Nucleosynthesis of 92^{92}Nb and the relevance of the low-lying isomer at 135.5 keV

Background: Because of its half-life of about 35 million years, 92Nb is considered as a chronometer for nucleosynthesis events prior to the birth of our sun. The abundance of 92Nb in the early solar system can be derived from meteoritic data. It has to be compared to theoretical estimates for the production of 92Nb to determine the time between the last nucleosynthesis event before the formation of the early solar system. Purpose: The influence of a low-lying short-lived isomer on the nucleosynthesis of 92Nb is analyzed. The thermal coupling between the ground state and the isomer via so-called intermediate states affects the production and survival of 92Nb. Method: The properties of the lowest intermediate state in 92Nb are known from experiment. From the lifetime of the intermediate state and from its decay branchings, the transition rate from the ground state to the isomer and the effective half-life of 92Nb are calculated as a function of the temperature. Results: The coupling between the ground state and the isomer is strong. This leads to thermalization of ground state and isomer in the nucleosynthesis of 92Nb in any explosive production scenario and almost 100% survival of 92Nb in its ground state. However, the strong coupling leads to a temperature-dependent effective half-life of 92Nb which makes the 92Nb survival very sensitive to temperatures as low as about 8 keV, thus turning 92Nb at least partly into a thermometer. Conclusions: The low-lying isomer in 92Nb does not affect the production of 92Nb in explosive scenarios. In retrospect this validates all previous studies where the isomer was not taken into account. However, the dramatic reduction of the effective half-life at temperatures below 10 keV may affect the survival of 92Nb after its synthesis in supernovae which are the most likely astrophysical site for the nucleosynthesis of 92Nb.Comment: 5 pages, 3 figures; Phys. Rev. C, accepted for publicatio

Shy or sociable : introversion/extraversion and message recall

textPersonality research has long been an area of interest in the study of consumer behavior. Currently, common practice is to segment prospective audiences by demographic variables (age, gender, and race) instead of psychographics (values, attitudes, personality). In this research, the author investigates the relationship between personality type (introversion/extraversion) and message recall. Using 122 undergraduate and graduate students, recall was examined across two forms of stimulus (incongruent and congruent messages). Results indicated that while there is no relationship between personality type and message recall, there is a relationship between the frequency of advertising messaging and recall. Results are discussed individually by messaging frequency and personality type with further suggestions for future research.Advertisin

The association between parent's and healthcare professional's behavior and children's coping and distress during venepuncture

Objectives: Examine the association between children’s distress and coping during venepuncture with parent’s and healthcare professional’s behavior in a sample from the UK. Methods: Fifty children aged 7–16 years accompanied by a carer were videotaped while having venepuncture. Verbalizations of children, parents, and healthcare professionals were coded using the Child–Adult Medical Procedure Interaction Scale-Revised. Results: Children’s distress was associated with child’s age, anxiety, and distress promoting behavior of adults (R2 = .91). Children’s coping was associated with age, anxiety, and coping promoting behaviors of adults (R2 = .57). Associations were stronger between healthcare professional’s behavior and child coping; and between parent’s behaviors and child distress. Empathizing, apologizing, and criticism were not frequently used by adults in this sample (<12%). Conclusion: This study supports and extends previous research showing adult’s behavior is important in children’s distress and coping during needle procedures. Clinical implications and methodological issues are discussed

Computation of the radiation characteristics of a generalized phased array

With the advent of monolithic microwave integrated circuit (MMIC) technology, the phased array has become a key component in the design of advanced antenna systems. Array-fed antennas are used extensively in today's multiple beam satellite antennas. A computer program based on a very efficient numerical technique for calculating the radiated power (Romberg integration), directivity, and radiation pattern of a phased array is described. The formulation developed is very general, and takes into account arbitrary element polarization, E- and H-plane element pattern, element location, and complex element excitation. For comparison purposes sample cases have been presented. Excellent agreement has been obtained for all cases. Also included are a user guide and a copy of the computer program

Zirconium stable isotope analysis of zircon by MC-ICP-MS: Methods and application to evaluating intra-crystalline zonation in a zircon megacryst

Zirconium (Zr) plays a key role in the development of phases like zircon (ZrSiO₄) and baddeleyite (ZrO₂) in magmatic systems. These minerals are crucial for the study of geologic time and crustal evolution, and their high resistivity to weathering and erosion results in their preservation on timescales of billions of years. Although zircon and baddeleyite may also preserve a robust record of Zr isotope behavior in high-temperature terrestrial environments, little is known about the factors that control Zr isotope partitioning in magmatic systems, the petrogenetic significance of fractionated compositions, or how these variations are recorded in Zr-rich accessory phases. Here, we describe a new analytical protocol for accurately determining the Zr stable isotope composition of zircon by multicollector-inductively coupled plasma-mass spectrometry (MC-ICP-MS), using the double-spike method to correct for procedural and instrumental mass bias. We apply this technique to test whether zircon crystallization in carbonatite magmatic systems is a driver of Zr isotope fractionation by interrogating the internal zonation of a zircon megacryst from the Mud Tank carbonatite (MTUR1). We find the MTUR1 megacryst to lack internal zoning within analytical uncertainties with a mean μ⁹⁴/⁹⁰Zr_(NIST) = −55 ± 28 ppm (2 SD, n = 151), which suggests that zircon crystallization is not a driver of Zr isotope fractionation in carbonatite magmas. This observation is in stark contrast with those made in silicate magmatic systems, raising the possibility that the bonding environment of Zr⁴⁺ ions may be fundamentally different in carbonatite vs. silicate melts. Because of its remarkable homogeneity, the MTUR1 megacryst is an ideal natural reference material for Zr isotopic analysis of zircon using both solution and spatially resolved methods. The reproducibility of a pure Zr solution and our chemically purified zircon fractions indicate that the external reproducibility of our method is on the order of ±28 ppm for μ⁹⁴/⁹⁰Zr, or ±7 ppm per amu, at 95% confidence

Lifestyles and consumer behavior

In this article, the concept of lifestyle is traced to its early roots in personality psychology and in marketing. In the latter field, many commercial marketing firms have made strong claims as to the explanatory power of lifestyle dimensions, often based on procedures which have been kept secret, but researchers have seldom been able to verify such claims. In spite of this, the approach is very popular, has wide credibility and is often given very favorable media coverage. Probably because of this, it is often considered as a very important and promising approach by administrators working with the regulation of risk and risk communication. It may also be credible in some quarters because it affords a way of ‘explaining’ risk perception as being non-rational. In this paper, we give results from an empirical study of nuclear waste risk perception which is related to a basic risk perception model and three approaches to lifestyles: Kahle’s List of Values, a Swedish adaptation of the ‘Agorame´trie’ approach suggested by a group of French researchers, and Dake and Wildavsky’s Cultural Theory dimensions. It was found that nuclear waste risk perception could be modeled successfully with risk attitudes and perception data (basic model about 65% of the variance explained), but that lifestyle dimensions added virtually nothing to the explanatory power of the model.consumer behavior; lifestyle; risk

Mito, musica e rito nelle raffigurazioni musicali dei pinakes del Persephoneion di Locri Epizefirii (VI-V sec.a.C.)

I pinakes locresi sono tavolette votive in terracotta del VI e V sec. a. C., per la maggior parte rinvenuti in frammenti, nel 1908, da Paolo Orsi, presso l’edicola tesauraria della Mannella a Locri Epizefirii, polis italiota che si distinse per la sua intensa attività cultuale e sacra e la vigile custodia di antichissime tradizioni mitiche e storiche. Nelle rappresentazioni dei coroplasti, talvolta veri artisti, l’ambiente locrese è individuabile attraverso la configurazione di templi dove, accanto a personaggi, animali e oggetti mitici o cultuali, sono riprodotti carri, arredamenti, vesti e drappi, suppellettili di uso e di cosmesi, e scene musicali e di danza. Il soggetto figurativo prevalente nell’intero corpus, costituito da 5360 pinakes, è legato al grande ciclo mitologico della vita di Persephone. Le immagini illustrano il racconto del passaggio di Kore in Persephone, dal suo rapimento da parte di Hades, quando ancora vergine mortale, coglieva fiori sul prato, all’arrivo nel mondo sotterraneo, sino alla preparazione delle nozze e alla festa della presentazione dei doni da parte delle varie divinità alla dea seduta sul trono, sposa di Hades e già sovrana nel regno degli Inferi. Le raffigurazioni dei pinakes sarebbero espressione e concorderebbero con il culto della dea, nella sua duplice qualità di divinità ctonia e di protettrice della fertilità umana, praticato nel santuario della Mannella e dei riti a lei collegati durante i quali, presumibilmente prima delle nozze, le fanciulle dedicavano alla dea le tavolette votive con scene della vita di Persephone, forse considerata metafora di quella delle giovani donne. Nel complesso ideologico dei pinakes di Locri, la musica sembra avere avuto un ruolo nei riti di passaggio dall’adolescenza all’età adulta nell’ambito di una religiosità fortemente legata alla vita sociale

Short-lived Nuclei in the Early Solar System: Possible AGB Sources

(Abridged) We review abundances of short-lived nuclides in the early solar system (ESS) and the methods used to determine them. We compare them to the inventory for a uniform galactic production model. Within a factor of two, observed abundances of several isotopes are compatible with this model. I-129 is an exception, with an ESS inventory much lower than expected. The isotopes Pd-107, Fe-60, Ca-41, Cl-36, Al-26, and Be-10 require late addition to the solar nebula. Be-10 is the product of particle irradiation of the solar system as probably is Cl-36. Late injection by a supernova (SN) cannot be responsible for most short-lived nuclei without excessively producing Mn-53; it can be the source of Mn-53 and maybe Fe-60. If a late SN is responsible for these two nuclei, it still cannot make Pd-107 and other isotopes. We emphasize an AGB star as a source of nuclei, including Fe-60 and explore this possibility with new stellar models. A dilution factor of about 4e-3 gives reasonable amounts of many nuclei. We discuss the role of irradiation for Al-26, Cl-36 and Ca-41. Conflict between scenarios is emphasized as well as the absence of a global interpretation for the existing data. Abundances of actinides indicate a quiescent interval of about 1e8 years for actinide group production in order to explain the data on Pu-244 and new bounds on Cm-247. This interval is not compatible with Hf-182 data, so a separate type of r-process is needed for at least the actinides, distinct from the two types previously identified. The apparent coincidence of the I-129 and trans-actinide time scales suggests that the last actinide contribution was from an r-process that produced actinides without fission recycling so that the yields at Ba and below were governed by fission.Comment: 92 pages, 14 figure files, in press at Nuclear Physics