2,371 research outputs found
Simultaneous multiplane imaging with reverberation multiphoton microscopy
Multiphoton microscopy (MPM) has gained enormous popularity over the years for its capacity to provide high resolution images from deep within scattering samples1. However, MPM is generally based on single-point laser-focus scanning, which is intrinsically slow. While imaging speeds as fast as video rate have become routine for 2D planar imaging, such speeds have so far been unattainable for 3D volumetric imaging without severely compromising microscope performance. We demonstrate here 3D volumetric (multiplane) imaging at the same speed as 2D planar (single plane) imaging, with minimal compromise in performance. Specifically, multiple planes are acquired by near-instantaneous axial scanning while maintaining 3D micron-scale resolution. Our technique, called reverberation MPM, is well adapted for large-scale imaging in scattering media with low repetition-rate lasers, and can be implemented with conventional MPM as a simple add-on.Accepted manuscrip
Neuronal imaging with ultrahigh dynamic range multiphoton microscopy
Multiphoton microscopes are hampered by limited dynamic range, preventing weak sample features from being detected in the presence of strong features, or preventing the capture of unpredictable bursts in sample strength. We present a digital electronic add-on technique that vastly improves the dynamic range of a multiphoton microscope while limiting potential photodamage. The add-on provides real-time negative feedback to regulate the laser power delivered to the sample, and a log representation of the sample strength to accommodate ultrahigh dynamic range without loss of information. No microscope hardware modifications are required, making the technique readily compatible with commercial instruments. Benefits are shown in both structural and in-vivo functional mouse brain imaging applications.R21 EY027549 - NEI NIH HH
Low frequency variability in the lower St. Lawrence Estuary
The lower St. Lawrence Estuary is a good example of wide estuaries with a second lateral boundary within several internal Rossby radii. We compare direct measurements from the 1979 lower St. Lawrence estuary mesoscale current meter array with satellite thermal images observed during the same period. The current field appears to show two quasi-steady states: one configuration is characterized by strong outflow along the north shore of the estuary with a transverse front at the mouth. The other current pattern is more typical of estuaries, with inflow along the north shore and outflow along the south shore. Transitions between these configurations are likely to be due to instability of the current field
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Wall thinning criteria for low temperature-low pressure piping
This acceptance criteria is intended to prevent gross rupture or rapidly propagating failure during normal and abnormal operating conditions. Pitting may be present in the carbon steel piping. While the acceptance criteria have provisions to preclude gross rupture through a pitted region, they do not protect against throughwall pit growth and subsequent leakage. Potential leakage through a pit in low pressure piping is less than the post-DBE design basis leakage. Both the uniform thinning and LTA criteria protect against leakage, since their potential for leakage is larger. The acceptance criteria protects against gross rupture due to general wall thinning, local wall thinning (LTA's), pitting, and fracture through weld defects. General wall thinning calculations are based on the restart criteria, SEP-24. LTA criteria for hoop stresses are based on ASME Code Case N-480 [open quotes]Examination Requirements for Pipe Wall Thinning Due to Single Phase Erosion and Corrosion[close quotes]. The LTA criteria for axial stress is based on an effective average thickness concept, which prevents plastic collapse of a locally thinned pipe. Limits on pit density, based on an effective cross section concept, are used to prevent gross rupture through a group of pits. The CEGB R-6 failure assessment diagram is used in the fracture evaluation, along with postulated weld defects. This criteria is intended for low temperature, low pressure piping systems. Corrosion and/or weld defects increase the peak stresses during normal operation and may lead to a reduction in fatigue life. Piping systems subject to significant thermal or mechanical fatigue will require additional analysis which is beyond the scope of this document
16 August 1947 EDDY County Specimen Collection Data
Specimen collected 16 August 1947. Original Locality: Black R. near mouth. Locality: Black River near confluence with Pecos River, northeast of town of Malaga.Catalog number: MSB118; Taxa: Lepomis cyanellus; Common name: green sunfish; Count of specimens: 3; Standard length:Catalog number: MSB187; Taxa: Lepomis macrochirus; Common name: bluegill ; Count of specimens: 17; Standard length:Catalog number: MSB246; Taxa: Lepomis megalotis; Common name: longear sunfish; Count of specimens: 26; Standard length:Catalog number: MSB331; Taxa: Gambusia affinis; Common name: western mosquitofish; Count of specimens: 55; Standard length:Catalog number: MSB359; Taxa: Gambusia affinis; Common name: western mosquitofish; Count of specimens: 8; Standard length:Catalog number: MSB372; Taxa: Ictalurus punctatus; Common name: channel catfish; Count of specimens: 2; Standard length:Catalog number: MSB414; Taxa: Pylodictis olivaris; Common name: flathead catfish; Count of specimens: 1; Standard length:Catalog number: MSB577; Taxa: Fundulus zebrinus; Common name: plains killifish; Count of specimens: 1; Standard length:Catalog number: MSB594; Taxa: Lucania parva; Common name: rainwater killifish; Count of specimens: 1135; Standard length:Catalog number: MSB677; Taxa: Pimephales promelas; Common name: fathead minnow; Count of specimens: 20; Standard length:Catalog number: MSB823; Taxa: Micropterus salmoides; Common name: largemouth bass; Count of specimens: 13; Standard length:Catalog number: MSB1202; Taxa: Notropis stramineus; Common name: sand shiner; Count of specimens: 16; Standard length:Catalog number: MSB1300; Taxa: Cyprinella lutrensis; Common name: red shiner; Count of specimens: 282; Standard length:Catalog number: MSB2223; Taxa: Moxostoma congestum; Common name: gray redhorse; Count of specimens: 8; Standard length:Catalog number: MSB3154; Taxa: Dorosoma cepedianum; Common name: gizzard shad; Count of specimens: 3; Standard length:Catalog number: MSB3194; Taxa: Carpiodes carpio; Common name: river carpsucker; Count of specimens: 12; Standard length:Catalog number: MSB3379; Taxa: Lepisosteus platostomus; Common name: shortnose gar; Count of specimens: 1; Standard length
Keep it simple: three indicators to deal with overfishing
Three simple fisheries indicators are presented: (i) percentage of mature fish in catch, with 100% as target; (ii) percent of specimens with optimum length in catch, with 100% as target; and (iii) percentage of ‘mega-spawners‘ in catch, with 0% as target, and 30–40% as representative of reasonable stock structure if no upper size limit exists. Application of these indicators to stocks of Gadus morhua, Sardinella aurita and Epinephelus aeneus demonstrate their usefulness. It is argued that such simple indicators have the potential to allow more stakeholders such as fishers, fish dealers, supermarket managers, consumers and politicians to participate in fisheries management and eventually hold and reverse the global pattern of convenience overfishing, which is defined here as deliberate overfishing sanctioned by official bodies who find it more convenient to risk eventual collapse of fish stocks than to risk social and political conflicts
19 August 1947 EDDY County Specimen Collection Data
Specimen collected 19 August 1947. Original Locality: Black River, T24S, R27E, S11 Locality: Black River, T24S, R27E, S11Catalog number: MSB132; Taxa: Lepomis cyanellus; Common name: green sunfish; Count of specimens: 3; Standard length:Catalog number: MSB171; Taxa: Lepomis macrochirus; Common name: bluegill ; Count of specimens: 4; Standard length:Catalog number: MSB180; Taxa: Lepomis macrochirus; Common name: bluegill ; Count of specimens: 12; Standard length:Catalog number: MSB228; Taxa: Micropterus punctulatus; Common name: spotted bass; Count of specimens: 3; Standard length:Catalog number: MSB231; Taxa: Micropterus punctulatus; Common name: spotted bass; Count of specimens: 1; Standard length:Catalog number: MSB253; Taxa: Lepomis megalotis; Common name: longear sunfish; Count of specimens: 3; Standard length:Catalog number: MSB299; Taxa: Gambusia affinis; Common name: western mosquitofish; Count of specimens: 425; Standard length:Catalog number: MSB492; Taxa: Lepomis gulosus; Common name: warmouth ; Count of specimens: 2; Standard length:Catalog number: MSB553; Taxa: Fundulus zebrinus; Common name: plains killifish; Count of specimens: 31; Standard length:Catalog number: MSB588; Taxa: Lucania parva; Common name: rainwater killifish; Count of specimens: 173; Standard length:Catalog number: MSB836; Taxa: Lepomis megalotis; Common name: longear sunfish; Count of specimens: 82; Standard length:Catalog number: MSB839; Taxa: Lepomis cyanellus; Common name: green sunfish; Count of specimens: 30; Standard length:Catalog number: MSB1215; Taxa: Notropis stramineus; Common name: sand shiner; Count of specimens: 118; Standard length:Catalog number: MSB1333; Taxa: Cyprinella lutrensis; Common name: red shiner; Count of specimens: 31; Standard length:Catalog number: MSB1361; Taxa: Cyprinella lutrensis; Common name: red shiner; Count of specimens: 3; Standard length:Catalog number: MSB1558; Taxa: Ictalurus lupus; Common name: headwater catfish; Count of specimens: 3; Standard length:Catalog number: MSB2195; Taxa: Astyanax mexicanus; Common name: Mexican tetra; Count of specimens: 27; Standard length:Catalog number: MSB2213; Taxa: Dionda episcopa; Common name: roundnose minnow; Count of specimens: 1; Standard length
Ion beam analysis of microcrystalline quartz artifacts from the Reed Mound Site, Delaware County, Oklahoma
Ion beam analysis (IBA) has been a powerful, non-destructive tool for archaeological research worldwide for over four decades, yet its full potential is seldom realized in North American archaeology. Herein the potential of particle induced X-ray emission spectrometry (PIXE) as a tool for future Ozarks chert provenance studies is evaluated based on its ability to facilitate (1) discrimination of Ozarks chert materials from different geological formations and (2) identification of discrete groups of artifacts from the same geological formation. In addition, PIXE was also used to evaluate the elemental heterogeneity of Ozarks chert materials. Thirty chert (microcrystalline quartz) artifacts were visually sorted and classified according to macroscopic features characteristic of certain chert resources from particular Ozarks geological formations. The elemental concentrations obtained from PIXE analysis underwent multivariate statistical analyses in order to gain insight from the data. The results indicate that PIXE could be a useful tool for assigning Ozarks chert materials to their respective geological formations, and possibly for determining regional or sub-regional provenance
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