Alternative Penetrometers to Measure the Near Surface Strength of Soft Seafloor Soils

DTIC Science & Technology

2011-01-01

recorded data. The three probe types were a cone penetrometer (CPT), ball penetrometer (BPT), and a shear vane ( VST ). The CPT and BPT measure...electronically a continuous profile of tip and sleeve resistance as well as the porewater pressure during advancement. The VST records the undrained shear...test results and are compared with the VST shear strengths as shown on Figure 5 (Specimen 1) and Figure 6 (Specimen 2). The VST strengths compare

Maintenance of the Hanford cone penetrometer platform during fiscal year 1999

DOE Office of Scientific and Technical Information (OSTI.GOV)

IWATATE, D.F.

This SOW describes services requested of Applied Research and Associates, Inc. (ARA), as a commercial provider of cone penetrometer equipment and services, to provide routine inspection and minimum preventive maintenance on the Hanford CP Platform (CPP) during Fiscal Year 1999. This SOW specifically pertains to the maintenance of the CPP and associated support equipment and is limited in scope to routine preventive maintenance and identification of any deficiencies. ARA is the original manufacturer of the CPP and will conduct this work following the vendor-prepared maintenance schedule.

A continuous intrusion miniature cone penetration test system for transportation applications : final report.

DOT National Transportation Integrated Search

1999-01-01

The electronic cone penetrometer is a popular in situ investigation tool for site characterization. This research report describes the application of this proven concept of the cone penetration test (CPT) to highway design and construction control by...

Cone penetrometer comparison testing.

DOT National Transportation Integrated Search

2011-01-01

A total of 61 cone penetration tests were performed at 14 sites in the state of Wisconsin. Data : reinforced conclusions from practice in Minnesota and previously performed test programs : related to the Marquette Interchange and Mitchell interchange...

A bayesian approach for determining velocity and uncertainty estimates from seismic cone penetrometer testing or vertical seismic profiling data

USGS Publications Warehouse

Pidlisecky, Adam; Haines, S.S.

2011-01-01

Conventional processing methods for seismic cone penetrometer data present several shortcomings, most notably the absence of a robust velocity model uncertainty estimate. We propose a new seismic cone penetrometer testing (SCPT) data-processing approach that employs Bayesian methods to map measured data errors into quantitative estimates of model uncertainty. We first calculate travel-time differences for all permutations of seismic trace pairs. That is, we cross-correlate each trace at each measurement location with every trace at every other measurement location to determine travel-time differences that are not biased by the choice of any particular reference trace and to thoroughly characterize data error. We calculate a forward operator that accounts for the different ray paths for each measurement location, including refraction at layer boundaries. We then use a Bayesian inversion scheme to obtain the most likely slowness (the reciprocal of velocity) and a distribution of probable slowness values for each model layer. The result is a velocity model that is based on correct ray paths, with uncertainty bounds that are based on the data error. ?? NRC Research Press 2011.

Work plan for cone penetrometer comparison testing.

DOT National Transportation Integrated Search

2011-01-01

The work plan and experimental design are developed around aiding engineers and geologists within the : Wisconsin Department of Transportation to understand the mechanisms controlling cone penetration test : results so that they can decide when the t...

Feasibility of using cone penetrometer truck (CPT) to install time domain reflectometry (TDR) and fiber optic slope failure detectors in pavement structures.

DOT National Transportation Integrated Search

2011-02-01

A new method of cable installation using a heavy-duty Cone Penetration Test : (CPT) truck was developed and practiced successfully in this study. The coaxial and fiber : optic cables were pushed along with the cone rods by the hydraulic system integr...

Pit Latrine Fecal Sludge Resistance Using a Dynamic Cone Penetrometer in Low Income Areas in Mzuzu City, Malawi

PubMed Central

Chirwa, Charles F. C.; Hall, Ralph P.; Krometis, Leigh-Anne H.; Vance, Eric A.; Edwards, Adam; Guan, Ting; Holm, Rochelle H.

2017-01-01

Pit latrines can provide improved household sanitation, but without effective and inexpensive emptying options, they are often abandoned once full and may pose a public health threat. Emptying techniques can be difficult, as the sludge contents of each pit latrine are different. The design of effective emptying techniques (e.g., pumps) is limited by a lack of data characterizing typical in situ latrine sludge resistance. This investigation aimed to better understand the community education and technical engineering needs necessary to improve pit latrine management. In low income areas within Mzuzu city, Malawi, 300 pit latrines from three distinct areas were assessed using a dynamic cone penetrometer to quantify fecal sludge strength, and household members were surveyed to determine their knowledge of desludging procedures and practices likely to impact fecal sludge characteristics. The results demonstrate that there is a significant difference in sludge strength between lined and unlined pits within a defined area, though sludge hardened with depth, regardless of the pit type or region. There was only limited association between cone penetration depth and household survey data. To promote the adoption of pit emptying, it is recommended that households be provided with information that supports pit emptying, such as latrine construction designs, local pit emptying options, and cost. This study indicates that the use of a penetrometer test in the field prior to pit latrine emptying may facilitate the selection of appropriate pit emptying technology. PMID:28165378

Cone penetrometer testing and discrete-depth ground water sampling techniques: A cost-effective method of site characterization in a multiple-aquifer setting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zemo, D.A.; Pierce, Y.G.; Gallinatti, J.D.

Cone penetrometer testing (CPT), combined with discrete-depth ground water sampling methods, can significantly reduce the time and expense required to characterize large sites that have multiple aquifers. Results from the screening site characterization can then be used to design and install a cost-effective monitoring well network. At a site in northern California, it was necessary to characterize the stratigraphy and the distribution of volatile organic compounds (VOCs). To expedite characterization, a five-week field screening program was implemented that consisted of a shallow ground water survey, CPT soundings and pore-pressure measurements, and discrete-depth ground water sampling. Based on continuous lithologic informationmore » provided by the CPT soundings, four predominantly coarse-grained, water yielding stratigraphic packages were identified. Seventy-nine discrete-depth ground water samples were collected using either shallow ground water survey techniques, the BAT Enviroprobe, or the QED HydroPunch I, depending on subsurface conditions. Using results from these efforts, a 20-well monitoring network was designed and installed to monitor critical points within each stratigraphic package. Good correlation was found for hydraulic head and chemical results between discrete-depth screening data and monitoring well data. Understanding the vertical VOC distribution and concentrations produced substantial time and cost savings by minimizing the number of permanent monitoring wells and reducing the number of costly conductor casings that had to be installed. Additionally, significant long-term cost savings will result from reduced sampling costs, because fewer wells comprise the monitoring network. The authors estimate these savings to be 50% for site characterization costs, 65% for site characterization time, and 60% for long-term monitoring costs.« less

Development of an Automated Airfield Dynamic Cone Penetrometer (AADCP) Prototype and the Evaluation of Unsurfaced Airfield Seismic Surveying Using Spectral Analysis of Surface Waves (SSW) Technology.

DTIC Science & Technology

1993-12-01

mnwwrowl «rlpl« Flar* Ijrp«. Longth 8.3 ft V« lgbt 1 lb. Signal Duration 7 soo. Figure 2.21 Aerial Penetrometer (Molineux 1955) 58 springs, for...Preliminary testing showed that the penetration rod which carried the weight of the piston apparatus did not move. The movement came from the air piston...inclined gripper teeth set inside a narrow barrel that allowed penetration in one direction but locked tight against the rod if movement occurred in

Evaluation of Cone Penetrometer Testing (CPT) for Use with Transportation Projects Phase 1

DOT National Transportation Integrated Search

2008-07-01

The ODOT Office of Geotechnical Engineering (OGE) currently uses conventional drilling methods (e.g., hollow stem auger, solid stem auger) to perform subsurface investigations in unconsolidated materials. These techniques have been used for decades a...

DEMONSTRATION BULLETIN: RAPID OPTICAL SCREEN TOOL (ROST™) - LORAL CORPORATION

EPA Science Inventory

The Loral Rapid Optical Screen Tool (ROST™) is a tunable dye laser system used for the detection of petroleum, semi-volatile, and some volatile organic compounds in soils. The technology is used in conjunction with a cone penetrometer (CP).

Characterization of undrained shear strength profiles for soft clays at six sites in Texas.

DOT National Transportation Integrated Search

2009-01-01

TxDOT frequently uses Texas Cone Penetrometer (TCP) blow counts to estimate undrained shear strength. : However, the current correlations between TCP resistance and undrained shear strength have been developed primarily for : significantly stronger s...

Strength Property Estimation for Dry, Cohesionless Soils Using the Military Cone Penetrometer

DTIC Science & Technology

1992-05-01

by Meier and Baladi (1988). Their methodology is based on a theoretical formulation of the CI problem using cavity expansion theory to relate cone... Baladi (1981), incorporates three mechanical properties (cohesion, fric- tion angle, and shear modulus) and the total unit weight. Obviously, these four...unknown soil propertieE cannot be back-calculated directly from a single CI measurement. To ameliorate this problem, Meier and Baladi estimate the total

Static penetration resistance of soils

NASA Technical Reports Server (NTRS)

Durgunoglu, H. T.; Mitchell, J. K.

1973-01-01

Model test results were used to define the failure mechanism associated with the static penetration resistance of cohesionless and low-cohesion soils. Knowledge of this mechanism has permitted the development of a new analytical method for calculating the ultimate penetration resistance which explicitly accounts for penetrometer base apex angle and roughness, soil friction angle, and the ratio of penetration depth to base width. Curves relating the bearing capacity factors to the soil friction angle are presented for failure in general shear. Strength parameters and penetrometer interaction properties of a fine sand were determined and used as the basis for prediction of the penetration resistance encountered by wedge, cone, and flat-ended penetrometers of different surface roughness using the proposed analytical method. Because of the close agreement between predicted values and values measured in laboratory tests, it appears possible to deduce in-situ soil strength parameters and their variation with depth from the results of static penetration tests.

Cone penetrometer equipped with piezoelectric sensors for measurement of soil stiffness in highway pavement.

DOT National Transportation Integrated Search

2005-11-01

The stiffness (elastic modulus and shear modulus) and Poisson's ratio of the base and sublayers are important parameters in the design and quality assurance during construction of highway pavements. The new highway construction guide proposed by AASH...

LASER FLUORESCENCE EEM PROBE FOR CONE PENETROMETER POLLUTION ANALYSIS

EPA Science Inventory

A fiber optic LIF (Laser induced fluorescence) EEM (Excitation emission matrix) instrument for CPT deployment has been successfully developed and field tested. The system employs a Nd: YAG laser and Raman shifter as a rugged field portable excitation source. This excitation sou...

Assessing environmental risk of the retired filter bed area, Battelle West Jefferson

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, S.F.; Thompson, M.D.; Glennon, M.A.

1997-04-01

Initial investigations conducted by the U.S. Department of Energy, Chicago Operations Office, and by Argonne National Laboratory used seismic refraction profiling, electrical resistivity depth sounding, conductivity profiling, magnetic gradiometry, and ground-penetrating radar to study environmental geophysics in the area of the Battelle West Jefferson site`s radiologically contaminated retired filter beds. The investigators used a combination of nonintrusive technologies and innovative drilling techniques to assess environmental risk at the filter beds and to improve understanding of the geology of the Big Darby Creek floodplain. The geophysical investigation, which showed that the preferred groundwater pathway is associated with a laterally extensive depositmore » of silty sand to sand that is less than 12 ft deep in the floodplain area, also guided the location of cone penetrometer test sites and piezometer installation. Cone penetrometer testing was useful for comparing continuous logging data with surface geophysical data in establishing correlations among unconsolidated materials.« less

Development of a Computerized Penetrometer System for Hazardous Waste Site Soils Investigations

DTIC Science & Technology

1988-08-30

soil to prevent contaminant movement . o To preserve the standard electric cone geometry, i.e., 600 point, 1.4-in. (3.56-cm) OD, 1.54-in. 2 (9.9-cm2...considerable soil movements without cracking or rupturing. The second objective was to preserve the ASTM standard electric cone exterior geometry so as to...electrokinesis, and telluric current phenomena. Of these, the electrochemical and electrokinesis phenomena typically produce the largest voltage magnitude (on

Cone penetrometer equipped with piezoelectric sensors for measurement of soil stiffness in highway pavement : executive summary report.

DOT National Transportation Integrated Search

2005-11-01

The stiffness (elastic modulus and shear modulus) and Poissons ratio of the base and : sublayers are important parameters in the design and quality assurance during construction of : highway pavements. During and after the construction of a paveme...

THE ARS-MISSOURI SOIL STRENGTH PROFILE SENSOR: CURRENT STATUS AND FUTURE PROSPECTS

USDA-ARS?s Scientific Manuscript database

Soil compaction that is induced by tillage and traction is an ongoing concern in crop production, and also has environmental consequences. Although cone penetrometers provide standardized compaction measurements, the pointwise data collected makes it difficult to obtain enough data to represent with...

Implantation of Louisiana Electric Cone Penetrometer System (LECOPS) for design of transportation facilities : executive summary.

DOT National Transportation Integrated Search

1994-03-01

For several decades, the Louisiana Department of Transportation and Development (LDOTD) has been able to rely on an ample supply of labor with appropriate equipment to provide soil design data. Budget cutbacks have forced reduction in personnel and e...

Portable SERS Instrument for Explosives Monitoring

DTIC Science & Technology

2008-01-01

groundwater monitoring from a cone penetrometer (CPT) platform (5) Demonstrate improved capability for discriminating explosives versus colorimetry ...interference, and better discrimination of individual explosives compared to colorimetry • Applicability to virtually any environmental water...chemicals such as nitroaromatics or nitramines. While this makes colorimetry more generally applicable at explosive sites, it also limits the ability to

Use of x-ray fluorescence for in-situ detection of metals

NASA Astrophysics Data System (ADS)

Elam, W. T. E.; Whitlock, Robert R.; Gilfrich, John V.

1995-01-01

X-ray fluorescence (XRF) is a well-established, non-destructive method of determining elemental concentrations at ppm levels in complex samples. It can operate in atmosphere with no sample preparation, and provides accuracies of 1% or better under optimum conditions. This report addresses two sets of issues concerning the use of x-ray fluorescence as a sensor technology for the cone penetrometer, for shipboard waste disposal, or for other in-situ, real- time environmental applications. The first issue concerns the applicability of XRF to these applications, and includes investigation of detection limits and matrix effects. We have evaluated the detection limits and quantitative accuracy of a sensor mock-up for metals in soils under conditions expected in the field. In addition, several novel ways of improving the lower limits of detection to reach the drinking water regulatory limits have been explored. The second issue is the engineering involved with constructing a spectrometer within the 1.75 inch diameter of the penetrometer pipe, which is the most rigorous physical constraint. Only small improvements over current state-of-the-art are required. Additional advantages of XRF are that no radioactive sources or hazardous materials are used in the sensor design, and no reagents or any possible sources of ignition are involved.

Environmental Assessment of Selected Cone Penetrometer Grouts and a Tracer

DTIC Science & Technology

1993-08-01

Bentonite Clay ............ ...................... A2 Attapulgite Clay ................................... A22 Microfine Portland Cement...and the tracer are a. Bentonite clay. b. Attapulgite clay. c. Microfine portland cement. d. Joosten grout (calcium silicate grout). e. Urethane grout. f...Inc., on an attapulgite clay product (trade name: Zeogel). " Microfine portland cement. Information was obtained for two micro- fine portland cements

Alternative Penetrometers to Measure the Near Surface Strength of Soft Seafloor Soils

DTIC Science & Technology

2011-09-30

penetrometer (CPT), standard ball penetrometer (BPT), mini-ball penetrometer (mBPT) and a shear vane ( VST ). The CPT and BPT measure electronically a...The VST records the undrained shear strength of the soil at discreet depths. In addition, Shelby tube samples were collected for triaxial and...benchmark strengths from the VST and triaxial/simple shear tests. Thus far, the VST strengths have compared favorably with the results. Results from the

Precision, accuracy, and efficiency of four tools for measuring soil bulk density or strength.

Treesearch

Richard E. Miller; John Hazard; Steven Howes

2001-01-01

Monitoring soil compaction is time consuming. A desire for speed and lower costs, however, must be balanced with the appropriate precision and accuracy required of the monitoring task. We compared three core samplers and a cone penetrometer for measuring soil compaction after clearcut harvest on a stone-free and a stony soil. Precision (i.e., consistency) of each tool...

Assessment of soil strength variability in a havested loblolly pine plantation in the Piedmont region of Alabama, United States

Treesearch

Emily Carter; Tim McDonald; John Torbert

2000-01-01

Mechanised forest harvest operations are a significant source of soil compaction for which intensive tillage is prescribed to alleviate soil compaction and ensure successful regeneration of planted pine trees. Soil strength is a poiential indicator of compaction status of a harvest tract due to its sensitivity and the ease of data collection with a cone penetrometer,...

Where can cone penetrometer technology be applied? Development of a map of Europe regarding the soil penetrability.

PubMed

Fleischer, Matthias; van Ree, Derk; Leven, Carsten

2014-01-01

Over the past decades, significant efforts have been invested in the development of push-in technology for site characterization and monitoring for geotechnical and environmental purposes and have especially been undertaken in the Netherlands and Germany. These technologies provide the opportunity for faster, cheaper, and collection of more reliable subsurface data. However, to maximize the technology both from a development and implementation point of view, it is necessary to have an overview of the areas suitable for the application of this type of technology. Such an overview is missing and cannot simply be read from existing maps and material. This paper describes the development of a map showing the feasibility or applicability of Direct Push/Cone Penetrometer Technology (DPT/CPT) in Europe which depends on the subsurface and its extremely varying properties throughout Europe. Subsurface penetrability is dependent on a range of factors that have not been mapped directly or can easily be inferred from existing databases, especially the maximum depth reachable would be of interest. Among others, it mainly depends on the geology, the soil mechanical properties, the type of equipment used as well as soil-forming processes. This study starts by looking at different geological databases available at the European scale. Next, a scheme has been developed linking geological properties mapped to geotechnical properties to determine basic penetrability categories. From this, a map of soil penetrability is developed and presented. Validating the output by performing field tests was beyond the scope of this study, but for the country of the Netherlands, this map has been compared against a database containing actual cone penetrometer depth data to look for possible contradictory results that would negate the approach. The map for the largest part of Europe clearly shows that there is a much wider potential for the application of Direct Push Technology than is currently seen. The study also shows that there is a lack of large-scale databases that contain depth-resolved data as well as soil mechanical and physical properties that can be used for engineering purposes in relation to the subsurface.

Dynamic cone penetration tests in granular media: Determination of the tip's dynamic load-penetration curve

NASA Astrophysics Data System (ADS)

Escobar, E.; Benz, M.; Gourvès, R.; Breul, P.

2013-06-01

In this article a two-dimensional discrete numerical model, realized in PFC2D, is presented. This model is used in the dynamic penetration tests in a granular medium. Its objective being the validation of the measurement technique offered by Panda 3® (Benz et al. 2011) which is designed to calculate the tip's load-penetration curve for each impact in the soil where different parameters are used. To do so, we have compared the results obtained by calculation during the impacts to those measured directly in the model of a penetrometer through the installation of the gauges at the cone.

A 40-foot static cone penetrometer

USGS Publications Warehouse

Beard, R.M.; Lee, H.J.

1982-01-01

The Navy needs a lightweight device for testing seafloor soils to sub bottom depths of 12 meters in water depths to 60 meters. To meet this need a quasistatic cone penetration device that uses water jetting to reduce friction on the cone rod has been developed. This device is called the XSP-40. The 5-ton XSP-40 stands 15 meters tall and pushes a standard 5-ton cone into the seafloor. It is remotely controlled with an electronic unit on the deck of the support vessel. All cone outputs are recorded directly as a function of penetration depth with a strip chart recorder. A full suite of gauges is provided. on the electronic unit for monitoring the XSP-40's performance during a test .. About 40 penetration tests have been performed with very good success. The XSP-40 was field tested in Norton Sound, off the west coast of Alaska. The general objective, in addition to evaluation of the device, was to gather geotechnical information on sediments that may be involved in processes potentially hazardous to offshore development. Four example penetration records are presented from gas charged sediment zones and areas near the Yukon River delta. In general it was determined that soil classification from cone data agreed well with classifications from core samples. Relative densities of the silt-sand to sandy-silt soils were usually very high. The significance of these results are discussed with respect to storm wave, liquefaction. It is concluded that the XSP-40 is a durable and reliable piece of equipment capable of achieving penetration beyond that possible when not using the water jet system.

Soil experiment

NASA Technical Reports Server (NTRS)

Hutcheson, Linton; Butler, Todd; Smith, Mike; Cline, Charles; Scruggs, Steve; Zakhia, Nadim

1987-01-01

An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment.

Adaptation of Soil Physical Measurement Techniques for the Delineation of Mud and Lakebed Sediments at Neusiedler See

PubMed Central

Kogelbauer, Ilse; Heine, Erwin; D'Amboise, Christopher; Müllebner, Christoph; Sokol, Wolfgang; Loiskandl, Willibald

2013-01-01

For many water management issues of shallow lakes with non-consolidated sediments hydrographic surveys of the open water area and reed belt areas are required. In the frame of water management strategy for the steppe lake Neusiedler See, located between Austria and Hungary, a hydrographic survey was conducted. In the open water area (water depth ≥1 m) a sediment echosounder was used. To validate these measurements and to distinguish between water, mud, and sediment layers in the shallow lake and reed belt area additional measurements were needed. As no common standard methods are available yet, we developed a measurement system based on two commonly applied soil physical measurement techniques providing reproducible physical values: a capacitive sensor and a cone penetrometer combined with GNSS-positioning enable dynamic measurements of georeferenced vertical water-mud-bedsediments profiles. The system bases on site-specific calibrated sensors and allows instantaneous, in situ measurements. The measurements manifest a sharp water-mud interface by a sudden decline to smaller water content which is a function of the dielectric permittivity. A second decline indicates the transition to compacted mud. That is concurrently the density where the penetrometer starts registering significant penetration resistance. The penetrometer detects shallow lakebed-sediment layers. Within the lake survey this measurement system was successfully tested. PMID:24351626

Preduction of Vehicle Mobility on Large-Scale Soft-Soil Terrain Maps Using Physics-Based Simulation

DTIC Science & Technology

2016-08-02

PREDICTION OF VEHICLE MOBILITY ON LARGE-SCALE SOFT- SOIL TERRAIN MAPS USING PHYSICS-BASED SIMULATION Tamer M. Wasfy, Paramsothy Jayakumar, Dave...NRMM • Objectives • Soft Soils • Review of Physics-Based Soil Models • MBD/DEM Modeling Formulation – Joint & Contact Constraints – DEM Cohesive... Soil Model • Cone Penetrometer Experiment • Vehicle- Soil Model • Vehicle Mobility DOE Procedure • Simulation Results • Concluding Remarks 2UNCLASSIFIED

Two different electrical properties can improve transoceanic cable-route mapping

USGS Publications Warehouse

Wynn, J.; McGinnis, T.

2001-01-01

Induced polarization (IP) measurements made in the marine environment were investigated to map and remotely characterize the top 6-10 meters of the seafloor. The continuous resistivity profiling with cone-penetrometer tests, providing important information to engineers planning transoceanic cable routes, was also described. The IP effect and resistivity were identified as the two electric properties to improve transoceanic cable-route mapping. The measurement of IP and resistivity was found to depend on electrical current.

Characterization of a Louisiana Bay Bottom

NASA Astrophysics Data System (ADS)

Freeman, A. M.; Roberts, H. H.

2016-02-01

This study correlates side-scan sonar and CHIRP water bottom-subbottom acoustic amplitudes with cone penetrometer data to expand the limited understanding of the geotechnical properties of sediments in coastal Louisiana's bays. Standardized analysis procedures were developed to characterize the bay bottom and shallow subsurface of the Sister Lake bay bottom. The CHIRP subbottom acoustic data provide relative amplitude information regarding reflection horizons of the bay bottom and shallow subsurface. An amplitude analysis technique was designed to identify different reflectance regions within the lake from the CHIRP subbottom profile data. This amplitude reflectivity analysis technique provides insight into the relative hardness of the bay bottom and shallow subsurface, useful in identifying areas of erosion versus deposition from storms, as well as areas suitable for cultch plants for state oyster seed grounds, or perhaps other restoration projects. Side-scan and CHIRP amplitude reflectivity results are compared to penetrometer data that quantifies geotechnical properties of surface and near-surface sediments. Initial results indicate distinct penetrometer signatures that characterize different substrate areas including soft bottom, storm-deposited silt-rich sediments, oyster cultch, and natural oyster reef areas. Although amplitude analysis of high resolution acoustic data does not directly quantify the geotechnical properties of bottom sediments, our analysis indicates a close relationship. The analysis procedures developed in this study can be applied in other dynamic coastal environments, "calibrating" the use of synoptic acoustic methods for large-scale water bottom characterization.

Identification of elemental mercury in the subsurface

DOEpatents

Jackson, Dennis G

2015-01-06

An apparatus and process is provided for detecting elemental mercury in soil. A sacrificial electrode of aluminum is inserted below ground to a desired location using direct-push/cone-penetrometer based equipment. The insertion process removes any oxides or previously found mercury from the electrode surface. Any mercury present adjacent the electrode can be detected using a voltmeter which indicates the presence or absence of mercury. Upon repositioning the electrode within the soil, a fresh surface of the aluminum electrode is created allowing additional new measurements.

Proceedings of REMR Workshop on Research Priorities for Drainage System and Relief Well Problems. Repair, Evaluation, Maintenance, and Rehabilitation Research Program

DTIC Science & Technology

1989-07-01

were checked by means of a cone penetrometer. Because of concerns that clogging would occur in the ran- dom zones, a special filter cloth sock was...that surrounded the pipes was dirty Figure 3. Old 24-in. BCCMP from toe drain; perforations are essentially plugged due to incrustation 46 Figure 4...associated deposits of ferric hydroxide have resulted in discolored water, unpalatable taste and odors , and reductions in flow through pipes. Additionally

An Abandoned Cliff in Weald Clay, near Lympne, Kent, England.

DTIC Science & Technology

1984-07-17

determined using the cone- penetrometer method, and the clay fraction (% ɚ,wv m) using the sedimentation method. A total of 27 tests were made to determine...Fig. 0 1). Thus the present site has never been glaciated, but has experienced intense periglacial conditions on several occasions. The following...day S m.s.l. Devensian 10,000 - 70,000 app. Periglacial conditions depressed by up to ca. in south-east England 12 0m. Ipswichian 70,000 - 95,000 app

Use of Site Characterization and Analysis Penetrometer System at the Walnut Creek Watershed, Ames, Iowa

DTIC Science & Technology

1993-08-01

grout is pumped through a central tube in the push rod cable and exits through the probe tip. Retraction grouting (as the rod is withdrawn through the...soil) with a microfine Portland cement grout is normally utilized for all projects; however, subfreezing weather mandated that post - retraction grouting...ELECTRODES (4) P2 RESISTIVITY C2 MODULE GROUTING TUBES (2) 24 IN(61 CM) Grout Injector -- 1.4 IN(3.57 CM) o.D. 0" RINGS GROUTING CONE SLEEVE FRICTION

High aspect ratio, remote controlled pumping assembly

DOEpatents

Brown, Steve B.; Milanovich, Fred P.

1995-01-01

A miniature dual syringe-type pump assembly which has a high aspect ratio and which is remotely controlled, for use such as in a small diameter penetrometer cone or well packer used in water contamination applications. The pump assembly may be used to supply and remove a reagent to a water contamination sensor, for example, and includes a motor, gearhead and motor encoder assembly for turning a drive screw for an actuator which provides pushing on one syringe and pulling on the other syringe for injecting new reagent and withdrawing used reagent from an associated sensor.

Tank 241-AX-104 upper vadose zone cone penetrometer demonstration sampling and analysis plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

FIELD, J.G.

1999-02-02

This sampling and analysis plan (SAP) is the primary document describing field and laboratory activities and requirements for the tank 241-AX-104 upper vadose zone cone penetrometer (CP) demonstration. It is written in accordance with Hanford Tank Initiative Tank 241-AX-104 Upper Vadose Zone Demonstration Data Quality Objective (Banning 1999). This technology demonstration, to be conducted at tank 241-AX-104, is being performed by the Hanford Tanks Initiative (HTI) Project as a part of Tank Waste Remediation System (TWRS) Retrieval Program (EM-30) and the Office of Science and Technology (EM-50) Tanks Focus Area. Sample results obtained as part of this demonstration will providemore » additional information for subsequent revisions to the Retrieval Performance Evaluation (RPE) report (Jacobs 1998). The RPE Report is the result of an evaluation of a single tank farm (AX Tank Farm) used as the basis for demonstrating a methodology for developing the data and analyses necessary to support making tank waste retrieval decisions within the context of tank farm closure requirements. The RPE includes a study of vadose zone contaminant transport mechanisms, including analysis of projected tank leak characteristics, hydrogeologic characteristics of tank farm soils, and the observed distribution of contaminants in the vadose zone in the tank farms. With limited characterization information available, large uncertainties exist as to the nature and extent of contaminants that may exist in the upper vadose zone in the AX Tank Farm. Traditionally, data has been collected from soils in the vadose zone through the installation of boreholes and wells. Soil samples are collected as the bore hole is advanced and samples are screened on site and/or sent to a laboratory for analysis. Some in-situ geophysical methods of contaminant analysis can be used to evaluate radionuclide levels in the soils adjacent to an existing borehole. However, geophysical methods require compensation for well casing interference and soil moisture content and may not be successful in some conditions. In some cases the level of interference must be estimated due to uncertainties regarding the materials used in well construction and soil conditions, Well casing deployment used for many in-situ geophysical methods is relatively expensive and geophysical methods do not generally provide real time values for contaminants. In addition, some of these methods are not practical within the boundaries of the tank farm due to physical constraints, such as underground piping and other hardware. The CP technologies could facilitate future characterization of vadose zone soils by providing vadose zone data in near real-time, reducing the number of soil samples and boreholes required, and reducing characterization costs.« less

Use of borehole geophysical logs for improved site characterization at Naval Weapons Industrial Reserve Plant, Dallas, Texas

USGS Publications Warehouse

Anaya, Roberto; Braun, Christopher L.; Kuniansky, Eve L.

2000-01-01

A shallow alluvial aquifer at the Naval Weapons Industrial Reserve Plant near Dallas, Texas, has been contaminated by organic solvents used in the fabrication and assembly of aircraft and aircraft parts. Natural gamma-ray and electromagnetic-induction log data collected during 1997 from 162 wells were integrated with existing lithologic and cone-penetrometer test log data to improve characterization of the subsurface alluvium at the site. The alluvium, consisting of mostly fine-grained, low-permeability sediments, was classified into low, intermediate, and high clay-content sediments on the basis of the gamma-ray logs. Low clay-content sediments were interpreted as being relatively permeable, whereas high clay-content sediments were interpreted as being relatively impermeable. Gamma-ray logs, cone-penetrometer test logs, and electromagnetic-induction logs were used to develop a series of intersecting sections to delineate the spatial distribution of low, intermediate, and high clay-content sediments and to delineate zones of potentially contaminated sediments. The sections indicate three major sedimentary units in the shallow alluvial aquifer at NWIRP. The lower unit consists of relatively permeable, low clay-content sediments and is absent over the southeastern and northwestern part of the site. Permeable zones in the complex, discontinuous middle unit are present mostly in the western part of the site. In the eastern and southeastern part of the site, the upper unit has been eroded away and replaced by fill material. Zones of potentially contaminated sediments are generally within the uppermost clay layer or fill material. In addition, the zones tend to be local occurrences.

High aspect ratio, remote controlled pumping assembly

DOEpatents

Brown, S.B.; Milanovich, F.P.

1995-11-14

A miniature dual syringe-type pump assembly is described which has a high aspect ratio and which is remotely controlled, for use such as in a small diameter penetrometer cone or well packer used in water contamination applications. The pump assembly may be used to supply and remove a reagent to a water contamination sensor, for example, and includes a motor, gearhead and motor encoder assembly for turning a drive screw for an actuator which provides pushing on one syringe and pulling on the other syringe for injecting new reagent and withdrawing used reagent from an associated sensor. 4 figs.

An evaluation of the utility of four in situ test methods for transmission line foundation design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mullen, W.G. Jr.

1991-01-01

This research examines four existing in-situ soil strength testing methods; standard penetration test (SPT), the cone penetrometer (CPT), the flat plate dilatometer (DMT), and the pressuremeter (PMT). Soils data were collected at eight separate sites using each of the devices. The test sites were chosen to mirror soil conditions encountered within the service territory of Virginia Power, the project sponsor. A total of 19 standard soil borings, 30 cone penetrometer soundings, 26 dilatometer soundings, and 33 pressuremeter tests were undertaken in residual, alluvial and marine clay soil conditions. The testing program was conducted with five areas of concern: (1) comparisonmore » of the penetration/stiffness data from the four tests, (2) comparison of values of undrained shear strength and angle of internal friction developed from each of the test methods, (3) determination if pressuremeter data can be correlated to and thereby developed from one of the more rapid tests, (4) comparison of indirect soil type identifications from the standard borings, (5) development of information on the relative effort required for each test. Comparison of the penetration resistance stiffness data produced useful correlations among the CPT and DMT, with the SPT data yielding more erratic results. Shear strength data was most consistent for the marine clay sites, while the CPT and DMT returned useful friction angle data in the alluvial sands. PMT data correlated well to both the CPT and DMT test results. Correlation of PMT results to the SPT was more erratic. Indirect soil identification from the CPT and DMT was fully adequate for transmission line foundation design purposes, and finally, useful comparative data on the relative testing time required for the four in-situ tests was developed.« less

Tunable infrared laser detection of pyrolysis products of explosives in soils

NASA Astrophysics Data System (ADS)

Wormhoudt, J.; Shorter, J. H.; McManus, J. B.; Kebabian, P. L.; Zahniser, M. S.; Kolb, Charles E.; Davis, W. M.; Cespedes, E. R.

1996-07-01

A research program involving two applications of tunable infrared laser differential absorption spectroscopy (TILDAS) with multipass, long-path absorption cells to the detection of explosives contamination in soils is reported. In the first application, sensitive, specific real-time species concentration measurements by TILDAS have led to new understanding of the processes involved in explosives detection by the heating of contaminated soils and the quantification of the resulting pyrolysis gases. In the second, we present results of our calculations of the properties of astigmatic off-axis resonator absorption cells, which show that useful TILDAS path lengths can be achieved inside a cone penetrometer probe.

Extendable mast used in one shot soil penetrometer

NASA Technical Reports Server (NTRS)

Hotz, G. M.; Howard, G. A.

1966-01-01

Penetrometer to test soil characteristics has a piercing head with soil instrumentation equipment attached to an expandable mast actuated by compressed air. The penetrometer gives continuous measurements as the mast pushes the piercing head through the soil.

Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data

USGS Publications Warehouse

Volti, Theodora; Burbidge, David; Collins, Clive; Asten, Michael W.; Odum, Jackson K.; Stephenson, William J.; Pascal, Chris; Holzschuh, Josef

2016-01-01

Although the time‐averaged shear‐wave velocity down to 30 m depth (VS30) can be a proxy for estimating earthquake ground‐motion amplification, significant controversy exists about its limitations when used as a single parameter for the prediction of amplification. To examine this question in absence of relevant strong‐motion records, we use a range of different methods to measure the shear‐wave velocity profiles and the resulting theoretical site amplification factors (AFs) for 30 sites in the Newcastle area, Australia, in a series of blind comparison studies. The multimethod approach used here combines past seismic cone penetrometer and spectral analysis of surface‐wave data, with newly acquired horizontal‐to‐vertical spectral ratio, passive‐source surface‐wave spatial autocorrelation (SPAC), refraction microtremor (ReMi), and multichannel analysis of surface‐wave data. The various measurement techniques predicted a range of different AFs. The SPAC and ReMi techniques have the smallest overall deviation from the median AF for the majority of sites. We show that VS30 can be related to spectral response above a period T of 0.5 s but not necessarily with the maximum amplification according to the modeling done based on the measured shear‐wave velocity profiles. Both VS30 and AF values are influenced by the velocity ratio between bedrock and overlying sediments and the presence of surficial thin low‐velocity layers (<2  m thick and <150  m/s), but the velocity ratio is what mostly affects the AF. At 0.20.5  s do the amplification curves consistently show higher values for soft site classes and lower for hard classes.

A Geostatistical Toolset for Reconstructing Louisiana's Coastal Stratigraphy using Subsurface Boring and Cone Penetrometer Test Data

NASA Astrophysics Data System (ADS)

Li, A.; Tsai, F. T. C.; Jafari, N.; Chen, Q. J.; Bentley, S. J.

2017-12-01

A vast area of river deltaic wetlands stretches across southern Louisiana coast. The wetlands are suffering from a high rate of land loss, which increasingly threats coastal community and energy infrastructure. A regional stratigraphic framework of the delta plain is now imperative to answer scientific questions (such as how the delta plain grows and decays?) and to provide information to coastal protection and restoration projects (such as marsh creation and construction of levees and floodwalls). Through years, subsurface investigations in Louisiana have been conducted by state and federal agencies (Louisiana Department of Natural Resources, United States Geological Survey, United States Army Corps of Engineers, etc.), research institutes (Louisiana Geological Survey, LSU Coastal Studies Institute, etc.), engineering firms, and oil-gas companies. This has resulted in the availability of various types of data, including geological, geotechnical, and geophysical data. However, it is challenging to integrate different types of data and construct three-dimensional stratigraphy models in regional scale. In this study, a set of geostatistical methods were used to tackle this problem. An ordinary kriging method was used to regionalize continuous data, such as grain size, water content, liquid limit, plasticity index, and cone penetrometer tests (CPTs). Indicator kriging and multiple indicator kriging methods were used to regionalize categorized data, such as soil classification. A compositional kriging method was used to regionalize compositional data, such as soil composition (fractions of sand, silt and clay). Stratigraphy models were constructed for three cases in the coastal zone: (1) Inner Harbor Navigation Canal (IHNC) area: soil classification and soil behavior type (SBT) stratigraphies were constructed using ordinary kriging; (2) Middle Barataria Bay area: a soil classification stratigraphy was constructed using multiple indicator kriging; (3) Lower Barataria Bay and Lower Breton Sound areas: a soil texture stratigraphy was constructed using soil compositional data and compositional kriging. Cross sections were extracted from the three-dimensional stratigraphy models to reveal spatial distributions of different stratigraphic features.

Miscellaneous chemical basin expedited site characterization report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riha, B.D.; Pemberton, B.E.; Rossabi, J.

1996-12-01

A total of twenty nine cone penetrometer test (CPT) pushes in three weeks were conducted for vadose zone characterization of the Miscellaneous Chemical Basin (MCB) waste unit at the Savannah River Site. The shallow, unlined basin received liquid chemical wastes over an 18 year period beginning in 1956. This characterization was initiated to determine the vertical and lateral extent of contamination in the vadose zone and to install vadose zone wells for remediation by barometric pumping or active vapor extraction to help prevent further contamination of groundwater. The CPT locations within the waste site were selected based on results frommore » previous shallow soil gas surveys, groundwater contamination data, and the suspected basin center. Geophysical data and soil gas samples were collected at twenty five locations and twenty five vadose zone wells were installed. The wells were screened to target the clay zones and areas of higher soil gas concentrations. The well construction diagrams are provided in Appendix B. Baro-Ball{trademark} valves for enhanced barometric pumping were installed on each well upon completion to immediately begin the remediation treatability study at the site.« less

Technology development plan: Geotechnical survey systems for OTEC (Ocean Thermal Energy Conversion) cold water pipes

NASA Astrophysics Data System (ADS)

Valent, Philip J.; Riggins, Michael

1989-04-01

An overview is given of current and developing technologies and techniques for performing geotechnical investigations for siting and designing Cold Water Pipes (CWP) for shelf-resting Ocean Thermal Energy Conversion (OTEC) power plants. The geotechnical in situ tools used to measure the required parameters and the equipment/systems used to deploy these tools are identified. The capabilities of these geotechnical tools and deployment systems are compared to the data requirements for the CWP foundation/anchor design, and shortfalls are identified. For the last phase of geotechnical data gathering for design, a drillship will be required to perform soil boring work, to obtain required high quality sediment samples for laboratory dynamic testing, and to perform deep penetration in situ tests. To remedy shortfalls and to reduce the future OTEC CWP geotechnical survey costs, it is recommended that a seafloor resting machine be developed to advance the friction cone penetrometer, and also probably a pressuremeter, to provide geotechnical parameters to shallow subseafloor penetrations on slopes of 35 deg and in water depths to 1300 m.

Design of a soil cutting resistance sensor for application in site-specific tillage.

PubMed

Agüera, Juan; Carballido, Jacob; Gil, Jesús; Gliever, Chris J; Perez-Ruiz, Manuel

2013-05-10

One objective of precision agriculture is to provide accurate information about soil and crop properties to optimize the management of agricultural inputs to meet site-specific needs. This paper describes the development of a sensor equipped with RTK-GPS technology that continuously and efficiently measures soil cutting resistance at various depths while traversing the field. Laboratory and preliminary field tests verified the accuracy of this prototype soil strength sensor. The data obtained using a hand-operated soil cone penetrometer was used to evaluate this field soil compaction depth profile sensor. To date, this sensor has only been tested in one field under one gravimetric water content condition. This field test revealed that the relationships between the soil strength profile sensor (SSPS) cutting force and soil cone index values are assumed to be quadratic for the various depths considered: 0-10, 10-20 and 20-30 cm (r2 = 0.58, 0.45 and 0.54, respectively). Soil resistance contour maps illustrated its practical value. The developed sensor provides accurate, timely and affordable information on soil properties to optimize resources and improve agricultural economy.

Mathematical characterization of mechanical behavior of porous frictional granular media

NASA Technical Reports Server (NTRS)

Chung, T. J.; Lee, J. K.

1972-01-01

A new definition of loading and unloading along the yield surface of Roscoe and Burland is introduced. This is achieved by noting that the strain-hardening parameter in the plastic potential function is deduced from the yield locus equation of Roscoe and Burland. The analytical results are compared with the experimental results for plate-bearing and cone-penetrometer problems and close agreements are demonstrated. The wheel-soil interaction is studied under dynamic loading. The rate-dependent plasticity or viscoelastoplastic behavior is considered. This is accomplished by the internal (hidden) variables associated with time-dependent viscous properties directly superimposed with inelastic behavior governed by the yield criteria of Roscoe and Burland. Effects of inertia and energy dissipation are properly accounted for. Example problems are presented.

Evaluation of subsurface exploration, sampling, and water-quality-analysis methods at an abandoned wood-preserving plant site at Jackson, Tennessee

USGS Publications Warehouse

Parks, W.S.; Carmichael, J.K.; Mirecki, J.E.

1993-01-01

Direct Push Technology (DPT) and a modified-auger method of sampling were used at an abandoned wood-preserving plant site at Jackson, Tennessee, to collect lithologic data and ground-water samples in an area known to be affected by a subsurface creosote plume. The groundwater samples were analyzed using (1) gas chromatography with photo-ionization detection (GS/PID), (2) high- performance liquid chromatography (HPLC), (3) colonmetric phenol analysis, and (4) toxicity bioassay. DPT piezocone and cone-penetrometer-type tools provided lithologic data and ground-water samples at two onsite stations to a depth of refusal of about 35 feet below land surface. With the assistance of an auger rig, this depth was extended to about 65 feet by pushing the tools in advance of the augers. Following the DPT work, a modified-auger method was tested by the USGS. This method left doubt as to the integrity of the samples collected once zones of contamination were penetrated. GC/PID and HPLC methods of water-quality analysis provided the most data concerning contaminants in the ground-water and proved to be the most effective in creosote plume detection. Analyses from these methods showed that the highest concentrations of contaminants were detected at depths less than about 35 feet below land surface. Phenol analyses provided data supplemental to the HPLC analyses. Bioassay data indicated that toxicity associated with the plume extended to depths of about 55 feet below land surface.

Modelling and interpreting biologically crusted dryland soil sub-surface structure using automated micropenetrometry

NASA Astrophysics Data System (ADS)

Hoon, Stephen R.; Felde, Vincent J. M. N. L.; Drahorad, Sylvie L.; Felix-Henningsen, Peter

2015-04-01

Soil penetrometers are used routinely to determine the shear strength of soils and deformable sediments both at the surface and throughout a depth profile in disciplines as diverse as soil science, agriculture, geoengineering and alpine avalanche-safety (e.g. Grunwald et al. 2001, Van Herwijnen et al. 2009). Generically, penetrometers comprise two principal components: An advancing probe, and a transducer; the latter to measure the pressure or force required to cause the probe to penetrate or advance through the soil or sediment. The force transducer employed to determine the pressure can range, for example, from a simple mechanical spring gauge to an automatically data-logged electronic transducer. Automated computer control of the penetrometer step size and probe advance rate enables precise measurements to be made down to a resolution of 10's of microns, (e.g. the automated electronic micropenetrometer (EMP) described by Drahorad 2012). Here we discuss the determination, modelling and interpretation of biologically crusted dryland soil sub-surface structures using automated micropenetrometry. We outline a model enabling the interpretation of depth dependent penetration resistance (PR) profiles and their spatial differentials using the model equations, σ {}(z) ={}σ c0{}+Σ 1n[σ n{}(z){}+anz + bnz2] and dσ /dz = Σ 1n[dσ n(z) /dz{} {}+{}Frn(z)] where σ c0 and σ n are the plastic deformation stresses for the surface and nth soil structure (e.g. soil crust, layer, horizon or void) respectively, and Frn(z)dz is the frictional work done per unit volume by sliding the penetrometer rod an incremental distance, dz, through the nth layer. Both σ n(z) and Frn(z) are related to soil structure. They determine the form of σ {}(z){} measured by the EMP transducer. The model enables pores (regions of zero deformation stress) to be distinguished from changes in layer structure or probe friction. We have applied this method to both artificial calibration soils in the laboratory, and in-situ field studies. In particular, we discuss the nature and detection of surface and buried (fossil) subsurface Biological Soil Crusts (BSCs), voids, macroscopic particles and compositional layers. The strength of surface BSCs and the occurrence of buried BSCs and layers has been detected at sub millimetre scales to depths of 40mm. Our measurements and field observations of PR show the importance of morphological layering to overall BSC functions (Felde et al. 2015). We also discuss the effect of penetrometer shaft and probe-tip profiles upon the theoretical and experimental curves, EMP resolution and reproducibility, demonstrating how the model enables voids, buried biological soil crusts, exotic particles, soil horizons and layers to be distinguished one from another. This represents a potentially important contribution to advancing understanding of the relationship between BSCs and dryland soil structure. References: Drahorad SL, Felix-Henningsen P. (2012) An electronic micropenetrometer (EMP) for field measurements of biological soil crust stability, J. Plant Nutr. Soil Sci., 175, 519-520 Felde V.J.M.N.L., Drahorad S.L., Felix-Henningsen P., Hoon S.R. (2015) Ongoing oversanding induces biological soil crust layering - a new approach for BSC structure elucidation determined from high resolution penetration resistance data (submitted) Grunwald, S., Rooney D.J., McSweeney K., Lowery B. (2001) Development of pedotransfer functions for a profile cone penetrometer, Geoderma, 100, 25-47 Van Herwijnen A., Bellaire S., Schweizer J. (2009) Comparison of micro-structural snowpack parameters derived from penetration resistance measurements with fracture character observations from compression tests, Cold Regions Sci. {& Technol.}, 59, 193-201

Cone-penetrometer exploration of sinkholes: Stratigraphy and soil properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bloomberg, D.; Upchurch, S.B.; Hayden, M.L.

1988-10-01

Four sinkholes with varying surficial expressions were subjected to detailed stratigraphic and soil analysis by means of Standard Penetration Tests (SPT) and Electric Friction Cone Penetration Tests (CPT) in order to evaluate applications of CPT to sinkhole investigations. Although widely used, SPT data are of limited value and difficult to apply to sinkhole mapping. CPT is sensitive to minor lithologic variability and is superior to SPT as a cost-effective technique for determining geotechnical properties of sinkholes. The effectiveness of CPT data results from the force measurements made along the sleeve of the cone. The friction ratio (ratio of sleeve tomore » tip resistance) is a good indicator of soil stratigraphy and properties. By smoothing the friction-ratio data, general stratigraphy and changes in soil properties are easily identified. Stratigraphy of the sinks has been complicated by intense weathering, karstification and marine transgressions. The resulting deposits include five stratigraphic units. 1 and 2 represent Plio-Pleistocene marine sediments with Unit 2 being the zone of soil clay accumulation. 3 and 4 are horizons residual from Miocene strata and indicate an episode of karstification prior to deposition of Units 1 and 2. CPT provides sufficient information for recognition of sinkhole stratigraphy and geotechnical properties. When coupled with laboratory soil analysis, CPT provides unique information about sinkhole geometry and dynamics. In contrast, SPT indicates general, inconclusive trends.« less

Layer detection and snowpack stratigraphy characterisation from digital penetrometer signals

NASA Astrophysics Data System (ADS)

Floyer, James Antony

Forecasting for slab avalanches benefits from precise measurements of snow stratigraphy. Snow penetrometers offer the possibility of providing detailed information about snowpack structure; however, their use has yet to be adopted by avalanche forecasting operations in Canada. A manually driven, variable rate force-resistance penetrometer is tested for its ability to measure snowpack information suitable for avalanche forecasting and for spatial variability studies on snowpack properties. Subsequent to modifications, weak layers of 5 mm thick are reliably detected from the penetrometer signals. Rate effects are investigated and found to be insignificant for push velocities between 0.5 to 100 cm s-1 for dry snow. An analysis of snow deformation below the penetrometer tip is presented using particle image velocimetry and two zones associated with particle deflection are identified. The compacted zone is a region of densified snow that is pushed ahead of the penetrometer tip; the deformation zone is a broader zone surrounding the compacted zone, where deformation is in compression and in shear. Initial formation of the compacted zone is responsible for pronounced force spikes in the penetrometer signal. A layer tracing algorithm for tracing weak layers, crusts and interfaces across transects or grids of penetrometer profiles is presented. This algorithm uses Wiener spiking deconvolution to detect a portion of the signal manually identified as a layer in one profile across to an adjacent profile. Layer tracing is found to be most effective for tracing crusts and prominent weak layers, although weak layers close to crusts were not well traced. A framework for extending this method for detecting weak layers with no prior knowledge of weak layer existence is also presented. A study relating the fracture character of layers identified in compression tests is presented. A multivariate model is presented that distinguishes between sudden and other fracture characters 80% of the time. Transects of penetrometer profiles are presented over several alpine terrain features commonly associated with spatial variability of snowpack properties. Physical processes relating to the variability of certain snowpack properties revealed in the transects is discussed. The importance of characteristic signatures for training avalanche practitioners to recognise potentially unstable terrain is also discussed.

Passive Earth Entry Vehicle Landing Test

NASA Technical Reports Server (NTRS)

Kellas, Sotiris

2017-01-01

Two full-scale passive Earth Entry Vehicles (EEV) with realistic structure, surrogate sample container, and surrogate Thermal Protection System (TPS) were built at NASA Langley Research Center (LaRC) and tested at the Utah Test and Training Range (UTTR). The main test objective was to demonstrate structural integrity and investigate possible impact response deviations of the realistic vehicle as compared to rigid penetrometer responses. With the exception of the surrogate TPS and minor structural differences in the back shell construction, the two test vehicles were identical in geometry and both utilized the Integrated Composite Stiffener Structure (ICoSS) structural concept in the forward shell. The ICoSS concept is a lightweight and highly adaptable composite concept developed at NASA LaRC specifically for entry vehicle TPS carrier structures. The instrumented test vehicles were released from a helicopter approximately 400 m above ground. The drop height was selected such that at least 98% of the vehicles terminal velocity would be achieved. While drop tests of spherical penetrometers and a low fidelity aerodynamic EEV model were conducted at UTTR in 1998 and 2000, this was the first time a passive EEV with flight-like structure, surrogate TPS, and sample container was tested at UTTR for the purpose of complete structural system validation. Test results showed that at a landing vertical speed of approximately 30 m/s, the test vehicle maintained structural integrity and enough rigidity to penetrate the sandy clay surface thus attenuating the landing load, as measured at the vehicle CG, to less than 600 g. This measured deceleration was found to be in family with rigid penetrometer test data from the 1998 and 2000 test campaigns. Design implications of vehicle structure/soil interaction with respect to sample container and sample survivability are briefly discussed.

Design of a Soil Cutting Resistance Sensor for Application in Site-Specific Tillage

PubMed Central

Agüera, Juan; Carballido, Jacob; Gil, Jesús; Gliever, Chris J.; Perez-Ruiz, Manuel

2013-01-01

One objective of precision agriculture is to provide accurate information about soil and crop properties to optimize the management of agricultural inputs to meet site-specific needs. This paper describes the development of a sensor equipped with RTK-GPS technology that continuously and efficiently measures soil cutting resistance at various depths while traversing the field. Laboratory and preliminary field tests verified the accuracy of this prototype soil strength sensor. The data obtained using a hand-operated soil cone penetrometer was used to evaluate this field soil compaction depth profile sensor. To date, this sensor has only been tested in one field under one gravimetric water content condition. This field test revealed that the relationships between the soil strength profile sensor (SSPS) cutting force and soil cone index values are assumed to be quadratic for the various depths considered: 0–10, 10–20 and 20–30 cm (r2 = 0.58, 0.45 and 0.54, respectively). Soil resistance contour maps illustrated its practical value. The developed sensor provides accurate, timely and affordable information on soil properties to optimize resources and improve agricultural economy. PMID:23666127

Low Velocity Earth-Penetration Test and Analysis

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jones, Yvonne; Knight, Norman F., Jr.; Kellas, Sotiris

2001-01-01

Modeling and simulation of structural impacts into soil continue to challenge analysts to develop accurate material models and detailed analytical simulations to predict the soil penetration event. This paper discusses finite element modeling of a series of penetrometer drop tests into soft clay. Parametric studies are performed with penetrometers of varying diameters, masses, and impact speeds to a maximum of 45 m/s. Parameters influencing the simulation such as the contact penalty factor and the material model representing the soil are also studied. An empirical relationship between key parameters is developed and is shown to correlate experimental and analytical results quite well. The results provide preliminary design guidelines for Earth impact that may be useful for future space exploration sample return missions.

Situ soil sampling probe system with heated transfer line

DOEpatents

Robbat, Jr., Albert

2002-01-01

The present invention is directed both to an improved in situ penetrometer probe and to a heated, flexible transfer line. The line and probe may be implemented together in a penetrometer system in which the transfer line is used to connect the probe to a collector/analyzer at the surface. The probe comprises a heater that controls a temperature of a geologic medium surrounding the probe. At least one carrier gas port and vapor collection port are located on an external side wall of the probe. The carrier gas port provides a carrier gas into the geologic medium, and the collection port captures vapors from the geologic medium for analysis. In the transfer line, a flexible collection line that conveys a collected fluid, i.e., vapor, sample to a collector/analyzer. A flexible carrier gas line conveys a carrier gas to facilitate the collection of the sample. A system heating the collection line is also provided. Preferably the collection line is electrically conductive so that an electrical power source can generate a current through it so that the internal resistance generates heat.

Comparison of Shear-wave Profiles for a Compacted Fill in a Geotechnical Test Pit

NASA Astrophysics Data System (ADS)

Sylvain, M. B.; Pando, M. A.; Whelan, M.; Bents, D.; Park, C.; Ogunro, V.

2014-12-01

This paper investigates the use of common methods for geological seismic site characterization including: i) multichannel analysis of surface waves (MASW),ii) crosshole seismic surveys, and iii) seismic cone penetrometer tests. The in-situ tests were performed in a geotechnical test pit located at the University of North Carolina at Charlotte High Bay Laboratory. The test pit has dimensions of 12 feet wide by 12 feet long by 10 feet deep. The pit was filled with a silty sand (SW-SM) soil, which was compacted in lifts using a vibratory plate compactor. The shear wave velocity values from the 3 techniques are compared in terms of magnitude versus depth as well as spatially. The comparison was carried out before and after inducing soil disturbance at controlled locations to evaluate which methods were better suited to captured the induced soil disturbance.

Indentation of a free-falling lance penetrometer into a poroelastic seabed

NASA Astrophysics Data System (ADS)

Elsworth, Derek; Lee, Dae Sung

2005-02-01

A solution is developed for the build-up, steady and post-arrest dissipative pore fluid pressure fields that develop around a blunt penetrometer that self-embeds from freefall into the seabed. Arrest from freefall considers deceleration under undrained conditions in a purely cohesive soil, with constant shear strength with depth. The resulting decelerating velocity field is controlled by soil strength, geometric bearing capacity factors, and inertial components. At low impact velocities the embedment process is controlled by soil strength, and at high velocities by inertia. With the deceleration defined, a solution is evaluated for a point normal dislocation penetrating in a poroelastic medium with a prescribed decelerating velocity. Dynamic steady pressures, PD, develop relative to the penetrating tip geometry with their distribution conditioned by the non-dimensional penetration rate, UD, incorporating impacting penetration rate, consolidation coefficient and penetrometer radius, and the non-dimensional strength, ND, additionally incorporating undrained shear strength of the sediment. Pore pressures develop to a steady peak magnitude at the penetrometer tip, and drop as PD=1/xD with distance xD behind the tip and along the shaft. Peak induced pressure magnitudes may be correlated with sediment permeabilities, post-arrest dissipation rates may be correlated with consolidation coefficients, and depths of penetration may be correlated with shear strengths. Together, these records enable strength and transport parameters to be recovered from lance penetrometer data. Penetrometer data recorded off La Palma in the Canary Islands (J. Volcanol. Geotherm. Res. 2000; 101:253) are used to recover permeabilities and consolidation coefficients from peak pressure and dissipation response, respectively. Copyright

Mountain bike trail compaction relation to selected physical parameters

Treesearch

Jeff Hale; Rodney R. Zwick

2002-01-01

The purpose of this research is to explore the rates of compaction and their relation to trail contextual aspects of: soil type, slope and crown cover on a newly established mountain bike trail in the northern reach of Vermont. A random sample of 52 sites was selected for monitoring on the 1.09-mile trail. Three penetrometer readings were taken at each of the sample...

DEMONSTRATION BULLETIN: SITE CHARACTERIZATION ANALYSIS PENETROMETER SYSTEM (SCAPS) LIF SENSOR - U.S. ARMY, NAVY, AND AIR FORCE (TRI-SERVICES)

EPA Science Inventory

The Tri-Services Site Characterization Analysis Penetrometer System (SCAPS) was developed by the U.S. Army (U.S. Army Corps of Engineers, Waterways Experiment Station [WES] and the Army Environmental Center [AEC]), Navy (Naval Command, Control and Ocean Surveillance Center), and ...

Integrated monitoring and assessment of soil restoration treatments in the Lake Tahoe Basin.

PubMed

Grismer, M E; Schnurrenberger, C; Arst, R; Hogan, M P

2009-03-01

Revegetation and soil restoration efforts, often associated with erosion control measures on disturbed soils, are rarely monitored or otherwise evaluated in terms of improved hydrologic, much less, ecologic function and longer term sustainability. As in many watersheds, sediment is a key parameter of concern in the Tahoe Basin, particularly fine sediments less than about ten microns. Numerous erosion control measures deployed in the Basin during the past several decades have under-performed, or simply failed after a few years and new soil restoration methods of erosion control are under investigation. We outline a comprehensive, integrated field-based evaluation and assessment of the hydrologic function associated with these soil restoration methods with the hypothesis that restoration of sustainable function will result in longer term erosion control benefits than that currently achieved with more commonly used surface treatment methods (e.g. straw/mulch covers and hydroseeding). The monitoring includes cover-point and ocular assessments of plant cover, species type and diversity; soil sampling for nutrient status; rainfall simulation measurement of infiltration and runoff rates; cone penetrometer measurements of soil compaction and thickness of mulch layer depths. Through multi-year hydrologic and vegetation monitoring at ten sites and 120 plots, we illustrate the results obtained from the integrated monitoring program and describe how it might guide future restoration efforts and monitoring assessments.

Soil mechanics

NASA Technical Reports Server (NTRS)

Mitchell, J. K.; Carrier, W. D., III; Houston, W. N.; Scott, R. F.; Bromwell, L. G.; Durgunoglu, H. T.; Hovland, H. J.; Treadwell, D. D.; Costes, N. C.

1972-01-01

Preliminary results are presented of an investigation of the physical and mechanical properties of lunar soil on the Descartes slopes, and the Cayley Plains in the vicinity of the LM for Apollo 16. The soil mechanics data were derived form (1) crew commentary and debriefings, (2) television, (3) lunar surface photography, (4) performance data and observations of interactions between soil and lunar roving vehicle, (5) drive-tube and deep drill samples, (6) sample characteristics, and (7) measurements using the SRP. The general characteristics, stratigraphy and variability are described along with the core samples, penetrometer test results, density, porosity and strength.

Geologic, water-chemistry, and hydrologic data from multiple-well monitoring sites and selected water-supply wells in the Santa Clara Valley, California, 1999-2003

USGS Publications Warehouse

Newhouse, M.W.; Hanson, R.T.; Wentworth, C.M.; Everett, Rhett; Williams, C.F.; Tinsley, J.C.; Noce, T.E.; Carkin, B.A.

2004-01-01

To better identify the three-dimensional geohydrologic framework of the Santa Clara Valley, lithologic, geologic, geophysical, geomechanical, hydraulic, and water-chemistry data were collected from eight ground-water multiple-well monitoring sites constructed in Santa Clara County, California, as part of a series of cooperative studies between the U.S. Geological Survey and the Santa Clara Valley Water District. The data are being used to update and improve the three-dimensional geohydrologic framework of the basin and to address issues related to water supply, water chemistry, sequence stratigraphy, geology, and geological hazards. This report represents a compilation of data collected from 1999 to 2003, including location and design of the monitoring sites, cone penetrometer borings, geologic logs, lithologic logs, geophysical logs, core analysis, water-chemistry analysis, ground-water-level measurements, and hydraulic and geomechanical properties from wells and core samples. Exploratory cone penetrometer borings taken in the upper 17 to 130 feet at six of the monitoring sites identified the base of Holocene as no deeper than 75 feet in the central confined area and no deeper than 35 feet in the southern unconfined areas of the valley. Generalized lithologic characterization from the monitoring sites indicates about four to six different aquifer units separated by relatively fine-grained units occur within the alluvial deposits shallower than 860 feet deep. Analysis of geophysical logs indicates that coarse-grained units varied in thickness between 10 and 25 feet in the southeastern unconfined area of the valley and between 50 and 200 feet in the south-central and southwestern areas of the valley. Deviations from temperature-gradient logs indicate that the majority of horizontal ground-water flow occurs above a depth of 775 feet in the south central and above 510 feet in the southeastern areas of the valley. Bulk physical properties from more than 1,150 feet of core samples indicate an average primary-wave velocity of about 5,515 feet per second, a bimodal distribution of density between 2.19 and 2.32 grams per cubic centimeter with an average of 2.16 grams per cubic centimeter, and a magnetic susceptibility that generally ranged between 9 and 40 with an average of 22. Water-chemistry data indicate that the ground water in the alluvial aquifers generally is low in total dissolved solids and chloride and of good quality. Isotopic data indicate that water from artificial recharge is present throughout the shallower parts of the aquifer system but may not be present toward the center of the valley. The percentage of water from artificial recharge present in ground water ranges from 0 to 61 percent for water-supply wells. The age of most shallow ground water is less than 2,000 years before present, and the age of deeper ground water is as much as 39,900 years before present, as determined from carbon age dates. Initial water-level data from the multiple-well monitoring sites indicate seasonal water-level fluctuations as great as 60 feet and water-level differences between aquifers as great as 10 feet. The water-level hydrographs indicate different water-level changes and relations between aquifers in different parts of the basin. However, most of these hydrographs indicate the potential for downward water-level gradients, with lower hydraulic heads in the deeper monitoring wells. Hydraulic properties of selected new monitoring wells indicate that horizontal hydraulic conductivities range from 0.1 to 583 feet per day. Hydraulic testing of selected core samples yielded vertical hydraulic conductivity values ranging from 8 x 10-4 to 0.3 feet per day, and effective porosity values ranging from 0.21 to 0.4. Geomechanical properties estimated from one-dimensional consolidation tests of selected core samples resulted in geometric mean inelastic and elastic specific storage values of 1.5 x 10-

The West Beverly Hills Lineament and Beverly Hills High School: Ethical Issues in Geo-Hazard Communication

NASA Astrophysics Data System (ADS)

Gath, Eldon; Gonzalez, Tania; Roe, Joe; Buchiarelli, Philip; Kenny, Miles

2014-05-01

Results of geotechnical studies for the Westside Subway were disclosed in a public hearing on Oct. 19, 2011, showing new "active faults" of the Santa Monica fault and the West Beverly Hills Lineament (WBHL), identified as a northern extension of the Newport-Inglewood fault. Presentations made spoke of the danger posed by these faults, the possibility of killing people, and how it was good news that these faults had been discovered now instead of later. The presentations were live and are now memorialized as YouTube videos, (http://www.youtube.com/watch?v=Omx2BTIpzAk and others). No faults had been physically exposed or observed by the study; the faults were all interpreted from cone penetrometer probes, supplemented by core borings and geophysical transects. Several of the WBHL faults traversed buildings of the Beverly Hills High School (BHHS), triggering the school district to geologically map and characterize these faults for future planning efforts, and to quantify risk to the students in the 1920's high school building. 5 exploratory trenches were excavated within the high school property, 12 cone penetrometers were pushed, and 26-cored borings were drilled. Geologic logging of the trenches and borings and interpretation of the CPT data failed to confirm the presence of the mapped WBHL faults, instead showing an unfaulted, 3° NE dipping sequence of mid-Pleistocene alluvial fan deposits conformably overlying an ~1 Ma marine sand. Using 14C, OSL, and soil pedology for stratigraphic dating, the BHHS site was cleared from fault rupture hazards and the WBHL was shown to be an erosional margin of Benedict Canyon, partially buttressed by 40-200 ka alluvial deposits from Benedict Wash. The consequence of the Westside Subway's active fault maps has been the unexpected expenditure of millions of dollars for emergency fault investigations at BHHS and several other private properties within a densely developed urban highrise environment. None of these studies have found any active faults where they had been interpreted, mapped, and published by the subway's consultants. Litigation is underway by the affected parties to recoup their geological expenditures and recover costs for lost business revenues. Even had the active fault map been correct, its public release was poorly managed. That the released active fault map has now been found to be badly in error poses more significant ethical issues about hazard communication and likely legal consequences.

Impact penetrometry of analogue planetary regoliths

NASA Astrophysics Data System (ADS)

Paton, M. D.; Green, S. F.; Ball, A. J.

2013-09-01

Erosion and deposition processes on major and minor planetary bodies generate layers of loose broken up material on the surface. Due to the long period over which these processes have been active, the material in these layers can be, depending on the bodies' size, finely ground into grains similar in size to sand or a finer power such as found on the lunar surface. The subsurface stratigraphy of an asteroid, for example, could help characterise and understand the variety of geological features and granular processes on asteroids, e.g. see [1]. The microstructural properties of the asteroid's surface are also important for understanding the impact history of the asteroid, the interpretation of light scattering observations and thermal modelling. As the surface of an asteroid or planet will most likely be granular and loose it is then easy to penetrate, for example by using a cylindrical body tipped with a conical or other shaped tip. Such a device, fitted with a force sensor, that measures the resistance to penetration, can then be used to infer the physical properties of the target, in a similar way to penetrometers used on Earth. These instruments can be made small enough to be deployed by spacecraft to investigate extraterrestrial surfaces as with the Huygens penetrometer that investigated the surface of Titan [2]. A prototype impact penetrometer (fig. 1), based on a standard instrument used for making such measurements on Earth, is introduced. For detailed characterisation of the local stratigraphy penetrometry is usually conducted on the Earth using such a standardised penetrometer inserted slowly and at constant speed into the subsurface. Consequently there is an established and extensive library of publications available for the interpretation of this type of instrument. Impact penetrometry, as the name suggests, is conducted during the impact of a projectile. This type of penetrometry has not been so well characterised and interpreting the results, in terms of stratigraphy, is made difficult due to dynamic effects such as variation in friction and drag coefficient with speed. Here we investigate speed-dependent effects with depth of penetration (see fig. 2) and compare them with the effects of layered material (see fig. 3). We combine a microstructural model [3] with a macroscale model of penetration (see fig. 6) to investigate the importance of momentum effects with impact speed and grain size relative to penetrometer size.We assess the penetrometer for detection of microstructural properties of the regolith such as particle size (see fig. 5) and mass and make recommendations, building on our previous work, for further refinement of an asteroid penetrometer.

Prototype of the Modular Equipment Transporter (MET)

NASA Technical Reports Server (NTRS)

1970-01-01

A prototype of the Modular Equipment Transporter (MET), nicknamed the 'Rickshaw' after its shape and method of propulsion. This equipment was used by the Apollo 14 astronauts during their geological and lunar surface simulation training in the Pinacate volcanic area of northwestern Sonora, Mexico. The Apollo 14 crew will be the first one to use the MET. It will be a portable workbench with a place for the lunar handtools and their carrier, three cameras, two sample container bags, a Special Environmental Sample Container, spare film magazines, and a Lunar Surface Penetrometer.

Site characterization and analysis penetrometer system

NASA Astrophysics Data System (ADS)

Heath, Jeff

1995-04-01

The site characterization and analysis penetrometer system (SCAPS) with laser induced fluorescence (LIF) sensors is being demonstrated as a quick field screening technique to determine the physical and chemical characteristics of subsurface soil and contaminants at hazardous waste sites SCAPS is a collaborative development effort of the Navy, Army, and Air Force under the Tri-Service SCAPS Program. The current SCAPS configuration is designed to quickly and cost-effectively distinguish areas contaminated with petroleum products (hydrocarbons) from unaffected areas.

Interpretation of the lime column penetration test

NASA Astrophysics Data System (ADS)

Liyanapathirana, D. S.; Kelly, R. B.

2010-06-01

Dry soil mix (DSM) columns are used to reduce the settlement and to improve the stability of embankments constructed on soft clays. During construction the shear strength of the columns needs to be confirmed for compliance with technical assumptions. A specialized blade shaped penetrometer known as the lime column probe, has been developed for testing DSM columns. This test can be carried out as a pull out resistance test (PORT) or a push in resistance test (PIRT). The test is considered to be more representative of average column shear strength than methods that test only a limited area of the column. Both PORT and PIRT tests require empirical correlations of measured resistance to an absolute measure of shear strength, in a similar manner to the cone penetration test. In this paper, finite element method is used to assess the probe factor, N, for the PORT test. Due to the large soil deformations around the probe, an Arbitrary Lagrangian Eulerian (ALE) based finite element formulation has been used. Variation of N with rigidity index and the friction at the probe-soil interface are investigated to establish a range for the probe factor.

California bearing ratio analysis on Kunduran - Goa Terawangan road, Blora Regency

NASA Astrophysics Data System (ADS)

Lashari, Widodo, Aris; Azizah, Nur

2018-03-01

The study about California Bearing Ratio on subgrade is required as the road infrastructure. Some researchers has conducted studies about California Bearing Ratio in both laboratory and the field to figure out the load bearing capacity of the existing soil in the field. The Kunduran - Goa Terawang road is a regency road which connects the Kunduran district and Todanan district. The length of the Kunduran - Goa Terawang is 11,44 km with the endpoint identifier (STA 0 road) from T intersection 3/49 on the provincial road km 25. The Kunduran - Goa Terawang road has experienced damaged from time to time. Therefore, the condition of load bearing capacity on the subgrade must be analysed. The value of load bearing capacity of the subgrade on the road. The California Bearing Ratio had to be conducted to figure out the value. The California Bearing Ratio test was conducted in two ways, 1) the laboratory California Bearing Ratio testing and the field California Bearing Ration using the Dynamic Cone Penetrometer. The testing was conducted in three points, STA 0+250, STA 0+500, dan STA 0+750.

Soil Penetration Rates by Earthworms and Plant Roots- Mechanical and Energetic Considerations

NASA Astrophysics Data System (ADS)

Ruiz, Siul; Schymanski, Stan; Or, Dani

2016-04-01

We analyze the implications of different soil burrowing rates by earthworms and growing plant roots using mechanical models that consider soil rheological properties. We estimate the energetic requirements for soil elasto-viscoplastic displacement at different rates for similar burrows and water contents. In the core of the mechanical model is a transient cavity expansion into viscoplastic wet soil that mimic an earthworm or root tip cone-like penetration and subsequent cavity expansion due to pressurized earthworm hydrostatic skeleton or root radial growth. Soil matrix viscoplatic considerations enable separation of the respective energetic requirements for earthworms penetrating at 2 μm/s relative to plant roots growing at 0.2 μm/s . Typical mechanical and viscous parameters are obtained inversely for soils under different fixed water contents utilizing custom miniaturized cone penetrometers at different fixed penetration rates (1 to 1000 μm/s). Experimental results determine critical water contents where soil exhibits pronounced viscoplatic behavior (close to saturation), bellow which the soil strength limits earthworms activity and fracture propagation by expanding plant roots becomes the favorable mechanical mode. The soil mechanical parameters in conjunction with earthworm and plant root physiological pressure limitations (200 kPa and 2000 kPa respectively) enable delineation of the role of soil saturation in regulating biotic penetration rates for different soil types under different moisture contents. Furthermore, this study provides a quantitative framework for estimating rates of energy expenditure for soil penetration, which allowed us to determine maximum earthworm population densities considering soil mechanical properties and the energy stored in soil organic matter.

Analyses of GPR signals for characterization of ground conditions in urban areas

NASA Astrophysics Data System (ADS)

Hong, Won-Taek; Kang, Seonghun; Lee, Sung Jin; Lee, Jong-Sub

2018-05-01

Ground penetrating radar (GPR) is applied for the characterization of the ground conditions in urban areas. In addition, time domain reflectometry (TDR) and dynamic cone penetrometer (DCP) tests are conducted for the accurate analyses of the GPR images. The GPR images are acquired near a ground excavation site, where a ground subsidence occurred and was repaired. Moreover, the relative permittivity and dynamic cone penetration index (DCPI) are profiled through the TDR and DCP tests, respectively. As the ground in the urban area is kept under a low-moisture condition, the relative permittivity, which is inversely related to the electromagnetic impedance, is mainly affected by the dry density and is inversely proportional to the DCPI value. Because the first strong signal in the GPR image is shifted 180° from the emitted signal, the polarity of the electromagnetic wave reflected at the dense layer, where the reflection coefficient is negative, is identical to that of the first strong signal. The temporal-scaled GPR images can be accurately converted into the spatial-scaled GPR images using the relative permittivity determined by the TDR test. The distribution of the loose layer can be accurately estimated by using the spatial-scaled GPR images and reflection characteristics of the electromagnetic wave. Note that the loose layer distribution estimated in this study matches well with the DCPI profile and is visually verified from the endoscopic images. This study demonstrates that the GPR survey complemented by the TDR and DCP tests, may be an effective method for the characterization of ground conditions in an urban area.

In situ pore-pressure evolution during dynamic CPT measurements in soft sediments of the western Baltic Sea

NASA Astrophysics Data System (ADS)

Seifert, Annedore; Stegmann, Sylvia; Mörz, Tobias; Lange, Matthias; Wever, Thomas; Kopf, Achim

2008-08-01

We present in situ strength and pore-pressure measurements from 57 dynamic cone penetration tests in sediments of Mecklenburg ( n = 51), Eckernförde ( n = 2) and Gelting ( n = 4) bays, western Baltic Sea, characterised by thick mud layers and partially free microbial gas resulting from the degradation of organic material. In Mecklenburg and Eckernförde bays, sediment sampling by nine gravity cores served sedimentological characterisation, analyses of geotechnical properties, and laboratory shear tests. At selected localities, high-resolution echo-sounder profiles were acquired. Our aim was to deploy a dynamic cone penetrometer (CPT) to infer sediment shear strength and cohesion of the sea bottom as a function of fluid saturation. The results show very variable changes in pore pressure and sediment strength during the CPT deployments. The majority of the CPT measurements ( n = 54) show initially negative pore-pressure values during penetration, and a delayed response towards positive pressures thereafter. This so-called type B pore-pressure signal was recorded in all three bays, and is typically found in soft muds with high water contents and undrained shear strengths of 1.6-6.4 kPa. The type B signal is further affected by displacement of sediment and fluid upon penetration of the lance, skin effects during dynamic profiling, enhanced consolidation and strength of individual horizons, the presence of free gas, and a dilatory response of the sediment. In Mecklenburg Bay, the remaining small number of CPT measurements ( n = 3) show a well-defined peak in both pore pressure and cone resistance during penetration, i.e. an initial marked increase which is followed by exponential pore-pressure decay during dissipation. This so-called type A pore-pressure signal is associated with normally consolidated mud, with indurated clay layers showing significantly higher undrained shear strength (up to 19 kPa). In Eckernförde and Gelting bays pore-pressure response type B is exclusively found, while in Mecklenburg Bay types A and B were detected. Despite the striking similarities in incremental density increase and shear strength behaviour with depth, gas occurrence and subtle variations in the coarse-grained fraction cause distinct pore-pressure curves. Gaseous muds interbedded with silty and sandy layers are most common in the three bays, and the potential effect of free gas (i.e. undersaturated pore space) on in situ strength has to be explored further.

Overview of environmental investigations and remediations of leaks and spills in oil and gas fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobs, J.A.; Jacobs, O.T.; Traver, R.

Historic and current leaks and spills in oil and gas fields can involve a variety of hazardous compounds, can be located virtually anywhere on site, and may significantly degrade soils and groundwater quality. Environmental evaluation of historic and current leaks and spills in oil and gas fields occurs in the investigative stage, characterized by a site assessment and field evaluation. The site assessment includes a site survey, aerial photo interpretation, review of regulatory agency records, operators' records, previous work by consultants, and interviews with knowledgeable persons. The field evaluation, designed to examine the lateral and vertical extent of the spillmore » or leak, could include a soil gas survey, cone penetrometer, trenching, and drilling. Using these techniques, collected soil or groundwater samples can be analyzed in a laboratory to differentiate the various hazardous compounds on-site. Once an environmental investigation has been performed to define the vertical and lateral extent of a spill and the potential pathways that the hazardous compound will move to expose a given population, then remediation options can be designed. Remedial programs for hazardous compounds commonly found in oil and gas fields include the following in-situ technologies: volatilization, biodegradation, leaching and chemical reaction, vitrification, passive remediation, and isolation/containment. Non-in-situ technologies include land farming, incineration, asphalt incorporation, solidification/stabilization, groundwater extraction and treatment, chemical extraction, and excavation and offsite disposal. Factors affecting remedial measures are cost of technology, time available to finish remediation, technical feasibility, regulatory acceptance, and accessibility and availability of space in the remediation area.« less

Assessment of Different Sampling Methods for Measuring and Representing Macular Cone Density Using Flood-Illuminated Adaptive Optics.

PubMed

Feng, Shu; Gale, Michael J; Fay, Jonathan D; Faridi, Ambar; Titus, Hope E; Garg, Anupam K; Michaels, Keith V; Erker, Laura R; Peters, Dawn; Smith, Travis B; Pennesi, Mark E

2015-09-01

To describe a standardized flood-illuminated adaptive optics (AO) imaging protocol suitable for the clinical setting and to assess sampling methods for measuring cone density. Cone density was calculated following three measurement protocols: 50 × 50-μm sampling window values every 0.5° along the horizontal and vertical meridians (fixed-interval method), the mean density of expanding 0.5°-wide arcuate areas in the nasal, temporal, superior, and inferior quadrants (arcuate mean method), and the peak cone density of a 50 × 50-μm sampling window within expanding arcuate areas near the meridian (peak density method). Repeated imaging was performed in nine subjects to determine intersession repeatability of cone density. Cone density montages could be created for 67 of the 74 subjects. Image quality was determined to be adequate for automated cone counting for 35 (52%) of the 67 subjects. We found that cone density varied with different sampling methods and regions tested. In the nasal and temporal quadrants, peak density most closely resembled histological data, whereas the arcuate mean and fixed-interval methods tended to underestimate the density compared with histological data. However, in the inferior and superior quadrants, arcuate mean and fixed-interval methods most closely matched histological data, whereas the peak density method overestimated cone density compared with histological data. Intersession repeatability testing showed that repeatability was greatest when sampling by arcuate mean and lowest when sampling by fixed interval. We show that different methods of sampling can significantly affect cone density measurements. Therefore, care must be taken when interpreting cone density results, even in a normal population.

Assessment of Different Sampling Methods for Measuring and Representing Macular Cone Density Using Flood-Illuminated Adaptive Optics

PubMed Central

Feng, Shu; Gale, Michael J.; Fay, Jonathan D.; Faridi, Ambar; Titus, Hope E.; Garg, Anupam K.; Michaels, Keith V.; Erker, Laura R.; Peters, Dawn; Smith, Travis B.; Pennesi, Mark E.

2015-01-01

Purpose To describe a standardized flood-illuminated adaptive optics (AO) imaging protocol suitable for the clinical setting and to assess sampling methods for measuring cone density. Methods Cone density was calculated following three measurement protocols: 50 × 50-μm sampling window values every 0.5° along the horizontal and vertical meridians (fixed-interval method), the mean density of expanding 0.5°-wide arcuate areas in the nasal, temporal, superior, and inferior quadrants (arcuate mean method), and the peak cone density of a 50 × 50-μm sampling window within expanding arcuate areas near the meridian (peak density method). Repeated imaging was performed in nine subjects to determine intersession repeatability of cone density. Results Cone density montages could be created for 67 of the 74 subjects. Image quality was determined to be adequate for automated cone counting for 35 (52%) of the 67 subjects. We found that cone density varied with different sampling methods and regions tested. In the nasal and temporal quadrants, peak density most closely resembled histological data, whereas the arcuate mean and fixed-interval methods tended to underestimate the density compared with histological data. However, in the inferior and superior quadrants, arcuate mean and fixed-interval methods most closely matched histological data, whereas the peak density method overestimated cone density compared with histological data. Intersession repeatability testing showed that repeatability was greatest when sampling by arcuate mean and lowest when sampling by fixed interval. Conclusions We show that different methods of sampling can significantly affect cone density measurements. Therefore, care must be taken when interpreting cone density results, even in a normal population. PMID:26325414

Influence of sampling window size and orientation on parafoveal cone packing density

PubMed Central

Lombardo, Marco; Serrao, Sebastiano; Ducoli, Pietro; Lombardo, Giuseppe

2013-01-01

We assessed the agreement between sampling windows of different size and orientation on packing density estimates in images of the parafoveal cone mosaic acquired using a flood-illumination adaptive optics retinal camera. Horizontal and vertical oriented sampling windows of different size (320x160 µm, 160x80 µm and 80x40 µm) were selected in two retinal locations along the horizontal meridian in one eye of ten subjects. At each location, cone density tended to decline with decreasing sampling area. Although the differences in cone density estimates were not statistically significant, Bland-Altman plots showed that the agreement between cone density estimated within the different sampling window conditions was moderate. The percentage of the preferred packing arrangements of cones by Voronoi tiles was slightly affected by window size and orientation. The results illustrated the high importance of specifying the size and orientation of the sampling window used to derive cone metric estimates to facilitate comparison of different studies. PMID:24009995

Technical Factors Influencing Cone Packing Density Estimates in Adaptive Optics Flood Illuminated Retinal Images

PubMed Central

Lombardo, Marco; Serrao, Sebastiano; Lombardo, Giuseppe

2014-01-01

Purpose To investigate the influence of various technical factors on the variation of cone packing density estimates in adaptive optics flood illuminated retinal images. Methods Adaptive optics images of the photoreceptor mosaic were obtained in fifteen healthy subjects. The cone density and Voronoi diagrams were assessed in sampling windows of 320×320 µm, 160×160 µm and 64×64 µm at 1.5 degree temporal and superior eccentricity from the preferred locus of fixation (PRL). The technical factors that have been analyzed included the sampling window size, the corrected retinal magnification factor (RMFcorr), the conversion from radial to linear distance from the PRL, the displacement between the PRL and foveal center and the manual checking of cone identification algorithm. Bland-Altman analysis was used to assess the agreement between cone density estimated within the different sampling window conditions. Results The cone density declined with decreasing sampling area and data between areas of different size showed low agreement. A high agreement was found between sampling areas of the same size when comparing density calculated with or without using individual RMFcorr. The agreement between cone density measured at radial and linear distances from the PRL and between data referred to the PRL or the foveal center was moderate. The percentage of Voronoi tiles with hexagonal packing arrangement was comparable between sampling areas of different size. The boundary effect, presence of any retinal vessels, and the manual selection of cones missed by the automated identification algorithm were identified as the factors influencing variation of cone packing arrangements in Voronoi diagrams. Conclusions The sampling window size is the main technical factor that influences variation of cone density. Clear identification of each cone in the image and the use of a large buffer zone are necessary to minimize factors influencing variation of Voronoi diagrams of the cone mosaic. PMID:25203681

Technical factors influencing cone packing density estimates in adaptive optics flood illuminated retinal images.

PubMed

Lombardo, Marco; Serrao, Sebastiano; Lombardo, Giuseppe

2014-01-01

To investigate the influence of various technical factors on the variation of cone packing density estimates in adaptive optics flood illuminated retinal images. Adaptive optics images of the photoreceptor mosaic were obtained in fifteen healthy subjects. The cone density and Voronoi diagrams were assessed in sampling windows of 320×320 µm, 160×160 µm and 64×64 µm at 1.5 degree temporal and superior eccentricity from the preferred locus of fixation (PRL). The technical factors that have been analyzed included the sampling window size, the corrected retinal magnification factor (RMFcorr), the conversion from radial to linear distance from the PRL, the displacement between the PRL and foveal center and the manual checking of cone identification algorithm. Bland-Altman analysis was used to assess the agreement between cone density estimated within the different sampling window conditions. The cone density declined with decreasing sampling area and data between areas of different size showed low agreement. A high agreement was found between sampling areas of the same size when comparing density calculated with or without using individual RMFcorr. The agreement between cone density measured at radial and linear distances from the PRL and between data referred to the PRL or the foveal center was moderate. The percentage of Voronoi tiles with hexagonal packing arrangement was comparable between sampling areas of different size. The boundary effect, presence of any retinal vessels, and the manual selection of cones missed by the automated identification algorithm were identified as the factors influencing variation of cone packing arrangements in Voronoi diagrams. The sampling window size is the main technical factor that influences variation of cone density. Clear identification of each cone in the image and the use of a large buffer zone are necessary to minimize factors influencing variation of Voronoi diagrams of the cone mosaic.

Design of a Horizontal Penetrometer for Measuring On-the-Go Soil Resistance

PubMed Central

Topakci, Mehmet; Unal, Ilker; Canakci, Murad; Celik, Huseyin Kursat; Karayel, Davut

2010-01-01

Soil compaction is one of the main negative factors that limits plant growth and crop yield. Therefore, it is important to determine the soil resistance level and map it for the field to find solutions for the negative effects of the compaction. Nowadays, high powered communication technology and computers help us on this issue within the approach of precision agriculture applications. This study is focused on the design of a penetrometer, which can make instantaneous soil resistance measurements in the soil horizontally and data acquisition software based on the GPS (Global Positioning System). The penetrometer was designed using commercial 3D parametric solid modelling design software. The data acquisition software was developed in Microsoft Visual Basic.NET programming language. After the design of the system, manufacturing and assembly of the system was completed and then a field experiment was carried out. According to the data from GPS and penetration resistance values which are collected in Microsoft SQL Server database, a Kriging method by ArcGIS was used and soil resistance was mapped in the field for a soil depth of 40 cm. During operation, no faults, either in mechanical and software parts, were seen. As a result, soil resistance values of 0.2 MPa and 3 MPa were obtained as minimum and maximum values, respectively. In conclusion, the experimental results showed that the designed system works quite well in the field and the horizontal penetrometer is a practical tool for providing on-line soil resistance measurements. This study contributes to further research for the development of on-line soil resistance measurements and mapping within the precision agriculture applications. PMID:22163410

Design of a horizontal penetrometer for measuring on-the-go soil resistance.

PubMed

Topakci, Mehmet; Unal, Ilker; Canakci, Murad; Celik, Huseyin Kursat; Karayel, Davut

2010-01-01

Soil compaction is one of the main negative factors that limits plant growth and crop yield. Therefore, it is important to determine the soil resistance level and map it for the field to find solutions for the negative effects of the compaction. Nowadays, high powered communication technology and computers help us on this issue within the approach of precision agriculture applications. This study is focused on the design of a penetrometer, which can make instantaneous soil resistance measurements in the soil horizontally and data acquisition software based on the GPS (Global Positioning System). The penetrometer was designed using commercial 3D parametric solid modelling design software. The data acquisition software was developed in Microsoft Visual Basic.NET programming language. After the design of the system, manufacturing and assembly of the system was completed and then a field experiment was carried out. According to the data from GPS and penetration resistance values which are collected in Microsoft SQL Server database, a Kriging method by ArcGIS was used and soil resistance was mapped in the field for a soil depth of 40 cm. During operation, no faults, either in mechanical and software parts, were seen. As a result, soil resistance values of 0.2 MPa and 3 MPa were obtained as minimum and maximum values, respectively. In conclusion, the experimental results showed that the designed system works quite well in the field and the horizontal penetrometer is a practical tool for providing on-line soil resistance measurements. This study contributes to further research for the development of on-line soil resistance measurements and mapping within the precision agriculture applications.

Analysis of the 2H-evaporator scale samples (HTF-17-56, -57)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.; Coleman, C.; Diprete, D.

Savannah River National Laboratory analyzed scale samples from both the wall and cone sections of the 242-16H Evaporator prior to chemical cleaning. The samples were analyzed for uranium and plutonium isotopes required for a Nuclear Criticality Safety Assessment of the scale removal process. The analysis of the scale samples found the material to contain crystalline nitrated cancrinite and clarkeite. Samples from both the wall and cone contain depleted uranium. Uranium concentrations of 16.8 wt% 4.76 wt% were measured in the wall and cone samples, respectively. The ratio of plutonium isotopes in both samples is ~85% Pu-239 and ~15% Pu-238 bymore » mass and shows approximately the same 3.5 times higher concentration in the wall sample versus the cone sample as observed in the uranium concentrations. The mercury concentrations measured in the scale samples were higher than previously reported values. The wall sample contains 19.4 wt% mercury and the cone scale sample 11.4 wt% mercury. The results from the current scales samples show reasonable agreement with previous 242-16H Evaporator scale sample analysis; however, the uranium concentration in the current wall sample is substantially higher than previous measurements.« less

GY SAMPLING THEORY IN ENVIRONMENTAL STUDIES 1: ASSESSING SOIL SPLITTING PROTOCOLS

EPA Science Inventory

Five soil sample splitting methods (riffle splitting, paper cone riffle splitting, fractional shoveling, coning and quartering, and grab sampling) were evaluated with synthetic samples to verify Pierre Gy sampling theory expectations. Individually prepared samples consisting of l...

Integrating proximal soil sensing techniques and terrain indexes to generate 3D maps of soil restrictive layers in the Palouse region, Washington, USA

NASA Astrophysics Data System (ADS)

Poggio, Matteo; Brown, David J.; Gasch, Caley K.; Brooks, Erin S.; Yourek, Matt A.

2015-04-01

In the Palouse region of eastern Washington and northern Idaho (USA), spatially discontinuous restrictive layers impede rooting growth and water infiltration. Consequently, accurate maps showing the depth and spatial extent of these restrictive layers are essential for watershed hydrologic modeling appropriate for precision agriculture. In this presentation, we report on the use of a Visible and Near-Infrared (VisNIR) penetrometer fore optic to construct detailed maps of three wheat fields in the Palouse region. The VisNIR penetrometer was used to deliver in situ soil reflectance to an Analytical Spectral Devices (ASD, Boulder, CO, USA) spectrometer and simultaneously acquire insertion force. With a hydraulic push-type soil coring systems for insertion (e.g. Giddings), we collected soil spectra and insertion force data along 41m x 41m grid points (2 fields) and 50m x 50m grid points (1 field) to ≈80cm depth, in addition to interrogation points at 36 representative instrumented locations per field. At each of the 36 instrumented locations, two soil cores were extracted for laboratory determination of clay content and bulk density. We developed calibration models of soil clay content and bulk density with spectra and insertion force collected in situ, using partial least squares regression 2 (PLSR2). Applying spline functions, we delineated clay and bulk density profiles at each points (grid and 24 locations). The soil profiles were then used as inputs in a regression-kriging model with terrain indexes and ECa data (derived from an EM38 field survey, Geonics, Mississauga, Ontario, Canada) as covariates to generate 3D soil maps. Preliminary results show that the VisNIR penetrometer can capture the spatial patterns of restrictive layers. Work is ongoing to evaluate the prediction accuracy of penetrometer-derived 3D clay content and restriction layer maps.

Regional-scale integration of hydrological and geophysical data using Bayesian sequential simulation: application to field data

NASA Astrophysics Data System (ADS)

Ruggeri, Paolo; Irving, James; Gloaguen, Erwan; Holliger, Klaus

2013-04-01

Significant progress has been made with regard to the quantitative integration of geophysical and hydrological data at the local scale. However, extending corresponding approaches to the regional scale still represents a major challenge, yet is critically important for the development of groundwater flow and contaminant transport models. To address this issue, we have developed a regional-scale hydrogeophysical data integration technique based on a two-step Bayesian sequential simulation procedure. The objective is to simulate the regional-scale distribution of a hydraulic parameter based on spatially exhaustive, but poorly resolved, measurements of a pertinent geophysical parameter and locally highly resolved, but spatially sparse, measurements of the considered geophysical and hydraulic parameters. To this end, our approach first involves linking the low- and high-resolution geophysical data via a downscaling procedure before relating the downscaled regional-scale geophysical data to the high-resolution hydraulic parameter field. We present the application of this methodology to a pertinent field scenario, where we consider collocated high-resolution measurements of the electrical conductivity, measured using a cone penetrometer testing (CPT) system, and the hydraulic conductivity, estimated from EM flowmeter and slug test measurements, in combination with low-resolution exhaustive electrical conductivity estimates obtained from dipole-dipole ERT meausurements.

Effect of crumb rubber on the mechanical properties of crushed recycled pavement materials.

PubMed

Li, Jie; Saberian, Mohammad; Nguyen, Bao Thach

2018-07-15

The low-carbon footprint of using recycled construction and demolition (C&D) aggregates in civil engineering infrastructure applications has been considered to be a significant solution for the replacement of conventional pavement aggregates. Investigations regarding the use of crumb rubber in the base and subbase layers of pavement have been well documented. However, information on the effects of crumb rubber and its size within C&D aggregates as the base/subbase layers is still very limited. In this study, crumb rubber with particle sizes ranging from 400 to 600 μm (fine) to 10-15 mm (coarse), 20 mm recycled crushed concrete (RCC), and 20 mm crushed rock (CR) were used. The crumb rubber was added to the two groups of C&D aggregates at 0.5, 1 and 2% by weight percentages of the aggregates. The effect of crumb rubber on the mechanical properties (such as California bearing ratio, unconfined compressive strength, aggregate crushing value, dynamic lightweight cone penetrometer, Clegg impact value, Los Angeles abrasion values, and resilient modulus) of the C&D aggregates was then examined. Based on the experimental test results, it was found that crumb rubber can be recycled as a waste material for the base and subbase layers in the pavement. Copyright © 2018 Elsevier Ltd. All rights reserved.

A review of an attempt to create shatter cones with magnetic flyer plate technology

NASA Technical Reports Server (NTRS)

Linnerud, H. J.

1981-01-01

The feasibility of creating shatter cones in a controlled laboratory environment is discussed. Magnetic flyer plate technology, which generates high amplitude shock waves in test materials is discribed. Considerable sample shear and break up was observed, however, no shatter cones are found in the tested samples.

Forcasting Shortleaf Pine Seed Crops in the Ouachita Mountains

Treesearch

Michael G. Shelton; Robert F. Wittwer

2004-01-01

We field tested a cone-rating system to forecast seed crops from 1993 to 1996 in 28 shortleaf pine (Pinus echinata Mill.) stands, which represented a wide range of stand conditions. Sample trees were visually assigned to one of three cone-density classes based on cone spacing, occurrence of cones in clusters, and distribution of cones within the...

Radiocarbon Dates from Volcanic Deposits of the Chaos Crags and Cinder Cone Eruptive Sequences and Other Deposits, Lassen Volcanic National Park and Vicinity, California

USGS Publications Warehouse

Clynne, Michael A.; Christiansen, Robert L.; Trimble, Deborah A.; McGeehin, John P.

2008-01-01

This contribution reports radiocarbon ages obtained from charcoal, wood and other samples collected between 1979 and 2001 in Lassen Volcanic National Park and vicinity and a few samples from other nearby localities. Most of the samples are from the Chaos Crags and Cinder Cone eruptive sequences. Brief summaries are given of the Chaos Crags and Cinder Cone eruptive sequences.

Variability in human cone topography assessed by adaptive optics scanning laser ophthalmoscopy

PubMed Central

Zhang, Tianjiao; Godara, Pooja; Blanco, Ernesto R.; Griffin, Russell L; Wang, Xiaolin; Curcio, Christine A.; Zhang, Yuhua

2015-01-01

Purpose To assess between- and within-individual variability of macular cone topography in the eyes of young adults. Design Observational case series. Methods Cone photoreceptors in 40 eyes of 20 subjects aged 19–29 years with normal maculae were imaged using a research adaptive optics scanning laser ophthalmoscope. Refractive errors ranged from −3.0 D to 0.63 D and differed by <0.50 D in fellow eyes. Cone density was assessed on a two-dimensional sampling grid over the central 2.4 mm × 2.4 mm. Between-individual variability was evaluated by coefficient of variation (CV). Within-individual variability was quantified by maximum difference and root-mean-square (RMS). Cones were cumulated over increasing eccentricity. Results Peak densities of foveal cones are 168,162 ± 23,529 cones/mm2 (mean ± SD) (CV = 0.14). The number of cones within the cone-dominated foveola (0.8–0.9 mm diameter) is 38,311 ± 2,319 (CV = 0.06). The RMS cone density difference between fellow eyes is 6.78%, and the maximum difference is 23.6%. Mixed model statistical analysis found no difference in the association between eccentricity and cone density in the superior/nasal (p=0.8503), superior/temporal (p=0.1551), inferior/nasal (p=0.8609), and inferior/temporal (p=0.6662) quadrants of fellow eyes. Conclusions New instrumentation imaged the smallest foveal cones, thus allowing accurate assignment of foveal centers and assessment of variability in macular cone density in a large sample of eyes. Though cone densities vary significantly in the fovea, the total number of foveolar cones are very similar both between- and within-subjects. Thus, the total number of foveolar cones may be an important measure of cone degeneration and loss. PMID:25935100

A marine dynamic penetrometer for the determination of sea floor geotechnical properties

NASA Astrophysics Data System (ADS)

Stephan, S.; Kaul, N. E.; Villinger, H. W.

2013-12-01

We present a seafloor lance penetration monitoring system: the Lance Insertion Retardation Meter (LIRmeter). The device can be used to infer geotechnical seafloor properties, such as bearing capacity by monitoring the deceleration of a free-fall penetrating lance. The deceleration record can be furthermore used to estimate mean grain size and mud content of the sea floor as well as total penetration depth. The LIRmeter is contained in a pressure vessel (440 x 110 mm) and equipped with accelerometers of different sensitivities to (i) determine sea floor resistance during penetration and (ii) to generate a depth axis. Typically, measurements are carried out in a pogo style fashion to allow a rapid measurement progress during field campaigns. The LIRmeter is intended to determine sea floor properties on the sole basis of deceleration measurements in order to achieve a mechanically and electronically robust system. Data is sampled at a resolution of 16 bit and at a rate of typically 500 Hz for each channel. The device can either be installed in any type of lance i.e. marine heat flow probes, gravity corers, piston corers or can be used in combination with a purpose built lance as a standalone instrument. It has a usable length of four meters, a total weight of 280 kg in air and can be operated up to full ocean depth (6000m). The bearing capacity of the sea floor is a critical factor for marine engineering projects such as burial of marine cables, pipeline laying and foundations. Knowledge of the mud content can provide constraints for the estimation of hydraulic conductivity. The identification of weak zones along a slope can moreover provide vital information for risk assessment studies. Traditionally, frame based, quasi static Cone Penetration Tests (CPT) or sampling methods like gravity coring are used to conduct these types of investigation. In comparison to established but time consuming and rather costly methods, the LIRmeter is intended (i) for near surface investigations and/or (ii) to complement and connect conventional but isolated CPT measurements in a very efficient and rapid way. We show results from measurements in the North Sea, as well as results of laboratory experiments. During sea trials, the LIRmeter was equipped with an additional CPT sensor, which delivered data for cone (tip) resistance, sleeve friction and pore pressure, thus allowing a direct comparison between results of the acceleration measurements and results from conventional CPT sensors. The laboratory measurements were also carried out using both acceleration and tip resistance sensors. Resulting values show a very good agreement between tip resistance calculated from deceleration data and tip resistance from direct laboratory and field measurements. The influence of sediment type (mainly mud content) will be discussed within the context of laboratory measurements.

In-situ geotechnical investigation of sediment dynamics over `The Bar', Raglan, New Zealand

NASA Astrophysics Data System (ADS)

Stark, N.; Greer, D.; Phillips, D. J.; Borrero, J. C.; Harrison, S.; Kopf, A.

2010-12-01

The geotechnical characteristics of surficial sediments on a highly mobile, N-S-oriented ebb tidal shoal (‘The Bar’) near the entrance to Whaingaroa Harbour, in Raglan, NZ, were investigated using the dynamic penetrometer Nimrod, which is suitable for deployments in areas characterized by strong currents and active wave climate common to this site. Vertical sediment strength, based upon penetrometer deceleration and a quasi-static bearing capacity equivalent, was profiled at 23 positions along as well as in the vicinity of ‘The Bar’ during slack water. Recently deposited or loose sediment was detected as a top layer of lower sediment strength (quasi-static bearing capacity equivalent [qs. bc.] < 10 kPa) over a stiff substratum (mean maximum qs. bs. ~ 105 kPa), and quantified (thickness: 0 - 7 cm) indicating areas of sediment accumulation and areas of sediment erosion. These results were correlated to mean current velocities and directions predicted by ASR Ltd.’s Whaingaroa Harbour Model. In relation to sediment dynamics, ‘The Bar’ area can be divided into different zones: (i) the channel connecting ‘The Bar’ to the harbor, (ii) the southern arm, (iii) the mid-section, (iv) the northern arm, and (v, vi) the northern and southern wings covering the area between ‘The Bar’ and the shore. The channel is characterized by high current velocities (up to 1.7 m/s) along the W-E-axis, suggesting strong sediment erosion and no (re-)deposition. However, despite the high mean current velocities, the penetrometer results hint at sediment deposition. This is most likely explained by the deep trench in the channel that could trap sediment. Comparing the northern and the southern wing, the currents follow the bathymetry and coastline alignment and are mirrored at the W-E-axis, but the mean current velocities are higher at the southern wing (northern wing: up to 0.4 m/s; southern wing: up to 0.6 m/s). The penetrometer results suggest strong sediment erosion on the southern wing (qs. bc. up to 155 kPa, top layer thickness ~ 2 cm), and show no evidence of sediment remobilization on the northern wing (no layering). On the northern and southern arms, low currents (~ 0.3 m/s) with very mixed directions were predicted. In front (west) of the most southern corner an area of strong sediment accumulation was localized following the penetrometer results (top layer thickness: 7 cm). This leads to the hypothesis that in the ebb-shoal system at Whaingaroa Harbour, mobile sediment is mainly transported via the southern wing of the ‘The Bar’ potentially leading to an increase of sediment erosion in this area due to effects like sanding. Sediment deposition might occur in the trench of the channel as well as in the vicinity of the southernmost portion of the sandbar. This matches observations according to which the southern arm shifted about 220 m whereas the northern arm only moved 20 m within one year. The in-situ penetrometer as well as the numerical results compare favorably with observations of ‘The Bar’s morphology. Both methods provide valuable insights which enhance our understanding of the sediment dynamics in this area.

Number and Distribution of Mouse Retinal Cone Photoreceptors: Differences between an Albino (Swiss) and a Pigmented (C57/BL6) Strain

PubMed Central

Jiménez-López, Manuel; Alburquerque-Béjar, Juan J.; Nieto-López, Leticia; García-Ayuso, Diego; Villegas-Pérez, Maria P.; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta

2014-01-01

We purpose here to analyze and compare the population and topography of cone photoreceptors in two mouse strains using automated routines, and to design a method of retinal sampling for their accurate manual quantification. In whole-mounted retinas from pigmented C57/BL6 and albino Swiss mice, the longwave-sensitive (L) and the shortwave-sensitive (S) opsins were immunodetected to analyze the population of each cone type. In another group of retinas both opsins were detected with the same fluorophore to quantify all cones. In a third set of retinas, L-opsin and Brn3a were immunodetected to determine whether L-opsin+cones and retinal ganglion cells (RGCs) have a parallel distribution. Cones and RGCs were automatically quantified and their topography illustrated with isodensity maps. Our results show that pigmented mice have a significantly higher number of total cones (all-cones) and of L-opsin+cones than albinos which, in turn, have a higher population of S-opsin+cones. In pigmented animals 40% of cones are dual (cones that express both opsins), 34% genuine-L (cones that only express the L-opsin), and 26% genuine-S (cones that only express the S-opsin). In albinos, 23% of cones are genuine-S and the proportion of dual cones increases to 76% at the expense of genuine-L cones. In both strains, L-opsin+cones are denser in the central than peripheral retina, and all-cones density increases dorso-ventrally. In pigmented animals S-opsin+cones are scarce in the dorsal retina and very numerous in the ventral retina, being densest in its nasal aspect. In albinos, S-opsin+cones are abundant in the dorsal retina, although their highest densities are also ventral. Based on the densities of each cone population, we propose a sampling method to manually quantify and infer their total population. In conclusion, these data provide the basis to study cone degeneration and its prevention in pathologic conditions. PMID:25029531

Ablation and cone formation mechanism on CR-39 by ArF laser irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shakeri Jooybari, B., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir; Nuclear Science and Technology Research Institute NSRT, Tehran; Afarideh, H., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir

In this work, chemical properties, surface modification, and micro structures formation on ablated polyallyl di-glycol carbonate (CR-39) polymer by ArF laser irradiation (λ = 193 nm) at various fluences and pulse number were investigated. CR-39 samples have been irradiated with an ArF laser (193 nm) at a repetition rate of 1 Hz. Threshold fluence of ablation and effective absorption coefficient of CR-39 were determined. Conical microstructures (Taylor cone) formed on laser-ablated CR-39 exhibit: smooth, Taylor cone shape walls and sharp tips together with interference and well defined fringe-structure with a period of 230 nm, around cone base. Mechanism of cone formation and cone evolution of CR-39more » ablated surface were investigated by change of fluences (at a given pulse number) and pulse number (at a given fluence). Cone height, cone base, and region of interface were increased in micrometer steps by increasing the total fluence. Depression on the base of the cone and the circular fringe were simulated. FTIR spectra were measured and energy dispersive x-ray analysis of irradiated and un-irradiated samples was performed.« less

Persisting effects of armored military maneuvers on some soils of the Mojave Desert

USGS Publications Warehouse

Prose, D.V.

1985-01-01

Soil compaction and substrate modification produced during large-scale armored military maneuvers in the early 1940s were examined in 1981 at seven sites in California's eastern Mojave Desert Recording penetrometer measurements show that tracks left by a single pass of an M3 "medium" tank have average soil resistance values that are 50% greater than those of the surrounding untracked soil in the upper 20 cm At one site, measurements made along short segments of track that have been visually eliminated by erosion and deposition processes show a 73% increase in penetrometer resistance over adjacent, undisturbed soils Dirt roadways at three former base camp locations could not be penetrated below 5-10 cm because of extreme compaction Soil bulk density was not as sensitive an indicator of soil compaction as was penetrometer resistance Density values in the upper 10 cm of soil are not significantly different between tank tracks and undisturbed soils at most sites, and roadways at two base camps show an average increase in bulk density of only 12% over adjacent soils. Trench excavations across tank tracks show that physical modifications of the substrate can extend vertically beneath a track to a depth of 25 cm and outward from a track's edge to 50 cm These soil disturbances are probably major factors that encourage accelerated soil erosion throughout the manuever area and also retard or prevent the return of vegetation to pre-disturbance conditions ?? 1985 Springer-Verlag New York Inc.

A comparison of four geophysical methods for determining the shear wave velocity of soils

USGS Publications Warehouse

Anderson, N.; Thitimakorn, T.; Ismail, A.; Hoffman, D.

2007-01-01

The Missouri Department of Transportation (MoDOT) routinely acquires seismic cone penetrometer (SCPT) shear wave velocity control as part of the routine investigation of soils within the Mississippi Embayment. In an effort to ensure their geotechnical investigations are as effective and efficient as possible, the SCPT tool and several available alternatives (crosshole [CH]; multichannel analysis of surface waves [MASW]; and refraction microtremor [ReMi]) were evaluated and compared on the basis of field data acquired at two test sites in southeast Missouri. These four methods were ranked in terms of accuracy, functionality, cost, other considerations, and overall utility. It is concluded that MASW data are generally more reliable than SCPT data, comparable to quality ReMi data, and only slightly less accurate than CH data. However, the other advantages of MASW generally make it a superior choice over the CH, SCPT, and ReMi methods for general soil classification purposes to depths of 30 m. MASW data are less expensive than CH data and SCPT data and can normally be acquired in areas inaccessible to drill and SCPT rigs. In contrast to the MASW tool, quality ReMi data can be acquired only in areas where there are interpretable levels of "passive" acoustic energy and only when the geophone array is aligned with the source(s) of such energy.

Surface and downhole shear wave seismic methods for thick soil site investigations

USGS Publications Warehouse

Hunter, J.A.; Benjumea, B.; Harris, J.B.; Miller, R.D.; Pullan, S.E.; Burns, R.A.; Good, R.L.

2002-01-01

Shear wave velocity-depth information is required for predicting the ground motion response to earthquakes in areas where significant soil cover exists over firm bedrock. Rather than estimating this critical parameter, it can be reliably measured using a suite of surface (non-invasive) and downhole (invasive) seismic methods. Shear wave velocities from surface measurements can be obtained using SH refraction techniques. Array lengths as large as 1000 m and depth of penetration to 250 m have been achieved in some areas. High resolution shear wave reflection techniques utilizing the common midpoint method can delineate the overburden-bedrock surface as well as reflecting boundaries within the overburden. Reflection data can also be used to obtain direct estimates of fundamental site periods from shear wave reflections without the requirement of measuring average shear wave velocity and total thickness of unconsolidated overburden above the bedrock surface. Accurate measurements of vertical shear wave velocities can be obtained using a seismic cone penetrometer in soft sediments, or with a well-locked geophone array in a borehole. Examples from thick soil sites in Canada demonstrate the type of shear wave velocity information that can be obtained with these geophysical techniques, and show how these data can be used to provide a first look at predicted ground motion response for thick soil sites. ?? 2002 Published by Elsevier Science Ltd.

Spatial variability of detrended soil plow layer penetrometer resistance transect in a sugarcane field

NASA Astrophysics Data System (ADS)

Pérez, Luis D.; Cumbrera, Ramiro; Mato, Juan; Millán, Humberto; Tarquis, Ana M.

2015-04-01

Spatial variability of soil properties is relevant for identifying those zones with physical degradation. In this sense, one has to face the problem of identifying the origin and distribution of spatial variability patterns (Brouder et al., 2001; Millán et al., 2012). The objective of the present work was to quantify the spatial structure of soil penetrometer resistance (PR) collected from a transect data consisted of 221 points equidistant. In each sampling, readings were obtained from 0 cm till 70 cm of depth, with an interval of 5 cm (Pérez, 2012). The study was conducted on a Vertisol (Typic Hapludert) dedicated to sugarcane (Saccharum officinarum L.) production during the last sixty years (Pérez et al., 2010). Recently, scaling approach has been applied on the determination of the scaling data properties (Tarquis et al., 2008; Millán et al., 2012; Pérez, 2012). We focus in the Hurst analysis to characterize the data variability for each depth. Previously a detrended analysis was conducted in order to better study de intrinsic variability of the series. The Hurst exponent (H) for each depth was estimated showing a characteristic pattern and differentiating PR evolution in depth. References Brouder, S., Hofmann, B., Reetz, H.F., 2001. Evaluating spatial variability of soil parameters for input management. Better Crops 85, 8-11. Millán, H; AM Tarquís, Luís D. Pérez, Juan Mato, Mario González-Posada, 2012. Spatial variability patterns of some Vertisol properties at a field scale using standardized data. Soil and Tillage Research, 120, 76-84. Pérez, Luís D. 2012. Influencia de la maquinaria agrícola sobre la variabilidad espacial de la compactación del suelo. Aplicación de la metodología geoestadística-fractal. PhD thesis, UPM (In Spanish). Pérez, Luís D., Humberto Millán, Mario González-Posada 2010. Spatial complexity of soil plow layer penetrometer resistance as influenced by sugarcane harvesting: A prefractal approach. Soil and Tillage Research, 110(1), 77-86. Tarquis, A.M., N. Bird, M.C. Cartagena, A. Whitmore and Y. Pachepsky, 2008. Multiscale entropy-based analyses of soil transect data. Vadose Zone Journal, 7(2), 563-569.

Strength Measurements of Archive K Basin Sludge Using a Soil Penetrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delegard, Calvin H.; Schmidt, Andrew J.; Chenault, Jeffrey W.

2011-12-06

Spent fuel radioactive sludge present in the K East and K West spent nuclear fuel storage basins now resides in the KW Basin in six large underwater engineered containers. The sludge will be dispositioned in two phases under the Sludge Treatment Project: (1) hydraulic retrieval into sludge transport and storage containers (STSCs) and transport to interim storage in Central Plateau and (2) retrieval from the STSCs, treatment, and packaging for shipment to the Waste Isolation Pilot Plant. In the years the STSCs are stored, sludge strength is expected to increase through chemical reaction, intergrowth of sludge crystals, and compaction andmore » dewatering by settling. Increased sludge strength can impact the type and operation of the retrieval equipment needed prior to final sludge treatment and packaging. It is important to determine whether water jetting, planned for sludge retrieval from STSCs, will be effective. Shear strength is a property known to correlate with the effectiveness of water jetting. Accordingly, the unconfined compressive strengths (UCS) of archive K Basin sludge samples and sludge blends were measured using a pocket penetrometer modified for hot cell use. Based on known correlations, UCS values can be converted to shear strengths. Twenty-six sludge samples, stored in hot cells for a number of years since last being disturbed, were identified as potential candidates for UCS measurement and valid UCS measurements were made for twelve, each of which was found as moist or water-immersed solids at least 1/2-inch deep. Ten of the twelve samples were relatively weak, having consistencies described as 'very soft' to 'soft'. Two of the twelve samples, KE Pit and KC-4 P250, were strong with 'very stiff' and 'stiff' consistencies described, respectively, as 'can be indented by a thumb nail' or 'can be indented by thumb'. Both of these sludge samples are composites collected from KE Basin floor and Weasel Pit locations. Despite both strong sludges having relatively high iron concentrations, attribution of their high strengths to this factor could not be made with confidence as other measured sludge samples, also from the KE Basin floor and of high iron concentration, were relatively weak. The observed UCS and shear strengths for the two strong sludges were greater than observed in any prior testing of K Basin sludge except for sludge processed at 185 C under hydrothermal conditions.« less

Quantification of Juniperus Ashei Pollen Production for the Development of Forecasting Models

NASA Technical Reports Server (NTRS)

Bunderson, L. D.; Levetin, E.

2010-01-01

Juniperus ashei pollen is considered one of the most allergenic species of Cupressaceae in North America. Juniperus ashei is distributed throughout central Texas, Northern Mexico, the Arbuckle Mountains of south central Oklahoma, and the Ozark Mountains of northern Arkansas and southwestern Missouri. The large amount of airborne pollen that J. ashei produces affects inhabitants of cities and towns adjacent to juniper woodland areas and because juniper pollen can be transported over long distances, it affects populations that are far away. In order to create a dynamic forecast system for allergy and asthma sufferers, pollen production must be estimated. Estimation of pollen production requires the estimation of male cone production. Two locations in the Arbuckle Mountains of Oklahoma and 4 locations in the Edwards Plateau region of Texas were chosen as sampling sites. Trees were measured to determine approximate size. Male to female ratio was determined and pollen cone production was estimated using a qualitative scale from 0 to 2. Cones were counted from harvested 1/8 sections of representative trees. The representative trees were measured and approximate surface area of the tree was calculated. Using the representative tree data, the number of cones per square meter was calculated for medium production (1) and high production (2) trees. These numbers were extrapolated to calculate cone production in other trees sampled. Calibration was achieved within each location's sub-plot by counting cones on 5 branches collected from 5 sides of both high production and medium production trees. The total area sampled in each location was 0.06 hectare and total cone production varied greatly from location to location. The highest production area produced 5.8 million cones while the lowest production area produced 72,000 cones. A single representative high production tree in the Arbuckle Mountains produced 1.38 million cones. The number of trees per location was relatively uniform, but the number of high cone production trees varied greatly. Although there is great diversity in the locations making it difficult to determine which factors are most important, cone production was well correlated with certain stand characteristics including trunk diameter.

Early Cone Setting in Picea abies acrocona Is Associated with Increased Transcriptional Activity of a MADS Box Transcription Factor1[W][OA

PubMed Central

Uddenberg, Daniel; Reimegård, Johan; Clapham, David; Almqvist, Curt; von Arnold, Sara; Emanuelsson, Olof; Sundström, Jens F.

2013-01-01

Conifers normally go through a long juvenile period, for Norway spruce (Picea abies) around 20 to 25 years, before developing male and female cones. We have grown plants from inbred crosses of a naturally occurring spruce mutant (acrocona). One-fourth of the segregating acrocona plants initiate cones already in their second growth cycle, suggesting control by a single locus. The early cone-setting properties of the acrocona mutant were utilized to identify candidate genes involved in vegetative-to-reproductive phase change in Norway spruce. Poly(A+) RNA samples from apical and basal shoots of cone-setting and non-cone-setting plants were subjected to high-throughput sequencing (RNA-seq). We assembled and investigated 33,383 expressed putative protein-coding acrocona transcripts. Eight transcripts were differentially expressed between selected sample pairs. One of these (Acr42124_1) was significantly up-regulated in apical shoot samples from cone-setting acrocona plants, and the encoded protein belongs to the MADS box gene family of transcription factors. Using quantitative real-time polymerase chain reaction with independently derived plant material, we confirmed that the MADS box gene is up-regulated in both needles and buds of cone-inducing shoots when reproductive identity is determined. Our results constitute important steps for the development of a rapid cycling model system that can be used to study gene function in conifers. In addition, our data suggest the involvement of a MADS box transcription factor in the vegetative-to-reproductive phase change in Norway spruce. PMID:23221834

A method for cone fitting based on certain sampling strategy in CMM metrology

NASA Astrophysics Data System (ADS)

Zhang, Li; Guo, Chaopeng

2018-04-01

A method of cone fitting in engineering is explored and implemented to overcome shortcomings of current fitting method. In the current method, the calculations of the initial geometric parameters are imprecise which cause poor accuracy in surface fitting. A geometric distance function of cone is constructed firstly, then certain sampling strategy is defined to calculate the initial geometric parameters, afterwards nonlinear least-squares method is used to fit the surface. The experiment is designed to verify accuracy of the method. The experiment data prove that the proposed method can get initial geometric parameters simply and efficiently, also fit the surface precisely, and provide a new accurate way to cone fitting in the coordinate measurement.

Soil strength and macropore volume limit root elongation rates in many UK agricultural soils.

PubMed

Valentine, Tracy A; Hallett, Paul D; Binnie, Kirsty; Young, Mark W; Squire, Geoffrey R; Hawes, Cathy; Bengough, A Glyn

2012-07-01

Simple indicators of crop and cultivar performance across a range of soil types and management are needed for designing and testing sustainable cropping practices. This paper determined the extent to which soil chemical and physical properties, particularly soil strength and pore-size distribution influences root elongation in a wide range of agricultural top soils, using a seedling-based indicator. Intact soil cores were sampled from the topsoil of 59 agricultural fields in Scotland, representing a wide geographic spread, range of textures and management practices. Water release characteristics, dry bulk density and needle penetrometer resistance were measured on three cores from each field. Soil samples from the same locations were sieved, analysed for chemical characteristics, and packed to dry bulk density of 1.0 g cm(-3) to minimize physical constraints. Root elongation rates were determined for barley seedlings planted in both intact field and packed soil cores at a water content close to field capacity (-20 kPa matric potential). Root elongation in field soil was typically less than half of that in packed soils. Penetrometer resistance was typically between 1 and 3 MPa for field soils, indicating the soils were relatively hard, despite their moderately wet condition (compared with <0.2 MPa for packed soil). Root elongation was strongly linked to differences in physical rather than chemical properties. In field soil root elongation was related most closely to the volume of soil pores between 60 µm and 300 µm equivalent diameter, as estimated from water-release characteristics, accounting for 65.7 % of the variation in the elongation rates. Root elongation rate in the majority of field soils was slower than half of the unimpeded (packed) rate. Such major reductions in root elongation rates will decrease rooting volumes and limit crop growth in soils where nutrients and water are scarce.

Pyrolysis kinetics and combustion of thin wood using advanced cone calorimetry test method

Treesearch

Mark A. Dietenberger

2011-01-01

Mechanistic pyrolysis kinetics analysis of extractives, holocellulose, and lignin in solid wood over entire heating regime was possible using specialized cone calorimeter test and new mathematical analysis tools. Added hardware components include: modified sample holder for thin specimen with tiny thermocouples, methane ring burner with stainless steel mesh above cone...

Resource use and clonal differences in attack rate by the Douglas-fir seed chalcid, Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), in France

Treesearch

Nancy Rappaport; Alain Roques

1991-01-01

The within-cone distribution of Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), the Douglas-fir seed chalcid, infesting Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] cones from north-central France was compared with that in samples from California. Results indicate that the mid-region of cones was more intensively...

Volatile organic compound sensing devices

DOEpatents

Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

1995-08-29

Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

Volatile organic compound sensing devices

DOEpatents

Lancaster, Gregory D.; Moore, Glenn A.; Stone, Mark L.; Reagen, William K.

1995-01-01

Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

Submarine Rejuvenated-Stage Lavas Offshore Molokai, Oahu, Kauai, and Niihau, Hawaii

NASA Astrophysics Data System (ADS)

Clague, D. A.; Cousens, B. L.; Davis, A. S.; Dixon, J. E.; Hon, K.; Moore, J. G.; Reynolds, J. R.

2003-12-01

Rejuvenated-stage lavas from the Hawaiian Islands form many distinctive landmarks, such as Diamond Head. They have been relatively well studied due to their primitive, strongly alkaline compositions (alkalic basalt, basanite, nephelinite, melilitite, phonolite). More recently, compositionally similar lavas have been mapped and sampled on the deep seafloor around the islands. Rejuvenated-stage cones also occur on the submarine flanks of the islands. A Pisces V submersible dive collected samples from the only submarine cone on the north slope of East Molokai. The alkalic basalt to basanite composition lava is similar to the subaerial Kalaupapa basalt (Clague and Moore, 2003). MBARI Tiburon ROV dives recovered nephelinite from a lone steep cone on the northeast slope of Oahu, alkalic basalt from two shallow steep cones just west of the Koko Rift, and alkalic basalt from the submarine flank of Diamond Head on Oahu's south flank. These lavas are generally similar to subaerial Honolulu Volcanics, although the isotopic data extend to higher Sr isotopic values. Other MBARI Tiburon ROV dives recovered alkalic basalt and basanite from 8 separate steep cones on the south flank of Kauai. Once again, these lavas are chemically similar to those from the subaerial Koloa Volcanics. Samples from one of these cones contained common xenoliths of upper mantle lherzolite and harzburgite. Seven MBARI Tiburon ROV dives on the northwest flank of Niihau sampled 6 flat-topped cones and 5 pointed cones. The lavas from the flat-topped cones are alkalic basalt similar to rejuvenated Kiekie Basalt on Niihau Island whereas the lavas from the pointed cones are basanite, hawaiite, and tephrophonolite that are chemically distinct from the Kiekie Basalt, but similar to rejuvenated-stage lavas on Kauai and Oahu. Volcaniclastic deposits were observed and sampled at many of the sites offshore Niihau, Kauai, and Oahu, as well as the North Arch. Breadcrust and spindle bombs and spatter were found offshore Kauai as deep as 1500 m, in addition to finer volcaniclastic deposits consisting of vesicular angular glass fragments, which also occur offshore Oahu and in the North Arch as deep as 4100 m (Davis and Clague, submitted). The glass data from all these deposits as well as on pillow and sheet flow rinds from Oahu, Molokai, Niihau, Kauai, North Arch, South Arch, Southwest Oahu volcanic field, and some of the cones between Oahu and Kauai demonstrate that rejuvenated stage lavas did not erupt as near-primary melts, but rather as crystal-rich magmas whose bulk compositions approach primary magma compositions. The low-MgO contents of almost all the glasses indicate that these magmas cooled and crystallized significantly during transit through the cool lithosphere. The distribution of these lavas on the islands, on the flanks of some islands, and on the deep seafloor suggest that the melting region around the Hawaiian hot-spot is at least 400 km across.

Image reconstruction in cone-beam CT with a spherical detector using the BPF algorithm

NASA Astrophysics Data System (ADS)

Zuo, Nianming; Zou, Yu; Jiang, Tianzi; Pan, Xiaochuan

2006-03-01

Both flat-panel detectors and cylindrical detectors have been used in CT systems for data acquisition. The cylindrical detector generally offers a sampling of a transverse image plane more uniformly than does a flat-panel detector. However, in the longitudinal dimension, the cylindrical and flat-panel detectors offer similar sampling of the image space. In this work, we investigate a detector of spherical shape, which can yield uniform sampling of the 3D image space because the solid angle subtended by each individual detector bin remains unchanged. We have extended the backprojection-filtration (BPF) algorithm, which we have developed previously for cone-beam CT, to reconstruct images in cone-beam CT with a spherical detector. We also conduct computer-simulation studies to validate the extended BPF algorithm. Quantitative results in these numerical studies indicate that accurate images can be obtained from data acquired with a spherical detector by use of our extended BPF cone-beam algorithms.

Vacuum probe surface sampler

NASA Technical Reports Server (NTRS)

Zahlava, B. A. (Inventor)

1973-01-01

A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacuum source is frictionally attached to a cone assembly terminating in a flared tip adapted to be passed over the surface to be sampled. A fine mesh screen carried by the vacuum head provides support for a membrane filter which collects the microorganisms or other particles. The head assembly is easily removed from the cone assembly without contacting the cone assembly with human hands.

The organization of the cone photoreceptor mosaic measured in the living human retina

PubMed Central

Sawides, Lucie; de Castro, Alberto; Burns, Stephen A.

2016-01-01

The cone photoreceptors represent the initial fundamental sampling step in the acquisition of visual information. While recent advances in adaptive optics have provided increasingly precise estimates of the packing density and spacing of the cone photoreceptors in the living human retina, little is known about the local cone arrangement beyond a tendency towards hexagonal packing. We analyzed the cone mosaic in data from 10 normal subjects. A technique was applied to calculate the local average cone mosaic structure which allowed us to determine the hexagonality, spacing and orientation of local regions. Using cone spacing estimates, we find the expected decrease in cone density with retinal eccentricity and higher densities along the horizontal meridians as opposed to the vertical meridians. Orientation analysis reveals an asymmetry in the local cone spacing of the hexagonal packing, with cones having a larger local spacing along the horizontal direction. This horizontal/vertical asymmetry is altered at eccentricities larger than 2 degrees in the superior meridian and 2.5 degrees in the inferior meridian. Analysis of hexagon orientations in the central 1.4° of the retina show a tendency for orientation to be locally coherent, with orientation patches consisting of between 35 and 240 cones. PMID:27353225

SITE CHARACTERIZATION AND ANALYSIS PENETROMETER SYSTEM(SCAPS) LAZER-INDUCED FLUORESCENCE (LIF) SENSOR AND SUPPORT SYSTEM

EPA Science Inventory

The Consortium for Site Characterization Technology (CSCT) has established a formal program to accelerate acceptance and application of innovative monitoring and site characterization technologies that improve the way the nation manages its environmental problems. In 1995 the CS...

Image reconstruction from cone-beam projections with attenuation correction

NASA Astrophysics Data System (ADS)

Weng, Yi

1997-07-01

In single photon emission computered tomography (SPECT) imaging, photon attenuation within the body is a major factor contributing to the quantitative inaccuracy in measuring the distribution of radioactivity. Cone-beam SPECT provides improved sensitivity for imaging small organs. This thesis extends the results for 2D parallel- beam and fan-beam geometry to 3D parallel-beam and cone- beam geometries in order to derive filtered backprojection reconstruction algorithms for the 3D exponential parallel-beam transform and for the exponential cone-beam transform with sampling on a sphere. An exact inversion formula for the 3D exponential parallel-beam transform is obtained and is extended to the 3D exponential cone-beam transform. Sampling on a sphere is not useful clinically and current cone-beam tomography, with the focal point traversing a planar orbit, does not acquire sufficient data to give an accurate reconstruction. Thus a data acquisition method that obtains complete data for cone-beam SPECT by simultaneously rotating the gamma camera and translating the patient bed, so that cone-beam projections can be obtained with the focal point traversing a helix that surrounds the patient was developed. First, an implementation of Grangeat's algorithm for helical cone- beam projections was developed without attenuation correction. A fast new rebinning scheme was developed that uses all of the detected data to reconstruct the image and properly normalizes any multiply scanned data. In the case of attenuation no theorem analogous to Tuy's has been proven. We hypothesized that an artifact-free reconstruction could be obtained even if the cone-beam data are attenuated, provided the imaging orbit satisfies Tuy's condition and the exact attenuation map is known. Cone-beam emission data were acquired by using a circle- and-line and a helix orbit on a clinical SPECT system. An iterative conjugate gradient reconstruction algorithm was used to reconstruct projection data with a known attenuation map. The quantitative accuracy of the attenuation-corrected emission reconstruction was significantly improved.

Variability of in situ sediment strength and pore pressure behavior of tidal estuary surface sediments

NASA Astrophysics Data System (ADS)

Lucking, Greg; Stark, Nina; Lippmann, Thomas; Smyth, Stephen

2017-10-01

Tidal estuaries feature spatially and temporally varying sediment dynamics and characteristics. Particularly, the variability of geotechnical sediment parameters is still poorly understood, limiting the prediction of long-term sediment stability and dynamics. This paper presents results from an in situ investigation of surficial sediments (≤50 cm) in a tidal estuary in New Hampshire (USA), using a portable free fall penetrometer. The aim is to investigate variations in sediment strength and pore pressure behavior with regard to sediment type and seabed morphology. The study also provides a detailed analysis of high velocity impact pore pressure data to derive information about sediment type and permeability. The penetrometer was deployed 227 times, and the findings are correlated to 78 sediment samples. Differences in sediment strength and type were found when transitioning from tidal flats to the deeper channels. Finer-grained sediments located predominantly on the tidal flats appeared well consolidated with noticeable and spatially consistent sediment strength (reflected in an estimate of quasi-static bearing capacity qsbcmax 10 kPa). Sediments with higher sand content (>75%) showed more variations in strength relating to differences in gradation, and likely represent loose and poorly consolidated sands (qsbcmax 10-55 kPa). The rate at which the recorded excess pore pressures approached equilibrium after penetration was classified and related to sediment type. The data indicate that the development of excess pore pressures upon impact and during penetration may provide additional insight into the nature and layering of bed material, such as identifying a desiccated or over-consolidated dilative surficial layer. In summary, with varying sediment grain size distributions, bulk densities and morphology, sediment strength and pore pressure behavior can vary significantly within a tidal estuary.

Glass transition temperatures of liquid prepolymers obtained by thermal penetrometry

NASA Technical Reports Server (NTRS)

Potts, J. E., Jr.; Ashcraft, A. C.

1973-01-01

Thermal penetrometry is experimental technique for detecting temperature at which frozen prepolymer becomes soft enough to be pierced by weighted penetrometer needle; temperature at which this occurs is called penetration temperature. Apparatus used to obtain penetration temperatures can be set up largely from standard parts.

Biogeochemical prospecting for uranium with conifers: results from the Midnite Mine area, Washington

USGS Publications Warehouse

Nash, J. Thomas; Ward, Frederick Norville

1977-01-01

The ash of needles, cones, and duff from Ponderosa pine (Pinus ponderosa Laws) growing near uranium deposits of the Midnite mine, Stevens County, Wash., contain as much as 200 parts per million (ppm) uranium. Needle samples containing more than 10 ppm uranium define zones that correlate well with known uranium deposits or dumps. Dispersion is as much as 300 m but generally is less. Background is about 1 ppm. Tree roots are judged to be sampling ore, low-grade uranium halo, or ground water to a depth of about 15 m. Uptake of uranium by Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) needles appears to be about the same as by Ponderosa pine needles. Cones and duff are generally enriched in uranium relate to needles. Needles, cones, and duff are recommended as easily collected, uncomplicated sample media for geochemical surveys. Samples can be analyzed by standard methods and total cost per sample kept to about $6.

Shatter cones at the Keurusselkä impact structure and their relation to local jointing

NASA Astrophysics Data System (ADS)

Hasch, Maximilian; Reimold, Wolf Uwe; Raschke, Ulli; Zaag, Patrice Tristan

2016-08-01

Shatter cones are the only distinct meso- to macroscopic recognition criterion for impact structures, yet not all is known about their formation. The Keurusselkä impact structure, Finland, is interesting in that it presents a multitude of well-exposed shatter cones in medium- to coarse-grained granitoids. The allegedly 27 km wide Keurusselkä impact structure was formed about 1150 Ma ago in rocks of the Central Finland Granitoid Complex. Special attention was paid in this work to possible relationships between shatter cones and local, as well as regionally occurring, fracture or joint systems. A possible shatter cone find outside the previously suggested edge of the structure could mean that the Keurusselkä impact structure is larger than previously thought. The spacing between joints/fractures from regional joint systems was influenced by the impact, but impact-induced fractures strongly follow the regional joint orientation trends. There is a distinct relationship between shatter cones and joints: shatter cones occur on and against joint surfaces of varied orientations and belonging to the regional orientation trends. Planar fractures (PF) and planar deformation features (PDF) were found in three shatter cone samples from the central-most part of the impact structure, whereas other country rock samples from the same level of exposure but further from the assumed center lack shock deformation features. PDF occurrence is enhanced within 5 mm of shatter cone surfaces, which is interpreted to suggest that shock wave reverberation at preimpact joints could be responsible for this local enhancement of shock deformation. Some shatter cone surfaces are coated with a quasi-opaque material which is also found in conspicuous veinlets that branch off from shatter cone surfaces and resemble pseudotachylitic breccia veins. The vein-filling is composed of two mineral phases, one of which could be identified as a montmorillonitic phyllosilicate. The second phase could not be identified yet. The original composition of the fill could not be determined. Further work is required on this material. Observed joints and fractures were discussed against findings from Barringer impact crater. They show that impact-induced joints in the basement rock do not follow impact-specific orientations (such as radial, conical, or concentric).

The Effect of TIMP-1 on the Cone Mosaic in the Retina of the Rat Model of Retinitis Pigmentosa

PubMed Central

Ji, Yerina; Yu, Wan-Qing; Eom, Yun Sung; Bruce, Farouk; Craft, Cheryl Mae; Grzywacz, Norberto M.; Lee, Eun-Jin

2015-01-01

Purpose. The array of photoreceptors found in normal retinas provides uniform and regular sampling of the visual space. In contrast, cones in retinas of the S334ter-line-3 rat model for RP migrate to form a mosaic of rings, leaving large holes with few or no photoreceptors. Similar mosaics appear in human patients with other forms of retinal dystrophy. In the current study, we aimed to investigate the effect of tissue inhibitor of metalloproteinase-1 (TIMP-1) on the mosaic of cones in S334ter-line-3 rat retinas. We focused on TIMP-1 because it is one of the regulators of the extracellular matrix important for cellular migration. Methods. Immunohistochemistry was performed to reveal M-opsin cone cells (M-cone) and the results were quantified to test statistically whether or not TIMP-1 restores the mosaics to normal. In particular, the tests focused on the Voronoi and nearest-neighbor distance analyses. Results. Our tests indicated that TIMP-1 led to significant disruption of the M-opsin cone rings in S334ter-line-3 rat retinas and resulted in almost complete homogeneous mosaics. In addition, TIMP-1 induced the M-cone spatial distribution to become closer to random with decreased regularity in S334ter-line-3 rat retinas. Conclusions. These findings confirm that TIMP-1 induced M-cone mosaics in S334ter-line-3 to gain homogeneity without reaching the degree of regularity seen in normal retinal mosaics. Even if TIMP-1 fails to promote regularity, the effects of this drug on homogeneity appear to be so dramatic that TIMP-1 may be a potential therapeutic agent. TIMP-1 improves sampling of the visual field simply by causing homogeneity. PMID:25515575

Localized atomic segregation in the spalled area of a Zr50Cu40Al10 bulk metallic glasses induced by laser-shock experiment

NASA Astrophysics Data System (ADS)

Jodar, B.; Loison, D.; Yokoyama, Y.; Lescoute, E.; Nivard, M.; Berthe, L.; Sangleboeuf, J.-C.

2018-02-01

Laser-shock experiments were performed on a ternary {Zr50{Cu}40{Al}10} bulk metallic glass. A spalling process was studied through post-mortem analyses conducted on a recovered sample and spall. Scanning electron microscopy magnification of fracture surfaces revealed the presence of a peculiar feature known as cup-cone. Cups are found on sample fracture surface while cones are observed on spall. Two distinct regions can be observed on cups and cones: a smooth viscous-like region in the center and a flat one with large vein-pattern in the periphery. Energy dispersive spectroscopy measurements conducted on these features emphasized atomic distribution discrepancies both on the sample and spall. We propose a mechanism for the initiation and the growth of these features but also a process for atomic segregation during spallation. Cup and cones would originate from cracks arising from shear bands formation (softened paths). These shear bands result from a quadrupolar-shaped atomic disorder engendered around an initiation site by shock wave propagation. This disorder turns into a shear band when tensile front reaches spallation plane. During the separation process, temperature gain induced by shock waves and shear bands generation decreases material viscosity leading to higher atomic mobility. Once in a liquid-like form, atomic clusters migrate and segregate due to inertial effects originating from particle velocity variation (interaction of release waves). As a result, a high rate of copper is found in sample cups and high zirconium concentration is found on spall cones.

Evaluation of AM2 2 1 Lay Pattern Over a 25 CBR Subgrade

DTIC Science & Technology

2018-04-30

penetrometer in shallow pavement applications. Designation : D 6951. West Conshohocken, PA: ASTM International. ____. 2010. Standard test method for...Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO...27 Figure 3.21. Surveying designated cross section

Update of correlations between cone penetration and boring log data.

DOT National Transportation Integrated Search

2008-03-01

The cone penetration test (CPT) has been widely used in Louisiana in the last two decades as an in situ tool to characterize engineering : properties of soils. In addition, conventional drilling and sample retrieval using Shelby tube followed by labo...

Paleoseismologic evidence for large-magnitude (Mw 7.5-8.0) earthquakes on the Ventura blind thrust fault: Implications for multifault ruptures in the Transverse Ranges of southern California

USGS Publications Warehouse

McAuliffe, Lee J.; Dolan, James F.; Rhodes, Edward J.; Hubbard, Judith; Shaw, John H.; Pratt, Thomas L.

2015-01-01

Detailed analysis of continuously cored boreholes and cone penetrometer tests (CPTs), high-resolution seismic-reflection data, and luminescence and 14C dates from Holocene strata folded above the tip of the Ventura blind thrust fault constrain the ages and displacements of the two (or more) most recent earthquakes. These two earthquakes, which are identified by a prominent surface fold scarp and a stratigraphic sequence that thickens across an older buried fold scarp, occurred before the 235-yr-long historic era and after 805 ± 75 yr ago (most recent folding event[s]) and between 4065 and 4665 yr ago (previous folding event[s]). Minimum uplift in these two scarp-forming events was ∼6 m for the most recent earthquake(s) and ∼5.2 m for the previous event(s). Large uplifts such as these typically occur in large-magnitude earthquakes in the range of Mw7.5–8.0. Any such events along the Ventura fault would likely involve rupture of other Transverse Ranges faults to the east and west and/or rupture downward onto the deep, low-angle décollements that underlie these faults. The proximity of this large reverse-fault system to major population centers, including the greater Los Angeles region, and the potential for tsunami generation during ruptures extending offshore along the western parts of the system highlight the importance of understanding the complex behavior of these faults for probabilistic seismic hazard assessment.

Reliability and Agreement Between Metrics of Cone Spacing in Adaptive Optics Images of the Human Retinal Photoreceptor Mosaic.

PubMed

Giannini, Daniela; Lombardo, Giuseppe; Mariotti, Letizia; Devaney, Nicholas; Serrao, Sebastiano; Lombardo, Marco

2017-06-01

To assess reliability and agreement among three metrics used to evaluate the distribution of cell distances in adaptive optics (AO) images of the cone mosaic. Using an AO flood illumination retinal camera, we acquired images of the cone mosaic in 20 healthy subjects and 12 patients with retinal diseases. The three spacing metrics studied were the center-to-center spacing (Scc), the local cone spacing (LCS), and the density recovery profile distance (DRPD). Each metric was calculated in sampling areas of different sizes (64 × 64 μm and 204 × 204 μm) across the parafovea. Both Scc and LCS were able to discriminate between healthy subjects and patients with retinal diseases; DRPD did not reliably detect any abnormality in the distribution of cell distances in patients with retinal diseases. The agreement between Scc and LCS was high in healthy subjects (intraclass correlation coefficient [ICC] ≥ 0.79) and moderate in patients with retinal diseases (ICC ≤ 0.51). The DRPD had poor agreement with Scc (ICC ≤ 0.47) and LCS (ICC ≤ 0.37). The correlation between the spacing metrics of the two sampling areas was greater in healthy subjects than in patients with retinal diseases. The Scc and LCS provided interchangeable estimates of cone distance in AO retinal images of healthy subjects but could not be used interchangeably when investigating retinal diseases with significant cell reflectivity loss (≥30%). The DRPD was unreliable for describing cell distance in a human retinal cone mosaic and did not correlate with Scc and LCS. Caution is needed when comparing spacing metrics evaluated in sampling areas of different sizes.

Development, fabrication and testing of a magnetically connected plastic vacuum probe surface sampler

NASA Technical Reports Server (NTRS)

Phillips, G. B.; Pace, V. A., Jr.

1972-01-01

The sampler utilizes permanent magnets and soft metal pole pieces to connect the cone/filter assembly to the sampling head and vacuum supply. The cone/filter assembly is packaged in a plastic container and presterilized so that the need for any human contact during the sampling procedure is completely eliminated. Microbiological tests have demonstrated that the sampling efficiency is not affected by the magnetic coupling apparatus and that the probe appears to function as efficiently as the conventional plastic and Sandia vacuum probes.

Linear diffusion model dating of cinder cones in Central Anatolia, Turkey

NASA Astrophysics Data System (ADS)

O'Sadnick, L. G.; Reid, M. R.; Cline, M. L.; Cosca, M. A.; Kuscu, G.

2013-12-01

The progressive decrease in slope angle, cone height and cone height/width ratio over time provides the basis for geomorphic dating of cinder cones using linear diffusion models. Previous research using diffusion models to date cinder cones has focused on the cone height/width ratio as the basis for dating cones of unknown age [1,2]. Here we apply linear diffusion models to dating cinder cones. A suite of 16 cinder cones from the Hasandağ volcano area of the Neogene-Quaternary Central Anatolian Volcanic Zone, for which samples are available, were selected for morphologic dating analysis. New 40Ar/39Ar dates for five of these cones range from 62 × 4 to 517 × 9 ka. Linear diffusion models were used to model the erosional degradation of each cone. Diffusion coefficients (κ) for the 5 cinder cones with known ages were constrained by comparing various modeled slope profiles to the current slope profile. The resulting κ is 7.5×0.5 m2kyr-1. Using this κ value, eruption ages were modeled for the remaining 11 cinder cones and range from 53×3 to 455×30 ka. These ages are within the range of ages previously reported for cinder cones in the Hasandağ region. The linear diffusion model-derived ages are being compared to additional new 40Ar/39Ar dates in order to further assess the applicability of morphological dating to constrain the ages of cinder cones. The relatively well-constrained κ value we obtained by applying the linear diffusion model to cinder cones that range in age by nearly 500 ka suggests that this model can be used to date cinder cones. This κ value is higher than the well-established value of κ =3.9 for a cinder cone in a similar climate [3]. Therefore our work confirms the importance of determining appropriate κ values from nearby cones with known ages. References 1. C.A. Wood, J. Volcanol. Geotherm. Res. 8, 137 (1980) 2. D.M. Wood, M.F. Sheridan, J. Volcanol. Geotherm. Res. 83, 241 (1998) 3. J.D. Pelletier, M.L. Cline, Geology 35, 1067 (2007)

Evaluation of 3D airway imaging of obstructive sleep apnea with cone-beam computed tomography.

PubMed

Ogawa, Takumi; Enciso, Reyes; Memon, Ahmed; Mah, James K; Clark, Glenn T

2005-01-01

This study evaluates the use of cone-beam Computer Tomography (CT) for imaging the upper airway structure of Obstructive Sleep Apnea (OSA) patients. The total airway volume and the anteroposterior dimension of oropharyngeal airway showed significant group differences between OSA and gender-matched controls, so if we increase sample size these measurements may distinguish the two groups. We demonstrate the utility of diagnosis of anatomy with the 3D airway imaging with cone-beam Computed Tomography.

Processing Cones: A Computational Structure for Image Analysis.

DTIC Science & Technology

1981-12-01

image analysis applications, referred to as a processing cone, is described and sample algorithms are presented. A fundamental characteristic of the structure is its hierarchical organization into two-dimensional arrays of decreasing resolution. In this architecture, a protypical function is defined on a local window of data and applied uniformly to all windows in a parallel manner. Three basic modes of processing are supported in the cone: reduction operations (upward processing), horizontal operations (processing at a single level) and projection operations (downward

Microcomputed tomography and shock microdeformation studies on shatter cones

NASA Astrophysics Data System (ADS)

Zaag, Patrice Tristan; Reimold, Wolf Uwe; Hipsley, Christy Anna

2016-08-01

One of the aspects of impact cratering that are still not fully understood is the formation of shatter cones and related fracturing phenomena. Yet, shatter cones have been applied as an impact-diagnostic criterion for decades without the role of shock waves and target rock defects in their formation having been elucidated ever. We have tested the application of the nondestructive microcomputed tomography (μCT) method to visualize the interior of shatter cones in order to possibly resolve links between fracture patterns and shatter cone surface features (striations and intervening "valleys"). Shatter-coned samples from different impact sites and in different lithologies were investigated for their μCT suitability, with a shatter cone in sandstone from the Serra da Cangalha impact structure (Brazil) remaining as the most promising candidate because of the fracture resolution achieved. To validate the obtained CT data, the scanned specimen was cut into three orthogonal sets of thin sections. Scans with 13 μm resolution were obtained. μCT scans and microscopic analysis unraveled an orientation of subplanar fractures and related fluid inclusion trails, and planar fracture (PF) orientations in the interior of shatter cones. Planar deformation features (PDF) were observed predominantly near the shatter cone surface. Previously undescribed varieties of feather features (FF), in the form of lamellae emanating from curviplanar and curved fractures, as well as an "arrowhead"-like FF development with microlamellae originating from both sides of a PF, were observed. The timing of shatter cone formation was investigated by establishing temporal relations to the generation of various shock microscopic effects. Shatter cones are, thus, generated post- or syn-formation of PF, FF, subplanar fractures, and PDF. The earliest possible time for shatter cone formation is during the late stage of the compressional phase, that is, shock wave passage, of an impact event.

Paleomagnetic Directions of 3-4ka Basaltic Volcanoes in the Aso Central Cone, Kyushu Japan: Contributions to the Paleosecular Variation and the Volcano-Stratigraphic Studies.

NASA Astrophysics Data System (ADS)

Shibuya, H.; Mochizuki, N.; Miyabuchi, Y.

2017-12-01

In the central cone of Aso volcano, Kyushu Japan, there are 4 basaltic volcanic cones of 3-4 ka in age. The lava flows from those cones spread on the flank of the cones, and they were classified in the relation to each cone. The composition and lithology of those lavas are, however, often difficult to distinguish each other. Thus, we try the magnetostratigraphic study of those lava flows to confirm the classification. The samples were collected from 22 sites, one from a scoria cone and others are from lava, and measured their paleomagnetism. The magnetization of those samples is quite simple, as expected, and alternating field demagnetization well defines the primary component. The site mean directions aligns well on an arc, which defines the paleosecular variation of those ages, 3-4ka. The lava flows and a welded scoria classified as of two centers (Komezuka and Kamikomezuka) are well clustered and confirmed to a single or very closely erupted in time for each center. On the other hand, lava flows related to the other two centers (Ojo and Kijima) have multiple clusters in paleomagnetic directions, and their ages estimated from the paleosecular variation curve interfingers to the classification. It is also very interesting that there seems to be a stagnant point in secular variation just before 3ka, whose direction is similar to the known stagnant point in archeomagnetic secular variation at around 800CE. If there is tendency to stop the SV at the direction, it may be related to the core dynamo processes.

In situ sulfur isotopes (δ(34)S and δ(33)S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS.

PubMed

Fu, Jiali; Hu, Zhaochu; Zhang, Wen; Yang, Lu; Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong

2016-03-10

The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N2 on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4-8 ml min(-1) nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N2 = 4 ml min(-1)). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d90 values of the particles in pressed powder pellets for accurate and precise S isotope analysis should be less than 10 μm. Under the selected optimized analytical conditions, excellent agreements between the determined values and the reference values were achieved for the IAEA-S series standard reference materials and a set of six well-characterized, isotopic homogeneous sulfide standards (PPP-1, MoS2, MASS-1, P-GBW07267, P-GBW07268, P-GBW07270), validating the capability of the developed method for providing high-quality in situ S isotope data in sulfides and elemental sulfur. Copyright © 2016. Published by Elsevier B.V.

Shape measurement and vibration analysis of moving speaker cone

NASA Astrophysics Data System (ADS)

Zhang, Qican; Liu, Yuankun; Lehtonen, Petri

2014-06-01

Surface three-dimensional (3-D) shape information is needed for many fast processes such as structural testing of material, standing waves on loudspeaker cone, etc. Usually measurement is done from limited number of points using electrical sensors or laser distance meters. Fourier Transform Profilometry (FTP) enables fast shape measurement of the whole surface. Method is based on angled sinusoidal fringe pattern projection and image capturing. FTP requires only one image of the deformed fringe pattern to restore the 3-D shape of the measured object, which makes real-time or dynamic data processing possible. In our experiment the method was used for loudspeaker cone distortion measurement in dynamic conditions. For sound quality issues it is important that the whole cone moves in same phase and there are no partial waves. Our imaging resolution was 1280x1024 pixels and frame rate was 200 fps. Using our setup we found unwanted spatial waves in our sample cone.

Annual and Geographic variations in cone production by longleaf pine

Treesearch

William D. Boyer

1987-01-01

Abstract.Cone production by longleaf pine (Pinus palustris Mill.) has been monitored on sample trees in shelterwood stands since 1966. Eleven locations, three each-in Alabama and Florida and one in Louisiana, Mississippi, Georgia, South Carolina, and North Carolina were included in the study. Each location had two test areas, with...

Composition and chemical variability of Corsican Pinus halepensis cone oil.

PubMed

Nam, Anne-Marie; Casanova, Joseph; Tomi, Félix; Bighelli, Ange

2014-09-01

The composition of the essential oil isolated from cones of Pinus halepensis grown in Corsica has been investigated by a combination of chromatographic (CC, GC) and spectroscopic (MS, 13C NMR) techniques. In total, 48 compounds that accounted for 95.5% of the whole composition have been identified. α-Pinene (47.5%) was the major component followed by myrcene (11.0%), (E)-β-caryophyllene (8.3%) and caryophyllene oxide (5.9%). Various diterpenes have been identified by 13C NMR in the fractions of CC. Fifteen oil samples isolated from cones harvested in three forests have been analyzed and two groups of similar importance have been differentiated within the 15 compositions. Oil samples of the first group contained α-pinene (mean 45.0 g/100 g, SD = 5.5) as the major component. The composition of samples of the second group was dominated by myrcene (mean 30.3 g/100g, SD = 9.0) and α-pinene (mean 24.6 g/100 g, SD = 3.1).

Estimation of errors in luminance signals encoded by primate retina resulting from sampling of natural images with red and green cones.

PubMed

Osorio, D; Ruderman, D L; Cronin, T W

1998-01-01

Both long-wavelength-sensitive (L) and medium-wavelength-sensitive (M) cones contribute to luminance mechanisms in human vision. This means that luminance and chromatic signals may be confounded. We use power spectra from natural images to estimate the magnitude of the corruption of luminance signals encoded by an array of retinal ganglion cells resembling the primate magnocellular neurons. The magnitude of this corruption is dependent on the cone lattice and is most severe where cones form clumps of a single spectral type. We find that chromatic corruption may equal or exceed the amplitude of other sources of noise and so could impose constraints on visual performance and on eye design.

Viability of forest floor and canopy seed banks in Pinus contorta var. latifolia (Pinaceae) forests after a mountain pine beetle outbreak.

PubMed

Teste, François P; Lieffers, Victor J; Landhäusser, Simon M

2011-04-01

Seed banks are important for the natural regeneration of many forest species. Most of the seed bank of serotinous lodgepole pine is found in the canopy, but after an outbreak of mountain pine beetle (MPB), a considerable forest-floor seed bank develops through the falling of canopy cones. After large-scale mortality of pine stands from MPB, however, the viability of seeds in both the canopy and the forest-floor cone bank is uncertain. We sampled cones in five stands 3 yr after MPB (3y-MPB); five stands 6 yr after MPB (6y-MPB); and 10 stands 9 yr after MPB (9y-MPB), in central British Columbia, Canada. Seeds were extracted and viability tested using germination techniques. Forest-floor cones had seed with high germination capacity (GC): 82% for embedded (partly buried) closed cones vs. 45% for buried partly open cones. For canopy cones, GC steeply declined about 15 yr after cone maturation and by 25 yr, GC was 50%, compared with 98% in the first year. In the 3y- and 6y-MPB stands, seeds from cones that were 7 to 9 yr old had similar GC on dead and living trees; however, seeds from the dead trees had lower vigor than seeds from living trees. We demonstrate for the first time that a serotinous pine can form a viable soil seed bank by cone burial, which may facilitate natural regeneration if a secondary disturbance occurs. Seeds contained in 15-yr-old cones showed a steep decline in viability, which could limit regeneration if there is a long delay before a secondary disturbance.

Assessing soil compaction on Forest Inventory & Analysis phase 3 field plots using a pocket penetrometer

Treesearch

Michael C. Amacher; Katherine P. O' Neill

2004-01-01

Soil compaction is an important indicator of soil quality, yet few practical methods are available to quantitatively measure this variable. Although an assessment of the areal extent of soil compaction is included as part of the soil indicator portion of the Forest Inventory & Analysis (FIA) program, no quantitative measurement of the degree of soil compaction...

Noise masking of S-cone increments and decrements.

PubMed

Wang, Quanhong; Richters, David P; Eskew, Rhea T

2014-11-12

S-cone increment and decrement detection thresholds were measured in the presence of bipolar, dynamic noise masks. Noise chromaticities were the L-, M-, and S-cone directions, as well as L-M, L+M, and achromatic (L+M+S) directions. Noise contrast power was varied to measure threshold Energy versus Noise (EvN) functions. S+ and S- thresholds were similarly, and weakly, raised by achromatic noise. However, S+ thresholds were much more elevated by S, L+M, L-M, L- and M-cone noises than were S- thresholds, even though the noises consisted of two symmetric chromatic polarities of equal contrast power. A linear cone combination model accounts for the overall pattern of masking of a single test polarity well. L and M cones have opposite signs in their effects upon raising S+ and S- thresholds. The results strongly indicate that the psychophysical mechanisms responsible for S+ and S- detection, presumably based on S-ON and S-OFF pathways, are distinct, unipolar mechanisms, and that they have different spatiotemporal sampling characteristics, or contrast gains, or both. © 2014 ARVO.

A procedure for forecasting western larch seed crops

Treesearch

Arthur L. Roe

1966-01-01

Successful regeneration depends upon good coordination between seed production and seedbed preparation. To aid forest managers in scheduling seedbed preparation, a simple sequential sampling plan for estimating potential cone crops as much as a year in advance of the seed fall was developed and is described herein. With advance knowledge of the cone crop prospects, the...

Pyrolysis kinetics and combustion of thin wood by an advanced cone caorimetry test method

Treesearch

Mark Dietenberger

2012-01-01

Pyrolysis kinetics analysis of extractives, holocellulose, and lignin in the solid redwood over the entire heating regime was possible by specialized cone calorimeter test and new mathematical analysis tools. Added hardware components include: modified sample holder for the thin specimen with tiny thermocouples, the methane ring burner with stainless-steel mesh above...

Layer coefficients for NHDOT pavement materials

NASA Astrophysics Data System (ADS)

Janoo, Vincent C.

1994-09-01

In 1992, the New Hampshire Department of Transportation (NHDOT) experimented with the use of reclaimed asphalt concrete as a base course material, identified by NHDOT as reclaimed stabilized base (RSB). The RSB and a control test section were placed on Interstate 93 between exits 18 and 19. The RSB test section was designed to the same structural number (SN) as the control. To evaluate the structural capacity of these test sections, the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) conducted deflection tests using a Dynatest 8000 falling weight deflectometer (FWD). Preliminary analysis of the results by NHDOT personnel showed higher deflection in the reclaimed asphalt concrete test sections. The explanation was that the layer coefficient used for the RSB layer in the design was probably incorrect. A total of 10 test sections constituting the base course materials used by NHDOT were built near Bow, New Hampshire. CRREL evaluated and estimated the layer coefficients of the base course materials. The test program was developed to characterize the material in more than one way. Tests were conducted with the heavy weight deflectometer (HWD), dynamic cone penetrometer (DCP) and the Clegg hammer. In situ California bearing ratio (CBR) tests were also conducted. The deflection from the HWD were used with the WESDEF back calculation program to determine the layer moduli. The moduli were than used with the AASHTO Design Guide to calculate the layer coefficients. The layer coefficients were also determined with the method proposed by Rohde. The CBR values from the Clegg hammer, in situ CBR and DCP tests were also used in the relationships in the HDM model to determine the layer coefficients.

Determining the geotechnical properties of planetary regolith using Low Velocity Penetrometers

NASA Astrophysics Data System (ADS)

Seweryn, K.; Skocki, K.; Banaszkiewicz, M.; Grygorczuk, J.; Kolano, M.; Kuciński, T.; Mazurek, J.; Morawski, M.; Białek, A.; Rickman, H.; Wawrzaszek, R.

2014-09-01

Measurements of mechanical and thermophysical properties of planetary surface allow determining many important parameters useful for planetologists. For example, effective heat conductivity or thermal inertia of the regolith can help to better understand the processes occurring in the bodies interior. Chemical and mineralogical composition gives us a chance to determine the origin and evolution of moons and satellites. Mechanical properties of the surface are one of the key factors needed by civil engineers for developing future bases on space bodies. Space missions to planetary bodies highly restrict the payload concerning its mass and power consumption. Therefore, it is quite impossible to use a standard terrestrial technique like the Load Plate Test or Direct Shear Tests to determine the geotechnical parameters of the planetary regolith. Even the Dynamic Cone Penetration (DCP) method, which is frequently used for field testing, does not fit well with the constraints imposed by a space mission. Nevertheless, its operation principle is very similar to that of at the Low Velocity Penetrators (LVP), several of them being currently on their way to planetary bodies (e.g. the MUPUS instrument) or which were developed in the last couple of years (e.g. the CHOMIK instrument or the KRET device). In this paper we present a comparison between DCP method and LVP operation which was observed during several tests campaigns during mole KRET and CHOMIK instrument development. The tests were performed in different planetary analogues: JSC-1A, Chenobi and AGK-2010, Phobos analogue, cometary analogues F1, F2 and F3 (SRC) and dry quartz sand. In the last part of the paper the concept of results' interpretation is presented.

Development and Testing of an ISRU Soil Mechanics Vacuum Test Facility

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie E.; Wilkinson, R. Allen

2014-01-01

For extraterrestrial missions, earth based testing in relevant environments is key to successful hardware development. This is true for both early component level development and system level integration. For In-Situ Resource Utilization (ISRU) on the moon, hardware must interface with the surface material, or regolith, in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, properly conditioned bed of lunar regolith simulant. However, in earth-based granular media, such as lunar regolith simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. A mid-size chamber (3.66 m tall, 1.5 m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64 m deep by 0.914 m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types were used. Data obtained from an electric cone penetrometer can be used to determine strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off-gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5 Torr, regardless of the pump rate. The slow off-gassing of the soil at low pressure lead to long test times; a full week to reach 10(exp -5) Torr. Robotic soil manipulation would enable multiple ISRU hardware test within the same vacuum cycle. The feasibility of a robotically controlled auger and tamper was explored at vacuum conditions.

ISRU Soil Mechanics Vacuum Facility: Soil Bin Preparation and Simulant Strength Characterization

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie; Wilkinson, Allen

2012-01-01

Testing in relevant environments is key to exploration mission hardware development. This is true on both the component level (in early development) and system level (in late development stages). During ISRU missions the hardware will interface with the soil (digging, roving, etc) in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, conditioned simulant bed. However, in earth-based granular media, such as lunar soil simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. The Vacuum Facility #13, a mid-size chamber (3.66m tall, 1.5m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64m deep by 0.914m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types have been used. An electric cone penetrometer was used to measure simulant strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5Torr, regardless of the pump rate. However, slow off gassing of the soil lead to long test times, a full week, to reach 10-5Torr. This work highlights the need for robotic machine-simulant hardware and operations in vacuum to expeditiously perform (sub-)systems tests.

Predicting hydrofacies and hydraulic conductivity from direct-push data using a data-driven relevance vector machine approach: Motivations, algorithms, and application

NASA Astrophysics Data System (ADS)

Paradis, Daniel; Lefebvre, René; Gloaguen, Erwan; Rivera, Alfonso

2015-01-01

The spatial heterogeneity of hydraulic conductivity (K) exerts a major control on groundwater flow and solute transport. The heterogeneous spatial distribution of K can be imaged using indirect geophysical data as long as reliable relations exist to link geophysical data to K. This paper presents a nonparametric learning machine approach to predict aquifer K from cone penetrometer tests (CPT) coupled with a soil moisture and resistivity probe (SMR) using relevance vector machines (RVMs). The learning machine approach is demonstrated with an application to a heterogeneous unconsolidated littoral aquifer in a 12 km2 subwatershed, where relations between K and multiparameters CPT/SMR soundings appear complex. Our approach involved fuzzy clustering to define hydrofacies (HF) on the basis of CPT/SMR and K data prior to the training of RVMs for HFs recognition and K prediction on the basis of CPT/SMR data alone. The learning machine was built from a colocated training data set representative of the study area that includes K data from slug tests and CPT/SMR data up-scaled at a common vertical resolution of 15 cm with K data. After training, the predictive capabilities of the learning machine were assessed through cross validation with data withheld from the training data set and with K data from flowmeter tests not used during the training process. Results show that HF and K predictions from the learning machine are consistent with hydraulic tests. The combined use of CPT/SMR data and RVM-based learning machine proved to be powerful and efficient for the characterization of high-resolution K heterogeneity for unconsolidated aquifers.

Using Advanced Tensiometers to Monitor Temporal Variations in Pore Pressure

NASA Astrophysics Data System (ADS)

Nichols, R. L.; Young, M. H.; Dixon, K. L.; Rossabi, J.; Hyde, W. K.; Holmes-Burns, H.

2002-12-01

The Savannah River Site has installed a comprehensive vadose zone monitoring system (VZMS) at it's low level radioactive waste disposal facility to collect the necessary information to calculate contaminant flux. The VZMS includes water content reflectometers, suction lysimeters, advanced tensiometers (ATs), water flux meters, access ports for neutron probes, and a tipping bucket rain gauge. Forty one ATs were installed from 1999 to 2001 at depths ranging from 2 to 60 feet and have been operated continuously. The installation depths were based on a hydrostatigraphic model developed from core logs, cone penetrometer logs, moisture content profiles, water retention curves model that were obtained during the phased installation of the VZMS. An AT consists of a porous cup installed at a prescribed depth with casing back to the surface and a pressure transducer that is lowered into the casing and connects with the porous cup. The pressure transducer transmits it's signal to a datalogger where the data is stored for future retrieval using a cellular phone communications package. Results from the 2 year operating period show that the AT calibrations are stable and t ATs are capable of extended monitoring of pore pressures in the 0 to 300 cm H2 O range. The ATs had sufficient resolution to detect the naturally occurring fluctuations in pore pressure (1 to 100 cm H2 O over 1 to 72 hours) that resulted from infiltration events at the site. The stable performance of the ATs combined with their ability to detect naturally occurring fluctuations in pore pressure make the ATs a useful tool in measuring temporal pore pressure variations for use in calibrating numerical models of fluid flow in variably saturated porous media.

Computer program for calculating supersonic flow about circular, elliptic, and bielliptic cones by the method of lines

NASA Technical Reports Server (NTRS)

Klunker, E. B.; South, J. C., Jr.; Davis, R. M.

1972-01-01

A user's manual for a computer program which calculates the supersonic flow about circular, elliptic, and bielliptic cones at incidence and elliptic cones at yaw by the method of lines is presented. The program is automated to compute a case from known or easily calculated solution by changing the parameters through a sequence of steps. It provides information including the shock shape, flow field, isentropic surface properties, entropy layer, and force coefficients. A description of the program operation, sample computations, and a FORTRAN 4 listing are presented.

Scattering rings in optically anisotropic porous silicon

NASA Astrophysics Data System (ADS)

Oton, C. J.; Gaburro, Z.; Ghulinyan, M.; Pancheri, L.; Bettotti, P.; Negro, L. Dal; Pavesi, L.

2002-12-01

We report the observation of strongly anisotropic scattering of laser light at oblique incidence on a (100)-oriented porous silicon layer. The scattered light forms cones tangent to the incident and reflected beams. The conical pattern is caused by scattering on the vertical walls of pores, which are straight along the layer thickness. The light cone defines structured light rings onto a screen normal to the cone axis. We explain the various structures by optical anisotropy of porous silicon. For the sample under analysis, we directly measure from the ring patterns a value of Δn/nord=8% of positive birefringence.

Sedimentology, eruptive mechanism and facies architecture of basaltic scoria cones from the Auckland Volcanic Field (New Zealand)

NASA Astrophysics Data System (ADS)

Kereszturi, Gábor; Németh, Károly

2016-09-01

Scoria cones are a common type of basaltic to andesitic small-volume volcanoes (e.g. 10- 1-10- 5 km3) that results from gas-bubble driven explosive eruptive styles. Although they are small in volume, they can produce complex eruptions, involving multiple eruptive styles. Eight scoria cones from the Quaternary Auckland Volcanic Field in New Zealand were selected to define the eruptive style variability from their volcanic facies architecture. The reconstruction of their eruptive and pyroclastic transport mechanisms was established on the basis of study of their volcanic sedimentology, stratigraphy, and measurement of their pyroclast density, porosity, Scanning Electron Microscopy, 2D particle morphology analysis and Visible and Near Visible Infrared Spectroscopy. Collection of these data allowed defining three end-member types of scoria cones inferred to be constructed from lava-fountaining, transitional fountaining and Strombolian type, and explosive Strombolian type. Using the physical and field-based characteristics of scoriaceous samples a simple generalised facies model of basaltic scoria cones for the AVF is developed that can be extended to other scoria cones elsewhere. The typical AVF scoria cone has an initial phreatomagmatic phases that might reduce the volume of magma available for subsequent scoria cone forming eruptions. This inferred to have the main reason to have decreased cone volumes recognised from Auckland in comparison to other volcanic fields evolved dominantly in dry eruptive condition (e.g. no external water influence). It suggests that such subtle eruptive style variations through a scoria cone evolution need to be integrated into the hazard assessment of a potentially active volcanic field such as that in Auckland.

ON Cone Bipolar Cell Axonal Synapses in the OFF Inner Plexiform Layer of the Rabbit Retina

PubMed Central

Lauritzen, J. Scott; Anderson, James R.; Jones, Bryan W.; Watt, Carl B.; Mohammed, Shoeb; Hoang, John V.; Marc, Robert E.

2012-01-01

Analysis of the rabbit retinal connectome RC1 reveals that the division between the ON and OFF inner plexiform layer (IPL) is not structurally absolute. ON cone bipolar cells make non-canonical axonal synapses onto specific targets and receive amacrine cell synapses in the nominal OFF layer, creating novel motifs, including inhibitory crossover networks. Automated transmission electron microscope (ATEM) imaging, molecular tagging, tracing, and rendering of ≈ 400 bipolar cells reveals axonal ribbons in 36% of ON cone bipolar cells, throughout the OFF IPL. The targets include GABA-positive amacrine cells (γACs), glycine-positive amacrine cells (GACs) and ganglion cells. Most ON cone bipolar cell axonal contacts target GACs driven by OFF cone bipolar cells, forming new architectures for generating ON-OFF amacrine cells. Many of these ON-OFF GACs target ON cone bipolar cell axons, ON γACs and/or ON-OFF ganglion cells, representing widespread mechanisms for OFF to ON crossover inhibition. Other targets include OFF γACs presynaptic to OFF bipolar cells, forming γAC-mediated crossover motifs. ON cone bipolar cell axonal ribbons drive bistratified ON-OFF ganglion cells in the OFF layer and provide ON drive to polarity-appropriate targets such as bistratified diving ganglion cells (bsdGCs). The targeting precision of ON cone bipolar cell axonal synapses shows that this drive incidence is necessarily a joint distribution of cone bipolar cell axonal frequency and target cell trajectories through a given volume of the OFF layer. Such joint distribution sampling is likely common when targets are sparser than sources and when sources are coupled, as are ON cone bipolar cells. PMID:23042441

Directional view interpolation for compensation of sparse angular sampling in cone-beam CT.

PubMed

Bertram, Matthias; Wiegert, Jens; Schafer, Dirk; Aach, Til; Rose, Georg

2009-07-01

In flat detector cone-beam computed tomography and related applications, sparse angular sampling frequently leads to characteristic streak artifacts. To overcome this problem, it has been suggested to generate additional views by means of interpolation. The practicality of this approach is investigated in combination with a dedicated method for angular interpolation of 3-D sinogram data. For this purpose, a novel dedicated shape-driven directional interpolation algorithm based on a structure tensor approach is developed. Quantitative evaluation shows that this method clearly outperforms conventional scene-based interpolation schemes. Furthermore, the image quality trade-offs associated with the use of interpolated intermediate views are systematically evaluated for simulated and clinical cone-beam computed tomography data sets of the human head. It is found that utilization of directionally interpolated views significantly reduces streak artifacts and noise, at the expense of small introduced image blur.

Coherent backscattering of light by an inhomogeneous cloud of cold atoms

NASA Astrophysics Data System (ADS)

Labeyrie, Guillaume; Delande, Dominique; Müller, Cord A.; Miniatura, Christian; Kaiser, Robin

2003-03-01

When a quasiresonant laser beam illuminates an optically thick cloud of laser-cooled rubidium atoms, the average diffuse intensity reflected off the sample is enhanced in a narrow angular range around the direction of exact backscattering. This phenomenon is known as coherent backscattering (CBS). By detuning the laser from resonance, we are able to modify the light scattering mean-free path inside the sample and we record accordingly the variations of the CBS cone shape. We then compare the experimental data with theoretical calculations and Monte Carlo simulations including the effect of the light polarization and of the internal structure of the atoms. We confirm that the internal structure strongly affects the enhancement factor of the cone and we show that the unusual shape of the atomic medium—approximately a spherically-symmetric, Gaussian density profile—strongly affects the width and shape of the cone.

Aging of human short-wave cone pathways

PubMed Central

Shinomori, Keizo; Werner, John S.

2012-01-01

The retinal image is sampled concurrently, and largely independently, by three physiologically and anatomically distinct pathways, each with separate ON and OFF subdivisions. The retinal circuitry giving rise to an ON pathway receiving input from the short-wave-sensitive (S) cones is well understood, but the S-cone OFF circuitry is more controversial. Here, we characterize the temporal properties of putative S-cone ON and OFF pathways in younger and older observers by measuring thresholds for stimuli that produce increases or decreases in S-cone stimulation, while the middle- and long-wave-sensitive cones are unmodulated. We characterize the data in terms of an impulse response function, the theoretical response to a flash of infinitely short duration, from which the response to any temporally varying stimulus may be predicted. Results show that the S-cone response to increments is faster than to decrements, but this difference is significantly greater for older individuals. The impulse response function amplitudes for increment and decrement responses are highly correlated across individuals, whereas the timing is not. This strongly suggests that the amplitude is controlled by neural circuitry that is common to S-cone ON and OFF responses (photoreceptors), whereas the timing is controlled by separate postreceptoral pathways. The slower response of the putative OFF pathway is ascribed to different retinal circuitry, possibly attributable to a sign-inverting amacrine cell not present in the ON pathway. It is significant that this pathway is affected selectively in the elderly by becoming slower, whereas the temporal properties of the S-cone ON response are stable across the life span of an individual. PMID:22847416

Dynamic Recrystallization Kinetics of 690 Alloy During Hot Compression of Double-Cone Samples

NASA Astrophysics Data System (ADS)

Wang, Jue; Zhai, Shun-Chao

2017-03-01

Hot compression tests of double-cone samples were conducted for 690 alloy to study the kinetic behavior of the complete dynamic recrystallization (DRX) process under low deformation temperatures from 960 to 1080 °C. The microstructure of 82 points in the vertical section of every deformed sample was quantitatively analyzed to determine the DRX fraction. Corresponding strain of these points was calculated by finite element simulations. Kinetic curves of the specimens with different preheating temperatures were then constructed. The features of various boundaries with different misorientation angles were investigated by electron backscatter diffraction technology and transmission electron microscope. The results showed that the strain is continuously and symmetrically distributed along the centerline of the vertical section. Large strain of 1.84 was obtained when the compression amount is 12 mm for double-cone samples. All the fitted kinetic curves display an "S" type, which possess a low growth rate of DRX at the beginning and the end of compression. The critical strain of recrystallization decreases with the increase in preheating temperature, while the completion strain remains around 1.5 for all the samples. The initial and maximum growth rates of DRX fraction have the opposite trend with the change in temperature, which is considered to be attributed to the behaviors of different misorientation boundaries.

Bottom Characterization with High Resolution Sonar Data and Geochemical Analyses of an Uninvestigated Cone in Lagoa das Furnas on São Miguel Island, Azores Archipelago

NASA Astrophysics Data System (ADS)

Andersson, T.

2015-12-01

Lagoa das Furnas is a crater lake located in an area exposed to geohazards from earthquakes and volcanic activity on the island São Miguel in the Azores Archipelago. The Furnas volcanic center has a long history of earthquakes and volcanic activity. The area is relatively well studied except for the lake floor. Therefore, a high resolution geophysical and geological mapping survey was conducted at Lagoa das Furnas. Sidescan sonar was used to map the surface of the lake floor and single beam sonar was used to acquire sub-bottom profiles. In addition to the geophysical mapping, sediment surface sampling and core drilling were carried out followed by geochemical analyses of the retrieved material. The mapped data permitted a characterization of the floor of Lagoa das Furnas and revealed several volcanic features including fumarolic activity and a previously uninvestigated volcanic cone in the southern part of the lake. In order to unravel the origin of this cone several methods were applied, including analyses of tephra and minerals collected from the cone itself and from nearby deposits of two known eruptions, Furnas I and Furnas 1630. Sedimentological, petrological, geochemical and geochronological studies of pyroclastic deposits from the cone suggest a subaqueous eruption linked to the Furnas 1630 eruption. The chemistry of glass and crystal fragments sampled from the cone suggests that it is composed of more evolved magma than that of the main Furnas 1630, implying that the lake cone is likely a product of the last eruptional phase. According to historical records, two of three lakes were lost due the Furnas 1630 eruption. The results of this study show that the remaining lake is most likely Lagoa das Furnas, which consequently must have existed before the 1630 eruption.

ORACLE INEQUALITIES FOR THE LASSO IN THE COX MODEL

PubMed Central

Huang, Jian; Sun, Tingni; Ying, Zhiliang; Yu, Yi; Zhang, Cun-Hui

2013-01-01

We study the absolute penalized maximum partial likelihood estimator in sparse, high-dimensional Cox proportional hazards regression models where the number of time-dependent covariates can be larger than the sample size. We establish oracle inequalities based on natural extensions of the compatibility and cone invertibility factors of the Hessian matrix at the true regression coefficients. Similar results based on an extension of the restricted eigenvalue can be also proved by our method. However, the presented oracle inequalities are sharper since the compatibility and cone invertibility factors are always greater than the corresponding restricted eigenvalue. In the Cox regression model, the Hessian matrix is based on time-dependent covariates in censored risk sets, so that the compatibility and cone invertibility factors, and the restricted eigenvalue as well, are random variables even when they are evaluated for the Hessian at the true regression coefficients. Under mild conditions, we prove that these quantities are bounded from below by positive constants for time-dependent covariates, including cases where the number of covariates is of greater order than the sample size. Consequently, the compatibility and cone invertibility factors can be treated as positive constants in our oracle inequalities. PMID:24086091

ORACLE INEQUALITIES FOR THE LASSO IN THE COX MODEL.

PubMed

Huang, Jian; Sun, Tingni; Ying, Zhiliang; Yu, Yi; Zhang, Cun-Hui

2013-06-01

We study the absolute penalized maximum partial likelihood estimator in sparse, high-dimensional Cox proportional hazards regression models where the number of time-dependent covariates can be larger than the sample size. We establish oracle inequalities based on natural extensions of the compatibility and cone invertibility factors of the Hessian matrix at the true regression coefficients. Similar results based on an extension of the restricted eigenvalue can be also proved by our method. However, the presented oracle inequalities are sharper since the compatibility and cone invertibility factors are always greater than the corresponding restricted eigenvalue. In the Cox regression model, the Hessian matrix is based on time-dependent covariates in censored risk sets, so that the compatibility and cone invertibility factors, and the restricted eigenvalue as well, are random variables even when they are evaluated for the Hessian at the true regression coefficients. Under mild conditions, we prove that these quantities are bounded from below by positive constants for time-dependent covariates, including cases where the number of covariates is of greater order than the sample size. Consequently, the compatibility and cone invertibility factors can be treated as positive constants in our oracle inequalities.

Antimicrobial effect of three disinfecting agents on Resilon cones and their effect on surface topography: An in vitro study.

PubMed

Chandrappa, Mahesh Martur; Meharwade, Prasanna Mahadevasa; Srinivasan, Raghu; Bhandary, Shreetha; Nasreen, Farhat

2016-01-01

The objective of this study was to evaluate the effectiveness of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and 2% peracetic acid (PAA) in disinfecting Resilon cones and to evaluate topographical changes microscopically under scanning electron microscope (SEM) after rapid chemical disinfection. Resilon cones were disinfected in an ultraviolet (UV) light chamber for 20 min and contaminated by immersing in a microbial suspension of Enterococcus faecalis for 30 min. The contaminated cones were then immersed in the 5.25% NaOCl, 2% CHX, and 2% PAA for 1 min, 5 min, and 10 min, separately. The cones were then incubated at 37°C in thioglycollate broth for 7 days and examined for turbidity. The samples showing turbidity were subcultured on blood agar and incubated at 37°C for 48 h. Gram staining was done to confirm that the cultured bacteria were E. faecalis. Surface changes of disinfected Resilon cones were evaluated under SEM. The data were analyzed statistically using Kruskal-Wallis, analysis of variance (ANOVA), and Mann-Whitney U-test. In eliminating E. faecalis, 5.25% NaOCl was most effective followed by 2% PAA and 2% CHX. Topographic examination of tested Resilon cones revealed some surface deposits after disinfection with 5.25% NaOCl and 2% CHX, whereas 2% PAA caused surface erosion. In disinfecting Resilon cones, 5.25% NaOCl is most effective followed by 2% PAA and 2% CHX.

Nonlinear flow affects hydrodynamic forces and neutrophil adhesion rates in cone-plate viscometers.

PubMed Central

Shankaran, H; Neelamegham, S

2001-01-01

We present a theoretical and experimental analysis of the effects of nonlinear flow in a cone-plate viscometer. The analysis predicts that flow in the viscometer is a function of two parameters, the Reynolds number and the cone angle. Nonlinear flow occurs at high shear rates and causes spatial variations in wall shear stress, collision frequency, interparticle forces and attachment times within the viscometer. We examined the effect of these features on cellular adhesion kinetics. Based on recent data (Taylor, A. D., S. Neelamegham, J. D. Hellums, et al. 1996. Biophys. J. 71:3488-3500), we modeled neutrophil homotypic aggregation as a process that is integrin-limited at low shear and selectin-limited at high shear. Our calculations suggest that selectin and integrin on-rates lie in the order of 10(-2)-10(-4)/s. They also indicate that secondary flow causes positional variations in adhesion efficiency in the viscometer, and that the overall efficiency is dependent not only on the shear rate, but also the sample volume and the cone angle. Experiments performed with isolated neutrophils confirmed these predictions. In these experiments, enhancing secondary flow by increasing the sample volume from 100 to 1000 microl at 1500/s for a 2 degrees cone caused up to an approximately 45% drop in adhesion efficiency. Our results suggest that secondary flow may significantly influence cellular aggregation, platelet activation, and endothelial cell mechanotransduction measurements made in the viscometer over the range of conditions applied in typical biological studies. PMID:11371440

Bulk density and soil resistance to penetration as affected by commercial thinning in northeastern Washington.

Treesearch

Johanna D. Landsberg; Richard E. Miller; Harry W. Anderson; Jeffrey S. Tepp

2003-01-01

Bulk density and soil resistance to penetration were measured in ten, 3- to 11-ha operational units in overstocked, mixed-conifer stands in northeast Washington. Resistance was measured with a recording penetrometer to the 33-cm depth (13 in) at 10 stations on each of 8 to 17, 30.5-m-long, randomly located transects in each unit. Subsequently, different combinations of...

Combustion characteristics of north-eastern USA vegetation tested in the cone calorimeter: invasive versus non-invasive plants

Treesearch

Alison C. Dibble; Robert H. White; Patricia K. Lebow

2007-01-01

In the north-eastern United States, invasive plants alter forest fuels, but their combustion characteristics are largely unknown. We assessed unground samples of foliage and twigs in the cone calorimeter for 21 non-invasive, native species, paired with 21 invasive species (18 non-native). Variables included sustained ignition, peak heat release rate, total heat release...

Cone beam x-ray luminescence computed tomography: a feasibility study.

PubMed

Chen, Dongmei; Zhu, Shouping; Yi, Huangjian; Zhang, Xianghan; Chen, Duofang; Liang, Jimin; Tian, Jie

2013-03-01

The appearance of x-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging by x ray. In the previous XLCT system, the sample was irradiated by a sequence of narrow x-ray beams and the x-ray luminescence was measured by a highly sensitive charge coupled device (CCD) camera. This resulted in a relatively long sampling time and relatively low utilization of the x-ray beam. In this paper, a novel cone beam x-ray luminescence computed tomography strategy is proposed, which can fully utilize the x-ray dose and shorten the scanning time. The imaging model and reconstruction method are described. The validity of the imaging strategy has been studied in this paper. In the cone beam XLCT system, the cone beam x ray was adopted to illuminate the sample and a highly sensitive CCD camera was utilized to acquire luminescent photons emitted from the sample. Photons scattering in biological tissues makes it an ill-posed problem to reconstruct the 3D distribution of the x-ray luminescent sample in the cone beam XLCT. In order to overcome this issue, the authors used the diffusion approximation model to describe the photon propagation in tissues, and employed the sparse regularization method for reconstruction. An incomplete variables truncated conjugate gradient method and permissible region strategy were used for reconstruction. Meanwhile, traditional x-ray CT imaging could also be performed in this system. The x-ray attenuation effect has been considered in their imaging model, which is helpful in improving the reconstruction accuracy. First, simulation experiments with cylinder phantoms were carried out to illustrate the validity of the proposed compensated method. The experimental results showed that the location error of the compensated algorithm was smaller than that of the uncompensated method. The permissible region strategy was applied and reduced the reconstruction error to less than 2 mm. The robustness and stability were then evaluated from different view numbers, different regularization parameters, different measurement noise levels, and optical parameters mismatch. The reconstruction results showed that the settings had a small effect on the reconstruction. The nonhomogeneous phantom simulation was also carried out to simulate a more complex experimental situation and evaluated their proposed method. Second, the physical cylinder phantom experiments further showed similar results in their prototype XLCT system. With the discussion of the above experiments, it was shown that the proposed method is feasible to the general case and actual experiments. Utilizing numerical simulation and physical experiments, the authors demonstrated the validity of the new cone beam XLCT method. Furthermore, compared with the previous narrow beam XLCT, the cone beam XLCT could more fully utilize the x-ray dose and the scanning time would be shortened greatly. The study of both simulation experiments and physical phantom experiments indicated that the proposed method was feasible to the general case and actual experiments.

New quantitative, in-situ characterization of weathering in geomaterials.

NASA Astrophysics Data System (ADS)

Scrivano, Simona; Gaggero, Laura; Gisbert Aguilar, Josep; Yus Gonzalez, Adrian

2016-04-01

The mineralogical and microtextural analyses of weathered rocks and mortars are the main diagnostic tools to address the materials exposed under different environmental conditions in order to enucleate and mitigate the decay factors. The characterization of weathering intensity is mostly descriptive and non-quantitative (ICOMOS Glossary, 2008); the Fitzner indexes in arenites (Fitzner et al., 2002) and more recently applied to marbles (Scrivano et al., 2013) provide an operator dependent method. The current diagnostic of decay (Drdàcky & Slìzkovà, 2014) based on a scotch tape tearing off the surface was improved by a specifically adapted pocket penetrometer, and a joint gravimetric + minero-chemical analysis under SEM of ablational decay products. The steps are the following: i) Preparation of stubs for SEM with adherent conductive carbon tape (surface area 1.3 cm2) ii) Weighing of stub + tape + its plastic envelope at 0.001 g precision iii) Connecting the stub to a pocket penetrometer iv) Non invasive sampling of the incoherent dust applying a constant pressure of 2 kgf for 1 minute, and then packing away the stub without loosing grains v) Weighing of stub + tape + weathering products + their plastic envelope at 0.001 g precision vi) Recast the weight of removed material vii) Addressing the weathering products to SEM - EDS. Our quantitative peeling test was applied on a 96m long cladded wall in the Staglieno Monumental Cemetery in Genoa. The wall shows weathering gradients due to a neighbouring interred stream and to different insulation. Slabs of ophicalcite marble were tested from three different areas (5 samples were collected to the E, 5 samples at the centre, 5 samples to the W). The results highlighted capillary rise up to 2 meters height and a more weathered central area. On the whole, our protocol allows a delicate, virtually not impacting and reproducible factual sampling. Moreover, if carried out on a statistically significant population, the decay intensity results are defined and categorized. Drdàcky M. & Slìzkovà Z., 2014. In situ peeling tests for assessing the cohesion and consolidation characteristics of historic plasters and render surfaces. Studies in conservation, vol 0. Fitzner B. & Heinrichs K., 2002. Damage diagnosis on stone monuments weathering forms, damage categories and damage indices. - In: Prikryl R. and Viles H.A. (eds.): Understanding and managing stone decay. - Proceedings Internat. Conf. "Stone weathering and atmospheric pollution network (SWAPNET)": 11-56, Charles Univ. Prague (Karolinum Press). ICOMOS.ISCS, 2008 Illustrated glossary on stone deterioration patterns, 78 pp. Scrivano S., Gaggero L. & Taddei A., 2013. Alteration patterns of marble under different environmental exposures: a systematic approach from the Staglieno Monumental cemetery and museum collections in Genoa (Italy). In: Proceedings of the 12th International Congress on Deterioration and Conservation of Stone, New York, 22-26 October 2012. In press.

Color discrimination in carriers of color deficiency.

PubMed

Hood, S M; Mollon, J D; Purves, L; Jordan, G

2006-09-01

Carriers of X-linked color vision deficiencies have previously been reported to exhibit mild abnormalities of color matching and discrimination. In a sample of 55 carriers of protan and deutan deficiencies and 55 age-matched normal controls, we measured chromatic discrimination along a red-green axis. We found that discrimination was impaired in the case of carriers of deutan deficiencies (which affect the middle-wave-sensitive cones of the retina), but was normal in the case of carriers of protan deficiencies (which affect the long-wave-sensitive cones). We argue that this result can be explained by the difference in the relative numbers of middle- and long-wave cones in heterozygous retinae: the imbalance of the two cone types is predicted to be much greater in the case of the deutan heterozygote than in the case of the protan heterozygote. In future studies it will be necessary to consider separately the two types of heterozygote.

Regularization of the light-cone gauge gluon propagator singularities using sub-gauge conditions

DOE PAGES

Chirilli, Giovanni A.; Kovchegov, Yuri V.; Wertepny, Douglas E.

2015-12-21

Perturbative QCD calculations in the light-cone gauge have long suffered from the ambiguity associated with the regularization of the poles in the gluon propagator. In this work we study sub-gauge conditions within the light-cone gauge corresponding to several known ways of regulating the gluon propagator. By using the functional integral calculation of the gluon propagator, we rederive the known sub-gauge conditions for the θ-function gauges and identify the sub-gauge condition for the principal value (PV) regularization of the gluon propagator’s light-cone poles. The obtained sub-gauge condition for the PV case is further verified by a sample calculation of the classicalmore » Yang-Mills field of two collinear ultrarelativistic point color charges. Our method does not allow one to construct a sub-gauge condition corresponding to the well-known Mandelstam-Leibbrandt prescription for regulating the gluon propagator poles.« less

Antimicrobial effect of three disinfecting agents on Resilon cones and their effect on surface topography: An in vitro study

PubMed Central

Chandrappa, Mahesh Martur; Meharwade, Prasanna Mahadevasa; Srinivasan, Raghu; Bhandary, Shreetha; Nasreen, Farhat

2016-01-01

Aim: The objective of this study was to evaluate the effectiveness of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and 2% peracetic acid (PAA) in disinfecting Resilon cones and to evaluate topographical changes microscopically under scanning electron microscope (SEM) after rapid chemical disinfection. Materials and Methods: Resilon cones were disinfected in an ultraviolet (UV) light chamber for 20 min and contaminated by immersing in a microbial suspension of Enterococcus faecalis for 30 min. The contaminated cones were then immersed in the 5.25% NaOCl, 2% CHX, and 2% PAA for 1 min, 5 min, and 10 min, separately. The cones were then incubated at 37°C in thioglycollate broth for 7 days and examined for turbidity. The samples showing turbidity were subcultured on blood agar and incubated at 37°C for 48 h. Gram staining was done to confirm that the cultured bacteria were E. faecalis. Surface changes of disinfected Resilon cones were evaluated under SEM. Statistical Analysis Used: The data were analyzed statistically using Kruskal-Wallis, analysis of variance (ANOVA), and Mann–Whitney U-test. Result: In eliminating E. faecalis, 5.25% NaOCl was most effective followed by 2% PAA and 2% CHX. Topographic examination of tested Resilon cones revealed some surface deposits after disinfection with 5.25% NaOCl and 2% CHX, whereas 2% PAA caused surface erosion. Conclusion: In disinfecting Resilon cones, 5.25% NaOCl is most effective followed by 2% PAA and 2% CHX. PMID:27099418

Continuous shear rheometry of o/w emulsions; control of evaporation in cone/plate geometry.

PubMed

Orafidiya, L O

1989-05-01

Volatile solvents may evaporate during cone/plate viscometry so that false rheograms develop. This surface evaporation was prevented in a cod-liver oil-in-water emulsion stabilized with zanthoxylum gum by layering a film of cod-liver oil on the exposed surface of the emulsion test sample. The oil layer effectively prevented evaporation and did not alter significantly the rheological behaviour of the test material.

Trichromatic reconstruction from the interleaved cone mosaic: Bayesian model and the color appearance of small spots

PubMed Central

Brainard, David H.; Williams, David R.; Hofer, Heidi

2009-01-01

Observers use a wide range of color names, including white, to describe monochromatic flashes with a retinal size comparable to that of a single cone. We model such data as a consequence of information loss arising from trichromatic sampling. The model starts with the simulated responses of the individual L, M, and S cones actually present in the cone mosaic and uses these to reconstruct the L-, M-, and S-cone signals that were present at every image location. We incorporate the optics and the mosaic topography of individual observers, as well as the spatio-chromatic statistics of natural images. We simulated the experiment of H. Hofer, B. Singer, & D. R. Williams (2005) and predicted the color name on each simulated trial from the average chromaticity of the spot reconstructed by our model. Broad features of the data across observers emerged naturally as a consequence of the measured individual variation in the relative numbers of L, M, and S cones. The model’s output is also consistent with the appearance of larger spots and of sinusoidal contrast modulations. Finally, the model makes testable predictions for future experiments that study how color naming varies with the fine structure of the retinal mosaic. PMID:18842086

Calculation of stability derivatives for slowly oscillating bodies of revolution at Mach 1.0

NASA Technical Reports Server (NTRS)

Ruo, S. Y.; Liu, D. D.

1971-01-01

A parabolic method for steady transonic flow is extended to bodies of revolution oscillating in a sonic flow field. A Laplace transform technique is employed to derive the dipole solution, and the Adams-Sears iterative technique is used in the stability derivative calculation. A computer program is developed to perform the stability derivative calculation for the slowly oscillating cone and parabolic ogive. Inputs for the program are body geometry thickness ratio, acceleration constant, and pitch axis location. Sample calculations were performed for the parabolic ogive and circular cone and results are compared with those obtained by using other techniques and the available experimental data for circular cones.

The accumulation of genetic diversity within a canopy-stored seed bank.

PubMed

Ayre, David; O'Brien, Eleanor; Ottewell, Kym; Whelan, Rob

2010-07-01

Many plants regenerate after fire from a canopy-stored seed bank, in which seed are housed in fire resistant confructescences (cones) that remain on maternal plants. This strategy would be favoured if plants accumulate a sufficiently large and genetically diverse seed bank during interfire intervals. We use a 16-year demographic study and surveys of microsatellite variation to quantify and explain the rate of accumulation of genetic diversity within the canopy seed bank of the shrub Banksia spinulosa. Flowering and fruit set were highly variable. An initial sample in 1991 of 354 reproductively mature plants generated 426 cones over 16 years, of which only 55 cones from 40 maternal plants persisted until 2005. By genotyping seed from these 55 cones we demonstrated that genetic diversity accumulated rapidly within the seed bank. Resampling revealed that diversity was determined by the number, not the age, of cones. Cones were widely distributed among plants, outcrossing rates were high (mean t(m) = 1.00 +/- 0.04) and biparental inbreeding low. Adults displayed little evidence of isolation by distance and the genotypic diversity of seed cohorts was independent of the density of neighbouring potential sires. We therefore estimate that within at least 13 individual years the number of cones produced per year (14-63) would have contained 100% of the adult genetic diversity. We conclude that a highly outcrossed mating system and relatively widespread pollen dispersal ensure the rapid development of a genetically diverse and spatially and temporally homogeneous seed bank.

Impact of Offshore Wind Energy Plants on the Soil Mechanical Behaviour of Sandy Seafloors

NASA Astrophysics Data System (ADS)

Stark, Nina; Lambers-Huesmann, Maria; Zeiler, Manfred; Zoellner, Christian; Kopf, Achim

2010-05-01

Over the last decade, wind energy has become an important renewable energy source. Especially, the installation of offshore windfarms offers additional space and higher average wind speeds than the well-established windfarms onshore. Certainly, the construction of offshore wind turbines has an impact on the environment. In the framework of the Research at Alpha VEntus (RAVE) project in the German offshore wind energy farm Alpha Ventus (north of the island Borkum in water depths of about 30 m) a research plan to investigate the environmental impact had been put into place. An ongoing study focuses on the changes in soil mechanics of the seafloor close to the foundations and the development of scour. Here, we present results of the first geotechnical investigations after construction of the plants (ca. 1 - 6 months) compared to geotechnical measurements prior to construction. To study the soil mechanical behaviour of the sand, sediment samples from about thirty different positions were measured in the laboratory to deliver, e.g., grain size (0.063 - 0.3 mm), friction angles (~ 32°), unit weight (~ 19.9 kN/m³) and void ratios (~ 0.81). For acoustic visualisation, side-scan-sonar (towed and stationary) and multibeam-echosounders (hull mounted) were used. Data show a flat, homogenous seafloor prior to windmill erection, and scouring effects at and in the vicinity of the foundations afterwards. Geotechnical in-situ measurements were carried out using a standard dynamic Cone Penetration Testing lance covering the whole windfarm area excluding areas in a radius < 50 m from the installed windmills (due the accessibility with the required research vessel). In addition, the small free-fall penetrometer Nimrod was deployed at the same spots, and furthermore, in the areas close to the tripod foundations (down to a distance of ~ 5 m from the central pile). Before construction, CPT as well as Nimrod deployments confirm a flat, homogenous sandy area with tip resistance values ranging from 1200 - 1600 kPa (CPT with a mass of ~ 100 kg and an impact velocity of ~ 1 m/s) and quasi-static bearing capacities (qsbc.) mainly ranging from 39 - 69 kPa (Nimrod: mass of ~ 13 kg, impact velocity of ~ 8 m/s). There was no evidence for layering in results of both in-situ instruments. After construction, most of the positions show changes in sediment strength ranging from 10 % up to 100 % compared to the results prior to windmill construction. Extreme changes (> 50 %) occur above all close to the foundations. Furthermore, patterns of relatively soft zones (qsbc.: 50 - 80 kPa) and hard zones (qsbc. > 100 kPa) were mapped during the high-resolution surveys close to the foundation. Beside that, a very soft sediment layer (0.03 - 0.05 m) drapes most of the soft zones. This may be recently eroded and re-deposited sediment, whereas the hard zones may indicate areas of sediment erosion where looser material has been carried away. Reasons for sediment remobilization and changes in geotechnical properties may be scouring as a consequence of the changed hydrodynamics in the vicinity of the windmills. Besides first developments of scour, the side scan sonar results show relicts of the wind turbine erection (e.g., footprints of jack-up-platforms). First multibeam-echosounder measurements confirm sediment re-deposition due to scour in the lee of the main current direction and show traces of wind turbine erection equipment in the same areas where also the penetrometer measurements took place. In summary, a local impact of the wind turbines on the soil mechanical properties of the seafloor is attested from this initial post-erection survey. Future cruises (every 6 months) will complement those data, which will eventually allow us a comparison to, or even refinement of long-term scouring models.

Distribution of Mature Cones, Conelets, and Old Cones in Shortleaf Pine-Oak Stands an Uneven-Aged Regeneration Cut

Treesearch

Kenneth J. Grayson; Robert F. Wittwer; Michael G. Shelton

2004-01-01

Sixteen shortleaf pine trees were felled in a stand 10 years after an uneven-aged regeneration cut reduced pine basal area to 60 square feet per acre and hardwoods were controlled. Sixteen unreleased trees in an adjacent uncut pine-hardwood stand (120 square feet per acre) were felled for comparison. Sample trees were selected from four 2-inch d.b.h. classes (11, 13,...

The Effects of Diabetic Retinopathy and Pan-Retinal Photocoagulation on Photoreceptor Cell Function as Assessed by Dark Adaptometry

PubMed Central

Bavinger, J. Clay; Dunbar, Grace E.; Stem, Maxwell S.; Blachley, Taylor S.; Kwark, Leon; Farsiu, Sina; Jackson, Gregory R.; Gardner, Thomas W.

2016-01-01

Purpose The pathophysiology of vision loss in persons with diabetic retinopathy (DR) is complex and incompletely defined. We hypothesized that retinal pigment epithelium (RPE) and rod and cone photoreceptor dysfunction, as measured by dark adaptometry, would increase with severity of DR, and that pan-retinal photocoagulation (PRP) would exacerbate this dysfunction. Methods Dark adaptation (DA) was measured in subjects with diabetes mellitus and healthy controls. Dark adaptation was measured at 5° superior to the fovea following a flash bleach, and the data were analyzed to yield cone and rod sensitivity curves. Retinal layer thicknesses were quantified using spectral-domain optical coherence tomography (OCT). Results The sample consisted of 23 controls and 73 diabetic subjects. Subjects with moderate nonproliferative diabetic retinopathy (NPDR) exhibited significant impairment of rod recovery rate compared with control subjects (P = 0.04). Cone sensitivity was impaired in subjects with proliferative diabetic retinopathy (PDR) (type 1 diabetes mellitus [T1DM]: P = 0.0047; type 2 diabetes mellitus [T2DM]: P < 0.001). Subjects with untreated PDR compared with subjects treated with PRP exhibited similar rod recovery rates and cone sensitivities. Thinner RPE as assessed by OCT was associated with slower rod recovery and lower cone sensitivity, and thinner photoreceptor inner segment/outer segment layer was associated with lower cone sensitivity. Conclusions The results suggest that RPE and photoreceptor cell dysfunction, as assessed by cone sensitivity level and rod- and RPE-mediated dark adaptation, progresses with worsening DR, and rod recovery dysfunction occurs earlier than cone dysfunction. Function was preserved following PRP. The findings suggest multiple defects in retinoid function and provide potential points to improve visual function in persons with PDR. PMID:26803796

Four studies on effects of environmental factors on the quality of National Atmospheric Deposition Program measurements

USGS Publications Warehouse

Wetherbee, Gregory A.; Latysh, Natalie E.; Lehmann, Christopher M.B.; Rhodes, Mark F.

2011-01-01

Selected aspects of National Atmospheric Deposition Program / National Trends Network (NADP/NTN) protocols are evaluated in four studies. Meteorological conditions have minor impacts on the error in NADP/NTN sampling. Efficiency of frozen precipitation sample collection is lower than for liquid precipitation samples. Variability of NTN measurements is higher for relatively low-intensity deposition of frozen precipitation than for higher-intensity deposition of liquid precipitation. Urbanization of the landscape surrounding NADP/NTN sites is not affecting trends in wet-deposition chemistry data to a measureable degree. Five NADP siting criteria intended to preserve wet-deposition sample integrity have varying degrees of effectiveness. NADP siting criteria for objects within the 90 degrees cones and trees within the 120 degrees cones projected from the collector bucket to sky are important for protecting sample integrity. Tall vegetation, fences, and other objects located within 5 meters of the collectors are related to the frequency of visible sample contamination, indicating the importance of these factors in NADP siting criteria.

Accurate T1 mapping of short T2 tissues using a three-dimensional ultrashort echo time cones actual flip angle imaging-variable repetition time (3D UTE-Cones AFI-VTR) method.

PubMed

Ma, Ya-Jun; Lu, Xing; Carl, Michael; Zhu, Yanchun; Szeverenyi, Nikolaus M; Bydder, Graeme M; Chang, Eric Y; Du, Jiang

2018-08-01

To develop an accurate T 1 measurement method for short T 2 tissues using a combination of a 3-dimensional ultrashort echo time cones actual flip angle imaging technique and a variable repetition time technique (3D UTE-Cones AFI-VTR) on a clinical 3T scanner. First, the longitudinal magnetization mapping function of the excitation pulse was obtained with the 3D UTE-Cones AFI method, which provided information about excitation efficiency and B 1 inhomogeneity. Then, the derived mapping function was substituted into the VTR fitting to generate accurate T 1 maps. Numerical simulation and phantom studies were carried out to compare the AFI-VTR method with a B 1 -uncorrected VTR method, a B 1 -uncorrected variable flip angle (VFA) method, and a B 1 -corrected VFA method. Finally, the 3D UTE-Cones AFI-VTR method was applied to bovine bone samples (N = 6) and healthy volunteers (N = 3) to quantify the T 1 of cortical bone. Numerical simulation and phantom studies showed that the 3D UTE-Cones AFI-VTR technique provides more accurate measurement of the T 1 of short T 2 tissues than the B 1 -uncorrected VTR and VFA methods or the B 1 -corrected VFA method. The proposed 3D UTE-Cones AFI-VTR method showed a mean T 1 of 240 ± 25 ms for bovine cortical bone and 218 ± 10 ms for the tibial midshaft of human volunteers, respectively, at 3 T. The 3D UTE-Cones AFI-VTR method can provide accurate T 1 measurements of short T 2 tissues such as cortical bone. Magn Reson Med 80:598-608, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2018 International Society for Magnetic Resonance in Medicine.

Elastomeric Microchip Electrospray Emitter for Stable Cone-Jet Mode Operation in the Nano-Flow Regime

PubMed Central

Kelly, Ryan T.; Tang, Keqi; Irimia, Daniel; Toner, Mehmet; Smith, Richard D.

2009-01-01

Despite widespread interest in combining lab-on-a-chip technologies with mass spectrometry (MS)-based analyses, the coupling of microfluidics to electrospray ionization (ESI)-MS remains challenging. We report a robust, integrated poly(dimethylsiloxane) microchip interface for ESI-MS using simple and widely accessible microfabrication procedures. The interface uses an auxiliary channel to provide electrical contact for the stable cone-jet electrospray without sample loss or dilution. The electric field at the channel terminus is enhanced by two vertical cuts that cause the interface to taper to a line rather than to a point, and the formation of a small Taylor cone at the channel exit ensures sub-nL post-column dead volumes. Cone-jet mode electrospray was demonstrated for up to 90% aqueous solutions and for extended durations. Comparable ESI-MS sensitivities were achieved using both microchip and conventional fused silica capillary emitters, but stable cone-jet mode electrosprays could be established over a far broader range of flow rates (from 50-1000 nL/min) and applied potentials using the microchip emitters. This attribute of the microchip emitter should simplify electrospray optimization and make the stable electrospray more resistant to external perturbations. PMID:18419138

Coal-shale interface detection

NASA Technical Reports Server (NTRS)

Broussard, P. H.; Burch, J. L.; Drost, E. J.; Stein, R. J. (Inventor)

1979-01-01

A penetrometer for coal-shale interface detection is presented. It is used with coal cutting equipment consisting of a reciprocating hammer, having an accelerometer mounted thereon to measure the impact of the hammer as it penetrates the ceiling or floor surface of a mine. Additionally, a pair of reflectometers simultaneously view the same surface, and the outputs from the accelerometer and reflectometers are detected and jointly registered to determine when an interface between coal and shale is being cut through.

Color, contrast sensitivity, and the cone mosaic.

PubMed Central

Williams, D; Sekiguchi, N; Brainard, D

1993-01-01

This paper evaluates the role of various stages in the human visual system in the detection of spatial patterns. Contrast sensitivity measurements were made for interference fringe stimuli in three directions in color space with a psychophysical technique that avoided blurring by the eye's optics including chromatic aberration. These measurements were compared with the performance of an ideal observer that incorporated optical factors, such as photon catch in the cone mosaic, that influence the detection of interference fringes. The comparison of human and ideal observer performance showed that neural factors influence the shape as well as the height of the foveal contrast sensitivity function for all color directions, including those that involve luminance modulation. Furthermore, when optical factors are taken into account, the neural visual system has the same contrast sensitivity for isoluminant stimuli seen by the middle-wavelength-sensitive (M) and long-wavelength-sensitive (L) cones and isoluminant stimuli seen by the short-wavelength-sensitive (S) cones. Though the cone submosaics that feed these chromatic mechanisms have very different spatial properties, the later neural stages apparently have similar spatial properties. Finally, we review the evidence that cone sampling can produce aliasing distortion for gratings with spatial frequencies exceeding the resolution limit. Aliasing can be observed with gratings modulated in any of the three directions in color space we used. We discuss mechanisms that prevent aliasing in most ordinary viewing conditions. Images Fig. 1 Fig. 8 PMID:8234313

Multiple dendrochronological responses to the eruption of Cinder Cone, Lassen Volcanic National Park, California

USGS Publications Warehouse

Sheppard, P.R.; Ort, M.H.; Anderson, K.C.; Clynne, M.A.; May, E.M.

2009-01-01

Two dendrochronological properties – ring width and ring chemistry – were investigated in trees near Cinder Cone in Lassen Volcanic National Park, northeastern California, for the purpose of re-evaluating the date of its eruption. Cinder Cone is thought to have erupted in AD 1666 based on ring-width evidence, but interpreting ring-width changes alone is not straightforward because many forest disturbances can cause changes in ring width. Old Jeffrey pines growing in Cinder Cone tephra and elsewhere for control comparison were sampled. Trees growing in tephra show synchronous ring-width changes at AD 1666, but this ring-width signal could be considered ambiguous for dating the eruption because changes in ring width can be caused by other events. Trees growing in tephra also show changes in ring phosphorus, sulfur, and sodium during the late 1660s, but inter-tree variability in dendrochemical signals makes dating the eruption from ring chemistry alone difficult. The combination of dendrochemistry and ring-width signals improves confidence in dating the eruption of Cinder Cone over the analysis of just one ring-growth property. These results are similar to another case study using dendrochronology of ring width and ring chemistry at Parícutin, Michoacán, Mexico, a cinder cone that erupted beginning in 1943. In both cases, combining analysis with ring width and ring chemistry improved confidence in the dendro-dating of the eruptions.

Relationships between Xanthohumol and Polyphenol Content in Hop Leaves and Hop Cones with Regard to Water Supply and Cultivar

PubMed Central

Čeh, Barbara; Kač, Milica; Košir, Iztok J.; Abram, Veronika

2007-01-01

The effect of water supply – especially of drought stress – on the content of some secondary metabolites in hops (Humulus lupulus L.) was studied. The experiment took place in 2006. Some relevant data from 2005 were included for comparison. Leaves and cones of nine hop cultivars grown under field conditions as well as in a pot experiment under three water regimes were analyzed. The cultivars ranged from those most grown in Slovenia to promising crossbreed being tested. Leaves were sampled from July 18, 2006 to August 18, 2006, while cones were picked in the time of technological maturity. Standard analytical methods were applied to determine the contents of xanthohumol, polyphenols and α-acids in hop leaves and hop cones. The contents of the secondary metabolites in question depended more on the cultivar under investigation than on the water supply, at least as far the growing conditions for a relatively normal development of the plant were met.

Synergistic effect of nisin and cone essential oil of Metasequoia glyptostroboides Miki ex Hu against Listeria monocytogenes in milk samples.

PubMed

Yoon, Jung In; Bajpai, Vivek K; Kang, Sun Chul

2011-01-01

This study was undertaken to evaluate the effect of nisin and cone essential oil of Metasequoia glyptostroboides against Listeria monocytogenes ATCC 19116 inoculated in whole (8%), low (1%) and skim (no fat content) milks. Essential oil at the concentrations of 2% and 5% revealed strong antilisterial effect against L. monocytogenes ATCC 19116 in all categories of milks. Nisin at the concentrations of 250 and 500 IU/ml displayed a remarkable antilisterial effect as compared to the control group. Also, the synergistic combinations of cone essential oil (1% and 2%) and nisin (62.5, 125, 250 and 500 IU/ml) had a remarkable antilisterial activity in all categories of whole, low and skim milks after 14 days. Results of this study indicate that the cone essential oil of M. glyptostroboides might be a useful candidate for using in food industry to control the growth of pathogenic microorganisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds.

PubMed

Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedl, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

2016-07-12

Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination.

A new Permian gnetalean cone as fossil evidence for supporting current molecular phylogeny.

PubMed

Wang, Zi-Qiang

2004-08-01

The order Gnetales has been the central focus of controversy in seed plant phylogeny. Traditional treatment of morphology supports the anthophyte hypothesis with Gnetales sister to angiosperms but current molecular data reject this hypothesis. A new fossil gnetalean cone, Palaeognetaleana auspicia gen. et sp. nov., is reported from the Upper Permian in North China, and its phylogenic implications are considered. Samples of cones from the upper part of the Upper Permian redbeds of Baode section, northwestern Shanxi Province, China, were examined. The cone is characterized by its unusual nature of reproduction that combines features of post-Triassic gnetaleans and some of the Palaeozoic conifers. It is made up of a number of imbricate axillary units, each simply formed by an ovule and a subtending bract, which may be comparable with the axillary seed-scale complex of some of the Palaeozoic conifer cones. The cone exhibits at least a partially bisexual character that appears to have pollen sacs with monosulcate ribbed pollen grains and sessile, asymmetric, and radiospermic ovules. The ovule has an integument of three envelopes: an outer one of pointed scales; a middle sclerified one; and an inner cuticle that extends upward into a micropyle with an oblique tip. The new Permian cone has unequivocal affinity with the Gnetales. The fossil has considerably extended the divergence time of the Gnetales from 140 (210?) back to 270 myr ago and, therefore, provides the first significant fossil evidence to support the current conclusion based on molecular data of seed plants, i.e. monophyletic gymnosperms, comprising the Gnetales are closely related to conifers.

Hydrogeology and ground-water quality of Valley Forge National Historical Park, Montgomery County, Pennsylvania

USGS Publications Warehouse

Sloto, Ronald A.; McManus, B. Craig

1996-01-01

Valley Forge National Historical Park is just southwest of the Commodore Semiconductor Group (CSG) National Priorities List (Superfund) Site, a source of volatile organic compounds (VOC's) in ground water. The 7.5-square-mile study area includes the part of the park in Lower Providence and West Norriton Townships in Montgomery County, Pa., and surrounding vicinity. The park is underlain by sedimentary rocks of the Upper Triassic age stockton Formation. A potentiometric-surface map constructed from water levels measured in 59 wells shows a cone of depression, approximately 0.5 mile in diameter, centered near the CSG Site. The cone of depression is caused by the pumping of six public supply wells. A ground-water divide between the cone of depression and Valley Forge National Historical Park provides a hydraulic barrier to the flow of ground water and contaminants from the CSG Site to the park. If pumping in the cone of depression was to cease, water levels would recover, and the ground-water divide would shift to the north. A hydraulic gradient between the CSG Site and the Schuylkill River would be established, causing contaminated ground water to flow to the park.Water samples were collected from 12 wells within the park boundary and 9 wells between the park boundary and the ground-water divide to the north of the park. All water samples were analyzed for physical properties (field determinations), nutrients, common ions, metals and other trace constituents, and VOC's. Water samples from the 12 wells inside the park boundary also were analyzed for pesticides. Concentrations of inorganic constituents in the water samples did not exceed U.S. Environmental Protection Agency maximum contaminant levels. Very low concentrations of organic compounds were detected in some of the water samples. VOC's were detected in water from 76 percent of the wells sampled; the maximum concentration detected was 5.8 micrograms per liter of chloroform. The most commonly detected VOC was chloroform. The second most commonly detected compound was methyl tert-butyl ether (MTBE), which was detected in water from 24 percent of wells sampled. Several pesticides were detected in water samples collected from within the park boundaries.: chlordane, DDD, dieldrin, endrin, heptachlor epoxide, and simazine. Concentrations of the detected pesticides were 0.1 micrograms per liter or less and did not exceed U.S. Environmental Protection Agency maximum contaminant levels.

An Accurate Scatter Measurement and Correction Technique for Cone Beam Breast CT Imaging Using Scanning Sampled Measurement (SSM) Technique.

PubMed

Liu, Xinming; Shaw, Chris C; Wang, Tianpeng; Chen, Lingyun; Altunbas, Mustafa C; Kappadath, S Cheenu

2006-02-28

We developed and investigated a scanning sampled measurement (SSM) technique for scatter measurement and correction in cone beam breast CT imaging. A cylindrical polypropylene phantom (water equivalent) was mounted on a rotating table in a stationary gantry experimental cone beam breast CT imaging system. A 2-D array of lead beads, with the beads set apart about ~1 cm from each other and slightly tilted vertically, was placed between the object and x-ray source. A series of projection images were acquired as the phantom is rotated 1 degree per projection view and the lead beads array shifted vertically from one projection view to the next. A series of lead bars were also placed at the phantom edge to produce better scatter estimation across the phantom edges. Image signals in the lead beads/bars shadow were used to obtain sampled scatter measurements which were then interpolated to form an estimated scatter distribution across the projection images. The image data behind the lead bead/bar shadows were restored by interpolating image data from two adjacent projection views to form beam-block free projection images. The estimated scatter distribution was then subtracted from the corresponding restored projection image to obtain the scatter removed projection images.Our preliminary experiment has demonstrated that it is feasible to implement SSM technique for scatter estimation and correction for cone beam breast CT imaging. Scatter correction was successfully performed on all projection images using scatter distribution interpolated from SSM and restored projection image data. The resultant scatter corrected projection image data resulted in elevated CT number and largely reduced the cupping effects.

Membrane-Soil Composite Layers in the Design, Construction, and Performance of an Expedient Bridge and Approach.

DTIC Science & Technology

1982-09-01

Engineering News-Record 1977). The concept is that of a composite soil-membrane system with tensile and flexural strengths greater than soil alone can...uniformity 2 Mean diameter 0.5 mm Sandbags 31. Sandbags used in this project were 14 x 26 in. in size and were made of jute or kenaf burlap...support 4. Converted airfield index penetrometer readings for the upper 6 in. of foundation soil indicated similar relative strengths at the base of

Lunar surface engineering properties experiment definition

NASA Technical Reports Server (NTRS)

Mitchell, J. K.; Goodman, R. E.; Hurlbut, F. C.; Houston, W. N.; Willis, D. R.; Witherspoon, P. A.; Hovland, H. J.

1971-01-01

Research on the mechanics of lunar soils and on developing probes to determine the properties of lunar surface materials is summarized. The areas of investigation include the following: soil simulation, soil property determination using an impact penetrometer, soil stabilization using urethane foam or phenolic resin, effects of rolling boulders down lunar slopes, design of borehole jack and its use in determining failure mechanisms and properties of rocks, and development of a permeability probe for measuring fluid flow through porous lunar surface materials.

Implementation of DOP Replacement with Selected Materials in Mask and Filter Testing Penetrometer Machines.

DTIC Science & Technology

1992-06-01

gene mutation procedures normally is done involving microbes or mammalian cells- most frequently it is the Ames assay which we have already completed...success- fully for the compound Emery 3004. Tier 2 assays for gene mutation utilize in vivo and host mediated tests which usually are considered in...compounds for more complex costly test procedures can be accomplished in this tier, but results should not be used to estimate risk to mammalian systems. Gene

Site Characterization and Analysis Penetrometer System (SCAPS) Heavy Metal Sensors

DTIC Science & Technology

2003-04-01

gigawatts per square centimeter (GW/cm2). Within the small volume about the focal point, rapid heating, vaporization, and ionization of a small amount of the...2001). Briefly, the light emitted from the fiber in the probe is collimated, turned by a quartz prism, and focused by a short- focal -length quartz 5...are decoupled using the configuration shown in Figure 1. The excitation beam is focused by a 25-cm focal length lens through a 2-inch aluminum mirror

A comparative study of modern and fossil cone scales and seeds of conifers: A geochemical approach

USGS Publications Warehouse

Artur, Stankiewicz B.; Mastalerz, Maria; Kruge, M.A.; Van Bergen, P. F.; Sadowska, A.

1997-01-01

Modern cone scales and seeds of Pinus strobus and Sequoia sempervirens, and their fossil (Upper Miocene, c. 6 Mar) counterparts Pinus leitzii and Sequoia langsdorfi have been studied using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), electron-microprobe and scanning electron microscopy. Microscopic observations revealed only minor microbial activity and high-quality structural preservation of the fossil material. The pyrolysates of both modern genera showed the presence of ligno-cellulose characteristic of conifers. However, the abundance of (alkylated)phenols and 1,2-benzenediols in modern S. sempervirens suggests the presence of non-hydrolysable tannins or abundant polyphenolic moieties not previously reported in modern conifers. The marked differences between the pyrolysis products of both modern genera are suggested to be of chemosystematic significance. The fossil samples also contained ligno-cellulose which exhibited only partial degradation, primarily of the carbohydrate constituents. Comparison between the fossil cone scale and seed pyrolysates indicated that the ligno-cellulose complex present in the seeds is chemically more resistant than that in the cone scales. Principal component analysis (PCA) of the pyrolysis data allowed for the determination of the discriminant functions used to assess the extent of degradation and the chemosystematic differences between both genera and between cone scales and seeds. Elemental composition (C, O, S), obtained using electron-microprobe, corroborated the pyrolysis results. Overall, the combination of chemical, microscopic and statistical methods allowed for a detailed characterization and chemosystematic interpretations of modern and fossil conifer cone scales and seeds.

Comparison of the Atomic Oxygen Erosion Depth and Cone Height of Various Materials at Hyperthermal Energy

NASA Technical Reports Server (NTRS)

Waters, Deborah L.; Banks, Bruce A.; Thorson, Stephen D.; deGroh, Kim, K.; Miller, Sharon K.

2007-01-01

Atomic oxygen readily reacts with most spacecraft polymer materials exposed to the low Earth orbital (LEO) environment. If the atomic oxygen arrival comes from a fixed angle of impact, the resulting erosion will foster the development of a change in surface morphology as material thickness decreases. Hydrocarbon and halopolymer materials, as well as graphite, are easily oxidized and textured by directed atomic oxygen in LEO at energies of approx.4.5 eV. What has been curious is that the ratio of cone height to erosion depth is quite different for different materials. The formation of cones under fixed direction atomic oxygen attack may contribute to a reduction in material tensile strength in excess of that which would occur if the cone height to erosion depth ratio was very low because of greater opportunities for crack initiation. In an effort to understand how material composition affects the ratio of cone height to erosion depth, an experimental investigation was conducted on 18 different materials exposed to a hyperthermal energy directed atomic oxygen source (approx.70 eV). The materials were first salt-sprayed to provide microscopic local areas that would be protected from atomic oxygen. This allowed erosion depth measurements to be made by scanning microscopy inspection. The polymers were then exposed to atomic oxygen produced by an end Hall ion source that was operated on pure oxygen. Samples were exposed to an atomic oxygen effective fluence of 1.0x10(exp 20) atoms/sq cm based on Kapton H polyimide erosion. The average erosion depth and average cone height were determined using field emission scanning electron microscopy (FESEM). The experimental ratio of average cone height to erosion depth is compared to polymer composition and other properties.

Feasibility of using an inversion-recovery ultrashort echo time (UTE) sequence for quantification of glenoid bone loss.

PubMed

Ma, Ya-Jun; West, Justin; Nazaran, Amin; Cheng, Xin; Hoenecke, Heinz; Du, Jiang; Chang, Eric Y

2018-02-02

To utilize the 3D inversion recovery prepared ultrashort echo time with cones readout (IR-UTE-Cones) MRI technique for direct imaging of lamellar bone with comparison to the gold standard of computed tomography (CT). CT and MRI was performed on 11 shoulder specimens and three patients. Five specimens had imaging performed before and after glenoid fracture (osteotomy). 2D and 3D volume-rendered CT images were reconstructed and conventional T1-weighted and 3D IR-UTE-Cones MRI techniques were performed. Glenoid widths and defects were independently measured by two readers using the circle method. Measurements were compared with those made from 3D CT datasets. Paired-sample Student's t tests and intraclass correlation coefficients were performed. In addition, 2D CT and 3D IR-UTE-Cones MRI datasets were linearly registered, digitally overlaid, and compared in consensus by these two readers. Compared with the reference standard (3D CT), glenoid bone diameter measurements made on 2D CT and 3D IR-UTE-Cones were not significantly different for either reader, whereas T1-weighted images underestimated the diameter (mean difference of 0.18 cm, p = 0.003 and 0.16 cm, p = 0.022 for readers 1 and 2, respectively). However, mean margin of error for measuring glenoid bone loss was small for all modalities (range, 1.46-3.92%). All measured ICCs were near perfect. Digitally registered 2D CT and 3D IR-UTE-Cones MRI datasets yielded essentially perfect congruity between the two modalities. The 3D IR-UTE-Cones MRI technique selectively visualizes lamellar bone, produces similar contrast to 2D CT imaging, and compares favorably to measurements made using 2D and 3D CT.

How Old is Cone Crater at the Apollo 14 Landing Site?

NASA Astrophysics Data System (ADS)

Hiesinger, Harald; Simon, Ina; van der Bogert, Carolyn H.; Robinson, Mark S.; Plescia, Jeff B.

2015-04-01

The Lunar Reconnaissance Orbiter (LRO) Narrow Angle Cameras (NAC) provides new opportunities to investigate crater size-frequency distributions (CSFDs) on individual geological units at key lunar impact craters. We performed new CSFD measurements for the Copernican-aged Cone crater at the Apollo 14 landing site because it is an anchor point for the lunar cratering chronology at young ages [1-4]. Cone crater (340 m diameter) is located about 1100 m NE of the Apollo 14 landing site on a 90 m high ridge of the Fra Mauro Formation, and exhibits a sharp rim [e.g., 5,6,7]. Samples from Cone crater were collected from four stations (Dg, C1, C2, C') during the Apollo 14 mission [7]. Exposure ages of those samples were used to date the formation of Cone crater. Although there is a considerable range of exposure ages (~12 Ma [8] to ~661 Ma [9]), several studies of Cone crater samples indicate an age of ~25-26 Ma [e.g., 2,10,11]. On the basis of our CSFD measurements we determined an absolute model age (AMA) for Cone crater of ~39 Ma, which is in the range of model ages derived by previous CSFD measurements that vary between ~24 Ma [12] and ~73 Ma [13]. However, we found a wide spread of model ages ranging from ~16 to ~82 Ma for individual areas on the crater ejecta blanket. Like [13], we find that the CSFD measurements on LROC images yield older AMAs than previous CSFDs [e.g., 12]. However, our results are closer to the older CSFDs than to those of [13] and are just within the error bars of [14]. Our derived N(1) = 3.26 x 10-5 km-2 is almost identical to the N(1) = 3.36 x 10-5 km-2 of [15]. Comparing the CSFD results to exposure ages of the returned samples we find somewhat older ages. However, at least two of our count areas produce AMAs that are within the error bars of the exposure ages [e.g., 10]. Six other areas show ages that are within two standard deviations to the exposure ages [e.g., 10]. For two count areas that were directly sampled, we obtained ages that are 10 and 23 Ma older than the exposure ages [e.g., 10]. We find that CSFD measurements performed on the ejecta blanket of Cone crater yield AMAs that agree well with the exposure ages, considering the relatively small count areas and the hummocky nature of the ejecta blanket. However, the AMAs are generally older than the exposure ages, which may be due to the small count area sizes [16], a possibly higher recent impact rate [17], some unidentified secondary craters [13], poor calibration of the production function, or inaccurate exposure ages. [1] Hiesinger et al. (2012) J. Geophys. Res. 117. [2] Stöffler and Ryder (2001) Chronology and Evolution of Mars. [3] Neukum (1983) Habil. thesis, U. of Munich. [4] Neukum et al. (2001) Space Sci. Rev. 96. [5] Swann et al. (1971) Apollo 14 Prelim. Sci. Rep. [6] Carlson (1978) NASA STI/Recon Technical Report. [7] Swann (1977) Washington US Govt. Print. Off. [8] Bhandari et al. (1972) Proc. Lunar Planet. Sci. Conf. 3. [9] Crozaz et al. (1972) Proc. Lunar Planet. Sci. Conf. 3. [10] Arvidson et al. (1975) Moon 13. [11] Stadermann et al. (1991) Geochim. Cosmochim. Acta 55. [12] Moore et al. (1980) Moon and Planets 23. [13] Plescia and Robinson (2011) LPSC 42. [14] Williams et al. (2014) Icarus 235. [15] Robbins (2014) Earth Planet. Sci. Lett. 403. [16] van der Bogert et al. (2015) LPSC 46. [17] McEwen et al. (2015) LPSC 46.

Multiple rod-cone and cone-rod photoreceptor transmutations in snakes: evidence from visual opsin gene expression.

PubMed

Simões, Bruno F; Sampaio, Filipa L; Loew, Ellis R; Sanders, Kate L; Fisher, Robert N; Hart, Nathan S; Hunt, David M; Partridge, Julian C; Gower, David J

2016-01-27

In 1934, Gordon Walls forwarded his radical theory of retinal photoreceptor 'transmutation'. This proposed that rods and cones used for scotopic and photopic vision, respectively, were not fixed but could evolve into each other via a series of morphologically distinguishable intermediates. Walls' prime evidence came from series of diurnal and nocturnal geckos and snakes that appeared to have pure-cone or pure-rod retinas (in forms that Walls believed evolved from ancestors with the reverse complement) or which possessed intermediate photoreceptor cells. Walls was limited in testing his theory because the precise identity of visual pigments present in photoreceptors was then unknown. Subsequent molecular research has hitherto neglected this topic but presents new opportunities. We identify three visual opsin genes, rh1, sws1 and lws, in retinal mRNA of an ecologically and taxonomically diverse sample of snakes central to Walls' theory. We conclude that photoreceptors with superficially rod- or cone-like morphology are not limited to containing scotopic or photopic opsins, respectively. Walls' theory is essentially correct, and more research is needed to identify the patterns, processes and functional implications of transmutation. Future research will help to clarify the fundamental properties and physiology of photoreceptors adapted to function in different light levels. © 2016 The Author(s).

Five million years of compositionally diverse, episodic volcanism: Construction of Davidson Seamount atop an abandoned spreading center

NASA Astrophysics Data System (ADS)

Clague, D. A.; Paduan, J. B.; Duncan, R. A.; Huard, J. J.; Davis, A. S.; Castillo, P. R.; Lonsdale, P.; Devogelaere, A.

2009-12-01

Davidson Seamount, a volcano located about 80 km off the central California coast, has a volume of ˜320 km3 and consists of a series of parallel ridges serrated with steep cones. Davidson was sampled and its morphology observed during 27 ROV Tiburon dives. During those dives, 286 samples of lava, volcaniclastite, and erratics from the continental margin were collected, with additional samples from one ROV-collected push core and four gravity cores. We report glass compositions for 99 samples and 40Ar-39Ar incremental heating age data for 20 of the samples. The glass analyses are of hawaiite (62%), mugearite (13%), alkalic basalt (9%), and tephrite (8%), with minor transitional basalt (2%), benmoreite (2%), and trachyandesite (2%). The lithologies are irregularly distributed in space and time. The volcano erupted onto crust inferred to be 20 Ma from seafloor magnetic anomalies. Ages of the lavas range from 9.8 to 14.8 Ma. The oldest rocks are from the central ridge, and the youngest are from the flanks and southern end of the edifice. The compositions of the 18 reliably dated volcanic cones vary with age such that the oldest lavas are the most fractionated. The melts lost 65% to nearly 95% of their initial S because of bubble loss during vesiculation, and the shallowest samples have S contents similar to lava erupted subaerially in Hawaii. Despite this similarity in S contents, there is scant other evidence to suggest that Davidson was ever an island. The numerous small cones of disparate chemistry and the long eruptive period suggest episodic growth of the volcano over at least 5 Myr and perhaps as long as 10 Myr if it began to grow when the spreading ridge was abandoned.

Measurement of in-situ strength using projectile penetration: Tests of a new launching system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hearst, J.R.; Newmark, R.L.; Charest, J.A.

1987-10-01

The Lawrence Livermore National Laboratory has a continuing need to measure rock strength in situ, both for simple prediction of cavity size, and as input to computational models. In a previous report we compared two methods for measuring formation strength in situ: projectile penetration and a cone penetrometer. We determined that the projectile method was more promising for application to our large-diameter (2-4-m) hole environment. A major practical problem has been the development of a launcher and an apparatus for measuring depth of penetration that would be suitable for use in large-diameter holes. We are developing a gas-gun launcher systemmore » that will be capable of measuring both depth of penetration and deceleration of a reusable projectile. The current version of the launcher is trailer-mounted for testing at our Nevada Test Site (NTS) in tunnels and outcrops, but its design is such that it can be readily adapted for emplacement hole use. We test the current launcher on 60-cm cubes of gypsum cement, mixed to provie a range of densities (1.64 to 2.0 g/cc) and strengths (3 to 17 MPa). We compared depth of penetration of a 84-g projectile from a ''Betsy'' seismic gun - traveling on the order of 500 m/s - with the depth of penetration of a 13-kg projectile from the gas gun - traveling on the order of 30 m/s. For projectiles with the same nose size and shape, impacting targets of approximately constant strength, penetration depth was proportional to projectile kinetic energy. The ratio of kinetic energy to penetration depth was approximately proportional to target strength. Tests in tuffs with a wide range of strengths at NTS gave a similar linear relationship between the ratio of kinetic energy to penetration and target strength, and also a linear relationship between deceleration and strength. It appears that penetration can indeed be used as a semiquantitative measure of strength.« less

Geophysical investigation, Salmon Site, Lamar County, Mississippi

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Geophysical surveys were conducted in 1992 and 1993 on 21 sites at the Salmon Site (SS) located in Lamar County, Mississippi. The studies are part of the Remedial Investigation/Feasibility Study (RI/FS) being conducted by IT Corporation for the U.S. Department of Energy (DOE). During the 1960s, two nuclear devices and two chemical tests were detonated 826 meters (in) (2710 feet [ft]) below the ground surface in the salt dome underlying the SS. These tests were part of the Vela Uniform Program conducted to improve the United States capability to detect, identify, and locate underground nuclear detonations. The RI/FS is beingmore » conducted to determine if any contamination is migrating from the underground shot cavity in the salt dome and if there is any residual contamination in the near surface mud and debris disposal pits used during the testing activities. The objective of the surface geophysical surveys was to locate buried debris, disposal pits, and abandoned mud pits that may be present at the site. This information will then be used to identify the locations for test pits, cone penetrometer tests, and drill hole/monitor well installation. The disposal pits were used during the operation of the test site in the 1960s. Vertical magnetic gradient (magnetic gradient), electromagnetic (EM) conductivity, and ground-penetrating radar (GPR) surveys were used to accomplish these objectives. A description of the equipment used and a theoretical discussion of the geophysical methods are presented Appendix A. Because of the large number of figures relative to the number of pages of text, the geophysical grid-location maps, the contour maps of the magnetic-gradient data, the contour maps of the EM conductivity data, and the GPR traverse location maps are located in Appendix B, Tabs I through 22. In addition, selected GPR records are located in Appendix C.« less

Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds

PubMed Central

Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedl, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

2016-01-01

Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination. DOI: http://dx.doi.org/10.7554/eLife.15675.001 PMID:27402384

Monitoring early phases of orthodontic treatment by means of Raman spectroscopies

NASA Astrophysics Data System (ADS)

d'Apuzzo, Fabrizia; Perillo, Letizia; Delfino, Ines; Portaccio, Marianna; Lepore, Maria; Camerlingo, Carlo

2017-11-01

Gingival crevicular fluid (GCF) is a site-specific exudate in the gingival sulcus. GCF composition changes in response to diseases or mechanical stimuli, such as those occurring during orthodontic treatments. Raman microspectroscopy (μ-RS) and surface-enhanced Raman spectroscopy (SERS) were adopted for a GCF analysis during different initial phases of orthodontic force application. GCF samples were pooled from informed patients using paper cones. SERS spectra were obtained from GCF extracted from these cones, whereas μ-RS spectra were directly acquired on paper cones without any manipulation. The spectral characteristics of the main functional groups and the changes in cytochrome, amide III, and amide I contributions were highlighted in the different phases of orthodontic treatment with both SERS and μ-RS analysis. μ-RS directly performed on the paper cones together with proper statistical methods can offer an effective approach for the development of a tool for monitoring the processes occurring during orthodontic treatments, which may help the clinician in the choice of type of treatment individually for each patient and accelerate and improve the orthodontic therapy.

Bilateral Symmetry of Visual Function Loss in Cone-Rod Dystrophies.

PubMed

Galli-Resta, Lucia; Falsini, Benedetto; Rossi, Giuseppe; Piccardi, Marco; Ziccardi, Lucia; Fadda, Antonello; Minnella, Angelo; Marangoni, Dario; Placidi, Giorgio; Campagna, Francesca; Abed, Edoardo; Bertelli, Matteo; Zuntini, Monia; Resta, Giovanni

2016-07-01

To investigate bilateral symmetry of visual impairment in cone-rod dystrophy (CRD) patients and understand the feasibility of clinical trial designs treating one eye and using the untreated eye as an internal control. This was a retrospective study of visual function loss measures in 436 CRD patients followed at the Ophthalmology Department of the Catholic University in Rome. Clinical measures considered were best-corrected visual acuity, focal macular cone electroretinogram (fERG), and Ganzfeld cone-mediated and rod-mediated electroretinograms. Interocular agreement in each of these clinical indexes was assessed by t- and Wilcoxon tests for paired samples, structural (Deming) regression analysis, and intraclass correlation. Baseline and follow-up measures were analyzed. A separate analysis was performed on the subset of 61 CRD patients carrying likely disease-causing mutations in the ABCA4 gene. Statistical tests show a very high degree of bilateral symmetry in the extent and progression of visual impairment in the fellow eyes of CRD patients. These data contribute to a better understanding of CRDs and support the feasibility of clinical trial designs involving unilateral eye treatment with the use of fellow eye as internal control.

DISCRIMINATION OF ALTERED BASALTIC ROCKS IN THE SOUTHWESTERN UNITED STATES BY ANALYSIS OF LANDSAT THEMATIC MAPPER DATA.

USGS Publications Warehouse

Davis, Philip A.; Berlin, Graydon L.; Chavez, Pat S.

1987-01-01

Landsat Thematic Mapper image data were analyzed to determine their ability to discriminate red cone basalts from gray flow basalts and sedimentary country rocks for three volcanic fields in the southwestern United States. Analyses of all of the possible three-band combinations of the six nonthermal bands indicate that the combination of bands 1, 4, and 5 best discriminates among these materials. The color-composite image of these three bands unambiguously discriminates 89 percent of the mapped red volcanic cones in the three volcanic fields. Mineralogic and chemical analyses of collected samples indicate that discrimination is facilitated by the presence of hematite as a major mineral phase in the red cone basalts (hematite is only a minor mineral phase in the gray flow basalts and red sedimentary rocks).

Joint Multifractal Analysis of penetration resistance variability in an olive orchard.

NASA Astrophysics Data System (ADS)

Lopez-Herrera, Juan; Herrero-Tejedor, Tomas; Saa-Requejo, Antonio; Villeta, Maria; Tarquis, Ana M.

2016-04-01

Spatial variability of soil properties is relevant for identifying those zones with physical degradation. We used descriptive statistics and multifractal analysis for characterizing the spatial patterns of soil penetrometer resistance (PR) distributions and compare them at different soil depths and soil water content to investigate the tillage effect in soil compactation. The study was conducted on an Inceptisol dedicated to olive orchard for the last 70 years. Two parallel transects of 64 m were selected as different soil management plots, conventional tillage (CT) and no tillage (NT). Penetrometer resistance readings were carried out at 50 cm intervals within the first 20 cm of soil depth (López de Herrera et al., 2015a). Two way ANOVA highlighted that tillage system, soil depth and their interaction are statistically significant to explain the variance of PR data. The comparison of CT and NT results at different depths showed that there are significant differences deeper than 10 cm but not in the first two soil layers. The scaling properties of each PR profile was characterized by τ(q) function, calculated in the range of moment orders (q) between -5 and +5 taken at 0.5 lag increments. Several parameters were calculated from this to establish different comparisons (López de Herrera et al., 2015b). While the multifractal analysis characterizes the distribution of a single variable along its spatial support, the joint multifractal analysis can be used to characterize the joint distribution of two or more variables along a common spatial support (Kravchenko et al., 2000; Zeleke and Si, 2004). This type of analysis was performed to study the scaling properties of the joint distribution of PR at different depths. The results showed that this type of analysis added valuable information to describe the spatial arrangement of depth-dependent penetrometer data sets in all the soil layers. References Kravchenko AN, Bullock DG, Boast CW (2000) Joint multifractal analysis of crop yield and terrain slope. Agro. j. 92: 1279-1290. López de Herrera, J., Tomas Herrero Tejedor, Antonio Saa-Requejo and Ana M. Tarquis (2015a) Influence of tillage in soil penetration resistance variability in an olive orchard. Geophysical Research Abstracts, 17, EGU2015-15425. López de Herrera, J., Tomás Herrero Tejedor, Antonio Saa-Requejo, A.M. Tarquis. Influence of tillage in soil penetration resistance variability in an olive orchard. Soil Research, accepted, 2015b. doi: SR15046 Zeleke TB, Si BC (2004) Scaling properties of topographic indices and crop yield: Multifractal and joint multifractal approaches. Agro. j. 96: 1082-1090.

Quaternary basaltic volcanism in the Golden Trout Volcanic Field, southern Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Browne, Brandon L.; Becerra, Raul; Campbell, Colin; Saleen, Phillip; Wille, Frank R.

2017-09-01

The Golden Trout Volcanic Field (GTVF) produced the only Quaternary eruptions of mafic magma within the southern Sierra Nevada block. Approximately 38 × 106 m3 of basalt, trachy-basalt, basaltic trachy-andesite, and basaltic andesite (50.1-56.1% SiO2, 1.1-1.9% K2O, and 5.4-9.1% MgO) was erupted from four vents within a 10 km2 portion of the GTVF, which also includes rhyolite domes that are not considered in this study. The vents include, from oldest to youngest: Little Whitney Cone, South Fork Cone, Tunnel Cone, and unglaciated Groundhog Cone. Little Whitney Cone is a 120 m-high pile of olivine-CPX-phyric scoria produced during a Strombolian-style eruption overlying two columnar jointed lava flows. Tunnel Cone formed through a Hawaiian-style eruption along a 400 m-long north-south trending fissure that excavated at least three 25-65 m-wide craters. Crater walls up to 12 m high are composed of plagioclase-olivine-phyric spatter-fed flows that dip radially away from the crater center and crumble to form Tunnel Cone's steep unconsolidated flanks. South Fork Cone is a 170 m-high pile of plagioclase-olivine-phyric scoria that formed during Strombolian to violent Strombolian eruptions. South Fork Cone overlies the South Fork Cone lava, a 9.5 km-long flow ( 12 × 106 km3) that reached the Kern River Canyon to the west. Scoria and airfall deposits originating from South Fork Cone are located up to 2 km from the vent. Groundhog Cone is a 140 m-tall cinder and spatter cone breached on the north flank by a 13 × 106 m3 lava flow that partially buried the South Fork Cone lava and extends 7.5 km west to Kern River Canyon. Incompatible trace element concentrations and ratios show vent-specific trends but are unsystematic when plotted in terms of all mafic GTVF vents, implying that GTVF basalts were derived from a lithospheric mantle source and ascended through thick granitic Sierra Nevada crust as discrete batches that underwent different degrees of crustal contamination, differentiation, and magma mixing. Clinopyroxene-liquid thermobarometry calculations of the oldest and most primitive GTVF sample indicate that most clinopyroxene crystals record nucleation conditions of 1172-1196 °C and 896-1115 MPa. These pressures correspond to depths equivalent to, or up to 10 km shallower than, the Moho in this region. Deposits from the oldest GTVF vents are more primitive and homogeneous in terms of major and trace element concentrations, phenocryst textures and compositions, and their general absence of crustal xenoliths and xenocrysts compared to younger eruptive products. The eruption rate of the GTVF ( 0.05 km3/Myr) is two orders of magnitude less than neighboring and contemporaneous Big Pine and Coso volcanic fields to the north and east, respectively. We interpret these differences to result from a relative lack of strain in the GTVF region of the southern Sierra Nevada block, which limits magma accumulation and ascent.

Kinematics of Cone-In-Cone Growth, with Implications for Timing and Formation Mechanism

NASA Astrophysics Data System (ADS)

Hooker, J. N.; Cartwright, J. A.

2015-12-01

Cone-in-cone is an enigmatic structure. Similar to many fibrous calcite veins, cone-in-cone is generally formed of calcite and present in bedding-parallel vein-like accumulations within fine-grained rocks. Unlike most fibrous veins, cone-in-cone contains conical inclusions of host-rock material, creating nested, parallel cones throughout. A long-debated aspect of cone-in-cone structures is whether the calcite precipitated with its conical form (primary cone-in-cone), or whether the cones formed afterwards (secondary cone-in-cone). Trace dolomite within a calcite cone-in-cone structure from the Cretaceous of Jordan supports the primary hypothesis. The host sediment is a siliceous mud containing abundant rhombohedral dolomite grains. Dolomite rhombohedra are also distributed throughout the cone-in-cone. The rhombohedra within the cones are randomly oriented yet locally have dolomite overgrowths having boundaries that are aligned with calcite fibers. Evidence that dolomite co-precipitated with calcite, and did not replace calcite, includes (i) preferential downward extension of dolomite overgrowths, in the presumed growth-direction of the cone-in-cone, and (ii) planar, vertical borders between dolomite crystals and calcite fibers. Because dolomite overgrows host-sediment rhombohedra and forms fibers within the cones, it follows that the host-sediment was included within the growing cone-in-cone as the calcite precipitated, and not afterward. The host-sediment was not injected into the cone-in-cone along fractures, as the secondary-origin hypothesis suggests. This finding implies that cone-in-cone in general does not form over multiple stages, and thus has greater potential to preserve the chemical signature of its original precipitation. Because cone-in-cone likely forms before complete lithification of the host, and because the calcite displaces the host material against gravity, this chemical signature can preserve information about early overpressures in fine-grained sediments.

Swellable clay minerals in weathering products of volcanic sediments related to landslides by 2016 Kumamoto Earthquake

NASA Astrophysics Data System (ADS)

Isobe, H.; Torii, M.

2016-12-01

2016 Kumamoto Earthquake triggered numerous landslides in Aso caldera area, Japan and incurred heavy casualties. Landslides occurred not only on steep slopes at the caldera cliffs or the barranco but also on relatively gradual slopes at the side of the central cones in the Aso caldera. The Aso volcano is a volcanic complex with huge caldera formed by catastrophic eruption at approximately 90ka and central cones formed by subsequent activities to recent years. The central cones are volcanic peaks contain various rocks including basaltic, andesitic and rhoyolitic lavas and pyroclastic materials. In this study, we analyzed the samples collected from the bottom surface of landslides occurred at the gradual hillside on the western flank of the Aso central cones. The subsurface geology of the site is Takanoobane rhyolite lava, 51ka, covered by dark silty or pelitic tuffs and black soil strata including Kusasenri pumice layer, 31ka. The bottom plane of the landslides can be seen as flat surfaces at boundaries between units in the Kusasenri pumice or bottom of the Kusasenri pumice on the pelitic tuff with charcoaled plants. The Kusasenri pumice layer is a coarse grained and highly permeable but poorly continuous. X-ray diffraction analysis revealed that the main component of the samples is halloysite (10Å). Halloysite (10Å) is alteration product of fine grained volcanic ash, and swellable clay with interlayer water molecules which bring sticky and deformable characteristics. The landslides caused by 2016 Kumamoto Earthquake occurred without precipitation within a week. Strong earthquake may fluidize swellable clay layers in gradual slopes and triggered heavy landslides.

C-Arm Cone-Beam CT-Guided Transthoracic Lung Core Needle Biopsy as a Standard Diagnostic Tool

PubMed Central

Jaconi, Marta; Pagni, Fabio; Vacirca, Francesco; Leni, Davide; Corso, Rocco; Cortinovis, Diego; Bidoli, Paolo; Bono, Francesca; Cuttin, Maria S.; Valente, Maria G.; Pesci, Alberto; Bedini, Vittorio A.; Leone, Biagio E.

2015-01-01

Abstract C-arm cone-beam computed tomography (CT)-guided transthoracic lung core needle biopsy (CNB) is a safe and accurate procedure for the evaluation of patients with pulmonary nodules. This article will focus on the clinical features related to CNB in terms of diagnostic performance and complication rate. Moreover, the concept of categorizing pathological diagnosis into 4 categories, which could be used for clinical management, follow-up, and quality assurance is also introduced. We retrospectively collected data regarding 375 C-arm cone-beam CT-guided CNBs from January 2010 and June 2014. Clinical and radiological variables were evaluated in terms of success or failure rate. Pathological reports were inserted in 4 homogenous groups (nondiagnostic-L1, benign-L2, malignant not otherwise specified-L3, and malignant with specific histotype-L4), defining for each category a hierarchy of suggested actions. The sensitivity, specificity, and positive and negative predictive value and accuracy for patients subjected to CNBs were of 96.8%, 100%, 100%, 100%, and 97.2%, respectively. Roughly 75% of our samples were diagnosed as malignant, with 60% lung adenocarcinoma diagnoses. Molecular analyses were performed on 85 malignant samples to verify applicability of targeted therapy. The rate of “nondiagnostic” samples was 12%. C-arm cone-beam CT-guided transthoracic lung CNB can represent the gold standard for the diagnostic evaluation of pulmonary nodules. A clinical and pathological multidisciplinary evaluation of CNBs was needed in terms of integration of radiological, histological, and oncological data. This approach provided exceptional performances in terms of specificity, positive and negative predictive values; sensitivity in our series was lower compared with other large studies, probably due to the application of strong criteria of adequacy for CNBs (L1 class rate). The satisfactory rate of collected material was evaluated not only in terms of merely diagnostic performances but also for predictive results by molecular analysis. PMID:25816042

C-arm cone-beam CT-guided transthoracic lung core needle biopsy as a standard diagnostic tool: an observational study.

PubMed

Jaconi, Marta; Pagni, Fabio; Vacirca, Francesco; Leni, Davide; Corso, Rocco; Cortinovis, Diego; Bidoli, Paolo; Bono, Francesca; Cuttin, Maria S; Valente, Maria G; Pesci, Alberto; Bedini, Vittorio A; Leone, Biagio E

2015-03-01

C-arm cone-beam computed tomography (CT)-guided transthoracic lung core needle biopsy (CNB) is a safe and accurate procedure for the evaluation of patients with pulmonary nodules. This article will focus on the clinical features related to CNB in terms of diagnostic performance and complication rate. Moreover, the concept of categorizing pathological diagnosis into 4 categories, which could be used for clinical management, follow-up, and quality assurance is also introduced. We retrospectively collected data regarding 375 C-arm cone-beam CT-guided CNBs from January 2010 and June 2014. Clinical and radiological variables were evaluated in terms of success or failure rate. Pathological reports were inserted in 4 homogenous groups (nondiagnostic--L1, benign--L2, malignant not otherwise specified--L3, and malignant with specific histotype--L4), defining for each category a hierarchy of suggested actions. The sensitivity, specificity, and positive and negative predictive value and accuracy for patients subjected to CNBs were of 96.8%, 100%, 100%, 100%, and 97.2%, respectively. Roughly 75% of our samples were diagnosed as malignant, with 60% lung adenocarcinoma diagnoses. Molecular analyses were performed on 85 malignant samples to verify applicability of targeted therapy. The rate of "nondiagnostic" samples was 12%. C-arm cone-beam CT-guided transthoracic lung CNB can represent the gold standard for the diagnostic evaluation of pulmonary nodules. A clinical and pathological multidisciplinary evaluation of CNBs was needed in terms of integration of radiological, histological, and oncological data. This approach provided exceptional performances in terms of specificity, positive and negative predictive values; sensitivity in our series was lower compared with other large studies, probably due to the application of strong criteria of adequacy for CNBs (L1 class rate). The satisfactory rate of collected material was evaluated not only in terms of merely diagnostic performances but also for predictive results by molecular analysis.

Search for a meteoritic component at the Beaverhead impact structure, Montana

NASA Technical Reports Server (NTRS)

Lee, Pascal; Kay, Robert W.

1992-01-01

The Beaverhead impact structure, in southwestern Montana, was identified recently by the presence of shatter cones and impactites in outcrops of Proterozoic sandstones of the Belt Supergroup. The cones occur over an area greater than 100 sq km. Because the geologic and tectonic history of this region is long and complex, the outline of the original impact crater is no longer identifiable. The extent of the area over which shatter cones occur suggests, however, that the feature may have been at least 60 km in diameter. The absence of shatter cones in younger sedimentary units suggests that the impact event occurred in late Precambrian or early Paleozoic time. We have collected samples of shocked sandstone from the so-called 'Main Site' of dark-matrix breccias, and of impact breccias and melts from the south end of Island Butte. The melts, occurring often as veins through brecciated sandstone, exhibit a distinctive fluidal texture, a greenish color, and a cryptocrystalline matrix, with small inclusions of deformed sandstone. Samples of the same type, along with country rock, were analyzed previously for major- and trace-element abundances. It was found that, although the major-element composition as relatively uniform, trace-element composition showed variations between the melt material and the adjacent sandstone. These variations were attributed to extensive weathering and hydrothermal alteration. In a more specific search for a possible meteoritic signature in the breccia and the melt material we have conducted a new series of trace-element analyses on powders of our own samples by thermal neutron activation analysis. Our results indicate that Ir abundances in the breccia, the melts, and the adjacent sandstone clasts are no greater than about 0.1 ppb, suggesting no Ir enrichment of the breccia or the melts relative to the country rock. However, both the breccia and the melt material exhibit notable enrichments in Cr (8- and 10-fold), in U (9- and 5-fold), and in the heavy REE's (1.5- and 3-fold), respectively.

A superhydrophobic cone to facilitate the xenomonitoring of filarial parasites, malaria, and trypanosomes using mosquito excreta/feces.

PubMed

Cook, Darren A N; Pilotte, Nils; Minetti, Corrado; Williams, Steven A; Reimer, Lisa J

2017-11-06

Background: Molecular xenomonitoring (MX), the testing of insect vectors for the presence of human pathogens, has the potential to provide a non-invasive and cost-effective method for monitoring the prevalence of disease within a community. Current MX methods require the capture and processing of large numbers of mosquitoes, particularly in areas of low endemicity, increasing the time, cost and labour required. Screening the excreta/feces (E/F) released from mosquitoes, rather than whole carcasses, improves the throughput by removing the need to discriminate vector species since non-vectors release ingested pathogens in E/F. It also enables larger numbers of mosquitoes to be processed per pool. However, this new screening approach requires a method of efficiently collecting E/F. Methods: We developed a cone with a superhydrophobic surface to allow for the efficient collection of E/F. Using mosquitoes exposed to either Plasmodium falciparum , Brugia malayi or Trypanosoma brucei brucei, we tested the performance of the superhydrophobic cone alongside two other collection methods. Results: All collection methods enabled the detection of DNA from the three parasites. Using the superhydrophobic cone to deposit E/F into a small tube provided the highest number of positive samples (16 out of 18) and facilitated detection of parasite DNA in E/F from individual mosquitoes. Further tests showed that following a simple washing step, the cone can be reused multiple times, further improving its cost-effectiveness. Conclusions: Incorporating the superhydrophobic cone into mosquito traps or holding containers could provide a simple and efficient method for collecting E/F. Where this is not possible, swabbing the container or using the washing method facilitates the detection of the three parasites used in this study.

Low-noise cold-field emission current obtained between two opposed carbon cone nanotips during in situ transmission electron microscope biasing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knoop, L. de; Gatel, C.; Houdellier, F.

2015-06-29

A dedicated transmission electron microscope sample holder has been used to study in situ the cold-field emission process of carbon cone nanotips (CCnTs). We show that when using a CCnT instead of a Au plate-anode, the standard deviation of the emission current noise can be decreased from the 10 nA range to the 1 nA range under vacuum conditions of 10{sup −5 }Pa. This shows the strong influence of the anode on the cold-field emission current noise.

Collimated Propagation of Fast Electron Beams Accelerated by High-Contrast Laser Pulses in Highly Resistive Shocked Carbon.

PubMed

Vaisseau, X; Morace, A; Touati, M; Nakatsutsumi, M; Baton, S D; Hulin, S; Nicolaï, Ph; Nuter, R; Batani, D; Beg, F N; Breil, J; Fedosejevs, R; Feugeas, J-L; Forestier-Colleoni, P; Fourment, C; Fujioka, S; Giuffrida, L; Kerr, S; McLean, H S; Sawada, H; Tikhonchuk, V T; Santos, J J

2017-05-19

Collimated transport of ultrahigh intensity electron current was observed in cold and in laser-shocked vitreous carbon, in agreement with simulation predictions. The fast electron beams were created by coupling high-intensity and high-contrast laser pulses onto copper-coated cones drilled into the carbon samples. The guiding mechanism-observed only for times before the shock breakout at the inner cone tip-is due to self-generated resistive magnetic fields of ∼0.5-1  kT arising from the intense currents of fast electrons in vitreous carbon, by virtue of its specific high resistivity over the range of explored background temperatures. The spatial distribution of the electron beams, injected through the samples at different stages of compression, was characterized by side-on imaging of hard x-ray fluorescence.

Field Programmable Gate Array Based Parallel Strapdown Algorithm Design for Strapdown Inertial Navigation Systems

PubMed Central

Li, Zong-Tao; Wu, Tie-Jun; Lin, Can-Long; Ma, Long-Hua

2011-01-01

A new generalized optimum strapdown algorithm with coning and sculling compensation is presented, in which the position, velocity and attitude updating operations are carried out based on the single-speed structure in which all computations are executed at a single updating rate that is sufficiently high to accurately account for high frequency angular rate and acceleration rectification effects. Different from existing algorithms, the updating rates of the coning and sculling compensations are unrelated with the number of the gyro incremental angle samples and the number of the accelerometer incremental velocity samples. When the output sampling rate of inertial sensors remains constant, this algorithm allows increasing the updating rate of the coning and sculling compensation, yet with more numbers of gyro incremental angle and accelerometer incremental velocity in order to improve the accuracy of system. Then, in order to implement the new strapdown algorithm in a single FPGA chip, the parallelization of the algorithm is designed and its computational complexity is analyzed. The performance of the proposed parallel strapdown algorithm is tested on the Xilinx ISE 12.3 software platform and the FPGA device XC6VLX550T hardware platform on the basis of some fighter data. It is shown that this parallel strapdown algorithm on the FPGA platform can greatly decrease the execution time of algorithm to meet the real-time and high precision requirements of system on the high dynamic environment, relative to the existing implemented on the DSP platform. PMID:22164058

In-situ Geotechnical Investigation of Arctic Nearshore Zone Sediments, Herschel Island, Yukon

NASA Astrophysics Data System (ADS)

Stark, N.; Quinn, B.; Radosavljevic, B.; Lantuit, H.

2016-02-01

The Arctic is currently undergoing rapid changes with regard to ice coverage, permafrost retreat and coastal erosion. In addition to hydrodynamic processes, the sediments in the Arctic nearshore zone are affected by potential variations in freeze-thaw cycles, as well as an increase of abundant suspended sediment introduced by active retrogressive thaw slumps and increased river discharge. During the YUKON14 expedition to Herschel Island, Yukon, in-situ geotechnical testing of nearshore zone sediments was conducted using a portable free fall penetrometer. The research goals were mapping of sediment types, identification of surficial sediment stratification related to recent sediment remobilization or deposition processes, and the investigation of the soil mechanical characteristics of the uppermost seabed surface in the nearshore zone. Approximately 200 sites were tested using the portable free fall penetrometer, and five different geotechnical signatures identified and grouped. Most locations were characterized by a soft sediment top layer that exhibited a noticeably lower sediment strength than the underlying sediment. The results were correlated to existing sediment grain size records and a sediment type interpretation based on side scan sonar backscatter information. Strong spatial variations in sediment type and stiffness were observed, as well as in abundance and thickness of a top layer of very soft and loose sediment. It was attempted to relate the geotechnical signature to site-specific hydrodynamic energy, morphology, and vicinity to thaw slumps. The results will contribute to a detailed investigation of Arctic coastal erosion in the region, and the investigation of the role of geotechnical parameters for Arctic coastal erosion.

Eruptive Style and Geochronology of the Initial Fases of Monogenetic Vulcanism of Southern Basis of Mexico

NASA Astrophysics Data System (ADS)

Jaimes, M. D.; Martin, A.; Layer, P. W.

2013-05-01

Monogenetic vulcanism in the central part of Mexico includes the Chichinautzin Monogenetic Volcanic Field, located at the front of the Transmexican Volcanic Belt (TMVB), 300 km from the Mesoamerican trench. At least 220 volcanoes formed during the Pleistocene and Holocene. Most are scoria cones with associated lava flows, small shield volcanoes and lava domes; and cover an área of 2400 km2 (Martin Del Pozzo, 1982; Wallace and Carmichael, 1999; Velasco-Tapia and Verma, 2001; Velasco-Tapia, 2003). Previous studies in the area (paleomagnetic, geomorphologic, vulcanologic and radiometric) indicate that volcanism is less than 0.79 Ma (Bloomfield, 1973; Mooser et al., 1974; Herrero and Pal, 1978; Martin Del Pozzo et al., 1997; Siebe et al., 2004a). Our field studies include mapping and sampling of 50 lava flows associated with scoria cones, phreatomagmatic structures (2), lava flows without cones (2) and lava domes (5). Geomorphologic analyses, whole rock chemical analyse (FRX), petrographic and geochronologic (Ar-Ar) were carried out. We identified three zones with different eruptive styles: strombolian and violent strombolian to the north and south; and phreatomagmatic style only in the north. Samples are basaltic andesites to dacites. Geochronologic data is consistent with some of the relative ages according to the geomorphologic data and corresponds to three age groups.

Combined measurement of directional Raman scattering and surface-plasmon-polariton cone from adsorbates on smooth planar gold surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nyamekye, Charles K. A.; Weibel, Stephen C.; Bobbitt, Jonathan M.

Directional-surface-plasmon-coupled Raman scattering (directional RS) has the combined benefits of surface plasmon resonance and Raman spectroscopy, and provides the ability to measure adsorption and monolayer-sensitive chemical information. Directional RS is performed by optically coupling a 50-nm gold film to a Weierstrass prism in the Kretschmann configuration and scanning the angle of the incident laser under total internal reflection. The collected parameters on the prism side of the interface include a full surface-plasmon-polariton cone and the full Raman signal radiating from the cone as a function of incident angle. An instrument for performing directional RS and a quantitative study of themore » instrumental parameters are herein reported. To test the sensitivity and quantify the instrument parameters, self-assembled monolayers and 10 to 100-nm polymer films are studied. The signals are found to be well-modeled by two calculated angle-dependent parameters: three-dimensional finite-difference time-domain calculations of the electric field generated in the sample layer and projected to the far-field, and Fresnel calculations of the reflected light intensity. This is the first report of the quantitative study of the full surface-plasmon-polariton cone intensity, cone diameter, and directional Raman signal as a function of incident angle. We propose that directional RS is a viable alternative to surface plasmon resonance when added chemical information is beneficial.« less

Directing collagen fibers using counter-rotating cone extrusion.

PubMed

Hoogenkamp, Henk R; Bakker, Gert-Jan; Wolf, Louis; Suurs, Patricia; Dunnewind, Bertus; Barbut, Shai; Friedl, Peter; van Kuppevelt, Toin H; Daamen, Willeke F

2015-01-01

The bio-inspired engineering of tissue equivalents should take into account anisotropic morphology and the mechanical properties of the extracellular matrix. This especially applies to collagen fibrils, which have various, but highly defined, orientations throughout tissues and organs. There are several methods available to control the alignment of soluble collagen monomers, but the options to direct native insoluble collagen fibers are limited. Here we apply a controlled counter-rotating cone extrusion technology to engineer tubular collagen constructs with defined anisotropy. Driven by diverging inner and outer cone rotation speeds, collagen fibrils from bovine skin were extruded and precipitated onto mandrels as tubes with oriented fibers and bundles, as examined by second harmonic generation microscopy and quantitative image analysis. A clear correlation was found whereby the direction and extent of collagen fiber alignment during extrusion were a function of the shear forces caused by a combination of the cone rotation and flow direction. A gradual change in the fiber direction, spanning +50 to -40°, was observed throughout the sections of the sample, with an average decrease ranging from 2.3 to 2.6° every 10μm. By varying the cone speeds, the collagen constructs showed differences in elasticity and toughness, spanning 900-2000kPa and 19-35mJ, respectively. Rotational extrusion presents an enabling technology to create and control the (an)isotropic architecture of collagen constructs for application in tissue engineering and regenerative medicine. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Combined measurement of directional Raman scattering and surface-plasmon-polariton cone from adsorbates on smooth planar gold surfaces

DOE PAGES

Nyamekye, Charles K. A.; Weibel, Stephen C.; Bobbitt, Jonathan M.; ...

2017-09-15

Directional-surface-plasmon-coupled Raman scattering (directional RS) has the combined benefits of surface plasmon resonance and Raman spectroscopy, and provides the ability to measure adsorption and monolayer-sensitive chemical information. Directional RS is performed by optically coupling a 50-nm gold film to a Weierstrass prism in the Kretschmann configuration and scanning the angle of the incident laser under total internal reflection. The collected parameters on the prism side of the interface include a full surface-plasmon-polariton cone and the full Raman signal radiating from the cone as a function of incident angle. An instrument for performing directional RS and a quantitative study of themore » instrumental parameters are herein reported. To test the sensitivity and quantify the instrument parameters, self-assembled monolayers and 10 to 100-nm polymer films are studied. The signals are found to be well-modeled by two calculated angle-dependent parameters: three-dimensional finite-difference time-domain calculations of the electric field generated in the sample layer and projected to the far-field, and Fresnel calculations of the reflected light intensity. This is the first report of the quantitative study of the full surface-plasmon-polariton cone intensity, cone diameter, and directional Raman signal as a function of incident angle. We propose that directional RS is a viable alternative to surface plasmon resonance when added chemical information is beneficial.« less

Ion irradiation-induced easy-cone anisotropy in double-MgO free layers for perpendicular magnetic tunnel junctions

NASA Astrophysics Data System (ADS)

Teixeira, B. M. S.; Timopheev, A. A.; Caçoilo, N. F. F.; Auffret, S.; Sousa, R. C.; Dieny, B.; Alves, E.; Sobolev, N. A.

2018-05-01

We have used the ferromagnetic resonance in the X-band (9.37 GHz) to investigate the effect of 400 keV Ar+ irradiation on the perpendicular magnetic anisotropy (PMA) and Gilbert damping parameter, α, of double-MgO free layers designed for application in perpendicular magnetic tunnel junctions. The samples comprised a MgO/Fe72Co8B20/X(0.2 nm)/Fe72Co8B20/MgO layer stack, where X stands for an ultrathin Ta or W spacer. Samples with two different total FeCoB layer thicknesses, tFCB = 3.0 nm and tFCB = 2.6 nm, were irradiated with ion fluences ranging from 1012 cm-2 to 1016 cm-2. The effective first-order PMA field, BK1, decreased nearly linearly with the logarithm of the fluence for both FeCoB thicknesses and spacer elements. The decrease in BK1, which is likely caused by an ion-induced intermixing at the FeCoB/MgO interfaces, resulted in a reorientation of the magnetization of the free layers with tFCB = 2.6 nm, initially exhibiting a perpendicular easy-axis anisotropy. For intermediate fluences, 1013 cm-2 and 1014 cm-2, easy-cone states with different cone angles could be induced in the free layer with a W spacer. Importantly, no corresponding increase in the Gilbert damping was observed. This study shows that ion irradiation can be used to tune the easy-cone anisotropy in perpendicular magnetic tunnel junctions, which is interesting for spintronic applications such as spin-torque magnetic memory devices, oscillators, and sensors.

Efficacy of peracetic acid in rapid disinfection of Resilon and gutta-percha cones compared with sodium hypochlorite, chlorhexidine, and povidone-iodine.

PubMed

Subha, N; Prabhakar, V; Koshy, Minu; Abinaya, K; Prabu, M; Thangavelu, Lavanya

2013-10-01

The aim of this investigation was to compare the effectiveness of 3% sodium hypochlorite (NaOCl), 2% chlorhexidine, 1% peracetic acid, and 10% povidone-iodine in the rapid disinfection of Resilon (Pentron Clinical Technologies, LLC, Wallingford, CT) and gutta-percha cones contaminated with Enterococcus faecalis and Bacillus subtilis. Two hundred fifty-six samples consisting of 128 gutta-percha cones and 128 Resilon cones were used in this study. The materials were tested for disinfection according to the type of solution (3% NaOCl, 2% chlorhexidine, 1% peracetic acid, or 10% povidone-iodine), the time of exposure to each solution (1 or 5 minutes), and the type of microorganisms (E. faecalis or B. subtilis). Subsequent to the disinfection, samples were placed in test tubes containing 10 mL Mueller-Hinton broth and incubated at 37°C for 7 days. All test tubes were observed at 24-hour intervals and visually checked for turbidity, signifying microbial growth. In this study, 1% peracetic acid showed the best results for both 1 minute and 5 minutes of disinfection, 2% chlorhexidine showed the second best results although it was statistically at par with peracetic acid, and 3% hypochlorite ranked third in disinfection; this was statistically significant when compared with peracetic acid and chlorhexidine. Disinfection by povidone-iodine was the least within all the groups for both contact times although disinfection for 5 minutes showed better results than disinfection for 1 minute for gutta-percha. The outcome of this study confirmed the efficacy of 1% peracetic acid and 2% chlorhexidine in the rapid disinfection of both Resilon and gutta-percha. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Normal Perceptual Sensitivity Arising From Weakly Reflective Cone Photoreceptors

PubMed Central

Bruce, Kady S.; Harmening, Wolf M.; Langston, Bradley R.; Tuten, William S.; Roorda, Austin; Sincich, Lawrence C.

2015-01-01

Purpose To determine the light sensitivity of poorly reflective cones observed in retinas of normal subjects, and to establish a relationship between cone reflectivity and perceptual threshold. Methods Five subjects (four male, one female) with normal vision were imaged longitudinally (7–26 imaging sessions, representing 82–896 days) using adaptive optics scanning laser ophthalmoscopy (AOSLO) to monitor cone reflectance. Ten cones with unusually low reflectivity, as well as 10 normally reflective cones serving as controls, were targeted for perceptual testing. Cone-sized stimuli were delivered to the targeted cones and luminance increment thresholds were quantified. Thresholds were measured three to five times per session for each cone in the 10 pairs, all located 2.2 to 3.3° from the center of gaze. Results Compared with other cones in the same retinal area, three of 10 monitored dark cones were persistently poorly reflective, while seven occasionally manifested normal reflectance. Tested psychophysically, all 10 dark cones had thresholds comparable with those from normally reflecting cones measured concurrently (P = 0.49). The variation observed in dark cone thresholds also matched the wide variation seen in a large population (n = 56 cone pairs, six subjects) of normal cones; in the latter, no correlation was found between cone reflectivity and threshold (P = 0.0502). Conclusions Low cone reflectance cannot be used as a reliable indicator of cone sensitivity to light in normal retinas. To improve assessment of early retinal pathology, other diagnostic criteria should be employed along with imaging and cone-based microperimetry. PMID:26193919

Suppressing thyroid hormone signaling preserves cone photoreceptors in mouse models of retinal degeneration

PubMed Central

Ma, Hongwei; Thapa, Arjun; Morris, Lynsie; Redmond, T. Michael; Baehr, Wolfgang; Ding, Xi-Qin

2014-01-01

Cone phototransduction and survival of cones in the human macula is essential for color vision and for visual acuity. Progressive cone degeneration in age-related macular degeneration, Stargardt disease, and recessive cone dystrophies is a major cause of blindness. Thyroid hormone (TH) signaling, which regulates cell proliferation, differentiation, and apoptosis, plays a central role in cone opsin expression and patterning in the retina. Here, we investigated whether TH signaling affects cone viability in inherited retinal degeneration mouse models. Retinol isomerase RPE65-deficient mice [a model of Leber congenital amaurosis (LCA) with rapid cone loss] and cone photoreceptor function loss type 1 mice (severe recessive achromatopsia) were used to determine whether suppressing TH signaling with antithyroid treatment reduces cone death. Further, cone cyclic nucleotide-gated channel B subunit-deficient mice (moderate achromatopsia) and guanylate cyclase 2e-deficient mice (LCA with slower cone loss) were used to determine whether triiodothyronine (T3) treatment (stimulating TH signaling) causes deterioration of cones. We found that cone density in retinol isomerase RPE65-deficient and cone photoreceptor function loss type 1 mice increased about sixfold following antithyroid treatment. Cone density in cone cyclic nucleotide-gated channel B subunit-deficient and guanylate cyclase 2e-deficient mice decreased about 40% following T3 treatment. The effect of TH signaling on cone viability appears to be independent of its regulation on cone opsin expression. This work demonstrates that suppressing TH signaling in retina dystrophy mouse models is protective of cones, providing insights into cone preservation and therapeutic interventions. PMID:24550448

Enhanced techniques for the measurement of ultra-low level (pg and fg) actinide analysis by ICP-MS for forensic and geologic applications

NASA Astrophysics Data System (ADS)

Pollington, A. D.; Kinman, W.; Hanson, S. K.

2014-12-01

Recent advances in mass spectrometry have led to an improved ability to measure high precision isotope ratios at increasingly low analyte concentrations. Combining techniques for enhanced ionization with better counting of small ion beams, we routinely measure isotope ratios on 100's of pg uranium samples and ≤10 pg plutonium samples with relative standard deviations of 1‰ on major isotope ratios and 10‰ on minor ratios achievable. With slightly larger samples (≤1 ng total U), these precisions can be as low as 0.01‰ (10 ppm) and 1‰ respectively. These techniques can be applied to both nuclear forensics questions where only a small amount of sample is available, as well as geologic questions such as U-Pb or U-Th disequilibrium geochronology from either single small crystals, or microsampled domains from within a heterogeneous sample. The analytical setup is a Cetac Aridus II desolvating nebulizer interfaced with a ThermoScientific Neptune Plus equipped with a jet-type sample cone and x-type skimmer cone. The combination of the desolvating nebulizer with the enhanced cone setup leads to an increase in sensitivity on the order of 10x that of a standard glass spray chamber (~1000V/ppm U). The Neptune Plus is equipped with 9 Faraday cups and 5 electron multipliers (two behind RPQ energy filters for improved abundance sensitivtiy). This allows for the simultaneous collection of all isotopes of either U or Pu with a combination of Faraday cups (e.g., 235U and 238U) and electron multipliers (e.g., 234U and 236U) with other configurations also available (e.g., 235U and 238U can instead be measured on electron multipliers in small samples). As sample sizes get small, the contributions from environmental blanks, as well as interfering species, become increasing concerns. In this study, we will present data on efforts to minimize the contribution of environmental U using scaled down chemical procedures as well as the effect of polyatomic species on the precision and accuracy of actinide isotope measurements and what procedures can be applied to minimize interferences.

40 CFR 761.347 - First level sampling-waste from existing piles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Purposes of Characterization for PCB Disposal in Accordance With § 761.62, and Sampling PCB Remediation... a cone; that is, having a circular base with PCB bulk product waste or PCB remediation waste... one pile. If the PCB bulk product waste or PCB remediation waste consists of more than one pile or...

Micro and macroscopic investigation to quantify tillage impact on soil hydrodynamic behaviour

NASA Astrophysics Data System (ADS)

Beckers, E.; Roisin, C.; Plougonven, E.; Deraedt, D.; Léonard, A.; Degré, A.

2012-04-01

Nowadays, tillage simplification is an increasing practice. Many advantages are cited in the literature, such as energy saving, soil conservation etc. Agricultural management practices influence soil structure, but consequent changes in soil hydrodynamic behaviour at the field scale are still not well understood. Many studies focus only on macroscopic measurements which do not provide mechanistic explanations. Moreover, research shows divergent conclusions over structure modification. The aim of this work is to fill this gap by quantifying soil structure modification depending on tillage intensity through both macroscopic and microscopic measurements, the latter improving our comprehension of the fundamental mechanisms involved. Our experiment takes place in Gentinnes (Walloon Brabant, Belgium), on a field organized in a Latin square scheme. Since 2004, plots have been cultivated in conventional tillage (CT) or in reduced tillage (RT). The latter consists in sowing after stubble ploughing of about 10cm. The crop rotation is sugar beet followed by winter wheat. The soil is mainly composed of silt loam and can be classified as a Luvisol. Macroscopic investigations consist in establishing pF and K(h) curves and 3D soil strength profiles. At the microscale, 3D morphologic parameters are measured using X-ray microtomography. Because of the variation of working depth between management practices (10cm for RT vs. 25cm for CT), two horizons were investigated: H1 between 0-10cm and H2 between 12-25cm. 3D soil strength profiles were established thanks to a fully automated penetrometer (30° angle cone with a base area of 10mm2) which covered a 160 × 80cm2 area with 5cm spacing between neighbouring points. At each node, penetration was performed and soil strength measurements were collected every 1cm from 5 to 55cm depth. K(h) curves were provided by 20cm diameter tension-infiltrometer measurements (Eijkelkamp Agrisearch Equipment). Undisturbed soil samples were removed from H1 and H2 for both management practices: 100cm3 samples were used to establish pF curves with the Richards procedure, and 35cm3 samples were used for X-ray microtomography investigation. Samples for microtomography were air-dried at 40°C in order to empty meso- and macroporosity and then scanned using a Skyscan-1172 high-resolution desktop micro-CT system (Skyscan, Kontich, Belgium). Macroscopic measurements show consistent results: penetrometry profiles confirm the presence of two different horizons for RT, with a permeable superficial horizon between 0 and 10cm and a compacted subjacent horizon. Despite the long-term experiment, the old plough pan is still observed. The superficial horizon is equivalent in terms of pF curves to CT. The second horizon in RT shows significant differences with CT: porosity and especially effective porosity are greater for CT than RT. Infiltration tests confirm these reports with a higher conductivity for CT than RT. In fact, the first permeable horizon for RT is thin and the second horizon impacts vertical infiltration. These observations will be completed with microtomograms analysis. Pore size distribution, but particularly morphological parameters like eccentricity, orientation, connectivity and anisotropy of the pore network will be quantified and connected with macroscopic measurements.

Using Soil Apparent Electrical Conductivity to Optimize Sampling of Soil Penetration Resistance and to Improve the Estimations of Spatial Patterns of Soil Compaction

PubMed Central

Siqueira, Glécio Machado; Dafonte, Jorge Dafonte; Bueno Lema, Javier; Valcárcel Armesto, Montserrat; Silva, Ênio Farias França e

2014-01-01

This study presents a combined application of an EM38DD for assessing soil apparent electrical conductivity (ECa) and a dual-sensor vertical penetrometer Veris-3000 for measuring soil electrical conductivity (ECveris) and soil resistance to penetration (PR). The measurements were made at a 6 ha field cropped with forage maize under no-tillage after sowing and located in Northwestern Spain. The objective was to use data from ECa for improving the estimation of soil PR. First, data of ECa were used to determine the optimized sampling scheme of the soil PR in 40 points. Then, correlation analysis showed a significant negative relationship between soil PR and ECa, ranging from −0.36 to −0.70 for the studied soil layers. The spatial dependence of soil PR was best described by spherical models in most soil layers. However, below 0.50 m the spatial pattern of soil PR showed pure nugget effect, which could be due to the limited number of PR data used in these layers as the values of this parameter often were above the range measured by our equipment (5.5 MPa). The use of ECa as secondary variable slightly improved the estimation of PR by universal cokriging, when compared with kriging. PMID:25610899

Astronauts Young and Duke begin simulated lunar surface traverse at KSC

NASA Technical Reports Server (NTRS)

1972-01-01

Astronauts John W. Young, right, Apollo 16 commander, and Charles M. Duke Jr., lunar module pilot, prepare to begin a simulated traverse in a training area at the Kennedy Space Center (KSC). Among the experiments to fly on Apollo 16 is the soil mechanics (S-200) experiment, or self-recording penetrometer, a model of which is held here by Duke. A training model of the Lunar Roving Vehicle (LRV) is parked between the two crewmen (30694); Young and Duke maneuver a training version of the LRV about a field at KSC simulated to represent the lunar surface (30695).

Cone biopsy

MedlinePlus

... grade cone biopsy; High-grade cone biopsy; Carcinoma in situ-cone biopsy; CIS - cone biopsy; ASCUS - cone biopsy; ... marked dysplasia CIN III -- severe dysplasia to carcinoma in situ Abnormal results may also be due to cervical ...

Spectral characteristics of light sources for S-cone stimulation.

PubMed

Schlegelmilch, F; Nolte, R; Schellhorn, K; Husar, P; Henning, G; Tornow, R P

2002-11-01

Electrophysiological investigations of the short-wavelength sensitive pathway of the human eye require the use of a suitable light source as a S-cone stimulator. Different light sources with their spectral distribution properties were investigated and compared with the ideal S-cone stimulator. First, the theoretical background of the calculation of relative cone energy absorption from the spectral distribution function of the light source is summarized. From the results of the calculation, the photometric properties of the ideal S-cone stimulator will be derived. The calculation procedure was applied to virtual light sources (computer generated spectral distribution functions with different medium wavelengths and spectrum widths) and to real light sources (blue and green light emitting diodes, blue phosphor of CRT-monitor, multimedia projector, LCD monitor and notebook display). The calculated relative cone absorbencies are compared to the conditions of an ideal S-cone stimulator. Monochromatic light sources with wavelengths of less than 456 nm are close to the conditions of an ideal S-cone stimulator. Spectrum widths up to 21 nm do not affect the S-cone activation significantly (S-cone activation change < 0.2%). Blue light emitting diodes with peak wavelength at 448 nm and spectrum bandwidth of 25 nm are very useful for S-cone stimulation (S-cone activation approximately 95%). A suitable display for S-cone stimulation is the Trinitron computer monitor (S-cone activation approximately 87%). The multimedia projector has a S-cone activation up to 91%, but their spectral distribution properties depends on the selected intensity. LCD monitor and notebook displays have a lower S-cone activation (< or = 74%). Carefully selecting the blue light source for S-cone stimulation can reduce the unwanted L-and M-cone activation down to 4% for M-cones and 1.5% for L-cones.

Essential oil composition variability among natural populations of Pinus mugo Turra in Kosovo.

PubMed

Hajdari, Avni; Mustafa, Behxhet; Ahmeti, Gresa; Pulaj, Bledar; Lukas, Brigitte; Ibraliu, Alban; Stefkov, Gjoshe; Quave, Cassandra L; Novak, Johannes

2015-01-01

Pinus mugo Turra, is a native pine species in central and southern Europe, growing in high mountains area (altitudes 1.800-2.300 m.a.s.l.). In Kosovo, it is one of the native pines too, distributed in high altitudes in the Sharri Mountains and Albanian Alps Mountains. Its populations represent an important wealth of essential oil resources available, which make this species very important in terms of economic values. The chemical composition and yields of the essential oils of dwarf pine (Pinus mugo Turra) needles, twigs and cones from six wild populations in Kosovo were investigated with the aim to assess their natural variability. The identity of P. mugo was confirmed by morphology and DNA barcoding. Sixty-two compounds were identified representing 69-95 % of the total identified compounds. The yield ranged from 0.3-0.8 % v/w in needles, 1.0-2.4 % v/w in twigs and 0.1-0.5 % v/w in cones, depending on the origin of plant material and plant organs. α-Pinene (needles: 16.9-24.5 %; twigs: 4.5-8.8 %; cones: 3.1-5.6 %), β-pinene (needles: 1.5-5.4 %; twigs: 2.2-15.4 %; cones: 1.3-14.2 %), δ-3-carene (needles: 15.4-27.8 %; twigs: 24.0-51.6 %; cones: 10.5-31.5 %), limonene + β-phellandrene (needles: 1.9-5.9 %; twigs: 12.6-24.2 %; cones: 2.1-9.3 %), (E)-caryophyllene (needles: 4.4-8.9 %; twigs: 4.0-10.8 %; cones: 10.3-26.9 %) and germacrene D (needles: 4.0-8.3 %; twigs: 0.2-6.19 %; cones: 0.1-12.4 %) were the major components of the essential oil. Principal component analysis (PCA) and hierarchical cluster analyses (HCA) suggests that the population of P. mugo clustering is not related to their geographic location, but rather seemed to be linked to local selective forces acting on chemotype diversity. Low variability related to their geographic location has an economic importance since samples originating from different locations in Kosovo can treated with same standards.

Morphometric analysis - Cone beam computed tomography to predict bone quality and quantity.

PubMed

Hohlweg-Majert, B; Metzger, M C; Kummer, T; Schulze, D

2011-07-01

Modified quantitative computed tomography is a method used to predict bone quality and quantify the bone mass of the jaw. The aim of this study was to determine whether bone quantity or quality was detected by cone beam computed tomography (CBCT) combined with image analysis. MATERIALS AND PROCEDURES: Different measurements recorded on two phantoms (Siemens phantom, Comac phantom) were evaluated on images taken with the Somatom VolumeZoom (Siemens Medical Solutions, Erlangen, Germany) and the NewTom 9000 (NIM s.r.l., Verona, Italy) in order to calculate a calibration curve. The spatial relationships of six sample cylinders and the repositioning from four pig skull halves relative to adjacent defined anatomical structures were assessed by means of three-dimensional visualization software. The calibration curves for computer tomography (CT) and cone beam computer tomography (CBCT) using the Siemens phantom showed linear correlation in both modalities between the Hounsfield Units (HU) and bone morphology. A correction factor for CBCT was calculated. Exact information about the micromorphology of the bone cylinders was only available using of micro computer tomography. Cone-beam computer tomography is a suitable choice for analysing bone mass, but, it does not give any information about bone quality. 2010 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Multiple rod–cone and cone–rod photoreceptor transmutations in snakes: Evidence from visual opsin gene expression

USGS Publications Warehouse

Simoe, Bruno F; Sampaio, Filipa L.; Loew, Ellis R.; Sanders, Kate L.; Fisher, Robert N.; Hart, Nathan S.; Hunt, David M.; Partridge, Julian C.; Gower, David J.

2016-01-01

In 1934, Gordon Walls forwarded his radical theory of retinal photoreceptor ‘transmutation’. This proposed that rods and cones used for scotopic and photopic vision, respectively, were not fixed but could evolve into each other via a series of morphologically distinguishable intermediates. Walls' prime evidence came from series of diurnal and nocturnal geckos and snakes that appeared to have pure-cone or pure-rod retinas (in forms that Walls believed evolved from ancestors with the reverse complement) or which possessed intermediate photoreceptor cells. Walls was limited in testing his theory because the precise identity of visual pigments present in photoreceptors was then unknown. Subsequent molecular research has hitherto neglected this topic but presents new opportunities. We identify three visual opsin genes, rh1, sws1 and lws, in retinal mRNA of an ecologically and taxonomically diverse sample of snakes central to Walls' theory. We conclude that photoreceptors with superficially rod- or cone-like morphology are not limited to containing scotopic or photopic opsins, respectively. Walls' theory is essentially correct, and more research is needed to identify the patterns, processes and functional implications of transmutation. Future research will help to clarify the fundamental properties and physiology of photoreceptors adapted to function in different light levels.

Multiple rod–cone and cone–rod photoreceptor transmutations in snakes: evidence from visual opsin gene expression

PubMed Central

Sampaio, Filipa L.; Loew, Ellis R.; Sanders, Kate L.; Fisher, Robert N.; Hart, Nathan S.; Hunt, David M.; Partridge, Julian C.

2016-01-01

In 1934, Gordon Walls forwarded his radical theory of retinal photoreceptor ‘transmutation’. This proposed that rods and cones used for scotopic and photopic vision, respectively, were not fixed but could evolve into each other via a series of morphologically distinguishable intermediates. Walls' prime evidence came from series of diurnal and nocturnal geckos and snakes that appeared to have pure-cone or pure-rod retinas (in forms that Walls believed evolved from ancestors with the reverse complement) or which possessed intermediate photoreceptor cells. Walls was limited in testing his theory because the precise identity of visual pigments present in photoreceptors was then unknown. Subsequent molecular research has hitherto neglected this topic but presents new opportunities. We identify three visual opsin genes, rh1, sws1 and lws, in retinal mRNA of an ecologically and taxonomically diverse sample of snakes central to Walls' theory. We conclude that photoreceptors with superficially rod- or cone-like morphology are not limited to containing scotopic or photopic opsins, respectively. Walls' theory is essentially correct, and more research is needed to identify the patterns, processes and functional implications of transmutation. Future research will help to clarify the fundamental properties and physiology of photoreceptors adapted to function in different light levels. PMID:26817768

Research on the antioxidant, wound healing, and anti-inflammatory activities and the phytochemical composition of maritime pine (Pinus pinaster Ait).

PubMed

Tümen, İbrahim; Akkol, Esra Küpeli; Taştan, Hakkı; Süntar, Ipek; Kurtca, Mehmet

2018-01-30

Ethnobotanical investigations have shown that the Pinus species have been used against rheumatic pain and for wound healing in Turkish folk medicine. In this study, phytochemical composition, antioxidant, anti-inflammatory, and wound healing activities of Maritime Pine (Pinus pinaster Ait.) that is collected in Turkey are investigated. Essential oil composition and the amount of extracts (lipophilic and hydrophilic) of maritime pine wood and fresh cone samples had been tested. The essential oil from cones of P. pinaster revealed the highest activities, whereas other parts of the plant did not display any appreciable wound healing, anti-inflammatory, or antioxidant effects. α-Pinene was the main constituent of the essential oil obtained from the cones of P. pinaster. Experimental studies shown that P. pinaster's remarkable anti-inflammatory and wound healing activities support the traditional use of the plant, and suggest it could have a place in modern medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

Protective coating and hyperthermal atomic oxygen texturing of optical fibers used for blood glucose monitoring

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor)

2008-01-01

Disclosed is a method of producing cones and pillars on polymethylmethacralate (PMMA) optical fibers for glucose monitoring. The method, in one embodiment, consists of using electron beam evaporation to deposit a non-contiguous thin film of aluminum on the distal ends of the PMMA fibers. The partial coverage of aluminum on the fibers is randomly, but rather uniformly distributed across the end of the optical fibers. After the aluminum deposition, the ends of the fibers are then exposed to hyperthermal atomic oxygen, which oxidizes the areas that are not protected by aluminum. The resulting PMMA fibers have a greatly increased surface area and the cones or pillars are sufficiently close together that the cellular components in blood are excluded from passing into the valleys between the cones and pillars. The optical fibers are then coated with appropriated surface chemistry so that they can optically sense the glucose level in the blood sample than that with conventional glucose monitoring.

Moving Beam-Blocker-Based Low-Dose Cone-Beam CT

NASA Astrophysics Data System (ADS)

Lee, Taewon; Lee, Changwoo; Baek, Jongduk; Cho, Seungryong

2016-10-01

This paper experimentally demonstrates a feasibility of moving beam-blocker-based low-dose cone-beam CT (CBCT) and exploits the beam-blocking configurations to reach an optimal one that leads to the highest contrast-to-noise ratio (CNR). Sparse-view CT takes projections at sparse view angles and provides a viable option to reducing dose. We have earlier proposed a many-view under-sampling (MVUS) technique as an alternative to sparse-view CT. Instead of switching the x-ray tube power, one can place a reciprocating multi-slit beam-blocker between the x-ray tube and the patient to partially block the x-ray beam. We used a bench-top circular cone-beam CT system with a lab-made moving beam-blocker. For image reconstruction, we used a modified total-variation minimization (TV) algorithm that masks the blocked data in the back-projection step leaving only the measured data through the slits to be used in the computation. The number of slits and the reciprocation frequency have been varied and the effects of them on the image quality were investigated. For image quality assessment, we used CNR and the detectability. We also analyzed the sampling efficiency in the context of compressive sensing: the sampling density and data incoherence in each case. We tested three sets of slits with their number of 6, 12 and 18, each at reciprocation frequencies of 10, 30, 50 and 70 Hz/rot. The optimum condition out of the tested sets was found to be using 12 slits at 30 Hz/rot.

Feed-back modulation of cone synapses by L-horizontal cells of turtle retina.

PubMed

Gerschenfeld, H M; Piccolino, M; Neyton, J

1980-12-01

Light stimulation of the periphery of the receptive field of turtle cones can evoke both transient and sustained increases of the cone Ca2+ conductance, which may become regenerative. Such increase in the cone Ca2+ conductance evoked by peripheral illumination results from the activation of a polysynaptic pathway involving a feed-back connexion from the L-horizontal cells (L-HC) to the cones. Thus the hyperpolarization of a L-HC by inward current injection can evoke a Ca2+ conductance increase in neighbouring cones. The cone Ca2+ channels thus activated are likely located at its synaptic endings and probably intervene in the cone transmitter release. Therefore the feed-back connexion between L-HC and cones by modifying the Ca2+ conductance of cones could actually modulate the transmitter release from cone synapses. Such feed-back modulation of cone synapses plays a role in the organization of the colour-coded responses of the chromaticity type-horizontal cells and probably of other second order neurones, post-synaptic to the cones. The mechanisms operating the feed-back connexion from L-HC to cones are discussed.

Novel retinopathy in related Gordon setters: a clinical, behavioral, electrophysiological, and genetic investigation.

PubMed

Good, Kathryn L; Komáromy, András M; Kass, Philip H; Ofri, Ron

2016-09-01

To conduct ophthalmic, behavioral, electrophysiological, and genetic testing on two related Gordon setters presented for day blindness and compare findings with those of nine related and unrelated Gordon setters. All dogs underwent comprehensive ophthalmic examination. Maze testing was conducted under different light intensities. Rod and cone function was assessed electroretinographically. DNA samples were screened for five canine retinal disease gene mutations. Ophthalmic examination was unremarkable in all dogs. There was no notable difference between day blind dogs and the reference population in scotopic and mesopic maze tests. Day blind dogs performed worse in the photopic maze with slower course completion time and more obstacle collisions. Electroretinography revealed extinguished cone function in day blind dogs and depressed rod responses in all but two reference dogs. One reference population dog presented with day blindness 1 year after initial examination. Mutations that cause achromatopsia (in CNGB3) and cone-rod dystrophies (in ADAM9 and IQCB1) were not detected in any dog tested, although five reference dogs were carriers of the mutation in C2orf71 that causes rod-cone degeneration 4 (rcd4) in Gordon setters and in polski owczarek nizinny dogs. This report describes a novel retinopathy in related Gordon setters that has clinical signs and vision testing results consistent with achromatopsia but electroretinographic results suggestive of cone-rod dystrophy. The majority of Gordon setters in this study had low rod responses on electroretinography but it is unclear whether this was indicative of rod dysfunction or normal for the breed. Longer-term observation of affected individuals is warranted. © 2015 American College of Veterinary Ophthalmologists.

Color preference in red-green dichromats.

PubMed

Álvaro, Leticia; Moreira, Humberto; Lillo, Julio; Franklin, Anna

2015-07-28

Around 2% of males have red-green dichromacy, which is a genetic disorder of color vision where one type of cone photoreceptor is missing. Here we investigate the color preferences of dichromats. We aim (i) to establish whether the systematic and reliable color preferences of normal trichromatic observers (e.g., preference maximum at blue, minimum at yellow-green) are affected by dichromacy and (ii) to test theories of color preference with a dichromatic sample. Dichromat and normal trichromat observers named and rated how much they liked saturated, light, dark, and focal colors twice. Trichromats had the expected pattern of preference. Dichromats had a reliable pattern of preference that was different to trichromats, with a preference maximum rather than minimum at yellow and a much weaker preference for blue than trichromats. Color preference was more affected in observers who lacked the cone type sensitive to long wavelengths (protanopes) than in those who lacked the cone type sensitive to medium wavelengths (deuteranopes). Trichromats' preferences were summarized effectively in terms of cone-contrast between color and background, and yellow-blue cone-contrast could account for dichromats' pattern of preference, with some evidence for residual red-green activity in deuteranopes' preference. Dichromats' color naming also could account for their color preferences, with colors named more accurately and quickly being more preferred. This relationship between color naming and preference also was present for trichromat males but not females. Overall, the findings provide novel evidence on how dichromats experience color, advance the understanding of why humans like some colors more than others, and have implications for general theories of aesthetics.

Color preference in red–green dichromats

PubMed Central

Álvaro, Leticia; Moreira, Humberto; Lillo, Julio; Franklin, Anna

2015-01-01

Around 2% of males have red–green dichromacy, which is a genetic disorder of color vision where one type of cone photoreceptor is missing. Here we investigate the color preferences of dichromats. We aim (i) to establish whether the systematic and reliable color preferences of normal trichromatic observers (e.g., preference maximum at blue, minimum at yellow-green) are affected by dichromacy and (ii) to test theories of color preference with a dichromatic sample. Dichromat and normal trichromat observers named and rated how much they liked saturated, light, dark, and focal colors twice. Trichromats had the expected pattern of preference. Dichromats had a reliable pattern of preference that was different to trichromats, with a preference maximum rather than minimum at yellow and a much weaker preference for blue than trichromats. Color preference was more affected in observers who lacked the cone type sensitive to long wavelengths (protanopes) than in those who lacked the cone type sensitive to medium wavelengths (deuteranopes). Trichromats’ preferences were summarized effectively in terms of cone-contrast between color and background, and yellow-blue cone-contrast could account for dichromats’ pattern of preference, with some evidence for residual red–green activity in deuteranopes’ preference. Dichromats’ color naming also could account for their color preferences, with colors named more accurately and quickly being more preferred. This relationship between color naming and preference also was present for trichromat males but not females. Overall, the findings provide novel evidence on how dichromats experience color, advance the understanding of why humans like some colors more than others, and have implications for general theories of aesthetics. PMID:26170287

Surface-Cycling of Rhenium and its Isotopes

DTIC Science & Technology

2009-06-01

Fisher Scientific) in the WHOI plasma facility. Samples were introduced using a PFA MicroFlow nebulizer (Elemental Scientific Incorporated), a quartz...Samples were introduced using a PFA MicroFlow nebulizer (Elemental Scientific Incorporated), a quartz spray chamber, and regular cones. Analyses are done in...189Os. Samples dissolved in 1 mL of 0.5 molL−1 HNO3 are introduced using a PFA MicroFlow nebulizer (Elemental Scientific Incorporated), a quartz spray

Development of sampling methods for the slash pine flower thrips Gnophothrips fuscus (Morgan), (Thysanoptera: Phlaeothripidae)

Treesearch

Carl W. Fatzinger; Wayne N. Dixen

1991-01-01

Slash pine flower thrips typically destroy about 24% of the flowers (cones) present in slash pine seed orchards. The seasonal distribution and abundance of slash pine flower thrips are being investigated and methods for sampling field populations of the insect are being evaluated for potential use in integrated pest management strategies. The efficacies of several...

Foveal cone spacing and cone photopigment density difference: objective measurements in the same subjects.

PubMed

Marcos, S; Tornow, R P; Elsner, A E; Navarro, R

1997-07-01

Foveal cone spacing was measured in vivo using an objective technique: ocular speckle interferometry. Cone packing density was computed from cone spacing data. Foveal cone photopigment density difference was measured in the same subjects using retinal densitometry with a scanning laser ophthalmoscope. Both the cone packing density and cone photopigment density difference decreased sharply with increasing retinal eccentricity. From the comparison of both sets of measurements, the computed amounts of photopigment per cone increased slightly with increasing retinal eccentricity. Consistent with previous results, decreases in cone outer segment length are over-compensated by an increase in the outer segment area, at least in retinal eccentricities up to 1 deg.

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaFreniere, L. M.; Environmental Science Division

In 1992-1993, Argonne National Laboratory investigated potential carbon tetrachloride contamination that might be linked to the former grain storage facility operated by the Commodity Credit Corporation (CCC) of the U.S. Department of Agriculture (USDA) at Utica, Nebraska. These initial studies identified carbon tetrachloride in a plume of contaminated groundwater, extending approximately 3,500 ft southeastward from the former CCC/USDA facility, within a shallow upper aquifer that had been used previously as a municipal water source by the town (Figure 1.1). A deeper aquifer used as the current municipal water source was found to be free of carbon tetrachloride contamination. Although themore » shallow aquifer was no longer being used as a source of drinking water at Utica, additional studies indicated that the carbon tetrachloride could pose an unacceptable health threat to potential future residents who might install private wells along the expected downgradient migration pathway of the plume. On the basis of these findings, corrective action was recommended to decrease the carbon tetrachloride concentrations in the upper aquifer to acceptable levels (Argonne 1993a,b, 1995). Initial discussions with the Utica village board indicated that any restoration strategies involving nonbeneficial discharge of treated groundwater in the immediate vicinity of Utica would be unacceptable to the town. To address this concern, the CCC/USDA and Argonne, in cooperation with multiple federal and state regulatory and environmental agencies (Table 1.1) proposed a treatment strategy for the Utica groundwater employing groundwater extraction coupled with the seasonal use of agricultural spray irrigation equipment to simultaneously (1) remove carbon tetrachloride from the groundwater (by volatilization to the atmosphere) and (2) discharge the treated groundwater to enhance the development of wetlands in the North Lake Basin Wildlife Management Area, just north of the town (Argonne 2000). To develop this treatment approach, additional groundwater sampling was conducted to update the distribution of carbon tetrachloride in groundwater identified in the preliminary studies in 1992-1993. In March 1998, detailed mapping of the carbon tetrachloride plume was performed by using the Argonne cone penetrometer (CPT) vehicle to collect groundwater samples for analyses for volatile organic compounds (VOCs) at 13 locations (PS01-PS09, PS12, PS16, PS17, PS19; Figure 1.2). The samples were collected in vertical profiles through the aquifer, at 10-ft intervals. The results of this 1998 study (Table 1.2) demonstrated that the three-dimensional distribution of carbon tetrachloride in the aquifer is complex, with multiple 'hot spots' occurring in the plume at various depths and distances along its length (Argonne 2000). In October 2002, the CCC/USDA requested that Argonne perform targeted groundwater sampling at Utica to document the migration of the carbon tetrachloride plume since the 1998 sampling event. In February 2003, vertical-profile groundwater sampling for VOCs analyses was conducted at 8 selected locations (PS01, PS04-PS07, PS12, PS19, PS20; Figure 1.2 and Table 1.3). The lateral and vertical configuration of the carbon tetrachloride plume, as identified in the 2003 study (Argonne 2003), is illustrated in Figures 1.3-1.7. On the basis of the 2003 groundwater sampling results, a remedial system employing four extraction wells (GWEX 1-GWEX 4), with groundwater treatment by spray irrigation and conventional air stripping, was implemented at Utica, with the concurrence of the CCC/USDA and the agencies identified in Table 1.1. The principal components of the Utica system (shown in Figure 1.8) are described briefly in Section 1.2. Operation of well GWEX4 and the associated air stripper began on October 29, 2004, and routine operation of wells GWEX1-GWEX3 and the spray irrigation treatment units began on November 22, 2004.« less

Expression of the vesicular glutamate transporter vGluT2 in a subset of cones of the mouse retina.

PubMed

Wässle, Heinz; Regus-Leidig, Hanna; Haverkamp, Silke

2006-06-01

Cone photoreceptors have a continuous release of glutamate that is modulated by light. Vesicular glutamate transporters (vGluT) play an essential role for sustaining this release by loading synaptic vesicles in the cone synapse, the so-called cone pedicle. In the present study mouse retinas were immunostained for vGluT1 and vGluT2. vGluT1 was localized to all cone pedicles and rod spherules, whereas vGluT2 was found in only 10% of the cone pedicles. The vGluT2-expressing cones were characterized in more detail. They are distributed in a regular array, suggesting they are a distinct type. Their proportion does not differ between dorsal (L-cone-dominated) and ventral (S-cone-dominated) retina, and they are not the genuine blue cones of the mouse retina. During development, vGluT1 and vGluT2 expression in cones starts at around P0 and right from the beginning vGluT2 is only expressed in a subset of cones. Bipolar cells contact the vGluT2-expressing cones and other cones nonselectively. The possible functional role of vGluT2 expression in a small fraction of cones is discussed.

Comparative evaluation of the accuracy of linear measurements between cone beam computed tomography and 3D microtomography.

PubMed

Mangione, Francesca; Meleo, Deborah; Talocco, Marco; Pecci, Raffaella; Pacifici, Luciano; Bedini, Rossella

2013-01-01

The aim of this study was to evaluate the influence of artifacts on the accuracy of linear measurements estimated with a common cone beam computed tomography (CBCT) system used in dental clinical practice, by comparing it with microCT system as standard reference. Ten bovine bone cylindrical samples containing one implant each, able to provide both points of reference and image quality degradation, have been scanned by CBCT and microCT systems. Thanks to the software of the two systems, for each cylindrical sample, two diameters taken at different levels, by using implants different points as references, have been measured. Results have been analyzed by ANOVA and a significant statistically difference has been found. Due to the obtained results, in this work it is possible to say that the measurements made with the two different instruments are still not statistically comparable, although in some samples were obtained similar performances and therefore not statistically significant. With the improvement of the hardware and software of CBCT systems, in the near future the two instruments will be able to provide similar performances.

Biochemical Characterization of Cone Cyclic Nucleotide-gated (CNG) Channel Using the Infrared Fluorescence Detection System

PubMed Central

Ding, Xi-Qin; Matveev, Alexander; Singh, Anil; Komori, Naoka; Matsumoto, Hiroyuki

2012-01-01

Cone vision mediated by photoreceptor cyclic nucleotide-gated (CNG) channel is essential for central and color vision and visual acuity. Cone CNG channel is composed of two structurally related subunit types, CNGA3 and CNGB3. Naturally occurring mutations in cone CNG channel are associated with a variety of cone diseases including achromatopsia, progressive cone dystrophy, and some maculopathies. Nevertheless, our understanding of the structure of cone CNG channel is quite limited. This is, in part, due to the challenge of studying cones in a rod-dominant mammalian retina. We have demonstrated a robust expression of cone CNG channel and lack of rod CNG channel in the cone-dominant Nrl−/− retina and shown that the Nrl−/− mouse line is a valuable model to study cone CNG channel. This work examined the complex structure of cone CNG channel using infrared fluorescence Western detection combined with chemical cross-linking and blue native-PAGE. Our results suggest that the native cone CNG channel is a heterotetrameric complex likely at a stoichiometry of three CNGA3 and one CNGB3. PMID:22183405

Cone beam tomographic study of facial structures characteristics at rest and wide smile, and their correlation with the facial types.

PubMed

Martins, Luciana Flaquer; Vigorito, Julio Wilson

2013-01-01

To determine the characteristics of facial soft tissues at rest and wide smile, and their possible relation to the facial type. We analyzed a sample of forty-eight young female adults, aged between 19.10 and 40 years old, with a mean age of 30.9 years, who had balanced profile and passive lip seal. Cone beam computed tomographies were performed at rest and wide smile postures on the entire sample which was divided into three groups according to individual facial types. Soft tissue features analysis of the lips, nose, zygoma and chin were done in sagittal, axial and frontal axis tomographic views. No differences were observed in any of the facial type variables for the static analysis of facial structures at both rest and wide smile postures. Dynamic analysis showed that brachifacial types are more sensitive to movement, presenting greater sagittal lip contraction. However, the lip movement produced by this type of face results in a narrow smile, with smaller tooth exposure area when compared with other facial types. Findings pointed out that the position of the upper lip should be ahead of the lower lip, and the latter, ahead of the pogonion. It was also found that the facial type does not impact the positioning of these structures. Additionally, the use of cone beam computed tomography may be a valuable method to study craniofacial features.

Nontronite Stability in Near-Surface Sediments

NASA Astrophysics Data System (ADS)

Home, C.; Baker, L.

2015-12-01

The purpose of this study is to examine how long nontronite clays persist in soil, by studying samples collected from a sediment cone weathering out of crack in a basalt outcrop near Moscow Idaho. Nontronite, a dioctahedral ferric smectite clay, is a frequent weathering product of basaltic rocks. However, it is rarely described in surface soils, even in basaltic terrains. At our field site, nontronite formed by basalt weathering is eroding from cracks in the basalt and forming small talus cones. We are examining samples collected from a trench and several soil cores to determine the clay mineralogy at different depths in the talus cone. Bulk and clay mineralogy is being determined using X-ray Diffractometry (XRD) analysis and Fourier Transform Infrared Spectroscopy (FT-IR) analysis. Bulk chemical analyses, and selective extractions with acid oxalate and citrate-bicarbonate-dithionite reagents, are being used to analyze Fe mineralogy and amorphous constituents. Preliminary observations suggest that iron mineralogy may vary with depth in the sediments, and that older, deeper sediments may contain more Fe in oxide phases. We hypothesize that nontronite in the sediments is decomposing over time to form low-Fe smectites + Fe oxides. The results of this study will help determine whether nontronite is stable to erosion and redeposition in a surficial environment, as well as the timescale of its possible decomposition. These results may be useful in assessing proposed models of nontronite transport and redeposition on Mars.

MicroRNA528 Affects Lodging Resistance of Maize by Regulating Lignin Biosynthesis under Nitrogen-Luxury Conditions.

PubMed

Sun, Qing; Liu, Xiaogang; Yang, Juan; Liu, Wenwen; Du, Qingguo; Wang, Hongqiu; Fu, Chunxiang; Li, Wen-Xue

2018-06-04

Lodging under nitrogen (N)-luxury conditions substantially reduces crop yield and seed quality. However, the molecular mechanisms of plant lodging resistance remain largely unclear, especially in maize. We report here that the expression of ZmmiR528, a monocot-specific microRNA, is induced by N luxury but reduced by N deficiency. We show by the thioacidolysis and acetyl bromide analysis that N luxury significantly reduces the generation of H, G, and S monomers of the lignin as well as its total content in maize shoots. We further demonstrate that ZmLACCASE3 (ZmLAC3) and ZmLACCASE5 (ZmLAC5), which encode the copper-containing laccases, are the targets of ZmmiR528. In situ hybridization showed that ZmmiR528 is mainly expressed in maize vascular tissues. Knockdown of ZmmiR528 or overexpression of ZmLAC3 significantly increased the lignin content and rind penetrometer resistance of maize stems. In contrast, transgenic maize plants overexpressing ZmmiR528 had reduced lignin content and rind penetrometer resistance and were prone to lodging under N-luxury conditions. RNA-sequencing analysis revealed that ZmPAL7 and ZmPAL8 are upregulated in transgenic maize lines downregulating ZmmiR528. Under N-luxury conditions, the expression levels of ZmPALs were much higher in ZmmiR528-knockdown lines than in the wild type and transgenic maize lines overexpressing ZmmiR528. Taken together, these results indicate that, by regulating the expression of ZmLAC3 and ZmLAC5, ZmmiR528 affects maize lodging resistance under N-luxury conditions. Copyright © 2018 The Author. Published by Elsevier Inc. All rights reserved.

Snowpack spatial and temporal variability assessment using SMP high-resolution penetrometer

NASA Astrophysics Data System (ADS)

Komarov, Anton; Seliverstov, Yuriy; Sokratov, Sergey; Grebennikov, Pavel

2017-04-01

This research is focused on study of spatial and temporal variability of structure and characteristics of snowpack, quick identification of layers based on hardness and dispersion values received from snow micro penetrometer (SMP). We also discuss the detection of weak layers and definition of their parameters in non-alpine terrain. As long as it is the first SMP tool available in Russia, our intent is to test it in different climate and weather conditions. During two separate snowpack studies in plain and mountain landscapes, we derived density and grain size profiles by comparing snow density and grain size from snowpits and SMP measurements. The first case study was MSU meteorological observatory test site in Moscow. SMP data was obtained by 6 consecutive measurements along 10 m transects with a horizontal resolution of approximately 50 cm. The detailed description of snowpack structure, density, grain size, air and snow temperature was also performed. By comparing this information, the detailed scheme of snowpack evolution was created. The second case study was in Khibiny mountains. One 10-meter-long transect was made. SMP, density, grain size and snow temperature data was obtained with horizontal resolution of approximately 50 cm. The high-definition profile of snowpack density variation was acquired using received data. The analysis of data reveals high spatial and temporal variability in snow density and layer structure in both horizontal and vertical dimensions. It indicates that the spatial variability is exhibiting similar spatial patterns as surface topology. This suggests a strong influence from such factors as wind and liquid water pressure on the temporal and spatial evolution of snow structure. It was also defined, that spatial variation of snowpack characteristics is substantial even within homogeneous plain landscape, while in high-latitude mountain regions it grows significantly.

Geologic Investigations Spurred by Analog Testing at the 7504 Cone-SP Mountain Area of the San Francisco Volcanic Field

NASA Technical Reports Server (NTRS)

Eppler, Dean B.

2015-01-01

The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

Geologic Investigations Spurred by Analog Testing at the 7504 Cone-Sp Mountain Area of the San Francisco Volcanic Field

NASA Astrophysics Data System (ADS)

Bleacher, J. E.; Eppler, D. B.; Needham, D. H.; Evans, C. A.; Skinner, J. A.; Feng, W.

2015-12-01

The SP Mountain area of the San Francisco Volcanic Field, AZ, has been used as an analog mission development site for NASA since 1998. This area consists of basaltic cinder cones, lava flows and maar craters that have been active since mid-Miocene, with the youngest events occurring within the last 10,000 years. The area has been used because its geologic and topographic resemblance to lunar and Martian terrains provides an ideal venue for testing hardware and science operations practices that might be employed on planetary surfaces, as well as training astronauts in field geology. Analog operations have often led to insights that spurred new scientific investigations. Most recently, an investigation of the 7504 cone was initiated due to perceptions that Apollo-style traverse plans executed during the Desert RATS 2010 mission had characterized the area incorrectly, leading to concerns that the Apollo traverse planning process was scientifically flawed. This investigation revealed a complex history of fissure eruptions of lava and cinders, cinder cone development, a cone-fill-and-spill episode, extensive rheomorphic lava flow initiation and emplacement, and cone sector collapse that led to a final lava flow. This history was not discernible on pre-RATS mission photogeology, although independent analysis of RATS 2010 data and samples develped a "75% complete solution" that validated the pre-RATS mission planning and Apollo traverse planning and execution. The study also pointed out that the development of scientific knowledge with time in a given field area is not linear, but may follow a functional form that rises steeply in the early period of an investigation but flattens out in the later period, asymptotically approaching a theoretical "complete knowledge" point that probably cannot be achieved. This implies that future human missions must be prepared to shift geographic areas of investigation regularly if significant science returns are to be forthcoming.

Primate Short-Wavelength Cones Share Molecular Markers with Rods

PubMed Central

Craft, Cheryl M.; Huang, Jing; Possin, Daniel E.; Hendrickson, Anita

2015-01-01

Macaca, Callithrix jacchus marmoset monkey, Pan troglodytes chim- panzee and human retinas were examined to define if short wavelength (S) cones share molecular markers with L&M cone or rod photoreceptors. S cones showed consistent differences in their immunohistochemical staining and expression levels compared to L&M cones for “rod” Arrestin1 (S-Antigen), “cone” Arrestin4, cone alpha transducin, and Calbindin. Our data verify a similar pattern of expression in these primate retinas and provide clues to the structural divergence of rods and S cones versus L&M cones, suggesting S cone retinal function is “intermediate” between them. PMID:24664680

40 CFR 434.64 - Procedure and method detection limit for measurement of settleable solids.

Code of Federal Regulations, 2011 CFR

2011-07-01

... thoroughly mixed sample. Allow to settle undisturbed for 45 minutes. Gently stir along the inside surface of the cone with a stirring rod. Allow to settle undisturbed for 15 minutes longer. Record the volume of...

40 CFR 434.64 - Procedure and method detection limit for measurement of settleable solids.

Code of Federal Regulations, 2010 CFR

2010-07-01

... thoroughly mixed sample. Allow to settle undisturbed for 45 minutes. Gently stir along the inside surface of the cone with a stirring rod. Allow to settle undisturbed for 15 minutes longer. Record the volume of...

An Analysis Model for Water Cone Subsidence in Bottom Water Drive Reservoirs

NASA Astrophysics Data System (ADS)

Wang, Jianjun; Xu, Hui; Wu, Shucheng; Yang, Chao; Kong, lingxiao; Zeng, Baoquan; Xu, Haixia; Qu, Tailai

2017-12-01

Water coning in bottom water drive reservoirs, which will result in earlier water breakthrough, rapid increase in water cut and low recovery level, has drawn tremendous attention in petroleum engineering field. As one simple and effective method to inhibit bottom water coning, shut-in coning control is usually preferred in oilfield to control the water cone and furthermore to enhance economic performance. However, most of the water coning researchers just have been done on investigation of the coning behavior as it grows up, the reported studies for water cone subsidence are very scarce. The goal of this work is to present an analytical model for water cone subsidence to analyze the subsidence of water cone when the well shut in. Based on Dupuit critical oil production rate formula, an analytical model is developed to estimate the initial water cone shape at the point of critical drawdown. Then, with the initial water cone shape equation, we propose an analysis model for water cone subsidence in bottom water reservoir reservoirs. Model analysis and several sensitivity studies are conducted. This work presents accurate and fast analytical model to perform the water cone subsidence in bottom water drive reservoirs. To consider the recent interests in development of bottom drive reservoirs, our approach provides a promising technique for better understanding the subsidence of water cone.

Gene Therapy Rescues Cone Structure and Function in the 3-Month-Old rd12 Mouse: A Model for Midcourse RPE65 Leber Congenital Amaurosis

PubMed Central

Li, Xia; Li, Wensheng; Dai, Xufeng; Kong, Fansheng; Zheng, Qinxiang; Zhou, Xiangtian; Lü, Fan; Chang, Bo; Rohrer, Bärbel; Hauswirth, William. W.; Qu, Jia; Pang, Ji-jing

2011-01-01

Purpose. RPE65 function is necessary in the retinal pigment epithelium (RPE) to generate chromophore for all opsins. Its absence results in vision loss and rapid cone degeneration. Recent Leber congenital amaurosis type 2 (LCA with RPE65 mutations) phase I clinical trials demonstrated restoration of vision on RPE65 gene transfer into RPE cells overlying cones. In the rd12 mouse, a naturally occurring model of RPE65-LCA early cone degeneration was observed; however, some peripheral M-cones remained. A prior study showed that AAV-mediated RPE65 expression can prevent early cone degeneration. The present study was conducted to test whether the remaining cones in older rd12 mice can be rescued. Methods. Subretinal treatment with the scAAV5-smCBA-hRPE65 vector was initiated at postnatal day (P)14 and P90. After 2 months, electroretinograms were recorded, and cone morphology was analyzed by using cone-specific peanut agglutinin and cone opsin–specific antibodies. Results. Cone degeneration started centrally and spread ventrally, with cells losing cone-opsin staining before that for the PNA-lectin–positive cone sheath. Gene therapy starting at P14 resulted in almost wild-type M- and S-cone function and morphology. Delaying gene-replacement rescued the remaining M-cones, and most important, more M-cone opsin–positive cells were identified than were present at the onset of gene therapy, suggesting that opsin expression could be reinitiated in cells with cone sheaths. Conclusions. The results support and extend those of the previous study that gene therapy can stop early cone degeneration, and, more important, they provide proof that delayed treatment can restore the function and morphology of the remaining cones. These results have important implications for the ongoing LCA2 clinical trials. PMID:21169527

Geomorphometric variability of "monogenetic" volcanic cones: Evidence from Mauna Kea, Lanzarote and experimental cones

NASA Astrophysics Data System (ADS)

Kervyn, M.; Ernst, G. G. J.; Carracedo, J.-C.; Jacobs, P.

2012-01-01

Volcanic cones are the most common volcanic constructs on Earth. Their shape can be quantified using two morphometric ratios: the crater/cone base ratio (W cr/W co) and the cone height/width ratio (H co/W co). The average values for these ratios obtained over entire cone fields have been explained by the repose angle of loose granular material (i.e. scoria) controlling cone slopes. The observed variability in these ratios between individual cones has been attributed to the effect of erosional processes or contrasting eruptive conditions on cone morphometry. Using a GIS-based approach, high spatial resolution Digital Elevation Models and airphotos, two new geomorphometry datasets for cone fields at Mauna Kea (Hawaii, USA) and Lanzarote (Canary Islands, Spain) are extracted and analyzed here. The key observation in these datasets is the great variability in morphometric ratios, even for simple-shape and well-preserved cones. Simple analog experiments are presented to analyze factors influencing the morphometric ratios. The formation of a crater is simulated within an analog cone (i.e. a sand pile) by opening a drainage conduit at the cone base. Results from experiments show that variability in the morphometric ratios can be attributed to variations in the width, height and horizontal offset of the drainage point relative to the cone symmetry axis, to the dip of the underlying slope or to the influence of a small proportion of fine cohesive material. GIS analysis and analog experiments, together with specific examples of cones documented in the field, suggest that the morphometric ratios for well-preserved volcanic cones are controlled by a combination of 1) the intrinsic cone material properties, 2) time-dependent eruption conditions, 3) the local setting, and 4) the method used to estimate the cone height. Implications for interpreting cone morphometry solely as either an age or as an eruption condition indicator are highlighted.

Photoreceptors in a primitive mammal, the South American opossum, Didelphis marsupialis aurita: characterization with anti-opsin immunolabeling.

PubMed

Ahnelt, P K; Hokoç, J N; Röhlich, P

1995-01-01

The retinas of placental mammals appear to lack the large number and morphological diversity of cone subtypes found in diurnal reptiles. We have now studied the photoreceptor layer of a South American marsupial (Didelphis marsupialis aurita) by peanut agglutinin labeling of the cone sheath and by labeling of cone outer segments with monoclonal anti-visual pigment antibodies that have been proven to consistently label middle-to-long wavelength (COS-1) and short-wavelength (OS-2) cone subpopulations in placental mammals. Besides a dominant rod population (max. = 400,000/mm2) four subtypes of cones (max. = 3000/mm2) were identified. The outer segments of three cone subtypes were labeled by COS-1: a double cone with a principal cone containing a colorless oil droplet, a single cone with oil droplet, and another single cone. A second group of single cones lacking oil droplets was labeled by OS-2 antibody. The topography of these cone subtypes showed striking anisotropies. The COS-1 labeled single cones without oil droplets were found all over the retina and constituted the dominant population in the area centralis located in the temporal quadrant of the upper, tapetal hemisphere. The population of OS-2 labeled cones was also ubiquitous although slightly higher in the upper hemisphere (200/mm2). The COS-1 labeled cones bearing an oil droplet, including the principal member of double cones, were concentrated (800/mm2) in the inferior, non-tapetal half of the retina. The two spectral types of single cones resemble those of dichromatic photopic systems in most placental mammals. The additional set of COS-1 labeled cones is a distinct marsupial feature. The presence of oil droplets in this cone subpopulation, its absence in the area centralis, and the correlation with the non-tapetal inferior hemisphere suggest a functional specialization, possibly for mesopic conditions. Thus, sauropsid features have been retained but probably with a modified function.

UAS Collision Avoidance Algorithm that Minimizes the Impact on Route Surveillance

DTIC Science & Technology

2009-03-01

Appendix A: Collision Avoidance Algorithm/Virtual Cockpit Interface .......................124 Appendix B : Collision Cone Boundary Rates... b ) Split Cone (c) Multiple Intruders, Single and Split Cones [27] ........................................................ 27 3-3: Collision Cone...Approach in the Vertical Plane (a) Single Cone ( b ) Multiple Intruders, Single and Split Cone [27

Effect of Altered Retinal Cones/Opsins on Refractive Development under Monochromatic Lights in Guinea Pigs

PubMed Central

Zou, Leilei; Zhu, Xiaoyu; Liu, Rui; Ma, Fei; Yu, Manrong

2018-01-01

Purpose To analyze the changes of refraction and metabolism of the retinal cones under monochromatic lights in guinea pigs. Methods Sixty guinea pigs were randomly divided into a short-wavelength light (SL) group, a middle-wavelength light (ML) group, and a white light (WL) group. Refraction and axial length were measured before and after 10-week illumination. The densities of S-cones and M-cones were determined by retinal cone immunocytochemistry, and the expressions of S-opsins and M-opsins were determined by real-time PCR and Western blot. Results After 10-week illumination, the guinea pigs developed relative hyperopia in the SL group and relative myopia in the ML group. Compared with the WL group, the density of S-cones and S-opsins increased while M-cones and M-opsins decreased in the SL group (all, p < 0.05); conversely, the density of S-cones and S-opsins decreased while M-cones and M-opsins increased in the ML group (all, p < 0.05). Increased S-cones/opsins and decreased M-cones/opsins were induced by short-wavelength lights. Decreased S-cones/opsins and increased M-cones/opsins were induced by middle-wavelength lights. Conclusions Altered retinal cones/opsins induced by monochromatic lights might be involved in the refractive development in guinea pigs. PMID:29675275

The B3 Subunit of the Cone Cyclic Nucleotide-gated Channel Regulates the Light Responses of Cones and Contributes to the Channel Structural Flexibility*

PubMed Central

Ding, Xi-Qin; Thapa, Arjun; Ma, Hongwei; Xu, Jianhua; Elliott, Michael H.; Rodgers, Karla K.; Smith, Marci L.; Wang, Jin-Shan; Pittler, Steven J.; Kefalov, Vladimir J.

2016-01-01

Cone photoreceptor cyclic nucleotide-gated (CNG) channels play a pivotal role in cone phototransduction, which is a process essential for daylight vision, color vision, and visual acuity. Mutations in the cone channel subunits CNGA3 and CNGB3 are associated with human cone diseases, including achromatopsia, cone dystrophies, and early onset macular degeneration. Mutations in CNGB3 alone account for 50% of reported cases of achromatopsia. This work investigated the role of CNGB3 in cone light response and cone channel structural stability. As cones comprise only 2–3% of the total photoreceptor population in the wild-type mouse retina, we used Cngb3−/−/Nrl−/− mice with CNGB3 deficiency on a cone-dominant background in our study. We found that, in the absence of CNGB3, CNGA3 was able to travel to the outer segments, co-localize with cone opsin, and form tetrameric complexes. Electroretinogram analyses revealed reduced cone light response amplitude/sensitivity and slower response recovery in Cngb3−/−/Nrl−/− mice compared with Nrl−/− mice. Absence of CNGB3 expression altered the adaptation capacity of cones and severely compromised function in bright light. Biochemical analysis demonstrated that CNGA3 channels lacking CNGB3 were more resilient to proteolysis than CNGA3/CNGB3 channels, suggesting a hindered structural flexibility. Thus, CNGB3 regulates cone light response kinetics and the channel structural flexibility. This work advances our understanding of the biochemical and functional role of CNGB3 in cone photoreceptors. PMID:26893377

Development and Verification of Novel Porous Titanium Metaphyseal Cones for Revision Total Knee Arthroplasty.

PubMed

Faizan, Ahmad; Bhowmik-Stoker, Manoshi; Alipit, Vincent; Kirk, Amanda E; Krebs, Viktor E; Harwin, Steven F; Meneghini, R Michael

2017-06-01

Porous metaphyseal cones are widely used in revision knee arthroplasty. A new system of porous titanium metaphyseal cones has been designed based on the femoral and tibial morphology derived from a computed tomography-based anatomical database. The purpose of this study is to evaluate the initial mechanical stability of the new porous titanium revision cone system by measuring the micromotion under physiologic loading compared with a widely-used existing porous tantalum metaphyseal cone system. The new cones were designed to precisely fit the femoral and tibial anatomy, and 3D printing technology was used to manufacture these porous titanium cones. The stability of the new titanium cones and the widely-used tantalum cones were compared under physiologic loading conditions in bench top test model. The stability of the new titanium cones was either equivalent or better than the tantalum cones. The new titanium femoral cone construct had significantly less micromotion compared with the traditional femoral cone construct in 5 of the 12 directions measured (P < .05), whereas no statistical difference was found in 7 directions. The new porous titanium metaphyseal tibial cones demonstrated less micromotion in medial varus/valgus (P = .004) and posterior compressive micromotion (P = .002) compared with the traditional porous tantalum system. The findings of this biomechanical study demonstrate satisfactory mechanical stability of an anatomical-based porous titanium metaphyseal cone system for femoral and tibial bone loss as measured by micromotion under physiologic loading. The new cone design, in combination with instrumentation that facilitates surgical efficiency, is encouraging. Long-term clinical follow-up is warranted. Copyright © 2017 Elsevier Inc. All rights reserved.

Surficial Geologic Map of the West Franklin Quadrangle, Vanderburgh and Posey Counties, Indiana, and Henderson County, Kentucky

USGS Publications Warehouse

Moore, David W.; Newell, Wayne L.; Counts, Ronald C.; Fraser, Gordon S.; Fishbaugh, David A.; Brandt, Theodore R.

2007-01-01

The valley of the Ohio River is filled with alluvium and outwash (unit Qal), which total 33-39 m thick under the land surface in the southeast part of the West Franklin quadrangle in Indiana, and 30.5-35 m thick under Diamond Island in the southwest corner of the quadrangle. The deposits are chiefly fine- to medium-grained, lithic quartzose sand, interbedded by lenses of clay, clayey silt, silt, coarse sand, granules, and gravel. Although grain size of the river alluvium varies widely, in general it fines upward-being gravelly sand to sandy gravel in the lower part, mainly sand in the middle part, and silty and clayey in the upper part (Holocene). The middle and lower parts probably accumulated during the Wisconsin Episode (late Pleistocene). The sandy middle part contains interbeds of clay, silt, and minor gravel. At the base is highly consolidated mud (silt and clay), sand, and gravel 2-10 m thick. This unit may be valley train that predates the Wisconsin Episode. Creek alluvium (unit Qa) is silt, clayey silt, and subordinate intercalated fine sand, granules, and pebbles; the coarser grains are generally concentrated in the basal 1-2 m of the deposit. Lenses and beds of clay are present locally. Fossil wood collected from an auger hole in the alluvial deposits of Little Creek, at depths of 10.6 m and 6.4 m, were dated 16,650?50 and 11,120?40 radiocarbon years, respectively. Probable lacustrine terrace silt and clay (Qlt), so-called slackwater-lake or backwater deposits, form deposits 12-22 m thick in the lowest reaches of tributary creeks to the Ohio River. The surfaces of the lacustrine deposits are terraces a few meters higher than the modern creek flood plains. Covering the bedrock upland is loess (Ql) 3-7.5 m thick, deposited about 18,000-12,000 years before present. Most surficial deposits in the quadrangle are probably no older than about 35,000 yrs. Lithologic logs, shear-wave velocities, and other cone penetrometer data are used to interpret depositional environments and geologic history of the alluvium and lacustrine deposits.

Bi-directional, buried-wire skin-friction gage

NASA Technical Reports Server (NTRS)

Higuchi, H.; Peake, D. J.

1978-01-01

A compact, nonobtrusive, bi-directional, skin-friction gage was developed to measure the mean shear stress beneath a three-dimensional boundary layer. The gage works by measuring the heat flux from two orthogonal wires embedded in the surface. Such a gage was constructed and its characteristics were determined for different angles of yaw in a calibration experiment in subsonic flow with a Preston tube used as a standard. Sample gages were then used in a fully three-dimensional turbulent boundary layer on a circular cone at high relative incidence, where there were regimes of favorable and adverse pressure gradients and three-dimensional separation. Both the direction and magnitude of skin friction were then obtained on the cone surface.

The role of collapsing and cone rafting on eruption style changes and final cone morphology: Los Morados scoria cone, Mendoza, Argentina

NASA Astrophysics Data System (ADS)

Németh, Karoly; Risso, Corina; Nullo, Francisco; Kereszturi, Gabor

2011-06-01

Payún Matru Volcanic Field is a Quaternary monogenetic volcanic field that hosts scoria cones with perfect to breached morphologies. Los Morados complex is a group of at least four closely spaced scoria cones (Los Morados main cone and the older Cones A, B, and C). Los Morados main cone was formed by a long lived eruption of months to years. After an initial Hawaiian-style stage, the eruption changed to a normal Strombolian, conebuilding style, forming a cone over 150 metres high on a northward dipping (˜4°) surface. An initial cone gradually grew until a lava flow breached the cone's base and rafted an estimated 10% of the total volume. A sudden sector collapse initiated a dramatic decompression in the upper part of the feeding conduit and triggered violent a Strombolian style eruptive stage. Subsequently, the eruption became more stable, and changed to a regular Strombolian style that partially rebuilt the cone. A likely increase in magma flux coupled with the gradual growth of a new cone caused another lava flow outbreak at the structurally weakened earlier breach site. For a second time, the unstable flank of the cone was rafted, triggering a second violent Strombolian eruptive stage which was followed by a Hawaiian style lava fountain stage. The lava fountaining was accompanied by a steady outpour of voluminous lava emission accompanied by constant rafting of the cone flank, preventing the healing of the cone. Santa Maria is another scoria cone built on a nearly flat pre-eruption surface. Despite this it went through similar stages as Los Morados main cone, but probably not in as dramatic a manner as Los Morados. In contrast to these examples of large breached cones, volumetrically smaller cones, associated to less extensive lava flows, were able to heal raft/collapse events, due to the smaller magma output and flux rates. Our evidence shows that scoria cone growth is a complex process, and is a consequence of the magma internal parameters (e.g. volatile content, magma flux, recharge, output volume) and external conditions such as inclination of the pre-eruptive surface where they grew and thus gravitational instability.

A post-reconstruction method to correct cupping artifacts in cone beam breast computed tomography

PubMed Central

Altunbas, M. C.; Shaw, C. C.; Chen, L.; Lai, C.; Liu, X.; Han, T.; Wang, T.

2007-01-01

In cone beam breast computed tomography (CT), scattered radiation leads to nonuniform biasing of CT numbers known as a cupping artifact. Besides being visual distractions, cupping artifacts appear as background nonuniformities, which impair efficient gray scale windowing and pose a problem in threshold based volume visualization/segmentation. To overcome this problem, we have developed a background nonuniformity correction method specifically designed for cone beam breast CT. With this technique, the cupping artifact is modeled as an additive background signal profile in the reconstructed breast images. Due to the largely circularly symmetric shape of a typical breast, the additive background signal profile was also assumed to be circularly symmetric. The radial variation of the background signals were estimated by measuring the spatial variation of adipose tissue signals in front view breast images. To extract adipose tissue signals in an automated manner, a signal sampling scheme in polar coordinates and a background trend fitting algorithm were implemented. The background fits compared with targeted adipose tissue signal value (constant throughout the breast volume) to get an additive correction value for each tissue voxel. To test the accuracy, we applied the technique to cone beam CT images of mastectomy specimens. After correction, the images demonstrated significantly improved signal uniformity in both front and side view slices. The reduction of both intra-slice and inter-slice variations in adipose tissue CT numbers supported our observations. PMID:17822018

A New Test Method for Material Flammability Assessment in Microgravity and Extraterrestrial Environments

NASA Technical Reports Server (NTRS)

Olson, S. L.; Beeson, H. D.; Haas, J. P.; Baas, J. S.

2004-01-01

The standard oxygen consumption (cone) calorimeter (described in ASTM E 1354 and NASA STD 6001 Test 2) is modified to provide a bench-scale test environment that simulates the low velocity buoyant or ventilation flow generated by or around a burning surface in a spacecraft or extraterrestrial gravity level. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone geometry with the sample burning in a ceiling fire (stagnation flow) configuration. For a fixed radiant flux, ignition delay times for characterization material PMMA are shown to decrease by a factor of three at low stretch, demonstrating that ignition delay times determined from normal cone tests significantly underestimate the risk in microgravity. The critical heat flux for ignition is found to be lowered at low stretch as the convective cooling is reduced. At the limit of no stretch, any heat flux that exceeds the surface radiative loss at the surface ignition temperature is sufficient for ignition. Regression rates for PMMA increase with heat flux and stretch rate, but regression rates are much more sensitive to heat flux at the low stretch rates, where a modest increase in heat flux of 25 kW/m2 increases the burning rates by an order of magnitude. The global equivalence ratio of these flames is very fuel rich, and the quantity of CO produced in this configuration is significantly higher than standard cone tests. These results [2] demonstrate the ELSA apparatus allows us to conduct normal gravity experiments that accurately and quantifiably evaluate a material s flammability characteristics in the real-use environment of spacecraft or extra-terrestrial gravitational acceleration. These results also demonstrate that current NASA STD 6001 Test 2 (standard cone) is not conservative since it evaluates materials flammability with a much higher inherent buoyant convective flow.

A multi wavelength study of the circumnuclear region of NGC 1365

NASA Astrophysics Data System (ADS)

Kristen, H.; Sandqvist, A. A.; Lindblad, P. O.

We select a sample of five barred spiral galaxies in order to test previous findings concerning NGC 1365. The H I halos of the investigated objects are found to be compact. The effect of companions on the H I extent is illustrated. The central region of NGC 1365 has been mapped in the J = 3-2 CO emission line with the 15-m SEST, which has a HPBW of 15" at the frequency of this transition. The observing grid has a 5"-spacing in the inner and a 10"-spacing in the outer region. A Maximum Entropy Method (MEM) deconvolution has been performed on the inner region observations. A circumnuclear molecular torus with a radius of about 5" is the dominant feature. Molecular emission is also seen coming from various dust streamers in the bar of the galaxy. The velocity field of the molecular region agrees well with predictions of models of gas streaming in the bar and nuclear region. Comparisons with 7"-resolution VLA observations of H I absorption in the nuclear region are discussed. The morphology and kinematics of the high excitation outflow cone in the nuclear region of the Seyfert 1.5 galaxy NGC 1365 is investigated. The opening angle of the cone is 100 degrees, and the orientation such that the line of sight to the Seyfert 1.5 nucleus falls inside the cone. The outflow velocities within the cone are accelerated and fall off towards the edge. An HST FOC exposure of the nuclear region in [OIII] emission shows the cone to contain a large number of discrete clouds. Seen in the B band, a number of star forming regions surround the nucleus, of which the brightest seem to have absolute magnitudes of about -16.6 magnitudes.

Whiskers, cones and pyramids created in sputtering by ion bombardment

NASA Technical Reports Server (NTRS)

Wehner, G. K.

1979-01-01

A thorough study of the role which foreign atoms play in cone formation during sputtering of metals revealed many experimental facts. Two types of cone formation were distinquished, deposit cones and seed cones. Twenty-six combinations of metals for seed cone formation were tested. The sputtering yield variations with composition for combinations which form seed cones were measured. It was demonstrated that whisker growth becomes a common occurrence when low melting point material is sputter deposited on a hot nonsputtered high melting point electrode.

Quantifying the heterogeneity of soil compaction, physical soil properties and soil moisture across multiple spatial scales

NASA Astrophysics Data System (ADS)

Coates, Victoria; Pattison, Ian; Sander, Graham

2016-04-01

England's rural landscape is dominated by pastoral agriculture, with 40% of land cover classified as either improved or semi-natural grassland according to the Land Cover Map 2007. Since the Second World War the intensification of agriculture has resulted in greater levels of soil compaction, associated with higher stocking densities in fields. Locally compaction has led to loss of soil storage and an increased in levels of ponding in fields. At the catchment scale soil compaction has been hypothesised to contribute to increased flood risk. Previous research (Pattison, 2011) on a 40km2 catchment (Dacre Beck, Lake District, UK) has shown that when soil characteristics are homogeneously parameterised in a hydrological model, downstream peak discharges can be 65% higher for a heavy compacted soil than for a lightly compacted soil. However, at the catchment scale there is likely to be a significant amount of variability in compaction levels within and between fields, due to multiple controlling factors. This research focusses in on one specific type of land use (permanent pasture with cattle grazing) and areas of activity within the field (feeding area, field gate, tree shelter, open field area). The aim was to determine if the soil characteristics and soil compaction levels are homogeneous in the four areas of the field. Also, to determine if these levels stayed the same over the course of the year, or if there were differences at the end of the dry (October) and wet (April) periods. Field experiments were conducted in the River Skell catchment, in Yorkshire, UK, which has an area of 120km2. The dynamic cone penetrometer was used to determine the structural properties of the soil, soil samples were collected to assess the bulk density, organic matter content and permeability in the laboratory and the Hydrosense II was used to determine the soil moisture content in the topsoil. Penetration results show that the tree shelter is the most compacted and the open field area is least compacted in both periods. The falling head test showed that soil permeability was lowest around the feeding area and highest in the open field area in both periods. Laboratory tests showed that the tree shelter had the lowest bulk density values, due to the higher levels of organic matter content and the field gate had the highest levels of bulk density in both periods. There was also a significant difference in bulk density at the field gate and open field areas between the two periods. These results highlight statistically significant differences between heavily compacted areas where animals congregate and less-trampled areas of the field.

Inner Segment Remodeling and Mitochondrial Translocation in Cone Photoreceptors in Age-Related Macular Degeneration With Outer Retinal Tubulation.

PubMed

Litts, Katie M; Messinger, Jeffrey D; Freund, K Bailey; Zhang, Yuhua; Curcio, Christine A

2015-04-01

To quantify impressions of mitochondrial translocation in degenerating cones and to determine the nature of accumulated material in the subretinal space with apparent inner segment (IS)-like features by examining cone IS ultrastructure. Human donor eyes with advanced age-related macular degeneration (AMD) were screened for outer retinal tubulation (ORT) in macula-wide, high-resolution digital sections. Degenerating cones inside ORT (ORT cones) and outside ORT (non-ORT cones) from AMD eyes and unaffected cones in age-matched control eyes were imaged using transmission electron microscopy. The distances of mitochondria to the external limiting membrane (ELM), cone IS length, and cone IS width at the ELM were measured. Outer retinal tubulation and non-ORT cones lose outer segments (OS), followed by shortening of IS and mitochondria. In non-ORT cones, IS broaden. Outer retinal tubulation and non-ORT cone IS myoids become undetectable due to mitochondria redistribution toward the nucleus. Some ORT cones were found lacking IS and containing mitochondria in the outer fiber (between soma and ELM). Unlike long, thin IS mitochondria in control cones, ORT and non-ORT IS mitochondria are ovoid or reniform. Shed IS, some containing mitochondria, were found in the subretinal space. In AMD, macula cones exhibit loss of detectable myoid due to IS shortening in addition to OS loss, as described. Mitochondria shrink and translocate toward the nucleus. As reflectivity sources, translocating mitochondria may be detectable using in vivo imaging to monitor photoreceptor degeneration in retinal disorders. These results improve the knowledge basis for interpreting high-resolution clinical retinal imaging.

Determination of HCME 3-D parameters using a full ice-cream cone model

NASA Astrophysics Data System (ADS)

Na, Hyeonock; Moon, Yong-Jae; Lee, Harim

2016-05-01

It is very essential to determine three dimensional parameters (e.g., radial speed, angular width, source location) of Coronal Mass Ejections (CMEs) for space weather forecast. Several cone models (e.g., an elliptical cone model, an ice-cream cone model, an asymmetric cone model) have been examined to estimate these parameters. In this study, we investigate which cone type is close to a halo CME morphology using 26 CMEs: halo CMEs by one spacecraft (SOHO or STEREO-A or B) and as limb CMEs by the other ones. From cone shape parameters of these CMEs such as their front curvature, we find that near full ice-cream cone type CMEs are much closer to observations than shallow ice-cream cone type CMEs. Thus we develop a new cone model in which a full ice-cream cone consists of many flat cones with different heights and angular widths. This model is carried out by the following steps: (1) construct a cone for given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3-D parameters from our method are similar to those from other stereoscopic methods (a geometrical triangulation method and a Graduated Cylindrical Shell model) based on multi-spacecraft data. We are developing a general ice-cream cone model whose front shape is a free parameter determined by observations.

The uniqueness of the solution of cone-like inversion models for halo CMEs

NASA Astrophysics Data System (ADS)

Zhao, X. P.

2006-12-01

Most of elliptic halo CMEs are believed to be formed by the Thompson scattering of the photospheric light by the 3-D cone-like shell of the CME plasma. To obtain the real propagation direction and angular width of the halo CMEs, such cone-like inversion models as the circular cone, the elliptic cone and the ice-cream cone models have been suggested recently. Because the number of given parameters that are used to characterize 2-D elliptic halo CMEs observed by one spacecraft are less than the number of unknown parameters that are used to characterize the 3-D elliptic cone model, the solution of the elliptic cone model is not unique. Since it is difficult to determine whether or not an observed halo CME is formed by an circular cone or elliptic cone shell, the solution of circular cone model may often be not unique too. To fix the problem of the uniqueness of the solution of various 3-D cone-like inversion models, this work tries to develop the algorithm for using the data from multi-spacecraft, such as the STEREO A and B, and the Solar Sentinels.

N,N-Dihaloamine Explosives as Harmful Agent Defeat Materials

DTIC Science & Technology

2014-06-01

hexachloromelamine detonations .......................32 List of Figures Figure 1. Stainless steel detonation chamber...12 Figure 10. Stainless steel coupons for spore samples ....................................................................14... Stainless steel mesh (2 cm × 2 cm), as used; tube containing the screen rolled into a cone, inserted in the tube

3D Micro-tomography on Aggregates from the 2014- 2015 Eruption of Hunga Tonga-Hunga Ha'apai Volcano

NASA Astrophysics Data System (ADS)

Colombier, M.; Scheu, B.; Cronin, S. J.; Tost, M.; Dobson, K. J.; Dingwell, D. B.

2016-12-01

In December 2014- January 2015, a surtseyan eruption at Hunga Tonga-Hunga Ha'apai volcano (Tonga) formed a new island. Three main eruptive phases were distinguished by observation and deposits: (i) mound and cone construction, involving collapse of 300-600 m-high wet tephra jets, grain flows, slope-remobilisation and energetic surges, with little or no convective plume (ii) The upper cone-building phase with lower jets (mainly <300 m) but greater ash production (weak, steam-rich plumes to 6 km) and weak surges, and (iii) final phase with weak surge, fall and ballistic deposits with more vesicular pyroclasts producing proximal capping deposits. Most sampled deposits contain ash, lapilli and bombs, and lapilli-sized aggregates are ubiquitous. We used high-resolution 3D X-ray microcomputed tomography (XCT) to quantify the grain size distribution (GSD) and porosity by sampling multiple stratigraphic units within the main eruptive sequences. We visualized and quantified the internal structure of the aggregates to understand the evolution of this surtseyan eruption. We present here an overview of the textural information: porosity, vesicle size distribution and morphology as well as the variability of the aggregation features. Aggregates from the fall deposits of the early wet phase are mostly loosely packed, poorly-structured ash clusters. Aggregates from the early surge sequence and the main cone building phase dominantly exhibit a central particle coated by ash cluster material. Vesicles in the particles from the early fall deposits tend to be smaller and more isolated than in the particles from the surge sequence and the main cone building phase. The GSD of aggregates obtained by XCT is highly valuable to correct the total GSD of volcaniclastic deposits. The strong variations in the aggregation features across the eruption suggest a range of different formation and deposition mechanisms related to varying degrees of magma-water-interaction, which changed the morphology and textural properties of the individual particles.

Rates of volcanic CO2 degassing from airborne determinations of SO2 Emission rates and plume CO2SO2: test study at Pu′u ′O′o Cone, Kilauea Volcano, Hawaii

USGS Publications Warehouse

Gerlach, Terrence M.; McGee, Kenneth A.; Sutton, A. Jefferson; Elias, Tamar

1998-01-01

We present an airborne method that eliminates or minimizes several disadvantages of the customary plume cross-section sampling method for determining volcanic CO2 emission rates. A LI-COR CO2analyzer system (LICOR), a Fourier transform infrared spectrometer system (FTIR), and a correlation spectrometer (COSPEC) were used to constrain the plume CO2/SO2 and the SO2 emission rate. The method yielded a CO2 emission rate of 300 td−1 (metric tons per day) for Pu′u ′O′o cone, Kilauea volcano, on 19 September 1995. The CO2/SO2 of 0.20 determined from airborne LICOR and FTIR plume measurements agreed with the CO2/SO2 of 204 ground-based samples collected from vents over a 14-year period since the Pu′u ′O′o eruption began in January 1983.

Controllable synthesis and optical properties of novel ZnO cone arrays via vapor transport at low temperature.

PubMed

Han, Xinhai; Wang, Guanzhong; Jie, Jiansheng; Choy, Wallace C H; Luo, Yi; Yuk, T I; Hou, J G

2005-02-24

Novel ZnO cone arrays with controllable morphologies have been synthesized on silicon (100) substrates by thermal evaporation of metal Zn powder at a low temperature of 570 degrees C without a metal catalyst. Clear structure evolutions were observed using scanning electron microscopy: well-aligned ZnO nanocones, double-cones with growing head cones attached by stem cones, and cones with straight hexagonal pillar were obtained as the distance between the source and the substrates was increased. X-ray diffraction shows that all cone arrays grow along the c-axis. Raman and photoluminescence spectra reveal that the optical properties of the buffer layer between the ZnO cone arrays and the silicon substrates are better than those of the ZnO cone arrays due to high concentration of Zn in the heads of the ZnO cone arrays and higher growth temperature of the buffer layer. The growth of ZnO arrays reveals that the cone arrays are synthesized through a self-catalyzed vapor-liquid-solid (VLS) process.

Variability in bleach kinetics and amount of photopigment between individual foveal cones.

PubMed

Bedggood, Phillip; Metha, Andrew

2012-06-20

To study the bleaching dynamics of individual foveal cone photoreceptors using an adaptive optics ophthalmoscope. After dark adaptation, cones were progressively bleached and imaged by a series of flashes of 545-nm to 570-nm light at 12 Hz. Intensity measurements were made within the foveal avascular zone (FAZ) to avoid confounding signals from the inner retinal blood supply. Over 1300 cones in this region were identified and tracked through the imaging sequences. A single subject was used who demonstrated the necessary steady fixation, wide FAZ, and resolvability of cones close to the foveal center. The mean intensity of all cones was well-described by first-order kinetics. Individual cones showed marked differences from the mean, both in rate of bleach and amount of photopigment; there was an inverse correlation between these two parameters. A subset of the cones showed large oscillations in intensity consistent with interference from light scattered within the cone outer segment. These cones also bleached more quickly, implying that rapid bleaching induces greater amounts of scatter. Neighboring cones in the fovea display high variability in their optical properties.

An Evaluation of GuttaFlow2 in Filling Artificial Internal Resorption Cavities: An in vitro Study.

PubMed

Mohammad, Yara; Alafif, Hisham; Hajeer, Mohammad; Yassin, Oula

2016-06-01

Obturation of root canal with internal resorption represents a major challenge in Endodontics. In spite of that, usual obturation techniques are often employed without considering the best technique to solve this problem. The goal of this study was to investigate the ability of GuttaFlow2 in filling artificial internal resorption cavities. The study sample included 36 human upper central incisors that were prepared using Protaper system (F4). Internal resorption cavities were prepared by cutting each tooth at 7 mm from the apex and preparing hemispherical cavities on both the sides and then re-attaching them. The sample was randomly separated into three groups (n = 12 in each group). In the first group, thermal injection technique (Obtura II) was employed and served as the control group. In the second group, injection of cold free-flow obturation technique with a master cone (GF2-C) was employed, whereas in the third group injection of cold free-flow obturation without a master cone (GF2) was followed. The teeth were re-cut at the same level as before and examined under a stereomicroscope. Subsequently, the captured images were transferred to AutoCAD program to measure the percentage of total filling "TF," gutta-percha "G," sealer "S," and voids "V" out of the total surface of the cross sections. All materials showed high filling properties in terms of "total filling," ranging from 99.17% (for Obtura II) to 99.72% (for GF2-C). Regarding gutta-percha percentages of filling, they ranged from 83.15 to 83.93%, whereas those for the sealer ranged from 5.71 to 15.24%. GuttaFlow2 group with a master cone appeared to give the best results despite the insignificant differences among the three groups. The GuttaFlow2 with a master cone technique seemed to be a promising filling material and gave results similar to those observed with Obtura II. It is recommended for use to obturate internal resorption cavities in clinical practice due to its good adaptability to root canal walls, ease of handling, and application. Internal resorption defects can be successfully filled with GuttaFlow2 material when supplemented with a master cone, and the results are comparable with those obtained with the Obtura II technique.

Reconstruction of glacial lake outburst floods in northern Tien Shan: Implications for hazard assessment

NASA Astrophysics Data System (ADS)

Zaginaev, V.; Ballesteros-Cánovas, J. A.; Erokhin, S.; Matov, E.; Petrakov, D.; Stoffel, M.

2016-09-01

Glacier lake outburst floods (GLOFs) and related debris flows are among the most significant natural threats in the Tien Shan Mountains of Kyrgyzstan and have even caused the loss of life and damage to infrastructure in its capital Bishkek. An improved understanding of the occurrence of this process is essential so as to be able to design reliable disaster risk reduction strategies, even more so in view of ongoing climate change and scenarios of future evolutions. Here, we apply a dendrogeomorphic approach to reconstruct past debris-flow activity on the Aksay cone (Ala-Archa valley, Kyrgyz range), where outbursting glacier lakes and intense rainfalls have triggered huge debris flows over the past decades. A total of 96 Picea abies (L.) Karst. trees growing on the cone and along the main channel have been selected based on the evidence of past debris-flow damage in their trunks; these trees were then sampled using increment borers. The dating of past events was based on the assessment of growth disturbances (GD) in the tree-ring records and included the detection of injuries, tangential rows of traumatic resin ducts, reaction wood, and abrupt growth changes. In total, 320 GD were identified in the tree-ring samples. In combination with aerial imagery and geomorphic recognition in the field, reactions in trees and their position on the cone have allowed reconstruction of the main spatial patterns of past events on the Aksay cone. Our findings suggest that at least 27 debris flows have occurred on the site between 1877 and 2015 and point to the occurrence of at least 17 events that were not documented prior to this study. We also observe high process activity during the 1950s and 1960s, with major events on the cone in 1950, 1966, and 1968, coinciding with phases of slight glacier advance. The spatial analyses of events also point to two different spatial patterns, suggesting that quite dissimilar magnitudes probably occurred during glacier lake outburst floods and rainfall-induced debris-flow events. The results presented here represent the longest, annually resolved GLOF series in the region, which in turn has key implications on risk assessment, not just in the Ala-Archa valley, but also in the entire Kyrgyz range (northern Tien Shan).

Nontraumatic tibial polyethylene insert cone fracture in mobile-bearing posterior-stabilized total knee arthroplasty.

PubMed

Tanikake, Yohei; Hayashi, Koji; Ogawa, Munehiro; Inagaki, Yusuke; Kawate, Kenji; Tomita, Tetsuya; Tanaka, Yasuhito

2016-12-01

A 72-year-old male patient underwent mobile-bearing posterior-stabilized total knee arthroplasty for osteoarthritis. He experienced a nontraumatic polyethylene tibial insert cone fracture 27 months after surgery. Scanning electron microscopy of the fracture surface of the tibial insert cone suggested progress of ductile breaking from the posterior toward the anterior of the cone due to repeated longitudinal bending stress, leading to fatigue breaking at the anterior side of the cone, followed by the tibial insert cone fracture at the anterior side of the cone, resulting in fracture at the base of the cone. This analysis shows the risk of tibial insert cone fracture due to longitudinal stress in mobile-bearing posterior-stabilized total knee arthroplasty in which an insert is designed to highly conform to the femoral component.

Spatiochromatic Interactions between Individual Cone Photoreceptors in the Human Retina

PubMed Central

Sabesan, Ramkumar; Sincich, Lawrence C.

2017-01-01

A remarkable feature of human vision is that the retina and brain have evolved circuitry to extract useful spatial and spectral information from signals originating in a photoreceptor mosaic with trichromatic constituents that vary widely in their relative numbers and local spatial configurations. A critical early transformation applied to cone signals is horizontal-cell-mediated lateral inhibition, which imparts a spatially antagonistic surround to individual cone receptive fields, a signature inherited by downstream neurons and implicated in color signaling. In the peripheral retina, the functional connectivity of cone inputs to the circuitry that mediates lateral inhibition is not cone-type specific, but whether these wiring schemes are maintained closer to the fovea remains unsettled, in part because central retinal anatomy is not easily amenable to direct physiological assessment. Here, we demonstrate how the precise topography of the long (L)-, middle (M)-, and short (S)-wavelength-sensitive cones in the human parafovea (1.5° eccentricity) shapes perceptual sensitivity. We used adaptive optics microstimulation to measure psychophysical detection thresholds from individual cones with spectral types that had been classified independently by absorptance imaging. Measured against chromatic adapting backgrounds, the sensitivities of L and M cones were, on average, receptor-type specific, but individual cone thresholds varied systematically with the number of preferentially activated cones in the immediate neighborhood. The spatial and spectral patterns of these interactions suggest that interneurons mediating lateral inhibition in the central retina, likely horizontal cells, establish functional connections with L and M cones indiscriminately, implying that the cone-selective circuitry supporting red–green color vision emerges after the first retinal synapse. SIGNIFICANCE STATEMENT We present evidence for spatially antagonistic interactions between individual, spectrally typed cones in the central retina of human observers using adaptive optics. Using chromatic adapting fields to modulate the relative steady-state activity of long (L)- and middle (M)-wavelength-sensitive cones, we found that single-cone detection thresholds varied predictably with the spectral demographics of the surrounding cones. The spatial scale and spectral pattern of these photoreceptor interactions were consistent with lateral inhibition mediated by retinal horizontal cells that receive nonselective input from L and M cones. These results demonstrate a clear link between the neural architecture of the visual system inputs—cone photoreceptors—and visual perception and have implications for the neural locus of the cone-specific circuitry supporting color vision. PMID:28871030

Distribution of Pb-210 in Spanish Soils: Study of the Atmospheric Contribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrera, M.; Romero, M. L.; Valino, F.

The vertical distribution of activity and inventories of atmospheric Pb-210 is being studied in Spanish soils, aiming to establish the reference levels in the zone, based on the type of soil and the annual rainfall. A homogeneous distribution grid (approx. 150x150 km each cell) has been established covering the peninsular land, trying to combine the varying soil types (remaining undisturbed for the last 50 years) and the closeness to meteorological stations. Sampling has been performed by extracting undisturbed soil cylinders of 6 cm diameter and 120 cm length, with an impact penetrometer, and the soil cores have been sectioned inmore » slices of 3 cm thick. The analysis of Pb-210 has been performed using a gamma spectrometry system with coaxial HPGe detector sensitive at low energies (46.5 keV emission). The geometry of measured samples is thin enough (approx. 2 cm) to minimize self-absorption corrections. The work presents the results obtained so far. The Pb-210 activity profiles exhibit the characteristic decreasing shape with depth, showing maximum levels at the surface, and reaching the equilibrium activity with Ra-226 at a maximum depth depending on different environmental conditions. The unsupported Pb-210 inventory values are in the usual range (1000-5000 Bq/m{sup 2}), showing a positive correlation with the averaged annual rainfall. These reference levels could be used in posterior studies of anthropogenic alteration of soils, evaluation of erosion and desertification processes.« less

The Na+/Ca2+, K+ exchanger NCKX4 is required for efficient cone-mediated vision.

PubMed

Vinberg, Frans; Wang, Tian; De Maria, Alicia; Zhao, Haiqing; Bassnett, Steven; Chen, Jeannie; Kefalov, Vladimir J

2017-06-26

Calcium (Ca 2+ ) plays an important role in the function and health of neurons. In vertebrate cone photoreceptors, Ca 2+ controls photoresponse sensitivity, kinetics, and light adaptation. Despite the critical role of Ca 2+ in supporting the function and survival of cones, the mechanism for its extrusion from cone outer segments is not well understood. Here, we show that the Na + /Ca 2+ , K + exchanger NCKX4 is expressed in zebrafish, mouse, and primate cones. Functional analysis of NCKX4-deficient mouse cones revealed that this exchanger is essential for the wide operating range and high temporal resolution of cone-mediated vision. We show that NCKX4 shapes the cone photoresponse together with the cone-specific NCKX2: NCKX4 acts early to limit response amplitude, while NCKX2 acts late to further accelerate response recovery. The regulation of Ca 2+ by NCKX4 in cones is a novel mechanism that supports their ability to function as daytime photoreceptors and promotes their survival.

Activated mTORC1 promotes long-term cone survival in retinitis pigmentosa mice

PubMed Central

Venkatesh, Aditya; Ma, Shan; Le, Yun Z.; Hall, Michael N.; Rüegg, Markus A.; Punzo, Claudio

2015-01-01

Retinitis pigmentosa (RP) is an inherited photoreceptor degenerative disorder that results in blindness. The disease is often caused by mutations in genes that are specific to rod photoreceptors; however, blindness results from the secondary loss of cones by a still unknown mechanism. Here, we demonstrated that the mammalian target of rapamycin complex 1 (mTORC1) is required to slow the progression of cone death during disease and that constitutive activation of mTORC1 in cones is sufficient to maintain cone function and promote long-term cone survival. Activation of mTORC1 in cones enhanced glucose uptake, retention, and utilization, leading to increased levels of the key metabolite NADPH. Moreover, cone death was delayed in the absence of the NADPH-sensitive cell death protease caspase 2, supporting the contribution of reduced NADPH in promoting cone death. Constitutive activation of mTORC1 preserved cones in 2 mouse models of RP, suggesting that the secondary loss of cones is caused mainly by metabolic deficits and is independent of a specific rod-associated mutation. Together, the results of this study address a longstanding question in the field and suggest that activating mTORC1 in cones has therapeutic potential to prolong vision in RP. PMID:25798619

Analysis of axial spatial resolution in a variable resolution x-ray cone beam CT (VRX-CBCT) system

NASA Astrophysics Data System (ADS)

Dahi, Bahram; Keyes, Gary S.; Rendon, David A.; DiBianca, Frank A.

2008-03-01

The Variable Resolution X-ray (VRX) technique has been successfully used in a Cone-Beam CT (CBCT) system to increase the spatial resolution of CT images in the transverse plane. This was achieved by tilting the Flat Panel Detector (FPD) to smaller vrx y angles in a VRX Cone Beam CT (VRX-CBCT) system. In this paper, the effect on the axial spatial resolution of CT images created by the VRX-CBCT system is examined at different vrx x angles, where vrx x is the tilting angle of the FPD about its x-axis. An amorphous silicon FPD with a CsI scintillator is coupled with a micro-focus x-ray tube to form a CBCT. The FPD is installed on a rotating frame that allows rotation of up to 90° about x and y axes of the FPD. There is no rotation about the z-axis (i.e. normal to the imaging surface). Tilting the FPD about its x-axis (i.e. decreasing the vrx x angle) reduces both the width of the line-spread function and the sampling distance by a factor of sin vrx x, thereby increasing the theoretical detector pre-sampling spatial resolution proportionately. This results in thinner CT slices that in turn help increase the axial spatial resolution of the CT images. An in-house phantom is used to measure the MTF of the reconstructed CT images at different vrx x angles.

Worldwide Prevalence of Mandibular Second Molar C-Shaped Morphologies Evaluated by Cone-Beam Computed Tomography.

PubMed

von Zuben, Murilo; Martins, Jorge N R; Berti, Luiza; Cassim, Imran; Flynn, Daniel; Gonzalez, Jose Antonio; Gu, Yongchun; Kottoor, Jojo; Monroe, Adam; Rosas Aguilar, Rubén; Marques, Miguel Seruca; Ginjeira, António

2017-09-01

The aim of this study was to evaluate and compare the C-shaped mandibular second molar prevalence in different regions around the world with the aid of cone-beam computed tomography technology. Nine field observers from 9 different geographic regions were calibrated. A total of 400 samples were collected in each region. The prevalence of C-shaped anatomy was calculated. The number of roots and the configuration of the C-shaped canals at 3 different axial levels were also evaluated. The z-test was used to analyze the difference between the means of each independent group. Intrarater reliability was also tested. A total of 3600 teeth from 2735 patients were included in this research; 499 teeth presented C-shaped root canal configuration, representing a global prevalence of 13.9%. China had a prevalence of 44.0%, which was significantly higher than any other region. The C-shape prevalence in women was 16.5%, which was significantly higher than the 10.4% prevalence found in men. No difference between sides (37 or 47) was evident in the global sample. Cone-beam computed tomography is a valuable tool to evaluate the C-shaped root canal configuration in vivo. In the present study, China presented the highest prevalence of C-shaped mandibular second molars when compared with other regions. Women exhibited a higher prevalence than men. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

High Resolution Studies of the Origins of Polyatomic Ions in Inductively Coupled Plasma-Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferguson, Jill Wisnewski

2006-01-01

The inductively coupled plasma (ICP) is an atmospheric pressure ionization source. Traditionally, the plasma is sampled via a sampler cone. A supersonic jet develops behind the sampler, and this region is pumped down to a pressure of approximately one Torr. A skimmer cone is located inside this zone of silence to transmit ions into the mass spectrometer. The position of the sampler and skimmer cones relative to the initial radiation and normal analytical zones of the plasma is key to optimizing the useful analytical signal [1]. The ICP both atomizes and ionizes the sample. Polyatomic ions form through ion-molecule interactionsmore » either in the ICP or during ion extraction [l]. Common polyatomic ions that inhibit analysis include metal oxides (MO +), adducts with argon, the gas most commonly used to make up the plasma, and hydride species. While high resolution devices can separate many analytes from common interferences, this is done at great cost in ion transmission efficiency--a loss of 99% when using high versus low resolution on the same instrument [2]. Simple quadrupole devices, which make up the bulk of ICP-MS instruments in existence, do not present this option. Therefore, if the source of polyatomic interferences can be determined and then manipulated, this could potentially improve the figures of merit on all ICP-MS devices, not just the high resolution devices often utilized to study polyatomic interferences.« less

Early-onset, slow progression of cone photoreceptor dysfunction and degeneration in CNG channel subunit CNGB3 deficiency.

PubMed

Xu, Jianhua; Morris, Lynsie; Fliesler, Steven J; Sherry, David M; Ding, Xi-Qin

2011-06-01

To investigate the progression of cone dysfunction and degeneration in CNG channel subunit CNGB3 deficiency. Retinal structure and function in CNGB3(-/-) and wild-type (WT) mice were evaluated by electroretinography (ERG), lectin cytochemistry, and correlative Western blot analysis of cone-specific proteins. Cone and rod terminal integrity was assessed by electron microscopy and synaptic protein immunohistochemical distribution. Cone ERG amplitudes (photopic b-wave) in CNGB3(-/-) mice were reduced to approximately 50% of WT levels by postnatal day 15, decreasing further to approximately 30% of WT levels by 1 month and to approximately 20% by 12 months of age. Rod ERG responses (scotopic a-wave) were not affected in CNGB3(-/-) mice. Average CNGB3(-/-) cone densities were approximately 80% of WT levels at 1 month and declined slowly thereafter to only approximately 50% of WT levels by 12 months. Expression levels of M-opsin, cone transducin α-subunit, and cone arrestin in CNGB3(-/-) mice were reduced by 50% to 60% by 1 month and declined to 35% to 45% of WT levels by 9 months. In addition, cone opsin mislocalized to the outer nuclear layer and the outer plexiform layer in the CNGB3(-/-) retina. Cone and rod synaptic marker expression and terminal ultrastructure were normal in the CNGB3(-/-) retina. These findings are consistent with an early-onset, slow progression of cone functional defects and cone loss in CNGB3(-/-) mice, with the cone signaling deficits arising from disrupted phototransduction and cone loss rather than from synaptic defects.

Allozyme differentiation and biosystematics of the Californian closed-cone pines (Pinus subsect. Oocarpae)

Treesearch

Constance I. Millar; Steven H. Strauss; M. Thompson Conkle; Robert D. Westfall

1988-01-01

Allozyme differentiation at 32 loci was studied in the three Californian species of Pinus subsect. Oocarpae: P. attenuata, P. muricata, and P. radiata, and in a small sample of a Latin American species of the subsection, P. oocarpa. The Californian species...

Distribution and specificity of S-cone ("blue cone") signals in subcortical visual pathways.

PubMed

Martin, Paul R; Lee, Barry B

2014-03-01

We review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset monkeys. We discuss segregation of S-cone recipient (blue-on and blue-off) receptive fields in the dorsal lateral geniculate nucleus and describe their receptive field properties. We treat in some detail the question of detecting weak S-cone signals as an introduction for newcomers to the field. Finally, we briefly consider the question on how S-cone signals are distributed among nongeniculate targets.

Temporal and spatial characteristics of cone degeneration in RCS rats.

PubMed

Huang, Yan Ming; Yin, Zheng Qin; Liu, Kang; Huo, Shu Jia

2011-03-01

The temporal and spatial characteristics of cone degeneration in the Royal College of Surgeons (RCS) rat were studied to provide information for treatment strategies of retinitis pigmentosa. Nonpigmented dystrophic RCS rats (RCS) and pigmented nondystrophic RCS rats (controls) were used. Cone processes were visualized with peanut agglutinin (PNA). Cone development appears to have been completed by postnatal day 21 (P21) in both the RCS and control rats. Signs of cone degeneration were obvious by P30, with shorter outer segments (OSs) and enlarged inner segments (ISs). At that time, 81.7% of the cones retained stained ISs. The rate of IS density decline was slower in the peripheral, nasal, and superior retina, and only 43.6% of the cones with ISs were present at P45. By P60, PNA-labeled cone ISs were distorted and restricted to the peripheral retina, and by P90, few cone pedicles were detected. Our findings indicate that therapeutic strategies aimed at rescuing cones in the degenerating retina should be applied before P21 and no later than P45 while substantial numbers of cones retain their ISs. Either the middle or peripheral regions of the nasal and superior retina are the best locations for transplantation strategies.

Ion Clouds in the Inductively Coupled Plasma Torch: A Closer Look through Computations.

PubMed

Aghaei, Maryam; Lindner, Helmut; Bogaerts, Annemie

2016-08-16

We have computationally investigated the introduction of copper elemental particles in an inductively coupled plasma torch connected to a sampling cone, including for the first time the ionization of the sample. The sample is inserted as liquid particles, which are followed inside the entire torch, i.e., from the injector inlet up to the ionization and reaching the sampler. The spatial position of the ion clouds inside the torch as well as detailed information on the copper species fluxes at the position of the sampler orifice and the exhausts of the torch are provided. The effect of on- and off-axis injection is studied. We clearly show that the ion clouds of on-axis injected material are located closer to the sampler with less radial diffusion. This guarantees a higher transport efficiency through the sampler cone. Moreover, our model reveals the optimum ranges of applied power and flow rates, which ensure the proper position of ion clouds inside the torch, i.e., close enough to the sampler to increase the fraction that can enter the mass spectrometer and with minimum loss of material toward the exhausts as well as a sufficiently high plasma temperature for efficient ionization.

Fracture surface analysis of a quenched (α+β)-metastable titanium alloy

NASA Astrophysics Data System (ADS)

Illarionov, A. G.; Stepanov, S. I.; Demakov, S. L.

2017-12-01

Fracture surface analysis is conducted by means of SEM for VT16 titanium alloy specimens solution-treated at temperatures ranging from 700 to 875 °C, water-quenched and subjected to tensile testing. A cup and cone shape failure and dimple microstructure of the fracture surface indicates the ductile behavior of the alloy. Dimple dimensions correlated with the β-grain size of the alloy in quenched condition. The fracture area (namely, the size; the cup and cone shape) depends on the volume fraction of the primary α-phase in the quenched sample. However, the fracture surface changes considerably when the strain-induced β-αʺ-transformation takes place during tensile testing, resulting in the increase of alloy ductility.

Siblings for SETI

NASA Astrophysics Data System (ADS)

Frisch, D.; Melia, F.

1983-09-01

The SAO Catalog of about 260,000 stars was studied to arrive at a sample of 'sibling', sun-like G-stars whose possible planetary systems' intelligent beings might feel drawn to single out each other for directional listening and broadcasting. A set of mostly untabulated sibling candidate stars can be defined, given a direction and a small solid angle that are mutually interesting to members of that set, so that overlapping broadcast/receiving cones can be selected on the basis of commonality. It is suggested that the double cone about the direction of the galactic center, whose half angle is 1/137 radian, is an almost inevitable choice in which sending and receiving with current technology can reach to about 1 kpsc, yielding an estimated 1000 G-star sibling candidates.

MBARI's 2001 Hawaii Expedition using the R/V Western Flyer and ROV Tiburon

NASA Astrophysics Data System (ADS)

Clague, D. A.; Paull, C. K.; Greene, H. G.; Jordahl, K.; Davis, A. S.

2001-12-01

The MBARI research vessel Western Flyer with the Tiburon remotely operated vehicle (ROV) spent 36 days at sea doing mainly geologic investigations offshore the Hawaiian Islands during March to May 2001. During these operational days we conducted 57 dives at depths ranging from 150 m to 3820 m and collected 1198 volcanic and carbonate rock samples; 185 sediment samples using sediment scoops, push-cores and short vibracores; and assorted megafauna. We occupied 32 closely spaced heat flow stations, and collected 167 water filtration samples for radium analysis. We also recorded about 280 hours of digital beta format video of the bottom. Heat flow and in-situ thermal conductivity was measured on the northwest flank of Oahu. The radium samples were collected during all of the dives east of Oahu by filtering about 200 liters of seawater on the ROV using a new pump/filtration system. The dives addressed a range of research topics that can be roughly subdivided into four groups. Volcanologic observations and petrologic sampling of constructional volcanic features were done on eruptive fissures on the Kohala terrace west of Hawaii, cones on Kilauea's Puna Ridge and the west rift of Kahoolawe, rejuvenated stage cones and flat-topped cones offshore Oahu, Kauai, and Niihau, and postshield stage cones offshore Niihau. The analyzed lavas from the Puna Ridge are tholeiitic basalts with 4.8-6.4% MgO. The samples from the west rift of Kahoolawe are submarine-erupted, high-SiO2, tholeiitic basalt and tuff. The analyzed rejuvenated and postshield stage lavas and tuffs are alkalic and submarine erupted. The subsidence history of the islands and paleoclimatic history were addressed by sampling old shoreline feature such as drowned coral reefs and drowned beaches. Dives with this objective were done on six terraces on the Kohala terrace, one on East Kohala, four south and southwest of Lanai, one north of Molokai, one south of Oahu, one on the Kaena Ridge, and one northwest of Niihau. We recovered corals from most of these locations and reef limestone from all but the Kaena Ridge dive. We explored the origin of submarine canyons northeast of Oahu, north and south of Molokai and east of Kohala. A related objective was to examine several deep plunge pools that occur at the base of the steep slope below the break-in-slope that marks old shorelines. These topics are covered in other abstracts at this meeting. The structure of the flanks of the volcanoes, mainly associated with the headwalls of giant landslides, was investigated during dives on the south Kona slide, east of Kohala, north of Molokai, west of Oahu on a block in the Waianae landslide, and on the northwest flank of Niihau. The analyzed samples are mostly pillow breccia and hyaloclastite composed of subaerially-erupted tholeiitic basalts, although submarine-erupted lavas occur at the base of the Waianae slide block and the slope of Molokai. Video highlights of the dives and preliminary results will be presented.

Rapid Recovery of Visual Function Associated with Blue Cone Ablation in Zebrafish

PubMed Central

Hagerman, Gordon F.; Noel, Nicole C. L.; Cao, Sylvia Y.; DuVal, Michèle G.; Oel, A. Phillip; Allison, W. Ted

2016-01-01

Hurdles in the treatment of retinal degeneration include managing the functional rewiring of surviving photoreceptors and integration of any newly added cells into the remaining second-order retinal neurons. Zebrafish are the premier genetic model for such questions, and we present two new transgenic lines allowing us to contrast vision loss and recovery following conditional ablation of specific cone types: UV or blue cones. The ablation of each cone type proved to be thorough (killing 80% of cells in each intended cone class), specific, and cell-autonomous. We assessed the loss and recovery of vision in larvae via the optomotor behavioural response (OMR). This visually mediated behaviour decreased to about 5% or 20% of control levels following ablation of UV or blue cones, respectively (P<0.05). We further assessed ocular photoreception by measuring the effects of UV light on body pigmentation, and observed that photoreceptor deficits and recovery occurred (p<0.01) with a timeline coincident to the OMR results. This corroborated and extended previous conclusions that UV cones are required photoreceptors for modulating body pigmentation, addressing assumptions that were unavoidable in previous experiments. Functional vision recovery following UV cone ablation was robust, as measured by both assays, returning to control levels within four days. In contrast, robust functional recovery following blue cone ablation was unexpectedly rapid, returning to normal levels within 24 hours after ablation. Ablation of cones led to increased proliferation in the retina, though the rapid recovery of vision following blue cone ablation was demonstrated to not be mediated by blue cone regeneration. Thus rapid visual recovery occurs following ablation of some, but not all, cone subtypes, suggesting an opportunity to contrast and dissect the sources and mechanisms of outer retinal recovery during cone photoreceptor death and regeneration. PMID:27893779

Development of Partial Ontogenic Resistance to Powdery Mildew in Hop Cones and Its Management Implications

PubMed Central

Twomey, Megan C.; Wolfenbarger, Sierra N.; Woods, Joanna L.; Gent, David H.

2015-01-01

Knowledge of processes leading to crop damage is central to devising rational approaches to disease management. Multiple experiments established that infection of hop cones by Podosphaera macularis was most severe if inoculation occurred within 15 to 21 days after bloom. This period of infection was associated with the most pronounced reductions in alpha acids, cone color, and accelerated maturation of cones. Susceptibility of cones to powdery mildew decreased progressively after the transition from bloom to cone development, although complete immunity to the disease failed to develop. Maturation of cone tissues was associated with multiple significant affects on the pathogen manifested as reduced germination of conidia, diminished frequency of penetration of bracts, lengthening of the latent period, and decreased sporulation. Cones challenged with P. macularis in juvenile developmental stages also led to greater frequency of colonization by a complex of saprophytic, secondary fungi. Since no developmental stage of cones was immune to powdery mildew, the incidence of powdery mildew continued to increase over time and exceeded 86% by late summer. In field experiments with a moderately susceptible cultivar, the incidence of cones with powdery mildew was statistically similar when fungicide applications were made season-long or targeted only to the juvenile stages of cone development. These studies establish that partial ontogenic resistance develops in hop cones and may influence multiple phases of the infection process and pathogen reproduction. The results further reinforce the concept that the efficacy of a fungicide program may depend largely on timing of a small number of sprays during a relatively brief period of cone development. However in practice, targeting fungicide and other management tactics to periods of enhanced juvenile susceptibility may be complicated by a high degree of asynchrony in cone development and other factors that are situation-dependent. PMID:25811173

Early-Onset, Slow Progression of Cone Photoreceptor Dysfunction and Degeneration in CNG Channel Subunit CNGB3 Deficiency

PubMed Central

Xu, Jianhua; Morris, Lynsie; Fliesler, Steven J.; Sherry, David M.

2011-01-01

Purpose. To investigate the progression of cone dysfunction and degeneration in CNG channel subunit CNGB3 deficiency. Methods. Retinal structure and function in CNGB3−/− and wild-type (WT) mice were evaluated by electroretinography (ERG), lectin cytochemistry, and correlative Western blot analysis of cone-specific proteins. Cone and rod terminal integrity was assessed by electron microscopy and synaptic protein immunohistochemical distribution. Results. Cone ERG amplitudes (photopic b-wave) in CNGB3−/− mice were reduced to approximately 50% of WT levels by postnatal day 15, decreasing further to approximately 30% of WT levels by 1 month and to approximately 20% by 12 months of age. Rod ERG responses (scotopic a-wave) were not affected in CNGB3−/− mice. Average CNGB3−/− cone densities were approximately 80% of WT levels at 1 month and declined slowly thereafter to only approximately 50% of WT levels by 12 months. Expression levels of M-opsin, cone transducin α-subunit, and cone arrestin in CNGB3−/− mice were reduced by 50% to 60% by 1 month and declined to 35% to 45% of WT levels by 9 months. In addition, cone opsin mislocalized to the outer nuclear layer and the outer plexiform layer in the CNGB3−/− retina. Cone and rod synaptic marker expression and terminal ultrastructure were normal in the CNGB3−/− retina. Conclusions. These findings are consistent with an early-onset, slow progression of cone functional defects and cone loss in CNGB3−/− mice, with the cone signaling deficits arising from disrupted phototransduction and cone loss rather than from synaptic defects. PMID:21273547

Foraging performance of two fishes, the threespine stickleback and the Cumaná guppy, under different light backgrounds.

PubMed

Zukoshi, Reo; Savelli, Ilaria; Novales Flamarique, Iñigo

2018-04-01

Many vertebrates have cone photoreceptors that are most sensitive to ultraviolet (UV) light termed UV cones. The ecological functions that these cones contribute to are seldom known though they are suspected of improving foraging and communication in a variety of fishes. In this study, we used several spectral backgrounds to assess the contribution of UV and violet cones, or long wavelength (L) cones, in the foraging performance of juvenile Cumaná guppy, Poecilia reticulata, or marine stickleback, Gasterosteus aculeatus. Regardless of whether the light spectrum contained or not wavelengths below 450 nm (the limiting wavelength for UV cone stimulation), the foraging performance of both species was statistically the same, as judged by the mean distance and angle associated with attacks on prey (Daphnia magna). Our experiments also showed that the foraging performance of sticklebacks when only the double cones (and, almost exclusively, the L cones) were active was similar to that when all cones were functional, demonstrating that the double cone was sufficient for prey detection. This result indicates that foraging potentially relied on an achromatic channel serving prey motion detection, as the two spectral cone types that make up the double cone [maximally sensitive to middle (M) and long (L) wavelengths, respectively] form the input to the achromatic channel in cyprinid fishes and double cones are widely associated with achromatic tasks in other vertebrates including reptiles and birds. Stickleback performance was also substantially better when foraging under a 100% linearly polarized light field than when under an unpolarized light field. Together, our results suggest that in some teleost species UV cones exert visually-mediated ecological functions different from foraging, and furthermore that polarization sensitivity could improve the foraging performance of sticklebacks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cone opsins, colour blindness and cone dystrophy: Genotype-phenotype correlations.

PubMed

Gardner, J C; Michaelides, M; Hardcastle, A J

2016-05-25

X-linked cone photoreceptor disorders caused by mutations in the OPN1LW (L) and OPN1MW (M) cone opsin genes on chromosome Xq28 include a range of conditions from mild stable red-green colour vision deficiencies to severe cone dystrophies causing progressive loss of vision and blindness. Advances in molecular genotyping and functional analyses of causative variants, combined with deep retinal phenotyping, are unravelling genetic mechanisms underlying the variability of cone opsin disorders.

Development of a full ice-cream cone model for halo CME structures

NASA Astrophysics Data System (ADS)

Na, Hyeonock; Moon, Yong-Jae

2015-04-01

The determination of three dimensional parameters (e.g., radial speed, angular width, source location) of Coronal Mass Ejections (CMEs) is very important for space weather forecast. To estimate these parameters, several cone models based on a flat cone or a shallow ice-cream cone with spherical front have been suggested. In this study, we investigate which cone model is proper for halo CME morphology using 33 CMEs which are identified as halo CMEs by one spacecraft (SOHO or STEREO-A or B) and as limb CMEs by the other ones. From geometrical parameters of these CMEs such as their front curvature, we find that near full ice-cream cone CMEs (28 events) are dominant over shallow ice-cream cone CMEs (5 events). So we develop a new full ice-cream cone model by assuming that a full ice-cream cone consists of many flat cones with different heights and angular widths. This model is carried out by the following steps: (1) construct a cone for given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, (4) minimize the difference between the estimated projection points with the observed ones. We apply this model to several halo CMEs and compare the results with those from other methods such as a Graduated Cylindrical Shell model and a geometrical triangulation method.

Loss and gain of cone types in vertebrate ciliary photoreceptor evolution.

PubMed

Musser, Jacob M; Arendt, Detlev

2017-11-01

Ciliary photoreceptors are a diverse cell type family that comprises the rods and cones of the retina and other related cell types such as pineal photoreceptors. Ciliary photoreceptor evolution has been dynamic during vertebrate evolution with numerous gains and losses of opsin and phototransduction genes, and changes in their expression. For example, early mammals lost all but two cone opsins, indicating loss of cone receptor types in response to nocturnal lifestyle. Our review focuses on the comparison of specifying transcription factors and cell type-specific transcriptome data in vertebrate retinae to build and test hypotheses on ciliary photoreceptor evolution. Regarding cones, recent data reveal that a combination of factors specific for long-wavelength sensitive opsin (Lws)- cones in non-mammalian vertebrates (Thrb and Rxrg) is found across all differentiating cone photoreceptors in mice. This suggests that mammalian ancestors lost all but one ancestral cone type, the Lws-cone. We test this hypothesis by a correlation analysis of cone transcriptomes in mouse and chick, and find that, indeed, transcriptomes of all mouse cones are most highly correlated to avian Lws-cones. These findings underscore the importance of specifying transcription factors in tracking cell type evolution, and shed new light on the mechanisms of cell type loss and gain in retina evolution. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Cone and Seed Maturation of Southern Pines

Treesearch

James P. Barnett

1976-01-01

If slightly reduced yields and viability are acceptable, loblolly and slash cone collections can begin 2 to 3 weeks before maturity if the cones are stored before processing. Longleaf(P. palestris Mill.) pine cones should be collected only when mature, as storage decreased germination of seeds from immature cones. Biochemical analyses to determine reducing sugar...

Comparison of the CME-associated shock arrival times at the earth using the WSA-ENLIL model with three cone models

NASA Astrophysics Data System (ADS)

Jang, S.; Moon, Y.; Na, H.

2012-12-01

We have made a comparison of CME-associated shock arrival times at the earth based on the WSA-ENLIL model with three cone models using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters from Michalek et al. (2007) as well as their associated interplanetary (IP) shocks. For this study we consider three different cone models (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine CME cone parameters (radial velocity, angular width and source location), which are used for input parameters of the WSA-ENLIL model. The mean absolute error (MAE) of the arrival times for the elliptical cone model is 10 hours, which is about 2 hours smaller than those of the other models. However, this value is still larger than that (8.7 hours) of an empirical model by Kim et al. (2007). We are investigating several possibilities on relatively large errors of the WSA-ENLIL cone model, which may be caused by CME-CME interaction, background solar wind speed, and/or CME density enhancement.

The Na+/Ca2+, K+ exchanger NCKX4 is required for efficient cone-mediated vision

PubMed Central

Vinberg, Frans; Wang, Tian; De Maria, Alicia; Zhao, Haiqing; Bassnett, Steven; Chen, Jeannie; Kefalov, Vladimir J

2017-01-01

Calcium (Ca2+) plays an important role in the function and health of neurons. In vertebrate cone photoreceptors, Ca2+ controls photoresponse sensitivity, kinetics, and light adaptation. Despite the critical role of Ca2+ in supporting the function and survival of cones, the mechanism for its extrusion from cone outer segments is not well understood. Here, we show that the Na+/Ca2+, K+ exchanger NCKX4 is expressed in zebrafish, mouse, and primate cones. Functional analysis of NCKX4-deficient mouse cones revealed that this exchanger is essential for the wide operating range and high temporal resolution of cone-mediated vision. We show that NCKX4 shapes the cone photoresponse together with the cone-specific NCKX2: NCKX4 acts early to limit response amplitude, while NCKX2 acts late to further accelerate response recovery. The regulation of Ca2+ by NCKX4 in cones is a novel mechanism that supports their ability to function as daytime photoreceptors and promotes their survival. DOI: http://dx.doi.org/10.7554/eLife.24550.001 PMID:28650316

Phylogenetic relationships of cone snails endemic to Cabo Verde based on mitochondrial genomes.

PubMed

Abalde, Samuel; Tenorio, Manuel J; Afonso, Carlos M L; Uribe, Juan E; Echeverry, Ana M; Zardoya, Rafael

2017-11-25

Due to their great species and ecological diversity as well as their capacity to produce hundreds of different toxins, cone snails are of interest to evolutionary biologists, pharmacologists and amateur naturalists alike. Taxonomic identification of cone snails still relies mostly on the shape, color, and banding patterns of the shell. However, these phenotypic traits are prone to homoplasy. Therefore, the consistent use of genetic data for species delimitation and phylogenetic inference in this apparently hyperdiverse group is largely wanting. Here, we reconstruct the phylogeny of the cones endemic to Cabo Verde archipelago, a well-known radiation of the group, using mitochondrial (mt) genomes. The reconstructed phylogeny grouped the analyzed species into two main clades, one including Kalloconus from West Africa sister to Trovaoconus from Cabo Verde and the other with a paraphyletic Lautoconus due to the sister group relationship of Africonus from Cabo Verde and Lautoconus ventricosus from Mediterranean Sea and neighboring Atlantic Ocean to the exclusion of Lautoconus endemic to Senegal (plus Lautoconus guanche from Mauritania, Morocco, and Canary Islands). Within Trovaoconus, up to three main lineages could be distinguished. The clade of Africonus included four main lineages (named I to IV), each further subdivided into two monophyletic groups. The reconstructed phylogeny allowed inferring the evolution of the radula in the studied lineages as well as biogeographic patterns. The number of cone species endemic to Cabo Verde was revised under the light of sequence divergence data and the inferred phylogenetic relationships. The sequence divergence between continental members of the genus Kalloconus and island endemics ascribed to the genus Trovaoconus is low, prompting for synonymization of the latter. The genus Lautoconus is paraphyletic. Lautoconus ventricosus is the closest living sister group of genus Africonus. Diversification of Africonus was in allopatry due to the direct development nature of their larvae and mainly triggered by eustatic sea level changes during the Miocene-Pliocene. Our study confirms the diversity of cone endemic to Cabo Verde but significantly reduces the number of valid species. Applying a sequence divergence threshold, the number of valid species within the sampled Africonus is reduced to half.

Rods and cones contain antigenically distinctive S-antigens.

PubMed

Nork, T M; Mangini, N J; Millecchia, L L

1993-09-01

S-antigen (48 kDa protein or arrestin) is known to be present in rod photoreceptors. Its localization in cones is less clear with several conflicting reports among various species examined. This study employed three different anti-S-antigen antibodies (a48K, a polyclonal antiserum and two monoclonal antibodies, MAb A9-C6 and MAb 5c6.47) and examined their localization in rods and cones of human and cat retinas. To identify the respective cone types, an enzyme histochemical technique for carbonic anhydrase (CA) was employed to distinguish blue cones (CA-negative) from red or green cones (CA-positive). S-antigen localization was then examined by immunocytochemical staining of adjacent sections. In human retinas, a similar labeling pattern was seen with both a48K and MAb A9-C6, i.e., the rods and blue-sensitive cones were strongly positive, whereas the red- or green-sensitive cones showed little immunoreactivity. All human photoreceptors showed reactivity to MAb 5c6.47. In the cat retina, only CA-positive cones could be found. As in the human retina, both rods and cones of the cat were positive for MAb 5c6.47. A difference from the labeling pattern in human retina was noted for the other S-antigen antibodies; a48K labeled rods and all of the cones, whereas MAb A9-C6 reacted strongly with the rods but showed no cone staining. These results suggest that both rods and cones contain S-antigen but that they are antigenically distinctive.

Directional imaging of the retinal cone mosaic

NASA Astrophysics Data System (ADS)

Vohnsen, Brian; Iglesias, Ignacio; Artal, Pablo

2004-05-01

We describe a near-IR scanning laser ophthalmoscope that allows the retinal cone mosaic to be imaged in the human eye in vivo without the use of wave-front correction techniques. The method takes advantage of the highly directional quality of cone photoreceptors that permits efficient coupling of light to individual cones and subsequent detection of most directional components of the backscattered light produced by the light-guiding effect of the cones. We discuss details of the system and describe cone-mosaic images obtained under different conditions.

Cone-Specific Promoters for Gene Therapy of Achromatopsia and Other Retinal Diseases

PubMed Central

Ye, Guo-Jie; Budzynski, Ewa; Sonnentag, Peter; Nork, T. Michael; Sheibani, Nader; Gurel, Zafer; Boye, Sanford L.; Peterson, James J.; Boye, Shannon E.; Hauswirth, William W.; Chulay, Jeffrey D.

2016-01-01

Adeno-associated viral (AAV) vectors containing cone-specific promoters have rescued cone photoreceptor function in mouse and dog models of achromatopsia, but cone-specific promoters have not been optimized for use in primates. Using AAV vectors administered by subretinal injection, we evaluated a series of promoters based on the human L-opsin promoter, or a chimeric human cone transducin promoter, for their ability to drive gene expression of green fluorescent protein (GFP) in mice and nonhuman primates. Each of these promoters directed high-level GFP expression in mouse photoreceptors. In primates, subretinal injection of an AAV-GFP vector containing a 1.7-kb L-opsin promoter (PR1.7) achieved strong and specific GFP expression in all cone photoreceptors and was more efficient than a vector containing the 2.1-kb L-opsin promoter that was used in AAV vectors that rescued cone function in mouse and dog models of achromatopsia. A chimeric cone transducin promoter that directed strong GFP expression in mouse and dog cone photoreceptors was unable to drive GFP expression in primate cones. An AAV vector expressing a human CNGB3 gene driven by the PR1.7 promoter rescued cone function in the mouse model of achromatopsia. These results have informed the design of an AAV vector for treatment of patients with achromatopsia. PMID:26603570

Cone-Specific Promoters for Gene Therapy of Achromatopsia and Other Retinal Diseases.

PubMed

Ye, Guo-Jie; Budzynski, Ewa; Sonnentag, Peter; Nork, T Michael; Sheibani, Nader; Gurel, Zafer; Boye, Sanford L; Peterson, James J; Boye, Shannon E; Hauswirth, William W; Chulay, Jeffrey D

2016-01-01

Adeno-associated viral (AAV) vectors containing cone-specific promoters have rescued cone photoreceptor function in mouse and dog models of achromatopsia, but cone-specific promoters have not been optimized for use in primates. Using AAV vectors administered by subretinal injection, we evaluated a series of promoters based on the human L-opsin promoter, or a chimeric human cone transducin promoter, for their ability to drive gene expression of green fluorescent protein (GFP) in mice and nonhuman primates. Each of these promoters directed high-level GFP expression in mouse photoreceptors. In primates, subretinal injection of an AAV-GFP vector containing a 1.7-kb L-opsin promoter (PR1.7) achieved strong and specific GFP expression in all cone photoreceptors and was more efficient than a vector containing the 2.1-kb L-opsin promoter that was used in AAV vectors that rescued cone function in mouse and dog models of achromatopsia. A chimeric cone transducin promoter that directed strong GFP expression in mouse and dog cone photoreceptors was unable to drive GFP expression in primate cones. An AAV vector expressing a human CNGB3 gene driven by the PR1.7 promoter rescued cone function in the mouse model of achromatopsia. These results have informed the design of an AAV vector for treatment of patients with achromatopsia.

Scattering of electromagnetic waves from a cone with conformal mapping: Application to scanning near-field optical microscope

NASA Astrophysics Data System (ADS)

Chui, S. T.; Chen, Xinzhong; Liu, Mengkun; Lin, Zhifang; Zi, Jian

2018-02-01

We study the response of a conical metallic surface to an external electromagnetic (em) field by representing the fields in basis functions containing the integrable singularity at the tip of the cone. A fast analytical solution is obtained by the conformal mapping between the cone and a round disk. We apply our calculation to the scattering-type scanning near-field optical microscope (s-SNOM) and successfully quantify the elastic light scattering from a vibrating metallic tip over a uniform sample. We find that the field-induced charge distribution consists of localized terms at the tip and the base and an extended bulk term along the body of the cone far away from the tip. In recent s-SNOM experiments at the visible and infrared range (600 nm to 1 μ m ) the fundamental of the demodulated near-field signal is found to be much larger than the higher harmonics whereas at THz range (100 μ m to 3 mm) the fundamental becomes comparable to the higher harmonics. We find that the localized tip charge dominates the contribution to the higher harmonics and becomes larger for the THz experiments, thus providing an intuitive understanding of the origin of the near-field signals. We demonstrate the application of our method by extracting a two-dimensional effective dielectric constant map from the s-SNOM image of a finite metallic disk, where the variation comes from the charge density induced by the em field.

Assessment of the Airway Characteristics in Children with Cleft Lip and Palate using Cone Beam Computed Tomography

PubMed Central

Marwah, Nikhil

2016-01-01

ABSTRACT Objective: The aim of our study is to use cone beam computed tomography (CBCT) to assess the dimensional changes in the nasopharyngeal soft-tissue characteristics in children of Indian origin with repaired cleft lip and palate (CLP) and to compare the results with patients with ideal occlusion. Materials and methods: A sample of 20 children (10 girls, 10 boys) with repaired CLP was selected. Cone beam computed tomography scans were taken to measure the nasopharyngeal airway changes in terms of linear measurements and sagittal cross-sectional areas. Error analysis was performed to prevent systematic or random errors. Independent means t-tests and Pearson correlation analysis were used to evaluate sex differences and the correlations among the variables. Results: Nasopharyngeal soft-tissue characteristics were different in the control and the study groups. Subjects with repaired CLP had lesser lower aerial width, lower adenoidal width and lower airway width. The upper airway width was also significantly lesser. The retropalatal and the total airway area were significantly greater in the control group. Conclusion: The narrow pharyngeal airway in patients with CLP might result in functional impairment of breathing in patients. Further investigations are necessary to clarify the relationship between pharyngeal structure and airway function in patients with CLP. How to cite this article: Agarwal A, Marwah N. Assessment of the Airway Characteristics in Children with Cleft Lip and Palate using Cone Beam Computed Tomography. Int J Clin Pediatr Dent 2016;9(1):5-9. PMID:27274147

Pinaceae-like reproductive morphology in Schizolepidopsis canicularis sp. nov. from the Early Cretaceous (Aptian-Albian) of Mongolia.

PubMed

Leslie, Andrew B; Glasspool, Ian; Herendeen, Patrick S; Ichinnorov, Niiden; Knopf, Patrick; Takahashi, Masamichi; Crane, Peter R

2013-12-01

Seed cone scales assigned to the genus Schizolepidopsis are widespread in Late Triassic to Cretaceous Eurasian deposits. They have been linked to the conifer family Pinaceae based on associated vegetative remains, but their exact affinities are uncertain. Recently discovered material from the Early Cretaceous of Mongolia reveals important new information concerning Schizolepidopsis cone scales and seeds, and provides support for a relationship between the genus and extant Pinaceae. Specimens were collected from Early Cretaceous (probable Aptian-Albian) lignite deposits in central Mongolia. Lignite samples were disaggregated, cleaned in hydrofluoric acid, and washed in water. Specimens were selected for further study using light and electron microscopy. Schizolepidopsis canicularis seed cones consist of loosely arranged, bilobed ovulate scales subtended by a small bract. A single inverted seed with an elongate micropyle is borne on each lobe of the ovulate scale. Each seed has a wing formed by the separation of the adaxial surface of the ovulate scale. Schizolepidopsis canicularis produced winged seeds that formed in a manner that is unique to Pinaceae among extant conifers. We do not definitively place this species in Pinaceae pending more complete information concerning its pollen cones and vegetative remains. Nevertheless, this material suggests that Schizolepidopsis may be important for understanding the early evolution of Pinaceae, and may potentially help reconcile the appearance of the family in the fossil record with results based on phylogenetic analyses of molecular data.

Geochemical characteristics of the La Réunion mantle plume source inferred from olivine-hosted melt inclusions from the adventive cones of Piton de la Fournaise volcano (La Réunion Island)

NASA Astrophysics Data System (ADS)

Valer, Marina; Schiano, Pierre; Bachèlery, Patrick

2017-09-01

Major and trace element compositions were obtained for bulk rocks and melt inclusions hosted in olivine crystals (Fo > 85) from the adventive cones of the Piton de La Fournaise volcano (La Réunion Island). Ratios of highly incompatible trace elements for these magmas are used to identify the nature of the La Réunion mantle plume source. Although adventive cone lavas display unusual major element compositions compared to the historical lavas of the volcano (e.g., lower CaO/Al2O3), trace element data suggest that the magmas emitted by the adventive cones originate from a common chemical source. This source may correspond to either a homogeneous mixed source of different mantle components or a near-primitive less-differentiated mantle source. The melt inclusions display ratios of highly incompatible elements (e.g., Th/La, Nb/La) which are similar to primitive mantle values, and lower Nb/U ratios compared to most oceanic basalts. These results and previous isotopic and trace element data suggest that La Réunion plume samples a source which is intermediate between a primitive-like mantle domain and a slightly depleted one almost unaffected by the recycling processes. This source could have originated from early depletion of the primitive mantle. Assuming a depletion 4.45 Gyr ago, 10% melting of this slightly depleted source could explain the enriched trace element concentrations of the melt inclusions.

Are seed and cone pathogens causing significant losses in Pacific Northwest seed orchards?

Treesearch

E.E. Nelson; W.G. Thies; C.Y. Li

1986-01-01

Cones systematically collected in 1983 from eight Douglas-fir seed orchards in western Washington and Oregon yielded large numbers of common molds. Fungi isolated from apparently healthy, developing cones were similar to those from necrotic cones. Necrosis in cones aborted in early stages of development was apparently not associated with pathogenic fungi or bacteria....

Automated identification of cone photoreceptors in adaptive optics retinal images.

PubMed

Li, Kaccie Y; Roorda, Austin

2007-05-01

In making noninvasive measurements of the human cone mosaic, the task of labeling each individual cone is unavoidable. Manual labeling is a time-consuming process, setting the motivation for the development of an automated method. An automated algorithm for labeling cones in adaptive optics (AO) retinal images is implemented and tested on real data. The optical fiber properties of cones aided the design of the algorithm. Out of 2153 manually labeled cones from six different images, the automated method correctly identified 94.1% of them. The agreement between the automated and the manual labeling methods varied from 92.7% to 96.2% across the six images. Results between the two methods disagreed for 1.2% to 9.1% of the cones. Voronoi analysis of large montages of AO retinal images confirmed the general hexagonal-packing structure of retinal cones as well as the general cone density variability across portions of the retina. The consistency of our measurements demonstrates the reliability and practicality of having an automated solution to this problem.

Micro-cones on a liquid interface in high electric field: Ionization effects

NASA Astrophysics Data System (ADS)

Subbotin, Andrey V.; Semenov, Alexander N.

2018-02-01

We formulate and explore electrohydrodynamic equations for conductive liquids taking dissociation/recombination processes into account and discover a novel type of liquid cones which carry both surface and net bulk charge and can be formed on a liquid interface in an electric field. The bulk charge is generated by the corona discharge due to a high electric field at the cone apex. We establish correlation between the cone angle and physical parameters of the liquid on the one hand and the electric current passing through the cone on the other hand. It is shown that the current strongly increases when the cone angle tends to a critical value which is a function of the dielectric permittivity of the liquid. The cone stability with respect to axially symmetric perturbations is analyzed. It is shown that the cones with apex angles close to the critical angle are likely to be stable. The effect of the imposed flow on the cone apex stability is also discussed.

Filopodial dynamics and growth cone stabilization in Drosophila visual circuit development

PubMed Central

Özel, Mehmet Neset; Langen, Marion; Hassan, Bassem A; Hiesinger, P Robin

2015-01-01

Filopodial dynamics are thought to control growth cone guidance, but the types and roles of growth cone dynamics underlying neural circuit assembly in a living brain are largely unknown. To address this issue, we have developed long-term, continuous, fast and high-resolution imaging of growth cone dynamics from axon growth to synapse formation in cultured Drosophila brains. Using R7 photoreceptor neurons as a model we show that >90% of the growth cone filopodia exhibit fast, stochastic dynamics that persist despite ongoing stepwise layer formation. Correspondingly, R7 growth cones stabilize early and change their final position by passive dislocation. N-Cadherin controls both fast filopodial dynamics and growth cone stabilization. Surprisingly, loss of N-Cadherin causes no primary targeting defects, but destabilizes R7 growth cones to jump between correct and incorrect layers. Hence, growth cone dynamics can influence wiring specificity without a direct role in target recognition and implement simple rules during circuit assembly. DOI: http://dx.doi.org/10.7554/eLife.10721.001 PMID:26512889

If Lava Mingled with Ground Ice on Mars

NASA Astrophysics Data System (ADS)

Martel, L. M. V.

2001-06-01

Clusters of small cones on the lava plains of Mars have caught the attention of planetary geologists for years for a simple and compelling reason: ground ice. These cones look like volcanic rootless cones found on Earth where hot lava flows over wet surfaces such as marshes, shallow lakes or shallow aquifers. Steam explosions fragment the lava into small pieces that fall into cone-shaped debris piles. Peter Lanagan, Alfred McEwen, Laszlo Keszthelyi (University of Arizona), and Thorvaldur Thordarson (University of Hawaii) recently identified groups of cones in the equatorial region of Mars using new high-resolution Mars Orbiter Camera (MOC) images. They report that the Martian cones have the same appearance, size, and geologic setting as rootless cones found in Iceland. If the Martian and terrestrial cones formed in the same way, then the Martian cones mark places where ground ice or groundwater existed at the time the lavas surged across the surface, estimated to be less than 10 million years ago, and where ground ice may still be today.

Dual energy approach for cone beam artifacts correction

NASA Astrophysics Data System (ADS)

Han, Chulhee; Choi, Shinkook; Lee, Changwoo; Baek, Jongduk

2017-03-01

Cone beam computed tomography systems generate 3D volumetric images, which provide further morphological information compared to radiography and tomosynthesis systems. However, reconstructed images by FDK algorithm contain cone beam artifacts when a cone angle is large. To reduce the cone beam artifacts, two-pass algorithm has been proposed. The two-pass algorithm considers the cone beam artifacts are mainly caused by high density materials, and proposes an effective method to estimate error images (i.e., cone beam artifacts images) by the high density materials. While this approach is simple and effective with a small cone angle (i.e., 5 - 7 degree), the correction performance is degraded as the cone angle increases. In this work, we propose a new method to reduce the cone beam artifacts using a dual energy technique. The basic idea of the proposed method is to estimate the error images generated by the high density materials more reliably. To do this, projection data of the high density materials are extracted from dual energy CT projection data using a material decomposition technique, and then reconstructed by iterative reconstruction using total-variation regularization. The reconstructed high density materials are used to estimate the error images from the original FDK images. The performance of the proposed method is compared with the two-pass algorithm using root mean square errors. The results show that the proposed method reduces the cone beam artifacts more effectively, especially with a large cone angle.

Growth cones are actively influenced by substrate-bound adhesion molecules.

PubMed

Burden-Gulley, S M; Payne, H R; Lemmon, V

1995-06-01

As axons advance to appropriate target tissues during development, their growth cones encounter a variety of cell adhesion molecules (CAMs) and extracellular matrix molecules (ECM molecules). Purified CAMs and ECM molecules influence neurite outgrowth in vitro and are thought to have a similar function in vivo. For example, when retinal ganglion cell (RGC) neurons are grown on different CAM and ECM molecule substrates in vitro, their growth cones display distinctive morphologies (Payne et al., 1992). Similarly, RGC growth cones in vivo have distinctive shapes at different points in the pathway from the eye to the tectum, suggesting the presence of localized cues that determine growth cone behaviors such as pathway selection at choice points. In this report, time-lapse video microscopy was utilized to examine dynamic transformations of RGC growth cones as they progressed from L1/8D9, N-cadherin, or laminin onto a different substrate. Contact made by the leading edge of a growth cone with a new substrate resulted in a rapid and dramatic alteration in growth cone morphology. In some cases, the changes encompassed the entire growth cone including those regions not in direct contact with the new substrate. In addition, the growth cones displayed a variety of behavioral responses that were dependent upon the order of substrate contact. These studies demonstrate that growth cones are actively affected by the substrate, and suggest that abrupt changes in the molecular composition of the growth cone environment are influential during axonal pathfinding.

Identification of a cone bipolar cell in cat retina which has input from both rod and cone photoreceptors.

PubMed

Fyk-Kolodziej, Bozena; Qin, Pu; Pourcho, Roberta G

2003-09-08

It has been generally accepted that rod photoreceptor cells in the mammalian retina make synaptic contact with only a single population of rod bipolar cells, whereas cone photoreceptors contact a variety of cone bipolar cells. This assumption has been challenged in rodents by reports of a type of cone bipolar cell which receives input from both rods and cones. Questions remained as to whether similar pathways are present in other mammals. We have used an antiserum against the glutamate transporter GLT1-B to visualize a population of cone bipolar cells in the cat retina which make flat contacts with axon terminals of both rod and cone photoreceptor cells. These cells are identified as OFF-cone bipolar cells and correspond morphologically to type cb1 (CBa2) cone bipolar cells which are a major source of input to OFF-beta ganglion cells in the cat retina. The GLT1-B transporter was also localized to processes making flat contacts with photoreceptor terminals in rat and rabbit retinas. Examination of tissue processed for the GluR1 glutamate receptor subunit showed that cb1 cone bipolar cells, like their rodent counterparts, express this alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-selective receptor at their contacts with rod spherules. Thus, a direct excitatory pathway from rod photoreceptors to OFF-cone bipolar cells appears to be a common feature of mammalian retinas. Copyright 2003 Wiley-Liss, Inc.

Tubular graphite cones.

PubMed

Zhang, Guangyu; Jiang, Xin; Wang, Enge

2003-04-18

We report the synthesis of tubular graphite cones using a chemical vapor deposition method. The cones have nanometer-sized tips, micrometer-sized roots, and hollow interiors with a diameter ranging from about 2 to several tens of nanometers. The cones are composed of cylindrical graphite sheets; a continuous shortening of the graphite layers from the interior to the exterior makes them cone-shaped. All of the tubular graphite cones have a faceted morphology. The constituent graphite sheets have identical chiralities of a zigzag type across the entire diameter, imparting structural control to tubular-based carbon structures. The tubular graphite cones have potential for use as tips for scanning probe microscopy, but with greater rigidity and easier mounting than currently used carbon nanotubes.

Human Blue Cone Opsin Regeneration Involves Secondary Retinal Binding with Analog Specificity.

PubMed

Srinivasan, Sundaramoorthy; Fernández-Sampedro, Miguel A; Morillo, Margarita; Ramon, Eva; Jiménez-Rosés, Mireia; Cordomí, Arnau; Garriga, Pere

2018-03-27

Human color vision is mediated by the red, green, and blue cone visual pigments. Cone opsins are G-protein-coupled receptors consisting of an opsin apoprotein covalently linked to the 11-cis-retinal chromophore. All visual pigments share a common evolutionary origin, and red and green cone opsins exhibit a higher homology, whereas blue cone opsin shows more resemblance to the dim light receptor rhodopsin. Here we show that chromophore regeneration in photoactivated blue cone opsin exhibits intermediate transient conformations and a secondary retinoid binding event with slower binding kinetics. We also detected a fine-tuning of the conformational change in the photoactivated blue cone opsin binding site that alters the retinal isomer binding specificity. Furthermore, the molecular models of active and inactive blue cone opsins show specific molecular interactions in the retinal binding site that are not present in other opsins. These findings highlight the differential conformational versatility of human cone opsin pigments in the chromophore regeneration process, particularly compared to rhodopsin, and point to relevant functional, unexpected roles other than spectral tuning for the cone visual pigments. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.

A transcriptomics investigation into pine reproductive organ development.

PubMed

Niu, Shihui; Yuan, Huwei; Sun, Xinrui; Porth, Ilga; Li, Yue; El-Kassaby, Yousry A; Li, Wei

2016-02-01

The development of reproductive structures in gymnosperms is still poorly studied because of a lack of genomic information and useful genetic tools. The hermaphroditic reproductive structure derived from unisexual gymnosperms is an even less studied aspect of seed plant evolution. To extend our understanding of the molecular mechanism of hermaphroditism and the determination of sexual identity of conifer reproductive structures in general, unisexual and bisexual cones from Pinus tabuliformis were profiled for gene expression using 60K microarrays. Expression patterns of genes during progression of sexual cone development were analysed using RNA-seq. The results showed that, overall, the transcriptomes of male structures in bisexual cones were more similar to those of female cones. However, the expression of several MADS-box genes in the bisexual cones was similar to that of male cones at the more juvenile developmental stage, while despite these expression shifts, male structures of bisexual cones and normal male cones were histologically indistinguishable and cone development was continuous. This study represents a starting point for in-depth analysis of the molecular regulation of cone development and also the origin of hermaphroditism in pine. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Pioneer Mars 1979 mission options

NASA Technical Reports Server (NTRS)

Friedlander, A. L.; Hartmann, W. K.; Niehoff, J. C.

1974-01-01

A preliminary investigation of lower cost Mars missions which perform useful exploration objectives after the Viking/75 mission was conducted. As a study guideline, it was assumed that significant cost savings would be realized by utilizing Pioneer hardware currently being developed for a pair of 1978 Venus missions. This in turn led to the additional constraint of a 1979 launch with the Atlas/Centaur launch vehicle which has been designated for the Pioneer Venus missions. Two concepts, using an orbiter bus platform, were identified which have both good science potential and mission simplicity indicative of lower cost. These are: (1) an aeronomy/geology orbiter, and (2) a remote sensing orbiter with a number of deployable surface penetrometers.

Comparison of interplanetary CME arrival times and solar wind parameters based on the WSA-ENLIL model with three cone types and observations

NASA Astrophysics Data System (ADS)

Jang, Soojeong; Moon, Y.-J.; Lee, Jae-Ok; Na, Hyeonock

2014-09-01

We have made a comparison between coronal mass ejection (CME)-associated shock propagations based on the Wang-Sheeley-Arge (WSA)-ENLIL model using three cone types and in situ observations. For this we use 28 full-halo CMEs, whose cone parameters are determined and their corresponding interplanetary shocks were observed at the Earth, from 2001 to 2002. We consider three different cone types (an asymmetric cone model, an ice cream cone model, and an elliptical cone model) to determine 3-D CME cone parameters (radial velocity, angular width, and source location), which are the input values of the WSA-ENLIL model. The mean absolute error of the CME-associated shock travel times for the WSA-ENLIL model using the ice-cream cone model is 9.9 h, which is about 1 h smaller than those of the other models. We compare the peak values and profiles of solar wind parameters (speed and density) with in situ observations. We find that the root-mean-square errors of solar wind peak speed and density for the ice cream and asymmetric cone model are about 190 km/s and 24/cm3, respectively. We estimate the cross correlations between the models and observations within the time lag of ± 2 days from the shock travel time. The correlation coefficients between the solar wind speeds from the WSA-ENLIL model using three cone types and in situ observations are approximately 0.7, which is larger than those of solar wind density (cc ˜0.6). Our preliminary investigations show that the ice cream cone model seems to be better than the other cone models in terms of the input parameters of the WSA-ENLIL model.

Distribution of cone density, spacing and arrangement in adult healthy retinas with adaptive optics flood illumination

PubMed Central

Gaudric, Alain; Woog, Kelly

2018-01-01

The aim of this article is to analyse cone density, spacing and arrangement using an adaptive optics flood illumination retina camera (rtx1™) on a healthy population. Cone density, cone spacing and packing arrangements were measured on the right retinas of 109 subjects at 2°, 3°, 4°, 5° and 6° of eccentricity along 4 meridians. The effects of eccentricity, meridian, axial length, spherical equivalent, gender and age were evaluated. Cone density decreased on average from 28 884 ± 3 692 cones/mm2, at 2° of eccentricity, to 15 843 ± 1 598 cones/mm2 at 6°. A strong inter-individual variation, especially at 2°, was observed. No important difference of cone density was observed between the nasal and temporal meridians or between the superior and inferior meridians. However, the horizontal and vertical meridians differed by around 14% (T-test, p<0.0001). Cone density, expressed in units of area, decreased as a function of axial length (r2 = 0.60), but remained constant (r2 = 0.05) when cone density is expressed in terms of visual angle supporting the hypothesis that the retina is stretched during the elongation of the eyeball. Gender did not modify the cone distribution. Cone density was slightly modified by age but only at 2°. The older group showed a smaller density (7%). Cone spacing increased from 6,49 ± 0,42 μm to 8,72 ± 0,45 μm respectively between 2° and 6° of eccentricity. The mosaic of the retina is mainly triangularly arranged (i.e. cells with 5 to 7 neighbors) from 2° to 6°. Around half of the cells had 6 neighbors. PMID:29338027

The effects of longitudinal chromatic aberration and a shift in the peak of the middle-wavelength sensitive cone fundamental on cone contrast

PubMed Central

Rucker, F. J.; Osorio, D.

2009-01-01

Longitudinal chromatic aberration is a well-known imperfection of visual optics, but the consequences in natural conditions, and for the evolution of receptor spectral sensitivities are less well understood. This paper examines how chromatic aberration affects image quality in the middle-wavelength sensitive (M-) cones, viewing broad-band spectra, over a range of spatial frequencies and focal planes. We also model the effects on M-cone contrast of moving the M-cone fundamental relative to the long- and middle-wavelength (L- and M-cone) fundamentals, while the eye is accommodated at different focal planes or at a focal plane that maximizes luminance contrast. When the focal plane shifts towards longer (650 nm) or shorter wavelengths (420 nm) the effects on M-cone contrast are large: longitudinal chromatic aberration causes total loss of M-cone contrast above 10 to 20 c/d. In comparison, the shift of the M-cone fundamental causes smaller effects on M-cone contrast. At 10 c/d a shift in the peak of the M-cone spectrum from 560 nm to 460 nm decreases M-cone contrast by 30%, while a 10 nm blue-shift causes only a minor loss of contrast. However, a noticeable loss of contrast may be seen if the eye is focused at focal planes other than that which maximizes luminance contrast. The presence of separate long- and middle-wavelength sensitive cones therefore has a small, but not insignificant cost to the retinal image via longitudinal chromatic aberration. This aberration may therefore be a factor limiting evolution of visual pigments and trichromatic color vision. PMID:18639571

Phosphorylation-independent Suppression of Light-activated Visual Pigment by Arrestin in Carp Rods and Cones*

PubMed Central

Tomizuka, Junko; Tachibanaki, Shuji; Kawamura, Satoru

2015-01-01

Visual pigment in photoreceptors is activated by light. Activated visual pigment (R*) is believed to be inactivated by phosphorylation of R* with subsequent binding of arrestin. There are two types of photoreceptors, rods and cones, in the vertebrate retina, and they express different subtypes of arrestin, rod and cone type. To understand the difference in the function between rod- and cone-type arrestin, we first identified the subtype of arrestins expressed in rods and cones in carp retina. We found that two rod-type arrestins, rArr1 and rArr2, are co-expressed in a rod and that a cone-type arrestin, cArr1, is expressed in blue- and UV-sensitive cones; the other cone-type arrestin, cArr2, is expressed in red- and green-sensitive cones. We quantified each arrestin subtype and estimated its concentration in the outer segment of a rod or a cone in the dark; they were ∼0.25 mm (rArr1 plus rArr2) in a rod and 0.6–0.8 mm (cArr1 or cArr2) in a cone. The effect of each arrestin was examined. In contrast to previous studies, both rod and cone arrestins suppressed the activation of transducin in the absence of visual pigment phosphorylation, and all of the arrestins examined (rArr1, rArr2, and cArr2) bound transiently to most probably nonphosphorylated R*. One rod arrestin, rArr2, bound firmly to phosphorylated pigment, and the other two, rArr1 and cArr2, once bound to phosphorylated R* but dissociated from it during incubation. Our results suggested a novel mechanism of arrestin effect on the suppression of the R* activity in both rods and cones. PMID:25713141

Record of complex scoria cone eruptive activity at Red Mountain, Arizona, USA, and implications for monogenetic mafic volcanoes

NASA Astrophysics Data System (ADS)

Riggs, N. R.; Duffield, W. A.

2008-12-01

Scoria cone eruptions are generally modeled as a simple succession from explosive eruption to form the cone to passive effusion of lava, generally from the base of the cone. Sector collapse of scoria cones, wherein parts of the cone are rafted on a lava flow, is increasingly recognized as common, but the reasons that a cone may not be rebuilt are poorly understood. Red Mountain volcano is a Pleistocene scoria cone in the San Francisco Volcanic Field of northern Arizona, USA. The cone lies along the trace of a major steeply dipping normal fault that originated during Proterozoic tectonism and was reactivated in Tertiary time. The earliest phase of eruption at Red Mountain was typical "Strombolian", forming a cone that was followed by or possibly synchronous with lava effusion, toward the west from the base of the cone. Rafting then ensued as the west side of the cone collapsed; approximately 15% of the cone is preserved in mounds as much as 30 m high. Rafting was extensive enough to remove most of the cone over the vent area, which effectively reduced the pressure cap on the magma conduit. Resultant low fountaining fed clastogenic lava flows and minor scoria fallback. Clastogenic flows traveled as far as 4 km and now form a cliff 30-40 m high at the edge of the lava platform. Although several possibilities explain the change in vent dynamics and eruptive style, we favor the interpretation that an increase in magma-rise rate caused collapse of the cone. The abrupt removal of 300 m of material over the vent removed a conduit "cork" and low fountaining began. Magma that had erupted effusively suddenly became explosive. This aspect of scoria cone rafting at Red Mountain is broadly similar to sector collapse followed by explosive eruption in larger systems. A steep-walled, 150-m-high amphitheatre on the northeast side of Red Mountain exposes weakly to strongly altered scoria cemented by calcite, iron, and zeolites. We suggest that vapor-phase alteration was responsible for sealing fine-grained ash beds in the cone, and a pressurized system developed. Residual heat from a dike that was emplaced as part of the magmatic activity provided heat that drove groundwater along the regional fault up into the cone. Eventually the overpressurized system exploded in a phreatic eruption that created the amphitheatre, which has subsequently been enlarged by water and wind erosion. The combined sequence of events at Red Mountain illustrates some of the complexities in monogenetic scoria cone eruptions that have received little attention to date.

Diagnosis of Normal and Abnormal Color Vision with Cone-Specific VEPs.

PubMed

Rabin, Jeff C; Kryder, Andrew C; Lam, Dan

2016-05-01

Normal color vision depends on normal long wavelength (L), middle wavelength (M), and short wavelength sensitive (S) cones. Hereditary "red-green" color vision deficiency (CVD) is due to a shift in peak sensitivity or lack of L or M cones. Hereditary S cone CVD is rare but can be acquired as an early sign of disease. Current tests detect CVD but few diagnose type or severity, critical for linking performance to real-world demands. The anomaloscope and newer subjective tests quantify CVD but are not applicable to infants or cognitively impaired patients. Our purpose was to develop an objective test of CVD with sensitivity and specificity comparable to current tests. A calibrated visual-evoked potential (VEP) display and Food and Drug Administration-approved system was used to record L, M, and S cone-specific pattern-onset VEPs from 18 color vision normals (CVNs) and 13 hereditary CVDs. VEP amplitudes and latencies were compared between groups to establish VEP sensitivity and specificity. Cone VEPs show 100% sensitivity for diagnosis of CVD and 94% specificity for confirming CVN. L cone (protan) CVDs showed a significant increase in L cone latency (53.1 msec, P < 0.003) and decreased amplitude (10.8 uV, P < 0.0000005) but normal M and S cone VEPs ( P > 0.31). M cone (deutan) CVDs showed a significant increase in M cone latency (31.0 msec, P < 0.000004) and decreased amplitude (8.4 uV, P < 0.006) but normal L and S cone VEPs ( P > 0.29). Cone-specific VEPs offer a rapid, objective test to diagnose hereditary CVD and show potential for detecting acquired CVD in various diseases. This paper describes the efficacy of cone-specific color VEPs for quantification of normal and abnormal color vision. The rapid, objective nature of this approach makes it suitable for detecting color sensitivity loss in infants and the cognitively impaired.

New insights on lithofacies architecture, sedimentological characteristics and volcanological evolution of pre-caldera (> 22 ka), multi-phase, scoria- and spatter-cones at Somma-Vesuvius

NASA Astrophysics Data System (ADS)

Sparice, Domenico; Scarpati, Claudio; Perrotta, Annamaria; Mazzeo, Fabio Carmine; Calvert, Andrew T.; Lanphere, Marvin A.

2017-11-01

Pre-caldera (> 22 ka) lateral activity at Somma-Vesuvius is related to scoria- and spatter-cone forming events of monogenetic or polygenetic nature. A new stratigraphic, sedimentological, textural and lithofacies investigation was performed on five parasitic cones (Pollena cones, Traianello cone, S. Maria a Castello cone and the recently found Terzigno cone) occurring below the Pomici di Base (22 ka) Plinian products emplaced during the first caldera collapse at Somma-Vesuvius. A new Ar/Ar age of 23.6 ± 0.3 ka obtained for the Traianello cone as well as the absence of a paleosol or reworked material between the S. Maria a Castello cone and the Pomici di Base deposits suggest that such cone-forming eruptions occurred near the upper limit of the pre-caldera period (22-39 ky). The stratigraphy of three of these eccentric cones (Pollena cones and Traianello cone) exhibits erosion surfaces, exotic tephras, volcaniclastic layers, paleosols, unconformity and paraconformity between superimposed eruptive units revealing their multi-phase, polygenetic evolution related to activation of separate vents and periods of quiescence. Such eccentric cones have been described as composed of scoria deposits and pure effusive lavas by previous authors. Lavas are here re-interpreted as welded horizons (lava-like) composed of coalesced spatter fragments whose pyroclastic nature is locally revealed by relicts of original fragments and remnants of clast outlines. These welded horizons show, locally, rheomorphic structures allowing to define them as emplaced as clastogenic lava flows. The lava-like facies is transitional, upward and downward, to less welded facies composed of agglutinated to unwelded spatter horizons in which clasts outlines are increasingly discernible. Such textural characteristics and facies variation are consistent with a continuous fall deposition of Hawaiian fire-fountains episodes alternated with Strombolian phases emplacing loose scoria deposits. High enrichment factor values, measured in the scoria deposits, imply the ejection of large proportion of ash even during Strombolian events.

Maintenance costs of serotiny in a variably serotinous pine: The role of water supply.

PubMed

Martín-Sanz, Ruth C; Callejas-Díaz, Marta; Tonnabel, Jeanne; Climent, José M

2017-01-01

Serotiny is an important adaptation for plants in fire-prone environments. However, different mechanisms also induce the opening of serotinous cones in the absence of fire in variably serotinous species. Xeriscence -cone opening driven by dry and hot conditions- is considered to be mediated only by the external environment, but endogenous factors could also play a significant role. Using the variably serotinous Pinus halepensis as our model species, we determined the effects of cone age and scales density in cone opening, and using in-situ and ex-situ manipulative experiments we investigated the role of water availability in the opening of serotinous cones. We hypothesized that loss of connection between the cones and the branch through the peduncles or the absence of water supply could induce a faster cone opening. Results showed that older cones lost more water and opened at lower temperatures, with no influence of scales density. Both field and chamber manipulative experiments (using paired cones of the same whorl) confirmed that water intake through the peduncles affected significantly the pace of cone opening, such that lack of water supply speeded up cone dehiscence. However, this was true for weakly serotinous provenances-more common in this species-, while highly serotinous provenances were indifferent to this effect in the field test. All our results support that cone serotiny in P. halepensis involves the allocation of water to the cones, which is highly consistent with the previously observed environmental effects. Importantly, the existence of maintenance costs of serotinous cones has strong implications on the effects of climate change in the resilience of natural populations, via modifications of the canopy seed banks and recruitment after stand-replacing fires. Moreover, evolutionary models for serotiny in P. halepensis must take into account the significant contribution of maintenance costs to the complex interaction between genotype and the environment.

Cone Photoreceptor Packing Density and the Outer Nuclear Layer Thickness in Healthy Subjects

PubMed Central

Chui, Toco Y. P.; Song, Hongxin; Clark, Christopher A.; Papay, Joel A.; Burns, Stephen A.; Elsner, Ann E.

2012-01-01

Purpose. We evaluated the relationship between cone photoreceptor packing density and outer nuclear layer (ONL) thickness within the central 15 degrees. Methods. Individual differences for healthy subjects in cone packing density and ONL thickness were examined in 8 younger and 8 older subjects, mean age 27.2 versus 56.2 years. Cone packing density was obtained using an adaptive optics scanning laser ophthalmoscope (AOSLO). The ONL thickness measurements included the ONL and the Henle fiber layer (ONL + HFL), and were obtained using spectral domain optical coherence tomography (SDOCT) and custom segmentation software. Results. There were sizeable individual differences in cone packing density and ONL + HFL thickness. Older subjects had on average lower cone packing densities, but thicker ONL + HFL measurements. Cone packing density and ONL + HFL thickness decreased with increasing retinal eccentricity. The ratio of the cone packing density-to-ONL2 was larger for the younger subjects group, and decreased with retinal eccentricity. Conclusions. The individual differences in cone packing density and ONL + HFL thickness are consistent with aging changes, indicating that normative aging data are necessary for fine comparisons in the early stages of disease or response to treatment. Our finding of ONL + HFL thickness increasing with aging is inconsistent with the hypothesis that ONL measurements with SDOCT depend only on the number of functioning cones, since in our older group cones were fewer, but thickness was greater. PMID:22570340

Comparison of Asymmetric and Ice-cream Cone Models for Halo Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Na, H.; Moon, Y.

2011-12-01

Halo coronal mass ejections (HCMEs) are major cause of the geomagnetic storms. To minimize the projection effect by coronagraph observation, several cone models have been suggested: an ice-cream cone model, an asymmetric cone model etc. These models allow us to determine the three dimensional parameters of HCMEs such as radial speed, angular width, and the angle between sky plane and central axis of the cone. In this study, we compare these parameters obtained from different models using 48 well-observed HCMEs from 2001 to 2002. And we obtain the root mean square error (RMS error) between measured projection speeds and calculated projection speeds for both cone models. As a result, we find that the radial speeds obtained from the models are well correlated with each other (R = 0.86), and the correlation coefficient of angular width is 0.6. The correlation coefficient of the angle between sky plane and central axis of the cone is 0.31, which is much smaller than expected. The reason may be due to the fact that the source locations of the asymmetric cone model are distributed near the center, while those of the ice-cream cone model are located in a wide range. The average RMS error of the asymmetric cone model (85.6km/s) is slightly smaller than that of the ice-cream cone model (87.8km/s).

Volcanic cones in Hydraotes chaos : implications for the chaotic terrains formation

NASA Astrophysics Data System (ADS)

Meresse, S.; Costard, F.; Mangold, N.; Masson, P.; Neukum, G.

2006-12-01

Numerous geologic scenarios have been proposed for the chaotic terrains formation. They include (1) sub-ice volcanism and other magma-ice interactions and (2) catastrophic release of groundwater from confined aquifers. The lack of volcanic morphology in the chaos was an handicap for the hypothesis of magma-ice interactions but the HRSC (High Resolution Stereo Camera) images have recently revealed possible volcanic cones inside the Hydraotes chaos. About thirty cones lie on the lowest parts of the chaos at elevation between -4300 and -5100 meters. They have basal diameters of 500-1900 m and heights exceeding 100 m. They are observed on young surface: the south smooth floor and inside the narrow valleys separating the mesas. The cones are relatively fresh. Similar morphologies of small cone-shaped structures have been previously identified in the northern lowlands of Mars (Chryse, Acidalia, Amazonis, Isidis and Elysuim Planitia) but their origin remains uncertain. A number of volcanic or cold climate landforms were proposed as potential terrestrial analogues : Icelandic pseudocraters (or rootless cones), cinder cones, tuff cones, pingos and spatter cones. The morphologic measurements made on the Hydraotes cones argue rather for a volcanic origin in comparison with terrestrial analogues. These first volcanic cones observed in Hydraotes chaos suggest that volcanic or subvolcanic activity might have played an important part in the chaotic terrains formation and outflow channels genesis.

Necrotic enlargement of cone photoreceptor cells and the release of high-mobility group box-1 in retinitis pigmentosa

PubMed Central

Murakami, Y; Ikeda, Y; Nakatake, S; Tachibana, T; Fujiwara, K; Yoshida, N; Notomi, S; Nakao, S; Hisatomi, T; Miller, J W; Vavvas, DG; Sonoda, KH; Ishibashi, T

2015-01-01

Retinitis pigmentosa (RP) refers to a group of inherited retinal degenerations resulting form rod and cone photoreceptor cell death. The rod cell death due to deleterious genetic mutations has been shown to occur mainly through apoptosis, whereas the mechanisms and features of the secondary cone cell death have not been fully elucidated. Our previous study showed that the cone cell death in rd10 mice, an animal model of RP, involves necrotic features and is partly mediated by the receptor interacting protein kinase. However, the relevancy of necrotic cone cell death in human RP patients remains unknown. In the present study, we showed that dying cone cells in rd10 mice exhibited cellular enlargement, along with necrotic changes such as cellular swelling and mitochondrial rupture. In human eyes, live imaging of cone cells by adaptive optics scanning laser ophthalmoscopy revealed significantly increased percentages of enlarged cone cells in the RP patients compared with the control subjects. The vitreous of the RP patients contained significantly higher levels of high-mobility group box-1, which is released extracellularly associated with necrotic cell death. These findings suggest that necrotic enlargement of cone cells is involved in the process of cone degeneration, and that necrosis may be a novel target to prevent or delay the loss of cone-mediated central vision in RP. PMID:27551484

Design and development of new collimator cones for fractionated stereotactic radiation therapy in Samsung Medical Center.

PubMed

Ahn, Y C; Ju, S G; Kim, D Y; Choi, D R; Huh, S J; Park, Y H; Lim, D H; Kim, M K

1999-05-01

In stereotactic radiotherapy using X-Knife system, the commercially supplied collimator cone system had a few mechanical limitations. The authors have developed new collimator cones to overcome these limitations and named them "SMC type" collimator cones. We made use of cadmium-free cerrobend alloy within the stainless steel cylinder housing. We made nine cones of relatively larger sizes (3.0 cm to 7.0 cm in diameter) and of shorter length with bigger clearance from the isocenter than the commercial cones. The cone housing and the collimator cones were designed to insert into the wedge mount of the gantry head to enable double-exposure linac-gram taking. The mechanical accuracy of pointing to the isocenter was tested by ball test and cone rotation test, and the dosimetric measurements were performed, all of which were with satisfactory results. A new innovative quality assurance procedure using linac-grams on the patients at the actual treatment setup was attempted after taking 10 sets of AP and lateral linac-grams and the overall mechanical isocenter accuracy was excellent (average error = 0.4 +/- 0.2 mm). We have developed the SMC type collimator cone system mainly for fractionated stereotactic radiation therapy use with our innovative ideas. The new cones' mechanical accuracy and physical properties were satisfactory for clinical use, and the verification of the isocenter accuracy on the actual treatment setup has become possible.

An assessment of the accuracy of stable Fe isotope ratio measurements on samples with organic and inorganic matrices by high-resolution multicollector ICP-MS

NASA Astrophysics Data System (ADS)

Schoenberg, Ronny; von Blanckenburg, Friedhelm

2005-04-01

Multicollector ICP-MS-based stable isotope procedures provide the capability to determine small variations in metal isotope composition of materials, but they are prone to substantial bias introduced by inadequate sample preparation. Such a "cryptic" bias is not necessarily identifiable from the measured isotope ratios. The analytical protocol for Fe isotope analyses of organic and inorganic materials described here identifies and avoids such pitfalls. In medium-mass resolution mode of the ThermoFinnigan Neptune MC-ICP-MS, a 1-ppm Fe solution with an uptake rate of 50-70 [mu]L min-1 yielded 3 × 10-11 A on 56Fe for the ThermoFinnigan stable introduction system and 1.2-1.8 × 10-10 A for the ESI Apex-Q uptake system. Sensitivity was increased again 3-5-fold when using Finnigan X-cones instead of the standard H-cones. The combination of the ESI Apex-Q apparatus and X-cones allowed the determination of the isotope composition on as little as 50 ng of Fe. Fe isotope compositions were corrected for mass bias with both the standard-sample bracketing (SSB) method, and by using the 65Cu/63Cu ratio of added synthetic copper (Cu-doping) as internal monitor of mass discrimination. Both methods provide identical results on high-purity Fe solutions of either synthetic or natural samples. We prefer the SSB method because of its shorter analysis time and more straightforward correction of instrumental mass bias compared to Cu-doping. Strong error correlations of the data are observed in three isotope diagrams. Thus, we suggest that the quality assessment in such diagrams should be performed with error ellipses rather than error bars. Reproducibility of [delta]56Fe, [delta]57Fe and [delta]58Fe values of natural samples alone is not a sufficient criterion for accuracy. A set of tests is lined out that identify cryptic matrix effects and ensure a reproducible level of quality control. Using these criteria and the SSB correction method, we determined the external reproducibilities for [delta]56Fe, [delta]57Fe and [delta]58Fe at the 95% confidence interval from 318 measurements of 95 natural samples to be 0.049, 0.071 and 0.28[per mille sign], respectively.

Cone Storage and Seed Quality in Longleaf Pine

Treesearch

F.T. Bonner

1987-01-01

Immature cones of longleaf pine (Pinus palustris Mill.) can be stored for at least 5 weeks without adversely affecting extraction or seed quality. Cone moisture should be below 50 percent before using heat to open cones.

Deletion of the X-linked opsin gene array locus control region (LCR) results in disruption of the cone mosaic.

PubMed

Carroll, Joseph; Rossi, Ethan A; Porter, Jason; Neitz, Jay; Roorda, Austin; Williams, David R; Neitz, Maureen

2010-09-15

Blue cone monochromacy (BCM) is an X-linked condition in which long- (L) and middle- (M) wavelength-sensitive cone function is absent. Due to the X-linked nature of the condition, female carriers are spared from a full manifestation of the associated defects but can show visual symptoms, including abnormal cone electroretinograms. Here we imaged the cone mosaic in four females carrying an L/M array with deletion of the locus control region, resulting in an absence of L/M opsin gene expression (effectively acting as a cone opsin knockout). On average, they had cone mosaics with reduced density and disrupted organization compared to normal trichromats. This suggests that the absence of opsin in a subset of cones results in their early degeneration, with X-inactivation the likely mechanism underlying phenotypic variability in BCM carriers. Copyright 2010 Elsevier Ltd. All rights reserved.

Long-term changes in flowering and cone production by longleaf pine

Treesearch

William D. Boyer

1998-01-01

Abstract.Cone production by longleaf pine has been followed for up to 30 years in regeneration areas at five to nine coastal plain sites from North Carolina to Louisiana. A rapid increase in the size and frequency of cone crops has occured since 1986 following 20 years of relative stability. Cone production for the last 10 years averaged 36 cones per...

Comparison of the WSA-ENLIL model with three CME cone types

NASA Astrophysics Data System (ADS)

Jang, Soojeong; Moon, Y.; Na, H.

2013-07-01

We have made a comparison of the CME-associated shock propagation based on the WSA-ENLIL model with three cone types using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters as well as their associated interplanetary (IP) shocks. For this study we consider three different cone types (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine 3-D CME parameters (radial velocity, angular width and source location), which are the input values of the WSA-ENLIL model. The mean absolute error (MAE) of the arrival times for the asymmetric cone model is 10.6 hours, which is about 1 hour smaller than those of the other models. Their ensemble average of MAE is 9.5 hours. However, this value is still larger than that (8.7 hours) of the empirical model of Kim et al. (2007). We will compare their IP shock velocities and densities with those from ACE in-situ measurements and discuss them in terms of the prediction of geomagnetic storms.Abstract (2,250 Maximum Characters): We have made a comparison of the CME-associated shock propagation based on the WSA-ENLIL model with three cone types using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters as well as their associated interplanetary (IP) shocks. For this study we consider three different cone types (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine 3-D CME parameters (radial velocity, angular width and source location), which are the input values of the WSA-ENLIL model. The mean absolute error (MAE) of the arrival times for the asymmetric cone model is 10.6 hours, which is about 1 hour smaller than those of the other models. Their ensemble average of MAE is 9.5 hours. However, this value is still larger than that (8.7 hours) of the empirical model of Kim et al. (2007). We will compare their IP shock velocities and densities with those from ACE in-situ measurements and discuss them in terms of the prediction of geomagnetic storms.

℮-conome: an automated tissue counting platform of cone photoreceptors for rodent models of retinitis pigmentosa.

PubMed

Clérin, Emmanuelle; Wicker, Nicolas; Mohand-Saïd, Saddek; Poch, Olivier; Sahel, José-Alain; Léveillard, Thierry

2011-12-20

Retinitis pigmentosa is characterized by the sequential loss of rod and cone photoreceptors. The preservation of cones would prevent blindness due to their essential role in human vision. Rod-derived Cone Viability Factor is a thioredoxin-like protein that is secreted by rods and is involved in cone survival. To validate the activity of Rod-derived Cone Viability Factors (RdCVFs) as therapeutic agents for treating retinitis Pigmentosa, we have developed e-conome, an automated cell counting platform for retinal flat mounts of rodent models of cone degeneration. This automated quantification method allows for faster data analysis thereby accelerating translational research. An inverted fluorescent microscope, motorized and coupled to a CCD camera records images of cones labeled with fluorescent peanut agglutinin lectin on flat-mounted retinas. In an average of 300 fields per retina, nine Z-planes at magnification X40 are acquired after two-stage autofocus individually for each field. The projection of the stack of 9 images is subject to a threshold, filtered to exclude aberrant images based on preset variables. The cones are identified by treating the resulting image using 13 variables empirically determined. The cone density is calculated over the 300 fields. The method was validated by comparison to the conventional stereological counting. The decrease in cone density in rd1 mouse was found to be equivalent to the decrease determined by stereological counting. We also studied the spatiotemporal pattern of the degeneration of cones in the rd1 mouse and show that while the reduction in cone density starts in the central part of the retina, cone degeneration progresses at the same speed over the whole retinal surface. We finally show that for mice with an inactivation of the Nucleoredoxin-like genes Nxnl1 or Nxnl2 encoding RdCVFs, the loss of cones is more pronounced in the ventral retina. The automated platform ℮-conome used here for retinal disease is a tool that can broadly accelerate translational research for neurodegenerative diseases.

Variation of Cone Photoreceptor Packing Density with Retinal Eccentricity and Age

PubMed Central

Song, Hongxin; Chui, Toco Yuen Ping; Zhong, Zhangyi; Elsner, Ann E.

2011-01-01

Purpose. To study the variation of cone photoreceptor packing density across the retina in healthy subjects of different ages. Methods. High-resolution adaptive optics scanning laser ophthalmoscope (AOSLO) systems were used to systematically image the retinas of two groups of subjects of different ages. Ten younger subjects (age range, 22–35 years) and 10 older subjects (age range, 50–65 years) were tested. Strips of cone photoreceptors, approximately 12° × 1.8° long were imaged for each of the four primary retinal meridians: superior, inferior, nasal, and temporal. Cone photoreceptors within the strips were counted, and cone photoreceptor packing density was calculated. Statistical analysis (three-way ANOVA) was used to calculate the interaction for cone photoreceptor packing density between age, meridian, and eccentricity. Results. As expected, cone photoreceptor packing density was higher close to the fovea and decreased with increasing retinal eccentricity from 0.18 to 3.5 mm (∼0.6–12°). Older subjects had approximately 75% of the cone density at 0.18 mm (∼0.6°), and this difference decreased rapidly with eccentricity, with the two groups having similar cone photoreceptor packing densities beyond 0.5 mm retinal eccentricity on average. Conclusions. Cone packing density in the living human retina decreases as a function of age within the foveal center with the largest difference being found at our most central measurement site. At all ages, the retina showed meridional difference in cone densities, with cone photoreceptor packing density decreasing faster with increasing eccentricity in the vertical dimensions than in the horizontal dimensions. PMID:21724911

Variation of cone photoreceptor packing density with retinal eccentricity and age.

PubMed

Song, Hongxin; Chui, Toco Yuen Ping; Zhong, Zhangyi; Elsner, Ann E; Burns, Stephen A

2011-09-01

To study the variation of cone photoreceptor packing density across the retina in healthy subjects of different ages. High-resolution adaptive optics scanning laser ophthalmoscope (AOSLO) systems were used to systematically image the retinas of two groups of subjects of different ages. Ten younger subjects (age range, 22-35 years) and 10 older subjects (age range, 50-65 years) were tested. Strips of cone photoreceptors, approximately 12° × 1.8° long were imaged for each of the four primary retinal meridians: superior, inferior, nasal, and temporal. Cone photoreceptors within the strips were counted, and cone photoreceptor packing density was calculated. Statistical analysis (three-way ANOVA) was used to calculate the interaction for cone photoreceptor packing density between age, meridian, and eccentricity. As expected, cone photoreceptor packing density was higher close to the fovea and decreased with increasing retinal eccentricity from 0.18 to 3.5 mm (∼0.6-12°). Older subjects had approximately 75% of the cone density at 0.18 mm (∼0.6°), and this difference decreased rapidly with eccentricity, with the two groups having similar cone photoreceptor packing densities beyond 0.5 mm retinal eccentricity on average. Cone packing density in the living human retina decreases as a function of age within the foveal center with the largest difference being found at our most central measurement site. At all ages, the retina showed meridional difference in cone densities, with cone photoreceptor packing density decreasing faster with increasing eccentricity in the vertical dimensions than in the horizontal dimensions.

Branching habit and the allocation of reproductive resources in conifers.

PubMed

Leslie, Andrew B

2012-09-01

Correlated relationships between branch thickness, branch density, and twig and leaf size have been used extensively to study the evolution of plant canopy architecture, but fewer studies have explored the impact of these relationships on the allocation of reproductive resources. This study quantifies pollen cone production in conifers, which have similar basic reproductive biology but vary dramatically in branching habit, in order to test how differences in branch diameter influence pollen cone size and the density with which they are deployed in the canopy. Measurements of canopy branch density, the number of cones per branch and cone size were used to estimate the amount of pollen cone tissues produced by 16 species in three major conifer clades. The number of pollen grains produced was also estimated using direct counts from individual pollen cones. The total amount of pollen cone tissues in the conifer canopy varied little among species and clades, although vegetative traits such as branch thickness, branch density and pollen cone size varied over several orders of magnitude. However, branching habit controls the way these tissues are deployed: taxa with small branches produce small pollen cones at a high density, while taxa with large branches produce large cones relatively sparsely. Conifers appear to invest similar amounts of energy in pollen production independent of branching habit. However, similar associations between branch thickness, branch density and pollen cone size are seen across conifers, including members of living and extinct groups not directly studied here. This suggests that reproductive features relating to pollen cone size are in large part a function of the evolution of vegetative morphology and branching habit.

Experimental and raytrace results for throat-to-throat compound parabolic concentrators

NASA Technical Reports Server (NTRS)

Leviton, D. B.; Leitch, J. W.

1986-01-01

Compound parabolic concentrators are nonimaging cone-shaped optics with useful angular transmission characteristics. Two cones used throat-to-throat accept radiant flux within one well-defined acceptance angle and redistribute it into another. If the entrance cone is fed with Lambertian flux, the exit cone produces a beam whose half-angle is the exit cone's acceptance angle and whose cross section shows uniform irradiance from near the exit mouth to infinity. (The pair is a beam angle transformer). The design of one pair of cones is discussed, also an experiment to map the irradiance of the emergent beam, and a raytracing program which models the cones fed by Lambertian flux. Experimental results compare favorably with raytrace results.

Replaceable filters and cones for flared-tubing connectors

NASA Technical Reports Server (NTRS)

Grant, L. E.; Howland, B. T.

1970-01-01

Connector is modified by machining the cone from one end before the fitting is bored to accommodate a metallic-filament type of slip-in filter. Thus, when surface of the cone is damaged, only the cone needs replacement.

Lrit1, a Retinal Transmembrane Protein, Regulates Selective Synapse Formation in Cone Photoreceptor Cells and Visual Acuity.

PubMed

Ueno, Akiko; Omori, Yoshihiro; Sugita, Yuko; Watanabe, Satoshi; Chaya, Taro; Kozuka, Takashi; Kon, Tetsuo; Yoshida, Satoyo; Matsushita, Kenji; Kuwahara, Ryusuke; Kajimura, Naoko; Okada, Yasushi; Furukawa, Takahisa

2018-03-27

In the vertebrate retina, cone photoreceptors play crucial roles in photopic vision by transmitting light-evoked signals to ON- and/or OFF-bipolar cells. However, the mechanisms underlying selective synapse formation in the cone photoreceptor pathway remain poorly understood. Here, we found that Lrit1, a leucine-rich transmembrane protein, localizes to the photoreceptor synaptic terminal and regulates the synaptic connection between cone photoreceptors and cone ON-bipolar cells. Lrit1-deficient retinas exhibit an aberrant morphology of cone photoreceptor pedicles, as well as an impairment of signal transmission from cone photoreceptors to cone ON-bipolar cells. Furthermore, we demonstrated that Lrit1 interacts with Frmpd2, a photoreceptor scaffold protein, and with mGluR6, an ON-bipolar cell-specific glutamate receptor. Additionally, Lrit1-null mice showed visual acuity impairments in their optokinetic responses. These results suggest that the Frmpd2-Lrit1-mGluR6 axis regulates selective synapse formation in cone photoreceptors and is essential for normal visual function. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Particle blender

DOEpatents

Willey, Melvin G.

1981-01-01

An infinite blender that achieves a homogeneous mixture of fuel microspheres is provided. Blending is accomplished by directing respective groups of desired particles onto the apex of a stationary coaxial cone. The particles progress downward over the cone surface and deposit in a space at the base of the cone that is described by a flexible band provided with a wide portion traversing and in continuous contact with the circumference of the cone base and extending upwardly therefrom. The band, being attached to the cone at a narrow inner end thereof, causes the cone to rotate on its arbor when the band is subsequently pulled onto a take-up spool. As a point at the end of the wide portion of the band passes the point where it is tangent to the cone, the blended particles are released into a delivery tube leading directly into a mold, and a plate mounted on the lower portion of the cone and positioned between the end of the wide portion of the band and the cone assures release of the particles only at the tangent point.

The Influence of Structure Heights and Opening Angles of Micro- and Nanocones on the Macroscopic Surface Wetting Properties

NASA Astrophysics Data System (ADS)

Schneider, Ling; Laustsen, Milan; Mandsberg, Nikolaj; Taboryski, Rafael

2016-02-01

We discuss the influence of surface structure, namely the height and opening angles of nano- and microcones on the surface wettability. We show experimental evidence that the opening angle of the cones is the critical parameter on sample superhydrophobicity, namely static contact angles and roll-off angles. The textured surfaces are fabricated on silicon wafers by using a simple one-step method of reactive ion etching at different processing time and gas flow rates. By using hydrophobic coating or hydrophilic surface treatment, we are able to switch the surface wettability from superhydrophilic to superhydrophobic without altering surface structures. In addition, we show examples of polymer replicas (polypropylene and poly(methyl methacrylate) with different wettability, fabricated by injection moulding using templates of the silicon cone-structures.

TOPICAL REVIEW: Experimental study of organic zero-gap conductor α-(BEDT-TTF)2I3

NASA Astrophysics Data System (ADS)

Tajima, Naoya; Kajita, Koji

2009-04-01

A zero-gap state with a Dirac cone type energy dispersion was discovered in the organic conductor α-(BEDT-TTF)2I3 under high hydrostatic pressures. This is the first two-dimensional (2D) zero-gap state discovered in bulk crystals with a layered structure. In contrast to the case of graphene, the Dirac cone in this system is highly anisotropic. The present system, therefore, provides a new type of massless Dirac fermion system with anisotropic Fermi velocity. This system exhibits remarkable transport phenomena characteristic to electrons on the Dirac cone type energy structure. The carrier density, written as n~T2, is a characteristic feature of the 2D zero-gap structure. On the other hand, the resistivity per layer (sheet resistance RS) is given as RS=h/e2 and is independent of temperature. The effect of a magnetic field on samples in the zero-gap system was examined. The difference between zero-gap conductors and conventional conductors is the appearance of a Landau level called the zero mode at the contact points when a magnetic field is applied normal to the conductive layer. Zero-mode Landau carriers give rise to strong negative out-of-plane magnetoresistance.

Recurrent abnormalities in conifer cones and the evolutionary origins of flower-like structures.

PubMed

Rudall, Paula J; Hilton, Jason; Vergara-Silva, Francisco; Bateman, Richard M

2011-03-01

Conifer cones are reproductive structures that are typically of restricted growth and either exclusively pollen-bearing (male) or exclusively ovule-bearing (female). Here, we review two common spontaneous developmental abnormalities of conifer cones: proliferated cones, in which the apex grows vegetatively, and bisexual cones, which possess both male and female structures. Emerging developmental genetic data, combined with evidence from comparative morphology, ontogeny and palaeobotany, provide new insights into the evolution of both cones and flowers, and prompt novel strategies for understanding seed-plant evolution. Copyright © 2010 Elsevier Ltd. All rights reserved.

Surface micro-structuring of silicon by excimer-laser irradiation in reactive atmospheres

NASA Astrophysics Data System (ADS)

Pedraza, A. J.; Fowlkes, J. D.; Jesse, S.; Mao, C.; Lowndes, D. H.

2000-12-01

The formation mechanisms of cones and columns by pulsed-laser irradiation in reactive atmospheres were studied using scanning electron microscopy and profilometry. Deep etching takes place in SF6- and O2- rich atmospheres and consequently, silicon-containing molecules and clusters are released. Transport of silicon from the etched/ablated regions to the tip of columns and cones and to the side of the cones is required because both structures, columns and cones, protrude above the initial surface. The laser-induced micro-structure is influenced not only by the nature but also by the partial pressure of the reactive gas in the atmosphere. Irradiation in Ar following cone formation in SF6 produced no additional growth but rather melting and resolidification. Subsequent irradiation using again a SF6 atmosphere lead to cone restructuring and growth resumption. Thus the effects of etching plus re-deposition that produce column/cone formation and growth are clearly separated from the effects of just melting. On the other hand, irradiation continued in air after first performed in SF6 resulted in: (a) an intense etching of the cones and a tendency to transform them into columns; (b) growth of new columns on top of the existing cones and (c) filamentary nano-structures coating the sides of the columns and cones.

Short-wavelength cone-opponent retinal ganglion cells in mammals.

PubMed

Marshak, David W; Mills, Stephen L

2014-03-01

In all of the mammalian species studied to date, the short-wavelength-sensitive (S) cones and the S-cone bipolar cells that receive their input are very similar, but the retinal ganglion cells that receive synapses from the S-cone bipolar cells appear to be quite different. Here, we review the literature on mammalian retinal ganglion cells that respond selectively to stimulation of S-cones and respond with opposite polarity to longer wavelength stimuli. There are at least three basic mechanisms to generate these color-opponent responses, including: (1) opponency is generated in the outer plexiform layer by horizontal cells and is conveyed to the ganglion cells via S-cone bipolar cells, (2) inputs from bipolar cells with different cone inputs and opposite response polarity converge directly on the ganglion cells, and (3) inputs from S-cone bipolar cells are inverted by S-cone amacrine cells. These are not mutually exclusive; some mammalian ganglion cells that respond selectively to S-cone stimulation seem to utilize at least two of them. Based on these findings, we suggest that the small bistratified ganglion cells described in primates are not the ancestral type, as proposed previously. Instead, the known types of ganglion cells in this pathway evolved from monostratified ancestral types and became bistratified in some mammalian lineages.

Microstructure and Texture Evolution in Double-Cone Samples of Ti-6Al-4V Alloy with Colony Preform Microstructure

NASA Astrophysics Data System (ADS)

Yang, Kun Vanna; Lim, Chao Voon Samuel; Zhang, Kai; Sun, Jifeng; Yang, Xiaoguang; Huang, Aijun; Wu, Xinhua; Davies, Christopher H.

2015-12-01

Heat-treated Ti-6Al-4V forged bar with colony microstructure was machined into double-cone-shaped samples for a series of isothermal uniaxial compression test at 1223 K (950 °C) with varying constant crosshead speeds of 12.5, 1.25, and 0.125 mms-1 to a height reduction of 70 pct. Another set of samples deformed under the same conditions were heat treated at 1173 K (900 °C) for an hour followed by water quench. Finite element modeling was used to provide the strains, strain rates, and temperature profiles of the hot compression samples, and the microstructure and texture evolution was examined at four positions on each sample, representative of different strain ranges. Lamellae fragmentation and kinking are the dominant microstructural features at lower strain range up to a maximum of 2.0, whereas globularization dominates at strains above 2.0 for the as-deformed samples. The globularization fraction generally increases with strain, or by post-deformation heat treatment, but fluctuates at lower strain. The grain size of the globular α is almost constant with strain and maximizes for samples with the lowest crosshead speed due to the longer deformation time. The globular α grain also coarsens because of post-deformation heat treatment, with its size increasing with strain level. With respect to texture evolution, a basal transverse ring and another component 30 deg from ND is determined for samples deformed at 12.5 mms-1, which is consistent with the temperature increase to close to β-transus from simulation results. The texture type remains unchanged with its intensity increased and spreads with increasing strain.

Four-Year Placebo-Controlled Trial of Docosahexaenoic Acid in X-Linked Retinitis Pigmentosa (DHAX Trial)

PubMed Central

Hoffman, Dennis R.; Hughbanks-Wheaton, Dianna K.; Pearson, N. Shirlene; Fish, Gary E.; Spencer, Rand; Takacs, Alison; Klein, Martin; Locke, Kirsten G.; Birch, David G.

2016-01-01

IMPORTANCE X-linked retinitis pigmentosa is a severe inherited retinal degenerative disease with a frequency of 1 in 100 000 persons. Because no cure is available for this orphan disease and treatment options are limited, slowing of disease progression would be a meaningful outcome. OBJECTIVE To determine whether high-dose docosahexaenoic acid (DHA), an ω-3 polyunsaturated fatty acid, slows progression of X-linked retinitis pigmentosa measured by cone electroretinography (ERG). DESIGN, SETTING, AND PARTICIPANTS A 4-year, single-site, randomized, placebo-controlled, double-masked phase 2 clinical trial at a research center specializing in medical retina. Seventy-eight male patients diagnosed as having X-linked retinitis pigmentosa were randomized to DHA or placebo. Data were omitted for 2 patients with non–X-linked retinitis pigmentosa and 16 patients who were unable to follow protocol during the first year. The remaining participants were tested annually and composed a modified intent-to-treat cohort (DHA group, n = 33; placebo group, n = 27). INTERVENTIONS All participants received a multivitamin and were randomly assigned to oral DHA (30 mg/kg/d) or placebo. MAIN OUTCOMES AND MEASURES The primary outcome was the rate of loss of cone ERG function. Secondary outcomes were rod and maximal ERG amplitudes and cone ERG implicit times. Capsule counts and red blood cell DHA levels were assessed to monitor adherence. RESULTS Average (6-month to 4-year) red blood cell DHA levels were 4-fold higher in the DHA group than in the placebo group (P < .001). There was no difference between the DHA and placebo groups in the rate of cone ERG functional loss (0.028 vs 0.022 log µV/y, respectively; P = .30). No group differences were evident for change in rod ERG (P = .27), maximal ERG (P = .65), or cone implicit time (no change over 4 years). The rate of cone loss (ie, event rate) was markedly reduced compared with rates in previous studies. No severe treatment-emergent adverse events were found. CONCLUSIONS AND RELEVANCE Long-term DHA supplementation was not effective in slowing the loss of cone or rod ERG function associated with X-linked retinitis pigmentosa. Participant dropout and lower-than-expected disease event rate limited power to detect statistical significance. A larger sample size, longer trial, and attainment of a target blood DHA level (13%) would be desirable. While DHA supplementation at 30 mg/kg/d does not present serious adverse effects, routine monitoring of gastrointestinal tolerance is prudent. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00100230 PMID:24805262

Individual and age-related variation in chromatic contrast adaptation

PubMed Central

Elliott, Sarah L.; Werner, John S.; Webster, Michael A.

2012-01-01

Precortical color channels are tuned primarily to the LvsM (stimulation of L and M cones varied, but S cone stimulation held constant) or SvsLM (stimulation of S cones varied, but L and M cone stimulation held constant) cone-opponent (cardinal) axes, but appear elaborated in the cortex to form higher-order mechanisms tuned to both cardinal and intermediate directions. One source of evidence for these higher-order mechanisms has been the selectivity of color contrast adaptation for noncardinal directions, yet the degree of this selectivity has varied widely across the small sample of observers tested in previous studies. This study explored the possible bases for this variation, and in particular tested whether it reflected age-related changes in the distribution or tuning of color mechanisms. Observers included 15 younger (18–22 years of age) and 15 older individuals (66–82), who adapted to temporal modulations along one of four chromatic axes (two cardinal and two intermediate axes) and then matched the hue and contrast of test stimuli lying along eight different directions in the equiluminant plane. All observers exhibited aftereffects that were selective for both the cardinal and intermediate directions, although selectivity was weaker for the intermediate axes. The degree of selectivity increased with the magnitude of adaptation for all axes, and thus adaptation strength alone may account for much of the variance in selectivity among observers. Older observers showed a stronger magnitude of adaptation thus, surprisingly, more conspicuous evidence for higher-order mechanisms. For both age groups the aftereffects were well predicted by response changes in chromatic channels with linear spectral sensitivities, and there was no evidence for weakened channel tuning with aging. The results suggest that higher-order mechanisms may become more exposed in observers or conditions in which the strength of adaptation is greater, and that both chromatic contrast adaptation and the cortical color coding it reflects remain largely intact in the aging visual system. PMID:22904356

A prototype table-top inverse-geometry volumetric CT system.

PubMed

Schmidt, Taly Gilat; Star-Lack, Josh; Bennett, N Robert; Mazin, Samuel R; Solomon, Edward G; Fahrig, Rebecca; Pelc, Norbert J

2006-06-01

A table-top volumetric CT system has been implemented that is able to image a 5-cm-thick volume in one circular scan with no cone-beam artifacts. The prototype inverse-geometry CT (IGCT) scanner consists of a large-area, scanned x-ray source and a detector array that is smaller in the transverse direction. The IGCT geometry provides sufficient volumetric sampling because the source and detector have the same axial, or slice direction, extent. This paper describes the implementation of the table-top IGCT scanner, which is based on the NexRay Scanning-Beam Digital X-ray system (NexRay, Inc., Los Gatos, CA) and an investigation of the system performance. The alignment and flat-field calibration procedures are described, along with a summary of the reconstruction algorithm. The resolution and noise performance of the prototype IGCT system are studied through experiments and further supported by analytical predictions and simulations. To study the presence of cone-beam artifacts, a "Defrise" phantom was scanned on both the prototype IGCT scanner and a micro CT system with a +/-5 cone angle for a 4.5-cm volume thickness. Images of inner ear specimens are presented and compared to those from clinical CT systems. Results showed that the prototype IGCT system has a 0.25-mm isotropic resolution and that noise comparable to that from a clinical scanner with equivalent spatial resolution is achievable. The measured MTF and noise values agreed reasonably well with theoretical predictions and computer simulations. The IGCT system was able to faithfully reconstruct the laminated pattern of the Defrise phantom while the micro CT system suffered severe cone-beam artifacts for the same object. The inner ear acquisition verified that the IGCT system can image a complex anatomical object, and the resulting images exhibited more high-resolution details than the clinical CT acquisition. Overall, the successful implementation of the prototype system supports the IGCT concept for single-rotation volumetric scanning free from cone-beam artifacts.

Evaporation From Soil Containers With Irregular Shapes

NASA Astrophysics Data System (ADS)

Assouline, Shmuel; Narkis, Kfir

2017-11-01

Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.

Cone and Rod Loss in Stargardt Disease Revealed by Adaptive Optics Scanning Light Ophthalmoscopy

PubMed Central

Song, Hongxin; Rossi, Ethan A.; Latchney, Lisa; Bessette, Angela; Stone, Edwin; Hunter, Jennifer J.; Williams, David R.; Chung, Mina

2015-01-01

Importance Stargardt disease (STGD1) is characterized by macular atrophy and flecks in the retinal pigment epithelium. The causative ABCA4 gene encodes a protein localizing to photoreceptor outer segments. The pathologic steps by which ABCA4 mutations lead to clinically detectable retinal pigment epithelium changes remain unclear. We investigated early STGD1 using adaptive optics scanning light ophthalmoscopy. Observations Adaptive optics scanning light ophthalmoscopy imaging of 2 brothers with early STGD1 and their unaffected parents was compared with conventional imaging. Cone and rod spacing were increased in both patients (P <.001) with a dark cone appearance. No foveal cones were detected in the older brother. In the younger brother, foveal cones were enlarged with low density (peak cone density, 48.3 × 103 cones/mm2). The ratio of cone to rod spacing was increased in both patients, with greater divergence from normal approaching the foveal center, indicating that cone loss predominates centrally and rod loss increases peripherally. Both parents had normal photoreceptor mosaics. Genetic testing revealed 3 disease-causing mutations. Conclusions and Relevance This study provides in vivo images of rods and cones in STGD1. Although the primary clinical features of STGD1 are retinal pigment epithelial lesions, adaptive optics scanning light ophthalmoscopy reveals increased cone and rod spacing in areas that appear normal in conventional images, suggesting that photoreceptor loss precedes clinically detectable retinal pigment epithelial disease in STGD1. PMID:26247787

Cone arrestin confers cone vision of high temporal resolution in zebrafish larvae.

PubMed

Renninger, Sabine L; Gesemann, Matthias; Neuhauss, Stephan C F

2011-02-01

Vision of high temporal resolution depends on careful regulation of photoresponse kinetics, beginning with the lifetime of activated photopigment. The activity of rhodopsin is quenched by high-affinity binding of arrestin to photoexcited phosphorylated photopigment, which effectively terminates the visual transduction cascade. This regulation mechanism is well established for rod photoreceptors, yet its role for cone vision is still controversial. In this study we therefore analyzed arrestin function in the cone-dominated vision of larval zebrafish. For both rod (arrS ) and cone (arr3 ) arrestin we isolated two paralogs, each expressed in the respective subset of photoreceptors. Labeling with paralog-specific antibodies revealed subfunctionalized expression of Arr3a in M- and L-cones, and Arr3b in S- and UV-cones. The inactivation of arr3a by morpholino knockdown technology resulted in a severe delay in photoresponse recovery which, under bright light conditions, was rate-limiting. Comparison to opsin phosphorylation-deficient animals confirmed the role of cone arrestin in late cone response recovery. Arr3a activity partially overlapped with the function of the cone-specific kinase Grk7a involved in initial response recovery. Behavioral measurements further revealed Arr3a deficiency to be sufficient to reduce temporal contrast sensitivity, providing evidence for the importance of arrestin in cone vision of high temporal resolution. © 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Highly effective phosphorylation by G protein-coupled receptor kinase 7 of light-activated visual pigment in cones.

PubMed

Tachibanaki, Shuji; Arinobu, Daisuke; Shimauchi-Matsukawa, Yoshie; Tsushima, Sawae; Kawamura, Satoru

2005-06-28

Cone photoreceptors show briefer photoresponses than rod photoreceptors. Our previous study showed that visual pigment phosphorylation, a quenching mechanism of light-activated visual pigment, is much more rapid in cones than in rods. Here, we measured the early time course of this rapid phosphorylation with good time resolution and directly compared it with the photoresponse time course in cones. At the time of photoresponse recovery, almost two phosphates were incorporated into a bleached cone pigment molecule, which indicated that the visual pigment phosphorylation coincides with the photoresponse recovery. The rapid phosphorylation in cones is attributed to very high activity of visual pigment kinase [G protein-coupled receptor kinase (GRK) 7] in cones. Because of this high activity, cone pigment is readily phosphorylated at very high bleach levels, which probably explains why cone photoresponses recover quickly even after a very bright light and do not saturate under intense background light. The high GRK7 activity is brought about by high content of a highly potent enzyme. The expression level of GRK7 was 10 times higher than that of rod kinase (GRK1), and the specific activity of a single GRK7 molecule was approximately 10 times higher than that of GRK1. The specific activity of GRK7 is the highest among the GRKs so far known. Our result seems to explain the response characteristics of cone photoreceptors in many aspects, including the nonsaturation of the cone responses during daylight vision.

A Nested or Composite Shatter Cone Structure in the South Range of Sudbury

NASA Astrophysics Data System (ADS)

Hurwitz, D. M.; Zanetti, M.; Lucas, M. P.; Anders, D.; Kramer, G.; Thomson, O.; Kring, D. A.; Osinski, G. R.

2013-08-01

In a recent survey of Sudbury shatter cones, we identified an outcrop of stacked, curvilinear foliations with well-developed, nested shatter cones that trend toward the apex of the foliations. We interpret this structure as a composite cone.

The nuclear high excitation outflow cone in NGC 1365

NASA Astrophysics Data System (ADS)

Per Lindblad, Olof; Hjelm, Maja; Jörsäter, Steven; Kristen, Helmuth

The morphology and kinematics of the high excitation outflow cone in the nuclear region of the Seyfert 1.5 galaxy NGC 1365 is investigated. An empirical model based on ground-based [OIII] emission line data consists of a somewhat hollow double cone with its apex at the Seyfert nucleus. The cone axis is well aligned in space with the normal to the symmetry plane of the galaxy and the position angle of its projection on the sky coincides closely with that of a jet-like radio feature. The opening angle of the cone is 100° and the orientation such that the line of sight to the Seyfert 1.5 nucleus falls inside the cone. The outflow velocities within the cone are accelerated and fall off towards the edge.

Effects of acidic amino acid antagonists upon the spectral properties of carp horizontal cells: circuitry of the outer retina.

PubMed

Mangel, S C; Ariel, M; Dowling, J E

1985-11-01

The acidic amino acid receptor antagonists, alpha-methylglutamate and alpha-aminoadipate, were applied to the carp retina to study their effects upon the spectral properties of horizontal cells and to elucidate the synaptic connections between horizontal cells and cones. Application of these antagonists strongly hyperpolarized the L-type cone horizontal cells and reduced the responses of these horizontal cells to red light more than to blue light. Application of Co2+ ions to the retina, a procedure which decreases transmitter release, also hyperpolarized the L-type cone horizontal cells but reduced the response of these horizontal cells to red and blue lights equally. These results suggest that red- or long wavelength-sensitive cones release a different transmitter onto L-type cone horizontal cells than do short wavelength-sensitive cones. Application of the acidic amino acid antagonists also revealed details of the feedback pathway from L-type cone horizontal cells to cones. Previous studies have shown that feedback varies directly with stimulus size and that the effects of feedback on the responses of cones are observed as a transient waveform at response onset (a large, hyperpolarizing potential that is quickly followed by a smaller plateau potential). Application of the acidic amino acid antagonists at a dose which partially hyperpolarized the horizontal cells selectively enhanced the response of the cells to blue lights, when full field, and not spot, stimuli were used. The antagonists also eliminated the transient at response onset. These findings are consistent with the presence of a feedback pathway from L-type cone horizontal cells to short wavelength cones but not to long (red-sensitive) cones.

Correlation of outer nuclear layer thickness with cone density values in patients with retinitis pigmentosa and healthy subjects.

PubMed

Menghini, Moreno; Lujan, Brandon J; Zayit-Soudry, Shiri; Syed, Reema; Porco, Travis C; Bayabo, Kristine; Carroll, Joseph; Roorda, Austin; Duncan, Jacque L

2014-12-16

We studied the correlation between outer nuclear layer (ONL) thickness and cone density in normal eyes and eyes with retinitis pigmentosa (RP). Spectral-domain optical coherence tomography (SD-OCT) scans were acquired using a displaced pupil entry position of the scanning beam to distinguish Henle's fiber layer from the ONL in 20 normal eyes (10 subjects) and 12 eyes with RP (7 patients). Cone photoreceptors were imaged using adaptive optics scanning laser ophthalmoscopy. The ONL thickness and cone density were measured at 0.5° intervals along the horizontal meridian through the fovea nasally and temporally. The ONL thickness and cone density were correlated using Spearman's rank correlation coefficient r. Cone densities averaged over the central 6° were lower in eyes with RP than normal, but showed high variability in both groups. The ONL thickness and cone density were significantly correlated when all retinal eccentricities were combined (r = 0.74); the correlation for regions within 0.5° to 1.5° eccentricity was stronger (r = 0.67) than between 1.5° and 3.0° eccentricity (r = 0.23). Although cone densities were lower between 0.5° and 1.5° in eyes with RP, ONL thickness measures at identical retinal locations were similar in the two groups (P = 0.31), and interindividual variation was high for ONL and cone density measures. Although ONL thickness and retinal eccentricity were important predictors of cone density, eccentricity was over 3 times more important. The ONL thickness and cone density were correlated in normal eyes and eyes with RP, but both were strongly correlated with retinal eccentricity, precluding estimation of cone density from ONL thickness. (ClinicalTrials.gov number, NCT00254605.). Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Correlation of Outer Nuclear Layer Thickness With Cone Density Values in Patients With Retinitis Pigmentosa and Healthy Subjects

PubMed Central

Menghini, Moreno; Lujan, Brandon J.; Zayit-Soudry, Shiri; Syed, Reema; Porco, Travis C.; Bayabo, Kristine; Carroll, Joseph; Roorda, Austin; Duncan, Jacque L.

2015-01-01

Purpose. We studied the correlation between outer nuclear layer (ONL) thickness and cone density in normal eyes and eyes with retinitis pigmentosa (RP). Methods. Spectral-domain optical coherence tomography (SD-OCT) scans were acquired using a displaced pupil entry position of the scanning beam to distinguish Henle's fiber layer from the ONL in 20 normal eyes (10 subjects) and 12 eyes with RP (7 patients). Cone photoreceptors were imaged using adaptive optics scanning laser ophthalmoscopy. The ONL thickness and cone density were measured at 0.5° intervals along the horizontal meridian through the fovea nasally and temporally. The ONL thickness and cone density were correlated using Spearman's rank correlation coefficient r. Results. Cone densities averaged over the central 6° were lower in eyes with RP than normal, but showed high variability in both groups. The ONL thickness and cone density were significantly correlated when all retinal eccentricities were combined (r = 0.74); the correlation for regions within 0.5° to 1.5° eccentricity was stronger (r = 0.67) than between 1.5° and 3.0° eccentricity (r = 0.23). Although cone densities were lower between 0.5° and 1.5° in eyes with RP, ONL thickness measures at identical retinal locations were similar in the two groups (P = 0.31), and interindividual variation was high for ONL and cone density measures. Although ONL thickness and retinal eccentricity were important predictors of cone density, eccentricity was over 3 times more important. Conclusions. The ONL thickness and cone density were correlated in normal eyes and eyes with RP, but both were strongly correlated with retinal eccentricity, precluding estimation of cone density from ONL thickness. (ClinicalTrials.gov number, NCT00254605.) PMID:25515570

Preliminary geologic map of the Sleeping Butte volcanic centers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowe, B.M.; Perry, F.V.

1991-07-01

The Sleeping Butte volcanic centers comprise two, spatially separate, small-volume (<0.1 km{sup 3}) basaltic centers. The centers were formed by mildly explosive Strombolian eruptions. The Little Black Peak cone consists of a main scoria cone, two small satellitic scoria mounds, and associated lobate lava flows that vented from sites at the base of the scoria cone. The Hidden Cone center consists of a main scoria cone that developed on the north-facing slope of Sleeping Butte. The center formed during two episodes. The first included the formation of the main scoria cone, and venting of aa lava flows from radial dikesmore » at the northeast base of the cone. The second included eruption of scoria-fall deposits from the summit crater. The ages of the Little Black Peak and the Hidden Cone are estimated to be between 200 to 400 ka based on the whole-rock K-Ar age determinations with large analytical undertainty. This age assignment is consistent with qualitative observations of the degree of soil development and geomorphic degradation of volcanic landforms. The younger episode of the Hidden Cone is inferred to be significantly younger and probably of Late Pleistocene or Holocene age. This is based on the absence of cone slope rilling, the absence of cone-slope apron deposits, and erosional unconformity between the two episodes, the poor horizon- development of soils, and the presence of fall deposits on modern alluvial surfaces. Paleomagnetic data show that the centers record similar but not identical directions of remanent magnetization. Paleomagnetic data have not been obtained for the youngest deposits of the Hidden Cone center. Further geochronology, soils, geomorphic, and petrology studies are planned of the Sleeping Butte volcanic centers 20 refs., 3 figs.« less

Cone structure imaged with adaptive optics scanning laser ophthalmoscopy in eyes with nonneovascular age-related macular degeneration.

PubMed

Zayit-Soudry, Shiri; Duncan, Jacque L; Syed, Reema; Menghini, Moreno; Roorda, Austin J

2013-11-15

To evaluate cone spacing using adaptive optics scanning laser ophthalmoscopy (AOSLO) in eyes with nonneovascular AMD, and to correlate progression of AOSLO-derived cone measures with standard measures of macular structure. Adaptive optics scanning laser ophthalmoscopy images were obtained over 12 to 21 months from seven patients with AMD including four eyes with geographic atrophy (GA) and four eyes with drusen. Adaptive optics scanning laser ophthalmoscopy images were overlaid with color, infrared, and autofluorescence fundus photographs and spectral domain optical coherence tomography (SD-OCT) images to allow direct correlation of cone parameters with macular structure. Cone spacing was measured for each visit in selected regions including areas over drusen (n = 29), at GA margins (n = 14), and regions without drusen or GA (n = 13) and compared with normal, age-similar values. Adaptive optics scanning laser ophthalmoscopy imaging revealed continuous cone mosaics up to the GA edge and overlying drusen, although reduced cone reflectivity often resulted in hyporeflective AOSLO signals at these locations. Baseline cone spacing measures were normal in 13/13 unaffected regions, 26/28 drusen regions, and 12/14 GA margin regions. Although standard clinical measures showed progression of GA in all study eyes, cone spacing remained within normal ranges in most drusen regions and all GA margin regions. Adaptive optics scanning laser ophthalmoscopy provides adequate resolution for quantitative measurement of cone spacing at the margin of GA and over drusen in eyes with AMD. Although cone spacing was often normal at baseline and remained normal over time, these regions showed focal areas of decreased cone reflectivity. These findings may provide insight into the pathophysiology of AMD progression. (ClinicalTrials.gov number, NCT00254605).

Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities. Annual report, February 24, 1993--February 23, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Law, V.J.

1994-07-07

The primary objective of this project was to evaluate the utility of a device called the ``beach cone`` in combating coastal erosion. Seven initial sites were selected for testing beach cones in a variety of geometric configurations, and six sites were actually used. Six hundred beach cones were installed at the six sites in late July and early August, 1992. An additional 109 cones were installed at an eighth site in December of 1992. Findings indicate that beach cones accreted significant amounts of materials along the beach of a barrier island. At the eighth installation the amount of accreted materialmore » was measured by surveys to be 2200 cubic meters (2900 cubic yards) in February of 1993, when the cones were found to have been completely covered by the material. The average increase in elevation was about 7 inches (0. 18 in) with a maximum buildup of 3 ft. (I in). At other test sites, accretion rates have been less dramatic but importantly, no significant additional erosion has occurred, which is a positive result. The cost of sediment accretion using beach cones was found to be about $13.72 per cubic yard of sand or approximately $500,000 per mile of beach, which would be much lower if the cones were mass produced. The survival of the cones through the fringes of Hurricane Andrew indicates that they can be anchored sufficiently to survive significant storms. The measurements of the cones settling rates indicate that this effect is negligible, does not hinder their effectiveness. We do not yet have sufficient data to state the categorical success of the beach cones, but results to date are encouraging.« less

Possible Tuff Cones In Isidis Planitia, Mars

NASA Astrophysics Data System (ADS)

Seabrook, A. M.; Rothery, D. A.; Bridges, J. C.; Wright, I. P.

The Beagle 2 lander of the ESA Mars Express mission will touch down on the martian surface in December 2003 to conduct a primarily exobiological mission. The landing site will be within Isidis Planitia, an 1100 km diameter impact basin. Isidis contains many sub-kilometre-sized cones. These can be found singly, in clusters, and in straight or arcuate chains extending many kilometres. In some areas of the basin these cones can occupy over 10% of the surface, with the most densely populated areas being in the older western half of the basin. There are few cones around the basin rim. There is also variation in the erosional state of the cones both across the basin, and within smaller areas, implying a range in time of formation for the cones. We currently favour a tuff cone origin as an explanation for these features. Tuff cones on Earth are rooted volcanic features formed at vents by the interaction between magma or magmatic heat and surface or near-surface water. Lava flows likely to be associated with at least some of the cones if they had a cinder cone (rooted eruptions at vents in a dry environment) origin are absent. This suggests the involvement of suffi- cient volatiles both to explosively fragment the erupting magma, and to cool the ejecta enough to prevent the formation of clastogenic flows. If our tuff cone interpretation is correct, this has implications for the presence, abundance and long-term persistence of sub-surface volatiles (water or carbon dioxide) on Mars. An understanding of the mechanism of formation of the Isidis cones will assist the characterisation of the basin in preparation for the landing of Beagle 2, by providing information about the history of volatiles and volcanism in the basin, and the processes that resulted in the surface we see today.

Branching habit and the allocation of reproductive resources in conifers

PubMed Central

Leslie, Andrew B.

2012-01-01

Background and Aims Correlated relationships between branch thickness, branch density, and twig and leaf size have been used extensively to study the evolution of plant canopy architecture, but fewer studies have explored the impact of these relationships on the allocation of reproductive resources. This study quantifies pollen cone production in conifers, which have similar basic reproductive biology but vary dramatically in branching habit, in order to test how differences in branch diameter influence pollen cone size and the density with which they are deployed in the canopy. Methods Measurements of canopy branch density, the number of cones per branch and cone size were used to estimate the amount of pollen cone tissues produced by 16 species in three major conifer clades. The number of pollen grains produced was also estimated using direct counts from individual pollen cones. Key Results The total amount of pollen cone tissues in the conifer canopy varied little among species and clades, although vegetative traits such as branch thickness, branch density and pollen cone size varied over several orders of magnitude. However, branching habit controls the way these tissues are deployed: taxa with small branches produce small pollen cones at a high density, while taxa with large branches produce large cones relatively sparsely. Conclusions Conifers appear to invest similar amounts of energy in pollen production independent of branching habit. However, similar associations between branch thickness, branch density and pollen cone size are seen across conifers, including members of living and extinct groups not directly studied here. This suggests that reproductive features relating to pollen cone size are in large part a function of the evolution of vegetative morphology and branching habit. PMID:22782240

Selective Stimulation of Penumbral Cones Reveals Perception in the Shadow of Retinal Blood Vessels

PubMed Central

Spitschan, Manuel; Aguirre, Geoffrey K.; Brainard, David H.

2015-01-01

In 1819, Johann Purkinje described how a moving light source that displaces the shadow of the retinal blood vessels to adjacent cones can produce the entopic percept of a branching tree. Here, we describe a novel method for producing a similar percept. We used a device that mixes 56 narrowband primaries under computer control, in conjunction with the method of silent substitution, to present observers with a spectral modulation that selectively targeted penumbral cones in the shadow of the retinal blood vessels. Such a modulation elicits a clear Purkinje-tree percept. We show that the percept is specific to penumbral L and M cone stimulation and is not produced by selective penumbral S cone stimulation. The Purkinje-tree percept was strongest at 16 Hz and fell off at lower (8 Hz) and higher (32 Hz) temporal frequencies. Selective stimulation of open-field cones that are not in shadow, with penumbral cones silenced, also produced the percept, but it was not seen when penumbral and open-field cones were modulated together. This indicates the need for spatial contrast between penumbral and open-field cones to create the Purkinje-tree percept. Our observation provides a new means for studying the response of retinally stabilized images and demonstrates that penumbral cones can support spatial vision. Further, the result illustrates a way in which silent substitution techniques can fail to be silent. We show that inadvertent penumbral cone stimulation can accompany melanopsin-directed modulations that are designed only to silence open-field cones. This in turn can result in visual responses that might be mistaken as melanopsin-driven. PMID:25897842

Rayleigh matches in carriers of inherited color vision defects: the contribution from the third L/M photopigment.

PubMed

Sun, Yang; Shevell, Steven K

2008-01-01

The mother or daughter of a male with an X-chromosome-linked red/green color defect is an obligate carrier of the color deficient gene array. According to the Lyonization hypothesis, a female carrier's defective gene is expressed and thus carriers may have more than two types of pigments in the L/M photopigment range. An open question is how a carrier's third cone pigment in the L/M range affects the postreceptoral neural signals encoding color. Here, a model considered how the signal from the third pigment pools with signals from the normal's two pigments in the L/M range. Three alternative assumptions were considered for the signal from the third cone pigment: it pools with the signal from (1) L cones, (2) M cones, or (3) both types of cones. Spectral-sensitivity peak, optical density, and the relative number of each cone type were factors in the model. The model showed that differences in Rayleigh matches among carriers can be due to individual differences in the number of the third type of L/M cone, and the spectral sensitivity peak and optical density of the third L/M pigment; surprisingly, however, individual differences in the cone ratio of the other two cone types (one L and the other M) did not affect the match. The predicted matches were compared to Schmidt's (1934/1955) report of carriers' Rayleigh matches. For carriers of either protanomaly or deuteranomaly, these matches were not consistent with the signal from the third L/M pigment combining with only the signal from M cones. The matches could be accounted for by pooling the third-pigment's response with L-cone signals, either exclusively or randomly with M-cone responses as well.

A study of factors affecting the human cone photoreceptor density measured by adaptive optics scanning laser ophthalmoscope.

PubMed

Park, Sung Pyo; Chung, Jae Keun; Greenstein, Vivienne; Tsang, Stephen H; Chang, Stanley

2013-03-01

To investigate the variation in human cone photoreceptor packing density with various demographic or clinical factors, cone packing density was measured using a Canon prototype adaptive optics scanning laser ophthalmoscope and compared as a function of retinal eccentricity, refractive error, axial length, age, gender, race/ethnicity and ocular dominance. We enrolled 192 eyes of 192 subjects with no ocular pathology. Cone packing density was measured at three different retinal eccentricities (0.5 mm, 1.0 mm, and 1.5 mm from the foveal center) along four meridians. Cone density decreased from 32,200 to 11,600 cells/mm(2) with retinal eccentricity (0.5 mm to 1.5 mm from the fovea, P < 0.001). A trend towards a slightly negative correlation was observed between age and density (r = -0.117, P = 0.14). There was, however, a statistically significant negative correlation (r = -0.367, P = 0.003) between axial length and cone density. Gender, ocular dominance, and race/ethnicity were not important determinants of cone density (all, P > 0.05). In addition, to assess the spatial arrangement of the cone mosaics, the nearest-neighbor distances (NNDs) and the Voronoi domains were analyzed. The results of NND and Voronoi analysis were significantly correlated with the variation of the cone density. Average NND and Voronoi area were gradually increased (all, P ≤ 0.001) and the degree of regularity of the cone mosaics was decreased (P ≤ 0.001) with increasing retinal eccentricity. In conclusion, we demonstrated cone packing density decreases as a function of retinal eccentricity and axial length and the results of NND and Voronoi analysis is a useful index for cone mosaics arrangements. The results also serve as a reference for further studies designed to detect or monitor cone photoreceptors in patients with retinal diseases. Copyright © 2012 Elsevier Ltd. All rights reserved.

A study of factors affecting the human cone photoreceptor density measured by adaptive optics scanning laser ophthalmoscope

PubMed Central

Park, Sung Pyo; Chung, Jae Keun; Greenstein, Vivienne; Tsang, Stephen H.; Chang, Stanley

2015-01-01

To investigate the variation in human cone photoreceptor packing density with various demographic or clinical factors, cone packing density was measured using a Canon prototype adaptive optics scanning laser ophthalmoscope and compared as a function of retinal eccentricity, refractive error, axial length, age, gender, race/ethnicity and ocular dominance. We enrolled 192 eyes of 192 subjects with no ocular pathology. Cone packing density was measured at three different retinal eccentricities (0.5 mm, 1.0 mm, and 1.5 mm from the foveal center) along four meridians. Cone density decreased from 32,200 to 11,600 cells/mm2 with retinal eccentricity (0.5 mm to 1.5 mm from the fovea, P < 0.001). A trend towards a slightly negative correlation was observed between age and density (r = −0.117, P = 0.14). There was, however, a statistically significant negative correlation (r = −0.367, P = 0.003) between axial length and cone density. Gender, ocular dominance, and race/ethnicity were not important determinants of cone density (all, P > 0.05). In addition, to assess the spatial arrangement of the cone mosaics, the nearest-neighbor distances (NNDs) and the Voronoi domains were analyzed. The results of NND and Voronoi analysis were significantly correlated with the variation of the cone density. Average NND and Voronoi area were gradually increased (all, P ≤ 0.001) and the degree of regularity of the cone mosaics was decreased (P ≤ 0.001) with increasing retinal eccentricity. In conclusion, we demonstrated cone packing density decreases as a function of retinal eccentricity and axial length and the results of NND and Voronoi analysis is a useful index for cone mosaics arrangements. The results also serve as a reference for further studies designed to detect or monitor cone photoreceptors in patients with retinal diseases. PMID:23276813

Phosphorylation-independent suppression of light-activated visual pigment by arrestin in carp rods and cones.

PubMed

Tomizuka, Junko; Tachibanaki, Shuji; Kawamura, Satoru

2015-04-10

Visual pigment in photoreceptors is activated by light. Activated visual pigment (R*) is believed to be inactivated by phosphorylation of R* with subsequent binding of arrestin. There are two types of photoreceptors, rods and cones, in the vertebrate retina, and they express different subtypes of arrestin, rod and cone type. To understand the difference in the function between rod- and cone-type arrestin, we first identified the subtype of arrestins expressed in rods and cones in carp retina. We found that two rod-type arrestins, rArr1 and rArr2, are co-expressed in a rod and that a cone-type arrestin, cArr1, is expressed in blue- and UV-sensitive cones; the other cone-type arrestin, cArr2, is expressed in red- and green-sensitive cones. We quantified each arrestin subtype and estimated its concentration in the outer segment of a rod or a cone in the dark; they were ∼0.25 mm (rArr1 plus rArr2) in a rod and 0.6-0.8 mm (cArr1 or cArr2) in a cone. The effect of each arrestin was examined. In contrast to previous studies, both rod and cone arrestins suppressed the activation of transducin in the absence of visual pigment phosphorylation, and all of the arrestins examined (rArr1, rArr2, and cArr2) bound transiently to most probably nonphosphorylated R*. One rod arrestin, rArr2, bound firmly to phosphorylated pigment, and the other two, rArr1 and cArr2, once bound to phosphorylated R* but dissociated from it during incubation. Our results suggested a novel mechanism of arrestin effect on the suppression of the R* activity in both rods and cones. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Chloride currents in cones modify feedback from horizontal cells to cones in goldfish retina

PubMed Central

Endeman, Duco; Fahrenfort, Iris; Sjoerdsma, Trijntje; Steijaert, Marvin; ten Eikelder, Huub; Kamermans, Maarten

2012-01-01

In neuronal systems, excitation and inhibition must be well balanced to ensure reliable information transfer. The cone/horizontal cell (HC) interaction in the retina is an example of this. Because natural scenes encompass an enormous intensity range both in temporal and spatial domains, the balance between excitation and inhibition in the outer retina needs to be adaptable. How this is achieved is unknown. Using electrophysiological techniques in the isolated retina of the goldfish, it was found that opening Ca2+-dependent Cl− channels in recorded cones reduced the size of feedback responses measured in both cones and HCs. Furthermore, we show that cones express Cl− channels that are gated by GABA released from HCs. Similar to activation of ICl(Ca), opening of these GABA-gated Cl− channels reduced the size of light-induced feedback responses both in cones and HCs. Conversely, application of picrotoxin, a blocker of GABAA and GABAC receptors, had the opposite effect. In addition, reducing GABA release from HCs by blocking GABA transporters also led to an increase in the size of feedback. Because the independent manipulation of Ca2+-dependent Cl− currents in individual cones yielded results comparable to bath-applied GABA, it was concluded that activation of either Cl− current by itself is sufficient to reduce the size of HC feedback. However, additional effects of GABA on outer retinal processing cannot be excluded. These results can be accounted for by an ephaptic feedback model in which a cone Cl− current shunts the current flow in the synaptic cleft. The Ca2+-dependent Cl− current might be essential to set the initial balance between the feedforward and the feedback signals active in the cone HC synapse. It prevents that strong feedback from HCs to cones flood the cone with Ca2+. Modulation of the feedback strength by GABA might play a role during light/dark adaptation, adjusting the amount of negative feedback to the signal to noise ratio of the cone output. PMID:22890705

Distinct and Atypical Intrinsic and Extrinsic Cell Death Pathways between Photoreceptor Cell Types upon Specific Ablation of Ranbp2 in Cone Photoreceptors

PubMed Central

Cho, Kyoung-in; Yu, Minzhong; Hao, Ying; Qiu, Sunny; Pillai, Indulekha C. L.; Peachey, Neal S.; Ferreira, Paulo A.

2013-01-01

Non-autonomous cell-death is a cardinal feature of the disintegration of neural networks in neurodegenerative diseases, but the molecular bases of this process are poorly understood. The neural retina comprises a mosaic of rod and cone photoreceptors. Cone and rod photoreceptors degenerate upon rod-specific expression of heterogeneous mutations in functionally distinct genes, whereas cone-specific mutations are thought to cause only cone demise. Here we show that conditional ablation in cone photoreceptors of Ran-binding protein-2 (Ranbp2), a cell context-dependent pleiotropic protein linked to neuroprotection, familial necrotic encephalopathies, acute transverse myelitis and tumor-suppression, promotes early electrophysiological deficits, subcellular erosive destruction and non-apoptotic death of cones, whereas rod photoreceptors undergo cone-dependent non-autonomous apoptosis. Cone-specific Ranbp2 ablation causes the temporal activation of a cone-intrinsic molecular cascade highlighted by the early activation of metalloproteinase 11/stromelysin-3 and up-regulation of Crx and CoREST, followed by the down-modulation of cone-specific phototransduction genes, transient up-regulation of regulatory/survival genes and activation of caspase-7 without apoptosis. Conversely, PARP1+-apoptotic rods develop upon sequential activation of caspase-9 and caspase-3 and loss of membrane permeability. Rod photoreceptor demise ceases upon cone degeneration. These findings reveal novel roles of Ranbp2 in the modulation of intrinsic and extrinsic cell death mechanisms and pathways. They also unveil a novel spatiotemporal paradigm of progression of neurodegeneration upon cell-specific genetic damage whereby a cone to rod non-autonomous death pathway with intrinsically distinct cell-type death manifestations is triggered by cell-specific loss of Ranbp2. Finally, this study casts new light onto cell-death mechanisms that may be shared by human dystrophies with distinct retinal spatial signatures as well as with other etiologically distinct neurodegenerative disorders. PMID:23818861

Design and development of C-arm based cone-beam CT for image-guided interventions: initial results

NASA Astrophysics Data System (ADS)

Chen, Guang-Hong; Zambelli, Joseph; Nett, Brian E.; Supanich, Mark; Riddell, Cyril; Belanger, Barry; Mistretta, Charles A.

2006-03-01

X-ray cone-beam computed tomography (CBCT) is of importance in image-guided intervention (IGI) and image-guided radiation therapy (IGRT). In this paper, we present a cone-beam CT data acquisition system using a GE INNOVA 4100 (GE Healthcare Technologies, Waukesha, Wisconsin) clinical system. This new cone-beam data acquisition mode was developed for research purposes without interfering with any clinical function of the system. It provides us a basic imaging pipeline for more advanced cone-beam data acquisition methods. It also provides us a platform to study and overcome the limiting factors such as cone-beam artifacts and limiting low contrast resolution in current C-arm based cone-beam CT systems. A geometrical calibration method was developed to experimentally determine parameters of the scanning geometry to correct the image reconstruction for geometric non-idealities. Extensive phantom studies and some small animal studies have been conducted to evaluate the performance of our cone-beam CT data acquisition system.

Mouse rods signal through gap junctions with cones.

PubMed

Asteriti, Sabrina; Gargini, Claudia; Cangiano, Lorenzo

2014-01-01

Rod and cone photoreceptors are coupled by gap junctions (GJs), relatively large channels able to mediate both electrical and molecular communication. Despite their critical location in our visual system and evidence that they are dynamically gated for dark/light adaptation, the full impact that rod-cone GJs can have on cone function is not known. We recorded the photovoltage of mouse cones and found that the initial level of rod input increased spontaneously after obtaining intracellular access. This process allowed us to explore the underlying coupling capacity to rods, revealing that fully coupled cones acquire a striking rod-like phenotype. Calcium, a candidate mediator of the coupling process, does not appear to be involved on the cone side of the junctional channels. Our findings show that the anatomical substrate is adequate for rod-cone coupling to play an important role in vision and, possibly, in biochemical signaling among photoreceptors. DOI: http://dx.doi.org/10.7554/eLife.01386.001.

Mouse rods signal through gap junctions with cones

PubMed Central

Asteriti, Sabrina; Gargini, Claudia; Cangiano, Lorenzo

2014-01-01

Rod and cone photoreceptors are coupled by gap junctions (GJs), relatively large channels able to mediate both electrical and molecular communication. Despite their critical location in our visual system and evidence that they are dynamically gated for dark/light adaptation, the full impact that rod–cone GJs can have on cone function is not known. We recorded the photovoltage of mouse cones and found that the initial level of rod input increased spontaneously after obtaining intracellular access. This process allowed us to explore the underlying coupling capacity to rods, revealing that fully coupled cones acquire a striking rod-like phenotype. Calcium, a candidate mediator of the coupling process, does not appear to be involved on the cone side of the junctional channels. Our findings show that the anatomical substrate is adequate for rod–cone coupling to play an important role in vision and, possibly, in biochemical signaling among photoreceptors. DOI: http://dx.doi.org/10.7554/eLife.01386.001 PMID:24399457

Vertical microbial community variability of carbonate-based cones may provide insight into ancient conical stromatolite formation

NASA Astrophysics Data System (ADS)

Bradley, James; Daille, Leslie; Trivedi, Christopher; Bojanowski, Caitlin; Nunn, Heather; Stamps, Blake; Johnson, Hope; Stevenson, Bradley; Berelson, Will; Corsetti, Frank; Spear, John

2016-04-01

Stromatolite morphogenesis is poorly understood, and the process by which microbial mats become mineralized is a primary question in microbialite formation. Ancient conical stromatolites are primarily carbonate-based whereas the few modern analogues in hot springs are either non-mineralized or mineralized by silica. A team from the 2015 International GeoBiology Course investigated carbonate-rich microbial cones from near Little Hot Creek (LHC), Long Valley Caldera, California, to investigate how conical stromatolites might form in a hot spring carbonate system. The cones rise up from a layered microbial mat on the east side of a 45° C pool with very low flow that is super-saturated with respect to CaCO3. Cone structures are 8-30 mm in height, are rigid and do not deform when removed from the pool. Morphological characterization through environmental scanning electronic microscopy revealed that the cone structure is maintained by a matrix of intertwining microbial filaments around carbonate grains. This matrix gives rise to cone-filaments that are arranged vertically or horizontally, and provides further stability to the cone. Preliminary 16S rRNA gene analysis indicated variability of community composition between different vertical levels of the cone. The cone tip had comparatively greater abundance of filamentous cyanobacteria including Leptolingbya, Phormidium and Isosphaera and fewer heterotrophs (e.g. Chloroflexi) compared to the cone bottom. This supports the hypothesis that cone formation may depend on the differential abundance of the microbial community and their potential functional roles. Metagenomic analyses of the cones revealed potential genes related to chemotaxis and motility. Specifically, a genomic bin identified as a member of the genus Isosphaera contained an hmp chemotaxis operon implicated in gliding motility in the cyanobacterium Nostoc punctiforme. Isosphaera is a Planctomycete shown to have phototactic capabilities, and may play a role in conjunction with cyanobacteria in the vertical formation of the cones. This analysis of actively growing cones indicates a complex interplay of geochemistry and microbiology that form structures which can serve as models for processes that occurred in the past and are preserved in the rock record.

Seed release in serotinous lodgepole pine forests after mountain pine beetle outbreak.

PubMed

Teste, François P; Lieffers, Victor J; Landhausser, Simon M

2011-01-01

There are concerns that large-scale stand mortality due to mountain pine beetle (MPB) could greatly reduce natural regeneration of serotinous Rocky Mountain (RM) lodgepole pine (Pinus contorta var. latifolia) because the closed cones are held in place without the fire cue for cone opening. We selected 20 stands (five stands each of live [control], 3 years since MPB [3-yr-MPB], 6 years since MPB [6-yr-MPB], and 9 years since MPB [9-yr-MPB] mortality) in north central British Columbia, Canada. The goal was to determine partial loss of serotiny due to fall of crown-stored cones via breakage of branches and in situ opening of canopy cones throughout the 2008 and 2009 growing seasons. We also quantified seed release by the opening of forest-floor cones, loss of seed from rodent predation, and cone burial. Trees killed by MPB three years earlier dropped approximately 3.5 times more cones via branch breakage compared to live stands. After six years, MPB-killed stands had released 45% of their canopy seed bank through cone opening, cone fall due to breakage, and squirrel predation. Further losses of canopy seed banks are expected with time since we found 9-yr-MPB stands had 38% more open canopy cones. This was countered by the development of a modest forest-floor seed bank (6% of the original canopy seed bank) from burial of cones; this seed bank may be ecologically important if a fire or anthropogenic disturbance reexposes these cones. If adequate levels of regeneration are to occur, disturbances to create seedbeds must occur shortly after tree mortality, before the seed banks are lost. Our findings also suggest that the sustained seed rain (over at least nine years) after MPB outbreak may be beneficial for population growth of ground-foraging vertebrates. Our study adds insight to the seed ecology of serotinous pines under a potentially continental-wide insect outbreak, threatening vast forests adapted to regeneration after fire. Key words: biotic disturbance; cone burial; cone opening; Dendroctonus ponderosae; ground-foraging vertebrates; mountain pine beetle; natural regeneration; Pinus contorta var. latifolia; Rocky Mountain lodgepole pine; seed banks; serotiny (canopy seed storage); Tamiasciurus hudsonicus.

Cone photopigment in older subjects: decreased optical density in early age-related macular degeneration

NASA Astrophysics Data System (ADS)

Elsner, Ann E.; Burns, Stephen A.; Weiter, John J.

2002-01-01

We measured changes to cone photoreceptors in patients with early age-related macular degeneration. The data of 53 patients were compared with normative data for color matching measurements of long- and middle-wavelength-sensitive cones in the central macula. A four-parameter model quantified cone photopigment optical density and kinetics. Cone photopigment optical density was on average less for the patients than for normal subjects and was uncorrelated with visual acuity. More light was needed to reduce the photopigment density by 50% in the steady state for patients. These results imply that cone photopigment optical density is reduced by factors other than slowed kinetics.

When Do Short-Wave Cones Signal Blue or Red? A Solution Introducing the Concept of Primary and Secondary Cone Outputs

PubMed Central

2016-01-01

A recent paper by Oh and Sakata investigates the “incompletely solved mystery” of how the three cone responses map onto perceived hue, and particularly the S cone’s well-known problematic contribution to blueness and redness. Citing previous workers, they argue the twentieth century traditional multistage model does not satisfactorily account for color appearance. In their experiment, increasing S cone excitation with shortening wavelength from about 480–460 nm increased perceived blueness up to the unique Blue point at 470 nm, when (a) it began decreasing and (b) redness perception began increasing. The authors asked, What mechanism can be responsible for such functions? I demonstrate a solution. First, it is shown the problem does not lie in the traditional opponent color chromatic responses yellow-blue, red-green (y-b, r-g, which accurately predict the above functions), but in the traditional multistage model of mapping cone responses to chromatic response functions. Arguably, this is due to the S cone’s hypothetically signaling both blueness and redness by the same mechanism rather than by different, independent, mechanisms. Hence a new distinction or mechanism is proposed for a more accurate model, that introduces the new terms primary and secondary cone outputs. However, this distinction requires that the cones S, M, L each directly produce one of the three spectral chromatic responses b, g, y. Such a model was recently published, based on extremely high correlation of SML cone responsivities with the three spectral (bgy) chromatic responses. This model encodes the former directly onto the latter one-to-one as cone primary outputs, whilst S and L cones have a further or secondary function where each produces one of the two spectral lobes of r chromatic response. The proposed distinction between primary and secondary cone outputs is a new concept and useful tool in detailing cone outputs to chromatic channels, and provides a solution to the above “incompletely solved mystery.” Thus the S cone has a primary output producing the total b chromatic response and a secondary output that shares with the L cone the production of r chromatic response, thus aligning with Oh and Sokata’s results. The model similarly maps L cone to yellowness as primary output and to redness as secondary output. PMID:27110938

Cone-beam computed tomography fusion and navigation for real-time positron emission tomography-guided biopsies and ablations: a feasibility study.

PubMed

Abi-Jaoudeh, Nadine; Mielekamp, Peter; Noordhoek, Niels; Venkatesan, Aradhana M; Millo, Corina; Radaelli, Alessandro; Carelsen, Bart; Wood, Bradford J

2012-06-01

To describe a novel technique for multimodality positron emission tomography (PET) fusion-guided interventions that combines cone-beam computed tomography (CT) with PET/CT before the procedure. Subjects were selected among patients scheduled for a biopsy or ablation procedure. The lesions were not visible with conventional imaging methods or did not have uniform uptake on PET. Clinical success was defined by adequate histopathologic specimens for molecular profiling or diagnosis and by lack of enhancement on follow-up imaging for ablation procedures. Time to target (time elapsed between the completion of the initial cone-beam CT scan and first tissue sample or treatment), total procedure time (time from the moment the patient was on the table until the patient was off the table), and number of times the needle was repositioned were recorded. Seven patients underwent eight procedures (two ablations and six biopsies). Registration and procedures were completed successfully in all cases. Clinical success was achieved in all biopsy procedures and in one of the two ablation procedures. The needle was repositioned once in one biopsy procedure only. On average, the time to target was 38 minutes (range 13-54 min). Total procedure time was 95 minutes (range 51-240 min, which includes composite ablation). On average, fluoroscopy time was 2.5 minutes (range 1.3-6.2 min). An integrated cone-beam CT software platform can enable PET-guided biopsies and ablation procedures without the need for additional specialized hardware. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

Automated Photoreceptor Cell Identification on Nonconfocal Adaptive Optics Images Using Multiscale Circular Voting.

PubMed

Liu, Jianfei; Jung, HaeWon; Dubra, Alfredo; Tam, Johnny

2017-09-01

Adaptive optics scanning light ophthalmoscopy (AOSLO) has enabled quantification of the photoreceptor mosaic in the living human eye using metrics such as cell density and average spacing. These rely on the identification of individual cells. Here, we demonstrate a novel approach for computer-aided identification of cone photoreceptors on nonconfocal split detection AOSLO images. Algorithms for identification of cone photoreceptors were developed, based on multiscale circular voting (MSCV) in combination with a priori knowledge that split detection images resemble Nomarski differential interference contrast images, in which dark and bright regions are present on the two sides of each cell. The proposed algorithm locates dark and bright region pairs, iteratively refining the identification across multiple scales. Identification accuracy was assessed in data from 10 subjects by comparing automated identifications with manual labeling, followed by computation of density and spacing metrics for comparison to histology and published data. There was good agreement between manual and automated cone identifications with overall recall, precision, and F1 score of 92.9%, 90.8%, and 91.8%, respectively. On average, computed density and spacing values using automated identification were within 10.7% and 11.2% of the expected histology values across eccentricities ranging from 0.5 to 6.2 mm. There was no statistically significant difference between MSCV-based and histology-based density measurements (P = 0.96, Kolmogorov-Smirnov 2-sample test). MSCV can accurately detect cone photoreceptors on split detection images across a range of eccentricities, enabling quick, objective estimation of photoreceptor mosaic metrics, which will be important for future clinical trials utilizing adaptive optics.

M to L cone ratios determine eye sizes and baseline refractions in chickens.

PubMed

Gisbert, Sandra; Schaeffel, Frank

2018-07-01

Following a hypothesis raised by M. and J. Neitz, Seattle, we have tested whether the abundance and the ratio of Long wavelength-sensitive (L) to Middle wavelength-sensitive (M) cones may affect eye size and development of myopia in the chicken. Fourteen chickens were treated with frosted plastic diffusers in front of one eye on day 10 post-hatching for a period of 7 days to induce deprivation myopia. Ocular dimensions were measured by A-scan ultrasonography at the beginning and at the end of the treatment and development of refractive state was tracked using infrared photorefraction. At the end of the treatment period, L and M cone densities and ratios were analyzed in retinal flat mounts of both myopic and control eyes, using the red and yellow oil droplets as markers. Because large numbers of cones were counted (>10000), software was written in Visual C++ for automated cone detection and density analysis. (1) On average, 9.7 ± 1.7D of deprivation myopia was induced in 7 days (range from 6.8D to 13.7D) with an average increase in axial length by 0.65 ± 0.20 mm (range 0.42 mm-1.00 mm), (2) the increase in vitreous chamber depth was correlated with the increase in myopic refractive error, (3) average central M cone densities were 10,498 cells/mm 2 , and L cone densities 9574 cells/mm 2 . In the periphery, M cone densities were 6343 cells/mm 2 and L cones 5735 cells/mm 2 (4) M to L cone ratios were highly correlated in both eyes of each animal (p < 0.01 in all cases), (5) the most striking finding was that ratios of M to L cones were significantly correlated with vitreous chamber depths and refractive states in the control eyes with normal vision, both in the central and peripheral retinas (p < 0.05 to p < 0.01), (6) M to L cone ratios did however not predict the amount of deprivation myopia that could be induced. M and L cone ratios are most likely genetically determined in each animal. The more L cones, the deeper the vitreous chambers and the more myopic were the refractions in eyes. M to L cone ratios may determine the set point of emmetropization and thereby ultimately the probability of becoming myopic. Deprivation myopia was not determined by M to L cone ratios. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Wind-tunnel investigation of the aerodynamic characteristics of the Standard Dynamics Model in coning motion at Mach 0.6

NASA Technical Reports Server (NTRS)

Jermey, C.; Schiff, L. B.

1985-01-01

A series of wind-tunnel tests have been conducted on the Standard Dynamics Model (a simplified generic fighter-aircraft shape) undergoing coning motion at Mach 0.6. Six-component force and moment data are presented for a range of angles of attack, sideslip and coning rates. At the relatively low nondimensional coning rates employed, the lateral aerodynamic charactersitics generally show a linear variation with coning rate.

Adaptation of cone pigments found in green rods for scotopic vision through a single amino acid mutation

PubMed Central

Kojima, Keiichi; Matsutani, Yuki; Yamashita, Takahiro; Yanagawa, Masataka; Imamoto, Yasushi; Yamano, Yumiko; Wada, Akimori; Hisatomi, Osamu; Nishikawa, Kanto; Sakurai, Keisuke; Shichida, Yoshinori

2017-01-01

Most vertebrate retinas contain a single type of rod for scotopic vision and multiple types of cones for photopic and color vision. The retinas of certain amphibian species uniquely contain two types of rods: red rods, which express rhodopsin, and green rods, which express a blue-sensitive cone pigment (M1/SWS2 group). Spontaneous activation of rhodopsin induced by thermal isomerization of the retinal chromophore has been suggested to contribute to the rod’s background noise, which limits the visual threshold for scotopic vision. Therefore, rhodopsin must exhibit low thermal isomerization rate compared with cone visual pigments to adapt to scotopic condition. In this study, we determined whether amphibian blue-sensitive cone pigments in green rods exhibit low thermal isomerization rates to act as rhodopsin-like pigments for scotopic vision. Anura blue-sensitive cone pigments exhibit low thermal isomerization rates similar to rhodopsin, whereas Urodela pigments exhibit high rates like other vertebrate cone pigments present in cones. Furthermore, by mutational analysis, we identified a key amino acid residue, Thr47, that is responsible for the low thermal isomerization rates of Anura blue-sensitive cone pigments. These results strongly suggest that, through this mutation, anurans acquired special blue-sensitive cone pigments in their green rods, which could form the molecular basis for scotopic color vision with normal red rods containing green-sensitive rhodopsin. PMID:28484015

Differential encoding of spatial information among retinal on cone bipolar cells

PubMed Central

Purgert, Robert J.

2015-01-01

The retina is the first stage of visual processing. It encodes elemental features of visual scenes. Distinct cone bipolar cells provide the substrate for this to occur. They encode visual information, such as color and luminance, a principle known as parallel processing. Few studies have directly examined whether different forms of spatial information are processed in parallel among cone bipolar cells. To address this issue, we examined the spatial information encoded by mouse ON cone bipolar cells, the subpopulation excited by increments in illumination. Two types of spatial processing were identified. We found that ON cone bipolar cells with axons ramifying in the central inner plexiform layer were tuned to preferentially encode small stimuli. By contrast, ON cone bipolar cells with axons ramifying in the proximal inner plexiform layer, nearest the ganglion cell layer, were tuned to encode both small and large stimuli. This dichotomy in spatial tuning is attributable to amacrine cells providing stronger inhibition to central ON cone bipolar cells compared with proximal ON cone bipolar cells. Furthermore, background illumination altered this difference in spatial tuning. It became less pronounced in bright light, as amacrine cell-driven inhibition became pervasive among all ON cone bipolar cells. These results suggest that differential amacrine cell input determined the distinct spatial encoding properties among ON cone bipolar cells. These findings enhance the known parallel processing capacity of the retina. PMID:26203104

Exact-solution for cone-plate viscometry

NASA Astrophysics Data System (ADS)

Giacomin, A. J.; Gilbert, P. H.

2017-11-01

The viscosity of a Newtonian fluid is often measured by confining the fluid to the gap between a rotating cone that is perpendicular to a fixed disk. We call this experiment cone-plate viscometry. When the cone angle approaches π/2 , the viscometer gap is called narrow. The shear stress in the fluid, throughout a narrow gap, hardly departs from the shear stress exerted on the plate, and we thus call cone-plate flow nearly homogeneous. In this paper, we derive an exact solution for this slight heterogeneity, and from this, we derive the correction factors for the shear rate on the cone and plate, for the torque, and thus, for the measured Newtonian viscosity. These factors thus allow the cone-plate viscometer to be used more accurately, and with cone-angles well below π/2 . We find cone-plate flow field heterogeneity to be far slighter than previously thought. We next use our exact solution for the velocity to arrive at the exact solution for the temperature rise, due to viscous dissipation, in cone-plate flow subject to isothermal boundaries. Since Newtonian viscosity is a strong function of temperature, we expect our new exact solution for the temperature rise be useful to those measuring Newtonian viscosity, and especially so, to those using wide gaps. We include two worked examples to teach practitioners how to use our main results.

The spectral sensitivity of the human short-wavelength sensitive cones derived from thresholds and color matches.

PubMed

Stockman, A; Sharpe, L T; Fach, C

1999-08-01

We used two methods to estimate short-wave (S) cone spectral sensitivity. Firstly, we measured S-cone thresholds centrally and peripherally in five trichromats, and in three blue-cone monochromats, who lack functioning middle-wave (M) and long-wave (L) cones. Secondly, we analyzed standard color-matching data. Both methods yielded equivalent results, on the basis of which we propose new S-cone spectral sensitivity functions. At short and middle-wavelengths, our measurements are consistent with the color matching data of Stiles and Burch (1955, Optica Acta, 2, 168-181; 1959, Optica Acta, 6, 1-26), and other psychophysically measured functions, such as pi 3 (Stiles, 1953, Coloquio sobre problemas opticos de la vision, 1, 65-103). At longer wavelengths, S-cone sensitivity has previously been over-estimated.

Factors influencing the effective spray cone angle of pressure-swirl atomizers

NASA Astrophysics Data System (ADS)

Chen, S. K.; Lefebvre, A. H.; Rollbuhler, J.

1992-01-01

The spray cone angles produced by several simplex pressure-swirl nozzles are examined using three liquids whose viscosities range from 0.001 to 0.012 kg/ms (1 to 12 cp). Measurements of both the visible spray cone angle and the effective spray cone angle are carried out over wide ranges of injection pressure and for five different values of the discharge orifice length/diameter ratio. The influence of the number of swirl chamber feed slots on spray cone angle is also examined. The results show that the spray cone angle widens with increase in injection pressure but is reduced by increases in liquid viscosity and/or discharge orifice length/diameter ratio. Variation in the number of swirl chamber feed slots between one and three has little effect on the effective spray cone angle.

Mouse cones require an arrestin for normal inactivation of phototransduction.

PubMed

Nikonov, Sergei S; Brown, Bruce M; Davis, Jason A; Zuniga, Freddi I; Bragin, Alvina; Pugh, Edward N; Craft, Cheryl M

2008-08-14

Arrestins are proteins that arrest the activity of G protein-coupled receptors (GPCRs). While it is well established that normal inactivation of photoexcited rhodopsin, the GPCR of rod phototransduction, requires arrestin (Arr1), it has been controversial whether the same requirement holds for cone opsin inactivation. Mouse cone photoreceptors express two distinct visual arrestins: Arr1 and Arr4. By means of recordings from cones of mice with one or both arrestins knocked out, this investigation establishes that a visual arrestin is required for normal cone inactivation. Arrestin-independent inactivation is 70-fold more rapid in cones than in rods, however. Dual arrestin expression in cones could be a holdover from ancient genome duplication events that led to multiple isoforms of arrestin, allowing evolutionary specialization of one form while the other maintains the basic function.

Light adaptation alters the source of inhibition to the mouse retinal OFF pathway

PubMed Central

Mazade, Reece E.

2013-01-01

Sensory systems must avoid saturation to encode a wide range of stimulus intensities. One way the retina accomplishes this is by using both dim-light-sensing rod and bright-light-sensing cone photoreceptor circuits. OFF cone bipolar cells are a key point in this process, as they receive both excitatory input from cones and inhibitory input from AII amacrine cells via the rod pathway. However, in addition to AII amacrine cell input, other inhibitory inputs from cone pathways also modulate OFF cone bipolar cell light signals. It is unknown how these inhibitory inputs to OFF cone bipolar cells change when switching between rod and cone pathways or whether all OFF cone bipolar cells receive rod pathway input. We found that one group of OFF cone bipolar cells (types 1, 2, and 4) receive rod-mediated inhibitory inputs that likely come from the rod-AII amacrine cell pathway, while another group of OFF cone bipolar cells (type 3) do not. In both cases, dark-adapted rod-dominant light responses showed a significant contribution of glycinergic inhibition, which decreased with light adaptation and was, surprisingly, compensated by an increase in GABAergic inhibition. As GABAergic input has distinct timing and spatial spread from glycinergic input, a shift from glycinergic to GABAergic inhibition could significantly alter OFF cone bipolar cell signaling to downstream OFF ganglion cells. Larger GABAergic input could reflect an adjustment of OFF bipolar cell spatial inhibition, which may be one mechanism that contributes to retinal spatial sensitivity in the light. PMID:23926034

Chromatic detection from cone photoreceptors to V1 neurons to behavior in rhesus monkeys

PubMed Central

Hass, Charles A.; Angueyra, Juan M.; Lindbloom-Brown, Zachary; Rieke, Fred; Horwitz, Gregory D.

2015-01-01

Chromatic sensitivity cannot exceed limits set by noise in the cone photoreceptors. To determine how close neurophysiological and psychophysical chromatic sensitivity come to these limits, we developed a parameter-free model of stimulus encoding in the cone outer segments, and we compared the sensitivity of the model to the psychophysical sensitivity of monkeys performing a detection task and to the sensitivity of individual V1 neurons. Modeled cones had a temporal impulse response and a noise power spectrum that were derived from in vitro recordings of macaque cones, and V1 recordings were made during performance of the detection task. The sensitivity of the simulated cone mosaic, the V1 neurons, and the monkeys were tightly yoked for low-spatiotemporal-frequency isoluminant modulations, indicating high-fidelity signal transmission for this class of stimuli. Under the conditions of our experiments and the assumptions for our model, the signal-to-noise ratio for these stimuli dropped by a factor of ∼3 between the cones and perception. Populations of weakly correlated V1 neurons narrowly exceeded the monkeys' chromatic sensitivity but fell well short of the cones' chromatic sensitivity, suggesting that most of the behavior-limiting noise lies between the cone outer segments and the output of V1. The sensitivity gap between the cones and behavior for achromatic stimuli was larger than for chromatic stimuli, indicating greater postreceptoral noise. The cone mosaic model provides a means to compare visual sensitivity across disparate stimuli and to identify sources of noise that limit visual sensitivity. PMID:26523737

Chromatic detection from cone photoreceptors to V1 neurons to behavior in rhesus monkeys.

PubMed

Hass, Charles A; Angueyra, Juan M; Lindbloom-Brown, Zachary; Rieke, Fred; Horwitz, Gregory D

2015-01-01

Chromatic sensitivity cannot exceed limits set by noise in the cone photoreceptors. To determine how close neurophysiological and psychophysical chromatic sensitivity come to these limits, we developed a parameter-free model of stimulus encoding in the cone outer segments, and we compared the sensitivity of the model to the psychophysical sensitivity of monkeys performing a detection task and to the sensitivity of individual V1 neurons. Modeled cones had a temporal impulse response and a noise power spectrum that were derived from in vitro recordings of macaque cones, and V1 recordings were made during performance of the detection task. The sensitivity of the simulated cone mosaic, the V1 neurons, and the monkeys were tightly yoked for low-spatiotemporal-frequency isoluminant modulations, indicating high-fidelity signal transmission for this class of stimuli. Under the conditions of our experiments and the assumptions for our model, the signal-to-noise ratio for these stimuli dropped by a factor of ∼3 between the cones and perception. Populations of weakly correlated V1 neurons narrowly exceeded the monkeys' chromatic sensitivity but fell well short of the cones' chromatic sensitivity, suggesting that most of the behavior-limiting noise lies between the cone outer segments and the output of V1. The sensitivity gap between the cones and behavior for achromatic stimuli was larger than for chromatic stimuli, indicating greater postreceptoral noise. The cone mosaic model provides a means to compare visual sensitivity across disparate stimuli and to identify sources of noise that limit visual sensitivity.

Assessing Photoreceptor Structure in Retinitis Pigmentosa and Usher Syndrome.

PubMed

Sun, Lynn W; Johnson, Ryan D; Langlo, Christopher S; Cooper, Robert F; Razeen, Moataz M; Russillo, Madia C; Dubra, Alfredo; Connor, Thomas B; Han, Dennis P; Pennesi, Mark E; Kay, Christine N; Weinberg, David V; Stepien, Kimberly E; Carroll, Joseph

2016-05-01

The purpose of this study was to examine cone photoreceptor structure in retinitis pigmentosa (RP) and Usher syndrome using confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). Nineteen subjects (11 RP, 8 Usher syndrome) underwent ophthalmic and genetic testing, spectral-domain optical coherence tomography (SD-OCT), and AOSLO imaging. Split-detector images obtained in 11 subjects (7 RP, 4 Usher syndrome) were used to assess remnant cone structure in areas of altered cone reflectivity on confocal AOSLO. Despite normal interdigitation zone and ellipsoid zone appearance on OCT, foveal and parafoveal cone densities derived from confocal AOSLO images were significantly lower in Usher syndrome compared with RP. This was due in large part to an increased prevalence of non-waveguiding cones in the Usher syndrome retina. Although significantly correlated to best-corrected visual acuity and foveal sensitivity, cone density can decrease by nearly 38% before visual acuity becomes abnormal. Aberrantly waveguiding cones were noted within the transition zone of all eyes and corresponded to intact inner segment structures. These remnant cones decreased in density and increased in diameter across the transition zone and disappeared with external limiting membrane collapse. Foveal cone density can be decreased in RP and Usher syndrome before visible changes on OCT or a decline in visual function. Thus, AOSLO imaging may allow more sensitive monitoring of disease than current methods. However, confocal AOSLO is limited by dependence on cone waveguiding, whereas split-detector AOSLO offers unambiguous and quantifiable visualization of remnant cone inner segment structure. Confocal and split-detector thus offer complementary insights into retinal pathology.

Assessing Photoreceptor Structure in Retinitis Pigmentosa and Usher Syndrome

PubMed Central

Sun, Lynn W.; Johnson, Ryan D.; Langlo, Christopher S.; Cooper, Robert F.; Razeen, Moataz M.; Russillo, Madia C.; Dubra, Alfredo; Connor, Thomas B.; Han, Dennis P.; Pennesi, Mark E.; Kay, Christine N.; Weinberg, David V.; Stepien, Kimberly E.; Carroll, Joseph

2016-01-01

Purpose The purpose of this study was to examine cone photoreceptor structure in retinitis pigmentosa (RP) and Usher syndrome using confocal and nonconfocal split-detector adaptive optics scanning light ophthalmoscopy (AOSLO). Methods Nineteen subjects (11 RP, 8 Usher syndrome) underwent ophthalmic and genetic testing, spectral-domain optical coherence tomography (SD-OCT), and AOSLO imaging. Split-detector images obtained in 11 subjects (7 RP, 4 Usher syndrome) were used to assess remnant cone structure in areas of altered cone reflectivity on confocal AOSLO. Results Despite normal interdigitation zone and ellipsoid zone appearance on OCT, foveal and parafoveal cone densities derived from confocal AOSLO images were significantly lower in Usher syndrome compared with RP. This was due in large part to an increased prevalence of non-waveguiding cones in the Usher syndrome retina. Although significantly correlated to best-corrected visual acuity and foveal sensitivity, cone density can decrease by nearly 38% before visual acuity becomes abnormal. Aberrantly waveguiding cones were noted within the transition zone of all eyes and corresponded to intact inner segment structures. These remnant cones decreased in density and increased in diameter across the transition zone and disappeared with external limiting membrane collapse. Conclusions Foveal cone density can be decreased in RP and Usher syndrome before visible changes on OCT or a decline in visual function. Thus, AOSLO imaging may allow more sensitive monitoring of disease than current methods. However, confocal AOSLO is limited by dependence on cone waveguiding, whereas split-detector AOSLO offers unambiguous and quantifiable visualization of remnant cone inner segment structure. Confocal and split-detector thus offer complementary insights into retinal pathology. PMID:27145477

CNGA3 deficiency affects cone synaptic terminal structure and function and leads to secondary rod dysfunction and degeneration.

PubMed

Xu, Jianhua; Morris, Lynsie M; Michalakis, Stylianos; Biel, Martin; Fliesler, Steven J; Sherry, David M; Ding, Xi-Qin

2012-03-01

To investigate rod function and survival after cone dysfunction and degeneration in a mouse model of cone cyclic nucleotide-gated (CNG) channel deficiency. Rod function and survival in mice with cone CNG channel subunit CNGA3 deficiency (CNGA3-/- mice) were evaluated by electroretinographic (ERG), morphometric, and Western blot analyses. The arrangement, integrity, and ultrastructure of photoreceptor terminals were investigated by immunohistochemistry and electron microscopy. The authors found loss of cone function and cone death accompanied by impairment of rods and rod-driven signaling in CNGA3-/- mice. Scotopic ERG b-wave amplitudes were reduced by 15% at 1 month, 30% at 6 months, and 40% at 9 months and older, while scotopic a-wave amplitudes were decreased by 20% at 9 months, compared with ERGs of age-matched wild-type mice. Outer nuclear layer thickness in CNGA3-/- retina was reduced by 15% at 12 months compared with age-matched wild-type controls. This was accompanied by a 30%-40% reduction in expression of rod-specific proteins, including rhodopsin, rod transducin α-subunit, and glutamic acid-rich protein (GARP). Cone terminals in the CNGA3-/- retina showed a progressive loss of neurochemical and ultrastructural integrity. Abnormalities were observed as early as 1 month. Disorganized rod terminal ultrastructure was noted by 12 months. These findings demonstrate secondary rod impairment and degeneration after cone degeneration in mice with cone CNG channel deficiency. Loss of cone phototransduction accompanies the compromised integrity of cone terminals. With time, rod synaptic structure, function, and viability also become compromised.

An acoustic method for predicting relative strengths of cohesive sediment deposits

NASA Astrophysics Data System (ADS)

Reed, A. H.; Sanders, W. M.

2017-12-01

Cohesive sediment dynamics are fundamentally determined by sediment mineralogy, organic matter composition, ionic strength of water, and currents. These factors work to bind the cohesive sediments and to determine depositional rates. Once deposited the sediments exhibit a nonlinear response to stress and they develop increases in shear strength. Shear strength is critically important in resuspension, transport, creep, and failure predictions. Typically, shear strength is determined by point measurements, both indirectly from free-fall penetrometers or directly on cores with a shear vane. These values are then used to interpolate over larger areas. However, the remote determination of these properties would provide continuos coverage, yet it has proven difficult with sonar systems. Recently, findings from an acoustic study on cohesive sediments in a laboratory setting suggests that cohesive sediments may be differentiated using parametric acoustics; this method pulses two primary frequencies into the sediment and the resultant difference frequency is used to determine the degree of acoustic nonlinearity within the sediment. In this study, two marine clay species, kaolinite and montmorillonite, and two biopolymers, guar gum and xanthan gum were mixed to make nine different samples. The samples were evaluated in a parametric acoustic measurement tank. From the parametric acoustic measurements, the quadratic nonlinearity coefficient (beta) was determined. beta was correlated with the cation exchange capacity (CEC), an indicator of shear strength. The results indicate that increased acoustic nonlinearity correlates with increased CEC. From this work, laboratory measurements indicate that this correlation may be used evaluate geotechnical properties of cohesive sediments and may provide a means to predict sediment weakness in subaqueous environments.

Aerodynamic characteristics of the standard dynamics model in coning motion at Mach 0.6

NASA Technical Reports Server (NTRS)

Jermey, C.; Schiff, L. B.

1985-01-01

A wind tunnel test was conducted on the Standard Dynamics Model (a simplified generic fighter aircraft shape) undergoing coning motion at Mach 0.6. Six component force and moment data are presented for a range of angle of attack, sideslip, and coning rates. At the relatively low non-dimensional coning rate employed (omega b/2V less than or equal to 0.04), the lateral aerodynamic characteristics generally show a linear variation with coning rate.

Theory of chromatic noise masking applied to testing linearity of S-cone detection mechanisms.

PubMed

Giulianini, Franco; Eskew, Rhea T

2007-09-01

A method for testing the linearity of cone combination of chromatic detection mechanisms is applied to S-cone detection. This approach uses the concept of mechanism noise, the noise as seen by a postreceptoral neural mechanism, to represent the effects of superposing chromatic noise components in elevating thresholds and leads to a parameter-free prediction for a linear mechanism. The method also provides a test for the presence of multiple linear detectors and off-axis looking. No evidence for multiple linear mechanisms was found when using either S-cone increment or decrement tests. The results for both S-cone test polarities demonstrate that these mechanisms combine their cone inputs nonlinearly.

Variable Mach number design approach for a parallel waverider with a wide-speed range based on the osculating cone theory

NASA Astrophysics Data System (ADS)

Zhao, Zhen-tao; Huang, Wei; Li, Shi-Bin; Zhang, Tian-Tian; Yan, Li

2018-06-01

In the current study, a variable Mach number waverider design approach has been proposed based on the osculating cone theory. The design Mach number of the osculating cone constant Mach number waverider with the same volumetric efficiency of the osculating cone variable Mach number waverider has been determined by writing a program for calculating the volumetric efficiencies of waveriders. The CFD approach has been utilized to verify the effectiveness of the proposed approach. At the same time, through the comparative analysis of the aerodynamic performance, the performance advantage of the osculating cone variable Mach number waverider is studied. The obtained results show that the osculating cone variable Mach number waverider owns higher lift-to-drag ratio throughout the flight profile when compared with the osculating cone constant Mach number waverider, and it has superior low-speed aerodynamic performance while maintaining nearly the same high-speed aerodynamic performance.

Semi-automated identification of cones in the human retina using circle Hough transform

PubMed Central

Bukowska, Danuta M.; Chew, Avenell L.; Huynh, Emily; Kashani, Irwin; Wan, Sue Ling; Wan, Pak Ming; Chen, Fred K

2015-01-01

A large number of human retinal diseases are characterized by a progressive loss of cones, the photoreceptors critical for visual acuity and color perception. Adaptive Optics (AO) imaging presents a potential method to study these cells in vivo. However, AO imaging in ophthalmology is a relatively new phenomenon and quantitative analysis of these images remains difficult and tedious using manual methods. This paper illustrates a novel semi-automated quantitative technique enabling registration of AO images to macular landmarks, cone counting and its radius quantification at specified distances from the foveal center. The new cone counting approach employs the circle Hough transform (cHT) and is compared to automated counting methods, as well as arbitrated manual cone identification. We explore the impact of varying the circle detection parameter on the validity of cHT cone counting and discuss the potential role of using this algorithm in detecting both cones and rods separately. PMID:26713186

Bright and durable field emission source derived from refractory taylor cones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirsch, Gregory

A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tipmore » end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.« less

Enhanced dense attosecond electron bunch generation by irradiating an intense laser on a cone target

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Li-Xiang; Yu, Tong-Pu, E-mail: tongpu@nudt.edu.cn; Shao, Fu-Qiu

By using two-dimensional particle-in-cell simulations, we demonstrate enhanced spatially periodic attosecond electron bunches generation with an average density of about 10n{sub c} and cut-off energy up to 380 MeV. These bunches are acquired from the interaction of an ultra-short ultra-intense laser pulse with a cone target. The laser oscillating field pulls out the cone surface electrons periodically and accelerates them forward via laser pondermotive force. The inner cone wall can effectively guide these bunches and lead to their stable propagation in the cone, resulting in overdense energetic attosecond electron generation. We also consider the influence of laser and cone target parametersmore » on the bunch properties. It indicates that the attosecond electron bunch acceleration and propagation could be significantly enhanced without evident divergency by attaching a plasma capillary to the original cone tip.« less

The Verriest Lecture: Short-wave-sensitive cone pathways across the life span

PubMed Central

Werner, John S.

2017-01-01

Structurally and functionally, the short-wave-sensitive (S) cone pathways are thought to decline more rapidly with normal aging than the middle- and long-wave-sensitive cone pathways. This would explain the celebrated results by Verriest and others demonstrating that the largest age-related color discrimination losses occur for stimuli on a tritan axis. Here, we challenge convention, arguing from psychophysical data that selective S-cone pathway losses do not cause declines in color discrimination. We show substantial declines in chromatic detection and discrimination, as well as in temporal and spatial vision tasks, that are mediated by S-cone pathways. These functional losses are not, however, unique to S-cone pathways. Finally, despite reduced photon capture by S cones, their postreceptoral pathways provide robust signals for the visual system to renormalize itself to maintain nearly stable color perception across the life span. PMID:26974914

How the pine seeds attach to/detach from the pine cone scale?

PubMed

Song, Kahye; Chang, Shyr-Shea; Lee, Sang Joon

2017-01-01

One of the primary purposes of pine cones is the protection and distant dispersal of pine seeds. Pine cones open and release their embedded seeds on dry and windy days for long-distance dispersal. In this study, how the pine seed attach to/ detach from the pine cone scale for efficient seed dispersal were experimentally investigated by using X-ray micro-imaging technique. The cone and seeds adhere to one another in the presence of water, which could be explained by the surface tension and the contact angle hysteresis. Otherwise, without water, the waterproof seed wing surface permits rapid drying for detach and dispersion. On the other hand, during wildfires, pine cones open their seed racks and detach the pine seeds from pine cones for rapid seed dispersal. Due to these structural advantages, pine seeds are released safely and efficiently on adjust condition. These advantageous structure could be mimicked in practical applications.

Grating acuity at different luminances in wild-type mice and in mice lacking rod or cone function.

PubMed

Schmucker, Christine; Seeliger, Mathias; Humphries, Pete; Biel, Martin; Schaeffel, Frank

2005-01-01

The mouse eye has become an important model in vision research. However, it is not known how visual acuity changes with luminance. Therefore, grating acuity of mice was measured at different luminances in an automated optomotor paradigm. Furthermore, mutant mice lacking either rods (RHO-/- and CNGB1-/-) or cones (CNGA3-/-), or both, were studied to determine the rod and cone contribution to visual acuity. Freely ranging individual mice were automatically tracked at a 25-Hz sampling rate with a self-programmed video system in a large rotating optomotor drum. The drum had a square-wave grating inside with adjustable spatial frequency. The angular speed of the mice with respect to the center of the drum and the angular orientation of the snout-tail body axis were analyzed. In addition, the motor activity of the wild-type mice was recorded at different luminances. The optomotor drum provided reliable data on visual input to the mouse's behavior and was convenient to use, since the experimenter's had only to place the mice individually in a Perspex cylinder. Optomotor grating acuity of the wild-type mice was limited to 0.3 to 0.4 cyc/deg. Maximum optomotor responses were obtained at 0.1 to 0.2 cyc/deg. The importance of visual input declined monotonically with decreasing luminance (30 cd/m2, 100%; 0.1 cd/m2, 76.4%; 0.005 cd/m2, 45.9%; and darkness, -9%). Mice lacking functional rods were able to resolve gratings up to 0.1 cyc/deg at 30 cd/m2. Surprisingly, mice lacking functional cones had an optomotor acuity that was similar to the wild-type. Double-knockout mice without rods and cones had no detectable grating acuity. Because the visual system of the mouse is more responsive at bright luminances, experiments in which visual input is important should be performed in photopic conditions (30 cd/m2 or even more). Apparently, spatial vision is governed by the rod system, which is not saturated in the mesopic or low photopic range. Mice lacking both rods and cones have no detectable grating acuity, indicating that the retinal melanopsin system does not contribute to spatial vision.

Reconstructing an Explosive Basaltic Eruption in the Pinacate Volcanic Field, NW Sonora, Mexico

NASA Astrophysics Data System (ADS)

Zawacki, E. E.; Clarke, A. B.; Arrowsmith, R.; Lynch, D. J.

2017-12-01

Tephra deposits from explosive volcanic eruptions provide a means to reconstruct eruption characteristics, such as column height and erupted volume. Parameters like these are essential in assessing the explosivity of past eruptions and associated volcanic hazards. We applied such methods to a basaltic tephra deposit from one of the youngest eruptions in the Pinacate volcanic field (NW Sonora, Mexico). This roughly circular tephra blanket extends 13 km E-W and 13 km N-S, and covers an area of at least 135 km2. The source vent of this eruption is hypothesized to be the Tecolote volcano (lat 31.877, long -113.362), which is dated to 27 ± 6 ka (40Ar/39Ar). Fifty-three pits were dug across the extent of the tephra deposit to measure its thickness, record stratigraphy, characterize grain size distribution, and determine maximum clast size. Isopleth and isopach maps were created from these data to determine the column height (>9 km), estimate mass eruption rate (>2.1x106 kg/s), and calculate the erupted volume (>4.2x10-2 km3). Stratigraphic descriptions support two distinct episodes of tephra production. Unit A is dispersed in an approximately circular pattern ( 6.5 km radius) with its center shifted to the east of the vent. The distribution of Unit B is oblate ( 9.5 km major axis, 4.5 km minor axis) and trends to the southeast of the vent. Lava samples were collected from each of the seven Tecolote flows for XRF and ICP-MS geochemical analyses. These samples were compared to geochemical signatures from a Tecolote bomb, tephra from Units A and B, and cinder from the La Laja cone, which is the youngest dated cone in the field at 12 ± 4 ka (40Ar/39Ar). The La Laja sample is geochemically distinct from all Tecolote samples, confirming that it did not contribute to the two tephra units. Tephra from Unit A and Unit B have distinct signatures and fit within the geochemical evolution of the Tecolote lavas, supporting two explosive episodes from the Tecolote volcano, which has two cones. To provide a stronger age constraint on the eruption, samples for optically stimulated luminescence (OSL) dating were collected from the sandy silt unit below the tephra in two pits. Data for these dates are being analyzed.

An economical storage precipitation gage

Treesearch

Raymond D. Ratliff; Jack N. Reppert

1965-01-01

Describes how to make an economical "can-cone"-type storage precipitation gage, based on one originally designed by the California Department of Water Resources. The cone was modified by including an inner skirt to prevent loss of water between the cone and can. Periodic records of precipitation are obtained by stick measurement. Five complete cones cost $120...

Performance of the coned-face end seal with regard to energy conservation

NASA Technical Reports Server (NTRS)

Sehnal, J.; Sedy, J.; Zobens, A.; Etsion, I.

1982-01-01

The effects of face coning on seal performance are evaluated with particular regard to the energy saving potential of convex conedface end seals as indicated by torque reduction. Experiments were conducted using a conventional carbon flat-face pusher-type seal, a coned-face pusher-type seal, coned-face bellows-type seal, and a modified coned-face pusher-type seal intended for dynamically unstable operation, with shaft rotation at up to 8000 rpm, pressures of up to 2758 kPa, and a petroleum-based turbine oil as lubricant. Torque at the seal interface is found to be reduced by 42% when the standard flat-face seal is replaced by a coned seal, although the leakage of the cone-face seal was 11 times greater. Reduction of seal balance from 76.1 to 51.3% resulted in an additional 44% reduction in torque, although at the expense of excessive leakage, but did not produce unstable operation. Face temperatures were reduced by 33-56 C and wear was also reduced greatly on the cone face seals. Seal performance is noted to be in agreement with analytical calculations.

EML1 (CNG-Modulin) Controls Light Sensitivity in Darkness and under Continuous Illumination in Zebrafish Retinal Cone Photoreceptors

PubMed Central

Mehta, Milap; Tserentsoodol, Nomingerel; Postlethwait, John H.; Rebrik, Tatiana I.

2013-01-01

The ligand sensitivity of cGMP-gated (CNG) ion channels in cone photoreceptors is modulated by CNG-modulin, a Ca2+-binding protein. We investigated the functional role of CNG-modulin in phototransduction in vivo in morpholino-mediated gene knockdown zebrafish. Through comparative genomic analysis, we identified the orthologue gene of CNG-modulin in zebrafish, eml1, an ancient gene present in the genome of all vertebrates sequenced to date. We compare the photoresponses of wild-type cones with those of cones that do not express the EML1 protein. In the absence of EML1, dark-adapted cones are ∼5.3-fold more light sensitive than wild-type cones. Previous qualitative studies in several nonmammalian species have shown that immediately after the onset of continuous illumination, cones are less light sensitive than in darkness, but sensitivity then recovers over the following 15–20 s. We characterize light sensitivity recovery in continuously illuminated wild-type zebrafish cones and demonstrate that sensitivity recovery does not occur in the absence of EML1. PMID:24198367

EML1 (CNG-modulin) controls light sensitivity in darkness and under continuous illumination in zebrafish retinal cone photoreceptors.

PubMed

Korenbrot, Juan I; Mehta, Milap; Tserentsoodol, Nomingerel; Postlethwait, John H; Rebrik, Tatiana I

2013-11-06

The ligand sensitivity of cGMP-gated (CNG) ion channels in cone photoreceptors is modulated by CNG-modulin, a Ca(2+)-binding protein. We investigated the functional role of CNG-modulin in phototransduction in vivo in morpholino-mediated gene knockdown zebrafish. Through comparative genomic analysis, we identified the orthologue gene of CNG-modulin in zebrafish, eml1, an ancient gene present in the genome of all vertebrates sequenced to date. We compare the photoresponses of wild-type cones with those of cones that do not express the EML1 protein. In the absence of EML1, dark-adapted cones are ∼5.3-fold more light sensitive than wild-type cones. Previous qualitative studies in several nonmammalian species have shown that immediately after the onset of continuous illumination, cones are less light sensitive than in darkness, but sensitivity then recovers over the following 15-20 s. We characterize light sensitivity recovery in continuously illuminated wild-type zebrafish cones and demonstrate that sensitivity recovery does not occur in the absence of EML1.

[CHENG DAN-AN's contribution to direct moxibustion with moxa cone in Chinese Acupuncture and Moxibustion].

PubMed

Zhou, Pan; Wang, Ling-Ling; Zhang, Jian-Bin

2014-04-01

In the book of Chinese Acupuncture and Moxibustion by CHENG Dan-an, direct moxibustion with moxa cone was regarded as a classic style of moxibustion because of its innate character of heat induced thermal stimulus and burn toxin. CHENG Dan-an made the quantity of moxibustion more controllable through the selection of moxa wool, the size and number of moxa cones, and the tightness of moxa cones, etc. CHENG Dan-an 's clinical experience is summarized through treating stubborn and infectious diseases with direct moxibustion with moxa cone. The results showed that only with understanding the characteristics of moxibustion and key pathological mechanism of suitable disease could direct moxibustion with moxa cone and the appropriate methods be performed correctly. CHENG Dan-an confirmed the clinical effect of treating stubborn and intectious diseases with direct contact moxibustion with moxa cone, and optimized the specific operation scheme of direct moxibustion with moxa cone. It tell us that we should deeply study on moxibustion, to make it wide spread in the hereafter, bring benefit to mankind.

Dirac cones in isogonal hexagonal metallic structures

NASA Astrophysics Data System (ADS)

Wang, Kang

2018-03-01

A honeycomb hexagonal metallic lattice is equivalent to a triangular atomic one and cannot create Dirac cones in its electromagnetic wave spectrum. We study in this work the low-frequency electromagnetic band structures in isogonal hexagonal metallic lattices that are directly related to the honeycomb one and show that such structures can create Dirac cones. The band formation can be described by a tight-binding model that allows investigating, in terms of correlations between local resonance modes, the condition for the Dirac cones and the consequence of the third structure tile sustaining an extra resonance mode in the unit cell that induces band shifts and thus nonlinear deformation of the Dirac cones following the wave vectors departing from the Dirac points. We show further that, under structure deformation, the deformations of the Dirac cones result from two different correlation mechanisms, both reinforced by the lattice's metallic nature, which directly affects the resonance mode correlations. The isogonal structures provide new degrees of freedom for tuning the Dirac cones, allowing adjustment of the cone shape by modulating the structure tiles at the local scale without modifying the lattice periodicity and symmetry.

Comparison of four stable numerical methods for Abel's integral equation

NASA Technical Reports Server (NTRS)

Murio, Diego A.; Mejia, Carlos E.

1991-01-01

The 3-D image reconstruction from cone-beam projections in computerized tomography leads naturally, in the case of radial symmetry, to the study of Abel-type integral equations. If the experimental information is obtained from measured data, on a discrete set of points, special methods are needed in order to restore continuity with respect to the data. A new combined Regularized-Adjoint-Conjugate Gradient algorithm, together with two different implementations of the Mollification Method (one based on a data filtering technique and the other on the mollification of the kernal function) and a regularization by truncation method (initially proposed for 2-D ray sample schemes and more recently extended to 3-D cone-beam image reconstruction) are extensively tested and compared for accuracy and numerical stability as functions of the level of noise in the data.

Passively-coupled, low-coherence interferometric duct profiling with an astigmatism-corrected conical mirror.

PubMed

Ford, Helen D; Tatam, Ralph P

2017-04-17

Duct-profiling in test samples up to 25 mm in diameter has been demonstrated using a passive, low-coherence probe head with a depth resolution of 7.8 μm, incorporating an optical-fibre-linked conical mirror addressed by a custom-built array of single-mode fibres. Zemax modelling, and experimental assessment of instrument performance, show that degradation of focus, resulting from astigmatism introduced by the conical mirror, is mitigated by the introduction of a novel lens element. This enables a good beam focus to be achieved at distances of tens of millimetres from the cone axis, not achievable when the cone is used alone. Incorporation of the additional lens element is shown to provide a four-fold improvement in lateral imaging resolution, when compared with reflection from the conical mirror alone.

Infrared emission in Seyfert 2 galaxies - Reprocessed radiation from a dusty torus?

NASA Technical Reports Server (NTRS)

Storchi-Bergmann, Thaisa; Mulchaey, John S.; Wilson, Andrew S.

1992-01-01

New and existing data for a sample of nine Seyfert 2 galaxies with known 'ionization cones' are combined in order to test whether collimation results from shadowing of radiation from a small isotropic nuclear source by a thick dusty torus. The number of ionizing photons emitted by the compact nucleus is calculated from the emission-line ratios measured for gas within the cones. On the assumption that this compact nuclear source radiates isotropically, the optical-UV power incident on the torus, which is expected to be reradiated in the IR, is determined. It is found that the observed IRAS luminosities are consistent with the torus model in eight of the nine objects with sufficient data to perform the calculation. It is concluded that the data are generally consistent with collimation and reradiation by a dusty torus.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hastings, Matthew B

We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, themore » behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.« less

Resonances observed on mother-daughter rocket flights in the ionosphere. [signal frequency enhancement in auroral zones

NASA Technical Reports Server (NTRS)

Folkestad, K.; Troeim, J.

1973-01-01

Resonance phenomena have been observed in swept frequency experiments carried out on two mother-daughter Nike-Tomahawk rocket flights at auroral latitudes. The experimental method is briefly described and characteristic samples of the results are presented. A possible interpretation of some main resonances is offered, involving cold plasma cone resonances.

Aerodynamic flail for a spinning projectile

DOEpatents

Cole, James K.

1990-05-01

A flail is provided which reduces the spin of a projectile in a recovery system which includes a parachute, a cable connected to the parachute, a swivel, and means for connecting the swivel to the projectile. The flail includes a plurality of flexible filaments and a rotor for attaching the filaments to the front end of the projectile. The rotor is located radially with respect to the spinning axis of the projectile. In one embodiment, the projectile includes a first nose cone section housing a deployable spin damping assembly; a second nose cone section, housing a deployable parachute assembly; a shell section, supporting the first and second nose cone sections during flight of the projectile; a mechanism for releasing the first nose cone section from the second cone section; and a mechanism for releasing the second nose cone section from the shell section. In operation of this embodiment, the deployable spin damping assembly deploys during flight of the projectile when the mechanism for releasing the first nose cone section from the second nose cone section are actuated. Then, upon actuation of the mechanism for releasing the second nose cone section from the shell section, two things happen: the spin damping assembly separates from the projectile; and the deployable parachute assembly is deployed.

Aerodynamic flail for a spinning projectile

DOEpatents

Cole, James K.

1990-01-01

A flail is provided which reduces the spin of a projectile in a recovery system which includes a parachute, a cable connected to the parachute, a swivel, and means for connecting the swivel to the projectile. The flail includes a plurality of flexible filaments and a rotor for attaching the filaments to the front end of the projectile. The rotor is located radially with respect to the spinning axis of the projectile. In one embodiment, the projectile includes a first nose cone section housing a deployable spin damping assembly; a second nose cone section, housing a deployable parachute assembly; a shell section, supporting the first and second nose cone sections during flight of the projectile; a mechanism for releasing the first nose cone section from the second cone section; and a mechanism for releasing the second nose cone section from the shell section. In operation of this embodiment, the deployable spin damping assembly deploys during flight of the projectile when the mechanism for releasing the first nose cone section from the second nose cone section are actuated. Then, upon actuation of the mechanism for releasing the second nose cone section from the shell section, two things happen: the spin damping assembly separates from the projectile; and the deployable parachute assembly is deployed.

Methods for investigating the local spatial anisotropy and the preferred orientation of cones in adaptive optics retinal images

PubMed Central

Cooper, Robert F.; Lombardo, Marco; Carroll, Joseph; Sloan, Kenneth R.; Lombardo, Giuseppe

2016-01-01

The ability to non-invasively image the cone photoreceptor mosaic holds significant potential as a diagnostic for retinal disease. Central to the realization of this potential is the development of sensitive metrics for characterizing the organization of the mosaic. Here we evaluated previously-described (Pum et al., 1990) and newly-developed (Fourier- and Radon-based) methods of measuring cone orientation in both simulated and real images of the parafoveal cone mosaic. The proposed algorithms correlated well across both simulated and real mosaics, suggesting that each algorithm would provide an accurate description of individual photoreceptor orientation. Despite the high agreement between algorithms, each performed differently in response to image intensity variation and cone coordinate jitter. The integration property of the Fourier transform allowed the Fourier-based method to be resistant to cone coordinate jitter and perform the most robustly of all three algorithms. Conversely, when there is good image quality but unreliable cone identification, the Radon algorithm performed best. Finally, in cases where both the image and cone coordinate reliability was excellent, the method of Pum et al. (1990) performed best. These descriptors are complementary to conventional descriptive metrics of the cone mosaic, such as cell density and spacing, and have the potential to aid in the detection of photoreceptor pathology. PMID:27484961

Accumulation of actin in subsets of pioneer growth cone filopodia in response to neural and epithelial guidance cues in situ

PubMed Central

1993-01-01

Directed outgrowth of neural processes must involve transmission of signals from the tips of filopodia to the central region of the growth cone. Here, we report on the distribution and dynamics of one possible element in this process, actin, in live growth cones which are reorienting in response to in situ guidance cues. In grasshopper embryonic limbs, pioneer growth cones respond to at least three types of guidance cues: a limb axis cue, intermediate target cells, and a circumferential band of epithelial cells. With time-lapse imaging of intracellularly injected rhodamine-phalloidin and rhodamine-actin, we monitored the distribution of actin during growth cone responses to these cues. In distal limb regions, accumulation of actin in filopodia and growth cone branches accompanies continued growth, while reduction of actin accompanies withdrawal. Where growth cones are reorienting to intermediate target cells, or along the circumferential epithelial band, actin selectively accumulates in the proximal regions of those filopodia that have contacted target cells or are extending along the band. Actin accumulations can be retrogradely transported along filopodia, and can extend into the central region of the growth cone. These results suggest that regulation and translocation of actin may be a significant element in growth cone steering. PMID:8227150

Advances in Valveless Piezoelectric Pump with Cone-shaped Tubes

NASA Astrophysics Data System (ADS)

Zhang, Jian-Hui; Wang, Ying; Huang, Jun

2017-07-01

This paper reviews the development of valveless piezoelectric pump with cone-shaped tube chronologically, which have widely potential application in biomedicine and micro-electro-mechanical systems because of its novel principles and deduces the research direction in the future. Firstly, the history of valveless piezoelectric pumps with cone-shaped tubes is reviewed and these pumps are classified into the following types: single pump with solid structure or plane structure, and combined pump with parallel structure or series structure. Furthermore, the function of each type of cone-shaped tubes and pump structures are analyzed, and new directions of potential expansion of valveless piezoelectric pumps with cone-shaped tubes are summarized and deduced. The historical argument, which is provided by the literatures, that for a valveless piezoelectric pump with cone-shaped tubes, cone angle determines the flow resistance and the flow resistance determines the flow direction. The argument is discussed in the reviewed pumps one by one, and proved to be convincing. Finally, it is deduced that bionics is pivotal in the development of valveless piezoelectric pump with cone-shaped tubes from the perspective of evolution of biological structure. This paper summarizes the current valveless piezoelectric pumps with cone-shaped tubes and points out the future development, which may provide guidance for the research of piezoelectric actuators.

Determination of CME 3D parameters based on a new full ice-cream cone model

NASA Astrophysics Data System (ADS)

Na, Hyeonock; Moon, Yong-Jae

2017-08-01

In space weather forecast, it is important to determine three-dimensional properties of CMEs. Using 29 limb CMEs, we examine which cone type is close to a CME three-dimensional structure. We find that most CMEs have near full ice-cream cone structure which is a symmetrical circular cone combined with a hemisphere. We develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model). In addition, we derive CME mean density (ρmean=Mtotal/Vcone) based on the full ice-cream cone structure. For several limb events, we determine CME mass by applying the Solarsoft procedure (e.g., cme_mass.pro) to SOHO/LASCO C3 images. CME volumes are estimated from the full ice-cream cone structure. From the power-law relationship between CME mean density and its height, we estimate CME mean densities at 20 solar radii (Rs). We will compare the CME densities at 20 Rs with their corresponding ICME densities.

Chemical Chaperone TUDCA Preserves Cone Photoreceptors in a Mouse Model of Leber Congenital Amaurosis

PubMed Central

Zhang, Tao; Baehr, Wolfgang; Fu, Yingbin

2012-01-01

Purpose. Mutations in either retinoid isomerase (RPE65) or lecithin-retinol acyltransferase (LRAT) lead to Leber congenital amaurosis (LCA). By using the Lrat–/– mouse model, previous studies have shown that the rapid cone degeneration in LCA was caused by endoplasmic reticulum (ER) stress induced by S-opsin aggregation. The purpose of this study is to examine the efficacy of an ER chemical chaperone, tauroursodeoxycholic acid (TUDCA), in preserving cones in the Lrat–/– model. Methods. Lrat–/– mice were systemically administered with TUDCA and vehicle (0.15 M NaHCO3) every 3 days from P9 to P28. Cone cell survival was determined by counting cone cells on flat-mounted retinas. The expression and subcellular localization of cone-specific proteins were analyzed by western blotting and immunohistochemistry, respectively. Results. TUDCA treatment reduced ER stress and apoptosis in Lrat–/– retina. It significantly slowed down cone degeneration in Lrat–/– mice, resulting in a ∼3-fold increase in cone density in the ventral and central retina as compared with the vehicle-treated mice at P28. Furthermore, TUDCA promoted the degradation of cone membrane–associated proteins by enhancing the ER-associated protein degradation pathway. Conclusions. Systemic injection of TUDCA is effective in reducing ER stress, preventing apoptosis, and preserving cones in Lrat–/– mice. TUDCA has the potential to lead to the development of a new class of therapeutic drugs for treating LCA. PMID:22531707

Visual Cone Arrestin 4 Contributes to Visual Function and Cone Health.

PubMed

Deming, Janise D; Pak, Joseph S; Brown, Bruce M; Kim, Moon K; Aung, Moe H; Eom, Yun Sung; Shin, Jung-A; Lee, Eun-Jin; Pardue, Machelle T; Craft, Cheryl Mae

2015-08-01

Visual arrestins (ARR) play a critical role in shutoff of rod and cone phototransduction. When electrophysiological responses are measured for a single mouse cone photoreceptor, ARR1 expression can substitute for ARR4 in cone pigment desensitization; however, each arrestin may also contribute its own, unique role to modulate other cellular functions. A combination of ERG, optokinetic tracking, immunohistochemistry, and immunoblot analysis was used to investigate the retinal phenotypes of Arr4 null mice (Arr4-/-) compared with age-matched control, wild-type mice. When 2-month-old Arr4-/- mice were compared with wild-type mice, they had diminished visual acuity and contrast sensitivity, yet enhanced ERG flicker response and higher photopic ERG b-wave amplitudes. In contrast, in older Arr4-/- mice, all ERG amplitudes were significantly reduced in magnitude compared with age-matched controls. Furthermore, in older Arr4-/- mice, the total cone numbers decreased and cone opsin protein immunoreactive expression levels were significantly reduced, while overall photoreceptor outer nuclear layer thickness was unchanged. Our study demonstrates that Arr4-/- mice display distinct phenotypic differences when compared to controls, suggesting that ARR4 modulates essential functions in high acuity vision and downstream cellular signaling pathways that are not fulfilled or substituted by the coexpression of ARR1, despite its high expression levels in all mouse cones. Without normal ARR4 expression levels, cones slowly degenerate with increasing age, making this a new model to study age-related cone dystrophy.

Peripheral detection and resolution with mid-/long-wavelength and short-wavelength sensitive cone systems.

PubMed

Zhu, Hai-Feng; Zele, Andrew J; Suheimat, Marwan; Lambert, Andrew J; Atchison, David A

2016-08-01

This study compared neural resolution and detection limits of the human mid-/long-wavelength and short-wavelength cone systems with anatomical estimates of photoreceptor and retinal ganglion cell spacings and sizes. Detection and resolution limits were measured from central fixation out to 35° eccentricity across the horizontal visual field using a modified Lotmar interferometer. The mid-/long-wavelength cone system was studied using a green (550 nm) test stimulus to which S-cones have low sensitivity. To bias resolution and detection to the short-wavelength cone system, a blue (450 nm) test stimulus was presented against a bright yellow background that desensitized the M- and L-cones. Participants were three trichromatic males with normal visual functions. With green stimuli, resolution showed a steep central-peripheral gradient that was similar between participants, whereas the detection gradient was shallower and patterns were different between participants. Detection and resolution with blue stimuli were poorer than for green stimuli. The detection of blue stimuli was superior to resolution across the horizontal visual field and the patterns were different between participants. The mid-/long-wavelength cone system's resolution is limited by midget ganglion cell spacing and its detection is limited by the size of the M- and L-cone photoreceptors, consistent with previous observations. We found that no such simple relationships occur for the short-wavelength cone system between resolution and the bistratified ganglion cell spacing, nor between detection and the S-cone photoreceptor sizes.

Comparison of Cone Model Parameters for Halo Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Na, Hyeonock; Moon, Y.-J.; Jang, Soojeong; Lee, Kyoung-Sun; Kim, Hae-Yeon

2013-11-01

Halo coronal mass ejections (HCMEs) are a major cause of geomagnetic storms, hence their three-dimensional structures are important for space weather. We compare three cone models: an elliptical-cone model, an ice-cream-cone model, and an asymmetric-cone model. These models allow us to determine three-dimensional parameters of HCMEs such as radial speed, angular width, and the angle [ γ] between sky plane and cone axis. We compare these parameters obtained from three models using 62 HCMEs observed by SOHO/LASCO from 2001 to 2002. Then we obtain the root-mean-square (RMS) error between the highest measured projection speeds and their calculated projection speeds from the cone models. As a result, we find that the radial speeds obtained from the models are well correlated with one another ( R > 0.8). The correlation coefficients between angular widths range from 0.1 to 0.48 and those between γ-values range from -0.08 to 0.47, which is much smaller than expected. The reason may be the different assumptions and methods. The RMS errors between the highest measured projection speeds and the highest estimated projection speeds of the elliptical-cone model, the ice-cream-cone model, and the asymmetric-cone model are 376 km s-1, 169 km s-1, and 152 km s-1. We obtain the correlation coefficients between the location from the models and the flare location ( R > 0.45). Finally, we discuss strengths and weaknesses of these models in terms of space-weather application.

Efficacy of chemical sterilization and storage conditions of gutta-percha cones.

PubMed

da Motta, P G; de Figueiredo, C B; Maltos, S M; Nicoli, J R; Ribeiro Sobrinho, A P; Maltos, K L; Carvalhais, H P

2001-09-01

The objective of the present study was to assess the efficacy of 2.5% sodium hypochlorite and 2.2% glutaraldehyde ('Cidex') as sterilizing agents for gutta-percha cones. The efficacy of storage of gutta-percha cones in the presence or absence of paraformaldehyde was also evaluated. Gutta-percha cones artificially contaminated with a suspension of Bacillus stearothermophilus (ATCC/7953) were treated with either 2.2% glutaraldehyde for 10, 15, 30 and 60 min and 10 and 12 h, or 2.5% sodium hypochlorite for 5, 10 and 15 min. The cones were then incubated in thioglycollate medium for the determination of microbial growth. In parallel, additional sterile gutta-percha cones were stored in sealed containers with or without paraformaldehyde tablets for 30 days. The containers were opened 30 min a day and exposed to the environment of a functioning dental clinic. Twelve cones were removed weekly from the containers to determine whether contamination had occurred. The results showed that 2.5% sodium hypochlorite was effective after 5, 10 and 15 min, whereas 10 and 12 h contact with 2.2% glutaraldehyde was necessary to obtain sterilization. There was no contamination of the gutta-percha cones when stored with or without paraformaldehyde. Sodium hypochlorite (2.5%) and 2.2% glutaraldehyde ('Cidex') proved to be effective as sterilizing agents for gutta-percha cones, with sodium hypochlorite requiring shorter periods of use. No difference was observed between the two methods of cone storage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

G.A. Valentine; F.V. Perry; D. Krier

Five Pleistocene basaltic volcanoes in Crater Flat (southern Nevada) demonstrate the complexity of eruption processes associated with small-volume basalts and the effects of initial emplacement characteristics on post-eruptive geomorphic evolution of the volcanic surfaces. The volcanoes record eruptive processes in their pyroclastic facies ranging from ''classical'' Strombolian mechanisms to, potentially, violent Strombolian mechanisms. Cone growth was accompanied, and sometimes disrupted, by effusion of lavas from the bases of cones. Pyroclastic cones were built upon a gently southward-sloping surface and were prone to failure of their down-slope (southern) flanks. Early lavas flowed primarily southward and, at Red and Black Cone volcanoes,more » carried abundant rafts of cone material on the tops of the flows. These resulting early lava fields eventually built platforms such that later flows erupted from the eastern (at Red Cone) and northern (at Black Cone) bases of the cones. Three major surface features--scoria cones, lava fields with abundant rafts of pyroclastic material, and lava fields with little or no pyroclastic material--experienced different post-eruptive surficial processes. Contrary to previous interpretations, we argue that the Pleistocene Crater Flat volcanoes are monogenetic, each having formed in a single eruptive episode lasting months to a few years, and with all eruptive products having emanated from the area of the volcanoes main cones rather than from scattered vents. Geochemical variations within the volcanoes must be interpreted within a monogenetic framework, which implies preservation of magma source heterogeneities through ascent and eruption of the magmas.« less

CREW TRAINING - APOLLO XVI

NASA Image and Video Library

1972-03-02

S72-30694 (28 Jan. 1972) --- Astronauts John W. Young, left, Apollo 16 commander, and Charles M. Duke Jr., lunar module pilot, prepare to begin a simulated traverse in a training area at the Kennedy Space Center (KSC). The fifth National Aeronautics and Space Administration (NASA) Apollo lunar landing mission is scheduled to land in the mountainous highlands region near the crater Descartes to explore the area for a three-day period. Among the experiments to fly on Apollo 16 is the soil mechanics (S-200) experiment or self-recording penetrometer, a model of which is held here by Duke. A training model of the Lunar Roving Vehicle (LRV) is parked between the two crew men. Astronaut Thomas K. (Ken) Mattingly II is prime crew command module pilot for the mission.

Calcium Homeostasis and Cone Signaling Are Regulated by Interactions between Calcium Stores and Plasma Membrane Ion Channels

PubMed Central

Bartoletti, Theodore M.; Huang, Wei; Akopian, Abram; Thoreson, Wallace B.; Krizaj, David

2009-01-01

Calcium is a messenger ion that controls all aspects of cone photoreceptor function, including synaptic release. The dynamic range of the cone output extends beyond the activation threshold for voltage-operated calcium entry, suggesting another calcium influx mechanism operates in cones hyperpolarized by light. We have used optical imaging and whole-cell voltage clamp to measure the contribution of store-operated Ca2+ entry (SOCE) to Ca2+ homeostasis and its role in regulation of neurotransmission at cone synapses. Mn2+ quenching of Fura-2 revealed sustained divalent cation entry in hyperpolarized cones. Ca2+ influx into cone inner segments was potentiated by hyperpolarization, facilitated by depletion of intracellular Ca2+ stores, unaffected by pharmacological manipulation of voltage-operated or cyclic nucleotide-gated Ca2+ channels and suppressed by lanthanides, 2-APB, MRS 1845 and SKF 96365. However, cation influx through store-operated channels crossed the threshold for activation of voltage-operated Ca2+ entry in a subset of cones, indicating that the operating range of inner segment signals is set by interactions between store- and voltage-operated Ca2+ channels. Exposure to MRS 1845 resulted in ∼40% reduction of light-evoked postsynaptic currents in photopic horizontal cells without affecting the light responses or voltage-operated Ca2+ currents in simultaneously recorded cones. The spatial pattern of store-operated calcium entry in cones matched immunolocalization of the store-operated sensor STIM1. These findings show that store-operated channels regulate spatial and temporal properties of Ca2+ homeostasis in vertebrate cones and demonstrate their role in generation of sustained excitatory signals across the first retinal synapse. PMID:19696927

S cones: Evolution, retinal distribution, development, and spectral sensitivity.

PubMed

Hunt, David M; Peichl, Leo

2014-03-01

S cones expressing the short wavelength-sensitive type 1 (SWS1) class of visual pigment generally form only a minority type of cone photoreceptor within the vertebrate duplex retina. Hence, their primary role is in color vision, not in high acuity vision. In mammals, S cones may be present as a constant fraction of the cones across the retina, may be restricted to certain regions of the retina or may form a gradient across the retina, and in some species, there is coexpression of SWS1 and the long wavelength-sensitive (LWS) class of pigment in many cones. During retinal development, SWS1 opsin expression generally precedes that of LWS opsin, and evidence from genetic studies indicates that the S cone pathway may be the default pathway for cone development. With the notable exception of the cartilaginous fishes, where S cones appear to be absent, they are present in representative species from all other vertebrate classes. S cone loss is not, however, uncommon; they are absent from most aquatic mammals and from some but not all nocturnal terrestrial species. The peak spectral sensitivity of S cones depends on the spectral characteristics of the pigment present. Evidence from the study of agnathans and teleost fishes indicates that the ancestral vertebrate SWS1 pigment was ultraviolet (UV) sensitive with a peak around 360 nm, but this has shifted into the violet region of the spectrum (>380 nm) on many separate occasions during vertebrate evolution. In all cases, the shift was generated by just one or a few replacements in tuning-relevant residues. Only in the avian lineage has tuning moved in the opposite direction, with the reinvention of UV-sensitive pigments.

The growth and erosion of cinder cones in Guatemala and El Salvador: Models and statistics

NASA Astrophysics Data System (ADS)

Bemis, Karen; Walker, Jim; Borgia, Andrea; Turrin, Brent; Neri, Marco; Swisher, Carl, III

2011-04-01

Morphologic data for 147 cinder cones in southern Guatemala and western El Salvador are compared with data from the San Francisco volcanic field, Arizona (USA), Cima volcanic field, California (USA), Michoácan-Guanajuato volcanic field, Mexico, and the Lamongan volcanic field, East Java. The Guatemala cones have an average height of 110 +/- 50 m, an average basal diameter of 660 +/- 230 m and an average top diameter of 180 +/- 150 m. The general morphology of these cones can be described by their average cone angle of slope (24 +/- 7), average height-to-radius ratio (0.33 +/- 0.09) and their flatness (0.24 +/- 0.18). Although the mean values for the Guatemalan cones are similar to those for other volcanic fields (e.g., San Francisco volcanic field, Arizona; Cima volcanic field, California; Michoácan-Guanajuato volcanic field, Mexico; and Lamongan volcanic field, East Java), the range of morphologies encompasses almost all of those observed worldwide for cinder cones. Three new 40Ar/ 39Ar age dates are combined with 19 previously published dates for cones in Guatemala and El Salvador. There is no indication that the morphologies of these cones have changed over the last 500-1000 ka. Furthermore, a re-analysis of published data for other volcanic fields suggests that only in the Cima volcanic field (of those studied) is there clear evidence of degradation with age. Preliminary results of a numerical model of cinder cone growth are used to show that the range of morphologies observed in the Guatemalan cinder cones could all be primary, that is, due to processes occurring at the time of eruption.

Relationships between tree size, crown shape, gender segregation and sex allocation in Pinus halepensis, a Mediterranean pine tree.

PubMed

Ne'eman, Gidi; Goubitz, Shirrinka; Werger, Marinus J A; Shmida, Avi

2011-07-01

Sex allocation has been studied mainly in small herbaceous plants but much less in monoecious wind-pollinated trees. The aim of this study was to explore changes in gender segregation and sex allocation by Pinus halepensis, a Mediterranean lowland pine tree, within tree crowns and between trees differing in their size or crown shape. The production of new male and female cones and sex allocation of biomass, nitrogen and phosphorus were studied. The relationship between branch location, its reproductive status and proxies of branch vigour was also studied. Small trees produced only female cones, but, as trees grew, they produced both male and female cones. Female cones were produced mainly in the upper part of the crown, and male cones in its middle and lower parts. Lateral branch density was correlated with the number of male but not female cones; lateral branches were more dense in large than in small trees and even denser in hemispherical trees. Apical branches grew faster, were thicker and their phosphorus concentration was higher than in lateral shoots. Nitrogen concentration was higher in cone-bearing apical branches than in apical vegetative branches and in lateral branches with or without cones. Allocation to male relative to female function increased with tree size as predicted by sex allocation theory. The adaptive values of sex allocation and gender segregation patterns in P. halepensis, in relation to its unique life history, are demonstrated and discussed. Small trees produce only female cones that have a higher probability of being pollinated than the probability of male cones pollinating; the female-first strategy enhances population spread. Hemispherical old trees are loaded with serotinous cones that supply enough seeds for post-fire germination; thus, allocation to males is more beneficial than to females.

Agreement in Cone Density Derived from Gaze-Directed Single Images Versus Wide-Field Montage Using Adaptive Optics Flood Illumination Ophthalmoscopy

PubMed Central

Chew, Avenell L.; Sampson, Danuta M.; Kashani, Irwin; Chen, Fred K.

2017-01-01

Purpose We compared cone density measurements derived from the center of gaze-directed single images with reconstructed wide-field montages using the rtx1 adaptive optics (AO) retinal camera. Methods A total of 29 eyes from 29 healthy subjects were imaged with the rtx1 camera. Of 20 overlapping AO images acquired, 12 (at 3.2°, 5°, and 7°) were used for calculating gaze-directed cone densities. Wide-field AO montages were reconstructed and cone densities were measured at the corresponding 12 loci as determined by field projection relative to the foveal center aligned to the foveal dip on optical coherence tomography. Limits of agreement in cone density measurement between single AO images and wide-field AO montages were calculated. Results Cone density measurements failed in 1 or more gaze directions or retinal loci in up to 58% and 33% of the subjects using single AO images or wide-field AO montage, respectively. Although there were no significant overall differences between cone densities derived from single AO images and wide-field AO montages at any of the 12 gazes and locations (P = 0.01–0.65), the limits of agreement between the two methods ranged from as narrow as −2200 to +2600, to as wide as −4200 to +3800 cones/mm2. Conclusions Cone density measurement using the rtx1 AO camera is feasible using both methods. Local variation in image quality and altered visibility of cones after generating montages may contribute to the discrepancies. Translational Relevance Cone densities from single AO images are not interchangeable with wide-field montage derived–measurements. PMID:29285417

CNGA3 Deficiency Affects Cone Synaptic Terminal Structure and Function and Leads to Secondary Rod Dysfunction and Degeneration

PubMed Central

Xu, Jianhua; Morris, Lynsie M.; Michalakis, Stylianos; Biel, Martin; Fliesler, Steven J.; Sherry, David M.

2012-01-01

Purpose. To investigate rod function and survival after cone dysfunction and degeneration in a mouse model of cone cyclic nucleotide-gated (CNG) channel deficiency. Methods. Rod function and survival in mice with cone CNG channel subunit CNGA3 deficiency (CNGA3−/− mice) were evaluated by electroretinographic (ERG), morphometric, and Western blot analyses. The arrangement, integrity, and ultrastructure of photoreceptor terminals were investigated by immunohistochemistry and electron microscopy. Results. The authors found loss of cone function and cone death accompanied by impairment of rods and rod-driven signaling in CNGA3−/− mice. Scotopic ERG b-wave amplitudes were reduced by 15% at 1 month, 30% at 6 months, and 40% at 9 months and older, while scotopic a-wave amplitudes were decreased by 20% at 9 months, compared with ERGs of age-matched wild-type mice. Outer nuclear layer thickness in CNGA3−/− retina was reduced by 15% at 12 months compared with age-matched wild-type controls. This was accompanied by a 30%–40% reduction in expression of rod-specific proteins, including rhodopsin, rod transducin α-subunit, and glutamic acid-rich protein (GARP). Cone terminals in the CNGA3−/− retina showed a progressive loss of neurochemical and ultrastructural integrity. Abnormalities were observed as early as 1 month. Disorganized rod terminal ultrastructure was noted by 12 months. Conclusions. These findings demonstrate secondary rod impairment and degeneration after cone degeneration in mice with cone CNG channel deficiency. Loss of cone phototransduction accompanies the compromised integrity of cone terminals. With time, rod synaptic structure, function, and viability also become compromised. PMID:22247469

Pre-dispersal predation effect on seed packaging strategies and seed viability.

PubMed

DeSoto, Lucía; Tutor, David; Torices, Rubén; Rodríguez-Echeverría, Susana; Nabais, Cristina

2016-01-01

An increased understanding of intraspecific seed packaging (i.e. seed size/number strategy) variation across different environments may improve current knowledge of the ecological forces that drive seed evolution in plants. In particular, pre-dispersal seed predation may influence seed packaging strategies, triggering a reduction of the resources allocated to undamaged seeds within the preyed fruits. Assessing plant reactions to pre-dispersal seed predation is crucial to a better understanding of predation effects, but the response of plants to arthropod attacks remains unexplored. We have assessed the effect of cone predation on the size and viability of undamaged seeds in populations of Juniperus thurifera with contrasting seed packaging strategies, namely, North African populations with single-large-seeded cones and South European populations with multi-small-seeded cones. Our results show that the incidence of predation was lower on the single-large-seeded African cones than on the multi-small-seeded European ones. Seeds from non-preyed cones were also larger and had a higher germination success than uneaten seeds from preyed cones, but only in populations with multi-seeded cones and in cones attacked by Trisetacus sp., suggesting a differential plastic response to predation. It is possible that pre-dispersal seed predation has been a strong selective pressure in European populations with high cone predation rates, being a process which maintains multi-small-seeded cones and empty seeds as a strategy to save some seeds from predation. Conversely, pre-dispersal predation might not have a strong effect in the African populations with single-large-seeded cones characterized by seed germination and filling rates higher than those in the European populations. Our results indicate that differences in pre-dispersal seed predators and predation levels may affect both selection on and intraspecific variation in seed packaging.

Understanding the cone scale in Cupressaceae: insights from seed-cone teratology in Glyptostrobus pensilis.

PubMed

Dörken, Veit Martin; Rudall, Paula J

2018-01-01

Both wild-type and teratological seed cones are described in the monoecious conifer Glyptostrobus pensilis and compared with those of other Cupressaceae sensu lato and other conifers. Some Cupressaceae apparently possess a proliferation of axillary structures in their cone scales. In our interpretation, in Glyptostrobus each bract of both typical and atypical seed cones bears two descending accessory shoots, interpreted here as seed scales (ovuliferous scales). The primary seed scale is fertile and forms the ovules, the second is sterile and forms characteristic tooth-like structures. The bract and the two axillary seed scales are each supplied with a single distinct vascular bundle that enters the cone axis as a separate strand; this vasculature also characterises the descending accessory short shoots in the vegetative parts of the crown. In wild-type seed cones, the fertile seed scale is reduced to its ovules, and the ovules are always axillary. In contrast, the ovules of some of the teratological seed cones examined were located at the centre of the cone scale. An additional tissue found on the upper surface of the sterile lower seed scale is here interpreted as the axis of the fertile seed scale. Thus, the central position of the ovules can be explained by recaulescent fusion of the upper fertile and lower sterile seed scales. In several teratological cone scales, the ovules were enveloped by an additional sterile tissue that is uniseriate and represents an epidermal outgrowth of the fertile seed scale. Close to the ovules, the epidermis was detached from lower tissue and surrounded the ovule completely, except at the micropyle. These teratological features are potentially significant in understanding seed-cone homologies among extant conifers.

Physical properties of new collimator cone system for stereotactic radiation therapy developed in samsung medical center.

PubMed

Kim, D Y; Ahn, Y C; Oh, D G; Choi, D R; Ju, S G; Yeo, I H; Huh, S J

2000-09-01

A new collimator cone system has been developed at the Samsung Medical Center that overcomes some of the limitations of present commercially supplied collimator cones. The physical properties of the newly developed cone system are described in this report. The new cones have relatively larger aperture sizes (3.0-7.0 cm in diameter) and are 16 cm in length. Each new cone is fabricated with cerrobend alloy melted and poured into a stainless steel housing that is permanently fixed to a mounting plate. The mounting plate of the new cone is designed to insert into the wedge mount slot of the gantry head. The mechanical accuracy of the central axis of the cone pointing to the isocenter was tested using film, a steel ball positioned at the isocenter by the mechanical isocenter device. For the evaluation of beam flatness and penumbra, off-axis ratios at 5 cm depth were measured by film dosimetry using polystyrene phantom. The average error of the mechanical isocenter was 0.27 mm (+/- 0.16 mm). The beam flatness was excellent in the central region of the beam, and the average penumbra width was 3.35 mm (+/- 0.25 mm). The new cone design has more clearance between the patient's head and the gantry, and can more easily be removed from the gantry head because it slides in and out of the wedge slot. This facilitates changing cone sizes during one treatment session, and makes the process of double exposure port films easier. A new collimator cone system for stereotactic radiation therapy has been developed. The mechanical accuracy and physical properties are satisfactory for clinical use, and the new design permits a wider range of clinical applications for stereotactic radiation therapy.

CT cardiac imaging: evolution from 2D to 3D backprojection

NASA Astrophysics Data System (ADS)

Tang, Xiangyang; Pan, Tinsu; Sasaki, Kosuke

2004-04-01

The state-of-the-art multiple detector-row CT, which usually employs fan beam reconstruction algorithms by approximating a cone beam geometry into a fan beam geometry, has been well recognized as an important modality for cardiac imaging. At present, the multiple detector-row CT is evolving into volumetric CT, in which cone beam reconstruction algorithms are needed to combat cone beam artifacts caused by large cone angle. An ECG-gated cardiac cone beam reconstruction algorithm based upon the so-called semi-CB geometry is implemented in this study. To get the highest temporal resolution, only the projection data corresponding to 180° plus the cone angle are row-wise rebinned into the semi-CB geometry for three-dimensional reconstruction. Data extrapolation is utilized to extend the z-coverage of the ECG-gated cardiac cone beam reconstruction algorithm approaching the edge of a CT detector. A helical body phantom is used to evaluate the ECG-gated cone beam reconstruction algorithm"s z-coverage and capability of suppressing cone beam artifacts. Furthermore, two sets of cardiac data scanned by a multiple detector-row CT scanner at 16 x 1.25 (mm) and normalized pitch 0.275 and 0.3 respectively are used to evaluate the ECG-gated CB reconstruction algorithm"s imaging performance. As a reference, the images reconstructed by a fan beam reconstruction algorithm for multiple detector-row CT are also presented. The qualitative evaluation shows that, the ECG-gated cone beam reconstruction algorithm outperforms its fan beam counterpart from the perspective of cone beam artifact suppression and z-coverage while the temporal resolution is well maintained. Consequently, the scan speed can be increased to reduce the contrast agent amount and injection time, improve the patient comfort and x-ray dose efficiency. Based up on the comparison, it is believed that, with the transition of multiple detector-row CT into volumetric CT, ECG-gated cone beam reconstruction algorithms will provide better image quality for CT cardiac applications.

Synaptic Ribbon Active Zones in Cone Photoreceptors Operate Independently from One Another

PubMed Central

Grassmeyer, Justin J.; Thoreson, Wallace B.

2017-01-01

Cone photoreceptors depolarize in darkness to release glutamate-laden synaptic vesicles. Essential to release is the synaptic ribbon, a structure that helps organize active zones by clustering vesicles near proteins that mediate exocytosis, including voltage-gated Ca2+ channels. Cone terminals have many ribbon-style active zones at which second-order neurons receive input. We asked whether there are functionally significant differences in local Ca2+ influx among ribbons in individual cones. We combined confocal Ca2+ imaging to measure Ca2+ influx at individual ribbons and patch clamp recordings to record whole-cell ICa in salamander cones. We found that the voltage for half-maximal activation (V50) of whole cell ICa in cones averaged −38.1 mV ± 3.05 mV (standard deviation [SD]), close to the cone membrane potential in darkness of ca. −40 mV. Ca2+ signals at individual ribbons varied in amplitude from one another and showed greater variability in V50 values than whole-cell ICa, suggesting that Ca2+ signals can differ significantly among ribbons within cones. After accounting for potential sources of technical variability in measurements of Ca2+ signals and for contributions from cone-to-cone differences in ICa, we found that the variability in V50 values for ribbon Ca2+ signals within individual cones showed a SD of 2.5 mV. Simulating local differences in Ca2+ channel activity at two ribbons by shifting the V50 value of ICa by ±2.5 mV (1 SD) about the mean suggests that when the membrane depolarizes to −40 mV, two ribbons could experience differences in Ca2+ influx of >45%. Further evidence that local Ca2+ changes at ribbons can be regulated independently was obtained in experiments showing that activation of inhibitory feedback from horizontal cells (HCs) to cones in paired recordings changed both amplitude and V50 of Ca2+ signals at individual ribbons. By varying the strength of synaptic output, differences in voltage dependence and amplitude of Ca2+ signals at individual ribbons shape the information transmitted from cones to downstream neurons in vision. PMID:28744203

An ex vivo comparison of three different gutta-percha cones when compacted at different temperatures: rheological considerations in relation to the filling of lateral canals.

PubMed

Venturi, M; Di Lenarda, R; Breschi, L

2006-08-01

To compare ex vivo the penetration of three brands of gutta-percha cones, compacted under a constant force and heated to different temperatures, into artificial lateral canals. Resin blocks with simulated main canals, each having two lateral canals (C at 6.5 and A at 13 mm from the surface of the resin block), were selected. A gutta-percha cone, either Mynol MF, Hygenic MF or GT Tulsa 0.04 was compacted into each main canal for 5 s using a wire rod with a diameter of 0.7 mm soldered to the bottom of a metal cylinder, with a force of 2.7 kg at controlled temperatures of 37, 42, 47, 52, 60 degrees C. The penetration of each brand of gutta-percha into 60 lateral canals (10 at each temperature) was measured using a stereomicroscope. Statistical analysis was performed using the ANOVA, the Scheffè test and the t-test. None of the three brands of cones entered up to 0.1 mm within either lateral canal until a temperature of 47 degrees C was reached; at that temperature only Mynol cones (P < or = 0.05) penetrated in four of 10 A-level canals (mean 0.13 +/- 0.19 mm) and in all 10 C-level canals (mean 0.43 +/- 0.12 mm). The A-level lateral canals were penetrated at 52 degrees C by Mynol cones (mean 0.76 +/- 0.34 mm) to a significantly greater distance (P < or = 0.05) than Tulsa cones (mean 0.31 +/- 0.12 mm) and Hygenic cones (mean 0.11 +/- 0.08 mm). At 60 degrees C the Mynol cones (mean 1.93 +/- 0.34 mm) penetrated significantly more (P < or = 0.05) than the Tulsa cones (mean 0.86 +/- 0.22 mm) and Hygenic cones (mean 0.67 +/- 0.19 mm). The C-level lateral canals were penetrated at 52 degrees C by Mynol cones (mean 0.91 +/- 0.29 mm) to a significantly greater distance (P < or = 0.05) than Tulsa cones (mean 0.47 +/- 0.16 mm) and Hygenic cones (mean 0.46 +/- 0.15 mm), whilst no significant difference was found at 60 degrees C. When heated and compacted, the three gutta-percha cones penetrated the lateral canals to different degrees. They penetrated more than 0.43 mm into the lateral canals only at temperatures higher than 47 degrees C.

Evaluation of the X-Linked High-Grade Myopia Locus (MYP1) with Cone Dysfunction and Color Vision Deficiencies

PubMed Central

Metlapally, Ravikanth; Michaelides, Michel; Bulusu, Anuradha; Li, Yi-Ju; Schwartz, Marianne; Rosenberg, Thomas; Hunt, David M.; Moore, Anthony T.; Züchner, Stephan; Rickman, Catherine Bowes; Young, Terri L.

2014-01-01

Purpose X-linked high myopia with mild cone dysfunction and color vision defects has been mapped to chromosome Xq28 (MYP1 locus). CXorf2/TEX28 is a nested, intercalated gene within the red-green opsin cone pigment gene tandem array on Xq28. The authors investigated whether TEX28 gene alterations were associated with the Xq28-linked myopia phenotype. Genomic DNA from five pedigrees (with high myopia and either protanopia or deuteranopia) that mapped to Xq28 were screened for TEX28 copy number variations (CNVs) and sequence variants. Methods To examine for CNVs, ultra-high resolution array-comparative genomic hybridization (array-CGH) assays were performed comparing the subject genomic DNA with control samples (two pairs from two pedigrees). Opsin or TEX28 gene-targeted quantitative real-time gene expression assays (comparative CT method) were performed to validate the array-CGH findings. All exons of TEX28, including intron/exon boundaries, were amplified and sequenced using standard techniques. Results Array-CGH findings revealed predicted duplications in affected patient samples. Although only three copies of TEX28 were previously reported within the opsin array, quantitative real-time analysis of the TEX28 targeted assay of affected male or carrier female individuals in these pedigrees revealed either fewer (one) or more (four or five) copies than did related and control unaffected individuals. Sequence analysis of TEX28 did not reveal any variants associated with the disease status. Conclusions CNVs have been proposed to play a role in disease inheritance and susceptibility as they affect gene dosage. TEX28 gene CNVs appear to be associated with the MYP1 X-linked myopia phenotypes. PMID:19098318

Efficiency of seed production in southern pine seed orchards

Treesearch

David L. Bramlett

1977-01-01

Seed production in southern pine seed orchards can be evaluated by estimating the efficiency of four separate stages of cone, seed, and seedling development. Calculated values are: cone efficiency (CE), the ratio of mature cones to the initial flower crop; seed efficiency (SE), the ratio of filled seeds per cone to the seed potential; extraction efficiency (EE), the...

Cone-Deciphered Modes of Problem Solving Action (MPSA Cone): Alternative Perspectives on Diversified Professions.

ERIC Educational Resources Information Center

Lai, Su-Huei

A conceptual framework of the modes of problem-solving action has been developed on the basis of a simple relationship cone to assist individuals in diversified professions in inquiry and implementation of theory and practice in their professional development. The conceptual framework is referred to as the Cone-Deciphered Modes of Problem Solving…

Influence of seed weight on early development of eastern white pine

Treesearch

M. E., Jr. Demeritt; H. W., Jr. Hocker

1975-01-01

In the Northeast, eastern white pine (Pinus strobus L.) cannot be relied upon to consistently regenerate naturally due to the destruction of the cone crops by the white pine cone beetle (Conopthorus coniperda Schwarz). The white pine cone beetle has been reported to have destroyed the white pine cone crops for nine consecutive...

Shatter cones - An outstanding problem in shock mechanics. [geological impact fracture surface in cratering

NASA Technical Reports Server (NTRS)

Milton, D. J.

1977-01-01

Shatter cone characteristics are surveyed. Shatter cones, a form of rock fracture in impact structures, apparently form as a shock front interacts with inhomogeneities or discontinuities in the rock. Topics discussed include morphology, conditions of formation, shock pressure of formation, and theories of formation. It is thought that shatter cones are produced within a limited range of shock pressures extending from about 20 to perhaps 250 kbar. Apical angles range from less than 70 deg to over 120 deg. Tentative hypotheses concerning the physical process of shock coning are considered. The range in shock pressures which produce shatter cones might correspond to the range in which shock waves decompose into elastic and deformational fronts.

An analysis of the static load test on single square pile of 40x40 cm2, using finite element method in Rusunawa project, Jatinegara, Jakarta

NASA Astrophysics Data System (ADS)

Harasid, Harun; Roesyanto; Iskandar, Rudi; Silalahi, Sofyan A.

2018-03-01

Piling Foundation is one of the foundations which is used to penetrate its load through soil layer. The power carried by the piling is obtained from the end bearing capacity, that is, the compressive end piling and friction bearing capacity obtained from friction bearing and adhesive capacity between the piling and the soil around it. The investigation on the Standard Penetration Test is aimed to get the description of soil layer, based on the type and color of soil through visual observation, and soil characteristics. SPT data can be used to calculate bearing capacity. Besides investigating the SPT, this study is also been equipped by taking the samples in laboratory and loading test on the piling and Ducth Cone Penetrometer (DCP) data to confirm its bearing capacity. This study analyzed bearing capacity and settlement in the square pile of 40X40 cm in diameter in a single pile or grouped, using an empirical method, AllPile program, Plaxis program, and comparing the result with interpreting its loading test in the foundation of Rusunawa project, Jatinegara, Jakarta. The analysis was been done by using the data on soil investigation and laboratory by comparing them with Mohr-Coulomb soil model. Ultimate bearing capacity from the SPT data in the piling of 15.4 meters was 189.81 tons and the parameter of soil shear strength was 198.67 tons. The sander point, based on Aoki and De Alencar bearing capacity was 276.241 tons and based on Mayerhoff it was 305.49 tons. Based on the loading test of bearing capacity, unlimited bearing capacity for the three methods was Davisson (260 tons), Mazurkiewich (270 tons), and Chin (250 tons). The efficiency of grouped piles according to Converse-Library Equation method = 0.73, according to Los Angeles Group Action Equation method = 0.59, and according to Sheila-Keeny method = 0.94. Bearing capacity based on piling strength was 221.76 tons, bearing capacity based on calendaring data was 201.71 tons, and lateral bearing capacity of a single piling foundation was 129.6 kN (12.96 tons). When the maximum load (280 tons) was been given, more decrease occurred in the Maintained load test of 21.00 mm and Quick Load Test method of 20.67 mm, compared with the result of Load Test in the field of 18.74 mm. Based on ASTM D1143/81, the permitted value was 25.40 mm. Therefore, based on that decreasing, it could be concluded that foundation piles were safe in the construction. The pore water pressure is highly influenced by time so that in Maintained Load Test and Quick Load Test, there was the disparity in the level of pore water pressure. Based on the result of the calculation, Quick Load Test showed that in pore water pressure was dissipated in its acceleration.

Hydrogeologic controls and geochemical indicators of groundwater movement in the Niles Cone and southern East Bay Plain groundwater subbasins, Alameda County, California

USGS Publications Warehouse

Teague, Nicholas F.; Izbicki, John A.; Borchers, Jim; Kulongoski, Justin T.; Jurgens, Bryant C.

2018-02-01

Beginning in the 1970s, Alameda County Water District began infiltrating imported water through ponds in repurposed gravel quarries at the Quarry Lakes Regional Park, in the Niles Cone groundwater subbasin, to recharge groundwater and to minimize intrusion of saline, San Francisco Bay water into freshwater aquifers. Hydraulic connection between distinct aquifers underlying Quarry Lakes allows water to recharge the upper aquifer system to depths of 400 feet below land surface, and the Deep aquifer to depths of more than 650 feet. Previous studies of the Niles Cone and southern East Bay Plain groundwater subbasins suggested that these two subbasins may be hydraulically connected. Characterization of storage capacities and hydraulic properties of the complex aquifers and the structural and stratigraphic controls on groundwater movement aids in optimal storage and recovery of recharged water and provides information on the ability of aquifers shared by different water management agencies to fulfill competing storage and extraction demands. The movement of recharge water through the Niles Cone groundwater subbasin from Quarry Lakes and the possible hydraulic connection between the Niles Cone and the southern East Bay Plain groundwater subbasins were investigated using interferometric synthetic aperture radar (InSAR), water-chemistry, and isotopic data, including tritium/helium-3, helium-4, and carbon-14 age-dating techniques.InSAR data collected during refilling of the Quarry Lakes recharge ponds show corresponding ground-surface displacement. Maximum uplift was about 0.8 inches, reasonable for elastic expansion of sedimentary materials experiencing an increase in hydraulic head that resulted from pond refilling. Sodium concentrations increase while calcium and magnesium concentrations in groundwater decrease along groundwater flowpaths from the Niles Cone groundwater subbasin through the Deep aquifer to the northwest toward the southern East Bay Plain groundwater subbasin. Residual effects of pre-1970s intrusion of saline water from San Francisco Bay, including high chloride concentrations in groundwater, are evident in parts of the Niles Cone subbasin. Noble gas recharge temperatures indicate two primary recharge sources (Quarry Lakes and Alameda Creek) in the Niles Cone groundwater subbasin. Although recharge at Quarry Lakes affects hydraulic heads as far as the transition zone between the Niles Cone and East Bay Plain groundwater subbasins (about 5 miles), the effect of recharged water on water quality is only apparent in wells near (less than 2 miles) recharge sources. Groundwater chemistry from upper aquifer system wells near Quarry Lakes showed an evaporated signal (less negative oxygen and hydrogen isotopic values) relative to surrounding groundwater and a tritium concentration (2 tritium units) consistent with recently recharged water from a surface-water impoundment.Uncorrected carbon-14 activities measured in water sampled from wells in the Niles Cone groundwater subbasin range from 16 to 100 percent modern carbon (pmC). The geochemical reaction modeling software NETPATH was used to interpret carbon-14 ages along a flowpath from Quarry Lakes toward the East Bay Plain groundwater subbasin. Model results indicate that changes in groundwater chemistry are controlled by cation exchange on clay minerals and weathering of primary silicate minerals. Old groundwater (lower carbon-14 activities) is characterized by high dissolved silica and pH. Interpreted carbon-14 ages ranged from 830 to more than 7,000 years before present and are less than helium-4 ages that range from 2,000 to greater than 11,000 years before present. The average horizontal groundwater velocity along the studied flowpath, as calculated using interpreted carbon-14 ages, through the Deep aquifer of the Niles Cone groundwater subbasin is between 3 and 12 feet per year. The groundwater velocity decreases near the boundary of the transition zone to the southern East Bay Plain groundwater subbasin to about 0.5 feet per year. These changes may result from water recharged from different sources converging in flowpaths north of the transition zone, or a boundary to flow between the Niles Cone and southern East Bay Plain groundwater subbasins, likely owing to changes in lithology caused by depositional patterns.

Geomorphology of the Trinity River floodplain in Dallas County, Texas

NASA Astrophysics Data System (ADS)

Haugen, B. D.; Roig-Silva, C.; Manning, A. R.; Harrelson, D. W.; Olsen, R. S.; Dunbar, J. P.; Pearson, M. L.

2010-12-01

Data from more than 1,800 geologic borings and over 500 cone penetrometer tests (CPTs) were used to characterize the geomorphology of the Trinity River floodplain in the Dallas Metropolitan Area. Historical maps, aerial photographs and other published information were used to prepare a preliminary geomorphic map. Boring logs and CPT data were then used to refine the preliminary map, produce a series of two-dimensional (2D) and three-dimensional (3D) cross sections, and interpret the recent geologic history of the area. Geomorphologic interpretations - most importantly the locations of paleo-channel deposits of sands and gravels - were used to identify reaches of the levees managed by the United States Army Corps of Engineers (USACE) and the City of Dallas that may be at significant risk for under-seepage. Boring logs and CPT data collected atop the levees were used to assess through-seepage risks. Local bedrock is comprised of cretaceous-age Eagle Ford Shale and Austin Chalk. Depth to bedrock in the study area averaged 14.6 m (47.8 ft). The uppermost surface of bedrock has been deeply incised by a meandering river. Vertical relief between the shallowest bedrock sections and deepest portion of the incised paleo-channel is more than 15 m (50 ft). In places the incised paleo-channel is more than 0.8 km (0.5 mi) wide. These data confirm the presence of an erosional unconformity between local bedrock and overlying quaternary floodplain deposits. The observed erosional unconformity is attributed to a higher-energy fluvial environment that occurred as a result of a drop in base level. Recent floodplain deposits consist of interlobate point bar, channel and overbank sediments that are generally distributed in a fining-upward sequence. Buried channel dimensions vary widely, but are more than 250 m (820 ft) in some areas - much larger than the current channel. A semi-continuous basal layer of quaternary sands and gravels approximately 2 to 5 m (7 to 16 ft) thick exists in much of the study area. These data indicate that the discharge rate of the Trinity River today is at its lowest since quaternary deposition began. Large terraces of varying geometry and elevation observed at the edge of the floodplain show that the Trinity River has been geographically constrained to its current floodplain since the late Cretaceous, and perhaps even earlier.

A compendium of P- and S-wave velocities from surface-to-borehole logging; summary and reanalysis of previously published data and analysis of unpublished data

USGS Publications Warehouse

Boore, David M.

2003-01-01

For over 28 years, the U.S. Geological Survey (USGS) has been acquiring seismic velocity and geologic data at a number of locations in California, many of which were chosen because strong ground motions from earthquakes were recorded at the sites. The method for all measurements involves picking first arrivals of P- and S-waves from a surface source recorded at various depths in a borehole (as opposed to noninvasive methods, such as the SASW method [e.g., Brown et al., 2002]). The results from most of the sites are contained in a series of U.S. Geological Survey Open-File Reports (see References). Until now, none of the results have been available as computer files, and before 1992 the interpretation of the arrival times was in terms of piecemeal interval velocities, with no attempt to derive a layered model that would fit the travel times in an overall sense (the one exception is Porcella, 1984). In this report I reanalyze all of the arrival times in terms of layered models for P- and for S-wave velocities at each site, and I provide the results as computer files. In addition to the measurements reported in the open-file reports, I also include some borehole results from other reports, as well as some results never before published. I include data for 277 boreholes (at the time of this writing; more will be added to the web site as they are obtained), all in California (I have data from boreholes in Washington and Utah, but these will be published separately). I am also in the process of interpreting travel time data obtained using a seismic cone penetrometer at hundreds of sites; these data can be interpreted in the same way of those obtained from surface-to-borehole logging. When available, the data will be added to the web site (see below for information on obtaining data from the World Wide Web (WWW)). In addition to the basic borehole data and results, I provide information concerning strong-motion stations that I judge to be close enough to the boreholes that the borehole velocity models can be used as the velocity models beneath the stations.

Analysis of recurring sinking events of armored tracked vehicles along dirt roads in the agricultural periphery of the Gaza Strip

NASA Astrophysics Data System (ADS)

Roskin, Joel

2013-04-01

The second (Al-Aqsa) intifada (Arab violent uprising) which erupted across Israel in 2000 eventually led the Israel Defense Forces to deploy armored tracked vehicles (ATVs) (tanks, armored personal carriers, and D-9 bulldozers) within Israel's agricultural periphery of the Gaza Strip, following daily attempts by Arab terrorists and guerillas to penetrate Israel. Combat movement of the ATVs was mainly concentrated to dirt roads, between agricultural fields, wherever possible. As a result of semi-arid Mediterranean (climate) winter rains, annually averaging 250 - 350 mm, it was reported that ATVs often sank in muddy terrain. This study investigated what caused ATVs to sink. The main data collected concerning the types of vehicles that sank related to: land-use characteristics, soil type, and daily rainfall. Interviews with commanders were also conducted for additional details. Between the fall and spring, surveys and weekly / bi-weekly field soil cone penetrometer tests were conducted at ten sites with different pedological and land-use characteristics. The loess soils, especially in agricultural fields, were generally found to be conducive to ATV traffic, even shortly after rainstorms of 10-30 mm. However, following several rainfall events exceeding 10 mm, ATVs and tanks regularly sank into local topographic depressions in the undulating landscape. These consisted of short segments of dirt roads where runoff and suspended sediment collected. After the early rains in late fall, tank ruts fossilize and become conduits of concentrated runoff and fine particles eroded by ATV activity during the summer months. Tank track ruts that formed in mud, compacted the soil, drastically altered drainage patterns by directing significant surface flow, and suspended sediment into these depressions, creating "tank-traps" whose trafficability ranged from "untrafficable" to "trafficable with constraints." This study shows that intense, routine, defensive military activity operated without any terrain and/or environmental analysis and monitoring can produce self-inflicted, environmental and combat problems. The cope of this work also demonstrates that it is vital to persistently promote and market the application of military geoscience products in order to save lives, limit expenses, and preserve the environment to a relative degree, often for the short and long-term benefit of both sides of a conflict.

Geologic investigation of Playa Lakes, Tonopah Test Range, Nevada : data report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rautman, Christopher Arthur

Subsurface geological investigations have been conducted at two large playa lakes at the Tonopah Test Range in central Nevada. These characterization activities were intended to provide basic stratigraphic-framework information regarding the lateral distribution of ''hard'' and ''soft'' sedimentary materials for use in defining suitable target regions for penetration testing. Both downhole geophysical measurements and macroscopic lithilogic descriptions were used as a surrogate for quantitative mechanical-strength properties, although some quantitative laboratory strength measurements were obtained as well. Both rotary (71) and core (19) holes on a systematic grid were drilled in the southern half of the Main Lake; drill hole spacingsmore » are 300 ft north-south and 500-ft east-west. The drilled region overlaps a previous cone-penetrometer survey that also addressed the distribution of hard and soft material. Holes were drilled to a depth of 40 ft and logged using both geologic examination and down-hole geophysical surveying. The data identify a large complex of very coarse-grained sediment (clasts up to 8 mm) with interbedded finer-grained sands, silts and clays, underlying a fairly uniform layer of silty clay 6 to 12 ft thick. Geophysical densities of the course-grained materials exceed 2.0 g/cm{sup 2}, and this petrophysical value appears to be a valid discriminator of hard vs. soft sediments in the subsurface. Thirty-four holes, including both core and rotary drilling, were drilled on a portion of the much larger Antelope Lake. A set of pre-drilling geophysical surveys, including time-domain electromagnetic methods, galvanic resistivity soundings, and terrain-conductivity surveying, was used to identify the gross distribution of conductive and resistive facies with respect to the present lake outline. Conductive areas were postulated to represent softer, clay-rich sediments with larger amounts of contained conductive ground water. Initial drilling, consisting of cored drill holes to 100-ft (33-m) depth, confirmed both the specific surface geophysical measurements and the more general geophysical model of the subsurface lake facies. Good agreement of conductive regions with drill holes containing little to no coarse-grained sediments was observed, and vice-versa. A second phase of grid drilling on approximately 300-ft (100-m) centers was targeted a delineating a region of sufficient size containing essentially no coarse-grained ''hard'' material. Such a region was identified in the southwestern portion of Antelope Lake.« less

Optimized x-ray source scanning trajectories for iterative reconstruction in high cone-angle tomography

NASA Astrophysics Data System (ADS)

Kingston, Andrew M.; Myers, Glenn R.; Latham, Shane J.; Li, Heyang; Veldkamp, Jan P.; Sheppard, Adrian P.

2016-10-01

With the GPU computing becoming main-stream, iterative tomographic reconstruction (IR) is becoming a com- putationally viable alternative to traditional single-shot analytical methods such as filtered back-projection. IR liberates one from the continuous X-ray source trajectories required for analytical reconstruction. We present a family of novel X-ray source trajectories for large-angle CBCT. These discrete (sparsely sampled) trajectories optimally fill the space of possible source locations by maximising the degree of mutually independent information. They satisfy a discrete equivalent of Tuy's sufficiency condition and allow high cone-angle (high-flux) tomog- raphy. The highly isotropic nature of the trajectory has several advantages: (1) The average source distance is approximately constant throughout the reconstruction volume, thus avoiding the differential-magnification artefacts that plague high cone-angle helical computed tomography; (2) Reduced streaking artifacts due to e.g. X-ray beam-hardening; (3) Misalignment and component motion manifests as blur in the tomogram rather than double-edges, which is easier to automatically correct; (4) An approximately shift-invariant point-spread-function which enables filtering as a pre-conditioner to speed IR convergence. We describe these space-filling trajectories and demonstrate their above-mentioned properties compared with a traditional helical trajectories.

Visual Cone Arrestin 4 Contributes to Visual Function and Cone Health

PubMed Central

Deming, Janise D.; Pak, Joseph S.; Brown, Bruce M.; Kim, Moon K.; Aung, Moe H.; Eom, Yun Sung; Shin, Jung-a; Lee, Eun-Jin; Pardue, Machelle T.; Craft, Cheryl Mae

2015-01-01

Purpose Visual arrestins (ARR) play a critical role in shutoff of rod and cone phototransduction. When electrophysiological responses are measured for a single mouse cone photoreceptor, ARR1 expression can substitute for ARR4 in cone pigment desensitization; however, each arrestin may also contribute its own, unique role to modulate other cellular functions. Methods A combination of ERG, optokinetic tracking, immunohistochemistry, and immunoblot analysis was used to investigate the retinal phenotypes of Arr4 null mice (Arr4−/−) compared with age-matched control, wild-type mice. Results When 2-month-old Arr4−/− mice were compared with wild-type mice, they had diminished visual acuity and contrast sensitivity, yet enhanced ERG flicker response and higher photopic ERG b-wave amplitudes. In contrast, in older Arr4−/− mice, all ERG amplitudes were significantly reduced in magnitude compared with age-matched controls. Furthermore, in older Arr4−/− mice, the total cone numbers decreased and cone opsin protein immunoreactive expression levels were significantly reduced, while overall photoreceptor outer nuclear layer thickness was unchanged. Conclusions Our study demonstrates that Arr4−/− mice display distinct phenotypic differences when compared to controls, suggesting that ARR4 modulates essential functions in high acuity vision and downstream cellular signaling pathways that are not fulfilled or substituted by the coexpression of ARR1, despite its high expression levels in all mouse cones. Without normal ARR4 expression levels, cones slowly degenerate with increasing age, making this a new model to study age-related cone dystrophy. PMID:26284544

The retina visual cycle is driven by cis retinol oxidation in the outer segments of cones

PubMed Central

Sato, Shinya; Frederiksen, Rikard; Cornwall, M. Carter; Kefalov, Vladimir J.

2017-01-01

Vertebrate rod and cone photoreceptors require continuous supply of chromophore for regenerating their visual pigments after photoactivation. Cones, which mediate our daytime vision, demand a particularly rapid supply of 11-cis retinal chromophore in order to maintain their function in bright light. An important contribution to this process is thought to be the chromophore precursor 11-cis retinol, which is supplied to cones from Müller cells in the retina and subsequently oxidized to 11-cis retinal as part of the retina visual cycle. However, the molecular identity of the cis retinol oxidase in cones remains unclear. Here, as a first step in characterizing this enzymatic reaction, we sought to determine the subcellular localization of this activity in salamander red cones. We found that the onset of dark adaptation of isolated salamander red cones was substantially faster when exposing directly their outer vs. their inner segment to 9-cis retinol, an analogue of 11-cis retinol. In contrast, this difference was not observed when treating the outer vs. inner segment with 9-cis retinal, a chromophore analogue which can directly support pigment regeneration. These results suggest, surprisingly, that the cis-retinol oxidation occurs in the outer segments of cone photoreceptors. Confirming this notion, pigment regeneration with exogenously added 9-cis retinol was directly observed in the truncated outer segments of cones, but not in rods. We conclude that the enzymatic machinery required for the oxidation of recycled cis retinol as part of the retina visual cycle is present in the outer segments of cones. PMID:28359344

Comparison of three-dimensional parameters of Halo CMEs using three cone models

NASA Astrophysics Data System (ADS)

Na, H.; Moon, Y.; Jang, S.; Lee, K.

2012-12-01

Halo coronal mass ejections (HCMEs) are a major cause of geomagnetic storms and their three dimensional structures are important for space weather. In this study, we compare three cone models: an elliptical cone model, an ice-cream cone model, and an asymmetric cone model. These models allow us to determine the three dimensional parameters of HCMEs such as radial speed, angular width, and the angle (γ) between sky plane and cone axis. We compare these parameters obtained from three models using 62 well-observed HCMEs observed by SOHO/LASCO from 2001 to 2002. Then we obtain the root mean square error (RMS error) between maximum measured projection speeds and their calculated projection speeds from the cone models. As a result, we find that the radial speeds obtained from the models are well correlated with one another (R > 0.84). The correlation coefficients between angular widths are ranges from 0.04 to 0.53 and those between γ values are from -0.15 to 0.47, which are much smaller than expected. The reason may be due to different assumptions and methods. The RMS errors between the maximum measured projection speeds and the maximum estimated projection speeds of the elliptical cone model, the ice-cream cone model, and the asymmetric cone model are 213 km/s, 254 km/s, and 267 km/s, respectively. And we obtain the correlation coefficients between the location from the models and the flare location (R > 0.75). Finally, we discuss strengths and weaknesses of these models in terms of space weather application.

Cone photoreceptor definition on adaptive optics retinal imaging

PubMed Central

Muthiah, Manickam Nick; Gias, Carlos; Chen, Fred Kuanfu; Zhong, Joe; McClelland, Zoe; Sallo, Ferenc B; Peto, Tunde; Coffey, Peter J; da Cruz, Lyndon

2014-01-01

Aims To quantitatively analyse cone photoreceptor matrices on images captured on an adaptive optics (AO) camera and assess their correlation to well-established parameters in the retinal histology literature. Methods High resolution retinal images were acquired from 10 healthy subjects, aged 20–35 years old, using an AO camera (rtx1, Imagine Eyes, France). Left eye images were captured at 5° of retinal eccentricity, temporal to the fovea for consistency. In three subjects, images were also acquired at 0, 2, 3, 5 and 7° retinal eccentricities. Cone photoreceptor density was calculated following manual and automated counting. Inter-photoreceptor distance was also calculated. Voronoi domain and power spectrum analyses were performed for all images. Results At 5° eccentricity, the cone density (cones/mm2 mean±SD) was 15.3±1.4×103 (automated) and 13.9±1.0×103 (manual) and the mean inter-photoreceptor distance was 8.6±0.4 μm. Cone density decreased and inter-photoreceptor distance increased with increasing retinal eccentricity from 2 to 7°. A regular hexagonal cone photoreceptor mosaic pattern was seen at 2, 3 and 5° of retinal eccentricity. Conclusions Imaging data acquired from the AO camera match cone density, intercone distance and show the known features of cone photoreceptor distribution in the pericentral retina as reported by histology, namely, decreasing density values from 2 to 7° of eccentricity and the hexagonal packing arrangement. This confirms that AO flood imaging provides reliable estimates of pericentral cone photoreceptor distribution in normal subjects. PMID:24729030

Evolutionary transformation of rod photoreceptors in the all-cone retina of a diurnal garter snake

PubMed Central

Schott, Ryan K.; Müller, Johannes; Yang, Clement G. Y.; Bhattacharyya, Nihar; Chan, Natalie; Xu, Mengshu; Morrow, James M.; Ghenu, Ana-Hermina; Loew, Ellis R.; Tropepe, Vincent; Chang, Belinda S. W.

2016-01-01

Vertebrate retinas are generally composed of rod (dim-light) and cone (bright-light) photoreceptors with distinct morphologies that evolved as adaptations to nocturnal/crepuscular and diurnal light environments. Over 70 years ago, the “transmutation” theory was proposed to explain some of the rare exceptions in which a photoreceptor type is missing, suggesting that photoreceptors could evolutionarily transition between cell types. Although studies have shown support for this theory in nocturnal geckos, the origins of all-cone retinas, such as those found in diurnal colubrid snakes, remain a mystery. Here we investigate the evolutionary fate of the rods in a diurnal garter snake and test two competing hypotheses: (i) that the rods, and their corresponding molecular machinery, were lost or (ii) that the rods were evolutionarily modified to resemble, and function, as cones. Using multiple approaches, we find evidence for a functional and unusually blue-shifted rhodopsin that is expressed in small single “cones.” Moreover, these cones express rod transducin and have rod ultrastructural features, providing strong support for the hypothesis that they are not true cones, as previously thought, but rather are modified rods. Several intriguing features of garter snake rhodopsin are suggestive of a more cone-like function. We propose that these cone-like rods may have evolved to regain spectral sensitivity and chromatic discrimination as a result of ancestral losses of middle-wavelength cone opsins in early snake evolution. This study illustrates how sensory evolution can be shaped not only by environmental constraints but also by historical contingency in forming new cell types with convergent functionality. PMID:26715746

Fine structure of the retinal photoreceptors of the great horned owl (Bubo virginianus).

PubMed

Braekevelt, C R

1993-01-01

The retinal photoreceptors of the great horned owl (Bubo virginianus) consist of rods, single cones and unequal double cones present in a ratio of about 30:1.2. In the light-adapted state the rods are stout cells which are not felt to undergo retinomotor movements. The rod outer segment consists of a stack of scalloped membranous discs enclosed by the cell membrane. The rod inner segment shows an ellipsoid of mitochondria and a wealth of rough endoplasmic reticulum (RER) and polysomes, Golgi zones and autophagic vacuoles but not hyperboloid of glycogen. Single cones show a slightly tapered outer segment, a heterogenous oil droplet and an ellipsoid of mitochondria at the apex of the inner segment. Double cones consist of a larger chief member which also displays an oil droplet and a slightly smaller accessory member which does not. Both members of the double cone as well as the single cone show a prominent ellipsoid, plentiful polysomes and RER and Golgi zones in the inner segment. Neither single nor double cones possess a condensed paraboloid of glycogen but instead show plentiful scattered glycogen particles. Along the contiguous membranes between accessory and chief cones a few presumed junctional complexes are seen near the external limiting membrane. Judging by their morphology in light-adaptation the cones of this species do not undergo photomechanical movements. Rods and cones (both types) have both invaginated (ribbon) and numerous superficial (conventional) synaptic sites. Rods are more numerous in this nocturnally active bird than is usually noted in avian species.

Spatial structure of cone inputs to receptive fields in primate lateral geniculate nucleus

NASA Astrophysics Data System (ADS)

Reid, R. Clay; Shapley, Robert M.

1992-04-01

HUMAN colour vision depends on three classes of cone photoreceptors, those sensitive to short (S), medium (M) or long (L) wavelengths, and on how signals from these cones are combined by neurons in the retina and brain. Macaque monkey colour vision is similar to human, and the receptive fields of macaque visual neurons have been used as an animal model of human colour processing1. P retinal ganglion cells and parvocellular neurons are colour-selective neurons in macaque retina and lateral geniculate nucleus. Interactions between cone signals feeding into these neurons are still unclear. On the basis of experimental results with chromatic adaptation, excitatory and inhibitory inputs from L and M cones onto P cells (and parvocellular neurons) were thought to be quite specific2,3 (Fig. la). But these experiments with spatially diffuse adaptation did not rule out the 'mixed-surround' hypothesis: that there might be one cone-specific mechanism, the receptive field centre, and a surround mechanism connected to all cone types indiscriminately (Fig. le). Recent work has tended to support the mixed-surround hypothesis4-8. We report here the development of new stimuli to measure spatial maps of the linear L-, M- and S-cone inputs to test the hypothesis definitively. Our measurements contradict the mixed-surround hypothesis and imply cone specificity in both centre and surround.

3D algebraic iterative reconstruction for cone-beam x-ray differential phase-contrast computed tomography.

PubMed

Fu, Jian; Hu, Xinhua; Velroyen, Astrid; Bech, Martin; Jiang, Ming; Pfeiffer, Franz

2015-01-01

Due to the potential of compact imaging systems with magnified spatial resolution and contrast, cone-beam x-ray differential phase-contrast computed tomography (DPC-CT) has attracted significant interest. The current proposed FDK reconstruction algorithm with the Hilbert imaginary filter will induce severe cone-beam artifacts when the cone-beam angle becomes large. In this paper, we propose an algebraic iterative reconstruction (AIR) method for cone-beam DPC-CT and report its experiment results. This approach considers the reconstruction process as the optimization of a discrete representation of the object function to satisfy a system of equations that describes the cone-beam DPC-CT imaging modality. Unlike the conventional iterative algorithms for absorption-based CT, it involves the derivative operation to the forward projections of the reconstructed intermediate image to take into account the differential nature of the DPC projections. This method is based on the algebraic reconstruction technique, reconstructs the image ray by ray, and is expected to provide better derivative estimates in iterations. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a mini-focus x-ray tube source. It is shown that the proposed method can reduce the cone-beam artifacts and performs better than FDK under large cone-beam angles. This algorithm is of interest for future cone-beam DPC-CT applications.

Kinetics of Exocytosis Is Faster in Cones Than in Rods

PubMed Central

Rabl, Katalin; Cadetti, Lucia; Thoreson, Wallace B.

2006-01-01

Cone-driven responses of second-order retinal neurons are considerably faster than rod-driven responses. We examined whether differences in the kinetics of synaptic transmitter release from rods and cones may contribute to differences in postsynaptic response kinetics. Exocytosis from rods and cones was triggered by membrane depolarization and monitored in two ways: (1) by measuring EPSCs evoked in second-order neurons by depolarizing steps applied to presynaptic rods or cones during simultaneous paired whole-cell recordings or (2) by direct measurements of exocytotic increases in membrane capacitance. The kinetics of release was assessed by varying the length of the depolarizing test step. Both measures of release revealed two kinetic components to the increase in exocytosis as a function of the duration of a step depolarization. In addition to slow sustained components in both cell types, the initial fast component of exocytosis had a time constant of <5 ms in cones, >10-fold faster than that of rods. Rod/cone differences in the kinetics of release were substantiated by a linear correlation between depolarization-evoked capacitance increases and EPSC charge transfer. Experiments on isolated rods indicate that the slower kinetics of exocytosis from rods was not a result of rod–rod coupling. The initial rapid release of vesicles from cones can shape the postsynaptic response and may contribute to the faster responses of cone-driven cells observed at light offset. PMID:15872111

Visual modelling suggests a weak relationship between the evolution of ultraviolet vision and plumage coloration in birds.

PubMed

Lind, O; Delhey, K

2015-03-01

Birds have sophisticated colour vision mediated by four cone types that cover a wide visual spectrum including ultraviolet (UV) wavelengths. Many birds have modest UV sensitivity provided by violet-sensitive (VS) cones with sensitivity maxima between 400 and 425 nm. However, some birds have evolved higher UV sensitivity and a larger visual spectrum given by UV-sensitive (UVS) cones maximally sensitive at 360-370 nm. The reasons for VS-UVS transitions and their relationship to visual ecology remain unclear. It has been hypothesized that the evolution of UVS-cone vision is linked to plumage colours so that visual sensitivity and feather coloration are 'matched'. This leads to the specific prediction that UVS-cone vision enhances the discrimination of plumage colours of UVS birds while such an advantage is absent or less pronounced for VS-bird coloration. We test this hypothesis using knowledge of the complex distribution of UVS cones among birds combined with mathematical modelling of colour discrimination during different viewing conditions. We find no support for the hypothesis, which, combined with previous studies, suggests only a weak relationship between UVS-cone vision and plumage colour evolution. Instead, we suggest that UVS-cone vision generally favours colour discrimination, which creates a nonspecific selection pressure for the evolution of UVS cones. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Visual pigment coexpression in all cones of two rodents, the Siberian hamster, and the pouched mouse.

PubMed

Lukáts, Akos; Dkhissi-Benyahya, Ouria; Szepessy, Zsuzsanna; Röhlich, Pál; Vígh, Béla; Bennett, Nigel C; Cooper, Howard M; Szél, Agoston

2002-07-01

To decide whether the identical topography of short- and middle-wavelength cone photoreceptors in two species of rodents reflects the presence of both opsins in all cone cells. Double-label immunocytochemistry using antibodies directed against short-wavelength (S)-and middle- to long-wavelength (M/L)-sensitive opsin were used to determine the presence of visual pigments in cones of two species of rodents, the Siberian hamster (Phodopus sungorus) and the pouched mouse (Saccostomus campestris) from South Africa. Topographical distribution was determined from retinal whole-mounts, and the colocalization of visual pigments was examined using confocal laser scanning microscopy. Opsin colocalization was also confirmed in consecutive semithin tangential sections. The immunocytochemical results demonstrate that in both the Siberian hamster and the pouched mouse all retinal cones contain two visual pigments. No dorsoventral gradient in the differential expression of the two opsins is observed. The retina of the Siberian hamster and the pouched mouse is the first example to show a uniform coexpression of M and S cone opsins in all cones, without any topographical gradient in opsin expression. This finding makes these two species good models for the study of molecular control mechanisms in opsin coexpression in rodents, and renders them suitable as sources of dual cones for future investigations on the role and neural connections of this cone type.