bluuebunny/crossref_metadata_2025 huggingface dataset:
A Modular approach to Customer Satisfaction in Relation to Service Quality
Authors: Jayasundara Chaminda Chiran
Published: July 2011

Continuous improvement of customer (user) service is essential to successful development of business in today’s highly competitive, dynamic and complex business environment. There is no exception from it for philanthropic areas including libraries. Thus, this paper reviews the existing literature related to customer satisfaction in relation to service quality to identify the research issues and implications to establish further research avenues in the field. The study revealed that there is a consensus among service marketing researchers on the causal sequence/order of the concepts of customer satisfaction and service quality. Through conceptual improvement and empirical findings of past studies, most researchers have concurred on the fact that quality judgments cause satisfaction, leading to the finding on service quality being the antecedent of customer satisfaction. The formation of satisfaction in relation to service quality is generally based upon some significant theories identified in the literature and it recognised two dominant theoretical paradigms, disconfirmation and performance-only, which can be duly used for modelling customer satisfaction through the service quality perspective in organisations, enabling them to perform possible customer-led service quality evaluations. Secondly, the review more closely examined the potentiality of the prevalent service quality and customer satisfaction models which have been applied in the field of library and information services, such as SERVQUAL, SERVPREF and LibQUAL, understand the customer satisfaction process in the context of service quality. These models were, however, not adequately qualified to confirm their strong applicability for the modelling of the satisfaction process in libraries. Finally, the review concluded with fourteen research issues and their implications relating to library services in demonstrating the void of the prevailing body of knowledge, for new research avenues. Keywords: Customer satisfaction; User satisfaction; Service quality; User services; Library marketing; User modelling DOI: http://dx.doi.org/10.4038/jula.v15i1.3188 Journal of the University Librarians’ Association of Sri Lanka, Vol.15, Issue 1, June 2011; 23-82
A Comparison of the Requirements of University Library Quality Assurance System with Internationally Recognized ISO 9001:2000 and ISO 9001:2008 Quality Management Systems
Authors: Dissanayake Harshani NK
Published: July 2011

Providing a quality service has become a must in the library and information science sector today. The readers expect an effective and efficient library service from the library staff. Therefore providing a customer oriented service has become a challenge to the librarians and information professionals. The University Grants Commission has initiated a Quality Assurance System for all the faculties and the academic libraries of the Universities under the World Bank project, Improving Relevance and Quality of Undergraduate Education (IRQUE). The quality management systems (QMS) ISO 9001:2000 and ISO 9001:2008 are internationally recognized Quality Management Systems. They have been successfully implemented in some Sri Lankan libraries to provide an effective service to the library users. A comparison of the requirements of the University Library Quality Assurance System and the two international standards is carried out in this study. Key words: Quality Management System; ISO 9001:2000; ISO 9001:2008; Academic Libraries; Sri Lanka DOI: http://dx.doi.org/10.4038/jula.v15i1.3189 Journal of the University Librarians’ Association of Sri Lanka, Vol.15, Issue 1, June 2011; 83-97
A Comparative Assessment of Material Use in Three Medical Libraries in Sri Lanka
Authors: Peterson DT , Jayasuriya Sumana
Published: July 2011

Assessing the use of library materials justifies the extent the library fulfills its main objective of providing information to its users. Furthermore, assessing the use of library materials is considered as a method of measuring library performance. The objective of this study was to find the usage of library collections held by the medical libraries of University of Colombo, Kelaniya and Sri Jayewardenepura and to recommend measures that could be taken to enhance their collection use. Suitable indicators to assess collection use were selected from performance indicators developed by the International Federation of Library Associations and Institutions (IFLA), International Organization for Standardization (ISO), and American Library Association (ALA). The collection use was assessed following the methodologies given for each indicator. Results showed that the Medical library of University of Kelaniya had the highest usage of the collection, followed by the Medical library of University of Colombo and the Medical library of University of Sri Jayawardenepura. The analysis of library services, loans and acquisitions policies of the three libraries showed that the quality and quantity of the library collection, library opening hours, loans policy and seating capacity within the library affect the use of the library’s collection. It can be recommended from this study that amending its loans policy to allow borrowing of two lending books at a time per user at the Medical library of University of Colombo and amending its collection development policy at Medical Library of University of Sri Jayewardenepura would result in higher use of library materials. The Medical libraries of Kelaniya and Sri Jayewardenepura should consider increasing opening hours. All three libraries assessed should adopt suitable weeding policies in order to maintain up to date collections. Key words: Collection use; Performance measurement; Medical libraries DOI: http://dx.doi.org/10.4038/jula.v15i1.3190Journal of the University Librarians’ Association of Sri Lanka, Vol.15, Issue 1, June 2011; 98-113
Safer Technique for Passing Abdominal Trochar
Authors: Fysh Thomas , Ferguson Douglas
Published: July 2011

Many closed surgical drainage systems are delivered through the abdominal wall with a trochar [...]
Stem growth of woody species at the Nkuhlu exclosures, Kruger National Park: 2006–2010
Authors: Scogings Peter F.
Published: July 2011

An important aspect of managing African conservation areas involves understanding how large herbivores affect woody plant growth. Yet, data on growth rates of woody species in savannas are scarce, despite its critical importance for developing models to guide ecosystem management. What effect do browsing and season have on woody stem growth? Assuming no growth happens in the dry season, browsing should reduce stem growth in the wet season only. Secondly, do functional species groups differ in stem growth? For example, assuming fine-leaved, spiny species’ growth is not compromised by carbon-based chemical defences, they should grow faster than broad-leaved, chemically defended species. Dendrometers were fixed at 20 cm in height on the main stems of 244 random plants of six woody species in three plots (all large herbivores excluded, partial exclusion, and control) and observed from late 2006 to early 2010. Average monthly increment (AMI) per dendrometer and season (dry, wet) was calculated and the interaction between plot and season tested per species, controlling for initial stem girth. AMIs of Combretum apiculatum, Dichrostachys cinerea and Grewia flavescens were zero in the dry season, whilst those of Acacia exuvialis, Acacia grandicornuta and Euclea divinorum were either positive or negative in the dry season. Wet-season AMI of D. cinerea and dry-season AMI of G. flavescens tended to be reduced by browser exclusion. Net AMI (sum of the seasonal AMIs) was tested per species, but results suggested that only D. cinerea tended to be affected by browser exclusion. The results also suggested that stem radial growth of some fast-growing species is more prone to reduction by browser exclusion than the growth of other species, potentially reducing their competitiveness and increasing their risk of extirpation. Finally, the usefulness of grouping woody species into simple functional groups (e.g. fine-leaved vs. broad-leaved) for ecosystem management purposes in savannas requires further consideration. Conservation implications: Growth rates of woody plants are important parameters in savanna models, but data are scarce. Monitoring dendrometers in manipulative situations over several years can help fill that gap. Results of such studies can be used to identify species prone to high risk of extirpation.
Simplices in the Euclidean Ball
Authors: Fradelizi Matthieu , Paouris Grigoris , Schütt Carsten
Published: July 2011

We establish some inequalities for the second moment

of a convex body K under various assumptions on the position of K.
Left Invariant Einstein–Randers Metrics on Compact Lie Groups
Authors: Wang Hui , Deng Shaoqiang
Published: July 2011

In this paper we study left invariant Einstein–Randers metrics on compact Lie groups. First, we give a method to construct left invariant non-Riemannian Einstein–Randers metrics on a compact Lie group, using the Zermelo navigation data. Then we prove that this gives a complete classification of left invariant Einstein–Randers metrics on compact simple Lie groups with the underlying Riemannian metric naturally reductive. Further, we completely determine the identity component of the group of isometries for this type of metrics on simple groups. Finally, we study some geometric properties of such metrics. In particular, we give the formulae of geodesics and flag curvature of such metrics.
3-D Numerical Simulations of Biofilm Flows
Authors: Chen Chen , Ren Mingming , Srinivansan Ashok , Wang Qi
Published: July 2011

We study the biofilm-flow interaction resulting in biofilm growth and deformation in a water channel in a 3-D setting using the phase field model developed recently. In this biofilm model, the biofilm made up of the EPS, bacteria and solvent is tracked using a biofilm volume fraction which vanishes outside the biofilm region. The interface between the biofilm and the solvent is marked by the zero level surface of the volume fraction measured from the biofilm to the solvent. The growth of the biofilm and the solvent-biofilm interaction with the top nutrient feeding condition is simulated in the viscous regime (growth regime) of the biofilm-solvent mixture flow. In quiescent flows, the model predicts growth patterns consistent with experimental findings for single or multiple adjacent biofilm colonies, in which the known mushroom shape growth pattern is obtained. Shear induced deformation in biofilms is simulated in a shear cell, providing a viable numerical evidence for using simulation tool to study biofilm growth and interaction dynamics in aqueous environment.
Spectral Direction Splitting Schemes for the Incompressible Navier-Stokes Equations
Authors: Chen Lizhen , Shen Jie , Xu Chuanju
Published: July 2011

We propose and analyze spectral direction splitting schemes for the incompressible Navier-Stokes equations. The schemes combine a Legendre-spectral method for the spatial discretization and a pressure-stabilization/direction splitting scheme for the temporal discretization, leading to a sequence of one-dimensional elliptic equations at each time step while preserving the same order of accuracy as the usual pressure-stabilization schemes. We prove that these schemes are unconditionally stable, and present numerical results which demonstrate the stability, accuracy, and efficiency of the proposed methods.
The impact of orbital sampling, monthly averaging and vertical resolution on climate chemistry model evaluation with satellite observations
Authors: Aghedo A. M. , Bowman K. W. , Shindell D. T. , Faluvegi G.
Published: July 2011

Abstract. Ensemble climate model simulations used for the Intergovernmental Panel on Climate Change (IPCC) assessments have become important tools for exploring the response of the Earth System to changes in anthropogenic and natural forcings. The systematic evaluation of these models through global satellite observations is a critical step in assessing the uncertainty of climate change projections. This paper presents the technical steps required for using nadir sun-synchronous infrared satellite observations for multi-model evaluation and the uncertainties associated with each step. This is motivated by need to use satellite observations to evaluate climate models. We quantified the implications of the effect of satellite orbit and spatial coverage, the effect of variations in vertical sensitivity as quantified by the observation operator and the impact of averaging the operators for use with monthly-mean model output. We calculated these biases in ozone, carbon monoxide, atmospheric temperature and water vapour by using the output from two global chemistry climate models (ECHAM5-MOZ and GISS-PUCCINI) and the observations from the Tropospheric Emission Spectrometer (TES) instrument on board the NASA-Aura satellite from January 2005 to December 2008. The results show that sampling and monthly averaging of the observation operators produce zonal-mean biases of less than ±3 % for ozone and carbon monoxide throughout the entire troposphere in both models. Water vapour sampling zonal-mean biases were also within the insignificant range of ±3 % (that is ±0.14 g kg−1) in both models. Sampling led to a temperature zonal-mean bias of ±0.3 K over the tropical and mid-latitudes in both models, and up to −1.4 K over the boundary layer in the higher latitudes. Using the monthly average of temperature and water vapour operators lead to large biases over the boundary layer in the southern-hemispheric higher latitudes and in the upper troposphere, respectively. Up to 8 % bias was calculated in the upper troposphere water vapour due to monthly-mean operators, which may impact the detection of water vapour feedback in response to global warming. Our results reveal the importance of using the averaging kernel and the a priori profiles to account for the limited vertical resolution and clouds of a nadir observation during model application. Neglecting the observation operators resulted in large biases, which are more than 60 % for ozone, ±30 % for carbon monoxide, and range between −1.5 K and 5 K for atmospheric temperature, and between −60 % and 100 % for water vapour.
Model HULIS compounds in nanoaerosol clusters – investigations of surface tension and aggregate formation using molecular dynamics simulations
Authors: Hede T. , Li X. , Leck C. , Tu Y. , Ågren H.
Published: July 2011

Abstract. Cloud condensation nuclei act as cores for water vapour condensation, and their composition and chemical properties may enhance or depress the ability for droplet growth. In this study we use molecular dynamics simulations to show that model humic-like substances (HULIS) in systems containing 10 000 water molecules mimic experimental data well referring to reduction of surface tension. The model HULIS compounds investigated in this study are cis-pinonic acid (CPA), pinic acid (PAD) and pinonaldehyde (PAL). The structural properties examined show the ability for the model HULIS compounds to aggregate inside the nanoaerosol clusters.
Change of iron species and iron solubility in Asian dust during the long-range transport from western China to Japan
Authors: Takahashi Y. , Higashi M. , Furukawa T. , Mitsunobu S.
Published: July 2011

Abstract. In the North Pacific, transport and deposition of mineral dust from Asia appear to be one of major sources of iron which can regulate growth of phytoplankton in the ocean. In this process, it is essential to identify chemical species of iron contained in Asian dust, because bioavailability of iron in the ocean is strongly influenced by the solubility of iron, which in turn is dependent on iron species in the dust. Here, we report that clay minerals (illite and chlorite) in the dusts near the source (western China) are transformed into ferrihydrite by atmospheric chemical processes during their long-range transport to eastern China and Japan based on the speciation by X-ray absorption fine structure (XAFS) and other methods such as X-ray diffraction and chemical extraction. Moreover, it was found that iron in the dust after the transport becomes more soluble in our leaching experiments conducted for 24 h compared with those for initial dusts possibly due to the formation of ferrihydrite in the atmosphere. Our findings suggested that ferrihydrite secondarily formed during the transport is an important source of soluble iron species, which can be more soluble than clay minerals initially contained in the mineral dust such as illite and chlorite.
Determination of land surface heat fluxes over heterogeneous landscape of the Tibetan Plateau by using the MODIS and in-situ data
Authors: Ma Y. , Zhong L. , Wang B. , Ma W. , Chen X. , Li M.
Published: July 2011

Abstract. In this study, a parameterization methodology based on MODIS (Moderate Resolution Imaging Spectroradiometer) and in-situ data is proposed and tested for deriving the regional surface reflectance, surface temperature, net radiation flux, soil heat flux, sensible heat flux and latent heat flux over heterogeneous landscape. As a case study, the methodology was applied to the Tibetan Plateau area. Four images of MODIS data (30 January 2007, 15 April 2007, 1 August 2007 and 25 October 2007) were used in this study for the comparison among winter, spring, summer and autumn. The derived results were also validated by using the "ground truth" measured in the stations of the Tibetan Observation and Research Platform (TORP). The results show that the derived surface variables (surface reflectance and surface temperature) and surface heat fluxes (net radiation flux, soil heat flux, sensible heat flux and latent heat flux) in four different seasons over the Tibetan Plateau area are in good accordance with the land surface status. These parameters show a wide range due to the strong contrast of surface features over the Tibetan Plateau. Also, the estimated land surface variables and surface heat fluxes are in good agreement with the ground measurements, and all their absolute percent difference (APD) is less than 10 % in the validation sites. It is therefore concluded that the proposed methodology is successful for the retrieval of land surface variables and surface heat fluxes using the MODIS and in-situ data over the Tibetan Plateau area. The shortage and further improvement of the methodology were also discussed.
Atmospheric CO2 monitoring with single-cell NDIR-based analyzers
Authors: Stephens B. B. , Miles N. L. , Richardson S. J. , Watt A. S. , Davis K. J.
Published: July 2011

Abstract. We describe CO2 concentration measurement systems based on relatively inexpensive single-cell non-dispersive infrared CO2 sensors. The systems utilize signal averaging to obtain precision (1-σ in 100 s) of 0.1 parts per million dry air mole fraction (ppm), frequent calibrations and sample drying in order to achieve state-of-the-art compatibility, and can run autonomously for months at a time. Laboratory tests indicate compatibility among four to six systems to be ±0.1 ppm (1-σ), and field measurements of known reference-gases yield median errors of 0.01 to 0.17 ppm with 1-σ variance of ±0.1 to 0.2 ppm. From May to August 2007, a system co-located with a NOAA-ESRL dual-cell NDIR system at the WLEF tall tower in Wisconsin measured daytime-only daily averages of CO2 that differ by 0.26 ± 0.15 ppm (median ± 1 σ), and from August 2005 to April 2011 a system co-located with weekly NOAA-ESRL network flask collection at Niwot Ridge, Colorado measured coincident CO2 concentrations that differed by −0.06 ± 0.30 ppm (n = 585). Data from these systems are now supporting a wide range of analyses and this approach may be applicable in future studies where accuracy and initial cost of the sensors are priorities.
Stable carbon isotopes as indicators for environmental change in palsa peats
Authors: Alewell C. , Giesler R. , Klaminder J. , Leifeld J. , Rollog M.
Published: July 2011

Abstract. Palsa peats are unique northern ecosystems formed under an arctic climate and characterized by a high biodiversity and sensitive ecology. The stability of the palsas are seriously threatened by climate warming which will change the permafrost dynamic and induce a degradation of the mires. We used stable carbon isotope depth profiles in two palsa mires of Northern Sweden to track environmental change during the formation of the mires. Soils dominated by aerobic degradation can be expected to have a clear increase of carbon isotopes (δ13C) with depth, due to preferential release of 12C during aerobic mineralization. In soils with suppressed degradation due to anoxic conditions, stable carbon isotope depth profiles are either more or less uniform indicating no or very low degradation or depth profiles turn to lighter values due to an enrichment of recalcitrant organic substances during anaerobic mineralisation which are depleted in 13C. The isotope depth profile of the peat in the water saturated depressions (hollows) at the yet undisturbed mire Storflaket indicated very low to no degradation but increased rates of anaerobic degradation at the Stordalen site. The latter might be induced by degradation of the permafrost cores in the uplifted areas (hummocks) and subsequent breaking and submerging of the hummock peat into the hollows due to climate warming. Carbon isotope depth profiles of hummocks indicated a turn from aerobic mineralisation to anaerobic degradation at a peat depth between 4 and 25 cm. The age of these turning points was 14C dated between 150 and 670 yr and could thus not be caused by anthropogenically induced climate change. We found the uplifting of the hummocks due to permafrost heave the most likely explanation for our findings. We thus concluded that differences in carbon isotope profiles of the hollows might point to the disturbance of the mires due to climate warming or due to differences in hydrology. The characteristic profiles of the hummocks are indicators for micro-geomorphic change during permafrost up heaving.
Can Mg isotopes be used to trace cyanobacteria-mediated magnesium carbonate precipitation in alkaline lakes?
Authors: Shirokova L. S. , Mavromatis V. , Bundeleva I. , Pokrovsky O. S. , Bénézeth P. , Pearce C. , Gérard E. , Balor S. , Oelkers E. H.
Published: July 2011

Abstract. The fractionation of Mg isotopes was determined during the cyanobacterial mediated precipitation of hydrous magnesium carbonate precipitation in both natural environments and in the laboratory. Natural samples were obtained from Lake Salda (SE Turkey), one of the few modern environments on the Earth's surface where hydrous Mg-carbonates are the dominant precipitating minerals. This precipitation was associated with cyanobacterial stromatolites which were abundant in this aquatic ecosystem. Mg isotope analyses were performed on samples of incoming streams, groundwaters, lake waters, stromatolites, and hydromagnesite-rich sediments. Laboratory Mg carbonate precipitation experiments were conducted in the presence of purified Synechococcus sp cyanobacteria that were isolated from the lake water and stromatolites. The hydrous magnesium carbonates nesquehonite (MgCO3·3H2O) and dypingite (Mg5(CO3)4(OH)25(H2O)) were precipitated in these batch reactor experiments from aqueous solutions containing either synthetic NaHCO3/MgCl2 mixtures or natural Lake Salda water, in the presence and absence of live photosynthesizing Synechococcus sp. Bulk precipitation rates were not to affected by the presence of bacteria when air was bubbled through the system. In the stirred non-bubbled reactors, conditions similar to natural settings, bacterial photosynthesis provoked nesquehonite precipitation, whilst no precipitation occurred in bacteria-free systems in the absence of air bubbling, despite the fluids achieving a similar or higher degree of supersaturation. The extent of Mg isotope fractionation (Δ26Mgsolid-solution) between the mineral and solution in the abiotic experiments was found to be identical, within uncertainty, to that measured in cyanobacteria-bearing experiments, and ranges from −1.4 to −0.7 ‰. This similarity refutes the use of Mg isotopes to validate microbial mediated precipitation of hydrous Mg carbonates.
Soil moisture control over autumn season methane flux, Arctic Coastal Plain of Alaska
Authors: Sturtevant C. S. , Oechel W. C. , Zona D. , Emerson C. E.
Published: July 2011

Abstract. Two shortfalls in estimating current and future seasonal budgets of methane efflux in Arctic regions are the paucity of non-summer measurements and an incomplete understanding of the sensitivity of methane emissions to changes in tundra moisture. A recent study in one Arctic region highlighted the former by observing a previously unknown large methane pulse during the onset of autumn soil freeze. This study addresses these research gaps by presenting an analysis of eddy covariance measurements of methane efflux and supporting environmental variables during the autumn season of 2009 and associated soil freeze-in period at our large-scale water manipulation site near Barrow, Alaska (the Biocomplexity Experiment). We found that methane emissions during the autumn were closely tied to liquid soil moisture in the top 30 cm of soil. Declines in soil moisture between manipulated wet, intermediate, and dry conditions as well as through time during the soil freeze-in period led to corresponding declines in methane efflux. During the period of soil freeze-in (from 23 September to 28 October), we estimate that our wet section emitted 623 mg CH4 m−2 while the dry section emitted only 253 mg CH4 m−2, the average of which represents 18 % of net emissions from the typically measured growing season. We did not find evidence for a pulse in methane emissions during soil freeze at this site. Results from this study imply that future changes in tundra moisture will have a large effect on methane emissions in this region, and changes which span the saturation point are likely to have the largest effect. We speculate that changes in autumn soil moisture are also likely to affect winter emissions via the insulative effects of ice on winter soil temperature and liquid soil moisture availability after bulk soil freeze. Further research should expand the use of eddy covariance methane flux measurements to investigate ecosystem-level effects of tundra moisture on autumn and winter methane emissions in this and other Arctic regions.
The significance of nitrous oxide emission from biofuel crops on arable land: a Swedish perspective
Authors: Kasimir Klemedtsson Å. , Smith K. A.
Published: July 2011

Abstract. The current regulations governing biofuel production in the European Union require that they have to mitigate climate change, by producing >35 % less greenhouse gases (GHG) than fossil fuels. There is a risk that this may not be achievable, since land use for crop production inevitably emits the strong GHG nitrous oxide (N2O), due to nitrogen fertilisation and cycling in the environment. We conclude that efficient agricultural crop production resulting in a good harvest and low N2O emission can fulfill the EU standard, and is possible under certain conditions for the Swedish agricultural and refinery production systems. However, in years having low crop yields total GHG emissions can be even higher than those released by burning of fossil fuels. In general, the N2O emission size in Sweden and northern Europe is such that there is a >50 % chance that the 35 % saving requirement will not be met. Thus ecosystem N2O emissions have to be convincingly assessed. Here we compare Swedish emission data with values estimated by means of statistical models and by a global, top-down, procedure; the measurements and the predictions often show higher values that would fail to meet the EU standard and thus prevent biofuel production development.
Hydraulic analysis of river training cross-vanes as part of post-restoration monitoring
Authors: Endreny T. A. , Soulman M. M.
Published: July 2011

Abstract. River restoration design methods are incrementally improved by studying and learning from monitoring data in previous projects. In this paper we report post-restoration monitoring data and simulation analysis for a Natural Channel Design (NCD) restoration project along 1600 m of the Batavia Kill (14 km2 watershed) in the Catskill Mountains, NY. The restoration project was completed in 2002 with goals to reduce bank erosion and determine the efficacy of NCD approaches for restoring headwater streams in the Catskill Mountains, NY. The NCD approach used a reference-reach to determine channel form, empirical relations between the project site and reference site bankfull dimensions to size channel geometry, and hydraulic and sediment computations based on a bankfull (1.3 yr return interval) discharge to test channel capacity and sediment stability. The NCD project included 12 cross-vanes and 48 j-hook vanes as river training structures along 19 meander bends to protect against bank erosion and maintain scour pools for fish habitat. Monitoring data collected from 2002 to 2004 were used to identify aggradation of pools in meander bends and below some structures. Aggradation in pools was attributed to the meandering riffle-pool channel trending toward step-pool morphology and cross-vane arms not concentrating flow in the center of the channel. The aggradation subsequently caused flow splitting and 4 partial point bar avulsions during a spring 2005 flood with a 25-yr return interval. Processing the pre-flood monitoring data with hydraulic analysis software provided clues the reach was unstable and preventative maintenance was needed. River restoration and monitoring teams should be trained in robust hydraulic analytical methods that help them extend project restoration goals and structure stability.
Dynamic magma mixing revealed by the 2010 Eyjafjallajökull eruption
Authors: Sigmarsson O. , Vlastelic I. , Andreasen R. , Bindeman I. , Devidal J.-L. , Moune S. , Keiding J. K. , Larsen G. , Höskuldsson A. , Thordarson Th.
Published: July 2011

Abstract. Injection of basaltic magmas into silicic crustal holding chambers and subsequent mixing of the two components is a process that has been recognised since the late seventies to have resulted in explosive eruptions. Detailed reconstruction and assessment of the mixing process caused by such intrusion is now possible because of the exceptional time-sequence sample suite available from the tephra fallout of the 2010 summit eruption at Eyjafjallajökull volcano in South Iceland. From 14 to 19 April the tephra contains three glass types of basaltic, intermediate, and silicic compositions recording rapid magma mingling without homogenisation, involving evolved FeTi-basalt and dacite with composition identical to that produced by the 1821–1823 AD Eyjafjallajökull summit eruption. The time-dependent change in the magma composition suggests a binary mixing process with changing end-member compositions and proportions, or dynamic magma mixing. Beginning of May, a new injection of deep-derived basalt was recorded by deep seismicity, appearance of magnesium-rich olivine phenocrysts together with high sulphur output and presence of sulphide crystals. Thus the composition of the basaltic injection became more primitive and hotter with time prowoking changes in the silicic mixing end-member from pre-existing melt to the solid carapace of the magma chamber. Decreasing proportions of the mafic end-member with time in the erupted mixed-magma, demonstrate that injections of Mg-rich basalt was the motor of the 2010 Eyjafjallajökull explosive eruption, and that its decreasing inflow terminated the eruption. Significant quantity of silicic magma is thus still present in the interior of the volcano. Our results show that detailed sampling during the entire eruption was essential for deciphering the complex magmatic processes at play, namely the dynamic magma mixing. Finally, the rapid compositional changes in the eruptive products suggest that magma mingling occurs on a timescale of few hours to days whereas the interval between the first detected magma injection and eruption was several months.
EVALUATION OF INHOMOGENEITIES IN HISTOLOGICAL STRUCTURES (CARTILAGE, RETINA)
Authors: Muche Lutz , Rother Paul , Friesenegger Antje , Geupel Markus
Published: July 2011

This paper investigates histological tissues by means of image analysis and spatial statistics. For the quantification of cell frequencies and accumulations two statistical characteristics, intensity function and cluster density, are suggested. The samples are histological sections of human articular cartilage and human retina considered in view of changes during the ageing process. The articular cartilage is characterized by continuous changes of both functions, the cell intensity as well as the clusterization. In contrast, the retina is a trilaminar structure formed in the early embryonic stage without changes by ageing.
MEASUREMENT OF ROOT LENGTH DENSITY IN INTACT SAMPLES USING X-RADIOGRAPHY AND IMAGE ANALYSIS
Authors: Pierret Alain , Moran Chris J , Mclachlan Colin B , Kirby John M
Published: July 2011

Measurement of root system attributes is of critical importance to understand and model plant growth. Root length density, the length of roots per unit volume of soil, is one of the important parameters required to understand plant performance. Measuring techniques currently in use to assess this parameter, such as for example core washing, are notoriously imprecise and labour-intensive. Roots and soil being inextricably linked, it is virtually impossible to separate them without loosing a significant amount of the root sample to be measured. This noticeably compromises the accuracy of washing techniques. For this reason, non-invasive measurement approaches are highly desirable. Here, a method based on the combination of X-radiography and image analysis is proposed as a new alternative for the measurement of root length density from intact samples. The successive steps of the method, from sampling to image acquisition are briefly described. A specific measurement algorithm, designed to account for the complex spatial arrangement of the roots within the samples is then presented and discussed in detail.
DEEP FOCUS; A DIGITAL IMAGE PROCESSING TECHNIQUE TO PRODUCE IMPROVED FOCAL DEPTH IN LIGHT MICROSCOPY
Authors: Goldsmith Noel T
Published: July 2011

In light microscopy, the spatial transverse resolution is a function of the wavelength and numerical aperture. The depth resolution is another function of these parameters. The factors that enable the detection of fine detail, make the sharp focusing of more than a thin slice of the depth in an object impossible. When the examination of fracture surfaces is attempted using light reflection microscopy, the roughness will often restrict the in-focus parts of an image to a small portion of the field of view. Several authors have presented methods that enable a set of digitised images to be processed into a single composite image which contains the in-focus parts from each image. These methods are effective, unfortunately the noise present in each digital image is accumulated, resulting in increasingly noisy composite images as the number of images in a set is increased. During processing, a separate image depicting the heights in the surface, i.e. a contour map, may be produced. This image is the key that enables the production of an in focus composite image which does not accumulate noise. Image analysis under computer control will frequently require the use of automatic focusing. Several authors have published criteria which may be used to determine the state of focus of an image. Such criteria have a clear application to the above process. This paper presents an evaluation of some methods used for the processing of such images, and also some procedures used for the determination of sharpness of focus and demonstrates a sensitive method for the evaluation of such procedures. Finally, an implementation of a method which uses the one of the simplest focus criteria is presented, and a procedure for the production of deep focus images which are free from the accumulation of noise.
AN ATTEMPT AT AN ALGEBRAIC THEORY OF CRYSTAL STRUCTURE. PART 4.
Authors: Aboav David A
Published: July 2011

Since, for reasons to be examined in a later instalment of this work, the postulates of Euclid do not seem suited for the purpose, an attempt is made to classify regularities in the observed diffraction of X-rays by matter in the crystalline state on a 'Pythagorean', or purely numerical basis. "I am quite satisfied if we have the machinery for making predictions, even if we are unable to understand it clearly" (Einstein, 1953).
STEREOLOGICAL CORRECTION OF MINERAL LIBERATION GRADE DISTRIBUTIONS ESTIMATED BY SINGLE SECTIONING OF PARTICLES
Authors: Spencer Steven , Sutherland David
Published: July 2011

The liberation distribution of ore samples is of considerable interest for process optimisation in the minerals industry. A scanning electron microscope-based automatic mineral analyser such as the LEO QEMSCAN system developed by CSIRO Minerals is a powerful tool for the estimation of linear or areal grade distributions of a population of ore particles based upon polished single particle sections. Stereological correction of a single section mineralogical grade distribution is recognised as an ill-posed inverse problem. The transformation kernel method with constrained entropy regularisation (King and Schneider, 1998) is adopted for the correction of stereological error in binary systems. An enhanced transformation kernel correction scheme is developed with an additional equality constraint for average grade as determined by section and volumetric sampling, in accordance with Delesse's fundamental stereological theorem. The usefulness of both correction methods is limited by the availability of kernels that appropriately model the relationship between volumetric and section grade distributions for the mineralogical sample of interest. The transformation kernel stereological correction methods are implemented in software available for use as part of the LEO QEMSCAN system. Both correction procedures are applied to areal section grade distributions of feed and concentrate from a mineral processing plant. The corrected grade distributions are in some instances found to be sensitive to the application of the average grade constraint. The statistical significance of differences in the corrected solutions is discussed.
SPATIO-TEMPORAL DATA ANALYSIS WITH NON-LINEAR FILTERS: BRAIN MAPPING WITH fMRI DATA
Authors: Rodenacker Karsten , Hahn Klaus , Winkler Gerhard , Auer Dorothea P
Published: July 2011

Spatio-temporal digital data from fMRI (functional Magnetic Resonance Imaging) are used to analyse and to model brain activation. To map brain functions, a well-defined sensory activation is offered to a test person and the hemodynamic response to neuronal activity is studied. This so-called BOLD effect in fMRI is typically small and characterised by a very low signal to noise ratio. Hence the activation is repeated and the three dimensional signal (multi-slice 2D) is gathered during relatively long time ranges (3-5 min). From the noisy and distorted spatio-temporal signal the expected response has to be filtered out. Presented methods of spatio-temporal signal processing base on non-linear concepts of data reconstruction and filters of mathematical morphology (e.g. alternating sequential morphological filters). Filters applied are compared by classifications of activations.
RELATIVE DISTANCE: THE KEY TO THE SHAPE OF HEPATIC BUILDING BLOCKS
Authors: Ruijter Jan M , Markman Marry M , Hagoort Jaco , Moorman Antoon FM , Lamers Wouter H
Published: July 2011

The delineation and the shape of the smallest structural units of the liver is still the subject of debate. However,the blood flow from an upstream terminal branch of the portal vein to a downstream central vein is thought to induce a functional zonation in hepatocyte gene expression. This property was used to determine boundary conditions for the shape of the hepatic building blocks. Histochemical techniques that specifically label periportally or pericentrally expressed enzymes can be used to distinguish periportal and pericentral areas in a liver section. Pairs of images from aligned serial sections, one stained for a portal and the next for a central enzyme, are used. Segmentation and skeletonisation of these images results in the skeletons of the portal and central areas. Distance transformation with respect to these skeletons gives for each point in the image pair the distance to the nearest terminal branches of the portal vein and the central vein. For each point the relative position on the porto-central radius can then be calculated as its distance to a portal vein divided by the sum of its portal and its central distance. In the resulting relative radius image, the area occupied by 'zones' of equivalent relative radius can be measured. According to the principle of Delesse the relative area of a zone in the image is equal to the relative volume of that zone in the tissue. For structural units of plate-like, cylindrical or spherical shape, the relative volume of a zone is equal to the relative radius of that zone to the power 1, 2 or 3, respectively. Thus, the exponent in the relative area - relative radius relation gives information on the shape of the structural unit. Measurement of the areas of each relative radius zone and determination of the area - radius relation in images of random sections of adult mouse liver results in an exponent of 1.1. This suggests that the smallest structural unit of the mouse liver has the shape of a needle.
STEREOLOGICAL ESTIMATION OF TUBULAR LENGTH FROM THIN VERTICAL SECTIONS
Authors: Clausen Helle V , Gundersen Hans Jørgen G , Larsen Lise G
Published: July 2011

In this study tubular structures are represented by stem villous arteries of the human placenta. The architecture of the vascular tree in the human placenta makes it appropriate to use vertical histological sections. Describing tubules, estimates of total length and diameter are informative. The aim of the study was to derive a new stereological estimator of the total length of circular tubules observed in thin vertical sections. Design: Dual perfusion fixed human placentas. Systematic, uniformly random sampling of vertical sections. Five-μm-sections were stained by haematoxylin and eosin (H&E) and the vertical axis was identified in all sections. A test system with cycloid test lines was used. Since tubular surface area is proportional to length and diameter, S ∝ πdL, surface-weightening is equivalent to diameter×lengthweightening. As each diameter (extra weight) is known, one may eliminate the diameter-weightening by computing the harmonic mean diameter, which is thus the correct, length-weighted mean tubular diameter, dL = d hS . Surface area is estimated in the ordinary way from vertical sections, and with unbiased and robust estimates of S and dL respectively, total length may be estimated L = S / πdhs Conclusion: A new stereological estimator of total length of a circular tubular structure observed in thin vertical sections is presented.
ESTIMATING NUMBER DENSITY NV – A COMPARISON OF AN IMPROVED SALTYKOV ESTIMATOR AND THE DISECTOR METHOD
Authors: Davtian Ashot , Hahn Ute , Ohser Joachim , Stoyan Dietrich
Published: July 2011

Two methods for the estimation of number per unit volume NV of spherical particles are discussed: the (physical) disector (Sterio, 1984) and Saltykov's estimator (Saltykov, 1950; Fullman, 1953). A modification of Saltykov's estimator is proposed which reduces the variance. Formulae for bias and variance are given for both disector and improved Saltykov estimator for the case of randomly positioned particles. They enable the comparison of the two estimators with respect to their precision in terms of mean squared error.
STEREOLOGICAL QUANTITATION OF LEYDIG AND SERTOLI CELLS IN THE TESTIS FROM YOUNG AND OLD MEN
Authors: Petersen Peter M , Pakkenberg Bente
Published: July 2011

One of the newer stereological methods, the optical fractionator, was applied to the study of the effects of ageing on the human testis. The estimated total number of Sertoli and Leydig cells per testis in men younger than 30 years were 430×106 (CV = SD/mean = 0.35) and 117×106 (CV = 0.53), respectively, while in men older than 50 years the estimated total Sertoli cell number was 266×106 (CV = 0.46) and the mean Leydig cell number 83×106 (CV = 0.53). The difference between the number of Sertoli cells in men younger than 30 years compared with men older than 50 years was close to statistical significance (p = 0.052) while no differences was found in total Leydig cell number (p = 0.22).
TOTAL CELL NUMBER IN FETAL BRAIN
Authors: Samuelsen Grethe Badsberg , Bogdanović Nenad , Laursen Henning , Graem Niels , Larsen Jørgen Falck , Pakkenberg Bente
Published: July 2011

In this study the material comprises brains from three aborted fetuses and two fullterm infants who died at birth.The gestational ages ranged from the 22nd week to term. All cases were without malformations, known chromosomal abnormality, hydrops, and systemic infections, and all had normal birth weights with fetal growth indices (observed birth weight/expected mean birth weight) between 0.9 - 1.05. The preliminary results show a five fold increase in the total cell population in the marginal zone/cortical plate, MZ/CP (future neocortex), from week 22 until term. In the transient subplate zone, SP, the total cell number was more than doubled from week 22 to week 30-35, and then decreased towards term. In the intermediate zone, IZ (future white matter), the total cell population was doubled from week 22 until term. The total cell number in the entricular/subventricular zone, VZ/SZ (germinal matrix), was reduced by a factor of five from week 22 until term. A histological differentiation between neurons and glial cells was not possible. The optical fractionator was used to estimate the total cell population in four characteristic developmental zones in the human fetal brain. Fetal brain tissue undergoes considerable and rather unpredictable shrinkage during fixation. However, using the fractionator principle it is possible to eliminate this problem, provided that the structure of interest (one brain hemisphere) is fully intact.
HOW MANY LOBSTERS ARE IN THE SEA?
Authors: Enns Ernest , Smith Bruce
Published: July 2011

A lobster fishery must have a reasonable estimate of the number of lobsters within the fishery in order to regulate the annual harvest. Stereological sampling procedures are used to estimate the number of lobsters in a defined region of the sea. From a given point in the fishery, a selective sample in a random direction to the boundary of the fishery is taken. This is repeated to generate a systematic sample from which the total population is estimated.
IMAGE ANALYSIS FOR MODELLING SHEAR BEHAVIOUR
Authors: Lopez Philippe , Riss Joëlle , Gentier Sylvie , Flamand Rock , Archambault Guy , Bouvet Soizic
Published: July 2011

Through laboratory research performed over the past ten years, many of the critical links between fracture characteristics and hydromechanical and mechanical behaviour have been made for individual fractures. One of the remaining challenges at the laboratory scale is to directly link fracture morphology of shear behaviour with changes in stress and shear direction. A series of laboratory experiments were performed on cement mortar replicas of a granite sample with a natural fracture perpendicular to the axis of the core. Results show that there is a strong relationship between the fracture's geometry and its mechanical behaviour under shear stress and the resulting damage. Image analysis, geostatistical, stereological and directional data techniques are applied in combination to experimental data. The results highlight the role of geometric characteristics of the fracture surfaces (surface roughness, size, shape, locations and orientations of asperities to be damaged) in shear behaviour. A notable improvement in shear understanding is that shear behaviour is controlled by the apparent dip in the shear direction of elementary facets forming the fracture.