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M Long (m + long)
Selected AbstractsWood storage in a wide mountain river: case study of the Czarny Dunajec, Polish CarpathiansEARTH SURFACE PROCESSES AND LANDFORMS, Issue 12 2005omiej Wy Abstract Storage of large woody debris in the wide, mountain, Czarny Dunajec River, southern Poland, was investigated following two floods of June and July 2001 with a seven-year frequency. Within a reach, to which wood was delivered only by bank erosion and transport from upstream, wood quantities were estimated for eighty-nine, 100 m long, channel segments grouped into nine sections of similar morphology. Results from regression analysis indicated the quantity of stored wood to be directly related to the length of eroded, wooded banks and river width, and inversely related to unit stream power at the flood peak. The largest quantities of wood (up to 33 t ha,1) were stored in wide, multi-thread river sections. Here, the relatively low transporting ability of the river facilitated deposition of transported wood while a considerable length of eroded channel and island banks resulted in a large number of trees delivered from the local riparian forest. In these sections, a few morphological and ecological situations led to the accumulation of especially large quantities of wood within a small river area. Very low amounts of wood were stored in narrow, single-thread sections of regulated or bedrock channel. High stream power facilitated transport of wood through these sections while the high strength of the banks and low channel sinuosity prevented bank retreat and delivery of trees to the channel. Considerable differences in the character of deposited wood existed between wide, multi-thread channel sections located at different distances below a narrow, 7 km long, channellized reach of the river. Wood deposited close to the downstream end of the channellized reach was highly disintegrated and structured into jams, whereas further downstream well preserved shrubs and trees prevailed. This apparently reflects differences in the distance of wood transport and shows that in a mountain river wider than the height of trees growing on its banks, wood can be transported long distances along relatively narrow, single-thread reaches but is preferentially deposited in wide, multi-thread reaches. Copyright © 2005 John Wiley & Sons, Ltd. [source] Controlling factors of gullying in the Maracujá Catchment, southeastern BrazilEARTH SURFACE PROCESSES AND LANDFORMS, Issue 11 2005L. de A. P. Bacellar Abstract Hundreds of gullies (,voçorocas') of huge dimensions (up to 400,500 m long, 150 m wide and 50 m deep) are very common in the small Maracujá Catchment in southeastern Brazil. These erosional features, which occur with an uneven intensity throughout the area, started due to bad soil management practices at the beginning of European settlement, at the end of the 17th century, and nowadays are still evolving, but at a slower rate. As surface soils are usually very resistant to erosion, the outcrop of the more erodible basement saprolites seems to be an essential condition for their beginning. An analysis of well known erosion controlling factors was performed, aiming to explain the beginning and evolution of these gullies and to understand the reasons for their spatial distribution. Data shows that geology and, mainly, geomorphology are the main controlling factors, since gullies tend to be concentrated in basement rock areas with lower relief (domain 2) of Maracujá Catchment, mainly at the fringes of broad and flat interfluves. At the detailed scale (1:10 000), gullies are more common in amphitheatre-like headwater hollows that frequently represent upper Quaternary gullies (paleogullies), which demonstrate the recurrence of channel erosion. So, gullies occur in areas of thicker saprolites (domain 2), in places with a natural concentration of surface and underground water (hollows). Saprolites of the preserved, non-eroded hollows are usually pressurized (confined aquifer) due to a thick seal of Quaternary clay layer, in a similar configuration to the ones found in hollows of mass movement (mudflow) sites in southeastern Brazil. Therefore, the erosion of the resistant soils by human activities, such as road cuts and trenches (,valos'), or their mobilization by mudflow movements, seem to be likely mechanisms of gullying initiation. Afterwards, gullies evolve by a combination of surface and underground processes, such as wash and tunnel erosion and falls and slumps of gully walls. Copyright © 2005 John Wiley & Sons, Ltd. [source] Cyclic behavior of laterally loaded concrete piles embedded into cohesive soilEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 1 2008Rabin Tuladhar Abstract Modern seismic design codes stipulate that the response analysis should be conducted by considering the complete structural system including superstructure, foundation, and ground. However, for the development of seismic response analysis method for a complete structural system, it is first imperative to clarify the behavior of the soil and piles during earthquakes. In this study, full-scale monotonic and reversed cyclic lateral loading tests were carried out on concrete piles embedded into the ground. The test piles were hollow, precast, prestressed concrete piles with an outer diameter of 300,mm and a thickness of 60,mm. The test piles were 26,m long. Three-dimensional (3D) finite element analysis was then performed to study the behavior of the experimental specimens analytically. The study revealed that the lateral load-carrying capacity of the piles degrades when subjected to cyclic loading compared with monotonic loading. The effect of the use of an interface element between the soil and pile surface in the analysis was also investigated. With proper consideration of the constitutive models of soil and pile, an interface element between the pile surface and the soil, and the degradation of soil stiffness under cyclic loading, a 3D analysis was found to simulate well the actual behavior of pile and soil. Copyright © 2007 John Wiley & Sons, Ltd. [source] The artisanal fishery fleet of the lower AmazonFISHERIES MANAGEMENT & ECOLOGY, Issue 3 2008V. J. ISAAC Abstract, The present study analyses temporal trends in the characteristics of the artisanal fleet landing at ports in the city of Santarém (lower Amazon) from 1993 to 2003. A total of 2714 boats visited the city, accounting for more than 76 000 landings. Of these, 1952 were fishing boats; the others were buyer boats, specialised in the purchase of fish in rural areas for resale in Santarém. The activity involves more than 13 000 fishermen. Fishing boats are made of wood, are on average 11 m long and powered by a 20 hp outboard motor. Boats operate with an average of six to seven fishermen, spending 6 days per trip and catching between 300 and 800 kg of fish. Most variability in yield can be explained by the ice consumed (70%), the number of fishermen trip,1 (19%), fuel consumed (4%) and days spent fishing (3%). The yield changed according to the size, origin and type of boat. Fishing boats coming from more distant locations, in the state of Amazonas, performed better than those from Santarém. Total yield declined slightly during the study period. Mean age of fishing boats and fishing power is increasing. Consumption of ice and fuel by trip, number of fishermen trip,1 and mean days fishing showed positive trends. Financial subsidies from governmental agencies are criticised. Fleet performance and management options are discussed. [source] The world's longest graptolite?GEOLOGICAL JOURNAL, Issue 1 2001David K. Loydell Abstract An incomplete specimen of Stimulograptus halli 1.45,m long is recorded from the Aberystwyth Grits Formation north of Clarach, western mid-Wales. This is the longest graptoloid graptolite known. Assuming a growth rate similar to that of modern Rhabdopleura it lived for at least 25 years. Copyright © 2001 John Wiley & Sons, Ltd. [source] First and second tube of the Tauern TunnelGEOMECHANICS AND TUNNELLING, Issue 4 2010Article first published online: 5 AUG 2010 After scarcely four years of construction work, the second Tauern Tunnel tube on the A10 was opened for traffic on the 30 April 2010. The 6, 400 m long mined tunnel was constructed in only 22 months by Porr Tunnelbau GmbH. The new valley tube of the Tauern Tunnel, with its seven stopping niches, 26 cross passages, full transverse ventilation, and the light, reflective coating on the tunnel walls, is among the most modern tunnels in Austria. Nach knapp vierjähriger Bauzeit wurde am 30. April 2010 die zweite Tauerntunnelröhre derA10 eröffnet und in Betrieb genommen. Der 6.400 m lange bergmännische Vortrieb wurde in nur 22 Monaten von der Porr Tunnelbau GmbH hergestellt. Die neue Talröhre des Tauerntunnels zählt mit seinen sieben Abstellnischen, 26 Querschläge, einer Vollquerlüftung und der hellen, reflektierenden Tunnelwandbeschichtung zu den modernsten Tunnel Österreichs. [source] Vegetation responses in Alaskan arctic tundra after 8 years of a summer warming and winter snow manipulation experimentGLOBAL CHANGE BIOLOGY, Issue 4 2005C.-H. A. Wahren Abstract We used snow fences and small (1 m2) open-topped fiberglass chambers (OTCs) to study the effects of changes in winter snow cover and summer air temperatures on arctic tundra. In 1994, two 60 m long, 2.8 m high snow fences, one in moist and the other in dry tundra, were erected at Toolik Lake, Alaska. OTCs paired with unwarmed plots, were placed along each experimental snow gradient and in control areas adjacent to the snowdrifts. After 8 years, the vegetation of the two sites, including that in control plots, had changed significantly. At both sites, the cover of shrubs, live vegetation, and litter, together with canopy height, had all increased, while lichen cover and diversity had decreased. At the moist site, bryophytes decreased in cover, while an increase in graminoids was almost entirely because of the response of the sedge Eriophorum vaginatum. These community changes were consistent with results found in studies of responses to warming and increased nutrient availability in the Arctic. However, during the time period of the experiment, summer temperature did not increase, but summer precipitation increased by 28%. The snow addition treatment affected species abundance, canopy height, and diversity, whereas the summer warming treatment had few measurable effects on vegetation. The interannual temperature fluctuation was considerably larger than the temperature increases within OTCs (<2°C), however. Snow addition also had a greater effect on microclimate by insulating vegetation from winter wind and temperature extremes, modifying winter soil temperatures, and increasing spring run-off. Most increases in shrub cover and canopy height occurred in the medium snow-depth zone (0.5,2 m) of the moist site, and the medium to deep snow-depth zone (2,3 m) of the dry site. At the moist tundra site, deciduous shrubs, particularly Betula nana, increased in cover, while evergreen shrubs decreased. These differential responses were likely because of the larger production to biomass ratio in deciduous shrubs, combined with their more flexible growth response under changing environmental conditions. At the dry site, where deciduous shrubs were a minor part of the vegetation, evergreen shrubs increased in both cover and canopy height. These changes in abundance of functional groups are expected to affect most ecological processes, particularly the rate of litter decomposition, nutrient cycling, and both soil carbon and nitrogen pools. Also, changes in canopy structure, associated with increases in shrub abundance, are expected to alter the summer energy balance by increasing net radiation and evapotranspiration, thus altering soil moisture regimes. [source] Net grassland carbon flux over a subambient to superambient CO2 gradientGLOBAL CHANGE BIOLOGY, Issue 7 2001P. C. Mielnick Abstract Increasing atmospheric CO2 concentrations may have a profound effect on the structure and function of plant communities. A previously grazed, central Texas grassland was exposed to a 200-µmol mol,1 to 550 µmol mol,1 CO2 gradient from March to mid-December in 1998 and 1999 using two, 60-m long, polyethylene- covered chambers built directly onto the site. One chamber was operated at subambient CO2 concentrations (200,360 µmol mol,1 daytime) and the other was regulated at superambient concentrations (360,550 µmol mol,1). Continuous CO2 gradients were maintained in each chamber by photosynthesis during the day and respiration at night. Net ecosystem CO2 flux and end-of-year biomass were measured in each of 10, 5-m long sections in each chamber. Net CO2 fluxes were maximal in late May (c. day 150) in 1998 and in late August in 1999 (c. day 240). In both years, fluxes were near zero and similar in both chambers at the beginning and end of the growing season. Average daily CO2 flux in 1998 was 13 g CO2 m,2 day,1 in the subambient chamber and 20 g CO2 m,2 day,1 in the superambient chamber; comparable averages were 15 and 26 g CO2 m,2 day,1 in 1999. Flux was positively and linearly correlated with end-of-year above-ground biomass but flux was not linearly correlated with CO2 concentration; a finding likely to be explained by inherent differences in vegetation. Because C3 plants were the dominant functional group, we adjusted average daily flux in each section by dividing the flux by the average percentage C3 cover. Adjusted fluxes were better correlated with CO2 concentration, although scatter remained. Our results indicate that after accounting for vegetation differences, CO2 flux increased linearly with CO2 concentration. This trend was more evident at subambient than superambient CO2 concentrations. [source] Hexagonal Network Organization of Dye-Loaded Zeolite,L Crystals by Surface-Tension Driven Autoassembly,ADVANCED FUNCTIONAL MATERIALS, Issue 17 2006S. Yunus Abstract Highly fluorescent dye-loaded zeolite,L crystals, approximately 1.4,,m long and 650,nm in diameter, are organized in a hexagonal network by a surface-tension-driven autoassembly process. A polydimethylsiloxane (PDMS) film presenting a trigonal ordering of spherical protuberances, including a polystyrene (PS) hexagonal network occupying their interstices, is chosen as the platform for the assembly. The overall wettability and the difference in surface tension between PDMS and PS surfaces are found to offer good conditions for ordering micrometric dye-loaded zeolite,L crystals in a 2D hexagonal network. The resulting film displays a regular hexagonal pattern of polarized fluorescence, reflecting the polarization properties of the dye molecules inserted in the parallel nanochannels of the zeolites. [source] Variability of shallow overland flow velocity and soil aggregate transport observed with digital videographyHYDROLOGICAL PROCESSES, Issue 20 2008A. Sidorchuk Abstract Field experiments at Tiramoana station 30 km north of Christchurch, New Zealand using an erosion plot 16·5 m long, 0·6 m wide, and with a slope of 14,14·5° on rendzina soil aimed to measure the variability of flow velocity and of soil aggregates transport rate in shallow overland flow. Discharge/cross-section area ratio was used to estimate mean velocity, and high-speed digital video camera and image analysis provided information about flow and sediment transport variability. Six flow runs with 0·5,3·0 L s,1 discharges were supercritical with Froude numbers close to or more than 1. Mean flow velocity followed Poiseuille law, float numbers were more than 1·5 and hydraulic resistance was an inverse proportional function of the Reynolds number, which is typical for laminar flows. Hence actual velocity varied through time significantly and the power spectrum was of ,red-noise', which is typical for turbulent flow. Sediment transport rates had even higher variability, and soil aggregates transport was a compound Poisson process. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simulating soil-water movement under a hedgerow surrounding a bottomland reveals the importance of transpiration in water balanceHYDROLOGICAL PROCESSES, Issue 5 2008Z. Thomas Abstract The objective of this study was to quantify components of the water balance related to root-water uptake in the soil below a hedgerow. At this local scale, a two-dimensional (2D) flow domain in the x,z plane 6 m long and 1·55 m deep was considered. An attempt was made to estimate transpiration using a simulation model. The SWMS-2D model was modified and used to simulate temporally and spatially heterogeneous boundary conditions. A function with a variable spatial distribution of root-water uptake was considered, and model calibration was performed by adjusting this root-water uptake distribution. Observed data from a previous field study were compared against model predictions. During the validation step, satisfactory agreement was obtained, as the difference between observed and modelled pressure head values was less than 50 cm for 80% of the study data. Hedge transpiration capacity is a significant component of soil-water balance in the summer, when predicted transpiration reaches about 5·6 mm day,1. One of the most important findings is that hedge transpiration is nearly twice that of a forest canopy. In addition, soil-water content is significantly different whether downslope or upslope depending on the root-water uptake. The high transpiration rate was mainly due to the presence of a shallow water table below the hedgerow trees. Soil-water content was not a limiting factor for transpiration in this context, as it could be in one with a much deeper water table. Hedgerow tree transpiration exerts a strong impact not only on water content within the vadose zone but also on the water-table profile along the transect. Results obtained at the local scale reveal that the global impact of hedges at the catchment scale has been underestimated in the past. Transpiration rate exerts a major influence on water balance at both the seasonal and annual scales for watersheds with a dense network of hedgerows. Copyright © 2007 John Wiley & Sons, Ltd. [source] Runoff and suspended sediment yields from an unpaved road segment, St John, US Virgin IslandsHYDROLOGICAL PROCESSES, Issue 1 2007Carlos E. Ramos-Scharrón Abstract Unpaved roads are believed to be the primary source of terrigenous sediments being delivered to marine ecosystems around the island of St John in the eastern Caribbean. The objectives of this study were to: (1) measure runoff and suspended sediment yields from a road segment; (2) develop and test two event-based runoff and sediment prediction models; and (3) compare the predicted sediment yields against measured values from an empirical road erosion model and from a sediment trap. The runoff models use the Green,Ampt infiltration equation to predict excess precipitation and then use either an empirically derived unit hydrograph or a kinematic wave to generate runoff hydrographs. Precipitation, runoff, and suspended sediment data were collected from a 230 m long, mostly unpaved road segment over an 8-month period. Only 3,5 mm of rainfall was sufficient to initiate runoff from the road surface. Both models simulated similar hydrographs. Model performance was poor for storms with less than 1 cm of rainfall, but improved for larger events. The largest source of error was the inability to predict initial infiltration rates. The two runoff models were coupled with empirical sediment rating curves, and the predicted sediment yields were approximately 0·11 kg per square meter of road surface per centimetre of precipitation. The sediment trap data indicated a road erosion rate of 0·27 kg m,2 cm,1. The difference in sediment production between these two methods can be attributed to the fact that the suspended sediment samples were predominantly sand and silt, whereas the sediment trap yielded mostly sand and gravel. The combination of these data sets yields a road surface erosion rate of 0·31 kg m,2 cm,1, or approximately 36 kg m,2 year,1. This is four orders of magnitude higher than the measured erosion rate from undisturbed hillslopes. The results confirm the importance of unpaved roads in altering runoff and erosion rates in a tropical setting, provide insights into the controlling processes, and provide guidance for predicting runoff and sediment yields at the road-segment scale. Copyright © 2006 John Wiley & Sons, Ltd. [source] Directions of preferential flow in a hillslope soil, 1.HYDROLOGICAL PROCESSES, Issue 4 2005Quasi-steady flow Abstract Preferred infiltration is mainly perceived as vertically down whereas subsurface storm flow is thought to occur parallel to slopes. The transition from vertical to lateral flow in a layered hillslope soil is the focus of the contribution. Transient flow is assumed to move as a wetting front. Three time-domain reflectometry (TDR) wave-guides, each 0·15 m long, were mounted in the shape of a truncated tetrahedron with its peak pointing down. Each wave-guide focuses the front velocity along its axis. The three front-velocity vectors are decomposed into their x, y and z components, which are then assembled to the resultant velocity vector. The volume density flux of preferred flow is the product of the front velocity and the mobile water content. The latter is the amplitude of transient soil moisture measured with each wave-guide. The resultant vector of the volume flux density is computed similarly to the velocity vector. The experimental approach allows for the rapid assessment of transient flows without relying on the variation of water potentials. The experiments indicate that the directions of the resultant vectors of velocity and volume flux density can be estimated if the moisture variations of the three TDR wave-guides are strongly correlated during the passing of the wetting front. Copyright © 2004 John Wiley & Sons, Ltd. [source] Validation of a vegetated filter strip model (VFSMOD)HYDROLOGICAL PROCESSES, Issue 5 2001Dr Majed Abu-Zreig Abstract Vegetated filter strips (VFS) are designed to reduce sediment load and other pollutants into water bodies. However, adaptation of VFS in the field has been limited owing to lack of data about their efficiency and performance under natural field conditions. A number of models are available that simulate sediment transport and trapping in VFS, but there is a general lack of confidence in VFS models owing to limited validation studies and model limitations that prevent correct application of these models under field conditions. The objective of this study is to test and validate a process-based model (VFSMOD) that simulates sediment trapping in VFS. This model links three submodels: modified Green,Ampt's infiltration, Quadratic overland flow submodel based on kinematic wave approximation and University of Kentucky sediment filtration model. A total of 20 VFS, 2, 5, 10 and 15 m long and with various vegetation covers, were tested under simulated sediment and runoff conditions. The results of these field experiments were used to validate the VFS model. The model requires 25 input parameters distributed over five input files. All input parameters were either measured or calculated using experimental data. The observed sediment trapping efficiencies varied from 65% in the 2-m long VFS to 92% in the 10-m long filters. No increase in sediment removal efficiency was observed at higher VFS length. Application of the VFS model to experimental data was satisfactory under the condition that actual flow widths are used in the model instead of the total filter width. Predicted and observed sediment trapping efficiencies and infiltration volume fitted very well, with a coefficient of determination (R2) of 0·9 and 0·95, respectively. Regression analyses revealed that the slope and intercept of the regression lines between predicted versus observed infiltration volume and trapping efficiency were not significantly different than the line of perfect agreement with a slope of 1·0 and intercept of 0·0. Copyright © 2001 John Wiley & Sons, Ltd. [source] Recent Activities of HTS Power Application in KoreaINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 3 2007Minwon Park From April 2007, DAPAS (Development of the Advanced Power system by Applied Superconductivity technologies), which is a 10-year-long program, entered the final phase with 4 years. For the last 7 years, the significant achievement of DAPAS is that a 10 m long and 100 A critical current-coated conductor and core technologies of distribution line voltage class HTS power systems including cables, transformers, fault current limiters (FCLs), and motors have been developed. In particular, a 100 m length HTS power cable was installed and is operating well in the Gochang power system test center. Two different types of FCL were successfully developed and demonstrated very good results of fault current test with 22.9 kV distribution line voltage class. In the case of the HTS motor, it was well operated too on connecting to 2 units of a 1.1 MVA conventional induction motor each as a load. In addition, the coated conductor project team achieved a 30 m length and 185 A critical current-coated conductor tape after 6 months since the hardware was set up. [source] The Tantura F Shipwreck, IsraelINTERNATIONAL JOURNAL OF NAUTICAL ARCHAEOLOGY, Issue 1 2007Ofra Barkai Tantura F is the first wreck excavated so far in the eastern Mediterranean dated to the beginning of the 8th century AD (the local early Islamic period), based on 14C and pottery analysis. Among the finds were the remains of about 30 ceramic vessels, two anchors, food remnants, fish-bones, a needle, a spoon and a glass vessel. Tantura F was c.15 m long and 5 m wide, and hull remains comprise keel, frames, planks, stringers, mast-step, and other internal components. Construction features clearly indicate frame-based construction, considerably earlier than it is generally thought to have been first employed. © 2006 The Authors [source] Disturbance facilitates rapid range expansion of aspen into higher elevations of the Rocky Mountains under a warming climateJOURNAL OF BIOGEOGRAPHY, Issue 1 2010Simon M. Landhäusser Abstract Aim, Trembling aspen (Populus tremuloides Michx.) is absent in the upper foothills region of west-central Alberta because of the cold conditions and short growing season at this high elevation. However, in recent years it appears that aspen has been establishing from seed in this zone and that it has been doing so mainly as a result of forest harvesting. The objectives of this study were to determine the frequency of and types of microsite required for the successful establishment of aspen seedlings at these higher elevations. Location, Rocky Mountains Upper Foothills Natural Subregion of west-central Alberta, Canada. Methods, The current distribution of mature aspen and the presence and absence of aspen seedlings in harvested areas were determined in an area c. 300 km2 in size, using ground and aerial surveys. In an intensive study, 12 belt transects (180 m long and 5 m wide) were established in areas disturbed by forest harvesting at high elevations where no aspen was present prior to harvesting. Transects were surveyed seven growing seasons after disturbance and the microsites occupied by aspen seedlings were characterized according to their substrate and microtopography. Similarly, the availability of different substrates and microtopographic positions were assessed by systematic point sampling on these sites. Results, On level surfaces, aspen seedling regeneration was found up to 200 m higher in elevation than the mature aspen in the original undisturbed forests. Overall, there were 428 seedlings ha,1 established on these transects, and the age distribution indicates that aspen seedlings had established in each of the seven growing seasons since the disturbance. Nearly all of the seedlings (93%) were established on mineral soil microsites and virtually no seedlings were established on undisturbed forest floor layers. Significantly more seedlings were found in concave microtopographic positions. Main conclusions, This study indicates that aspen establishment from seed is currently not a stochastic event and demonstrates that aspen is rapidly expanding its range upslope in the Canadian Rocky Mountain region as a result of forest management practices that expose mineral soil substrates in conjunction with a warming climate. The change in canopy composition from conifer to deciduous forests at these higher elevations will have far-reaching implications for ecosystem processes and functions. [source] Bat species diversity and distribution in three vegetation communities of Meru National Park, KenyaAFRICAN JOURNAL OF ECOLOGY, Issue 3 2004Paul W. Webala Abstract Diversity and distribution of bats was determined in four vegetation types in and around Meru National Park, Kenya between September 2000 and February 2001. Bat-habitat studies were based on plant species dominance, cover and farming activities. Bats were captured using standard mist nets (18 m long × 2 m high) erected on poles averaging 3 m. Vegetation was broadly grouped as Acacia or Combretum wooded grassland, or Acacia,Commiphora bushland and studied using the Braun-Blanquet method. Analysis of floristic similarity showed five vegetation species assemblages in the three broad categories. Four hundred and ninety-five bats representing eleven genera in seven families were recorded. These were Epomophorus labiatus, E. wahlbergi, Cardioderma cor, Lavia frons, Myotis welwitschii, Scotoecus hirundo, S. leucogaster, Pipistrellus kuhlii, Mops condylurus, Chaerephon bemmeleni, Mormopterus sp., Hipposideros caffer, H. commersoni, Nycteris arge and Rhinolophus landeri. This was the first record of N. arge, M. welwitschii, C. bemmeleni and a Mormopterus species in eastern Kenya. The Combretum community was most equitable (E = 0.51) with nine bat species records, while farming areas had only four. The low species richness and increased dominance of a few generalist species on farms may be indicative of different levels of disturbance. Résumé On a déterminé la diversité et la distribution des chauves-souris dans quatre types de végétation dans et autour du Parc National de Meru, au Kenya, entre septembre 2000 et février 2001. Les études de l'habitat des chauves-souris se basaient sur la dominance et le couvert de certaines espèces végétales et sur les activités agricoles. On a capturé les chauves-souris en utilisant les filets standards (18m de long sur 2 m de haut) fixés sur des piquets d'environ 3 m de haut. La végétation fut grossièrement regroupée en prairie arborée à Acacia ou à Combretum, ou en brousse à Acacia-Commiphora, et étudiée suivant la méthode Braun-Blanquet. L'analyse des similarités floristiques a montré cinq assemblages d'espèces végétales dans ces trois grandes catégories. On a relevé 495 chauves-souris représentant onze genres appartenant à sept familles. Ce sont: Epomophorus labiatus, E. wahlberghi, Cardioderma cor, Lavia frons, Myotis welwitschii, Scotoecus hirundo, Scotophilus leucogaster, Pipistrellus kuhlii, Mops condylurus, Chaerephon bemmeleni, Mormopterus sp., Hipposideros caffer, H. commersoni, Nycteris arge et Rhinolophus landeri. Ce sont les premiers cas rapportés pour N. arge, M. welwitschii, C. bemmemeni et pour une espèce de Mormopterus dans l'est du Kenya. La communautéà Combretum était la plus équitable (E = 0,51), avec neuf espèces de chauves-souris rapportées, alors que les aires cultivées n'en comptaient que quatre. La faible richesse en espèces et la dominance croissante de quelques espèces généralistes dans les fermes pourraient indiquer divers degrés de perturbation. [source] Muscular design in the equine interosseus muscleJOURNAL OF MORPHOLOGY, Issue 6 2006Carl Soffler Abstract We studied the forelimb interosseus muscle in horses, Equus caballus, to determine the muscular properties inherent in its function. Some authors have speculated that the equine interosseus contains muscle fibers at birth only to undergo loss of these fibers through postnatal ontogeny. We describe the muscle fibers in eight interosseus specimens from adult horses. These fibers were studied histochemically using myosin ATPase studies and immunocytochemically using several antibodies directed against type I and type II myosin heavy chain antibodies. We determined that 95% of the fibers were type I, presumed slow-twitch fibers. All fibers exhibited normal morphological appearance in terms of fiber diameter and cross-sectional area, suggesting that the muscles are undergoing normal cycles of recruitment. SDS-PAGE studies of myosin heavy chain isoforms were consistent with these observations of primarily slow-twitch muscle. Fibers were determined to be ,800 ,m long when studied using nitric acid digestion protocols. Short fiber length combined with high pinnation angles suggest that the interosseus muscle is able to generate large amounts of force but can produce little work (measured as pulling the distal tendon proximally). While the equine interosseus muscle has undergone a general reduction of muscle content during its evolution, it remains composed of a significant muscular component that likely contributes to forelimb stability and elastic storage of energy during locomotion. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Verrucophora farcimen gen. et sp. nov. (Dictyochophyceae, Heterokonta),a bloom-forming ichthyotoxic flagellate from the Skagerrak, Norway,JOURNAL OF PHYCOLOGY, Issue 5 2007Bente Edvardsen Since 1998, a heterokont flagellate initially named Chattonella aff. verruculosa has formed recurrent extensive blooms in the North Sea and the Skagerrak, causing fish mortalities. Cells were isolated from the 2001 bloom off the south coast of Norway, and monoalgal cultures were established and compared with the Chattonella verruculosa Y. Hara et Chihara reference strain NIES 670 from Japan. The cells in Norwegian cultured isolates were very variable in size and form, being large oblong (up to 34 ,m long) to small rounded (5,9 ,m in diameter) with two unequal flagella, numerous chloroplasts, and mucocysts. The SSU and partial LSU rDNA sequences of strains from Norway and Japan were compared and differed by 0.4% (SSU) and 1.3% (LSU), respectively. Five strains from Norway were identical in the LSU rDNA region. Phylogenetic analyses based on heterokont SSU and concatenated SSU + LSU rDNA sequences placed C. aff. verruculosa and the Japanese C. verruculosa within the clade of Dictyochophyceae, with the picoflagellate Florenciella parvula Eikrem as the closest relative. Ultrastructure, morphology, and pigment composition supported this affinity. We propose the name Verrucophora farcimen sp. et gen. nov. for this flagellate and systematically place it within the class Dictyochophyceae. Our studies also show that C. verruculosa from Japan is genetically and morphologically different but closely related to V. farcimen. The species is transferred from the class Raphidophyceae to the class Dictyochophyceae and renamed Verrucophora verruculosa. We propose a new order, Florenciellales, to accommodate V. farcimen, V. verruculosa, and F. parvula. [source] Spatial variability of O layer thickness and humus forms under different pine beech,forest transformation stages in NE GermanyJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2006Oliver Bens Abstract Spatial variability of humus layer (O layer) thicknesses can have important impacts upon soil water dynamics, nutrient storage and availability, as well as plant growth. The purpose of the present study was to elucidate the impact of forest-transformation practices on the spatial variability of O layer thicknesses. The study focused on the Kahlenberg forest area (NE Germany) with stands of Scots pine (Pinus sylvestris) and European beech (Fagus sylvatica) of different age structures that form a transformation chronosequence from pure Scots pine stands towards pure European beech stands. Topsoil profiles including both, the O layer and the uppermost humic mineral soil horizon were excavated at intervals of 0.4 m along 15,20 m long transects, and spatial variability of O layer thicknesses was quantified by variogram analysis. The correlation lengths of total O layer thickness increased in the sequence consisting of pure pine stand (3.1 m) , older mixed stand (3.7 m) , pure beech stand (4.5 m), with the exception of the younger mixed stand, for which no correlation lengths of total O layer thickness could be determined. The degree of spatial correlation, i.e., the percentage of the total variance which can be described by variograms, was highest for the two monospecies stands, whereas this percentage was distinctly lower for the two mixed stands. A similar minimum for the two mixed stands was observed for the correlation lengths of the Oh horizon. These results suggest that the spatial structures of forest-transformation stands may be interpreted in terms of a disturbance (in the form of the underplanting of beech trees). After this disturbance, the forest ecosystem requires at least 100 y to again reach relative equilibrium. These findings are in line with the results of other soil-related investigations at these sites. Räumliche Variabilität der Humuslagenmächtigkeit und Humusformen in verschiedenen Stadien des Waldumbaus von Kiefer zu Buche in NO-Deutschland Die räumliche Variabilität der Humusauflagenmächtigkeit kann einen bedeutenden Einfluss auf die Bodenwasserdynamik, Nährstoffspeicherung und -verfügbarkeit sowie das Pflanzenwachstum haben. Ziel dieser Studie war es, die Auswirkungen von Waldumbaumaßnahmen auf die räumliche Verteilung der Auflagehumusmächtigkeiten zu untersuchen. Im Forstrevier Kahlenberg, mit Beständen von Kiefer (Pinus sylvestris) und Buche (Fagus sylvatica) unterschiedlichen Alters, welche eine Transformations-Chronosequenz von einem Kiefern-Reinbestand hin zu einem reinen Buchenbestand darstellen, wurden Humusprofile entlang von 15,20 m langen Transekten in Abständen von 0,4 m aufgenommen. Die räumliche Variabilität der Mächtigkeiten der Auflagehumushorizonte wurde durch Variogramm-Analysen quantifiziert. Die Korrelationslängen der Mächtigkeiten des gesamten Auflagehumus stiegen in der Reihenfolge reiner Kiefernbestand (3,1 m) , älterer Mischbestand (3,7 m) , reiner Buchenbestand (4,5 m) an. Aus dieser Reihe fällt der jüngere Mischbestand heraus; für ihn konnten keine Korrelationslängen ermittelt werden. Der Grad der räumlichen Korrelation, d. h. der Anteil der gesamten Varianz, der durch Variogramme beschrieben wird, ist für die beiden Reinbestände am höchsten, während er für die beiden Mischbestände deutlich geringer ist. Ein ähnliches Minimum für die beiden Mischbestände ergibt sich, wenn nur die Korrelationslängen der Oh-Mächtigkeiten betrachtet werden. Diese Ergebnisse deuten darauf hin, dass die räumlichen Strukturen von Waldumbaubeständen im Sinne einer Störung gedeutet werden können (wobei die Umbaumaßnahme und der Unterbau mit Buchen die Störung darstellt). Diese Störung dauert offenbar mindestens 100 a an. Dieser Befund stimmt mit den Ergebnissen aus Studien zu weiteren relevanten Bodeneigenschaften an Forststandorten im nordostdeutschen Tiefland überein. [source] RUNOFF NUTRIENT AND FECAL COLIFORM CONTENT FROM CATTLE MANURE APPLICATION TO FESCUE PLOTS,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2000D. R. Edwards ABSTRACT: Grazed pastures represent a potential source of non-point pollution. In comparison to other nonpoint sources (e.g., row-cropped lands), relatively little information exists regarding possible magnitudes of pollution from grazed pasture; how that pollution is affected by weather, soil, management and other variables; and how the pollution can be minimized. The objective of this study was to assess how the quality of runoff from fescue plots is influenced by duration of cattle manure application (4,12 weeks) and manure application strategy (none, weekly application of 1.4 kg/plot, and monthly application at 5.6 kg/plot). Additional analyses were performed to relate runoff quality to the timing of sample collection. The study was conducted at the University of Kentucky Maine Chance Agricultural Experiment Station north of Lexington. Plots (2.4 m wide by 6.1 m long) were constructed and established in Kentucky 31 fescue (Festuca arundinacea Schreb.) to represent pasture. Grazing was simulated by application of beef cattle manure to the plots. Runoff was generated by applying simulated rainfall approximately 4, S and 12 weeks following initiation of manure application. Runoff samples were collected and analyzed according to standard methods for nitrogen (N), phosphorus (P) and fecal coliforms (FC). Runoff concentrations of N and P from manure-treated plots were low and generally not consistently different from control plot concentrations or related to manure application strategy. Runoff FC concentrations from manure-treated plots were higher than from control plot concentrations. Runoff concentrations of ammonia N, total Kjeldahl N, ortho-P and FC decreased approximately exponentially in response to increasing time of sample collection. These findings suggest that manure deposition on well-managed pasture at the rates used in this study might have a negligible impact on nutrient content of runoff. [source] SIZE-AND AGE-CLASS SEGREGATION OF BOWHEAD WHALES SUMMERING IN NORTHERN FOXE BASIN: A PHOTOGRAMMETRIC ANALYSISMARINE MAMMAL SCIENCE, Issue 2 2003Susan E. Cosens Abstract To determine whether Hudson Bay-Foxe Basin bowhead whales segregate on the basis of age, whales summering in northern Foxe Basin, were aerially photographed in August of 1996, 1997, and 1998. Image lengths on either the negatives or contact prints were measured and total body lengths were estimated. In all three years the majority of whales photographed were ,13.5 m long. Calves and juveniles made up 89.3%, 96.6%, and 79.3% of the total number of measured whales in 1996 (n = 28), 1997 (n = 30) and 1998 (n = 29) respectively. The number of bowheads >13.5 m, the approximate size at which females reach sexual maturity, that were photographed was directly proportional to the number of calves photographed. Our results indicate that northern Foxe Basin bowheads are part of a more widely distributed stock. Adult males and resting adult females apparently summer in another part of the range, probably northwestern Hudson Bay. Northern Foxe Basin appears to be used as a summer feeding area by cows with young-of-the-year calves and by juveniles. [source] STATUS, RELATIONSHIPS, AND DISTRIBUTION OF MESOPLODON BOWDOINI ANDREWS, 1908 (CETACEA: ZIPHIIDAE)MARINE MAMMAL SCIENCE, Issue 3 2001Alan N. Baker Abstract The specific status of Mesoplodon bowdoini Andrews is reviewed and new information on its morphology, reproduction, and distribution is presented. This species of beaked whale, known only from 35 specimens, has a southern, circumpolar distribution north of the Antarctic convergence, between 32° and 54°30,S. It shares with M. bahamondi Reyes, Van Waerebeek, Cárdenas and Yáñez from the south Pacific Ocean including New Zealand (this paper) and M. carlhubbsi Moore from the north Pacific, a number of morphological features such as prominential notches in the maxillary bones in the skull. It is less similar to M. stejnegeri True from the north Pacific and M. ginkgodens Nishiwaki and Kamiya from the tropical Indo-Pacific. Mesoplodon bowdoini can be distinguished from all other species of Mesoplodon by the shape of its teeth (male and female), and differences in the morphology of its skull, especially the proportions of the rostrum, separation of the nasals, the shape of the prominential notches, and the nature of the antorbital processes. The species' distinguishing external characteristics are: a robust body up to about 4.50 m long; a low melon and short, thick beak; an elevated jawline posteriorly; and a low, blunt-tipped, triangular dorsal fin. The occurrence of fetuses of M. bowdoini in May and September, and perinatal juveniles in May and June, indicates a summer-autumn breeding season in the New Zealand region; the length at birth is estimated at about 2.20 m. [source] The Sirente crater field, ItalyMETEORITICS & PLANETARY SCIENCE, Issue 11 2002Jens ORMö They are located in the Sirente plain within the mountains of the Abruzzo region, central Italy. The craters are distributed in a field 450 m long and 400 m wide. This field consists of ,17 smaller craters close to a larger main crater. The main crater is located in the southern end of the crater field and is 140 m long and 115 m wide, measured rim-to-rim. It has a well-developed, saddle-shaped rim that rises at a maximum 2.2 m above the surrounding plain. Radiocarbon dating of the target surface preserved below the rim gave a calibrated age of formation at about a.d. 412 (1650 ± 40 radiocarbon years b.p.). This young age is consistent with the apparent little modification of the rim. The morphology of the main crater and its relation to a crater field strongly points to its origin by impact from a projectile that broke up during its passage through the atmosphere. Quartz is very rare in the target and no planar deformation features have been found so far. The rim material and the upper 4 m of the main crater infill are impregnated with ferric oxides, which gives a more reddish colour compared to the other sediments of the plain. Rusty crusts with high Fe and Mn content occur in the rim material, but have not been found in the plain's sediments. Some of these crusts can be separated by magnet, and have sporadic micron-sized Ni-rich granules. The main crater is in the size range of the craters with explosive dispersion of the projectile and has many features comparable to both large experimental and meteoritic impact craters formed in loose sediments. We suggest that this crater represents a rare example of well-preserved, small impact crater formed in unconsolidated target materials. [source] Cladosiphon umezakii sp. nov. (Ectocarpales, Phaeophyceae) from JapanPHYCOLOGICAL RESEARCH, Issue 3 2007Tetsuro Ajisaka SUMMARY The new species Cladosiphon umezakii Ajisaka (Ectocarpales, Phaeophyceae) is described from Japan based on morphology and DNA sequences. The species resembles Cladosiphon okamuranus Tokida in its gross morphology; somewhat slimy, cylindrical, multiaxial and sympodial erect thallus, arising from a small disc-shaped holdfast, and branching once to twice. However, C. umezakii has considerably longer assimilatory filaments (up to 840 ,m long, composed of up to 90 cells) than any known taxa of the genus. The species is a winter to spring annual, growing on lower intertidal to subtidal rocks of more or less exposed sites on the north-eastern coast of Kyushu and on both the Pacific and the Sea of Japan coasts of Honshu. Specimens from the Sea of Japan coast had both unilocular and plurilocular zoidangia, whereas those from Kyushu and from the Pacific had only unilocular zoidangia. Unilocular zoidangia were formed on the basal part of assimilatory filaments, and plurilocular ones were transformed from the distal part of assimilatory filaments. DNA sequences of the Rubisco-spacer (rbc -spacer) region and the nuclear rDNA ITS region (ITS1, 5.8S and ITS2) supported the distinctness of the species. [source] Stromules: Mobile Protrusions and Interconnections Between PlastidsPLANT BIOLOGY, Issue 3 2001J. C. Gray Abstract: Stroma-filled tubules, recently named stromules, extend from the surface of plastids in most cell types and plant species examined. Stromules are highly dynamic structures, continuously and rapidly changing shape. They have been shown to interconnect plastids and permit the exchange of green fluorescent protein (GFP) between plastids. Stromules are enclosed by the inner and outer plastid envelope membranes and are 0.4 - 0.8 ,m in diameter and up to 65 ,m long. Movement of stromules is dependent on the actin cytoskeleton and the ATPase activity of myosin. Stromules are more abundant in cells containing a relatively small plastid volume and provide a means of enormously increasing the plastid surface area. Many important questions on the structure, function and mobility of stromules remain unanswered. [source] Comparative spermatogenesis, spermatocytogenesis, and spermatozeugmata formation in males of viviparous species of clinid fishes (Teleostei: Clinidae, Blennioidei)THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 3 2007Lev Fishelson Abstract Spermatogenesis and spermatocytogenesis in 16 species of viviparous clinid fishes (Clinidae, Blennioidei) from various localities were followed for the first time by means of light and electron microscopy. The testes of the studied species are of the lobular type, with germinal stem cells situated at the apical ends of the lobules and a vas efferens along the internal margin. Maturation of the spermatides takes place in spermatocysts formed by Sertoli cells around the B-spermatogonia. The gradual condensation and relocation of the chromosomes along the nuclei membranes are highly prominent in this process, which can be divided into several stages. Anisodiametric and slightly flattened sperm heads are eventually formed, 0.4,0.5 ,m in diameter and 7.5 ± 1 ,m long, bearing 80 ± 15 ,m long flagella. The sperms are packed into spermatozeugmata within the spermatocysts, enveloped and penetrated by the mucotic material of the Sertoli cells. With division of the germ cells and maturation of the spermatids, the spermatocyst dimensions increase, attaining 40 ± 8 ,m in diameter in the smaller species of Heteroclinus, and up to 90 ± 10 ,m in the larger males of Clinus superciliosus and C. cottoides. Accordingly, the volume of the maturing spermatocysts attains ca. 1,300 ± 100 ,m3 in the smaller species, and ca. 6,500 ± 300 ,m3 in the larger ones. As sperm head volume is ca. 2.24 ,m3, the number of sperm in the smallest mature spermatocysts reaches ca. 440 and in the largest over 2,900. Upon release from the cysts, the spermatozeugmata are transported along the sperm ducts to the posterior ampullae where they are stored in the epididymis. During copulation, the sperms are transported from there to the female via the intromittent organ. The sperm formation parameters and their structure and numbers are discussed. Anat Rec Part A, 2007. © 2007 Wiley-Liss, Inc. [source] Light and Electron Microscopy of the Spore of Myxobolus heckelii n. sp. (Myxozoa), Parasite from the Brazilian Fish Centromochlus heckelii (Teleostei, Auchenipteridae)THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 6 2009CARLOS AZEVEDO ABSTRACT. A myxosporean parasitizing the gill filaments of the freshwater teleost fish Centromochlus heckelii collected in the Tocantins River (Lower Amazonian Region, Brazil) is described using light and electron microscopy. This parasite produces spherical to ellipsoidal cyst-like plasmodia up to 250 ,m in diameter, with a thick wall strengthened by several stratified juxtaposed crossed collagen layers, whose thickness varies according to the number of the layers. Several compressed fibroblasts are observed among the collagen fibrils. Deposits of spherical dense material are scattered at the internal periphery of the cysts. Plasmodia and different developmental stages, including immature and mature spores, filled the central region of the cysts. The spore body is ellipsoidal in valvar view and biconvex in sutural view. It is formed by two equal-sized and symmetric valves measuring 12.7 ,m long (12.2,13.1) (n=50), 6.6 ,m wide (6.3,6.9) (n=25), and 4.0 ,m (3.7,4.4) (n=20) thick. A thin layer formed by fine and anastomosed microfibrils is observed at the spore surface. Two equal, elongated pyriform polar capsules measure 2.9 ,m (2.7,3.3) × 1.7 ,m (1.4,2.0) (n=25), each containing four or five oblique polar filament coils. The binucleated sporoplasm contains numerous spherical sporoplasmosomes, glycogen particles, and a large vacuole with fine granular matrix. Based on the morphological and ultrastructural differences and specificity of the host, we describe this isolate as a new myxosporidian, Myxobolus heckelii n. sp. (Myxozoa, Myxosporea). [source] A New Species of Myxozoa, Henneguya rondoni n. sp. (Myxozoa), from the Peripheral Nervous System of the Amazonian Fish, Gymnorhamphichthys rondoni (Teleostei)THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 3 2008CARLOS AZEVEDO ABSTRACT. Henneguya rondoni n. sp. found in the peripheral lateral nerves located below the two lateral lines of the fish Gymnorhamphichthys rondoni (Teleostei, Rhamphichthyidae) from the Amazon river is described using light and electron microscopy. Spherical to ellipsoid cysts measuring up to 110 ,m in length contained only immature and mature spores located in close contact with the myelin sheaths of the nervous fibres. Ellipsoidal spores measured 17.7 (16.9,18.1)-,m long, 3.6 (3.0,3.9)-,m wide, and 2.5 (2.2,2.8)-,m (n=25) thick. The spore body measuring 7.0 (6.8,7.3)-,m long was formed by two equal symmetric valves, each with an equal tapering tail 10.7 (10.3,11.0) ,m in length. The tails were composed of an internal dense material surrounded by an external homogeneous sheath of hyaline substance. The valves surrounded two equal pyriform polar capsules measuring 2.5 (2.2,2.8)-,m long and 0.85 (0.79,0.88)-,m (n=25) wide and a binucleated sporoplasm cell containing globular sporoplasmosomes 0.38 (0.33,0.42) ,m (n=25) in diam. with an internal eccentric dense structure with half-crescent section. Each polar capsule contains an anisofilar polar filament with 6,7 turns obliquely to the long axis. The matrix of the polar capsule was dense and the wall filled with a hyaline substance. The spores differed from those of previously described species. Based on the ultrastructural morphology of the spore and specificity to the host species, we propose a new species name H. rondoni n. sp. [source] | |||||||||||||||||||||||||||||||