84 research outputs found
A DC magnetic metamaterial
Electromagnetic metamaterials are a class of materials which have been
artificially structured on a subwavelength scale. They are currently the focus
of a great deal of interest because they allow access to previously
unrealisable properties like a negative refractive index. Most metamaterial
designs have so far been based on resonant elements, like split rings, and
research has concentrated on microwave frequencies and above. In this work, we
present the first experimental realisation of a non-resonant metamaterial
designed to operate at zero frequency. Our samples are based on a
recently-proposed template for an anisotropic magnetic metamaterial consisting
of an array of superconducting plates. Magnetometry experiments show a strong,
adjustable diamagnetic response when a field is applied perpendicular to the
plates. We have calculated the corresponding effective permeability, which
agrees well with theoretical predictions. Applications for this metamaterial
may include non-intrusive screening of weak DC magnetic fields.Comment: 6 pages, 3 figure
GABAB receptors regulate extrasynaptic GABAA receptors
Tonic inhibitory GABAA receptor-mediated currents are observed in numerous cell types in the CNS, including thalamocortical neurons of the ventrobasal thalamus, dentate gyrus granule cells, and cerebellar granule cells. Here we show that in rat brain slices, activation of postsynaptic GABAB receptors enhances the magnitude of the tonic GABAA current recorded in these cell types via a pathway involving Gi/o G proteins, adenylate cyclase, and cAMP-dependent protein kinase. Using a combination of pharmacology and knockout mice, we show that this pathway is independent of potassium channels or GABA transporters. Furthermore, the enhancement in tonic current is sufficient to significantly alter the excitability of thalamocortical neurons. These results demonstrate for the first time a postsynaptic crosstalk between GABAB and GABAA receptors.peer-reviewe
Uncompensated claims to fair emission space risk putting Paris Agreement goals out of reach
Addressing questions of equitable contributions to emission reductions is important to facilitate ambitious global action on climate change within the ambit of the Paris Agreement. Several large developing regions with low historical contributions to global warming have a strong moral claim to a large proportion of the remaining carbon budget (RCB). However, this claim needs to be assessed in a context where the RCB consistent with the long-term temperature goal (LTTG) of the Paris Agreement is rapidly diminishing. Here we assess the potential tension between the moral claim to the remaining carbon space by large developing regions with low per capita emissions, and the collective obligation to achieve the goals of the Paris Agreement. Based on scenarios underlying the IPCC's 6th Assessment Report, we construct a suite of scenarios that combine the following elements: (a) two quantifications of a moral claim to the remaining carbon space by South Asia, and Africa, (b) a 'highest possible emission reduction' effort by developed regions (DRs), and (c) a corresponding range for other developing regions (ODR). We find that even the best effort by DRs cannot compensate for a unilateral claim to the remaining carbon space by South Asia and Africa. This would put the LTTG firmly out of reach unless ODRs cede their moral claim to emissions space and, like DRs, pursue highest possible emission reductions, which would also constitute an inequitable outcome. Furthermore, regions such as Latin America would need to provide large-scale negative emissions with potential risks and negative side effects. Our findings raise important questions of perspectives on equity in the context of the Paris Agreement including on the critical importance of climate finance. A failure to provide adequate levels of financial support to compensate large developing regions to emit less than their moral claim will put the Paris Agreement at risk
Uncompensated claims to fair emission space risk putting Paris Agreement goals out of reach
Addressing questions of equitable contributions to emission reductions is important to facilitate ambitious global action on climate change within the ambit of the Paris Agreement. Several large developing regions with low historical contributions to global warming have a strong moral claim to a large proportion of the remaining carbon budget (RCB). However, this claim needs to be assessed in a context where the RCB consistent with the long-term temperature goal (LTTG) of the Paris Agreement is rapidly diminishing. Here we assess the potential tension between the moral claim to the remaining carbon space by large developing regions with low per capita emissions, and the collective obligation to achieve the goals of the Paris Agreement. Based on scenarios underlying the IPCC's 6th Assessment Report, we construct a suite of scenarios that combine the following elements: (a) two quantifications of a moral claim to the remaining carbon space by South Asia, and Africa, (b) a 'highest possible emission reduction' effort by developed regions (DRs), and (c) a corresponding range for other developing regions (ODR). We find that even the best effort by DRs cannot compensate for a unilateral claim to the remaining carbon space by South Asia and Africa. This would put the LTTG firmly out of reach unless ODRs cede their moral claim to emissions space and, like DRs, pursue highest possible emission reductions, which would also constitute an inequitable outcome. Furthermore, regions such as Latin America would need to provide large-scale negative emissions with potential risks and negative side effects. Our findings raise important questions of perspectives on equity in the context of the Paris Agreement including on the critical importance of climate finance. A failure to provide adequate levels of financial support to compensate large developing regions to emit less than their moral claim will put the Paris Agreement at risk
Secure robust carbon dioxide removal policy through credible certification
Carbon Dioxide Removal (CDR) is a key element of any mitigation strategy aiming to achieve the long-term temperature goal of the Paris Agreement, as well as national net-zero and net-negative greenhouse gas emissions targets. For robust CDR policy, the credibility of certification schemes is essential
Climatic risks to adaptive capacity
Does climate change influence if societies will be better or worse equipped to reduce climatic risks in the future? A societyâs adaptive capacity determines whether the potential of adaptation to reduce risks will be realized. Assumptions about the level of adaptive capacity are inherently made when the potential for adaptation to reduce risks in the future and resultant levels of risk are estimated. In this review, we look at the literature on human impacts of climate change through the lens of adaptive capacity. Building on evidence of impacts on financial resources as presented in the Working Group 2 (WG2) report of the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), we here present the methodology behind this review and complement it with an analysis of climatic risks to human resources. Based on our review, we argue that climate change itself adds to adaptation constraints and limits. We show that for more realistic assessments of sectoral climate risks, assumed levels of future adaptive capacity should â and can â be usefully constrained in assessments that rely on expert judgment, and propose avenues for doing so
'I was just gobsmacked': care workers responses to BBC Panoramas 'Undercover care: the abuse exposed': invoking mental states as a means of distancing from abusive practices
This paper draws upon discourse analytic techniques and discursive psychology to examine how care workers build accounts of viewing the BBC Panorama programme âUndercover Care: The Abuse Exposedâ which graphically documented the abuse of people with learning disabilities in a residential care setting. 56 interviews were conducted as part of a project concerning adult safeguarding. The analysis considers how careworkers report their reactions and the interactional strategies they use to construct themselves as shocked and disbelieving and thus, as oppositional to the extreme practices in the programme. Their role as careworkers, and therefore as âinsidersâ of the industry that allowed such abuse to happen, makes matters of stake and agency live issues for this particular group; and constructions of âshockâ and âdisbeliefâ are potential ways for participants to distance themselves from the abuse shown in the programme. More broadly, these data show how the invocation of mental states contributes to the management of other discursive business, namely, that of fending off any association with the aforementioned extreme practices
The implications of policy changes on the uptake of a PMTCT programme in rural Malawi: first three years of experience
Objective: To study how the demand for antenatal care (ANC), HIV testing and hospital delivery was influenced by policy changes among pregnant women in rural Malawi. Design: Retrospective analysis of monthly reports. Setting: Malamulo SDA hospital in Thyolo district, Makwasa, Malawi. Methods: Three hospital-based registers were analysed from 2005 to 2007. These were general ANC, delivery and Prevention of Mother to Child Transmission (PMTCT) registers. Observations were documented regarding the introduction of specific policies and when changes were effected. Descriptive analytical methods were used. Results: The ANC programme reached 4,528 pregnant mothers during the study period. HIV testing among the ANC attendees increased from 52.6 to 98.8% after the introduction of routine (opt-out) HIV testing and 15.6% of them tested positive. After the introduction of free maternity services, ANC attendance increased by 42% and the ratio of hospital deliveries to ANC attendees increased from 0.50:1 to 0.66:1. Of the HIV-tested ANC attendees, 52.6% who tested positive delivered in the hospital and got nevirapine at the time of delivery. Conclusions: Increasing maternity service availability and uptake can increase the coverage of PMTCT programmes. Barriers such as economic constraints that prevent women in poor communities from accessing services can be removed by making maternity services free. However, it is likely, particularly in resource-poor settings, that significant increases in PMTCT coverage among those at risk can only be achieved by substantially increasing uptake of general ANC and delivery services.We thank the Swedish Institute, Sweden for the financial support without which the study would have been a non-starter. We are also grateful for the support given by the unit of Epidemiology and Public Health Sciences, Umea University. Furthermore, we thank the management and staff of Malamulo SDA Hospital, P/Bag 2, Makwasa, Malawi for their support throughout the entire period of carrying out the study. This work was undertaken within the Centre for Global Health at Umea University with support from FAS, the Swedish Council for Working Life and Social Research (grant no. 2006-1512).</p
Wave of net zero emission targets opens window to meeting the Paris Agreement
National net zero emission targets could, if fully implemented, reduce best estimates of projected global average temperature increase to 2.0â2.4â°C by 2100, bringing the Paris Agreement temperature goal within reach. A total of 131 countries are discussing, have announced or have adopted net zero targets, covering 72% of global emissions. These targets could substantially lower projected warming as compared to currently implemented policies (2.9â3.2â°C) or pledges submitted to the Paris Agreement (2.4â2.9â°C)
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