Small Sample Areas Research Articles

Medieval Painted Decoration in St Michael’s Church in Mihkli, Estonia

Anneli Randla: Medieval painted decoration in St Michael’sin Mihkli, EstoniaKeywords: medieval murals, church decoration, paint research, technical studies of artSummary:Recent studies in the medieval St Michael’s Church in Mihkli, in western Estonia, have shown that the stone church was constructed in two stages: at first a simple building with wooden ceiling was erected, and at a later date (possibly around 1500) stone vaulting was added over the first chancel and the nave. In August 2013, preliminary investigations were undertaken to study the painted decoration of the inner walls and vaults of the church. The small sample areas uncovered were sufficient to reveal several historical colour schemes. The richest decorationis contemporary with the first plastering of the vaults since the plaster was still moist when the paint was applied. The decoration is vernacular in character and its aim is to enhance the architectural features of the building. Thus the ribs and corbels of the vaults are painted but the decoration is extended to flat surfaces as well. For example painted pendants in grey and red adorn the ends of the ribs of the eight-partite vault of the chancel. The largest composition was discovered in the eastern bay of the nave around the vault boss. An irregular eight-petalled red flower is formed around the boss with a cross on it. These paintings might have been executed by local church builders rather than by professional craftsmen.CV :Anneli Randla earned her PhD in art history at the University ofCambridge in 1999. She has worked for the National Heritage Board of Estonia for ten years. Since 2008 Randla has been an associate professor in the Department of Conservation at the Estonian Academy of Arts and currently she serves as the dean of the Faculty of Art and Culture at the academy. Her main research interests are: medieval ecclesiastical architecture, medieval murals, technical studies of art and the history of conservation.

XRD<sup>2</sup> Stress Measurement for Samples with Texture and Large Grains

Stress measurement on samples with texture and large grains is always a challenge. The diffraction peak intensity varies dramatically with different sample orientation. The macroscopic elasticity becomes anisotropic due to strong preferred orientation. The large grains may results in a big error in 2θ due to poor sampling statistics. The fitting results of the conventional sin2ψ method is extremely sensitive to texture and large grains. When stress is measured with a 2D detector, most of the above adverse effects can be minimized or eliminated. The data integration helps to smooth out rough diffraction profiles due to large grain size, texture, small sample area or weak diffraction. The large angular coverage and multiple diffraction rings can minimize the effect of the macroscopic anisotropy. The weighted least squares regression and intensity threshold can further reduce the effect of poor statistics associated with texture and large grains. Multiple {hkl} rings may be used to measure the stress to improve the statistics and minimize the elastic anisotropy effect.

Workshop on membrane fouling and monitoring: a summary

Gathering for a workshop hosted by Robert Field at Oxford University, some of the world’s leading experts in membrane fouling presented and discussed recent research progress in this area. The delegates paid particular attention to the key issue of biofouling because of its importance in water treatment and its inherent complexity compared to the mechanics of inorganic particulate fouling. It was remarked that the characterisation and understanding of the extracellular polymeric substances (EPS) in biofilms, and the transparent exopolymers (TEP) involved in their development is still a particularly difficult task, which was a subject present during the entire workshop. Furthermore, advances in characterisation of fouling layers and biofilms utilising ultrasonic time-domain reflectometry (UTDR) and confocal laser scanning microscopy (CLSM) were presented, along with a cautionary perspective on interpretation of data from small sample areas. While membrane fouling reduction is traditionally tackled with a prevention and removal strategy, an alternative “biofilm management” approach was put forward. Although a lot of physical and chemical techniques were presented, delegates also stressed the importance of microbiology for getting the whole picture and the need for a range of carefully selected analytical techniques to do so. This paper summarises the proceedings and discussion at this workshop in September 2012.

Scaling pairwise β-diversity and α-diversity with area

Aim The relationship between species richness (α-diversity) and area is well studied; however, the way in which compositional dissimilarity between pairs of sites (β-diversity) scales with area has only recently attracted research attention. The aim of this study was to improve the understanding of how both α- and β-diversity scale with area, to illuminate ecological processes structuring the distribution of biodiversity and enable prediction of α- and β-diversity for large regions from much smaller samples. Location We examined both simulated spatial community data and measurements from tropical forest tree plots in Panama. Methods We applied the simulated and measured community data to assess how both α- and β-diversity scale with area. Then we examined how accurately community α-diversity and pairwise β-diversity can be extrapolated from small sample areas of different size within each community, using the species–area power relationship. Results For both the simulated and tree plot data, pairwise β-diversity scaled with area in a corresponding manner to the much more familiar species–area relationship. By altering the attributes of the simulated communities, we found that α- and β-diversity saturated at smaller areas where abundances were more even, species distributions were less aggregated and regional richness was lower. Estimates of α- and β-diversity for a pair of communities generally increased in accuracy with the size of the local sample areas from which extrapolations were made. Main conclusions These analyses suggest that the most robust estimates of α- and β-diversity for a larger area will be obtained by local samples that are greater than 10% the size of that larger area. Our results emphasize the fundamental link in how both α- and β-diversity scale with area, and demonstrate how simple knowledge of these scaling relationships can be used to predict the diversity of larger areas from smaller samples.

New approach to evaluate area-dependent breakdown characteristics of dielectric polymer films

A new dielectric breakdown measurement method for determining breakdown characteristics of polymer films has been developed and evaluated. The method is based on measurement of multiple breakdowns per sample area beyond the weakest point of the film by utilizing low-energy self-healing breakdown of metallized polymer film. A data selection process based on the discharge energy characteristics of each measured self-healing breakdown is utilized prior to the statistical analysis in order to validate the mutual independence of the results. Even with a relatively small sample area, the method yields a large amount of breakdown data from a wide voltage spectrum, thus enabling the formation of detailed material-specific breakdown fingerprints. The measurement system and the area dependence of the breakdown results have been evaluated with capacitor-grade metallized film. For the statistical analysis, additively mixed Weibull distributions are utilized as multiple breakdown mechanisms are found to be operative in the dielectric. Defects in the dielectric volume are found to have a profound effect on the structure of the mixed distribution with increasing area.

Sample preparation and image acquisition using optical‐reflective microscopy in the measurement of fiber orientation in thermoplastic composites

A complete sample preparation procedure used to determine three-dimensional fiber orientation from optical micrographs of glass fiber-reinforced thermoplastic composites is presented. Considerations for elimination of irregularities in the elliptical footprints, contrast enhancement between fibers and surrounding polymer matrix, controlled-etching that allows the identification of small shadows where fiber recedes into the matrix, and topographical reconstruction of the elliptical footprint are described in the procedure. This procedure has produced high-quality optical micrographs employed to obtain accurate fiber orientation data for thermoplastic composites using the method of ellipses. The optimal definition of the nonelliptical footprints' borders allows an accurate measurement of orientation in small sampling areas.

Sampling Area Selection for the Assessment of Goblet Cell Density From Conjunctival Impression Cytology Specimens

To assess the impact of using different sampling areas (fields of view) on the reliability of goblet cell density (GCD) estimates from conjunctival impression cytology (CIC) specimens from healthy individuals. The CIC specimens were collected from the exposed nasal bulbar conjunctiva of 5 adult subjects (average age, 23 years) onto Biopore (Millicell) membranes and stained with Giemsa. A region from each of the specimens that contained abundant goblet cells was examined by light microscopy using a ×40 magnification objective lens, ×20 and ×10 lenses, the images were enlarged, and the goblet cells were marked and counted. The GCD values per square millimeter were calculated and then the impact of counting between 10 to many and 10 to few goblet cells assessed. The mean GCD estimates at ×400 magnification, ×200, and ×100 were 950 ± 226, 620 ± 154 and 471 ± 158 cells per square millimeter, respectively; these values were statistically different (P<0.05). The GCD estimates could change by as much as ±31.6%, ±12.2%, and ±4.2% for differences of ±10 cells counted per image. As a result of variability in goblet cell distribution across CIC specimens, the estimates of GCD can be expected to be different according to the sampling area used for goblet cell counts. Furthermore, the use of a small sampling area (high power field of view) is likely to result in an unacceptably large uncertainty (variability) in the GCD estimates.

Diversity and community composition of ectomycorrhizal fungi in a dry deciduous dipterocarp forest in Thailand

Large forest areas of South-East Asia, are dominated by the Dipterocarpaceae tree family, which contains many important timber species. Unlike many other tropical trees, Dipterocarpaceae rely on ectomycorrhizal (ECM) root symbiosis for their mineral nutrition. This study aims to document the richness and community composition of ECM fungi in a dry deciduous forest in Thailand. Combining morphological and molecular identification methods revealed 69 species of ECM fungi that belong to 17 phylogenetic lineages. The /russula-lactarius, /tomentella-thelephora, /sordariales, /sebacina and /cantharellus lineages were the most species-rich. The fungal richness is comparable to other tropical rain forest sites, but the phylogenetic community structure has elements of both tropical and temperate ecosystems. Unlike tropical rain forests, the Cenococcum geophilum complex was one of the most frequent fungal taxa that had a relatively high ITS genetic diversity over the small sampling area. This study provides the first snapshot insight into the fungal community of dry dipterocarp forests. However, it is necessary to broaden the spatial and temporal scales of sampling to improve our understanding of the below-ground relations of dry and humid tropical forests.

Sampling precision and variability of tree species abundance ranks in a semideciduous Atlantic forest fragment

Among other objectives, forest inventories are aimed to identify ecological communities and to correlate community composition with environmental variables. The identification of different communities would require several forest inventories, each covering small sampling areas with relatively homogeneous environmental conditions. The multiple plot sampling method, traditionally used in local inventories of tropical forests, cannot assure such homogeneity, since even small sampling areas would show environmental heterogeneity influencing vegetation. In this paper we assessed the consequences of this heterogeneity for sampling by quantifying the variability of species abundance ranks for species sampled with 10 or more individuals in a set of plots covering a small sampling area. The species reference abundance ranks were obtained from a sample of 100 plots of 10 m × 10 m each randomly set in a sampling area of 6.5 ha in a tropical forest fragment (Southeastern Brazil). For each species we used resamplings (30 trials) to obtain the species abundance ranks in sub-samples, considering different sampling intensities (n = 25, 50 and 75 plots), and compared these ranks with the species reference rank (n = 100 plots). Then, we compared the species ranks in sub-samples of 50 plots (10.000 trials) with the reference rank and assessed the frequency and extent of rank displacements. Species rank was highly variable across resampling trials for the sampling intensities of n = 25 and n = 50, but decreased considerable with a sampling intensity of n = 75 plots. The mean rank variability and especially the maximum displacement raised significantly from the seventh most abundant species on, and some species occupied quite discrepant abundance ranks in up to 10% of the 10.000 resampling trials. This high internal variability of forest samples may impair the search for floristic patterns as scale lessens, say, to the meso-scale (1–100 km2). We discussed some possible ways to increase internal homogeneity of tropical forest samples with the multiple plot sampling method. Among these, objective entitation, based on an ancient phytosociological procedure, is suggested as the most appropriate for use on the hilly relieves of the Atlantic forest biome.

Sampling bivalves on tidal flats: possibility of ­missing rare species, versus smoothing of ­environmental variation

Beukema & Dekker (2011; Mar Ecol Prog Ser 440:281�283) argue that the main con- clusion of Compton et al. (2008; Mar Ecol Prog Ser 373:25-35), namely that diversity of bivalve and other benthic organisms on tidal flats is not associated with sediment heterogeneity, is invalid because γ-diversity was not examined. Our conclusion was, however, based on γ-diversity. Beu kema & Dekker (2011) also argue that our finding that bivalve point diversity was highest in 'complex' fine-grained sediments is incorrect, because small sampling areas underestimate rare species. Using larger sampling areas would have increased the probability of including rare species, but would also have smoothed away biological and environmental heterogeneity. We used many estimates of point diversity to show that bivalve diversity at a sampling point was higher in finer versus sandier sediments across 9 mudflats and we did not make assumptions about the homogeneity of habitat types. The suggestion that samples should be aggregated on the basis of similar environmental attributes across an area as large as the Wadden Sea would also lead to an under- or overestimation of species diversity because — although sampling locations may share the same sediment characteristics — species composition within a sample will differ due to historical, physical and biological effects.

The Status of Floristic Analysis of Mt. Pangasugan, Leyte, Philippines – a Conservation Priority Area Classified as “Extremely High Critical”

the island of Leyte in the Eastern Visayas takes a central position between the Philippine main islands of Luzon and Mindanao. It is characterized by the Leyte cordillera, which is part of the Philippine fault line. Within the Leyte cordillera, Mt. Pangasugan takes an exceptional role since it provides a catena from lowland forest remnants on its foothills to mossy forest on its summit at 1158 m a.s.l.. recently, Mt. Pangasugan has been identified as conservation priority area classified as of ‘extremely high critical’ level. Mt. Pangasugan has been the focus of comprehensive botanical studies within the last few years. We present the current status of the floristic assessment of the mountain and introduce the Visayas state University Herbarium, located at the foot of Mt. Pangasugan, where the majority of collected specimens are deposited. At present, the Herbarium houses c. 6100 specimens, 3000 of them originating from the primary forest of Mt. Pangasugan. based on the present status of specimen processing and identification they represent 115 families, and 418 genera of Angiosperms, 2 families, 2 genera, and 3 species of Gymnosperms, 27 families and 64 genera of Pteridophytes, and 3 classes, 38 genera and 51 species of bryophytes. the number of vascular plant species represented in the VsU Herbarium can safely be estimated at c. 800-1000. Given the small overall sampling area intensively studied so far these figures can be assumed as representing just a fraction of the total floristic richness of the area.

Unambiguous orientation in short fiber composites over small sampling area in a center-gated disk

A modified version of the method of ellipses was successfully developed, validated, and implemented to characterize short fiber orientation. Unambiguous orientation and a small sampling area were obtained by distinguishing between in-plane angles of ϕ and ϕ + π for every fiber and characterizing non-elliptical footprints, respectively. Measurements in two thin center-gated disks showed the existence of an asymmetric profile of orientation at the gate, which differs from the 3D random orientation commonly assumed in simulations. This profile washed out gradually at the entry region until disappearing at about 40% of flow length. A detailed set of orientation data for comparing fiber orientation to calculated values was obtained.

Diversity in genetic structure and chemotype composition of Fusarium graminearum sensu stricto populations causing wheat head blight in individual fields in Germany

Fusarium head blight (FHB) is one of the most destructive diseases of wheat. Twelve small commercial wheat fields (size 1–3 hectares) were sampled in Germany for Fusarium populations at three spots per field with 10 heads each. PCR assays using generic primers confirmed 338 isolates as F.graminearum sensu stricto (s.s.) (64.9%) out of 521 Fusarium spp. that were further analyzed. Populations of F. graminearum s.s. in Germany contain three types of trichothecenes with a dominancy of 15-acetyldeoxynivalenol chemotype (92%) followed by 3-acetyldeoxynivalenol chemotype (6.8%) and a few isolates of nivalenol chemotype (1.2%). All these isolates were genotyped using 19 microsatellite loci. The 12 populations showed a high genetic diversity within the small scale sampling areas resulting in 300 different haplotypes. Genetic diversity within populations (71.2%) was considerably higher than among populations (28.8%) as shown by analysis of molecular variance. Gene flow (Nm) between populations ranged from 0.76–3.16. Composition of haplotypes of one population followed over 2 years changed considerably. No correlation between genetic and geographical distance was found. In conclusion, populations of F. graminearum s.s. in Germany display a tremendous genetic variation on a local scale with a restricted diversity among populations.

Nanoscale structural characterization of epitaxial graphene grown on off-axis 4H-SiC (0001)

In this work, we present a nanometer resolution structural characterization of epitaxial graphene (EG) layers grown on 4H-SiC (0001) 8° off-axis, by annealing in inert gas ambient (Ar) in a wide temperature range (Tgr from 1600 to 2000°C). For all the considered growth temperatures, few layers of graphene (FLG) conformally covering the 100 to 200-nm wide terraces of the SiC surface have been observed by high-resolution cross-sectional transmission electron microscopy (HR-XTEM). Tapping mode atomic force microscopy (t-AFM) showed the formation of wrinkles with approx. 1 to 2 nm height and 10 to 20 nm width in the FLG film, as a result of the release of the compressive strain, which builds up in FLG during the sample cooling due to the thermal expansion coefficients mismatch between graphene and SiC. While for EG grown on on-axis 4H-SiC an isotropic mesh-like network of wrinkles interconnected into nodes is commonly reported, in the present case of a vicinal SiC surface, wrinkles are preferentially oriented in the direction perpendicular to the step edges of the SiC terraces. For each Tgr, the number of graphene layers was determined on very small sample areas by HR-XTEM and, with high statistics and on several sample positions, by measuring the depth of selectively etched trenches in FLG by t-AFM. Both the density of wrinkles and the number of graphene layers are found to increase almost linearly as a function of the growth temperature in the considered temperature range.

Advanced Neutron Reflectometer for Investigation on Dynamic/Static Structures of Soft-Interfaces in J-PARC

A novel neutron reflectometer with horizontal geometry will be established at BL16 in Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC) as a successor of a reflectometer ARISA-II. ARISA-II corresponding to a single neutron beam downward at 2.22 deg has achieved off-specular and time-resolved reflectivity measurements. The novel reflectometer is designed so as to receive two tilted neutron beams (2.22 & 5.71 deg), which gives us an opportunity in investigation on a free liquid surface. The reflectometer can provide a micro-sized beam by slit collimation and obtain a fair reflectivity with small sample area. Also, T0 chopper and neutron focusing mirror are newly introduced. The T0 chopper can suppress the background due to fast neutrons. The focusing mirror produces further reduction of measurement time not only for specular reflection by focusing neutrons on a sample, but also grazing incidence small-angle neutron scattering (GISANS) measurements by focusing on a detector.

Near Infrared Analysis of Fossil Bone from the Western Cape of South Africa

The burial environment of a fossil bone may be poorly suited to long-term preservation of important chemical constituents. Studies of fossil bone chemistry consequently benefit from knowledge of burial environmental change (burial history). Several techniques have been developed to describe alteration of fossil bone, including measurements of crystallinity using infrared spectroscopy. The utility of near infrared (NIR) spectroscopy was investigated for describing the burial history of fossil bone. Spectra from large sample areas (bulk NIR) identified secondary calcite and clay within fossil bone, and were useful for distinguishing fossils from different localities. Spectra from small sample areas (hyperspectral NIR) were used to map constituents within fossil bones. Calcite and clay pervaded the internal cavities of fossil horn cores, indicating saturation with groundwater. The identification and distribution of secondary minerals is relevant for studies of taphonomic process, hence NIR is a useful supplement to existing techniques for assessing the burial history of fossil bone.

Implications of scale, slope, tillage operation and direction in the estimation of surface depression storage

Many studies on soil microrelief, or roughness, have identified a multi-scale behaviour of roughness. However most of the literature on the surface storage of precipitation is based on experiments conducted over very small sampling areas, usually not large enough to reflect the large scale components of roughness. In this paper a 5m long surface roughness profile database is studied with the main objective of assessing the scaling behaviour of surface storage and the role that surface slope and tillage direction play on this phenomenon. In particular, in was evaluated whether the measurement domain size (profile length) and resolution (sampling interval) had any influence on the calculated storage values. Results illustrate a multiscale behaviour of surface storage, with larger storage values obtained for longer profiles and smaller sampling intervals. Tillage operations significantly affect observed storage values and their variability. Tillage direction also had a significant role in the calculated storage values, however its importance decreased clearly over areas of increasing slopes.

Recording and documenting the chromatic information of architectural heritage

Abstract One essential approach in preserving architectural heritage is the documentation of 3D geometries and surface textures of historic buildings. For example, precise colour information, excluding lighting effects, is an intrinsic property of the surface materials of building interiors and exteriors. However, while colour information has been recorded for small sample areas, it has not been accurately documented on the scale of entire building surfaces. This is critical, because building materials decay and their colours fade with time. The goal of this project is to develop a method to assist in recording and documenting the chromatic information of interiors and exteriors of historic buildings with low cost and high efficiency. The method takes advantage of emerging high dynamic range imaging (HDRI) technology, which can store rich information about colour and illumination through digital photography. By recording the colour information, in addition to the geometry and texture information obtained through other existing technologies, we can achieve more complete documentation for architectural heritage. In this paper, we discuss an overview of the problem and present our algorithms for utilizing computer vision techniques to retrieve chromatic information of historic buildings. We also present and discuss our experiments and results of applying our method to studies of lab objects and the Hall of Supreme Harmony in the Forbidden City, Beijing.

Landscape Genetics Reveals Focal Transmission of a Human Macroparasite

Macroparasite infections (e.g., helminths) remain a major human health concern. However, assessing transmission dynamics is problematic because the direct observation of macroparasite dispersal among hosts is not possible. We used a novel landscape genetics approach to examine transmission of the human roundworm Ascaris lumbricoides in a small human population in Jiri, Nepal. Unexpectedly, we found significant genetic structuring of parasites, indicating the presence of multiple transmission foci within a small sampling area (∼14 km2). We analyzed several epidemiological variables, and found that transmission is spatially autocorrelated around households and that transmission foci are stable over time despite extensive human movement. These results would not have been obtainable via a traditional epidemiological study based on worm counts alone. Our data refute the assumption that a single host population corresponds to a single parasite transmission unit, an assumption implicit in many classic models of macroparasite transmission. Newer models have shown that the metapopulation-like pattern observed in our data can adversely affect targeted control strategies aimed at community-wide impacts. Furthermore, the observed metapopulation structure and local mating patterns generate an excess of homozygotes that can accelerate the spread of recessive traits such as drug resistance. Our study illustrates how molecular analyses complement traditional epidemiological information in providing a better understanding of parasite transmission. Similar landscape genetic approaches in other macroparasite systems will be warranted if an accurate depiction of the transmission process is to be used to inform effective control strategies.

Inferring species abundance distribution across spatial scales

A long-standing problem in ecology is to understand how the species–abundance distribution (SAD) varies with sampling scale. The problem was first characterized by Preston as the veil line problem. Although theoretical and empirical studies have now shown the nonexistence of the veil line, this problem has generated much interest in scaling biodiversity patterns. However, research on scaling SAD has so far exclusively focused on the relationship between the SAD in a smaller sampling area and a known SAD assumed for a larger area. An unsolved challenge is how one may predict species–abundance distribution in a large area from that of a smaller area. Although upscaling biodiversity patterns (e.g. species–area curve) is a major focus of macroecological research, upscaling of SAD across scale is, with few exceptions, ignored in the literature. Methods that directly predict SAD in a larger area from that of a smaller area have just started being developed. Here we propose a Bayesian method that directly answers this question. Examples using empirical data from tropical forests of Malaysia and Panama are employed to demonstrate the use of the method and to examine its performance with increasing sampling area. The results indicate that only 10-15% of the total census area is needed to adequately predict species abundance distribution of a region. In addition to species abundance distributions, the method also predicts well the regional species richness.