Basin bifurcations, oscillatory instability and rate-induced thresholds for AMOC in a global oceanic box model

The Atlantic Meridional Overturning Circulation (AMOC) transports substantial amounts of heat into the North Atlantic sector, and hence is of very high importance in regional climate projections. The AMOC has been observed to show multi-stability across a range of models of different complexity. The simplest models find a bifurcation associated with the AMOC `on' state losing stability that is a saddle node. Here we study a physically derived global oceanic model of Wood {\em et al} with five boxes, that is calibrated to runs of the FAMOUS coupled atmosphere-ocean general circulation model. We find the loss of stability of the `on' state is due to a subcritical Hopf for parameters from both pre-industrial and doubled CO${}_2$ atmospheres. This loss of stability via subcritical Hopf bifurcation has important consequences for the behaviour of the basin of attraction close to bifurcation. We consider various time-dependent profiles of freshwater forcing to the system, and find that rate-induced thresholds for tipping can appear, even for perturbations that do not cross the bifurcation. Understanding how such state transitions occur is important in determining allowable safe climate change mitigation pathways to avoid collapse of the AMOC.Comment: 18 figure

IgE-tailpiece associates with α-1-antitrypsin (A1AT) to protect IgE from proteolysis without compromising its ability to interact with FcεRI

Several splice variants of IgE exist in human plasma, including a variant called IgE-tailpiece (IgE-tp) that differs from classical IgE by the replacement of two carboxy-terminal amino acids with eight novel residues that include an ultimate cysteine. To date, the role of the secreted IgE-tp isoform in human immunity is unknown. We show that levels of IgE-tp are raised in helminth-infected donors, and that both the classical form of IgE (IgE-c) and IgE-tp interact with polymers of the serine protease inhibitor alpha-1-antitrypsin (A1AT). The association of IgE-tp with A1AT polymers in plasma protects the antibody from serine protease-mediated degradation, without affecting the functional interaction of IgE-tp with important receptors, including FcεR1. That polymers of A1AT protect IgE from degradation by helminth proteases may explain why these common and normally non-disease causing polymorphic variants of A1AT have been retained by natural selection. The observation that IgE can be complexed with polymeric forms of A1AT may therefore have important consequences for our understanding of the pathophysiology of pulmonary diseases that arise either as a consequence of A1AT-deficiency or through IgE-mediated type 1 hypersensitivity responses

Implementing emergency department-based HIV testing in a low-resource setting: The value of a structured feasibility assessment tool

Introduction: HIV is a worldwide health problem with continuing high rates of new infections in many parts of the world. This lack of progress in decreasing overall incidence rates has sparked innovative HIV testing strategies, including expansion of testing into the emergency department (ED) setting. Emergency departments have been shown to be high-yield testing venues in the United States and other developed world settings. The feasibility of expanding public health HIV services in the ED in limited-resource countries is unclear.Methods: We performed a cross-sectional feasibility assessment of a convenience sample of four hospitals in the Eastern Cape, South Africa. We administered three adapted interview tools from a previously field-tested survey instrument at each facility (total of 10 interviews) to gather an overview of the health facility, their HIV counselling and testing services, and their laboratory services.Results: All of the health facilities had access to basic commodities such as water and electricity. Many had severe human resource limitations and provided care to wide population catchment areas. In addition, there was little integration of HIV testing into current daily ED operations. Hospital staff identified numerous barriers to future ED testing efforts.Conclusions: Although control of the HIV epidemic requires innovative testing strategies and treatment, specific assessments are warranted on how to incorporate routine HIV testing into an acute care facility like the ED, which typically has many competing priorities. The use of a prospective structured tool incorporating both barriers and benefits can provide valuable field-tested guidance for increased programme planning for HIV testing

Raman Life Detection Instrument Development for Icy Worlds

The objective of this project is to develop a compact, high sensitivity Raman sensor for detection of life signatures in a flow cell configuration to enable bio-exploration and life detection during future mission to our Solar Systems Icy Worlds. The specific project objectives are the following: 1) Develop a Raman spectroscopy liquid analysis sensor for biosignatures; 2) Demonstrate applicability towards a future Enceladus or other Icy Worlds missions; 3) Establish key parameters for integration with the ARC Sample Processor for Life on Icy Worlds (SPLIce); 4) Position ARC for a successful response to upcoming Enceladus or other Icy World mission instrument opportunities

Use of Lysolecithin-Permeabilized Infected-Cell Extracts to Investigate thein VitroBiochemical Phenotypes of Poxvirus ts Mutations Altered in Viral Transcription Activity

AbstractLysolecithin permeabilization of vaccinia virus-infected cells was employed to prepare extracts that support faithful transcription initiationin vitroon plasmids possessing early, intermediate, and late viral gene promoters. Conditions which optimize transcription from each promoter were defined. Thein vitrosystem was used to investigate the multifunctional viral mRNA capping enzyme, which also functions as the viral early gene transcription termination factor (VTF) and a viral intermediate gene transcription initiation factor. A low level of signal-dependent termination of early gene transcription was observedin vitrowhich could be elevated by the addition of pure mRNA capping enzyme. VTF-dependent transcription termination was found to be restricted to templates that possessed an early promoter. This restriction mimics that observedin vivoand demonstrates that transcription termination is limited to RNA polymerase molecules that recognize early rather than intermediate or late gene promoters. Extracts prepared from cells infected at the nonpermissive temperature with a virus containing a ts mutation in gene D12L, which encodes the small subunit of VTF, are incapable of supporting both early gene transcription termination and intermediate gene transcription initiation. Both activities are restored upon addition of the purified wild-type mRNA capping enzyme

Application of Paleoclimatology to Coral Reef Monitoring and Management

The skeletons of reef-building corals are valuable archives of climatic and environmental information. Paleoclimatic data chiefly have been generated in areas most sensitive to global or regional climatic variability. However, these records also provide valuable information on anthropogenic influences – guidance of value to resource managers. NOAA’s Coral Reef Watch targets observations of current and past coral reef health in or near marine protected areas through satellites, in situ sensor platforms, and paleoclimatic analyses. Paleoclimatic data provide retrospective monitoring through multi-century environmental reconstructions that improve our understanding of past stress to coral reefs. Two sites in the Florida Keys National Marine Sanctuary were the first to benefit from Coral Reef Watch Program paleoenvironmental analyses. Coral cores yielded direct measurements of δ18O, δ13C, Sr/Ca, and coral skeletal growth (extension, density, and calcification) and reconstructions of reef temperatures. Temperature reconstructions were compared with instrumental data from nearby stations and global data sets, while skeletal growth was used to infer responses to changing climatic and environmental conditions. Differences between paleoclimatic data and gridded datasets demonstrated that paleodata provide more accurate estimates of reef temperatures as they sample subsurface temperatures where the corals live. Because of relatively high thermal variability, at least 12 samples per year are needed at these sites. Further work will extend these records back in time, to new locations, and expand on the data reconstructed from the skeletal archives

Patient and provider attitudes to emergency department-based HIV counselling and testing in South Africa

Background: The national South African HIV Counselling and Testing (HCT) guidelines mandate that voluntary counselling and testing (VCT) should be offered in all healthcare facilities. Emergency departments (EDs) are at the forefront of many healthcare facilities, yet VCT is not routinely implemented in this setting.Methods: We conducted a cross-sectional study that surveyed patients and healthcare providers at a tertiary care ED in the spring and summer of 2016 to ascertain their attitudes to VCT in the ED. We also used two previously validated survey instruments to gather data on patients’ HIV knowledge and providers’ stigma against patients living with HIV, as we anticipated that these may have an impact on providers’ and patients’ attitudes to the provision of HIV testing within the ED, and may offer insights for future intervention development.Results: A total of 104 patients and 26 providers were enrolled in the study. Overall, patients responded more favourably to ED-based HIV testing (92.3%) compared to providers (only 40% responded favourably). When asked about potential barriers to receiving or providing HIV testing, 16.4% of patients and 24% of providers felt that the subject of HIV was too sensitive and 58.7% of patients and 80% of providers indicated that privacy and confidentiality issues would pose major barriers to implementing ED-based HIV testing.Conclusion: This study shows that while ED-based HIV testing is overall highly acceptable to patients, providers seem less willing to provide this service. The survey data also suggest that future development of ED-based testing strategies should take into consideration privacy and confidentiality concerns that may arise within a busy emergency care setting. Furthermore, every effort should be made to tackle HIV stigma among providers to improve overall attitudes towards HIV-positive individuals that present for care in the ED

Engaging Without Exposing: Use of a Fictional Character to Facilitate Mental Health Talk in Focus Groups With Men Who Have Been Subject to the Criminal Justice System.

In an effort to encourage men with experience of being subject to the criminal justice system to contribute to focus group discussions on the sensitive topic of mental health, while also doing our utmost to protect them from discomfort or risk of exploitation, we used a novel technique involving the creation of a fictional character, supplemented by an audio-recorded vignette. We studied the role played by this technique in achieving our stated aims of "engaging without exposing." In this article, we report on the use of this technique in three focus groups, showing how in very different ways it shaped the interaction between participants and generated crucial insights into the lives and service needs of each group. We conclude that the technique may lend itself to being used in focus groups with other marginalized or seldom-heard populations

Organism/Organic Exposure to Orbital Stresses (OOREOS) Satellite: Radiation Exposure in LEO and Supporting Laboratory Studies

We will present the results from the exposure of the metalloporphyrin iron tetraphenylporphyrin chloride (FeTPPCI), anthraufin (C(sub 14)H(sub 8)(O sub 4) (Anth) and Isoviolanthrene (C(sub 34H sub 18) (IVA) to the outher space environment, measured in situ aboard the Organism/Organic Exposure to Orbital Stresses nanosatellite. The compounds were exposed for a period of 17 months (3700 hours of direct solar exposure) including broad-spectrum solar radiation (approx. 122 nm to the near infrared). The organic films are enclosed in hermetically sealed sample cells that contain one of four astrobiologically relevant microenvironments. Transmission spectra (200-1000 nm) were recorded for each film, at first daily and subsequently every 15 days, along with a solar spectrum and the dark response of the detector array. In addition to analysis via UV-Vis spectroscopy, the laboratory controls were also monitored via infrared and far-UV spectroscopy. The results presented will include the finding that the FeTPPCI and IVA organic films in contact with a humid headspace gas (0.8-2.3%) exhibit faster degradation times, upon irradiation, in comparison with identical films under dry headspaces gases, whereas the Anth thin film exhibited a higher degree of photostability. In the companion laboratory experiments, simulated solar exposure of FeTPI films in contact with either Ar or CO(sub -2):O(sub -2):Ar (10:0.01:1000) headspace gas results in growth of a band in the films infrared spectra at 1961 cm(sup 1). Our assignment of this new spectral feature and the corresponding rational will be presented. The relevance of O/OREOS findings to planetary science, biomarker research, and the photostability of organic materials in astrobiologically relevant environments will also be discussed