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Small Scale (small + scale)
Kinds of Small Scale Selected AbstractsThe Behavior Engineering Model at Work on a Small Scale: Using Task Clarification, Self-Monitoring, and Public Posting to Improve Customer ServicePERFORMANCE IMPROVEMENT QUARTERLY, Issue 2 2001John Austin ABSTRACT Gilbert's (1978/1996) Behavior Engineering Model (BEM) can enable the success of novice performance engineers by prompting appropriate front-end analysis. This paper describes the third author's first performance improvement project conducted in the customer service department at an insurance agency. Front-end performance analysis informed the design of an intervention package that addressed particular environment and person variables. This package included task clarification, employee self-monitoring, and public posting of group performance. A multiple baseline design across behaviors was used to assess the effects of the intervention. The performance targets were: 1) the percentage of transactions where Customer Service Representatives (CSRs) used customer names, and 2) the percentage of transactions where CSRs suggested additional services available to customers. Average performance during intervention was more than 50% better than average baseline performance for both targets. Results are discussed in terms of the utility of the BEM as a front-end analysis tool that can guide novice performance engineers to build simple and inexpensive, yet effective, performance improvement interventions. [source] Quality of Life Outcomes for People with Intellectual Disabilities Living in Staffed Community Housing Services: a Stratified Random Sample of Statutory, Voluntary and Private Agency ProvisionJOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 1 2003Jonathan Perry Background, Small scale, community-based, staffed housing is a significant form of residential provision for people with intellectual disabilities. Such services are provided by health and local authorities, and voluntary and private agencies, yet little is known about how provision varies between provider sectors. Methods, This study compared sectors in terms of the processes operating within residential services, and objectively and subjectively assessed quality of life (QOL) resident outcomes. Measures of setting structure and processes and resident outcomes were undertaken on a stratified random sample of 47 small scale, community-based residential settings which accommodated a total of 154 people with intellectual disabilities. Results, In general, provider agencies did not differ in terms of the characteristics of the residents they served, the structure of settings, the processes underlying service operation or resident outcomes. However, across agencies there was considerable variation in residents' life conditions when they were measured objectively. Better outcome tended to be significantly correlated with the ability of residents. This was not the case with results on subjective measures (which were also higher than those on objective measures). Conclusions, The results reinforce the need to design services which effectively support people across the ability spectrum. Also, an argument is made for the continued utility of objective measurement in the assessment of service quality. [source] Comparing agglomerative clustering and three weed classification frameworks to assess the invasiveness of alien species across spatial scalesDIVERSITY AND DISTRIBUTIONS, Issue 6 2006Roger A. Lawes ABSTRACT To prioritize weed management at the catchment scale, information is required on the species present, their relatively frequency, abundance, and likely spread and impact. The objective of this study was to classify the invasiveness of alien species that have invaded the Upper Burdekin Catchment in Queensland, Australia, at three spatial scales. A combination of three published weed classification frameworks and multivariate techniques were employed to classify species based on their frequency and cover at a range of spatial scales. We surveyed the Upper Burdekin Catchment for alien species, and for each species determined the following distribution indices , site frequency, total cover, transect frequency per site frequency and quadrat frequency per site frequency, cover per quadrat when present, cover per transect when present, and cover per site when present. These indices capture the effect of species abundance and frequency between sites (site frequency and total cover), within sites (transect frequency per site and cover per transect when present), and within transects (quadrat frequency per site frequency and cover per site). They were used to classify the species into seven groups using a hierarchical cluster analysis. The relationship between the indices was explored to determine how effective the small scale, site-specific indices were at predicting the broader, landscape-scale patterns. Strong correlations were observed between transect frequency per site and frequency (r2 = 0.89) and cover per transect when present and total cover (r2 = 0.62). This suggests that if a weed is abundant at the site level, it has the potential to occupy large areas of the catchment. The species groupings derived from the application of the three published weed classification frameworks were compared graphically to the groupings derived from the cluster analysis. One of the frameworks classified species into three groups. The other two frameworks classified species into four groups. There was a high degree of subjectivity in applying the frameworks to the survey data. Some of the data were of no relevance to the classification frameworks and were therefore ignored. We suggest that the weed classification frameworks should be used in conjunction with existing multivariate techniques to ensure that classifications capture important natural variations in observed data that may reflect invasion processes. The combined use of the frameworks and multivariate techniques enabled us to aggregate species into categories appropriate for management. [source] Using geostatistics to elucidate temporal change in the spatial variation of aeolian sediment transportEARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2003Adrian Chappell Abstract Little is known about the spatial and temporal scales of variation in aeolian processes. Studies that aim to investigate surface erodibility often sample aeolian sediment transport at the nodes of a regular grid of arbitrary size. Few aeolian transport investigations have the resources to obtain sufficient samples to produce reliable models for mapping the spatial variation of transport. This study reports the use of an innovative nested strategy for sampling multiple spatial scales simultaneously using 40 sediment samplers. Reliable models of the spatial variation in aeolian sediment transport were produced and used for ordinary punctual kriging and stochastic simulated annealing to produce maps for several wind erosion events over a 25 km2 playa in western Queensland, Australia. The results support the existence of a highly dynamic wind erosion system that was responding to possibly cyclic variation in the availability of material and fluctuations in wind energy. The spatial scale of transport was considerably larger than the small scale expected of the factors controlling surface erodibility. Thus, it appears that transport cannot be used as a surrogate of erodibility at the scale of this investigation. Simulation maps of transport provided considerably more information than those from kriging about the variability in aeolian sediment transport and its possible controlling factors. The proposed optimal sampling strategy involves a nested approach using ca 50 samplers. Copyright © 2003 John Wiley & Sons, Ltd. [source] Corticolous arthropods under climatic fluctuations: compensation is more important than migrationECOGRAPHY, Issue 1 2005Andreas Prinzing Animals can cope with fluctuating climates by physiological tolerance, tracking of climatic fluctuations (migration) and compensatory redistribution among (micro)habitats (compensation). Compensation is less demanding and thus more important than migration at large geographic scales. It is not clear however which strategy is more important at the small scale of a microhabitat landscape. I investigated how six arthropod species (Collembola, Oribatei, Psocoptera, Isopoda) respond to microclimatic fluctuations at the surface of exposed tree trunks. Across a nine-month period I characterized the microclimatic zonation of 299 trunks, and focally sampled the arthropods from different microhabitat types (different cryptogam species and bark crevices) within different microclimatic zones. I found that compensatory microhabitat-use was a general phenomenon. The distribution of all species across microhabitats was influenced significantly by ambient microclimate. Also, the arthropods' microhabitat use changed throughout their ontogeny, and microhabitats were used even if they were rare. Most interestingly, the arthropods responded to microclimatic fluctuations primarily by redistribution among microhabitats and less by fluctuations of overall abundances across all microhabitats. Hence compensation was more important than migration. The animals moved for centimeters to decimeters rather than for decimeters to meters; they perceived and utilized their environment primarily at the finest, but also most complex scale. This has implications for the resilience of arthropod populations, their interactions with cryptogams and the turnover of species between macrohabitats. [source] Improved resolution with microchip-based enhanced field inversion electrophoresisELECTROPHORESIS, Issue 11 2003Christopher J. Backhouse Abstract We present an improvement of the field inversion electrophoresis (FIE) method in which the passage of sample such as DNA back and forth within a short length of a microchannel can provide a similar resolution to that of a significantly longer microchannel. In constant field FIE the application of an alternating potential (e.g., +/, V) over short periods of time (e.g., several Hz) can provide enhanced separations of DNA fragments. In contrast, the present method consists of a series of separations, each of much longer duration, under high and low fields in such a way that the resolution is enhanced. This method is readily modeled and allows improved resolution to be obtained from extremely short microchannels (e.g., 8 mm) while requiring relatively low applied voltages (e.g., less than 600 V). An additional advantage is that this method can allow for the same equipment to be used in a rapid, low-resolution mode or in a slower, high-resolution mode through what might be referred to as an automated "zoom" capability. We believe that this method may facilitate the integration of microfluidic devices and microelectronic devices by allowing these devices to be of a similar small scale (< 1 cm). [source] Can fishermen allocate their fishing effort in space and time on the basis of their catch rates?FISHERIES MANAGEMENT & ECOLOGY, Issue 1 2001An example from Spermonde Archipelago, Indonesia, SW Sulawesi Spatial and temporal patterns in catch rates and in allocation of fishing effort were analysed for the coastal fishery in Spermonde Archipelago, Indonesia, to assess whether fishermen can optimise their strategy from catch information, or whether they fish under great uncertainty and merely minimise risks. On average 517 fishing units operated in the 2800 km2 area, catching 21 t fish day,1. Major gear categories were hook and line (59% of total effort and 5% of total catch), and lift nets (16% of total effort and 70% of total catch). The size of individual resource spaces varied with gear type and was smaller in unfavourable weather conditions. Although spatial patterns in catch rates at the scale of the whole archipelago were evident, fishermen could not differentiate between locations, as catch variance within their individual resource spaces was high relative to the contrasts in spatial patterns. The aggregated distribution of fishing effort in Spermonde must be explained by factors such as the small scale of operations, rather than fish abundance. [source] Silica-Based, Organically Modified Host Material for Waveguide Structuring by Two-Photon-Induced PhotopolymerizationADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Stefan Krivec Abstract The three-dimensional fabrication of optical waveguides has gained increasing interest in recent years to establish interconnections between electrical components on a very small scale where copper circuits encounter severe limitations. In this work the application of optically clear, organically modified porous silica monoliths and thin films as a host material for polymeric waveguides to be inscribed into the solid host structure by two-photon-induced photopolymerization is investigated. Porosity is generated using a lyotropic liquid crystalline surfactant/solvent system as a template for the solid silica material obtained by a sol,gel transition of a liquid precursor. In order to reduce the brittleness of the purely inorganic material, organic,inorganic co-precursor molecules that contain poly(ethylene glycol) chains are synthesized and added to the mixture, which successfully suppresses macroscopic cracking and leads to flexible thin films. The structure of the thus-obtained porous organic,inorganic hybrid material is investigated by atomic force microscopy. It is shown that the modified material is suitable for infiltration with photocurable monomers and functional polymeric waveguides can be inscribed by selective two-photon-induced photopolymerization. [source] Testing species,stone area and species,bryophyte cover relationships in riverine macroinvertebrates at small scalesFRESHWATER BIOLOGY, Issue 3 2008JANI HEINO Summary 1. The species,area relationship is considered amongst the few genuine laws in ecology. Although positive species richness,stone area relationships have been found previously in stream systems, very few studies have simultaneously examined species,individuals, individuals,area, species,bryophyte biomass and individuals,bryophyte biomass relationships. We examined these relationships based on temporally replicated assessments of macroinvertebrates on stones at two river sites. 2. We found only one significant species,area relationship out of six relationship tested, and two significant individuals,area relationships. Even these significant relationships were weak, however. By contrast, we detected significant and rather strong relationships between species richness and the number of individuals at both river sites on all three sampling dates. We also found significant relationships of both species richness and the number of individuals with bryophyte biomass at both river sites on all sampling occasions. One of the river sites was disturbed by a bulldozer, and the species,bryophyte biomass relationships were somewhat stronger after the disturbance event. 3. Our findings are quite surprising, given that there were very weak species,area relationships on stream stones. By contrast, our results suggest a pivotal role for bryophyte biomass in determining the species richness and the number of individuals of stream macroinvertebrates at this small scale. The most probably origin of these relationships begins with bryophyte cover, which determines the number of individuals, and subsequently passively affects species richness. Thus, there is not necessarily a direct mechanism that determines the variability of species richness on stream stones. 4. Experimental studies are needed to disentangle the various mechanisms (e.g. passive sampling, provision of more food, more niche space, flood disturbance refugia) by which bryophyte biomass affects stream macroinvertebrates. [source] Enhanced exoenzyme activities in sediments in the presence of deposit-feeding Chironomus riparius larvaeFRESHWATER BIOLOGY, Issue 9 2007PETER STIEFArticle first published online: 10 JUN 200 Summary 1. The combined effects of deposit-feeding, bioturbation and bioirrigation by benthic macrofauna on the enzymatic hydrolysis of organic matter were studied in microcosms. Chironomus riparius larvae (Insecta, Diptera) served as model macrofauna and stinging nettle leaves (Urtica dioica) were used as a detrital food source. 2. In the upper 10 mm of the sediment (the habitat of C. riparius larvae), the activities of several exoenzymes, the contents of several fractions of particulate organic matter (POM), and the concentrations of dissolved oxidants (O2, NO) were measured on a small scale. Fluorescent particles (luminophores) were used to quantify the vertical redistribution of particles within the same layer. 3. In control sediment, the addition of detrital food enhanced exoenzyme activities in the 0,2 mm layer only. In the presence of C. riparius larvae, exoenzyme activities increased to 10 mm depth. Further, the content of POM in the 0,2 mm layer was lower in the presence than in the absence of larvae, suggesting ingestion and subduction of the added detritus. After prolonged incubation without further food addition, exoenzyme activities returned close to background values in both treatments, whereas the vertical distribution of POM remained unchanged. 4. The overall penetration depth of O2 and NO into the sediment was greater in the presence than the absence of C. riparius, the differences being more pronounced after prolonged incubation. Locally high O2 and NO concentrations due to bioirrigation by C. riparius were measured deep in the sediment. Net downward transport of particles was observed only in the presence of C. riparius larvae and only at the beginning of the incubation. 5. I conclude that deposit-feeding and bioturbation by macrofauna can quickly remove freshly deposited POM from the sediment surface and transfer it to less oxygenated sites (i.e. animal guts and deep sediment layers). Bioirrigation also increases the availability of oxidants deep in the sediment. The oscillation of oxidant supply to POM particles by ingestion,egestion, burial and re-burial, and the intermittent bioirrigation of subsurface sediment, is probably the cause of the increased rate of organic matter hydrolysis, the rate-limiting step in mineralization. [source] Wind erosion and intensive prehistoric agriculture: A case study from the Kalaupapa field system, Moloka'i Island, Hawai'iGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 5 2007Mark D. McCoy Wind erosion is a major problem for modern farmers, a key variable affecting nutrient levels in ecosystems, and a potentially major force impacting archaeological site formation; however, it has received scant consideration in geoarchaeological studies of agricultural development compared with more easily quantifiable environmental costs, such as vegetation change or fluvial erosion. In this study, soil nutrient analysis is used in the Kalaupapa field system, Moloka'i Island, Hawai'i, to detect an increase in wind erosion attributable to intensive agriculture following the burning of endemic forest. This practice began on a small scale in the 13th century A.D., expanded around cal A.D. 1450,1550, and continued until the near total abandonment of the fields after European contact in the 18th century. Nutrients that naturally occur in high amounts in coastal windward areas due to the long-term, cumulative effect of sea spray were especially impacted. However, thanks to the unique landform of the Kalaupapa Peninsula, nutrient depletion in windward areas was offset by downwind enrichment and likely contributed to the long-term sustainability of the system as a whole. Future research on tropical and arid agriculture should consider the cumulative environmental cost of increased eolian erosion attributable to anthropogenic landscape modification. © 2007 Wiley Periodicals, Inc. [source] Micro-scale sulphur isotope evidence for sulphur cycling in the late Archean shallow oceanGEOBIOLOGY, Issue 1 2007B. S. KAMBER ABSTRACT We report in situ secondary ion mass spectrometer sulphur isotope data for sedimentary pyrite from the 2.52 Ga Upper Campbellrand Subgroup, Transvaal, South Africa. The analysed sedimentary rocks represent a transition in depositional environment from very shallow to deeper water, with strong sedimentological, facies distribution and geochemical evidence for the presence of a shallow redox chemocline. Data were obtained directly in thin section in order to preserve petrographic context. They reveal a very large extent of isotopic fractionation both in mass-independent (MIF) and in mass-dependent fractionation (MDF) on unprecedentedly small scale. In the shallow-water microbical carbonates, three types of pyrite were identified. The texturally oldest pyrite is found as small, isotopically little fractionated grains in the microbial mats. Large (several mm) spheroidal pyrite concretions, which postdate the mat pyrite, record strong evidence for an origin by bacterial sulphate reduction. Rare pyrite surrounding late fenestral calcite is inferred to have formed from recycled bacterial pyrite on account of the slope of its correlated MIF and MDF array. This latter type of pyrite was also found in an interbedded black shale and a carbonate laminite. In a deeper water chert, pyrite with very heavy sulphur indicates partial to almost complete sulphate reduction across a chemocline whose existence has been inferred independently. The combined picture from all the studied samples is that of a sulphate availability-limited environment, in which sulphur was cycled between reservoirs according to changing redox conditions established across the chemocline. Cycling apparently reduced the extent of recorded sulphur isotope fractionation relative to what is expected from projection in the correlated MIF and MDF arrays. This is consistent with regionally relatively high free oxygen concentrations in the shallow water, permitting locally strong MDF. Our new observations add to the growing evidence for a complex, fluctuating evolution of free atmospheric oxygen between c. 2.7 Ga and 2.3 Ga. [source] Scattering behaviour at Merapi volcano (Java) revealed from an active seismic experimentGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2001Ulrich Wegler SUMMARY The seismic structure of the stratovolcano Merapi (Java, Indonesia) was studied using an active seismic experiment. Three 3 km long seismic profiles each consisting of up to 30 three-component seismometers with an interstation distance of 100 m were built up in an altitude range between 1000 and 2000 m above sea level. The detailed study of the seismic properties of the propagation media in active volcanic regions is important to understand the natural seismic signals used for eruption forecasting. The seismic experiment at Merapi therefore concentrates on the heterogeneous structure within a radius of 5 km from the active dome, where the sources of most of the natural volcanic seismic events are located. The cone of Merapi volcano consists of different materials changing on a small scale due to the layering of eruptive material. Additionally, the topography of the erosion valleys leads to an irregular deposition, which cannot be described by a simple 1-D layering. These inhomogeneities have a strong influence on seismic signals. The direct P and S waves are attenuated quickly and show only small amplitudes on seismograms. The energy lost from the direct waves, however, is not changed into heat but scattered and can be observed as seismic coda following the direct waves. The observed seismograms show a spindle-like amplitude increase after the direct P phase. This shape of the envelope can be explained by the diffusion model. According to this model there are so many strong inhomogeneities that the direct wave can be neglected and all energy is concentrated in multiple scattered waves. Besides the envelope, the coherence and polarization properties of the wavefield also indicate strong scattering. Only the first onset shows coherence over a station spacing of 100 m, whereas the late phases carrying the major part of the energy are mainly incoherent. The horizontal components of the seismograms have larger amplitudes than the vertical component, but within the horizontal plane the polarization is almost arbitrary, corresponding to waves arriving from scatterers located arbitrarily in space. As a result of the inversion using the diffusion model we obtain values of the S -wave scattering attenuation coefficient, ,s, and the S -wave intrinsic absorption coefficient, ,i. In the frequency range of 4,20 Hz used in this study the scattering attenuation is at least one order of magnitude larger than the intrinsic absorption (,s,,i). The mean free path of S waves is as low as 100 m (,s,1,100 m). The scattering coefficient is independent of frequency (,s,f0.0), whereas the coefficient of intrinsic attenuation increases with increasing frequency (,i,f1.6). The natural seismic signals at Merapi volcano show similar characteristics to the artificial shots. The first onsets have only small amplitudes and the energy maximum arrives delayed compared to the direct waves. Therefore, these signals appear to be strongly affected by multiple scattering also. [source] Different methods for modelling the areal infiltration of a grass field under heavy precipitationHYDROLOGICAL PROCESSES, Issue 7 2002Bruno Merz Abstract The areal infiltration behaviour of a grass field is studied using a data set of 78 sprinkler infiltration experiments. The analysis of the experimental data shows a distinct event dependency: once runoff begins, the final infiltration rate increases with increasing rainfall intensity. This behaviour is attributed to the effects of small-scale variability. Increasing rainfall intensity increases the ponded area and therefore the portion of the plot which infiltrates at maximum rate. To describe the areal infiltration behaviour of the grass field the study uses two different model structures and investigates different approaches for consideration of subgrid variability. It is found that the effective parameter approach is not suited for this purpose. A good representation of the observed behaviour is obtained by using a distribution function approach or a parameterization approach. However, it is not clear how the parameters can be derived for these two approaches without a large measurement campaign. The data analysis and the simulations show the great importance of considering the effects of spatial variability for the infiltration process. This may be significant even at a small scale for a comparatively homogeneous area. The consideration of heterogeneity seems to be more important than the choice of the model type. Furthermore, similar results may be obtained with different modelling approaches. Even the relatively detailed data set does not seem to permit a clear model choice. In view of these results it is questionable to use very complex and detailed simulation models given the approximate nature of the problem. Although the principle processes may be well understood there is a lack of models that represent these processes and, more importantly, there is a lack of techniques to measure and parameterize them. Copyright © 2002 John Wiley & Sons, Ltd. [source] Localized electrical current propagation in anisotropically perturbed atmospheresINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 1 2010T. I. ZohdiArticle first published online: 29 MAR 2010 Abstract The trajectory of free atmospheric electrical currents, such as lightning and sparks, is strongly influenced by microscale events that occur at the current front. In particular, highly conductive pathways can occur at the free surface front due to dielectric breakdown. The specific directions of the local pathways are minutely perturbed, due to the gaseous, disordered, nature of the media at the small scale. This results in highly conductive, anisotropically perturbed, continuum-level properties at the electrical current front. In this work, a model is developed to investigate the role of the resulting anisotropically perturbed conductivity at the propagation front on the overall trajectory of free atmospheric electrical currents. The approach is to relate the electrical current velocity to the local anisotropic conductivity at the propagation front and the surrounding electric field. The conductive anisotropy is decomposed into an isotropic ,base state' and an anisotropic perturbation. The current trajectory is shown to be governed by a set of non-linear differential equations, for which a numerical solution scheme is developed. The difference between paths taken through anisotropically perturbed and isotropic media is analytically bounded and quantified numerically as a function of the magnitude of the anisotropic perturbation. The analysis and numerical experiments indicate that, in a statistical sense, the difference in the paths taken in anisotropically perturbed and isotropic media depends quasilinearly on the perturbation magnitude. Copyright © 2010 John Wiley & Sons, Ltd. [source] Ethnic skin types: are there differences in skin structure and function?,INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2006A. V. Rawlings Synopsis People of skin of colour comprise the majority of the world's population and Asian subjects comprise more than half of the total population of the earth. Even so, the literature on the characteristics of the subjects with skin of colour is limited. Several groups over the past decades have attempted to decipher the underlying differences in skin structure and function in different ethnic skin types. However, most of these studies have been of small scale and in some studies interindividual differences in skin quality overwhelm any racial differences. There has been a recent call for more studies to address genetic together with phenotypic differences among different racial groups and in this respect several large-scale studies have been conducted recently. The most obvious ethnic skin difference relates to skin colour which is dominated by the presence of melanin. The photoprotection derived from this polymer influences the rate of the skin aging changes between the different racial groups. However, all racial groups are eventually subjected to the photoaging process. Generally Caucasians have an earlier onset and greater skin wrinkling and sagging signs than other skin types and in general increased pigmentary problems are seen in skin of colour although one large study reported that East Asians living in the U.S.A. had the least pigment spots. Induction of a hyperpigmentary response is thought to be through signaling by the protease-activated receptor-2 which together with its activating protease is increased in the epidermis of subjects with skin of colour. Changes in skin biophysical properties with age demonstrate that the more darkly pigmented subjects retaining younger skin properties compared with the more lightly pigmented groups. However, despite having a more compact stratum corneum (SC) there are conflicting reports on barrier function in these subjects. Nevertheless, upon a chemical or mechanical challenge the SC barrier function is reported to be stronger in subjects with darker skin despite having the reported lowest ceramide levels. One has to remember that barrier function relates to the total architecture of the SC and not just its lipid levels. Asian skin is reported to possess a similar basal transepidermal water loss (TEWL) to Caucasian skin and similar ceramide levels but upon mechanical challenge it has the weakest barrier function. Differences in intercellular cohesion are obviously apparent. In contrast reduced SC natural moisturizing factor levels have been reported compared with Caucasian and African American skin. These differences will contribute to differences in desquamation but few data are available. One recent study has shown reduced epidermal Cathepsin L2 levels in darker skin types which if also occurs in the SC could contribute to the known skin ashing problems these subjects experience. In very general terms as the desquamatory enzymes are extruded with the lamellar granules subjects with lowered SC lipid levels are expected to have lowered desquamatory enzyme levels. Increased pores size, sebum secretion and skin surface microflora occur in Negroid subjects. Equally increased mast cell granule size occurs in these subjects. The frequency of skin sensitivity is quite similar across different racial groups but the stimuli for its induction shows subtle differences. Nevertheless, several studies indicate that Asian skin maybe more sensitive to exogenous chemicals probably due to a thinner SC and higher eccrine gland density. In conclusion, we know more of the biophysical and somatosensory characteristics of ethnic skin types but clearly, there is still more to learn and especially about the inherent underlying biological differences in ethnic skin types. Résumé, Les gens qui ont une peau de couleur représentent la majorité de la population mondiale et les sujets asiatiques en représentent plus de la moitié. Pourtant la littérature consacrée aux caractéristiques de ces sujets est limitée. Plusieurs groupes de travail ont essayé au cours des dernières années de comprendre les différences sous-jacentes de la structure et de la fonction de la peau de différentes ethnies. Maisla plupart de ces études ont été réalisées à petite échelle et dans certains cas les différences observées entre les individus au niveau de la qualité de la peau ne font pas ressortir de différence entre races. Récemment, un besoin d'études reliant les diffèrences génétiques et phénotypiques entre différents groupes raciaux s'est fait sentir et de ce fait beaucoup d'études à grande èchelle ont été entreprises. La différence la plus évidente, entre les peaux ethniques, est leur couleur liée à la présence de la mélanine. La photoprotection induite par ce polymère influence le taux de vieillissement de la peau entre les différents groupes raciaux qui finalement sont tous sujets au processus de photovieillissement. Généralement, les caucasiens ont des signes plus précoces et plus importants de formation de rides et de relâchement de la peau; en général, les problèmes d'augmentation de la pigmentation sont observés sur les peaux de couleur, bien qu'une grande étude ait rapporté que des sujets originaires de l'Asie de l'Est vivant aux U.S.A. avaient le moins de taches pigmentaires. On pense que la réponse d'une induction hyperpigmentaire est due à un signal envoyé par le récepteur 2 activé par une protéase. Le récepteur 2 augmente en même temps que la protéase activatrice dans l'épiderme des sujets ayant une peau de couleur. Les changements dans les propriètés biophysiques de la peau en fonction de l'âge montrent que les sujets qui ont la pigmentation la plus sombre gardent une peau plus jeune par comparaison aux groupes qui possèdent une pigmentation moins forte. Toutefois, bien qu'ayant un stratum corneum plus compact, il existe des rapports divergents sur la fonction barrière de ces sujets. Dans le cas d'agression chimique ou mécanique, la fonction barrière du stratum corneum est considérée plus forte chez les sujets à peau plus foncée, malgré leurs taux plus faibles encéramide. On doit garder à l'esprit que la fonction barrière du stratum corneum dépend de toute son architecture et pas seulement de sa teneur en lipides. On considère que la peau asiatique à unePIE (TEWL) basale similaire à la peau caucasienne, ainsi que des taux en céramides comparables, mais on constate que dans le cas d'agression mécanique, elle possède un effet barrière le plus faible. Des différences dans la cohésion intercellulaire sont évidentes. A contrario, on a mis en évidence des taux d'hydratation (NMF) plus faibles dans son stratum corneum, comparativement à la peau caucasienne et afro-américaine. Ces différences expliquent les variations au niveau de la desquamation, mais on a très peu de données sur ce sujet. Une étude récente a mis en évidence des taux réduits de Cathepsin L2 dans l'épiderme des types de peau plus sombre, ce qui, si cela se produisait dans le stratum corneum, expliquerait les problèmes biens connus de cendrage de la peau que ces sujets connaissent. En terme très gènéral, étant donné que les enzymes liées à la desquamation sont libérées avec les granules lamellaires, on s'attend à ce que les sujets ayant des taux de lipides faibles dans le stratum corneum aient des taux d'enzymes liés à la desquamation faibles. On constate chez les sujets noirs une augmentation de la taille des pores, de la sécrétion du sébum et de la microflore cutanée. On observe également chez ces sujets une augmentation de la taille des granules mastocellulaires. Le phénomène de peau sensible se retrouve à une fréquence similaire dans les différents groupes raciaux, mais il existe des différences subtiles dans lesstimuli nécessaires pour l'induire. En tout cas, plusieurs études montrent que la peau asiatique est peut-être plus sensible aux produits chimiques exogènes, ce qui probablement est dûà un stratum corneum plus mince et à une densité de glandes eccrines plus élevées. En conclusion, c'est sur les caractéristiques biophysiques et somato-sensorielles des différents types de peaux ethniques que nous en savons plus, mais il est clair qu'il nous reste à comprendre encore beaucoup de choses principalement sur leurs différences biologiques. [source] Factors Affecting Macroinvertebrate Richness and Diversity in Portuguese Streams: a Two-Scale AnalysisINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 2 2004Manuel A. S. Graça Abstract We analysed the spatial patterns in macroinvertebrate taxon richness and abundance at two scales: sampling unit and basin. We sampled 12 stream sites in three zones of Portugal, differing in climate geomorphology and water chemistry. At a sampling unit scale, substratum organic matter content, depth and the dominant size of substratum particles were correlated with numbers of taxa and individuals. We propose that the number of taxa at a small scale depends on the number of individuals, which in turn is the result of organic matter accumulation, hydrologic and substratum characteristics. The environmental parameters better explaining the large-scale biological data were temperature, minimum size of substratum particles and pH. Regardless of the relative importance of variable types and mechanisms regulating stream invertebrates along the climatic gradient, rivers from the North and Centre appeared to be richer in taxa than the typically Mediterranean streams in the South. [source] Epidermal differentiation in embryos of the tuatara Sphenodon punctatus (Reptilia, Sphenodontidae) in comparison with the epidermis of other reptilesJOURNAL OF ANATOMY, Issue 1 2007L. Alibardi Abstract Studying the epidermis in primitive reptiles can provide clues regarding evolution of the epidermis during land adaptation in vertebrates. With this aim, the development of the skin of the relatively primitive reptile Sphenodon punctatus in representative embryonic stages was studied by light and electron microscopy and compared with that of other reptiles previously studied. The dermis organizes into a superficial and deep portion when the epidermis starts to form the first layers. At embryonic stages comparable with those of lizards, only one layer of the inner periderm is formed beneath the outer periderm. This also occurs in lizards and snakes so far studied. The outer and inner periderm form the embryonic epidermis and accumulate thick, coarse filaments (25,30 nm thick) and sparse alpha-keratin filaments as in other reptiles. Beneath the embryonic epidermis an oberhautchen and beta-cells form small horny tips that represent overlapping borders along the margin of beta-cells that overlap other beta-cells (in a tile-like arrangement). The tips resemble those of agamine lizards but at a small scale, forming a lamellate-spinulated pattern as previously described in adult epidermis. The embryonic epidermis matures by the dispersion of coarse filaments among keratin at the end of embryonic development and is shed around hatching. The presence of these matrix organelles in the embryonic epidermis of this primitive reptile further indicates that amniote epidermis acquired interkeratin matrix proteins early for land adaptation. Unlike the condition in lizards and snakes, a shedding complex is not formed in the epidermis of embryonic S. punctatus that is like that of the adult. Therefore, as in chelonians and crocodilians, the epidermis of S. punctatus also represents an initial stage that preceded the evolution of the shedding complex for moulting. [source] Monitoring and regulation of marine aquaculture in DenmarkJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4-5 2000P. B. Pedersen Summary Marine fish farming in Denmark is completely dominated by the farming of large rainbow trout (Oncorhynchus mykiss) of 2,5 kg/piece in net cages or land-based flow-through systems, even though more species are being farmed on a small scale. The Danish production of rainbow trout in sea water reached some 8500 tonnes in 1998, and is unlikely to increase due to new restrictions imposed by the Ministry of Environment and Energy, including a provisional stop for extensions and new establishments. This prohibition was put in force in spite the fact that overall outlets are well below the frame allocated for marine fish farming. Generally, the procedures for obtaining allowances are complicated, involving regional and national institutions as well as public hearings. The procedures are described in this article. [source] Synthesis and crystallization behavior of acetal copolymer/silica nanocomposite by in situ cationic ring-opening copolymerization of trioxane and 1,3-dioxolaneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2008Lanhui Sun Abstract The acetal copolymer/silica nanocomposite was prepared by in situ bulk cationic copolymerization of trioxane and 1,3-dioxolane in the presence of nanosilica. The crystallization behavior of acetal copolymer/silica nanocomposite was studied by AFM, DSC, XRD, and CPOM, and the macromolecular structure of acetal copolymer/silica nanocomposite was characterized by FTIR and 1H-NMR. The 1H-NMR results showed that the macromolecular chain of acetal copolymer had more than two consecutive 1,3-dioxolane units in an oxymethylene main chain, while that of acetal copolymer/silica nanocomposite had only one 1,3-dioxolane unit in an oxymethylene main chain. There existed interaction between the macromolecular chains and nanoparticles (such as hydrogen bonds and coordination). On one hand, nanoparticles acted as nucleation center, which accelerated the crystallization rate but reduced the crystallinity. The spherulite sizes also decreased with addition of nanoparticles attributed to the nucleation effect. On the other hand, the presence of nanoparticles interrupted the spherical symmetry of the crystallite. In conclusion, the high surface energy and small scale of nanoparticles have a prominent impact on the polymerization mechanism and crystallization behavior of nanocomposite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Quality of Life Outcomes for People with Intellectual Disabilities Living in Staffed Community Housing Services: a Stratified Random Sample of Statutory, Voluntary and Private Agency ProvisionJOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 1 2003Jonathan Perry Background, Small scale, community-based, staffed housing is a significant form of residential provision for people with intellectual disabilities. Such services are provided by health and local authorities, and voluntary and private agencies, yet little is known about how provision varies between provider sectors. Methods, This study compared sectors in terms of the processes operating within residential services, and objectively and subjectively assessed quality of life (QOL) resident outcomes. Measures of setting structure and processes and resident outcomes were undertaken on a stratified random sample of 47 small scale, community-based residential settings which accommodated a total of 154 people with intellectual disabilities. Results, In general, provider agencies did not differ in terms of the characteristics of the residents they served, the structure of settings, the processes underlying service operation or resident outcomes. However, across agencies there was considerable variation in residents' life conditions when they were measured objectively. Better outcome tended to be significantly correlated with the ability of residents. This was not the case with results on subjective measures (which were also higher than those on objective measures). Conclusions, The results reinforce the need to design services which effectively support people across the ability spectrum. Also, an argument is made for the continued utility of objective measurement in the assessment of service quality. [source] Volatile fatty acid production during anaerobic mesophilic digestion of solid potato wasteJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2004Wilson Parawira Abstract The production of volatile fatty acids by anaerobic digestion of solid potato waste was investigated using a batch solid waste reactor with a working capacity of 2 dm,3 at 37°C. Solid potato waste was packed into the digester and the organic content of the waste was released by microbial activity by circulating water over the bed, using batch loads of 500 g or 1000 g potato waste. The sequence of appearance of the volatile fatty acids was (acetic, propionic); (n -butyric); (n -valeric, iso-valeric, caproic); (iso-butyric). After 300 h digestion of potato waste on a small scale, the fermentation products were chiefly (mg g,1 total VFAs): acetic acid (420), butyric acid (310), propionic acid (140) and caproic acid (90), with insignificant amounts of iso-butyric acid, n -valeric and iso-valeric acids. When the load of potato solids was increased, the volatile fatty acid content was similar, but butyric acid constituted 110 mg g,1 and lactic acid 400 mg g,1 of the total volatile fatty acids. The maximum soluble chemical oxygen demand (COD) achieved under the experimental conditions used was 27 and 37 g COD dm,3 at low and high loadings of potato solids, respectively. The total volatile fatty acids reached 19 g dm,3 of leachate at both loads of potato solid waste. Gas production was negligible, indicating that methanogenic activity was effectively inhibited. Copyright © 2004 Society of Chemical Industry [source] Fine-scale spatial structure in a grassland community: quantifying the plant's-eye viewJOURNAL OF ECOLOGY, Issue 1 2002D. W. Purves Summary 1The fine-scale spatial patterns of Agrostis stolonifera, Holcus lanatus and Lolium perenne were recorded in an English lowland grassland as presence/absence maps from 400-cell quadrats at two different scales (2 × 2 cm or 8 × 8 cm cells). 2Local spatial structure in these patterns was quantified using spatial covariance functions. Distance- and direction-dependent components were examined separately for both intra- and interspecific patterns. The significance of departures from randomness was determined using Monte Carlo techniques. 3The smaller-scale data showed that all three species were significantly aggregated, Agrostis to a greater distance (8 cm) than Holcus or Lolium(4 cm). The intensity of aggregation decreased in the order Lolium > Holcus > Agrostis. The larger-scale data suggested that this aggregation extended to greater distances, and that it was most intense in Agrostis. 4Despite the lack of visual directionality in the environment, Agrostis showed a directional pattern at both scales, with Lolium varying in the same direction at the larger scale. 5Only Agrostis and Lolium showed a significant interspecific relationship (segregated to 2 cm at the small scale, but aggregated to 8 cm at the larger scale). There was no evidence of directionality in the interspecific components of pattern. 6The nature of spatial structure appears to depend on the scale of observation, but the smaller-scale data are more likely to provide a biologically interpretable measure of local spatial structure in this community. [source] Structure of the skin of an air-breathing mudskipper, Periophthalmus magnuspinnatusJOURNAL OF FISH BIOLOGY, Issue 6 2002J. Y. Park The epidermis of the mudskipper Periophthalmus magnuspinnatus consisted of three layers: the outermost layer, middle layer and stratum germinativum. Extensive vascular capillary networks were present near the superficial layer of epidermis and outermost layer. The diffusion distance between the vascular capillaries and the surface of epidermis was c. 1.5 ± 0.9,m. The middle layer consisted of small or voluminous cells swollen by epidermal cells. Due to the swollen cells, the thickness of the epidermis increased and the epidermis appeared web-like. The swollen cells contained tonofilaments, lucent contents and desmosomes. Fine blood capillaries were also discernible in this layer. Well-developed lymphatic spaces containing lymphocytes existed in the stratum germinativum. Numerous blood capillaries were present under the basement membrane. The dermis consisted of a stratum laxum and stratum compactum, and there was a definite area with acid mucopolysaccharides and a small scale in the stratum laxum. The skin had an epidermal pigment cell, dendritic melanophores (-cytes) containing melanin granules within their cytoplasm, and two kinds of dermal pigment cells, melanophores and colourless pigments containing reflecting platelets. [source] Marginal Land-based Biomass Energy Production in ChinaJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 1 2010Ya Tang Fast economic development in China has resulted in a significant increase in energy demand. Coal accounts for 70% of China's primary energy consumption and its combustion has caused many environmental and health problems. Energy security and environmental protection requirements are the main drivers for renewable energy development in China. Small farmland and food security make bioenergy derived from corn or sugarcane unacceptable to China: the focus should be on generating bioenergy from ligno-cellulosic feedstock sources. As China cannot afford biomass energy production from its croplands, marginal lands may play an important role in biomass energy production. Although on a small scale, marginal land has already been used for various purposes. It is estimated that some 45 million hm2 of marginal land could be brought into high potential biomass energy production. For the success of such an initiative, it will likely be necessary to develop multipurpose plants. A case study, carried out on marginal land in Ningnan County, Sichuan Province with per capita cropland of 0.07 ha, indicated that some 380 000 tons of dry biomass could be produced each year from annual pruning of mulberry trees. This study supports the feasibility of producing large quantities of biomass from marginal land sources. [source] Synergistic routes to liquid fuel for a petroleum-deprived futureAICHE JOURNAL, Issue 7 2009Rakesh Agrawal Abstract When compared with biomass gasification/Fischer-Tropsch synthesis, hydropyrolysis/hydrodeoxygenation (HDO)-based processes have a potential to achieve high biomass carbon conversion to liquid fuel with much lower amounts of supplementary H2. On the basis of this observation, we suggest a Hydrogen Bio-oil (H2Bioil) process using fast hydropyrolysis/HDO that has a potential to produce nearly double the amount of liquid fuel when compared with the existing biofuel processes while requiring only modest quantities of supplementary H2. The optimal operating mode for the H2Bioil process is suggested to be in an entrained bed mode in presence of H2 with gas phase HDO of hydropyrolyzed vapors. A remarkable result due to reduced need for the supplementary H2 is that it provides synergistic integration of the H2Bioil process with a coal gasification power plant or a small scale steam natural gas (NG) reformer leading to a dramatic increase in the liquid fuel production from biomass and coal or NG. Here, hot synthesis gas (T>500°C) from a coal gasifier or methane reformer supplies H2/CO for hydropyrolysis and deoxygenation as well as heat for the process. This result is exciting, because it presents us with an option to build integrated H2Bioil processes sooner rather than later when the cost effective H2 becomes available from a carbon-free energy source such as solar or nuclear. The H2Bioil process and its integrated version with a small scale NG reformer have strong potential to be attractive on a small scale while being more efficient than any current biomass to liquid fuel process in operation. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Accuracy of scale conceptions in science: Mental maneuverings across many orders of spatial magnitudeJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 10 2006Thomas R. Tretter The use of unifying themes that span the various branches of science is recommended to enhance curricular coherence in science instruction. Conceptions of spatial scale are one such unifying theme. This research explored the accuracy of spatial scale conceptions of science phenomena across a spectrum of 215 participants: fifth grade, seventh grade, ninth grade, twelfth grade, and doctoral students in science. Conceptions spanning sizes from one nanometer to one billion meters were investigated through use of written assessments and individual interviews. Results showed that accuracy of conceptions at small scale were not symmetrical with respect to conceptions at large scale. Large scale accuracy tended to decline in a smooth, uniform fashion as the scale increased, whereas small scale accuracy displayed a discontinuity at the microscopic level. To conceptually interact with scales far removed from human scale, experts used strategies of mentally jumping to a new scale-world. Experts tended not to transition smoothly between the differently scaled worlds but rather to make a discontinuous leap, maintaining abstract linkages between the worlds via mathematics. Implications of these findings for curriculum development and classroom instruction are discussed. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 1061,1085, 2006 [source] A two-scale model for liquid-phase epitaxyMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 1 2009Ch. Eck Abstract We study a model for liquid-phase epitaxy that is based on a continuum description of the transport processes in the liquid and a Burton,Cabrera,Frank (BCF) model for the growth of the solid by epitaxy. In order to develop a model that is capable to incorporate structures of a very small scale in the solid phase within a computation for a technically relevant macroscopic length scale, we apply homogenization methods. The result of the homogenization procedure is a two-scale model that consists of macroscopic equations for fluid flow and solute diffusion in the fluid volume, coupled to microscopic BCF models for the evolution of the microstructure in the solid phase. The obtained two-scale model is justified by an estimate for the model error that is valid under appropriate assumptions on the regularity of the solutions. This estimate is proved for a phase field approximation of the BCF model. Copyright © 2008 John Wiley & Sons, Ltd. [source] Co-occurrence in nature of different clones of the social amoeba, Dictyostelium discoideumMOLECULAR ECOLOGY, Issue 4 2003A. Fortunato Abstract The social amoeba, Dictyostelium discoideum, produces a multicellular fruiting body and has become a model system for cell,cell interactions such as signalling, adhesion and development. However, unlike most multicellular organisms, it forms by aggregation of cells and, in the laboratory, forms genetic chimeras where there may be competition among clones. Here we show that chimera formation is also likely in nature, because different clones commonly co-occur on a very small scale. This suggests that D. discoideum will likely have evolved strategies for competing in chimeras, and that the function of some developmental genes will be competitive. Natural chimerism also makes D. discoideum a good model organism for the investigation of issues relating to coexistence and conflict between cells. [source] Habitat differentiation vs. isolation-by-distance: the genetic population structure of Elymus athericus in European salt marshesMOLECULAR ECOLOGY, Issue 2 2003A.-C. Bockelmann Abstract We investigated genetic differentiation among populations of the clonal grass Elymus athericus, a common salt-marsh species occurring along the Wadden Sea coast of Europe. While E. athericus traditionally occurs in the high salt marsh, it recently also invaded lower parts of the marsh. In one of the first analyses of the genetic population structure in salt-marsh species, we were interested in population differentiation through isolation-by-distance, and among strongly divergent habitats (low and high marsh) in this wind- and water-dispersed species. High and low marsh habitats were sampled at six sites throughout the Wadden Sea. Based on reciprocal transplantation experiments conducted earlier revealing lower survival of foreign genotypes we predicted reduced gene flow among habitats. Accordingly, an analysis with polymorphic cross-species microsatellite primers revealed significant genetic differentiation between high and low marsh habitats already on a very small scale (< 100 m), while isolation-by-distance was present only on larger scales (60,443 km). In an analysis of molecular variance we found that 14% of the genetic variance could be explained by the differentiation between habitats, as compared to only 8.9% to geographical (isolation-by-distance) effects among six sites 2.5,443 km distant from each other. This suggests that markedly different selection regimes between these habitats, in particular intraspecific competition and herbivory, result in habitat adaptation and restricted gene flow over distances as small as 80 m. Hence, the genetic population structure of plant species can only be understood when considering geographical and selection-mediated restrictions to gene flow simultaneously. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||