325 research outputs found

    Slower-than-Light Spin-1/2 Particles Endowed with Negative Mass Squared

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    Extending in a straightforward way the standard Dirac theory, we study a quantum mechanical wave-equation describing free spinning particles --which we propose to call "Pseudotachyons" (PT's)-- which behave like tachyons in the momentum space, but like subluminal particles (v<c) in the ordinary space. This is allowed since, as it happens in every quantum theory for spin-1/2 particles, the momentum operator (that is conserved) and the velocity operator (that is not) are independent operators, which refer to independent quantities. As a consequence, at variance with ordinary Dirac particles, for PT's the average velocity is not equal to the classical velocity, but actually to the velocity "dual" of the classical velocity. The speed of PT's is therefore smaller than the speed of light. Since a lot of experimental data seems to involve a negative mass squared for neutrinos, we suggest that these particles might be PT's, travelling, because of their very small mass, at subluminal speeds very close to c. The present theory is shown to be separately invariant under the C, P, T transformations; the covariance under Lorentz transformations is also proved. Furthermore, we derive the kinematical constraints linking 4-impulse, 4-velocity and 4-polarization of free PT'sComment: LaTeX; 20 page

    Materialism and life satisfaction relations between and within people over time: results of a three-wave longitudinal study

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    The negative association between materialism and life satisfaction is well-documented, but it is unclear what the directionality of the association is. To address this issue, we (a) conducted a three-wave longitudinal study (N = 6551) over 3 years and examined the bidirectional relations between life satisfaction and materialism as a composite measure and with each of its three facets (happiness, success, and centrality), and (b) estimated Random Intercept Cross-Lagged Panel Models (RI-CLPMs) that separate inter- and intra-individual effects and compared them with traditional CLPMs that do not. The traditional CLPM showed bidirectional negative associations between composite materialism and life satisfaction and strong negative bidirectional association for the happiness facet, but positive effects of the centrality facet on life satisfaction. However, and importantly, the RI-CLPM revealed that these relations exist predominantly between people. Within people, materialism does not impact life satisfaction, but life satisfaction does impact the happiness facet negatively. These findings challenge common ideas that the direction of the effect is from materialism to life satisfaction and that it is unilaterally negative.info:eu-repo/semantics/publishedVersio

    A qualitative exploration of the experiences of veterans who are serving sentences in custody

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    The focus on veterans in research is not a novel topic; however, the majority of studies are related to trauma, employment, mental health, suicide, and substance misuse. The Criminal Justice System involvement with veterans is a topic that has yet to be examined to a great extent. This study, conducted with adult male prisoners, elicited information from six veterans regarding their experiences of being in the armed forces, leaving the armed forces and becoming involved in the Criminal Justice System. Responses were evaluated using Interpretative Phenomenological Analysis (IPA) and three main themes were identified: “you’re baptised into the army”, ‘them and us,’ and ‘operational mind set’; each of which comprised a number of superordinate themes. The research highlights that, although it is important to acknowledge the heterogenic nature of this group, it is equally important to note that much of their thinking and behaviour may be similar to those that have not had these experiences. As such, there is a need to reduce the notion that they are separate and different to other prisoners, requiring different treatment. The study highlights that many of the Offending Behaviour Programmes and interventions already available to prisoners would be appropriate for this group. The current research supports the merit in creating a service in prisons that will allow for ex-servicemen to meet together and access the support that is available to them. The implications of the research are discussed further

    Preparing isiXhosa home language teachers for the 21st century classroom: Student teachers' experiences, challenges and reflections

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    The aim of the article is to identify the gaps between theory and practice in pre-service teacher training with special reference to the teaching of isiXhosa as a home language in the Further Education and Training (FET) phase (Grades 10–12) in some Western Cape high schools. The article is based on data that was collected from Postgraduate Certificate in Education (PGCE) students taking isiXhosa (home language) as one of their teaching method subjects as part of their pre-service training. The data were collected by means of an open-ended questionnaire, semi-structured interviews and an analysis of student teachers’ reflective journals. The article provides an analysis of PGCE students’ experiences and reflections on the teaching of isiXhosa as a home language in schools. It argues that if there is a gap between theory underpinning initial pre-service training and actual practice in schools, there will be no significant improvement in the teaching of isiXhosa as a home language. It concludes by proposing ways of improving both pre-service and in-service teacher education practice to develop African languages as academic or intellectual languages at school level

    Gold Mining in the Peruvian Amazon: Global Prices, Deforestation, and Mercury Imports

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    Many factors such as poverty, ineffective institutions and environmental regulations may prevent developing countries from managing how natural resources are extracted to meet a strong market demand. Extraction for some resources has reached such proportions that evidence is measurable from space. We present recent evidence of the global demand for a single commodity and the ecosystem destruction resulting from commodity extraction, recorded by satellites for one of the most biodiverse areas of the world. We find that since 2003, recent mining deforestation in Madre de Dios, Peru is increasing nonlinearly alongside a constant annual rate of increase in international gold price (∼18%/yr). We detect that the new pattern of mining deforestation (1915 ha/year, 2006–2009) is outpacing that of nearby settlement deforestation. We show that gold price is linked with exponential increases in Peruvian national mercury imports over time (R2 = 0.93, p = 0.04, 2003–2009). Given the past rates of increase we predict that mercury imports may more than double for 2011 (∼500 t/year). Virtually all of Peru's mercury imports are used in artisanal gold mining. Much of the mining increase is unregulated/artisanal in nature, lacking environmental impact analysis or miner education. As a result, large quantities of mercury are being released into the atmosphere, sediments and waterways. Other developing countries endowed with gold deposits are likely experiencing similar environmental destruction in response to recent record high gold prices. The increasing availability of satellite imagery ought to evoke further studies linking economic variables with land use and cover changes on the ground

    What drives sound symbolism? Different acoustic cues underlie sound-size and sound-shape mappings

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    Sound symbolism refers to the non-arbitrary mappings that exist between phonetic properties of speech sounds and their meaning. Despite there being an extensive literature on the topic, the acoustic features and psychological mechanisms that give rise to sound symbolism are not, as yet, altogether clear. The present study was designed to investigate whether different sets of acoustic cues predict size and shape symbolism, respectively. In two experiments, participants judged whether a given consonant-vowel speech sound was large or small, round or angular, using a size or shape scale. Visual size judgments were predicted by vowel formant F1 in combination with F2, and by vowel duration. Visual shape judgments were, however, predicted by formants F2 and F3. Size and shape symbolism were thus not induced by a common mechanism, but rather were distinctly affected by acoustic properties of speech sounds. These findings portray sound symbolism as a process that is not based merely on broad categorical contrasts, such as round/unround and front/back vowels. Rather, individuals seem to base their sound-symbolic judgments on specific sets of acoustic cues, extracted from speech sounds, which vary across judgment dimensions
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