Probing spin dynamics and quantum relaxation in LiY0.998Ho0.002F4 via 19F NMR

We report measurements of 19F nuclear spin-lattice relaxation 1/T1 as a function of temperature and external magnetic field in LiY0.998Ho0.002F4 single crystal, a single-ion magnet exhibiting interesting quantum effects. The 19F 1/T1 is found to depend on the coupling with the diluted rare-earth (RE) moments. Depending on the temperature range, a fast spin diffusion regime or a diffusion limited regime is encountered. In both cases we find it possible to use the 19F nucleus as a probe of the rare-earth spin dynamics. The results for 1/T1 show a behavior similar to that observed in molecular nanomagnets, a result which we attribute to the discreteness of the energy levels in both cases. At intermediate temperatures the lifetime broadening of the crystal field split RE magnetic levels follows a T3 power law. At low temperature the field dependence of 1/T1 shows peaks in correspondence to the critical magnetic fields for energy level crossings (LC). The results can be explained by inelastic scattering between the fluorine nuclear spins and the RE magnetic levels. A key result of this study is that the broadening of the levels at LC is found to be become extremely small at low temperatures, about 1.7 mT, a value which is comparable to the weak dipolar fields at the RE lattice positions. Thus, unlike the molecular magnets, decoherence effects are strongly suppressed, and it may be possible to measure directly the level repulsions at avoided level crossings.Comment: 21 pages, 5 figure

The effect of potassium addition to Pt supported on YSZ on steam reforming of mixtures of methane and ethane

The influence of potassium addition on Pt supported on yttrium-stabilized zirconia (YSZ) was studied with FT-IR CO adsorption and CO-FT-IR-TPD, in order to understand the effect of potassium on the performance of the catalyst in reforming of mixtures of methane and ethane. Potassium modification of PtYSZ strongly influenced the conversion and rate determining steps in methane and ethane in steam reforming. Water activation is the rate determining step on PtYSZ, resulting in high surface coverage of hydrocarbon fragments during steam reforming of mixtures of methane and ethane. This led to blocking of active sites by ethane fragments and consequently low conversion of methane. If potassium is added to the catalyst, hydrocarbon activation on Pt is rate determining, resulting in low surface coverage of methane and ethane. As a result, competition effects of methane and ethane diminished on potassium modified PtYSZ, enabling simultaneous conversion of methane and ethane. The weakening of the interaction of the hydrocarbons with the Pt surface as a result of potassium addition is supported by the fact that the interaction with CO is weakened, as observed with FT-IR-TPD

Pelvic floor muscles after birth : do unstable shoes have an effect on pelvic floor activity and can this be measured reliably? – a feasibility study

Background: Women often suffer from urinary incontinence after childbirth. Pelvic floor muscle training is an evidenced-based intervention to prevent urinary incontinence and improve its symptoms Aim: The primary purpose of this study was to determine if there is a change in the activation of the pelvic floor muscles with different extrinsic parameters (barefoot versus unstable shoe). Second, we wanted to define variables that can be measured reliably and correlated with pelvic floor activity. Methods: Data of 15 women who were 8 weeks to 6 months postpartum were analyzed. Two conditions (“barefoot” and “kyBoot”) were tested, with each participant performing three different tasks: walking, standing with an active pelvic floor, and standing with a passive pelvic floor. Three-dimensional kinematics of the body were recorded. Activity of the abdominal, back, and gluteal muscles was measured using surface electromyography (EMG). The activity of the pelvic floor was recorded using a vaginal electrode. Maximum pelvic floor activity was compared for each condition, and correlations among pelvic floor activity, kinematic variables, and skeletal muscle activity were determined. Results: The maximum activity of the pelvic floor while walking was significantly higher when participants were barefoot than when they were wearing kyBoot shoes. For the standing trials, no significant differences between the conditions were detected. No surrogate marker was found to measure the pelvic floor activity. Conclusion: With regard to the pelvic floor musculature, no recommendation is possible in favor of or against wearing unstable shoes. Technical developments are necessary to provide solutions to reliably measure the pelvic floor activity

19F nuclear spin relaxation and spin diffusion effects in the single ion magnet LiYF4:Ho3+

Temperature and magnetic field dependences of the 19F nuclear spin-lattice relaxation in a single crystal of LiYF4 doped with holmium are described by an approach based on a detailed consideration of the magnetic dipole-dipole interactions between nuclei and impurity paramagnetic ions and nuclear spin diffusion processes. The observed non-exponential long time recovery of the nuclear magnetization after saturation at intermediate temperatures is in agreement with predictions of the spin-diffusion theory in a case of the diffusion limited relaxation. At avoided level crossings in the spectrum of electron-nuclear states of the Ho3+ ion, rates of nuclear spin-lattice relaxation increase due to quasi-resonant energy exchange between nuclei and paramagnetic ions, in contrast to the predominant role played by electronic cross-relaxation processes in the low-frequency ac-susceptibility.Comment: 27 pages total, 5 figures, accepted for publication, Eur. Phys. J.

Ausländische nicht-akademische Fachkräfte auf dem deutschen Arbeitsmarkt

AUSLÄNDISCHE NICHT-AKADEMISCHE FACHKRÄFTE AUF DEM DEUTSCHEN ARBEITSMARKT Ausländische nicht-akademische Fachkräfte auf dem deutschen Arbeitsmarkt / Graf, Johannes (Rights reserved) ( -

Ausländische nicht-akademische Fachkräfte auf dem deutschen Arbeitsmarkt: eine Bestandsaufnahme vor dem Inkrafttreten des Fachkräfteeinwanderungsgesetzes

In vielen Arbeitsmarktbereichen und Regionen Deutschlands kommt es bereits heute zu Engpässen bei der Besetzung von Stellen, die eine qualifizierte Berufsausbildung erfordern. Die Bundesregierung sieht dies als eine zentrale Herausforderung für die kommenden Jahre und nimmt in ihrer Fachkräftestrategie auch Menschen aus Ländern außerhalb der EU in den Blick. Bereits 2013 verbesserte sich für Migrantinnen und Migranten mit Berufsausbildung der Zugang zum Arbeitsmarkt. Den Weg dafür ebnete eine Änderung der Beschäftigungsverordnung. Seitdem konnten qualifizierte Fachkräfte aus Nicht-EU-Staaten unter bestimmten Umständen für so genannte "Engpassberufe" (wie z.B. Bauelektriker/-in, Krankenpfleger/-in) nach Deutschland kommen. Mit dem Fachkräfteeinwanderungsgesetz, welches am 1. März 2020 in Kraft tritt, werden diese Möglichkeiten erweitert. Das BAMF-Forschungszentrum analysiert in dem Forschungsbericht "Ausländische nicht-akademische Fachkräfte auf dem deutschen Arbeitsmarkt" die Ausgangslage vor dem Inkrafttreten des Gesetzes. Der Bericht bietet eine Grundlage für eine spätere Betrachtung von Umsetzung und Wirkungsweise des Gesetzes. Die Basis hierfür bilden eine Darstellung der rechtlichen Grundlagen und des aktuellen Standes der Forschung. Des Weiteren wurden Daten der Bundesagentur für Arbeit sowie des Ausländerzentralregisters zur Einreise und Beschäftigung ausländischer nicht-akademischer Fachkräfte in Deutschland ausgewertet.Shortages are already occurring in many labour market sectors and regions of Germany when it comes to filling vacancies that require qualified vocational training. The Federal Government views this as a key challenge for the coming years and also takes people from countries outside the EU into account in its Skilled Labour Strategy. Access to the labour market for migrants with vocational training improved as far back as 2013. An amendment to the Ordinance on the admission of foreigners for the purpose of taking up employment (Employment Regulation) (Beschäftigungsverordnung) paved the way for this. Since then, qualified skilled workers from non-EU countries have been able to come to Germany under certain circumstances to fill vacancies in so-called "shortage occupations" (such as building electricians, nurses). These opportunities are being expanded with the Skilled Immigration Act (Fachkräfteeinwanderungsgesetz), which enters into force on 1 March 2020. In the research report entitled "Ausländische nicht-akademische Fachkräfte auf dem deutschen Arbeitsmarkt" (Foreign non-academic skilled workers on the German labour market), the Research Centre of the Federal Office for Migration and Refugees analyses the situation that currently prevails before the Skilled Immigration Act enters into force. The report provides the basis for a later examination of the implementation and effect of the Act. The report starts with a presentation of the legal foundations and the current state of research. In addition, data from the Federal Labour Office and the Central Register of Foreigners on the entry and employment of foreign non-academic skilled workers in Germany were evaluated

Nachhaltige Raumentwicklung für die große Transformation - zusammenführende Diskussion und Schlussfolgerungen

Auf Basis der im Arbeitskreis konsensual vertretenen Überzeugung, dass Raumentwicklung und Raumplanung wesentliche Akteure auf dem Weg des gesellschaftlichen Wandels in eine nachhaltige Raumentwicklung sind, werden im Beitrag die zentralen Ergebnisse der gemeinsamen Arbeit am Thema dargestellt. Die Autorinnen weisen zunächst auf die Annahme hin, dass die Umsetzung des Leitziels der nachhaltigen Raumentwicklung eines Prozesses bedarf, dessen Gestaltung unterschiedlichen Weltbildern unterliegt, über die es sich zu verständigen gilt. Im Arbeitskreis hatte ein solcher Verständigungsprozess dazu geführt, dass die Grundprinzipien im Umgang mit der derzeit nicht-nachhaltigen (räumlichen) Entwicklung benannt wurden. In einer sozialökologischen Perspektive werden die Gebote intra- und intergenerationaler Gerechtigkeit, die Gemeinwohlorientierung der Raumentwicklung und -planung sowie das Ziel der Daseinsvorsorge hervorgehoben. Auf dieser Grundlage und mit dem Blick auf die zentralen Akteure der Transformation sowie auf die Rolle des (gestaltenden) Staates werden die aus Sicht des Arbeitskreises wichtigsten Handlungsfelder identifiziert und in Hinblick auf Transformationserfordernisse betrachtet. Unter der Prämisse, dass Regionalentwicklung das entscheidende Handlungsfeld der großen Transformation ist, sind es u. a. die Themenbereiche Wohnen, Digitalisierung, Energie, Mobilität und Ernährung, die als besonders steuerungsrelevante Bereiche gelten können und hinsichtlich der Steuerungsmöglichkeiten durch räumliche Planung diskutiert wurden. Das Fazit wird abgerundet durch eine Zusammenführung der zentralen Handlungsund Forschungsbedarfe, wie sie von den beteiligten Expertinnen und Experten im Rahmen ihrer jeweils spezifischen Beiträge im Band herausgearbeitet wurden.Based on the consensus among the working group that spatial development and spatial planning are very important actors on the path of social change towards sustainable spatial development, the chapter presents the key findings of joint work on the topic. The authors direct attention to the notion that implementation of the goal of sustainable spatial development requires a process which is subject to the influence of different worldviews. In the process of gaining understanding of these worldviews, the working group identified, inter alia, the basic principles used when dealing with the present non-sustainable (spatial) development: from a social-ecological perspective, the precepts of intra- and inter-generational justice, spatial development and planning for the common good, and the goal of services of general interest were highlighted. Building on this foundation and considering key actors of the transformation and the role of the (formative) state, the working group identified what they believe to be the most important fields of action and examined these with a view to the requirements of transformation. Based on the premise that regional development represents the crucial sphere of action for the great transformation, the most relevant fields include housing, digitalisation, energy, mobility and food; these are discussed in terms of possibilities for intervention by spatial planning. The conclusion culminates with a summary of the key needs for action and research requirements as identified by the experts involved in their specific contributions to the volume