Pyridoxine and survival of tilapia (Sarotherodon mossambicus Peters)

Pyridoxine requirements of tilapia (Sarotherodon mossambicus Peters) were studied in two separate experiments using casein-based diets. In Experiment 1, fish on pyridoxine supplemented diet (14.0mg/100g diet) showed no adverse symptoms and remained healthy while fish on a pyridoxine-free diet showed abnormal behaviour with high mortality. Graded dietary pyridoxine (0.13 to 3.52mg/100g diet) was used in Experiment 2. Lower dietary supplementations of pyridoxine resulted in reduced weight increase, high mortality, high ratio of serum glutamate-oxal-acetate transaminase glutamate-pyruvate transaminase, and reduced blood sugar. The results suggest the dietary requirement of pyridoxine may be between 0.5g and 1.17mg/100g diet; higher supplementations did not appear to confer any further benefit

Rural property rights and the survival of historic landed estates in the late twentieth century

This thesis examines the evidence for the decline and survival of historic landed estates since the end of the nineteenth century. The focus is on the processes of adaptation undergone by those estates that have survived over the post-war period. These processes are described in this study as a 'compromise' of 'traditional' landed estate characteristics. The particular approach taken by this research is to focus on the manipulation of property rights as a way of comprehending estate survival strategies. The work observes how various forms of legislation and the emergence of other powerful interest groups have acted to increasingly constrain the rights of rural landowners. A conceptual framework indicates how wide-ranging political, economic and social changes, and alterations to family circumstances, are reflected in the changing division and sub-division of owner, occupier and user rights over historic landed estates. The research is based on a micro-level investigation of an estate in south-east Devon. It examines how the political activities of the estate's owners represent attempts made by them to publicise their position and to defend their property rights. Subsequently, the study investigates the evolution of the estate over the post-war period in terms of its ownership and management, size, occupancy, economic activities, and local relations. Particular attention is paid to a series of 'critical' moments when changing circumstances required the formulation of major survival strategies. The study examines the central place of property rights and their accompanying responsibilities, observing how the allocation and re-allocation of property rights has become particularly fluid, complex and contested, and how the manipulation of property rights represents the response of estate owners to both opportunities and threats. The findings of the case study are also considered more broadly, that is, in relation to the position of rural landowners in general in the late twentieth century countrysid

<em>Ab initio</em> thermodynamic model of Cu₂ZnSnS₄

Thin-film solar cells based on the semiconductor Cu2ZnSnS4 (CZTS) are a promising candidate for terawatt-scale renewable energy generation. While CZTS is composed of earth abundant and non-toxic elements, arranged in the kesterite crystal structure, there is a synthetic challenge to produce high-quality stoichiometric materials over large areas. We calculate the thermodynamic potentials of CZTS and its elemental and binary components based on energetic and vibrational data computed using density functional theory. These chemical potentials are combined to produce a thermodynamic model for the stability of CZTS under arbitrary temperatures and pressures, which provide insights into the materials chemistry. CZTS was shown to be thermodynamically stable with respect to its component elements and their major binary phases binaries under modest partial pressures of sulfur and temperatures below 1100 K. Under near-vacuum conditions with sulfur partial pressures below 1 Pa decomposition into binaries including solid SnS becomes favourable, with a strongly temperature-dependent stability window

Two-body correlations and the superfluid fraction for nonuniform systems

We extend the one-body phase function upper bound on the superfluid fraction in a periodic solid (a spatially ordered supersolid) to include two-body phase correlations. The one-body current density is no longer proportional to the gradient of the one-body phase times the one-body density, but rather it depends also on two-body correlation functions. The equations that simultaneously determine the one-body and two-body phase functions require a knowledge of one-, two-, and three-body correlation functions. The approach can also be extended to disordered solids. Fluids, with two-body densities and two-body phase functions that are translationally invariant, cannot take advantage of this additional degree of freedom to lower their energy.Comment: 13 page

Qualitative study of paramedics' experiences of managing seizures: A national perspective from England

Objectives: The UK ambulance service is expected to now manage more patients in the community and avoid unnecessary transportations to hospital emergency departments (ED). Most people it attends who have experienced seizures have established epilepsy, have experienced uncomplicated seizures and so do not require the full facilities of an ED. Despite this, most are transported there. To understand why, we explored paramedics experiences of managing seizures. Design and setting: Semistructured interviews were conducted with a purposive sample of paramedics from the English ambulance service. Interviews were transcribed and thematically analysed. Participants: A diverse sample of 19 professionals was recruited from 5 different ambulance NHS trusts and the College of Paramedics. Results: Participants confirmed how most seizure patients attended to do not clinically require an ED. They explained, however, that a number of factors influence their care decisions and create a momentum for these patients to still be taken. Of particular importance was the lack of access paramedics have to background medical information on patients. This, and the limited seizure training paramedics receive, meant paramedics often cannot interpret with confidence the normality of a seizure presentation and so transport patients out of precaution. The restricted time paramedics are expected to spend on scene due to the way the ambulance services performance is measured and that are few alternative care pathways which can be used for seizure patients also made conveyance likely. Conclusions: Paramedics are working within a system that does not currently facilitate nonconveyance of seizure patients. Organisational, structural, professional and educational factors impact care decisions and means transportation to ED remains the default option. Improving paramedics access to medical histories, their seizure management training and developing performance measures for the service that incentivise care that is cost-effective for all of the health service might reduce unnecessary conveyances to ED

A prova de exercício cárdio-pulmonar e o prognóstico cirúrgico do cancro do pulmão

Resumo: Os autores procuram dar mais um contributo para a avaliação pré-operatória dos doentes com carcinoma de não pequenas células que vão ser sujeitos a cirurgia de ressecção pulmonar.Trata-se de um estudo prospectivo onde foi avaliado o resultado da cirurgia em termos de complicações ocorridas nos 30 dias a seguir à operação. Os autores definiram cada uma das complicações (óbito, enfarte do miocárdio, insuficiências respiratória, cardíaca e renal, embolia pulmonar, pneumonia e septicemia) e ainda analisaram 3 dessas complicações em separado (óbito, enfarte do miocárdio e insuficiência respiratória), as quais designaram por âfraco resultadoâ.Antes da cirurgia, foram avaliados 99 doentes (34 pneumectomias, 56 lobectomias, 6 bilobectomias e 3 ressecções atípicas) com espirometria (FEV1 em litros) e consumo de oxigénio no exercício máximo (VO2peak). Só 26 doentes tinham valores funcionais considerados borderline (FEV1 < 1,5 litros para lobectomia e < 2,0 litros para pneumectomia). Nos resultados apresentados observámos os seguintes valores médios: FEV1=2,06 litros; FEV1=80,4% do valor teórico; VO2peak=18,8 ml/kg/min ou 88,3% do valor teórico. Só existiram 4 óbitos (4%) e 21 doentes tiveram uma ou mais das complicações referenciadas.Os autores não encontraram relação significativa entre as complicações pós-operatórias e o FEV1 em litros. Verificaram ainda que o VO2peak em percentagem do valor teórico previa melhor um âfraco resultadoâ do que o mesmo parâmetro em valor absoluto.Em relação aos óbitos, um dos doentes tinha sido submetido a quimioterapia, o que dificultou a avaliação do desfecho. Nos restantes 3 óbitos, todos os doentes tinham um VO2peak < 62% do valor teórico. Dois dos 3 doentes com VO2peak < 50% tiveram um âfraco resultadoâ. Com VO2peak > 75% só 3 em 20 doentes é que tiveram um âfraco resultadoâ.Apesar de reconhecerem a necessidade de mais e maiores estudos, os autores concluem que VO2peak é importante para prever complicações como óbito, enfarte do miocárdio ou insuficiência respiratória, principalmente se é referido em percentagem do valor teórico. O limite âseguroâ situar-se-ia entre 50 e 60% do valor previsto

Persistent currents in a Bose-Einstein condensate in the presence of disorder

We examine bosonic atoms that are confined in a toroidal, quasi-one-dimensional trap, subjected to a random potential. The resulting inhomogeneous atomic density is smoothened for sufficiently strong, repulsive interatomic interactions. Statistical analysis of our simulations show that the gas supports persistent currents, which become more fragile due to the disorder.Comment: 5 pages, RevTex, 3 figures, revised version, to appear in JLT

Two-level system with a thermally fluctuating transfer matrix element: Application to the problem of DNA charge transfer

Charge transfer along the base-pair stack in DNA is modeled in terms of thermally-assisted tunneling between adjacent base pairs. Central to our approach is the notion that tunneling between fluctuating pairs is rate-limited by the requirement of their optimal alignment. We focus on this aspect of the process by modeling two adjacent base pairs in terms of a classical damped oscillator subject to thermal fluctuations as described by a Fokker-Planck equation. We find that the process is characterized by two time scales, a result that is in accord with experimental findings.Comment: original file is revtex4, 10 pages, three eps figure

Methylthiolate-induced reconstruction of Ag(1 1 1): A medium energy ion scattering study

Medium energy ion scattering (MEIS), using 100 keV H+ incident ions, has been used to investigate the structure of the Ag(1 1 1)(√7 × √7)R19° –CH3S surface phase. The results provide the first direct evidence that this structure does involve substantial reconstruction of the Ag surface layer. The measured absolute scattered ion yields and blocking curves are in generally good agreement with a specific structural model of the surface based on a reconstructed layer containing 3/7 ML Ag atoms, previously suggested on the basis of scanning tunnelling microscopy (STM) and normal incidence X-ray standing wave (NIXSW) studies. However, the MEIS data indicate that any rumpling of the thiolate layer, is small, and probably 0.2 Å. This value is smaller than the amplitude suggested in the STM and NIXSW studies, but could be entirely consistent with the earlier experimental data

Coulomb Effects on Electromagnetic Pair Production in Ultrarelativistic Heavy-Ion Collisions

We discuss the implications of the eikonal amplitude on the pair production probability in ultrarelativistic heavy-ion transits. In this context the Weizs\"acker-Williams method is shown to be exact in the ultrarelativistic limit, irrespective of the produced particles' mass. A new equivalent single-photon distribution is derived which correctly accounts for the Coulomb distortions. As an immediate application, consequences for unitarity violation in photo-dissociation processes in peripheral heavy-ion encounters are discussed.Comment: 13 pages, 4 .eps figure