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Middle Section (middle + section)
Selected AbstractsFlume experiments on the horizontal stream offset by strike-slip faultsEARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2004Shunji OuchiArticle first published online: 4 FEB 200 Abstract Flume experiments, in which the middle section of an erosion channel is displaced horizontally, have been conducted to assess the response of streams to horizontal displacement by a strike-slip fault. The experimental erosion channel was developed in a mixture of sand and clay, which provided relatively stable banks with its cohesiveness. Horizontal displacement of a strike-slip fault perpendicular to the channel is expected to add a ,at section to its longitudinal pro,le along the fault line. The experimental stream eliminated this ,at section with downstream degradation, upstream aggradation, and lateral channel shift. As a result, a roughly continuous longitudinal pro,le was maintained. This maintenance of a continuous longitudinal pro,le along channel is considered to be the principle of stream response to horizontal displacement by a strike-slip fault. Downstream degradation was the dominant process of this stream response in the overall tendency of erosion without sand supply. When the rate of fault displacement was low (long recurrence interval), the experimental stream eroded the fault surface, jutting laterally into the channel like a scarp, and de,ected the channel within the recurrence interval. This lateral channel shift gave some gradient to the reach created by fault displacement (offset reach), and the downstream degradation occurred as much as completing the remaining longitudinal pro,le adjustment. When the rate of fault displacement was high (short recurrence interval), the lateral erosion on the ,rst fault surface was interrupted by the next fault displacement. The displacement was then added incrementally to the existing channel offset making channel shift by lateral erosion increasingly dif,cult. The channel offset with sharp bends persisted without much modi,cation, and downstream degradation and upstream aggradation became evident with the effect of the offset channel course, which worked like a dam. In this case, a slight local convexity, which was incidentally formed by downstream degradation and upstream aggradation, tended to remain in the roughly continuous longitudinal pro,le, as long as the horizontal channel offset persisted. In either case, once the experimental stream obtained a roughly continuous gradient, further channel adjustment seemed to halt. Horizontal channel offset remained to a greater or lesser extent at the end of each run long after the last fault displacement. Copyright © 2004 John Wiley & Sons, Ltd. [source] Insect silk contains both a Kunitz-type and a unique Kazal-type proteinase inhibitorFEBS JOURNAL, Issue 7 2001Xavier Nirmala Insect silk is made up of structural fibrous (fibroins) and sticky (sericins) proteins, and contains a few small peptides of hitherto unknown functions. We demonstrate that two of these peptides inhibit bacterial and fungal proteinases (subtilisin, proteinase K and pronase). These ,silk proteinase inhibitors' 1 and 2 (SPI 1 and 2) are produced in the middle section of the silk-secreting glands prior to cocoon spinning and their production is controlled at transcription level. The full length cDNA of pre-SPI 1 contains 443 nucleotides and encodes a peptide of 76 amino-acid residues, of which 20 make up a signal sequence. The mature SPI 1 (6056.7 Da, 56 residues) is a typical thermostable Kunitz-type proteinase inhibitor with Arg in P1 position. The cDNA of pre-SPI 2 consists of 260 nucleotides and yields a putative secretory peptide of 58 amino-acid residues. The functional SPI 2 (3993 Da, 36 residues) is a single-domain Kazal-type proteinase inhibitor with unique structural features: free segment of the N-terminus is reduced to a single amino-acid residue, lack of CysI and CysV precludes formation of the A-ring and provides increased flexibility to the C-ring, and absence of several residues around the normal position of CysV shortens and changes the , helix segment of the protein. The structure reveals that the length and arrangement of the B-ring, including exposure of the P1 residue, and the position of the C-terminus relative to the B-loop, are essential for the activity of the Kazal-type inhibitors. [source] Cover Picture: Geomechanik und Tunnelbau 2/2008GEOMECHANICS AND TUNNELLING, Issue 2 2008Article first published online: 15 APR 200 The cover picture shows barrier rows built in 2007 as part of precautionary measures carried out in the middle section of the Kurtaschenbach in Cortaccia, South Tyrol (see page 139 ff). [source] The role of waves in ice-jam flooding of the Peace-Athabasca DeltaHYDROLOGICAL PROCESSES, Issue 19 2007Spyros Beltaos Abstract Since the late 1960s, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life in the Peace-Athabasca Delta (PAD) region. To identify the causes of this trend, and to develop mitigation or adaptation strategies under present and future climatic conditions, it is necessary to understand the mechanisms that lead to breakup of the ice cover and jamming within the delta reach of Peace River. Because the lower Peace is extremely flat, the long-period waves caused by spring snowmelt are not generally capable of dislodging the winter ice cover, even under conditions of very high flow. The ice cover decays in place and rubble generation, an essential condition for ice jamming, does not occur. However, major jams do, on occasion, form in the middle section of the river and make their way to the delta via repeated releases and stalls. Each release generates a steep wave which can greatly amplify the hydrodynamic forces that are applied on the ice cover and bring about its dislodgment. This is quantified for the lower Peace River by applying recently developed methodology to local hydrometric data. Detailed in situ observations in the spring of 2003, and additional data from 1997 and 2002, fully corroborate this conclusion. Implications to other flat rivers of northern Canada are discussed. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source] Role of habitat degradation in determining fish distribution and abundance along the lowland Warta River, PolandJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007A. Kruk Summary The distribution and abundance of fish collected in 1996,1998 are compared in three river sections X, Y and Z in the 808-km-long Warta River, Poland. The upper section, X, was least human-modified, the middle section, Y, was the most polluted by industry and regulated, and the downstream section, Z, was moderately disturbed. The differences between X and Y in concentrations of dissolved oxygen, volatile phenols and nitrite nitrogen, and in the index of availability of hiding places, were highly significant because these parameters were several times worse in the Y section; in the Z section they assumed intermediate values. Although the abundance of certain fish species was changing along the downstream river gradient (i.e. differed the most between X and Z), both the Kohonen artificial neural network (SOM) and assemblage indices showed the biggest differences between X and Y, thus confirming the crucial role of the degradation of aquatic environment in shaping fish assemblages. The latter result ensued from the reaction of the rheophilic burbot, stone loach, gudgeon, chub and dace, which were most abundant in X, almost absent in Y and reoccurring in Z (although less numerous when compared with X). The opposite was recorded for mud loach, tench, ide and silver bream, which were most abundant in the degraded section Y, probably because of weak competition with the almost-absent rheophils. The abundance of two generalists, roach and pike, was similar in all three sections, i.e. changed neither along the downstream nor in the degradation gradient. [source] Olfactory cues and nest recognition in the solitary bee Osmia lignariaPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2006Christelle Guédot Abstract., The use of olfactory cues for nest recognition by the solitary bee Osmia lignaria is studied in a greenhouse environment. Glass tubes are provided as nesting cavities to allow the in-nest behaviour of bees to be observed. In addition, each glass tube is cut into three sections for experimental manipulation and for subsequent chemical analysis. Nesting females drag their abdomen along the tube before exiting, spiral inside the tube, and sometimes deposit fluid droplets from the tip of the abdomen. For the manipulation, the outer section, the middle section, or both sections are removed and replaced with similar clean glass tube sections, and the behaviour exhibited by test females is recorded upon arrival in front of the nesting site and inside the nesting tubes. The resulting hesitation behaviour displayed by females after treatments appears to indicate the loss of some olfactory cues used for nest recognition inside the entire nest. Chemical analysis of the depositions inside the nesting tube, as well as analysis of the cuticular lipids of the nesting bees, reveals the presence of free fatty acids, hydrocarbons and wax esters. [source] Berry infection and the development of bunch rot in grapes caused by Aspergillus carbonariusPLANT PATHOLOGY, Issue 2 2008B. A. Kazi The effects of different levels of inoculum of Aspergillus carbonarius and time of inoculation on berry infection and the development of aspergillus bunch rot on grapevines (cv. Sultana) were studied under field conditions. Inflorescences at full bloom were inoculated with aqueous spore suspensions of A. carbonarius containing 0 or 1 × 106 spores mL,1 in 2004/05 and 0, 1 × 102 or 1 × 105 spores mL,1 in 2005/06. In both years, the incidence of infection in inoculated berries was significantly higher than in uninoculated berries. Incidence of infection in berries from veraison until harvest was higher than at earlier stages of bunch development (berry set to berries that were still hard and green). Inoculation of bunches at veraison did not significantly increase A. carbonarius infection prior to harvest, at harvest, 6 days after harvest or when berries were over-ripe. Bunches inoculated at harvest did not significantly increase infection 6 days after harvest or when berries were over-ripe. Aspergillus carbonarius was isolated more frequently from the pedicel end (53·1%) than from the middle section (37·5%) and distal end (35·0%) of berries that were inoculated with 105 spores mL,1. [source] Carbonatitic Volcanic Genesis of Hetaoqing Fe-Cu Deposit in Central Yunnan, ChinaRESOURCE GEOLOGY, Issue 4 2003Yongbei Zhang Abstract. The Kunyang rift on western margin of Yangtze Platform is a continental rift, and also a rare Precambrian Fe-Cu mineralization zone in China. The Wuding-Lufeng mineralization area in the middle section of the rift is an important part of the zone, and an elliptic-shaped volcanic collapsed basin, controlled by a ring fracture system with carbonatitic volcanic rocks mainly occurring along the northwestern edge of the basin. The Hetaoqing Fe-Cu ore deposit at the western side of the basin is hosted in carbonatitic volcanic rocks and pyroclastic sedimentary rocks. The original ore bodies occur as layers, bands and lenses conformable to the host carbonatitic rocks. The ores usually appear as massive, impregnated and granular in carbonatitic rocks, and as brecciform and sandy in pyroclastic sedimentary rocks. Ore-forming minerals are magnetite, hematite, chalcopy-rite, bornite, pyrite, carrollite, molybdenite, cobaltite and skinnerite, and secondary minerals limonite, chalcocite, azurite, malachite and tenorite. Gangue minerals are calcite, dolomite, ankerite, common hornblende, arfvedsonite, augite, aegirine-augite, albite, phlogopite, biotite, chlorite and apatite. Evidences of mineral chemistry, trace elements and isotopic ratios of ores, as well as geological features, suggest that the original ores are igneous in origin. Chemical features of magnetites in the deposit belong to carbonatite type, and are similar to those from the Bayan Obo carbonatites. The ores are rich in iron, titanium, rare earth elements, niobium, tantalum, gold, silver, phosphor and sulfur. These features indicate that the Fe-Cu deposit associated with volcanic activity in the Wuding-Lufeng basin is alkali-carbonatite volcanic type. [source] Comparison of root canal preparation using RaCe and ProTaper rotary Ni-Ti instrumentsINTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2005F. Paqué Abstract Aim, To compare various parameters of root canal preparation using RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium (Ni-Ti) instruments. Methodology, Fifty extracted mandibular molars with mesial root canal curvatures between 20° and 40° were embedded in a muffle system. All root canals were prepared to size 30 using RaCe or ProTaper rotary instruments in low-torque motors with torque control and constant speed of 300 r.p.m. (ProTaper with ATR Tecnika, Advanced Technology Research, Pistoia, Italy; RaCe with EndoStepper, S.E.T., Olching, Germany). In both groups irrigation was performed with 2 mL NaOCl (3%) after each instrument size. Calcinase-Slide (lege artis, Dettenhausen, Germany) was used as a chelating agent with each instrument. The following parameters were evaluated: straightening of curved root canals, postoperative root canal cross-sections, safety issues and working time. Cleanliness of the root canal walls was investigated under the SEM using 5-score indices for debris and smear layer. Statistical analysis was performed using the following tests: Wilcoxon's test for straightening and working time was used (P < 0.05); Fisher's exact test for comparison of cross-sections and root canal cleanliness (P < 0.05). Results, Both Ni-Ti systems maintained curvature well; the mean degree of straightening was less than 1° for both systems. Following preparation with RaCe, 49% of the root canals had a round or oval diameter and 50% an irregular diameter, ProTaper preparations resulted in a round or oval diameter in 50% of the cases. For debris, RaCe and ProTaper achieved 47 and 49% scores of 1 and 2, respectively; there was no significant difference. For smear layer, RaCe and ProTaper achieved 51 and 33% scores 1 and 2, respectively; no statistically significant differences were apparent for the coronal and middle sections of the root canals, but RaCe performed significantly better in the apical region (Fisher's exact test, P = 0.0392). Two roots lost working length with RaCe instruments, whilst ProTaper preparation resulted in two roots loosing working length and one fractured instrument. Mean working time was shorter for ProTaper (90.9 s) than for RaCe (137.6 s); the difference was significant (Wilcoxon's test, P = 0.011). Conclusions, Both systems respected original root canal curvature well and were safe to use. Cleanliness was not satisfactory for both systems. [source] A spatial queuing approach to optimize coordinated signal settings to obviate gridlock in adjacent work zonesJOURNAL OF ADVANCED TRANSPORTATION, Issue 4 2010C.K. Wong Abstract Gridlock is defined when traffic comes to a complete halt inducing huge delays. If a work zone on a two-lane two-way highway is set up, in which one of the traffic lanes is closed for maintenance road works, the remaining lane has to be controlled to serve the two-way traffic alternatively. The study objective is to optimize the traffic signal controls across two closely spaced work zones to prevent a gridlock, which can occur easily if upstream and downstream signals are not well coordinated. When vehicle queues build up in the middle sections between two work zones and further expand to occupy the single available lanes in both directions, the two-way traffic is then blocked and no vehicle can leave from the queues generating a gridlock. To address this problem, spatial queues are important parameters that must be explicitly analyzed. The cell transmission model, which is known to be a robust mathematical tool for the modeling of queue dynamics, is adopted in this study. A signal cell is used to represent each traffic signal control, the exit flow capacity of which is defined in accordance with the signal plan. A set of linear constraints is established to relate all of the model parameters and variables. The objective function is taken as the total number of vehicles in the critical section between the two work zones. The minimization of this objective function can effectively obviate the occurrence of a gridlock. The optimization problem is formulated as a Binary-Mixed-Integer-Linear-Program that can be solved by the standard branch-and-bound technique. Numerical examples are given to demonstrate the effectiveness of the proposed methodology. Copyright © 2010 John Wiley & Sons, Ltd. [source] Preventing crown collisions increases the crown cover and leaf area of maturing lodgepole pineJOURNAL OF ECOLOGY, Issue 3 2006SHAWN X. MENG Summary 1Crown collisions induced by tree sway are hypothesized to reduce crown closure and leaf area in maturing cold temperate forests. These declines are thought to lead to the decline in productivity when a stand ages. 2We tethered groups of lodgepole pine (Pinus contorta Dougl. Ex Loud. Var. latifolia Engelm.) trees in a web pattern at 10 m height, in four 15-m tall stands in western Alberta, Canada, to determine whether preventing crown collisions would increase crown cover and leaf area. 3The stands all had less than 65% crown closure at the beginning of study. Photographs of the canopy were taken in each control and webbed plot in 1998 and at the same point in 2004. Six years after webbing, crown cover had increased by 14.4%, compared to a 2.1% increase for the control plots. 4Webbing also resulted in significant increases in mean branch length, leaf area per branch and foliage density of individual branches from top and middle sections of the crown. Polishing of branches, caused by chronic contact with adjacent trees, was three times as common on control trees compared to webbed trees. The mean leaf area per tree was larger for the webbed trees. 5Crowns of webbed trees were more symmetrical than those of control trees. Trees from webbed plots, however, had a decline in leaf area density. The branches of control trees were typically curved upward with twigs pointed inward, making the crowns more compact compared to the outwardly expanding crowns of trees from the webbed plots. 6The fact that crowns expanded laterally after webbing, despite little change in light regime, provides strong evidence against the hypothesis that loss of crown closure in maturing stands is caused by a lack of light. 7The study indicates that the decline in crown closure and leaf area in maturing and tall stands is at least partly related to wind-induced sway of trees abrading the edges of crowns. [source] Distribution of several microorganisms and activity of alkaline phosphatase in sediments from Baihua LakeASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Jia-jun Deng Abstract The distribution characteristics of ammonifiers, ammonium-oxidizing bacteria, nitrite-oxidizing bacteria, and denitrifiers, and activities of alkaline phosphatase (ALP) in sediments from Baihua Lake (a man-made deep plateau canyon reservoir in Guizhou Province, China) were studied. The results suggested that the population number of ammonifiers in the sediments was higher at sampling sites Pingpu, Laojiutu, Yapengzhai, and Jiangjiapu than at the other sites. Ammonium-oxidizing bacteria had the highest population number at sampling site Meituwan. The population number of nitrite-oxidizing bacteria in the upper and middle sections of the lake was higher than that in the lower section. The population of denitrifiers was the highest at sampling site Jiangjiapu, and all the other sampling sites gave lower population numbers. Change in the activity of ALP was of a strong regularity, and the basic tendency was that the activity increased from the upper to the lower portion of the lake. Specifically, the activity at sampling site Yapengzhai was the strongest. The statistical analysis for four groups of bacteria, ALP, organic matter, and so on were carried out to shed more light on their correlativity. This research will likely provide relevant data useful for establishment of bacteriological and zymological indicator systems for environmental monitoring. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | |||||||||||||||||||