1,279 research outputs found
Lead, zinc and copper mineralisation in basal Carboniferous sediments at Westwater, south Scotland
A zioneo f lead, zinc and copperm ineralisatioins developedo ver a minimum
I of 4 km of strikeo f basal Carboniferoucse mentstoneg roup sedimentsa nd
immediatelyu nderlyingB irrenswarkL avas atwestwater,n ear Laqholm in south
Scotland. Grades so far obtained from sparse rock exposures and from shallow
boreholes
a fissure
sulphides
are usuallyO .l-O.j%o f combinedm etals over 1-2 m of thickness,bu t
vein of higher grade and a relativelyt hick zone of disseminated
were also located. Galena, sphalerite,c halcopyritea ndbaryte
occur mainly in thin dolomitev eins but disseminationosf galenaa re also
presenti n sandstoneu nits. The mineralisatioins of low temperaturet ype
I
was emplaceda long northeasterlyt rendingn ormal faultsa nd cross faults
regardeda s late Carboniferouisn age.
and
Mineralisatiohna s been controlledb y faulting,r egionalf aciesv aziation
and local lithologicalv ariationa s well as by stratigraphipco sition. These
controlsa re applicablei n furthere xplorationo f Lower Carboniferourso cks in
both south and central Scotland. The heavy mineral fraction of stream sediment
is the optimums amplingt ype in reconnaissanceex plorationo f areas of calcareous .
rocks such as the Lower Carboniferouso f south Scotlanda nd basal till sampling
is the most effectivem ethod of follow-upe xplorationi n those areas where
glaciald epositsa re widespreada nd often thick
Primary Sequence and Developmental Expression Pattern of mRNAs and Protein for an α1Subunit of the Sodium Pump Cloned from the Neural Plate ofXenopus laevis
AbstractExpression of a catalytic α subunit of the sodium pump was followed in earlyXenopusembryos for correlation with physiological experiments showing that the sodium pump controls cavity expansion and the differentiation of neurones from the neural plate. Two cDNAs (one full length, one partial) for α1subunit isoforms were cloned from a neural plate stageXenopuslibrary and sequenced. Other isoforms were not detected. Temporal and spatial expression patterns for α1subunit transcripts and protein revealed extensive developmental regulation. At all stages, cells involved in cavity generation (outer ectoderm and cells lining the archenteron) expressed α1transcripts with protein confined to the lateral and basal membranes. Before gastrulation, transcript levels were low and predominantly in animal cells. During gastrulation, α1mRNAs rose significantly. Transcripts and protein were down-regulated in future outer neural plate cells as the mesoderm invaginated. Protein appeared at the blastopore on apical surfaces of lip cells and apposing surfaces of invaginating cells, suggesting that the Na pump opposes entry of fluid. In early neurulae, α1mRNAs rose sharply. Transcript expression remained low in outer neural plate cells and increased in the endoderm, and protein appeared in the notochord. In midneurulae, transcripts returned in outer neural plate cells. Protein expression appeared on basal surfaces of deep neural plate cells and the floor plate, matching physiological observations. After neural tube closure, transcripts were detected in all dorsal structures. Protein was retained in the notochord and floor plate, was eliminated from the outer layer of the neural tube, and appeared on ependymal cells. The results are discussed in relation to previous physiological observations
Resonant Raman scattering off neutral quantum dots
Resonant inelastic (Raman) light scattering off neutral GaAs quantum dots
which contain a mean number, N=42, of electron-hole pairs is computed. We find
Raman amplitudes corresponding to strongly collective final states
(charge-density excitations) of similar magnitude as the amplitudes related to
weakly collective or single-particle excitations. As a function of the incident
laser frequency or the magnetic field, they are rapidly varying amplitudes. It
is argued that strong Raman peaks should come out in the spin-density channels,
not related to valence-band mixing effects in the intermediate states.Comment: Accepted in Physical Review
Leveraging sponsorship to achieve consumer relationship objectives through the creation of âmarketing spacesâ: An exploratory study
This paper explores the emergence of sponsorship-linked events as a strategy to leverage relational outcomes through sponsorship investment. The growing use of sponsorship-linked events reinforces the need to understand the potential of such leverage strategies, thus the findings contribute to the body of literature on effective sponsorship practices. Findings from semi-structured interviews with Sponsorship and Marketing Managers suggest a shifting orientation among sponsors towards the pursuit of relational objectives. The privileged access to consumers afforded through sponsorship allows sponsors to manufacture opportunities to create intimacy with customers through sponsorship-linked events in relaxed, comfortable environments; thus sponsorship-linked events are positioned as a rich environment to add value to consumerâbrand interactions and achieve relational objectives. Hosting specifically designed events affords sponsors an increased modicum of control over consumerâbrand experiences in sponsorship environments characterised by a lack of control over sponsored property actions. However, this control may be eroded by social media technologies, which facilitate consumerâconsumer communication around sponsorship-linked events. Social media, however, is proposed as a useful tool to elicit consumer feedback, addressing the misalignment between current sponsorship evaluation practices and emergent relational objectives revealed in the empirical findings. Therefore, successfully activating the sponsorship-linked marketing space demands an integrated and strategic approach
Bacterially mediated removal of phosphorus and cycling of nitrate and sulfate in the waste stream of a "zero-discharge" recirculating mariculture system
Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (~15 mM), were removed by microbial respiration in the sludge resulting in a sulfide accumulation of up to 3 mM. Modelling of the observed S and O isotopic ratios in the surface sludge suggested that, with time, major respiration processes shifted from heterotrophic nitrate and sulfate reduction to autotrophic nitrate reduction. The much higher inorganic P content of the sludge relative to the fish feces is attributed to conversion of organic P to authigenic apatite. This conclusion is supported by: (a) X-ray diffraction analyses, which pointed to an accumulation of a calcium phosphate mineral phase that was different from P phases found in the feces, (b) the calculation that the pore waters of the sludge were highly oversaturated with respect to hydroxyapatite (saturation index = 4.87) and (c) there was a decrease in phosphate (and in the Ca/Na molar ratio) in the pore waters simultaneous with an increase in ammonia showing there had to be an additional P removal process at the same time as the heterotrophic breakdown of organic matter
Reducing car-use for leisure: can organised walking groups switch from car travel to bus and train walks?
This paper deals with the significant leisure travel sector, focusing on the attitudes of organised walking groups towards public transport use. A series of interviews with walking group leaders explored the design of organised walks, and factors affecting journeys to and from start points. The themes presented suggest an overlying group culture involving mainly circular walks, reached by car. The research indicates an underlying engrained dependency on cars to reach walks and a degree of opposition to using public transport, which generally contradicts widelyâheld attitudes towards protecting the environment. Future research should focus more in depth on the long-term removal of psychological barriers to using public transport for leisure, and persuasive measures aimed at groups
T-cell number and subtype influence the disease course of primary chronic lymphocytic leukaemia xenografts in alymphoid mice.
Chronic lymphocytic leukaemia (CLL) cells require microenvironmental support for their proliferation. This can be recapitulated in highly immunocompromised hosts in the presence of T cells and other supporting cells. Current primary CLL xenograft models suffer from limited duration of tumour cell engraftment coupled with gradual T-cell outgrowth. Thus, a greater understanding of the interaction between CLL and T cells could improve their utility. In this study, using two distinct mouse xenograft models, we investigated whether xenografts recapitulate CLL biology, including natural environmental interactions with B-cell receptors and T cells, and whether manipulation of autologous T cells can expand the duration of CLL engraftment. We observed that primary CLL xenografts recapitulated both the tumour phenotype and T-cell repertoire observed in patients and that engraftment was significantly shorter for progressive tumours. A reduction in the number of patient T cells that were injected into the mice to 2-5% of the initial number or specific depletion of CD8+ cells extended the limited xenograft duration of progressive cases to that characteristic of indolent disease. We conclude that manipulation of T cells can enhance current CLL xenograft models and thus expand their utility for investigation of tumour biology and pre-clinical drug assessment
Silician Magnetite: SiâFe-nanoprecipitates and other mineral inclusions in magnetite from the Olympic Dam deposit, South Australia
A comprehensive nanoscale study on magnetite from samples from the outer, weakly mineralized shell at Olympic Dam, South Australia, has been undertaken using atom-scale resolution High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF STEM) imaging and STEM energy-dispersive X-ray spectrometry mapping and spot analysis, supported by STEM simulations. Silician magnetite within these samples is characterized and the significance of nanoscale inclusions in hydrothermal and magmatic magnetite addressed. Silician magnetite, here containing SiâFe-nanoprecipitates and a diverse range of nanomineral inclusions [(ferro)actinolite, diopside and epidote but also U-, W-(Mo), Y-As- and As-S-nanoparticles] appears typical for these samples. We observe both silician magnetite nanoprecipitates with spinel-type structures and a Îł-Feâ.â
SiOâ phase with maghemite structure. These are distinct from one another and occur as bleb-like and nm-wide strips along dâââ in magnetite, respectively. Overprinting of silician magnetite during transition from K-feldspar to sericite is also expressed as abundant lattice-scale defects (twinning, faults) associated with the transformation of nanoprecipitates with spinel structure into maghemite via Fe-vacancy ordering. Such mineral associations are characteristic of early, alkali-calcic alteration in the iron-oxide copper gold (IOCG) system at Olympic Dam. Magmatic magnetite from granite hosting the deposit is quite distinct from silician magnetite and features nanomineral associations of hercynite-ulvöspinel-ilmenite. Silician magnetite has petrogenetic value in defining stages of ore deposit evolution at Olympic Dam and for IOCG systems elsewhere. The new data also add new perspectives into the definition of silician magnetite and its occurrence in ore deposits.Cristiana L. Ciobanu, Max R. Verdugo-Ihl, Ashley Slattery, Nigel J. Cook, Kathy Ehrig, Liam Courtney-Davies, and Benjamin P. Wad
Targeting the Ataxia Telangiectasia Mutated-null Phenotype in Chronic Lymphocytic Leukemia with Pro-oxidants
Inactivation of the Ataxia Telangiectasia Mutated gene in chronic lymphocytic leukemia results in resistance to p53-dependent apoptosis and inferior responses to treatment with DNA damaging agents. Hence, p53-independent strategies are required to target Ataxia
Telangiectasia Mutated-deficient chronic lymphocytic leukemia. As Ataxia Telangiectasia Mutated has been implicated in redox homeostasis, we investigated the effect of the Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia genotype on cellular responses to
oxidative stress with a view to therapeutic targeting. We found that in comparison to Ataxia Telangiectasia Mutated-wild type chronic lymphocytic leukemia, pro-oxidant treatment of Ataxia Telangiectasia Mutated-null cells led to reduced binding of NF-E2 p45-related factor-2 to antioxidant response elements and thus decreased expression of target genes. Furthermore, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia cells contained lower levels of antioxidants and elevated mitochondrial reactive oxygen species. Consequently, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia, but not tumours with 11q deletion or TP53 mutations, exhibited differentially increased sensitivity to pro-oxidants both in vitro and in vivo. We found that cell death was mediated by a p53- and caspase-independent mechanism associated with apoptosis inducing factor activity. Together, these data suggest that defective redox-homeostasis represents an attractive therapeutic target for Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia
Common decisions made and actions taken during small-animal consultations at eight first-opinion practices in the United Kingdom
In order for veterinary surgeons to undertake an evidence-based approach to making decisions about theirpatients, it is important that new evidence is generated to support the clinical decision-making process.Many of the decisions are likely to be around the actions taken to treat or manage health problemsdiscussed during the consultation, and little is currently known about the factors which affect the typeof action taken. The aim of this study was to determine the decisions made and actions taken for healthproblems discussed during first-opinion small-animal consultations, as well as identifying factors whichmay affect the decision-making process.Data were gathered during direct observation of small-animal consultations conducted by 62 veterinarysurgeons in eight first-opinion practices in the United Kingdom. For each patient presented, data weregathered on all health problems discussed during the consultation. The decision made (whether an actionwas taken or not) and the action taken where applicable (e.g. therapeutic treatment with antibiotics) wasalso recorded. A three-level multivariable logistic-regression model was developed, with problem (Level1) nested within patient (Level 2) nested within consulting veterinary surgeon (Level 3), and a binaryoutcome variable of action versus no action.At least one action was taken for 69% (n = 2203/3192) of all problems discussed. Therapeutic treatmentwas the most common action taken (n = 1286/3192 problems; 40.3%), followed by management advice(n = 1040/3192; 32.6%) and diagnostic work-up (n = 323/3192; 10.1%). The most common therapeutictreatment was antibiotics (n = 386/1286; 30%), while the most common management advice given wasdietary advice (n = 509/1040; 48.9%). The three explanatory variables remaining in the final model werewhether the problem was a presenting or non-presenting problem, the type of diagnosis made, andthe body system affected. Explanatory variables which did not remain in the final model were patientsignalment, problem history, consultation type, clinical examination type, and who raised the problem(veterinary surgeon or owner).For over two-thirds of problems discussed, an action was taken which suggests these problems maybe seen as important by the veterinary surgeon and/or pet owner. No action was taken for almost a thirdof cases which could represent âwatchful waitingâ, which has been highlighted as important in humanhealthcare. Future research should focus on the common actions taken, further exploring the complexdecision-making process, and examining the effect of the decisions made on long-term patient outcomes
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