Plasmons and screening in a monolayer of MoS2_2

We investigate the dynamical dielectric function of a monolayer of molybdenum disulfide within the random phase approximation. While in graphene damping of plasmons is caused by interband transitions, due to the large direct band gap in monolayer MoS$_2$ collective charge excitations enter the intraband electron hole continuum similar to the situation in two-dimensional electron and hole gases. Since there is no electron-hole symmetry in MoS$_2$, the plasmon energies in p- and n-doped samples clearly differ. The breaking of spin degeneracy caused by the large intrinsic spin-orbit interaction leads to a beating of Friedel oscillations for sufficiently large carrier concentrations, for holes as well as for electrons.Comment: 7 pages, 8 figures; typos correcte

De-standardised pathways to adulthood : european perspectives on informal learning in informal networks

Becoming adult in the context of de-standardised life course transitions means new demands for the young women and men concerned. While those with higher social and cultural capital cope more easily with shaping individualised transitions, those with restricted resources and opportunities are under pressure of adaptation and at risk of exclusion. While de-standardisation can be regarded as a general trend, it takes varying shape across different European transition regimes whereby different regulative, normative and policy contexts of youth transitions are clustered. The article relates to the European YOYO study which has explored new learning demands and new learning strategies of young people in a comparative perspective. An exemplary illustration refers to the way in which young Germans make use of informal learning networks to cope with these demands. This micro perspective is related to the macro perspective by reflecting the scopes of individual agency provided by different transition regimes.Esdevenir adult en el context de les transicions desestandarditzades de la vida comporta noves demandes per part dels joves, els homes i les dones afectats. Mentre que aquells que disposen d'un capital social i cultural més elevat poden modelar més fàcilment les transicions individualitzades, aquells que no disposen de tants recursos ni oportunitats es troben sota la pressió d'adaptar-se i davant el perill de l'exclusió. Si bé la desestandardització es pot veure com una tendència general, adopta diferents formes en els diferents règims de transició europeus a través dels quals s'agrupen diferents contextos regulatius, normatius i polítics de les transicions juvenils. L'article està relacionat amb l'estudi europeu YOYO, que ha explorat noves demandes d'ensenyament i noves estratègies d'ensenyament dels joves des d'un punt de vista comparatiu. Un exemple il·lustratiu fa referència a com els joves alemanys utilitzen xarxes d'aprenentatge informals per poder fer front a aquestes demandes. Aquesta microperspectiva està relacionada amb la macro perspectiva, ja que reflecteix l'abast de l'agència individual que proporcionen els diferents règims de transició

How to avoid cooling out? Experiences of young people in their transitions to work across Europe

In this working paper the authors investigate the active engagement of young women and men in shaping their transitions from school to work. How do they navigate through increasingly flexible and risk-laden transition systems? What strategies do they apply to develop and maintain learning motivation or to cope with de-motivation? The research was conducted with funding from the EUs Fifth Framework Programme and involves research teams from Denmark, East and West Germany, Great Britain (Northern Ireland), Ireland (Republic), Italy, the Netherlands, Portugal, Romania and Spain. Under the title "Youth Policy and Participation. Potentials of Participation and Informal Learning for Young People\u27s Transitions to the Labour Market" it investigates how young people use programmes and training measures which define active participation and the involvement of participants as essential for their approach towards young people. (Author)In diesem Arbeitspapier untersuchen die AutorInnen das aktive Engagement junger Frauen und Männer in der Gestaltung ihrer Übergänge von der Schule in den Beruf. Wie navigieren sie durch zunehmen flexibilisierte und risikobehaftete Übergangssysteme? Welche Strategien wenden sie an, um Lernmotivation zu entwickeln und aufrechtzuerhalten? Und wie gehen sie mit demotivierenden Erfahrungen um? Das zugrundeliegende Forschungsprojekt wurde finanziert mit Mitteln aus dem 5. Rahmenforschungsprogramm der EU. Beteiligt waren Forschungsteams aus Dänemark, Deutschland (Ost und West), Großbritannien (Nordirland), Irland, Italien, den Niederlanden, Portugal, Rumänien und Spanien. Unter dem Titel "Jugendpolitik und Partizipation. Potenziale von Partizipation und informellem Lernen für die Übergänge junger Menschen in den Arbeitsmarkt" untersucht das Projekt, wie Jugendliche und junge Erwachsene Unterstützungs- und Trainingsmaßnahmen nutzen, die aktive Beteiligung und Mitbestimmung der TeilnehmerInnen zum zentralen Bestandteil ihres Arbeitskonzeptes machen. (Autor

A Convenient Route to Monoalkyl-Substituted Phosphanylboranes (HRP–BH2–NMe3): Prospective Precursors to Poly[(alkylphosphino)boranes]

A simple method to access borylphosphonium iodides [RH2P-BH2 center dot NMe3]I (1a: R = Me; 1b: R = Et; 1c: R = nPr) by the addition of iodoalkanes to PH2-BH2 center dot NMe3 was developed. Complexes 1a-c were characterized by multinuclear NMR spectroscopy, and 1a and 1b additionally by single-crystal X-ray diffraction. It was possible to synthesize the Lewis-base-stabilized organosubstituted phosphanylborane MePH-BH2 center dot NMe3 (2) from [MePH2-BH2 center dot NMe3] I (1a). Thermolysis of 2 generated a soluble, low-molecular-mass poly(alkylphosphinoborane)consisting of at least 40 repeat units, as identified by ESI-MS. These results are promising for the future preparation of a wide range of Lewis-base-stabilized phosphanylboranes, which are of interest as precursors to poly[(alkylphosphino)boranes] and are otherwise difficult to access by conventional metal-catalyzed methods

Impact of single versus double transseptal puncture on outcome and complications in pulmonary vein isolation procedures

Background: The aim of the current study was to analyze the impact of single versus double transseptal puncture (TSP) for atrial fibrillation (AF) ablation.Methods: Consecutive patients undergoing AF ablation were prospectively included in the AF ablation registry and were analyzed according to single versus double TSP.Results: A total of 478 patients (female 35%, persistent AF 67%) undergoing AF ablation between 01/2014 and 09/2014 were included. Single TSP was performed in 202 (42%) patients, double TSP in 276 (58%) patients. Age, gender, body mass index, CHA2DS2-VASc score, left ventricular ejection fraction and operator experience (experienced operator defined as ≥ 5 years of experience in invasive electrophysiology) were equally distributed between the two groups. Repeat procedures (re-dos) were more frequently performed using single TSP access (p < 0.001). Left atrial (LA) diameter was larger in patients with double TSP (p = 0.001). Procedure duration in single TSP was identical to double TSP procedures (p = 0.823). Radiation duration was similar between the two groups (p = 0.217). There were 49 (10%) patients with complications after catheter ablation. There were no differences between complication rates and TSP type (p = 0.555). Similarly, recurrence rates were comparable between both TSP groups (p = 0.788).Conclusions: There was no clear benefit of single or double TSP in AF ablation

Physical activity and brain health in patients with atrial fibrillation

Background and purpose: Vascular brain lesions, such as ischemic infarcts, are common among patients with atrial fibrillation (AF) and are associated with impaired cognitive function. The role of physical activity (PA) in the prevalence of brain lesions and cognition in AF has not been investigated. Methods: Patients from the multicenter Swiss‐AF cohort study were included in this cross‐sectional analysis. We assessed regular exercise (RE; at least once weekly) and minutes of weekly PA using a validated questionnaire. We studied associations with ischemic infarcts, white matter hyperintensities, cerebral microbleeds, and brain volume on brain magnetic resonance imaging and with global cognition measured with a cognitive construct (CoCo) score.ResultsAmong 1490 participants (mean age = 72 ± 9 years), 730 (49%) engaged in RE. In adjusted regression analyses, RE was associated with a lower prevalence of ischemic infarcts (odds ratio [OR] = 0.78, 95% confidence interval [CI] = 0.63–0.98, p = 0.03) and of moderate to severe white matter hyperintensities (OR = 0.78, 95% CI = 0.62–0.99, p = 0.04), higher brain volume (β‐coefficient = 10.73, 95% CI = 2.37–19.09, p = 0.01), and higher CoCo score (β‐coefficient = 0.08, 95% CI = 0.03–0.12, p < 0.001). Increasing weekly PA was associated with higher brain volume (β‐coefficient = 1.40, 95% CI = 0.65–2.15, p < 0.001). Conclusions: In AF patients, RE was associated with a lower prevalence of ischemic infarcts and of moderate to severe white matter disease, with larger brain volume, and with better cognitive performance. Prospective studies are needed to investigate whether these associations are causal. Until then, our findings suggest that patients with AF should be encouraged to remain physically active

Mid-term changes in cognitive functions in patients with atrial fibrillation: a longitudinal analysis of the Swiss-AF cohort

Background: Longitudinal association studies of atrial fibrillation (AF) and cognitive functions have shown an unclear role of AF-type and often differ in methodological aspects. We therefore aim to investigate longitudinal changes in cognitive functions in association with AF-type (non-paroxysmal vs. paroxysmal) and comorbidities in the Swiss-AF cohort. Methods: Seven cognitive measures were administered up to five times between 2014 and 2022. Age-education standardized scores were calculated and association between longitudinal change in scores and baseline AF-type investigated using linear mixed-effects models. Associations between AF-type and time to cognitive drop, an observed score of at least one standard deviation below individual's age-education standardized cognitive scores at baseline, were studied using Cox proportional hazard models of each cognitive test, censoring patients at their last measurement. Models were adjusted for baseline covariates.Results2,415 AF patients (mean age 73.2 years; 1,080 paroxysmal, 1,335 non-paroxysmal AF) participated in this Swiss multicenter prospective cohort study. Mean cognitive scores increased longitudinally (median follow-up 3.97 years). Non-paroxysmal AF patients showed smaller longitudinal increases in Digit Symbol Substitution Test (DSST), Cognitive Construct Score (CoCo)and Trail Making Test part B (TMT-B) scores vs. paroxysmal AF patients. Diabetes, history of stroke/TIA and depression were associated with worse performance on all cognitive tests. No differences in time to cognitive drop were observed between AF-types in any cognitive test. Conclusion: This study indicated preserved cognitive functioning in AF patients, best explained by practice effects. Smaller practice effects were found in non-paroxysmal AF patients in the DSST, TMT-B and the CoCo and could indicate a marker of subtle cognitive decline. As diabetes, history of stroke/TIA and depression—but not AF-type—were associated with cognitive drop, more attention should be given to risk factors and underlying mechanisms of AF

Mid-term changes in cognitive functions in patients with atrial fibrillation: a longitudinal analysis of the Swiss-AF cohort.

BACKGROUND Longitudinal association studies of atrial fibrillation (AF) and cognitive functions have shown an unclear role of AF-type and often differ in methodological aspects. We therefore aim to investigate longitudinal changes in cognitive functions in association with AF-type (non-paroxysmal vs. paroxysmal) and comorbidities in the Swiss-AF cohort. METHODS Seven cognitive measures were administered up to five times between 2014 and 2022. Age-education standardized scores were calculated and association between longitudinal change in scores and baseline AF-type investigated using linear mixed-effects models. Associations between AF-type and time to cognitive drop, an observed score of at least one standard deviation below individual's age-education standardized cognitive scores at baseline, were studied using Cox proportional hazard models of each cognitive test, censoring patients at their last measurement. Models were adjusted for baseline covariates. RESULTS 2,415 AF patients (mean age 73.2 years; 1,080 paroxysmal, 1,335 non-paroxysmal AF) participated in this Swiss multicenter prospective cohort study. Mean cognitive scores increased longitudinally (median follow-up 3.97 years). Non-paroxysmal AF patients showed smaller longitudinal increases in Digit Symbol Substitution Test (DSST), Cognitive Construct Score (CoCo)and Trail Making Test part B (TMT-B) scores vs. paroxysmal AF patients. Diabetes, history of stroke/TIA and depression were associated with worse performance on all cognitive tests. No differences in time to cognitive drop were observed between AF-types in any cognitive test. CONCLUSION This study indicated preserved cognitive functioning in AF patients, best explained by practice effects. Smaller practice effects were found in non-paroxysmal AF patients in the DSST, TMT-B and the CoCo and could indicate a marker of subtle cognitive decline. As diabetes, history of stroke/TIA and depression-but not AF-type-were associated with cognitive drop, more attention should be given to risk factors and underlying mechanisms of AF

Examination of Indium Triphospholyls as Precursors for Nanoparticle Synthesis

The synthesis and characterization of the new compounds K(P3C2R2) [R=Ad (2), sBu (3)] and In(P3C2R2) [R=Ad (4), Mes (5)] are described. Further, the synthesis of indium nanoparticles via a single‐source precursor approach using In(1,2,4‐P3C2tBu2) (1) as precursor is reported. These nanoparticles were characterized by TEM, HRTEM, EDX, XRD, NMR, and optical spectroscopy. New compounds of the type M(1,2,4‐P3C2R2) (M=K, In, R=Ad, sBu, Mes) were synthesized, characterized, and examined in view of their use as precursors for indium‐based nanoparticles

Increased dose efficiency of breast CT with grating interferometry

Refraction-based x-ray imaging can overcome the fundamental contrast limit of computed tomography (CT), particularly in soft tissue, but so far has been constrained to high-dose ex vivo applications or required highly coherent x-ray sources, such as synchrotrons. Here we demonstrate that grating interferometry (GI) is more dose efficient than conventional CT in imaging of human breast under close-to-clinical conditions. Our system, based on a conventional source and commercial gratings, outperformed conventional CT for spatial resolutions better than 263 µm and absorbed dose of 16 mGy. The sensitivity of GI is constrained by grating fabrication, and further progress will lead to significant improvements of clinical CT