Spin wave dispersion softening in the ferromagnetic Kondo lattice model for manganites

Spin dynamics is calculated in the ferromagnetic (FM) state of the generalized Kondo lattice model taking into account strong on-site correlations between e_g electrons and antiferromagnetic (AFM) exchange among t_{2g} spins. Our study suggests that competing FM double-exchange and AFM super-exchange interaction lead to a rather nontrivial spin-wave spectrum. While spin excitations have a conventional Dq^2 spectrum in the long-wavelength limit, there is a strong deviation from the spin-wave spectrum of the isotropic Heisenberg model close to the zone boundary. The relevance of our results to the experimental data are discussed.Comment: 6 RevTex pages, 3 embedded PostScript figure

On the search of a lost urban planning modernity: throughout the legacy of Lewis Mumford

Starting from the correspondence held by Mumford and Muntañola, the article follows a critical trace developed by the same Muntañola with Saura Carulla, pointing out some key issues faced by Mumford in his vast work. Such issues allow to highlight, among the rest, the very contemporary, innovative and critical strength of the message left by the American Regionalist movement, centered on an integrated and complex relationship among man, nature and technology and a multidisciplinary vision considering planning as a ‘civic’ practice, emphasizing its ‘education’ and communication dimensions. Using the metaphor of “The Egg of the Snake” for the basic theoretical and practical errors of urban planning, the article highlights how Mumford had carefully analyzed such ‘eggs’ over time - a critique of contemporary urban planning in relation to ecological balances and wrong social practices, an analysis of the role of technology in relation to social welfare and so on - and for this had been charged, to his regret, of retrograde attitude. This critical reading of the typical approach to urban project, especially revealed in his last years, shows perhaps a state of anxiety that, in Mumford, was about to flow into a trans-disciplinary approach.Strutturato a partire dalla corrispondenza tenuta da Mumford e Muntañola, l’articolo si sviluppa attraverso una traccia critica svolta dallo stesso Muntañola e da Saura Carulla, cogliendo alcune questioni chiave affrontate da Mumford nella sua vasta opera. I temi individuati consentono di evidenziare fra le altre cose l’attualissima forza innovativa e critica del messaggio del Movimento Regionalista americano, incentrata su di un approccio integrato e complesso della relazione uomo-natura-tecnologia e su una visione multidisciplinare che vede la pianificazione come pratica ‘civica’, sottolineandone la dimensione ‘educativa’ e comunicativa. Utilizzando la metafora dell’“uovo del serpente” per i fondamentali errori teorici e pratici della pianificazione urbana, nell’articolo si evidenzia come Mumford abbia nel tempo analizzato con molta cura queste ‘uova’ - la critica della pianificazione urbana contemporanea in relazione agli equilibri ecologici e a pratiche sociali sbagliate, l’analisi sul ruolo della tecnologia in relazione al benessere sociale ecc. - e sia stato per questo accusato, con suo sommo rammarico, di atteggiamento retrogrado. Questa lettura critica, manifestata soprattutto negli ultimi anni, del modo in cui ci si avvicinava al progetto della città mostra forse uno stato di inquietudine che in Mumford stava sfociando in un approccio interdisciplinare

Real-time monitoring of volatile organic compounds using chemical ionization mass spectroscopy: Final report

Volatile organic compound (VOC) emission to the atmosphere is of great concern to semiconductor manufacturing industries, research laboratories, the public, and regulatory agencies. Some industries are seeking ways to reduce emissions by reducing VOCs at the point of use (or generation). This paper discusses the requirements, design, calibration, and use of a sampling inlet/quadrupole mass spectrometer system for monitoring VOCs in a semiconductor manufacturing production line. The system uses chemical ionization to monitor compounds typically found in the lithography processes used to manufacture semiconductor devices (e.g., acetone, photoresist). The system was designed to be transportable from tool to tool in the production line and to give the operator real-time feedback so the process(es) can be adjusted to minimize VOC emissions. Detection limits ranging from the high ppb range for acetone to the low ppm range fore other lithography chemicals were achieved using chemical ionization mass spectroscopy at a data acquisition rate of approximately 1 mass spectral scan (30 to 200 daltons) per second. A demonstration of exhaust VOC monitoring was performed at a working semiconductor fabrication facility during actual wafer processing

Conceptualising examinable physical education in the Irish context: Leaving Certificate Physical Education

peer-reviewedA Physical Education Development Group (PEDG) was responsible for constructing a new school subject curriculum, Leaving Certificate Physical Education (LCPE), in Ireland. This paper provides an insight into this development group and explores the process of curriculum development, and the influence of roles and power-ratios within the group, in the construction of the LCPE curriculum. Figurational sociology concepts (Elias, 1978) were drawn on to make sense of the curriculum makers’ experiences. Interviews were conducted with 10 PEDG members. The findings suggest that the members’ roles had very little, if any, influence on the curriculum development process. Findings also revolved around the unbalanced power-ratios which existed in the PEDG and highlighted the socially powerful position of ‘strong, well-established’ (in the academic field of curriculum development – participant's words) members and the other members (predominantly representing practicing teachers). We express concern for the role of teachers in the curriculum process and argue that they play a crucial and significant role in the school subject curriculum development process. This paper supports Goodson’s (1983) and Penney’s (2006) conceptualisation of the contested and socially constructed nature of the curriculum development process.peer-reviewe

You Say Bully, I Say Bullied: School Culture and Definitions of Bullying in Two Elementary Schools

Purpose This chapter examines the definitions of bullying used by students and adults in elementary schools and the effects that these definitions had within the broader school culture. Design/methodology/approach I combine interviews with 53 students and 10 adults and over 430 hours of participant observation with fifth grade students at two rural elementary schools. Findings Definitions of bullying held by those in these schools typically differed from those used by researchers. Even when individuals held definitions that were in line with those used by researchers, however, a focus on identifying bullies rather than on behaviors that fit definitions of bullying contributed to a school culture in which negative interactions were normalized and student reports of these behaviors were discouraged. Research limitations/implications This study is limited to two elementary schools in the rural Midwest and cannot be seen as representative of all schools. Support for my findings from other research combined with similar definitions and school cultures in both schools, however, suggest that these definitions and practices are part of a broader cultural context of bullying in the United States. Practical implications These findings suggest that schools might be better served by focusing less on labels like bully and more on particular behaviors that are to be taken seriously by students, teachers, staff members, and principals. Originality/value Although other researchers have studied definitions of bullying, none have combined these definitions with observational data on the broader school contexts in which those definitions are created and used

Enacting the Prevent Duty in Early Childhood Education Settings

This chapter examines the implementation of the Prevent Duty in early childhood education (ECE) provision in England. Findings from a small-scale empirical study suggest that ECE practitioners simultaneously performed, resisted and embodied the requirements of the Prevent Duty in practice. ECE practitioners were performative in their response to the requirement to promote fundamental British values (FBVs) as they evidenced compliance within an environment of regulation. However, ECE practitioners simultaneously operated a pedagogy rich in values education in which children were positioned as constructors of values. The layering of counter-terrorism within safeguarding policy led to a repositioning of practices of surveillance of children and families, which resonates with some critical readings of counter-terrorism policy in ECE