bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of phytoplankton community structure in the South China Sea in response to the East Asian aerosol input
Authors: Guo C. , Yu J. , Ho T.-Y. , Chen B. , Wang L. , Song S. , Kong L. , Liu H.
Published: July 2011

Abstract. Recent studies have regarded atmospheric deposition as an increasingly important source of nutrients to the ocean. The South China Sea (SCS), where aerosol loading is among the highest in the world, however, is poorly studied particularly on the in situ changes of phytoplankton community structures in response to atmospheric deposition. By conducting a series of microcosm bioassays at different hydrographical locations and simulating different aerosol event scales, we observed both positive and negative responses induced by the input of East Asia (EA) aerosol with high nitrogen (N) and trace metal contents, in terms of both community structure and physiological characteristics of phytoplankton. High levels of aerosol loading profoundly relieved phytoplankton nitrogen and trace metal limitations in SCS, and thus increased total phytoplankton biomass, enhanced their physiological indicators (e.g. photosynthetic efficiency) and shifted phytoplankton assemblages from being dominated by picoplankton to microphytoplanton, especially diatoms. However, under low levels of aerosol loading, the composition shift and biomass accumulation were not apparent, suggesting that the stimulation effects might be counterbalanced by enhanced grazing mortality indicated by increased abundance of protist grazers. Trace metal toxicity of the aerosols was also an important negative factor to phytoplankton growth, especially picocyanobacteria, implicated by the high copper (Cu) concentration in the microcosm that surpassed the toxicity threshold of marine cyanobacteria. Moreover, the magnitude and duration of the deposition event, as well as the hydrographical and trophic conditions of receiving waters are also important factors when predicting the influence of an aerosol deposition event. Our results demonstrated that the EA aerosol deposition events could profoundly change nutrient and phytoplankton dynamics in SCS and highlighted the need for achieving an accurate comprehension of atmospheric nutrient on the biogeochemical cycles of the oceans.
Development of an ensemble-adjoint optimization approach to derive uncertainties in net carbon fluxes
Authors: Ziehn T. , Scholze M. , Knorr W.
Published: July 2011

Abstract. Accurate modelling of the carbon cycle strongly depends on the parametrization of its underlying processes. The Carbon Cycle Data Assimilation System (CCDAS) can be used as an estimator algorithm to derive posterior parameter values and uncertainties for the Biosphere Energy Transfer and Hydrology scheme (BETHY). However, the simultaneous optimization of all process parameters can be quite challenging, due to the complexity and non-linearity of the BETHY model. Therefore, we propose a new overall concept, which uses ensemble runs and the adjoint optimization approach of CCDAS to derive the full probability density function (PDF) for posterior soil carbon parameters and the net carbon flux at the global scale. In this way, we only optimize those parameters, which can be constrained best by atmospheric carbon dioxide CO2) data. The prior uncertainties of the remaining parameters are included in a consistent way through ensemble runs, but are not constrained by data. The final PDF for the optimized parameters and the net carbon flux are then derived by superimposing the individual PDFs for each ensemble member. We find that the optimization with CCDAS converges much faster, due to the smaller number of processes involved. Moreover, it is more likely that we find the global minimum in the reduced parameter space.
Seasonal hydrologic prediction in the United States: understanding the role of initial hydrologic conditions and seasonal climate forecast skill
Authors: Shukla S. , Lettenmaier D. P.
Published: July 2011

Abstract. Seasonal hydrologic forecasts derive their skill from knowledge of initial hydrologic conditions (IHCs) and climate forecast skill (CFS) associated with seasonal climate outlooks. Depending on the type of hydrological regime and the season, the relative contributions of IHCs and CFS to seasonal hydrologic forecast skill vary. We seek to quantify these contributions on a relative basis across the Conterminous United States (CONUS). We constructed two experiments – Ensemble Streamflow Prediction (ESP) and reverse-ESP – to partition the contributions of the IHCs and CFS to overall forecast skill. In ESP hydrologic forecast skill is derived solely from knowledge of IHCs, whereas in reverse-ESP (second experiment), it is derived solely from atmospheric forcings (i.e. perfect CFS). Using the ratios of root mean square error (RMSE) in predicting cumulative runoff (CR) and mean monthly soil moisture (SM) of each experiment, we identify the variability of the relative contributions of the IHCs and CFS spatially throughout the year. We conclude that the IHCs generally have the strongest influence on the prediction of CR and SM at lead-1 (first month of the forecast period), beyond which CFS starts to have greater influence. Improvement in CFS alone will lead to better seasonal hydrologic forecast skill in most parts of the northeastern and southeastern US throughout the year and in the western US mainly during fall and winter months; whereas improvement in knowledge of the IHCs can potentially improve skill most in the western US during spring and summer months. We also observed that at short lead time (i.e. lead-1) contribution of the IHCs in SM forecasts is more extensive than in CR forecasts across the CONUS.
Open Source Procedure for Assessment of Loss using Global Earthquake Modelling software (OPAL)
Authors: Daniell J. E.
Published: July 2011

Abstract. This paper provides a comparison between Earthquake Loss Estimation (ELE) software packages and their application using an "Open Source Procedure for Assessment of Loss using Global Earthquake Modelling software" (OPAL). The OPAL procedure was created to provide a framework for optimisation of a Global Earthquake Modelling process through: 1. overview of current and new components of earthquake loss assessment (vulnerability, hazard, exposure, specific cost, and technology); 2. preliminary research, acquisition, and familiarisation for available ELE software packages; 3. assessment of these software packages in order to identify the advantages and disadvantages of the ELE methods used; and 4. loss analysis for a deterministic earthquake (Mw = 7.2) for the Zeytinburnu district, Istanbul, Turkey, by applying 3 software packages (2 new and 1 existing): a modified displacement-based method based on DBELA (Displacement Based Earthquake Loss Assessment, Crowley et al., 2006), a capacity spectrum based method HAZUS (HAZards United States, FEMA, USA, 2003) and the Norwegian HAZUS-based SELENA (SEismic Loss EstimatioN using a logic tree Approach, Lindholm et al., 2007) software which was adapted for use in order to compare the different processes needed for the production of damage, economic, and social loss estimates. The modified DBELA procedure was found to be more computationally expensive, yet had less variability, indicating the need for multi-tier approaches to global earthquake loss estimation. Similar systems planning and ELE software produced through the OPAL procedure can be applied to worldwide applications, given exposure data.
Comparative study on earthquake and ground based transmitter induced radiation belt electron precipitation at middle latitudes
Authors: Sidiropoulos N. F. , Anagnostopoulos G. , Rigas V.
Published: July 2011

Abstract. We examined (peak-to-background flux ratio p/b > 20) energetic electron bursts in the presence of VLF activity, as observed from the DEMETER satellite at low altitudes (~700 km). Our statistical analysis of measurements during two 6-month periods suggests that: (a) the powerful transmitter NWC causes the strongest effects on the inner radiation belts in comparison with other ground-based VLF transmitters, (b) the NWC transmitter was responsible for only ~1.5 % of total electron bursts examined during the 6-month period (1 July 2008 to 31 December 2008), (c) VLF transmitter-related electron bursts are accompanied by the presence of a narrow band emission centered at the radiating frequency emission, whereas the earthquake-related electron bursts are accompanied by the presence of broadband emissions from a few kHz to >20 KHz, (d) daytime events are less preferable than nighttime events, but this asymmetry was found to be less evident when the powerful transmitter NWC was turned off and (d) seismic activity most probably dominated the electromagnetic interactions producing the electron precipitation at middle latitudes. The results of this study support the proposal that the detection of radiation belt electron precipitation, besides other kinds of studies, is a useful tool for earthquake prediction research.
ENSO-correlated fluctuations in ocean bottom pressure and wind-stress curl in the North Pacific
Authors: Chambers D. P.
Published: July 2011

Abstract. We examine the magnitude of ENSO-correlated variations in wind-stress curl and ocean bottom pressure in the North Pacific between 1992 until 2010, using satellite observations and model output. Our analysis indicates that while there are significant fluctuations correlated with some El Niño and La Niña events, the correlation is still relatively low. Moreover, the ENSO-correlated variability explains only 50 % of the non-seasonal, low-frequency variance. There are significant residual fluctuations in both wind-stress curl and ocean bottom pressure in the region with periods of 4-years and longer. One such fluctuation began in late 2002 and has been observed by the Gravity Recovery and Climate Experiment (GRACE). Even after accounting for ENSO variations, there is a significant trend in ocean bottom pressure in the region, equivalent to 0.7 ± 0.3 cm yr−1 of sea level from January 2003 until December 2008, which is confirmed with steric-corrected altimetry. Although this low-frequency fluctuation does not appear in an ocean model, we show that the winds used to force the model have a significantly reduced trend that is inconsistent with satellite observations over the same time period.
Secondary Relaxation inside the Glass
Authors: Sharifi Soheil , Mashaiekhy Asl Jahanbakhsh
Published: July 2011

The physical properties of the glass depend on the procedure used to produce the glass. In particular, if the glass is obtained through the variation of external thermodynamic parameters, the specific way in which the parameters are varied (thermodynamic history) has influence on the final properties. In this work, we studied the effect of thermodynamic history on secondary relaxation inside the glassy state on different molecular glass forming, namely, PPGE(poly[(phenyl glycidyl ether)-co-formaldehyde]), 1,18-bis (p methoxyphenyl) cyclohexane (BMPC), poly(propylene glycol)—(PPG400), phenolphthalein-dimethyl-ether(PDE), Poly(vinyl acetate) (PVAc), and poly(bisphenol A-co-epichlorohydrin) glycidyl end-capped (DGEBA). We found secondary relaxation change with thermodynamic history and depends on the value of the activation volume which activation entropy of secondary relaxation inside the glassy state. Also, we found most of the JG secondary relaxation change with thermodynamic history and most of the Non-JG secondary relaxation are not sensitive.
PROBES, POPULATIONS, SAMPLES, MEASUREMENTS AND RELATIONS IN STEREOLOGY
Authors: Dehoff Robert T
Published: July 2011

This summary paper provides an overview of the content of stereology. The typical problem at hand centers around some three dimensional object that has an internal structure that determines its function, performance, or response. To understand and quantify the geometry of that structure it is necessary to probe it with geometric entities: points, lines, planes volumes, etc. Meaningful results are obtained only if the set of probes chosen for use in the assessment is drawn uniformly from the population of such probes for the structure as a whole. This requires an understanding of the population of each kind of probe. Interaction of the probes with the structure produce geometric events which are the focus of stereological measurements. In almost all applications the measurement that is made is a simple count of the number of these events. Rigorous application of these requirements for sample design produce unbiased estimates of geometric properties of features in the structure no matter how complex are the features or what their arrangement in space. It is this assumption-free characteristic of the methodology that makes it a powerful tool for characterizing the internal structure of three dimensional objects.
EFFICIENT AND UNBIASED TOOLS FOR QUANTITATING LEYDIG AND SERTOLI CELLS IN THE TESTIS FROM TESTES BIOPSIES
Authors: Petersen Peter M , Giwercman Aleksander , Gundersen Hans Jørgen G , Pakkenberg Bente
Published: July 2011

The possibility of obtaining reliable estimates of the total number of Sertoli and Leydig cells from biopsies by use of the optical fractionator method was tested. The total number of Sertoli and Leydig cells was 522x106 (CV = 0.27) and 89x106 (CV = 0.34), respectively, when sampling in the entire testis while the mean total number of Sertoli and Leydig cells, sampling from biopsies, was 494x106 and 103x106, respectively, statistically a non-significant difference. The present study indicated that total number of testicular cells can be estimated stereologically from the number of cells in biopsies if the sizes of testis and the biopsy can be assessed with adequate precision.
STEREOLOGICAL ANALYSIS OF THE COCHLEAR NUCLEI OF MONKEY (MACACA FASCICULARIS) AFTER DEAFFERENTATION
Authors: Insausti Ana M , Insausti Ricardo , Cruz-Orive Luis M , Manrique Manuel
Published: July 2011

The cochlear nuclei (CN) in the brainstem receive the input signals from the inner ear through the cochlear nerve, and transmit these signals to higher auditory centres. A variety of lesions of the cochlear nerve cause deafness. As reported in the literature, artificial removal of auditive input, or 'deafferentation', induces structural alterations in the CN. The purpose of this study was to estimate a number of relevant stereological parameters of the CN in control and deafferented Macaca fascicularis monkeys.
ON THE VARIANCE OF LOCAL STEREOLOGICAL VOLUME ESTIMATORS
Authors: Jensen Eva B Vedel
Published: July 2011

In the present paper, the variance of local stereological volume estimators is studied. For isotropic designs, the variance depends on the shape of the body under study and the choice of reference point. It can be expressed in terms of an equivalent star body. For a collection of triaxial ellipsoids the variance is determined by simulation. The problem of estimating particle size distributions from central sections through the particles is also discussed.
QUANTIFICATION OF BIOFILMS IN MULTI-SPECTRAL DIGITAL1 VOLUMES FROM CONFOCAL LASER-SCANNING MICROSCOPES
Authors: Rodenacker Karsten , Brühl Andreas , Hausner Martina , Kühn Martin , Liebscher Volkmar , Wagner Michael , Winkler Gerhard , Wuertz Stefan
Published: July 2011

Populations of bacteria in sludge flocs and biofilm marked by fluorescence marked with fluorescent probes are digitised with a confocal laser scanning microscope. These data are used to analyse the microbial community structure, to obtain information on the localisation of specific bacterial groups and to examine gene expression. This information is urgently required for an in-depth understanding of the function and, more generally, the microbial ecology of biofilms. Methods derived from quantitative image analysis are applied to digitised data from confocal laser scanning microscopes to obtain quantitative descriptions of volumetric, topological (and topographical) properties of different compartments of the components under research. In addition to free-moving flocs, also biofilms attached to a substratum in an experimental environment are analysed. Growth form as well as interaction of components are quantitatively described. Classical measurements of volume and intensity (shape, distribution) and distance dependent interaction measurements using methods from mathematical morphology are performed. Mainly image (volume) processing methods are outlined. Segmented volumes are globally and individually (in terms of 3Dconnected components) measured and used for distance mapping transform as well as for estimation of geodesic distances from the substrate. All transformations are applied on the 3D data set. Resulting distance distributions are quantified and related to information on the identity and activity of the probe-identified bacteria.
ACCURACY OF ESTIMATES OF VOLUME FRACTION
Authors: Chia Joanne , Baddeley Adrian
Published: July 2011

When estimating a volume fraction VV from point count fractions PP using Delesse's principle VV = PP, very little information on the accuracy of the estimator can be obtained from the basic theory of stereology. Existing methods for quantifying the variability of PP are mainly large-sample approximations such as Cochran's formula for the variance of a ratio. Cruz-Orive proposed an alternative method, but this requires statistical assumptions to be made on the point counts P, that do not hold in general. We introduce two alternative methods for quantifying the variability of PP, namely the bootstrap method and explicit statistical modelling of the bivariate distribution. The bootstrap method requires few statistical assumptions about the point counts but requires large sample size. The explicit statistical modelling method does make assumptions, but they can be checked directly from the data. To explore this approach, we propose a statistical model, the Type I Bivariate Binomial (BVB) distribution to model the pairs of count data (P, P). We show how to fit the BVB model to the data and how to assess the goodness-of-fit of this model. A formula for the variance of PP under the BVB model is also derived. The three approaches are compared in their application to nine example data sets taken from macroscopic sections of cerebral hemispheres of selected domesticated animals. The BVB model appears to be a good fit to these data sets. Implications for stereological estimation are discussed.
NEPHRON NUMBER IN THE OFFSPRING OF RATS FED A LOW PROTEIN DIET DURING PREGNANCY
Authors: Zimanyi Monika A , Bertram John F , Black Jane M
Published: July 2011

In experimental studies it has been shown that intrauterine growth retardation and reduced kidney growth during development are associated with significant decreases in nephron endowment. However, the results of previous studies may be inaccurate as nephron counts were obtained using a maceration technique, which can lead to breakdown of glomeruli, and other potentially biased techniques. In the present study, the total number of glomeruli (and thereby nephrons) in the offspring of rats fed a low (9%) or normal (20%) protein diet during pregnancy were estimated using a physical disector/fractionator technique. The offspring of rats fed a low protein diet had a significantly lower birth weight than rats fed a normal protein diet, their kidneys were smaller and they contained 30% fewer nephrons (20,386 ± 4,818 in the low protein diet vs. 28,731 ± 3,290 in the control rats). Our results, obtained using an unbiased stereological technique confirm previous findings that administration of a low protein diet during pregnancy results in reduced nephron endowment in the offspring.
MIB-1, AgNOR AND DNA DISTRIBUTION PARAMETERS AND THEIR PROGNOSTIC VALUE IN NEUROENDOCRINE TUMOURS OF THE LUNG
Authors: Jütting Uta , Gais Peter , Rodenacker Karsten , Böhm Joachim , Höfler Heinz
Published: July 2011

One of the most important questions in clinical routine is to find out patients with good or worse prognosis to apply an optimal therapy scheme for each patient. In this study 58 patients with different neuroendocrine tumours of the lung were investigated. Histological sections were prepared with different stainings (MIB-1, AgNOR, Feulgen). By means of high resolution image cytometry stereological parameters were derived which are indicators for proliferation, ploidy and kinetics of the tumours. Cox regression analysis was calculated to test the significance of the parameters with regard to prognosis. The best parameter was MIB-1 which can easily be applied as a clinical standard staining and measurement.
FRACTAL ANALYSIS OF TRABECULAR BONE: A STANDARDISED METHODOLOGY
Authors: Parkinson Ian , Fazzalari Nick
Published: July 2011

A standardised methodology for the fractal analysis of histological sections of trabecular bone has been established. A modified box counting method has been developed for use on a PC based image analyser (Quantimet 500MC, Leica Cambridge). The effect of image analyser settings, magnification, image orientation and threshold levels, was determined. Also, the range of scale over which trabecular bone is effectively fractal was determined and a method formulated to objectively calculate more than one fractal dimension from the modified Richardson plot. The results show that magnification, image orientation and threshold settings have little effect on the estimate of fractal dimension. Trabecular bone has a lower limit below which it is not fractal (λ<25 μm) and the upper limit is 4250 μm. There are three distinct fractal dimensions for trabecular bone (sectional fractals), with magnitudes greater than 1.0 and less than 2.0. It has been shown that trabecular bone is effectively fractal over a defined range of scale. Also, within this range, there is more than 1 fractal dimension, describing spatial structural entities. Fractal analysis is a model independent method for describing a complex multifaceted structure, which can be adapted for the study of other biological systems. This may be at the cell, tissue or organ level and compliments conventional histomorphometric and stereological techniques.
THREE-DIMENSIONAL OBSERVATIONS ON THICK BIOLOGICAL SPECIMENS BY HIGH VOLTAGE ELECTRON MICROSCOPY
Authors: Nagata Tetsuji
Published: July 2011

Thick biological specimens prepared as whole mount cultured cells or thick sections from embedded tissues were stained with histochemical reactions, such as thiamine pyrophosphatase, glucose-6-phosphatase, cytochrome oxidase, acid phosphatase, DAB reactions and radioautography, to observe 3-D ultrastructures of cell organelles producing stereo-pairs by high voltage electron microscopy at accerelating voltages of 400-1000 kV. The organelles demonstrated were Golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes, peroxisomes, pinocytotic vesicles and incorporations of radioactive compounds. As the results, those cell organelles were observed 3- dimensionally and the relative relationships between these organelles were demonstrated.
ASSESSMENT OF PARTICLE PACKING CHARACTERISTICS AT INTERFACES BY SPACE SYSTEM
Authors: Stroeven Piet , Stroeven Martijn
Published: July 2011

Interest in material structure has been raised by upgrading of cementitious systems. Computer-simulation of material structure has been pursued so far by using random generators. Such systems were successfully applied for estimating global properties. Realistic estimation of structure-sensitive properties, however requires a more appropriate simulation of material structure. The SPACE (Software Package for the Assessment of Compositional Evolution) system has been developed for that purpose. It incorporates particle interaction and gravitational influences, which are typical for the 'natural' processes underlying the formation of material structure in the production stage. The capabilities are discussed of the two computersimulation methods for generating structural information relevant for either structure-insensitive, or structure-sensitive properties in bulk and in the interfacial transition zone (ITZ). The structural information will deal with composition and configuration of the material, respectively. The use of random generatorbased (RG) systems is demonstrated not justified when dealing with structure-sensitive problems.
CAVEAT ON THE ERROR ANALYSIS FOR STEREOLOGICAL ESTIMATES
Authors: Yang Zhengwei , Zhang Rendong , Wen Xiaohong , Huang Anpei
Published: July 2011

It is frequently asked that how big a sample size, or how much measurement, is needed to achieve an accuratestereological estimate. The observed total error of a stereological estimate arises from individual difference (i.e. i ter-animal / organ difference or biological variation) and intra-individual variation (or the stereological error). Statistical methods for error analysis familiar to most biological researchers are based on independent random sampling, however systematic random sampling, which is usually more efficient, is almost always performed in practice. A number of methods for error analysis were utilized in a number of model and actual studies in this paper to demonstrate from a practical point of view the pros and cons of different error analytical methods. Assumption of independence for a systematic sampling will result in overestimation of the stereological error as shown by the studies. A simple and practical approach for error analysis as recommended in this paper is to divide the systematic sample from an organ into two systematic sub-samples, regard them as two independent sub-samples and then compare the difference between the two sub-sample means.
EXPERIMENTAL EVALUATION OF STEREOLOGICAL METHODS FOR DETERMINING 3D GRAIN SIZE AND TOPOLOGICAL DISTRIBUTIONS
Authors: Liu Guoquan , Yu Haibo
Published: July 2011

The conventional serial sectioning analysis and a set of modern stereological methods, including disector, selector, point-sampled intercepts, point-sampled area, and their combinations, have been used in this paper to measure the grain size, grain size distribution, topological parameters and their distributions in a spacefilling single-phase grain structure of steel. The results from different methods are compared and used to evaluate the methods quantitatively, based on which some suggestions will be given for selection of experimental methods in materials stereology research.
PREDICTION OF THE EXTREMAL SHAPE FACTOR OF SPHEROIDAL PARTICLES
Authors: Hlubinka Daniel , Beneš Viktor
Published: July 2011

In the stereological unfolding problem for spheroidal particles the extremal shape factor is predicted. The theory of extreme values has been used to show that extremes of the planar shape factor of particle sections tend to the same limit distribution as extremes of the original shape factor for both the conditional and marginal distribution. Attention is then paid to the extreme shape factor conditioned by the particle size. Normalizing constants are evaluated for a parametric model and the numerical procedure is tested on real data from metallography.
GEODESIC RECONSTRUCTION, SADDLE ZONES & HIERARCHICAL SEGMENTATION
Authors: Beucher Serge
Published: July 2011

The morphological reconstruction based on geodesic operators, is a powerful tool in mathematical morphology. The general definition of this reconstruction supposes the use of a marker function f which is not necessarily related to the function g to be built. However, this paper deals with operations where the marker function is defined from given characteristic regions of the initial function f, as it is the case, for instance, for the extrema (maxima or minima) but also for the saddle zones. Firstly, we show that the intuitive definition of a saddle zone is not easy to handle, especially when digitised images are involved. However, some of these saddle zones (regional ones also called overflow zones) can be defined, this definition providing a simple algorithm to extract them. The second part of the paper is devoted to the use of these overflow zones as markers in image reconstruction. This reconstruction provides a new function which exhibits a new hierarchy of extrema. This hierarchy is equivalent to the hierarchy produced by the so-called waterfall algorithm. We explain why the waterfall algorithm can be achieved by performing a watershed transform of the function reconstructed by its initial watershed lines. Finally, some examples of use of this hierarchical segmentation are described.
IMAGE ANALYSIS DEDICATED TO POLYMER INJECTION MOLDING
Authors: Garcia David , Courbebaisse Guy , Jourlin Michel
Published: July 2011

This work follows the general framework of polymer injection moulding simulation whose objectives are the mastering of the injection moulding process. The models of numerical simulation make it possible to predict the propagation of the molten polymer during the filling phase from the positioning of one point of injection or more. The objective of this paper is to propose a particular way to optimize the geometry of mold cavity in accordance with physical laws. A direct correlation is pointed out between geometric parameters issued from skeleton transformation and Hausdorff's distance and results provided by implementation of a classical model based on the Hele-Shaw equations which are currently used in the main computer codes of polymer injection.
EVALUATING THE EULER-POINCARÉ CHARACTERISTIC OF A SET USING A SPATIAL TESSELLATION
Authors: Jernot Jean-Paul , Jouannot-Chesney Patricia , Joul Christian Lantué
Published: July 2011

A new formula is established to evaluate the Euler-Poincaré characteristic of a polyconvex subset X in Rd starting only from measurements of X in the cells of a tessellation. Simplifications occur when X is a union of cells of the tessellation, leading to another formula that unifies and extends several classical digitization results.
RENAL GLOMERULAR NUMBER AND SIZE IN AUSTRALIAN ABORIGINES, AFRICAN AMERICANS AND WHITE POPULATIONS FROM THE SAME LOCATIONS: A PRELIMINARY REPORT
Authors: Bertram John F , Johnson Kelli , Hughson Michael D , Hoy Wendy E
Published: July 2011

End stage renal disease is a major health problem for Australian Aborigines and African Americans. Abnormally enlarged glomeruli are commonly observed in biopsies from Aborigines and African Americans and may represent a compensatory hypertrophic response to reduced nephron endowment. We have commenced a study examining glomerular number and size, and their associations in Australian Aborigines and whites, and US African Americans and whites. Kidneys at autopsy are perfusion-fixed and subsampled for stereological estimation of total glomerular number (Nglom; using the physical disector/fractionator combination), and mean renal corpuscle (Vcorp) and glomerular volume (Vglom). Kidneys from 58 people have been studied to date with ages ranging from newborn to 84 years. Preliminary findings are: (1) an almost 9-fold range in Nglom (from 210,332 to 1,825,380) with a mean of 762,302; (2) Nglom decreased with age in adult life (p = 0.014); (3) Vcorp varied 19-fold in the series and 5.5-fold in adults; (4) Vglom was inversely correlated with Nglom (p = 0.004); (5) total renal corpuscle volume (Nglom × Vcorp) ranged by a factor of 13.2; (6) kidney weight was correlated with body surface area (BSA) at all ages (p < 0.001); (7) BSA-corrected kidney weight did not vary with age, it ranged from 47 g/m2 to 175 g/m2, a 3.7 fold difference, with an average of 92 ± 25 g/m2. These preliminary results have revealed several new and important correlations. No racial differences in glomerular number or size have yet been identified, but with greater sample sizes such differences may be revealed.
DOMAIN SIZE DISTRIBUTION OF Y-TZP NANO-PARTICLES USING XRD AND HRTEM
Authors: Boulc'h Florence , Schouler Marie-Claude , Donnadieu Patricia , Chaix Jean-Marc , Djurado Elisabeth
Published: July 2011

Yttria doped nanocrystalline zirconia powder was prepared by spray-pyrolysis technique. Powder crystallized into tetragonal form, as dense and compositionally homogeneous polycrystalline spheres. X-Ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) have been used in order to characterize the mean size and the size distribution of crystalline domains. An average size of 6 nm was calculated by Scherrer formula from X-Ray diffraction pattern. The domain size, determined by analysis method developed by Hytch from HRTEM observations, ranges from 5 to 22 nm with a main population around the value 12 nm. Limits and complementary nature of XRD and HRTEM methods are discussed.
SPATIAL REPARTITION OF CURRENT FLUCTUATIONS IN A SCANNING TUNNELING MICROSCOPE
Authors: Lagoute Jerome , Zambelli Tomaso , Martin Stephane , Gauthier Sebastien
Published: July 2011

Scanning Tunneling Microscopy (STM) is a technique where the surface topography of a conducting sample is probed by a scanning metallic tip. The tip-to-surface distance is controlled by monitoring the electronic tunneling current between the two metals. The aim of this work is to extend the temporal range of this instrument by characterising the time fluctuations of this current on different surfaces. The current noise power spectral density is dominated by a characteristic 1/f component, the physical origin of which is not yet clearly identified, despite a number of investigations. A new I-V preamplifier was developed in order to characterise these fluctuations of the tunnelling current and to obtain images of their spatial repartition. It is observed that their intensity is correlated with some topographical features. This information can be used to get insights on the physical phenomena involved that are not accessible by the usual STM set-up, which is limited to low frequencies.
EFFECT OF HISTOMORPHOMETRIC PARAMETERS ON COMPRESSION STRENGTH OF VERTEBRAL BODIES
Authors: Gadek Artur , Wojnar Leszek , Czerviński Edward
Published: July 2011

Computer aided image analysis was applied to elaborate an automatic method of histomorphometric analysis of trabecular bone samples. Transverse sections of decalcified vertebral bodies were examined using optical microscopy and digital image acquisition system. Further analysis was done by means of a general purpose image analysis package. The same algorithm was applied to all the images tested, thus enabling obtainment of objective and repeatable results. High efficiency in measurements and evaluation of parameters not accessible for manual methods makes this method an interesting alternative for classical histomorphometric analysis. The results obtained demonstrated that assessment of bone mineral density is not sufficient for evaluation of compression strength of vertebral bodies. In contrast, mechanical properties correlate well with histomorphometric parameters. As a consequence it was postulated that compression strength of vertebral bodies is controlled by trabecular structure rather than bone mineral density.
ON THE ESTIMATION OF DISTANCE DISTRIBUTION FUNCTIONS FOR POINT PROCESSES AND RANDOM SETS
Authors: Stoyan Dietrich , Stoyan Helga , Tscheschel André , Mattfeldt Torsten
Published: July 2011

This paper discusses various estimators for the nearest neighbour distance distribution function D of a stationary point process and for the quadratic contact distribution function Hq of a stationary random closed set. It recommends the use of Hanisch's estimator of D, which is of Horvitz-Thompson type, and the minussampling estimator of Hq. This recommendation is based on simulations for Poisson processes and Boolean models.
WAVELET TRANSFORM AND LIP MODEL
Authors: Courbebaisse Guy , Trunde Frederic , Jourlin Michel
Published: July 2011

The Fourier transform is well suited to the study of stationary functions. Yet, it is superseded by the Wavelet transform for the powerful characterizations of function features such as singularities. On the other hand, the LIP (Logarithmic Image Processing) model is a mathematical framework developed by Jourlin and Pinoli, dedicated to the representation and processing of gray tones images called hereafter logarithmic images. This mathematically well defined model, comprising a Fourier Transform "of its own", provides an effective tool for the representation of images obtained by transmitted light, such as microscope images. This paper presents a Wavelet transform within the LIP framework, with preservation of the classical Wavelet Transform properties. We show that the fast computation algorithm due to Mallat can be easily used. An application is given for the detection of crests.
SEMIAUTOMATIC DETECTION OF TUMORAL ZONE
Authors: Zagrouba Ezzeddine , Barhoumi Walid
Published: July 2011

This paper describes a robust method based on the cooperation of fuzzy classification and regions segmentation algorithms, in order to detect the tumoral zone in the brain Magnetic Resonance Imaging (MRI). On one hand, the classification in fuzzy sets is done by the Fuzzy C-Means algorithm (FCM), where a study of its different parameters and its complexity has been previously realised, which led us to improve it. On the other hand, the segmentation in regions is obtained by an hierarchical method through adaptive thresholding. Then, an operator expert selects a germ in the tumoral zone, and the class containing the sick zone is localised in return for the FCM algorithm. Finally, the superposition of the two partitions of the image will determine the sick zone. The originality of our approach is the parallel exploitation of different types of information in the image by the cooperation of two complementary approaches. This allows us to carry out a pertinent approach for the detection of sick zone in MRI images.
GRANULOMETRIC MAPS FROM HIGH RESOLUTION SATELLITE IMAGES
Authors: Mering Catherine , Chopin Franck
Published: July 2011

A new method of land cover mapping from satellite images using granulometric analysis is presented here. Discontinuous landscapes such as steppian bushes of semi arid regions and recently growing urban settlements are especially concerned by this study. Spatial organisations of the land cover are quantified by means of the size distribution analysis of the land cover units extracted from high resolution remotely sensed images. A granulometric map is built by automatic classification of every pixel of the image according to the granulometric density inside a sliding neighbourhood. Granulometric mapping brings some advantages over traditional thematic mapping by remote sensing by focusing on fine spatial events and small changes in one peculiar category of the landscape.
MATHEMATICAL MORPHOLOGY IN THE CIELAB SPACE
Authors: Hanbury Allan , Serra Jean
Published: July 2011

The use of mathematical morphology in the CIE L*a*b* colour space is discussed. It is possible to impose a total order on the colour vectors in this space by using a weighting function and lexicographical order. An order analogous to one by colour saturation is suggested by making use of a weighting function based on an electrostatic potential. This weighting function assigns a lower weight to colour vectors near the colours with maximum chroma, and higher weights to colour vectors near the lightness axis. The use of morphological operators with the colour vector order imposed by this function is demonstrated. Finally, a top-hat operator making use of the Euclidean colour distance in the L*a*b* space is introduced.
VIDEOGRAMMETRIC RECONSTRUCTION APPLIED TO VOLCANOLOGY: PERSPECTIVES FOR A NEW MEASUREMENT TECHNIQUE IN VOLCANO MONITORING
Authors: Cecchi Emmanuelle , Lavest Jean Marc , Vries Benjamin Van Wyk De
Published: July 2011

This article deals with videogrammetric reconstruction of volcanic structures. As a first step, the method is tested in laboratory. The objective is to reconstruct small sand and plaster cones, analogous to volcanoes, that deform with time. The initial stage consists in modelling the sensor (internal parameters) and calculating its orientation and position in space, using a multi-view calibration method. In practice two sets of views are taken: a first one around a calibration target and a second one around the studied object. Both sets are combined in the calibration software to simultaneously compute the internal parameters modelling the sensor, and the external parameters giving the spatial location of each view around the cone. Following this first stage, a N-view reconstruction process is carried out. The principle is as follows: an initial 3D model of the cone is created and then iteratively deformed to fit the real object. The deformation of the meshed model is based on a texture coherence criterion. At present, this reconstruction method and its precision are being validated at laboratory scale. The objective will be then to follow analogue model deformation with time using successive reconstructions. In the future, the method will be applied to real volcanic structures. Modifications of the initial code will certainly be required, however excellent reconstruction accuracy, valuable simplicity and flexibility of the technique are expected, compared to classic stereophotogrammetric techniques used in volcanology.
A QUANTITATIVE METHOD FOR ANALYSING 3-D BRANCHING IN EMBRYONIC KIDNEYS: DEVELOPMENT OF A TECHNIQUE AND PRELIMINARY DATA
Authors: Fricout Gabriel , Cullen-McEwen Luise A , Harper Ian S , Jeulin Dominique , Bertram John F
Published: July 2011

The normal human adult kidney contains between 300,000 and 1 million nephrons (the functional units of the kidney). Nephrons develop at the tips of the branching ureteric duct, and therefore ureteric duct branching morphogenesis is critical for normal kidney development. Current methods for analysing ureteric branching are mostly qualitative and those quantitative methods that do exist do not account for the 3- dimensional (3D) shape of the ureteric "tree". We have developed a method for measuring the total length of the ureteric tree in 3D. This method is described and preliminary data are presented. The algorithm allows for performing a semi-automatic segmentation of a set of grey level confocal images and an automatic skeletonisation of the resulting binary object. Measurements of length are automatically obtained, and numbers of branch points are manually counted. The final representation can be reconstructed by means of 3D volume rendering software, providing a fully rotating 3D perspective of the skeletonised tree, making it possible to identify and accurately measure branch lengths. Preliminary data shows the total length estimates obtained with the technique to be highly reproducible. Repeat estimates of total tree length vary by just 1-2%. We will now use this technique to further define the growth of the ureteric tree in vitro, under both normal culture conditions, and in the presence of various levels of specific molecules suspected of regulating ureteric growth. The data obtained will provide fundamental information on the development of renal architecture, as well as the regulation of nephron number.
IMAGE ANALYSIS CHARACTERIZATION OF HIGHLY ORIENTED FREEZE-DRYING POROUS MATERIALS
Authors: Blacher Silvia , Maquet Véronique , Jérôme Robert , Pirard Jean-Paul
Published: July 2011

Image analysis has been used as a potential tool for the characterization of the texture of ultramacroporous foams prepared by freeze-drying. It has been shown that this technique actually provides valuable information on the structure of this kind of material. Image analysis of SEM micrographs of transverse sections at two different magnifications gave information on both the macroporosity (10 μm < width < 100 μm) and ultramacroporosity (width > 100 μm). Moreover, the foam anisotropy has been determined by image analysis of longitudinal sections.
THE MORPHOLOGICAL PYRAMID AND ITS APPLICATIONS TO REMOTE SENSING: MULTIRESOLUTION DATA ANALYSIS AND FEATURES EXTRACTION
Authors: Florence Laporterie , Guy Flouzat , Olivier Amram
Published: July 2011

In remote sensing, sensors are more and more numerous, and their spatial resolution is higher and higher. Thus, the availability of a quick and accurate characterisation of the increasing amount of data is now a quite important issue. This paper deals with an approach combining a pyramidal algorithm and mathematical morphology to study the physiographic characteristics of terrestrial ecosystems. Our pyramidal strategy involves first morphological filters, then extraction at each level of resolution of well-known landscapes features. The approach is applied to a digitised aerial photograph representing an heterogeneous landscape of orchards and forests along the Garonne river (France). This example, simulating very high spatial resolution imagery, highlights the influence of the parameters of the pyramid according to the spatial properties of the studied patterns. It is shown that, the morphological pyramid approach is a promising attempt for multi-level features extraction by modelling geometrical relevant parameters.
A NEW HIGH RESOLUTION OPTICAL METHOD FOR OBTAINING THE TOPOGRAPHY OF FRACTURE SURFACES IN ROCKS
Authors: Ogilvie Steven , Isakov Evgeny , Taylor Colin , Glover Paul
Published: July 2011

Surface roughness plays a major role in the movement of fluids through fracture systems. Fracture surface profiling is necessary to tune the properties of numerical fractures required in fluid flow modelling to those of real rock fractures. This is achieved using a variety of (i) mechanical and (ii) optical techniques. Stylus profilometry is a popularly used mechanical method and can measure surface heights with high precision, but only gives a good horizontal resolution in one direction on the fracture plane. This method is also expensive and simultaneous coverage of the surface is not possible. Here, we describe the development of an optical method which images cast copies of rough rock fractures using in-house developed hardware and image analysis software (OptiProf™) that incorporates image improvement and noise suppression features. This technique images at high resolutions, 15-200 μm for imaged areas of 10 × 7.5 mm and 100 × 133 mm, respectively and a similar vertical resolution (15 μm) for a maximum topography of 4 mm. It uses in-house developed hardware and image analysis (OptiProf™) software and is cheap and non-destructive, providing continuous coverage of the fracture surface. The fracture models are covered with dye and fluid thicknesses above the rough surfaces converted into topographies using the Lambert-Beer Law. The dye is calibrated using 2 devices with accurately known thickness; (i) a polycarbonate tile with wells of different depths and (ii) a wedge-shaped vial made from silica glass. The data from each of the two surfaces can be combined to provide an aperture map of the fracture for the scenario where the surfaces touch at a single point or any greater mean aperture. The topography and aperture maps are used to provide data for the generation of synthetic fractures, tuned to the original fracture and used in numerical flow modelling.
TEXTURAL FRACTOGRAPHY
Authors: Lauschmann Hynek , Ráček Ondřej , Tůma Michal , Nedbal Ivan
Published: July 2011

The reconstitution of the history of a fatigue process is based on the knowledge of any correspondences between the morphology of the crack surface and the velocity of the crack growth (crack growth rate - CGR). The textural fractography is oriented to mezoscopic SEM magnifications (30 to 500x). Images contain complicated textures without distinct borders. The aim is to find any characteristics of this texture, which correlate with CGR. Pre-processing of images is necessary to obtain a homogeneous texture. Three methods of textural analysis have been developed and realized as computational programs: the method based on the spectral structure of the image, the method based on a Gibbs random field (GRF) model, and the method based on the idealization of light objects into a fibre process. In order to extract and analyze the fibre process, special methods - tracing fibres and a database-oriented analysis of a fibre process - have been developed.