work is based on a novel investigation of diamide, a specific oxidant of sulfhydryl groups, and it is the first performed in purified T cell tyrosine phosphorylation signaling. Our data show that ex vivo T cells respond to –SH group oxidation with a distinctive tyrosine phosphorylation response and that these events elicit specific cellular responses. The expression of two essential T-cell receptors, CD25 and CD62L, and T-cell cytokine release is also affected in a specific way. Experiments with Syk inhibitors indicate a major contribution of this kinase in these phenomena. This pilot work confirms the presence of crosstalk between oxidation of cysteine residues and tyrosine phosphorylation changes, resulting in a series of functional events in freshly isolated T cells. Our experiments show a novel role of Syk inhibitors in applying their anti-inflammatory action through the inhibition of a ROS-generated reaction