On the order of a non-abelian representation group of a slim dense near hexagon

We show that, if the representation group $R$ of a slim dense near hexagon $S$ is non-abelian, then $R$ is of exponent 4 and $|R|=2^{\beta}$, $1+NPdim(S)\leq \beta\leq 1+dimV(S)$, where $NPdim(S)$ is the near polygon embedding dimension of $S$ and $dimV(S)$ is the dimension of the universal representation module $V(S)$ of $S$. Further, if $\beta =1+NPdim(S)$, then $R$ is an extraspecial 2-group (Theorem 1.6)

On hyperovals of polar spaces

We derive lower and upper bounds for the size of a hyperoval of a finite polar space of rank 3. We give a computer-free proof for the uniqueness, up to isomorphism, of the hyperoval of size 126 of H(5, 4) and prove that the near hexagon E-3 has up to isomorphism a unique full embedding into the dual polar space DH(5, 4)

The risk linked to ionizing radiation: an alternative epidemiologic approach.

Radioprotection norms have been based on risk models that have evolved over time. These models show relationships between exposure and observed effects. There is a high level of uncertainty regarding lower doses. Recommendations have been based on the conservative hypothesis of a linear relationship without threshold value. This relationship is still debated, and the diverse observations do not allow any definitive conclusion. Available data are contradictory, and various interpretations can be made. Here we review an alternative approach for defining causation and reconciling apparently contradictory conclusions. This alternative epidemiologic approach is based on causal groups: Each component of a causal group is necessary but not sufficient for causality. Many groups may be involved in causality. Thus, ionizing radiation may be a component of one or several causal groups. This formalization reconciles heterogeneous observations but implies searching for the interactions between components, mostly between critical components of a causal profile, and, for instance, the reasons why specific human groups would not show any effect despite exposure, when an effect would be expected

Geometric Hyperplanes of the Near Hexagon L_3 times GQ(2, 2)

Having in mind their potential quantum physical applications, we classify all geometric hyperplanes of the near hexagon that is a direct product of a line of size three and the generalized quadrangle of order two. There are eight different kinds of them, totalling to 1023 = 2^{10} - 1 = |PG(9, 2)|, and they form two distinct families intricately related with the points and lines of the Veldkamp space of the quadrangle in question.Comment: 10 pages, 5 figures and 2 tables; Version 2 - more detailed discussion of the properties of hyperplane

The assessment of efforts to return to work in the European Union

Background: Assessment of efforts to promote return-to-work (RTW) includes all efforts (vocational and non-vocational) designed to improve the work ability of the sick-listed employee and increase the chance to return to work. Aim of the study was to investigate whether in 13 European countries these RTW efforts are assessed and to compare the procedures by means of six criteria. METHODS: Data were gathered in the taxonomy project of the European Union of Medicine in Assurance and Social Security and by means of an additional questionnaire. RESULTS: In seven countries RTW efforts are subject of the assessment in relation to the application for disability benefits. Description of RTW efforts is a prerequisite in five countries. Guidelines on the assessment of RTW efforts are only available in the Netherlands and no countries report the use of the ICF model. Based on the results of the additional questionnaire, the assessor is a social scientist or a physician. The information used to assess RTW efforts differs, from a report on the RTW process to medical information. A negative outcome of the assessment leads to delay of the application for disability benefits or to application for rehabilitation subsidy. Conclusion: RTW efforts are assessed in half of the participating European countries. When compared, the characteristics of the assessment of RTW efforts in the participating European countries show both similarities and differences. This study may facilitate the gathering and exchange of knowledge and experience between countries on the assessment of RTW efforts

Local Shearing Force Measurement during Frictional Sliding Using Fluorogenic Mechanophores

[Image: see text] When two macroscopic objects touch, the real contact typically consists of multiple surface asperities that are deformed under the pressure that holds the objects together. Application of a shear force makes the objects slide along each other, breaking the initial contacts. To investigate how the microscopic shear force at the asperity level evolves during the transition from static to dynamic friction, we apply a fluorogenic mechanophore to visualize and quantify the local interfacial shear force. When a contact is broken, the shear force is released and the molecules return to their dark state, allowing us to dynamically observe the evolution of the shear force at the sliding contacts. We find that the macroscopic coefficient of friction describes the microscopic friction well, and that slip propagates from the edge toward the center of the macroscopic contact area before sliding occurs. This allows for a local understanding of how surfaces start to slide

Effect of inelastic scattering on parametric pumping

Pumping of charge in phase-coherent mesoscopic systems due to the out-of-phase modulation of two parameters has recently found considerable interest. We investigate the effect of inelastic processes on the adiabatically pumped current through a two terminal mesoscopic sample. We find that the loss of coherence does not suppress the pumped charge but rather an additional physical mechanism for an incoherent pump effect comes into play. In a fully phase incoherent system the pump effect is similar to a rectification effect

Staying at work with chronic nonspecific musculoskeletal pain:a qualitative study of workers' experiences

BACKGROUND: Many people with chronic nonspecific musculoskeletal pain (CMP) have decreased work ability. The majority, however, stays at work despite their pain. Knowledge about workers who stay at work despite chronic pain is limited, narrowing our views on work participation. The aim of this study was to explore why people with CMP stay at work despite pain (motivators) and how they manage to maintain working (success factors). METHODS: A semi-structured interview was conducted among 21 subjects who stay at work despite CMP. Participants were included through purposeful sampling. Interviews were audio-recorded, transcribed verbatim, and imported into computer software Atlas.ti. Data was analyzed by means of thematic analysis. The interviews consisted of open questions such as: "Why are you working with pain?" or "How do you manage working while having pain?" RESULTS: A total of 16 motivators and 52 success factors emerged in the interviews. Motivators were categorized into four themes: work as value, work as therapy, work as income generator, and work as responsibility. Success factors were categorized into five themes: personal characteristics, adjustment latitude, coping with pain, use of healthcare services, and pain beliefs. CONCLUSIONS: Personal characteristics, well-developed self-management skills, and motivation to work may be considered to be important success factors and prerequisites for staying at work, resulting in behaviors promoting staying at work such as: raising adjustment latitude, changing pain-coping strategies, organizing modifications and conditions at work, finding access to healthcare services, and asking for support. Motivators and success factors for staying at work may be used for interventions in rehabilitation and occupational medicine, to prevent absenteeism, or to promote a sustainable return to work. This qualitative study has evoked new hypotheses about staying at work; quantitative studies on staying at work are needed to obtain further evidence