2,894 research outputs found
Psychopharmacological characterisation of the successive negative contrast effect in rats
Rationale Successive negative contrast (SNC) describes a change in the behaviour of an animal following a downshift in the quantitative or qualitative value of an expected reward. This behavioural response has been hypothesised to be linked to affective state, with negative states associated with larger and/or prolonged shifts in behaviour. Objective This study has investigated whether different psychopharmacological treatments have dissociable actions on the SNC effect in rats and related these findings to their actions on different neurotransmitter systems and affective state. Methods Animals were trained to perform a nose-poke response to obtain a high-value food reward (four pellets). SNC was quantified during devalue sessions in which the reward was reduced to one pellet. Using a within-subject study design, the effects of acute treatment with anxiolytic, anxiogenic, antidepressant and dopaminergic drugs were investigated during both baseline (four pellets) or devalue sessions (one pellet). Results The indirect dopamine agonist, amphetamine, attenuated the SNC effect whilst the D1/D2 antagonist, alpha-flupenthixol, potentiated it. The antidepressant citalopram, anxiolytic buspirone and anxiogenic FG7142 had no specific effects on SNC, although FG7142 induced general impairments at higher doses. The α2-adrenoceptor antagonist, yohimbine, increased premature responding but had no specific effect on SNC. Results for the anxiolytic diazepam were mixed with one group showing an attenuation of the SNC effect whilst the other showed no effect. Conclusions These data suggest that the SNC effect is mediated, at least in part, by dopamine signalling. The SNC effect may also be attenuated by benzodiazepine anxiolytics
Entanglement-free Heisenberg-limited phase estimation
Measurement underpins all quantitative science. A key example is the
measurement of optical phase, used in length metrology and many other
applications. Advances in precision measurement have consistently led to
important scientific discoveries. At the fundamental level, measurement
precision is limited by the number N of quantum resources (such as photons)
that are used. Standard measurement schemes, using each resource independently,
lead to a phase uncertainty that scales as 1/sqrt(N) - known as the standard
quantum limit. However, it has long been conjectured that it should be possible
to achieve a precision limited only by the Heisenberg uncertainty principle,
dramatically improving the scaling to 1/N. It is commonly thought that
achieving this improvement requires the use of exotic quantum entangled states,
such as the NOON state. These states are extremely difficult to generate.
Measurement schemes with counted photons or ions have been performed with N <=
6, but few have surpassed the standard quantum limit and none have shown
Heisenberg-limited scaling. Here we demonstrate experimentally a
Heisenberg-limited phase estimation procedure. We replace entangled input
states with multiple applications of the phase shift on unentangled
single-photon states. We generalize Kitaev's phase estimation algorithm using
adaptive measurement theory to achieve a standard deviation scaling at the
Heisenberg limit. For the largest number of resources used (N = 378), we
estimate an unknown phase with a variance more than 10 dB below the standard
quantum limit; achieving this variance would require more than 4,000 resources
using standard interferometry. Our results represent a drastic reduction in the
complexity of achieving quantum-enhanced measurement precision.Comment: Published in Nature. This is the final versio
Changing homelessness services: revanchism, 'professionalisation' and resistance
This paper argues that the increasing international salience of homelessness can be partially explained by reference to the revanchist thesis (involving processes of coerced exclusion and abjection), but the situation on the ground is more complex. It reports on interviews with 18 representatives of 11 homelessness service providers in one city in England. As Cloke et al. found, these providers tended to be either larger, more 'professional', 'insider' services or smaller, more 'amateur', 'outsider' services. However, this does not mean that the former were necessarily more revanchist and the latter less so. Rather, the actions of both types of organisation could, in some cases, be construed as both advancing and counteracting a revanchist project
Ambiguity in practice? Carers' roles in personalised social care in England
Carers play an ambiguous role within the personalisation paradigm currently shaping adult social care practice in England. Although carers have rights to assessments and support in their own right, these rights sit uneasily alongside the practices of assessment, support planning and personal budget (PB) allocation for older and disabled people. This paper reports how 14 dyads of older and learning disabled people with cognitive and/or communication impairments and their carers viewed the roles - desired and actual - played by carers in PBs. Interviews with carers and with older and disabled people were conducted during 2012 as part of a wider study into carers' roles in assessment, support planning and managing PBs. The interviews complemented a survey of reported practice in two English regions - interviews with adult social care services senior managers and focus groups with front-line care managers. Talking Mats(c) were used to support interviews with some service users. Interviews were transcribed and data analysed using the Framework approach. The interviews indicated that carers played important roles in service users' assessments and support planning, but were less likely to report receiving assessments or support of their own. While carers had the potential to benefit from PBs and support arrangements for service users, this did not reflect practice that aimed to enhance choice and control for carers. The paper draws on Twigg's typology of service conceptualisations of family carers and concludes that, despite the important social rights won by carers in England, current practice continues to regard carers primarily as a resource or a co-worker, rather than a co-client
Using Electronic Technology to Improve Clinical Care -- Results from a Before-after Cluster Trial to Evaluate Assessment and Classification of Sick Children According to Integrated Management of Childhood Illness (IMCI) Protocol in Tanzania.
Poor adherence to the Integrated Management of Childhood Illness (IMCI) protocol reduces the potential impact on under-five morbidity and mortality. Electronic technology could improve adherence; however there are few studies demonstrating the benefits of such technology in a resource-poor settings. This study estimates the impact of electronic technology on adherence to the IMCI protocols as compared to the current paper-based protocols in Tanzania. In four districts in Tanzania, 18 clinics were randomly selected for inclusion. At each site, observers documented critical parts of the clinical assessment of children aged 2 months to 5 years. The first set of observations occurred during examination of children using paper-based IMCI (pIMCI) and the next set of observations occurred during examination using the electronic IMCI (eIMCI). Children were re-examined by an IMCI expert and the diagnoses were compared. A total of 1221 children (671 paper, 550 electronic) were observed. For all ten critical IMCI items included in both systems, adherence to the protocol was greater for eIMCI than for pIMCI. The proportion assessed under pIMCI ranged from 61% to 98% compared to 92% to 100% under eIMCI (p < 0.05 for each of the ten assessment items). Use of electronic systems improved the completeness of assessment of children with acute illness in Tanzania. With the before-after nature of the design, potential for temporal confounding is the primary limitation. However, the data collection for both phases occurred over a short period (one month) and so temporal confounding was expected to be minimal. The results suggest that the use of electronic IMCI protocols can improve the completeness and consistency of clinical assessments and future studies will examine the long-term health and health systems impact of eIMCI
Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection.
Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC) showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+) T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+) T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+) T-cells in PBMC cultures required 'classical' CD14(+) monocytes, which enhanced T-cell activation. CD3(+) T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+) T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease
Lime stabilisation for earthworks: a UK perspective
Lime stabilisation is a versatile technique applied during earthworks operations. Modern soil recycling units are much more efficient at pulverising fill material and intermixing the added binder/water than machinery available 20 years ago. While supplier innovation adds flexibility to the site working method, specifications have not been sufficiently updated to permit optimal application. This review paper details the physico-chemical changes instigated through the lime-clay soil reaction, updating previous reviews. It aims to assist scientific debate, current practitioners and future specification changes. For example, the application of the minimum 24 h mellowing periods (mandatory to UK specifications) with high reactivity, quicklime powders is concluded to cause increased air voids in the compacted fill. Increased air voids are associated with reduced long-term strength and potential volume change from water ingress, which is of particular concern for sulfate swelling. Shorter mellowing periods and/or use of hydrated lime may lesson this issue; however, a 'one size fits all' approach is discouraged in preference to site-specific methodologies refined to suit the fill material and project requirements. The discussion also summarises working methods which may lower the risk of sulfate swell and defines areas requiring further practical research
Rapid generation of chromosome-specific alphoid DNA probes using the polymerase chain reaction
Non-isotopic in situ hybridization of chromosome-specific alphoid DNA probes has become a potent tool in the study of numerical aberrations of specific human chromosomes at all stages of the cell cycle. In this paper, we describe approaches for the rapid generation of such probes using the polymerase chain reaction (PCR), and demonstrate their chromosome specificity by fluorescence in situ hybridization to normal human metaphase spreads and interphase nuclei. Oligonucleotide primers for conserved regions of the alpha satellite monomer were used to generate chromosome-specific DNA probes from somatic hybrid cells containing various human chromosomes, and from DNA libraries from sorted human chromosomes. Oligonucleotide primers for chromosome-specific regions of the alpha satellite monomer were used to generate specific DNA probes for the pericentromeric heterochromatin of human chromosomes 1, 6, 7, 17 and X directly from human genomic DNA
Informing investment to reduce inequalities: a modelling approach
Background: Reducing health inequalities is an important policy objective but there is limited quantitative information about the impact of specific interventions.
Objectives: To provide estimates of the impact of a range of interventions on health and health inequalities.
Materials and methods: Literature reviews were conducted to identify the best evidence linking interventions to mortality and hospital admissions. We examined interventions across the determinants of health: a ‘living wage’; changes to benefits, taxation and employment; active travel; tobacco taxation; smoking cessation, alcohol brief interventions, and weight management services. A model was developed to estimate mortality and years of life lost (YLL) in intervention and comparison populations over a 20-year time period following interventions delivered only in the first year. We estimated changes in inequalities using the relative index of inequality (RII).
Results: Introduction of a ‘living wage’ generated the largest beneficial health impact, with modest reductions in health inequalities. Benefits increases had modest positive impacts on health and health inequalities. Income tax increases had negative impacts on population health but reduced inequalities, while council tax increases worsened both health and health inequalities. Active travel increases had minimally positive effects on population health but widened health inequalities. Increases in employment reduced inequalities only when targeted to the most deprived groups. Tobacco taxation had modestly positive impacts on health but little impact on health inequalities. Alcohol brief interventions had modestly positive impacts on health and health inequalities only when strongly socially targeted, while smoking cessation and weight-reduction programmes had minimal impacts on health and health inequalities even when socially targeted.
Conclusions: Interventions have markedly different effects on mortality, hospitalisations and inequalities. The most effective (and likely cost-effective) interventions for reducing inequalities were regulatory and tax options. Interventions focused on individual agency were much less likely to impact on inequalities, even when targeted at the most deprived communities
Homozygosity for a missense mutation in the 67 kDa isoform of glutamate decarboxylase in a family with autosomal recessive spastic cerebral palsy: parallels with Stiff-Person Syndrome and other movement disorders
Background
Cerebral palsy (CP) is an heterogeneous group of neurological disorders of movement and/or posture, with an estimated incidence of 1 in 1000 live births. Non-progressive forms of symmetrical, spastic CP have been identified, which show a Mendelian autosomal recessive pattern of inheritance. We recently described the mapping of a recessive spastic CP locus to a 5 cM chromosomal region located at 2q24-31.1, in rare consanguineous families.
Methods
Here we present data that refine this locus to a 0.5 cM region, flanked by the microsatellite markers D2S2345 and D2S326. The minimal region contains the candidate gene GAD1, which encodes a glutamate decarboxylase isoform (GAD67), involved in conversion of the amino acid and excitatory neurotransmitter glutamate to the inhibitory neurotransmitter γ-aminobutyric acid (GABA).
Results
A novel amino acid mis-sense mutation in GAD67 was detected, which segregated with CP in affected individuals.
Conclusions
This result is interesting because auto-antibodies to GAD67 and the more widely studied GAD65 homologue encoded by the GAD2 gene, are described in patients with Stiff-Person Syndrome (SPS), epilepsy, cerebellar ataxia and Batten disease. Further investigation seems merited of the possibility that variation in the GAD1 sequence, potentially affecting glutamate/GABA ratios, may underlie this form of spastic CP, given the presence of anti-GAD antibodies in SPS and the recognised excitotoxicity of glutamate in various contexts
- …
