Accurate Background Research Articles

Evidenzbasierte Empfehlungen der „European League against Rheumatism” zur Diagnose und Therapie der Hand-Arthrose

Hand osteoarthritis (HOA) has a high prevalence and occurs either as a single entity or as part of a generalised osteoarthritis. To improve diagnosis and management of HOA in daily practice, the EULAR Standing Committee for International Clinical Studies Including Therapeutics (ESCISIT) has published recommendations which are based on expert opinions and a systematic literature search. The typical clinical signs and symptoms are well known; nevertheless, for accurate diagnosis further background knowledge is necessary. The 10 EULAR recommendations given for the diagnosis of HOA summarise risk factors, demographic aspects, signs and symptoms, subgroups, radiographic changes and laboratory tests as well as differential diagnosis. The management of HOA requires a patient-orientated strategy with a multidisciplinary approach. 11 EULAR recommendations focus on pharmacological therapies, occupational and physiotherapy as well as patient education and surgical intervention. Efficacy and safety of local steroids, paracetamol, non-steroidal anti-inflammatory drugs as well as symptomatic slow-acting drugs for osteoarthritis (SYSADOA) are discussed.

Dynamical mass of a star cluster in M 83: a test of fibre-fed multi-object spectroscopy

Aims. We obtained VLT/FLAMES+UVES high-resolution, fibre-fed spectroscopy of five young massive clusters (YMCs) in M 83 (NGC 5236). This forms the basis of a pilot study testing the feasibility of using fibre-fed spectroscopy to measure the velocity dispersions of several clusters simultaneously, in order to determine their dynamical masses. In principle, this reduces the telescope time required to obtain a statistically significant sample of dynamical cluster masses. These can be used to assess the long-term survivability of YMCs by comparing their dynamical and photometric masses, which are necessary to ascertain the potential evolution of YMCs into second-generation globular clusters. Methods. We adopted two methods for determining the velocity dispersion of the star clusters: cross-correlating the cluster spectrum with the template spectra and minimising a χ 2 value between the cluster spectrum and the broadened template spectra. We also considered both red giant and red supergiant template stars. Cluster 805 in M 83 (following the notation of Larsen) was chosen as a control to test the reliability of the results obtained by this observational method, through a comparison with the results obtained from a standard echelle VLT/UVES spectrum obtained by Larsen & Richtler. Results. We find no dependence of the velocity dispersions measured for a cluster on the choice of red giant versus red supergiant templates, nor on the method adopted. However, we do find that the standard deviation of the results obtained with only one method may underestimate the true uncertainty. We measure a velocity dispersion of σlos = 10.2 ± 1. 1k m s −1 for cluster 805 from our fibrefed spectroscopy. This is in excellent agreement with the velocity dispersion of σlos = 10.6 ± 1. 4k m s −1 determined from the standard echelle UVES spectrum of cluster 805. Our FLAMES+UVES velocity dispersion measurement gives Mvir = (6.6 ± 1.7) × 10 5 M� , consistent with previous results. This value of the virial mass is a factor of ∼3 greater than the cluster’s photometric mass, indicating a lack of virial equilibrium. However, based on its effective star formation efficiency, the cluster is likely to virialise, and may survive for a Hubble time, in the absence of external disruptive forces. Unfortunately, our observations of the other M 83 star clusters have insufficient signal-to-noise ratios to determine robust cluster velocity dispersions. Conclusions. We find that reliable velocity dispersions can be determined from high-resolution, fibre-fed spectroscopy. The advantages of observing several clusters simultaneously outweighs the difficulty of accurate galaxy background subtraction, providing that the targets are chosen to provide sufficient signal-to-noise ratios, and are much brighter than the galaxy background.

In-situ trace element analysis of monazite and other fine-grained accessory minerals by EPMA

Trace element analysis of high Z accessory phases by electron probe micro-analysis offers unique access to data unattainable by other analytical techniques, but also presents great challenges. The intimate relationships between beam conditions (voltage, current), spatial resolution, precision, and spectral complexity require the careful examination of all analytical parameters and their consequences, at a level commensurate with the sensitivity of the desired analysis. The high REE and actinide content, and resulting high Z of monazite, allows high direct analytical resolution (below 500 nm at 10 kV, depending on the realized beam diameter) due to limited electron range, but the high concentration of these elements will also produce significant fluorescence at a distance. The use of high accelerating potential in an effort to improve counting statistics is injudicious in most cases, as direct analytical resolution decreases, and high overvoltage on REEs and Th in monazite results in efficient production of energetic ionizing radiation (L-series) capable of fluorescing elements of interest, or interfering elements at remarkable distances (at least several 10 s of microns from the beam). Boundary fluorescence is a very significant problem in trace element analysis and in geochronologic analysis of monazite, as grains are commonly complex, with micro-domains that differ considerably in composition (especially Th/REE). In such instances, a 15 kV beam can produce fluorescence at a distance, leading to errors of 10 s of ppm within 5 μm of a compositional boundary. For trace element analysis, effects such as background curvature and minor interferences can result in very large errors, 50% or more for curvature alone for concentrations at or below 100 ppm. Strong background curvature is observed for all makes and varieties of spectrometers in the Pb-M region. In addition, for REE and actinide bearing phases such as monazite, the wavelength regions available for background determination are very limited, requiring routine, high-precision scanning and regression modeling to determine reasonably accurate background intensities. Two-point background interpolation methods are inappropriate for high sensitivity analysis in all cases. Without a direct means to verify the accuracy of low concentration analyses, great attention must be paid to analytical protocol and very detailed spectral analysis. The use of consistency standards to monitor changes is important, but caution must be exercised in the use of secondary “age” standards in the case of monazite EPMA because systematic error can result in cancellation effects when concentrations of both parent and daughter are proportionally incorrect. In all cases, caution in interpretation and integration of all available information is necessary if the potential of the method is to be realized.

Determination of Cd in urine by cloud point extraction–tungsten coil atomic absorption spectrometry

Cadmium concentrations in human urine are typically at or below the 1 μg L −1 level, so only a handful of techniques may be appropriate for this application. These include sophisticated methods such as graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry. While tungsten coil atomic absorption spectrometry is a simpler and less expensive technique, its practical detection limits often prohibit the detection of Cd in normal urine samples. In addition, the nature of the urine matrix often necessitates accurate background correction techniques, which would add expense and complexity to the tungsten coil instrument. This manuscript describes a cloud point extraction method that reduces matrix interference while preconcentrating Cd by a factor of 15. Ammonium pyrrolidinedithiocarbamate and Triton X-114 are used as complexing agent and surfactant, respectively, in the extraction procedure. Triton X-114 forms an extractant coacervate surfactant-rich phase that is denser than water, so the aqueous supernatant is easily removed leaving the metal-containing surfactant layer intact. A 25 μL aliquot of this preconcentrated sample is placed directly onto the tungsten coil for analysis. The cloud point extraction procedure allows for simple background correction based either on the measurement of absorption at a nearby wavelength, or measurement of absorption at a time in the atomization step immediately prior to the onset of the Cd signal. Seven human urine samples are analyzed by this technique and the results are compared to those found by the inductively coupled plasma mass spectrometry analysis of the same samples performed at a different institution. The limit of detection for Cd in urine is 5 ng L −1 for cloud point extraction tungsten coil atomic absorption spectrometry. The accuracy of the method is determined with a standard reference material ( toxic metals in freeze-dried urine) and the determined values agree with the reported levels at the 95% confidence level.

Photometric properties and scaling relations of early-type Brightest Cluster Galaxies

We investigate the photometric properties of the early-type Brightest Cluster Galaxies (BCGs) using a carefully selected sample of 85 BCGs from the C4 cluster catalogue with a redshift of less than 0.1. We perform accurate background subtractions and surface photometry for these BCGs to 25 mag arcsec−2 in the Sloan r band. By quantitatively analysing the gradient of the Petrosian profiles of BCGs, we find that a large fraction of BCGs have extended stellar envelopes in their outskirts; more luminous BCGs tend to have more extended stellar haloes that are likely to be connected with mergers. A comparison sample of elliptical galaxies was chosen with similar apparent magnitude and redshift ranges, for which the same photometric analysis procedure is applied. We find that BCGs have steeper size–luminosity (R∝Lα) and Faber–Jackson (L∝σβ) relations than the bulk of early-type galaxies. Furthermore, the power-law indices (α and β) in these relations increase as the isophotal limits become deeper. For isophotal limits from 22 to 25 mag arcsec−2, BCGs are usually larger than the bulk of early-type galaxies, and a large fraction (∼49 per cent) of BCGs have discy isophotal shapes. The differences in the scaling relations are consistent with a scenario where the dynamical structure and formation route of BCGs may be different from the bulk of early-type galaxies; in particular dry (dissipationless) mergers may play a more important role in their formation. We highlight several possible dry merger candidates in our sample.

Total flux density radio observations as a tool for understanding AGN behaviour

A wealth of information on the properties of jets in Active Galactic Nuclei (AGNs) can be derived from total flux density observations at high radio frequencies. This includes, for example, the Doppler factor, the Lorentz factor, and the viewing angle of the jet. We have earlier calculated these parameters for a sample of ∼80 sources of different AGN types using almost 20 years of 22 and 37 GHz data from Metsahovi Radio Observatory. We have now gathered data for an additional ten years, and studied the long term characteristic variability time scales of a large sample of AGNs using the first order structure function, the discrete autocorrelation function and the Lomb-Scargle periodogram. Some of the results will be presented in this paper. We also stress the importance of long term observations of AGNs, the main reason for this being misinterpretations of source properties due to insufficient time coverage. Only a few observing epochs will too easily lead to incorrect conclusions about variability, continuum spectra, and the general detectability of the source, not to mention the exclusion of interesting objects from further studies. This is particularly important when considering, for example, the Planck satellite for which the quality of the main mission product, the accurate cosmic microwave background anisotropy maps, depends heavily on the elimination of foreground sources such as AGNs.

C2-C6 Background Hydrocarbon Concentrations Monitored at a Roof Top and Green Park Site, in Dublin City Centre

A 5 week monitoring campaign was carried out in Dublin City centre, to establish which site gave a more accurate background city centre estimation: a roof-top or green field site. This background represented a conservative estimate of HC exposure in Dublin City centre, useful for quantifying health effects related to this form of pollution and also for establishing a local background relative to the four surrounding main roads when the wind direction is travelling towards each road with the background receptor upwind. Over the entire monitoring campaign, the lowest concentrations and relative standard deviations were observed at the green field site, regardless of time of day or meteorological effects.

Effective vehicle detection technique for traffic surveillance systems

Moving object detection is one of the key technologies for intelligent video monitoring systems. For real-time detection of moving object in the surveillance scene, the general and simple method is based on background image difference. However, it requires the accurate current background image and the approach for automatic background updating along with the illumination variance is difficult to design and implement. This limits its applications. To solve the above problem, a new self-adaptive background approximating and updating algorithm based on optical flow theory is presented for the traffic surveillance scene in this paper. To detect the moving regions of interest in the scene, the difference image between the current frame and the updating background is first obtained by using a color image difference model, and then a self-adaptive thresholding segmentation method for moving object detection based on the Gaussian model is developed and implemented. Moreover, an effective shadow-eliminating algorithm based on contour information and color features is developed. Experimental results demonstrate that the proposed background updating method can update the background exactly and rapidly along with the variance of illumination, the self-adaptive thresholding segmentation method based on the Gaussian model can extract the moving object regions accurately and completely, and the shadow can be eliminated accurately. This is the foundation for further objects recognition and understanding.

ChandraTemperature Profiles for a Sample of Nearby Relaxed Galaxy Clusters

We present Chandra gas temperature profiles at large radii for a sample of 13 nearby, relaxed galaxy clusters and groups, which includes A133, A262, A383, A478, A907, A1413, A1795, A1991, A2029, A2390, MKW4, RXJ1159+5531, and USGC S152. The sample covers a range of average temperatures from 1 to 10 keV. The clusters are selected from the archive or observed by us to have sufficient exposures and off-center area coverage to enable accurate background subtraction and reach the temperature accuracy of better than 20-30% at least to r=0.4-0.5 r_180, and for the three best clusters, to 0.6-0.7 r_180. For all clusters, we find cool gas in the cores, outside of which the temperature reaches a peak at r =~ 0.15 r_180 and then declines to ~0.5 of its peak value at r =~ 0.5 r_180. When the profiles are scaled by the cluster average temperature (excluding cool cores) and the estimated virial radius, they show large scatter at small radii, but remarkable similarity at r>0.1-0.2 r_180 for all but one cluster (A2390). Our results are in good agreement with previous measurements from ASCA by Markevitch et al. and from Beppo-SAX by DeGrandi & Molendi. Four clusters have recent XMM-Newton temperature profiles, two of which agree with our results, and we discuss reasons for disagreement for the other two. The overall shape of temperature profiles at large radii is reproduced in recent cosmological simulations.

Seismic angle tomography

One of the main challenges in seismic imaging is the estimation of sufficiently accurate background velocity models in the presence of complex geology. In this paper we show the use of a differential semblance in angle or DSA (Symes and Carazzone, 1991; Brandsberg-Dahl et al., 2003) misfit function to perform ray-based angle tomography on PP and its extension to PS reflection events. This measure is optimal as it is the only measure that depends smoothly on the velocity model.

A contribution to creating groups of trees for forest valuation

During the construction of model logging costs for valuation of forest stands, by accident I found out differences between some species included in the groups of tree species. Differences within the groups of species may cause errors in logging costs of some species, for example with hornbeam, all species of linden, all species of rowans and horse chestnut. With the help of simple calculations it was proved that the differences could be very large, that they were more than forty per cent, it means they were significant. On the basis of my further research it is envisaged to increase the number of groups of trees from 13 to 16. The purpose is to give the most accurate background to make up a model of logging costs. In the second step it is expected that the model can provide the results for more or fewer groups of trees more easily if statistical methods are used. But this problem is not a part of this paper.

Contributions to precision and accuracy of monazite microprobe ages

We examine the factors controlling accuracy and precision of monazite microprobe ages, using a JEOL 733 Superprobe equipped with 4 PET crystals, and both 1-atm gas flow Ar X-ray detectors and sealed Xe X-ray detectors. Multiple PET crystals allow for simultaneous determination of Pb concentration on up to 3 detectors, and the effects of different detector gases on spectral form can be addressed. Numerous factors in the X-ray production, detection, and counting sequence affect spectral form, including: choice of accelerating voltage, changes in d -spacing of the diffraction crystal, use of X-ray collimation slits, and type of detector gas. The energy difference between Ar K α X-rays and Xe L α X-rays results in, for 1-atm Ar detectors, escape peaks of second-order LREE L line X-rays that cannot be filtered using differential mode PHA. The second-order LREE energies are passed to the counter and produce, for a 140 mm Rowland circle, several problematic interferences in the Pb region of a monazite wavelength-dispersive (WD) spectrum. WD monazite spectra produced with Xe detectors are free from second-order LREE interferences in the Pb region; escape peaks of the second-order LREE are filterable with differential mode PHA if Xe detectors are employed. Silicon, Ca, Y, Ce, P, Th, U, and Pb (2 spectrometers) are measured as part of the monazite microprobe dating protocol; ±2σ variations in elements fixed for ZAF corrections do not affect the age outside of analytical uncertainty. Th M α, U M β, and Pb M α are the analyzed lines of the age components. Corrections for interference of Th M ζ1,2 and Y L γ2,3 on Pb M α are significant, but can be done precisely, and reduce the precision of the M α analysis by a trivially small amount. Th M γ, M 3- N 4, and M 5- P 3 interferences on U M β can be corrected, as well, but Th M 5 and M 4 absorption edges in high-Th samples make estimation of U M β background problematic. Background fits for U M β peaks show that linear vs. exponential fits for U M β do not, in general, produce statistically significant differences in microprobe ages. However, linear vs. exponential background fits for Pb M α peaks do produce significantly different ages, most likely because of (1) low Pb concentrations relative to U; (2) Th M ζ1 interference on backgrounds between Th M ζ1 and Pb M β; and (3) S K α and K β interference in S-bearing monazite. For 6-min analyses (3 min peak, 3 min background) at 25 keV and 200 nA, 1σ Pb precisions are approximately 3–4% at 1700 ppm and 9.5% at 750 ppm; at 15 keV, precision decreases by roughly 25% of the 25 keV value. These precisions are constant for fixed current, analysis time, and concentration, but the statistical precision of distinct populations of monazite grains (domains) is a function of the total number of analyses within the domain. Instrumental errors (current measurement, dead time, pulse shift, d -spacing change) add 1–10% to random errors, but errors caused by pulse shift and d -spacing changes can be accounted for and corrected. Decreasing accelerating voltage from 25 to 15 keV decreases ZAF correction factors by as much as 50% relative, but replicate age analyses of Trebilcock monazite at 15 and 25 keV are statistically indistinguishable. Grain orientation, miscalculated background intensity, uncorrected interferences, and surface effects also introduce systematic errors. Accurate background interpolation and interference correction reduces systematic error to approximately 5–20% in addition to random (counting) error. Microprobe ages (~420 Ma) and 208Pb/232Th SIMS ages (~430 Ma) of monazite from Vermont are in agreement to within ~10 m.y. The discrepancy between U-Th-total Pb microprobe ages and 208Pb/232Th ages is removed when the high background measurement for Pb M α is shifted to the short-wavelength side of Pb M β, removing a possible Th M ζ1 interference.

A comparative study of three different methods for the sequential extraction of heavy metals in soil

Three different methods for the sequential extraction of heavy metals from soil (viz those of Tessier et al. (A. Tessier, P.G. Campbell and N. Bisson (1979). Anal. Chem., 51, 844.), Sposito et al. (G. Sposito, L.J. Lund and A.C. Chang (1989). Soil. Sci. Soc. Am. J., 46, 260.) and Mann and Ritchie (S.S. Mann and G.S.P. Ritchie (1993). Aust. J. Soil Res., 31, 255.)) were examined in terms of the distribution of Cu, Zn and Pb in the soil phases and the bioavailability of these elements in soil. To this end, several samples of soils polluted with metals from a copper mine were fractionated by using the three studied methods and analyzed by atomic absorption spectrometry. The results revealed differences in extraction efficiency among the methods due to the extractant used, or its concentration, and to the soil/solution ratio. The three methods were found to provide accurate heavy metal background contents. However, the method of Tessier et al. is to be preferred for quantifying increased levels of heavy metals on account of its high extraction power.

Multiscale imaging of complex structures from multifold wide-aperture seismic data by frequency-domain full-waveform tomography: application to a thrust belt

An application of full-waveform tomography to dense onshore wide-aperture seismic data recorded in a complex geological setting (thrust belt) is presented. The waveform modelling and tomography are implemented in the frequency domain. The modelling part is solved with a finite-difference method applied to the visco-acoustic wave equation. The inversion is based on a local gradient method. Only the P-wave velocity is involved in the inversion. The inversion is applied iteratively to discrete frequency components by proceeding from low to high frequencies. This defines a multiscale imaging in the sense that high wavenumbers are progressively incorporated in images. The linearized waveform tomography requires an accurate starting velocity model that has been developed by first-arrival traveltime tomography. After specific pre-processing of the data, 16 frequency components ranging between 5.4 and 20 Hz were inverted. Ten iterations were computed per frequency component leading to 160 tomographic models. The waveform tomography has successfully imaged southwest-dipping structures previously identified from other geophysical data as being associated with high-resistivity bodies. The relevance of the tomographic images is locally demonstrated by comparison of a velocity–depth function extracted from the waveform tomography models with a coincident vertical seismic profiling (VSP) log available on the profile. Moreover, comparison between observed and synthetic seismograms computed in the (starting) traveltime and waveform tomography models demonstrates unambiguously that the waveform tomography successfully predicts for wide-angle reflections from southwest-dipping geological structures. This study demonstrates that the combination of first-arrival traveltime and frequency-domain full-waveform tomographies applied to dense wide-aperture seismic data is a promising approach to quantitative imaging of complex geological structures. Indeed, wide-aperture acquisition geometries offer the opportunity to develop an accurate background velocity model for the subsequent waveform tomography. This is critical, because the building of the macromodel remains an open question when only near-vertical reflection data are considered.

Development of background reduced Fresnel phase zone plate

In study of hot and dense plasma, a high spatial resolution (a few microns) x-ray imaging is very important to observe these plasmas. The Fresnel phase zone plate (FPZP) consists of alternately material and transparent circular annuli placed concentrically, which image x rays using diffraction x rays from all annuli. FPZP have imaged 4.7–4.77 keV x rays with 2.2 μm spatial resolution. However FPZP has a problem that background level is comparable to signal level. In subtraction of background, the error of 10% is caused. For the accurate background subtraction, we designed new FPZP, which consist of three β layers of a transparent zone and two material zones. The new design FPZP parameters (thickness of material zones, each zone width) have been optimized, and in that optimum design signal-to-background ratio is 4 times better than conventional two layers FPZP.

Detection of cloud‐affected AIRS channels using an adjacent‐pixel approach

AbstractHigh‐spectral‐resolution infrared sounders such as the Atmospheric InfraRed Sounder (AIRS), flying on the National Aeronautics and Space Administration Earth Observing System (EOS) Aqua satellite, provide information about vertical temperature and humidity structure that is potentially useful for data assimilation and numerical weather prediction. Tropospheric channels from infrared sounders are frequently affected by cloud. The methods currently used operationally to account for cloud effects are screening to eliminate cloud‐contaminated data and cloud‐clearing. For either approach, it is important to determine which channels peak sufficiently above the cloud so that they are not contaminated. Depending on the sounding, different combinations of channels are cloud‐contaminated, thus making cloud detection difficult.This paper proposes a new method of identifying clear or unaffected channels using adjacent pixels. Unlike other proposed or implemented methods, this approach does not rely heavily on having accurate background information about the atmospheric state or estimates of its error. The method also does not make any assumptions about cloud spectral properties. Instead, it assumes that clouds will produce adjacent‐pixel variability. The approach requires an estimate of clear‐scene adjacent‐pixel homogeneity that can be obtained with real data.We apply the methodology to simulated AIRS data using Monte Carlo experiments. We then apply the algorithm to real AIRS data and use brightness temperature departure statistics as an independent check for residual cloud contamination. We also make qualitative comparisons with cloud properties derived from the EOS Aqua Moderate‐Resolution Imaging Spectroradiometer instrument. Copyright © 2004 Royal Meteorological Society

WMAP constraints on varying α and the promise of reionization

We present up-to-date constraints on the value of the fine-structure constant at the epoch of decoupling from the recent observations made by the Wilkinson Microwave Anisotropy Probe (WMAP) satellite. In the framework of models we considered, a positive (negative) variation of the value of α at decoupling with respect to the present-day value is now bounded to be smaller than 2% (6%) at 95% confidence level. We point out that the existence of an early reionization epoch as suggested by the above measurements will, when more accurate cosmic microwave background polarization data is available, lead to considerably tighter constraints. The so-called ‘reionization bump’, in particular, will be extremely useful for this purpose. We find that the tightest possible constraint on α is about 0.1% using CMB data alone—tighter constraints will require further (non-CMB) priors.

LAKE EUTROPHICATION MODEL BASED ON THE IMPACT OF THE ZOOPLANKTON COMMUNITY ON PHYTOPLANKTON SUCCESSION

To estimate the long-term effects of ecosystem-manipulating lake restoration methods such as biomanipulation, we need a numerical model which can predict the succession of plankton community with sufficient accuracy. An accurate numerical model can be prepared based on an accurate data background. In this sense, two series of mesocosm (outdoor open-air pond) experiments that mimicked conditions in shallow and eutrophic water ecosystem were performed to clarify the effects of the zooplankton community on phytoplankton succession quantitatively. The experiments were carried out in both summer and winter periods. The results revealed that three types of zooplankton, namely rotifers, copepods, and cladocerans, have different effects on phytoplankton succession. Rotifers did not graze blue-green algae. Cladocerans suppress the growth of phytoplankton even for some blue-green algae effectively by their predation. The results of these experiments suggest that the amount of crustaceans, i.e., copepods and cladocerans, should be increased for the successful enforcement of biomanipulation. A model based on these quantitative outcomes, and its prediction of a biomanipulation for an eutrophic shallow lake is also mentioned.

The effects of bushfires on hydrological processes using a paired-catchment analysis

Several problems associated with capturing the effects of bushfires on hydrological processes in the Goulburn River catchment (6810 km2), Hunter Valley, Australia are investigated using a paired-catchment analysis. It is suggested, first, that the within-year-missing data, as defined in this paper, need to be examined carefully when using the double-mass curve of annual total discharge in a paired-catchment analysis. Second, in order to provide an accurate precipitation background, which is one of the most important prerequisites for a paired-catchment analysis, the use of annual average precipitation is strongly recommended together with annual total precipitation when there are large amounts of within-year-missing data. Third, caution is needed in comparing multi-year average precipitation and streamflow data before and after the fire when the data series is not statistically long enough, since the average values for precipitation and streamflow over a different number of years may produce completely contrasting results. Fourth, the analysis of the flow duration curve, which is another useful technique in paired-catchment analysis, needs to be interpreted from the precipitation duration curve. This is because the change of flow duration curve can be caused either from the change of precipitation or the fire. Fifth, the change in streamflow, calculated by subtracting the average streamflow for the non-fire years from the observed streamflow for the years in which fires occurred, is not an efficient way of capturing the fire effects. The problem associated with this approach is not just that the streamflow is strongly dependent on rainfall, as reported elsewhere, but also, it can lead to misinterpretation using the hydrograph when the average streamflow in non-fire years is close to the average streamflow in fire years.

New constraints on varying α

We present a summary of recent constraints on the value of the fine-structure constant at the epoch of decoupling from the recent observations made by the Wilkinson microwave anisotropy probe (WMAP) satellite. Within the set of models considered, a variation of the value of α at decoupling with respect to the present-day value is now bounded to be smaller than 2% (6%) at 95% confidence level. We point out that the existence of an early reionization epoch as suggested by the above measurements will, when more accurate cosmic microwave background polarization data are available, lead to considerably tighter constraints. We find that the tightest possible constraint on α is about 0.1% using CMB data alone – tighter constraints will require further (non-CMB) priors.