Supernova Inelastic Neutrino-Nucleus Cross Sections from High-Resolution Electron Scattering Experiments and Shell-Model Calculations

Highly precise data on the magnetic dipole strength distributions from the Darmstadt electron linear accelerator for the nuclei 50Ti, 52Cr and 54Fe are dominated by isovector Gamow-Teller-like contributions and can therefore be translated into inelastic total and differential neutral-current neutrino-nucleus cross sections at supernova neutrino energies. The results agree well with large-scale shell-model calculations, validating this model.Comment: 5 pages, 4 figures, RevTeX 4, version accepted in Phys. Rev. Letter

Investigation of teacher’s health in a mixed-methods-design study using videography

Basierend auf dem Systemischen Anforderungs-Ressourcen-Modell (Becker, 2006) wurden in dieser Studie (1) im Mixed-Methods-Design die Gesundheit von 19 Lehrern untersucht, (2) Anforderungen und Ressourcen im Unterricht mittels Videografien erhoben und (3) in einer fallkontrastierenden Typenbildung trianguliert. Es zeigte sich, dass neben einem engagierten und disziplinierten Schülerverhalten, die Klassenführung - kombiniert mit einer hohen Sozialkompetenz - sowie die verwendeten Unterrichtsmethoden wichtige Ressourcen für Lehrer darstellen. (DIPF/Orig.)In this study the systemic demands-resources model (Becker, 2006) was applied (1) to investigate the health condition of teachers using a mixed-methods-design, (2) to ascertain the demands and resources during lessons using videography and (3) to triangulate the data in a case contrasting typification. It was observed that, in addition to the committed and disciplined behavior of students, classroom management combined with high social competence and the applied teaching methods represent crucial resources for teachers. (DIPF/Orig.

The incredible ULKs

Macroautophagy (commonly abbreviated as autophagy) is an evolutionary conserved lysosome-directed vesicular trafficking pathway in eukaryotic cells that mediates the lysosomal degradation of intracellular components. The cytoplasmic cargo is initially enclosed by a specific double membrane vesicle, termed the autophagosome. By this means, autophagy either helps to remove damaged organelles, long-lived proteins and protein aggregates, or serves as a recycling mechanism for molecular building blocks. Autophagy was once invented by unicellular organisms to compensate the fluctuating external supply of nutrients. In higher eukaryotes, it is strongly enhanced under various stress conditions, such as nutrient and growth factor deprivation or DNA damage. The serine/threonine kinase Atg1 was the first identified autophagy-related gene (ATG) product in yeast. The corresponding nematode homolog UNC-51, however, has additional neuronal functions. Vertebrate genomes finally encode five closely related kinases, of which UNC-51-like kinase 1 (Ulk1) and Ulk2 are both involved in the regulation of autophagy and further neuron-specific vesicular trafficking processes. This review will mainly focus on the vertebrate Ulk1/2-Atg13-FIP200 protein complex, its function in autophagy initiation, its evolutionary descent from the yeast Atg1-Atg13-Atg17 complex, as well as the additional non-autophagic functions of its components. Since the rapid nutrient- and stress-dependent cellular responses are mainly mediated by serine/threonine phosphorylation, it will summarize our current knowledge about the relevant upstream signaling pathways and the altering phosphorylation status within this complex during autophagy induction

Differential Regulation and ATP Requirement for Caspase-8 and Caspase-3 Activation during CD95- and Anticancer Drug–induced Apoptosis

Apoptosis is induced by different stimuli, among them triggering of the death receptor CD95, staurosporine, and chemotherapeutic drugs. In all cases, apoptosis is mediated by caspases, although it is unclear how these diverse apoptotic stimuli cause protease activation. Two regulatory pathways have been recently identified, but it remains unknown whether they are functionally independent or linked to each other. One is mediated by recruitment of the proximal regulator caspase-8 to the death receptor complex. The other pathway is controlled by the release of cytochrome c from mitochondria and the subsequent ATP-dependent activation of the death regulator apoptotic protease-activating factor 1 (Apaf-1). Here, we report that both pathways can be dissected by depletion of intracellular ATP. Prevention of ATP production completely inhibited caspase activation and apoptosis in response to chemotherapeutic drugs and staurosporine. Interestingly, caspase-8, whose function appeared to be restricted to death receptors, was also activated by these drugs under normal conditions, but not after ATP depletion. In contrast, inhibition of ATP production did not affect caspase activation after triggering of CD95. These results suggest that chemotherapeutic drug–induced caspase activation is entirely controlled by a receptor-independent mitochondrial pathway, whereas CD95-induced apoptosis can be regulated by a separate pathway not requiring Apaf-1 function

Magnetic Dipole Sum Rules for Odd-Mass Nuclei

Sum rules for the total- and scissors-mode M1 strength in odd-A nuclei are derived within the single-j interacting boson-fermion model. We discuss the physical content and geometric interpretation of these sum rules and apply them to ^{167}Er and ^{161}Dy. We find consistency with the former measurements but not with the latter.Comment: 13 pages, Revtex, 1 figure, Phys. Rev. Lett. in pres

The mycotoxin phomoxanthone A disturbs the form and function of the inner mitochondrial membrane.

Mitochondria are cellular organelles with crucial functions in the generation and distribution of ATP, the buffering of cytosolic Ca2+ and the initiation of apoptosis. Compounds that interfere with these functions are termed mitochondrial toxins, many of which are derived from microbes, such as antimycin A, oligomycin A, and ionomycin. Here, we identify the mycotoxin phomoxanthone A (PXA), derived from the endophytic fungus Phomopsis longicolla, as a mitochondrial toxin. We show that PXA elicits a strong release of Ca2+ from the mitochondria but not from the ER. In addition, PXA depolarises the mitochondria similarly to protonophoric uncouplers such as CCCP, yet unlike these, it does not increase but rather inhibits cellular respiration and electron transport chain activity. The respiration-dependent mitochondrial network structure rapidly collapses into fragments upon PXA treatment. Surprisingly, this fragmentation is independent from the canonical mitochondrial fission and fusion mediators DRP1 and OPA1, and exclusively affects the inner mitochondrial membrane, leading to cristae disruption, release of pro-apoptotic proteins, and apoptosis. Taken together, our results suggest that PXA is a mitochondrial toxin with a novel mode of action that might prove a useful tool for the study of mitochondrial ion homoeostasis and membrane dynamics

Orbital M1 versus E2 strength in deformed nuclei: A new energy weighted sum rule

Within the unified model of Bohr and Mottelson we derive the following linear energy weighted sum rule for low energy orbital 1$^+$ excitations in even-even deformed nuclei S_{\rm LE}^{\rm lew} (M_1^{\rm orb}) \cong (6/5) \epsilon (B(E2; 0^+_1 \rightarrow 2_1^+ K=0)/Z e^2^2) \mu^2_N with B(E2) the E2 strength for the transition from the ground state to the first excited state in the ground state rotational band, $$ the charge r.m.s. radius squared and $\epsilon$ the binding energy per nucleon in the nuclear ground state. It is shown that this energy weighted sum rule is in good agreement with available experimental data. The sum rule is derived using a simple ansatz for the intrinsic ground state wave function that predicts also high energy 1$^+$ strength at 2$\hbar \omega$ carrying 50\% of the total $m_1$ moment of the orbital M1 operator.Comment: REVTEX (3.0), 9 pages, RU924

Level density and gamma strength function in 162-Dy from inelastic 3-He scattering

Complementary measurements have been performed for the level density and gamma strength function in 162-Dy using inelastic 3-He scattering. Comparing these results to previous measurements using the 163-Dy(3-He,alpha) reaction, reveals that the measured quantities above 1.5 MeV do not depend significantly on the nuclear reaction chosen.Comment: 15 pages, including 7 figure

Level density and thermal properties in rare earth nuclei

A convergent method to extract the nuclear level density and the gamma-ray strength function from primary gamma-ray spectra has been established. Thermodynamical quantities have been obtained within the microcanonical and canonical ensemble theory. Structures in the caloric curve and in the heat capacity curve are interpreted as fingerprints of breaking of Cooper pairs and quenching of pairing correlations. The strength function can be described using models and common parameterizations for the E1, M1 and pygmy resonance strength. However, a significant decrease of the pygmy resonance strength at finite temperatures has been observed.Comment: 15 pages including 8 figures. Proceedings article for the conference Nuclear Structure and Related Topics, Dubna, Russia, June 6-10, 200