324 research outputs found
High magnetic field transport measurement of charge-ordered PrCaMnO strained thin films
We have investigated the magnetic-field-induced phase transition of
charge-ordered (CO) PrCaMnO thin films, deposited onto
(100)-oriented LaAlO and (100)-oriented SrTiO substrates using the
pulsed laser deposition technique, by measuring the transport properties with
magnetic fields up to 22T. The transition to a metallic state is observed on
both substrates by application of a critical magnetic field ( at 60K).
The value of the field required to destroy the charge-ordered insulating state,
lower than the bulk compound, depends on both the substrate and the thickness
of the film. The difference of the critical magnetic field between the films
and the bulk material is explained by the difference of in-plane parameters at
low temperature (below the CO transition). Finally, these results confirm that
the robustness of the CO state, depends mainly on the stress induced by the
difference in the thermal dilatations between the film and the substrate.Comment: 10 pages, 6 figures. To be published in Phys. Rev.
Instability of metal-insulator transition against thermal cycling in phase separated Cr-doped manganites
We show that metal-insulator transition in Pr0.5Ca0.5Mn1-xCrxO3 (x =
0.015-0.025) is unstable against thermal cycling. Insulator-metal transition
shifts down and low temperature resistivity increases each time when the sample
is cycled between a starting temperature TS and a final temperature TF. The
effect is dramatic lower is x. Insulator-metal transition in x = 0.015 can be
completely destroyed by thermal cycling in absence of magnetic field as well as
under H = 2 T. Magnetic measurements suggest that ferromagnetic phase fraction
decreases with thermal cycling. We suggest that increase in strains in
ferromagnetic- charge ordered interface could be a possible origin of the
observed effect.Comment: 14 pages, 5 figures and 2 tables (revised
Religious education for spiritual bricoleurs? the perceptions of students in ten Christian-ethos secondary schools in England and Wales
Religious Education (RE) in England and Wales functions within a post-secular culture. In the last fifty years, approaches characterised by academic rigour, impartiality, and professionalism have been prioritised. In this post-secular culture, the notion of bricolage aptly describes how some young people seek meaning, explore the spiritual dimension of life, with fragmented understandings of, experiences and encounters with the religious traditions.
This paper draws on data from an empirical research project involving 350 students, to explore why students in ten Christian-ethos secondary schools in England and Wales recognised Religious Education (RE) as a significant contributor to their spiritual development. The analysis is illuminated by employing Roebben's (2009) concept of a narthical learning space (NLS) as the lens with which to examine young people’s experiences. Three aspects of RE are explored: the debating of existential questions; opportunities to theologise and reflect; and encounters with the beliefs, practices, and opinions of others.
This article argues that the concept of RE as a narthical learning space alongside the notion of young people as spiritual bricoleurs illuminates how the students in this study interpret the contribution of RE to their spiritual development
Non-linear electrical response in a charge/orbital ordered CaMnO crystal : the charge density wave analogy
Non-linear conduction in a charge-ordered manganese oxide
PrCaMnO is reported. To interpret such a feature, it is
usually proposed that a breakdown of the charge or orbitally ordered state is
induced by the current. The system behaves in such a way that the bias current
may generate metallic paths giving rise to resistivity drop. One can describe
this feature by considering the coexistence of localized and delocalized
electron states with independent paths of conduction. This situation is
reminiscent of what occurs in charge density wave systems where a similar
non-linear conduction is also observed. In the light of recent experimental
results suggesting the development of charge density waves in charge and
orbitally ordered manganese oxides, a phenomenological model for charge density
waves motion is used to describe the non-linear conduction in
PrCaMnO. In such a framework, the non-linear conduction
arises from the motion of the charge density waves condensate which carries a
net electrical current.Comment: 13 pages, 6 figure
Spadin, a Sortilin-Derived Peptide, Targeting Rodent TREK-1 Channels: A New Concept in the Antidepressant Drug Design
We found that spadin, a natural peptide derived from sortilin, blocks the mouse TREK-1 channel and might be an efficient and fast-acting antidepressant
Marriage “sharia style”: everyday practices of Islamic morality in England
The growing visibility of Islam in the public spaces of Western societies is often interpreted in the media as a sign of Muslim radicalisation. This article questions this postulate by examining the flourishing Muslim marriage industry in the UK. It argues that these ‘halal’ services, increasingly popular among the young generation of British Muslims, reflect the semantic shifting of categories away from the repertoire of Islamic jurisprudence to cultural and identity labels visible in public space. Informed by long-term ethnographic fieldwork in the British field of Islamic law, this article examines a Muslim speed-dating event, which took place in central London in 2013. It investigates how Islamic morality is maintained and negotiated in everyday social interactions rather than cultivated via discipline and the pursuit of virtuous dispositions. Using Goffman’s “frame analysis” and his interpretation of the social as a space of “performances” as well as recent anthropological reflections on “ordinary ethics” (Lambek) and “everyday Islam” (Schielke, Osella and Soares), it examines the potential for such practices to define the contours of a new public culture where difference is celebrated as a form of distinction
Anomaly in the dielectric response at the charge orbital ordering transition of crystalline Pr0.67Ca0.33MnO3
The complex impedance of a Pr0.67Ca0.33MnO3 crystal has been measured. The
frequency dependence is studied for a wide range of temperatures (50K-403K) and
is found to be characteristic of relaxation process with a single Debye time
relaxation constant, which is interpreted as a dielectric constant of the
material. A strong peak is observed in this dielectric constant (up to two
millions) at the charge ordering transition suggesting an interpretation in
terms of ordering of electric dipoles at TCO or in term of phase separation.
Comparison with Pr0.63Ca0.37MnO3 - in which the phase separation is much
smaller and the peak in the dielectric constant is absent - suggests an
interpretation in term of phase separation between insulating and metallic
states.Comment: pdf fil
A Human TREK-1/HEK Cell Line: A Highly Efficient Screening Tool for Drug Development in Neurological Diseases
TREK-1 potassium channels are involved in a number of physiopathological processes such as neuroprotection, pain and depression. Molecules able to open or to block these channels can be clinically important. Having a cell model for screening such molecules is of particular interest. Here, we describe the development of the first available cell line that constituvely expresses the TREK-1 channel. The TREK-1 channel expressed by the h-TREK-1/HEK cell line has conserved all its modulation properties. It is opened by stretch, pH, polyunsaturated fatty acids and by the neuroprotective molecule, riluzole and it is blocked by spadin or fluoxetine. We also demonstrate that the h-TREK-1/HEK cell line is protected against ischemia by using the oxygen-glucose deprivation model
Research priorities for grassland science: the need of long term integrated experiments networks
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