Universal Features of Quantized Thermal Conductance of Carbon Nanotubes

The universal features of quantized thermal conductance of carbon nanotubes (CNTs) are revealed through theoretical analysis based on the Landauer theory of heat transport. The phonon-derived thermal conductance of semiconducting CNTs exhibits a universal quantization in the low temperature limit, independent of the radius or atomic geometry. The temperature dependence follows a single curve given in terms of temperature scaled by the phonon energy gap. The thermal conductance of metallic CNTs has an additional contribution from electronic states, which also exhibits quantized behavior up to room temperature.Comment: 4 pages, 5 figures. accepted for publication in Phys. Rev. Let

Aharonov-Bohm spectral features and coherence lengths in carbon nanotubes

The electronic properties of carbon nanotubes are investigated in the presence of disorder and a magnetic field parallel or perpendicular to the nanotube axis. In the parallel field geometry, the $\phi_{0}(=hc/e)$-periodic metal-insulator transition (MIT) induced in metallic or semiconducting nanotubes is shown to be related to a chirality-dependent shifting of the energy of the van Hove singularities (VHSs). The effect of disorder on this magnetic field-related mechanism is considered with a discussion of mean free paths, localization lengths and magnetic dephasing rate in the context of recent experiments.Comment: 22 pages, 6 Postscript figures. submitted to Phys. Rev.

Access for All?:Sozialinvestitionen in der frühkindlichen Bildung und Betreuung im europäischen Vergleich

Die Investition in kindbezogene Sozialpolitik ist heute ein zentrales Anliegen europäischer Wohlfahrtsstaaten. Frühkindlicher Bildung und Betreuung kommt die Schlüsselrolle zu, Bildungserfolg und Elternerwerbstätigkeit zu fördern zwecks Chancengleichheit und Armutsbekämpfung. Der international verbreitete Sozialinvestitionsdiskurs lenkt leicht davon ab, dass große Unterschiede in den nationalen Systemen frühkindlicher Bildung und Betreuung bestehen, und diese unterschiedlich in die nationalen Wohlfahrtsstaatsregime eingebettet sind. Am Beispiel Schwedens, Deutschlands und Großbritanniens werden verschiedene Kinderbetreuungssysteme einer kritischen Analyse unterzogen mit Hinblick auf ihr „Sozialinvestitionspotenzial“. Die Untersuchung zeigt, dass frühkindliche Bildungsangebote nicht als Allheilmittel zur Vorbeugung sozialer Ungleichheit fungieren können. Falls nicht mit weiteren, auf Gleichheit ausgerichtete Maßnahmen im Bildungs- und sozialen Sicherungsbereich kombiniert, ist zu erwarten, dass sich eine gegenteilige Wirkungslogik der Sozialinvestitionsstrategie entfaltet, die herkunftsbezogene Bildungsungleichheit noch verstärkt.The importance of investing in early childhood is widely acknowledged in policy circles. Particularly formal Early Childhood Education and Care (ECEC) is seen as key to creating equal opportunities and combating poverty by increasing educational achievement of children and supporting parental employment. This social investment perspective has in recent decades supported the rapid development and expansion of ECEC in most European countries. However, the international social investment discourse masks fundamental differences in European ECEC systems and detracts attention from the way ECEC is embedded in the wider welfare regime of a country. This paper critically examines the ‘social investment potential’ of ECEC systems by comparing an early social investment country, Sweden, with two ‘late movers’, the UK and Germany. It argues that investing in ECEC is not per se a panacea for social inclusion. To the contrary, if not combined with other, partly ‘traditional’ equality measures both in education and social protection, ECEC investment may have the opposite effect of increasing social inequality

A rightward shift in the visuospatial attention vector with healthy aging

The study of lateralised visuospatial attention bias in non-clinical samples has revealed a systematic group-level leftward bias (pseudoneglect), possibly as a consequence of right hemisphere dominance for visuospatial attention. Pseudoneglect appears to be modulated by age, with a reduced or even reversed bias typically present in elderly participants. It has been suggested that this shift in bias may arise due to disproportionate aging of the right hemisphere and/or an increase in complementary functional recruitment of the left hemisphere for visuospatial processing. In this study, we report rightward shifts in subjective midpoint judgement relative to healthy young participants whilst elderly participants performed a computerized version of the landmark task (in which they had to judge whether a transection mark appeared closer to the right or left end of a line) on three different line lengths. This manipulation of stimulus properties led to a similar behavioural pattern in both the young and the elderly: a rightward shift in subjective midpoint with decreasing line length, which even resulted in a systematic rightward bias in elderly participants for the shortest line length (1.98° of visual angle). Overall performance precision for the task was lower in the elderly participants regardless of line length, suggesting reduced landmark task discrimination sensitivity with healthy aging. This rightward shift in the attentional vector with healthy aging is likely to result from a reduction in right hemisphere resources/dominance for attentional processing in elderly participants. The significant rightward bias in the elderly for short lines may even suggest a reversal of hemisphere dominance in favour of the left hemisphere/right visual field under specific conditions

Teaching Intercultural Competence in Translator Training

In this position paper we define an interculturally competent translator as one that demonstrates a high level of intercultural knowledge, skills, attitude and flexibility throughout his or her professional engagements. We argue that to attain this goal in translator training intercultural competence needs to be introduced into the curriculum explicitly and in a conceptually clear manner. In this article we provide an overview of earlier attempts at discussing the role of intercultural communication in translator training curricula and we discuss the various pedagogical and practical challenges involved. We also look at some future challenges, identifying increasing societal diversity as both a source of added urgency into intercultural training and a challenge for traditional biculturally based notions of translators’ intercultural competence and we argue for the central role of empathy. Finally, and importantly, we introduce the contributions to the special issue

Plant litter quality affects the accumulation rate, composition, and stability of mineral-associated soil organic matter

Mineral-associated organic matter (MAOM) is a relatively large and stable fraction of soil organic matter (SOM). Plant litters with high rates of mineralization (high quality litters) are hypothesized to promote the accumulation of MAOM with greater efficiency than plant litters with low rates of mineralization (low-quality litters) because litters with high rates of mineralization maximize the synthesis of microbial products and most MAOM is microbial-derived. However, the effect of litter quality on MAOM is inconsistent. We conducted four repeated short-term incubations (46-d each) of four plant litters (alfalfa, oats, maize and soybean) in two low-carbon subsoils (sandy loam and silty loam) with and without nutrient addition. Our short-term incubations focused on the initial stage of litter decompositionduring the time when litter quality has a measureable effect on mineralization rates. Plant litter quality had a much greater effect on litter-C mineralization rate and MAOM-C accumulation than did soil type or nutrient addition. Soils amended with high-quality oat and alfalfa litters had greater MAOM-C accumulation than soils amended with low-quality maize and soybean litters. However, soils amended with high-quality litters also had greater litter-C mineralization than soils amended with low-quality litters. As a result, the accumulation of MAOM-C per unit of litter-C mineralization was lower in soils amended with high-vs. low-quality litters (0.65 vs. 1.39 g MAOM-C accumulated g−1 C mineralized). Cellulose and hemicelluose indices of accumulated MAOM were greater for maize and soybean than oats and alfalfa, however, most carbohydrates in MAOM were plant-derived regardless of litter quality. At the end of the incubations, more of the accumulated MAOM-N was potentially mineralizable in soils amended with high quality litters. Nevertheless, most of the litter-C remained as residual litter; just 12% was mineralized to CO2 and 13% was transferred to MAOM. Our results demonstrate several unexpected effects of litter quality on MAOM stabilization including the direct stabilization of plant-derived carbohydrates

Plant Litter Quality Affects the Accumulation Rate, Composition, and Stability of Mineral-associated Soil Organic Matter

Mineral-associated organic matter (MAOM) is a relatively large and stable fraction of soil organic matter (SOM). Plant litters with high rates of mineralization (high quality litters) are hypothesized to promote the accumulation of MAOM with greater efficiency than plant litters with low rates of mineralization (low-quality litters) because litters with high rates of mineralization maximize the synthesis of microbial products and most MAOM is microbial-derived. However, the effect of litter quality on MAOM is inconsistent. We conducted four repeated short-term incubations (46-d each) of four plant litters (alfalfa, oats, maize and soybean) in two low-carbon subsoils (sandy loam and silty loam) with and without nutrient addition. Our short-term incubations focused on the initial stage of litter decomposition during the time when litter quality has a measureable effect on mineralization rates. Plant litter quality had a much greater effect on litter-C mineralization rate and MAOM-C accumulation than did soil type or nutrient addition. Soils amended with high-quality oat and alfalfa litters had greater MAOM-C accumulation than soils amended with low-quality maize and soybean litters. However, soils amended with high-quality litters also had greater litter-C mineralization than soils amended with low-quality litters. As a result, the accumulation of MAOM-C per unit of litter-C mineralization was lower in soils amended with high-vs. low-quality litters (0.65 vs. 1.39 g MAOM-C accumulated g−1 C mineralized). Cellulose and hemicelluose indices of accumulated MAOM were greater for maize and soybean than oats and alfalfa, however, most carbohydrates in MAOM were plant-derived regardless of litter quality. At the end of the incubations, more of the accumulated MAOM-N was potentially mineralizable in soils amended with high quality litters. Nevertheless, most of the litter-C remained as residual litter; just 12% was mineralized to CO2 and 13% was transferred to MAOM. Our results demonstrate several unexpected effects of litter quality on MAOM stabilization including the direct stabilization of plant-derived carbohydrates

The Public Playground Paradox: "Child’s Joy" or Heterotopia of Fear?

Literature depicts children of the Global North withdrawing from public space to“acceptable islands”. Driven by fears both of and for children, the publicplayground – one such island – provides clear-cut distinctions between childhoodand adulthood. Extending this argument, this paper takes the original approach oftheoretically framing the playground as a heterotopia of deviance, examining –for the first time – three Greek public playground sites in relation to adjacentpublic space. Drawing on an ethnographic study in Athens, findings show fear tounderpin surveillance, control and playground boundary porosity. Normativeclassification as “children’s space” discourages adult engagement. However, in anovel and significant finding, a paradoxical phenomenon sees the playground’spresence simultaneously legitimizing playful behaviour in adjacent public spacefor children and adults. Extended playground play creates alternate orderings andnegotiates norms and hierarchies, suggesting significant wider potential toreconceptualise playground-urban design for an intergenerational public realm