Altern und Sexualität

Dieser Beitrag gibt einen einführenden Überblick zum sexuellen Verhalten und Erleben von Menschen im mittleren und höheren Erwachsenenalter. Grundlage dafür ist eine Studie aus der deutschsprachigen Schweiz mit 641Männern (45-91Jahre) und 857Frauen (45-86Jahre). Altersbedingte hormonale und anatomische Veränderungen und deren Auswirkungen auf die sexuellen Reaktionen werden kurz beschrieben. Sexuelles Interesse, sexuelle Aktivität und Zufriedenheit, gesundheitliche Einflüsse darauf sowie Gründe sexueller Inaktivität werden dargestellt. Die Medikalisierung der Sexualität alternder Menschen wird kritisch beleuchtet. Zusammenfassende Empfehlungen für die Praxis werden gegebe

Thermal phase transitions for Dicke-type models in the ultra-strong coupling limit

We consider the Dicke model in the ultra-strong coupling limit to investigate thermal phase transitions and their precursors at finite particle numbers $N$ for bosonic and fermionic systems. We derive partition functions with degeneracy factors that account for the number of configurations and derive explicit expressions for the Landau free energy. This allows us to discuss the difference between the original Dicke (fermionic) and the bosonic case. We find a crossover between these two cases that shows up, e.g., in the specific heat.Comment: 4 pages Brief Report styl

Observation of Modulated Quadrupolar Structures in PrPb3

Neutron diffraction measurements have been performed on the cubic compound PrPb3 in a [001] magnetic field to examine the quadrupolar ordering. Antiferromagnetic components with q=(1/2+-d 1/2 0), (1/2 1/2+-d 0) (d~1/8) are observed below the transition temperature TQ (0.4 K at H=0) whose amplitudes vary linear with H and vanish at zero field, providing the first evidence for a modulated quadrupolar phase. For H<1 T, a non-square modulated state persists even below 100 mK suggesting quadrupole moments associated with a Gamma3 doublet ground state to be partially quenched by hybridization with conduction electrons.Comment: Physical Review Letters, in press. 4 pages, 4 figure

Antiferro-quadrupole state of orbital-degenerate Kondo lattice model with f^2 configuration

To clarify a key role of $f$ orbitals in the emergence of antiferro-quadrupole structure in PrPb$_{3}$, we investigate the ground-state property of an orbital-degenerate Kondo lattice model by numerical diagonalization techniques. In PrPb$_{3}$, Pr$^{3+}$ has a $4f^{2}$ configuration and the crystalline-electric-field ground state is a non-Kramers doublet $\Gamma_{3}$. In a $j$-$j$ coupling scheme, the $\Gamma_{3}$ state is described by two local singlets, each of which consists of two $f$ electrons with one in $\Gamma_{7}$ and another in $\Gamma_{8}$ orbitals. Since in a cubic structure, $\Gamma_{7}$ has localized nature, while $\Gamma_{8}$ orbitals are rather itinerant, we propose the orbital-degenerate Kondo lattice model for an effective Hamiltonian of PrPb$_{3}$. We show that an antiferro-orbital state is favored by the so-called double-exchange mechanism which is characteristic of multi-orbital systems.Comment: 3 pages, 3 figures, Proceedings of Skutterudite2007 (September 26-30, 2007, Kobe

Erektile Dysfunktion bei Männern in der zweiten Lebenshälfte

Zusammenfassung: Hintergrund: Bisherige Studien zur Prävalenz der erektilen Dysfunktion (ED) zeigen unterschiedliche Ergebnisse. Mit der vorliegenden Studie werden die Häufigkeit und graduelle Ausprägung der ED, deren begünstigende Faktoren sowie das Hilfesuchverhalten der Betroffenen untersucht. Stichprobe und Methodik: Eine Zufallsstichprobe von 628 Deutschschweizer Männern (Durchschnittsalter 61,5Jahre) wurde mittels Fragebogen zur sexuellen Funktionsfähigkeit, Komorbidität und zu ihrem Hilfesuchverhalten befragt. Ergebnisse: 9,6% der Befragten berichten über eine vollständige, 18,0% über eine moderate und 41,4% über eine minimale ED. Alle Grade der Störung nehmen mit dem Alter zu und korrelieren mit somatischer bzw. psychischer Komorbidität sowie Medikamenteneinnahme. Nur 3,2% geben an, schon Mittel zur Verbesserung der Erektionsfähigkeit eingenommen bzw. verwendet zu haben. Schlussfolgerungen: Nur ein kleiner Teil von Männern mit ED sucht ärztliche Hilfe. Sachliche Aufklärung und kompetente ärztliche Beratung von Betroffenen erscheinen angesichts der guten Wirksamkeit von PDE-5-Hemmern angebrach

On applications and limitations of one-dimensional capillarity formulations for media with heterogeneous wettability

Force-balance-based one-dimensional algebraic formulations that are often used in characterizing the capillarity of a multi-component system (e.g., predicting capillary height rise inporous media) are discussed. It is shown that such formulations fail to provide accurate predictions when the distribution of wetting (or non-wetting) surfaces is not homogeneous. A more general mathematical formulation is suggested and used to demonstrate that for media with heterogeneous wettability, hydrophilic (or hydrophobic) surfaces clustered in groups will have less contribution to the overall capillarity of the system

A note on semi-conjugacy for circle actions

We define a notion of semi-conjugacy between orientation-preserving actions of a group on the circle, which for fixed point free actions coincides with a classical definition of Ghys. We then show that two circle actions are semi-conjugate if and only if they have the same bounded Euler class. This settles some existing confusion present in the literature

Kinefold web server for RNA/DNA folding path and structure prediction including pseudoknots and knots

The Kinefold web server provides a web interface for stochastic folding simulations of nucleic acids on second to minute molecular time scales. Renaturation or co-transcriptional folding paths are simulated at the level of helix formation and dissociation in agreement with the seminal experimental results. Pseudoknots and topologically ‘entangled’ helices (i.e. knots) are efficiently predicted taking into account simple geometrical and topological constraints. To encourage interactivity, simulations launched as immediate jobs are automatically stopped after a few seconds and return adapted recommendations. Users can then choose to continue incomplete simulations using the batch queuing system or go back and modify suggested options in their initial query. Detailed output provide (i) a series of low free energy structures, (ii) an online animated folding path and (iii) a programmable trajectory plot focusing on a few helices of interest to each user. The service can be accessed at