Collective polarization exchanges in collisions of photon clouds

The one-loop "vacuum" Heisenberg-Euler coupling of four electromagnetic fields can lead to interesting collective effects in the collision of two photon clouds, on a time scale orders of magnitude faster than one estimates from the cross-section and density. We estimate the characteristic time for macroscopic transformation of positive to negative helicity in clouds that are initially totally polarized and for depolarization of a polarized beam traversing an unpolarized cloud.Comment: Recapitulates much that is in hep-ph/0402127, with new results in the last section, and the first section drastically reduced in view of the previous work of Kotkin and Serbo. Typo corrected in eq. 1

Tailored support for preparing employees with cancer to work:Recognition and gaining new insights in an open atmosphere

BackgroundA considerable number of cancer survivors face difficulties in returning to work (RTW). More insight is needed on how to support employees shortly after cancer treatment and help them make the transition back to work.ObjectiveTo gain an in-depth understanding of how and under what circumstances a Cancer & Work Support (CWS) program, which assists sick-listed employees with cancer in preparing their RTW, works.MethodsA qualitative design was used, inspired by Grounded Theory and Realist Evaluation components. Semi-structured interviews were conducted with RTW professionals (N = 8) and employees with cancer (N = 14). Interview themes covered experiences with CWS, active elements, and impeding and facilitating factors. Interviews were transcribed and analyzed by multiple researchers for contextual factors, active mechanisms, and the outcomes experienced.ResultsRespondents experienced the support as human centered, identifying two characteristics: 'Involvement' ('how' the support was offered), and 'Approach' ('what' was offered). Four themes were perceived as important active elements: 1) open connection and communication, 2) recognition and attention, 3) guiding awareness and reflection, and 4) providing strategies for coping with the situation. Variation in the experiences and RTW outcomes, appeared to be related to the personal, medical and environmental context.ConclusionBoth professionals and employees really appreciated the CWS because it contributed to RTW after cancer. This research shows that not only 'what' RTW professionals do, but also 'how' they do it, is important for meaningful RTW support. A good relationship in an open and understanding atmosphere can contribute to the receptiveness (of employees) for cancer support

Some remarks on the spectral functions of the Abelian Higgs Model

We consider the unitary Abelian Higgs model and investigate its spectral functions at one-loop order. This analysis allows to disentangle what is physical and what is not at the level of the elementary particle propagators, in conjunction with the Nielsen identities. We highlight the role of the tadpole graphs and the gauge choices to get sensible results. We also introduce an Abelian Curci-Ferrari action coupled to a scalar field to model a massive photon which, like the non-Abelian Curci-Ferarri model, is left invariant by a modified non-nilpotent BRST symmetry. We clearly illustrate its non-unitary nature directly from the spectral function viewpoint. This provides a functional analogue of the Ojima observation in the canonical formalism: there are ghost states with nonzero norm in the BRST-invariant states of the Curci-Ferrari model.Comment: 32 pages, 12 figure

Trends en scenarios's voor de natuurverkenning 2

Waar heeft het natuurbeleid de komende jaren rekening mee te houden? Diverse auteurs analyseren verwachte trends in verstedelijking, landbouw en bestuur en gaan na welke trends een positief effect kunnen hebben op natuur en landschap

Revisions of Extensive Acetabular Defects with Impaction Grafting and a Cement Cup

Item does not contain fulltextBACKGROUND: Loosening of acetabular components often leads to bony defects. Management of extensive acetabular bone loss in hip revision arthroplasty can be a tremendous challenge. QUESTIONS/PURPOSES: We asked whether a reconstruction with impacted bone grafts will provide a durable and pain-free function in extensive acetabular defects. We specifically determined the (1) survival rates with the end point of revision for any reason, aseptic revision, and radiographic loosening; (2) visual analog scale (VAS) pain score, Harris hip score (HHS), and the Oxford Hip Questionnaire score (OHQS); (3) number of repeat revisions; (4) complications; and (5) radiographic loosening, wear, and radiolucencies. PATIENTS AND METHODS: We retrospectively followed 25 patients (27 hips) with extensive acetabular defects. No patient was lost to followup. Two patients died during followup. Minimum followup was 3 years (mean, 8.8 years; range, 3-14.1 years). RESULTS: Three patients (three hips) underwent repeat revision surgery and another two patients (two hips) had radiographically loose hips. The 10-year survival rate was 88% (95% confidence interval, 74.2%-100%) with the end point acetabular revision for any reason and 95% (95% confidence interval, 86.0%-100%) with the end point acetabular revision for aseptic loosening. The mean HHSs were 55 points before surgery and 72 points postoperatively. CONCLUSIONS: Acetabular reconstruction with impaction bone grafting and a cemented cup is a reliable technique with a 10-year survival rate of 88% in patients with extensive acetabular deficiencies. LEVEL OF EVIDENCE: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence

Body composition is associated with tacrolimus pharmacokinetics in kidney transplant recipients

PURPOSE: A population pharmacokinetic (popPK) model may be used to improve tacrolimus dosing and minimize under- and overexposure in kidney transplant recipients. It is unknown how body composition parameters relate to tacrolimus pharmacokinetics and which parameter correlates best with tacrolimus exposure. The aims of this study were to investigate which body composition parameter has the best association with the pharmacokinetics of tacrolimus and to describe this relationship in a popPK model. METHODS: Body composition was assessed using bio-impedance spectroscopy (BIS). Pharmacokinetic analysis was performed using nonlinear mixed effects modeling (NONMEM). Lean tissue mass, adipose tissue mass, over-hydration, and phase angle were measured with BIS and then evaluated as covariates. The final popPK model was evaluated using goodness-of-fit plots, visual predictive checks, and a bootstrap analysis. RESULTS: In 46 kidney transplant recipients, 284 tacrolimus concentrations were measured. The base model without body composition parameters included age, plasma albumin, plasma creatinine, CYP3A4 and CYP3A5 genotypes, and hematocrit as covariates. After full forward inclusion and backward elimination, only the effect of the phase angle on clearance (dOFV =  − 13.406; p < 0.01) was included in the final model. Phase angle was positively correlated with tacrolimus clearance. The inter-individual variability decreased from 41.7% in the base model to 34.2% in the final model. The model was successfully validated. CONCLUSION: The phase angle is the bio-impedance spectroscopic parameter that correlates best with tacrolimus pharmacokinetics. Incorporation of the phase angle in a popPK model can improve the prediction of an individual’s tacrolimus dose requirement after transplantation. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00228-022-03323-0

Are we on the right track in DBS surgery for dystonic head tremor?:Polymyography is a promising answer

The clinical benefit of Deep Brain Stimulation (DBS) is associated with electrode positioning accuracy. Intraoperative assessment of clinical effect is therefore key. Evaluating this clinical effect in patients with dystonic head tremor, as opposed to limb tremor, is challenging because the head is fixed in a stereotactic frame. To clinically assess head tremor during surgery, surface electromyography (EMG) electrodes were bilaterally applied to the sternocleidomastoid and cervical paraspinal muscles. This case shows that intraoperative polymyography is an easy and useful tool to assess the clinical effect of DBS electrode positioning