Role of Umklapp Processes in Conductivity of Doped Two-Leg Ladders

Recent conductivity measurements performed on the hole-doped two-leg ladder material $\mathrm{Sr_{14-x}Ca_xCu_{24}O_{41}}$ reveal an approximately linear power law regime in the c-axis DC resistivity as a function of temperature for $x=11$. In this work, we employ a bosonic model to argue that umklapp processes are responsible for this feature and for the high spectral weight in the optical conductivity which occurs beyond the finite frequency Drude-like peak. Including quenched disorder in our model allows us to reproduce experimental conductivity and resistivity curves over a wide range of energies. We also point out the differences between the effect of umklapp processes in a single chain and in the two-leg ladder.Comment: 10 pages, 2 figure

Exploring Appropriation of Global Cultural Rituals

Adolescents, as a consequence of identification with popular culture, have been described as having homogenous consumption patterns. More recently, however, it has been recognised that ‘glocalisation’ (global practices reworked to fit local contexts) affords an opportunity for differentiation. This paper considers a recent UK phenomenon, namely that of the US high school prom, and seeks to explore the ways in which this ritual has been adopted or adapted as part of youth culture. The method employed here was mixed methods and included in-depth interviews with those who attended a prom in the last three years as well as a questionnaire distributed amongst high school pupils who were anticipating a high school prom. The findings illustrate that the high school prom in the UK is becoming increasingly integrated into the fabric of youth culture although, depending on the agentic abilities employed by the emerging adults in the sample, there is differing appropriation of this ritual event particularly in relation to attitudes towards and motivations for attending the prom. A typology of prom attendees is posited. This paper contributes to our understanding of this practice in a local context

Use of Opuntia ficus-indica (L.) Mill extracts from Brazilian Caatinga as an alternative of natural moisturizer in cosmetic formulations

ABSTRACT The aim of this work was the obtainment of Opuntia fícus-indica (L.) Mill extract for the development of cosmetic formulations and in vivo evaluation of its moisturizing effects. The formulations were tested for preliminary and accelerated stability. Organoleptic characteristics, pH values and rheological behavior were assessed. The evaluation of moisturizing efficacy of the emulsions formulated with 3.0% of Polyacrylamide (and) C13-14 Isoparaffin (and) Laureth-7 containing 1.0 and 3.0% of O. ficus-indica hydroglycolic extract (EHG001) was performed using the capacitance method (Corneometer(r)) and the transepidermal water loss - TEWL evaluation (Tewameter(r)). The emulsions formulated were stable, exhibiting pseudoplastic and thixotropic behavior. The results of evaluation of moisturizing efficacy showed increased skin hydration after five hours by mainly increasing the skin barrier effect. The formulations containing 1.0 and 3.0% of EHG001 enhanced the skin barrier effect by reducing TEWL up to four hours after application. The results observed suggest that O. ficus-indica hydroglycolic extract may act through a humectant and occlusion mechanism

Phylogenomics and the rise of the angiosperms

Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5,6,7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade

Molecular cloning and characterisation of the general control non-derepressible 2 protein kinase from Triticum aestivum

General control non-derepressible 2 (GCN2) is a kinase that functions to sense and respond to amino acid starvation. GCN2 was first identified in yeast where it senses a reduction in cellular amino acid concentration and responds by phosphorylating the eukaryotic translation initiation factor 2 (eIF2), which is one of the principle proteins involved in translation initiation. GCN2 therefore acts as a master control switch, regulating global protein synthesis in response to amino acid availability in the cell. The aim of this project was to elucidate components of the GCN2 signalling pathway in wheat. GCN2 cDNA was identified and cloned, the nucleotide and peptide sequence analysis revealed it be a genuine GCN2-like kinase. Under normal nutrient conditions, analysis of expression and abundance revealed wheat GCN2 to exist at steady levels in leaves and under developmental control in grain. Levels of GCN2 increased in response to nitrogen deprivation. In order to further understand the role of GCN2 in wheat, transgenic wheat lines were produced in which GCN2 was either knocke-down by RNAi, or overexpressed. Wheat plants were genetically modified using particle bombardment and grown to the T2 or T3 generation for analysis. Analysis of the grain from transgenic plants revealed altered free amino acid levels, some transgenic plants were found to have an increased yield relative to the controls. The results suggest that TaGCN2 is involved in the link between free amino acid levels and protein synthesis in the grain

Mum or bub? Which influences breastfeeding loyalty

The need for social marketing research in the area of breastfeeding is highlighted by the failure of campaigns to increase breastfeeding rates over the past two decades in developed countries. This is despite evidence of the health benefits of longer breastfeeding duration to both baby and mother, and the high levels of expenditure on these campaigns. Whilst past campaign approaches typically focus on baby-oriented factors, breastfeeding is a complex behaviour that for many women involves barriers that influence their commitment to continued breastfeeding. Using social marketing, this research investigates the role of mother-centred factors on loyalty to breastfeeding. A sample of 405 Australian women completed an online survey. The data were analysed using structural equation modelling, which revealed that mother-oriented, rather than baby-oriented, factors influence attitudinal and behavioural loyalty to breastfeeding