1,189 research outputs found
Behavioral determinants as predictors of return to work after long-term sickness absence: an application of the theory of planned behavior
Background The aim of this prospective, longitudinal cohort study was to analyze the association between the three behavioral determinants of the theory of planned behavior (TPB) model-attitude, subjective norm and self-efficacy-and the time to return-to-work (RTW) in employees on long-term sick leave. Methods The study was based on a sample of 926 employees on sickness absence (maximum duration of 12 weeks). The employees filled out a baseline questionnaire and were subsequently followed until the tenth month after listing sick. The TPB-determinants were measured at baseline. Work attitude was measured with a Dutch language version of the Work Involvement Scale. Subjective norm was measured with a self-structured scale reflecting a person's perception of social support and social pressure. Self-efficacy was measured with the three subscales of a standardised Dutch version of the general self-efficacy scale (ALCOS): willingness to expend effort in completing the behavior, persistence in the face of adversity, and willingness to initiate behavior. Cox proportional hazards regression analyses were used to identify behavioral determinants of the time to RTW. Results Median time to RTW was 160 days. In the univariate analysis, all potential prognostic factors were significantly associated (P < 0.15) with time to RTW: work attitude, social support, and the three subscales of self-efficacy. The final multivariate model with time to RTW as the predicted outcome included work attitude, social support and willingness to expend effort in completing the behavior as significant predictive factors. Conclusions This prospective, longitudinal cohort-study showed that work attitude, social support and willingness to expend effort in completing the behavior are significantly associated with a shorter time to RTW in employees on long-term sickness absence. This provides suggestive evidence for the relevance of behavioral characteristics in the prediction of duration of sickness absence. It may be a promising approach to address the behavioral determinants in the development of interventions focusing on RTW in employees on long-term sick leave
Development of Iron Speciation Reference Materials for Palaeoredox Analysis
The development and application of geochemical techniques to identify redox conditions in modern and ancient aquatic environments has intensified over recent years. Iron (Fe) speciation has emerged as one of the most widely used procedures to distinguish different redox regimes in both the water column and sediments, and is the main technique used to identify oxic, ferruginous (anoxic, Fe(II) containing) and euxinic (anoxic, sulfidic) water column conditions. However, an international sediment reference material has never been developed. This has led to concern over the consistency of results published by the many laboratories that now utilise the technique. Here, we report an interlaboratory comparison of four Fe speciation reference materials for palaeoredox analysis, which span a range of compositions and reflect deposition under different redox conditions. We provide an update of extraction techniques used in Fe speciation, and assess the effects of both test portion mass, and the use of different analytical procedures, on the quantification of different Fe fractions in sedimentary rocks. While atomic adsorption spectroscopy and inductively coupled plasma‐optical emission spectrometry produced comparable Fe measurements for all extraction stages, the use of ferrozine consistently underestimated Fe in the extraction step targeting mixed ferrous‐ferric minerals such as magnetite. We therefore suggest that the use of ferrozine is discontinued for this Fe pool. Finally, we report the combined data of four independent Fe speciation laboratories to characterise the Fe speciation composition of the reference materials. These reference materials are available to the community to provide an essential validation of in‐house Fe speciation measurements
Group formation under limited resources: narrow basin of equality
The formation of groups in competition and the aggressive interactions between them are ubiquitous phenomena in society. These include student activities in the classroom, election races between political parties, and intensifying trade wars between countries. Why do individuals form themselves into groups? What is the optimal size of groups? And how does the group size distribution affect resource allocations? These questions have been the subjects of intense research in economics, political science, sociology, and ethology. In this study, we explore the group-size effects on the formation of groups and resource allocations from an economic standpoint. While being in a large group is generally advantageous in competition, an increase in the management costs would set an upper bound to the individual benefit of members. Under such counteracting size effects, we consider the dynamics of group formation in which people seek a conservative measure to reduce their possible maximum loss. We are especially interested in the effects of group size on social inequalities at both group and individual level in resource allocation. Our findings show that the low positive size-effect and the high negative size-effect result in different types of social inequalities. We conclude, from the relation between the inequality measures and group distributions predicted within the model, that overall social equality only can be achieved within a narrow region where two counteracting size-effects are balanced
Oil spill response capabilities and technologies for ice-covered Arctic marine waters: A review of recent developments and established practices
Renewed political and commercial interest in the resources of the Arctic, the reduction in the extent and thickness of sea ice, and the recent failings that led to the Deepwater Horizon oil spill, have prompted industry and its regulatory agencies, governments, local communities and NGOs to look at all aspects of Arctic oil spill countermeasures with fresh eyes. This paper provides an overview of present oil spill response capabilities and technologies for ice-covered waters, as well as under potential future conditions driven by a changing climate. Though not an exhaustive review, we provide the key research results for oil spill response from knowledge accumulated over many decades, including significant review papers that have been prepared as well as results from recent laboratory tests, field programmes and modelling work. The three main areas covered by the review are as follows: oil weathering and modelling; oil detection and monitoring; and oil spill response techniques
Examination and measurement of coping among adolescents with spinal cord injury
Objectives:
To describe coping strategy use in adolescents with spinal cord injury (SCI), to explore the underlying factor structure of a measure of coping among adolescents with SCI and to assess relationships between coping and psychosocial outcomes. Setting: Multiple pediatric SCI centers in the United States.
Methods:
One hundred and eighty-two participants aged 13–17 years who experienced an SCI completed measures including the Kidcope, Children’s Depression Inventory, Revised Children’s Manifest Anxiety Scale and the Pediatric Quality of Life Inventory.
Results:
Participants reported that cognitive restructuring and resignation are the most used coping strategies, whereas social support, emotional regulation (calming) and cognitive restructuring are the most effective coping strategies. An exploratory factor analysis revealed that a three-factor solution provided the most parsimonious model for the relationships between the different coping strategies. However, only one of the three factors had acceptable internal consistency. This factor comprised escape-oriented coping strategies or an avoidant approach to coping with the sequelae of SCI. After controlling for demographic/injury-related factors, higher scores on the escape-oriented factor were associated with the lower quality of life and higher levels of depression and anxiety symptomatology.
Conclusion:
Escape-oriented coping is associated with maladaptive psychosocial outcomes in adolescents with SCI. These adolescents report that active coping strategies are most effective in reducing SCI-related distress. Coping strategy use may mediate psychosocial outcomes in adolescents with SCI and represent an intervention target in adolescents who overly rely on escape-oriented coping
Preparation, structural characterisation and antibacterial properties of Ga-doped sol-gel phosphate-based glass
A sol-gel preparation of Ga-doped phosphate-based glass with potential application in antimicrobial devices has been developed. Samples of composition (CaO)(0.30)(Na2O)(0.20-x) (Ga2O3) (x) (P2O5)(0.50) where x = 0 and 0.03 were prepared, and the structure and properties of the gallium-doped sample compared with those of the sample containing no gallium. Analysis of the P-31 MAS NMR data demonstrated that addition of gallium to the sol-gel reaction increases the connectivity of the phosphate network at the expense of hydroxyl groups. This premise is supported by the results of the elemental analysis, which showed that the gallium-free sample contains significantly more hydrogen and by FTIR spectroscopy, which revealed a higher concentration of -OH groups in that sample. Ga K-edge extended X-ray absorption fine structure and X-ray absorption near-edge structure data revealed that the gallium ions are coordinated by six oxygen atoms. In agreement with the X-ray absorption data, the high-energy XRD results also suggest that the Ga3+ ions are octahedrally coordinated with respect to oxygen. Antimicrobial studies demonstrated that the sample containing Ga3+ ions had significant activity against Staphylococcus aureus compared to the control
Happy Protest Voters: The Case of Rotterdam 1997–2009
Protest parties are on the rise in several European countries. This development is commonly attributed to a growing dissatisfaction with life and associated with declining quality of life in modern society of the lowest social strata. This explanation is tested in a cross-sectional analysis of voting and life-satisfaction in 63 districts of the city of Rotterdam in the Netherlands, where the share of protest voters increased from 10 % in 1994 to 31 % in 2009. Contrary to this explanation protest voting appeared not to be the most frequent in the least happy districts of Rotterdam, but in the medium happy segment. Also divergent from this explanation was that average happiness in city districts is largely independent of local living conditions, but is rather a matter of personal vulnerability in terms of education, income and health. These results fit alternative explanations in terms of mid
Understanding Animal Group-Size Distributions
One of the most striking aspects of animal groups is their remarkable variation in size, both within and between species. While a number of mechanistic models have been proposed to explain this variation, there are few comprehensive datasets against which these models have been tested. In particular, we only vaguely understand how environmental factors and behavioral activities affect group-size distributions. Here we use observations of House sparrows (Passer domesticus) to investigate the factors determining group-size distribution. Over a wide range of conditions, we observed that animal group sizes followed a single parameter distribution known as the logarithmic distribution. This single parameter is the mean group size experienced by a randomly chosen individual (including the individual itself). For sparrows, the experienced mean group size, and hence the distribution, was affected by four factors: morning temperature, place, behavior and the degree of food spillage. Our results further indicate that the sparrows regulate the mean group size they experience, either by groups splitting more or merging less when local densities are high. We suggest that the mean experienced group size provides a simple but general tool for assessing the ecology and evolution of grouping
Spin dynamics of molecular nanomagnets fully unraveled by four-dimensional inelastic neutron scattering
Molecular nanomagnets are among the first examples of spin systems of finite
size and have been test-beds for addressing a range of elusive but important
phenomena in quantum dynamics. In fact, for short-enough timescales the spin
wavefunctions evolve coherently according to the an appropriate cluster
spin-Hamiltonian, whose structure can be tailored at the synthetic level to
meet specific requirements. Unfortunately, to this point it has been impossible
to determine the spin dynamics directly. If the molecule is sufficiently
simple, the spin motion can be indirectly assessed by an approximate model
Hamiltonian fitted to experimental measurements of various types. Here we show
that recently-developed instrumentation yields the four-dimensional
inelastic-neutron scattering function S(Q,E) in vast portions of reciprocal
space and enables the spin dynamics to be determined with no need of any model
Hamiltonian. We exploit the Cr8 antiferromagnetic ring as a benchmark to
demonstrate the potential of this new approach. For the first time we extract a
model-free picture of the quantum dynamics of a molecular nanomagnet. This
allows us, for example, to examine how a quantum fluctuation propagates along
the ring and to directly test the degree of validity of the
N\'{e}el-vector-tunneling description of the spin dynamics
Mesoscopic organization reveals the constraints governing C. elegans nervous system
One of the biggest challenges in biology is to understand how activity at the
cellular level of neurons, as a result of their mutual interactions, leads to
the observed behavior of an organism responding to a variety of environmental
stimuli. Investigating the intermediate or mesoscopic level of organization in
the nervous system is a vital step towards understanding how the integration of
micro-level dynamics results in macro-level functioning. In this paper, we have
considered the somatic nervous system of the nematode Caenorhabditis elegans,
for which the entire neuronal connectivity diagram is known. We focus on the
organization of the system into modules, i.e., neuronal groups having
relatively higher connection density compared to that of the overall network.
We show that this mesoscopic feature cannot be explained exclusively in terms
of considerations, such as optimizing for resource constraints (viz., total
wiring cost) and communication efficiency (i.e., network path length).
Comparison with other complex networks designed for efficient transport (of
signals or resources) implies that neuronal networks form a distinct class.
This suggests that the principal function of the network, viz., processing of
sensory information resulting in appropriate motor response, may be playing a
vital role in determining the connection topology. Using modular spectral
analysis, we make explicit the intimate relation between function and structure
in the nervous system. This is further brought out by identifying functionally
critical neurons purely on the basis of patterns of intra- and inter-modular
connections. Our study reveals how the design of the nervous system reflects
several constraints, including its key functional role as a processor of
information.Comment: Published version, Minor modifications, 16 pages, 9 figure
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