Universal decay law in charged-particle emission and exotic cluster radioactivity

A linear universal decay formula is presented starting from the microscopic mechanism of the charged-particle emission. It relates the half-lives of monopole radioactive decays with the $Q$-values of the outgoing particles as well as the masses and charges of the nuclei involved in the decay. This relation is found to be a generalization of the Geiger-Nuttall law in $\alpha$ radioactivity and explains well all known cluster decays. Predictions on the most likely emissions of various clusters are presented.Comment: 2 figure

Photomedicine of the endometrium: experimental concepts

Gynaecological photomedicine offers new diagnostic and therapeutic methods based on the interaction of light with the reproductive organs. One example is photodynamic therapy (PDT) in which photosensitizers are applied systemically or topically for selective endometrial ablation. Several studies describing the potential use of PDT for this application are reviewed. Basic experimental and clinical aspects of PDT, such as photosensitizer types, application modes, irradiation parameters, optical properties of tissues and photodegradation of photosensitizers are discusse

Gesellschaftliche Leistungen der biologischen Landwirtschaft

Zusammenfassuung: In diesem Bericht werden die wissenschaftlichen Ergebnisse nationaler und internationaler Studien zu den gesellschaftlichen Leistungen des Biolandbaus zusammengefasst. Als Referenzen werden dabei sowohl die konventionelle wie auch die integrierte Landwirtschaft herangezogen. Es ist den Autoren bewusst, dass alle Landwirtschaftsmethoden in der Schweiz und im Ausland eine grosse Streubreite aufweisen, da der Einfluss der regionalen sozioökonomischen Rahmenbedingungen, der Standortfaktoren, der Betriebsleiter und der unterschiedlichen staatlichen und privaten Regulierungen gross ist. Trotzdem ergeben sich für die verschiedenen Landwirtschaftsmethoden klare Unterschiede, die bei den agrarpolitischen Massnahmen berücksichtigt werden müssen. Bezüglich der positiven Externalitäten weist der Biolandbau klare Mehrleistungen in der Biodiversität auf. Dies sowohl auf der Ebene der Genetik, der Arten und besonders auch der Habitate. Deutlich sind die Mehrleistungen des Biolandbaus auch im Bereich des Humusaufbaus, was eine höhere CO2-Sequestrierung zur Folge hat. Obwohl eine dauerhafte Honorierung der Vermeidung negativer Externalitäten im bisherigen Konzept der Weiterentwicklung des Direktzahlungssystems (WDZ) nicht vorgesehen ist, sind hier die Vorteile der biologischen Landwirtschaft beträchtlich. Dies betrifft die Nährstoff- und Pflanzenschutzmittelverluste in Grund- und Oberflächengewässer sowie in andere Umweltkompartimente, der Verbrauch von nicht erneuerbarer Energie, die Emissionen von Klimagasen und die Belastungen mit Tiermedikamenten. Die nationalen und internationalen Studien zeigen auf, dass der Biolandbau sich besonders durch Systemwirkungen auszeichnet: erhöhte Biodiversität, verbesserter Schutz des Bodens, wirksame Vermeidung von Umweltbelastungen, effiziente Nutzung von natürlichen Ressourcen, geringer Verbrauch nicht erneuerbarer Energie und verbessertes Tierwohl. Dies sind die Effekte von komplexen Response-Massnahmen der Betriebsleiter auf einfach zu kontrollierende Einschränkungen und Verbote. Dadurch entstehen nicht zu unterschätzende Zusatzleistungen und Synergien bei der Erreichung der vom Bund definierten Ziele. Um den Mehrleistungen des Biolandbaus gerecht zu werden, schlagen die Autoren zwei neue Massnahmen vor: 1) Biodiversitätsbeitrag für Acker, Sonderkulturen und intensive Wiesen und 2) CO2-Sequestrationsbeiträge. Damit sind aber die gesellschaftlich wichtigen Mehrleistungen des Biolandbaus noch nicht abgegolten. Bei der Vermeidung negativer Externalitäten werden höhere umweltschutzrelevante Effekte erzielt. Diese können i) durch die Einführung eines negativen Anreizsystems nach dem Polluter-Pays-Principle (z.B. Stickstoffsteuer, CO2 - Abgabe), ii) durch ein höheres Einstiegsniveau bei den Cross-Compliance-Massnahmen für alle Betriebe (ÖLNplus) oder iii) durch einen finanziellen Ausgleich für die Mehrleistungen des Biolandbaus abgegolten werden. Die „Förderung des Biolandbaus“ als systemorientierte Massnahme macht auch nach dem Grundsatz des effizienten Einsatzes von Steuermitteln Sinn und stellt eine kosteneffektive Massnahme dar. Einerseits können damit die deutlich höheren positiven Externalitäten abgegolten werden, andererseits wird die stärkere Vermeidung von negativen Externalitäten genügend berücksichtigt

Alpha Decay Hindrance Factors: A Probe of Mean Field Wave Functions

A simple model to calculate alpha-decay Hindrance Factors is presented. Using deformation values obtained from PES calculations as the only input, Hindrance Factors for the alpha-decay of Rn- and Po-isotopes are calculated. It is found that the intrinsic structure around the Fermi surface determined by the deformed mean field plays an important role in determining the hindrance of alpha-decay. The fair agreement between experimental and theoretical Hindrance Factors suggest that the wave function obtained from the energy minima of the PES calculations contains an important part of the correlations that play a role for the alpha-decay. The calculated HF that emerges from these calculations render a different interpretation than the commonly assumed n-particle n-hole picture.Comment: 7 pages, 9 figure

Abrupt changes in alpha decay systematics as a manifestation of collective nuclear modes

An abrupt change in $\alpha$ decay systematics around the N=126 neutron shell closure is discussed. It is explained as a sudden hindrance of the clustering of the nucleons that eventually form the $\alpha$ particle. This is because the clustering induced by the pairing mode acting upon the four nucleons is inhibited if the configuration space does not allow a proper manifestation of the pairing collectivity.Comment: 6 pages, 3 figures, submitted to Phys. Rev. C, a few new references adde

Can Action Research Strengthen District Health Management and Improve Health Workforce Performance? A Research Protocol.

The single biggest barrier for countries in sub-Saharan Africa (SSA) to scale up the necessary health services for addressing the three health-related Millennium Development Goals and achieving Universal Health Coverage is the lack of an adequate and well-performing health workforce. This deficit needs to be addressed both by training more new health personnel and by improving the performance of the existing and future health workforce. However, efforts have mostly been focused on training new staff and less on improving the performance of the existing health workforce. The purpose of this paper is to disseminate the protocol for the PERFORM project and reflect on the key challenges encountered during the development of this methodology and how they are being overcome. The overall aim of the PERFORM project is to identify ways of strengthening district management in order to address health workforce inadequacies by improving health workforce performance in SSA. The study will take place in three districts each in Ghana, Tanzania and Uganda using an action research approach. With the support of the country research teams, the district health management teams (DHMTs) will lead on planning, implementation, observation, reflection and redefinition of the activities in the study. Taking into account the national and local human resource (HR) and health systems (HS) policies and practices already in place, 'bundles' of HR/HS strategies that are feasible within the context and affordable within the districts' budget will be developed by the DHMTs to strengthen priority areas of health workforce performance. A comparative analysis of the findings from the three districts in each country will add new knowledge on the effects of these HR/HS bundles on DHMT management and workforce performance and the impact of an action research approach on improving the effectiveness of the DHMTs in implementing these interventions. Different challenges were faced during the development of the methodology. These include the changing context in the study districts, competing with other projects and duties for the time of district managers, complexity of the study design, maintaining the anonymity and confidentiality of study participants as well as how to record the processes during the study. We also discuss how these challenges are being addressed. The dissemination of this research protocol is intended to generate interest in the PERFORM project and also stimulate discussion on the use of action research in complex studies such as this on strengthening district health management to improve health workforce performance

Microscopic structure of fundamental excitations in N=Z nuclei

Excitation energies of the $T$=1 states in even-even as well as $T$=0 and $T$=1 states in odd-odd $N$=$Z$ nuclei are calculated within the mean-field approach. It is shown that the underlying structure of these states can be determined in a consistent manner only when both isoscalar and isovector pairing collectivity as well as isospin projection, treated within the iso-cranking approximation, are taken into account. In particular, in odd-odd $N$=$Z$ nuclei, the interplay between quasiparticle excitations (relevant for the case of $T$=0 states) and iso-rotations (relevant for the case of $T$=1 states) explains the near-degeneracy of these fundamental excitations.Comment: 4 pages, 4 figure

Glasslike Arrest in Spinodal Decomposition as a Route to Colloidal Gelation

Colloid-polymer mixtures can undergo spinodal decomposition into colloid-rich and colloid-poor regions. Gelation results when interconnected colloid-rich regions solidify. We show that this occurs when these regions undergo a glass transition, leading to dynamic arrest of the spinodal decomposition. The characteristic length scale of the gel decreases with increasing quench depth, and the nonergodicity parameter exhibits a pronounced dependence on scattering vector. Mode coupling theory gives a good description of the dynamics, provided we use the full static structure as input.Comment: 14 pages, 4 figures; replaced with published versio

Optical Properties of Human Uterus at 630 nm

The optical properties of normal and fibriotic human uteri were determined using frequency-domain and steady-state techniques

Magnetization reversal of an individual exchange biased permalloy nanotube

We investigate the magnetization reversal mechanism in an individual permalloy (Py) nanotube (NT) using a hybrid magnetometer consisting of a nanometer-scale SQUID (nanoSQUID) and a cantilever torque sensor. The Py NT is affixed to the tip of a Si cantilever and positioned in order to optimally couple its stray flux into a Nb nanoSQUID. We are thus able to measure both the NT's volume magnetization by dynamic cantilever magnetometry and its stray flux using the nanoSQUID. We observe a training effect and temperature dependence in the magnetic hysteresis, suggesting an exchange bias. We find a low blocking temperature $T_B = 18 \pm 2$ K, indicating the presence of a thin antiferromagnetic native oxide, as confirmed by X-ray absorption spectroscopy on similar samples. Furthermore, we measure changes in the shape of the magnetic hysteresis as a function of temperature and increased training. These observations show that the presence of a thin exchange-coupled native oxide modifies the magnetization reversal process at low temperatures. Complementary information obtained via cantilever and nanoSQUID magnetometry allows us to conclude that, in the absence of exchange coupling, this reversal process is nucleated at the NT's ends and propagates along its length as predicted by theory.Comment: 8 pages, 4 figure