Inter-observer agreement for diagnostic classification of esophageal motility disorders defined in high-resolution manometry

High-resolution esophageal manometry (HRM) is a recent development used in the evaluation of esophageal function. Our aim was to assess the inter-observer agreement for diagnosis of esophageal motility disorders using this technology. Practitioners registered on the HRM Working Group website were invited to review and classify (i) 147 individual water swallows and (ii) 40 diagnostic studies comprising 10 swallows using a drop-down menu that followed the Chicago Classification system. Data were presented using a standardized format with pressure contours without a summary of HRM metrics. The sequence of swallows was fixed for each user but randomized between users to avoid sequence bias. Participants were blinded to other entries. (i) Individual swallows were assessed by 18 practitioners (13 institutions). Consensus agreement (≤2/18 dissenters) was present for most cases of normal peristalsis and achalasia but not for cases of peristaltic dysmotility. (ii) Diagnostic studies were assessed by 36 practitioners (28 institutions). Overall inter-observer agreement was 'moderate' (kappa 0.51) being 'substantial' (kappa > 0.7) for achalasia type I/II and no lower than 'fair-moderate' (kappa >0.34) for any diagnosis. Overall agreement was somewhat higher among those that had performed >400 studies (n = 9; kappa 0.55) and 'substantial' among experts involved in development of the Chicago Classification system (n = 4; kappa 0.66). This prospective, randomized, and blinded study reports an acceptable level of inter-observer agreement for HRM diagnoses across the full spectrum of esophageal motility disorders for a large group of clinicians working in a range of medical institutions. Suboptimal agreement for diagnosis of peristaltic motility disorders highlights contribution of objective HRM metrics.

Quantification of water content across a cement-clay interface using high resolution neutron radiography

In many designs for radioactive waste repositories, cement and clay will come into direct contact. The geochemical contrast between cement and clay will lead to mass fluxes across the interface, which consequently results in alteration of structural and transport properties of both materials that may affect the performance of the multi-barrier system. We present an experimental approach to study cement-clay interactions with a cell to accommodate small samples of cement and clay. The cell design allows both in situ measurement of water content across the sample using neutron radiography and measurement of transport parameters using through-diffusion tracer experiments. The aim of the high- resolution neutron radiography experiments was to monitor changes in water content (porosity) and their spatial extent. Neutron radiographs of several evolving cement-clay interfaces delivered quantitative data which allow resolving local water contents within the sample domain. In the present work we explored the uncertainties of the derived water contents with regard to various input parameters and with regard to the applied image correction procedures. Temporal variation of measurement conditions created absolute uncertainty of the water content in the order of ±0.1 (m3/m3), which could not be fully accounted for by correction procedures. Smaller relative changes in water content between two images can be derived by specific calibrations to two sample regions with different, invariant water contents.

Understanding measured water rotational temperatures and column densities in the very innermost coma of Comet 73P/Schwassmann–Wachmann 3 B

Direct sublimation of a comet nucleus surface is usually considered to be the main source of gas in the coma of a comet. However, evidence from a number of comets including the recent spectacular images of Comet 103P/Hartley 2 by the EPOXI mission indicates that the nucleus alone may not be responsible for all, or possibly at times even most, of the total amount of gas seen in the coma. Indeed, the sublimation of icy grains, which have been injected into the coma, appears to constitute an important source. We use the fully-kinetic Direct Simulation Monte Carlo model of Tenishev et al. (Tenishev, V.M., Combi, M.R., Davidsson, B. [2008]. Astrophys. J., 685, 659−677; Tenishev, V.M., Combi, M.R., Rubin, M. [2011]. Astrophys. J., 732) to reproduce the measurements of column density and rotational temperature of water in Comet 73P-B/Schwassmann–Wachmann 3 obtained with a very high spatial resolution of ∼30 km using IRCS/Subaru in May 2006 (Bonev, B.P., Mumma, M.J., Kawakita, H., Kobayashi, H., Villanueva, G.L. [2008]. Icarus, 196, 241−248). For gas released solely from the cometary nucleus at a heliocentric distance of 1 AU, modeled rotational temperatures start at 110 K close to the surface and decrease to only several tens of degrees by 10–20 nucleus radii. However, the measured decay of both rotational temperature and column density with distance from the nucleus is much slower than predicted by this simple model. The addition of a substantial (distributed) source of gas from icy grains in the model slows the decay in rotational temperature and provides a more gradual drop in column density profiles. Together with a contribution of rotational heating of water molecules by electrons, the combined effects allow a much better match to the IRCS/Subaru observations. From the spatial distributions of water abundance and temperature measured in 73P/SW3-B, we have identified and quantified multiple mechanisms of release. The application of this tool to other comets may permit such studies over a range of heliocentric and geocentric distances.

Seasonal variation of high-molecular-weight compounds in the water-soluble fraction of organic urban aerosols

Aerosol samples were collected in Zurich, Switzerland, at an urban background site and were analyzed with size exclusion chromatography (SEC) and laser/desorption ionization mass spectrometry (LDI-MS) for water-soluble organic compounds with high molecular weight. Daily samples were collected during two campaigns in winter and summer, for 1 month each. The concentration of high-molecular-weight compounds (humic-like substances (HULIS)) was between 0.4 and 4 μg/m3 in winter and summer. The most intense signals in the LDI-MS mass spectra were measured between m/z150 and 500, comparing well with the mode of the two main high mass peaks determined with SEC corresponding to masses between 200 and 600 Da. For the maximum molecular weight, however, different results were obtained by the two techniques: whereas a maximum molecular weight between 1300 and 3300 Da was found with SEC, hardly any peaks above m/z700 were measured with LDI-MS. During summer the maximum molecular weight of HULIS (determined with SEC) correlates positively with several parameters such as ozone and increased temperature indicative of enhanced atmospheric photo-oxidation. The HULIS concentration also correlates positively with the oxalic acid concentration in the particles. This suggests that HULIS are generated by secondary processes in summer. The lack of such correlations during winter suggests that other sources and processes might be important during colder seasons.

Comparison of homeopathic globules prepared from high and ultra-high dilutions of various starting materials by ultraviolet light spectroscopy

Objective Homeopathic globules are commonly used in clinical practice, while research focuses on liquid potencies. Sequential dilution and succussion in their production process has been proposed to change the physico-chemical properties of the solvent(s). It has been reported that aqueous potencies of various starting materials showed significant differences in ultraviolet light transmission compared to controls and between different dilution levels. The aim of the present study was to repeat and expand these experiments to homeopathic globules. Methods Globules were specially produced for this study by Spagyros AG (Gümligen, Switzerland) from 6 starting materials (Aconitum napellus, Atropa belladonna, phosphorus, sulfur, Apis mellifica, quartz) and for 6 dilution levels (6x, 12x, 30c, 200c, 200CF (centesimal discontinuous fluxion), 10,000CF). Native globules and globules impregnated with solvents were used as controls. Globules were dissolved in ultrapure water, and absorbance in the ultraviolet range was measured. The average absorbance from 200 to 340 nm was calculated and corrected for differences between measurement days and instrumental drift. Results Statistically significant differences were found for A. napellus, sulfur, and A. mellifica when normalized average absorbance of the various dilution levels from the same starting material (including control and solvent control globules) was compared. Additionally, absorbance within dilution levels was compared among the various starting materials. Statistically significant differences were found among 30c, 200c and 200CF dilutions. Conclusion This study has expanded previous findings from aqueous potencies to globules and may indicate that characteristics of aqueous high dilutions may be preserved and detectable in dissolved globules.

The promoting effect of water on the electroreduction of CO2 in acetonitrile

The promoting effect of water on the electrochemical reduction of carbon dioxide (CO2) from non-aqueous solvents has been studied by means of cyclic voltammetry and in-situ surface-enhanced infrared absorption spectroscopy (SEIRAS). CO2 electroreduction on gold is known to be highly selective towards CO formation in aqueous and in non-aqueous media. The use of non-aqueous solvents is advantageous due to the significantly increased solubility of CO2 compared to aqueous systems. However, in the absence of any proton source, extremely high overpotentials are required for the CO2 electroreduction. In this work, we demonstrate for the first time a tremendous accelerating effect of water additives on the electroreduction of CO2 taking place at gold/acetonitrile interfaces. Already moderate amounts of water, in the concentration range of 0.5 to 0.7 M, are sufficient to decrease significantly the overpotential of CO2 reduction while keeping the CO2 concentration as high as in the pure acetonitrile. The effect of water additives on the mechanism of CO2 electroreduction on gold is discussed on the basis of electrochemical and IR spectroscopic data. The results obtained from gold are compared to analogue experiments carried out on platinum.

Influence of catchment quality and altitude on the water and sediment composition of 68 small lakes in Central Europe

68 lakes (63 Swiss, 2 French and 3 Italian) located in an altitudinal range between 334 and 2339m spanning a wide range of land-use have been investigated. The aim of the study was to discuss influences of geographic location, vegetation and land-use in the catchment area on the water and sediment chemistry of small lakes. Detailed quantitative description of land-use, vegetation, and climate in the watershed of all lakes was established. Surface and bottom water samples collected from each lake were analyzed for major ions and nutrients. Correlations were interpreted using linear regression analysis. Chemical parameters of water and sediment reflect the characteristics of the catchment areas. All lakes were alkaline since they were situated on calcareous bedrock. Concentrations of nitrogen and phosphorus strongly increase with increasing agricultural land-use. Na and K, however, are positively correlated with the amount of urbanization within the catchment area. These elements as well as dissolved organic carbon (DOC), Mg, Ca, and alkalinity, increase when the catchment is urbanized or used for agriculture. Total nitrogen and organic carbon in the sediments decrease distinctly if large parts of the catchment consist of bare land. No correlations between sediment composition and maximum water depth or altitude of the lakes were found.¶Striking differences in the water compositions of lakes above and below approximately 700 m of altitude were observed. Concentrations of total nitrogen and nitrate, total phosphorus, DOC, Na, K, Mg, Ca, and alkalinity are distinctly higher in most lakes below 700 m than above, and the pH of the bottom waters of these lakes is generally lower. Estimates of total nitrogen concentrations, even in remote areas, indicate that precipitation is responsible for increased background concentrations. At lower altitudes nitrogen concentrations in lakes is explained by the nitrogen loaded rain from urban areas deposited on the catchment, and with high percentages of agricultural land-use in the watershed.

Comprehensive environmental study in high risk areas for cancer patients comparing air and water Aspergillus species samples

Background. Nosocomial invasive aspergillosis (a highly fatal disease) is an increasing problem for immunocompromised patients. Aspergillus spp. can be transmitted via air (most commonly) and by water. ^ The hypothesis for this prospective study was that there is an association between patient occupancy, housekeeping practices, patients, visitors, and Aspergillus spp. loading. Rooms were sampled as not terminally cleaned (dirty) and terminally cleaned (clean). The secondary hypothesis was that Aspergillus spp. positive samples collected from more than one sampling location within the same patient room represent the same isolate. ^ Methods. Between April and October 2004, 2873 environmental samples (713 air, 607 water, 1256 surface and 297 spore traps) were collected in and around 209 “clean” and “dirty” patient rooms in a large cancer center hospital. Water sources included aerosolized water from patient room showerheads, sinks, drains, and toilets. Bioaerosol samples were from the patient room and from the running shower, flushing toilet, and outside the building. The surface samples included sink and shower drains, showerheads, and air grills. Aspergillus spp. positive samples were also sent for PCR, molecular typing (n = 89). ^ Results. All water samples were negative for Aspergillus spp. There were a total of 130 positive culturable samples (5.1%). The predominant species found was Aspergillus niger. Of the positive culturable samples, 106 (14.9%) were air and 24 (3.8%) were surface. There were 147 spore trap samples, and 49.5% were positive for Aspergillus/Penicillum spp. Of the culturable positive samples sent for PCR, 16 were indistinguishable matches. There was no significant relationship between air and water samples and positive samples from the same room. ^ Conclusion. Primarily patients, visitors and staff bring the Aspergillus spp. into the hospital. The high number of A. niger samples suggests the spores are entering the hospital from outdoors. Eliminating the materials brought to the patient floors from the outside, requiring employees, staff, and visitors to wear cover up over their street clothes, and improved cleaning procedures could further reduce positive samples. Mold strains change frequently; it is probably more significant to understand pathogenicity of viable spores than to commit resources on molecular strain testing on environmental samples alone. ^

Daily polynya area and ice production in the North Water polynya region

The North Water (NOW) Polynya is a regularly-forming area of open-water and thin-ice, located between northwestern Greenland and Ellesmere Island (Canada) at the northern tip of Baffin Bay. Due to its large spatial extent, it is of high importance for a variety of physical and biological processes, especially in wintertime. Here, we present a long-term remote sensing study for the winter seasons 1978/1979 to 2014/2015. Polynya characteristics are inferred from (1) sea ice concentrations and brightness temperatures from passive microwave satellite sensors (Advanced Microwave Scanning Radiometer (AMSR-E and AMSR2), Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave Imager/Sounder (SSM/I-SSMIS)) and (2) thin-ice thickness distributions, which are calculated using MODIS ice-surface temperatures and European Center for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis data in a 1D thermodynamic energy-balance model. Daily ice production rates are retrieved for each winter season from 2002/2003 to 2014/2015, assuming that all heat loss at the ice surface is balanced by ice growth. Two different cloud-cover correction schemes are applied on daily polynya area and ice production values to account for cloud gaps in the MODIS composites. Our results indicate that the NOW polynya experienced significant seasonal changes over the last three decades considering the overall frequency of polynya occurrences, as well as their spatial extent. In the 1980s, there were prolonged periods of a more or less closed ice cover in northern Baffin Bay in winter. This changed towards an average opening on more than 85% of the days between November and March during the last decade. Noticeably, the sea ice cover in the NOW polynya region shows signs of a later-appearing fall freeze-up, starting in the late 1990s. Different methods to obtain daily polynya area using passive microwave AMSR-E/AMSR2 data and SSM/I-SSMIS data were applied. A comparison with MODIS data (thin-ice thickness < 20 cm) shows that the wintertime polynya area estimates derived by MODIS are about 30 to 40% higher than those derived using the polynya signature simulation method (PSSM) with AMSR-E data. In turn, the difference in polynya area between PSSM and a sea ice concentration (SIC) threshold of 70% is fairly low (approximately 10%) when applied to AMSR-E data. For the coarse-resolution SSM/I-SSMIS data, this difference is much larger, particularly in November and December. Instead of a sea ice concentration threshold, the PSSM method should be used for SSM/I-SSMIS data. Depending on the type of cloud-cover correction, the calculated ice production based on MODIS data reaches an average value of 264.4 ± 65.1 km**3 to 275.7 ± 67.4 km**3 (2002/2003 to 2014/2015) and shows a high interannual variability. Our achieved long-term results underline the major importance of the NOW polynya considering its influence on Arctic ice production and associated atmosphere/ocean processes.

Chlorophyll a and carbon fluxes, and characteristics of the water column during summer 2008 in the Beaufort Sea

Following the extreme low ice year of 2007, primary production and the sinking export of particulate and gel-like organic material, using short-term particle interceptor traps deployed at 100 m, were measured in the southeastern Beaufort Sea during summer 2008. The combined influence of early ice retreat and coastal upwelling contributed to exceptionally high primary production (500 ± 312 mg C/m**2/day, n = 7), dominated by large cells (>5 µm, 73% ± 15%, n = 7). However, except for one station located north of Cape Bathurst, the sinking export of particulate organic carbon (POC) was relatively low (range: 38-104 mg C/m**2/day, n = 12) compared to other productive Arctic shelves. Estimates indicate that 80% ± 20% of the primary production was cycled through large copepods or the microbial food web. Exopolymeric substances were abundant in the sinking material but did not appear to accelerate POC sinking export. The use of isotopic signatures (d13C, d15N) and carbon/nitrogen ratios to identify sources of the sinking material was successful only at two stations with a strong marine or terrestrial signature, indicating the limitations of this approach in hydrographically and biologically complex Arctic coastal waters such as in the Beaufort Sea. At these two stations influenced by either coastal upwelling or erosion, the composition and magnitude of particulate sinking fluxes were markedly different from other stations visited during the study. These observations underscore the fundamental role of mesoscale circulation patterns and hydrodynamic singularities on the export of particulate organic material on Arctic shelves.

Physicochemical and photosynthetic characteristics of water samples obtained during a CCGS Amundsen cruise in 2008

During summer 2008, as part of the Circumpolar Flaw Lead system study, we measured phytoplankton photosynthetic parameters to understand regional patterns in primary productivity, including the degree and timescale of photoacclimation and how variability in environmental conditions influences this response. Photosynthesis-irradiance measurements were taken at 15 sites primarily from the depth of the subsurface chlorophyll a (Chl a) maximum (SCM) within the Beaufort Sea flaw lead polynya. The physiological response of phytoplankton to a range of light levels was used to assess maximum rates of carbon (C) fixation (P*m), photosynthetic efficiency (alpha*), photoacclimation (Ek), and photoinhibition (beta*). SCM samples taken along a transect from under ice into open water exhibited a >3-fold increase in alpha* and P*m, showing these parameters can vary substantially over relatively small spatial scales, primarily in response to changes in the ambient light field. Algae were able to maintain relatively high rates of C fixation despite low light at the SCM, particularly in the large (>5 µm) size fraction at open water sites. This may substantially impact biogenic C drawdown if species composition shifts in response to future climate change. Our results suggest that phytoplankton in this region are well acclimated to existing environmental conditions, including sea ice cover, low light, and nutrient pulses. Furthermore, this photoacclimatory response can be rapid and keep pace with a developing SCM, as phytoplankton maintain photosynthetic rates and efficiencies in a narrow ''shade-acclimated'' range.

The hydrographic conditions at depth below 1000 m water depth in the region of the Romanche Fracture Zones

During the "Atlantic Expedition" in1965 (IQSY) a comprehensive bathymetric survey and a few hydrographic stations were made by R.V. "Meteor" in the equatorial region of the Mid-Atlantic Ridge. The survey results are shown in a bythymetric chart covering the western parts of the Romanche- and Chain Fracture Zones. West of the original Romanche Trench another deep trench with a medium depth of 6000 m was discovered. The maximum sounding obtained was 7028 m. Both trenches apparently belong to the same fracture zone, but are distinctly separated from each other. The estern boundary of the trench against the Brasil Basin is formed by a sill rising to a depth of about 4400 m. The serial hydrographic observations give some indications of the flow of the cold Westatlantic deep water in the fracture zone area and its influence on the hydrographic conditions in the East-Atlantic Basin. The upper limit of the nearly homogenious Westatlantic bottom water with an Antarctic components lies about 4400 m. The water mass entering the system of trenches of the Romanche Fracture Zone over the western sill originates from the lower part of the discontinuity layer lying above the bottom water. Potential temperatures of 0.6°C were the lowest observed by "Meteor" in the western trench. There seems to be a remarkable tongue of relatively high salinity and a minimum of oxygen in the deep water of this trench. At present we can only speculate upon the origin of this highly saline deep water tongue underneath the eastward moving relatively thin layer of less saline Westatlantic deep water. In the range of the sill separating both trenches a lee wave is indicated by the distribution of salinity and oxygen, which implies a vertical transport of water masses. Caused by this transport it is assumed that relatively cold water may be lifted temporarily to a depth, where it can pass the northbounding ridge, thus getting directly into the Sierra Leone Basin. In the original Romanche Trench the cold Westatlantic deep water seems to fill the whole trough, but its extension remains limited to the trench itself. The water masses found east of the sill separating the trench from the East-Atlantic Basin originate from the lower part of the discontinuity layer. With potential temperatures of about 1.3°C they are much warmer than those observed in the Romanche Trench bottom water.

Multi-year high-frequency current and water quality in-situ observations at the Guadiana Estuary

High-frequency data collected continuously over a multiyear time frame are required for investigating the various agents that drive ecological and hydrodynamic processes in estuaries. Here, we present water quality and current in-situ observations from a fixed monitoring station operating from 2008 to 2014 in the lower Guadiana Estuary, southern Portugal (37°11.30' N, 7°24.67' W). The data were recorded by a multi-parametric probe providing hourly records (temperature, salinity, chlorophyll, dissolved oxygen, turbidity, and pH) at a water depth of ~1 m, and by a bottom-mounted acoustic Doppler current profiler measuring the pressure, near-bottom temperature, and flow velocity through the water column every 15 min. The time-series data, in particular the probe ones, present substantial gaps arising from equipment failure and maintenance, which are ineluctable with this type of observations in harsh environments. However, prolonged (months-long) periods of multi-parametric observations during contrasted external forcing conditions are available. The raw data are reported together with flags indicating the quality status of each record. River discharge data from two hydrographic stations located near the estuary head are also provided to support data analysis and interpretation.