Detection of Atmospheric Cherenkov Radiation Using Solar Heliostat Mirrors

The gamma-ray energy region between 20 and 250 GeV is largely unexplored. Ground-based atmospheric Cherenkov detectors offer a possible way to explore this region, but large Cherenkov photon collection areas are needed to achieve low energy thresholds. This paper discusses the development of a Cherenkov detector using the heliostat mirrors of a solar power plant as the primary collector. As part of this development, we built a prototype detector consisting of four heliostat mirrors and used it to record atmospheric Cherenkov radiation produced in extensive air showers created by cosmic ray particles.Comment: 16 latex pages, 8 postscript figures, uses psfig.sty, to be published in Astroparticle Physic

The STACEE-32 Ground Based Gamma-ray Detector

We describe the design and performance of the Solar Tower Atmospheric Cherenkov Effect Experiment detector in its initial configuration (STACEE-32). STACEE is a new ground-based gamma ray detector using the atmospheric Cherenkov technique. In STACEE, the heliostats of a solar energy research array are used to collect and focus the Cherenkov photons produced in gamma-ray induced air showers. The large Cherenkov photon collection area of STACEE results in a gamma-ray energy threshold below that of previous detectors.Comment: 45 pages, 25 figures, Accepted for publication in Nuclear Instruments and Methods

Very high energy observations of the BL Lac objects 3C 66A and OJ 287

Using the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE), we have observed the BL Lac objects 3C 66A and OJ 287. These are members of the class of low-frequency-peaked BL Lac objects (LBLs) and are two of the three LBLs predicted by Costamante and Ghisellini to be potential sources of very high energy (>100 GeV) gamma-ray emission. The third candidate, BL Lacertae, has recently been detected by the MAGIC collaboration. Our observations have not produced detections; we calculate a 99% CL upper limit of flux from 3C 66A of 0.15 Crab flux units and from OJ 287 our limit is 0.52 Crab. These limits assume a Crab-like energy spectrum with an effective energy threshold of 185 GeV.Comment: 24 pages, 15 figures, Accepted for publication in Astroparticle Physic

Priority setting for adult malnutrition and nutritional screening in healthcare: a James Lind Alliance.

BACKGROUND: Malnutrition is one the greatest global health challenges of our generation, leading to the increased utilisation of healthcare resources, as well as morbidity and mortality. Research has primarily been driven by industry, academia and clinical working groups and has had little involvement from patients and carers. The project described in the present study aimed to establish a priority setting partnership allowing patients, carers and healthcare professionals an opportunity to influence the research agenda. METHODS: A national survey was conducted to gather malnutrition uncertainties and identify key issues (i.e. areas within scope where an evidence-base is lacking) from those with experience of malnutrition. Uncertainties were analysed according to themes. Similar questions were grouped and summary questions were developed. A second survey was conducted and respondents were asked to choose their 10 most important summary questions. A workshop was conducted to finalise the top 10 research priorities from the most frequently indicated uncertainties on the interim survey. RESULTS: Overall, 1128 uncertainty questions were submitted from 268 people. The interim survey had 71 responses and a list of the top 26 questions was generated for the workshop. There were 26 questions discussed, ranked and agreed by healthcare professionals, carers and patients at the workshop. The top 10 research priorities were then chosen. These included questions on oral nutritional supplements, vulnerable groups, screening, community care, use of body mass index and technology. CONCLUSIONS: The top 10 research priorities in malnutrition and nutritional screening have been identified from a robust process involving patients, carers and healthcare professionals

Oxidation of sodium thiocyanate (NaSCN) in high ionic-strength process aqueous liquor

MSc (Chemistry), North-West University, Potchefstroom Campus, 2016The use of liquid redox processes (Stretford Process) for the absorption of H2S from gaseous streams and converting the absorbed H2S into elemental sulphur is widely used. The chemistry of Stretford process aqueous liquors is very complicated and maintaining the critical chemical parameters is imperative. Sodium thiocyanate (NaSCN) is used for bacterial control and for reducing the consumption of sodium anthraquinone 2,7-disulphonate (Na2[ADA]) in Stretford process aqueous liquors. A series of experiments were conducted to investigate the degree of oxidation of NaSCN in aqueous solutions and Stretford process aqueous liquors using oxidants such as hydrogen peroxide (H2O2), air, intermediate H2O2 from sodium ammonium vanadate (SAV) and sodium anthraquinone 2,7-disulphonate (Na2[ADA]). A decrease in the total alkalinity and Na2[ADA] concentration was also observed under these oxidising conditions. Some of the techniques employed during the study were X-ray diffraction (XRD), X-ray fluorescence (XRF), Ion Chromatography (IC), Fourier Transform Infrared (FTIR), automated titration and Gas Chromatography-Mass Spectrometry (GC-MS). The products formed from the oxidations were identified. The FTIR and XRD results confirmed that a mixture of (NaSCN)x and amorphous polymeric (SCN)x was formed as an intermediate when NaSCN solutions were oxidised with H2O2. XRD and XRF results confirmed the presence of Na2SO4 as a major product from the H2O2 oxidation of NaSCN solutions. NaSCN in the Stretford process aqueous liquor is oxidised to form sodium sulphate, burkeite and mascagnite when using air and H2O2. When HCl and NaOH were used at pH values of 7.0 and 9.0 respectively, the concentration of NaSCN remained predominantly unaffected. The oxidation of NaSCN using increased concentrations of Na2[ADA] and SAV did not impact the NaSCN concentration. Small amounts of H2O2 are liberated from Na2[ADA] and SAV during the re-oxidation of Na2[ADA] using SAV. These liberated H2O2 concentrations are not sufficient to facilitate NaSCN oxidation using increased concentrations of these catalysts (i.e. Na2[ADA] and SAV). During oxidation of Stretford process aqueous liquors using air and H2O2, the concentration of NaSCN steadily decreased while the concentration of Na2SO4 increased. During the oxidation of Stretford process aqueous liquor using H2O2, HCN was found to be the main gas liberated. The formation of Na2S2O3 during the oxidation of Stretford process aqueous liquors using H2O2 was not found to be significant since the conditions of increased pH and temperature that facilitate its formation were not met.Master

Strategies to ensure continuity of nutritional care in patients with COVID-19 infection on discharge from hospital: A rapid review

Summary Background & aims The risk of malnutrition in people with COVID-19 is high; prevalence is reported as 37% in general medical inpatients, 53% in elderly inpatients and 67% in ICU. Thus, nutrition is a crucial element of assessment and treatment. This rapid review aimed to evaluate what evidence is available to inform evidence-based decision making on the nutritional care of patients hospitalised with COVID-19 infection. Methods Cochrane Rapid Reviews guidance was followed; the protocol was registered (CRD42020208448). Studies were selected that included patients with COVID-19, pneumonia, respiratory distress syndrome and acute respiratory failure, in hospital or the community, and which examined nutritional support. All types of studies were eligible for inclusion except non-systematic reviews, commentaries, editorials and single case studies. Six electronic databases were searched: MEDLINE, Embase, Cochrane Central Register of Controlled Trials, PubMed, CINAHL and MedRxiv. Results Twenty-six articles on COVID-19 were retrieved, including 11 observational studies, five guidelines and 10 opinion articles. Seven further articles on pneumonia included three RCTs, one unblinded trial, three observational studies, and one systematic review on rehabilitation post-ICU admission for respiratory illness. The evidence from these articles is presented narratively and used to guide the nutritional and dietetic care process. Conclusions Older patients with COVID-19 infection are at risk of malnutrition and addressing this may be important in recovery. The use of nutritional management strategies applicable to other acute conditions are recommended. However, traditional screening and implementation techniques need to be modified to ensure infection control measures can be maintained. The most effective nutritional interventions require further research and more detailed guidance on nutritional management post-discharge to support long-term recovery is needed

Detection of Gamma Rays with E > 100 MeV from BL Lacertae

Original article can be found at: http://www.journals.uchicago.edu/ApJ/--Copyright American Astronomical SocietyPeer reviewe

ESPEN guidelines on nutritional support for polymorbid internal medicine patients

BACKGROUND & AIMS Polymorbidity (also known as multimorbidity) - defined as the co-occurrence of at least two chronic health conditions - is highly prevalent, particularly in the hospitalized population. Nonetheless, clinical guidelines largely address individual diseases and rarely account for polymorbidity. The aim of this project was to develop guidelines on nutritional support for polymorbid patients hospitalized in medical wards. METHODS The methodology used for the development of the current project follows the standard operating procedures for ESPEN guidelines. It started with an initial meeting of the Working Group in January 2015, where twelve key clinical questions were developed that encompassed different aspects of nutritional support: indication, route of feeding, energy and protein requirements, micronutrient requirements, disease-specific nutrients, timing, monitoring and procedure of intervention. Systematic literature searches were conducted in three different databases (Medline, Embase and the Cochrane Library), as well as in secondary sources (e.g. published guidelines), until April 2016. Retrieved abstracts were screened to identify relevant studies that were used to develop recommendations, which were followed by submission to Delphi voting rounds. RESULTS From a total of 4532 retrieved abstracts, 38 relevant studies were analyzed and used to generate a guideline draft that proposed 22 recommendations and four statements. The results of the first online voting showed a strong consensus (agreement of >90%) in 68% of recommendations and 75% of statements, and consensus (agreement of >75-90%) in 32% of recommendations and 25% of statements. At the final consensus conference, a consensus greater than 89% was reached for all of the recommendations. CONCLUSIONS Despite the methodological difficulties in creating non-disease specific guidelines, the evidence behind several important aspects of nutritional support for polymorbid medical inpatients was reviewed and summarized into practical clinical recommendations. Use of these guidelines offer an evidence-based nutritional approach to the polymorbid medical inpatient and may improve their outcomes