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Metabolites produced by microbial fermentation in the human intestine, especially short-chain fatty acids (SCFAs), are known to play important roles in colonic and systemic health. Our aim here was to advance our understanding of how and why their concentrations and proportions vary between individuals. We have analysed faecal concentrations of microbial fermentation acids from 10 human volunteer studies, involving 163 subjects, conducted at the Rowett Institute, Aberdeen, UK over a 7-year period. In baseline samples, the % butyrate was significantly higher, whilst % iso-butyrate and % iso-valerate were significantly lower, with increasing total SCFA concentration. The decreasing proportions of iso-butyrate and iso-valerate, derived from amino acid fermentation, suggest that fibre intake was mainly responsible for increased SCFA concentrations. We propose that the increase in % butyrate among faecal SCFA is largely driven by a decrease in colonic pH resulting from higher SCFA concentrations. Consistent with this, both total SCFA and % butyrate increased significantly with decreasing pH across five studies for which faecal pH measurements were available. Colonic pH influences butyrate production through altering the stoichiometry of butyrate formation by butyrate-producing species, resulting in increased acetate uptake and butyrate formation, and facilitating increased relative abundance of butyrate-producing species (notably Roseburia and Eubacterium rectale).
Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
Introduction: Recent evidence shows an increase in alcohol-related emergency department (ED) visits among youth. Highly publicized collegiate rituals such as Homecoming may create a climate for problematic alcohol use. This study describes the frequency of youth alcohol-related ED visits per year and during pre-specified ritualized drinking dates in one academic centre. Methods: This was a chart review of patients aged 12-24 with alcohol-related ED presentations between Sept 2013-Aug 2017. The National Ambulatory Care Reporting System (NACRS) database was searched for visits with ICD-10 codes related to alcohol. The Canadian Hospital Injury Reporting and Prevention Program (CHIRPP) database was also searched using the keyword alcohol. Duplicate visits were removed. Visits were excluded if patients had a history of psychosis, were held in the ED for involuntary psychiatric assessment, were homeless, were inmates from a correctional institute, if alcohol use was not mentioned and for complaints of sexual assault/domestic violence. Data abstraction by two reviewers used a standard form with variables predetermined. Differences were resolved with third party adjudication. Interrater reliability of the reviewers was assessed through duplicate review of 10% of randomly selected charts. A further 10% were assessed by a 3rd reviewer for extraction accuracy. Results: A total of 3,256 ED visits were identified with 777 meeting exclusion criteria. The remaining 2,479 visits were reviewed and subclassified into injury (51.8%), acute intoxication (45.1%) and mental health issue (3.2%). Interrater agreement was high for extracted variables with Kappa scores > 0.8. Despite a decrease in the region's youth population during the study period (28,325 to 25,125), overall standardized ED visits by youth increased by 12% (66,538 to 78,129). Adjusted for population, youth alcohol-related visits increased by 86.4% from 1,557 in 2013-14 to 2,902 in 2016-17. Co-ingestion of other substances was reported in 292 (11.8%) of visits, with cannabis the most common (57%). The 17 pre-specified ritualized days saw 578 (23.3%) of ED visits. Conclusion: Alcohol-related ED visits in youth are increasing in our region. Ritualized drinking dates appear to be particularly risky for youth with high rates of observed ED utilization. Strategies to manage high volume ritual days are being piloted, including temporary diversion to an in-hospital sobriety centre.
Introduction: Recent evidence shows an increase in alcohol-related emergency department (ED) visits among youth. We sought to quantify the impact of ED visits (type and frequency, patient characteristics and resource use) related to alcohol in our centre. Methods: This was a chart review of patients aged 12-24 with alcohol-related ED visits between Sept 2013-Aug 2017. The National Ambulatory Care Reporting System (NACRS) database was searched for visits alcohol related ICD-10 codes. The Canadian Hospital Injury Reporting and Prevention Program (CHIRPP) database was also searched using the keyword alcohol. Duplicate visits were removed. Visits were excluded if patients had a history of psychosis, were held in the ED for psychiatric assessment, were homeless, were inmates from a correctional institute, if alcohol use was not mentioned and for complaints of sexual assault/intimate partner violence. Data was abstracted by two reviewers using a standard form with predetermined variables. Differences were resolved with third party adjudication. Interrater reliability of the reviewers was assessed with Kappa scores through duplicate review of 10% of randomly selected charts. A further 10% were assessed by a 3rd reviewer for extraction accuracy. Results: 3,256 ED visits were identified with 777 removed via predefined exclusion criteria. 2,479 visits were reviewed with a male predominance (54.3%). More than half of all patients (50.9%) arrived via ambulance. Assigned CTAS levels were Resuscitation: 1% Emergent: 9.9% Urgent: 48.2% Less Urgent: 35.7% Non-Urgent: 4.2% (missing 1%). The median LOS was 2.9 hrs (IQR 1.8-4.6). All visits were subclassified into mutually exclusive categories: injury (51.8%), acute intoxication (45.1%) and mental health issue (3.2%). Males were more likely to present with injury (62.4% vs 42.6%, p < 0.01). Females were more likely to present with acute intoxication (53.3% vs 46.7%, p <0.01) and mental health issues (59.5% vs 40.5%, P = 0.01). ED resource use was notable: 483 (19.4%) had imaging tests and 1216 (49.1%) had some medical intervention (blood test, fluids or medication). 57 (2.3%) patients were admitted and there was one death from an alcohol related MVC. Conclusion: Alcohol-related ED visits by youth are common in our centre and utilize substantial prehospital and in-hospital resources. Identification of effective harm reduction strategies should be a research priority.
Ion imaging by SIMS (ion microprobe) techniques provides a novel approach to the identification of mechanisms of fluid-mineral interaction during hydrothermal experiments. In scanning ion imaging, the primary ion beam is focussed to a fine spot which is rastered across the polished sample surface, and the secondary ion signal from the mass spectrometer is synchronised with the primary beam. The resistive anode encoder provides a direct ion image of a sample surface illuminated by a defocussed primary beam. The latter system is susceptible to charging artifacts during the imaging of insulating geological materials, and has a lower dynamic range than the scanning ion imaging system.
Application of both systems to the study of fluid–mineral interaction during hydrothermal experiments are reviewed in which fluid or solid phases have been labelled with 18O-enriched isotopic tracers. These include studies of micropermeability and microporosity in feldspars, solid-state diffusion versus solution-reprecipitation, textural equilibration mechanisms, and oxygen isotope exchange in silicate–carbonate systems.
A technique based on the relationship between leaf area index (LAI) and the transmittance of direct sunlight was developed for the in situ study of competition for light between plant species. Field studies were conducted in 1984 and 1985 using monocultures and mixtures of rapeseed (Brassica napus L.), wild mustard (Sinapis arvensis L. # SINAR), and common lambsquarters (Chenopodium album L. # CHEAL). LAI estimated nondestructively by this method agreed closely with LAI determined by conventional destructive techniques. Light measurements at several heights in the canopy were used to determine the vertical distribution of canopy leaf area. Combining this information with species heights allowed the separation of the canopy LAI into individual species LAI, from which light competition could be estimated by calculating the sunlit LAI of each species. The technique permits many detailed measurements in the same canopy throughout the growing season. The light sensor required is not costly and is simple to operate and to maintain.
Web-based interventions for depression have burgeoned over the past 10 years as researchers and health professionals aim to harness the reach and cost-effectiveness that the internet promises. Despite strong clinical evidence of their effectiveness and policy support, web-based interventions have not become widely used in practice. We explored this translation gap by conducting an implementation pilot of MindBalance, a web-based intervention for depression built on the SilverCloud platform, in three IAPT services. We posed three questions: (1) Who chooses to use MindBalance? (2) Is MindBalance effective for these clients? (3) How do clients use MindBalance? Our results for questions (1) and (2) are commensurate with the positive findings in the literature on patient acceptability and clinical effectiveness for such interventions. Client usage, captured in adherence data as well as usage case-studies, was diverse and differed markedly from face-to-face sessions. The most surprising result, however, concerned the small number of people who were offered the intervention. We reflect upon why this was and discuss implementation issues that primary mental health services should consider when adding a web-based intervention to their services.
The application of the Rietveld method to quantify mineral components of bauxite and lateritic samples was carried out in order to determine the ability of the method to obtain accurate mineralogical abundances for these materials. The method was initially applied to synthetic mixtures using both Cu and Co Kα radiations, and it was shown that Rietveld-derived data compared favourably with the weighed compositions. Application to two types of natural bauxite resulted in a high correlation between Rietveld predicted values and those calculated by proportioning peak intensities with chemical assays. The use of the whole pattern rather than selected peak intensities gives greater accuracy, confirmed by a strong correlation between derived oxide concentrations from XRF assays. Accuracy and precision were improved by the determination of isomorphous substitution of aluminum in goethite and hematite by refinement of unit cell dimensions. Importantly, the ability of the Rietveld program to successfully model several goethites with different levels of isomorphous substitution improved the correlation between predicted and calculated values. In addition, crystallinity and crystallite size that influence the reactivity of the mineral components can be derived from refined peak profiles.
The adhesion of single podia of Asterias rubens (Echinodermata) was tested under different conditions in order to determine those factors which have an effect on the adhesive forces. In common with many other marine organisms, the adhesion of the podia is sensitive to surface properties of the substratum. The effect of immersion and emersion on tenacity (force per unit area) has been tested. Working with the asteroids completely immersed in sea-water appears to be the best technique to measure the adhesive forces of the podia. The mean tenacity of the podia of A. rubens on glass underwater is 1·98×105 Nm−2.
The measurement of the adhesion strength of marine invertebrates and of its variation under different conditions may give clues to how marine bioadhesives function. Adhesive forces have usually been measured in invertebrates using either permanent or transitory adhesion, but only rarely recorded in animals using temporary adhesion (for review see Walker, 1987).
Of all macrobenthic organisms, echinoderms have exploited temporary adhesion most efficiently. In echinoderms, adhesive systems are usually associated with the podia and are involved in locomotion, attachment, feeding, or burrowing (Flammang, 1996). The paucity of information regarding the adhesive strength of echinoderm podia is due possibly to the fact that these animals possess a multitude of podia that are not all attached at the same time, making it difficult to evaluate the exact number of podia involved in adhesion at any precise instant in time. For example, maximum detachment forces involving many podia have been measured for several asteroid species. Feder (1955) measured up to 4 kg (39·64 N) in Pisaster ochraceus, Lavoie (1956) over 3 kg (29·43 N) in Asterias forbesi, and Christensen (1957) 5 kg (49·05 N) in Evasterias troscheli. Unfortunately, the number of podia adhering to the substratum was not estimated in any of these studies. It is not possible, therefore, to calculate tenacity (adhesive force per unit of surface area) which makes comparisons impossible either between these different asteroids or with other marine invertebrates (see Walker, 1987). Tenacity has been considered in only one study (Paine, 1926) where the mean adhesive force using single podia of the asteroid A. vulgaris was 17·2 g (0·17 N), giving, when divided by a mean measurement of the surface area of the podial discs, a tenacity of 1·25×105 N m2.
The larval development of the parasitic barnacle, Sacculina carcini, has been closely followed. Size and volume measurements have been made for the four naupliar stages and cyprids of both male and female broods. Volume increases between naupliar stages are minimal (x 1.03–1.09) and in line with other barnacle species with lecithotrophic larvae. However, the large volume reduction between stage IV and cyprid for S. carcini, which is more acute for the female larvae, is a unique characteristic. The reduced setation formulae of the larval appendages of S. carcini and another rhizocephalan are compared to those of larvae, both lecithotrophic and planktotrophic, of a range of barnacles. Sex ratios and carapace length data for 184 S. carcini cypris populations are presented which reinforce the seasonal changes in sex ratios.