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Distinct Zones (distinct + zone)
Selected AbstractsShifting altitudinal distribution of outbreak zones of winter moth Operophtera brumata in sub-arctic birch forest: a response to recent climate warming?ECOGRAPHY, Issue 2 2007Snorre B. Hagen Climatic change is expected to affect the extent and severity of geometrid moth outbreaks, a major disturbance factor in sub-arctic birch forests. Previous studies have reported that the two geometrid species involved, autumnal moth and winter moth, differ in their temperature requirements and, consequently, in their altitudinal and latitudinal distribution patterns. In this study, we document the altitudinal distribution of winter moth outbreaks in a large coastal area in northern Norway. We show that, in the present winter moth outbreak, defoliated birch stands were seen as distinct zones with a rather constant width in the uppermost part of the forest and where the upper limit coincided with the forest line. The outbreak zone closely followed the spatially variable forest line as an undulating belt, although some of the variation in outbreak zone width was also related to variation in topographical variables, such as distance from the coast, forest line altitude, and slope of the terrain. A distinct outbreak zone at the altitudinal forest line is the typical picture that has been depicted in more qualitative historical records on previous outbreaks of autumnal moth rather than winter moth. We suggest that the recent documented climate warming in this region may have induced a shift in distribution of the winter moth both relative to topography and geography. Further investigation is, however, required to substantiate these suspicions. [source] Microbial communities in a porphyry copper tailings impoundment and their impact on the geochemical dynamics of the mine wasteENVIRONMENTAL MICROBIOLOGY, Issue 2 2007Nouhou Diaby Summary The distribution and diversity of acidophilic bacteria of a tailings impoundment at the La Andina copper mine, Chile, was examined. The tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) ,oxidation zone' characterized by low-pH (2.5,4), a ,neutralization zone' (70,80 to 300,400 cm) and an unaltered ,primary zone' below 400 cm. A combined cultivation-dependent and biomolecular approach (terminal restriction enzyme fragment length polymorphism and 16S rRNA clone library analysis) was used to characterize the indigenous prokaryotic communities in the mine tailings. Total cell counts showed that the microbial biomass was greatest in the top 125 cm of the tailings. The largest numbers of bacteria (109 g,1 dry weight of tailings) were found at the oxidation front (the junction between the oxidation and neutralization zones), where sulfide minerals and oxygen were both present. The dominant iron-/sulfur-oxidizing bacteria identified at the oxidation front included bacteria of the genus Leptospirillum (detected by molecular methods), and Gram-positive iron-oxidizing acidophiles related to Sulfobacillus (identified both by molecular and cultivation methods). Acidithiobacillus ferrooxidans was also detected, albeit in relatively small numbers. Heterotrophic acidophiles related to Acidobacterium capsulatum were found by molecular methods, while another Acidobacterium -like bacterium and an Acidiphilium sp. were isolated from oxidation zone samples. A conceptual model was developed, based on microbiological and geochemical data derived from the tailings, to account for the biogeochemical evolution of the Piuquenes tailings impoundment. [source] Microstructure Evolution and Mechanical Properties of Linear Friction Welded Ti-5Al-2Sn-2Zr-4Mo-4Cr (Ti17) Titanium Alloy Joints,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010Wen-Ya Li The microstructural evolution, microhardness, tensile properties and impact toughness of Ti-5Al-2Sn-2Zr-4Mo-4Cr (Ti17) alloy joints welded by linear friction welding (LFW) are investigated. A narrow, sound weld is formed, consisting of a superfine ,,+,, structure in the weld center. The structure gradually changes from the weld center to the parent Ti17 in the TMAZ, with the highly deformed , and , phases oriented along the deformation direction, owing to the uneven deformation and temperature distribution. The microhardness of the TMAZ is the lowest of the distinct zones and presents a valley-like shape. The tensile strengths of the joints are comparable to that of the parent Ti17 but with a much lower plasticity and impact toughness. The microstructure variation contributes to the resultant properties. [source] Spatial and temporal patterns of bone formation in ectopically pre-fabricated, autologous cell-based engineered bone flaps in rabbitsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2008Oliver Scheufler Abstract Biological substitutes for autologous bone flaps could be generated by combining flap pre-fabrication and bone tissue engineering concepts. Here, we investigated the pattern of neotissue formation within large pre-fabricated engineered bone flaps in rabbits. Bone marrow stromal cells from 12 New Zealand White rabbits were expanded and uniformly seeded in porous hydroxyapatite scaffolds (tapered cylinders, 10,20 mm diameter, 30 mm height) using a perfusion bioreactor. Autologous cell-scaffold constructs were wrapped in a panniculus carnosus flap, covered by a semipermeable membrane and ectopically implanted. Histological analysis, substantiated by magnetic resonance imaging (MRI) and micro-computerized tomography scans, indicated three distinct zones: an outer one, including bone tissue; a middle zone, formed by fibrous connective tissue; and a central zone, essentially necrotic. The depths of connective tissue and of bone ingrowth were consistent at different construct diameters and significantly increased from respectively 3.1 ± 0.7 mm and 1.0 ± 0.4 mm at 8 weeks to 3.7± 0.6 mm and 1.4 ± 0.6 mm at 12 weeks. Bone formation was found at a maximum depth of 1.8 mm after 12 weeks. Our findings indicate the feasibility of ectopic pre-fabrication of large cell-based engineered bone flaps and prompt for the implementation of strategies to improve construct vascularization, in order to possibly accelerate bone formation towards the core of the grafts. [source] Prograde metamorphic sequence of REE minerals in pelitic rocks of the Central Alps: implications for allanite,monazite,xenotime phase relations from 250 to 610 °CJOURNAL OF METAMORPHIC GEOLOGY, Issue 5 2008E. JANOTS Abstract The distribution of REE minerals in metasedimentary rocks was investigated to gain insight into the stability of allanite, monazite and xenotime in metapelites. Samples were collected in the central Swiss Alps, along a well-established metamorphic field gradient that record conditions from very low grade metamorphism (250 °C) to the lower amphibolite facies (,600 °C). In the Alpine metapelites investigated, mass balance calculations show that LREE are mainly transferred between monazite and allanite during the course of prograde metamorphism. At very low grade metamorphism, detrital monazite grains (mostly Variscan in age) have two distinct populations in terms of LREE and MREE compositions. Newly formed monazite crystallized during low-grade metamorphism (<440 °C); these are enriched in La, but depleted in Th and Y, compared with inherited grains. Upon the appearance of chloritoid (,440,450 °C, thermometry based on chlorite,choritoid and carbonaceous material), monazite is consumed, and MREE and LREE are taken up preferentially in two distinct zones of allanite distinguishable by EMPA and X-ray mapping. Prior to garnet growth, allanite acquires two growth zones of clinozoisite: a first one rich in HREE + Y and a second one containing low REE contents. Following garnet growth, close to the chloritoid,out zone boundary (,556,580 °C, based on phase equilibrium calculations), allanite and its rims are partially to totally replaced by monazite and xenotime, both associated with plagioclase (± biotite ± staurolite ± kyanite ± quartz). In these samples, epidote relics are located in the matrix or as inclusions in garnet, and these preserve their characteristic chemical and textural growth zoning, indicating that they did not experience re-equilibration following their prograde formation. Hence, the partial breakdown of allanite to monazite offers the attractive possibility to obtain in situ ages, representing two distinct crystallization stages. In addition, the complex REE + Y and Th zoning pattern of allanite and monazite are essential monitors of crystallization conditions at relatively low metamorphic grade. [source] Game theoretic approach to multiobjective designs: Focus on inherent safetyAICHE JOURNAL, Issue 1 2006Anjana Meel Abstract A method for designing processes that are inherently safer,with the primary focus on disturbances having the potential for unbounded hazardous responses,is introduced. In cases where safety is not threatened (as in isothermal fermentation reactors), but product quality can rapidly degrade, this method provides designs that ensure high product quality (as in pharmaceutical processes). Using game theory, the method accounts for the trade-offs in profitability, controllability, safety and/or product quality, and flexibility. For nonlinear processes that are hard to control; that is, have an unstable and/or nonminimum-phase steady state, over a wide range of operating conditions, extended bifurcation diagrams are introduced. When a steady state is nonminimum phase, the process may exhibit inverse response. The steady states of processes are classified on the basis of instability and nonminimum-phase behavior to segregate the operating regimes into distinct zones. Locally optimal designs, one corresponding to each zone, are obtained first. These are compared with other locally optimal designs at alternate operating conditions, and/or process reconfigurations, to obtain the globally optimal design using game theory. Four indices,profitability, controllability, safety and/or product quality, and flexibility,characterize the optimality of a design. A novel index for safe operation and/or product quality at a steady state is formulated as a function of the eigenvalues of the Jacobian of the process model and the Jacobian of the process zero dynamics, providing a quantitative measure of instability and nonminimum-phase behavior. The application of the proposed method to an isothermal, continuous stirred-tank reactor (CSTR) with van der Vusse reactions, an exothermic CSTR, and an anaerobic fermentor with substrate and product inhibition is presented. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Ultrasonographic examination of the adrenal gland and evaluation of the hypophyseal-adrenal axis in 20 catsJOURNAL OF SMALL ANIMAL PRACTICE, Issue 4 2000C. Zimmer The adrenal glands of 20 healthy, non-sedated cats were examined ultrasonographically; visualisation and assessment was possible in all cases. In comparison with the surrounding tissue, the adrenal glands were hypoecholc and two distinct zones could be differentiated In six of the cats. The length and width of the adrenal glands varied from 0.45 to 1.37 cm and 0.29 to 0.53 cm, respectively, and both dimensions could be reliably reproduced. The adrenal glands did not differ between male and female cats, and, in comparison to dogs, those of cats are more easily vlsualised ultrasonographically. The basal cortisol value ranged from 2.0 to 79 ,g/litre. Values 30 and 60 minutes after administration of ACTH (0.125 mg/cat intramuscularly) varied from 36 to 126 ,g/litre. The basal value of aldosterone ranged from 4 to 618 pg/ml. Values 30 and 60 minutes after administration of ACTH varied from 100 to 832 pg/ml. In all cats, suppression of the cortisol value below the level of detection (<2.0 pg/litre) occurred four and eight hours after the administration of dexamethasone (0.1 mg/kg intravenously). [source] Geothermal bryophyte habitats in the South Sandwich Islands, maritime AntarcticJOURNAL OF VEGETATION SCIENCE, Issue 4 2006P. Convey Ochyraet al. (in press) for mosses, Bednarek-Ochyra et al. (2000) for liverworts, Øvstedal & Lewis Smith (2001) for lichens Abstract Question: How does geothermal activity influence terrestrial plant colonization, species composition and community development in the Antarctic? Location: South Sandwich Islands, maritime Antarctic. Methods: Bryophytes were documented during a biological survey of the archipelago in January and February 1997. Particular attention was given to sites under current or recent influence of geothermal activity. Temperature profiles obtained across defined areas of activity on several islands were linked with the presence of specific bryophytes. Results: Greatest bryophyte richness was associated with geothermally influenced ground. Of 35 moss and nine liverwort species recorded, only four mosses were never associated with heated ground, while eight of the liverworts and 50% of the mosses were found only on actively or recently heated ground. Some species occur in unheated sites elsewhere in the maritime Antarctic, but were absent from such habitats on the South Sandwich Islands. Several species occurred in distinct zones around fumaroles. Maximum temperatures recorded within the upper 0.5 cm of the vegetation surface were 40 - 47 °C, with only Campylopus introflexus tolerating such temperatures. Maximum temperatures 2.5 or 5 cm below the vegetation surface of this moss reached 75 °C. Other bryophytes regularly present in zoned vegetation included the mosses Dicranella hookeri, Sanionia georgico-uncinata, Pohlia nutans and Notoligotrichum trichodon, and the liverworts Cryptochila grandiflora and Marchantia berteroana. Surface temperatures of 25 - 35 °C and subsurface temperatures of 50 - 60 °C were recorded in these species. Conclusions: These exceptional plant communities illustrate the transport of viable propagules into the Antarctic. Individually ephemeral in nature, the longer term existence of geothermal habitats on islands along the Scotia Arc may have provided refugia during periods of glacial expansion, facilitating subsequent recolonization of Antarctic terrestrial habitats. [source] Identification, isolation, and RT-PCR analysis of single stage-specific spermatogenetic cells obtained from portions of seminiferous tubules classified by transillumination microscopyMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 12 2009Chiara Vasco The protocol here described allows the analysis of gene expression in single specific mouse spermatogenetic cells. Germ cells were singularly isolated by microdissection of portions of seminiferous tubules classified, based on their transillumination pattern, into four distinct zones along their length. Single portions of a seminiferous tubule, corresponding to specific zones, were mechanically disaggregated into single cells that were (1) identified as spermatogonia, spermatocytes, round or elongated spermatids, (2) isolated using a micromanipulator, and (3) singularly transferred into a test tube for retro-transcription PCR analysis. On each single isolated cell, we have determined the quantitative profile of expression of Gapdh, an endogenous housekeeping gene known to be expressed throughout spermatogenesis. The protocol described allows an accurate analysis of the temporal and quantitative profile of gene expression throughout the whole male gamete differentiation process which so far has mainly been performed on enriched population of cells. Mol. Reprod. Dev. 76: 1173,1177, 2009. © 2009 Wiley-Liss, Inc. [source] Subzonal organization of olfactory sensory neurons projecting to distinct glomeruli within the mouse olfactory bulbTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2003Olga Levai Abstract Olfactory sensory neurons located in the nasal neuroepithelium send their axons directly into the olfactory bulb, where they contact the dendrites of second-order neurons in specialized spherical structures called glomeruli; each sensory neuron projects to a single glomerulus. All neurons expressing the same odorant receptor gene are confined to distinct zones within the epithelium and converge their axons onto a small number of common glomeruli. In the present study, we analyzed transgenic mouse lines in which the projection of a neuron population expressing a particular receptor gene can be visualized as a result of axonal markers that are coexpressed. The target glomeruli could thus reproducibly be identified and allowed to deposit retrograde tracers precisely. After an appropriate incubation time, olfactory sensory neurons within distinct areas of the olfactory epithelium were labeled. The two subpopulations of neurons retrogradely stained by differently colored fluorescent dyes deposited at the dorsal and the dorsomedial glomerulus, respectively, were found to be segregated within distinct areas of the expression zone, where the cells expressing the same receptor type displayed a stochastic distribution. J. Comp. Neurol. 458:209,220, 2003. © 2003 Wiley-Liss, Inc. [source] Geophysical investigation of the site of the former monastic settlement, Clonard, County Meath, IrelandARCHAEOLOGICAL PROSPECTION, Issue 1 2006Paul J. Gibson Abstract Clonard, in County Meath, Ireland was a major ecclesiastical centre from the early sixth century to the twelfth century and buildings associated with the monastery were in existence until the late eighteenth century. However, today no extant buildings or features associated with the monastery are known. The geophysical investigation undertaken in this project has uncovered many anomalies which may be related to the monastic settlement at Clonard. A significant number of linear anomalies have been detected east of St Finian's church using magnetic gradiometry and twin electrode resistance surveying. Many of these anomalies are probably field boundaries; however, a much greater diversity of geophysical responses is located south and west of St Finian's church. A subsquare enclosure of 60,m sides is adjacent to a 300,m long palaeochannel. A fine network of intersecting low resistance anomalies probably represent former artificial drainage channels. Three large areas associated with anomalous magnetic readings were located which might indicate sites of human activity. In addition, there are four distinct zones which have large concentrations of high resistance values suggesting the presence of walls or buildings. Resistivity and ground-penetrating radar depth slices show that one of these zones has characteristics which indicate the presence of an east,west aligned building approximately 7,m wide in a north,south direction and about 15,m long in an east,west direction. Copyright © 2005 John Wiley & Sons, Ltd. [source] Response of an open-forest ant community to invasion by the introduced ant, Pheidole megacephalaAUSTRAL ECOLOGY, Issue 3 2000C. Vanderwoude Abstract The introduced tramp ant, Pheidole megacephala, is a well-known pest of urban areas and coastal dune ecosystems in eastern Australia. Until recently, establishment and spread of P. megacephala colonies has been regarded as likely only in disturbed areas. Here we describe the extent of an established colony of P. megacephala in a long undisturbed open forest near Maryborough in southeast Queensland and compare ant community structure with those of nearby uninfested sites. Tuna baiting revealed three distinct zones: (i) a zone totally dominated by P. megacephala (at least 10 ha) where few other ant ant species were detected; (ii) a zone where P. megacephala was absent and many other ant species were found; and (iii) a zone where opportunists (species of Ochetellus and Paratrechina) competed with P. megacephala at baits. Pitfall trapping over a 9-month period resulted in 12 species being recorded at the infested site, compared with a mean of 25 species recorded at adjoining uninfested forest. Over 94% of ants recorded in pitfalls at the infested site were P. megacephala. Most notably, P. megacephala had completely displaced dominant Dolichoderines (species of Iridomyrmex), subordinate Camponotini (species of Camponotus, Opisthopsis and Polyrhachis) and other species of Pheidole which are common at forest sites. [source] 2431: The eyelid margin: an underestimated contributor to ocular surface health and diseaseACTA OPHTHALMOLOGICA, Issue 2010E KNOP Purpose The eyelid margin is frequently underestimated in the consideration of factors in ocular surface health and disease. Clinically the whole free end of the lid margin is often addressed simply as "margin" without further differentiation. It is attempted to review the structure, embryology and function of the lid margin as well as its involvement in ocular surface pathology. Methods A review based on the available literature on the lid margin is prepared together with own findings on the histology of normal and pathological tissues. Results The human lid margin is divided into distinct zones that consist, coming from the skin side, of a rounded outer lid border, a free lid margin (between the eye lashes and the opening of the meibomian glands), the muco-cutaneous junction and a sharp inner lid border. The embryological development of the eye lids and their tissue components (loose connective tissue, lid muscles, ciliary hairs, Meibomian glands and vascular and neural components) takes place during the period of sealed lids. During this time the development of the Meibomian glands shows considerable similarity to that of the ciliary hairs. The sealing of the mesodermal lid folds and their eventual separation is dependent on several factors that may be involved in pathology. Various disease states, as well as the aging process, can lead to destruction of the lid margin and, conversely, this can lead to deterioration of the cornea and conjunctiva. Conclusion The eyelid margin is an underestimated contributor to ocular surface health and disease. Increased awareness of the anatomy, embryology, physiology and pathophysiology of the lid margin and it tissue components appears important for the preservation of ocular surface integrity. Support DFG KN317/11 [source] | ||||||||||||||||