Social and private information influence the decision making of Australian meat ants (Iridomyrmex purpureus)

For social animals, decision-making is influenced by both social information provided by the group, and private information based on the individual’s personal experience. Social insects make excellent study systems for understanding how social and private information is used by individuals to influence their navigational route choice, and thereby influence the collective decision-making strategy of the group. Using colonies of the Australian meat ant, Iridomyrmex purpureus, we demonstrate that when individual workers are trained to a rewarding arm in a Y maze, the trained ants use private information (memory) in route choice when social information (trail pheromone) is experimentally removed and have no preference when private information and social information are in direct conflict with each other. Additional experience did not provide a strong training effect, such that ants returning after their first training trip tended to choose the path they had been trained on (private information) and subsequent trips did not have a significant additional effect on this initial preference

Development of an in vitro periodontal biofilm model for assessing antimicrobial and host modulatory effects of bioactive molecules

Background: Inflammation within the oral cavity occurs due to dysregulation between microbial biofilms and the host response. Understanding how different oral hygiene products influence inflammatory properties is important for the development of new products. Therefore, creation of a robust host-pathogen biofilm platform capable of evaluating novel oral healthcare compounds is an attractive option. We therefore devised a multi-species biofilm co-culture model to evaluate the naturally derived polyphenol resveratrol (RSV) and gold standard chlorhexidine (CHX) with respect to anti-biofilm and anti-inflammatory properties.<p></p> Methods: An in vitro multi-species biofilm containing <i>S. mitis, F. nucleatum, P. Gingivalis</i> and <i>A. Actinomycetemcomitans</i> was created to represent a disease-associated biofilm and the oral epithelial cell in OKF6-TERT2. Cytotoxicity studies were performed using RSV and CHX. Multi-species biofilms were either treated with either molecule, or alternatively epithelial cells were treated with these prior to biofilm co-culture. Biofilm composition was evaluated and inflammatory responses quantified at a transcriptional and protein level.<p></p> Results: CHX was toxic to epithelial cells and multi-species biofilms at concentrations ranging from 0.01-0.2%. RSV did not effect multi-species biofilm composition, but was toxic to epithelial cells at concentrations greater than 0.01%. In co-culture, CHX-treated biofilms resulted in down regulation of the inflammatory chemokine IL-8 at both mRNA and protein level. RSV-treated epithelial cells in co-culture were down-regulated in the release of IL-8 protein, but not mRNA.<p></p> Conclusions: CHX possesses potent bactericidal properties, which may impact downstream inflammatory mediators. RSV does not appear to have bactericidal properties against multi-species biofilms, however it did appear to supress epithelial cells from releasing inflammatory mediators. This study demonstrates the potential to understand the mechanisms by which different oral hygiene products may influence gingival inflammation, thereby validating the use of a biofilm co-culture model.<p></p&gt

Arterial versus venous lactate: a measure of sepsis in children.

This study assessed the agreement between arterial and venous blood lactate and pH levels in children with sepsis. This retrospective, three-year study involved 60 PICU patients, with data collected from electronic or paper patient records. The inclusion criteria comprised of children (≤17 years old) with sepsis and those who had a venous blood gas taken first with an arterial blood gas taken after within one hour. The lactate and pH values measured through each method were analysed. There is close agreement between venous and arterial lactate up to 2 mmol/L. As this value increases, this agreement becomes poor. The limits of agreement (LOA) are too large (±1.90 mmol/L) to allow venous and arterial lactate to be used interchangeably. The mean difference and LOA between both methods would be much smaller if derived using lactate values under 2.0 mmol/L. There is close agreement between arterial and venous pH (MD = -0.056, LOA ± 0.121). However, due to extreme variations in pH readings during sepsis, pH alone is an inadequate marker. CONCLUSION: A venous lactate ≤2 mmol/L can be used as a surrogate for arterial lactate during early management of sepsis in children. However, if the value exceeds 2 mmol/L, an arterial sample must confirm the venous result. What is known: • In children with septic shock, a blood gas is an important test to show the presence of acidosis and high lactic acid. Hyperlactataemia on admission is an early predictor of outcome and is associated with a greater mortality risk. • An arterial sample is the standard for lactate measurement, however getting a sample may be challenging in the emergency department or a general paediatric ward. Venous samples are quicker and easier to obtain. Adult studies generally advise caution in replacing venous lactate values for the arterial standard, whilst paediatric studies are limited in this area. What is new: • This is the first study assessing the agreement between arterial and peripheral venous lactate in children with sepsis, with a significant sample of patients. • This study shows that a venous sample with a lactate of ≤ 2 mmol/L can be used as a surrogate measurement for arterial lactate during early management of sepsis in children. However, if the venous lactate is above 2 mmol/L, an arterial sample must be taken to confirm the result

Improving the use of research evidence in guideline development: 9. Grading evidence and recommendations

BACKGROUND: The World Health Organization (WHO), like many other organisations around the world, has recognised the need to use more rigorous processes to ensure that health care recommendations are informed by the best available research evidence. This is the ninth of a series of 16 reviews that have been prepared as background for advice from the WHO Advisory Committee on Health Research to WHO on how to achieve this. OBJECTIVES: We reviewed the literature on grading evidence and recommendations in guidelines. METHODS: We searched PubMed and three databases of methodological studies for existing systematic reviews and relevant methodological research. We did not conduct a full systematic review ourselves. Our conclusions are based on the available evidence, consideration of what WHO and other organisations are doing and logical arguments. KEY QUESTIONS AND ANSWERS: Should WHO grade the quality of evidence and the strength of recommendations? • Users of recommendations need to know how much confidence they can place in the underlying evidence and the recommendations. The degree of confidence depends on a number of factors and requires complex judgments. These judgments should be made explicitly in WHO recommendations. A systematic and explicit approach to making judgments about the quality of evidence and the strength of recommendations can help to prevent errors, facilitate critical appraisal of these judgments, and can help to improve communication of this information. What criteria should be used to grade evidence and recommendations? • Both the quality of evidence and the strength of recommendations should be graded. The criteria used to grade the strength of recommendations should include the quality of the underlying evidence, but should not be limited to that. • The approach to grading should be one that has wide international support and is suitable for a wide range of different types of recommendations. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, which is currently suggested in the Guidelines for WHO Guidelines, is being used by an increasing number of other organizations internationally. It should be used more consistently by WHO. Further developments of this approach should ensure its wide applicability. Should WHO use the same grading system for all of its recommendations? • Although there are arguments for and against using the same grading system across a wide range of different types of recommendations, WHO should use a uniform grading system to prevent confusion for developers and users of recommendations

The feasibility of collecting information from people with Multiple Sclerosis for the UK MS Register via a web portal: characterising a cohort of people with MS.

BACKGROUND: A UK Register of people with Multiple Sclerosis has been developed to address the need for an increased knowledge-base about MS. The Register is being populated via: a web-based portal; NHS neurology clinical systems; and administrative data sources. The data are de-identified and linked at the individual level. At the outset, it was not known whether people with MS would wish to participate in the UK MS Register by personally contributing their data to the Register via a web-based system. Therefore, the research aim of this work was to build an internet-mounted recruitment and consenting technology for people with Multiple Sclerosis, and to assess its feasibility as a questionnaire delivery platform to contribute data to the UK MS Register, by determining whether the information provided could be used to describe a cohort of people with MS. METHODS: The web portal was developed using VB.net and JQuery with a Microsoft SQL 2008 database. UK adults with MS can self-register and enter data about themselves by completing validated questionnaires. Descriptive statistics were used to characterise the respondents. RESULTS: The web portal was launched in May 2011, and in first three months 7,279 individuals registered on the portal. The ratio of men to women was 1:2.4 (n = 5,899), the mean self-reported age at first symptoms was 33.8 (SD 10.5) years, and at diagnosis 39.6 (SD 10.3) years (n = 4,401). The reported types of MS were: 15% primary progressive, 63% relapsing-remitting, 8% secondary progressive, and 14% unknown (n = 5,400). These characteristics are similar to those of the prevalent MS population. Employment rates, sickness/disability rates, ethnicity and educational qualifications were compared with the general UK population. Information about the respondents' experience of early symptoms and the process of diagnosis, plus living arrangements are also reported. CONCLUSIONS: These initial findings from the MS Register portal demonstrate the feasibility of collecting data about people with MS via a web platform, and show that sufficient information can be gathered to characterise a cohort of people with MS. The innovative design of the UK MS register, bringing together three disparate sources of data, is creating a rich resource for research into this condition

Quantitative effects of tobacco smoking exposure on the maternal-fetal circulation

<p>Abstract</p> <p>Background</p> <p>Despite the existence of various published studies regarding the effects of tobacco smoking on pregnancy, and especially in regards to placental blood flow and vascular resistance, some points still require clarification. In addition, the amount of damage due to tobacco smoking exposure that occurs has not been quantified by objective means. In this study, we looked for a possible association between flow resistance indices of several arteries and the levels of urinary cotinine and the concentration of carbon monoxide in the exhaled air (COex) of both smoking and non-smoking pregnant women. We also looked for a relationship between those findings and fetal growth and birth weight.</p> <p>Methods</p> <p>In a prospective design, thirty pregnant smokers and thirty-four pregnant non-smokers were studied. The volunteers signed consent forms, completed a self-applied questionnaire and were subjected to Doppler velocimetry. Tobacco smoking exposure was quantified by subject provided information and confirmed by the measurement of urinary cotinine levels and by the concentration of carbon monoxide in the exhaled air (COex). The weight of newborns was evaluated immediately after birth.</p> <p>Results</p> <p>Comparing smoking to non-smoking pregnant women, a significant increase in the resistance index was observed in the uterine arteries (P = 0.001) and umbilical artery (P = 0.001), and a decrease in the middle cerebral artery (P = 0.450). These findings were associated with progressively higher concentrations of COex and urinary cotinine. A decrease in the birth weight was also detected (P < 0.001) in association with a progressive increase in the tobacco exposure of the pregnant woman.</p> <p>Conclusions</p> <p>In pregnant women who smoke, higher arterial resistance indices and lower birth weights were observed, and these findings were associated with increasing levels of tobacco smoking exposure. The values were significantly different when compared to those found in non-smoking pregnant women. This study contributes to the findings that smoking damage during pregnancy is dose-dependent, as demonstrated by the objective methods for measuring tobacco smoking exposure.</p

Accreting Black Holes

This chapter provides a general overview of the theory and observations of black holes in the Universe and on their interpretation. We briefly review the black hole classes, accretion disk models, spectral state classification, the AGN classification, and the leading techniques for measuring black hole spins. We also introduce quasi-periodic oscillations, the shadow of black holes, and the observations and the theoretical models of jets.Comment: 41 pages, 18 figures. To appear in "Tutorial Guide to X-ray and Gamma-ray Astronomy: Data Reduction and Analysis" (Ed. C. Bambi, Springer Singapore, 2020). v3: fixed some typos and updated some parts. arXiv admin note: substantial text overlap with arXiv:1711.1025

Foundations of Black Hole Accretion Disk Theory

This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks), Shakura-Sunyaev (thin) disks, slim disks, and advection-dominated accretion flows (ADAFs). After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs).Comment: 91 pages, 23 figures, final published version available at http://www.livingreviews.org/lrr-2013-

Prognostic factors for response to treatment by corticosteroid injection or surgery in carpal tunnel syndrome (PaLMS study): a prospective multi‐centre cohort study

Introduction: Studies of prognosis for surgery and corticosteroid injection for carpal tunnel syndrome have considered only a limited range of explanatory variables for outcome. Methods: Data were prospectively collected on patient‐reported symptoms, physical and psychological functioning, comorbidity and quality of life at baseline and 6 monthly for up to 2 years. Outcomes were patient‐rated change over a 6‐month period and symptom‐severity score at 18 months. Results: 754 patients with CTS completed baseline questionnaires and 626 (83%) completed follow‐up to 18 months. Multivariable modelling identified, independent of symptom severity at outset, higher health utility, fewer comorbidities and lower anxiety as significant predictors of better outcome from surgery. In patients treated by steroid injection, independent of symptom severity at outset, shorter duration of symptoms and having no prior injection were significant predictors of better outcome. Discussion: These multivariable models of outcome may inform shared decision‐making about treatment for CTS

A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source

Most ultraluminous X-ray sources have a typical set of properties not seen in Galactic stellar-mass black holes. They have luminosities of more than 3 × 10 39 ergs per second, unusually soft X-ray components (with a typical temperature of less than about 0.3 kiloelectronvolts) and a characteristic downturn in their spectra above about 5 kiloelectronvolts. Such puzzling properties have been interpreted either as evidence of intermediate-mass black holes or as emission from stellar-mass black holes accreting above their Eddington limit, analogous to some Galactic black holes at peak luminosity. Recently, a very soft X-ray spectrum was observed in a rare and transient stellar-mass black hole. Here we report that the X-ray source P13 in the galaxy NGC 7793 is in a binary system with a period of about 64 days and exhibits all three canonical properties of ultraluminous sources. By modelling the strong optical and ultraviolet modulations arising from X-ray heating of the B9Ia donor star, we constrain the black hole mass to be less than 15 solar masses. Our results demonstrate that in P13, soft thermal emission and spectral curvature are indeed signatures of supercritical accretion. By analogy, ultraluminous X-ray sources with similar X-ray spectra and luminosities of up to a few times 10 40 ergs per second can be explained by supercritical accretion onto massive stellar-mass black holes