4,059 research outputs found

    Screen-printed potentiometric Ag/AgCl chloride sensors: Lifetime performance and their use in soil salt measurements

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    Silver – silver chloride electrodes (Ag/AgCl) for the detection of chloride ions were fabricated using thick-film technology. Five different formulations were prepared and chloride responses were investigated over time. Almost identical and near Nernstian responses were observed over the first 162 days with an average chloride sensitivity for all formulations of -51.12 mV ± 0.45 mV per decade change in chloride concentration compared with a value of -50.59 mV ± 0.01 mV over 388 days for the best two formulations. After 6-months continuous immersion in tap water, pastes formulated with a glass binder began to exhibit a loss in sensitivity whilst those formulated from a commercial thick-film dielectric paste remained functional for the best part of a year. This difference in lifetime performance is attributed to the inclusion of proprietary additives in the commercial paste aiding adhesion and minimising AgCl leaching. The mechanical and chemical robustness of these electrodes has been demonstrated through their ability to detect changing levels of chloride when immersed in soil columns. This particular capacity will make them an invaluable tool in the fields of hydrology, agricultural science, soil science and environmental science

    Haemophilus influenzae invasive disease in the United States, 1994-1995: near disappearance of a vaccine-preventable childhood disease.

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    We analyzed national Haemophilus influenzae (Hi) surveillance data from 1994 and 1995 to describe the epidemiology of Hi invasive disease among persons of all ages. Serotype data were available for 376 (56%) of 669 reported Hi cases among children aged 4 years or younger; 184 (49%) were H. influenzae type b (Hib). Among children aged 4 or younger, incidence (per 100,000) of all Hi invasive disease was 1.8 in 1994 and 1.6 (p < 0.05) in 1995. Children aged 5 months or younger had the highest average annual incidence rate of Hib invasive disease (2.2 per 100,000); children aged 6 to 11 months had the next highest rate (1.2 per 100,000)(p < 0.05). Of 181 children with Hib invasive disease whose age in months was known, 85 (47%) were too young (aged 5 months or younger) to have completed a primary series with an Hib-containing vaccine. Of the 83 children with known vaccination status who were eligible to receive a primary series (aged 6 months or older), 52 (63%) were undervaccinated, and the remaining 31 (37%) had completed a primary series in which vaccine failed. Among persons aged 5 years or older with Hi invasive disease, the lowest average annual incidence was among those 20 to 39 years of age (0.15 per 100,000), and the highest was among those aged 80 years or older (2.26 per 100,000). Among persons aged 5 years or older, serotype data were available for 1,372 (71%) of the 1,940 Hi invasive disease cases; 159 (28%) of the 568 Hi cases with known serotype were due to Hib

    Emotions in business-to-business service relationships

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    Emotion in business-to-business service relationships regarding cargo services is explored. The service relationship is characterised by mutual trust and cooperation. Contact is mainly via telephone or e-mail with some face-to-face interactions and participants providing a complex, multi-skilled seamless service. Experience rather than training plays a vital role with long-term service relationships built up and maintained. Emotional sensitivity is acquired partly by experience and a repeat customer base but mainly through a genuine desire to help and get to know others. In contrast to the view of emotional labour bringing managerial control or adverse affects to service staff, the emotion engendered by this work is authentic expression bringing personal satisfaction

    Studies of the Binding Properties of Influenza Hemagglutinin Receptor-Site Mutants

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    AbstractSite-specific mutations have been made in the influenza hemagglutinin (HA) receptor binding site to assess the contribution of individual amino acid residues to receptor recognition. Screening of mutant HAs, expressed using recombinant vaccinia virus-infected cells, for their abilities to bind human erythrocytes indicated that substitutions involving conserved residues Y98F, H183F, and L194A severely restricted binding and that the substitution W153A prevented cell surface expression of HA. Mutation of residues E190 and S228 that are in positions to form hydrogen bonds with the 9-OH of sialic acid appeared to increase erythrocyte binding slightly, as did the substitution G225R. Substitutions of other residues that are directly or indirectly involved in receptor binding, S136T, S136A, Y195F, G225D, and L226P, had intermediate effects on binding between these two extremes. Estimates of changes in receptor binding specificity based on inhibition of binding to erythrocytes by nonimmune horse sera indicated that mutants G225R and L226P, unlike wild-type HA, were not inhibited; Y195F and G225D mutants were, like wild type, inhibited; and erythrocyte binding by mutants S136A, S136T, E190A, and S228G was only partially inhibited. Viruses containing mutant HAs Y98F, S136T, G225D, and S228G that cover the range of erythrocyte binding properties observed were also constructed by transfection. All four transfectant viruses replicated in MDCK cells and embryonated hens' eggs as efficiently as wild-type X-31 virus, although the Y98F mutant virus was unable to agglutinate erythrocytes. Mutant MDCK cells that have reduced levels of cell surface sialic acids were susceptible to infection by S136T, G225D, and S228G transfectant viruses and by wild type but not by the Y98F transfectant virus

    Designing Chatbots for Crises: A Case Study Contrasting Potential and Reality

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    Chatbots are becoming ubiquitous technologies, and their popularity and adoption are rapidly spreading. The potential of chatbots in engaging people with digital services is fully recognised. However, the reputation of this technology with regards to usefulness and real impact remains rather questionable. Studies that evaluate how people perceive and utilise chatbots are generally lacking. During the last Kenyan elections, we deployed a chatbot on Facebook Messenger to help people submit reports of violence and misconduct experienced in the polling stations. Even though the chatbot was visited by more than 3,000 times, there was a clear mismatch between the users’ perception of the technology and its design. In this paper, we analyse the user interactions and content generated through this application and discuss the challenges and directions for designing more effective chatbots

    Geriatric Hip Fracture Quality Initiative

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    Introduction: Multiple studies demonstrate increased morbidity, mortality, and loss of independence after hip fractures in geriatric patients. The 1-year mortality rate after a hip fracture has been estimated at anywhere from 14% to 58%. Hip fractures are one of the most common injuries evaluated by the UNM Orthopedic department. Geriatric hip fracture protocols have shown improved outcomes at many other centers with regard to improved functionality and decreased morbidity. The goal of this initiative is to improve outcomes with regard to length of hospital stay, functionality after surgery, and as a result, decreased morbidity and mortality. Materials/methods: All deaths in the orthopedic department were reviewed and analyzed from June 2009 to July 2019. Deaths were identified from morbidity and mortality submissions and NSQIP data. The geriatric hip fracture protocol was developed and implemented in Fall 2019, with non-critical care patients being primarily admitted to orthopedics, with hospitalist co-management. Specific post-operative and pain order sets were developed for efficiency and improved standard of care. Results: Early results of the newly developed geriatric hip fracture protocol demonstrate decreased length of stay in the hospital and earlier time to surgical intervention. It is too early to determine if morbidity and mortality has seen any decrease, however this can be anticipated with earlier time to surgery and decreased time in the hospital. Conclusions: We identified a need and successfully developed an initiative to improve care for geriatric patients with hip fractures. Implementation of this protocol decreased length of hospital stay as well as time to surgery. The analysis of the effect of this protocol on overall morbidity and mortality is ongoing

    A Multi-telescope Campaign on FRB 121102: Implications for the FRB Population

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    We present results of the coordinated observing campaign that made the first subarcsecond localization of a Fast Radio Burst, FRB 121102. During this campaign, we made the first simultaneous detection of an FRB burst by multiple telescopes: the VLA at 3 GHz and the Arecibo Observatory at 1.4 GHz. Of the nine bursts detected by the Very Large Array at 3 GHz, four had simultaneous observing coverage at other observatories. We use multi-observatory constraints and modeling of bursts seen only at 3 GHz to confirm earlier results showing that burst spectra are not well modeled by a power law. We find that burst spectra are characterized by a ~500 MHz envelope and apparent radio energy as high as 104010^{40} erg. We measure significant changes in the apparent dispersion between bursts that can be attributed to frequency-dependent profiles or some other intrinsic burst structure that adds a systematic error to the estimate of DM by up to 1%. We use FRB 121102 as a prototype of the FRB class to estimate a volumetric birth rate of FRB sources RFRB5x105/NrR_{FRB} \approx 5x10^{-5}/N_r Mpc3^{-3} yr1^{-1}, where NrN_r is the number of bursts per source over its lifetime. This rate is broadly consistent with models of FRBs from young pulsars or magnetars born in superluminous supernovae or long gamma-ray bursts, if the typical FRB repeats on the order of thousands of times during its lifetime.Comment: 17 pages, 7 figures. Submitted to AAS Journal
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