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Laboratory Measurements (laboratory + measurement)
Selected AbstractsLaboratory measurement of schistocytesINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 2 2007J.-F. Lesesve No abstract is available for this article. [source] Vesta, Vestoids, and the howardite, eucrite, diogenite group: Relationships and the origin of spectral differencesMETEORITICS & PLANETARY SCIENCE, Issue 6 2001T. H. Burbine All of the measured small asteroids (except for 2579 Spartacus) have reflectance spectra consistent with surface compositions similar to eucrites and howardites and consistent with all being derived from Vesta. None of the observed asteroids have spectra similar to diogenites. We find no spectral distinction between the 15 objects tabulated as members of the Vesta dynamical family and 6 of the 7 sampled "non-family" members that reside just outside the semi-major axis (a), eccentricity (e), and inclination (i) region of the family. The spectral consistency and close orbital (a-e-i) match of these "non-family" objects to Vesta and the Vesta family imply that the true bounds of the family extend beyond the subjective cut-off for membership. Asteroid 2579 Spartacus has a spectrum consistent with a mixture of eucritic material and olivine. Spartacus could contain olivine-rich material from Vesta's mantle or may be unrelated to Vesta altogether. Laboratory measurements of the spectra of eucrites show that samples having nearly identical compositions can display a wide range of spectral slopes. Finer particle sizes lead to an increase in the slope, which is usually referred to as reddening. This range of spectral variation for the best-known meteoritic analogs to the Vestoids, regardless of whether they are actually related to each other, suggests that the extremely red spectral slopes for some Vestoids can be explained by very fine-grained eucritic material on their surfaces. [source] Parthenogenetic flatworms have more symbionts than their coexisting, sexual conspecifics, but does this support the Red Queen?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2001N. K. Michiels The Red Queen hypothesis predicts that sexuality is favoured when virulent parasites adapt quickly to host genotypes. We studied a population of the flatworm Schmidtea polychroa in which obligate sexual and parthenogenetic individuals coexist. Infection rates by an amoeboid protozoan were consistently higher in parthenogens than in sexuals. Allozyme analysis showed that infection was genotype specific, with the second most common clone most infected. A laboratory measurement of fitness components failed to reveal high infection costs as required for the Red Queen. Although fertility was lower in more infected parthenogens, this effect can also be explained by the accumulation of mutations. We discuss these and other characteristics of our model system that may explain how a parasite with low virulence can show this pattern. [source] Large-scale distribution and activity patterns of an extremely low-light-adapted population of green sulfur bacteria in the Black SeaENVIRONMENTAL MICROBIOLOGY, Issue 5 2010Evelyn Marschall Summary The Black Sea chemocline represents the largest extant habitat of anoxygenic phototrophic bacteria and harbours a monospecific population of Chlorobium phylotype BS-1. High-sensitivity measurements of underwater irradiance and sulfide revealed that the optical properties of the overlying water column were similar across the Black Sea basin, whereas the vertical profiles of sulfide varied strongly between sampling sites and caused a dome-shaped three-dimensional distribution of the green sulfur bacteria. In the centres of the western and eastern basins the population of BS-1 reached upward to depths of 80 and 95 m, respectively, but were detected only at 145 m depth close to the shelf. Using highly concentrated chemocline samples from the centres of the western and eastern basins, the cells were found to be capable of anoxygenic photosynthesis under in situ light conditions and exhibited a photosynthesis,irradiance curve similar to low-light-adapted laboratory cultures of Chlorobium BS-1. Application of a highly specific RT-qPCR method which targets the internal transcribed spacer (ITS) region of the rrn operon of BS-1 demonstrated that only cells at the central station are physiologically active in contrast to those at the Black Sea periphery. Based on the detection of ITS-DNA sequences in the flocculent surface layer of deep-sea sediments across the Black Sea, the population of BS-1 has occupied the major part of the basin for the last decade. The continued presence of intact but non-growing BS-1 cells at the periphery of the Black Sea indicates that the cells can survive long-distant transport and exhibit unusually low maintenance energy requirements. According to laboratory measurements, Chlorobium BS-1 has a maintenance energy requirement of ,1.6,4.9·10,15 kJ cell,1 day,1 which is the lowest value determined for any bacterial culture so far. Chlorobium BS-1 thus is particularly well adapted to survival under the extreme low-light conditions of the Black Sea, and can be used as a laboratory model to elucidate general cellular mechanisms of long-term starvation survival. Because of its adaptation to extreme low-light marine environments, Chlorobium BS-1 also represents a suitable indicator for palaeoceanography studies of deep photic zone anoxia in ancient oceans. [source] Sampling and analytical plus subsampling variance components for five soil indicators observed at regional scaleEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 5 2009B. G. Rawlins Summary When comparing soil baseline measurements with resampled values there are four main sources of error. These are: i) location (errors in relocating the sample site), ii) sampling errors (representing the site with a sample of material) iii) subsampling error (selecting material for analysis) and iv) analytical error (error in laboratory measurements). In general we cannot separate the subsampling and analytical sources of error (since we always analyse a different subsample of a specimen), so in this paper we combine these two sources into subsampling plus analytical error. More information is required on the relative magnitudes of location and sampling errors for the design of effective resampling strategies to monitor changes in soil indicators. Recently completed soil surveys of the UK with widely differing soils included a duplicate site and subsampling protocol to quantify ii), and the sum of iii) and iv) above. Sampling variances are estimated from measurements on duplicate samples , two samples collected on a support of side length 20 m separated by a short distance (21 m). Analytical and subsampling variances are estimated from analyses of two subsamples from each duplicate site. After accounting for variation caused by region, parent material class and land use, we undertook a nested analysis of data from 196 duplicate sites across three regions to estimate the relative magnitude of medium-scale (between sites), sampling and subsampling plus analytical variance components, for five topsoil indicators: total metal concentrations of copper (Cu), nickel (Ni) and zinc (Zn), soil pH and soil organic carbon (SOC) content. The variance components for each indicator diminish by about an order of magnitude from medium-scale, to sampling, to analytical plus subsampling. Each of the three fixed effects (parent material, land use and region) were statistically significant for each of the five indicators. The most effective way to minimise the overall uncertainty of our observations at sample sites is to reduce the sampling variance. [source] Effects of soil improvement treatments on bacterial community structure and soil processes in an upland grassland soilFEMS MICROBIOLOGY ECOLOGY, Issue 1 2003Neil D. Gray Abstract Temporal temperature gradient electrophoresis (TTGE) analysis of 16S rRNA gene fragments amplified with primers selective for eubacteria and ,-proteobacterial ammonia-oxidising bacteria (AOB) was used to analyse changes in bacterial and AOB community profiles of an upland pasture following soil improvement treatments (addition of sewage sludge and/or lime). Community structure was compared with changes in activity assessed by laboratory measurements of basal respiration and ammonia oxidation potentials, and with measurements of treatment- and time-related changes in soil characteristics. The predominant bacterial populations had a high degree of similarity under all treatment regimens, which was most pronounced early in the growing season. Most of the differences that occurred between soil samples with time could be accounted for by spatial and temporal variation; however, analysis of variance and cluster analysis of similarities between 16S rDNA TTGE profiles indicated that soil improvement treatments exerted some effect on community structure. Lime application had the greatest influence. The impact of soil improvement treatments on autotrophic ammonia oxidation was significant and sustained, especially in soils which had received sewage sludge and lime treatments in combination. However, despite obvious changes in soil characteristics, e.g. pH and soil nitrogen, increasing heterogeneity in the AOB community structure over time obscured the treatment effects observed at the beginning of the experiment. Nevertheless, time series analysis of AOB TTGE profiles indicated that the AOB community in improved soils was more dynamic than in control soils where populations were found to be relatively stable. These observations suggest that the AOB populations exhibited a degree of functional redundancy. [source] Hydrologic responses to earthquakes and a general metricGEOFLUIDS (ELECTRONIC), Issue 1-2 2010CHI-YUEN WANG Geofluids (2010) 10, 206,216 Abstract Hydrologic responses to earthquakes, including liquefaction, changes in stream and spring discharge, changes in the properties of groundwater such as geochemistry, temperature and turbidity, changes in the water level in wells, and the eruption of mud volcanoes, have been documented for thousands of years. Except for some water-level changes in the near field which can be explained by poroelastic responses to static stress changes, most hydrologic responses, both within and beyond the near field, can only be explained by the dynamic responses associated with seismic waves. For these responses, the seismic energy density e may be used as a general metric to relate and compare the various hydrologic responses. We show that liquefaction, eruption of mud volcanoes and increases in streamflow are bounded by e , 10,1 J m,3; temperature changes in hot springs are bounded by e , 10,2 J m,3; most sustained groundwater changes are bounded by e , 10,3 J m,3; geysers and triggered seismicity may respond to seismic energy density as small as 10,3 and 10,4 J m,3, respectively. Comparing the threshold energy densities with published laboratory measurements, we show that undrained consolidation induced by dynamic stresses can explain liquefaction only in the near field, but not beyond the near field. We propose that in the intermediate field and far field, most responses are triggered by changes in permeability that in turn are a response to the cyclic deformation and oscillatory fluid flow. Published laboratory measurements confirm that changes in flow and time-varying stresses can change permeability, inducing both increases and decreases. Field measurements in wells also indicate that permeability can be changed by earthquakes in the intermediate field and far field. Further work, in particular field monitoring and measurements, are needed to assess the generality of permeability changes in explaining far-field hydrologic responses to earthquakes. [source] Viscoelastic,afterslip concurrence: a possible mechanism in the early post-seismic deformation of the Mw 7.6, 1999 Chi-Chi (Taiwan) earthquakeGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2004Shyh-Yang Sheu SUMMARY Observed coseismic data as well as 97 days of post-seismic GPS data for the Chi-Chi earthquake are used as constraints in the modelling of crustal evolution using the 3-D finite-element method. First, the coseismic GPS data are used to justify the use of the elastic earth model and the source rupture model. Subsequently, the most likely rheological model is determined by analysing several modelled time-dependent displacements for various viscosity structures. The range of viscosities of the lower crust in central Taiwan is determined in advance from laboratory measurements and the long-term strain rate. The estimated viscosity of 5.0 × 1017 Pa s seems to be very low and a relaxation time of 116 days seems very short, but the latter approximates the GPS measurement of 86 days. Since earlier studies have indicated that both the viscoelastic response model and the afterslip model may affect post-seismic deformation, we compare theoretical surface displacements for each of the two models that we evaluate. The results reveal that there is little doubt that while neither of these models alone is able to predict the GPS measurements well in a 97-day period, the combination of the two models improves the predictions considerably. We conclude that the afterslip mainly dominated Chi-Chi post-seismic deformation in the rupture area while the viscoelastic model did so elsewhere. [source] The stress sensitivity of shaley sandstonesGEOPHYSICAL PROSPECTING, Issue 2 2007Colin MacBeth ABSTRACT The link between the stress sensitivity of shaley sandstones and their porosity and clay content is investigated. This is achieved by firstly fitting a compliance-based stress-sensitivity law to laboratory measurements of ultrasonic velocity taken from four sets of reservoir sandstones, extracted from a variety of depositional settings. Correlations are then sought between the independent parameters of this law and the porosity or clay fraction of the rocks, which are then subsequently interpreted in terms of framework or pore-space-related microstructural clay models. The general conclusion drawn from the results is that both of the parameters defining the stress-sensitivity law (the asymptotic modulus and the stress-dependent excess compliance) clearly vary with porosity. However, only the asymptotic modulus shows a convincing trend with clay and there is little observed variation of the stress-dependent compliance with clay. There is therefore a resultant variation of stress sensitivity with clay, but it is controlled only by the asymptotic modulus. The analysis also concludes that all four data sets fall into a framework-related category of clay model. [source] Reliability and construct validity of the compatible MRI scoring system for evaluation of elbows in haemophilic childrenHAEMOPHILIA, Issue 2 2008A. S. DORIA Summary., We assessed the reliability and construct validity of the Compatible MRI scale for evaluation of elbows, and compared the diagnostic performance of MRI and radiographs for assessment of these joints. Twenty-nine MR examinations of elbows from 27 boys with haemophilia A and B [age range, 5,17 years (mean, 11.5)] were independently read by four blinded radiologists on two occasions. Three centres participated in the study: (Toronto, n = 24 examinations; Atlanta, n = 3; Cuiaba, n = 2). The number of previous joint bleeds and severity of haemophilia were reference standard measures. The inter-reader reliability of MRI scores was substantial (ICC = 0.73) for the additive (A)-scale and excellent (ICC = 0.83) for the progressive (P)-scale. The intrareader reliability was excellent for both P-scores (ICC = 0.91) and A-scores (ICC = 0.93). The total P- and A-scores correlated poorly (r = 0.36) or moderately (r = 0.54), but positively, with clinical-laboratory measurements. The total MRI scores demonstrated high accuracy for discrimination of presence or absence of arthropathy [P-scale, area-under-the-curve (AUC) = 0.94 ± 0.05; A-scale, AUC = 0.89 ± 0.06], as did the soft tissue scores of both scales (P-scale, AUC = 0.90 ± 0.06; A-scale, AUC = 0.86 ± 0.06). Areas-under-the-curve used to discriminate severe disease demonstrated high accuracy for both P-MRI scores (AUC = 0.83 ± 0.09) and A-MRI scores (AUC = 0.87 ± 0.09), but non-diagnostic ability to discriminate mild disease. Similar results were noted for radiographic scales. In conclusion, both MRI scales demonstrated substantial to excellent reliability and accuracy for discrimination of presence/absence of arthropathy, and severe/non-severe disease, but poor to moderate convergent validity for total scores and non-diagnostic discriminant validity for mild/non-mild disease. Compared with radiographic scores, MRI scales did not perform better for discrimination of severity of arthropathy. [source] Biomarkers in Migraine: Their Promise, Problems, and Practical ApplicationsHEADACHE, Issue 7 2006Elizabeth Loder MD Biomarkers are physical signs or laboratory measurements that "occur in association with a pathological process and have putative diagnostic and/or prognostic utility." Biomarkers hold considerable promise for understanding and intervening in the disease process of migraine. They may permit recognition of individuals at risk of developing migraine, improve the timing, accuracy, and precision of migraine diagnosis, and serve as indicators of treatment response and disease progression. Furthermore, they hold great promise for research. At the same time, there are important limitations to the use of biomarkers in migraine, including problems with validity, reliability, accuracy, and precision. Legal, ethical, and cost considerations are also important. This review describes the potential uses and limitations of biomarkers in migraine diagnosis, treatment, and research. [source] Validation of a simple model for predicting liver fibrosis in HIV/hepatitis C virus-coinfected patientsHIV MEDICINE, Issue 6 2005H Al-Mohri Objectives Recently, several models incorporating laboratory measurements have been validated for use as surrogate markers for liver fibrosis in hepatitis C virus (HCV) mono-infection, the simplest of these being the aspartate aminotransferase (AST) to platelet ratio index (APRI). We evaluated how well the APRI predicts significant hepatic fibrosis in patients with HIV/HCV coinfection. Methods Forty-six HIV/HCV-coinfected patients who underwent liver biopsy and had concomitant laboratory measurements (±3 months) were included in the study. Significant fibrosis was defined as F2,F4 using Batt and Ludwig scoring (=3 Ishak). APRI=[(AST/upper limit of normal)/platelet count (109/L)] × 100. We used sas proc logistic (SAS Institute, Cary, NC) to calculate the area under the receiver operating curve (ROC) (AUC). Sensitivities, specificities, positive predictive value (PPV) and negative predictive value (NPV) were compared using cut-offs previously identified in the literature. Results Thirty-three of 46 patients (72%) had significant fibrosis on biopsy. For significant fibrosis, the area under the ROC for the APRI was 0.847±0.057. APRI scores >1.5 (the higher cut-off) were 100% specific and 52% sensitive; PPV was 100% and NPV 45%. Scores <0.5 (the lower cut-off) were 82% sensitive and 46% specific in ruling out significant fibrosis (PPV 79%; NPV 50%). Conclusions A simple model incorporating readily available laboratory data is highly predictive of significant fibrosis in HIV/HCV coinfection and could serve as a biopsy-sparing measure, thus making treatment more accessible for this population. [source] Evaluation of Bioaccumulation Using In Vivo Laboratory and Field Studies,INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2009Annie V Weisbrod Abstract A primary consideration in the evaluation of chemicals is the potential for substances to be absorbed and retained in an organism's tissues (i.e., bioaccumulated) at concentrations sufficient to pose health concerns. Substances that exhibit properties that enable biomagnification in the food chain (i.e., amplification of tissue concentrations at successive trophic levels) are of particular concern due to the elevated long-term exposures these substances pose to higher trophic organisms, including humans. Historically, biomarkers of in vivo chemical exposure (e.g., eggshell thinning, bill deformities) retrospectively led to the identification of such compounds, which were later categorized as persistent organic pollutants. Today, multiple bioaccumulation metrics are available to quantitatively assess the bioaccumulation potential of new and existing chemicals and identify substances that, upon or before environmental release, may be characterized as persistent organic pollutants. This paper reviews the various in vivo measurement approaches that can be used to assess the bioaccumulation of chemicals in aquatic or terrestrial species using laboratory-exposed, field-deployed, or collected organisms. Important issues associated with laboratory measurements of bioaccumulation include appropriate test species selection, test chemical dosing methods, exposure duration, and chemical and statistical analyses. Measuring bioaccumulation at a particular field site requires consideration of which test species to use and whether to examine natural populations or to use field-deployed populations. Both laboratory and field methods also require reliable determination of chemical concentrations in exposure media of interest (i.e., water, sediment, food or prey, etc.), accumulated body residues, or both. The advantages and disadvantages of various laboratory and field bioaccumulation metrics for assessing biomagnification potential in aquatic or terrestrial food chains are discussed. Guidance is provided on how to consider the uncertainty in these metrics and develop a weight-of-evidence evaluation that supports technically sound and consistent persistent organic pollutant and persistent, bioaccumulative, and toxic chemical identification. Based on the bioaccumulation information shared in 8 draft risk profiles submitted for review under the United Nations Stockholm Convention, recommendations are given for the information that is most critical to aid transparency and consistency in decision making. [source] Demand side management for water heating installations in South African commercial buildingsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2001P. G. Rousseau Abstract The largest percentage of the sanitary hot water used in South African buildings is heated by means of direct electrical resistance heaters. This is one of the major contributing factors of the undesirable high morning and afternoon peaks imposed on the national electricity supply grid. Water heating therefore continues to be of concern to ESKOM, the country's only electrical utility company. The so-called in-line water heating system design methodology was developed to address this problem. This paper investigates the potential impact of in-line systems on the national peak electrical demand. A computer simulation model was developed that combines a deterministic mathematical model with a statistical approach in order to predict the diversity factors associated with both the existing and in-line design methodologies. A study was also conducted to estimate the total installed water heating capacity in the national commercial building sector. This figure can be combined with the simulated diversity factor to determine the peak electrical demand. The deterministic model includes the detailed simulation of the hot water storage vessel, the electrical heater and the system control algorithm. The mathematical model for the storage vessel is based on an electrical analogue approach that includes the effects of conduction as well as forced and natural convection. This model was verified extensively with the aid of laboratory measurements and compared with existing storage vessel models. It was found that the new storage vessel model could predict the supply temperature within 2 per cent for a system configuration with the heater in parallel outside the reservoir and within 12 per cent for a configuration with the heater situated inside the reservoir. This compares favourably with existing models found in the literature. The complete simulation based on the statistical approach showed that extensive application of the new design methodology could result in a reduction of approximately 75 MW in the total maximum peak demand imposed on the electricity supply grid in wintertime. This is 58 per cent of the current peak demand due to commercial water heating and 12.5 per cent of the peak load reduction target set by ESKOM until the year 2015. Copyright © 2001 John Wiley & Sons, Ltd. [source] Palpable splenomegaly in children with haemoglobin SC disease: Haematological and clinical manifestationsINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2000S.A. Zimmerman Summary This study aimed to investigate the prevalence of palpable splenomegaly in children with haemoglobin SC (Hb SC) disease, and to determine the haematological and clinical manifestations of splenomegaly in this patient population. We performed a retrospective chart review of 100 patients with Hb SC over 2 years of age followed by the Duke University Paediatric Sickle Cell Program with serial physical examinations and laboratory measurements. Palpable splenomegaly was present in 34% of patients and was more common in males (P = 0.029). Children with splenomegaly had a significantly lower average haemoglobin concentration (10.3 vs. 10.8 g/dl, P = 0.011) and lower platelet count (237 vs. 314 × 109/l, P < 0.001) than those without splenomegaly. Children with measurements both before and after the onset of splenomegaly had a significant decrease in the platelet count (279 vs. 216 × 109/l, P < 0.001) and white blood cell count (9.1 vs. 7.9 × 109/l, P = 0.04) after splenomegaly was identified. Clinical complications included acute splenic sequestration in 12% of children (median age 5.4 years), and hypersplenism with chronic thrombocytopenia in another 10% of patients (median age 10.6 years). Splenomegaly is a common physical finding in children with Hb SC disease and is often associated with mild cytopenias. Clinical complications of splenomegaly include acute splenic sequestration in younger patients and hypersplenism with chronic thrombocytopenia in older children. [source] Photoabsorption processes in nitrous oxide and formaldehydeINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4-5 2001I. Martín Abstract Absorption oscillator strengths and photoionization cross sections for electronic transitions involving Rydberg states that are relevant to the photochemistry of N2O and H2CO are reported. These compounds have been found to play an important role in the evolution of Earth's upper atmosphere. However, the difficulties encoutered in both laboratory measurements and theoretical calculations on the photoabsorption of these compounds are responsible for the scarcity of data in the literature. The present calculations have been performed with the molecular-adapted quantum defect orbital (MQDO) method, of which the adequacy for this type of studies has recently been assessed. A comparative analysis of the photoabsorption intensities in the molecules and their constituting atoms has enabled us to predict the variation of the extent of atomic character of the molecular Rydberg orbitals with the degree of excitation. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001 [source] A phase-space method for arbitrary bimolecular gas-phase reactions: Theoretical descriptionINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 5 2001A. Gross Abstract A theoretical model for the calculation of rate constants for arbitrary bimolecular gas-phase reactions was developed. The method is based on the phase-space statistical method developed by Light and co-workers 1,6. In the present article this method is extended to arbitrary molecular systems. The new method requires knowledge of the molecular properties in the reaction and products channels of the chemical system. The properties are the vibrational frequencies, moments of inertia, and potential energy for the interacting species in their ground state equilibrium configuration. Furthermore, we have to calculate either the energy barrier or the long-range potential for the chemical system (if the reaction channel does not have an energy barrier). The usefulness of the method is that it can be applied to all bimolecular reactions, trimolecular reactions, and even reactions of higher orders. Therefore, it can be applied to cases where rate constants of complex chemical reactions are required, but reliable laboratory measurements or other means to estimate rate parameters are not yet possible. Even if spectroscopic data are not available for the reactants and products, it is possible to use electronic structure theory to calculate the required data. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001 [source] Evaluation of bone surface registration applying a micro-needle arrayJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2007Kurt Schicho Abstract Aim: In this study we present and evaluated a new registration technology for the jaw-bone surface. It is based on a micromechatronic device for the generation of a "mechanical image" of the bone surface by means of an array of micro-needles that are penetrating the soft tissue until they touch the surface of the bone. This "mechanical impression image" is aligned with the CT data set. Material and Methods: Based on laboratory measurements on 10 specially prepared jawbone models we evaluate the accuracy of this new registration method. Results: Our measurements of the 10 specimens revealed a maximum overall location error of 0.97 mm (range: 0.35,0.97 mm). Conclusions: From the technical point of view the presented registration technology has the potential to improve the performance (i.e. accuracy and avoidance of errors) of the registration process for bony structures in selected applications of image-guided surgery. [source] Diurnal variation of sodium and potassium at MercuryMETEORITICS & PLANETARY SCIENCE, Issue 9 2002D. M. HUNTEN The proposed mechanism is deposition of ions and atoms on the cold night side, followed by their outward diffusion and evaporation as the Sun rises. Published criticisms of this mechanism are discussed and answered. The rate at which Na atoms can evaporate from the surfaces of the Moon and Mercury is uncertain, but, after a review of laboratory measurements, we propose that it is substantial at temperatures of 400 K and higher. Possible reasons are discussed why another group does not find the diurnal variation. There are differences in observing geometry, but the matter remains unclear. [source] Mie simulations as an error source in mineral aerosol radiative forcing calculationsTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 623 2007M. Kahnert Abstract The role of aerosols remains a major uncertainty for climate and climate change. For the direct radiative forcing by mineral aerosols, the uncertainty in the refractive index m has been regarded as the most important error source, while the impact of aerosol non-sphericity has been considered a minor issue and is neglected in climate models. Here, the errors caused by the spherical particle approximation (SPA) are evaluated by comparing radiative fluxes based on (i) Mie simulations and (ii) laboratory measurements of aerosol optical properties. Furthermore, they are contrasted with the errors related to the uncertainty in the refractive index. These two error sources are found to be of comparable magnitude, although they are strongly dependent on optical depth, surface albedo, and particle size. Thus, our results provide evidence that, contrary to common beliefs, the use of spherical model particles in radiative transfer simulations is probably among the major sources of error in quantifying the climate forcing effect of mineral aerosols. This stems from misrepresentation of the scattering phase function and the asymmetry parameter. Aerosol single-scattering computations based on non-spherical model particles are expected to reduce the shape-related errors and thus significantly improve the accuracy of radiative forcing simulations. Copyright © 2007 Royal Meteorological Society [source] Temperature dependence of heterogeneous uptake of N2O5 by ammonium sulfate aerosolATMOSPHERIC SCIENCE LETTERS, Issue 3 2009Paul T. Griffiths Abstract We present laboratory measurements of the dependence of the uptake coefficient , on temperature for removal of the NOx reservoir N2O5 by sub-micron aerosols containing ammonium sulfate and ammonium hydrogen sulfate. Uptake coefficients were measured over the range 263,303 K at 50% RH, which varied in the range 0.005,0.036. A simple negative dependence of uptake on temperature is observed for ammonium sulfate over this range, while the form of the temperature dependence of uptake by ammonium hydrogen sulfate is more complex. The results consolidate those of an earlier less definitive study of the temperature effect on N2O5 uptake. Copyright © 2009 Royal Meteorological Society [source] Die neue Tonhalle Düsseldorf , Beratung einer akustischen Quadratur des KreisesBAUPHYSIK, Issue 3 2006Klaus-Hendrik Lorenz-Kierakiewitz Dipl.-Phys. In diesem Aufsatz wird ein Überblick über die mannigfaltigen Facetten einer nichtalltäglichen raumakustischen Beratung gegeben: der kompletten Modernisierung der aufgrund Ihrer Form echobehafteten Tonhalle Düsseldorf, welche nach intensiver Planung und Beratung am 4. November 2005 mit großem Erfolg neu eröffnet werden konnte. Durch umfangreiche Labormessungen in einem akustischen Maßstabsmodell, einem reflexionsarmen Raum und einem Hallraum konnten hierzu spezielle Reflektorgeometrien, akustisch transparente Metallgewebe, eine minimal absorbierende Bestuhlung und nahezu geräuschlose architektonische Beleuchtungskörper entwickelt werden, womit nicht nur das frühere Echoproblem gelöst, sondern auch ein State of the Art-Konzertsaal mit hervorragender Akustik und beeindruckender Optik gebaut werden konnte. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) The new Tonhalle Düsseldorf , acoustically consulting of squaring a circle. In this paper an overview is given over the many sides of an unusual consulting project: the complete refurbishment of the Tonhalle Düsseldorf, which suffered formerly from severe echoes caused by its half-spherical shape. This concert hall could be re-opened on 4th November, 2005 with great success. By help of comprehensive laboratory measurements in an acoustical scale model, in a reflection-damped and in a reverberation chamber, specialized reflector geometries, acoustically transparent metal texture, minimally absorbing chairs and almost noiseless architectural lighting could be developed. With help of these measures, not only the former echo-problem could be solved, but also a state-of the-art concert hall with great acoustics and visual impression could be built. [source] Bhutani-based nomograms for the prediction of significant hyperbilirubinaemia using transcutaneous measurements of bilirubinACTA PAEDIATRICA, Issue 12 2009YA Bental Abstract Aim:, Prospectively establish the relationship between transcutaneous bilirubin (TcB) and total serum bilirubin (TSB), and develop nomograms similar to Bhutani's nomograms, based on our TcB data. Methods:, Our study sample was from a total population of 1069 infants, near term and term healthy newborns, admitted during 2.5 month period of the study. TSB was performed on all infants who were felt to be clinically jaundiced. Before obtaining the TSB, a TcB was performed (Jaundice Meter Minolta/Draeger JM-103). Measurements were performed on two sites: forehead and mid-sternum, and the mean of both measurements was calculated. Results:, A total of 1091 paired measurements were obtained from 628 infants. Linear regression showed a significant relation between TSB and TcB (R2 of 0.846). In multiple regression analysis, all independent variables studied, i.e. gestational age (or birthweight), age at sampling and ethnicity had a negligible influence on the relationship. We subsequently developed our local-nomograms of hour-specific mean TcB with 40, 75 and 95 percentile lines. Conclusions:, In our local settings and population, we found a reliable correlation between laboratory measurements of TSB and TcB. We were able to develop our local-Bhutani-based TcB nomograms for screening babies during hospital stay and pre-discharge for assessing the risk of hyperbilirubinaemia. [source] Plasma adiponectin in heart transplant recipientsCLINICAL TRANSPLANTATION, Issue 1 2009Pierre Ambrosi Abstract:, Background:, The association between plasma adiponectin and metabolic syndrome may be impaired in heart transplant recipients, since renal failure is frequent among these patients. Thus, we studied the relationship between metabolic syndrome and plasma adiponectin in transplanted heart recipients. Methods:, Ninety-five heart transplant recipients were prospectively included 8.3 ± 5.6 yr after transplantation in this cross-sectional study. All patients had physical examination, echocardiography or routine biennial coronary angiography, and laboratory measurements. Results:, Metabolic syndrome was found in 31% of these patients. Plasma adiponectin was significantly lower in patients with metabolic syndrome (12.5 ± 8.3 ,g/mL) than in patients without (16.7 ± 9.4 ,g/mL, p = 0.03). Adiponectin levels were usually in the normal or high range (< 4 ,g/mL in only two patients). Low creatinine clearance was associated with higher plasma adiponectin (R=,0.26, p = 0.01). Plasma adiponectin was not significantly different between the 28 patients with angiographic evidence of graft vasculopathy (13.9 ± 9.5 ,g/mL) and the 67 patients without (16.1 ± 9.1 ,g/mL, p = 0.3). Conclusions:, Contrasting with a high frequency of metabolic syndrome in these patients, adiponectin levels were usually in the normal or high range, probably as a consequence of renal failure. This suggests that adiponectin is not a major determinant for insulin resistance among these patients. [source] | |||||||||||||||||||