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Selected AbstractsEffects of substrate geometry on growth cone behavior and axon branchingDEVELOPMENTAL NEUROBIOLOGY, Issue 11 2006Ginger S. Withers Abstract At the leading edge of a growing axon, the growth cone determines the path the axon takes and also plays a role in the formation of branches, decisions that are regulated by a complex array of chemical signals. Here, we used microfabrication technology to determine whether differences in substrate geometry, independent of changes in substrate chemistry, can modulate growth cone motility and branching, by patterning a polylysine grid of narrow (2 or 5 ,m wide) intersecting lines. The shape of the intersections varied from circular nodes 15 ,m in diameter to simple crossed lines (nodeless intersections). Time-lapse recordings of cultured hippocampal neurons showed that simple variations in substrate geometry changed growth cone shape, and altered the rate of growth and the probability of branching. When crossing onto a node intersection the growth cone paused, often for hours, and microtubules appeared to defasciculate. Once beyond the node, filopodia and lamellipodia persisted at that site, sometimes forming a collateral branch. At nodeless intersections, the growth cone passed through with minimal hesitation, often becoming divided into separate areas of motility that led to the growth of separate branches. When several lines intersected at a common point, growth cones sometimes split into several subdivisions, resulting in the emergence of as many as five branches. Such experiments revealed an intrinsic preference for branches to form at angles less than 90°. These data show that simple changes in the geometry of a chemically homogeneous substrate are detected by the growth cone and can regulate axonal growth and the formation of branches. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1183,1194, 2006 [source] Daily to seasonal cross-shore behaviour of quasi-persistent intertidal beach morphologyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2007S. Quartel Abstract In this study, an intertidal bar and trough system on the beach of Noordwijk, The Netherlands was monitored over a 15-month period in order to examine the daily to seasonal sequential cross-shore behaviour and to establish which conditions force or interrupt this cyclic bar behaviour. The beach morphology (bars and troughs) was classified from low-tide Argus video images based on surface composition. From the classified images, time series of the landward boundary of the bar and of the trough were extracted. The time series of the alongshore-averaged boundary positions described sawtooth motion with a period between 1 and 4 months, comprising gradual landward migration followed by abrupt seaward shifts. The abrupt seaward shift appeared to be a morphological reset induced by storm events, which lasted at least 30 h with a large average root-mean-square wave height (,2 m) and offshore surge level (,0·5 m), and a small trough (<20 m wide) in the pre-storm beach morphology. The time series of the boundary positions exhibited very little longer (seasonal) scale variability, but somewhat larger smaller (daily) scale variability. The bar boundary was found to be more dynamic than the trough boundary. Copyright © 2007 John Wiley & Sons, Ltd. [source] Overbank deposition along the concave side of the Red River meanders, Manitoba, and its geomorphic significanceEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2005Gregory R. Brooks Abstract Slow earth sliding is pervasive along the concave side of Red River meanders that impinge on Lake Agassiz glaciolacustrine deposits. These failures form elongated, low-angled (c. 6 to 10°) landslide zones along the valleysides. Silty overbank deposits that accumulated during the 1999 spring freshet extend continuously along the landslide zones over hundreds of metres and aggraded the lower slopes over a distance 50 to 80 m from the channel margin. The aggradation is not obviously related to meander curvature or location within a meander. Along seven slope profiles surveyed in 1999 near Letellier, Manitoba, the deposits locally are up to 21 cm thick and generally thin with increasing distance from, and height above, the river. Local deposit thickness relates to distance from the channel, duration of inundation of the landslide surface, mesotopography, and variations in vegetation cover. Immediately adjacent to the river, accumulated overbank deposits are up to 4 m thick. The 1999 overbank deposits also were present along the moderately sloped (c. 23 to 27°) concave banks eroding into the floodplain, but the deposits are thinner (locally up to c. 7 cm thick) and cover a narrower area (10 to 30 m wide) than the deposits within the landslide zones. Concave overbank deposition is part of a sediment reworking process that consists of overbank aggradation on the landslide zones, subsequent gradual downslope displacement from earth sliding, and eventually reworking by the river at the toe of the landslide. The presence of the deposits dampens the outward migration of the meanders and contributes to a low rate of contemporary lateral channel migration. Concave overbank sedimentation occurs along most Red River meanders between at least Emerson and St. Adolphe, Manitoba. © Her Majesty the Queen in right of Canada. [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] Geological controls on the formation of alluvial meanders and floodplain wetlands: the example of the Klip River, eastern Free State, South AfricaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2002S. Tooth Abstract Floodplain wetlands are common features of rivers in southern Africa, but they have been little studied from a geological or geomorphological perspective. Study of the upper Klip River, eastern Free State, South Africa, indicates strong geological controls on the formation of alluvial meanders and associated floodplain wetlands. Along this river, pronounced and abrupt changes in valley width are strongly linked to lithological variations. Where weakly cemented sandstone crops out, the Klip has laterally eroded bedrock and carved valleys up to 1500 m wide. In these valleys, the river meanders (sinuosity up to ,1·75) on moderate gradients (<0·001) within extensive floodplains marked by numerous oxbow lakes, backswamps and abandoned channels, many of which host substantial wetlands. In contrast, where highly resistant dolerite crops out, lateral erosion of bedrock is restricted, with the Klip tending instead to erode vertically along joints or fractures. Here, valleys are narrower (<200 m), channel-bed gradients are steeper (>0·003), the river follows a much straighter course (sinuosity ,1·10,1·34), and floodplains are restricted in width. Long-term landscape development in the Klip and numerous similar catchments depends on the interaction between fluvial processes in the sandstone and dolerite valleys. In the sandstone valleys, vertical erosion rates are controlled by erosion rates of the more resistant dolerites downstream. Hence, in the short- to medium-term (decades to tens of thousands of years), lateral erosion dominates over vertical erosion, with the river concomitantly planing sandstone in the channel floor and reworking floodplain sediments. The thickness of alluvial fill in the sandstone valleys is limited (<4 m), but the resultant meanders are naturally dynamic, with processes such as point bar deposition, cutoff formation and channel avulsion resulting in an assemblage of fluvial landforms. In the longer term (greater than tens of thousands of years), however, vertical erosion will occur in the sandstone valleys as the downstream dolerites are lowered by erosion, resulting in channel incision, floodplain abandonment, and desiccation of the wetlands. Identification of the geological controls on meander and wetland formation provides information vital for the design of effective management guidelines for these ecologically rich habitats, and also contributes to a better understanding of rivers that are intermediate between fully alluvial and fully bedrock. Copyright © 2002 John Wiley & Sons, Ltd. [source] Dry film microchips for miniaturised separationsELECTROPHORESIS, Issue 24 2009Rosanne M. Guijt Abstract In this work microfluidic devices were made from the dry film photoresist Ordyl SY330, characterised by optical and electron microscopy and used for electrophoretic separations. A simple and fast microfabrication process was developed for the fabrication of channels that are 50,,m wide and 30,,m in height, requiring only the use of an office laminator, a hot plate, an exposure source and mask and an electric drill to make four microdevices in less than 1,h. The optical properties of the photoresist were studied and the resist showed significant absorbance below 370,nm and 570,630,nm, and had an optical transmission of 80% between 400 and 550,nm. Fluorescence emission over the region of maximum transmission was low allowing these devices to be used for fluorescence detection at 488/512,nm. Electrophoretic separation of APTS and three derivatised sugars was performed in 20,mM phosphate buffer, pH 2.5 with efficiencies of the three sugars of 40,000 plates (2,100,000,plates/m) within 30,s at a field strength of 500,V/cm. The simple fabrication process also allowed microchannels to be easily filled with chromatography particles before sealing, avoiding the challenging task of slurry packing, and the potential of these devices for liquid chromatography was demonstrated by the extraction of fluorescein onto anion exchange particles. [source] Underivatized cyclic olefin copolymer as substrate material and stationary phase for capillary and microchip electrochromatographyELECTROPHORESIS, Issue 15 2008Omar Gustafsson Abstract We report, for the first time, the use of underivatized cyclic olefin copolymer (COC, more specifically: Topas) as the substrate material and the stationary phase for capillary and microchip electrochromatography (CEC), and demonstrate chromatographic separations without the need of coating procedures. Electroosmotic mobility measurements in a 25,,m id Topas capillary showed a significant cathodic EOF that is pH-dependent. The magnitude of the electroosmotic mobility is comparable to that found in glass substrates and other polymeric materials. Open-tubular CEC was employed to baseline-separate three neutral compounds in an underivatized Topas capillary with plate heights ranging from 5.3 to 12.7,,m. The analytes were detected using UV absorbance at 254,nm, thus taking advantage of the optical transparency of Topas at short wavelengths. The fabrication of a Topas-based electrochromatography microchip by nanoimprint lithography is also presented. The microchip has an array of pillars in the separation column to increase the surface area. The smallest features that were successfully imprinted were around 2,,m wide and 5,,m high. No plasma treatment was used during the bonding, thus keeping the surface properties of the native material. An RP microchip electrochromatography separation of three fluorescently labeled amines is demonstrated on the underivatized microchip with plate heights ranging from 3.4 to 22,,m. [source] A confocal micro-endoscopic investigation of the relationship between the microhardness of carious dentine and its autofluorescenceEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2010Avijit Banerjee Banerjee A, Cook R, Kellow S, Shah K, Festy F, Sherriff M, Watson T. A confocal micro-endoscopic investigation of the relationship between the microhardness of carious dentine and its autofluorescence. Eur J Oral Sci 2010; 118: 75,79. © 2010 The Authors. Journal compilation© 2010 Eur J Oral Sci This study aimed to investigate the null hypothesis that there is no relationship between the microhardness of carious dentine and its native autofluorescence (AF). Six extracted, carious molars were sectioned through natural lesions in the mesio-distal longitudinal plane. The Knoop microhardness (Knoop hardness number, KHN) of the cut surfaces of each sample was recorded at regular intervals through sound and carious dentine. Confocal fibre-optic micro-endoscopic (CFOME) examination of the carious dentine and the sound dentine was carried out at the same intervals using the Cellvizio system (600 ,m wide, flat-end probe) with an excitation wavelength of 488 nm. The blindly collected numerical data were analysed using the original microhardness KHN. The data analysis indicated that the autofluorescence signals increased significantly when the microhardness of dentine dropped below 25 KHN. Therefore, the null hypothesis was disproved, and it was concluded from this investigation that the autofluorescent signal intensity recorded using CFOME could produce an objective and reproducible correlation to the microhardness of carious dentine. Confocal fibre-optic micro-endoscopic examination could have clinical potential as a technology to help delineate the carious dentine that might be excavated in a clinical procedure in vivo. [source] Sourcing carbonate pointed stones from the barrier beach of Mantoloking, New Jersey, USAGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2006John P. Vermylen Over 500 previously unidentified, symmetric pointed stones of similar size, shape, color, and texture have been found on the barrier beach of Mantoloking, New Jersey, since 1940. Petrographic, stereo, and scanning electron microscopy analysis reveals that the stones are made of either a biomicritic packstone composed of 50% siliceous microfossil remains ( including sponge spicules and radiolaria) embedded in a micrite matrix or a limestone with abundant angular quartz grains (50,150 ,m wide) surrounded by a calcite matrix. The distinctive shape of the Mantoloking stones is most similar to whetstones used for sharpening scythes. We conducted a worldwide search and discovered one producer of carbonate whetstones: a company in the town of Pradalunga in Northern Italy. Microscope analysis reveals that the Pradalunga source rocks are exact matches for the spicule-rich limestone and angular quartz-rich limestone found in the Mantoloking collection. The whetstones are most likely lost cargo from a wreck offshore of Mantoloking, but the exact source may never be known. © 2006 Wiley Periodicals, Inc. [source] The mechanism of fluid infiltration in peridotites at Almklovdalen, western NorwayGEOFLUIDS (ELECTRONIC), Issue 3 2002O. Kostenko Abstract A major Alpine-type peridotite located at Almklovdalen in the Western Gneiss Region of Norway was infiltrated by aqueous fluids at several stages during late Caledonian uplift and retrogressive metamorphism. Following peak metamorphic conditions in the garnet,peridotite stability field, the peridotite experienced pervasive fluid infiltration and retrogression in the chlorite,peridotite stability field. Subsequently, the peridotite was infiltrated locally by nonreactive fluids along fracture networks forming pipe-like structures, typically on the order of 10 m wide. Fluid migration away from the fractures into the initially impermeable peridotite matrix was facilitated by pervasive dilation of grain boundaries and the formation of intragranular hydrofractures. Microstructural observations of serpentine occupying the originally fluid-filled inclusion space indicate that the pervasively infiltrating fluid was characterized by a high dihedral angle (, > 60°) and ,curled up' into discontinuous channels and fluid inclusion arrays following the infiltration event. Re-equilibration of the fluid phase topology took place by growth and dissolution processes driven by the excess surface energy represented by the ,forcefully' introduced external fluid. Pervasive fluid introduction into the peridotite reduced local effective stresses, increased the effective grain boundary diffusion rates and caused extensive recrystallization and some grain coarsening of the infiltrated volumes. Grain boundary migration associated with this recrystallization swept off abundant intragranular fluid inclusions in the original chlorite peridotite, leading to a significant colour change of the rock. This colour change defines a relatively sharp front typically located 1,20 cm away from the fractures where the nonreactive fluids originally entered the peridotite. Our observations demonstrate how crustal rocks may be pervasively infiltrated by fluids with high dihedral angles (, > 60°) and emphasize the coupling between hydrofracturing and textural equilibration of the grain boundary networks and the fluid phase topology. [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] Guiding Cell Migration Using One-Way Micropattern Arrays,ADVANCED MATERIALS, Issue 8 2007G. Kumar A single NIH,3T3 fibroblast on a teardrop island, surrounded by a cell-resistant background, extends lamellipodia from both sharp and blunt ends. However, the staggered arrangement of the islands and preferential extension of lamellipodia parallel to the cell body only permit attachment of lamellipodia extended from the blunt end, resulting in exclusive counterclockwise migration (the figure is ca.,200,,m wide). [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] On the roles of deformation and fluid during rejuvenation of a polymetamorphic terrane: inferences on the geodynamic evolution of the Ruker Province, East AntarcticaJOURNAL OF METAMORPHIC GEOLOGY, Issue 8 2007G. PHILLIPS Abstract Evaluating pressure,temperature (P,T) conditions through mineral equilibria modelling within an amphibolite facies polymetamorphic terrane requires knowledge of the fluid content of the rocks. The Archean-Palaeoproterozoic basement rocks of the Ruker Province, East Antarctica, preserve evidence of three metamorphic events (M1,M3). Of particular interest is the M3 event, which is constrained to the early Palaeozoic (c. 550,480 Ma). Evaluation of the tectonic setting during this time is important because the Ruker Province is located within a critical region with respect to models of Gondwana assembly. Structural evidence of the early Palaeozoic event is preserved as large (up to ,500 m wide) high strain zones that cut the orthogneiss-metasedimentary basement (Tingey Complex) of the Ruker Province. Rocks within these zones have been thoroughly recrystallized and preserve a dominant shear fabric and M3 mineral assemblages that formed at P,T conditions of 4.0,5.2 kbar and 565,640 °C. Distal to these zones, rocks preserve more complex petrographic relationships with S1 and S2 foliations, being incompletely overgrown by M3 retrograde assemblages. We show that the mineral assemblages preserved during the M3 event are highly dependent on the availability of fluid H2O, which is strongly influenced by the structural setting (i.e. proximity to the high-strain zones). P,T structural and fluid flow constraints support a model of basin inversion during early Palaeozoic crustal rejuvenation in the Ruker Province. [source] FAULT-RELATED SOLUTION CLEAVAGE IN EXPOSED CARBONATE RESERVOIR ROCKS IN THE SOUTHERN APENNINES, ITALYJOURNAL OF PETROLEUM GEOLOGY, Issue 2 2001A. Billi The deformation associated with a number of kilometre-scale strike-slip fault zones which cut through outcropping carbonate rocks in the Southern Apennines was investigated at regional and outcrop scales. These faults trend roughly east-west and were studied at the Gargano Promontory on the Adriatic Coast (in the Apulian foreland) and in the Matese Mountains, about 120 km to the west (within the Apenninic fold-and-thrust belt). The fault zones are 200,300 m wide and typically comprise a core surrounded by a damage zone. Within fault cores, fault rocks (gouges and cataclasites) typically occur along master slip planes; in damage zones, secondary slip planes and solution cleavage are the most important planar discontinuities. The protolith carbonates surrounding the fault zone at Gargano show little deformation, but they are fractured in the Matese Mountains as a result of an earlier thrust phase. Cleavage surfaces in the damage zone of the studied faults are interpreted to be fault-propagation structures. Our field data indicate that cleavage-fault intersection lines are parallel to the normals of fault slip-vectors. The angle between a fault plane and the associated cleavage was found to be fairly constant (c. 40") at different scales of observation. Finally, the spacing of the solution cleavage surfaces appeared in general to be regular (with a mean of about 22 mm), although it was found to decrease slightly near a fault plane. These results are intended to provide a basis for predicting the architecture of fault zones in buried carbonate reservoirs using seismic reflection and borehole data. [source] An Evaluation of Qualitative Indexes of Physical Habitat Applied to Agricultural Streams in Ten U.S. States,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2010Robert M. Hughes Hughes, Robert M., Alan T. Herlihy, and Philip R. Kaufmann, 2010. An Evaluation of Qualitative Indexes of Physical Habitat Applied to Agricultural Streams in Ten U.S. States. Journal of the American Water Resources Association (JAWRA) 46(4): 792-806. DOI: 10.1111/j.1752-1688.2010.00455.x Abstract:, Assessment of stream physical habitat condition is important for evaluating stream quality globally. However, the diversity of metrics and methods for assessing physical habitat condition confounds comparisons among practitioners. We surveyed 51 previously sampled stream sites (0.0-6.3 m wide) located in regions of row-crop agriculture in Oregon, California, North Dakota, South Dakota, Nebraska, Iowa, Minnesota, Pennsylvania, Maryland, and West Virginia to evaluate the comparability of four indexes of physical habitat condition relative to each other. We also compared the indexes to previously calculated indexes of fish and macroinvertebrate condition. The physical habitat indexes included the Stream Visual Assessment Protocol Version 2 of the Natural Resources Conservation Service, the qualitative habitat evaluation index of the Ohio Environmental Protection Agency, the rapid bioassessment protocol of the United States Environmental Protection Agency (USEPA), and a qualitative physical habitat index based on USEPA quantitative physical habitat measurements. All four indexes were highly correlated with each other, but low-to-moderately correlated with biotic index scores for fish and macroinvertebrate assemblages. Moderately high correlations occurred between some macroinvertebrate biotic index scores and quantitative metrics. We conclude that additional research is needed to increase the predictive and diagnostic capabilities of qualitative physical habitat indexes. [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] Shock-induced melting, recrystallization, and exsolution in plagioclase from the Martian lherzolitic shergottite GRV 99027METEORITICS & PLANETARY SCIENCE, Issue 4 2006Deqiang Wang The recrystallized plagioclase contains lamellae of pyroxene, olivine, and minor ilmenite (<1 ,m wide). Both the pyroxene and the olivine inclusions enclosed in plagioclase and grains neighboring the plagioclase were partially melted into plagioclase melt pools. The formation of these lamellar inclusions in plagioclase is attributed to exsolution from recrystallizing melt. Distinct from other Martian meteorites, GRV 99027 contains no maskelynite but does contain recrystallized plagioclase. This shows that the meteorite experienced a slower cooling than maskelynite-bearing meteorites. We suggest that the parent rock of GRV 99027 could have been embedded in hot rocks, which facilitated a more protracted cooling history. [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] Cryogenic sediment-filled wedges, northern Delaware, USAPERMAFROST AND PERIGLACIAL PROCESSES, Issue 4 2004Mary D. Lemcke Abstract Wedge-like sedimentary structures at two sites in northern Delaware USA are located at the erosional surface of, and extend into, channel deposits of the fluvial, mid-Pleistocene Columbia Formation. The wedges are 0.25,0.60,m wide at the top, 1.0,1.5,m in vertical extent, contain moderate to poorly sorted, and vertically-stratified sediment, and are overlain unconformably by a layer of wind-blown silt. Several hypotheses for the formation and infill of the wedges were evaluated using detailed physical, stratigraphic, and sedimentological information. The most likely explanation for the features is that they are relict cryogenic structures formed by thermal-contraction cracking in permafrost, and filled with wind-blown sediments derived from the Columbia Formation. The wedges are believed to have formed in the tundra environment that existed in northern Delaware, south of the Laurentide Ice Sheet, during the coldest parts of the Wisconsinan glaciation. Copyright © 2004 John Wiley & Sons, Ltd. [source] Evidence for late-Pleistocene permafrost in the New Jersey Pine Barrens (latitude 39°N), eastern USAPERMAFROST AND PERIGLACIAL PROCESSES, Issue 3 2003Hugh M. French Abstract Relict sand wedges, up to 2.5,m deep and 0.4,m wide, are present in the Pine Barrens of southern New Jersey. They indicate the previous existence of permafrost. The wedges are composed predominantly of sand that shows evidence of wind transport and abrasion. Optically-stimulated-luminescence dating of infill material indicates that thermal-contraction-cracking and emplacement of the sand infill must have occurred during two separate periods during the Late Pleistocene. The most recent was in Late Wisconsinan times,,15,18,ka. An earlier period of permafrost conditions is indicated by dates >55,65,ka. On both occasions, the Late-Pleistocene ice sheets would have advanced as far south as northern New Jersey and strong winds would have occurred in the lower mid-latitudes. The sandy soils of the Pine Barrens would have allowed the ice-marginal periglacial zone to extend southwards into southern New Jersey. The sparse tundra vegetation on the sandy substrate, with its relatively high thermal conductivity, would have permitted deep frost penetration because the ,thermal offset' would have been minimized. A mean annual air temperature of between ,3.0°C and ,4.0°C is inferred. Permafrost was probably discontinuous and less than 10,15,m in thickness. Episodes of permafrost thaw are indicated by the widespread occurrence of deformed sediments (,thermokarst involutions') and by various small-scale non-diastrophic structures associated with bog ironstone beds. The presence of soil (ground) wedges in southern New Jersey and adjacent Delaware also suggest conditions of deep seasonal frost, probably when the most recent permafrost degraded. Copyright © 2003 John Wiley & Sons, Ltd. [source] Inkjet printed, conductive, 25 ,m wide silver tracks on unstructured polyimidePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2009Henning Meier Abstract 25 ,m wide, conductive silver tracks on untreated and unstructured polyimide have been produced by inkjet printing using standard 10 pL printheads. This was achieved by reducing the droplet size to ,2 pL by tailoring the waveform and by heating the print cartridge and the substrate to 55 °C. A simple formula was used to predict the track width. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Closely spaced external standard: a universal method of achieving 5 ppm mass accuracy over the entire MALDI plate in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2003Eugene Moskovets Close deposition of the sample and external standard was used in axial matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to achieve mass accuracy equivalent to that obtained with an internal standard across the entire MALDI plate. In this work, the sample and external standard were deposited by continuous deposition in separate traces, each approximately 200,,m wide. The dependence of the mass accuracy on the distance between the sample and standard traces was determined across a MALDI target plate with dimensions of 57.5,mm,×,57.0,mm by varying the gap between the traces from 100,,m to 4,mm. During acquisition, two adjacent traces were alternately irradiated with a 200-Hz laser, such that the peaks in the resulting mass spectra combined the sample and external standard. Ion suppression was not observed even when the peptide concentrations in the two traces differed by more than two orders of magnitude. The five peaks from the external standard trace were used in a four-term mass calibration of the masses of the sample trace. The average accuracy across the whole plate with this method was 5,ppm when peaks of the sample trace had signal-to-noise ratios of at least 30 and the gap between the traces was approximately 100,,m. This approach was applied to determining peptide masses of a reversed-phase liquid chromatographic (LC) separation of a tryptic digest of , -galactosidase deposited as a long serpentine trace across the MALDI plate, with accuracy comparable to that obtainable using internal calibration. In addition, the eluent from reversed-phase LC separation of a strong cation-exchange fraction containing tryptic peptides from a yeast lysate along with the closely placed external standard was deposited on the MALDI plate. The data obtained in the MS and MS/MS modes on a MALDI-TOF/TOF mass spectrometer were combined and used in database searching with MASCOT. Since the significant score is a function of mass accuracy in the MS mode, database searching with high mass accuracy reduced the number of false positives and also added peptides which otherwise would have been eliminated at lower mass accuracy (false negatives). Copyright © 2003 John Wiley & Sons, Ltd. [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] The Gross and Micro Anatomy of the Accessory Sex Glands of the Male Agouti (Dasyprocta leporina)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2009W. M. Mollineau Summary This study was a follow up to the study on the gross anatomy of the male agouti (Dasyprocta leporina) reproductive system. The seminal vesicles of the agouti are lobulated structures. The mean diameter of the large lumen is 883.6 ± 76.83 ,m. The mucosa (24.1 ± 0.92 ,m), which is lined by pseudo-stratified columnar epithelium is thrown into folds, which often branch. The lamina muscularis mucosa is thin and is made of loose connective tissue containing blood vessels. The mucosa of the leaf-like coagulating glands of the agouti is folded. The mean diameter of the lumen is 488.3 ± 41.96 ,m. The mucosa contains tubuloalveolar glands, which have a mean length of 199.5 ± 28.83 ,m. The thin epithelium, 15.0 ± 1.25-,m wide, consists mostly of pseudo-stratified columnar cells. The epithelium also has surface modifications in the form of apical blebs and cilia. The epithelium of the agouti's lobulated prostate gland is also folded creating a large lumen with a mean diameter of 995.5 ± 55.70 ,m. The mucosa contains tubular and tubuloalveolar glands, each having a mean length of 134.4 ± 13.59 ,m. The epithelium (13.9 ± 1.16 ,m) consists of pseudo-stratified columnar cells. The pea-shaped bulbourethral gland (BG) of the agouti consists of convoluted tubular, mucous secretory units, which are irregularly shaped each with a mean length of 177.9 ± 7.10 ,m and a mean width of 63.5 ± 3.97 ,m. The BG of the agouti are ventro-lateral to the rectum and dorsally positioned to the pubic symphysis, and connected to the urethra by short ducts. [source] Display of a peer's face picture enhances the preference for a pen in preference testing in cowsANIMAL SCIENCE JOURNAL, Issue 5 2009Shigeru NINOMIYA ABSTRACT Using preference testing, we investigated the effect of a brush and a peer's face picture on the welfare of breeding beef cows. Four cows were used in experiment 1 and another four cows were used in experiment 2. An experimental barn consisted of two 3.5 square-meter pens, and a corridor measuring 1.6 m wide and 1.3 m long. During the experiment, either side of the pens were treated. In experiment 1, straw bedding was placed in a treated pen (condition B) in the first two trials, a brush was added in the treated pen (condition BB) in the next two trials, and a peer's face picture was displayed in the treated pen (condition BBF) in the last two trials. In experiment 2, condition B was applied for the first two trials, a peer's face picture was displayed in the treated pen (condition BF) in the next two trials, and condition BBF was applied for the last two trials. Each cow was housed alone from 09.00 hour to 15.00 h in the experimental barn during the six trials. The cows stayed in the treatment pen longer than in the non-treatment pen under all conditions in experiments 1 and 2. In experiment 1, the mean total time spent in the treatment pen was longer under condition BBF than under conditions B and BB. In experiment 2, the mean total time spent in the treatment pen was shorter under condition B than under conditions BF and BBF. The mean percentage of time spent ruminating was greater under condition BBF than under condition B. It is concluded that the cows preferred the peer's face picture in the isolated condition of preference testing in this study. [source] Priority habitats for the conservation of large river fish in the Ganges river basinAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2007Uttam Kumar Sarkar Abstract 1.Three classes of habitat used by groups of fish species classified as conservation and management priorities were developed for the Gerua River (also known as the Girwa River, Karnali River) in the Ganges river basin. This river is large (mean annual discharge ca 1500 m3 s,1, up to 900 m wide), surrounded by protected lands of India and Nepal, and upstream of major diversions and river alterations. 2.Fish and habitat sampling was conducted at 45 sites from 2000 to 2003. Data were analysed for 2172 fish of 14 species. Species and life stages found occupying a statistically distinct subset of the river habitats were grouped to identify classes of river habitat for conservation. 3.Most species and life-stage groups specialized on specific habitat conditions revealed by multivariate analyses of variance and a principal component analysis. The most numerous and diverse group (six species, 15 life stages) was associated with deep depositional habitats with sandy substrate. Two species covering three life stages were primarily oriented to erosional habitat marked by fast current velocity with pebble and cobble substrate. A third group of three species of adults and juveniles were intermediate in habitat use. 4.River conservation for fish faunas should maintain both erosional and depositional channel habitats with depths, substrates, and current velocity inclusive of the ranges reported. The erosional and depositional nature of the key habitats requires that rivers be maintained with flows capable of channel-forming functions. Copyright © 2006 John Wiley & Sons, Ltd. [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] | ||||||||||||||||||||||||||||