1,748 research outputs found
Motivational state and process within the sociolinguistic context : an Anglo-French comparative study of school pupils learning foreign languages
The aim of this study was to investigate the effect of the socio-cultural environment upon the motivation school children have to learn foreign languages. Motivation was therefore considered from a sociolinguistic, rather than from a psycholinguistic perspective, giving primary importance to contextual, as opposed to personal factors. In order to examine the degree of relationship between motivational intensity and the contextual factors of parental attitudes, amount of foreign language exposure and the employment related value of foreign language learning (FLL), data obtained from school children living in two distinct sociolinguistic environments (Mulhouse, France and Walsall, England) were compared and contrasted. A structured sample drawn from pupils attending schools in Mulhouse and Walsall supplied the data base for this research. The main thrust of the study was quantitative in approach, involving the distribution of almost 1000 questionnaires to pupils in both towns. This was followed up by the use of qualitative methods, in the form of in-depth interviews with an individually matched sample of over 50 French/English pupils. The findings of the study indicate that FLL orientations, attitudes and motivation vary considerably between the two sociolinguistic environments. Levels of motivation were generally higher in the French sample than in the English one. Desire to learn foreign languages and a commitment to expend effort in order to fulfil this desire were key components of this motivation. The study also found evidence to suggest that the importance accorded to FLL by the socio-cultural context, communicated to the child through the socialisation agents of the family, the mass media and prospective employers, is of key importance in FLL motivation
Cortisol levels are positively associated with pup-feeding rates in male meerkats
In societies of cooperative vertebrates, individual differences in contributions to offspring care are commonly substantial. Recent attempts to explain the causes of this variation have focused on correlations between contributions to care and the protein hormone prolactin, or the steroid hormone testosterone. However, such studies have seldom considered the importance of other hormones or controlled for non-hormonal factors that are correlative with both individual hormone levels and contributions to care. Using multivariate statistics, we show that hormone levels explain significant variation in contributions to pup-feeding by male meerkats, even after controlling for non-hormonal effects. However, long-term contributions to pup provisioning were significantly and positively correlated with plasma levels of cortisol rather than prolactin, while plasma levels of testosterone were not related to individual patterns of pup-feeding. Furthermore, a playback experiment that used pup begging calls to increase the feeding rates of male helpers gave rise to parallel increases in plasma cortisol levels, whilst prolactin and testosterone levels remained unchanged. Our findings confirm that hormones can explain significant amounts of variation in contributions to offspring feeding, and that cortisol, not prolactin, is the hormone most strongly associated with pup-feeding in cooperative male meerkats
Radio Source Heating in the ICM: The Example of Cygnus A
One of the most promising solutions for the cooling flow problem involves
energy injection from the central AGN. However it is still not clear how
collimated jets can heat the ICM at large scale, and very little is known
concerning the effect of radio lobe expansion as they enter into pressure
equilibrium with the surrounding cluster gas. Cygnus A is one of the best
examples of a nearby powerful radio galaxy for which the synchrotron emitting
plasma and thermal emitting intra-cluster medium can be mapped in fine detail,
and previous observations have inferred possible shock structure at the
location of the cocoon. We use new XMM-Newton observations of Cygnus A, in
combination with deep Chandra observations, to measure the temperature of the
intra-cluster medium around the expanding radio cavities. We investigate how
inflation of the cavities may relate to shock heating of the intra-cluster gas,
and whether such a mechanism is sufficient to provide enough energy to offset
cooling to the extent observed.Comment: To appear in the Proceedings of "Heating vs. Cooling in Galaxies and
Clusters of Galaxies", August 2006, Garching (Germany), Eds. H. Boehringer,
G.W. Pratt, A. Finoguenov, P. Schuecker, Springer-Verlag series "ESO
Astrophysics Symposia", p.101, in press. 8 pages, 3 multiple figure
Multiplicity in Supersymmetric Spin Chains
We discuss a simple procedure for obtaining new integrable spin chains from
old by replacing each single state of the original model by some collection of
states. This works whenever the Lax matrix of the chain has a certain form. The
simplest example is the su(n) XX model. We apply the techniques of the nested
algebraic Bethe ansatz to solve such systems, in the bosonic and supersymmetric
cases.Comment: 14 pages. v2: Added references and minor corrections; v3:
Acknowledgement adde
Constitutive Activation of STAT5A Promotes Human Hematopoietic Stem Cell Self-Renewal and Erythroid Differentiation
Activation of the transcription factor signal transducer and activator of transcription (STAT)5 is involved in various aspects of hematopoiesis, affecting cell proliferation, differentiation, and cell survival. Constitutive activation of STAT5 has also been associated with leukemic transformation. We overexpressed the constitutively active mutant STAT5A(1*6) in human cord blood CD34+ cells and evaluated the effects on the hematopoietic potential of stem cells in a variety of in vitro and in vivo systems. The observed phenotypic changes were correlated with differential gene expression patterns induced by STAT5A(1*6). Our data indicate that a persistent activation of STAT5A in human hematopoietic stem and progenitor cells results in their enhanced self-renewal and diverts differentiation to the erythroid lineage
Automated Telemetric Irrigation Controller
An electronic, microprocessor-based controller was developed
and tested for automating surface irrigation systems. Communication
between the central controller and individual satellite field stations
is by tone telemetry over a single 3-conductor wire. The reliable Dual
Tone Multiple Frequency or Touch Tone system is the same as that used in
telephone communications. The system is designed to actuate momentarily
energized pilot valves commonly used in automated surface irrigation
systems. Because of its low power requirement, the control system can
be battery-powered. It is being field tested in three different, automated
surface systems
Spring-Operated Semi-automatic Irrigation Valves
TORSION spring operators for standard low pressure
butterfly type irrigation valves are described. These
are used with 24-h timers to semiautomate gated pipe
irrigation systems and are particularly well suited for use
with flow-thru single pipeline systems. They are presently
marketed in 150 mm (6 in.), 200 mm (8 in.) and 250 mm
(10 in.) diameter sizes
Conformal Sigma-Models on Supercoset Targets
We investigate the quantum behaviour of sigma models on coset superspaces G/H
defined by Z_{2n} gradings of G. We find that, whenever G has vanishing Killing
form, there is a choice of WZ term which renders the model quantum conformal,
at least to one loop. The choice coincides with that for which the model is
known to be classically integrable. This generalizes results for models
associated to Z_4 gradings, including IIB superstrings in AdS_5\times S^5.Comment: 16 pages, corrected footnote 4 and minor typos, added reference
Quantum Gambling Using Two Nonorthogonal States
We give a (remote) quantum gambling scheme that makes use of the fact that
quantum nonorthogonal states cannot be distinguished with certainty. In the
proposed scheme, two participants Alice and Bob can be regarded as playing a
game of making guesses on identities of quantum states that are in one of two
given nonorthogonal states: if Bob makes a correct (an incorrect) guess on the
identity of a quantum state that Alice has sent, he wins (loses). It is shown
that the proposed scheme is secure against the nonentanglement attack. It can
also be shown heuristically that the scheme is secure in the case of the
entanglement attack.Comment: no essential correction, 4 pages, RevTe
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