Simple Mean-Field Theory for a Zero-Temperature Fermi Gas at a Feshbach Resonance

We present a simple two-channel mean field theory for a zero-temperature two-component Fermi gas in the neighborhood of a Feshbach resonance. Our results agree with recent experiments on the bare-molecule fraction as a function of magnetic field [Partridge et al., cond-mat/0505353]. Even in this strongly-coupled gas of Li-6, the experimental results depend on the structure of the molecules formed in the Feshbach resonance and, therefore, are not universal.Comment: 4 pages, 1 figure, 27+ references; submitted to PR

The tectonics and mineralisation of the Black Angel Pb/Zn deposit, central west Greenland

The 13.5 M Tonne Black Angel Zn-Pb-A/J-Fe deposit at Marmorilik, West Greenland (71·10' N, 51· 045' W) consists of six massive, strata bound to discordant sulphide lenses hosted in poly-deformed, poly-metamorphosed evaporite bearing carbonates of the Early Proterozoic Upper Marmorilik Formation. This study is an analysis of the tectonics and mineralisation of the orebodies. The research programmed involved detailed and regional structural and stratigraphic mapping, section measuring, extensive underground mapping and sampling, logging of drill cores, detailed mineralogical and textural studies, and stable and lead isotopic analyses. The deposits occur within the Karrat Group supracrustal sequence of the Mid-Proterozoic (1860 -1680 ma. )Rinkian mobile belt, an upper greenschist to granulite facies terrain composed of Archean and Early Proterozoic tectono-stratigraphic units. Four deformation phases have been recognised within the supracrustal of the Marmorilik and Nukavsak Formations. Three penetrative phases have been assigned to the polyphase Rinkian event end are namely, D1 - an early recumbent nappe phase, D2 - a south verging fold and slide phase and D3 - a sinistral sheer event. Peak metamorphic conditions of upper greenschist facies in the mine area were attained after this deformation, which was succeeded by an extensional D4 deformation (Late Precambrian) associated with dolerite dyke intrusion. The mineralisation occurs as folded and boudinage massive sulphide lenses within a narrow, highly deformed. east-west trending mineralised corridor in the Marmorilik Formation carbonates. The ores consist of tectonised, metamorphosed and recrystalised medium to coarse grained sphalerite, galena, pyrite, pyrrhotite and chalcopyrite with subordinate tennantite and arsenopyrite. Primary void-fill (marcasite/early pyrite) textures occur in metamorphic pyrite grains. Intense shearing at the ore host rock contacts has produced discordant relationships and the inclusion of rafted calcites marble and pelitics clasts, quartz eyes and fluorite vein fragments within the sulphides. Ten types of ore tectonites have been recognised and these have been classified, according to their mineralogy and texture, Into four distinct ore facies associations. The ore facies associations are related to particular deformation structures. Those belonging to D1 and D3 are the most significant. D1 produced large ENE-WNW trending recumbent overfolds and thickening of the ore lenses and D3 gave rise to ESE-WNW trending per inclines with substantial ore thickening and remobilisation in the fold hinge regions. Lead isotope analyses on galenas from the deposits end surrounding carbonate hosted mineralisation indicate strongly homogenised ‘orogen' to upper crustal leads. Minor changes in the ore lead source are possible indicated by a bimodal distribution of the data. Stable carbon, oxygen and sulphur isotope analyses on the sulphides and carbonate host material gave homogenised results indicative of a strong metamorphic over print S-isotope geotherm mometry on sphalerite galena pairs gives a temperature of 470 ℃ for the D3 deformation. The geological setting, mineralogical associations and primary textural features of the Black Angel deposit indicates that they were probably formed as stratabound Mississippi Valley Type massive sulphdie ores which were subsequently highly deformed and metamorphosed such that primary depositional, textural and isotopic signatures are no longer preserved

Time for practice; sport and the environment

The sport and environment literature is small, utilises a limited number of theoretical positions and ignores the work on social practice theory developed in other disciplines. The oversights in existing research are often compounded by reference to the broad term of sustainability and the use of case studies from the minority – elite, professional, organisations – in the sport sector. This commentary identifies the need for additional research on the mitigation of sport’s environmental impact using different interpretations of how we define, organise and play sport. Expanding the discussion would allow sport to play a more active role in the fundamental lifestyle changes necessitated by the environmental crisis

Relationship between childhood trauma and paranoia: a study of specificity and underlying theoretical mechanisms

Purpose: While biogenetic theories have traditionally dominated understandings of psychosis, there is now a large body of evidence suggesting a causal relationship between childhood trauma and psychosis. We sought to further study this relationship by adopting a psychotic experience specific approach and applying two of Bradford Hill’s causality criteria, namely specificity and underlying theoretical mechanisms, to the relationship between childhood trauma and paranoia. Method: Chapter 1 was a systematic review and meta-analysis that sought to examine the magnitude of the association between childhood sexual (CSA), physical (CPA) and emotional abuse (CEA) and physical (CPN) or emotional neglect (CEN) and paranoia across community and clinical samples. Chapter 2 is an empirical research study that sought to test whether negative core schema mediated the relationship between childhood trauma and paranoia. Study 1 sought to these relationships within the general population, whereas Study 2 aimed to test these in a clinical sample of people with persecutory delusions. We also sought to pilot a new measure of negative core schema, The Schema Rating Scale (SCIRATS). Correlation and mediation analysis were utilised to test our empirical study hypothesis. Results: Our meta-analysis found small associations between all forms of childhood trauma and paranoia examined, however the magnitude of the association may be somewhat greater for CEA and CPA than for the other forms of childhood we examined and paranoia . In Study 1, we found that negative-self, negative-other and both negative-self and negative-other core schema mediated the relationship between childhood trauma and paranoia. We found similar results when repeating these analyses with the SCIRATS. In Study 2, we found significant associations between childhood trauma and negative-self core schema that remained significant on the SCIRATS. Negative-self and negative-other core schema were also significantly associated with paranoia however, when we repeated this analysis with the SCIRATS, only negative-self core schema remained significant. We found no significant association between childhood trauma and paranoia. Positive initial feedback on the SCIRATS would suggest participants view this as an acceptable measure. Conclusions: Whilst acknowledging the limitations associated with our studies, our findings suggest that while there appears to be a general association between the forms of childhood trauma we examined and paranoia, this relationship may be somewhat greater for CEA and CPA and paranoia. They are consistent with cognitive models of psychosis and suggest that negative core schema may be important underlying mechanisms in the relationship between childhood trauma and paranoia. We make recommendations for future research to further examine the evidence for specificity and recommend that individuals with psychosis should be asked about childhood trauma and that future research should further examine the potential benefits of trauma-informed formulation and psychological therapies targeting negative core schema in reducing paranoia

Developing The Case For Pro-Environmental Practices In Community-Based Association Football In England

This thesis proposes the development of pro-environmental practices within football in order to reduce the sport's environmental impact. While research into the relationship between sport and the environment is growing, it remains largely focused upon the professional, commercial, and spectacular elite sector of sport. Much of the sport and environment literature, and advice provided by sport governing bodies, is written from the perspective that individual-centric models of behaviour are absolute and self-help can achieve desirable outcomes. Instead football should be considered as a social practice and the way to achieve change is to examine the relationships between the elements that contribute towards the creation of that practice. Qualitative methods, comprising interviews and a period of participatory action research, involving the researcher undertaking a consultancy role within a community-based football club, were used to identify the extent of the problems facing such organisations. Collaborative efforts were made to reduce the environmental impact of the club via a range of practical measures. A shortage of resources, both human and financial, an absence of governing body programmes or initiatives to promote the environment, and a lack of control over the facilities used, were identified as barriers to this. This confirms community-based football clubs are beyond the scope of existing pro-environmental behavioural thinking, with little option in the management of their operations other than to follow existing routines. The results illustrate the need for a wider debate on how to develop pro-environmental activity in sport and the experience of the majority of sporting organisations. Community-based football, with its many thousands of facilities, clubs and volunteers that rarely receive promotion in the mass media, can be at the forefront of developing a new approach to tackling environmental issues. This, arguably, offers the greatest challenge, but also potential opportunity, for reducing resource use in the sport and improving the environmental landscape. Drawing on social practice theory the findings from this research support the introduction of 'pro-environmental practices' in football to address the difficulties faced. This questions the existing relationships and interactions in football, and offers reflection for other sports and sectors seeking to alter their own activity

Optical Band Splitting and Electronic Perturbations of the Heme Chromophore in Cytochrome c at Room Temperature Probed by Visible Electronic Circular Dichroism Spectroscopy

AbstractWe have measured the electronic circular dichroism (ECD) of the ferri- and ferro-states of several natural cytochrome c derivatives (horse heart, chicken, bovine, and yeast) and the Y67F mutant of yeast in the region between 300 and 750nm. Thus, we recorded the ECD of the B- and Q-band region as well as the charge-transfer band at ∼695nm. The B-band region of the ferri-state displays a nearly symmetric couplet at the B0-position that overlaps with a couplet 790cm−1 higher in energy, which we assigned to a vibronic side-band transition. For the ferro-state, the couplet is greatly reduced, but still detectable. The B-band region is dominated by a positive Cotton effect at energies lower than B0 that is attributed to a magnetically allowed iron→heme charge-transfer transition as earlier observed for nitrosyl myoglobin and hemoglobin. The Q-band region of the ferri-state is poorly resolved, but displays a pronounced positive signal at higher wavenumbers. This must result from a magnetically allowed transition, possibly from the methionine ligand to the dxy-hole of Fe3+. For the ferro-state, the spectra resolve the vibronic structure of the Qv-band. A more detailed spectral analysis reveals that the positively biased spectrum can be understood as a superposition of asymmetric couplets of split Q0 and Qv-states. Substantial qualitative and quantitative differences between the respective B-state and Q-state ECD spectra of yeast and horse heart cytochrome c can clearly be attributed to the reduced band splitting in the former, which results from a less heterogeneous internal electric field. Finally, we investigated the charge-transfer band at 695nm in the ferri-state spectrum and found that it is composed of at least three bands, which are assignable to different taxonomic substates. The respective subbands differ somewhat with respect to their Kuhn anisotropy ratio and their intensity ratios are different for horse and yeast cytochrome c. Our data therefore suggests different substate populations for these proteins, which is most likely assignable to a structural heterogeneity of the distal Fe-M80 coordination of the heme chromophore

Collective molecule formation in a degenerate Fermi gas via a Feshbach resonance

We model collisionless collective conversion of a degenerate Fermi gas into bosonic molecules via a Feshbach resonance, treating the bosonic molecules as a classical field and seeding the pairing amplitudes with random phases. A dynamical instability of the Fermi sea against association into molecules initiates the conversion. The model qualitatively reproduces several experimental observations {[Regal et al., Nature {\bf 424}, 47 (2003)]}. We predict that the initial temperature of the Fermi gas sets the limit for the efficiency of atom-molecule conversion.Comment: 4 pages, 3 figures, 10+ references, accepted to PR