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Sample records for altus cumulus electrification

  1. ALTUS Cumulus Electrification Study (ACES)

    NASA Technical Reports Server (NTRS)

    Kim, Tony; Blakeslee, Richard; Russell, Larry W. (Technical Monitor)

    2002-01-01

    The ALTUS Cumulus Electrification Study (ACES) is an uninhabited aerial vehicle (UAV)-based project that will investigate thunderstorms in the vicinity of the Florida Everglades in August 2002. ACES is being conducted to both investigate storm electrical activity and its relationship to storm morphology, and validate Tropical Rainfall Measurement Mission (TRMM) satellite measurements. In addition, as part of NASA's UAV-based science demonstration program, this project will provide a scientifically useful demonstration of the utility and promise of UAV platforms for Earth science and applications observations. Part of the demonstration involves getting approvals from the Federal Aviation Administration and the NASA airworthiness flight safety review board. ACES will employ the ALTUS II aircraft, built by General Atomics - Aeronautical Systems, Inc. Key science objectives simultaneously addressed by ACES are to: (1) investigate lightning-storm relationships, (2) study storm electrical budgets, and (3) provide Lightning Imaging Sensor validation. The ACES payload, already developed and flown on ALTUS, includes electrical, magnetic, and optical sensors to remotely characterize the lightning activity and the electrical environment within and around thunderstorms. ACES will contribute important electrical and optical measurements not available from other sources. Also, the high altitude vantage point of the UAV observing platform (up to 55,000 feet) offers a useful 'cloud-top' perspective. By taking advantage of its slow flight speed (70 to 100 knots), long endurance, and high altitude flight, the ALTUS will be flown near, and when possible, above (but never into) thunderstorms for long periods of time, allowing investigations to be conducted over entire storm life cycles. In addition, concurrent ground-based observations will enable the UAV measurements to be more completely interpreted and evaluated in the context of the thunderstorm structure, evolution, and

  2. The Altus Cumulus Electrification Study (ACES): A UAV-based Investigation of Thunderstorms

    NASA Technical Reports Server (NTRS)

    Blakeslee, Richard; Arnold, James E. (Technical Monitor)

    2001-01-01

    The Altus Cumulus Electrification Study (ACES) is a NASA-sponsored and -led science investigation that utilizes an uninhabited aerial vehicle (UAV) to investigate thunderstorms in the vicinity of the NASA Kennedy Space Center, Florida. As part of NASA's UAV-based science demonstration program, ACES will provide a scientifically useful demonstration of the utility and promise of UAV platforms for Earth science and applications observations. ACES will employ the Altus 11 aircraft, built by General Atomics-Aeronautical Systems, Inc. By taking advantage of its slow flight speed (70 to 100 knots), long endurance, and high-altitude flight (up to 55,000 feet), the Altus will be flown near, and when possible, above (but never into) thunderstorms for long periods of time, allowing investigations to be conducted over entire storm life cycles. Key science objectives simultaneously addressed by ACES are to: (1) investigate lightning-storm relationships, (2) study storm electrical budgets, and (3) provide Lightning Imaging Sensor validation. The ACES payload, already developed and flown on Altus, includes electrical, magnetic, and optical sensors to remotely characterize the lightning activity and the electrical environment within and around thunderstorms. The ACES field campaign will be conducted during July 2002 with a goal of performing 8 to 10 UAV flights. Each flight will require about 4 to 5 hours on station at altitudes from 40,000 ft to 55,000 ft. The ACES team is comprised of scientists from the NASA Marshall Space Flight Center and NASA Goddard Space Flight Centers partnered with General Atomics and IDEA, LLC.

  3. The Altus Cumulus Electrification Study (ACES): A UAV-Based Science Demonstration

    NASA Technical Reports Server (NTRS)

    Blakeslee, R. J.; Croskey, C. L.; Desch, M. D.; Farrell, W. M.; Goldberg, R. A.; Houser, J. G.; Kim, H. S.; Mach, D. M.; Mitchell, J. D.; Stoneburner, J. C.

    2003-01-01

    The Altus Cumulus Electrification Study (ACES) is an unmanned aerial vehicle (UAV)- based project that investigated thunderstorms in the vicinity of the Florida Everglades in August 2002. ACES was conducted to investigate storm electrical activity and its relationship to storm morphology, and to validate satellite-based lightning measurements. In addition, as part of the NASA sponsored UAV-based science demonstration program, this project provided a scientifically useful demonstration of the utility and promise of UAV platforms for Earth science and applications observations. ACES employed the Altus II aircraft, built by General Atomics - Aeronautical Systems, Inc. Key science objectives simultaneously addressed by ACES are to: (1) investigate lightning-storm relationships, (2) study storm electrical budgets, and provide Lightning Imaging Sensor validation. The ACES payload included electrical, magnetic, and optical sensors to remotely characterize the lightning activity and the electrical environment within and around thunderstorms. ACES contributed important electrical and optical measurements not available from other sources. Also, the high altitude vantage point of the UAV observing platform (up to 55,000 feet) provided cloud-top perspective. By taking advantage of its slow flight speed (70 to 100 knots), long endurance, and high altitude flight, the Altus was flown near, and when possible, over (but never into) thunderstorms for long periods of time that allowed investigations to be conducted over entire storm life cycles. An innovative real time weather system was used to identify and vector the aircraft to selected thunderstorms and safely fly around these storms, while, at the same time monitor the weather near our base of operations. In addition, concurrent ground-based observations that included radar (Miami and Key West WSRBD, NASA NPOL), satellite imagery, and lightning (NALDN and Los Alamos EDOT) enable the UAV measurements to be more completely

  4. Preliminary Optical And Electric Field Pulse Statistics From Storm Overflights During The Altus Cumulus Electrification Study

    NASA Technical Reports Server (NTRS)

    Mach, D. A.; Blakeslee, R. J.; Bailey, J. C.; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, J. G.

    2003-01-01

    The Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect high resolution optical pulse and electric field data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses with associated electric field changes. Most of these observations were made while close to the top of the storms. We found filtered mean and median 10-10% optical pulse widths of 875 and 830 microns respectively while the 50-50% mean and median optical pulse widths are 422 and 365 microns respectively. These values are similar to previous results as are the 10-90% mean and median rise times of 327 and 265 microns. The peak electrical to optical pulse delay mean and median were 209 and 145 microns which is longer than one would expect from theoretical results. The results of the pulse analysis will contribute to further validation of the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS) satellites. Pre-launch estimates of the flash detection efficiency were based on a small sample of optical pulse measurements associated with less than 350 lightning discharges collected by NASA U-2 aircraft in the early 1980s. Preliminary analyses of the ACES measurements show that we have greatly increased the number of optical pulses available for validation of the LIS and other orbital lightning optical sensors. Since the Altus was often close to the cloud tops, many of the optical pulses are from low-energy pulses. From these low-energy pulses, we can determine the fraction of optical lightning pulses below the thresholds of LIS, OTD, and any future satellite-based optical sensors such as the geostationary Lightning Mapping Sensor.

  5. Preliminary Optical And Electric Field Pulse Statistics From Storm Overflights During The Altus Cumulus Electrification Study

    NASA Technical Reports Server (NTRS)

    Mach, D. A.; Blakeslee, R. J.; Bailey, J. C.; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, J. G.

    2003-01-01

    The Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect high resolution optical pulse and electric field data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses with associated electric field changes. Most of these observations were made while close to the top of the storms. We found filtered mean and median 10-10% optical pulse widths of 875 and 830 microns respectively while the 50-50% mean and median optical pulse widths are 422 and 365 microns respectively. These values are similar to previous results as are the 10-90% mean and median rise times of 327 and 265 microns. The peak electrical to optical pulse delay mean and median were 209 and 145 microns which is longer than one would expect from theoretical results. The results of the pulse analysis will contribute to further validation of the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS) satellites. Pre-launch estimates of the flash detection efficiency were based on a small sample of optical pulse measurements associated with less than 350 lightning discharges collected by NASA U-2 aircraft in the early 1980s. Preliminary analyses of the ACES measurements show that we have greatly increased the number of optical pulses available for validation of the LIS and other orbital lightning optical sensors. Since the Altus was often close to the cloud tops, many of the optical pulses are from low-energy pulses. From these low-energy pulses, we can determine the fraction of optical lightning pulses below the thresholds of LIS, OTD, and any future satellite-based optical sensors such as the geostationary Lightning Mapping Sensor.

  6. Lightning Optical Pulse Statistics from Storm Overflights During the Altus Cumulus Electrification Study

    NASA Technical Reports Server (NTRS)

    Mach, D. M.; Blakeslee, R. J.; Bailey, J. C.; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, J. G.

    2004-01-01

    The Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect time resolved optical pulse data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses. Most of these observations were made while close to the top of the storms. We divided our data into two amplitude groups based on prior NASA U2 aircraft optical data and our pulse characteristics. The group of large pulses with radiance greater than 2.1 mW /sq m sr had mean and median 10 - 10% optical pulse widths of 765 and 735 microns respectively, the 50-50% pulse widths of 396 and 355 microns respectively, and 10-90% rise times of 290 and 260 microns. These values are very similar to the previous U2 based optical results The other group of pulses consisting of slightly more than a quarter of the total pulses observed had radiances less than the minimum values detected in the U2 study. The small pulses were narrower than the large pulses with 5040% mean and median values of 198 and 160 ps respectively. Only 12 % of the flashes contained only small pulses, minimizing the impact of this data on the estimates of detection efficiencies of the orbital instruments, the Lightning Imaging Sensor and Optical Transient Detector.

  7. Lightning Optical Pulse Statistics from Storm Overflights During the Altus Cumulus Electrification Study

    NASA Technical Reports Server (NTRS)

    Mach, D. M.; Blakeslee, R. J.; Bailey, J. C.; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, J. G.

    2004-01-01

    The Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect time resolved optical pulse data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses. Most of these observations were made while close to the top of the storms. We divided our data into two amplitude groups based on prior NASA U2 aircraft optical data and our pulse characteristics. The group of large pulses with radiance greater than 2.1 mW /sq m sr had mean and median 10 - 10% optical pulse widths of 765 and 735 microns respectively, the 50-50% pulse widths of 396 and 355 microns respectively, and 10-90% rise times of 290 and 260 microns. These values are very similar to the previous U2 based optical results The other group of pulses consisting of slightly more than a quarter of the total pulses observed had radiances less than the minimum values detected in the U2 study. The small pulses were narrower than the large pulses with 5040% mean and median values of 198 and 160 ps respectively. Only 12 % of the flashes contained only small pulses, minimizing the impact of this data on the estimates of detection efficiencies of the orbital instruments, the Lightning Imaging Sensor and Optical Transient Detector.

  8. ALTUS Cumulus Electrification Study (ACES): The application of a UAV for close over-flights of thunderstorms

    NASA Astrophysics Data System (ADS)

    Blakeslee, R.; Mach, D.; Goldberg, R.; Farrell, W.; Desch, M.; Croskey, C.; Mitchell, J.; Houser, J.

    2002-12-01

    In August 2002, General Atomic's Aeronautical Systems Inc.'s ALTUS II UAV made a series of close thunderstorm over-flights during the ALTUS Cumulus Electrification Study (ACES) to 1) determine the nature, occurrence, and power of the upward electrical currents over the storms (conduction vs displacement currents) and their contribution to the global circuit, 2) investigate the storm's lightning history and changing current nature over the storm lifetime, and 3) provide validation products for the Lightning Imaging Sensor (LIS) on Tropical Rainfall Measurement Mission (TRMM). The storm sensor package included electric field mills for the detection of the electrostatic field, a Gerdien probe for sensing the ambient conductivity, an electric field change sensor to determine the ULF and ELF changes associated with lightning and cloud charge distribution, along with boom-mounted 3-axis ELF/VLF electric and magnetic sensors for lightning detection. Optical pulses sensors provided coincidence measurements in the visible and near-IR. A dedicated payload data system allowed the continuous sampling from all the sensors at low sampling rates and also the ability to smart-trigger into high-rate modes during specific "targets of opportunity" (such as lightning strokes, etc.). An innovative real-time weather system allowed the aircraft to be vectored to storms of interest during the campaign. ACES demonstrated the promise and utility of using UAV aircraft to investigate thunderstorms. We will describe the ACES program, the science payload, and the application of the unique UAV capabilities for completion of the science objectives. Preliminary results will also be presented.

  9. The remotely piloted Altus II aircraft probed lightning development with a variety of specialized in

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The remotely piloted Altus II aircraft probed lightning development with a variety of specialized instruments and cameras during a month-long study over Florida during the summer of 2002, including one sensor mounted on a boom extending from Altus' nose. The Altus Cumulus Electrification Study (ACES), led by Dr. Richard Blakeslee of NASA Marshall Space Flight center, focused on the collection of electrical, magnetic and optical measurements of thunderstorms. Data collected will help scientists understand the development and life cycles of thunderstorms, which in turn may allow meteorologists to more accurately predict when destructive storms may hit. The Altus II, built by General Atomics Aeronautical Systems, Inc., is one of several remotely operated aircraft developed and matured under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. The program focused on developing airframe, propulsion, control system and communications technologies to allow unmanned aerial vehicles (UAVs) to operate at very high altitudes for long durations while carrying a variety of sensors, cameras or other instruments for science experiments, surveillance or telecommunications relay missions.

  10. Looking ever so much like an alien spacecraft, the Altus II remotely piloted aircraft shows off some

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Looking ever so much like an alien spacecraft, the Altus II remotely piloted aircraft shows off some of the instruments and camera lenses mounted in its nose for a lightning study over Florida flown during the summer of 2002. The Altus Cumulus Electrification Study (ACES), led by Dr. Richard Blakeslee of NASA Marshall Space Flight center, focused on the collection of electrical, magnetic and optical measurements of thunderstorms. Data collected will help scientists understand the development and life cycles of thunderstorms, which in turn may allow meteorologists to more accurately predict when destructive storms may hit. The Altus II, built by General Atomics Aeronautical Systems, Inc., is one of several remotely operated aircraft developed and matured under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. The program focused on developing airframe, propulsion, control system and communications technologies to allow unmanned aerial vehicles (UAVs) to operate at very high altitudes for long durations while carrying a variety of sensors, cameras or other instruments for science experiments, surveillance or telecommunications relay missions.

  11. Looking ever so much like an alien spacecraft, the Altus II remotely piloted aircraft shows off some

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Looking ever so much like an alien spacecraft, the Altus II remotely piloted aircraft shows off some of the instruments and camera lenses mounted in its nose for a lightning study over Florida flown during the summer of 2002. The Altus Cumulus Electrification Study (ACES), led by Dr. Richard Blakeslee of NASA Marshall Space Flight center, focused on the collection of electrical, magnetic and optical measurements of thunderstorms. Data collected will help scientists understand the development and life cycles of thunderstorms, which in turn may allow meteorologists to more accurately predict when destructive storms may hit. The Altus II, built by General Atomics Aeronautical Systems, Inc., is one of several remotely operated aircraft developed and matured under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. The program focused on developing airframe, propulsion, control system and communications technologies to allow unmanned aerial vehicles (UAVs) to operate at very high altitudes for long durations while carrying a variety of sensors, cameras or other instruments for science experiments, surveillance or telecommunications relay missions.

  12. Altus aircraft on runway

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The remotely piloted Altus aircraft flew several developmental test flights from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif., in 1996. The Altus--the word is Latin for 'high'--is a variant of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. It is designed for high-altitude, long-duration scientific sampling missions, and is powered by a turbocharged four-cylinder piston engine. The first Altus was developed under NASA's Environmental Research Aircraft and Sensor Technology program, while a second Altus was built for a Naval Postgraduate School/Department of Energy program. A pilot in a control station on the ground flew the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system. Equipped with a single-stage turbocharger during the 1996 test flights, the first Altus reached altitudes in the 37,000-foot range, while the similarly-equipped second Altus reached 43,500 feet during developmental flights at Dryden in the summer of 1997. The NASA Altus also set an endurance record of more than 26 hours while flying a science mission in late 1996 and still had an estimated 10 hours of fuel remaining when it landed. Now equipped with a two-stage turbocharger, the NASA Altus maintained an altitude of 55,000 feet for four hours during flight tests in 1999.

  13. Altus aircraft on runway

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The remotely piloted Altus aircraft flew several developmental test flights from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif., in 1996. The Altus--the word is Latin for 'high'--is a variant of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. It is designed for high-altitude, long-duration scientific sampling missions, and is powered by a turbocharged four-cylinder piston engine. The first Altus was developed under NASA's Environmental Research Aircraft and Sensor Technology program, while a second Altus was built for a Naval Postgraduate School/Department of Energy program. A pilot in a control station on the ground flew the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system. Equipped with a single-stage turbocharger during the 1996 test flights, the first Altus reached altitudes in the 37,000-foot range, while the similarly-equipped second Altus reached 43,500 feet during developmental flights at Dryden in the summer of 1997. The NASA Altus also set an endurance record of more than 26 hours while flying a science mission in late 1996 and still had an estimated 10 hours of fuel remaining when it landed. Now equipped with a two-stage turbocharger, the NASA Altus maintained an altitude of 55,000 feet for four hours during flight tests in 1999.

  14. Altus I aircraft on lakebed

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The remotely-piloted Altus I aircraft climbs away after takeoff from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, were designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology program, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet. The Altus II, the first of the two craft to be completed, made its first flight on May 1, 1996. With its engine augmented by a single-stage turbocharger, the Altus II reached an altitude of 37,000 ft during its first series of development flights at Dryden in Aug., 1996. In Oct. of that year, the Altus II was flown in an Atmospheric Radiation Measurement study for the Department of Energy's Sandia National Laboratory in Oklahoma. During the course of those flights, the Altus II set a single-flight endurance record for remotely-operated aircraft of more than 26 hours. The Altus I, completed in 1997, flew a series of development flights at Dryden that summer. Those test flights culminated with the craft reaching an altitude of 43,500 ft while carrying a simulated 300-lb payload, a record for an unmanned aircraft powered by a piston engine augmented with a single-stage turbocharger. The Altus II sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the

  15. Altus I aircraft on lakebed

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The remotely-piloted Altus I aircraft climbs away after takeoff from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, were designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology program, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet. The Altus II, the first of the two craft to be completed, made its first flight on May 1, 1996. With its engine augmented by a single-stage turbocharger, the Altus II reached an altitude of 37,000 ft during its first series of development flights at Dryden in Aug., 1996. In Oct. of that year, the Altus II was flown in an Atmospheric Radiation Measurement study for the Department of Energy's Sandia National Laboratory in Oklahoma. During the course of those flights, the Altus II set a single-flight endurance record for remotely-operated aircraft of more than 26 hours. The Altus I, completed in 1997, flew a series of development flights at Dryden that summer. Those test flights culminated with the craft reaching an altitude of 43,500 ft while carrying a simulated 300-lb payload, a record for an unmanned aircraft powered by a piston engine augmented with a single-stage turbocharger. The Altus II sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the

  16. 27 CFR 9.77 - Altus.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Altus. 9.77 Section 9.77 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.77 Altus. (a)...

  17. 27 CFR 9.77 - Altus.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... The name of the viticultural area described in this section is “Altus.” (b) Approved maps. The appropriate maps for determining the boundaries of the Altus viticultural area are five U.S.G.S. maps in the 7... southeast corner of the city of Ozark, Arkansas (on the Ozark Quadrangle map). (2) Boundary Description: (i...

  18. Altus small button cell performance

    NASA Technical Reports Server (NTRS)

    Freeman, C.; Bis, F.; Warbutton, D. L.

    1981-01-01

    Results of testing performed on Altus lithium thionyl chloride cells are presented. The test plan followed simulates the mine environment. It involves nondestructive testing, ruggedness testing and destructive testing. The nondestructive testing involves open circuit voltage measurements initially on all the cells, alternating current resistance measurements initially on all the cells and closed circuit voltage pulses, 20s on and 20s through 1000, 100, 10 and 1 ohms at temperatures of -54 to 71 C. The ruggedness testing involves low frequency vibration, high frequency vibration, and two-phase water entry shock at temperatures of -54, 25 and 71 C. It also involves thermal shock tests.

  19. The electrification of spacecraft

    NASA Technical Reports Server (NTRS)

    Akishin, A. I.; Novikov, L. S.

    1985-01-01

    Physical and applied aspects of the electrification of space vehicles and natural celestial objects are discussed, the factors resulting in electrification of spacecraft are analyzed, and methods of investigating various phenomena associated with this electrification and ways of protecting spacecraft against the influence of static electricity are described. The booklet is intended for the general reader interested in present day questions of space technology.

  20. Altus I aircraft landing on Edwards lakebed runway 23

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The remotely-piloted Altus I aircraft lands on Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, were designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology program, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet. The Altus II, the first of the two craft to be completed, made its first flight on May 1, 1996. With its engine augmented by a single-stage turbocharger, the Altus II reached an altitude of 37,000 ft during its first series of development flights at Dryden in Aug., 1996. In Oct. of that year, the Altus II was flown in an Atmospheric Radiation Measurement study for the Department of Energy's Sandia National Laboratory in Oklahoma. During the course of those flights, the Altus II set a single-flight endurance record for remotely-operated aircraft of more than 26 hours. The Altus I, completed in 1997, flew a series of development flights at Dryden that summer. Those test flights culminated with the craft reaching an altitude of 43,500 ft while carrying a simulated 300-lb payload, a record for an unmanned aircraft powered by a piston engine augmented with a single-stage turbocharger. The Altus II sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio

  1. Altus I aircraft landing on Edwards lakebed runway 23

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The remotely-piloted Altus I aircraft lands on Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, were designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology program, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet. The Altus II, the first of the two craft to be completed, made its first flight on May 1, 1996. With its engine augmented by a single-stage turbocharger, the Altus II reached an altitude of 37,000 ft during its first series of development flights at Dryden in Aug., 1996. In Oct. of that year, the Altus II was flown in an Atmospheric Radiation Measurement study for the Department of Energy's Sandia National Laboratory in Oklahoma. During the course of those flights, the Altus II set a single-flight endurance record for remotely-operated aircraft of more than 26 hours. The Altus I, completed in 1997, flew a series of development flights at Dryden that summer. Those test flights culminated with the craft reaching an altitude of 43,500 ft while carrying a simulated 300-lb payload, a record for an unmanned aircraft powered by a piston engine augmented with a single-stage turbocharger. The Altus II sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio

  2. Altus II aircraft flying over southern California desert

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The snow-capped peak of Mt. San Antonio in the San Gabriel range is visible as the the remotely piloted Altus II flies over Southern California's high desert. The Altus II was flown as a performance and propulsion testbed for future high-altitude science platform aircraft under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program at the Dryden Flight Research Center, Edwards, Calif. The rear-engined Altus II and its sister ship, the Altus I, were built by General Atomics/Aeronautical Systems, Inc., of San Diego, Calif. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I, built for the Naval Postgraduate School, reached over 43,500 feet with a single-stage turbocharger feeding its four-cylinder Rotax engine in 1997, while the Altus II, incorporating a two-stage turbocharger built by Thermo-Mechanical Systems, reached and sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system.

  3. Altus II aircraft flying over southern California desert

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The San Gabriel range is visible as the the remotely piloted Altus II flies over Southern California's high desert. The Altus II was flown as a performance and propulsion testbed for future high-altitude science platform aircraft under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program at the Dryden Flight Research Center, Edwards, Calif. The rear-engined Altus II and its sister ship, the Altus I, were built by General Atomics/Aeronautical Systems, Inc., of San Diego, Calif. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I, built for the Naval Postgraduate School, reached over 43,500 feet with a single-stage turbocharger feeding its four-cylinder Rotax engine in 1997, while the Altus II, incorporating a two-stage turbocharger built by Thermo-Mechanical Systems, reached and sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system.

  4. Altus I aircraft taking off from lakebed runway

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The remotely-piloted Altus I aircraft takes off from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, were designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology program, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet.

  5. Altus I aircraft in flight, retracting landing gear after takeoff

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The landing gear of the remotely piloted Altus I aircraft retracts into the fuselage after takeoff from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, was designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology project, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet.

  6. Altus I aircraft in flight, retracting landing gear after takeoff

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The landing gear of the remotely piloted Altus I aircraft retracts into the fuselage after takeoff from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, was designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology project, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet.

  7. Altus I aircraft taking off from lakebed runway

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The remotely-piloted Altus I aircraft takes off from Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center, Edwards, Calif. The short series of test flights sponsored by the Naval Postgraduate School in early August, 1997, were designed to demonstrate the ability of the experimental craft to cruise at altitudes above 40,000 feet for sustained durations. On its final flight Aug. 15, the Altus I reached an altitude of 43,500 feet. The Altus I and its sister ship, the Altus II, are variants of the Predator surveillance drone built by General Atomics/Aeronautical Systems, Inc. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I incorporates a single-stage turbocharger, while the Altus II, built for NASA's Environmental Research Aircraft and Sensor Technology program, sports a two-stage turbocharger to enable the craft to fly at altitudes above 55,000 feet.

  8. THUNDERCLOUD ELECTRIFICATION STUDIES, II

    DTIC Science & Technology

    The investigation of the generation of electric charges in thunderclouds included experiments to determine the electrification generated by the...thundercloud electrification . Drop-breaking experiments on 3-mm water drops supercooled to -6 deg and 14 deg C yielded average charges of 6.8 x 10 to the...12 power coulombs/drop,respectively. The magnitudes of electrification varied fromdrop to drop by a factor of 100 or more in all cases. Corona-point

  9. 76 FR 66866 - Proposed Amendment of Class D Airspace; Altus AFB, OK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ... implemented to enhance safety for aircraft operating in the vicinity of Altus/Quartz Mountain Regional Airport... changes implemented to enhance safety for aircraft operating in the vicinity of Altus/Quartz...

  10. Navajo Electrification Demonstraiton Project

    SciTech Connect

    Larry Ahasteen, Project Manager

    2006-07-17

    This is a final technical report required by DOE for the Navajo Electrification Demonstration Program, This report covers the electric line extension project for Navajo families that currently without electric power.

  11. Controversy over rural electrification

    SciTech Connect

    Barnes, D.F.

    1982-10-01

    The disappointing rate of rural electrification in a number of developing countries has raised issues about the equity of utility investments and subsidies since limited connection to the central grid threatens to increase the gap between rich and poor. A review of the arguments for and against central-grid rural electrification cites the efficiency and low cost of electricity, improved productivity, and a way to balance urban and rural investments as the principal benefits. Critics challenge these points and argue that electrification is too costly, has uneven social benefits, and has no direct economic benefits. They feel that the US model of rural electrification may not be applicable to developing countries with a lower per-capita income and that central grid generation lacks the merits of development strategies based on renewable sources and alternative technologies. Studies show that the impact of rural electrification varies among countries, but that even the more successful will require subsidies to ensure that electrification projects are coordinated with social and economic programs. 11 references, 1 table. (DCK)

  12. Installation restoration Program. Records Search, Altus AFB, Oklahoma. Phase 1

    DTIC Science & Technology

    1985-03-01

    limited to, the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA). For study I 4-1 I I purposes, waste petroleum ...posed or recycled through DPDO. Fuels Management The Altus AFB petroleum handling system includes substantial vol- 3 umes of JP-4 jet fuel, diesel fuel...NON-CALCAREOUS: Not bearing calcium carbonate (CaCO3 ) a characteristic I mineral of marine paleoenvironment . NPDES: National Pollutant Discharge

  13. 33 CFR 208.26 - Altus Dam and Reservoir, North Fork Red River, Okla.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Altus Dam and Reservoir, North Fork Red River, Okla. 208.26 Section 208.26 Navigation and Navigable Waters CORPS OF ENGINEERS..., North Fork Red River, Okla. The Bureau of Reclamation, or its designated agent, shall operate the Altus...

  14. 33 CFR 208.26 - Altus Dam and Reservoir, North Fork Red River, Okla.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Altus Dam and Reservoir, North Fork Red River, Okla. 208.26 Section 208.26 Navigation and Navigable Waters CORPS OF ENGINEERS..., North Fork Red River, Okla. The Bureau of Reclamation, or its designated agent, shall operate the Altus...

  15. 77 FR 4457 - Amendment of Class D Airspace; Altus AFB, OK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-30

    ... From the Federal Register Online via the Government Publishing Office #0; #0;Rules and Regulations.... Procedural changes implemented to enhance safety for aircraft operating in the vicinity of Altus/Quartz Mountain Regional Airport, Altus, OK, has made this action necessary for the safety and management of...

  16. 78 FR 50134 - Altus Pharmaceuticals, Inc., Blackhawk Capital Group BDC, Inc., Cargo Connection Logistics...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Altus Pharmaceuticals, Inc., Blackhawk Capital Group BDC, Inc., Cargo Connection Logistics Holding... securities of Altus Pharmaceuticals, Inc. because it has not filed any periodic reports since the period...

  17. Electrification and Electric Guns,

    DTIC Science & Technology

    1984-02-03

    1657-83F/203 N Si FIE FG2/ f i l l ’ I g u I 12 . 8 l . 11111.2 I.UJ M Lfl 00 FOREIGN TECHNOLOGY DIVISION 0 .N ELECTRIFICATION AND ELECTRIC GUNS by A.A...available. i I Accessiton For I ’IS op:" I (31odes ELECTRIFICATION AND ELECTRIC GUNS DI t pe:i c A. A. Kr’vProf. Th .~Pis Presen~tly in the stage of...cor.sderaticn; the wrnd’o en "onrr-:- rea -nes the steady state are considered. ’her. se : " rren :n an electric gun is shorted, the power :s ex;end e

  18. Altus II high altitude science aircraft decending toward U.S. Navy's Pacific Missile Range Facility

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Altus II descends towards the Navy's Pacific Missile Range Facility, Kauai, Hawaii. The Altus II was flown as a performance and propulsion testbed for future high-altitude science platform aircraft under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program at the Dryden Flight Research Center, Edwards, Calif. The rear-engined Altus II and its sister ship, the Altus I, were built by General Atomics/Aeronautical Systems, Inc., of San Diego, Calif. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I, built for the Naval Postgraduate School, reached over 43,500 feet with a single-stage turbocharger feeding its four-cylinder Rotax engine in 1997, while the Altus II, incorporating a two-stage turbocharger built by Thermo-Mechanical Systems, reached and sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system.

  19. Altus II high altitude science aircraft decending toward U.S. Navy's Pacific Missile Range Facility

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Altus II descending from a flight over Kauai, Hawaii. The Altus II was flown as a performance and propulsion testbed for future high-altitude science platform aircraft under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program at the Dryden Flight Research Center, Edwards, Calif. The rear-engined Altus II and its sister ship, the Altus I, were built by General Atomics/Aeronautical Systems, Inc., of San Diego, Calif. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I, built for the Naval Postgraduate School, reached over 43,500 feet with a single-stage turbocharger feeding its four-cylinder Rotax engine in 1997, while the Altus II, incorporating a two-stage turbocharger built by Thermo-Mechanical Systems, reached and sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system.

  20. Altus II high altitude science aircraft decending toward U.S. Navy's Pacific Missile Range Facility

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Altus II descending from a flight over Kauai, Hawaii. The Altus II was flown as a performance and propulsion testbed for future high-altitude science platform aircraft under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program at the Dryden Flight Research Center, Edwards, Calif. The rear-engined Altus II and its sister ship, the Altus I, were built by General Atomics/Aeronautical Systems, Inc., of San Diego, Calif. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I, built for the Naval Postgraduate School, reached over 43,500 feet with a single-stage turbocharger feeding its four-cylinder Rotax engine in 1997, while the Altus II, incorporating a two-stage turbocharger built by Thermo-Mechanical Systems, reached and sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system.

  1. Altus II high altitude science aircraft decending toward U.S. Navy's Pacific Missile Range Facility

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Altus II descends towards the Navy's Pacific Missile Range Facility, Kauai, Hawaii. The Altus II was flown as a performance and propulsion testbed for future high-altitude science platform aircraft under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program at the Dryden Flight Research Center, Edwards, Calif. The rear-engined Altus II and its sister ship, the Altus I, were built by General Atomics/Aeronautical Systems, Inc., of San Diego, Calif. They are designed for high-altitude, long-duration scientific sampling missions, and are powered by turbocharged piston engines. The Altus I, built for the Naval Postgraduate School, reached over 43,500 feet with a single-stage turbocharger feeding its four-cylinder Rotax engine in 1997, while the Altus II, incorporating a two-stage turbocharger built by Thermo-Mechanical Systems, reached and sustained an altitudeof 55,000 feet for four hours in 1999. A pilot in a control station on the ground flies the craft by radio signals, using visual cues from a video camera in the nose of the Altus and information from the craft's air data system.

  2. Chile rural electrification cooperation

    SciTech Connect

    Flowers, L.

    1997-12-01

    The author describes a joint program to use renewables for rural electrification projects in Chile. The initial focus was in a limited part of the country, involving wind mapping, pilot project planning, training, and development of methodologies for comparative evaluations of resources. To this point three wind hybrid systems have been installed in one region, as a part of the regional private utility, and three additional projects are being designed. Additional resource assessment and training is ongoing. The author points out the difficulties in working with utilities, the importance of signed documentation, and the need to look at these programs as long term because of the time involved in introducing such new technologies.

  3. NAVAJO ELECTRIFICATION DEMONSTRATION PROJECT

    SciTech Connect

    Terry W. Battiest

    2008-06-11

    The Navajo Electrification Demonstration Project (NEDP) is a multi-year project which addresses the electricity needs of the unserved and underserved Navajo Nation, the largest American Indian tribe in the United States. The program serves to cumulatively provide off-grid electricty for families living away from the electricty infrastructure, line extensions for unserved families living nearby (less than 1/2 mile away from) the electricity, and, under the current project called NEDP-4, the construction of a substation to increase the capacity and improve the quality of service into the central core region of the Navajo Nation.

  4. EVOLUTION OF INDIVIDUAL CUMULUS,

    DTIC Science & Technology

    In this paper, the evolution of individual cumulus is studied with basic equations involving the drag effect of water droplets and the phase...the thermal conditions and other properties in the evolution process. It is shown that the drag and phase transformation effects on cloud

  5. Dryden's David Bushman explains the capabilities of the Altus UAV to NASA Langley's Charles Hudgins

    NASA Image and Video Library

    2003-05-27

    David Bushman, unmanned aerial vehicle (UAV) mission manager in NASA Dryden's Airborne Science Program, explains the capabilities of the Altus UAV to Charles Hudgins of NASA Langley's Chemistry and Dynamics Branch.

  6. Interstate Electrification Improvement Project

    SciTech Connect

    Puckette, Margaret; Kim, Jeff

    2015-07-01

    The Interstate Electrification Improvement Project, publicly known as the Shorepower Truck Electrification Project (STEP), started in May 2011 and ended in March 2015. The project grant was awarded by the Department of Energy’s Vehicles Technology Office in the amount of $22.2 million. It had three overarching missions: 1. Reduce the idling of Class 8 tractors when parked at truck stops, to reduce diesel fuel consumption and thus U.S. dependence on foreign petroleum; 2. Stimulate job creation and economic activity as part of the American Reinvestment and Recovery Act of 2009; 3. Reduce greenhouse gas emissions (GHG) from diesel combustion and the carbon footprint of the truck transportation industry. The project design was straightforward. First, build fifty Truck Stop Electrification (TSE) facilities in truck stop parking lots across the country so trucks could plug-in to 110V, 220V, or 480VAC, and shut down the engine instead of idling. These facilities were strategically located at fifty truck stops along major U.S. Interstates with heavy truck traffic. Approximately 1,350 connection points were installed, including 150 high-voltage electric standby Transport Refrigeration Unit (eTRU) plugs--eTRUs are capable of plugging in to shore power1 to cool the refrigerated trailer for loads such as produce, meats and ice cream. Second, the project provided financial incentives on idle reduction equipment to 5,000 trucks in the form of rebates, to install equipment compatible with shore power. This equipment enables drivers to shut down the main engine when parked, to heat or cool their cab, charge batteries, or use other household appliances without idling—a common practice that uses approximately 1 gallon of diesel per hour. The rebate recipients were intended to be the first fleets to plug into Shorepower to save diesel fuel and ensure there is significant population of shore power capable trucks. This two part project was designed to complement each other by

  7. Truckstop -- and Truck!-- Electrification

    SciTech Connect

    Skip Yeakel

    2001-12-13

    The conclusions of this paper are: 0.5-1.5 G/H and/or BUSG/Y--how much time and money will it take to quantify and WHY BOTHER TO DO SO? No shortage of things to do re truckstop--+ truck!-- electrification; Better that government and industry should put many eggs in lots of baskets vs. all in one or few; Best concepts will surface as most viable; Economic appeal better than regulation or brute force; Launch Ground Freight Partnership and give it a chance to work; Demonstration is an effective means to educate, and learn from, customers--learning is a two way street; Research, Development, Demonstration, and Deployment (RD 3) are all important but only deployment gets results; TSE can start small in numbers of spaces to accommodate economically inspired growth but upfront plans should be made for expansion if meaningful idle reduction is to follow via TE; 110VAC 15A service/ parking space is minimal--if infrastructure starts like this, upfront plans must be made to increase capacity; Increased electrification of truckstop and truck alike will result in much better life on the road; Improved sleep will improve driver alertness and safety; Reduced idling will significantly reduce fuel use and emissions; Universal appeal for DOD, DOE, DOT, EPA, OEMs, and users alike; Clean coal, gas, hydro, nuclear, or wind energy sources are all distinctly American means by which to generate electricity; Nothing can compete with diesel fuel to serve mobile truck needs; stationary trucks are like power plants--they don't move and should NOT be powered by petroleum products whenever possible; Use American fueled power plants--electricity--to serve truck idling needs wherever practical to do so; encourage economic aspect; Create and reward industry initiatives to reduce fuel use; Eliminate FET on new trucks, provide tax credits (non highway fuel use and investment), provide incentives based on results; Encourage newer/ cleaner truck use; solicit BAAs with mandatory OEM/ fleet

  8. Aircraft Electrification in Clouds and Precipitation,

    DTIC Science & Technology

    The electrification of the airplane may distort the results of micro-physical observation of the clouds, particularly the measurement of the... electrification of the airplane and cloud parameters is discussed. Experimental data on electrification in different meteorological conditions are given. (Author)

  9. On cumulus mergers

    NASA Technical Reports Server (NTRS)

    Simpson, J.; Westcott, N. E.; Clerman, R. J.; Pielke, R. A.

    1980-01-01

    A study of cumulus mergers for three undisturbed untreated days in the summer of 1973 is reported. Mergers produce more than an order of magnitude more rain than unmerged echoes, while mergers of mergers produce still an order of magnitude more rain. Duration, echo area, and rain depths are also compared for merged and unmerged systems, and each day is analyzed individually, indicating a correlation between organization and rain amount. The relevance of mergers to hydrology, weather modification, and the large-scale impacts of convective clouds is discussed.

  10. A numerical study of aerosol effects on electrification of thunderstorms

    NASA Astrophysics Data System (ADS)

    Tan, Y. B.; Shi, Z.; Chen, Z. L.; Peng, L.; Yang, Y.; Guo, X. F.; Chen, H. R.

    2017-02-01

    Numerical simulations are performed to investigate the effect of aerosol on microphysical and electrification in thunderstorm clouds. A two-dimensional (2-D) cumulus model with electrification scheme including non-inductive and inductive charge separation is used. The concentration of aerosol particles with distribution fitted by superimposing three log-normal distributions rises from 50 to 10,000 cm-3. The results show that the response of charge separation rate to the increase of aerosol concentration is nonmonotonic. When aerosol concentration is changed from 50 to 1000 cm-3, a stronger formation of cloud droplet, graupel and ice crystal results in increasing charge separation via non-inductive and inductive mechanism. However, in the range of 1000-3000 cm-3, vapor competition arises in the decrease of ice crystal mixing ratio and the reduction of ice crystals size leads to a slightly decrease in non-inductive charge rate, while inductive charging rate has no significant change in magnitude. Above aerosol concentration of 3000 cm-3, the magnitude of charging rate which keeps steady is insensitive to the increase in aerosol concentration. The results also suggest that non-inductive charge separation between ice crystal and graupel contributes to the main upper positive charge region and the middle negative charge region. Inductive graupel-cloud droplet charge separation, on the other hand, is found to play an important role in the development of lower charge region.

  11. Contact electrification of insulating materials

    NASA Astrophysics Data System (ADS)

    Lacks, Daniel J.; Mohan Sankaran, R.

    2011-11-01

    The electrostatic charge that is generated when two materials are contacted or rubbed and then separated is a well-known physical process that has been studied for more than 2500 years. Contact electrification occurs in many contexts, both natural and technological. For example, in dust storms the collisions between particles lead to electrostatic charging and in extreme cases, extraordinary lightning displays. In electrophotography, toner particles are intentionally charged to guide their deposition in well-defined patterns. Despite such a long history and so many important consequences, a fundamental understanding of the mechanism behind contact electrification remains elusive. An open question is what type of species are transferred between the surfaces to generate charge—experiments suggest various species ranging from electrons to ions to nanoscopic bits of material, and theoretical work suggests that non-equilibrium states may play an important role. Another open question is the contact electrification that occurs when two insulating materials with identical physical properties touch—since there is no apparent driving force, it is not clear why charge transfer occurs. A third open question involves granular systems—models and experiments have shown that a particle-size dependence for the charging often exists. In this review, we discuss the fundamental aspects of contact electrification and highlight recent research efforts aimed at understanding these open questions.

  12. Red-based cumulus.

    PubMed

    Gedzelman, Stanley David

    2015-02-01

    Observations and model simulations of cumulus clouds whose bases are tinted red when the Sun is well above the horizon are presented. Conditions for seeing red bases include (1) a red underlying surface (which may consist of dust clouds, as from haboobs) with high albedo, (2) small fractional cloud cover when the Sun is far enough below the zenith for direct sunlight to illuminate much of the surface directly below and around cloud base, (3) optically thick clouds so that the bases are dark, and (4) clouds with bases that are near enough to the observer to appear high in the sky so that the admixture of scattered light from the intervening atmosphere is minimized.

  13. A Numerical Study of Thunderstorm Electrification: Initial Electrification and Thunderstorm Climatology

    DTIC Science & Technology

    1991-11-15

    UNLIMITED. 13. ABSTRACT (MAfmmuin 200 WOMj Our purpose is to identify those atmospheric conditions that lead to thunderstorm electrification . We have...thunderstorm electrification . We have collected aircraft and radar measurements of atmospheric parameters made during several recent intensive field studies...Initial Electrification and Thunderstorm Climatology Marcia Baker and Robert Solomon Atmospheric Sciences Department AK-40, iniversity of Washington

  14. Sustainability of TCE Removal in the Mulch Biowalls at Altus AFB

    EPA Science Inventory

    A permeable mulch biowall was installed in June 2002 at Landfill 3 (LF-03), Operable Unit 1 (OU-1), Altus AFB, Oklahoma. The demonstration was conducted by Parsons for the AFCEE Technology Transfer Outreach Office. The biowall is approximately 455 feet long, by 24 feet deep, by...

  15. Sustainability of TCE Removal in the Mulch Biowalls at Altus AFB

    EPA Science Inventory

    A permeable mulch biowall was installed in June 2002 at Landfill 3 (LF-03), Operable Unit 1 (OU-1), Altus AFB, Oklahoma. The demonstration was conducted by Parsons for the AFCEE Technology Transfer Outreach Office. The biowall is approximately 455 feet long, by 24 feet deep, by...

  16. American Recovery and Reinvestment Act (ARRA) Federal Energy Management Program Technical Assistance Project 224 Altus Air Force Base Solar Technologies

    SciTech Connect

    Russo, Bryan J.

    2010-09-30

    The principal goal of this project was to evaluate altus Air Force Base for building integrated silicon or thin film module photovoltaic opportunities. This report documents PNNL's efforts and documents study conclusions.

  17. Nanojets: Electrification, Energetics, Dynamics, Stability and Breakup

    DTIC Science & Technology

    2007-11-01

    LUvrcry,LL, k........ , I Final Technical Report 115 May 2007 - 30 November 2007 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanojets: Electrification ...are code) Unclassified Unclassified Unclassified (703) Standard Form 298 (Rev. 8-98 Prescribed by ANSI-Std Z39-18 FINAL REPORT Nanojets: Electrification

  18. Nanojets: Electrification, Energetics, Dynamics, Stability and Breakup

    DTIC Science & Technology

    2006-12-31

    20/2007 FINAL 02/15/2004-12/31/2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanojets: Electrification , Energetics, Dynamics, Stability and Breakup...NUMBER finclude area code)UUU64 404.894.3368 Standard Form 298 (Rev. 8/98) Prescribed by ANSI SId. Z39.18 FINAL REPORT Nanojets: Electrification

  19. Cumulus role in tropical circulations

    NASA Technical Reports Server (NTRS)

    Simpson, J.

    1983-01-01

    The present investigation is concerned with the effects of cumulus clouds upon their surroundings, and the interaction of the cumulus scale of motion with the larger scales of motion in the tropics. Charney and Eliassen (1964) have conducted a study of the growth of the hurricane depression and proposed the CISK (Conditional Instability of the Second Kind) mechanism. The CISK concept was used in several of the pioneering models of hurricanes and tropical disturbances. Since the 1960's, the CISK concept has been generalized and extended. However, the feedback between convection and the large-scale flow is still positive. In the present investigation the philosophy is extended to a negative feedback which contributes to the stability (mainly in direction) of the trade winds. Attention is given to the classical Ekman layer and early CISK, cumulus momentum transports, the role of cumuli in the trade-wind moisture and heat budgets, the trade wind model, and the equatorial trough and hot tower hypothesis.

  20. Cumulus role in tropical circulations

    NASA Technical Reports Server (NTRS)

    Simpson, J.

    1983-01-01

    The present investigation is concerned with the effects of cumulus clouds upon their surroundings, and the interaction of the cumulus scale of motion with the larger scales of motion in the tropics. Charney and Eliassen (1964) have conducted a study of the growth of the hurricane depression and proposed the CISK (Conditional Instability of the Second Kind) mechanism. The CISK concept was used in several of the pioneering models of hurricanes and tropical disturbances. Since the 1960's, the CISK concept has been generalized and extended. However, the feedback between convection and the large-scale flow is still positive. In the present investigation the philosophy is extended to a negative feedback which contributes to the stability (mainly in direction) of the trade winds. Attention is given to the classical Ekman layer and early CISK, cumulus momentum transports, the role of cumuli in the trade-wind moisture and heat budgets, the trade wind model, and the equatorial trough and hot tower hypothesis.

  1. Summary of Cumulus Parameterization Workshop

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Starr, David OC.; Hou, Arthur; Newman, Paul; Sud, Yogesh

    2002-01-01

    A workshop on cumulus parameterization took place at the NASA Goddard Space Flight Center from December 3-5, 2001. The major objectives of this workshop were (1) to review the problem of representation of moist processes in large-scale models (mesoscale models, Numerical Weather Prediction models and Atmospheric General Circulation Models), (2) to review the state-of-the-art in cumulus parameterization schemes, and (3) to discuss the need for future research and applications. There were a total of 31 presentations and about 100 participants from the United States, Japan, the United Kingdom, France and South Korea. The specific presentations and discussions during the workshop are summarized in this paper.

  2. Municipal energy planning: the Oklahoma experience. [Communities of Altus and Edmond

    SciTech Connect

    McDowell, M.

    1980-01-01

    Leadership demonstrated in the Oklahoma communities of Altus and Edmond illustrates the importance of municipal planning for energy crises. A natural gas generating plant in Altus had been closed down because wholesale rates from the Public Service Company of Oklahoma (PSO) were more attractive. Legal challenges to PSO's efforts to raise rates after 1973 led to a comprehensive management study aimed at reducing system costs without jeopardizing service. The city set a goal of reducing consumption by 30 percent and an action program which included load-scheduling changes, pricing signals to users, plans for a low-head hydroelectric facility to reduce peak loads, and management reorganization. Edmond's officials took the broad, community-wide approach of appointing a citizen advisory committee to make recommendations. The community problem-solving approach has spread to small municipal systems able to draw on local energy and personnel resources. A state-wide program involves utilities in an ad hoc planning committee. (DCK)

  3. A Numerical Study of Thunderstorm Electrification

    DTIC Science & Technology

    1994-01-04

    3460trwofra Rtdum .Prtcjtt M704-011~W18).*4b’r`9’t D~C 20OC3 C. TITLE AND SUBTITLE 5. FUNDING NUMBERS A NUMERICAL STUDY OF THUNDERSTORM ELECTRIFICATION ...Maximum 200 words) The purpose of this research was to pursue further understanding of cloud electrification through three separate projects. First... electrification depends on the time during which strong updrafts remain-within.,the charging’zone. II~b Second, a simple numerical lightning model

  4. Electrification: Mid-term (1985 - 2000)

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Electrification, intended to provide a basis for the mid term period of the energy conservation program, was defined as a set of actions and/or policies that leads to an increasing proportion of total energy used in the form of electricity. The important actions within electrification are those with the greatest impacts (coal and nuclear), the greatest technological requirements (peak shaving and transmission) and the greatest response from the decision makers (economic health and growth of utilities in an era of increasing energy costs). The following areas were discussed: increased power generation from coal action, increased use of nuclear power action, improved operation of public utilities action, actions to be taken in industry, transportation and residential/commercial areas. The various ways in which electrification leads to energy conservation were clarified, and a number of specific recommendations relative to electrification were suggested.

  5. Role of rural electrification in development. [Monograph

    SciTech Connect

    Cecelski, E.; Glatt, S.

    1982-01-01

    The high capital costs of rural-electrification suggest that the assumption that the benefits experienced in developed countries can be duplicated in developing countries is questionable. This review of major issues involved in rural electrification examines the equity side of the socio-economic impacts of major projects in India and Colombia to see if cheap electricity can, with careful planning, become a stimulus for potential entrepreneurs. While the analysis identifies the need for systematic studies to establish the connection between rural electrification and development, the evidence does show that consumption is lower in rural areas both in the amount of electricity used and the percentage of people using it. Direct benefits occur in the productive sector, although the importance of availability and reliability over cost challenges the value of subsidies. Price does appear to be a major factor for small farmers in addition to credit availability and marketing. 45 references, 26 tables. (DCK)

  6. Flow Induced Electrification of Liquid Insulated Systems.

    NASA Astrophysics Data System (ADS)

    Washabaugh, Andrew Patrick

    1995-01-01

    The transport or motion of semi-insulating liquids has led to flow induced static electrification and catastrophic failures in several industries. While techniques for reducing the hazard have been developed, the roles of seemingly important parameters are poorly understood. The objective of this thesis was to measure and understand the fundamental parameters of the flow electrification process that, together with the laws of electroquasistatics and physicochemical hydrodynamics, can be used to predict the performance of complex flow systems, with particular attention to transformer applications. A rotating cylindrical electrode apparatus, which provided cylindrical Couette flow, was used to simulate flow electrification in an electric power transformer. The apparatus had Shell Diala A transformer oil filling the annulus between coaxial cylindrical stainless steel electrodes that were either bare metal, or covered by a thin copper sheet and/or EHV-Weidmann HiVal pressboard insulation. Extensive experiments characterized the time transient and steady state behavior of the electrification through measurements of the volume charge density, the terminal voltage, and the terminal current as the system was driven out of equilibrium by changes in the flow rate (inner cylinder rotation rates of 100-1400 rpm, Reynolds numbers of 5 times 10^3-5 times 10^5), temperature (15-70 ^circ), insulation moisture content (0.5-20 ppm in the oil), applied voltage (0-2 kV DC), and concentration of the non-ionizable anti-static additive 1,2,3 benzotriazole (BTA, 0-60 ppm). Generally, the electrification increased with flow rate and temperature but the BTA appeared to cause competing effects: it decreased the volume charge density on the liquid side of the interface (by a factor of 4), which reduces the electrification, but also decreased the oil conductivity (by a factor of 10), which enhances the electrification. A critical oil BTA concentration of 5 -8 ppm minimized the electrification

  7. Global rural electrification - A different race initiative

    SciTech Connect

    Leonard, R.S. )

    1991-10-01

    The paper considers global rural electrification based on electric power from power stations, built in geosynchronous orbit out of lunar materials. These materials are distributed to individual villages and rural electric cooperatives via microwaves for a cost of about 6-45 cents per kilowatt-hour. Power would be available in modular increments of 25-100 kilowatts with an average capital cost as low as $5000 per kilowatt. The global rural electrification program is aimed at providing electric power from space at competitive costs, relative to current costs, to rural and agricultural areas and diverting resources from weapons development to infrastructure development. 16 refs.

  8. Incubating Innovation for Rural Electrification. Executive Summary

    SciTech Connect

    2013-07-01

    In June, the team held a workshop on ''Low Carbon Sustainable Rural Electrification'' in Salima, Malawi. Co-organized with the Government of Malawi's Department of Energy, this event gathered participants from the energy, telecom, non-profit, banking sectors as well as from governmental and international agencies to discuss the potential development of private led off-grid electrification in Malawi where only 9% of the population has currently access to electricity. A very active participation provided us with insightful feedback and valuable recommendations.

  9. Global rural electrification - A different race initiative

    NASA Astrophysics Data System (ADS)

    Leonard, Raymond S.

    1991-10-01

    The paper considers global rural electrification based on electric power from power stations, built in geosynchronous orbit out of lunar materials. These materials are distributed to individual villages and rural electric cooperatives via microwaves for a cost of about 6-45 cents per kilowatt-hour. Power would be available in modular increments of 25-100 kilowatts with an average capital cost as low as $5000 per kilowatt. The global rural electrification program is aimed at providing electric power from space at competitive costs, relative to current costs, to rural and agricultural areas and diverting resources from weapons development to infrastructure development.

  10. Environmental justification for railroad electrification. Final report

    SciTech Connect

    Bernard, M.J. III; Thorpe, A.B.

    1993-12-01

    In a 1991 workshop, electric utility managers asked the Electric Power Research Institute (EPRI) to address the question of railroad electrification in light of both urban air problems associated with transportation and our national transportation system`s dependence on petroleum fuels. In response, EPRI presents this economic and environmental analysis. This analysis is different from many previous studies in two ways: it determines the capital and operating cost differentials between diesel locomotive trains and electric locomotive trains; it also assigns a dollar value to the environmental costs associated with air pollution from diesel and electric train operations. This study`s purpose is to compare financial costs of rail electrification with environmental costs from air emissions impacts in four case studies: Boston, Chicago, Los Angeles, and San Francisco. These urban regions were chosen because they have different railroad characteristics and they all have air quality problems. This study will present a snapshot of the year 2000 to compare the economics in each region of two scenarios: the rail lines remain diesel power or are electrified. Because of the increase in capital and operating cost, rail electrification is not financially viable in any of these regions. Yet when the benefit of reduced air emissions, typically an {open_quotes}external{close_quotes} value, is included in the analysis, rail electrification may be economically viable.

  11. Shallow cumulus rooted in photosynthesis

    NASA Astrophysics Data System (ADS)

    Vilá-Guerau de Arellano, Jordi; Ouwersloot, Huug G.; Baldocchi, Dennis; Jacobs, Cor M. J.

    2014-03-01

    We study the interactions between plant evapotranspiration, controlled by photosynthesis (C3 and C4 grasses), and moist thermals responsible for the formation of shallow cumulus clouds (SCu). Our findings are based on a series of systematic numerical experiments at fine spatial and temporal scales using large eddy simulations explicitly coupled to a plant-physiology model. The shading provided by SCu leads to strong spatial variability in photosynthesis and the surface energy balance. This in turn results in SCu characterized by less extreme and less skewed values of liquid water path. The larger water use efficiency of C4 grass leads to two opposite effects that influence boundary layer clouds: more vigorous and deeper thermals due to the larger buoyancy surface flux (positive effect) characterized by less moisture content (negative). We find that under these midlatitude and well-watered soil conditions, SCu are characterized by a larger cloud cover and liquid water path over C4 grass fields.

  12. Lessons Learned from NASA UAV Science Demonstration Program Missions

    NASA Technical Reports Server (NTRS)

    Wegener, Steven S.; Schoenung, Susan M.

    2003-01-01

    During the summer of 2002, two airborne missions were flown as part of a NASA Earth Science Enterprise program to demonstrate the use of uninhabited aerial vehicles (UAVs) to perform earth science. One mission, the Altus Cumulus Electrification Study (ACES), successfully measured lightning storms in the vicinity of Key West, Florida, during storm season using a high-altitude Altus(TM) UAV. In the other, a solar-powered UAV, the Pathfinder Plus, flew a high-resolution imaging mission over coffee fields in Kauai, Hawaii, to help guide the harvest.

  13. Atmospheric Electrification in the Solar System

    NASA Astrophysics Data System (ADS)

    Aplin, Karen L.

    2006-01-01

    Atmospheric electrification is not a purely terrestrial phenomenon: all Solar System planetary atmospheres become slightly electrified by cosmic ray ionisation. There is evidence for lightning on Jupiter, Saturn, Uranus and Neptune, and it is possible on Mars, Venus and Titan. Controversy surrounds the role of atmospheric electricity in physical climate processes on Earth; here, a comparative approach is employed to review the role of electrification in the atmospheres of other planets and their moons. This paper reviews the theory, and, where available, measurements, of planetary atmospheric electricity which is taken to include ion production and ion aerosol interactions. The conditions necessary for a planetary atmospheric electric circuit similar to Earth’s, and the likelihood of meeting these conditions in other planetary atmospheres, are briefly discussed. Atmospheric electrification could be important throughout the solar system, particularly at the outer planets which receive little solar radiation, increasing the relative significance of electrical forces. Nucleation onto atmospheric ions has been predicted to affect the evolution and lifetime of haze layers on Titan, Neptune and Triton. Atmospheric electrical processes on Titan, before the arrival of the Huygens probe, are summarised. For planets closer to Earth, heating from solar radiation dominates atmospheric circulations. However, Mars may have a global circuit analogous to the terrestrial model, but based on electrical discharges from dust storms. There is an increasing need for direct measurements of planetary atmospheric electrification, in particular on Mars, to assess the risk for future unmanned and manned missions. Theoretical understanding could be increased by cross-disciplinary work to modify and update models and parameterisations initially developed for a specific atmosphere, to make them more broadly applicable to other planetary atmospheres.

  14. Diesel power leads Yemen electrification plan

    SciTech Connect

    Patarino, C.

    1980-10-01

    The Yemen Arab Republic ended a period of political isolation and is now pushing for social and economic development. A seven-year program announced in 1978 aims to establish and extend rural and urban electrification. A key element in this plan is the construction pf a series of diesel power stations to provide base load until larger steam plants are available in the mid-1980s.

  15. The macroscopic behavior of cumulus ensembles simulated by a cumulus ensemble model

    SciTech Connect

    Kuan-Man Xu; Akio Arakawa; Krueger, S.K. )

    1992-12-15

    The two-dimensional UCLA cumulus ensemble model (CEM), which covers a large horizontal area with a sufficiently small horizontal grid size, is used in this study. A number of simulation experiments are performed with the CEM to study the macroscopic behavior of cumulus convection under a variety of different large-scale and underlying surface conditions. Specifically, the modulation of cumulus activity by the imposed large-scale processes and the eddy kinetic energy (EKE) budget are investigated in detail. In all simulations, cumulus convection is rather strongly modulated by large-scale advective processes in spite of the existence of some nonmodulated high-frequency fluctuations. The modulation exhibits some phase delays, however, when the basic wind shear is strong. This is presumably associated with the existence of mesoscale convective organization. The EKE budget analysis shows that the net eddy buoyancy generation rate is nearly zero for a wide range of cumulus ensembles. 34 refs., 17 figs., 2 tabs.

  16. Surface-Water Quality Assessment of the North Fork Red River Basin Upstream From Lake Altus, Oklahoma, 2002

    DTIC Science & Technology

    2003-01-01

    from Lake Altus, Oklahoma, 2002 CaSO (gypsum, anhydrite) 4 CaCO CaMg(CO ) ( dolomite) 3 3 2 calcite, NaCl (halite) NaHCO3 CALCIUM CHLORIDE SU LF AT E PL...Water Resources Engineering, August 16-17, 1995, San Antonio , Texas: American Society of Civil Engineers, p. 77- 86. Wilde, F.D., and Radtke, D.B., eds

  17. On the Electrification of Pyrocumulus Clouds

    NASA Technical Reports Server (NTRS)

    Lang, Timothy J.; Rutledge, Steven A.; Dolan, Brenda; Krehbiel, Paul; Rison, William; Lindsey, Daniel T.

    2013-01-01

    The electrification (or lack thereof) of pyrocumulus clouds is examined for several different wildfires that occurred during 2012-2013. For example, pyrocumulus clouds above three Colorado wildfires (Hewlett Gulch, High Park, and Waldo Canyon; all occurred during summer 2012) electrified and produced small intracloud discharges whenever the smoke plumes grew to high altitudes (over 10 km above mean sea level, or MSL). This occurred during periods of rapid wildfire growth, as indicated by the shortwave infrared channel on a geostationary satellite, as well as by incident reports. In the Hewlett Gulch case, the fire growth led to increased updrafts within the plume, as inferred by multiple-Doppler radar syntheses, which led to the vertical development and subsequent electrification - a life cycle as short as 30 minutes. The lightning, detected by a three-dimensional lightning mapping network, was favored in high-altitude regions (10 km MSL) containing modest reflectivities (25 dBZ and lower), 0 dB differential reflectivity, and reduced correlation coefficient (0.6-0.7). This indicated the likely presence of ice particles (crystals and aggregates, possibly rimed) mixed with ash. Though neither multiple-Doppler nor polarimetric observations were available during the electrification of the High Park and Waldo Canyon plumes, their NEXRAD observations showed reflectivity structures consistent with Hewlett Gulch. In addition, polarimetric and multiple-Doppler scanning of unelectrified High Park plumes indicated only irregularly shaped ash, and not ice, was present (i.e., reflectivities < 25 dBZ, differential reflectivity > 5 dB, correlation < 0.4), and there was no broaching of the 10 km altitude. Based on these results, the electrification likely was caused by ice-based processes that did not involve significant amounts of graupel. Results for pyrocumulus clouds above notable 2013 wildfires that also experienced rapid growth (e.g., Black Forest, Yarnell Hill, West Fork

  18. Shallow cumulus rooted in photosynthesis

    NASA Astrophysics Data System (ADS)

    Vila-Guerau Arellano, J.; Ouwersloot, H.; Horn, G.; Sikma, M.; Jacobs, C. M.; Baldocchi, D.

    2014-12-01

    We investigate the interaction between plant evapotranspiration, controlled by photosynthesis (for a low vegetation cover by C3 and C4 grasses), and the moist thermals that are responsible for the formation and development of shallow cumulus clouds (SCu). We perform systematic numerical experiments at fine spatial scales using large-eddy simulations explicitly coupled to a plant-physiology model. To break down the complexity of the vegetation-atmospheric system at the diurnal scales, we design the following experiments with increasing complexity: (a) clouds that are transparent to radiation, (b) clouds that shade the surface from the incoming shortwave radiation and (c) plant stomata whose apertures react with an adjustment in time to cloud perturbations. The shading by SCu leads to a strong spatial variability in photosynthesis and the surface energy balance. As a result, experiment (b) simulates SCu that are characterized by less extreme and less skewed values of the liquid water path and cloud-base height. These findings are corroborated by the calculation of characteristics lengths scales of the thermals and clouds using autocorrelation and spectral analysis methods. We find that experiments (a) and (b) are characterized by similar cloud cover evolution, but different cloud population characteristics. Experiment (b), including cloud shading, is characterized by smaller clouds, but closer to each other. By performing a sensitivity analysis on the exchange of water vapor and carbon dioxide at the canopy level, we show that the larger water-use efficiency of C4 grass leads to two opposing effects that directly influence boundary-layer clouds: the thermals below the clouds are more vigorous and deeper driven by a larger buoyancy surface flux (positive effect), but are characterized by less moisture content (negative effect). We conclude that under the investigated mid-latitude atmospheric and well-watered soil conditions, SCu over C4 grass fields is characterized

  19. Rural electrification for development. Policy analysis and application

    SciTech Connect

    Munasinghe, M.

    1986-01-01

    Combining a rigorous analytical framework with actual case studies, the author analyzes the crucial role rural electrification has played in the economic expansion of both developed and developing countries. Governmental resources devoted to the electrification of rural areas have achieved several social and economic goals, such as increased productivity in agriculture, improvements in the quality of rural life, and the augmentation of rural industrialization.

  20. Parameterization of Cumulus Convective Cloud Systems in Mesoscale Forecast Models

    DTIC Science & Technology

    2013-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Parameterization of Cumulus Convective Cloud Systems in...parameterization of cumulus convective clouds in mesoscale numerical weather prediction models OBJECTIVES Conduct detailed studies of cloud ...microphysical processes in order to develop a unified parameterization of boundary layer stratocumulus and trade wind cumulus convective clouds . Develop

  1. (Rural electrification: Grid extension, decentralization, and financing)

    SciTech Connect

    Perlack, R.D.

    1990-02-22

    H.G. (Mike) Jones and I had numerous meetings with EEGSA staff. We discussed rural electrification plans, reviewed documents, and collaborated on collecting information on decentralized energy alternatives. Meetings were also held with USAID/Guatemala, USAID/ROCAP, NRECA, MEM, PVOs, and equipment vendors. A preliminary draft report and spreadsheet for comparing decentralized power alternatives was completed. The report and findings were presented to EEGSA and the methodology transferred to EEGSA staff. A set of recommended followup activities was also presented to EEGSA.

  2. How do aerosols affect storm electrification?

    NASA Astrophysics Data System (ADS)

    Mansell, E. R.

    2009-12-01

    The effects of concentration of cloud condensation nuclei (CCN) on cloud microphysics have long been recognized, but the resultant effects on storm electrification are relatively unexplored. In the present study, a high-resolution 3D model is employed with 2-moment microphysics (hydrometeor mass and number concentration) and electrification and lightning processes. CCN concentration is predicted as a single category monodisperse size spectrum approximating small aerosols. Graupel and hail particle densities are also predicted and are mainly determined by rime density. Rime density in turn is a function of droplet size (affected by CCN concentration) and impact speed. Graupel density is also used as a crude roughness parameter to scale the drag coefficient in the fall speed. A range of CCN concentrations (50 to 2000 cm-3) were tested in two cases of low CAPE (Convective Available Potential Energy) that produced unicell or weakly multicell convection. The TELEX and WK cases have CAPE values of 918 J/kg and 795 J/kg, respectively, and storm lifetimes on the order of 30 to 45 minutes and maximum flash rates of 1 to 16 per minute. Higher CCN concentrations reduced collision-coalescence formation of rain/drizzle, but even at the highest CCN concentrations, the primary process of graupel initiation is through drop freezing. Despite high CCN, vapor supply in the updraft remains sufficient for droplets eventually to grow large enough for coalescence to become appreciable. For both cases, time-integrated volume of graupel (above the freezing level) increases monotonically with increasing CCN, although with different power law relationships (Fig. 1). Time-integrated updraft volume generally increases with greater CCN concentrations, as well, but reached a plateau in the TELEX case for CCN greater than 500 cm-3. Other effects of CCN concentration were variable. In the TELEX case, the greatest electrification (total lightning soures) was for CCN concentrations of 1000 cm-3 and

  3. Lightning parameterization in a storm electrification model

    NASA Technical Reports Server (NTRS)

    Helsdon, John H., Jr.; Farley, Richard D.; Wu, Gang

    1988-01-01

    The parameterization of an intracloud lightning discharge has been implemented in our Storm Electrification Model. The initiation, propagation direction, termination and charge redistribution of the discharge are approximated assuming overall charge neutrality. Various simulations involving differing amounts of charge transferred have been done. The effects of the lightning-produced ions on the hydrometeor charges, electric field components and electrical energy depend strongly on the charge transferred. A comparison between the measured electric field change of an actual intracloud flash and the field change due to the simulated discharge show favorable agreement.

  4. Cumulus convection and the terrestrial water-vapor distribution

    NASA Technical Reports Server (NTRS)

    Donner, Leo J.

    1988-01-01

    Cumulus convection plays a significant role in determining the structure of the terrestrial water vapor field. Cumulus convection acts directly on the moisture field by condensing and precipitating water vapor and by redistributing water vapor through cumulus induced eddy circulations. The mechanisms by which cumulus convection influences the terrestrial water vapor distribution is outlined. Calculations using a theory due to Kuo is used to illustrate the mechanisms by which cumulus convection works. Understanding of these processes greatly aids the ability of researchers to interpret the seasonal and spatial distribution of atmospheric water vapor by providing information on the nature of sources and sinks and the global circulation.

  5. Anomalous scaling of cumulus cloud boundaries

    PubMed

    Siebesma; Jonker

    2000-07-03

    The geometrical properties of cumulus clouds modeled by a numerical technique called large-eddy simulation are investigated. Surface-volume analyses reconfirm previous scaling results based on satellite data. This technique allows for the first time a direct analysis of the scaling behavior of cloud boundaries of individual clouds.

  6. Research on electrostatic electrification during jet kerosene spraying

    NASA Astrophysics Data System (ADS)

    Liu, Quanzhen; Zhang, Wentian; Li, Yipeng; Sun, Keping

    2013-03-01

    Multiple electrostatic electrifications during aircraft fuelling process may cause a fire disaster or explosion, so study on the protection measure for electrostatic electrification is very important for the security of aircraft fuelling. This paper investigated the electrostatic voltage and charge of the fuel nozzle and metal parts during the fuel spraying by self-designed jet kerosene spraying electrostatic electrification test system. The experimental results indicate that the voltage on the fuel nozzle and metal parts is very dangerous for electrostatic safety if they are not reliably grounded.

  7. Satellite Multiangle Cumulus Geometry Retrieval: Case Study

    SciTech Connect

    Kassianov, Evgueni I.; Ackerman, Thomas P.; Marchand, Roger T.; Ovtchinnikov, Mikhail

    2003-02-08

    Most satellite-based analyses have been conducted using near nadir-viewing sensors. The Multi-angle Imaging SpectroRadiometer (MISR), recently launched on the National Aeronautics and Space Administration (NASA) Terra platform, provides high-resolution measurements of reflectance at nine different viewing angles. In this study, we examine the possible retrieval of detailed cumulus geometry using the new and unique MISR datasets. We suggested one approach and apply it to an early MISR dataset of small marine cumulus clouds. This paper also presents validation analysis of this technique with both independent ground-based radar measurements and a model-output inverse problem. Collocated and coincident MISR data and ground-based observations at the Atmospheric Radiation Measurement (ARM) Tropical Western Pacific (TWP) site form the basis of this validation. Future work will attempt to test the suggested approach with additional MISR scenes.

  8. Plume Electrification: Laboratory and Numerical Experiments

    NASA Astrophysics Data System (ADS)

    Mendez, J. S.; Dufek, J.

    2012-12-01

    The spectacular lightning strokes observed during eruptions testify to the enormous potentials that can be generated within plumes. Related to the charging of individual ash particles, large electric fields and volcanic lightning have been observed at Eyjafjallajokull, Redoubt, and Chaiten, among other volcanoes. A number of mechanisms have been proposed for plume electrification, including triboelectric charging, charging from the brittle failure of rock, and charging due to phase change as material is carried aloft. While the overall electrification of the plume likely results from a combination of these processes, in the following work we focus on triboelectric charging—how a plume charges as particles collide with each other. To explore the role of triboelectric effects in plume charging we have conducted a number of small scale laboratory experiments similar to those designed by Forward et al (2009). Succinctly, the experiments consist of fluidizing an ash bed with nitrogen and monitoring the resulting currents induced by the moving particles. It is important to note that the reaction chamber only allows particle-particle interactions. The entire experimental setup is enclosed in a vacuum chamber, allowing us to carefully control the environment during experiments. Runs were carried out for different ash compositions, and driving pressures. We particularly focused on natural grain size distributions of ash and on quantifying not only the net charge but also the charging rate. Furthermore, we report on our progress to incorporate the collected data, namely charging rates, into a large eularian-eularian-lagrangian multiphase eruption dynamic model. Finally, to validate these results, we present our plans to deploy a large wireless sensor network of electrometers and magnetometers around active volcanoes to directly map the overhead E- and M-fields as an eruption occurs.

  9. The Severe Thunderstorm Electrification and Precipitation Study.

    NASA Astrophysics Data System (ADS)

    Lang, Timothy J.; Miller, L. Jay; Weisman, Morris; Rutledge, Steven A.; Barker, Llyle J., III; Bringi, V. N.; Chandrasekar, V.; Detwiler, Andrew; Doesken, Nolan; Helsdon, John; Knight, Charles; Krehbiel, Paul; Lyons, Walter A.; Macgorman, Don; Rasmussen, Erik; Rison, William; Rust, W. David; Thomas, Ronald J.

    2004-08-01

    During May July 2000, the Severe Thunderstorm Electrification and Precipitation Study (STEPS) occurred in the High Plains, near the Colorado Kansas border. STEPS aimed to achieve a better understanding of the interactions between kinematics, precipitation, and electrification in severe thunderstorms. Specific scientific objectives included 1) understanding the apparent major differences in precipitation output from super-cells that have led to them being classified as low precipitation (LP), classic or medium precipitation, and high precipitation; 2) understanding lightning formation and behavior in storms, and how lightning differs among storm types, particularly to better understand the mechanisms by which storms produce predominantly positive cloud-to-ground (CG) lightning; and 3) verifying and improving microphysical interpretations from polarimetric radar. The project involved the use of a multiple-Doppler polarimetric radar network, as well as a time-of-arrival very high frequency (VHF) lightning mapping system, an armored research aircraft, electric field meters carried on balloons, mobile mesonet vehicles, instruments to detect and classify transient luminous events (TLEs; e.g., sprites and blue jets) over thunderstorms, and mobile atmospheric sounding equipment. The project featured significant collaboration with the local National Weather Service office in Goodland, Kansas, as well as outreach to the general public. The project gathered data on a number of different cases, including LP storms, supercells, and mesoscale convective systems, among others. Many of the storms produced mostly positive CG lightning during significant portions of their lifetimes and also exhibited unusual electrical structures with opposite polarity to ordinary thunderstorms. The field data from STEPS is expected to bring new advances to understanding of supercells, positive CG lightning, TLEs, and precipitation formation in convective storms.

  10. Cumulus Cells Block Oocyte Meiotic Resumption via Gap Junctions in Cumulus Oocyte Complexes Subjected to DNA Double-Strand Breaks.

    PubMed

    Sun, Ming-Hong; Zheng, Jie; Xie, Feng-Yun; Shen, Wei; Yin, Shen; Ma, Jun-Yu

    2015-01-01

    During mammalian oocyte growth, genomic DNA may accumulate DNA double-strand breaks (DSBs) induced by factors such as reactive oxygen species. Recent evidence demonstrated that slight DSBs do not activate DNA damage checkpoint proteins in denuded oocytes. These oocytes, even with DNA DSBs, can resume meiosis and progress to metaphase of meiosis II. Meiotic resumption in oocytes is also controlled by the surrounding cumulus cells; accordingly, we analyzed whether cumulus-cell enclosed oocytes (CEOs) with DNA damage are able to resume meiosis. Compared with DNA-damaged denuded oocytes, we found that meiotic resumption rates of CEOs significantly decreased. To assess the mechanism by which cumulus cells block meiotic resumption in CEOs with DNA DSBs, we treated the cumulus oocyte complex with the gap junction inhibitor carbenoxolone and found that carbenoxolone can rescue the block in CEO meiosis induced by DNA DSBs. Since cumulus cell-synthesized cAMPs can pass through the gap junctions between oocyte and cumulus cell to block oocyte meiosis, we measured the expression levels of adenylate cyclase 1 (Adcy1) in cumulus cells, and G-protein coupled receptor 3 (Gpr3) and phosphodiesterase 3A (Pde3a) in oocytes, and found that the mRNA expression level of Adcy1 increased significantly in DNA-damaged cumulus cells. In conclusion, our results indicate that DNA DSBs promote cAMP synthesis in cumulus cells, and cumulus cAMPs can inhibit meiotic resumption of CEOs through gap junctions.

  11. Cumulus cloud formulations for longwave radiation calculations

    SciTech Connect

    Han, D.; Ellingson, R.G.

    1999-03-15

    Longwave radiative transfer under broken cloud conditions is often treated as a problem in cloud bulk geometry, especially for cumulus clouds, because individual clouds are nearly black. However, climate models ignore cloud geometry and estimate the effects of broken cumulus clouds as the cloud amount weighted average of clear and black cloud overcast conditions. To overcome the simplicity of the black plate approximation, the authors developed a more generalized form of cloud geometrical effects on the effective cloud fraction. Following previous work, this form includes parameters that allow a more precise specification of cloud size and spatial distributions. The sensitivity of the generalized form to the variation in cloud bulk geometrical shapes, aspect ratio, size distribution, and side inclination angle are the primary factors significantly affecting the effective cloud fraction. These parameters are important at all cloud amounts with greatest sensitivity when the cloud amount is between 0.2 and 0.8. On the other hand, cloud spatial distributions do not significantly influence the effective cloud fraction when absolute cloud amount is less than 0.2 and/or when the cloud aspect ratio is less than 0.5. However, in the range of greatest sensitivity with large aspect ratio and absolute amount, model comparisons show large intermodel differences. The model discussed herein is cloud size dependent and applies most directly to small cumulus clouds.

  12. Dual effects of hydrogen sulfide donor on meiosis and cumulus expansion of porcine cumulus-oocyte complexes.

    PubMed

    Nevoral, Jan; Petr, Jaroslav; Gelaude, Armance; Bodart, Jean-Francois; Kucerova-Chrpova, Veronika; Sedmikova, Marketa; Krejcova, Tereza; Kolbabova, Tereza; Dvorakova, Marketa; Vyskocilova, Alena; Weingartova, Ivona; Krivohlavkova, Lenka; Zalmanova, Tereza; Jilek, Frantisek

    2014-01-01

    Hydrogen sulfide (H2S) has been revealed to be a signal molecule with second messenger action in the somatic cells of many tissues, including the reproductive tract. The aim of this study was to address how exogenous H2S acts on the meiotic maturation of porcine oocytes, including key maturation factors such as MPF and MAPK, and cumulus expansion intensity of cumulus-oocyte complexes. We observed that the H2S donor, Na2S, accelerated oocyte in vitro maturation in a dose-dependent manner, following an increase of MPF activity around germinal vesicle breakdown. Concurrently, the H2S donor affected cumulus expansion, monitored by hyaluronic acid production. Our results suggest that the H2S donor influences oocyte maturation and thus also participates in the regulation of cumulus expansion. The exogenous H2S donor apparently affects key signal pathways of oocyte maturation and cumulus expansion, resulting in faster oocyte maturation with little need of cumulus expansion.

  13. Airborne observations of electric fields around growing and decaying cumulus clouds

    NASA Technical Reports Server (NTRS)

    Giori, K. L.; Nanevicz, J. E.

    1991-01-01

    Airborne electric field data were gathered in an atmospheric electrification study near Cape Canaveral, FL. A Learjet 36A was instrumented with eight electric field meters (mills) and five different particle probes. The local electric field enhancements at each field mill site were determined under lab conditions and verified using in-flight data. The overdetermined system of eight equations (one for each field mill) was solved using a weighted least squares algorithm to compute the magnitude and direction of the ambient electric field. The signal processing system allowed the measured data to be expressed in terms of earth coordinates, regardless of the attitude of the aircraft. Thus, it was possible to take maximum advantage of the Learjet's speed and maneuverability in studying the electric field structure in the vicinity of the clouds. Data gathered while circling just outside the boundary of a growing cumulus cloud show a nonsymmetric pattern of electric field strength. Field intensity grew rapidly over a period of less than 10 minutes. The observed direction of the ambient electric field vector can be explained by an ascending motion of the charge centers of a classic tripole model of a thunderstorm.

  14. The Relation of the Surface Properties of the Teflons to Frictional Electrification by Polystyrene.

    DTIC Science & Technology

    The friction and frictional electrification properties of Teflon TFE (polytetrafluoroethylene), Teflon PFA (tetrafluoroethylene-perfluoro-(alkyl...constitution of the fluorocarbon surfaces to kinetic coefficient of friction and frictional electrification properties was investigated by using the

  15. Ozone conservation and entrainment in cumulus congestus

    NASA Technical Reports Server (NTRS)

    Pearson, R., Jr.; Weaver, C. J.

    1989-01-01

    This study demonstrates that ozone mixing ratio is conserved during moist convection and can be used as a tracer for cloud entrainment studies. The approach is to apply mixing line analysis to pairs of liquid water potential temperature, total water mixing ratio, O3 and pseudo-equivalent potential temperature derived from aircraft penetrations of growing cumulus congestus. Conclusions about entrainment from the mixing diagrams employing O3 agree with those using thermodynamic quantities. Any disagreement uncovered deficiencies in the water substance measurement technique.

  16. Cumulus cell-expressed type I interferons induce cumulus expansion in mice.

    PubMed

    Jang, You-Jee; Park, Jae-Il; Moon, Won-Jin; Dam, Phuong T M; Cho, Moon-Kyoung; Chun, Sang-Young

    2015-01-01

    Ovulation resembles the inflammatory response. The purpose of the present study was to examine the expression and role of type I interferons (IFNs) Ifnalpha and Ifnbeta in mouse ovaries during the process of ovulation. An in vivo injection of equine chorionic gonadotropin (CG)-human CG (hCG) stimulated Ifnalpha and Ifnbeta mRNA in cumulus-oocyte complexes (COCs) within 6 h. Type I IFN receptor (Ifnar1 and Ifnar2) genes were also expressed in preovulatory follicles without a change by hCG. Immunofluorescent study revealed the expression of protein signals of Ifnalpha, Ifnbeta, and Ifnar1 in cumulus cells. Treatment of COCs with Ifnalpha or Ifnbeta in vitro induced cumulus expansion that was comparable to that mediated by epiregulin. In cultured COCs, the levels of Ifnalpha and Ifnbeta mRNA increased by epiregulin and follicle-stimulating hormone, but not by prostaglandin E2. Ifnalpha and Ifnbeta activated multiple signaling events (signal transducer and activator of transcription-1/3, Akt, and mitogen-activated protein kinase 1/2) and stimulated the expression of genes known to impact COC expansion (Has2, Ptx3, Tnfaip6, and Ptgs2). Interestingly, treatment of COCs with Toll-like receptor (TLR) 2 and TLR4 ligands (lipopolysaccharides, Pam3Cys, and hyaluronan fragments) increased Ifnalpha and Ifnbeta mRNA, while coculture with anti-TLR2/4 neutralizing antibody abolished these effects. Taken together, these results demonstrate that the type I IFN system is operating in mouse cumulus cells and plays a role in the induction of cumulus expansion during the ovulatory process in mice.

  17. A review of thunderstorm electrification processes

    SciTech Connect

    Saunders, C.P.R. )

    1993-04-01

    Recent developments in the area of thunderstorm electrification processes are reviewed. These processes have two main divisions: (a) convective, in which particles charged by ion capture are moved by convection currents to strengthen the electric field in the cloud, and (b) processes involving charge transfer during particle interactions, following which oppositely charged particles move apart in the updraft to form the observed charge centers. Type-b processes are further subdivided into inductive (relying on the preexistence of an electric field) and noninductive charge-transfer mechanisms, Field and laboratory evidence points to the importance of interactions between particles of the ice phase, in the presence of liquid water droplets, in separating electric charge in thunderstorms. Recent experimental studies have investigated the dependence of charge transfer on the size and relative velocity of the interacting particles and have determined the dependence of the sign of the charge transfer on temperature and cloud liquid water content. Field data upon which the laboratory simulations are based are obtained by increasingly sophisticated airborne and ground-based means. Calculations of electric field growth using experimental charge-transfer data in numerical models of the dynamical and microphysical development of thunderstorms show agreement with observations, although further refinement is required. Some directions for future research are outlined. 121 refs., 2 figs.

  18. Oxygen-regulated gene expression in murine cumulus cells.

    PubMed

    Kind, Karen L; Tam, Kimberley K Y; Banwell, Kelly M; Gauld, Ashley D; Russell, Darryl L; Macpherson, Anne M; Brown, Hannah M; Frank, Laura A; Peet, Daniel J; Thompson, Jeremy G

    2015-01-01

    Oxygen is an important component of the environment of the cumulus-oocyte complex (COC), both in vivo within the ovarian follicle and during in vitro oocyte maturation (IVM). Cumulus cells have a key role in supporting oocyte development, and cumulus cell function and gene expression are known to be altered when the environment of the COC is perturbed. Oxygen-regulated gene expression is mediated through the actions of the transcription factors, the hypoxia-inducible factors (HIFs). In the present study, the effect of oxygen on cumulus cell gene expression was examined following in vitro maturation of the murine COC at 2%, 5% or 20% oxygen. Increased expression of HIF-responsive genes, including glucose transporter-1, lactate dehydrogenase A and BCL2/adenovirus E1B interacting protein 3, was observed in cumulus cells matured at 2% or 5%, compared with 20% oxygen. Stabilisation of HIF1α protein in cumulus cells exposed to low oxygen was confirmed by western blot and HIF-mediated transcriptional activity was demonstrated using a transgenic mouse expressing green fluorescent protein under the control of a promoter containing hypoxia response elements. These results indicate that oxygen concentration influences cumulus cell gene expression and support a role for HIF1α in mediating the cumulus cell response to varying oxygen.

  19. Motility contrast imaging of live porcine cumulus-oocyte complexes

    NASA Astrophysics Data System (ADS)

    An, Ran; Turek, John; Machaty, Zoltan; Nolte, David

    2013-02-01

    Freshly-harvested porcine oocytes are invested with cumulus granulosa cells in cumulus-oocyte complexes (COCs). The cumulus cell layer is usually too thick to image the living oocyte under a conventional microscope. Therefore, it is difficult to assess the oocyte viability. The low success rate of implantation is the main problem for in vitro fertilization. In this paper, we demonstrate our dynamic imaging technique called motility contrast imaging (MCI) that provides a non-invasive way to monitor the COCs before and after maturation. MCI shows a change of intracellular activity during oocyte maturation, and a measures dynamic contrast between the cumulus granulosa shell and the oocytes. MCI also shows difference in the spectral response between oocytes that were graded into quality classes. MCI is based on shortcoherence digital holography. It uses intracellular motility as the endogenous imaging contrast of living tissue. MCI presents a new approach for cumulus-oocyte complex assessment.

  20. Contribution of CBX4 to cumulus oophorus cell phenotype in mice and attendant effects in cumulus cell cloned embryos.

    PubMed

    Hao, Lanping; Midic, Uros; Garriga, Judith; Latham, Keith E

    2014-01-15

    Cumulus oophorus cells play an essential role in oocyte development. They are also widely employed as donor cells for cloning by somatic cell nuclear transfer. Our previous studies revealed that Cbx4 mRNA was overexpressed in cloned two-cell embryos. These data indicated that CBX4 may regulate normal cumulus cell differentiation and that its overexpression in clones could contribute to aberrant gene regulation. We used siRNA-mediated knockdown of Cbx4 to assess its role in determining cumulus cell phenotype and compared the effects of this knockdown to published data for aberrant gene regulation in cloned embryos. We observed widespread effects on the expression of genes related to diverse processes in cultured cumulus cells, including cell assembly/proliferation and DNA replication/repair, endocrine function, carbohydrate and lipid metabolism, inflammation, and cell morphology, with apparent effects of CBX4 in promoting cumulus cell proliferation and survival and inhibiting differentiation. Overall, the data implicate CBX4 as a key component in the pathway integrating endocrine signals, intraovarian paracrine factors, and oocyte-derived factors in the control of cumulus cell functions. We also observed altered expression of 25 cumulus cell markers of oocyte quality, indicating an important role of CBX4 in production of high quality oocytes. Finally, we found that about one-quarter of the genes showing aberrant transcription in cloned embryos are sensitive to Cbx4 knockdown in cumulus cells, consistent with a role for aberrant Cbx4 regulation in elaborating abnormal cloned embryo characteristics.

  1. Airport emissions quantification: Impacts of electrification. Final report

    SciTech Connect

    Geba, V.

    1998-07-01

    Four airports were assessed to demonstrate that electrification of economically viable air- and land-side vehicles and equipment can significantly reduce total airport emissions. Assessments were made using the FAA`s Emissions and Dispersion Modeling System and EPRI Airport Electrification Project data. Development and implementation of cost-effective airport emissions reduction strategies can be complex, requiring successful collaboration of local, state, and federal regulatory agencies with airport authorities. The methodology developed in this study helps to simplify this task. The objectives of this study were: to develop a methodology to quantify annual emissions at US airports from all sources--aircraft, vehicles, and infrastructure; and to demonstrate that electrification of economically viable air- and land-side vehicles and equipment can significantly reduce total airport emissions on-site, even when allowing for emissions from the generation of electricity.

  2. Ecuador rural electrification. Project impact evaluation report 21

    SciTech Connect

    Kessler, J.L.; Ballantyne, J.; Maushammer, R.; Simancas, N.R.

    1981-01-01

    The direct and indirect benefits of rural electrification in Ecuador warrant A.I.D.'s continued sponsorship of such programs. This assessment of A.I.D.'s 1964-75 sponsorship of four electrification projects in Ecuador concludes that, although implemented along with other development projects such as road construction, the program was a key factor in upgrading the towns of Santa Elena, Santo Domingo de los Colorados, Daule, and Ambato into regional market and service centers. The main benefits of this program, which was not originally designed to benefit the poor, were job creation, access to agricultural product processing facilities, and increased opportunities for small commercial enterprises.

  3. Connective power: Solar electrification and social change in Kenya

    NASA Astrophysics Data System (ADS)

    Jacobson, Arne Edward

    Household solar photovoltaic systems have emerged as a key alternative to grid-based rural electrification in many developing countries. This may seem a victory for appropriate technology advocates, but my research indicates that the social significance of solar electrification in Kenya, which is among the largest developing country solar markets per capita, is far removed from the classic "small is beautiful" neo-populist vision of building small-scale alternatives to global capitalism. Instead, solar electrification is more closely connected to neo-liberal goals of market-based service provision and economic integration. In this study I combine quantitative and qualitative methods, including surveys, intra-household energy allocation studies, and historical analysis, to analyze the social significance of solar electrification in Kenya. I find that "connective" applications, including television, radio, and cellphones, are centrally important. Television is especially notable; the expansion of TV broadcasting to rural areas was a key condition for solar market development. Solar electricity is also used for lighting. In Kenya, income and work related uses of solar lighting are modest, while education uses are more significant. However, in many households, especially those with small systems, intra-household dynamics constrain key social uses (e.g. children's studying), as the energy is allocated to other uses. Social use patterns combine with access dynamics in Kenya's unsubsidized market to shape the social significance of solar electrification. Solar ownership is dominated by the rural upper and middle classes. Thus, productivity and education uses make small contributions to differentiation and middle class formation. Additionally, solar electrification's role in supporting rural television and radio use improves business advertisers' ability to expand consumer goods markets. These findings link solar electrification to important processes of rural development

  4. Electrification life cycle of incipient thunderstorms

    NASA Astrophysics Data System (ADS)

    Mattos, Enrique V.; Machado, Luiz A. T.; Williams, Earle R.; Goodman, Steven J.; Blakeslee, Richard J.; Bailey, Jeffrey C.

    2017-04-01

    This work evaluates how clouds evolve to thunderstorms in terms of microphysical characteristics to produce the first intracloud (IC) and cloud-to-ground (CG) lightning flashes. Observations of 46 compact isolated thunderstorms during the 2011/2012 spring-summer in Southeast Brazil with an X-band polarimetric radar and two- and three-dimensional Lightning Location Systems demonstrated key parameters in a cloud's vertical structure that produce the initial electrification and lightning activity. The majority (98%) of the first CG flashes were preceded (by approximately 6 min) by intracloud (IC) lightning. The most important aspect of the observations going into this paper, which came originally from the visual examination of a large number of thunderstorms, is that an initial positive differential reflectivity (ZDR) (associated with supercooled raindrops) evolved to reduced ZDR (and even negative values) in the cloud layer between 0° and to -15°C before and during the time of the initial lightning, suggesting evolution from supercooled raindrops to frozen particles promoting the formation of conical graupel. An enhanced negative specific differential phase (KDP) (down to -0.5° km-1) in the glaciated layer (above -40°C) was predominantly observed at the time of the first CG flash, indicating that ice crystals, such as plates and columns, were being vertically aligned by a strong electric field. These results demonstrate that the observations of ZDR evolution in the mixed layer and negative KDP in the upper levels of convective cores may provide useful information on thunderstorm vigor and lightning nowcasting.

  5. Cumulus clouds - Numerical models, observations and entrainment

    NASA Technical Reports Server (NTRS)

    Simpson, J.

    1983-01-01

    The first computer simulation of the organization phase of a buoyant atmospheric thermal is described. Although crude, it showed the spontaneous development of a rounded tight-gradient 'cap' and internal vortical circulation. The complexities involved in these 'field of motion' models in part motivated the development of entity models, based upon laboratory thermals. These one-dimensional models and their uses with observations are briefly described as well as their limitations. Finally, an application of Schlesinger's three-dimensional model to a GATE cumulus situation clarifies many apparently conflicting observations and postulates, thereby raising further challenging questions to be addressed jointly by the more sophisticated measuring and modeling tools available in the 1980's.

  6. Cumulus cloud venting of mixed layer ozone

    NASA Technical Reports Server (NTRS)

    Ching, J. K. S.; Shipley, S. T.; Browell, E. V.; Brewer, D. A.

    1985-01-01

    Observations are presented which substantiate the hypothesis that significant vertical exchange of ozone and aerosols occurs between the mixed layer and the free troposphere during cumulus cloud convective activity. The experiments utilized the airborne Ultra-Violet Differential Absorption Lidar (UV-DIAL) system. This system provides simultaneous range resolved ozone concentration and aerosol backscatter profiles with high spatial resolution. Evening transects were obtained in the downwind area where the air mass had been advected. Space-height analyses for the evening flight show the cloud debris as patterns of ozone typically in excess of the ambient free tropospheric background. This ozone excess was approximately the value of the concentration difference between the mixed layer and free troposphere determined from independent vertical soundings made by another aircraft in the afternoon.

  7. Cloud condensation nuclei near marine cumulus

    NASA Technical Reports Server (NTRS)

    Hudson, James G.

    1993-01-01

    Extensive airborne measurements of cloud condensation nucleus (CCN) spectra and condensation nuclei below, in, between, and above the cumulus clouds near Hawaii point to important aerosol-cloud interactions. Consistent particle concentrations of 200/cu cm were found above the marine boundary layer and within the noncloudy marine boundary layer. Lower and more variable CCN concentrations within the cloudy boundary layer, especially very close to the clouds, appear to be a result of cloud scavenging processes. Gravitational coagulation of cloud droplets may be the principal cause of this difference in the vertical distribution of CCN. The results suggest a reservoir of CCN in the free troposphere which can act as a source for the marine boundary layer.

  8. Cumulus cloud venting of mixed layer ozone

    NASA Technical Reports Server (NTRS)

    Ching, J. K. S.; Shipley, S. T.; Browell, E. V.; Brewer, D. A.

    1985-01-01

    Observations are presented which substantiate the hypothesis that significant vertical exchange of ozone and aerosols occurs between the mixed layer and the free troposphere during cumulus cloud convective activity. The experiments utilized the airborne Ultra-Violet Differential Absorption Lidar (UV-DIAL) system. This system provides simultaneous range resolved ozone concentration and aerosol backscatter profiles with high spatial resolution. Evening transects were obtained in the downwind area where the air mass had been advected. Space-height analyses for the evening flight show the cloud debris as patterns of ozone typically in excess of the ambient free tropospheric background. This ozone excess was approximately the value of the concentration difference between the mixed layer and free troposphere determined from independent vertical soundings made by another aircraft in the afternoon.

  9. Cloud condensation nuclei near marine cumulus

    NASA Technical Reports Server (NTRS)

    Hudson, James G.

    1993-01-01

    Extensive airborne measurements of cloud condensation nucleus (CCN) spectra and condensation nuclei below, in, between, and above the cumulus clouds near Hawaii point to important aerosol-cloud interactions. Consistent particle concentrations of 200/cu cm were found above the marine boundary layer and within the noncloudy marine boundary layer. Lower and more variable CCN concentrations within the cloudy boundary layer, especially very close to the clouds, appear to be a result of cloud scavenging processes. Gravitational coagulation of cloud droplets may be the principal cause of this difference in the vertical distribution of CCN. The results suggest a reservoir of CCN in the free troposphere which can act as a source for the marine boundary layer.

  10. Non-precipitating cumulus cloud study

    SciTech Connect

    Alkezweeny, A.J.

    1984-10-01

    This document describes the field experiment that was conducted in Kentucky during the period from July 20 to August 24, 1983. The objectives were to determine the vertical transport of acidic pollutants by cumulus convection and formation of acidic substances in non-precipitating clouds. The study is a research component of Task Group C (Atmospheric Processes) of the National Acid Precipitation Assessment Program. To examine the vertical transport, an SF/sub 6/ tracer was released from one aircraft, sampled by another aircraft, and sampled on the ground. The results show that pollutants from the boundary layer are lifted to the cloud layer. From there, they are intermittently transported both to the ground and to higher elevations, possibly in the vertical updrafts of towering cumulus clouds. A series of instrumented aircraft flights around the clouds were conducted to study the formation of acidic aerosols. The concentrations of SO/sub 2/, SO/sub 4/, NO/sub 3/, NH/sub 4/, NH/sub 3/, HNO/sub 3/ and trace metals were measured by filter techniques. Furthermore, NO/sub x/, O/sub 3/, light scattering, and basic meteorological parameters were measured in real-time. Detailed chemical composition of aerosols and NH/sub 3/ was also measured on the ground. Preliminary results show that the molar ratio of SO/sub 2//SO/sub 2/ + SO/sub 4/) at cloud tops is higher than at cloud bases. This indicates that sulfate aerosols were formed in the clouds. The NH/sub 3/ concentration shows higher values at nighttime than daytime and decreases sharply with increasing altitude. 3 references.

  11. Oocyte-dependent activation of MTOR in cumulus cells controls the development and survival of cumulus-oocyte complexes.

    PubMed

    Guo, Jing; Shi, Lanying; Gong, Xuhong; Jiang, Mengjie; Yin, Yaoxue; Zhang, Xiaoyun; Yin, Hong; Li, Hui; Emori, Chihiro; Sugiura, Koji; Eppig, John J; Su, You-Qiang

    2016-08-15

    Communication between oocytes and their companion somatic cells promotes the healthy development of ovarian follicles, which is crucial for producing oocytes that can be fertilized and are competent to support embryogenesis. However, how oocyte-derived signaling regulates these essential processes remains largely undefined. Here, we demonstrate that oocyte-derived paracrine factors, particularly GDF9 and GDF9-BMP15 heterodimer, promote the development and survival of cumulus-cell-oocyte complexes (COCs), partly by suppressing the expression of Ddit4l, a negative regulator of MTOR, and enabling the activation of MTOR signaling in cumulus cells. Cumulus cells expressed less Ddit4l mRNA and protein than mural granulosa cells, which is in striking contrast to the expression of phosphorylated RPS6 (a major downstream effector of MTOR). Knockdown of Ddit4l activated MTOR signaling in cumulus cells, whereas inhibition of MTOR in COCs compromised oocyte developmental competence and cumulus cell survival, with the latter likely to be attributable to specific changes in a subset of transcripts in the transcriptome of COCs. Therefore, oocyte suppression of Ddit4l expression allows for MTOR activation in cumulus cells, and this oocyte-dependent activation of MTOR signaling in cumulus cells controls the development and survival of COCs.

  12. Earth Science

    NASA Image and Video Library

    2002-08-01

    A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely piloted aircraft to study thunderstorms in the Atlantic Ocean off Key West and the west of the Everglades. The ACES lightning study used the Altus II twin turbo uninhabited aerial vehicle, built by General Atomics Aeronautical Systems, Inc. of San Diego. The Altus II was chosen for its slow flight speed of 75 to 100 knots (80 to 115 mph), long endurance, and high-altitude flight (up to 65,000 feet). These qualities gave the Altus II the ability to fly near and around thunderstorms for long periods of time, allowing investigations to be conducted over the entire life cycle of storms. The vehicle has a wing span of 55 feet and a payload capacity of over 300 lbs. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the Marshall Space Flight Center, the University of Alabama in Huntsville, NASA's Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

  13. Earth Science

    NASA Image and Video Library

    2002-08-01

    A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely-piloted aircraft to study thunderstorms in the Atlantic Ocean off Key West and the west of the Everglades. The ACES lightning study used the Altus II twin turbo uninhabited aerial vehicle, built by General Atomics Aeronautical Systems, Inc. of San Diego. The Altus II was chosen for its slow flight speed of 75 to 100 knots (80 to 115 mph), long endurance, and high-altitude flight (up to 65,000 feet). These qualities gave the Altus II the ability to fly near and around thunderstorms for long periods of time, allowing investigations to be to be conducted over the entire life cycle of storms. The vehicle has a wing span of 55 feet and a payload capacity of over 300 lbs. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the Marshall Space Flight Center, the University of Alabama in Huntsville, NASA,s Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

  14. Rural electrification in Bangladesh: management, engineering, and financial assessment

    SciTech Connect

    Deverick, B.; Gellerson, M.; Stovall, J.; Shelton, R.

    1986-07-01

    This report represents the partial findings of a five-member, multidisciplinary team requested by USAID to assess the progress of the Rural Electrification Program in Bangladesh. Four areas are assessed in this report: the effectiveness of the management system; the system planning and engineering capabilities; RE tariffs and energy sector pricing policies; and the effectiveness of technical assistance.

  15. Brightness Rural Electrification Program: Renewable Energy in China

    SciTech Connect

    Not Available

    2004-04-01

    Fact sheet describes China's New Brightness Rural Electrification Program to provide electricity for 23 million people in remote areas of China using renewable energy such as wind energy and solar power (photovoltaics). Targets, results, and progress are described. Regions targeted are Inner Mongolia, Tibet, and Gansu.

  16. Contact de-electrification of electrostatically charged polymers.

    PubMed

    Soh, Siowling; Kwok, Sen Wai; Liu, Helena; Whitesides, George M

    2012-12-12

    The contact electrification of insulating organic polymers is still incompletely understood, in part because multiple fundamental mechanisms may contribute to the movement of charge. This study describes a mechanism previously unreported in the context of contact electrification: that is, "contact de-electrification", a process in which polymers charged to the same polarity discharge on contact. Both positively charged polymeric beads, e.g., polyamide 6/6 (Nylon) and polyoxymethylene (Delrin), and negatively charged polymeric beads, e.g., polytetrafluoroethylene (Teflon) and polyamide-imide (Torlon), discharge when the like-charged beads are brought into contact. The beads (both with charges of ∼±20 μC/m(2), or ∼100 charges/μm(2)) discharge on contact regardless of whether they are made of the same material, or of different materials. Discharge is rapid: discharge of flat slabs of like-charged Nylon and Teflon pieces is completed on a single contact (∼3 s). The charge lost from the polymers during contact de-electrification transfers onto molecules of gas in the atmosphere. When like-charged polymers are brought into contact, the increase in electric field at the point of contact exceeds the dielectric breakdown strength of the atmosphere and ionizes molecules of the gas; this ionization thus leads to discharge of the polymers. The detection (using a Faraday cup) of charges transferred to the cup by the ionized gas is compatible with the mechanism. Contact de-electrification occurs for different polymers and in atmospheres with different values of dielectric breakdown strength (helium, argon, oxygen, carbon dioxide, nitrogen, and sulfur hexafluoride): the mechanism thus appears to be general.

  17. Cumulus cloud properties derived using Landsat satellite data

    NASA Technical Reports Server (NTRS)

    Wielicki, B. A.; Welch, R. M.

    1986-01-01

    Landsat Multispectral Scanner (MSS) digital data are used to remotely sense cumulus cloud properties such as cloud fraction and cloud reflectance, along with the distribution of cloud number and cloud fraction as a function of cloud size. The analysis is carried out for four cumulus fields covering regions approximately 150 km square. Results for these initial cloud fields indicate that: (1) the common intuitive model of clouds as nearly uniform reflecting surfaces is a poor representation of cumulus clouds, (2) the cumulus clouds were often multicelled, even for clouds as small as 1 km in diameter, (3) cloud fractional coverage derived using a simple reflectance threshold is sensitive to the chosen threshold even for 57-meter resolution Landsat data, (4) the sensitivity of cloud fraction to changes in satellite sensor resolution is less sensitive than suggested theoretically, and (5) the Landsat derived cloud size distributions show encouraging similarities among the cloud fields examined.

  18. Simulation of solar radiative transfer in cumulus clouds

    SciTech Connect

    Zuev, V.E.; Titov, G.A.

    1996-04-01

    This work presents a 3-D model of radiative transfer which is used to study the relationship between the spatial distribution of cumulus clouds and fluxes (albedo and transmittance) of visible solar radiation.

  19. Determination of the cumulus size distribution from LANDSAT pictures

    NASA Technical Reports Server (NTRS)

    Karg, E.; Mueller, H.; Quenzel, H.

    1983-01-01

    Varying insolation causes undesirable thermic stress to the receiver of a solar power plant. The rapid change of insolation depends on the size distribution of the clouds; in order to measure these changes, it is suitable to determine typical cumulus size distributions. For this purpose, LANDSAT-images are adequate. Several examples of cumulus size distributions will be presented and their effects on the operation of a solar power plant are discussed.

  20. Extracellular Vesicles from Bovine Follicular Fluid Support Cumulus Expansion.

    PubMed

    Hung, Wei-Ting; Hong, Xioman; Christenson, Lane K; McGinnis, Lynda K

    2015-11-01

    Expansion of the cumulus complex surrounding the oocyte is critical for ovulation of a fertilizable egg. The ovulation-inducing surge of luteinizing hormone leads to an increased expression of genes such as prostaglandin-endoperoxide synthase 2 (Ptgs2), pentraxin-related protein 3 (Ptx3), and tumor necrosis factor alpha-induced protein 6 (Tnfaip6) that support cumulus expansion. Factors released by mural granulosa and cumulus granulosa cells into the follicular fluid induce paracrine signaling within the follicular compartment. The follicular fluid that separates these distinct granulosa cell types is an enriched fluid containing numerous proteins, nucleic acids, and other macromolecules. Extracellular vesicles (EVs) are also present; however, no physiologically relevant functions of follicular EVs have yet been demonstrated. In our study, the effect of follicular EVs on cumulus-oocyte complex (COC) expansion and relevant gene expression was assayed. Follicular EVs were isolated using ultracentrifugation from follicular fluid of small (3-5 mm) and large (>9 mm) antral bovine follicles, then characterized by nanoparticle tracking analysis, electron microscopy, and Western blot analysis. To test for bioactivity, mouse and bovine COCs were cultured with follicular EVs. Cumulus expansion and Ptgs2, Ptx3, and Tnfaip6 gene expression were measured following COC maturation culture. The results demonstrated that follicular EVs can support both measurable cumulus expansion and increased gene expression.

  1. Extracellular Vesicles from Bovine Follicular Fluid Support Cumulus Expansion1

    PubMed Central

    Hung, Wei-Ting; Hong, Xioman; Christenson, Lane K.; McGinnis, Lynda K.

    2015-01-01

    Expansion of the cumulus complex surrounding the oocyte is critical for ovulation of a fertilizable egg. The ovulation-inducing surge of luteinizing hormone leads to an increased expression of genes such as prostaglandin-endoperoxide synthase 2 (Ptgs2), pentraxin-related protein 3 (Ptx3), and tumor necrosis factor alpha-induced protein 6 (Tnfaip6) that support cumulus expansion. Factors released by mural granulosa and cumulus granulosa cells into the follicular fluid induce paracrine signaling within the follicular compartment. The follicular fluid that separates these distinct granulosa cell types is an enriched fluid containing numerous proteins, nucleic acids, and other macromolecules. Extracellular vesicles (EVs) are also present; however, no physiologically relevant functions of follicular EVs have yet been demonstrated. In our study, the effect of follicular EVs on cumulus-oocyte complex (COC) expansion and relevant gene expression was assayed. Follicular EVs were isolated using ultracentrifugation from follicular fluid of small (3–5 mm) and large (>9 mm) antral bovine follicles, then characterized by nanoparticle tracking analysis, electron microscopy, and Western blot analysis. To test for bioactivity, mouse and bovine COCs were cultured with follicular EVs. Cumulus expansion and Ptgs2, Ptx3, and Tnfaip6 gene expression were measured following COC maturation culture. The results demonstrated that follicular EVs can support both measurable cumulus expansion and increased gene expression. PMID:26423123

  2. On Trade-wind cumulus cold pools

    NASA Astrophysics Data System (ADS)

    Zuidema, P.; Li, Z.

    2011-12-01

    Shallow, precipitating, cumuli within the easterly trades were investigated using ship-board measurements, scanning radar data, and visible satellite imagery from two weeks in January 2005 of the Rain in Cumulus over Ocean experiment. One focus was to identify the mechanism(s) triggering convection. Shipboard rainfall rates of up to 2 mm hr-1 were recorded almost daily, if only for 10-30 minutes typically, almost always from clouds within mesoscale arcs. The precipitating cumuli, capable of reaching above 4 km, cooled surface air by 1-2 K, in all cases lowered surface specific humidities by up to 1.5 g kg-1, reduced surface equivalent potential temperatures by up to 6 K, and were often associated with short-lived increases in wind speed of up to 4 m s-1. Cohesive downdrafts producing surface air drier than the environment differed from previous observations of moist cold pools under stratocumulus. Upper-level downdrafts were also inferred to explain double-lobed moisture and temperature sounding profiles, as well as multiple inversions in wind profiler data. In two cases investigated further, the precipitating convection propagated faster westward than the mean surface wind by ˜ 2-3 m s-1, consistent with a density current of depth ˜ 200 m. In the cold pool recovery zones of the two cases, the surface air temperatures equilibrated with time to the sea surface temperatures, but the surface air specific humidities stayed relatively constant after initial quick recoveries. This suggested entrainment of drier air from above fully compensated moistening from surface latent heat fluxes as the new surface-based mixed-layer deepened. Recovery zone surface wind speeds and latent heat fluxes were not higher than environmental values. Non-precipitating shallow clouds were observed after the surface buoyancy had sufficiently recovered (barring encroachment of other convection from outside the original cold pool). The mesoscale arcs favored atmospheres with higher water vapor

  3. Electrification pathways for Kenya–linking spatial electrification analysis and medium to long term energy planning

    NASA Astrophysics Data System (ADS)

    Moksnes, Nandi; Korkovelos, Alexandros; Mentis, Dimitrios; Howells, Mark

    2017-09-01

    In September 2015 UN announced 17 Sustainable Development goals (SDG) from which goal number 7 envisions universal access to modern energy services for all by 2030. In Kenya only about 46% of the population currently has access to electricity. This paper analyses hypothetical scenarios, and selected implications, investigating pathways that would allow the country to reach its electrification targets by 2030. Two modelling tools were used for the purposes of this study, namely OnSSET and OSeMOSYS. The tools were soft-linked in order to capture both the spatial and temporal dynamics of their nature. Two electricity demand scenarios were developed representing low and high end user consumption goals respectively. Indicatively, results show that geothermal, coal, hydro and natural gas would consist the optimal energy mix for the centralized national grid. However, in the case of the low demand scenario a high penetration of stand-alone systems is evident in the country, reaching out to approximately 47% of the electrified population. Increasing end user consumption leads to a shift in the optimal technology mix, with higher penetration of mini-grid technologies and grid extension.

  4. First radar echoes from cumulus clouds

    NASA Technical Reports Server (NTRS)

    Knight, Charles A.; Miller, L. J.

    1993-01-01

    In attempting to use centimeter-wavelength radars to investigate the early stage of precipitation formation in clouds, 'mantle echoes' are rediscovered and shown to come mostly from scattering by small-scale variations in refractive index, a Bragg kind of scattering mechanism. This limits the usefulness of single-wavelength radar for studies of hydrometeor growth, according to data on summer cumulus clouds in North Dakota, Hawaii, and Florida, to values of reflectivity factor above about 10 dBZe with 10-cm radar, 0 dBZe with 5-cm radar, and -10 dBZe with 3-cm radar. These are limits at or above which the backscattered radar signal from the kinds of clouds observed can be assumed to be almost entirely from hydrometeors or (rarely) other particulate material such as insects. Dual-wavelength radar data can provide the desired information about hydrometeors at very low reflectivity levels if assumptions can be made about the inhomogeneities responsible for the Bragg scattering. The Bragg scattering signal itself probably will be a useful way to probe inhomogeneities one-half the radar wavelength in scale for studying cloud entrainment and mixing processes. However, this use is possible only before scattering from hydrometeors dominates the radar return.

  5. Cumulus cloud transport of transient tracers

    NASA Technical Reports Server (NTRS)

    Gidel, L. T.

    1983-01-01

    A theoretical framework is developed for including cumulus cloud transport, rainout of water soluble gases, and aqueous phase chemistry into gas phase photochemical models. Cloud populations are represented as ensemble distributions of individual clouds of various heights. An individual cloud is represented as a one-dimensional, steady state plume with height-independent radius entraining air from the boundary of the cloud. The model is applied to several hypothetical atmospheric tracers to show how clouds may affect the tropospheric distributions of ozone, NO(y), SO2, peroxyacetylnitrate, hydrocarbons, and other gases. Although the numerical experiments were based on cloud mass fluxes from diagnostic studies in the tropics and thus are not representative of the entire globe, it was found that an increasing mixing ratio with height in the free troposphere can be produced for some gases with only a surface source when clouds are present. This suggests that some reactive tropospheric species with primarily surface sources may play a somewhat more important role in tropospheric chemistry than is presently believed depending on the global distribution of cloud mass fluxes. Deficiencies in existing photochemical models due to the way clouds are typically treated are discussed.

  6. Protection of cumulus cells following dehydroepiandrosterone supplementation.

    PubMed

    Lin, Li-Te; Wang, Peng-Hui; Chen, San-Nung; Li, Chia-Jung; Wen, Zhi-Hong; Cheng, Jiin-Tsuey; Tsui, Kuan-Hao

    2017-02-01

    Growing studies have demonstrated that dehydroepiandrosterone (DHEA) may improve fertility outcomes in poor ovarian responders (PORs). The aim of this study was to compare clinical outcomes and cumulus cell (CC) expression before and after DHEA treatment in PORs undergoing in vitro fertilization (IVF) cycles. Six patients with poor ovarian response were enrolled in the study according to Bologna criteria. DHEA was supplied at least 2 months before patients entered into the next IVF cycle. Expression of apoptosis-related genes in CCs was determined by quantitative real-time PCR. Mitochondrial dehydrogenase activity of CCs was assessed by cell counting kit-8 assay. Metaphase II oocytes, maturation rate, embryos at Day 3, and fertilization rate significantly increased following DHEA treatment. Expression of cytochrome c, caspase 9, and caspase 3 genes in CCs were significantly reduced after DHEA therapy. Additionally, increased mitochondrial activity of CCs was observed following DHEA supplementation. DHEA supplementation may protect CCs via improved mitochondrial activity and decreased apoptosis, leading to better clinical outcomes in PORs.

  7. Transcriptomic analysis of cyclic AMP response in bovine cumulus cells.

    PubMed

    Khan, D R; Guillemette, C; Sirard, M A; Richard, F J

    2015-09-01

    Acquisition of oocyte developmental competence needs to be understood to improve clinical outcomes of assisted reproduction. The stimulation of cumulus cell concentration of cyclic adenosine 3'5'-monophosphate (cAMP) by pharmacological agents during in vitro maturation (IVM) participates in improvement of oocyte quality. However, precise coordination and downstream targets of cAMP signaling in cumulus cells are largely unknown. We have previously demonstrated better embryo development after cAMP stimulation for first 6 h during IVM. Using this model, we investigated cAMP signaling in cumulus cells through in vitro culture of cumulus-oocyte complexes (COCs) in the presence of cAMP raising agents: forskolin, IBMX, and dipyridamole (here called FID treatment). Transcriptomic analysis of cumulus cells indicated that FID-induced differentially expressed transcripts were implicated in cumulus expansion, steroidogenesis, cell metabolism, and oocyte competence. Functional genomic analysis revealed that protein kinase-A (PKA), extracellular signal regulated kinases (ERK1/2), and calcium (Ca(2+)) pathways as key regulators of FID signaling. Inhibition of PKA (H89) in FID-supplemented COCs or substitution of FID with calcium ionophore (A23187) demonstrated that FID activated primarily the PKA pathway which inhibited ERK1/2 phosphorylation and was upstream of calcium signaling. Furthermore, inhibition of ERK1/2 phosphorylation by FID supported a regulation by dual specific phosphatase (DUSP1) via PKA. Our findings imply that cAMP (FID) regulates cell metabolism, steroidogenesis, intracellular signaling and cumulus expansion through PKA which modulates these functions through optimization of ERK1/2 phosphorylation and coordination of calcium signaling. These findings have implications for development of new strategies for improving oocyte in vitro maturation leading to better developmental competence.

  8. Electrification and Charge Distribution in Vertically Shaken Granular Media

    NASA Astrophysics Data System (ADS)

    Rojas, Ruben; Nordsiek, Freja; Lathrop, Daniel

    2016-11-01

    Granular charging of particle laden flows at large scales is a widespread phenomenon and has long been observed in nature: Volcanic ash clouds, desert sandstorms, dust devils, thunderstorms and snowstorms all undergo electrification at large scale. As a first approach to understand this phenomenon, we confined granular particles to a vertically oscillating cylindrical chamber with top and bottom conducting plates. Long term voltage transients between the plates and a high dependence on the total particle surface area suggested the preponderance of collective effects in the electrification processes. In order to further explore this hypothesis, we reduced the electrode area for the measurement with two 2-cm circular flat probes on the top plate. With this setup we detected differences in the charge distribution among the particles due to a more localized measurement of the voltage. This research was supported by the Julian Schwinger Foundation.

  9. The use of photovoltaics for rural electrification in northwestern China

    SciTech Connect

    Wallace, W.L.; Li Jingming; Gao Shangbin

    1998-09-01

    The use of renewable energy technologies in China is becoming increasingly important to meet the needs of a large rural population. Solar and wind renewable resources in particular are available in regions of China that at present have no access to conventional grid power. Two regions in China that have an acute lack of electricity are a large region in northern and western China and the coastal island region of China. These regions have attracted the attention of the Chinese government in terms of increasing the quality of life and standard of living conditions of the rural population. These regions have also attracted the attention of domestic Chinese companies and of international companies, governments, and multilateral development organizations as a potential market for renewable energy rural electrification systems. This paper focuses on the bilateral cooperation between the US Department of Energy and China in providing assistance for the use of renewable technologies for rural electrification in northwestern China.

  10. Efficient System Design and Sustainable Finance for China's Village Electrification Program: Preprint

    SciTech Connect

    Ma, S.; Yin, H.; Kline, D. M.

    2006-08-01

    This paper describes a joint effort of the Institute for Electrical Engineering of the Chinese Academy of Sciences (IEE), and the U.S. National Renewable Energy Laboratory (NREL) to support China's rural electrification program. This project developed a design tool that provides guidelines both for off-grid renewable energy system designs and for cost-based tariff and finance schemes to support them. This tool was developed to capitalize on lessons learned from the Township Electrification Program that preceded the Village Electrification Program. We describe the methods used to develop the analysis, some indicative results, and the planned use of the tool in the Village Electrification Program.

  11. Final Report - Navajo Electrification Demonstration Project - FY2004

    SciTech Connect

    Kenneth L. Craig, Interim General Manager

    2007-03-31

    The Navajo Electrification Demonstration Project (NEDP) is a multi-year projects which addresses the needs of unserved Navajo Nation residents without basic electricity services. The Navajo Nation is the United States' largest tribe, in terms of population and land. An estimated 18,000 Navajo Nation homes do not have basic grid-tied electricity--and this third year of funding, known as NEDP-3, provided 351 power line extensions to Navajo families.

  12. Shorepower Truck Electrification Project (STEP) - Cumulative through June 2014

    SciTech Connect

    2014-08-01

    The Fleet Test and Evaluation Team at the U.S. Department of Energy's National Renewable Energy Laboratory is evaluating and documenting the use of shorepower at 50 planned American Recovery and Reinvestment Act (ARRA)-funded truck stop electrification (TSE) sites across the nation. Trucks participating in the study have idle-reduction equipment installed that was purchased with rebates through the ARRA. A total of 5,000 rebates will be approved.

  13. Shorepower Truck Electrification Project (STEP) - 2013 (Fact Sheet)

    SciTech Connect

    Not Available

    2014-01-01

    The Fleet Test and Evaluation Team at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is evaluating and documenting the use of shorepower at 50 planned American Recovery and Reinvestment Act (ARRA)-funded truck stop electrification sites across the nation. Trucks participating in the study have idle-reduction equipment installed that was purchased with rebates through the ARRA. A total of 5,000 rebates will be approved.

  14. Shorepower Truck Electrification Project (STEP) - Cumulative through February 2015

    SciTech Connect

    2015-02-01

    The Fleet Test and Evaluation Team at the U.S. Department of Energy's National Renewable Energy Laboratory is evaluating and documenting the use of shorepower at 50 planned American Recovery and Reinvestment Act (ARRA)-funded truck stop electrification sites across the nation. Trucks participating in the study have idle-reduction equipment installed that was purchased with rebates through the ARRA. A total of 5,000 rebates will be approved.

  15. Thundercloud electrification models in atmospheric electricity and meteorology

    NASA Technical Reports Server (NTRS)

    Parker, L. W.

    1980-01-01

    A survey is presented of presently-available theoretical models. The models are classified into three main groups: (1) convection models, (2) precipitation models, and (3) general models. The strengths and weaknesses of the models, their dimensionalities and degrees of sophistication, the nature of their inputs and outputs, and the various specific charging mechanisms treated by them, are considered. In results obtained to date, the convection models predict no significant electrification enhancement based on conductivity gradients and convection alone, with the assumed air circulation patterns. Results of the precipitation models show that the initial electrification can occur rapidly and stably through noninductive collision mechanisms involving ice, and breakdown-strength electric fields can relatively easily be achieved subsequently through the collisional-inductive mechanism. A critical difficulty of the collision mechanisms is imprecise knowledge of relaxation times versus contact times, which can easily lead to overestimates of electrification. The general model results tend to support those of the precipitation models in emphasizing the high potential effectiveness of the collisional-inductive mechanism.

  16. Surface-water quality assessment of the North Fork Red River basin upstream from Lake Altus, Oklahoma, 2002

    USGS Publications Warehouse

    Smith, S. Jerrod; Schneider, M.L.; Masoner, J.R.; Blazs, R.L.

    2003-01-01

    Elevated salinity in the North Fork Red River is a major concern of the Bureau of Reclamation W. C. Austin Project at Lake Altus. Understanding the relation between surface-water runoff, ground-water discharge, and surface-water quality is important for maintaining the beneficial use of water in the North Fork Red River basin. Agricultural practices, petroleum production, and natural dissolution of salt-bearing bedrock have the potential to influence the quality of nearby surface water. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation, sampled stream discharge and water chemistry at 19 stations on the North Fork Red River and tributaries. To characterize surface-water resources of the basin in a systematic manner, samples were collected synoptically during receding streamflow conditions during July 8-11, 2002. Together, sulfate and chloride usually constitute greater than half of the dissolved solids. Concentrations of sulfate ranged from 87.1 to 3,450 milligrams per liter. The minimum value was measured at McClellan Creek near Back (07301220), and the maximum value was measured at Bronco Creek near Twitty (07301303). Concentrations of chloride ranged from 33.2 to 786 milligrams per liter. The minimum value was measured at a North Fork Red River tributary (unnamed) near Twitty (07301310), and the maximum value was measured at the North Fork Red River near Back (07301190), the most upstream sample station.

  17. Satellite-tracked cumulus velocities. [for determining wind velocity

    NASA Technical Reports Server (NTRS)

    Fujita, T. T.; Pearl, E. W.; Shenk, W. E.

    1973-01-01

    The research indicates that extreme caution must be exercised in converting cloud velocities into winds. The motion of fair-weather cumuli obtained by tracking their shadows over Springfield, Missouri revealed that the standard deviation in the individual cloud motion is several times the tracking error. The motion of over-ocean cumuli near Barbados clearly indicated the complicated nature of cumulus velocities. Analysis of whole-sky images obtained near Tampa, Florida failed to show significant continuity and stability of cumulus plumes, less than 0.3 mile in diameter. Cumulus turrets with 0.3 to 2 mile in size appear to be the best target to infer the mean wind within the subcloud layers. Cumulus or stratocumulus cells consisting of x number of turrets do not always move with wind. The addition and deletion of turrets belonging to a specific cell appear to be the cause of the erratic motion of a tracer cell. It may by concluded that the accuracy of wind estimates is unlikely to be better than 2m/sec unless the physical and dynamical characteristics of cumulus motion is futher investigated.

  18. Seeding cumulus in Florida: new 1970 results.

    PubMed

    Simpson, J; Woodley, W L

    1971-04-09

    In the Florida single cloud experiments, the main result of the statistical analyses is that the dynamic seeding effect on rainfall is large, positive, and significant. From all the 1968 and 1970 data together, the seeding effect is estimated to be larger than a factor of 3; that is, the seeded clouds rained more than three times as much as the controls after the seeding run. On fair days, defined objectively by percentage of area covered by showers, the seeding effect is shown to be larger than the overall average, but it may be negative on rainy days. Rainy days in the tropics are about 10 percent of the days with rain, but they produce about half the total rainfall. The applicability of our single cloud results to other areas is not established but seems hopeful for many tropical and subtropical regions. It can be assessed by cloud population studies together with our numerical model (25). Guidance for the next steps toward practical rainfall enhancement and toward the understanding and modification of cloud systems in storms may be provided by our study of merger clouds. Mergers are shown often to produce more than an order of magnitude more rain than isolated clouds on the same day, probably owing to dynamic invigoration of the merged cloud circulations. Results of our first small attempt toward inducing and documenting mergers in a multiple cloud seeding experiment appear promising. Although far from statistically conclusive, they have opened a new frontier in the science and technology of dynamic cloud modification. It is also hoped that the multiple cumulus seeding experiments will help to clarify the formation of "cloud clusters" and their role in large-scale circulations, thus contributing to the focal subject of the Global Atmospheric Research Program in the tropics.

  19. Cell-to-cell communication and ovulation. A study of the cumulus-oocyte complex

    PubMed Central

    1978-01-01

    Cell-to-cell communication was characterized in cumulus-oocyte complexes from rat ovarian follicles before and after ovulation. Numerous, small gap junctional contacts were present between cumulus cells and oocytes before ovulation. The gap junction are formed on the oocyte surface by cumulus cell processes that transverse the zona pellucida and contact the oolemma. The entire cumulus mass was also connected by gap junctions via cumulus-cumulus interactions. In the hours preceding ovulation, the frequency of gap junctional contacts between cumulus cells and the oocyte was reduced, and the cumulus was disorganized. Electrophysiological measurements indicated that bidirectional ionic coupling was present between the cumulus and oocyte before ovulation. In addition, iontophoretically injected fluorescein dye was tranferred between the oocyte and cumulus cells. Examination of the extent of ionic coupling in cumulus-oocyte specimens before and after ovulation revealed that ionic coupling between the cumulus and oocyte progressively decreased as the time of ovulation approached. In postovulatory specimens, no coupling was detected. Although some proteolytic mechanism may be involved in the disintegration of the cumulus-oocyte complex, neither the cumulus cells nor the oocyte produced detectable levels of plasminogen activator, a protease which is synthesized by membrana granulosa cells. In summary, cell communication is a characterisitc feature of the cumulus-oocyte complex, and this communication is terminated near the time of ovulation. This temporal pattern of the termination of communication between the cumulus and the oocyte may indicate that communication provides a mechanism for regulating the maturation of the oocyte during follicular development before ovulation. PMID:670298

  20. On the cumulus diurnal cycle over the tropical warm pool

    NASA Astrophysics Data System (ADS)

    Ruppert, James H.; Johnson, Richard H.

    2016-06-01

    An idealized cloud-resolving model experiment is executed to study the prominent cumulus diurnal cycle in suppressed regimes over the tropical warm pool. These regimes are characterized by daytime cumulus invigoration and cloud-layer moistening connected with enhanced diurnal cycles in shortwave radiative heating (SW) and sea surface temperature (SST). The relative roles of diurnally varying SW and SST in this cumulus diurnal cycle are assessed, wherein radiation is modeled and SST is prescribed. Large-scale subsidence is parameterized using the spectral weak temperature gradient (WTG) scheme, such that large-scale vertical motion (wwtg), and hence subsidence drying, is modulated by diurnal changes in diabatic heating. A control simulation exhibits daytime cumulus invigoration that closely matches observations, including midday cloud-layer moistening. This cumulus invigoration is composed of two distinct modes: (1) a midday nonprecipitating ("forced") mode of predominately shallow clouds, driven by the peak in SST and surface fluxes as the mixed layer deepens and dries; and (2) a precipitating late-afternoon ("active") mode characterized by deeper clouds in connection with a more moist cloud layer. This cloud-layer moistening is driven by the daytime relaxation of wwtg subsidence, which is prompted by the midday peak in SW. The transition from the surface flux-driven forced mode to the active precipitating mode is accompanied by a transition from relatively small-scale boundary layer circulation cells to larger cells that are highly modulated by cold pools, consistent with observations. When the diurnal cycle is removed, clouds are persistently shallower with virtually no rainfall, emphasizing the inherent nonlinearity of the cumulus diurnal cycle.

  1. The beneficial effects of cumulus cells and oocyte-cumulus cell gap junctions depends on oocyte maturation and fertilization methods in mice

    PubMed Central

    Zhou, Cheng-Jie; Wu, Sha-Na; Shen, Jiang-Peng; Wang, Dong-Hui; Kong, Xiang-Wei; Lu, Angeleem; Li, Yan-Jiao; Zhou, Hong-Xia; Zhao, Yue-Fang

    2016-01-01

    Cumulus cells are a group of closely associated granulosa cells that surround and nourish oocytes. Previous studies have shown that cumulus cells contribute to oocyte maturation and fertilization through gap junction communication. However, it is not known how this gap junction signaling affects in vivo versus in vitro maturation of oocytes, and their subsequent fertilization and embryonic development following insemination. Therefore, in our study, we performed mouse oocyte maturation and insemination using in vivo- or in vitro-matured oocyte-cumulus complexes (OCCs, which retain gap junctions between the cumulus cells and the oocytes), in vitro-matured, denuded oocytes co-cultured with cumulus cells (DCs, which lack gap junctions between the cumulus cells and the oocytes), and in vitro-matured, denuded oocytes without cumulus cells (DOs). Using these models, we were able to analyze the effects of gap junction signaling on oocyte maturation, fertilization, and early embryo development. We found that gap junctions were necessary for both in vivo and in vitro oocyte maturation. In addition, for oocytes matured in vivo, the presence of cumulus cells during insemination improved fertilization and blastocyst formation, and this improvement was strengthened by gap junctions. Moreover, for oocytes matured in vitro, the presence of cumulus cells during insemination improved fertilization, but not blastocyst formation, and this improvement was independent of gap junctions. Our results demonstrate, for the first time, that the beneficial effect of gap junction signaling from cumulus cells depends on oocyte maturation and fertilization methods. PMID:26966678

  2. The beneficial effects of cumulus cells and oocyte-cumulus cell gap junctions depends on oocyte maturation and fertilization methods in mice.

    PubMed

    Zhou, Cheng-Jie; Wu, Sha-Na; Shen, Jiang-Peng; Wang, Dong-Hui; Kong, Xiang-Wei; Lu, Angeleem; Li, Yan-Jiao; Zhou, Hong-Xia; Zhao, Yue-Fang; Liang, Cheng-Guang

    2016-01-01

    Cumulus cells are a group of closely associated granulosa cells that surround and nourish oocytes. Previous studies have shown that cumulus cells contribute to oocyte maturation and fertilization through gap junction communication. However, it is not known how this gap junction signaling affects in vivo versus in vitro maturation of oocytes, and their subsequent fertilization and embryonic development following insemination. Therefore, in our study, we performed mouse oocyte maturation and insemination using in vivo- or in vitro-matured oocyte-cumulus complexes (OCCs, which retain gap junctions between the cumulus cells and the oocytes), in vitro-matured, denuded oocytes co-cultured with cumulus cells (DCs, which lack gap junctions between the cumulus cells and the oocytes), and in vitro-matured, denuded oocytes without cumulus cells (DOs). Using these models, we were able to analyze the effects of gap junction signaling on oocyte maturation, fertilization, and early embryo development. We found that gap junctions were necessary for both in vivo and in vitro oocyte maturation. In addition, for oocytes matured in vivo, the presence of cumulus cells during insemination improved fertilization and blastocyst formation, and this improvement was strengthened by gap junctions. Moreover, for oocytes matured in vitro, the presence of cumulus cells during insemination improved fertilization, but not blastocyst formation, and this improvement was independent of gap junctions. Our results demonstrate, for the first time, that the beneficial effect of gap junction signaling from cumulus cells depends on oocyte maturation and fertilization methods.

  3. Advancing Models and Evaluation of Cumulus, Climate and Aerosol Interactions

    SciTech Connect

    Gettelman, Andrew

    2015-10-27

    This project was successfully able to meet its’ goals, but faced some serious challenges due to personnel issues. Nonetheless, it was largely successful. The Project Objectives were as follows: 1. Develop a unified representation of stratifom and cumulus cloud microphysics for NCAR/DOE global community models. 2. Examine the effects of aerosols on clouds and their impact on precipitation in stratiform and cumulus clouds. We will also explore the effects of clouds and precipitation on aerosols. 3. Test these new formulations using advanced evaluation techniques and observations and release

  4. Historical evidence that electrification caused the 20th century epidemic of "diseases of civilization".

    PubMed

    Milham, Samuel

    2010-02-01

    The slow spread of residential electrification in the US in the first half of the 20th century from urban to rural areas resulted by 1940 in two large populations; urban populations, with nearly complete electrification and rural populations exposed to varying levels of electrification depending on the progress of electrification in their state. It took until 1956 for US farms to reach urban and rural non-farm electrification levels. Both populations were covered by the US vital registration system. US vital statistics tabulations and census records for 1920-1960, and historical US vital statistics documents were examined. Residential electrification data was available in the US census of population for 1930, 1940 and 1950. Crude urban and rural death rates were calculated, and death rates by state were correlated with electrification rates by state for urban and rural areas for 1940 white resident deaths. Urban death rates were much higher than rural rates for cardiovascular diseases, malignant diseases, diabetes and suicide in 1940. Rural death rates were significantly correlated with level of residential electric service by state for most causes examined. I hypothesize that the 20th century epidemic of the so called diseases of civilization including cardiovascular disease, cancer and diabetes and suicide was caused by electrification not by lifestyle. A large proportion of these diseases may therefore be preventable.

  5. Navajo Electrification for Sustainable Development: The Potential Economic and Social Benefits

    ERIC Educational Resources Information Center

    Ballentine, Crystal; DeSouza, Anil; Bain, Craig; Majure, Lisa; Smith, Dean Howard; Turek, Jill

    2004-01-01

    The concomitant secondary consequences of an electrification program and the potential long-term benefits of such a program are described. An electrification program can stimulate a move toward true self-determination and self-sufficiency for the Navajo nation.

  6. Individual and community quality of life in the era of electrification in Indonesia

    NASA Astrophysics Data System (ADS)

    Kusuma, Sugiyanto Eddie

    This study examines the extent to which electrification relates to improvement of quality of life in Indonesia. In this respect, the study addresses two objectives. First, it examines the extent to which electrification accounts for differences in quality of life in Indonesia. Second, it assesses the extent to which rural-urban locations account for differences in the effects of electrification, human capital, social capital, and physical capital on quality of life. Drawing from the 1993 Indonesian Family Life Survey (IFLS), quality of life was defined as child survivability. The results indicated that access to electricity played an important role in enhancing quality of life for both rural and urban communities. Electrification, human capital, and social capital were important factors for quality of life in rural communities. For urban communities, key factors were electrification, human capital, social capital, and physical capital.

  7. Semiprognostic tests of the Arakawa-Schubert cumulus parameterization using simulated data

    NASA Technical Reports Server (NTRS)

    Xu, Kuan-Man; Arakawa, Akio

    1992-01-01

    Semiprognostic tests are performed against data simulated by a cumulus ensemble model to evaluate the Arakawa-Schubert (A-S) cumulus parametrization. It is found that the A-S cumulus parametrization is generally valid despite the existence of mesoscale organization in cumulus convection. The nondiagnostic and nondeterministic aspects of the A-S cumulus parametrization are examined by testing the sensitivity of the parametrization to the horizontal grid resolution. It is also shown that the inclusion of convective-scale downdrafts improves the results of semiprognostic tests.

  8. Cumulus clouds - Early aircraft observations and entrainment hypotheses

    NASA Technical Reports Server (NTRS)

    Simpson, J.

    1983-01-01

    The history of cumulus research in the decade following World War II is reviewed in the perspective of the new ideas and advances made during the subsequent generation. Emphasis is placed upon pioneering aircraft measurements, evidence for entrainment, the early model attempts and their attendant controversies.

  9. Evaluation of a New Parameterization for Fair-Weather Cumulus

    SciTech Connect

    Berg, Larry K.; Stull, Roland B.

    2006-05-25

    A new parameterization for boundary layer cumulus clouds, called the cumulus potential (CuP) scheme, is introduced. This scheme uses joint probability density functions (JPDFs) of virtual potential temperature and water-vapor mixing ratio, as well as the mean vertical profiles of virtual potential temperature, to predict the amount and size distribution of boundary layer cloud cover. This model considers the diversity of air parcels over a heterogeneous surface, and recognizes that some parcels rise above their lifting condensation level to become cumulus, while other parcels might rise as clear updrafts. This model has several unique features: 1) surface heterogeneity is represented using the boundary layer JPDF of virtual potential temperature versus water-vapor mixing ratio, 2) clear and cloudy thermals are allowed to coexist at the same altitude, and 3) a range of cloud-base heights, cloud-top heights, and cloud thicknesses are predicted within any one cloud field, as observed. Using data from Boundary Layer Experiment 1996 and a model intercomparsion study using large eddy simulation (LES) based on Barbados Oceanographic and Meteorological Experiment (BOMEX), it is shown that the CuP model does a good job predicting cloud-base height and cloud-top height. The model also shows promise in predicting cloud cover, and is found to give better cloud-cover estimates than three other cumulus parameterizations: one based on relative humidity, a statistical scheme based on the saturation deficit, and a slab model.

  10. Recirculation and growth of raindrops in simulated shallow cumulus

    NASA Astrophysics Data System (ADS)

    Naumann, A. K.; Seifert, A.

    2016-06-01

    This study investigates growth processes of raindrops and the role of recirculation of raindrops for the formation of precipitation in shallow cumulus. Two related cases of fields of lightly precipitating shallow cumulus are simulated using Large-Eddy Simulation combined with a Lagrangian drop model for raindrop growth and a cloud tracking algorithm. Statistics from the Lagrangian drop model yield that most raindrops leave the cloud laterally and then evaporate in the subsaturated cloud environmental air. Only 1%-3% of the raindrops contribute to surface precipitation. Among this subsample of raindrops that contribute to surface precipitation, two growth regimes are identified: those raindrops that are dominated by accretional growth from cloud water, and those raindrops that are dominated by selfcollection among raindrops. The mean cloud properties alone are not decisive for the growth of an individual raindrop but the in-cloud variability is crucial. Recirculation of raindrops is found to be common in shallow cumulus, especially for those raindrops that contribute to surface precipitation. The fraction of surface precipitation that is attributed to recirculating raindrops differs from cloud to cloud but can be larger than 50%. This implies that simple conceptual models of raindrop growth that neglect the effect of recirculation disregard a substantial portion of raindrop growth in shallow cumulus.

  11. Bolivia: rural electrification. Project impact evaluation report No. 16

    SciTech Connect

    Butler, E.; Poe, K.M.; Tendler, J.

    1980-12-01

    Two rural electrification systems initiated in Bolivia in 1973 and 1974 are the subject of this report. By 1979, all distribution networks were completed, except in the La Paz region. Power was supplied to 42,000 consumers and was used primarily for residential lighting. Although demand outpaced supply, consumption per household was lower than projected, and irrigation and industrial use was negligible. The preponderant positive impact of the projects was social. Household lighting improved the physical quality of life for 7% of Bolivia's rural population.

  12. User-owned utility models for rural electrification

    SciTech Connect

    Waddle, D.

    1997-12-01

    The author discusses the history of rural electric cooperatives (REC) in the United States, and the broader question of whether such organizations can serve as a model for rural electrification in other countries. The author points out the features of such cooperatives which have given them stability and strength, and emphasizes that for success of such programs, many of these same features must be present. He definitely feels the cooperative models are not outdated, but they need strong local support, and a governmental structure which is supportive, and in particular not negative.

  13. The Green Ocean Over the Amazon: Implications for Cloud Electrification

    NASA Technical Reports Server (NTRS)

    Williams, E.; Blakeslee, R.; Boccippio, D.; Arnold, James E. (Technical Monitor)

    2001-01-01

    A convective regime with distinct maritime characteristics (weak updraft, low CCN, prevalent coalescence and rainout, weak mixed phase reflectivity, low glaciation temperature, and little if any lightning) is documented over the Amazon basin of the South American continent, and dubbed the "green ocean". Radar, lightning, thermodynamic and AVHRR satellite observations are examined to shed light on the roles of updraft and aerosol in providing departures from the green ocean regime toward continental behavior. Extreme case studies are identified in which the updraft control is dominant and in which the aerosol control is dominant. The tentative conclusion gives importance to both updrafts and aerosol in shaping the electrification of tropical convection.

  14. Shorepower Truck Electrification Project (STEP) - 1Q - 2Q 2013

    SciTech Connect

    2014-02-01

    The Fleet Test and Evaluation Team at the U.S. Department of Energy's National Renewable Energy Laboratory is evaluating and documenting the use of shorepower at 50 planned American Recovery and Reinvestment Act (ARRA)-funded truck stop electrification (TSE) sites across the nation. Trucks participating in the study have idle-reduction equipment installed that was purchased with rebates through the ARRA. A total of 5,000 rebates will be approved. the ARRA. A total of 5,000 rebates will be approved.

  15. Does Electrification Spur the Fertility Transition? Evidence From Indonesia.

    PubMed

    Grimm, Michael; Sparrow, Robert; Tasciotti, Luca

    2015-10-01

    We analyze various pathways through which access to electricity affects fertility in Indonesia, using a district difference-in-difference approach. The electrification rate increased by 65 % over the study period, and our results suggest that the subsequent effects on fertility account for about 18 % to 24 % of the overall decline in fertility. A key channel is increased exposure to television. Using in addition several waves of Demographic and Health Surveys, we find suggestive evidence that increased exposure to TV affects, in particular, fertility preferences and increases the effective use of contraception. Reduced child mortality seems to be another important pathway.

  16. The Green Ocean Over the Amazon: Implications for Cloud Electrification

    NASA Technical Reports Server (NTRS)

    Williams, E.; Blakeslee, R.; Boccippio, D.; Arnold, James E. (Technical Monitor)

    2001-01-01

    A convective regime with distinct maritime characteristics (weak updraft, low CCN, prevalent coalescence and rainout, weak mixed phase reflectivity, low glaciation temperature, and little if any lightning) is documented over the Amazon basin of the South American continent, and dubbed the "green ocean". Radar, lightning, thermodynamic and AVHRR satellite observations are examined to shed light on the roles of updraft and aerosol in providing departures from the green ocean regime toward continental behavior. Extreme case studies are identified in which the updraft control is dominant and in which the aerosol control is dominant. The tentative conclusion gives importance to both updrafts and aerosol in shaping the electrification of tropical convection.

  17. Cumulus parameterizations in chemical transport models

    NASA Astrophysics Data System (ADS)

    Mahowald, Natalie M.; Rasch, Philip J.; Prinn, Ronald G.

    1995-12-01

    Global three-dimensional chemical transport models (CTMs) are valuable tools for studying processes controlling the distribution of trace constituents in the atmosphere. A major uncertainty in these models is the subgrid-scale parametrization of transport by cumulus convection. This study seeks to define the range of behavior of moist convective schemes and point toward more reliable formulations for inclusion in chemical transport models. The emphasis is on deriving convective transport from meteorological data sets (such as those from the forecast centers) which do not routinely include convective mass fluxes. Seven moist convective parameterizations are compared in a column model to examine the sensitivity of the vertical profile of trace gases to the parameterization used in a global chemical transport model. The moist convective schemes examined are the Emanuel scheme [Emanuel, 1991], the Feichter-Crutzen scheme [Feichter and Crutzen, 1990], the inverse thermodynamic scheme (described in this paper), two versions of a scheme suggested by Hack [Hack, 1994], and two versions of a scheme suggested by Tiedtke (one following the formulation used in the ECMWF (European Centre for Medium-Range Weather Forecasting) and ECHAM3 (European Centre and Hamburg Max-Planck-Institut) models [Tiedtke, 1989], and one formulated as in the TM2 (Transport Model-2) model (M. Heimann, personal communication, 1992). These convective schemes vary in the closure used to derive the mass fluxes, as well as the cloud model formulation, giving a broad range of results. In addition, two boundary layer schemes are compared: a state-of-the-art nonlocal boundary layer scheme [Holtslag and Boville, 1993] and a simple adiabatic mixing scheme described in this paper. Three tests are used to compare the moist convective schemes against observations. Although the tests conducted here cannot conclusively show that one parameterization is better than the others, the tests are a good measure of the

  18. Ground-Based Remote Retrievals of Cumulus Entrainment Rates

    SciTech Connect

    Wagner, Timothy J.; Turner, David D.; Berg, Larry K.; Krueger, Steven K.

    2013-07-26

    While fractional entrainment rates for cumulus clouds have typically been derived from airborne observations, this limits the size and scope of available data sets. To increase the number of continental cumulus entrainment rate observations available for study, an algorithm for retrieving them from ground-based remote sensing observations has been developed. This algorithm, called the Entrainment Rate In Cumulus Algorithm (ERICA), uses the suite of instruments at the Southern Great Plains (SGP) site of the United States Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility as inputs into a Gauss-Newton optimal estimation scheme, in which an assumed guess of the entrainment rate is iteratively adjusted through intercomparison of modeled liquid water path and cloud droplet effective radius to their observed counterparts. The forward model in this algorithm is the Explicit Mixing Parcel Model (EMPM), a cloud parcel model that treats entrainment as a series of discrete entrainment events. A quantified value for measurement uncertainty is also returned as part of the retrieval. Sensitivity testing and information content analysis demonstrate the robust nature of this method for retrieving accurate observations of the entrainment rate without the drawbacks of airborne sampling. Results from a test of ERICA on three months of shallow cumulus cloud events show significant variability of the entrainment rate of clouds in a single day and from one day to the next. The mean value of 1.06 km-¹ for the entrainment rate in this dataset corresponds well with prior observations and simulations of the entrainment rate in cumulus clouds.

  19. Sino/American cooperation for rural electrification in China

    SciTech Connect

    Wallace, W.L.; Tsuo, Y.S.

    1997-02-01

    Rapid growth in economic development, coupled with the absence of an electric grid in large areas of the rural countryside, have created a need for new energy sources both in urban centers and rural areas in China. There is a very large need for new sources of energy for rural electrification in China as represented by 120 million people in remote regions who do not have access to an electric grid and by over 300 coastal islands in China that are unelectrified. In heavily populated regions in China where there is an electric grid, there are still severe shortages of electric power and limited access to the grid by village populations. In order to meet energy demands in rural China, renewable energy in the form of solar, wind, and biomass resources are being utilized as a cost effective alternative to grid extension and use of diesel and gasoline generators. An Energy Efficiency and Renewable Energy Protocol Agreement was signed by the U.S. Department of Energy with the Chinese State Science and Technology Commission in Beijing in February, 1995. Under this agreement, projects using photovoltaics for rural electrification are being conducted in Gansu Province in western China and Inner Mongolia in northern China, providing the basis for much wider deployment and use of photovoltaics for meeting the growing rural energy demands of China. {copyright} {ital 1997 American Institute of Physics.}

  20. Photovoltaics for rural electrification in the Dominican Republic

    SciTech Connect

    Hansen, R.D.; Martin, J.G.

    1987-08-21

    Enersol Associates, Inc., has begun to structure a program for the introduction of photovoltaics in rural areas, and started to refer to this as the SOBASEC (SOlar-BASed Rural Electrification Concept) program. Throughout the report we have used the acronym SOBASEC to refer to the specific approach to electrification in rural areas with photovoltaics, as developed by Enersol Associates, Inc. This report documents the efforts to date and describes SOBASEC so that a variety of readers may benefit. This report provides an overall background on the Dominican Republic and a history of the project developed by Enersol in the Puerto Plata region. It describes the electric grid system that is owned and operated by the Dominican Government, and which serves urban dwellers and approximately 30% of the rural population. This paper is dedicated to describing the technical and institutional details of SOBASEC as developed by experience in implementing the program and installing the first 100 PV systems. Also discussed is the logical expansion that can take place with adequate financing and institutional support. This is done by describing a reasonable investment scenario. A key catalytic role of this financing is placed in the hands of the organizations that aim toward economic and social development in less developed countries. Recommendations and concluding comments on where this all may lead in the years to come is finally discussed. 61 refs., 59 figs.

  1. Joint U.S./Brazilian Renewable Energy Rural Electrification Project

    SciTech Connect

    Taylor, R.W.; Leboeuf, C.; Moszkowicz, M.; Valente, L.G.

    1994-12-31

    The Joint US/Brazilian Renewable Energy Rural Electrification Project was established following the Earth Summit in Rio de Janeiro in June 1992. Installation of the hardware for Phase 1 of the project has been completed; the nearly 800 photovoltaic (PV) lighting systems are now operational, and a 3-year period of monitored operating and maintenance experience has begun. Procurement for equipment in a Phase 2 project expansion into 6 additional states was completed during the summer of 1994. In Phase 2, the project emphasis has expanded into other applications (water pumping by both PV ad wind, stand-aloe home electrification with basic ac power, two 50-kW village-scale hybrid power systems for diesel fuel displacement in the amazon Basin, and additional home, school, and health clinic dc power systems). The objectives of these pilot projects are to establish technical, institutional, and economic confidence in using renewable energy (PV and wind) system to meet the needs of the citizens of rural Brazil.

  2. Expression of focal adhesion kinase in mouse cumulus-oocyte complexes, and effect of phosphorylation at Tyr397 on cumulus expansion.

    PubMed

    Ohtake, Jun; Sakurai, Masahiro; Hoshino, Yumi; Tanemura, Kentaro; Sato, Eimei

    2015-03-01

    We investigated the expression of focal adhesion kinase (FAK) in mouse cumulus-oocyte complexes (COCs), as well as the role of FAK phosphorylation at Tyr397 during oocyte maturation. The effect of inhibiting FAK phosphorylation at Tyr397 during in vitro maturation (IVM) on subsequent fertilization and preimplantation embryo development was also examined. Western blotting analyses revealed that total and Tyr397-phosphorylated FAK were expressed in vivo in both cumulus cells and oocytes. Immunocytochemical studies localized this kinase throughout the cytoplasm of cumulus cells and oocytes; in particular, Tyr397-phosphorylated FAK tended to accumulate in regions where cumulus cells contact each other. Interestingly, the in vivo level of Tyr397 phosphorylation in cumulus cells was significantly lower after compared to before cumulus expansion. Addition of FAK inhibitor 14, which specifically blocks phosphorylation at Tyr397, stimulated oocyte meiotic maturation and cumulus expansion during IVM in the absence of follicle-stimulating hormone (FSH). Reverse-transcriptase PCR showed that the mRNA expression of hyaluronan synthase 2 (Has2), a marker of cumulus expansion, was significantly induced in cumulus cells. Subsequent in vitro fertilization and culture showed that more oocytes developed to the blastocyst stage when they were treated with FAK inhibitor 14 during IVM, although the blastocyst total cell number was lower than in oocytes stimulated with FSH. These results indicate that FAK is involved in the maturation of COCs; specifically, phosphorylation at Tyr397 may regulate cumulus expansion via the expression of Has2 mRNA in cumulus cells, which could affect the developmental competence of oocytes.

  3. Cooperative effects of 17β-estradiol and oocyte-derived paracrine factors on the transcriptome of mouse cumulus cells.

    PubMed

    Emori, Chihiro; Wigglesworth, Karen; Fujii, Wataru; Naito, Kunihiko; Eppig, John J; Sugiura, Koji

    2013-12-01

    Oocyte-derived paracrine factors (ODPFs) and estrogens are both essential for the development and function of ovarian follicles in mammals. Cooperation of these two factors was assessed in vitro using intact cumulus-oocyte complexes, cumulus cells cultured after the removal of oocytes [oocytectomized (OOX) cumulus cells], and OOX cumulus cells cocultured with denuded oocytes, all in the presence or absence of 17β-estradiol (E2). Effects on the cumulus cell transcriptome were assessed by microarray analysis. There was no significant difference between the cumulus cell transcriptomes of either OOX cumulus cells cocultured with oocytes or intact cumulus-oocyte complexes. Therefore, oocyte-mediated regulation of the cumulus cell transcriptome is mediated primarily by ODPFs and not by gap junctional communication between oocytes and cumulus cells. Gene ontology analysis revealed that both ODPFs and E2 strongly affected the biological processes associated with cell proliferation in cumulus cells. E2 had limited effects on ODPF-regulated biological processes. However, in sharp contrast, ODPFs significantly affected biological processes regulated by E2 in cumulus cells. For example, only in the presence of ODPFs did E2 significantly promote the biological processes related to phosphorylation-mediated signal transduction in cumulus cells, such as the signaling pathways of epidermal growth factor, vascular endothelial growth factor, and platelet-derived growth factor. Therefore, ODPFs and E2 cooperate to regulate the cumulus cell transcriptome and, in general, oocytes modulate the effects of estrogens on cumulus cell function.

  4. Electrification : A New Approach To Evaluate Slip Velocity During Flow Instabilities

    NASA Astrophysics Data System (ADS)

    Flores, Fabrice; Allal, Ahmed; Guerret-Piècourt, Christelle

    2007-04-01

    The original feature of this work consists in the parallel study, in extrusion, of the polymer electrification and flow instabilities. On one hand, the Mhetar and Archer model has been used to predict the evolution of slip velocity versus shear stress and on the other hand, the double layer theory seem to be the better theory to explain electrification. We have shown that electrification measurements allow us to measure the slip velocity. The slip velocity values calculated via double layer theory are consistent with those calculated with the Methar and Archer model and allow us to validate our approach. The conclusion is that it's possible to determine the slip velocity during flow instabilities.

  5. A New Scheme for Predicting Fair-Weather Cumulus

    SciTech Connect

    Berg, Larry K.; Stull, Roland B.

    2007-04-01

    A new parameterization for boundary layer cumulus clouds, called the cumulus potential (CuP) scheme, is introduced. Unlike many other parameterizations, the CuP scheme explicitly links the fair-weather clouds to the boundary-layer turbulence and accounts for the non-local nature of the turbulence. This scheme uses joint probability density functions (JPDFs) of virtual potential temperature and water-vapor mixing ratio, as well as the mean vertical profiles of virtual potential temperature, to predict the amount and size distribution of boundary layer cloud cover. This model considers the diversity of air parcels over a heterogeneous surface, and recognizes that some parcels rise above their lifting condensation level to become cumulus, while other parcels might rise as clear updrafts. This model has several unique features: 1) surface heterogeneity and boundary-layer turbulence is represented using the boundary layer JPDF of virtual potential temperature versus water-vapor mixing ratio, 2) clear and cloudy thermals are allowed to coexist at the same altitude, and 3) a range of cloud-base heights, cloud-top heights, and cloud thicknesses are predicted within any one cloud field, as observed. Using data from Boundary Layer Experiment 1996 and a model intercomparsion study using large eddy simulation (LES) based on the Barbados Oceanographic and Meteorological Experiment (BOMEX), the CuP scheme is compared to three other cumulus parameterizations: one based on relative humidity, a statistical scheme based on the saturation deficit, and a slab model. It is shown that the CuP model does a better job predicting the cloud-base height and the cloud-top height than three other parameterizations. The model also shows promise in predicting cloud cover, and is found to give better cloud-cover estimates than the three other cumulus parameterizations. In ongoing work supported by the US Department of Energy¹s Atmospheric Radiation Measurement Program, the CuP scheme is being

  6. The importance of having zinc during in vitro maturation of cattle cumulus-oocyte complex: role of cumulus cells.

    PubMed

    Anchordoquy, J M; Anchordoquy, J P; Sirini, M A; Picco, S J; Peral-García, P; Furnus, C C

    2014-10-01

    The aim of this study was to investigate the influence of zinc (Zn) on the health of cumulus-oocyte complex (COC) during in vitro maturation (IVM). Experiments were designed to evaluate the effect of Zn added to IVM medium on: DNA integrity, apoptosis, cumulus expansion and superoxide dismutase (SOD) activity of cumulus cells (CC). Also, role of CC on Zn transport during IVM was evaluated on oocyte developmental capacity. DNA damage and early apoptosis were higher in CC matured with 0 μg/ml Zn compared with 0.7, 1.1 and 1.5 μg/ml Zn (p < 0.05). Cumulus expansion did not show differences in COC matured with or without Zn supplementation (p > 0.05). Superoxide dismutase activity was higher in COC matured with 1.5 μg/ml Zn than with 0 μg/ml Zn (p < 0.05). Cleavage and blastocyst rates were recorded after IVM in three maturation systems: intact COCs, denuded oocytes with cumulus cells monolayer (DO + CC) and denuded oocytes (DO). Cleavage rates were similar when COC, DO + CC or DO were matured with 1.5 μg/ml Zn compared with control group (p > 0.05). Blastocyst rates were significantly higher in COC than in DO + CC and DO with the addition of 1.5 μg/ml Zn during IVM (p < 0.01). Blastocyst quality was enhanced in COC and DO + CC compared with DO when Zn was added to IVM medium (p < 0.001). The results of this study indicate that Zn supplementation to IVM medium (i) decreased DNA damage and apoptosis in CC; (ii) increased SOD activity in CC; (iii) did not modify cumulus expansion and cleavage rates after in vitro fertilization; (iv) improved subsequent embryo development up to blastocyst stage; and (v) enhanced blastocyst quality when CC were present either in intact COC or in coculture during IVM.

  7. Cumulus and granulosa cell markers of oocyte and embryo quality

    PubMed Central

    Uyar, Asli; Torrealday, Saioa; Seli, Emre

    2013-01-01

    Lack of an objective, accurate, and noninvasive embryo assessment strategy remains one of the major challenges encountered in in vitro fertilization. Cumulus and mural granulosa cells reflect the characteristics of the oocyte, providing a noninvasive means to assess oocyte quality. Specifically, transcriptomic profiling of follicular cells may help identify biomarkers of oocyte and embryo competence. Current transcriptomics technologies include quantitative reverse transcriptase–polymerase chain reaction (qRT-PCR) for analysis of individual genes and microarrays and high-throughput deep sequencing for whole genome expression profiling. Recently, using qRT-PCR and microarray technologies, a multitude of studies correlated changes in cumulus or granulosa cell gene expression with clinically relevant outcome parameters, including in vitro embryo development and pregnancy. While the initial findings are promising, a clinical benefit from the use of identified biomarker genes remains to be demonstrated in randomized controlled trials. PMID:23498999

  8. Stabilization functions of unforced cumulus clouds - Their nature and components

    NASA Technical Reports Server (NTRS)

    Ramirez, Jorge A.; Bras, Rafael L.; Emanuel, Kerry A.

    1990-01-01

    The nature and the spatial distribution of cumuli within an unforced cumulus cloud field are investigated. The thermodynamic effects of convection are quantified as functions of changes of convective available potential energy (CAPE) induced by the convective overturning, and the time rate of change of CAPE is parameterized in terms of a kernel of influence or stabilization function. A three-dimensional cloud model is used to infer and quantify stabilization functions by performing single-cloud experiments. On the basis of the results obtained, a new hypothesis with respect to the spatial distribution of cumuli is postulated, which states that, under completely homogeneous external conditions and assuming a spatially random distribution of cloud-triggering mechanisms, the spatial distribution of cumuli in the resulting cloud field must be regular, as opposed to either random or clustered, because cumulus clouds tend to reduce the available energy for convection, thereby inhibiting further convection nearby.

  9. Influence of fair-weather cumulus clouds on isoprene chemistry

    NASA Astrophysics Data System (ADS)

    Kim, S.-W.; Barth, M. C.; Trainer, M.

    2012-05-01

    Fair-weather cumulus clouds are not resolved in regional- and global-scale atmospheric chemistry models because their horizontal extent is less than the horizontal resolution of the model. A Large-Eddy Simulation (LES) model, with finer grid resolution, can resolve the energy containing turbulent eddies and fair-weather cumulus clouds. Isoprene, which is mainly emitted from deciduous forests and plays a significant role in producing ozone, has a chemical lifetime similar to the boundary layer turbulence turnover time, indicating that turbulent transport, cloud processes, and chemistry are all potentially important for the prediction of ambient isoprene concentrations. The LES model coupled with chemistry developed in this study is an ideal tool to examine the influence of fair-weather cumulus clouds on isoprene chemistry. With a LES model that includes a moderately complex gas-phase chemical mechanism of isoprene oxidation, we find enhancement of isoprene, methacrolein, and methylvinyl ketone in the cloud layer while changes in these chemical species' mixing ratios in the subcloud layer relative to the cloud-free case vary depending on the chemical lifetimes. We demonstrate that nitrogen oxides put into the system can modulate the chemical lifetimes of isoprene and related chemical species, which in turn changes the vertical distribution of the chemical species. For high NOx conditions, ozone in the subcloud layer for the cloudy case is ˜5 ppbv lower than that for the cloud-free case, suggesting potential positive ozone bias in large-scale models that do not include fair-weather cumulus cloud processes.

  10. Continuous growth of cloud droplets in cumulus cloud

    NASA Astrophysics Data System (ADS)

    Gotoh, Toshiyuki; Suehiro, Tamotsu; Saito, Izumi

    2016-04-01

    A new method to seamlessly simulate the continuous growth of droplets advected by turbulent flow inside a cumulus cloud was developed from first principle. A cubic box ascending with a mean updraft inside a cumulus cloud was introduced and the updraft velocity was self-consistently determined in such a way that the mean turbulent velocity within the box vanished. All the degrees of freedom of the cloud droplets and turbulence fields were numerically integrated. The box ascended quickly inside the cumulus cloud due to the updraft and the mean radius of the droplets grew from 10 to 24 μm for about 10 min. The turbulent flow tended to slow down the time evolutions of the updraft velocity, the box altitude and the mean cloud droplet radius. The size distribution of the cloud droplets in the updraft case was narrower than in the absence of the updraft. It was also found that the wavenumeber spectra of the variances of the temperature and water vapor mixing ratio were nearly constant in the low wavenumber range. The future development of the new method was argued.

  11. Entrainment in Laboratory Simulations of Cumulus Cloud Flows

    NASA Astrophysics Data System (ADS)

    Narasimha, R.; Diwan, S.; Subrahmanyam, D.; Sreenivas, K. R.; Bhat, G. S.

    2010-12-01

    A variety of cumulus cloud flows, including congestus (both shallow bubble and tall tower types), mediocris and fractus have been generated in a water tank by simulating the release of latent heat in real clouds. The simulation is achieved through ohmic heating, injected volumetrically into the flow by applying suitable voltages between diametral cross-sections of starting jets and plumes of electrically conducting fluid (acidified water). Dynamical similarity between atmospheric and laboratory cloud flows is achieved by duplicating values of an appropriate non-dimensional heat release number. Velocity measurements, made by laser instrumentation, show that the Taylor entrainment coefficient generally increases just above the level of commencement of heat injection (corresponding to condensation level in the real cloud). Subsequently the coefficient reaches a maximum before declining to the very low values that characterize tall cumulus towers. The experiments also simulate the protected core of real clouds. Cumulus Congestus : Atmospheric cloud (left), simulated laboratory cloud (right). Panels below show respectively total heat injected and vertical profile of heating in the laboratory cloud.

  12. Runaway Electrification of Friable Self-Replicating Granular Matter

    PubMed Central

    2013-01-01

    We establish that the nonlinear dynamics of collisions between particles favors the charging of an insulating, friable, self-replicating granular material that undergoes nucleation, growth, and fission processes; we demonstrate with a minimal dynamical model that secondary nucleation produces a positive feedback in an electrification mechanism that leads to runaway charging. We discuss ice as an example of such a self-replicating granular material: We confirm with laboratory experiments in which we grow ice from the vapor phase in situ within an environmental scanning electron microscope that charging causes fast-growing and easily breakable palmlike structures to form, which when broken off may form secondary nuclei. We propose that thunderstorms, both terrestrial and on other planets, and lightning in the solar nebula are instances of such runaway charging arising from this nonlinear dynamics in self-replicating granular matter. PMID:24041221

  13. Rural cooperatives: Information on two rural electrification administration proposals

    SciTech Connect

    Not Available

    1986-01-01

    In response to the Rural Electrification Administration's proposal to eliminate its engineering standards divisions, GAO found that (1) the advantages of retaining REA's technical standards-setting functions far exceed the disadvantages; (2) adopting and applying industry standards would not be an acceptable alternative to REA's standards; (3) it would be impractical for REA to impose a fee to all users of its engineering standards but a fee charged to the cooperatives, as a percent of the loans they receive, appears practical; (4) abolishing all technical standards would have an adverse effect on REA's program to assist rural utilities; and (5) approved staffing pattern for both standards divisions stayed at the same level from FY 1983 to FY 1985. GAO also responded to REA's proposal to revise its criteria for loans and advances.

  14. Indonesia solar home systems project for rural electrification

    SciTech Connect

    Sanghvi, A.P.

    1997-12-01

    This paper presents, from a financing aspect the broad issues involved in a plan to provide solar home systems (SHS) to provide rural electrification in several areas of rural Indonesia. The paper discusses the approaches being used to provide funding, develop awareness of the technology, and assure the success of the project. The plan involves the use of grant money to help with some of the initial costs of such systems, and thereby to encourage local financing on a terms rather than cash basis. There are needs for market development, and development of a business structure in the country to support this type of technology. Provided this plan can succeed, it may serve as a model for further efforts.

  15. Electrohydrodynamic generation of millimetric drops and control of electrification

    NASA Astrophysics Data System (ADS)

    Yun, Sungchan

    2017-07-01

    We report a simple method for millimetric drop generation by electrohydrodynamic (EHD) detachment using a conventional nozzle-ring device. The EHD detachment method provides distinct features of uniform-size and controlled electrification of millimetric drops. The drop dynamics of detachment and shape oscillation are recorded using a high-speed camera and analyzed for several dc voltages applied to the electrode. Experimental studies show that an oscillation frequency can be closely related to the amount of electric charge, which can be explained based on both effective interfacial tension and inviscid Rayleigh and Lamb frequency. Furthermore, we present a concept to generate a neutral drop by adjusting the duration time of a pulse signal and discuss a drop oscillation induced by the detachment. This study can provide potential implications for drop manipulation, such as transporting, merging, and mixing, in microfluidic platforms.

  16. An intracloud lightning parameterization scheme for a storm electrification model

    NASA Technical Reports Server (NTRS)

    Helsdon, John H., Jr.; Wu, Gang; Farley, Richard D.

    1992-01-01

    The parameterization of an intracloud lightning discharge has been implemented in the present storm electrification model. The initiation, propagation direction, and termination of the discharge are computed using the magnitude and direction of the electric field vector as the determining criteria. The charge redistribution due to the lightning is approximated assuming the channel to be an isolated conductor with zero net charge over its entire length. Various simulations involving differing amounts of charge transferred and distribution of charges have been done. Values of charge transfer, dipole moment change, and electrical energy dissipation computed in the model are consistent with observations. The effects of the lightning-produced ions on the hydrometeor charges and electric field components depend strongly on the amount of charge transferred. A comparison between the measured electric field change of an actual intracloud flash and the field change due to the simulated discharge shows favorable agreement. Limitations of the parameterization scheme are discussed.

  17. Rural areas electrification (Latin America), Guatemala City, Guatemala, June 4--7, 1989: Foreign trip report

    SciTech Connect

    Katzman, M.T.

    1989-01-01

    ORNL serves the function of monitoring the Central American Rural Electrification Support Program (CARES) of US Agency for International Development (USAID), which is administered by NRECA. The results of the Demand Assessment Model, presented at the conference, were reviewed, and a paper on the use of marginal cost analysis for rural electrification was delivered for presentation by NRECA staff. Discussions on the acceptability of the model were discussed with utility representatives.

  18. Further Research on the Electrification of Pyrocumulus Clouds

    NASA Technical Reports Server (NTRS)

    Lang, Timothy J.; Laroche, Kendell; Baum, Bryan; Bateman, Monte; Mach, Douglas

    2015-01-01

    Past research on pyrocumulus electrification has demonstrated that a variety of lightning types can occur, including cloud-to-ground (CG) flashes, sometimes of dominant positive polarity, as well as small intra-cloud (IC) discharges in the upper levels of the pyro-cloud. In Colorado during summer 2012, the first combined polarimetric radar, multi-Doppler radar, and three-dimensional lightning mapping array (LMA) observations of lightning-producing pyrocumulus were obtained. These observations suggested that the National Lightning Detection Network (NLDN) was not sensitive enough to detect the small IC flashes that appear to be the dominant mode of lightning in these clouds. However, after an upgrade to the network in late 2012, the NLDN began detecting some of this pyrocumulus lightning. Multiple pyrocumulus clouds documented by the University of Wisconsin for various fires in 2013 and 2014 (including over the Rim, West Fork Complex, Yarnell Hill, Hardluck, and several other incidents) are examined and reported on here. This study exploits the increased-sensitivity NLDN as well as the new nationwide U.S. network of polarimetric Next-generation Radars (NEXRADs). These observations document the common occurrence of a polarimetric "dirty ice" signature - modest reflectivities (20-40+ dBZ), near-zero differential reflectivity, and reduced correlation coefficient (less than 0.9) - prior to the production of lightning. This signature is indicative of a mixture of ash and ice particles in the upper levels of the pyro-cloud (less than -20 C), with the ice interpreted as being necessary for pyro-cloud electrification. Pseudo-Geostationary Lightning Mapper (GLM) data will be produced from the 2012 LMA observations, and the ability of GLM to detect small pyrocumulus ICs will be assessed. The utility of lightning and polarimetric radar for documenting rapid wildfire growth, as well as for documenting pyrocumulus impacts on the composition of the upper troposphere

  19. The Effects of Ice on the Frictional Electrification of Plumes

    NASA Astrophysics Data System (ADS)

    Méndez Harper, J.; Courtland, L. M.; Dufek, J.

    2015-12-01

    Studies of the Redoubt (2009), Eyjafjallajökull (2010), and the Cordón Caulle (2011) eruptions and associated electrical activity suggest that ice is a catalyst for the generation of plume lightning [Behnke et al., 2012; Arason et al., 2011; Nicora et al., 2013]. Indeed, the number lightning flashes in the umbrella and convective regions of the plume seems to correlate with lower, ice-forming temperatures. As in conventional thunderstorms, electric charge accumulation and separation in cold plumes may arise from the interplay between ice grains and graupel. However, charging may also be driven by triboelectrification (frictional charging), resulting from collisions between ice and ash grains. Decades of research have shown that fluidized granular materials comprising species of distinct composition often produce more efficient electrification than the interaction of chemically identical particles under similar hydrodynamic regime [e.g. Forward et al., 2009]. Thus, tribocharging in a combined ice and silicate granular flow is likely to yield grains with higher charges than those encountered in a flow composed solely of silicate grains, facilitating the generation of lightning [Méndez Harper and Dufek, 2015, submitted]. To indagate this hypothesis, we have developed a novel methodology to measure the time-dependent charging of individual micron-sized particles in both dry, silicate flows and silicate plus ice flows. Pure ash runs are conducted in a dry (<1 % humidity) environment with a temperature variation of -40o to 25o C. Runs involving ice are performed between -40o and 2o C, permitting us to quantify charging in the mixture as water transmogrifies from solid ice to a more mush-like substance. Additionally, we report on how collisional energy and rates influence electrification in these granular materials. We show that, although the variations in ash composition (basalt to rhyolite) tend to be of little consequence for charging, the presence of a water phase

  20. Simulating storm electrification with bin and bulk microphysics

    NASA Astrophysics Data System (ADS)

    Mansell, E. R.

    2013-12-01

    Simulated storm electrification can be highly dependent on the parameterizations of microphysical processes, particularly those involving ice particles. Commonly-used bulk microphysics assume a functional form of the particle size distribution and predict one or more moments of the distribution, such as total mass, number concentration, and reflectivity. Bin schemes, on the other hand, allow the particle spectrum to evolve by predicting the number of particles in discrete size ranges (bins). Bin schemes are often promoted as benchmark solutions, but have much greater computational expense and can have other disadvantages. Only a few studies have compared results for bin and bulk schemes within the same model framework, which controls for differences in model numerics and other physics. Here, the bin microphysics scheme of Takahashi has been incorporated into the COMMAS model for comparison with the 2-3-moment bulk scheme. The resulting electrification, charge structure and lightning are compared, as well. Charge separation and transfer have been newly added to the bin scheme, along with some updates to the physics, such as improved ice melting. Thus the same laboratory-based charging schemes from previous work can be used with both microphysics packages. The bulk and bin schemes generally have similar microphysical features in the simulations. Differences can result in part from differences the parameterizations of partical interactions (and particle types) as much as from the simple difference in size distributions. For example both the bin and bulk schemes are sensitive to the concentration of cloud condensation nuclei, as shown in recent work from the bulk scheme. Results will be presented for idealized 2-dimensional cases and for fully 3D simulations of a small multicell thunderstorms.

  1. MicroRNA-378 regulates oocyte maturation via the suppression of aromatase in porcine cumulus cells.

    PubMed

    Pan, Bo; Toms, Derek; Shen, Wei; Li, Julang

    2015-03-15

    We sought to investigate whether miR-378 plays a role in cumulus cells and whether the manipulation of miRNA levels in cumulus cells influences oocyte maturation in vitro. Cumulus-oocyte complexes (COCs) from ovarian follicles had significantly lower levels of precursor and mature miR-378 in cumulus cells surrounding metaphase II (MII) oocytes than cumulus cells surrounding germinal vesicle (GV) oocytes, suggesting a possible role of miR-378 during COC maturation. Overexpression of miR-378 in cumulus cells impaired expansion and decreased expression of genes associated with expansion (HAS2, PTGS2) and oocyte maturation (CX43, ADAMTS1, PGR). Cumulus cell expression of miR-378 also suppressed oocyte progression from the GV to MII stage (from 54 ± 2.7 to 31 ± 5.1%), accompanied by a decrease of growth differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15), zona pellucida 3 (ZP3), and CX37 in the oocytes. Subsequent in vitro fertilization resulted in fewer oocytes from COCs overexpressing miR-378 reaching the blastocyst stage (7.3 ± 0.7 vs. 16.6 ± 0.5%). miR-378 knockdown led to increased cumulus expansion and oocyte progression to MII, confirming a specific effect of miR-378 in suppressing COC maturation. Aromatase (CYP19A1) expression in cumulus cells was also inhibited by miR-378, leading to a significant decrease in estradiol production. The addition of estradiol to IVM culture medium reversed the effect of miR-378 on cumulus expansion and oocyte meiotic progression, suggesting that decreased estradiol production via suppression of aromatase may be one of the mechanisms by which miR-378 regulates the maturation of COCs. Our data suggest that miR-378 alters gene expression and function in cumulus cells and influences oocyte maturation, possibly via oocyte-cumulus interaction and paracrine regulation.

  2. Method for collecting and immobilizing individual cumulus cells enabling quantitative immunofluorescence analysis of proteins.

    PubMed

    Appeltant, R; Maes, D; Van Soom, A

    2015-07-01

    Most immunofluorescence methods rely on techniques dealing with a very large number of cells. However, when the number of cells in a sample is low (e.g., when cumulus cells must be analyzed from individual cumulus-oocyte complexes), specific techniques are required to conserve, fix, and analyze cells individually. We established and validated a simple and effective method for collecting and immobilizing low numbers of cumulus cells that enables easy and quick quantitative immunofluorescence analysis of proteins from individual cells. To illustrate this technique, we stained proprotein of a disintegrin and metalloproteinase with thrombospondin-like repeats-1 (proADAMTS-1) and analyzed its levels in individual porcine cumulus cells.

  3. Selective binding of human cumulus cell-secreted glycoproteins to human spermatozoa during capacitation in vitro

    SciTech Connect

    Tesarik, J.; Kopecny, V.; Dvorak, M.

    1984-06-01

    The results of this study demonstrate that glycoproteins manufactured by human cumulus cells can be detected bound to human spermatozoa incubated in capacitational medium containing the labeled cumulus-cell secretions. Cumulus-cell-secreted glycoproteins were labeled with a mixture of /sup 3/H-methionine and /sup 3/H-tryptophan or with 3H-fucose, and the binding of the labeled compounds to spermatozoa was evaluated by autoradiography. The binding was highly selective, involving only approximately 1% of the samples of spermatozoa used. The results suggest that the binding of cumulus-cell-secreted glycoproteins to spermatozoa may represent a final and highly selective step in human sperm capacitation.

  4. Changes in streamflow and summary of major-ion chemistry and loads in the North Fork Red River basin upstream from Lake Altus, northwestern Texas and western Oklahoma, 1945-1999

    USGS Publications Warehouse

    Smith, S. Jerrod; Wahl, Kenneth L.

    2003-01-01

    Upstream from Lake Altus, the North Fork Red River drains an area of 2,515 square miles. The quantity and quality of surface water are major concerns at Lake Altus, and water-resource managers and consumers need historical information to make informed decisions about future development. The Lugert-Altus Irrigation District relies on withdrawals from the lake to sustain nearly 46,000 acres of agricultural land. Kendall's tau tests of precipitation data indicated no statistically significant trend over the entire 100 years of available record. However, a significant increase in precipitation occurred in the last 51 years. Four streamflow-gaging stations with more than 10 years of record were maintained in the basin. These stations recorded no significant trends in annual streamflow volume. Two stations, however, had significant increasing trends in the base-flow index, and three had significant decreasing trends in annual peak flows. Major-ion chemistry in the North Fork Red River is closely related to the chemical composition of the underlying bedrock. Two main lithologies are represented in the basin upstream from Lake Altus. In the upper reaches, young and poorly consolidated sediments include a range of sizes from coarse gravel to silt and clay. Nearsurface horizons commonly are cemented as calcium carbonate caliche. Finer-grained gypsiferous sandstones and shales dominate the lower reaches of the basin. A distinct increase in dissolved solids, specifically sodium, chloride, calcium, and sulfate, occurs as the river flows over rocks that contain substantial quantities of gypsum, anhydrite, and dolomite. These natural salts are the major dissolved constituents in the North Fork Red River.

  5. A numerical study of thunderstorm electrification: Model development and case study

    SciTech Connect

    Norville, K.; Baker, M. ); Latham, J. )

    1991-04-20

    The authors have developed a numerical model for examining the thunderstorm electrification process in which they assume the electrification is entirely due to noinductive charge transfer between colliding ice crystals and hail. Since this ice-hail charge mechanism is very independent on particle sizes and distributions, they use an explicit microphysical framework. To maintain simplicity, the electrification model is kinematic; thus the temperature and velocity fields are input into the electrification model. These fields can be either calculated by a background model or retrieved from observations. For this study, they have used the cloud model of Taylor (1989) to generate the temperature and velocity fields to examine the July 19, 1981, CCOPE thundercloud. Using these fields, the electrification model produced time-dependent ice particle concentrations, radar reflectives, charge and vertical electric field distributions in good general agreement with those observed. The model produced a maximum electric field strength of 1.27 kV/cm, which is on the order of that needed for lightning initiation, and this maximum occured very close to the time of the observed discharge (as inferred by the sailplane measurements). Thus the ice-hail charge mechanism appears to have played an important role in the electrical development of the July 19 cloud. The details of the electrification depended on the liquid water content and the glaciation processes, and particularly on the ice crystal characteristics. Rapid growth of the crystals to riming sizes (>400{mu}) yielded the most efficient charging. The electrification was also sensitive to the ice-ice sticking efficiency but not to the characteristics of the large riming ice.

  6. Shallow Cumulus Variability at the ARM Eastern North Atlantic Site

    NASA Astrophysics Data System (ADS)

    Lamer, K.; Kollias, P.; Ghate, V. P.; Luke, E. P.

    2016-12-01

    Cumulus clouds play a critical role in modulating the radiative and hydrological budget of the lower troposphere. These clouds, which are ubiquitous in regions of large-scale subsidence over the oceans, tend to be misrepresented in global climate models. Island-based, long-term, high-resolution ground-based observations can provide valuable insights on the factors controlling their macroscopic and microphysical properties and subsequenlty assist in model evaluation and guidance. Previous studies, limited to fair-weather cumuli over land, revealed that their fractional coverage is only weakly correlated with several parameters; the best ones being complex dynamical characteristics of the subcloud layer (vertical velocity skewness and eddy coherence). Other studies noted a relationship between cumuli depth and their propensity to precipitate. The current study will expand on such analysis by performing detail characterization of the full spectrum of shallow cumulus fields from non-precipitating to precipitating in the context of the large-scale forcing (i.e. thermodynamic structure and subsidence rates). Two years of ground-based remote sensing observations collected at the Atmospheric Radiation Measurement (ARM) Eastern North Atlantic (ENA) site are used to document macroscopic (cloud depth, cord length, cover), microphysical (liquid water path, cloud base rain rate) and dynamical (cloud base mass flux, eddy dissipation rate) cumuli properties. The observed variability in shallow cumulus is examined in relation to the variability of the large-scale environment as captured by the humidity profile, the magnitude of the low-level horizontal winds and near-surface aerosol conditions.

  7. A New Framework for Cumulus Parametrization - A CPT in action

    NASA Astrophysics Data System (ADS)

    Jakob, C.; Peters, K.; Protat, A.; Kumar, V.

    2016-12-01

    The representation of convection in climate model remains a major Achilles Heel in our pursuit of better predictions of global and regional climate. The basic principle underpinning the parametrisation of tropical convection in global weather and climate models is that there exist discernible interactions between the resolved model scale and the parametrised cumulus scale. Furthermore, there must be at least some predictive power in the larger scales for the statistical behaviour on small scales for us to be able to formally close the parametrised equations. The presentation will discuss a new framework for cumulus parametrisation based on the idea of separating the prediction of cloud area from that of velocity. This idea is put into practice by combining an existing multi-scale stochastic cloud model with observations to arrive at the prediction of the area fraction for deep precipitating convection. Using mid-tropospheric humidity and vertical motion as predictors, the model is shown to reproduce the observed behaviour of both mean and variability of deep convective area fraction well. The framework allows for the inclusion of convective organisation and can - in principle - be made resolution-aware or resolution-independent. When combined with simple assumptions about cloud-base vertical motion the model can be used as a closure assumption in any existing cumulus parametrisation. Results of applying this idea in the the ECHAM model indicate significant improvements in the simulation of tropical variability, including but not limited to the MJO. This presentation will highlight how the close collaboration of the observational, theoretical and model development community in the spirit of the climate process teams can lead to significant progress in long-standing issues in climate modelling while preserving the freedom of individual groups in pursuing their specific implementation of an agreed framework.

  8. Sensitivity of land surface and Cumulus schemes for Thunderstorm prediction

    NASA Astrophysics Data System (ADS)

    Kumar, Dinesh; Mohanty, U. C.; Kumar, Krishan

    2016-06-01

    The cloud processes play an important role in all forms of precipitation. Its proper representation is one of the challenging tasks in mesoscale numerical simulation. Studies have revealed that mesoscale feature require proper initialization which may likely to improve the convective system rainfall forecasts. Understanding the precipitation process, model initial condition accuracy and resolved/sub grid-scale precipitation processes representation, are the important areas which needed to improve in order to represent the mesoscale features properly. Various attempts have been done in order to improve the model performance through grid resolution, physical parameterizations, etc. But it is the physical parameterizations which provide a convective atmosphere for the development and intensification of convective events. Further, physical parameterizations consist of cumulus convection, surface fluxes of heat, moisture, momentum, and vertical mixing in the planetary boundary layer (PBL). How PBL and Cumulus schemes capture the evolution of thunderstorm have been analysed by taking thunderstorm cases occurred over Kolkata, India in the year 2011. PBL and cumulus schemes were customized for WSM-6 microphysics because WSM series has been widely used in operational forecast. Results have shown that KF (PBL scheme) and WSM-6 (Cumulus Scheme) have reproduced the evolution of surface variable such as CAPE, temperature and rainfall very much like observation. Further, KF and WSM-6 scheme also provided the increased moisture availability in the lower atmosphere which was taken to higher level by strong vertical velocities providing a platform to initiate a thunderstorm much better. Overestimation of rain in WSM-6 occurs primarily because of occurrence of melting and freezing process within a deeper layer in WSM-6 scheme. These Schemes have reproduced the spatial pattern and peak rainfall coverage closer to TRMM observation. It is the the combination of WSM-6, and KF schemes

  9. An Empirical Cumulus Parameterization Scheme for a Global Spectral Model

    NASA Technical Reports Server (NTRS)

    Rajendran, K.; Krishnamurti, T. N.; Misra, V.; Tao, W.-K.

    2004-01-01

    Realistic vertical heating and drying profiles in a cumulus scheme is important for obtaining accurate weather forecasts. A new empirical cumulus parameterization scheme based on a procedure to improve the vertical distribution of heating and moistening over the tropics is developed. The empirical cumulus parameterization scheme (ECPS) utilizes profiles of Tropical Rainfall Measuring Mission (TRMM) based heating and moistening derived from the European Centre for Medium- Range Weather Forecasts (ECMWF) analysis. A dimension reduction technique through rotated principal component analysis (RPCA) is performed on the vertical profiles of heating (Q1) and drying (Q2) over the convective regions of the tropics, to obtain the dominant modes of variability. Analysis suggests that most of the variance associated with the observed profiles can be explained by retaining the first three modes. The ECPS then applies a statistical approach in which Q1 and Q2 are expressed as a linear combination of the first three dominant principal components which distinctly explain variance in the troposphere as a function of the prevalent large-scale dynamics. The principal component (PC) score which quantifies the contribution of each PC to the corresponding loading profile is estimated through a multiple screening regression method which yields the PC score as a function of the large-scale variables. The profiles of Q1 and Q2 thus obtained are found to match well with the observed profiles. The impact of the ECPS is investigated in a series of short range (1-3 day) prediction experiments using the Florida State University global spectral model (FSUGSM, T126L14). Comparisons between short range ECPS forecasts and those with the modified Kuo scheme show a very marked improvement in the skill in ECPS forecasts. This improvement in the forecast skill with ECPS emphasizes the importance of incorporating realistic vertical distributions of heating and drying in the model cumulus scheme. This

  10. The Severe Thunderstorm Electrification and Precipitation Study (STEPS)

    NASA Astrophysics Data System (ADS)

    Rutledge, S. A.; Lang, T. J.

    2003-12-01

    During May-July 2000, the Severe Thunderstorm Electrification and Precipitation Study (STEPS) was conducted in the High Plains, near the Colorado-Kansas border, in order to achieve a better understanding of the interactions between kinematics, precipitation, and electrification in severe thunderstorms. Specific scientific objectives included: 1) understanding the apparent major differences in precipitation output from supercells that have led to them being classified as low-precipitation (LP), classic or medium-precipitation, and high-precipitation; 2) understanding lightning formation and behavior in storms, and how lightning differs among storm types, particularly to better understand the mechanisms by which storms produce predominantly positive cloud-to-ground (CG) lightning; and 3) to verify and improve microphysical interpretations from polarimetric radar. The project involved the use of a multiple-Doppler and polarimetric radar network, as well as a time-of-arrival VHF lightning mapping system, the T-28 armored research aircraft, electric field meters carried on balloons, mobile mesonet vehicles, instruments to detect and classify transient luminous events over thunderstorms (TLEs; e.g., sprites and blue jets), and mobile atmospheric sounding equipment. The project was a major success, gathering unprecedented data on a wealth of diverse cases, including LP storms, supercells, and mesoscale convective systems, among others. Many of the storms produced mostly positive CG lightning during their lifetimes, and also exhibited unusual electrical structures such as a possibly inverted dipole. The 29 June supercell case has received considerable study to date including the analysis of polarimetric radar data to demonstrate couplings between storm dynamics and the formation of hail and graupel, which lead to formation of significant positive charge in the mid-levels and copious amounts of positive cloud-to-ground lightning. The charge structure in the 29 June case

  11. A cumulus parameterization including mass fluxes, vertical momentum dynamics, and mesoscale effects

    SciTech Connect

    Donner, L.J. )

    1993-03-15

    A formulation for parameterizing cumulus convection, which treats cumulus vertical momentum dynamics and mass fluxes consistently, is presented. This approach predicts the penetrative extent of cumulus updrafts on the basis of their vertical momentum and provides a basis for treating cumulus microphysics using formulations that depend on vertical velocity. Treatments for cumulus microphysics are essential if the water budgets of convective systems are to be evaluated for treating mesoscale stratiform processes associated with convection, which are important for radiative interactions influencing climate. The water budget of the cumulus updrafts is used to drive a semi-empirical parameterization for the large-scale effects of the mesoscale circulations associated with deep convection. The parameterization was applied to two tropical thermodynamic profiles whose diagnosed forcing by convective systems differed significantly. The deepest of the updrafts penetrated the upper troposphere, while the shallower updrafts penetrated into the region of the mesoscale anvil. The relative numbers of cumulus updrafts of characteristic vertical velocities comprising the parameterized ensemble corresponded well with available observations. The large-scale heating produced by the ensemble without mesoscale circulations was concentrated at lower heights than observed or was characterized by excessive peak magnitudes. An unobserved large-scale source of water vapor was produced in the middle troposphere. When the parameterization for mesoscale effects was added, the large-scale thermal and moisture forcing predicted by the parameterization agreed well with observations for both cases. The significance of mesoscale processes suggests that future cumulus parameterization development will need to treat some radiative processes.

  12. Interaction of a cumulus cloud ensemble with the large-scale environment. III - Semi-prognostic test of the Arakawa-Schubert cumulus parameterization

    NASA Technical Reports Server (NTRS)

    Lord, S. J.

    1982-01-01

    The verification of the Arakawa and Schubert (1974) cumulus parameterization is continued using a semiprognostic approach. Observed data from Phase III of GATE are used to provide estimates of the large-scale forcing of a cumulus ensemble at each observation time. Instantaneous values of the precipitation and the warming and drying due to cumulus convection are calculated using the parameterization. The results show that the calculated precipitation agrees very well with estimates from the observed large-scale moisture budget and from radar observations. The calculated vertical profiles of cumulus warming and drying also are quite similar to the observed. It is shown that the closure assumption adopted in the parameterization (the cloud-work function quasi-equilibrium) results in errors of generally less than 10% in the calculated precipitation. The sensitivity of the parameterization to some assumptions of the cloud ensemble model and the solution method for the cloud-base mass flux is investigated.

  13. Mouse cumulus-denuded oocytes restore developmental capacity completely when matured with optimal supplementation of cysteamine, cystine, and cumulus cells.

    PubMed

    Zhou, Ping; Wu, Yan-Guang; Wei, De-Li; Li, Qing; Wang, Gang; Zhang, Jie; Luo, Ming-Jiu; Tan, Jing-He

    2010-04-01

    Our objectives were to study how cysteamine, cystine, and cumulus cells (CCs), as well as oocytes interact to increase oocyte intracellular glutathione (GSH) and thereby to establish an efficient in vitro maturation system for cumulus-denuded oocytes (DOs). Using M16 that contained no thiol as maturation medium, we showed that when supplemented alone, neither cystine nor cysteamine promoted GSH synthesis of mouse DOs, but they did when used together. Although goat CCs required either cysteamine or cystine to promote GSH synthesis, mouse CCs required both. In the presence of cystine, goat CCs produced cysteine but mouse CCs did not. Cysteamine reduced cystine to cysteine in cell-free M16. When TCM-199 that contained 83 microM cystine was used as maturation medium, supplementation with cysteamine alone had no effect, but supplementation with 100 microM cysteamine and 200 microM cystine increased blastulation of DOs matured with CC coculture to a level as high as achieved in cumulus-surrounded oocytes (COCs). Similar numbers of young were produced after two-cell embryos from mouse COCs or CC-cocultured DOs matured with optimal thiol supplementation were transferred to pseudopregnant recipients. It is concluded that 1) mouse CCs can use neither cysteamine nor cystine to promote GSH synthesis, but goat CCs can use either one; 2) goat CCs promote mouse oocyte GSH synthesis by reducing cystine to cysteine, but how they use cysteamine requires further investigation; and 3) mouse DOs can use neither cystine nor cysteamine for GSH synthesis, but they restore developmental capacity completely when matured in the presence of optimum supplementation of cysteamine, cystine, and CCs.

  14. Protein profiling the differences between diabetic and normal mouse cumulus cells.

    PubMed

    Jiang, Guang-Jian; Ma, Jun-Yu; Zhang, Guang-Li; Mo, Fang-Fang; Zhang, Dong-Wei; Gao, Si-Hua; Li, Xiu-Li

    2014-12-01

    As the number of young people suffering from diabetes increases worldwide, the impact of this disease on human reproduction urgently needs to be addressed. Here we compared the proteomes of cumulus cells of super-ovulated cumulus-oocyte complexes from diabetic and normal mice. We identified 57 up-regulated and 74 down-regulated proteins in diabetic cumulus cells; among these groups were proteins associated with cell cycle, cellular communication, epigenetic regulation, protein localization, and chromatin organization - all in accordance with type I diabetes. The poor-quality follicles derived from diabetic mice were further enforced by the presence of glycoproteins that are specifically expressed by the oocyte or oviductal epithelial cells in the cumulus-cell samples. In conclusion, the proteomic differences between diabetic and normal cumulus cells provide targets for improving the reproduction health of type I diabetic patients.

  15. Interaction of a cumulus cloud ensemble with the large-scale environment. I

    NASA Technical Reports Server (NTRS)

    Arakawa, A.; Schuber, W. H.

    1974-01-01

    A theory of the interaction of a cumulus cloud ensemble with the large-scale environment is developed. In this theory, the large-scale environment is divided into the subcloud mixed layer and the region above. The time changes of the environment are governed by the heat and moisture budget equations for the subcloud mixed layer and for the region above, and by a prognostic equation for the depth of the mixed layer. In the environment above the mixed layer, the cumulus convection affects the temperature and moisture fields through cumulus-induced subsidence and detrainment of saturated air containing liquid water which evaporates in the environment. In the subcloud mixed layer, the cumulus convection does not act directly on the temperature and moisture fields, but it affects the depth of the mixed layer through cumulus-induced subsidence.

  16. General features of certain RNA populations from gametes and cumulus cells.

    PubMed

    Payton, Rebecca R; Rispoli, Louisa A; Edwards, J Lannett

    2010-12-01

    Results described herein provide insight regarding certain features of gamete RNA and how they compare to cumulus cell RNA. In particular, 28S/18S rRNA ratio and size distribution of RNA molecules differed in total RNA from oocytes versus surrounding cumulus cells. Specifically, oocyte total RNA had a lower rRNA ratio and an increased abundance of smaller RNA sizes compared to RNA from surrounding cumulus. Extensive efforts demonstrated that observed differences were repeatable whether oocyte maturation occurred in vitro or in vivo, and were similar between the nuclear stages examined. Features of oocyte RNA were conserved across six mammalian species, yet differed from surrounding cumulus. Profiles of sperm RNA were also examined but had no discernible ribosomal RNA peaks and were conserved across four mammalian species. Because the oocyte and spermatozoon are highly specialized cells representing unique molecular entities required for proper embryo development, dissimilarities described herein likely represent real gamete versus cumulus RNA differences.

  17. Hampered cumulus expansion of porcine cumulus-oocyte complexes by excessive presence of alpha2 -macroglobulin is likely mediated via inhibition of zinc-dependent metalloproteases.

    PubMed

    Appeltant, Ruth; Beek, Josine; Maes, Dominiek; Bijttebier, Jo; Van Steendam, Katleen; Nauwynck, Hans; Van Soom, Ann

    2017-09-01

    In vitro maturation (IVM) in serum causes hampered expansion of porcine cumulus-oocyte complexes (COCs) due to excessive alpha2 -macroglobulin (A2M). This study investigated two hypotheses that could explain the effect of A2M: (i) binding of epidermal growth factor (EGF) to A2M, followed by its decreased availability; and (ii) inhibition of zinc-dependent metalloproteases. Cumulus expansion was evaluated based on the diameter of the COCs, the proportion of COCs participating in a floating cloud and the proportion of COCs with loss of cumulus cells. The first hypothesis of decreased EGF availability was tested by increasing the EGF concentration (20 and 50 ng/mL vs. 10 ng/mL), but was not confirmed because cumulus expansion did not improve. To verify the second hypothesis of inhibited zinc-dependent metalloproteases, the effect of tissue inhibitor of metalloproteases-3 (TIMP-3) on cumulus expansion during IVM with and without A2M was investigated. To immuno-neutralize A2M, serum was pre-incubated with A2M antibodies. Impaired cumulus expansion because of TIMP-3 could only be observed during IVM in 10% of serum with A2M antibodies. No effect of TIMP-3 was observed in medium without A2M antibodies. These results indicate that A2M and TIMP-3 share a common target, a zinc-dependent metalloprotease. Future research is directed toward the identification of the protease involved. © 2017 Japanese Society of Animal Science.

  18. (Monitoring and evaluation of the Central American Rural Electrification Program)

    SciTech Connect

    Garcia, A. III )

    1990-03-20

    CARES has been successful in leveraging its effort with similar programs in other countries. NRECA has done an exceptional job of coordinating the related activities of other AID contracts. The informal lines of communication appear to work well with a relaxed and productive environment evident. ROCAP has expressed confidence in the ability of NRECA to carry out the Workplan successfully. Recent initiatives by Mr. Funes in the area of indicators are seen by the review team as a positive and mutual step to articulate specific goals and accomplishments. Communication and coordination among the ROCAP staff and the local AID Mission appears to have improved since last mentioned in the Engineering Standards Review. This is especially true in Guatemala and Costa Rica. Better reporting procedures would facilitate NRECA-ROCAP-AID Mission communication. Impressive progress has been made in the way local officials approach rural electrification. This is very evident in the areas of engineering design and the productive uses campaign. The Planning and Engineering sections of INDE and CEL rapidly adopted the new mechanical strength based standards as reasonable design solutions. Similarly, productive uses has received much greater attention by all of the various divisions of the utilities in El Salvador, Guatemala and Costa Rica. This was not the case previous to the CARES Project. The final report specifically addresses several areas that should be de-emphasized or given more attention. 26 refs.

  19. Philippines: rural electrification. Project impact evaluation report No. 15

    SciTech Connect

    Mandel, D.H.; Allgeier, P.F.; Wasserman, G.; Hickey, G.; Salazar, R.

    1980-12-01

    AID's overall evaluation of its Philippine Rural Electrification (RE) program, consisting of eight successive projects, had limited effect on the rural poor and the economic development process. This program began in 1965 and has since energized 844 (59% of the national total) Philippine municipalities, 9088 (27%) barrios, 1,159,434 (20%) households, and 101 new cooperatives; resulting in a change of schedule for total national energization from 1980 to 1987. To improve the productive capacity of the poor, cooperatives were organized and lent funds to extend electrical power into their areas. Many of the poor, however, could not afford its installation, continued use, or more than one or two light bulbs a month. Community lighting, such as street-lighting, indirectly helped the poor in various ways, such as by providing greater personal security. Those with sufficient financial resources or skills were able to use the electricity for entrepreneurial activities. RE impact upon development occurred in areas with a concentrated population, available technical skills and capital, and access to large and diverse markets. Active promotion of electricity-dependent investments and projects also increased program impact.

  20. Radial-arrayed rotary electrification for high performance triboelectric generator.

    PubMed

    Zhu, Guang; Chen, Jun; Zhang, Tiejun; Jing, Qingshen; Wang, Zhong Lin

    2014-03-04

    Harvesting mechanical energy is an important route in obtaining cost-effective, clean and sustainable electric energy. Here we report a two-dimensional planar-structured triboelectric generator on the basis of contact electrification. The radial arrays of micro-sized sectors on the contact surfaces enable a high output power of 1.5 W (area power density of 19 mW cm(-2)) at an efficiency of 24%. The triboelectric generator can effectively harness various ambient motions, including light wind, tap water flow and normal body movement. Through a power management circuit, a triboelectric-generator-based power-supplying system can provide a constant direct-current source for sustainably driving and charging commercial electronics, immediately demonstrating the feasibility of the triboelectric generator as a practical power source. Given exceptional power density, extremely low cost and unique applicability resulting from distinctive mechanism and structure, the triboelectric generator can be applied not only to self-powered electronics but also possibly to power generation at a large scale.

  1. Role of contact electrification and electrostatic interactions in gecko adhesion.

    PubMed

    Izadi, Hadi; Stewart, Katherine M E; Penlidis, Alexander

    2014-09-06

    Geckos, which are capable of walking on walls and hanging from ceilings with the help of micro-/nano-scale hierarchical fibrils (setae) on their toe pads, have become the main prototype in the design and fabrication of fibrillar dry adhesives. As the unique fibrillar feature of the toe pads of geckos allows them to develop an intimate contact with the substrate the animal is walking on or clinging to, it is expected that the toe setae exchange significant numbers of electric charges with the contacted substrate via the contact electrification (CE) phenomenon. Even so, the possibility of the occurrence of CE and the contribution of the resulting electrostatic interactions to the dry adhesion of geckos have been overlooked for several decades. In this study, by measuring the magnitude of the electric charges, together with the adhesion forces, that gecko foot pads develop in contact with different materials, we have clarified for the first time that CE does contribute effectively to gecko adhesion. More importantly, we have demonstrated that it is the CE-driven electrostatic interactions which dictate the strength of gecko adhesion, and not the van der Waals or capillary forces which are conventionally considered as the main source of gecko adhesion.

  2. Electrification ratio and renewable energy in Papua Province

    NASA Astrophysics Data System (ADS)

    Innah, Herbert; Kariongan, Jackobus; Liga, Marthen

    2017-03-01

    Indonesia government through the Ministry of Energy and Mineral Resources, in the beginning of year 2016, introduced a program named "Indonesia Terang" or Bright Indonesia. The aimed of this program is to speed up Electrification Rate (ER) with priority to the six provinces at Eastern area of Indonesia including Papua Province. The target of Indonesian's ER by 2019 is 97%. While the Indonesian's national ER already high (88.30%) in 2015, Papua still the lowest ER (45.93%) among the provinces. The scenario to boost up ER in the Eastern area by connected the consumers at villages which not electrified yet to the new Renewable Energy sources. This paper presents an overview of current situation of Electricity Infrastructure and Operation particularly on the mountain area which has high populated compare to coastal area but the average RE below 10%. Case studies of electricity infrastructure profile from mountain area were conducted to identify and reveal the challenge to achieve the Bright Indonesia objectives. Also, the assessment of the visibility according to the high target from this program will be presented.

  3. Electricity distribution industry restructuring, electrification, and competition in South Africa

    SciTech Connect

    Galen, P S

    1997-07-01

    This paper reviews the status of the South African electricity supply industry (ESI) and proposals for reorienting and restructuring it. South Africa has been intensely examining its ESI for more than 4 years in an effort to determine whether and how it should be restructured to best support the country`s new economic development and social upliftment goals. The debate has been spirited and inclusive of most ESI stakeholders. The demands on and expectations for the ESI are many and varied. The debate has reflected this diversity of interests and views. In essence, however, there is a consensus on what is expected of the industry, namely, to extend provision of adequate, reliable, and affordable electricity service to all citizens and segments of the economy. This means a large-scale electrification program to reach as many of the nearly 50% of households currently without electricity service as soon as possible, tariff reform to promote equity and efficiency, and the upgrading of service quality now being provided by some of the newly consolidated municipal authorities. The issues involved are how best to achieve these results within the context of the national Reconstruction and Development Program, while accounting for time and resource constraints and balancing the interests of the various parties.

  4. Linear-grating triboelectric generator based on sliding electrification.

    PubMed

    Zhu, Guang; Chen, Jun; Liu, Ying; Bai, Peng; Zhou, Yu Sheng; Jing, Qingshen; Pan, Caofeng; Wang, Zhong Lin

    2013-05-08

    The triboelectric effect is known for many centuries and it is the cause of many charging phenomena. However, it has not been utilized for energy harvesting until very recently. (1-5) Here we developed a new principle of triboelectric generator (TEG) based on a fully contacted, sliding electrification process, which lays a fundamentally new mechanism for designing universal, high-performance TEGs to harvest diverse forms of mechanical energy in our daily life. Relative displacement between two sliding surfaces of opposite triboelectric polarities generates uncompensated surface triboelectric charges; the corresponding polarization created a voltage drop that results in a flow of induced electrons between electrodes. Grating of linear rows on the sliding surfaces enables substantial enhancements of total charges, output current, and current frequency. The TEG was demonstrated to be an efficient power source for simultaneously driving a number of small electronics. The principle established in this work can be applied to TEGs of different configurations that accommodate the needs of harvesting energy and/or sensing from diverse mechanical motions, such as contacted sliding, lateral translation, and rotation/rolling.

  5. Radial-arrayed rotary electrification for high performance triboelectric generator

    NASA Astrophysics Data System (ADS)

    Zhu, Guang; Chen, Jun; Zhang, Tiejun; Jing, Qingshen; Wang, Zhong Lin

    2014-03-01

    Harvesting mechanical energy is an important route in obtaining cost-effective, clean and sustainable electric energy. Here we report a two-dimensional planar-structured triboelectric generator on the basis of contact electrification. The radial arrays of micro-sized sectors on the contact surfaces enable a high output power of 1.5 W (area power density of 19 mW cm-2) at an efficiency of 24%. The triboelectric generator can effectively harness various ambient motions, including light wind, tap water flow and normal body movement. Through a power management circuit, a triboelectric-generator-based power-supplying system can provide a constant direct-current source for sustainably driving and charging commercial electronics, immediately demonstrating the feasibility of the triboelectric generator as a practical power source. Given exceptional power density, extremely low cost and unique applicability resulting from distinctive mechanism and structure, the triboelectric generator can be applied not only to self-powered electronics but also possibly to power generation at a large scale.

  6. Pyro-electrification of polymer membranes for cell patterning

    NASA Astrophysics Data System (ADS)

    Rega, R.; Gennari, O.; Mecozzia, L.; Grilli, S.; Pagliarulo, V.; Ferraro, P.

    2016-05-01

    In the recent years, much attention has been devoted to the possibility of charging polymer-based materials, due to their potential in developing large-scale and inexpensive flexible thin-film technology. The availability of localized electrostatic fields is in of great interest for a huge amount of applications such as distribution of biomolecules and cells from the liquid phase. Here we report a voltage-free pyro-electrification (PE) process able to induce permanent dipoles into polymer layers; the lithium niobate (LN) crystal is the key component that plays the multi-purpose role of sustaining, heating and poling the polymer layer that is then peeled-off easily in order to have a free-standing charged membrane. The results show the fascinating application for the living cell patterning. It well known that cell behaviour is affected by chemical and topographical cues of substrate. In fact, polymers, such as polystyrene (PS) and poly(methyl methacrylate) (PMMA), are naturally cytophobic and require specific functionalization treatments in order to promote cell adhesion. Through our proposal technique, it's possible to obtain spontaneous organization and a driven growth of SH-SY5Y cells that is solely dictated by the nature of the charge polymer surface, opening, in this way, the innovative chance to manipulate and transfer biological samples on a free-standing polymer layer [1].

  7. Pyro-electrification of polymer membranes for cell patterning

    SciTech Connect

    Rega, R.; Gennari, O.; Mecozzia, L.; Grilli, S.; Pagliarulo, V.; Ferraro, P.

    2016-05-18

    In the recent years, much attention has been devoted to the possibility of charging polymer-based materials, due to their potential in developing large-scale and inexpensive flexible thin-film technology. The availability of localized electrostatic fields is in of great interest for a huge amount of applications such as distribution of biomolecules and cells from the liquid phase. Here we report a voltage-free pyro-electrification (PE) process able to induce permanent dipoles into polymer layers; the lithium niobate (LN) crystal is the key component that plays the multi-purpose role of sustaining, heating and poling the polymer layer that is then peeled-off easily in order to have a free-standing charged membrane. The results show the fascinating application for the living cell patterning. It well known that cell behaviour is affected by chemical and topographical cues of substrate. In fact, polymers, such as polystyrene (PS) and poly(methyl methacrylate) (PMMA), are naturally cytophobic and require specific functionalization treatments in order to promote cell adhesion. Through our proposal technique, it’s possible to obtain spontaneous organization and a driven growth of SH-SY5Y cells that is solely dictated by the nature of the charge polymer surface, opening, in this way, the innovative chance to manipulate and transfer biological samples on a free-standing polymer layer [1].

  8. The Defensive Role of Cumulus Cells Against Reactive Oxygen Species Insult in Metaphase II Mouse Oocytes.

    PubMed

    Shaeib, Faten; Khan, Sana N; Ali, Iyad; Thakur, Mili; Saed, Mohammed G; Dai, Jing; Awonuga, Awoniyi O; Banerjee, Jashoman; Abu-Soud, Husam M

    2016-04-01

    We investigated the ability of reactive oxygen species (ROS), such as hydrogen peroxide (H(2)O(2)), hydroxyl radical ((·)OH), and hypochlorous acid (HOCl), to overcome the defensive capacity of cumulus cells and elucidate the mechanism through which ROS differentially deteriorate oocyte quality. Metaphase II mouse oocytes with (n = 1634) and without cumulus cells (n = 1633) were treated with increasing concentration of ROS, and the deterioration in oocyte quality was assessed by the changes in the microtubule morphology and chromosomal alignment. Oocyte and cumulus cell viability and cumulus cell number were assessed by indirect immunofluorescence, staining of gap junction protein, and trypan blue staining. The treated oocytes showed decreased quality as a function of increasing concentrations of ROS when compared to controls. Cumulus cells show protection against H(2)O(2) and (·)OH insult at lower concentrations, but this protection was lost at higher concentrations (>50 μmol/L). At higher H(2)O(2) concentrations, treatment dramatically influenced the cumulus cell number and viability with resulting reduction in the antioxidant capacity making the oocyte more susceptible to oxidative damage. However, cumulus cells offered no significant protection against HOCl at any concentration used. In all circumstances in which cumulus cells did not offer protection to the oocyte, both cumulus cell number and viability were decreased. Therefore, the deterioration in oocyte quality may be caused by one or more of the following: a decrease in the antioxidant machinery by the loss of cumulus cells, the lack of scavengers for specific ROS, and/or the ability of the ROS to overcome these defenses.

  9. LES study of microphysical variability bias in shallow cumulus

    NASA Astrophysics Data System (ADS)

    Kogan, Yefim

    2017-05-01

    Subgrid-scale (SGS) variability of cloud microphysical variables over the mesoscale numerical weather prediction (NWP) model has been evaluated by means of joint probability distribution functions (JPDFs). The latter were obtained using dynamically balanced Large Eddy Simulation (LES) model dataset from a case of marine trade cumulus initialized with soundings from Rain in Cumulus Over the Ocean (RICO) field project. Bias in autoconversion and accretion rates from different formulations of the JPDFs was analyzed. Approximating the 2-D PDF using a generic (fixed-in-time), but variable-in-height JPDFs give an acceptable level of accuracy, whereas neglecting the SGS variability altogether results in a substantial underestimate of the grid-mean total conversion rate and producing negative bias in rain water. Nevertheless the total effect on rain formation may be uncertain in the long run due to the fact that the negative bias in rain water may be counterbalanced by the positive bias in cloud water. Consequently, the overall effect of SGS neglect needs to be investigated in direct simulations with a NWP model.

  10. Steroid production by the cumulus: relationship to fertilization in vitro.

    PubMed

    Hartshorne, G M

    1989-10-01

    Insemination media were collected from 92 follicles of 14 patients stimulated to undergo oocyte retrieval for in-vitro fertilization. Levels of progesterone and oestradiol in the insemination drops were assayed, corrected for carry-over from follicular fluid and volume and expressed as production per microgram of protein in the cumulus. Significantly higher progesterone production per unit protein was associated with oocytes which fertilized in vitro (P less than 0.02). Oocytes fertilizing with subsequent fragmentation or degeneration showed progesterone levels significantly higher than oocytes fertilizing normally (P less than 0.05). Polyspermic oocytes (n = 3) were associated with very high levels of progesterone production but were not significantly different due to the low numbers. Oestradiol production per unit protein was significantly greater in oocytes which fertilized normally than in those which degenerated (P less than 0.05). The protein content of cumuli whose oocytes fertilized appeared to be significantly lower than those which did not (P less than 0.05). These results probably reflect the maturity of the follicle, although direct actions of cumulus products upon the gametes cannot be ruled out.

  11. Tropical Convection and Climate Processes in a Cumulus Ensemble Model

    NASA Technical Reports Server (NTRS)

    Sui, Chung-Hsiung

    1999-01-01

    Local convective-radiative equilibrium states of the tropical atmosphere are determined by the following external forcing: 1) Insolation, 2) Surface heat and moisture exchanges (primarily radiation and evaporation), 3) Heating and moistening induced by large-scale circulation. Understanding the equilibrium states of the tropical atmosphere in different external forcing conditions is of vital importance for studying cumulus parameterization, climate feedbacks, and climate changes. We extend our previous study using the Goddard Cumulus Ensemble (GCE) Model which resolves convective-radiative processes more explicitly than global climate models do. Several experiments are carried out under fixed insolation and sea surface temperature. The prescribed SST consists of a uniform warm pool (29C) surrounded by uniform cold SST (26C). The model produces "Walker"-type circulation with the ascending branch of the model atmosphere more humid than the descending part, but the vertically integrated temperature does not show a horizontal gradient. The results are compared with satellite measured moisture by SSM/I (Special Sensor Microwave/Imager) and temperature by MSU in the ascending and descending tropical atmosphere. The vertically integrated temperature and humidity in the two model regimes are comparable to the observed values in the tropics.

  12. Nearest neighbor spacing of fair weather cumulus clouds

    NASA Technical Reports Server (NTRS)

    Joseph, Joachim H.; Cahalan, Robert F.

    1990-01-01

    Histograms of nearest neighbor spacings of fair weather cumulus at 15 locations over the world's oceans are presented based on the analysis of high resolution Landsat 3 Multispectral Scanner images for amounts of cloud cover ranging from 0.6 to 37.6 percent. These histograms are found to be essentially the same at all locations analyzed, similarly to previous findings on the size distributions and the fractal dimensions of the perimeters for this cloud type. The nearest neighbor spacings are linearly dependent on the effective cloud radii, with a proportionality factor ranging from five to twenty. The histograms peak at about 0.5 km. Nearest-neighbor spacings smaller than about a kilometer, associated with cumulus clouds with an effective radius less than a few hundred meters, have a distribution of cloud centers that is almost indepedent in the horizontal plane and show a tendency for the formation of clumps. Larger spacings of up to thirty kilometers occur and are associated with the larger clouds. These latter spacings are not independent.

  13. Nearest neighbor spacing of fair weather cumulus clouds

    NASA Technical Reports Server (NTRS)

    Joseph, Joachim H.; Cahalan, Robert F.

    1990-01-01

    Histograms of nearest neighbor spacings of fair weather cumulus at 15 locations over the world's oceans are presented based on the analysis of high resolution Landsat 3 Multispectral Scanner images for amounts of cloud cover ranging from 0.6 to 37.6 percent. These histograms are found to be essentially the same at all locations analyzed, similarly to previous findings on the size distributions and the fractal dimensions of the perimeters for this cloud type. The nearest neighbor spacings are linearly dependent on the effective cloud radii, with a proportionality factor ranging from five to twenty. The histograms peak at about 0.5 km. Nearest-neighbor spacings smaller than about a kilometer, associated with cumulus clouds with an effective radius less than a few hundred meters, have a distribution of cloud centers that is almost indepedent in the horizontal plane and show a tendency for the formation of clumps. Larger spacings of up to thirty kilometers occur and are associated with the larger clouds. These latter spacings are not independent.

  14. Technical Support for China's Village Electrification Program: Cooperative Research and Development Final Report, CRADA number CRD-07-00235

    SciTech Connect

    Kline, D.

    2010-07-01

    This work has two main goals: First, it provides for the analysis of data collected from systems developed in the previous phase of China's rural power program, the Township Electrification Program Second, it will comprise joint IEE-NREL work in support of the upcoming phase, 'Electrification of Unelectrified Areas'.

  15. Multi-Criteria Optimization of the Deployment of a Grid for Rural Electrification Based on a Heuristic Method

    NASA Astrophysics Data System (ADS)

    Ortiz-Matos, L.; Aguila-Tellez, A.; Hincapié-Reyes, R. C.; González-Sanchez, J. W.

    2017-07-01

    In order to design electrification systems, recent mathematical models solve the problem of location, type of electrification components, and the design of possible distribution microgrids. However, due to the amount of points to be electrified increases, the solution to these models require high computational times, thereby becoming unviable practice models. This study posed a new heuristic method for the electrification of rural areas in order to solve the problem. This heuristic algorithm presents the deployment of rural electrification microgrids in the world, by finding routes for optimal placement lines and transformers in transmission and distribution microgrids. The challenge is to obtain a display with equity in losses, considering the capacity constraints of the devices and topology of the land at minimal economic cost. An optimal scenario ensures the electrification of all neighbourhoods to a minimum investment cost in terms of the distance between electric conductors and the amount of transformation devices.

  16. Automated Identification of Initial Storm Electrification and End-of-Storm Electrification Using Electric Field Mill Sensors

    NASA Technical Reports Server (NTRS)

    Maier, Launa M.; Huddleston, Lisa L.

    2017-01-01

    Kennedy Space Center (KSC) operations are located in a region which experiences one of the highest lightning densities across the United States. As a result, on average, KSC loses almost 30 minutes of operational availability each day for lightning sensitive activities. KSC is investigating using existing instrumentation and automated algorithms to improve the timeliness and accuracy of lightning warnings. Additionally, the automation routines will be warning on a grid to minimize under-warnings associated with not being located in the center of the warning area and over-warnings associated with encompassing too large an area. This study discusses utilization of electric field mill data to provide improved warning times. Specifically, this paper will demonstrate improved performance of an enveloping algorithm of the electric field mill data as compared with the electric field zero crossing to identify initial storm electrification. End-of-Storm-Oscillation (EOSO) identification algorithms will also be analyzed to identify performance improvement, if any, when compared with 30 minutes after the last lightning flash.

  17. Greenhouse gas implications of fleet electrification based on big data-informed individual travel patterns.

    PubMed

    Cai, Hua; Xu, Ming

    2013-08-20

    Environmental implications of fleet electrification highly depend on the adoption and utilization of electric vehicles at the individual level. Past research has been constrained by using aggregated data to assume all vehicles with the same travel pattern as the aggregated average. This neglects the inherent heterogeneity of individual travel behaviors and may lead to unrealistic estimation of environmental impacts of fleet electrification. Using "big data" mining techniques, this research examines real-time vehicle trajectory data for 10,375 taxis in Beijing in one week to characterize the travel patterns of individual taxis. We then evaluate the impact of adopting plug-in hybrid electric vehicles (PHEV) in the taxi fleet on life cycle greenhouse gas emissions based on the characterized individual travel patterns. The results indicate that 1) the largest gasoline displacement (1.1 million gallons per year) can be achieved by adopting PHEVs with modest electric range (approximately 80 miles) with current battery cost, limited public charging infrastructure, and no government subsidy; 2) reducing battery cost has the largest impact on increasing the electrification rate of vehicle mileage traveled (VMT), thus increasing gasoline displacement, followed by diversified charging opportunities; 3) government subsidies can be more effective to increase the VMT electrification rate and gasoline displacement if targeted to PHEVs with modest electric ranges (80 to 120 miles); and 4) while taxi fleet electrification can increase greenhouse gas emissions by up to 115 kiloton CO2-eq per year with the current grid in Beijing, emission reduction of up to 36.5 kiloton CO2-eq per year can be achieved if the fuel cycle emission factor of electricity can be reduced to 168.7 g/km. Although the results are based on a specific public fleet, this study demonstrates the benefit of using large-scale individual-based trajectory data (big data) to better understand environmental implications

  18. Vegetation-atmosphere interactions and boundary layer cumulus clouds

    NASA Astrophysics Data System (ADS)

    Freedman, Jeffrey Michael

    2000-07-01

    A study of vegetation-atmosphere interactions and boundary layer cumulus clouds (``BLcu'') in terms of seasonal trends (i.e., heat and moisture tendencies) and short-term events (specifically the modification of in situ air masses) is presented. In the northeastern U.S., in response to increasing insolation and sensible heat flux, both the mixed layer height (zi) and lifting condensation level (LCL) peak (~1300 and 1700 m) just before the start of the growing season. With the commencement of transpiration, the Bowen ratio (β) falls abruptly (from greater than 3 to less than 1) as additional moisture is transpired into the boundary layer, and zi and the LCL decrease. By late spring, boundary layer cumulus cloud frequency increases sharply, as the mixed layer approaches a new equilibrium. At Harvard Forest during 1995, afternoon net carbon uptake (Fco2 ) was 52% greater on days with boundary layer cumulus clouds than clear days. For 1996-1998, afternoon Fco2 was also enhanced, especially during dry periods. The same enhancement, albeit reduced, was observed at a northern jack pine site during the BOREAS project, despite very different phenological, hydrological, and climatological regimes. Sixteen frontal sequences affecting the northeastern U.S. were analyzed in terms of local and regional contributions to the temperature and moisture tendency equations. A composite of sequences featuring the daily appearance of BLcu indicates a diminished role for entrainment and other external forcings due to the daily occurrence of a rapid growth phase in ML diurnal evolution subsequent to day 1. From the sequence minimum (day 2) in temperature and moisture, surface flux convergence accounts for about 50% of the overall net moistening and heating of the mixed layer. Model sensitivity tests show that changes in subsidence and γ θν affect ML processes most on day 1; dining subsequent days, the rapid growth phase dominates the ML growth equation, and reduces the impact of these

  19. Automated test bench for simulation of radiation electrification of spacecraft structural dielectrics

    NASA Astrophysics Data System (ADS)

    Vladimirov, A. M.; Bezhayev, A. Yu; Zykov, V. M.; Isaychenko, V. I.; Lukashchuk, A. A.; Lukonin, S. E.

    2017-01-01

    The paper describes the test bench “Prognoz-2” designed in Testing Center, Institute of Non-Destructive Testing, Tomsk Polytechnic University, which can be used: for ground testing of individual samples of spacecraft structural materials (e.g. thermal control coatings or cover glasses for solar batteries) or ceramics of the plasma thruster discharge channel), and whole spacecraft units or instruments (e.g. instruments of solar and stellar orientation or correcting plasma thrusters) exposed to radiation electrification factors; to verify the calculation mathematical models of radiation electrification of structural dielectrics under the impact of space factors in different orbits.

  20. In vitro maturation impacts cumulus oocyte complex metabolism and stress in cattle.

    PubMed

    Del Collado, Maite; da Silveira, Juliano Coelho; Oliveira, Marcelo Luna Freire; Alves, Barbara Monteiro da Silva Marques; Simas, Rosineide Costa; Godoy, Adriana Teixeira; Coelho, Mirela Batista; Marques, Lygia Azevedo; Carriero, Mateus Maldonado; Nogueira, Marcelo Fábio Gouveia; Eberlin, Marcos Nogueira; Silva, Luciano A; Meirelles, Flávio Vieira; Perecin, Felipe

    2017-10-02

    The influence of in vitro maturation (IVM) in oocytes is still not totally understood. The aim of this study was to determine the influence of IVM on the metabolism and homeostasis of bovine cumulus-oocyte complexes. In the present study, we demonstrated that IVM leads to accumulation of neutral lipids associated with differential levels of the mono-, di-, and tri-acylglycerols in both cumulus cells and oocytes. We observed that in vitro-matured oocytes exhibited decreased glutathione and reactive oxygen species levels and a lower ATP/ADP ratio when compared to in vivo-matured oocytes, with no significant differences in metabolism and stress related mRNA or miRNA levels. Moreover, in addition to an increase in lipids in in vitro-matured cumulus cells, fatty acid synthesis and accumulation as well as glycolysis pathway genes were upregulated, whereas those affiliated with the -oxidation pathway were decreased. Our gene expression data in cumulus cells suggest the disruption of endoplasmic reticulum stress, apoptosis, and cellular stress response pathways during IVM. Furthermore, a total of 19 miRNAs were significantly altered by the maturation process in cumulus cells. These results indicate some new negative influences of the in vitro system in cumulus-oocyte complexes, demonstrating the occurrence of functional disruption in lipid metabolism and stress pathways and showing evidences suggesting the occurrence of altered mitochondrial activity and energy metabolism during IVM, with a massive dysregulation of the corresponding transcripts in the surrounding cumulus cells.

  1. Specific gene expression differences in cumulus cells as potential biomarkers of pregnancy.

    PubMed

    Burnik Papler, Tanja; Vrtačnik Bokal, Eda; Maver, Aleš; Lovrečić, Luca

    2015-04-01

    The development of an objective and accurate test that could help select embryos with the highest chance of achieving pregnancy in IVF procedures is an important goal of reproductive medicine. For this purpose, cumulus cell gene expression is being studied to find biomarkers of pregnancy. Several recent studies have proposed potential biomarkers of pregnancy expressed in cumulus cells; however, these have mostly not been validated on an independent set of samples. The aim of this study was to analyse the expression of EFNB2, RGS2 and VCAN genes proposed as biomarkers of pregnancy in cumulus cells by quantitative polymerase chain reaction. Gene expression was evaluated in 43 individual cumulus cell samples, derived from a highly homogenous group of 43 women. The same protocol for ovarian stimulation was used for all women, and elective single embryo transfer was performed. Expression levels of RGS2 and VCAN did not differ between cumulus cells of implanted and non-implanted embryos. EFNB2 showed borderline higher expression in cumulus cells of non-implanted embryos, which is contradictory to previous studies. Altogether, the results of previous studies in which EFNB2, RGS2 and VCAN were proposed as biomarkers of pregnancy could not be replicated in our set of cumulus cell samples.

  2. PTGS2 down-regulation in cumulus cells of infertile women with endometriosis.

    PubMed

    da Luz, Caroline M; da Broi, Michele G; Donabela, Flávia Cappello; Paro de Paz, Cláudia Cristina; Meola, Juliana; Navarro, Paula A

    2017-07-10

    A deleterious effect of endometriosis on oocyte quality has been proposed. Evidence suggests that cumulus cells could be used as indirect biomarkers of oocyte quality. The PTGS2 gene, which encodes cyclooxygenase 2 (COX-2), is deregulated in endometriotic lesions and plays a crucial role in the acquisition of oocyte competence. To date, research evaluating PTGS2 expression in cumulus cells of infertile patients with endometriosis has not been conducted. The aim this study was to compare the expression levels of PTGS2 in cumulus cells of infertile women, with and without endometriosis, undergoing ovarian stimulation for intracytoplasmic sperm injection (ICSI). Therefore, a case-control study compared PTGS2 gene expression in the cumulus cells of 38 infertile patients with endometriosis and 40 without, using real-time polymerase chain reaction. For the first time, decreased expression of PTGS2 was found in cumulus cells of infertile women with endometriosis compared with controls (7.2 ± 10.5 versus 12.4 ± 15.7), which might be related to reduced levels of COX-2 in the cumulus cells of women with the disease. Consequently, we hypothesize that lower transcript levels of PTGS2 in cumulus cells may be involved in the impairment of oocyte quality, suggesting a possible mechanism involved in disease-related infertility. Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  3. Processes causing electrification of ice crystals in thunderclouds

    NASA Astrophysics Data System (ADS)

    Vonnegut, B.; Moore, C. B.

    Jayaratne and Saunders (1991) have performed a useful service by reporting their laboratory experiments demonstrating, contrary to the findings of Odencrantz and Buecher (1967), that ice crystal charging does not take place in an unmixed cloud of ice crystals. Jayaratne and Saunders' further cold box experiments showing that the ice crystals become electrified when a fan in the cold box is turned on, support their view that an ice-ice charging process takes place on the surfaces of the moving ice-covered fan-blades. Their conclusion, that this phenomenon might be capable of producing each second the several coulombs of charged cloud particles necessary to maintain the electrification of a thundercloud, appears justified. However, because their paper is lacking in experimental details and because it is unknown whether the conditions in their cold chamber accurately duplicate those in a thunderstorm, this point is not possible to resolve. There is good reason to doubt J and S's final conclusion, that "… in thunderstorms, ice crystal charges are similarly acquired by collision processes RATHER THAN BY ANY OTHER MECHANISM". It is puzzling to understand why the authors have chosen to ignore ion attachment, an important ice crystal charging process that does not involve collisions between ice crystals. Beginning with Gish and Wait (1950), numerous investigators have demonstrated that ion currents flow to the tops of thunderclouds as predicted by Wilson (1920). Marshall et al. (1989) and Byrne et al. (1989) have found that ice particles at cloud top carry appreciable charges that appear to be derived from the Wilson current. In an average storm there can be little doubt that this mechanism too could be producing charged ice crystals at the required rate of about a coulomb per second (Vonnegut, 1990).

  4. Transportation Electrification Load Development For a Renewable Future Analysis

    SciTech Connect

    Markel, Tony; Mai, Trieu; Kintner-Meyer, Michael CW

    2010-09-30

    Electrification of the transportation sector offers the opportunity to significantly reduce petroleum consumption. The transportation sector accounts for 70% of US petroleum consumption. The transition to electricity as a transportation fuel will create a new load for electricity generation. In support of a recent US Department of Energy funded activity that analyzed a future generation scenario with high renewable energy technology contributions, a set of regional hourly load profiles for electrified vehicles were developed for the 2010 to 2050 timeframe. These load profiles with their underlying assumptions will be presented in this paper. The transportation electrical energy was determined using regional population forecast data, historical vehicle per capita data, and market penetration growth functions to determine the number of plug-in electric vehicles (PEVs) in each analysis region. Two market saturation scenarios of 30% of sales and 50% of sales of PEVs consuming on average {approx}6 kWh per day were considered. Results were generated for 3109 counties and were consolidated to 134 Power Control Areas (PCA) for the use NREL's's regional generation planning analysis tool ReEDS. PEV aggregate load profiles from previous work were combined with vehicle population data to generate hourly loads on a regional basis. A transition from consumer-controlled charging toward utility-controlled charging was assumed such that by 2050 approximately 45% of the transportation energy demands could be delivered across 4 daily time slices under optimal control from the utility perspective. No other literature has addressed the potential flexibility in energy delivery to electric vehicles in connection with a regional power generation study. This electrified transportation analysis resulted in an estimate for both the flexible load and fixed load shapes on a regional basis that may evolve under two PEV market penetration scenarios. EVS25 Copyright.

  5. Impact of detrained cumulus on climate simulated by the Community Atmosphere Model Version 5 with a unified convection scheme

    NASA Astrophysics Data System (ADS)

    Park, Sungsu; Baek, Eun-Hyuk; Kim, Baek-Min; Kim, Seong-Joong

    2017-06-01

    Cumulus elements generated by detraining convective condensate-detrained cumulus-are added to the Community Atmosphere Model Version 5 (CAM5) combined with a Unified Convection Scheme (UNICON). Instead of evaporating convective liquids detrained into clear portions, we diagnosed a new detrained cumulus that is horizontally nonoverlapped with cumulus and stratus in each layer by assuming a steady state balance between the detrainment rate of cumulus condensates and the dissipation rate of detrained condensates by entrainment mixing with environmental air. The addition of detrained cumulus was found to substantially improve the simulation of low-level clouds and the associated shortwave cloud radiative forcing, particularly in the subtropical trade cumulus regime. In addition to the mean climate, successful simulations of the diurnal cycle of precipitation, Madden-Julian Oscillation, and Kelvin wave were also well maintained.

  6. Cumulus convection as observed from an airborne infrared radiometer

    NASA Technical Reports Server (NTRS)

    Szejwach, G.; Simpson, J.

    1982-01-01

    The implementation of high resolution passive radiative remote sensing of the cloudiness volume in the atmospheric window between 10.5-12.5 microns is described. Airborne radiometers, the NASA/Cloud Top Scanner, were used to obtain radiances during several passages over two merging cumulus clouds, with the data being converted into equivalent blackbody temperatures. Data were also gathered in the 0.55-0.70 micron visible bands as part of the SESAME-79 experiment. The number of points observed in the IR channel were adjusted to account for the viewing angle and areal extents were calculated. A relationship was assumed to exist between the brightness temperatures of the cloud surface and the level of cloudiness at a given atmospheric altitude. Further measurements with lidar scans are indicated in order to reduce the error levels associated with the method.

  7. Small-Scale Variability in Warm Continental Cumulus Clouds.

    NASA Astrophysics Data System (ADS)

    Austin, P. H.; Baker, M. B.; Blyth, A. M.; Jensen, J. B.

    1985-06-01

    We have analyzed small-scale fluctuations in microphysical, dynamical and thermodynamical parameters measured in two warm cumulus clouds during the Cooperative Convective Precipitation Experiment (CCOPE) project (1981) in light of predictions of several recent models. The measurements show the existence at all levels throughout the sampling period of two statistically distinct kinds of cloudy regions, termed `variable' and `steady,' often separated by transition zones of less than ten meters. There is some evidence for microphysical variability induced by local fluctuations in thermodynamic and dynamic parameters; however, the predominant variations are of a nature consistent with laboratory evidence suggesting that mixing is dominated by large structures. Entrainment appears to occur largely near cloud top but the data presented here do not permit identification of a mechanism for transport of the entrained air throughout the cloud.

  8. A New Approach for Estimating Entrainment Rate in Cumulus Clouds

    SciTech Connect

    Lu C.; Liu, Y.; Yum, S. S.; Niu, S.; Endo, S.

    2012-02-16

    A new approach is presented to estimate entrainment rate in cumulus clouds. The new approach is directly derived from the definition of fractional entrainment rate and relates it to mixing fraction and the height above cloud base. The results derived from the new approach compare favorably with those obtained with a commonly used approach, and have smaller uncertainty. This new approach has several advantages: it eliminates the need for in-cloud measurements of temperature and water vapor content, which are often problematic in current aircraft observations; it has the potential for straightforwardly connecting the estimation of entrainment rate and the microphysical effects of entrainment-mixing processes; it also has the potential for developing a remote sensing technique to infer entrainment rate.

  9. Diurnal timescale feedbacks in the tropical cumulus regime

    NASA Astrophysics Data System (ADS)

    Ruppert, James H.

    2016-09-01

    Although the importance of the diurnal cycle in modulating clouds and precipitation has long been recognized, its impact on the climate system at longer timescales has remained elusive. Mounting evidence indicates that the diurnal cycle may substantially affect leading climate modes through nonlinear rectification. In this study, an idealized cloud-resolving model experiment is executed to isolate a diurnal timescale feedback in the shallow cumulus regime over the tropical warm pool. This feedback is isolated by modifying the period of the diurnal cycle (or removing it), which proportionally scales (or removes) the diurnal thermodynamic forcing that clouds respond to. This diurnal forcing is identified as covarying cycles of static stability and humidity in the lower troposphere, wherein the most unstable conditions coincide with greatest humidity each afternoon. This diurnal forcing yields deeper clouds and greater daily-mean cumulus heating than would otherwise occur, in turn reducing large-scale subsidence from day to day according to the "weak temperature gradient" approximation. This diurnal forcing therefore manifests as a timescale feedback by accelerating the onset of deep convection. The longwave cloud-radiation effect is found to amplify this timescale feedback, since the resulting invigoration of clouds (increased upper-cloud radiative cooling, with suppressed cooling below) scales with cloud depth (i.e., optical thickness), and hence with the magnitude of diurnal forcing. These findings highlight the pressing need to remedy longstanding problems related to the diurnal cycle in many climate models. Given the evident sensitivity of climate variability to diurnal processes, doing so may yield advances in climate prediction at longer timescales.

  10. Observations of Homogeneous and Inhomogeneous Mixing in Warm Cumulus Clouds

    NASA Astrophysics Data System (ADS)

    Lehmann, K.; Siebert, H.; Shaw, R. A.

    2007-12-01

    The helicopter-borne instrument payload ACTOS was used to study the entrainment/mixing process in shallow warm cumulus clouds. Using ACTOS, high resolution measurements of the three-dimensional wind, temperature and humidity fields were made. In addition, cloud microphysical parameters such as the droplet number concentration and size were measured with a modified Fast-FSSP. The effect of entrained subsaturated air on the droplet number size distribution was analyzed using mixing diagrams which correlate droplet number concentration and droplet size. Both homogeneous and inhomogeneous mixing was observed to take place. The characteristic of the mixing process is compared to the Damköhler number. The Damköhler number is given by the ratio of the timescale for turbulent mixing and the reaction timescale, which is either the time for droplet evaporation, or the phase relaxation timescale. With ACTOS' instrumentation, the Damköhler number can be determined with a spatial resolution of about 15 m. In agreement with literature, low values of the Damköhler number correlate with the homogeneous mixing scenario, while higher values of the Damköhler number correlate with the inhomogeneous mixing scenario. It is shown that even within one cloud, different mixing scenarios can take place. The data suggest that homogeneous mixing is more likely to occur in the vicinity of the vigorous cloud core, while inhomogeneous mixing dominates in the outer, less turbulent part of the cloud. A case is presented in which the mixing led to the formation of drops that are larger than in the unmixed adiabatic core. This is of potential importance for precipitation formation in warm cumulus clouds.

  11. Interactions between oocytes and cumulus cells during in vitro maturation of porcine cumulus-oocyte complexes in a chemically defined medium: effect of denuded oocytes on cumulus expansion and oocyte maturation.

    PubMed

    Appeltant, R; Somfai, T; Nakai, M; Bodó, S; Maes, D; Kikuchi, K; Van Soom, A

    2015-03-01

    The aim of the present study was to clarify interactions between oocytes and cumulus cells (CCs) on the level of cumulus expansion and oocyte maturation during IVM of cumulus-oocyte complexes (COCs) in a chemically defined medium using a system that allows individual tracking of oocytes. Especially, the influence of oocyte-secreted factors was investigated by the aid of addition of denuded oocytes (DOs) as a possible approach to improve the IVM system. The basic maturation medium was porcine oocyte medium with addition of gonadotropins only during the first 20 hours of IVM. During IVM, COCs were kept fixed to the bottom of culture dish by adhesive Cell-Tak coating, which enabled individual tracking of COCs during IVM. Size changes in COCs during IVM were measured by digital image analysis. Cumulus expansion in a porcine oocyte medium of intact COCs increased in a typical manner until 20 hours and decreased in size subsequently until 48 hours of IVM (P < 0.05). Removal of oocytes from COCs by oocytectomy allowed the expansion of CCs to some extent, although their expansion ability was lower than that of COCs (P < 0.05). Addition of DOs (COCs to DOs ratio of 9:16) did not improve cumulus expansion and oocyte maturation rates of intact COCs (P > 0.05) but did enhance cumulus expansion of oocytectomized complexes (P < 0.05). Furthermore, removal of CCs before IVM increased oocyte maturation rates compared with COCs (52.3% and 32.9%, respectively) (P < 0.05) and a similar effect was observed in COCs when the gap junction inhibitor carbenoxolone was added to the IVM medium: carbenoxolone repressed the expansion of COCs at 20 hours of IVM. In conclusion, the porcine oocyte enhances cumulus expansion both by gap junctional communications and presumably by oocyte-secreted factor production. Nevertheless, the presence of oocytes is not a prerequisite for this process. In return, CCs maintain meiotic arrest in cumulus-enclosed oocytes during the initial culture

  12. Earth Science

    NASA Image and Video Library

    2002-08-01

    A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely-piloted aircraft to study thunderstorms in the Atlantic Ocean off Key West and the west of the Everglades. Using special equipment aboard the Altus II, scientists in ACES will gather electric, magnetic, and optical measurements of the thunderstorms, gauging elements such as lightning activity and the electrical environment in and around the storms. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the Marshall Space Flight Center, the University of Alabama in Huntsville, NASA's Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

  13. Direct probing of contact electrification by using optical second harmonic generation technique

    PubMed Central

    Chen, Xiangyu; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa; Wang, Zhong Lin

    2015-01-01

    Contact electrification between two different materials is one of the oldest fields of study in solid-state physics. Here, we introduced an innovative system based on optical electric-field-induced second harmonic generation (EFI-SHG) technique that can directly monitor the dynamic performance of the contact electrification on the surface of polyimide film. After the contact, the EFI-SHG system visualized briefly three relaxations of the tribo-induced charges on the surface of a polyimide film, a fast relaxation within 3 min followed by two much slower relaxations, which were possibly related to different charge diffusion routes. The contact electrification under several special experimental conditions (wind, water and steam) was studied to demonstrate the high flexibility and material selectivity of the EFI-SHG. The EFI-SHG studies confirmed the motion of the water can remove the surface charge, while the appearance and the evaporation of a thin water layer cannot enhance the charge diffusion. We anticipate that this experimental technique will find a variety of applications in the field of contact electrification and the development of the recently invented triboelectric nano generator. PMID:26272162

  14. Lighting up the World The first global application of the open source, spatial electrification toolkit (ONSSET)

    NASA Astrophysics Data System (ADS)

    Mentis, Dimitrios; Howells, Mark; Rogner, Holger; Korkovelos, Alexandros; Siyal, Shahid; Broad, Oliver; Zepeda, Eduardo; Bazilian, Morgan

    2016-04-01

    In September 2015, the international community has adopted a new set of targets, following and expanding on the millennium development goals (MDGs), the Sustainable Development Goals (SDGs). Ensuring access to affordable, reliable, sustainable and modern energy for all is one of the 17 set goals that each country should work towards realizing. According to the latest Global Tracking Framework, 15% of the global population live without access to electricity. The majority of those (87%) reside in rural areas. Countries can reach universal access through various electrification options, depending on different levels of energy intensity and local characteristics of the studied areas, such as renewable resources availability, spatially differentiated costs of diesel-fuelled electricity generation, distance from power network and major cities, population density and others, data which are usually inadequate in national databases. This general paucity of reliable energy-related information in developing countries calls for the utilization of geospatial data. This paper presents a Geographic Information Systems (GIS) based electrification analysis for all countries that have not yet reached full access to electricity (Sub-Saharan Africa, Developing Asia, Latin America and Middle East). The cost optimal mix of electrification options ranges from grid extensions to mini-grid and stand-alone applications and is identified for all relevant countries. It is illustrated how this mix is influenced by scrolling through various electrification levels and different oil prices. Such an analysis helps direct donors and investors and inform multinational actions with regards to investments related to energy access.

  15. Direct probing of contact electrification by using optical second harmonic generation technique

    NASA Astrophysics Data System (ADS)

    Chen, Xiangyu; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa; Wang, Zhong Lin

    2015-08-01

    Contact electrification between two different materials is one of the oldest fields of study in solid-state physics. Here, we introduced an innovative system based on optical electric-field-induced second harmonic generation (EFI-SHG) technique that can directly monitor the dynamic performance of the contact electrification on the surface of polyimide film. After the contact, the EFI-SHG system visualized briefly three relaxations of the tribo-induced charges on the surface of a polyimide film, a fast relaxation within 3 min followed by two much slower relaxations, which were possibly related to different charge diffusion routes. The contact electrification under several special experimental conditions (wind, water and steam) was studied to demonstrate the high flexibility and material selectivity of the EFI-SHG. The EFI-SHG studies confirmed the motion of the water can remove the surface charge, while the appearance and the evaporation of a thin water layer cannot enhance the charge diffusion. We anticipate that this experimental technique will find a variety of applications in the field of contact electrification and the development of the recently invented triboelectric nano generator.

  16. Laboratory studies of aerosol electrification and experimental evidence for electrical breakdown at different scales.

    NASA Astrophysics Data System (ADS)

    Alois, Stefano; Merrison, Jonathan; Iversen, Jens Jacob; Sesterhenn, Joern

    2017-04-01

    Contact electrification between different particles size/material can lead to electric field generation high enough to produce electrical breakdown. Experimental studies of solid aerosol contact electrification (Alois et al., 2016) has shown various electrical breakdown phenomena; these range from field emission at the contact site (nm-scale) limiting particle surface charge concentration, to visible electrical discharges (cm-scale) observed both with the use of an electrometer and high-speed camera. In these experiments micron-size particles are injected into a low-pressure chamber, where they are deviated by an applied electric field. A laser Doppler velocimeter allows the simultaneous determination of particle size and charge of single grains. Results have shown an almost constant surface charge concentration, which is likely to be due to charge limitation by field emission at the contact site between particle and injector. In a second measurement technique, the electrically isolated injector tube (i.e. a Faraday cage) is connected to an oscilloscope and synchronised to a high speed camera filming the injection. Here the electrification of a large cloud of particles can be quantified and discharging effects studied. This study advances our understanding on the physical processes leading to electrification and electrical breakdown mechanisms.

  17. Post-dispersion electrification of droplets in a system with pneumatic atomization

    NASA Astrophysics Data System (ADS)

    Kacprzyk, R.; Lewandowski, M.

    2011-06-01

    The process of electrifying aerosol particles dispersed by a pneumatic sprayer with supersonic air flow is presented. To avoid the electric-field shielding effect, confirmed by investigations of induction charging of aerosol droplets with application of a concentric induction electrode placed in the region of liquid dispersion, the droplet electrification process following the dispersion of liquid was proposed. The supersonic atomizing head was equipped with an external high voltage contact electrode placed concentrically and perpendicularly to the droplets stream and closely to the atomizing head. Experiments were conducted in air, at ambient conditions (T = 18±2 °C, RH = 55±3%), for standard air feeding rate (0.5 m3/min, 0.4 MPa) and regulated dispersed liquid rate (0.1 - 0.55 l/min). Results of the applied electrification process, characterized by a (Q/m) factor measured as a function of liquid feed rate, have shown that the (Q/m) values achieved for post-dispersion electrification are comparable to the values obtained for typical induction electrification with application of a concentric electrode.

  18. A Generalized Simple Formulation of Convective Adjustment Timescale for Cumulus Convection Parameterizations

    EPA Science Inventory

    Convective adjustment timescale (τ) for cumulus clouds is one of the most influential parameters controlling parameterized convective precipitation in climate and weather simulation models at global and regional scales. Due to the complex nature of deep convection, a pres...

  19. The possible FAT1-mediated apoptotic pathways in porcine cumulus cells.

    PubMed

    Wu, Xinhui; Fu, Yao; Sun, Xulei; Liu, Chang; Chai, Menglong; Chen, Chengzhen; Dai, Lisheng; Gao, Yan; Jiang, Hao; Zhang, Jiabao

    2017-01-01

    Porcine cumulus cells are localized around oocytes and act as a specific type of granulosa that plays essential roles in the development and maturation of oocytes, the development and atresia of follicles, and the development of embryos. Studies of FAT1 have demonstrated its functions in cell-cell contact, actin dynamics, and cell growth suppression. To understand whether the FAT1 gene affects the apoptosis of porcine cumulus cells and to elucidate the mechanism of this potential action, FAT1 was knocked down using RNA interference. The lack of FAT1 resulted in stable expression of CTNNB, enhanced expression of cleaved CASP3, but decreased the BCL2/BAX ratios at both the mRNA and protein levels. These results indicated that FAT1 inhibited porcine cumulus cell apoptosis via different pathways. Taken together, these data provide new insights into the mechanisms of the association between FAT1 and porcine cumulus cell apoptosis.

  20. Clustered or regular cumulus cloud fields - The statistical character of observed and simulated cloud fields

    NASA Technical Reports Server (NTRS)

    Ramirez, Jorge A.; Bras, Rafael L.

    1990-01-01

    The spatial distribution of cumulus clouds is assumed to be the result of the effects of convective activity on the thermodynamic environment. The effects can be parameterized in terms of a stabilization function representing the time rate of change of convective available potential energy. Using these results, a new inhibition hypothesis explaining the expected characteristics of the spatial distribution of cumulus clouds is postulated. This paper performs a verification of the inhibition hypothesis on real and simulated cloud fields. In order to do so, an objective measure of the spatial characteristics of cumulus clouds is introduced. Multiple cloud experiments are performed with a three-dimensional numerical cloud model. Skylab pictures of real cumuli are also used in the verification. Results of applying this measure to simulated and observed cumulus cloud fields confirm the inhibition hypothesis.

  1. Comparison of Irrigation Water Use Estimates Calculated from Remotely Sensed Irrigated Acres and State Reported Irrigated Acres in the Lake Altus Drainage Basin, Oklahoma and Texas, 2000 Growing Season

    USGS Publications Warehouse

    Masoner, J.R.; Mladinich, C.S.; Konduris, A.M.; Smith, S. Jerrod

    2003-01-01

    Increased demand for water in the Lake Altus drainage basin requires more accurate estimates of water use for irrigation. The U.S. Geological Survey, in cooperation with the U.S. Bureau of Reclamation, is investigating new techniques to improve water-use estimates for irrigation purposes in the Lake Altus drainage basin. Empirical estimates of reference evapotranspiration, crop evapotranspiration, and crop irrigation water requirements for nine major crops were calculated from September 1999 to October 2000 using a solar radiation-based evapotranspiration model. Estimates of irrigation water use were calculated using remotely sensed irrigated crop acres derived from Landsat 7 Enhanced Thematic Mapper Plus imagery and were compared with irrigation water-use estimates calculated from irrigated crop acres reported by the Oklahoma Water Resources Board and the Texas Water Development Board for the 2000 growing season. The techniques presented will help manage water resources in the Lake Altus drainage basin and may be transferable to other areas with similar water management needs. Irrigation water use calculated from the remotely sensed irrigated acres was estimated at 154,920 acre-feet; whereas, irrigation water use calculated from state reported irrigated crop acres was 196,026 acre-feet, a 23 percent difference. The greatest difference in irrigation water use was in Carson County, Texas. Irrigation water use for Carson County, Texas, calculated from the remotely sensed irrigated acres was 58,555 acrefeet; whereas, irrigation water use calculated from state reported irrigated acres was 138,180 acre-feet, an 81 percent difference. The second greatest difference in irrigation water use occurred in Beckham County, Oklahoma. Differences between the two irrigation water use estimates are due to the differences of irrigated crop acres derived from the mapping process and those reported by the Oklahoma Water Resources Board and Texas Water Development Board.

  2. SELCO: A model for solar rural electrification in India

    NASA Astrophysics Data System (ADS)

    Hande, H. Harish

    1999-11-01

    The following thesis presents the concept of a Rural Energy Service Company in India, known as SELCO. The model is being set up as a sustainable proposition for the implementation of solar photovoltaics as a viable alternative to provide reliable home lighting in the rural areas of India. The SELCO approach has already achieved noteworthy social and commercial results. Institutional, policy and operational problems have long plagued the rural electrification programs in India, resulting in thousands of villages without access to electricity. SELCO is a solar energy service company operating in Southern India since 1995, focusing on the enormous untapped market for home lighting where thousands of households have no access to electricity and severe power shortages face those already connected to the electric grid. The Company has installed nearly 2,000 solar home lighting systems. From a modest two employees company in 1995, it has grown to 35 in 1997 and from one office to eight. The hypothesis to be tested in this study is that in rural India, in a market not subsidized by the government, a solar service company with available loans from local banks and cooperatives and with sales, installation, and maintenance personnel in the villages can be successful in introducing photovoltaic systems to provide basic amenities such as lighting and water pumping for the improvement of the quality of life, public health, and the environment. The initial success of SELCO lends considerable evidence to the acceptance of the hypothesis. To accomplish its mission, SELCO works with commercial, retail, and rural development banks with large rural branch networks to stimulate loans to SELCO's customers based on a standard set of attractive financing terms. SELCO through its successful model has convinced the policy makers that a way to increase rural families' access to consumer financing for solar home lighting systems is through the existing financial network available in the

  3. Prolactin affects bovine oocytes through direct and cumulus-mediated pathways.

    PubMed

    Lebedeva, Irina Y; Singina, Galina N; Volkova, Natalia A; Vejlsted, Morten; Zinovieva, Natalia A; Schmidt, Mette

    2014-11-01

    The available evidence points to participation of PRL in regulation of mammalian oocyte maturation. The aim of the present study was to characterize pathways of PRL action on bovine oocytes. We analyzed (1) the presence of the PRL receptor and its mRNA isoforms in oocytes and cumulus cells; (2) the effect of PRL on meiosis resumption and the role of cumulus cells, the NO/NO synthase system, protein kinase C, and tyrosine kinases in this effect; and (3) PRL effects in the presence of gonadotropins on the developmental capacity of cumulus-free and cumulus-enclosed oocytes. The transcript and protein expression of the PRL receptor in the cells were detected by reverse transcription polymerase chain reaction and immunocytochemistry, respectively. The nuclear status of oocytes was assessed after culture of cumulus-oocyte complexes (COCs) and denuded oocytes (DOs) with or without PRL (5-500 ng/mL) for 7, 14, or 24 hours. Besides, DOs were incubated for 7 hours in the absence or the presence of PRL (50 ng/mL) and/or L-NAME (an inhibitor of NO synthase), genistein (an inhibitor of tyrosine kinases), or calpostin C (a protein kinase C inhibitor). After IVM in 2 different systems containing PRL (50 ng/mL) and/or gonadotropic hormones, a part of oocytes underwent IVF and IVC and the embryo development was tracked until the blastocyst stage. Messenger RNA of long and short isoforms of the PRL receptor was revealed in both oocytes and cumulus cells. Immunocytochemistry confirmed the presence of the PRL receptor in oocytes and the cumulus investment. In the absence of gonadotropins (system 1), PRL retarded meiosis resumption in DOs but not in cumulus-enclosed oocytes, with this effect being short term, dose dependent, suppressed by L-NAME and genistein, and unaffected by calpostin. In systems containing gonadotropins, PRL did not affect nuclear maturation and the cleavage rate of cumulus-free and cumulus-enclosed oocytes. However, in the case of COCs, it raised the blastocyst

  4. Wind-blown Sand Electrification Inspired Triboelectric Energy Harvesting Based on Homogeneous Inorganic Materials Contact: A Theoretical Study and Prediction

    PubMed Central

    Hu, Wenwen; Wu, Weiwei; Zhou, Hao-miao

    2016-01-01

    Triboelectric nanogenerator (TENG) based on contact electrification between heterogeneous materials has been widely studied. Inspired from wind-blown sand electrification, we design a novel kind of TENG based on size dependent electrification using homogeneous inorganic materials. Based on the asymmetric contact theory between homogeneous material surfaces, a calculation of surface charge density has been carried out. Furthermore, the theoretical output of homogeneous material based TENG has been simulated. Therefore, this work may pave the way of fabricating TENG without the limitation of static sequence. PMID:26817411

  5. Wind-blown Sand Electrification Inspired Triboelectric Energy Harvesting Based on Homogeneous Inorganic Materials Contact: A Theoretical Study and Prediction

    NASA Astrophysics Data System (ADS)

    Hu, Wenwen; Wu, Weiwei; Zhou, Hao-Miao

    2016-01-01

    Triboelectric nanogenerator (TENG) based on contact electrification between heterogeneous materials has been widely studied. Inspired from wind-blown sand electrification, we design a novel kind of TENG based on size dependent electrification using homogeneous inorganic materials. Based on the asymmetric contact theory between homogeneous material surfaces, a calculation of surface charge density has been carried out. Furthermore, the theoretical output of homogeneous material based TENG has been simulated. Therefore, this work may pave the way of fabricating TENG without the limitation of static sequence.

  6. A statistical analysis of the dependency of closure assumptions in cumulus parameterization on the horizontal resolution

    SciTech Connect

    Xu, K.M.

    1994-12-01

    Simulated data from the UCLA cumulus ensemble model are used to investigate the quasi-universal validity of closure assumptions used in existing cumulus parameterizations. A closure assumption is quasi-universally valid if it is sensitive neither to convective cloud regimes nor to horizontal resolutions of large-scale/mesoscale models. The dependency of three types of closure assumptions, as classified by Arakawa and Chen, on the horizontal resolution is addressed in this study. Type I is the constraint on the coupling of the time tendencies of large-scale temperature and water vapor mixing ratio. Type II is the constraint on the coupling of cumulus heating and cumulus drying. Type III is a direct constraint on the intensity of a cumulus ensemble. The macroscopic behavior of simulated cumulus convection is first compared with the observed behavior in view of Type I and Type II closure assumptions using `quick-look` and canonical correlation analyses. It is found that they are statistically similar to each other. The three types of closure assumptions are further examined with simulated data averaged over selected subdomain sizes ranging from 64 to 512 km. It is found that the dependency of Type I and Type II closure assumptions on the horizontal resolution is very weak and that Type III closure assumption is somewhat dependent upon the horizontal resolution. The influences of convective and mesoscale processes on the closure assumptions are also addressed by comparing the structures of canonical components with the corresponding vertical profiles in the convective and stratiform regions of cumulus ensembles analyzed directly from simulated data. The implication of these results for cumulus parameterization is discussed.

  7. Characterization of the human cumulus cell transcriptome during final follicular maturation and ovulation.

    PubMed

    Yerushalmi, G M; Salmon-Divon, M; Yung, Y; Maman, E; Kedem, A; Ophir, L; Elemento, O; Coticchio, G; Dal Canto, M; Mignini Renzinu, M; Fadini, R; Hourvitz, A

    2014-08-01

    Cumulus expansion and oocyte maturation are central processes in ovulation. Knowledge gained from rodent and other mammalian models has revealed some of the molecular pathways associated with these processes. However, the equivalent pathways in humans have not been thoroughly studied and remain unidentified. Compact cumulus cells (CCs) from germinal vesicle cumulus oocyte complexes (COCs) were obtained from patients undergoing in vitro maturation (IVM) procedures. Expanded CCs from metaphase 2 COC were obtained from patients undergoing IVF/ICSI. Global transcriptome profiles of the samples were obtained using state-of-the-art RNA sequencing techniques. We identified 1746 differentially expressed (DE) genes between compact and expanded CCs. Most of these genes were involved in cellular growth and proliferation, cellular movement, cell cycle, cell-to-cell signaling and interaction, extracellular matrix and steroidogenesis. Out of the DE genes, we found 89 long noncoding RNAs, of which 12 are encoded within introns of genes known to be involved in granulosa cell processes. This suggests that unique noncoding RNA transcripts may contribute to the regulation of cumulus expansion and oocyte maturation. Using global transcriptome sequencing, we were able to generate a library of genes regulated during cumulus expansion and oocyte maturation processes. Analysis of these genes allowed us to identify important new genes and noncoding RNAs potentially involved in COC maturation and cumulus expansion. These results may increase our understanding of the process of oocyte maturation and could ultimately improve the efficacy of IVM treatment.

  8. Effect of gonadotrophins, oestradiol and insulin on cumulus expansion of Nili Ravi buffalo oocytes.

    PubMed

    Shahid, Beenish; Jalali, Samina; Khan, Muhamad Ijaz; Shami, Sa

    2015-01-01

    The objective of the present study was to investigate the cumulus expansions of Nili Ravi buffalo oocytes during cultured in TCM-199 supplemented with 2 μg/ml oestradiol (E(2)), 0.05 IU/ml recombinant human follicle stimulating hormone (rhFSH), 2IU/ml human chorionic gonadotrophin (hCG), and 0.12 IU/ml insulin (I). The cumulus oocytes complexes (COCs) were collected from 2-8mm follicles from local abattoir ovaries. Supplementation of medium with single hormones showed significant (P<0.0001) increase in mean diameter of COCs with rhFSH except E(2), hCG and insulin after 24 hours compared to the increase in the mean diameter of COCs matured in TCM-199 without any hormonal supplementation. With rhFSH even at 8th hour, significant increase (P<0.001) in cumulus expansion was observed. In combination of hormones the significant (P<0.0001) cumulus expansion was achieved in E(2)+rhFSH treatment group. The non significant (P>0.05) cumulus expansion was observed in treatment groups viz. E(2)+hCG, E(2)+Insulin, rhFSH+hCG, rhFSH+Insulin, hCG+Insulin, E(2)+rhFSH+hCG and E(2)+rhFSH+hCG+Insulin after 24 hours. In conclusion, supplementation of rhFSH alone and in combination with E(2)in TCM-199 has highly significant effect on cumulus expansion.

  9. Effect of Acrylamide on Oocyte Nuclear Maturation and Cumulus Cells Apoptosis in Mouse In Vitro.

    PubMed

    Liu, Shuzhen; Jiang, Ligang; Zhong, Tao; Kong, Shuhui; Zheng, Rongbin; Kong, Fengyun; Zhang, Cong; Zhang, Lei; An, Liguo

    2015-01-01

    Acrylamide (ACR) is a chemical compound with severe neurotoxicity, genotoxicity, carcinogenicity and reproductive toxicity. Recent studies showed that ACR impairs the function of reproductive organs, e.g., epididymis and testes. In vitro maturation of mouse oocyte is a sensitive assay to identify potential chemical hazard to female fertility. The aim of this study was to evaluate the adverse effects of ACR on the nuclear maturation and cumulus cells apoptosis of mouse oocytes in vitro. Cumulus-oocyte complexes were incubated in a maturation medium containing 0, 5, 10 and 20 μM of ACR. Chromosome alignment and spindle morphology of oocytes was determined by immunofluorescence and confocal microscopy. Our results showed that oocytes exposed to different doses of ACR in vitro were associated with a significant decrease of oocyte maturation, significant increase of chromosome misalignment rate, occurrence of abnormal spindle configurations, and the inhibition of oocyte parthenogenetic activation. Furthermore, apoptosis of cumulus cells was determined by TUNEL and CASPASE-3 assay. Results showed that apoptosis in cumulus cells was enhanced and the expression of CASPASE-3 was increased after cumulus-oocyte complexes were exposed to ACR. Therefore, ACR may affect the nuclear maturation of oocytes via the apoptosis of cumulus cells in vitro.

  10. Effects of Trichostatin A on Cumulus Expansion during Mouse Oocyte Maturation.

    PubMed

    Du, Ming; Fu, Xiangwei; Zhou, Yanhua; Zhu, Shien

    2013-11-01

    This study was conducted to investigate the effects of Trichostatin A (TSA) on cumulus expansion during mouse oocyte maturation. TSA treatment inhibited cumulus expansion and significantly reduced the cumulus expansion index (CEI) (p<0.05). To determine the underlying mechanism, the expression levels of several key factors that play crucial roles in cumulus expansion including components of extracellular matrix (ECM) (Has2, Ptgs2, Ptx3, and Tnfaip6) and Growth differentiation factor 9 (GDF9) were measured in control and TSA treated samples by real-time PCR. The effect of TSA on ERK phosphorylation (p-ERK1/2) in cumulus cells and GDF9 protein level in fully grown oocytes (FGOs) were detected by Western blotting. The expression levels of the ECM genes were significantly decreased (p<0.05) by TSA treatment while GDF9 expression did not response to TSA (p>0.05). TSA treatment blocked the activation of ERK1/2 (p<0.05) and had no significant effect on GDF9 protein expression (p>0.05). Collectively, these results suggested that TSA treatment altered ECM gene expression and blocked ERK1/2 activation to inhibit cumulus expansion in the mouse.

  11. Shallow Cumulus Sensitivity to Aerosol within a Fixed Meteorology Framework (Invited)

    NASA Astrophysics Data System (ADS)

    Seigel, R. B.

    2013-12-01

    Shallow cumulus clouds are critically important to the global energy budget and the general circulation of the earth. These clouds occupy up to a quarter of the global cloud fraction and they play a crucial role in mixing boundary layer properties with the free troposphere. As such, shallow cumulus clouds have a large effect on the vertical thermodynamic structure of the lower atmosphere, which then directly impacts larger scale circulations. Therefore, changes to the vertical mixing rates of cumulus clouds by forcing mechanisms such as aerosol loading can result in significant consequences for the general circulation of the Earth. This study aims to isolate changes in cumulus vertical mixing by a single forcing mechanism - aerosol loading. In order to isolate aerosol induced changes in cumulus mixing that are solely due to microphysical-dynamical interactions and not from mean-state thermodynamic instability changes caused by aerosol-cloud-precipitation feedbacks, this study uses a new approach of forcing shallow cumulus clouds in large eddy simulations (LESs). Nine (9) LESs with systematic variations in aerosol concentration and model domain size are initialized with the well-studied trade cumulus regime of the Barbados Oceanographic and Meteorological Experiment (BOMEX). However, rather than using the standard BOMEX forcing functions for each of the nine (9) simulations, which can result in different mean thermodynamic states when variations in aerosol concentration are imposed, the horizontal mean states of the following four (4) model prognosed variables are held fixed: liquid potential temperature (θl), total water (qt), zonal wind (u) and meridional wind (v). This guarantees that all variations of the cloud populations and their role in mixing are strictly the result of local microphysical-dynamical changes that result from changes in aerosol concentrations and not from changes to bulk conditional instability. Results from the nine (9) simulations show

  12. Involvement of the serine protease inhibitor, SERPINE2, and the urokinase plasminogen activator in cumulus expansion and oocyte maturation.

    PubMed

    Lu, Chung-Hao; Lee, Robert Kuo-Kuang; Hwu, Yuh-Ming; Lin, Ming-Huei; Yeh, Ling-Yu; Chen, Ying-Jie; Lin, Shau-Ping; Li, Sheng-Hsiang

    2013-01-01

    The serpin peptidase inhibitor, clade E, member 2 (SERPINE2) inhibits urokinase-type plasminogen activator (PLAU) and tissue-type plasminogen activator. Higher SERPINE2 expression levels were detected in cumulus cells of human immature oocytes than in those of mature oocytes. The objective of this study was to evaluate whether high SERPINE2 levels in cumulus cells are associated with oocyte immaturity. Using the mouse cumulus-oocyte complex as an experimental model, the effects of elimination and overexpression of SERPINE2 in cumulus cells on cumulus expansion and oocyte maturation were assayed by in vitro maturation. Serpine2 and PLAU transcripts were the most highly expressed serpins and plasminogen activators, respectively. Their expression was coordinately regulated in cumulus cells during gonadotropin-induced oocyte maturation. Silencing of Serpine2 expression using small interfering RNAs or blockage of SERPINE2 protein using a specific antibody had no effect on oocyte maturation. However, overexpression of Serpine2 or exogenous supplementation with high levels of SERPINE2 impaired cumulus expansion and oocyte maturation, probably by decreasing hyaluronan synthase 2 (Has2) and versican (Vcan) mRNA expression. Amiloride, a specific PLAU inhibitor, also suppressed these processes. PLAU supplementation of the oocyte in vitro maturation medium caused earlier and more extensive expansion of cumulus cells and oocyte maturation that may be mediated by increased Has2 mRNA expression. However, these effects were neutralized by coincubation with SERPINE2 or amiloride and PLAU. In conclusion, SERPINE2 and PLAU are involved in cumulus expansion and oocyte maturation. High SERPINE2 levels impair these processes, probably by decreasing cumulus matrix gene expression as well as reducing cumulus hyaluronan contents and inhibiting PLAU activity. These findings may explain why cumulus cells surrounding immature human oocytes express high SERPINE2 levels.

  13. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    DOE PAGES

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; ...

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasingmore » scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.« less

  14. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    SciTech Connect

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasing scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.

  15. Overview of the Cumulus Humilis Aerosol Processing Study

    SciTech Connect

    Berg, Larry K.; Berkowitz, Carl M.; Ogren, John A.; Hostetler, Chris A.; Ferrare, Richard; Dubey, Manvendra K.; Andrews, Elizabeth; Coulter, Richard L.; Hair, John; Hubbe, John M.; Lee, Yin-Nan; Mazzoleni, Claudio; Olfert, Jason N.; Springston, Stephen R.

    2009-11-30

    The primary goal of the Cumulus Humilis Aerosol Processing Study (CHAPS) was to characterize and contrast freshly emitted aerosols below, above, and within fields of cumuli, and to study changes to the cloud microphysical structure within these same cloud fields. The CHAPS is one of very few studies that have had an Aerosol Mass Spectrometer (AMS) sampling downstream of a counter-flow virtual impactor (CVI) inlet on an aircraft, allowing the examination of the chemical composition of the nucleated aerosols within the cumuli. The results from the CHAPS will provide insights into changes in the aerosol chemical and optical properties as aerosols move through shallow cumuli downwind of a moderately sized city. Three instrument platforms were employed during the CHAPS, including the U.S. Department of Energy Gulfstream-1 aircraft, which was equipped for in situ sampling of aerosol optical and chemical properties; the NASA-Langley King Air B200, which carried the downward looking NASA Langley High Spectral Resolution Lidar (HSRL) to measure profiles of aerosol backscatter, extinction, and depolarization between the King Air and the surface; and a surface site equipped for continuous in situ measurements of aerosol properties, profiles of aerosol backscatter, and meteorological conditions including total sky cover and thermodynamic profiles of the atmosphere. In spite of record precipitation over central Oklahoma, a total of eight research flights were made by the G-1, and eighteen by the B200, including special satellite verification flights timed to coincide with NASA satellite A-Train overpasses.

  16. Rainfall results, 1970-1975: Florida area cumulus experiment.

    PubMed

    Woodley, W L; Simpson, J; Biondini, R; Berkeley, J

    1977-02-25

    The latest rainfall results of the Florida Area Cumulus Experiment (FACE) are discussed after a review of the background, design, and early results of this experiment. Analysis without the benefit of data stratification and appropriate covariates of the 48 random experimentation days obtained through 1975 provided no evidence that dynamic seeding appreciably altered the rainfall over the fixed target area (1.3 x 10(4) square kilometers). Partitioning of the experimentation days according to whether the convective echoes moved across the Florida peninsula or developed in situ was more informative. Use of this echo motion covariate with five meaningful predictor models of natural rainfall in a stepwise regression program produced persuasive evidence for an effect of seeding in both echo motion categories. For days with moving echoes, there is evidence for a positive, statistically significant treatment effect on the rainfall from the subject clouds (the floating target) and in the overall target area. The results for days with stationary echoes, although considerably more tentative, suggest that seeding produces more rainfall in the floating target but with no net change of the precipitation in the overall target area. The ramifications of this result and a possible explanation are discussed. Corroborative statistical analyses and discussion are presented, including a discussion of the physical bases and history of the echo motion covariate and the meteorological predictors, analysis that is supportive of the rain-gage-adjusted radar measurements of precipitation in FACE and results of relevant cloud physics measurements in Florida.

  17. Does convective aggregation need to be represented in cumulus parameterizations?

    NASA Astrophysics Data System (ADS)

    Tobin, Isabelle; Bony, Sandrine; Holloway, Chris E.; Grandpeix, Jean-Yves; Sèze, Geneviève; Coppin, David; Woolnough, Steve J.; Roca, Rémy

    2013-12-01

    Tropical deep convection exhibits a variety of levels of aggregation over a wide range of scales. Based on a multisatellite analysis, the present study shows at mesoscale that different levels of aggregation are statistically associated with differing large-scale atmospheric states, despite similar convective intensity and large-scale forcings. The more aggregated the convection, the dryer and less cloudy the atmosphere, the stronger the outgoing longwave radiation, and the lower the planetary albedo. This suggests that mesoscale convective aggregation has the potential to affect couplings between moisture and convection and between convection, radiation, and large-scale ascent. In so doing, aggregation may play a role in phenomena such as "hot spots" or the Madden-Julian Oscillation. These findings support the need for the representation of mesoscale organization in cumulus parameterizations; most parameterizations used in current climate models lack any such representation. The ability of a cloud system-resolving model to reproduce observed relationships suggests that such models may be useful to guide attempts at parameterizations of convective aggregation.

  18. Aerosol-induced mechanisms for cumulus congestus growth

    NASA Astrophysics Data System (ADS)

    Sheffield, Amanda M.; Saleeby, Stephen M.; Heever, Susan C.

    2015-09-01

    Tropical convection has been observed to contain three cloud modes, the middle of which is cumulus congestus clouds. Congestus clouds act to moisten the tropical atmosphere, may be mixed-phase, and on occasion surpass the freezing level inversion from where they may develop into deeper convection. This study investigates the impacts of enhanced aerosol concentrations on the growth of congestus clouds produced in idealized cloud-resolving model simulations run under a state of radiative convective equilibrium (RCE). High-resolution, long-duration simulations were completed using the Regional Atmospheric Modeling System (RAMS). Aerosol concentrations between 2 and 4 km above ground level were varied from clean to polluted conditions in order to represent the advection of Saharan dust over the Atlantic Ocean. The congestus populations within each aerosol simulation are statistically analyzed using 10 days of model output after the simulation reaches RCE. Results indicate that congestus in more polluted conditions produce greater amounts of cloud water and ice mass, enhanced updraft strengths, and an increase in the number of congestus cloud tops that extend above the freezing level. Enhanced vapor depositional growth on the populations of more numerous, smaller cloud droplets in the polluted conditions, and the subsequent increase in latent heat release in the warm phase regions of the cloud, is found to be important factors in convective invigoration of these cloud systems. Aerosol feedbacks associated with cold pools and condensate loading also influence the updraft strength and act in opposition to the warm phase invigoration processes.

  19. Entrainment and detrainment in a simple cumulus cloud model

    NASA Technical Reports Server (NTRS)

    Randall, D. A.; Huffman, G. J.

    1982-01-01

    A cumulus cloud model, analogous to the mixed-layer models of the planetary boundary layer and the upper ocean, is developed using a single, unitary entrainment process in which the motion of the cloud boundary relative to the mean flow is permitted, produced, and controlled by turbulent processes. An alternate theory to the mixing-length theory of Asai and Kasahara (1967) is proposed which completely removes the strong scale-dependence of the Asai-Kasahara model. The model reintroduces scale-dependence by introducing including the pe5turbation pressure term of the equation of vertical motion. It is shown that the model predicts deeper clouds than the Asai-Kasahara model for a given sounding, due to the entrainment assumption and the effects of the perturbation pressure. Lateral entrainment dominates cloud-top entrainment, although finite-difference errors increase the cloud-top entrainment rate from zero to a positive value in actual situations. The fractional entrainment rate for updrafts is determined to vary only slightly with height and to decrease only slowly as the cloud radius increases, while the fractional detrainment rate for updrafts increases with height.

  20. Transportation Electrification Education Partnership for Green Jobs and Sustainable Mobility

    SciTech Connect

    Peng, Huei; Mi, Chris; Gover, James

    2013-06-28

    This collaborative educational project between the University of Michigan—Ann Arbor, University of Michigan—Dearborn and the Kettering University successfully executed almost all the elements we proposed to do. In the original proposal, we proposed to develop four graduate courses, six undergraduate courses, four professional short courses, a K-12 electric vehicle education kit, a Saturday morning seminar series, and a set of consumer education material to support the advancement of transportation electrification. The first four deliverables were all successfully developed and offered. When we held the kick-off meeting in NETL in Morgantown back in early 2010 with all the ten ARRA education teams, however, it quickly became clear that among the ten ARRA education grantee teams, our proposed “consume education” activities are not better or with the potential to create bigger impact than some of activities proposed in other teams. For example, the Odyssey 2010 event held by the West Virginia University team had planned and successfully reached to more than 230,000 attendees, which is way more than what our proposed 100k event could ever reach. It was under the suggestion of Joseph Quaranta, the ARRA education Program Director at that time, that we should coordinate and eliminate redundancy. The resources should then be focused on activities that have less overlap. Therefore, the originally proposed activities: Saturday morning seminar series, and a set of consumer education material were dropped from our scope. We expanded the scope of our “education kit” activity to include some educational materials, mainly in the form of videos. The target audience also changed from general public to K-12 students. The majority of the project cost (~70%) goes toward the establishment of three undergraduate laboratories, which provides critically needed hands-on learning experience for next-generation green mobility engineers. We are very proud that the ARRA money

  1. Best practices for photovoltaic household electrification programs: Lessons from experiences in selected countries. World Bank Technical Paper No. 324

    SciTech Connect

    Cabraal, A.; Cosgrove-Davies, M.; Schaeffer, L.

    1996-09-01

    The report draws on case studies of recent experiences in the Dominican Republic, Indonesia, the Philippines, and Sri Lanka to the identify key ingredients of successful residential photovoltaic (PV) electrification programs and ways of overcoming financial and institutional barriers to the use of PV systems. The report concludes that PV systems are a viable complement to grid-based energy services delivery and that these systems have a cost-effective niche and market potential within the rural electrification framework.

  2. Assessing the Impacts of Rural Electrification in Sub-Saharan Africa: The Case of Ethiopia

    NASA Astrophysics Data System (ADS)

    Aragaw, Mekonnen Lulie

    This study links rural electrification and the transition to modern energy services with poverty reduction and rural development in Ethiopia. Benefits of rural electrification in reducing poverty and accelerating rural development in low-income developing countries have been insufficiently researched. This study analyses available empirical evidence at a local level and examines how electricity access translates into productive use beyond powering radios and lighting. A survey of 336 households was conducted in Northern Ethiopia on impacts of electrification on four rural towns with varying number of years of access to electricity. Evidence at household and community levels shows that access to electricity was followed by an increase in household connectivity rate, and slow transition to modern energy services based on level of household income and number of years of a household's connection to electricity services. The pace of transition to modern energy services was slow, and household energy poverty and dependence on biomass fuels continued in most rural towns, having little impact on improved environmental management practices. Improvement in rural livelihood, poverty reduction, and delivery of public services was highest for those with more years of access to electricity, and higher income households. The fact that impacts of RE depend on number of years of a household's electricity connection implies gradual improvements rather than immediate benefits after connection. In the short-term, households improved their quality of life through better lighting and reduced indoor-air pollution. In the medium and longer-term, households and communities diversified their income and received improved public services such as education, health, and potable water. Further benefits were wider off-farm and non-farm employment, increased rural markets, and improved environment for rural development. Very poor households benefited least, while those better-off utilized

  3. Shallow cumulus processes deduced from subcloud flux measurements and parameterization schemes

    SciTech Connect

    Oetles, Z.

    1993-01-01

    The purposes of this study are to improve understanding of shallow cumulus in the planetary boundary layer (PBL), to quantitatively measure their subcloud root processes, and to link those measurements to estimates of cloud layer processes. Subcloud aircraft turbulence data for three days from the 1986 HAPEX project in southwest France is extensively analyzed. Various parameterizations of cloud layer processes are used to estimate cumulus layer effects by employing the subcloud fluxes as boundary conditions. Case 1 (5/21/86) had active cumuli; over the forest they were deep and large in diameter, but clouds over farmland were shallow and small in diameter. Case 2 (5/9/86) has also weak active cumulus with a smaller vertical depth and case 3 (6/13/86) had only forced cumuli. Four methods of decomposition of turbulence data have been employed: by land surface-cumulus regime, by proximity to clouds and clear areas, by scale, and by turbulence process types. In the presence strong active cumuli from case 1, the turbulent fluxes and energy are intensified, due to the cloud [open quotes]root[close quotes] effects. The strong active cumuli are initiated by warm-moist thermals. Since cumulus layer flux measurements were not made during the HAPEX experiment, different parameterization schemes have been used to estimate cloud layer fluxes. The schemes are: the simple cumulus flux scheme, the Betts-Miller adjustment scheme, an eddy diffusion scheme, and a new eddy diffusion scheme with counter-gradient term which is developed as a part of this study. For the strong active cumulus regime from case 1, the liquid water potential temperature and total water fluxes obtained from different parameterization schemes yield very similar results. Unlike the other parameterization schemes, the new eddy diffusion scheme with a counter-gradient term yields upward buoyancy fluxes which are in a good agreement with earlier studies.

  4. Transcriptomic diversification of developing cumulus and mural granulosa cells in mouse ovarian follicles.

    PubMed

    Wigglesworth, Karen; Lee, Kyung-Bon; Emori, Chihiro; Sugiura, Koji; Eppig, John J

    2015-01-01

    Cumulus cells and mural granulosa cells (MGCs) have functionally distinct roles in antral follicles, and comparison of their transcriptomes at a global and systems level can propel future studies on mechanisms underlying their functional diversity. These cells were isolated from small and large antral follicles before and after stimulation of immature mice with gonadotropins, respectively. Both cell types underwent dramatic transcriptomic changes, and differences between them increased with follicular growth. Although cumulus cells of both stages of follicular development are competent to undergo expansion in vitro, they were otherwise remarkably dissimilar with transcriptomic changes quantitatively equivalent to those of MGCs. Gene ontology analysis revealed that cumulus cells of small follicles were enriched in transcripts generally associated with catalytic components of metabolic processes, while those from large follicles were involved in regulation of metabolism, cell differentiation, and adhesion. Contrast of cumulus cells versus MGCs revealed that cumulus cells were enriched in transcripts associated with metabolism and cell proliferation while MGCs were enriched for transcripts involved in cell signaling and differentiation. In vitro and in vivo models were used to test the hypothesis that higher levels of transcripts in cumulus cells versus MGCs is the result of stimulation by oocyte-derived paracrine factors (ODPFs). Surprisingly ∼48% of transcripts higher in cumulus cells than MGCs were not stimulated by ODPFs. Those stimulated by ODPFs were mainly associated with cell division, mRNA processing, or the catalytic pathways of metabolism, while those not stimulated by ODPFs were associated with regulatory processes such as signaling, transcription, phosphorylation, or the regulation of metabolism.

  5. Effects of mesoscale convective organization and vertical wind shear on the cumulus-environment interaction

    SciTech Connect

    Wu, Xiaoqing.

    1992-01-01

    This study is made to understand the thermodynamic and dynamic aspects of cumulus-environment interaction. Specifically, the author examines (1) the similarities and differences of cumulus-environment interactions in the tropical and midlatitude convective systems (2) the impact of the presence of mesoscale circulations on the interpretation of cumulus-environment interaction, and (3) the effects of vertical wind shear on the dynamic interaction of cumulus convection with the large-scale motion. Analysis of PRE-STORM and GATE data show larger moist convective instability, large-scale forcing and vertical wind shear in the mid-latitude MCCs and squall lines than in the tropical non-squall clusters. The interaction mechanism based on the cumulus-induced subsidence and detrainment is capable of explaining most of the observed heating and drying under widely different environment conditions. The Arakawa-Schubert (A-S) quasi-equilibrium assumption is valid. Both the cumulus and stratiform cloud effects are stronger in midlatitude convective systems than in tropical systems. The heat and moisture budget results using the fine resolution SESAME data show pronounced dipole patterns in the horizontal distributions of vertically integrated heat source and moisture sink. Further analysis shows that the dipole pattern is closely related to the horizontal fluxes of heat and moisture due to mesoscale circulations. The quasi-equilibrium assumption becomes more accurate for the data resolving mesoscale circulation. The inclusion of downdrafts is required to accurately predict the cumulus heating and drying. Significant differences are found in vertical transport of horizontal momentum between the MCC and squall line. A new cloud momentum model which includes the convective-scale horizontal pressure gradient force has been developed. The application of the new cloud momentum model shows that the new model can simulate both the upgradient and downgradient transport of cloud momentum.

  6. Molecular analysis of the cumulus matrix: insights from mice with O-glycan-deficient oocytes.

    PubMed

    Ploutarchou, Panayiota; Melo, Pedro; Day, Anthony J; Milner, Caroline M; Williams, Suzannah A

    2015-05-01

    During follicle development, oocytes secrete factors that influence the development of granulosa and cumulus cells (CCs). In response to oocyte and somatic cell signals, CCs produce extracellular matrix (ECM) molecules resulting in cumulus expansion, which is essential for ovulation, fertilisation, and is predictive of oocyte quality. The cumulus ECM is largely made up of hyaluronan (HA), TNF-stimulated gene-6 (TSG-6, also known as TNFAIP6), pentraxin-3 (PTX3), and the heavy chains (HCs) of serum-derived inter-α-inhibitor proteins. In contrast to other in vivo models where modified expansion impairs fertility, the cumulus mass of C1galt1 Mutants, which have oocyte-specific deletion of core 1-derived O-glycans, is modified without impairing fertility. In this report, we used C1galt1 Mutant (C1galt1(FF):ZP3Cre) and Control (C1galt1(FF)) mice to investigate how cumulus expansion is affected by oocyte-specific deletion of core 1-derived O-glycans without adversely affecting oocyte quality. Mutant cumulus-oocyte complexes (COCs) are smaller than Controls, with fewer CCs. Interestingly, the CCs in Mutant mice are functionally normal as each cell produced normal levels of the ECM molecules HA, TSG-6, and PTX3. However, HC levels were elevated in Mutant COCs. These data reveal that oocyte glycoproteins carrying core 1-derived O-glycans have a regulatory role in COC development. In addition, our study of Controls indicates that a functional COC can form provided all essential components are present above a minimum threshold level, and thus some variation in ECM composition does not adversely affect oocyte development, ovulation or fertilisation. These data have important implications for IVF and the use of cumulus expansion as a criterion for oocyte assessment.

  7. Fibroblast growth factor 10 markedly improves in vitro maturation of porcine cumulus-oocyte complexes.

    PubMed

    Son, Yeo-Jin; Lee, Seung-Eun; Hyun, Hyuk; Shin, Min-Young; Park, Yun-Gwi; Jeong, Sang-Gi; Kim, Eun-Young; Park, Se-Pill

    2017-01-01

    Growth factors synthesized by ovarian somatic cells affect cumulus cell expansion and oocyte maturation in vitro. Fibroblast growth factor 10 (FGF10), for example, is a known regulator of mammalian cumulus-oocyte complex maturation. In this study, we investigated the effects of 0, 5, 10, 50, and 100 ng/mL FGF10 (5F, 10F, 50F, and 100F, respectively) on in vitro cumulus cell expansion, oocyte maturation, and embryo development. The percentage of fully expanded cumulus cells at the oocyte's metaphase-II (MII) stage was significantly higher in the 10F-treated group than in the control. Transcript abundance of the cumulus cell expansion-related gene encoding hyaluronian synthase 2 (HAS2) in cumulus cells at oocyte germinal vesicle breakdown (GVBD) was significantly higher in the 10F- and 50F-treated groups compared to untreated controls, whereas the mRNA abundance of the protease cathepsin B (CTSB) at the oocyte MII stage was remarkably decreased in the 10F-treated group. The percentage of oocytes with normal spindles was greater in the 10F- and 50F-treated group at GVBD than in the other groups; the 5F-, 10F-, and 100F-treated groups were higher than the control; and the 50F-treated group was highest at MII. The abundance of GDF9 and BMP15 transcript at GVBD and BMP15 and CCNB1 transcripts at MII increased in the 10F-treated group. Cleavage rate, blastocyst formation rate, and total cell number were significantly higher in the 5F- to 50F-treated groups. These results demonstrate that FGF10 markedly improves cumulus cell expansion, oocyte maturation, and subsequent embryo development. Mol. Reprod. Dev. 84: 67-75, 2017. © 2016 Wiley Periodicals, Inc.

  8. Knockdown of TrkA in cumulus oocyte complexes (COCs) inhibits EGF-induced cumulus expansion by down-regulation of IL-6.

    PubMed

    Wang, Yong; Liang, Ning; Yao, Guidong; Tian, Hui; Zhai, Yiwen; Yin, Yimeng; Sun, Fei

    2014-02-15

    Tyrosine kinase receptor A (TrkA), the high-affinity receptor of nerve growth factor (NGF), is known to play key roles in ovarian follicular development, such as assembly of early follicles and follicular ovulation. However, little is known about the roles of TrkA in cumulus oocyte complex (COC) expansion. In this study, we found that TrkA was abundant in large antral follicles and knockdown of TrkA in COCs attenuated epidermal growth factor (EGF)-induced COC expansion and further decreased the ovulation rate. The effect of TrkA on COC expansion was not mediated through downstream EGF effectors, phosphorylation of extracellular regulated protein kinases 1/2 (ERK1/2) or drosophila mothers against decapentaplegic protein (SMAD), or through up-regulation of COC expansion-related transcripts such as prostaglandin-endoperoxide synthase 2 (Ptgs2), hyaluronan synthase 2 (Has2), TNF-induced protein 6 (Tnfaip6) or pentraxin 3 (Ptx3). However, pharmacological blockade of TrkA transducing activity (K252α) in COCs decreased the mRNA expression and protein secretion of interleukin-6 (IL-6), identified from mRNA microarray of K252α-treated COCs. Meanwhile, knockdown of IL-6 attenuated EGF-induced COC expansion. In addition, IL-6 rescued the inhibitory effect of K252α on EGF-induced cumulus expansion. Therefore, IL-6 may act as a new potential cumulus expansion-related transcript, which may be involved in the integration of TrkA and EGF signaling in affecting COC expansion. Here, we provide mechanistic insights into the roles of TrkA in EGF-induced cumulus expansion. Understanding potential cross-points between TrkA and EGF affecting cumulus expansion will help in the discovery of new therapeutic targets in ovulation-related diseases.

  9. Granulocyte-macrophage colony stimulating factor (GM-CSF) enhances cumulus cell expansion in bovine oocytes

    PubMed Central

    2013-01-01

    Background The objectives of the study were to characterize the expression of the α- and β-subunits of granulocyte-macrophage colony stimulating factor (GM-CSF) receptor in bovine cumulus cells and oocytes and to determine the effect of exogenous GM-CSF on cumulus cells expansion, oocyte maturation, IGF-2 transcript expression and subsequent competence for embryonic development. Methods Cumulus-oocyte complexes (COC) were obtained by aspirating follicles 3- to 8-mm in diameter with an 18 G needle connected to a vacuum pump at −50 mmHg. Samples of cumulus cells and oocytes were used to detect GM- CSF receptor by immunofluorescence. A dose–response experiment was performed to estimate the effect of GM-CSF on cumulus cell expansion and nuclear/cytoplasmic maturation. Also, the effect of GM-CSF on IGF-2 expression was evaluated in oocytes and cumulus cells after in vitro maturation by Q-PCR. Finally, a batch of COC was randomly assigned to in vitro maturation media consisting of: 1) synthetic oviductal fluid (SOF, n = 212); 2) synthetic oviductal fluid supplemented with 100 ng/ml of GM-CSF (SOF + GM-CSF, n = 224) or 3) tissue culture medium (TCM 199, n = 216) and then subsequently in vitro fertilized and cultured for 9 days. Results Immunoreactivity for both α and β GM-CSF receptors was localized in the cytoplasm of both cumulus cells and oocytes. Oocytes in vitro matured either with 10 or 100 ng/ml of GM-CSF presented a higher (P < 0.05) cumulus cells expansion than that of the control group (0 ng/ml of GM-CSF). GM-CSF did not affect the proportion of oocytes in metaphase II, cortical granules dispersion and IGF-2 expression. COC exposed to 100 ng/ml of GM-CSF during maturation did not display significant differences in terms of embryo cleavage rate (50.4% vs. 57.5%), blastocyst development at day 7 (31.9% vs. 28.7%) and at day 9 (17.4% vs. 17.9%) compared to untreated control (SOF alone, P = 0.2). Conclusions GM-CSF enhanced cumulus

  10. Granulocyte-macrophage colony stimulating factor (GM-CSF) enhances cumulus cell expansion in bovine oocytes.

    PubMed

    Peralta, Oscar A; Bucher, Danai; Fernandez, Ana; Berland, Marco; Strobel, Pablo; Ramirez, Alfredo; Ratto, Marcelo H; Concha, Ilona

    2013-06-24

    The objectives of the study were to characterize the expression of the α- and β-subunits of granulocyte-macrophage colony stimulating factor (GM-CSF) receptor in bovine cumulus cells and oocytes and to determine the effect of exogenous GM-CSF on cumulus cells expansion, oocyte maturation, IGF-2 transcript expression and subsequent competence for embryonic development. Cumulus-oocyte complexes (COC) were obtained by aspirating follicles 3- to 8-mm in diameter with an 18 G needle connected to a vacuum pump at -50 mmHg. Samples of cumulus cells and oocytes were used to detect GM- CSF receptor by immunofluorescence. A dose-response experiment was performed to estimate the effect of GM-CSF on cumulus cell expansion and nuclear/cytoplasmic maturation. Also, the effect of GM-CSF on IGF-2 expression was evaluated in oocytes and cumulus cells after in vitro maturation by Q-PCR. Finally, a batch of COC was randomly assigned to in vitro maturation media consisting of: 1) synthetic oviductal fluid (SOF, n = 212); 2) synthetic oviductal fluid supplemented with 100 ng/ml of GM-CSF (SOF + GM-CSF, n = 224) or 3) tissue culture medium (TCM 199, n = 216) and then subsequently in vitro fertilized and cultured for 9 days. Immunoreactivity for both α and β GM-CSF receptors was localized in the cytoplasm of both cumulus cells and oocytes. Oocytes in vitro matured either with 10 or 100 ng/ml of GM-CSF presented a higher (P < 0.05) cumulus cells expansion than that of the control group (0 ng/ml of GM-CSF). GM-CSF did not affect the proportion of oocytes in metaphase II, cortical granules dispersion and IGF-2 expression. COC exposed to 100 ng/ml of GM-CSF during maturation did not display significant differences in terms of embryo cleavage rate (50.4% vs. 57.5%), blastocyst development at day 7 (31.9% vs. 28.7%) and at day 9 (17.4% vs. 17.9%) compared to untreated control (SOF alone, P = 0.2). GM-CSF enhanced cumulus cell expansion of in vitro matured bovine

  11. Contact Electrification of Regolith Particles and Chloride Electrolysis: Synthesis of Perchlorates on Mars.

    PubMed

    Tennakone, K

    2016-10-01

    Contact electrification of chloride-impregnated martian regolith particles due to eolian agitation and moisture condensation on coalesced oppositely charged grains may lead to spontaneous electrolysis that generates hypochlorite, chlorite, chlorate, and perchlorate with a concomitant reduction of water to hydrogen. This process is not curtailed even if moisture condenses as ice because chloride ionizes on the surface of ice. Limitations dictated by potentials needed for electrolysis and breakdown electric fields enable estimation of the required regolith grain size. The estimated dimension turns out to be of the same order of magnitude as the expected median size of martian regolith, and a simple calculation yields the optimum rate of perchlorate production. Key Words: Mars oxidants-Perchlorate-Dust electrification-Electrolysis. Astrobiology 16, 811-816.

  12. List of materials acceptable for use on systems of REA electrification borrowers

    SciTech Connect

    Not Available

    1993-07-01

    The publication provides a convenient informational and updated reference list of the items of materials and equipment that have been determined by the Rural Electrification Administration (REA) to be acceptable for use on systems of REA Electrification Borrowers. The items include material and equipment for transmission and distribution facilities. Items not listed include office equipment, tools and work equipment, items of electric general plant and consumer owned wiring facilities. The listings apply only to new items of material and equipment and not to used items. In addition to items accepted on a general basis, this list also includes items accepted on a conditional basis. As one of the conditions in the listing of an item on a conditional basis, contractors are required to obtain the borrower's concurrence prior to its use.

  13. Photovoltaics for rural electrification in the People`s Republic of China

    SciTech Connect

    Wallace, W.L.; Tsuo, Y.S.

    1997-12-31

    Rapid growth in economic development, coupled with the absence of an electric grid in large areas of the rural countryside, has created a need for new energy sources both in urban centers and rural areas in China. The most critical need for rural electrification exists in northern and western China, where 80 million people had no access to grid electricity at the end of 1995. In February 1995, the US Department of Energy signed an Energy Efficiency and Renewable Energy Protocol Agreement with the Chinese State Science and Technology Commission in Beijing. Under this agreement, NREL is providing assistance to several central government and provincial government agencies in China to develop photovoltaic and photovoltaic hybrid applications for rural electrification.

  14. A study of utilization of photovoltaics for rural electrification in the Republic of Kiribati

    SciTech Connect

    Tani, Takayuki; Takahashi, Masahide; Semba, Hideo; Kashizaki, Kenji; Inoue, Tomoyuki; Wade, H.; Kamiyacho, Shuwa

    1994-12-31

    Kiribati consists of 33 islands in three main groups located in the mid-Pacific, astride both the equator and the International Date Line. The total land area, which amounts to only 725 square km. is distributed over approximately 3.5 million square km. In 1989, the Government of Kiribati had requested the Japanese government for technical assistance for a feasibility study of rural electrification by photovoltaics. According to this request, JICA had sent two preliminary study teams in 1989 and 1991. Then in 1992 JICA decided to implement this study. The paper describes results from the implementation phase which consisted of a preliminary verification of the desire of villages for electrification and the installation and operation of a pilot photovoltaic plant. Performance of the pilot plant is described and recommendations are made.

  15. Electrification of Shaken Granular Flows as a Model of Natural Storm Charging

    NASA Astrophysics Data System (ADS)

    Kara, O.; Nordsiek, F.; Lathrop, D. P.

    2015-12-01

    The charging of particulates in nature is widespread and observed in thunderstorms, volcanic ash clouds, thunder-snow, and dust storms. However the mechanism of charge separation at large (> 1km) scale is poorly understood. We perform simple laboratory experiments to better understand the collective phenomena involved in granular electrification. We confine granular particles in an oscillating cylindrical chamber which is enclosed and sealed by two conducting plates. The primary measurement is the voltage difference between the two plates. We find that collective effects occurring in the bulk of the material play a significant role in the electrification process. We extend that by addition of photodetection capabilities to the experimental chamber to detect electrical discharges between the particles and each other and the plates. We present measurements of electrical discharges in addition to the slower dynamics of voltage variation in the system.

  16. Impacts of Wind Farms on Cumulus Cloud Development in the Central Great Plains

    NASA Astrophysics Data System (ADS)

    Mahoney, L. C.; Wagner, T. J.; L'Ecuyer, T. S.; Kulie, M.

    2014-12-01

    Cumulus clouds have a net cooling effect on the surface radiative balance by reflecting more downwelling solar radiation than absorbing upwelling terrestrial radiation. As boundary layer cumuli form from buoyant, moist plumes ascending from the surface, their growth may be hindered by the turbulent deformation of the plume by wind farms. A natural laboratory to study the impact of wind farms on cumulus formation are the states of Iowa and Nebraska. Despite their prime location for wind resources and similar synoptic forcings, regulatory issues cause these two states to vary vastly in their wind power offerings. In 2013, Iowa ranked 3rd in the nation for total megawatts installed and generates over a quarter of its electricity from wind energy, more than any other state. In contrast, Nebraska has an order of magnitude fewer turbines installed, and less than five percent of the state's electrical load is wind-generated. This variance in wind power in close proximity makes Iowa and Nebraska a prime area for initial research. This study uses Geostationary Operational Environmental Satellite (GOES) visible satellite imagery from the summer of 2009 to 2013 to investigate cumulus development in these adjacent states, as the majority of large-scale wind farms in Iowa were completed by 2009. Image reflectances in Nebraska and Iowa are compared to determine the magnitude of cumulus growth. Preliminary analysis indicates a reduction in cumulus development near the existing wind farms; a synoptic investigation of these cases will be completed to determine causality.

  17. Impact of Prunus Cerasus on PGR and HAS2 in Cumulus Cells and Fertility Outcome

    PubMed Central

    Namvar Vansofla, Fatemeh; Roshangar, Leila; Montaseri, Azadeh; Soleimani Rad, Jafar

    2016-01-01

    Purpose: Cumulus cells have a critical role in normal oocyte development and fertilization. Prunus cerasus is an anthocyanin rich berry and performs strong antioxidant activity. The present study set to determine if Prunus cerasus can affect expression of HAS2 (hyaluronan synthase 2) and progesterone receptor in Cumulus cells and its consequences outcome of the in vitro fertilization. Methods: 60 female and 15 male adult mice were used for mating and IVF (in vitro fertilization). Prunus cerasus extraction was added to the diet of female mice for 30 days. Ovulation induction and oocytes collection were done as routine. The cumulus cells were dissected apart, and the expression of progesterone receptor and HAS2 was detected using RT-PCR (real-time polymerase chain reaction). Fertilization rate was evaluated by IVF. All data were analyzed using t-test. Results: Data was showed that expression of progesterone receptor and HAS2 in cumulus cells of mice that received prunus cerasus increased. Moreover, oocyte fertilization rate also increased significantly. Conclusion: Prunus cerasus as an antioxidant natural can become an important medication for improving oocyte quality and opening new opportunities for infertility treatment. It is concluded that Prunus cerasus consumption could improve fertility rate by increasing progesterone receptor and HAS2 activity in cumulus cells. PMID:27123419

  18. Expression and localization of urokinase-type plasminogen activator receptor in bovine cumulus-oocyte complexes.

    PubMed

    García, Daniela C; Miceli, Dora C; Rizo, Gabriela; García, Elina V; Valdecantos, Pablo A; Roldán-Olarte, Mariela

    2016-04-01

    Urokinase-type plasminogen activator (uPA) is a serine protease involved in extracellular matrix remodeling through plasmin generation. uPA usually binds to its receptor, uPAR, which is anchored to the plasma membrane through a glycosylphosphatidylinositol anchor. uPA/uPAR binding increases proteolytic activity in the neighborhood of the cells containing uPAR and activates intracellular signaling pathways involved in extracellular matrix remodeling, cell migration and proliferation. The aim of this work was to study the expression of uPA, uPAR and plasminogen activator inhibitor-1 (PAI-1) in immature and in vitro matured bovine cumulus-oocyte complexes (COCs). uPA is only expressed in the cumulus cells of immature and in vitro matured COCs, while uPAR and PAI-1 are expressed in both the cumulus cells and the immature and in vitro matured oocytes. In addition, uPAR protein was localized by confocal microscopy in the plasma membrane of oocytes and cumulus cells of immature COCs. Results from this research led us to hypothesize that the uPA/uPAR interaction could cause the local production of uPA-mediated plasmin over oocyte and cumulus cell surface; plasmin formation could also be regulated by PAI-1.

  19. Intercomparison and Evaluation of Cumulus Parameterizations under Summertime Midlatitude Continental Conditions

    SciTech Connect

    Xie, S.; Cederwall, R.T.; Yio, J.J.; Xu, K.M.

    2001-05-17

    Parameterization of cumulus convection in general circulation model (GCM) has been recognized as one of the most important and complex issues in the model physical parameterizations. In earlier studies, most cumulus parameterizations were developed and evaluated using data observed over tropical oceans, such as the GATE (the Global Atmospheric Research Program's Atlantic Tropical Experiment) data. This is partly due to inadequate field measurements in the midlatitudes. In this study, we compare and evaluate a total of eight types of the state-of-the-art cumulus parameterizations used in fifteen Single-Column Models (SCM) under the summertime midlatitude continental conditions using the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) summer 1997 Intensive Operational Period (IOP) data, which covers several continental convection events. The purpose is to systematically compare and evaluate the performance of these cumulus parameterizations under summertime midlatitude continental conditions. Through the study we hope to identify strengths and weaknesses of these cumulus parameterizations that will lead to further improvements. Here, we briefly present our most interesting results. A full description of this study can be seen in Xie et al. (2001).

  20. Triggering of boundary layer cumulus clouds over a heterogeneous surface

    SciTech Connect

    Schrieber, K.; Stull, R.; Zhang, Q.

    1995-04-01

    Complex multimodal joint frequency distributions of LCL height versus {theta}{sub v} in surface-layer air over a large heterogeneous surface area are modeled as the superposition of simpler mono-modal distributions. These simpler distributions, which apply to quasi-homogeneous subdomains, are approximated with bivariate distribution models. The shape of each of these modeled distributions depends on variations of the Bowen ratio and heat input forcings. These forcings are a function of the landscape, insolation, surface albedo, cloud-shading, soil moisture, and other factors that either are known as imposed boundary conditions or can be resolved or parameterized on the coarse grid scale of a global climate forecast model (GCM). This approach is motivated by the need to forecast subgrid-scale boundary-layer cumulus clouds in GCMs and in one-dimensional (single column) forecast models. The full distribution function, formed as a composite from the simpler models, can be combined with mean virtual temperature sounding information to forecast cloud onset time, cloud coverage, cloud base and heights, and cloud size distributions of an ensemble of subgrid clouds. Thus, land-use inventories or similar satellite-based observations of relative landscape amounts have the potential to be combined with distribution parameterizations such as those explored to forecast subgrid clouds. As a case study, we have analyzed aircraft data from the Hydrologic Atmospheric Pilot Experiment (HAPEX) field experiment in southwest France, which was designed to answer basic questions about GCM subgrid modeling within a horizontal grid area 100 km on a side. For this data set, we found that bivariate range-cut Gaussian or pq distribution models work equally well to approximate the simpler mono-modal distributions within quasi homogeneous subdomains.

  1. Analysis of Cumulus Solar Irradiance Reflectance (CSIR) Events

    NASA Technical Reports Server (NTRS)

    Laird, John L.; Harshvardham

    1996-01-01

    Clouds are extremely important with regard to the transfer of solar radiation at the earth's surface. This study investigates Cumulus Solar Irradiance Reflection (CSIR) using ground-based pyranometers. CSIR events are short-term increases in solar radiation observed at the surface as a result of reflection off the sides of convective clouds. When sun-cloud observer geometry is favorable, these occurrences produce characteristic spikes in the pyranometer traces and solar irradiance values may exceed expected clear-sky values. Ultraviolet CSIR events were investigated during the summer of 1995 using Yankee Environmental Systems UVA-1 and UVB-1 pyranometers. Observed data were compared to clear-sky curves which were generated using a third degree polynomial best-fit line technique. Periods during which the observed data exceeded this clear-sky curve were identified as CSIR events. The magnitude of a CSIR event was determined by two different quantitative calculations. The MAC (magnitude above clear-sky) is an absolute measure of the difference between the observed and clear-sky irradiances. Maximum MAC values of 3.4 Wm(exp -2) and 0.069 Wm(exp -2) were observed at the UV-A and UV-B wavelengths, respectively. The second calculation determined the percentage above clear-sky (PAC) which indicated the relative magnitude of a CSIR event. Maximum UV-A and UV-B PAC magnitudes of 10.1% and 7.8%, respectively, were observed during the study. Also of interest was the duration of the CSIR events which is a function of sun-cloud-sensor geometry and the speed of cloud propagation over the measuring site. In both the UV-A and UV-B wavelengths, significant CSIR durations of up to 30 minutes were observed.

  2. Analysis of cumulus solar irradiance reflectance (CSIR) events

    NASA Astrophysics Data System (ADS)

    Laird, John L.; Harshvardhan

    Clouds are extremely important with regard to the transfer of solar radiation at Earth's surface. This study investigates Cumulus Solar Irradiance Reflection (CSIR) using ground-based pyranometers. CSIR events are short-term increases in solar radiation observed at the surface as a result of reflection off the sides of convective clouds. When Sun-cloud observer geometry is favorable, these occurrences produce characteristic spikes in the pyranometer traces and solar irradiance values may exceed expected clear-sky values. Ultraviolet CSIR events were investigated during the summer of 1995 using UVA and UVB pyranometers. Observed data were compared to clear-sky curves which were generated using a third degree polynomial best-fit line technique. Periods during which the observed data exceeded this clear-sky curve were identified as CSIR events. The magnitude of a CSIR event was determined by two different quantitative calculations. The MAC (magnitude above clear-sky) is an absolute measure of the difference between the observed and clear-sky irradiances. Maximum MAC values of 3.4 Win -2 and 0.0169 Wm -2 were observed at the UV-A and UV-B wavelengths, respectively. The second calculation determined the percentage above clear-sky (PAC) which indicated the relative magnitude of a CSIR event. Maximum UV-A and UV-B PAC magnitudes of 10.1% and 7.8%, respectively, were observed during the study. Also of interest was the duration of the CSIR events which is a function of Sun-cloud-sensor geometry and the speed of cloud propagation over the measuring site. In both the UV-A and UV-B wavelengths, significant CSIR durations of up to 30 minutes were observed. C 1997 Elsevier Science B.V.

  3. Los Sabinos PV rural electrification project: Results after 30 months of operation

    SciTech Connect

    Huacuz, J.M.; Agredano, J.; Munguia, G.; Flores, R.

    1994-12-31

    Los Sabinos, a small rural community in the mountains of Mexico has been electrified by means of small distributed PV systems. The systems were designed and built using for the first time the Technical Specification for Photovoltaic Rural Electrification Systems originally developed at IIE. Since 1992 the systems have been monitored. In this paper, the results after two and a half years of operation are presented. The main problems found are pointed out and the lessons learned are discussed.

  4. The product is progress: rural electrification in Costa Rica. Project impact evaluation No. 22

    SciTech Connect

    Hoover, G.; Goddard, P.O.; Gomez, G.; Harrison, P.

    1981-10-01

    Because Costa Rica had abundant hydroelectric potential and a government which was strongly committed to equitable growth, a considerable return was reaped from a relatively small investment in rural electrification (RE). This report details this success and A.I.D.'s contribution (1965-69). Aiming to diversify agriculture, increase income, expand agroindustry, and develop replicable RE cooperatives (REC's), the project produced positive but not wholly anticipated results.

  5. Annihilating time and space: The electrification of the United States Army, 1875--1920

    NASA Astrophysics Data System (ADS)

    Brown, Shannon Allen

    2000-10-01

    The United States Army embraced electrical technology in the 1870s as part of a wider initiative to meet the challenge of the coastal defense mission. As commercial power storage, generation, and transmission technology improved and the army came to recognize the value of the energy source as a means and method of improving command and control, localized electrical networks were integrated into the active service of the military. New vulnerabilities emerged as the army became ever more reliant upon electric power, however, and electrification---the institutional adoption and adaptation of electrical technologies---emerged as a very expensive and contentious process guided by technical, political, and economic pressures, and influenced by conflicting personalities within the service. This study considers the institutional evolution of the U.S. Army before and during World War I with respect to the adoption and application of electrical technology. The changing relationships between the military and electrical manufacturing and utilities industries during the period 1875--1920 are also explored. Using a combination of military archival sources and published primary materials, this study traces the effects of electrification on the army. In the end, this study proves that electrification was, at first, a symptom of, and later, a partial solution to the army's struggle to modernize and centralize during the period under consideration. Electrification produced a set of conditions that encouraged a new maturity within the ranks of the army, in technical, doctrinal, and administrative terms. This growth eventually led to the development of new capabilities, new forms of military organization, new missions, and new approaches to warfare.

  6. Comparisons of air quality impacts of fleet electrification and increased use of biofuels

    NASA Astrophysics Data System (ADS)

    Alhajeri, Nawaf S.; McDonald-Buller, Elena C.; Allen, David T.

    2011-04-01

    The air quality impacts of the partial electrification of the transportation fleet and the use of biofuels (E85) were modeled for the Austin Metropolitan Statistical Area, based on a 2030 vision of regional development. Changes in ozone precursor emissions and predicted ozone, carbon monoxide and aldehyde concentrations were estimated for multiple electrification and biofuel scenarios. Maximum changes in hourly ozone concentration from the use of plug-in hybrid electric vehicles (PHEVs) for 17% of the vehicle miles traveled ranged from - 8.5 to 2.2 ppb, relative to a base case with no electrification and minimal biofuel use, depending on time of day and location. Differences in daily maximum 1 h ozone concentration ranged from - 2.3 to 0.004 ppb. Replacement of all gasoline fuels with E85 had a smaller effect than PHEVs on maximum daily ozone concentrations. Maximum ozone changes for this scenario ranged from - 2.1 to 2.8 ppb and the difference in daily maximum 1 h ozone concentrations ranged from - 1.53 to 0 ppb relative to the base case. The smaller improvements in maximum ozone concentrations associated with extensive (100%) use of biofuels, compared to a smaller (17%) penetration of PHEVs, suggests that higher levels of PHEV penetration may lead to even greater improvements; however, the higher penetration would require expansion of the electrical grid capacity. The air quality impacts of the PHEVs would then depend on the emissions associated with the added generation.

  7. Fifty mega watt peak (50 MWp) photovoltaic rural electrification in Indonesia

    SciTech Connect

    Dasuki, A.S.; Djamin, M.

    1994-12-31

    Indonesia is the world`s largest archipelago which comprises more than 17,500 islands. According to national census, the population is now approaching 190 million inhabitants where 60% of them are living in rural areas. Many rural areas have sparsely populated areas, therefore providing electrical energy through conventional approach needs intensive capital investment for distribution networks and power plant construction. Some of the goals of the long term national energy development as described in the Second Stage Long-Term (twenty-five year) Development Strategy are to optimize the use of nonexportable energy resources, to increase the share of renewable energy use, and to achieve 100% rural electrification at the end of Five Year Development Plan 7. In order to achieve this Indonesian long-term energy development for rural electrification, the attractive solution is to apply photovoltaic system especially Solar Home System. Therefore the Government of Indonesia via the Agency for Assessment and Application of Technology has launched a project which is called ``Fifty Mega Watt Peak (50 MWp) Photovoltaic Rural Electrification in Indonesia``. This project target is to electrified one million households in ten years. This paper discusses and elaborates current status of Solar Home System in Indonesia, project implementation and scope of the project.

  8. Railroad electrification in America's future: an assessment of prospects and impacts. Final report

    SciTech Connect

    White, R.K.; Yabroff, I.W.; Dickson, E.M.; Zink, R.A.; Gray, M.E.; Moon, A.E.

    1980-01-01

    Such considerations as the level of traffic, the relative financial health of individual railroads, the capacity of the associated supply and engineering/construction industries, and the logical connecting points at classifying yards, as well as the national interest value of creating a continuous system, continental in scope, were used to construct a scenario for railroad electrification that closely approximates how an electrification program might be implemented. For the economic reasons cited, much of the US railroad system would remain conventionally powered. This scenario provides for an electrified network involving 14 mainlines operated by 10 companies that could transport much of the nation's rail-borne freight. Five years of planning and engineering work would be required for each link before construction could begin. With 1000 miles or less of electrified route per year, 14 years would be needed to construct the 9000-mile network of our scenario. (The scenario constructed runs from 1980 to 1998.) The analysis was aided with the construction of the SRI Railroad Industry Model. Basically a model of industry operations and finances, the model produces income statements and balance sheets at yearly intervals. Railroad energy costs, railroad freight levels, maintenance costs, purchases and leases of rooling stock, electrification facility investments, future inflation, rate setting practices, annual depreciation, taxes, and profits were calculated.

  9. 182 MATURATION OF BOVINE CUMULUS-OOCYTE COMPLEXES WITH FOLLICLE FLUID VARYING IN ESTRADIOL CONTENT AFFECTS CUMULUS CELL EXPANSION WITHOUT AFFECTING SUBSEQUENT EMBRYO DEVELOPMENT IN VITRO.

    PubMed

    Harl, A W; Larimore, E L; Al Naib, A; Wooldridge, L K; Ealy, A D; Perry, G A; Rhoads, M L

    2016-01-01

    The objective of this work was to determine how characteristics of bovine follicle fluid (FF; especially oestradiol content) affect cumulus cell expansion and oocyte competence. In the first study, FF was collected from abattoir-derived ovaries and pooled separately for large follicles (≥10mm) and small follicles (≤3mm). A portion of the FF from each category was charcoal stripped. These 4 types of FF were then used as the primary ingredient (75% vol/vol) in oocyte maturation media. A separate control group lacking FF but containing BSA was included to monitor potential impacts of protein on outcomes (control; without FF). Some of the cumulus-oocyte complexes (COC; n=250) were matured in individual drops for analysis of cumulus expansion (photographed and measured at 0 and 21h of maturation). Other COC (n=770) were matured in groups of 12 to 25 in the previously described media, and then subjected to IVF procedures. Cleavage rates were recorded on Day 3, and blastocyst rates were recorded on Day 8 post-fertilization. Cumulus cell expansion was greatest when COC were matured in medium containing FF from large follicles, wherein it even exceeded the controls (P<0.02). Maturation in FF from small follicles resulted in cumulus expansion that was intermediate between large and control. Maturation in charcoal-stripped FF severely restricted cumulus cell expansion (P<0.05) compared with those matured in untreated FF. Despite the observed improvement in cumulus cell expansion, COC that had been matured in media containing FF were less likely to cleave (P<0.05) and also less likely to develop to the blastocyst stage (P<0.01) than those matured in control medium. Cleavage and blastocyst rates did not differ among any of the maturation media containing FF. In the second study, oestrous cycles of 9 crossbred cows were synchronized and FF samples were collected 36 to 42h after prostaglandin F2α injection. Samples from individual cows were categorized as having high

  10. Cumulus clouds - Interactions between laboratory experiments and observations as foundations for models

    NASA Technical Reports Server (NTRS)

    Simpson, J.

    1983-01-01

    Early Woods Hole cumulus observations conducted with the aid of an aircraft suggested that buoyancy dilution by entrainment was a major brake upon tropical cumulus growth. The mechanism by which entrainment occurred, however, was not well understood. Ludlam and Scorer (1953) postulated that buoyant bubbles were the building blocks of cumulus clouds and that it was aerodynamic drag which caused the tops to cease rising. The present investigation is concerned with laboratory experiments and analyses which have been conducted to clarify remaining questions. Attention is given to bubbles in water of uniform density, bubbles released into stably stratified fluids, bubbles released into a two-layer fluid, some observational questions, and buoyant plumes and thermals. The considered experiments provide some insight concerning the mechanism involved in the conversion of buoyancy into motion, taking into account a simpler fluid situation.

  11. Contributions to the implementation of the Arakawa-Schubert cumulus parameterization in the GLA GCM

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Chao, Winston C.; Walker, G. K.

    1991-01-01

    The roles of the Critical Cloud Work Function (CCWF) data set and the upper and lower bounds on entrainment by cumulus plumes in the Arakawa-Schubert cumulus parameterization (ASCP) in the GLA GCM (Geller et al., 1988) were investigated in two sets of experiments. It was found that the horizontal and vertical distribution of cumulus heating can be altered in ASCP by adjusting these parameters. These changes can have a strong influence on the vertical structure of condensation heating, water vapor distribution, temperature, and rainfall. The CCWF is an important limiting parameter that controls the onset of different cloud types; increasing the threshold values of CCWF for all clouds tends to concentrate the rainfall into a narrower ITCZ and affects the rainfall during the initial adjustment period.

  12. Effect of eicosapentaenoic acid on bovine cumulus-oocyte complex in vitro.

    PubMed

    Nikoloff, Noelia; Pascua, Ana M; Anchordoquy, Juan M; Anchordoquy, Juan P; Sirini, Matías A; Seoane, Analia; Furnus, Cecilia C

    2017-05-01

    The aim of the present study was to investigate the effects of eicosapentaenoic acid (EPA) supplementation during in vitro maturation (IVM) of bovine oocytes. The concentrations tested in all experiments were 1 nM, 1 μM, and 1 mM EPA. The effect of EPA was evaluated on cumulus-oocyte complexes (COC) by oocyte maturation (cumulus expansion area and oocyte nuclear maturation), genotoxicity [single cell gel electrophoresis (SCGE)], and cytotoxicity (apoptosis, viability, and MTT assays) end points. The maturation parameters were affected by exposure of COC to different EPA concentrations in the IVM medium. Cumulus expansion area increased in the presence of 1 nM EPA (P < 0.05) whereas addition of 1 nM EPA (P < 0.05) decreased cumulus expansion after 24 h of IVM. Moreover, the maturation rate significantly decreased when 1 mM of EPA was assayed (P < 0.001). EPA at 1 nM induced genotoxic and cytotoxic effects on bovine cumulus cells (CC) and primary DNA lesions (P < 0.001). A significant increase in the frequency of apoptotic (P < 0.01) and necrotic (P < 0.001) cells was observed after 24 h of treatment with 1 nM, 1 μM, and 1 mM EPA. Mitochondrial activity was altered with 1 mM EPA (P < 0.001). We inferred that optimal oocyte quality was partially dependent on the presence of adequate EPA concentrations; EPA could be beneficial to improve oocyte quality in the maturation process, because low concentration tested (1 nM EPA) improved cumulus expansion. © 2017 International Federation for Cell Biology.

  13. Effects of exosome-like vesicles on cumulus expansion in pigs in vitro

    PubMed Central

    MATSUNO, Yuta; ONUMA, Asuka; FUJIOKA, Yoshie A; YASUHARA, Kazuma; FUJII, Wataru; NAITO, Kunihiko; SUGIURA, Koji

    2017-01-01

    Cell-secreted vesicles, such as exosomes, have recently been recognized as mediators of cell communication. A recent study in cattle showed the involvement of exosome-like vesicles in the control of cumulus expansion, a prerequisite process for normal ovulation; however, whether this is the case in other mammalian species is not known. Therefore, this study aimed to examine the presence of exosome-like vesicles in ovarian follicles and their effects on cumulus expansion in vitro in pigs. The presence of exosome-like vesicles in porcine follicular fluid (pFF) was confirmed by transmission electron microscopic observation, the detection of marker proteins, and RNA profiles specific to exosomes. Fluorescently labeled exosome-like vesicles isolated from pFF were incorporated into both cumulus and mural granulosa cells in vitro. Exosome-like vesicles were not capable of inducing cumulus expansion to a degree comparable to that induced by follicle-stimulating hormone (FSH). Moreover, exosome-like vesicles had no significant effects on the expression levels of transcripts required for the normal expansion process (HAS2, TNFAIP6, and PTGS2). Interestingly, FSH-induced expression of HAS2 and TNFAIP6 mRNA, but not of PTGS2 mRNA, was significantly increased by the presence of exosome-like vesicles; however, the degree of FSH-induced expansion was not affected. In addition, porcine exosome-like vesicles had no significant effects on the expansion of mouse cumulus-oocyte complexes. Collectively, the present results suggest that exosome-like vesicles are present in pFF, but they are not efficient in inducing cumulus expansion in pigs. PMID:28163264

  14. Time course of the meiotic arrest in sheep cumulus-oocyte complexes treated with roscovitine.

    PubMed

    Crocomo, Letícia Ferrari; Marques Filho, Wolff Camargo; Ackermann, Camila Louise; Paschoal, Daniela Martins; Guastali, Midyan Daroz; Dias Maziero, Rosiára Rosária; Sudano, Mateus José; Landim-Alvarenga, Fernanda da Cruz; Bicudo, Sony Dimas

    2016-04-01

    Temporary meiosis arrest with cyclin-dependent kinases inhibitors has been proposed in order to improve the quality of in vitro matured oocytes. In sheep, however, this phenomenon has been rarely investigated. Therefore, the present study aimed to evaluate the effect of different incubation times with roscovitine on nuclear maturation and cumulus cell expansion of sheep cumulus-oocyte complexes (COCs). For this, COCs were cultured for 0, 6, 12 or 20 h in basic maturation medium (Control) containing 75 μM roscovitine (Rosco). After, they were in vitro matured (IVM) for 18 h in the presence of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). At the end of each treatment, cumulus cell expansion and nuclear maturation were assessed under a stereomicroscope and by Hoechst 33342 staining, respectively. In the Control and Rosco groups, the absence of cumulus cell expansion prevailed at 0, 6, 12 and 20 h. After IVM for 18 h, total cumulus cell expansion in the Rosco treatments was dependent on the exposure time to roscovitine. A significantly high percentage of oocytes treated with roscovitine for 6 h (87%), 12 h or 20 h (65%) were arrested at the germinal vesicle (GV) stage. In contrast, 23% GVBD, 54% metaphase I (MI) and 61% MII oocytes were observed in the Control groups at 6, 12 and 20 h, respectively. In all treatments, a significant percentage of oocytes reached MII after IVM for 18 h. Therefore, roscovitine reversibly arrested the meiosis of sheep oocytes during different culture times with the maximal efficiency of meiotic inhibition reached at 6 h. In addition, reversibility of its inhibitory action on cumulus cells was exposure-time dependent.

  15. The macroscopic entrainment processes of simulated cumulus ensemble. Part II: Testing the entraining-plume model

    SciTech Connect

    Lin, Chichung; Arakawa, Akio

    1997-04-15

    According to Part I of this paper, is seems that ignoring the contribution from descendent cloud air in a cloud model for cumulus parameterization (CMCP), such as the spectral cumulus ensemble model in the Arakawa-Schubert parameterization, is an acceptable simplification for tropical deep convection. Since each subensemble in the spectral cumulus ensemble model is formally analogous to an entraining plume, the latter is examined using the simulated data from a cloud-resolving model (CRM). The authors first follow the analysis procedure of Warner. With the data from a nonprecipitating experiment, the authors show that the entraining-plume model cannot simultaneously predict the mean liquid water profile and cloud top height of the clouds simulated by the CRM. However, the mean properties of active elements of clouds, which are characterized by strong updrafts, can be described by an entraining plume of similar top height. With data from a precipitating experiment, the authors examine the spectral cumulus ensemble model using the Paluch diagram. It is found that the spectral cumulus ensemble model appears adequate if different types of clouds in the spectrum are interpreted as subcloud elements with different entrainment characteristics. The resolved internal structure of clouds can thus be viewed as a manifestation of a cloud spectrum. To further investigate whether the fractional rate of entrainment is an appropriate parameter for characterizing cloud types in the spectral cumulus ensemble model, the authors stratify the simulated saturated updrafts (subcloud elements) into different types according to their eventual heights and calculate the cloud mass flux and mean moist static energy for each type. Entrainment characteristics are then inferred through the cloud mass flux and in-cloud moist static energy. It is found that different types of subcloud elements have distinguishable thermodynamic properties and entrainment characteristics. 16 refs., 8 figs.

  16. Semiprognostic test of the Arakawa-Schubert cumulus parameterization using simulated data

    SciTech Connect

    Kuan-Man Xu; Aki Arakawa )

    1992-12-15

    The Arakawa-Schubert (A-S) cumulus parameterization is evaluated by performing semiprognostic tests against data simulated by a cumulus ensemble model (CEM). The CEM is a two-dimensional cloud model for simulating the formation of an ensemble of cumulus clouds under prescribed large-scale conditions. Three simulations, two with vertical wind shear and one without, are performed with identical (time-varying) large-scale advective effects. Detailed comparisons were made between the results of simulation and parameterization. The results include comparisions of surface precipitation rate, apparent heat source, apparent moisture sink, updraft mass flux, and downdraft mass flux. Two different sets of tests were performed. One was the standard A-S parameterization with the cloud work function (CWF) quasi equilibrium, and the other allowed CWF nonequilibrium by accounting for the simulated time change of the CWF. The tests show that the A-S parameterization is valid despite mesoscale organization in cumulus convection. The assumption of CWF quasi equilibrium is more accurate for inputs averaged over smaller subdomain sizes that resolve some mesoscale processes. Errors due to the nondiagnostic aspect of cumulus convection are more significant for inputs averaged over larger subdomain sizes. Errors due to the inherent nondeterministic aspect of cumulus convection appear to be more significant for inputs averaged over smaller subdomain sizes. A modified A-S parameterization with a convective-scale downdraft formulation was also tested against the simulated data. The inclusion of downdrafts slightly improves the results of semiprognostic tests. The impact of downdrafts on the subcloud layer may depend significantly on the subdomain size. 20 refs., 16 figs.

  17. The cumulus cell layer protects the bovine maturing oocyte against fatty acid-induced lipotoxicity.

    PubMed

    Lolicato, Francesca; Brouwers, Jos F; de Lest, Chris H A van; Wubbolts, Richard; Aardema, Hilde; Priore, Paola; Roelen, Bernard A J; Helms, J Bernd; Gadella, Bart M

    2015-01-01

    Mobilization of fatty acids from adipose tissue during metabolic stress increases the amount of free fatty acids in blood and follicular fluid and is associated with impaired female fertility. In a previous report, we described the effects of the three predominant fatty acids in follicular fluid (saturated palmitate and stearate and unsaturated oleate) on oocyte maturation and quality. In the current study, the effects of elevated fatty acid levels on cumulus cells were investigated. In a dose-dependent manner, the three fatty acids induced lipid storage in cumulus cells accompanied by an enhanced immune labeling of perilipin-2, a marker for lipid droplets. Lipidomic analysis confirmed incorporation of the administered fatty acids into triglyceride, resulting in a 3- to 6-fold increase of triglyceride content. In addition, palmitate selectively induced ceramide formation, which has been implicated in apoptosis. Indeed, of the three fatty acids tested, palmitate induced reactive oxygen species formation, caspase 3 activation, and mitochondria deterioration, leading to degeneration of the cumulus cell layers. This effect could be mimicked by addition of the ceramide-C2 analog and could be inhibited by the ceramide synthase inhibitor fumonisin-B1. Interfering with the intactness of the cumulus cell layers, either by mechanical force or by palmitate treatment, resulted in enhanced uptake of lipids in the oocyte and increased radical formation. Our results show that cumulus cells act as a barrier, protecting oocytes from in vitro induced lipotoxic effects. We suggest that this protective function of the cumulus cell layers is important for the developmental competence of the oocyte. The relevance of our findings for assisted reproduction technologies is discussed.

  18. Effects of exosome-like vesicles on cumulus expansion in pigs in vitro.

    PubMed

    Matsuno, Yuta; Onuma, Asuka; Fujioka, Yoshie A; Yasuhara, Kazuma; Fujii, Wataru; Naito, Kunihiko; Sugiura, Koji

    2017-02-16

    Cell-secreted vesicles, such as exosomes, have recently been recognized as mediators of cell communication. A recent study in cattle showed the involvement of exosome-like vesicles in the control of cumulus expansion, a prerequisite process for normal ovulation; however, whether this is the case in other mammalian species is not known. Therefore, this study aimed to examine the presence of exosome-like vesicles in ovarian follicles and their effects on cumulus expansion in vitro in pigs. The presence of exosome-like vesicles in porcine follicular fluid (pFF) was confirmed by transmission electron microscopic observation, the detection of marker proteins, and RNA profiles specific to exosomes. Fluorescently labeled exosome-like vesicles isolated from pFF were incorporated into both cumulus and mural granulosa cells in vitro. Exosome-like vesicles were not capable of inducing cumulus expansion to a degree comparable to that induced by follicle-stimulating hormone (FSH). Moreover, exosome-like vesicles had no significant effects on the expression levels of transcripts required for the normal expansion process (HAS2, TNFAIP6, and PTGS2). Interestingly, FSH-induced expression of HAS2 and TNFAIP6 mRNA, but not of PTGS2 mRNA, was significantly increased by the presence of exosome-like vesicles; however, the degree of FSH-induced expansion was not affected. In addition, porcine exosome-like vesicles had no significant effects on the expansion of mouse cumulus-oocyte complexes. Collectively, the present results suggest that exosome-like vesicles are present in pFF, but they are not efficient in inducing cumulus expansion in pigs.

  19. An aircraft study of rapid precipitation development and electrification in a growing convective cloud

    NASA Astrophysics Data System (ADS)

    Willis, P. T.; Hallett, J.; Black, R. A.; Hendricks, W.

    The rapid initial precipitation growth and initial electrification of a convective cloud, growing as a new cell on the upshear side of a cloud system in Florida, is traced from radar data and aircraft penetrations at the -7°C to -10°C level. This study combines radar, microphysical and electrical measurements so that an examination of the interactions between the cloud dynamics, microphysics and electrification is possible. The first pass (-7°C) was characterized by a strong 23 m/s updraft, all liquid cloud water, no precipitation, and no significant electrification. In the 300 s between the two penetrations, precipitation developed very rapidly from < 15 dBZ to < 45 dBZ, and the vertical component of the electric field increased from below the measurement threshold to - 25 kv/m. The second penetration, which started at - 7°C and ended at - 10°C, was still exclusively updraft, but with lesser peak velocities and a more complex structure; i.e., no downdraft, but with relative minima in the updraft. The microphysics of the second pass displayed a segment of exclusively cloud liquid water (no precipitation size hydrometeors), a small segment of all liquid precipitation size hydrometeors, a small region of mixed hydrometeors and an extensive region of graupel hydrometeors, ranging in size from 100 μm to several mm. High cloud liquid water coexisted with the liquid and graupel hydrometeors in the strong updrafts. The electrification was observed to occur exclusively in the segments of the cloud pass where graupel were observed. Within this graupel region, where the graupel often coexisted with supercooled cloud liquid water, significant electric field occurred only at relative minima in the updraft. These relative velocity minima were also minima in the cloud liquid water content. The observed updraft velocities in these relative minima were close to balance velocities for the observed larger graupel hydrometeors. The strongest updrafts, where the formation and

  20. Supplementation with cumulus cell masses improves the in vitro meiotic competence of porcine cumulus-oocytes complexes derived from small follicles.

    PubMed

    Matsunaga, R; Funahashi, H

    2017-03-30

    The present study was conducted to examine the supplemented effect of cumulus cell masses (CCMs) derived from middle follicle (MF; 3-6 mm diameter) on the morphology and the meiotic or developmental competence of oocytes from small follicles (SF; 1-2 mm diameter). The number of cumulus cells surrounding oocytes just after collection was also lower in cumulus-oocyte complexes (COCs) from SF than MF. The ooplasmic diameter of oocytes was significantly smaller in SF-derived oocytes than MF-derived ones before and after in vitro maturation (IVM), whereas the diameter significantly increased during the culture. Co-culture of SF-derived COCs with MF-derived CCMs during IVM significantly improved the meiotic competence of the oocytes to the metaphase-II stage. Furthermore, the ooplasmic diameter of SF-derived COCs during IVM was increased to the similar size of MF-derived those in the presence of MF-derived CCMs. The abilities of oocytes to be penetrated, to form male pronuclear formation and to cleave or develop to the blastocyst stage were not affected by the co-culture with CCMs. Electrophoretic analysis of CCM secretions clearly showed the presence of more protein(s) approximately 27.6 kDa in the conditioned medium when supplemented with MF-derived CCMs. In conclusion, we demonstrate that supplementation with MF-derived CCMs improves the ooplasmic diameter and meiotic competence of SF-derived oocytes.

  1. NASA Earth Science Research and Applications Using UAVs

    NASA Technical Reports Server (NTRS)

    Guillory, Anthony R.

    2003-01-01

    The NASA Earth Science Enterprise sponsored the UAV Science Demonstration Project, which funded two projects: the Altus Cumulus Electrification Study (ACES) and the UAV Coffee Harvest Optimization experiment. These projects were intended to begin a process of integrating UAVs into the mainstream of NASA s airborne Earth Science Research and Applications programs. The Earth Science Enterprise is moving forward given the positive science results of these demonstration projects to incorporate more platforms with additional scientific utility into the program and to look toward a horizon where the current piloted aircraft may not be able to carry out the science objectives of a mission. Longer duration, extended range, slower aircraft speed, etc. all have scientific advantages in many of the disciplines within Earth Science. The challenge we now face are identifying those capabilities that exist and exploiting them while identifying the gaps. This challenge has two facets: the engineering aspects of redesigning or modifying sensors and a paradigm shift by the scientists.

  2. NASA Earth Science Research and Applications Using UAVs

    NASA Technical Reports Server (NTRS)

    Guillory, Anthony R.

    2003-01-01

    The NASA Earth Science Enterprise sponsored the UAV Science Demonstration Project, which funded two projects: the Altus Cumulus Electrification Study (ACES) and the UAV Coffee Harvest Optimization experiment. These projects were intended to begin a process of integrating UAVs into the mainstream of NASA s airborne Earth Science Research and Applications programs. The Earth Science Enterprise is moving forward given the positive science results of these demonstration projects to incorporate more platforms with additional scientific utility into the program and to look toward a horizon where the current piloted aircraft may not be able to carry out the science objectives of a mission. Longer duration, extended range, slower aircraft speed, etc. all have scientific advantages in many of the disciplines within Earth Science. The challenge we now face are identifying those capabilities that exist and exploiting them while identifying the gaps. This challenge has two facets: the engineering aspects of redesigning or modifying sensors and a paradigm shift by the scientists.

  3. Cumulus cloud formation over West Atlantic Ocean north of South America

    NASA Image and Video Library

    1962-10-03

    S62-06613 (3 Oct. 1962) --- Cumulus cloud formation over West Atlantic Ocean north of South American during the fourth orbit pass of the Mercury-Atlas 8 (MA-8) mission by astronaut Walter M. Schirra Jr. with a hand-held camera. Photo credit: NASA

  4. Effect of Acrylamide on Oocyte Nuclear Maturation and Cumulus Cells Apoptosis in Mouse In Vitro

    PubMed Central

    Liu, Shuzhen; Jiang, Ligang; Zhong, Tao; Kong, Shuhui; Zheng, Rongbin; Kong, Fengyun; Zhang, Cong; Zhang, Lei; An, Liguo

    2015-01-01

    Acrylamide (ACR) is a chemical compound with severe neurotoxicity, genotoxicity, carcinogenicity and reproductive toxicity. Recent studies showed that ACR impairs the function of reproductive organs, e.g., epididymis and testes. In vitro maturation of mouse oocyte is a sensitive assay to identify potential chemical hazard to female fertility. The aim of this study was to evaluate the adverse effects of ACR on the nuclear maturation and cumulus cells apoptosis of mouse oocytes in vitro. Cumulus–oocyte complexes were incubated in a maturation medium containing 0, 5, 10 and 20 μM of ACR. Chromosome alignment and spindle morphology of oocytes was determined by immunofluorescence and confocal microscopy. Our results showed that oocytes exposed to different doses of ACR in vitro were associated with a significant decrease of oocyte maturation, significant increase of chromosome misalignment rate, occurrence of abnormal spindle configurations, and the inhibition of oocyte parthenogenetic activation. Furthermore, apoptosis of cumulus cells was determined by TUNEL and CASPASE-3 assay. Results showed that apoptosis in cumulus cells was enhanced and the expression of CASPASE-3 was increased after cumulus–oocyte complexes were exposed to ACR. Therefore, ACR may affect the nuclear maturation of oocytes via the apoptosis of cumulus cells in vitro. PMID:26275143

  5. Effects of Mitochondrial Uncoupling Protein 2 Inhibition by Genipin in Human Cumulus Cells

    PubMed Central

    Ge, Hongshan; Zhang, Fan; Shan, Dan; Chen, Hua; Wang, Xiaona; Ling, Chao; Xi, HaiTao; Huang, Jianying; Zhu, ChunFang; Lv, Jeiqiang

    2015-01-01

    UCP2 plays a physiological role by regulating mitochondrial biogenesis, maintaining energy balance, ROS elimination, and regulating cellular autophagy in numerous tissues. But the exact roles of UCP2 in cumulus cells are still not clear. Genipin, a special UCP2 inhibitor, was added into the cultural medium to explore the roles of UCP2 in human cumulus cells. There were no significant differences in ATP and mitochondrial membrane potential levels in cumulus cells from UCP2 inhibiting groups as compared with the control. The levels of ROS and Mn-SOD were markedly elevated after UCP2 inhibited Genipin. However, the ratio of reduced GSH to GSSG significantly declined after treatment with Genipin. UCP2 inhibition by Genipin also resulted in obvious increase in the active caspase-3, which accompanied the decline of caspase-3 mRNA. The level of progesterone in culture medium declined obviously after Genipin treatment. But there was no significant difference in estradiol concentrations. This study indicated that UCP2 is expressed in human cumulus cells and plays important roles on mediate ROS production, apoptotic process, and steroidogenesis, suggesting UCP2 may be involved in regulation of follicle development and oocyte maturation and quality. PMID:26356408

  6. Bidirectional communication between cumulus cells and the oocyte: Old hands and new players?

    PubMed

    Russell, Darryl L; Gilchrist, Robert B; Brown, Hannah M; Thompson, Jeremy G

    2016-07-01

    Cumulus cell-oocyte communication is an essential feature of mammalian reproduction. Established mechanisms involve the bidirectional transfer of ions and small molecules through gap junctions that fundamentally regulate the process of oocyte maturation. Also, well established is the paracrine signaling from the oocyte to the cumulus, which regulates much of the flow of ions and molecules to the oocyte and orchestrates many of the associated local signaling events around ovulation, which is the key to establishing oocyte competence to sustain early embryo development. Less well-characterized and new potential players include exosomal transfer of noncoding RNAs from cumulus to oocytes and the recent observations of the presence of hemoglobin in oocytes and cumulus cells. The impact of these new communication pathways is either poorly defined or even unknown. Finally, signaling between the two cell types most likely continues after ovulation and even fertilization; however, this too is largely undefined but may play roles in substrate transport, sperm chemotaxis and "trapping", and potential signaling to the rest of the reproductive tract.

  7. Characteristics of small tropical cumulus clouds and their impact on the environment

    SciTech Connect

    Benner, T.C.; Curry, J.A.

    1998-11-01

    This study uses a number of data sets (Moderate Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator data, space shuttle photography, Radiation Measurement System data, aircraft data, and shipboard soundings) to investigate the characteristics of small tropical cumulus clouds and their impact on their environment. The goal is to uncover useful information with application to radiative transfer simulation and satellite remote sensing. In fields of small cumulus clouds, size distributions are found to decrease in number with increasing diameter according to a double power law relation, often with a clear break diameter. Fractal dimensions corresponding to the horizontal area and perimeter of the clouds are greater for the larger clouds than for the smaller clouds, with the same break diameter as the size distributions, meaning that the larger clouds have more ragged perimeters. These two results suggest a characteristic horizontal length scale dividing larger and smaller boundary layer cumuli. Spatial distributions show a clear tendency toward clustering. Smaller cumuli appear to grow upward more quickly with increasing horizontal size than do larger cumuli. Albedo is found to increase with greater cloud fraction and higher solar zenith angle. Even sparse fields of small cumulus cause significant shortwave forcing at the ocean surface. Simulation suggests that small cumulus may introduce significant errors into sea surface temperature retrievals and that such clouds can be difficult to remove with operational cloud-filtering schemes. Clouds smaller than about 1 km in diameter are not seen to precipitate. {copyright} 1998 American Geophysical Union

  8. Interaction of a cumulus cloud ensemble with the large-scale environment

    NASA Technical Reports Server (NTRS)

    Arakawa, A.; Schubert, W.

    1973-01-01

    Large-scale modification of the environment by cumulus clouds is discussed in terms of entrainment, detrainment, evaporation, and subsidence. Drying, warming, and condensation by vertical displacement of air are considered as well as budget equations for mass, static energy, water vapor, and liquid water.

  9. On the air motion in continental shallow cumulus clouds: large-eddy simulation versus radar observation

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Chandra, A.; Klein, S. A.

    2013-12-01

    Summertime observations for 13 years at Atmospheric Radiation Measurement Southern Great Plains (SGP) site are used to study air motion in non-precipitating fair-weather shallow cumulus clouds. A composite shallow cumulus case is constructed based on an ensemble of days with observed active shallow cumulus clouds. Large-scale forcing for this composite case is derived accordingly based on observation-constrained variational analysis and is used to drive the large-eddy simulation (LES), whose set-up is most suitable to make an apple-to-apple comparison with radar observation at the site. At the same time, a novel retrieval algorithm, which can remove the insects' contamination on radar reflectivity, is applied to millimeter cloud radar 10s observations to get vertical velocity of air motion in the shallow cumulus cloud ensembles. We then focus on the behavior of cloudy profiles with liquid water path greater than 80 g/m^2. This is done because we believe this portion of cloud makes a major contribution to the total mass flux and by so doing, the uncertainty is minimized in the comparison between observation and LES results. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-641597

  10. The power of light: socio-economic and environmental implications of a rural electrification program in Brazil

    NASA Astrophysics Data System (ADS)

    Borges da Silveira Bezerra, Paula; Ludovique Callegari, Camila; Ribas, Aline; Lucena, André F. P.; Portugal-Pereira, Joana; Koberle, Alexandre; Szklo, Alexandre; Schaeffer, Roberto

    2017-09-01

    Universal access to electricity is deemed critical for improving living standards and indispensable for eradicating poverty and achieving sustainable development. In 2003, the ‘Luz para Todos’ (LpT—Light for All) program was launched aiming to universalize access to electricity in Brazil. The program focused on rural and isolated areas, also targeting to bring development to those regions along with electrification. This paper evaluates the results of the LpT program in improving socio-economic development in the poorest regions of Brazil. After an initial qualitative analysis, an empirical quantitative assessment of the influence of increased electrification rates on the components of the Human Development Index (HDI) is performed. The empirical results of this study showed that electrification had a positive influence on all dimensions of the HDI, with the education component having the strongest effect. Although complementary policies were needed to achieve this, results show that electricity access is a major requirement to improve quality of life.

  11. Intercomparison and Evaluation of Cumulus Parameterizations under Summertime Midlatitude Continental Conditions

    SciTech Connect

    Xie, S; Cederwall, R T; Yio, J; Xu, K-M

    2001-05-17

    Parameterization of cumulus convection in general circulation model (GCM) has been recognized as one of the most important and complex issues in the model physical parameterizations. In earlier studies, most cumulus parameterizations were developed and evaluated using data observed over tropical oceans, such as the GATE (the Global Atmospheric Research Program's Atlantic Tropical Experiment) data. This is partly due to inadequate field measurements in the midlatitudes. In this study, we compare and evaluate a total of eight types of the state-of-the-art cumulus parameterizations used in fifteen Single-Column Models (SCM) under the summertime midlatitude continental conditions using the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) summer 1997 Intensive Operational Period (IOP) data, which covers several continental convection events. The purpose is to systematically compare and evaluate the performance of these cumulus parameterizations under summertime midlatitude continental conditions. Through the study we hope to identify strengths and weaknesses of these cumulus parameterizations that will lead to further improvements. Here, we briefly present our most interesting results. A full description of this study can be seen in Xie et al. (2001). The authors conclude that: (1) The SCM simulation errors are closely related to problems with model cumulus parameterizations. The schemes with triggering based on CAPE generally produce more active cumulus convection than the schemes with triggering based on local parcel buoyancy over land surface at midlatitudes since CAPE is usually large and is mainly determined by the strong solar diurnal heating there. The use of positive CAPE to trigger model convection can lead to an overestimation of convection during the daytime. This results in warmer/drier atmospheres in the former and cooler/more moist atmospheres in the latter. (2) A non-penetrative convection scheme can underestimate the depth of

  12. Assessing the Future Vehicle Fleet Electrification: The Impacts on Regional and Urban Air Quality.

    PubMed

    Ke, Wenwei; Zhang, Shaojun; Wu, Ye; Zhao, Bin; Wang, Shuxiao; Hao, Jiming

    2017-01-17

    There have been significant advancements in electric vehicles (EVs) in recent years. However, the different changing patterns in emissions at upstream and on-road stages and complex atmospheric chemistry of pollutants lead to uncertainty in the air quality benefits from fleet electrification. This study considers the Yangtze River Delta (YRD) region in China to investigate whether EVs can improve future air quality. The Community Multiscale Air Quality model enhanced by the two-dimensional volatility basis set module is applied to simulate the temporally, spatially, and chemically resolved changes in PM2.5 concentrations and the changes of other pollutants from fleet electrification. A probable scenario (Scenario EV1) with 20% of private light-duty passenger vehicles and 80% of commercial passenger vehicles (e.g., taxis and buses) electrified can reduce average PM2.5 concentrations by 0.4 to 1.1 μg m(-3) during four representative months for all urban areas of YRD in 2030. The seasonal distinctions of the air quality impacts with respect to concentration reductions in key aerosol components are also identified. For example, the PM2.5 reduction in January is mainly attributed to the nitrate reduction, whereas the secondary organic aerosol reduction is another essential contributor in August. EVs can also effectively assist in mitigating NO2 concentrations, which would gain greater reductions for traffic-dense urban areas (e.g., Shanghai). This paper reveals that the fleet electrification in the YRD region could generally play a positive role in improving regional and urban air quality.

  13. Initial electrification to the first lightning flash in New Mexico thunderstorms

    NASA Astrophysics Data System (ADS)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Krehbiel, Paul R.

    2015-11-01

    The initial electrification of three New Mexico thunderstorms is examined using in situ and remote measurements. The earliest deflection of electric field (E) measured at the surface was 5-8.6 min before the first flash and coincident with the development of substantial radar reflectivity (40 dBZ) above -5°C. Rapid growth of surface E (>5 V/m/s) started 2.4-3.1 min before the first flash, when 40 dBZ reflectivities reached above the -15°C level. In two cases with clear surface E records, radar reflectivity indicators (40 dBZ echo through -10°C and echo top through -15°C) would yield longer warning times before the first flash than the E record. The first flash in each storm initiated at altitudes between 7.4 and 8.8 km; hence, the temperatures where the largest (negative) E for normal intracloud lightning initiation had developed during the initial electrification were -10°C to -20°C. Negative and positive charge regions associated with the first flash in each cell were centered at -8°C to -16°C (6.9-8.0 km) and -20°C to -24°C (9.0-9.2 km), respectively. In two cases, balloon data indicate the only substantial charge regions present before the first flash were those involved in the flash. Another case shows an initial period of opposite polarity E deflection at the surface coincident with substantial low-level positive charge within the cloud, although this charge was not involved in the first 8 min (first 17 flashes) of lightning activity. The findings support the notion that the initial electrification resulted from charging via the noninductive ice-ice collisional mechanism.

  14. Effect of oil overlay on inhibition potential of roscovitine in sheep cumulus-oocyte complexes.

    PubMed

    Crocomo, L F; Marques Filho, W C; Ulian, C M V; Branchini, N S; Silva, D T; Ackermann, C L; Landim-Alvarenga, F C; Bicudo, S D

    2015-06-01

    Inhibitors of cyclin-dependent kinases, as roscovitine, have been used to prevent the spontaneous resumption of meiosis in vitro and to improve the oocyte developmental competence. In this study, the interference of oil overlay on the reversible arrest capacity of roscovitine in sheep oocytes as well as its effects on cumulus expansion was evaluated. For this, cumulus-oocyte complexes (COCs) were cultured for 20 h in TCM 199 with 10% foetal bovine serum (Control) containing 75 μm roscovitine (Rosco). Subsequently, they were in vitro matured (IVM) for further 18 h in inhibitor-free medium with LH and FSH. The culture was performed in Petri dishes under mineral oil (+) or in 96 well plates without oil overlay (-) at 38.5°C and 5% CO2 . At 20 and 38 h, the cumulus expansion and nuclear maturation were evaluated under stereomicroscope and by Hoechst 33342 staining, respectively. No group presented cumulus expansion at 20 h. After additional culture with gonadotrophins, a significant rate of COCs from both Control groups (+/-) exhibited total expansion while in both Rosco groups (+/-) the partial expansion prevailed. Among the oocytes treated with roscovitine, 65.2% were kept at GV in the absence of oil overlay while 40.6% of them reached MII under oil cover (p < 0.05). This meiotic arrest was reversible, and proper meiosis progression also occurred in the Control groups (+/-). So, the culture system without oil overlay improved the meiotic inhibition promoted by roscovitine without affecting the cumulus expansion rate or the subsequent meiosis progression. © 2015 Blackwell Verlag GmbH.

  15. Intercomparison and Evaluation of Cumulus Parameterizations under Summertime Midlatitude Continental Conditions

    SciTech Connect

    Xie, Shaocheng; Xu, Kuan-Man; Cederwall, Richard T.; Bechtold, Peter; Del Genio, Anthony D.; Klein, Stephen A.; Cripe, Douglas G.; Ghan, Steven J.; Gregory, David; Iacobellis, Sam F.; Krueger, Steven K.; Lohmann, Ulrike; Petch, Jon C.; Randall, David A.; Rotstayn, Leon D.; Somerville, Richard C.; Sud, Yogesh C.; Von Salzen, Knut; Walker, Gregory K.; Wolf, Audrey; Yio, Juhan J.; Zhang, Guang J.; Zhang, Minghua

    2002-04-01

    This study reports the Single-Column Model (SCM) part of the Atmospheric Radiation Measurement (ARM) / the Global Energy and Water-cycle Experiment (GEWEX) Cloud System Study (GCSS) joint SCM and Cloud-Resolving Model (CRM) Case 3 intercomparison study, with a focus on evaluation of cumulus parameterizations used in SCMs. Eight types of state-of-the-art cumulus parameterizations used in thirteen SCMs are evaluated under summertime midlatitude continental conditions using data collected at the ARM Southern Great Plains (SGP) site during the summer 1997 Intensive Operational Period (IOP). Cumulus mass fluxes estimated from ten CRMs are also used to diagnose problems in the SCMs. It is found that the cumulus parameterizations based on spectral cloud ensemble models are generally more active than those based on a bulk cloud model over midlatitude lands. Differences in the approaches that are used in determining the atmospheric instability in these two types of schemes are thought to be th e main reason. Most models with the former category of the parameterizations consistently show large systematic warm/dry biases in the troposphere. The errors are relatively small in those with the bulk mass flux schemes except for a model with a non-penetrative convection scheme, which shows large systematic cold/moist biases in the troposphere. It is also shown that surface precipitation rates produced by the models are mainly from cumulus clouds and surface stratiform precipitation rates are significantly underestimated. Finally, sensitivity of the results to different forcing approaches is briefly discussed. Results from the National Center for Atmospheric Research?s Community Climate Model (CCM3) SCM with improved triggering and closure assumptions are also discussed.

  16. The macroscopic entrainment processes of simulated cumulus ensemble. Part I: Entrainment sources

    SciTech Connect

    Lin, Chichung; Arakawa, A.

    1997-04-15

    Parameterization of cumulus convection requires a model that describes the statistical properties of a cumulus ensemble under given large-scale conditions. Such a model is called a cloud model for cumulus parameterization (CMCP). It would be best if the development of a CMCP were guided by synchronous observations covering a population of clouds. Unfortunately, observations for cumulus clouds are usually confined to individual clouds, leaving many uncertainties in designing a CMCP. In an attempt to improve the formulation of entrainment effects in a CMCP, the data simulated by a two-dimensional cloud-resolving model are used to investigate sources of entrainment into cumulus clouds. The authors first plot the Paluch diagram using the data from a nonprecipitating experiment. It is found that typical patterns on the Paluch diagram obtained by observational studies can be reproduced using the simulated data and can be interpreted in ways other than two-point mixing. The authors further examine entrainment sources through extensive trajectory analysis using the data from a precipitating experiment. They find that cloud air parcels at one level usually originate from locations of various heights, indicating a continuous series of entrainment events occurring throughout the cloud depth. However, the authors do not find a cloud air parcel decending more than several hundred meters. Penetrative downdrafts produced by mixing between cloud air and entrained air are not observed in the cases simulated. It seems that, as far as tropical deep convection is concerned, ignoring the contribution from descendent cloud air in a CMCP is an acceptable simplification. 52 refs., 14 figs.

  17. Characterization of FSH signalling networks in bovine cumulus cells: a perspective on oocyte competence acquisition.

    PubMed

    Khan, D R; Guillemette, C; Sirard, M A; Richard, F J

    2015-09-01

    Understanding the mechanisms regulating oocyte developmental competence is essential to enhance the clinical efficiency of assisted reproduction. FSH orchestrates the acquisition of oocyte competence, both in vivo and in vitro. Multiple pathways are implicated in FSH signalling; however, their precise coordination remains unresolved. A robust system to investigate FSH signalling is oocyte in vitro maturation (IVM) and we have previously demonstrated better bovine embryo development after FSH addition for the first 6 h during IVM. Using this model, we investigated FSH signalling in cumulus through transcriptomic and pharmacological tools. We demonstrate modulation of cumulus transcriptome by FSH mainly through protein kinase A (PKA) and epidermal growth factor (EGF) pathways. Differentially expressed transcripts were implicated in cumulus expansion, steroidogenesis, cell metabolism and oocyte competence. FSH required rouse-sarcoma oncogene (SRC) for EGF receptor transactivation. PKA and EGF pathway crosstalk was investigated using extracellular signal-regulated kinases (ERK1/2) phosphorylation as the functional end-point. FSH enhanced ERK1/2 activation by the EGF pathway with a simultaneous diminution through PKA. More specifically, FSH increased dual specific phosphatase (DUSP1) transcripts via PKA although DUSP1 protein did not change since EGF was required to prevent degradation. Our findings implicate FSH in PKA and EGF pathway activation, which interact to maintain appropriate levels of ERK1/2 phosphorylation and eventually cumulus expansion, metabolism and steroidogenesis. Moreover, considering the implication of the EGF pathway in GDF9 and BMP15 actions, our findings suggest that FSH may have a role in modulation of the cumulus response to oocyte-secreted factors. This information has implications for improvement of IVM and hence oocyte developmental competence.

  18. Transport in Rayleigh-stable experimental Taylor-Couette flow and granular electrification in a shaking experiment

    NASA Astrophysics Data System (ADS)

    Nordsiek, Freja

    This dissertation consists of two projects: Rayleigh-stable Taylor-Couette flow and granular electrification. Taylor-Couette flow is the fluid flow in the gap between two cylinders rotating at different rates. Azimuthal velocity profiles, dye visualization, and inner cylinder torques were measured on two geometrically similar Taylor-Couettes with axial boundaries attached to the outer cylinder, the Maryland and Twente T3C experiments. This was done in the Rayleigh stable regime, where the specific angular momentum increases radially, which is relevant to astrophysical and geophysical flows and in particular, stellar and planetary accretion disks. The flow substantially deviates from laminar Taylor-Couette flow beginning at moderate Reynolds number. Angular momentum is primarily transported to the axial boundaries instead of the outer cylinder due to Ekman pumping when the inner cylinder is rotating faster than the outer cylinder. A phase diagram was constructed from the transitions identified from torque measurements taken over four decades of the Reynolds number. Flow angular velocities larger and smaller than both cylinders were found. Together, these results indicate that experimental Taylor-Couette with axial boundaries attached to the outer cylinder is an imperfect model for accretion disk flows. Thunderstorms, thunder-snow, volcanic ash clouds, and dust storms all display lightning, which results from electrification of droplets and particles in the atmosphere. While lightning is fairly well understood (plasma discharge), the mechanisms that result in million-volt differences across the storm are not. A novel granular electrification experiment was upgraded and used to study some of these mechanisms in the lab. The relative importance of collective interactions between particles versus particle properties (material, size, etc.) on collisional electrification was investigated. While particle properties have an order of magnitude effect on the strength of

  19. Final environment impact report supplement: Northeast corridor improvement project electrification: New Haven, CT to Boston, MA. Final report

    SciTech Connect

    1995-02-01

    This document is a supplement to the final environmental impact report (FEIR) published in October 1994 on the proposal by the National Railroad Passenger Corporation (Amtrak) to complete the electrification of the Northeast Corridor main line by extending electrification from New Haven, CT, to Boston, MA. The purpose of this supplement is to provide additional information relative to: the Roxbury Substation Alternative Analysis; an expanded discussion on mitigation of potential adverse impacts; draft Section 61 findings; the Memorandum of Understanding between Amtrak and the Massachusetts Bay Transportation Authority (MBTA) for Route 128 Station; Amtrak`s draft outreach program; and to address other Massachusetts Environmental Policy Act concerns.

  20. A concept of wind-diesel hybrid systems for the electrification of small rural communities in Brazil

    SciTech Connect

    Pinho, J.T.; Bezerra, U.H.

    1997-12-31

    This work presents the concept of a wind-diesel hybrid system for the electrification of a small rural community in the Northern Region of Brazil, which can be used in many other places with similar characteristics. The system consists of two small diesel units and two wind turbines, one of which was designed and developed as a prototype with the purpose of gaining some insight in the field of wind turbine technology. Some considerations about small communities of the Northern Region of Brazil, and about electrification concepts are also made.

  1. Contact Electrification of Regolith Particles and Chloride Electrolysis: Synthesis of Perchlorates on Mars

    NASA Astrophysics Data System (ADS)

    Tennakone, K.

    2016-10-01

    Contact electrification of chloride-impregnated martian regolith particles due to eolian agitation and moisture condensation on coalesced oppositely charged grains may lead to spontaneous electrolysis that generates hypochlorite, chlorite, chlorate, and perchlorate with a concomitant reduction of water to hydrogen. This process is not curtailed even if moisture condenses as ice because chloride ionizes on the surface of ice. Limitations dictated by potentials needed for electrolysis and breakdown electric fields enable estimation of the required regolith grain size. The estimated dimension turns out to be of the same order of magnitude as the expected median size of martian regolith, and a simple calculation yields the optimum rate of perchlorate production.

  2. Les cooperatives et l'electrification rurale du Quebec, 1945--1964

    NASA Astrophysics Data System (ADS)

    Dorion, Marie-Josee

    Cette these est consacree a l'histoire de l'electrification rurale du Quebec, et, plus particulierement, a l'histoire des cooperatives d'electricite. Fondees par vagues successives a partir de 1945, les cooperatives rurales d'electricite ont ete actives dans plusieurs regions du Quebec et elles ont electrifie une partie significative des zones rurales. Afin de comprendre le contexte de la creation des cooperatives d'electricite, notre these debute (premiere partie) par une analyse du climat sociopolitique des annees precedant la naissance du systeme cooperatif d'electrification rurale. Nous y voyons de quelle facon l'electrification rurale devient progressivement, a partir de la fin des annees 1920, une question d'actualite a laquelle les divers gouvernements qui se succedent tentent de trouver une solution, sans engager---ou si peu---les fonds de l'Etat. En ce sens, la premiere etatisation et la mise sur pied d'Hydro-Quebec, en 1944, marquent une rupture quant au mode d'action privilegie jusque-la. La nouvelle societe d'Etat se voit cependant retirer son mandat d'electrifier le monde rural un an apres sa fondation, car le gouvernement Duplessis, de retour au pouvoir, prefere mettre en place son propre modele d'electrification rurale. Ce systeme repose sur des cooperatives d'electricite, soutenues par un organisme public, l'Office de l'electrification rurale (OER). L'OER suscite de grandes attentes de la part des ruraux et c'est par centaines qu'ils se manifestent. Cet engouement pour les cooperatives complique la tache de l'OER, qui doit superviser de nouvelles societes tout en assurant sa propre organisation. Malgre des hesitations et quelques delais introduits par un manque de connaissances techniques et de personnel qualifie, les commissaires de l'OER se revelent perspicaces et parviennent a mettre sur pied un systeme cooperatif d'electrification rurale qui produit des resultats rapides. Il leur faudra cependant compter sur l'aide des autres acteurs engages

  3. Rural electrification in multiethnic Arizona: A study of power, urbanization and change

    NASA Astrophysics Data System (ADS)

    Glaser, Leah Suzanne

    2002-01-01

    From as early as the 1880s until as late as the 1970s, electrical power served as a critical tool for bringing America's diverse western communities into an urban industrial era. This study examines the process of electrification in three demographically diverse rural regions of Eastern Arizona. These three regions include the valleys of the Southeast, the White Mountains, and the Navajo Reservation to the north. While federal programs aided rural residents, local and regional factors determined the timing and nature of electrification and its impact. Access to electricity depended upon economics and technological advances, as well as a combination of local community and regional characteristics such as location, landscape, demographics, politics, and culture. At the turn of the century, electricity, with its elaborate and extensive infrastructure of wires, towers, and poles, emerged across America's cultural landscapes as the industrial era's most prominent symbol of progress, power, and a modern, urban lifestyle. Technological innovations and mechanization flourished, but primarily in the urban areas of the Northeast. People living outside concentrated settlements, of all ethnic backgrounds, had few hopes for delivery due to the cost of building power lines to a limited market. Arizona's rural population has historically been ethnically diverse, and its landscape varies from desert valleys to mountains of alpine forest. The federal government owns much of the land. Aided by federal guidance and funding sources like the New Deal's Rural Electrification Administration (REA), the existing rural communities took the initiative and constructed electrical systems specific to their local and regional needs. While products of the communities that built them, these systems symbolized and defined newly urbanized regions within the context of old rural landscapes, lifestyles, and traditions. In some ways the rural electrification process urbanized rural Arizona. The

  4. Overview of the Cumulus Humilis Aerosol Processing Study.

    SciTech Connect

    Berg, L. K.; Berkowitz, C. M.; Ogren, J. A.; Hostetler, C. A.; Ferrare, R. A.; Dubey, M.; Andrews, E.; Coulter, R. L.; Hair, J. W.; Hubbe, J. M.Lee, Y. N.; Mazzoleni, C; Olfert, J; Springston, SR; Environmental Science Division; PNNL; NOAA Earth System Research Lab.; NASA Langley Research Center; LANL; BNL; Univ.of Alberta; Univ. of Colorado

    2009-11-01

    Aerosols influence climate directly by scattering and absorbing radiation and indirectly through their influence on cloud microphysical and dynamical properties. The Intergovernmental Panel on Climate Change (IPCC) concluded that the global radiative forcing due to aerosols is large and in general cools the planet. But the uncertainties in these estimates are also large due to our poor understanding of many of the important processes related to aerosols and clouds. To address this uncertainty an integrated strategy for addressing issues related to aerosols and aerosol processes was proposed. Using this conceptual framework, the Cumulus Humilis Aerosol Processing Study (CHAPS) is a stage 1 activity, that is, a detailed process study. The specific focus of CHAPS was to provide concurrent observations of the chemical composition of the activated [particles that are currently serving as cloud condensation nuclei (CCN)] and nonactivated aerosols, the scattering and extinction profiles, and detailed aerosol and droplet size spectra in the vicinity of Oklahoma City, Oklahoma, during June 2007. Numerous campaigns have examined aerosol properties downwind from large pollution sources, including the Megacity Initiative: Local and Global Research Observations (MILAGRO) campaign and the two of the three Aerosol Characterization Experiments, ACE-2 and ACE-Asia. Other studies conducted near cities have examined changes in both aerosols and clouds downwind of urban areas. For example wintertime stratiform clouds associated with the urban plumes of Denver, Colorado, and Kansas City, Missouri, have a larger number concentration and smaller median volume diameter of droplets than clouds that had not been affected by the urban plume. Likewise, a decrease in precipitation in polluted regions along the Front Range of the Rocky Mountains was discovered. In a modeling study, it was found that precipitation downwind of urban areas may be influenced by changes in aerosols as well as the

  5. Individual bovine in vitro embryo production and cumulus cell transcriptomic analysis to distinguish cumulus-oocyte complexes with high or low developmental potential.

    PubMed

    Bunel, A; Jorssen, E P; Merckx, E; Leroy, J L; Bols, P E; Sirard, M A

    2015-01-15

    Studying cumulus cell (CC) transcriptome is of great interest as it could provide a noninvasive method to assess oocyte quality. In cattle, the search for quality markers has not been done with cumulus-oocyte complexes (COCs) cultured individually from maturation to blastocyst stage. Here, differences between high- and low-potential COCs were examined by transcriptomic analysis of CC biopsies obtained from COCs of 2 to 6 mm follicles (n = 249; eight replicates) before individual in vitro maturation, fertilization, and culture until Day 8 after fertilization. Each COC was individually tracked and categorized based on his fate: embryo at blastocyst stage (CC-Blast) or embryo arrested at 2- to 8-cell stage (CC-2-8-cells). Average blastocyst rates were 27.7% for individual culture and 31.2% for group control (not significantly different). For transcriptomic analysis, five cumulus biopsies per replicate were pooled for each fate. Three CC replicates underwent transcriptomic analysis using RNA microarray assay. Some clear differences in gene expression between the CC-Blast and the CC-2-8-cell groups were identified. Considering a 1.5-fold change (P < 0.05), 68 genes were differentially expressed between the CC-Blast and CC-2-8-cells. Quantitative reverse transcription-polymerase chain reaction validations were performed for 12 selected genes: six upregulated genes for each COC fate. Higher expression of 1-acylglycerol-3-phosphate O-acyltransferase 9 (AGPAT9) (lipid metabolism), Chloride intracellular channel 3 (CLIC3), Keratin 8 (KRT8), and Lumican (LUM) (molecular transport) was observed in CC-2-8-cells (P < 0.05). The CC-Blast fate analysis revealed a significantly higher expression of Glycine amidinotransferase (L-arginine:glycine amidinotransferase) (GATM) (posttranslational modification, amino acid metabolism, and free radical scavenging). This newly identified set of genes could provide new markers to distinguish COCs associated with good quality embryos from COCs

  6. Photovoltaics for rural electrification in the People`s Republic of China

    SciTech Connect

    Wallace, W.L.; Tsuo, Y.S.

    1997-12-31

    Rapid growth in economic development coupled with the absence of an electric grid in large areas of the rural countryside have created a need for new energy sources both in urban centers and rural areas in China. The most critical need for rural electrification exists in northern and western China, where 120 million rural people have no access to grid electricity, and in over 300 coastal islands that are unelectrified. The availability of solar and wind resources tends to correlate highest with those regions of China where the population density is low and grid extension is too costly and impractical to reach the rural population. In February, 1995, the US Department of Energy signed an Energy Efficiency and Renewable Energy Protocol Agreement with the Chinese State Science and Technology Commission in Beijing, China. Under this agreement, the National Renewable Energy Laboratory (NREL) is providing assistance to several central government and provincial government agencies in China to develop photovoltaic and photovoltaic hybrid systems for rural electrification.

  7. Dependence of contact electrification on the magnitude of strain in polymeric materials

    NASA Astrophysics Data System (ADS)

    Sow, Mamadou; Lacks, Daniel J.; Mohan Sankaran, R.

    2012-10-01

    We present a new experimental approach to systematically study the effect of material strain on contact electrification. Thin sheets of latex rubber are variably strained by stretching over a hollow cylinder, analogous to a drum. The strained sheets are repeatedly contacted with another surface by a computer-controlled apparatus. The surface potential on the latex rubber is measured in real time by a non-contact electrostatic voltmeter. For unstrained latex rubber, we find that contact with polytetrafluoroethylene (PTFE) leads to a negative surface potential that progressively increases in magnitude to more negative values with increasing number of contacts. When the latex rubber is strained, contact with PTFE causes the surface potential of the latex rubber to shift to less negative values. At strains of more than ˜50%, the polarity of the surface potential is reversed, such that contact with PTFE causes the latex rubber to charge positively. These results indicate that contact electrification intimately depends on the degree of material strain, and may explain how spatial inhomogeneities of charge exist on contacted surfaces and why there is a lack of reproducibility in contact charging experiments.

  8. Electrification of sand on Titan and its influence on sediment transport

    NASA Astrophysics Data System (ADS)

    Méndez Harper, J. S.; McDonald, G. D.; Dufek, J.; Malaska, M. J.; Burr, D. M.; Hayes, A. G.; McAdams, J.; Wray, J. J.

    2017-03-01

    Triboelectric, or frictional, charging is a ubiquitous yet poorly understood phenomenon in granular flows. Recognized in terrestrial volcanic plumes and sand storms, such electrification mechanisms are possibly present on Titan. There, dunes and plains of low-density organic particles blanket extensive regions of the surface. Unlike Earth, Titan hosts granular reservoirs whose physical and chemical properties possibly enhance the effects of charging on particle motion. Here we demonstrate in laboratory tumbler experiments under atmospheric conditions and using organic materials analogous to Titan that Titan sands can readily charge triboelectrically. We suggest that the resulting electrostatic forces are strong enough to promote aggregation of granular materials and affect sediment transport on Titan. Indeed, our experiments show that electrostatic forces may increase the saltation threshold for grains by up to an order of magnitude. Efficient electrification may explain puzzling observations on Titan such as the mismatch between dune orientations and inferred wind fields. We conclude that, unlike other Solar System bodies, nanometre-scale electrostatic processes may shape the geomorphological features of Titan across the moon’s surface.

  9. Direct numerical simulation of powder electrification in a turbulent channel flow

    NASA Astrophysics Data System (ADS)

    Grosshans, Holger; Papalexandris, Miltiadis

    2016-11-01

    Particle electrification is often encountered in process industries. Sometimes it has useful applications, such as the control of particle trajectories through an electric field. In other situations is has negative effects. For example, during pneumatic transport it can cause particle deposition or, even worse, spark discharges and subsequent fires and explosions. Despite its frequent occurrence, due to the complexity of the underlying physical mechanisms, there are still many open questions regarding particle electrification and inconsistent theoretical predictions have been reported. The objective of our work is to gain a better understanding and physical insight of this phenomenon. To this end, we performed Direct Numerical Simulations to analyze the turbulent flow of a carrier fluid with immersed particles in a channel. Moreover, the motion of the particles was computed in a Lagrangian framework and dynamic models accounting for the particle-wall and particle-particle charge exchange were implemented. In our talk, we discuss in detail the effect of the fluid turbulence to the build-up of the electrostatic charge of the particles. Furthermore, we elaborate on the influence of the particle Stokes number and gravitational forces to the process of powder charging. Supported by the National Research Fund of Belgium (FNRS) under the GRANMIX Projet de Recherche Grant.

  10. Rhythm Pattern of Sole through Electrification of the Human Body When Walking

    NASA Astrophysics Data System (ADS)

    Takiguchi, Kiyoaki; Wada, Takayuki; Tohyama, Shigeki

    The rhythm of automatic cyclic movements such as walking is known to be generated by a rhythm generator called CPG in the spinal cord. The measurement of rhythm characteristics in walking is considered to be important for analyzing human bipedal walking and adaptive walking on irregular terrain. In particular, the soles that contact the terrain surface perform flexible movements similar to the movement of the fins of a lungfish, which is considered to be the predecessor of land animals. The sole movements are believed to be a basic movement acquired during prehistoric times. The detailed rhythm pattern of sole motion is considered to be important. We developed a method for measuring electrification without installing device on a subject's body and footwear for stabilizing the electrification of the human body. We measured the rhythm pattern of 20 subjects including 4 infants when walking by using this system and the corresponding equipment. Therefore, we confirmed the commonality of the correlative rhythm patterns of 20 subjects. Further, with regard to an individual subject, the reproducibility of a rhythm pattern with strong correlation coefficient > 0.93 ± 0.5 (mean ± SD) concerning rhythms of trials that are differently conducted on adult subjects could be confirmed.

  11. Patronage power: Rural electrification, river development, and Lyndon Johnson (1937--1939)

    NASA Astrophysics Data System (ADS)

    Dusek, Paul-Michael Mays

    Few historians document Lyndon Johnson's efforts to construct a state-wide political machine at the local level early in his congressional career. The literature glorifies Johnson for hydroelectric river development and rural electrification. This thesis acknowledges the transformative nature of rural electrification in Central Texas through the efforts of Johnson but, more importantly, reveals how extensively Johnson sought to capitalize on the tail-end of the New Deal to utilize government-funded relief projects to establish a state-wide political machine. An analysis of the correspondence between Johnson, his local political operators, members of his state-wide network, and rural constituents reveals another layer to the complexity of Johnson and further exposes his ambitious, calculating nature. Johnson used rural electrification to first create a community of supporters in his congressional district then used rural electrification and multipurpose river development programs to cultivate political contacts across the state of Texas. This thesis explores the first time that Lyndon Johnson used patronage to develop a political community as a publicly elected official. Johnson pushed for constant expansion of operations to ensure a steady supply of new jobs while displaying a cavalier attitude about specific regulations regarding the allocation of funds. His machine manipulated and massaged congressional appropriations restrictions and utilized multiple congressional revenue streams to stretch finances further and lower overhead costs to increase the scope of operations thus further improving the lives of his constituents. Johnson also used this movement to efficiently and effectively construct a foundation for his political machine. This thesis also clarifies an early moment in Johnson's beliefs about civil rights. Instead of standing on principle, Johnson relied on extortion and threats to fight racism at this early juncture in his political career because of

  12. Case studies of size resolved CCN composition and cloud properties in cumulus humilis

    NASA Astrophysics Data System (ADS)

    Yu, X.; Berg, L. K.; Berkowitz, C. M.; Lee, Y.; Alexander, L.; Ogren, J. A.; Andrews, B.

    2010-12-01

    The Cumulus Humilis Aerosol Processing Study (CHAPS) provided a unique opportunity to study cloud processing of aerosols. Clouds play an active role in the processing and cycling of atmospheric constituents. Within in a cloud, gases and particles can partition to cloud droplets by absorption and condensation as well as activation and impact scavenging. The Department of Energy (DOE) G-1 aircraft was used as one of the main platforms in CHAPS. G-1 flight tracks were designed to characterize aerosols at cloud top and cloud base as well as within individual cumulus humilis (or fair-weather cumulus), in the vicinity of Oklahoma City. Measurements of interstitial aerosols and residuals of activated condensation cloud nuclei were conducted simultaneously. The interstitial aerosols were measured downstream of an isokinetic inlet, and the activated particles downstream of a counter-flow virtual impactor (CVI). The sampling line to the Aerodyne Aerosol Mass Spectrometer (AMS) was switched between the isokinetic inlet and the CVI to allow characterization of non-activated particles outside of clouds in contrast to particles activated in clouds. Trace gases including ozone, carbon monoxide, sulfur dioxide, and a series of volatile organic compounds (VOCs) were measured. Key meteorological state parameters included liquid water content, cloud drop size, and dew point. In this presentation, we will focus on case studies of CCN properties in cumulus humilis. The first analysis summarizes three case studies of measurements made at cloud bottom and in-cloud by the AMS. The size-resolved composition is different between background and activated particles. The second analysis links in situ measurements of aerosol, trace gas, and VOCs to look into the sources of CCN. For instance, by comparing the characteristic m/z ratios by AMS and tracers like CO or isoprene, one can gain more insight into the role of primary and secondary organic aerosols in CCN and background aerosols. The third

  13. Cumulus expansion, nuclear maturation and connexin 43, cyclooxygenase-2 and FSH receptor mRNA expression in equine cumulus-oocyte complexes cultured in vitro in the presence of FSH and precursors for hyaluronic acid synthesis

    PubMed Central

    Dell'Aquila, Maria Elena; Caillaud, Maud; Maritato, Filippo; Martoriati, Alain; Gérard, Nadine; Aiudi, Giulio; Minoia, Paolo; Goudet, Ghylène

    2004-01-01

    The aim of this study was to investigate cumulus expansion, nuclear maturation and expression of connexin 43, cyclooxygenase-2 and FSH receptor transcripts in equine cumuli oophori during in vivo and in vitro maturation in the presence of equine FSH (eFSH) and precursors for hyaluronic acid synthesis. Equine cumulus-oocyte complexes (COC) were cultured in a control defined medium supplemented with eFSH (0 to 5 micrograms/ml), Fetal Calf Serum (FCS), precursors for hyaluronic acid synthesis or glutamine according to the experiments. After in vitro maturation, the cumulus expansion rate was increased with 1 microgram/ml eFSH, and was the highest with 20% FCS. It was not influenced by precursors for hyaluronic acid synthesis or glutamine. The expression of transcripts related to cumulus expansion was analyzed in equine cumulus cells before maturation, and after in vivo and in vitro maturation, by using reverse transcription-polymerase chain reaction (RT-PCR) with specific primers. Connexin 43, cyclooxygenase-2 (COX-2) and FSH receptor (FSHr) mRNA were detected in equine cumulus cells before and after maturation. Their level did not vary during in vivo or in vitro maturation and was influenced neither by FSH nor by precursors for hyaluronic acid synthesis. Results indicate that previously reported regulation of connexin 43 and COX-2 proteins during equine COC maturation may involve post-transcriptional mechanisms. PMID:15212696

  14. Dynamic changes of connexin-43, gap junctional protein, in outer layers of cumulus cells are regulated by PKC and PI 3-kinase during meiotic resumption in porcine oocytes.

    PubMed

    Shimada, M; Maeda, T; Terada, T

    2001-04-01

    Mammalian oocytes are surrounded by numerous layers of cumulus cells, and the loss of gap junctional communication in the outer layers of cumulus cells induces meiotic resumption in oocytes. In this study, we investigated the dynamic changes in the gap junctional protein connexin-43 in cumulus cells during the meiotic resumption of porcine oocytes. The amount of connexin-43 in all layers of cumulus cells recovered from cumulus-oocyte complexes was increased after 4-h cultivation. However, at 12-h cultivation, the positive signal for connexin-43 immunoreactivity was markedly reduced in the outer layers of cumulus cells. When these reductions of connexin-43 were blocked by protein kinase C (PKC) or phosphatidylinositol (PI) 3-kinase inhibitor, networks of filamentous bivalents (i.e., advanced chromosomal status) were undetectable in the germinal vesicle of the oocyte. After 28-h cultivation, when the majority of oocytes were reaching the metaphase I (MI) stage, the connexin-43 in the inner layers of cumulus cells was phosphorylated, regardless of mitogen-activated protein (MAP) kinase activation. These results suggest that the initiation of meiotic resumption, namely, the formation of networks of filamentous bivalents in germinal vesicle, is associated with the reduction of gap junctional protein connexin-43 in the outer layers of cumulus cells via the PKC and/or PI 3-kinase pathway. Moreover, the connexin-43 in the inner layers of cumulus cells is phosphorylated during meiotic progression beyond the MI stage, regardless of MAP kinase activation in cumulus cells surrounding the oocyte.

  15. Effect of initial cumulus morphology on meiotic dynamic and status of mitochondria in horse oocytes during IVM.

    PubMed

    Torner, H; Alm, H; Kanitz, W; Goellnitz, K; Becker, F; Poehland, R; Bruessow, K-P; Tuchscherer, A

    2007-04-01

    The aim of this investigation was to examine the chromatin configuration of the nucleus, pattern of mitochondrial aggregation and mitochondrial activity in parallel studies in the same horse oocytes. Horse oocytes recovered by ultrasound-guided follicle aspiration in vivo were classified according to two main initial cumulus morphologies as having compact or expanded cumulus. The percentage of oocytes with a diplotene meiotic configuration at the time of recovery from the follicles was highest in compact oocytes. Oocytes with expanded cumulus layers at the time of recovery matured more rapidly in vitro and reached a proportion >50% at the metaphase II stage (M 2) sooner during in vitro maturation (IVM), than did compact oocytes. The mitochondrial aggregation pattern changed from finely distributed (Type 1) through crystalline (Type 2) to an aggregated, granulated appearance (Type 3) during IVM. The pattern of mitochondrial aggregation at the time of recovery was associated with the initial cumulus morphology of the oocyte, in that compact oocytes had a higher proportion of Type 1 aggregation, whereas expanded oocytes had a higher proportion of Type 3. The fluorescence intensity of metabolic active mitochondria, measured by fluorescence intensity (Em 570) per oocyte after MitoTracker CMTM Ros orange labelling, increased in the oocytes during IVM and depended on initial cumulus investment. Oocytes with the granulated type of aggregated mitochondria Type 3 had the highest level of metabolic activity and were in more progressed stages of meiosis (A 1-M 2). Oocytes initially having expanded layers of cumulus reached significantly higher levels of mitochondrial activity after IVM than did oocytes initially having compact cumuli. During resumption of meiosis the mitochondrial activity of oocytes with initially expanded cumulus increased continuously up to M 2, whereas in oocytes from compact cumulus-oocyte complex (COC), the activity declined after A 1/T 1 stages of

  16. Contributions to the implementation of the Arakawa-Schubert cumulus parameterization in the GLA GCM

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Chao, W. C.; Walker, G. K.

    1989-01-01

    The AS scheme in the Goddard Laboratory for Atmospheres General Circulation Model is used to address two fundamental problems of simulated cumulus convection and rainfall. The first problem is that of too much rainfall in the tropics at initial time and the second is the problem of too vigorous a hydrologic cycle in the tropics even after the initial adjustment period. A number of experiments were performed, including an investigation of the influence of the prescribed limiting values of critical cloud work formation (CCWF). It is concluded that the CCWF plays a useful role in the apportionment of the rainfall into convective and large-scale components. Related experiments reveal the nature of the interaction between atmospheric circulation and the cumulus processes.

  17. Impact of a scale-aware cumulus parameterization in an operational NWP system modeling system

    NASA Astrophysics Data System (ADS)

    Chen, Baode; Yang, Yuhua; Wang, Xiaofeng

    2014-05-01

    To better understand the behavior of convective schemes across the grey zone, we carried out one-month (July of 2013) realtime-like experiment with an operational NWP system modeling system which includes the ADAS data assimilation scheme and WRF forecast model. The Grell-Freitas cumulus parameterization scheme, which is a scale-aware convective parameterization scheme and has been developed to better handle the transition in behavior of the sub-grid scale convective processes through the grey zone, was used in different resolution (15km, 9km and 3km) model set-up. Subjective and quantitative evaluations of the forecasts were conducted and the skills of the different experimental forecasts relatively to existing forecasting guidance were compared. A summary of the preliminary findings about the proportion of resolved vs unresolved physical processes in the gray zone will be presented along with a discussion of the potential operational impacts of the cumulus parameterization.

  18. Derivation of Patient Specific Pluripotent Stem Cells Using Clinically Discarded Cumulus Cells

    PubMed Central

    Xu, Jie; Lin, Chen-Ju; Wang, Sheng-Wen; Cheng, An-Sheng; Lu, Jean; Lu, Chung-Hao; Sung, Li-Ying

    2016-01-01

    Induced pluripotent stem cells (iPSCs) are powerful tools for basic and translational research, as well as regenerative medicine. In routine human in vitro fertilization (IVF) practices, cumulus cells (CCs) are discarded, representing a potential source of biological materials for regenerative medicine. In this study, we derived patient-specific iPSCs using CCs from human infertility clinics for the first time. The human cumulus cell derived iPSCs (hc-iPSCs) were characterized for growth, karyotype, expression of pluripotency genes, and were subjected to embryoid bodies (EBs) and teratoma assays to evaluate their differentiation capacity. Hc-iPSCs display typical iPSC characteristics, and are capable of differentiating into all germ layers in vitro and in vivo. We further show that putative primordial germ cell like cells (PGCLCs) can be derived using hc-iPSCs. Our data demonstrate the feasibility of deriving patient-specific pluripotent stem cells using CCs. PMID:27802323

  19. Effects of cumulus entrainment and multiple cloud types on a January global climate model simulation

    NASA Technical Reports Server (NTRS)

    Yao, Mao-Sung; Del Genio, Anthony D.

    1989-01-01

    An improved version of the GISS Model II cumulus parameterization designed for long-term climate integrations is used to study the effects of entrainment and multiple cloud types on the January climate simulation. Instead of prescribing convective mass as a fixed fraction of the cloud base grid-box mass, it is calculated based on the closure assumption that the cumulus convection restores the atmosphere to a neutral moist convective state at cloud base. This change alone significantly improves the distribution of precipitation, convective mass exchanges, and frequencies in the January climate. The vertical structure of the tropical atmosphere exhibits quasi-equilibrium behavior when this closure is used, even though there is no explicit constraint applied above cloud base.

  20. The Role of Cloud-Scale Resolution on Radiative Properties of Oceanic Cumulus Clouds

    SciTech Connect

    Kassianov, Evgueni I.; Ackerman, Thomas P.; Kollias, Pavlos

    2005-03-01

    Both individual and combined effects of the horizontal and vertical variability of cumulus clouds on solar radiative transfer were investigated using a two-dimensional (x- and z-directions) cloud radar dataset. This high-resolution dataset of typical fair-weather marine cumulus was derived from ground-based 94-GHz cloud radar observations. The domain-averaged (along x-direction) radiative properties were computed by a Monte Carlo method. It is shown that (1) different cloud-scale resolutions can be used for accurate calculations of the mean absorption, upward and downward fluxes; (2) the resolution effects can depend strongly on the solar zenith angle; and (3) a few cloud statistics can be successfully applied for calculating the averaged radiative properties.

  1. A study of conditional instability of the second kind /CISK/. [tropical storm cumulus cloud activity

    NASA Technical Reports Server (NTRS)

    Chao, W. C.

    1979-01-01

    The theory of interaction between the cumulus clouds and the large-scale field proposed by Arakawa and Schubert (1974) is used to reexamine the CISK mechanism. After a qualitative discussion, a quantitative study is presented, using a three-level approach. The difference between the cases with conditional and unconditional heating formulations are discussed, and growth rate is treated as an eigenvalue problem. To confirm the results obtained and to extend the study to a case where the basic thermodynamic structure varies in the horizontal direction, the CISK mechanism is analyzed by an initial-value-problem approach. One of the findings is that the cumulus heating formulation of Arakawa and Schubert, through its scale dependence, is an improvement over previous CISK studies.

  2. A study of conditional instability of the second kind /CISK/. [tropical storm cumulus cloud activity

    NASA Technical Reports Server (NTRS)

    Chao, W. C.

    1979-01-01

    The theory of interaction between the cumulus clouds and the large-scale field proposed by Arakawa and Schubert (1974) is used to reexamine the CISK mechanism. After a qualitative discussion, a quantitative study is presented, using a three-level approach. The difference between the cases with conditional and unconditional heating formulations are discussed, and growth rate is treated as an eigenvalue problem. To confirm the results obtained and to extend the study to a case where the basic thermodynamic structure varies in the horizontal direction, the CISK mechanism is analyzed by an initial-value-problem approach. One of the findings is that the cumulus heating formulation of Arakawa and Schubert, through its scale dependence, is an improvement over previous CISK studies.

  3. Dependence of entrainment in shallow cumulus convection on vertical velocity and distance to cloud edge

    NASA Astrophysics Data System (ADS)

    Tian, Yang; Kuang, Zhiming

    2016-04-01

    The dependence of entrainment rate on environmental conditions and cloud characteristics is investigated using large eddy simulations (LES) of the response of shallow cumulus convection to a small-amplitude temperature perturbation that is horizontally uniform and localized in height. The simulated cumulus fields are analyzed in the framework of an ensemble of entraining plumes by tracking a large number of Lagrangian parcels embedded in the LES and grouping them into different plumes based on their detrainment heights. The results show that fractional entrainment rate per unit height of a plume is inversely proportional to the plume's vertical velocity and its distance to the cloud edge, while changes in environmental stratification and relative humidity, the plume's buoyancy, or the vertical gradient of its buoyancy due to the temperature perturbation have little effect on the plume's entrainment rate.

  4. Interaction of a cumulus cloud ensemble with the large-scale environment. II

    NASA Technical Reports Server (NTRS)

    Lord, S. J.; Arakawa, A.

    1980-01-01

    The closure assumption of the Arakawa-Schubert (1974) cumulus parameterization is examined with attention to the kinetic energy budget of a cumulus subensemble. It is concluded that dissipation should depend primarily on cloud type, and that cloud-work functions calculated under different synoptic conditions should consequently be quasi-constant for each cloud type. Observational evidence for the cloud-work function quasi-equilibrium is presented. Cloud-work functions are calculated from a variety of data sets in the tropics and subtropics. The results demonstrate that the cloud-work functions fall into a well-defined narrow range for each subensemble, although the thermodynamical vertical structures for each data set are quite different.

  5. Shallow-cumulus cloud feedback: model uncertainties and perspectives of observational constraint

    NASA Astrophysics Data System (ADS)

    Bony, Sandrine

    2017-04-01

    Shallow-cumulus clouds constitute the most prominent cloud type on Earth, and their response to changing environmental conditions is critical for climate sensitivity. Research over the last decade has pointed out the importance of the interplay between clouds, convection, turbulence and circulation in controlling this response. Unfortunately, numerical models represent this interplay in diverse ways, which translates into different shallow-cumulus cloud feedbacks in climate change. Climate models predict that the cloud-base cloud fraction is very sensitive to changes in environmental conditions, while process models suggest that it is very resilient to such changes. To understand and solve this contradiction, a field campaign named EUREC4A (Elucidating the role of clouds-circulation coupling in climate) will be organized in the lower Atlantic trades in Jan-Fev 2020. The scientific objectives of this campaign will be presented, and the experimental strategy envisioned to reach these objectives will be discussed.

  6. Modification of cumulus convection and planetary boundary layer schemes in the GRAPES global model

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Chen, Qiying; Sun, Jian

    2015-10-01

    Cumulus convection is a key linkage between hydrological cycle and large-scale atmospheric circulation. Cumulus parameterization scheme is an important component in numerical weather and climate modeling studies. In the Global/Regional Assimilation and Prediction Enhanced System (GRAPES), turbulent mixing and diffusion approach is applied in its shallow convection scheme. This method overestimates the vertical transport of heat and moisture fluxes but underestimates cloud water mixing ratio over the region of stratocumulus clouds. As a result, the simulated low stratocumulus clouds are less than observations. To overcome this problem, a mass flux method is employed in the shallow convection scheme to replace the original one. Meanwhile, the deep convection scheme is adjusted correspondingly. This modification is similar to that in the US NCEP Global Forecast System (GFS), which uses the simplified Arakawa Schubert Scheme (SAS). The planetary boundary layer scheme (PBL) is also revised by considering the coupling between the PBL and stratocumulus clouds. With the modification of both the cumulus and PBL schemes, the GRAPES simulation of shallow convective heating rate becomes more reasonable; total amounts of stratocumulus clouds simulated over the eastern Pacific and their vertical structure are more consistent with observations; the underestimation of stratocumulus clouds simulated by original schemes is less severe with the revised schemes. Precipitation distribution in the tropics becomes more reasonable and spurious precipitation is effectively suppressed. The westward extension and northward movement of the western Pacific subtropical high simulated with the revised schemes are more consistent with Final Operational Global Analysis (FNL) than that simulated with the original schemes. The statistical scores for the global GRAPES forecast are generally improved with the revised schemes, especially for the simulation of geopotential height in the Northern

  7. Observations of rapid aerosol optical depth enhancements in the vicinity of polluted cumulus clouds

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Arola, A.; Ferrare, R. A.; Hostetler, C. A.; Crumeyrolle, S. N.; Berkoff, T. A.; Welton, E. J.; Lolli, S.; Lyapustin, A.; Wang, Y.; Schafer, J. S.; Giles, D. M.; Anderson, B. E.; Thornhill, K. L.; Minnis, P.; Pickering, K. E.; Loughner, C. P.; Smirnov, A.; Sinyuk, A.

    2014-07-01

    During the July 2011 DISCOVER-AQ field experiment in Maryland, significant enhancements in AERONET sun-sky radiometer measured AOD were observed in the immediate vicinity of non-precipitating cumulus clouds on some days. Both measured Angstrom exponents and aerosol size distribution retrievals made before, during and after cumulus development often suggest little change in fine mode particle size, therefore implying possible new particle formation in addition to cloud processing and humidification of existing particles. In addition to sun/sky radiometer measurements of large enhancements of fine mode AOD, lidar measurements made from both ground-based and aircraft-based instruments during the experiment also measured large increases in aerosol signal at altitudes associated with the presence of fair weather cumulus clouds. These data show modifications of the aerosol vertical profile as a result of the aerosol enhancements at and below cloud altitudes. The airborne lidar data were utilized to estimate the spatial extent of these aerosol enhancements, finding increased AOD, backscatter and extinction out to 2.5 km distance from the cloud edge. Furthermore, in situ measurements made from aircraft vertical profiles over an AERONET site during the experiment also showed large increases in aerosol scattering and aerosol volume after cloud formation as compared to before. The 15 year AERONET database of AOD measurements at the GSFC, Maryland site was investigated in order to obtain a climatological perspective of this phenomenon of AOD enhancement. Analysis of the diurnal cycle of AOD in summer showed significant increases in AOD from morning until late afternoon, corresponding to the diurnal cycle of cumulus development.

  8. Observations of rapid aerosol optical depth enhancements in the vicinity of polluted cumulus clouds

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Arola, A.; Ferrare, R. A.; Hostetler, C. A.; Crumeyrolle, S. N.; Berkoff, T. A.; Welton, E. J.; Lolli, S.; Lyapustin, A.; Wang, Y.; Schafer, J. S.; Giles, D. M.; Anderson, B. E.; Thornhill, K. L.; Minnis, P.; Pickering, K. E.; Loughner, C. P.; Smirnov, A.; Sinyuk, A.

    2014-11-01

    During the July 2011 Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field experiment in Maryland, significant enhancements in Aerosol Robotic Network (AERONET) sun-sky radiometer measured aerosol optical depth (AOD) were observed in the immediate vicinity of non-precipitating cumulus clouds on some days. Both measured Ångström exponents and aerosol size distribution retrievals made before, during and after cumulus development often suggest little change in fine mode particle size; therefore, implying possible new particle formation in addition to cloud processing and humidification of existing particles. In addition to sun-sky radiometer measurements of large enhancements of fine mode AOD, lidar measurements made from both ground-based and aircraft-based instruments during the experiment also measured large increases in aerosol signal at altitudes associated with the presence of fair weather cumulus clouds. These data show modifications of the aerosol vertical profile as a result of the aerosol enhancements at and below cloud altitudes. The airborne lidar data were utilized to estimate the spatial extent of these aerosol enhancements, finding increased AOD, backscatter and extinction out to 2.5 km distance from the cloud edge. Furthermore, in situ measurements made from aircraft vertical profiles over an AERONET site during the experiment also showed large increases in aerosol scattering and aerosol volume after cloud formation as compared to before. The 15-year AERONET database of AOD measurements at the Goddard Space Flight Center (GSFC), Maryland site, was investigated in order to obtain a climatological perspective of this phenomenon of AOD enhancement. Analysis of the diurnal cycle of AOD in summer showed significant increases in AOD from morning to late afternoon, corresponding to the diurnal cycle of cumulus development.

  9. Parameterization of GCM Subgrid nonprecipitating cumulus and stratocumulus clouds using stochastic/phenomenological methods

    SciTech Connect

    Stull, R.B.

    1992-08-26

    A theory was developed for the fraction of near-surface air likely to form forced and active cumulus clouds. This stochastic method is based on a 2-D frequency distribution of the occurrence of various buoyancy and condensation levels in air near the surface, and the relationship of this distribution to the mean temperature profile. An alternative form of this theory utilizes a 2-D distribution of convective available potential energies (CAPE) instead of virtual potential temperatures.

  10. Mechanisms and Model Diversity of Trade-Wind Shallow Cumulus Cloud Feedbacks: A Review

    NASA Astrophysics Data System (ADS)

    Vial, Jessica; Bony, Sandrine; Stevens, Bjorn; Vogel, Raphaela

    2017-07-01

    Shallow cumulus clouds in the trade-wind regions are at the heart of the long standing uncertainty in climate sensitivity estimates. In current climate models, cloud feedbacks are strongly influenced by cloud-base cloud amount in the trades. Therefore, understanding the key factors controlling cloudiness near cloud-base in shallow convective regimes has emerged as an important topic of investigation. We review physical understanding of these key controlling factors and discuss the value of the different approaches that have been developed so far, based on global and high-resolution model experimentations and process-oriented analyses across a range of models and for observations. The trade-wind cloud feedbacks appear to depend on two important aspects: (1) how cloudiness near cloud-base is controlled by the local interplay between turbulent, convective and radiative processes; (2) how these processes interact with their surrounding environment and are influenced by mesoscale organization. Our synthesis of studies that have explored these aspects suggests that the large diversity of model responses is related to fundamental differences in how the processes controlling trade cumulus operate in models, notably, whether they are parameterized or resolved. In models with parameterized convection, cloudiness near cloud-base is very sensitive to the vigor of convective mixing in response to changes in environmental conditions. This is in contrast with results from high-resolution models, which suggest that cloudiness near cloud-base is nearly invariant with warming and independent of large-scale environmental changes. Uncertainties are difficult to narrow using current observations, as the trade cumulus variability and its relation to large-scale environmental factors strongly depend on the time and/or spatial scales at which the mechanisms are evaluated. New opportunities for testing physical understanding of the factors controlling shallow cumulus cloud responses using

  11. Cumulus Cell Transcripts Transit to the Bovine Oocyte in Preparation for Maturation.

    PubMed

    Macaulay, Angus D; Gilbert, Isabelle; Scantland, Sara; Fournier, Eric; Ashkar, Fazl; Bastien, Alexandre; Saadi, Habib A Shojaei; Gagné, Dominic; Sirard, Marc-André; Khandjian, Édouard W; Richard, François J; Hyttel, Poul; Robert, Claude

    2016-01-01

    So far, the characteristics of a good quality egg have been elusive, similar to the nature of the physiological, cellular, and molecular cues leading to its production both in vivo and in vitro. Current understanding highlights a strong and complex interdependence between the follicular cells and the gamete. Secreted factors induce cellular responses in the follicular cells, and direct exchange of small molecules from the cumulus cells to the oocyte through gap junctions controls meiotic arrest. Studying the interconnection between the cumulus cells and the oocyte, we previously demonstrated that the somatic cells also contribute transcripts to the gamete. Here, we show that these transcripts can be visualized moving down the transzonal projections (TZPs) to the oocyte, and that a time course analysis revealed progressive RNA accumulation in the TZPs, indicating that RNA transfer occurs before the initiation of meiosis resumption under a timetable fitting with the acquisition of developmental competence. A comparison of the identity of the nascent transcripts trafficking in the TZPs, with those in the oocyte increasing in abundance during maturation, and that are present on the oocyte's polyribosomes, revealed transcripts common to all three fractions, suggesting the use of transferred transcripts for translation. Furthermore, the removal of potential RNA trafficking by stripping the cumulus cells caused a significant reduction in maturation rates, indicating the need for the cumulus cell RNA transfer to the oocyte. These results offer a new perspective to the determinants of oocyte quality and female fertility, as well as provide insight that may eventually be used to improve in vitro maturation conditions. © 2016 by the Society for the Study of Reproduction, Inc.

  12. Cumulus Cell Transcripts Transit to the Bovine Oocyte in Preparation for Maturation1

    PubMed Central

    Macaulay, Angus D.; Gilbert, Isabelle; Scantland, Sara; Fournier, Eric; Ashkar, Fazl; Bastien, Alexandre; Saadi, Habib A. Shojaei; Gagné, Dominic; Sirard, Marc-André; Khandjian, Édouard W.; Richard, François J.; Hyttel, Poul; Robert, Claude

    2015-01-01

    So far, the characteristics of a good quality egg have been elusive, similar to the nature of the physiological, cellular, and molecular cues leading to its production both in vivo and in vitro. Current understanding highlights a strong and complex interdependence between the follicular cells and the gamete. Secreted factors induce cellular responses in the follicular cells, and direct exchange of small molecules from the cumulus cells to the oocyte through gap junctions controls meiotic arrest. Studying the interconnection between the cumulus cells and the oocyte, we previously demonstrated that the somatic cells also contribute transcripts to the gamete. Here, we show that these transcripts can be visualized moving down the transzonal projections (TZPs) to the oocyte, and that a time course analysis revealed progressive RNA accumulation in the TZPs, indicating that RNA transfer occurs before the initiation of meiosis resumption under a timetable fitting with the acquisition of developmental competence. A comparison of the identity of the nascent transcripts trafficking in the TZPs, with those in the oocyte increasing in abundance during maturation, and that are present on the oocyte's polyribosomes, revealed transcripts common to all three fractions, suggesting the use of transferred transcripts for translation. Furthermore, the removal of potential RNA trafficking by stripping the cumulus cells caused a significant reduction in maturation rates, indicating the need for the cumulus cell RNA transfer to the oocyte. These results offer a new perspective to the determinants of oocyte quality and female fertility, as well as provide insight that may eventually be used to improve in vitro maturation conditions. PMID:26586844

  13. Transition Metal Chelator Induces Progesterone Production in Mouse Cumulus-Oocyte Complexes and Corpora Lutea.

    PubMed

    Tian, X; Anthony, K; Diaz, Francisco J

    2017-04-01

    Progesterone production is upregulated in granulosa cells (cumulus and mural) after the LH surge, but the intra-follicular mechanisms regulating this transition are not completely known. Recent findings show that the transition metal chelator, N,N,N',N'-tetrakis-(2-pyridylmethyl)-ethylenediamine (TPEN), impairs ovarian function. In this study, we provide evidence that chelating transition metals, including zinc, enhances progesterone production. The findings show that TPEN (transition metal chelator) increases abundance of Cyp11a1 and Star messenger RNA (mRNA) between 8- and 20-fold and progesterone production more than 3-fold in cultured cumulus-oocyte complexes (COC). Feeding a zinc-deficient diet for 10 days, but not 3 days, increased Star, Hsd3b, and prostaglandin F2 alpha receptor (Ptgfr) mRNA ~2.5-fold, suggesting that the effect of TPEN is through modulation of zinc availability. Progesterone from cumulus cells promotes oocyte developmental potential. Blocking progesterone production with epostane during maturation reduced subsequent blastocyst formation from 89 % in control to 18 % in epostane-treated complexes, but supplementation with progesterone restored blastocyst developmental potential to 94 %. Feeding a zinc-deficient diet for 5 days before ovulation did not affect the number of CL, STAR protein, or serum progesterone. However, incubating luteal tissue with TPEN increased abundance of Star, Hsd3b, and Ptgfr mRNA 2-3-fold and increased progesterone production 3-fold. TPEN is known to abolish SMAD2/3 signaling in cumulus cells. However, treatment of COC with the SMAD2/3 phosphorylation inhibitor, SB421542, did not by itself induce steroidogenic transcripts but did potentiate EGF-induced Star mRNA expression. Collectively, the results show that depletion of transition metals with TPEN acutely enhances progesterone biosynthesis in COC and luteal tissue.

  14. The effects of roscovitine on cumulus cell apoptosis and the developmental competence of domestic cat oocytes.

    PubMed

    Sananmuang, T; Techakumphu, M; Tharasanit, T

    2010-01-15

    The developmental competence of cat oocytes matured in vitro is relatively poor when compared with that of in vivo oocytes. The study aimed to investigate the effect of roscovitine on the developmental competence of cat Felis catus oocytes matured in vitro. Cumulus-oocyte complexes (COCs) were classified as Grade I and II to III. Groups of COCs were cultured in 0, 12.5, 25, 50, 100, and 200 microM roscovitine for 24h and were either fixed to assess the stages of nuclear maturation (Experiment 1) or additionally matured in vitro for 24h before fixation (Experiment 2). In Experiment 3, cumulus cells from the COCs treated with roscovitine were examined for apoptosis. Experiment 4 examined the developmental competence of cat oocytes after roscovitine treatment and in vitro fertilization in terms of cleavage and morula and blastocyst formation rates. Roscovitine reversibly arrested cat oocytes at an immature stage in a dose-dependent manner. Roscovitine at 12.5 and 25 microM demonstrated less efficiency compared with that of other doses. However, higher doses of roscovitine induced cumulus cell apoptosis and resulted in a high number of degenerated oocytes after in vitro maturation. Roscovitine at 12.5 and 25 microM were therefore used to evaluate their effect on embryo development. Pretreatment with 12.5 and 25 microM roscovitine prior to in vitro maturation decreased the developmental competence of cat oocytes compared with that of non-roscovitine-treated controls. In conclusion, roscovitine reversibly maintained cat oocytes at the germinal vesicle stage without detrimental effect on nuclear maturation. However, it negatively affected cumulus cell viability and developmental competence.

  15. Relationship between apoptosis and survival molecules in human cumulus cells as markers of oocyte competence.

    PubMed

    Bosco, Liana; Chiarelli, Roberto; Roccheri, Maria Carmela; Matranga, Domenica; Ruvolo, Giovanni

    2017-08-08

    To select from a single patient the best oocytes able to reach the blastocyst stage, we searched for valuable markers for oocytes competence. We evaluated the DNA fragmentation index (DFI) and the level of some survival molecules, such as AKT, pAKT and pERK1/2, in individual cumulus cell-oocyte complexes (COC). The study included normo-responder women. The average age of the patients was 34.3. DFI in cumulus cells was evaluated using the terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labelling (TUNEL) assay in situ. AKT, pAKT and pERK1/2 were measured by immunological assay and densitometric analysis of fluorescent signals using NIS-Elements BR 3.10 image software. Statistical analysis was performed using STATA SE/14.1. The study focused on 53 patients involved after informed consent. Out of 255 MII oocytes, 197 were fertilized and the derived embryos had the following evolution: 117 completed the development to blastocyst and were transferred to uterus; 57 were vitrified at the blastocyst stage; and 23 were arrested during in vitro culture at different stages of cleavage. We found a significant statistical difference between the DFI of cumulus cells of the arrested embryos and the transferred blastocysts (P = 0.004), confirming that DFI could be considered as a valuable marker of oocyte competence. In addition, the pAKT/DFI ratio was higher in cumulus cells of oocytes able to produce blastocysts, indicating that DFI is significantly lower when pAKT is higher (P = 0.043). This study demonstrates for the first time that the relationship between apoptosis and survival molecules can be used as a marker to select the best oocytes.

  16. Can in situ measurements be used to estimate the age of shallow cumulus clouds?

    NASA Astrophysics Data System (ADS)

    Witte, M.; Chuang, P. Y.

    2010-12-01

    Cumulus clouds exhibit a life cycle that consists of: a) the growth phase (increasing size, most notably in the vertical direction); b) mature phase (growth no longer occurs; any precipitation that develops is strongest during this period); and c) dissipation phase (cloud dissipates because of precipitation and/or entrainment; no more dynamical support). Radar can track clouds over time and give some sense of the age of each cloud, but most aircraft measurements are without a temporal context. If it is possible, determining the cloud age (even if it is approximate, i.e. determining the phase in its life cycle) based solely on in situ measurements could provide important context information. The existence of such a measure would be a useful tool for interpreting past and future in situ cloud measurements. We use LES model simulations of trade wind cumulus cloud fields from one case during the Barbados Oceanographic and Meteorological Experiment (BOMEX) to test several potential cumulus cloud “clocks.” One key metric is the in-cloud buoyancy perturbation from the clear air mean as a function of time, as measured by virtual potential temperature. In general, the mean buoyancy of a cloud initially increases from zero with time, peaks, and decreases to become negatively buoyant during the latter third of its life cycle, with the amplitude of buoyancy dependent on cloud size. In some cases (more commonly for larger clouds), multiple pulses of buoyancy occur, which complicate any potential cumulus clock (as also reported by Heus et al., 2009). Since the buoyancy perturbation is not single-valued over the life of a given cloud, nor is the magnitude of the perturbation sufficient to differentiate between a mature small cloud or a growing larger cloud, other parameters must be used in addition to cloud buoyancy to construct a useful in situ cloud clock.

  17. Ionic currents activated via purinergic receptors in the cumulus cell-enclosed mouse oocyte.

    PubMed

    Arellano, Rogelio O; Martínez-Torres, Ataulfo; Garay, Edith

    2002-09-01

    Several chemical signals synthesized in the ovary, including neurotransmitters, have been proposed to serve as regulators of folliculogenesis, however, their mechanisms of action have not been completely elucidated. Here, electrophysiological and molecular biology techniques were used to study responses generated via purinergic stimulation in cultured mouse cumulus cell-enclosed oocytes (CEOs). Application of extracellular ATP elicited depolarizing responses in CEOs. Using the voltage clamp technique by impaling oocytes with two microelectrodes, we determined that these responses were mainly due to activation of two distinct ionic currents. The first corresponded to the opening of Ca2+-dependent Cl- channels (I(Cl(Ca))) and the second to the opening of Ca2+-independent channels that are permeable to Na+ (I(c+)). The potency order for different nucleotides (50 micro M) was UTP > ATP > 2meS-ATP > ADP, and alpha,betame-ATP and adenosine were found to be inactive. Suramin (100 micro M) blocked the response elicited by ATP or UTP. In addition, voltage dependent K+ currents activated by depolarization of CEOs were characterized. All CEO ionic currents recorded from the oocyte were completely inhibited by octanol (1 mM), a gap junction blocker. Thus, purinergic responses and K+ currents originate mainly in the membrane of cumulus cells. Transcripts of the purinergic receptor P2Y2 subtype were amplified by polymerase chain reaction from the cDNA of granulosa cells or cumulus cells. This study shows that P2Y2 receptors are expressed in CEOs, and that their stimulation opens at least two different types of ion channels. Both the ion channels and the receptors seemed to be located in the cumulus cells, which transmit their corresponding electrical signals to the oocyte via gap junction channels.

  18. A protective role of cumulus cells after short-term exposure of rat cumulus cell-oocyte complexes to lifestyle or environmental contaminants.

    PubMed

    Campen, Kelly A; McNatty, Kenneth P; Pitman, Janet L

    2017-04-01

    Ovarian follicular fluid provides a potential reservoir for exogenous compounds that may adversely affect oocyte quality. This study examined the effects of common lifestyle and environmental contaminants, namely bisphenol-A (BPA), caffeine, 3,4-methylenedioxymethamphetamine (MDMA), nicotine and Δ(9)-tetrahydrocannabinol (THC) on gap junction genes (Gja1, Gja4) and proteins (GJA1), glucose metabolism genes (Gfpt1, Pfkp) and oocyte growth factor genes (Bmp15, Gdf9), as well as gap junction transfer rate, in rat cumulus-oocyte complexes (COCs). In vitro exposure to MDMA and THC accelerated the timing of meiotic resumption and all contaminants altered either gap junction gene expression (BPA, caffeine, MDMA and THC) or transfer rate (BPA and nicotine). In vitro exposure of COCs to MDMA also altered glucose metabolism genes. Overall, oocyte-derived genes were largely unaffected following exposure to any contaminant. In summary, the impact of short-term exposure to lifestyle and environmental contaminants on oocyte function may be diminished due to protective properties of cumulus cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Statistical analysis of an LES shallow cumulus cloud ensemble using a cloud tracking algorithm

    NASA Astrophysics Data System (ADS)

    Dawe, J. T.; Austin, P. H.

    2012-01-01

    A technique for the tracking of individual clouds in a Large Eddy Simulation (LES) is presented. We use this technique on an LES of a shallow cumulus cloud field based upon the Barbados Oceanographic and Meteorological Experiment (BOMEX) to calculate statistics of cloud height, lifetime, and other physical properties for individual clouds in the model. We also examine the question of nature versus nurture in shallow cumulus clouds: do properties at cloud base determine the upper-level properties of the clouds (nature), or are cloud properties determined by the environmental conditions they encounter (nurture). We find that clouds which ascend through an environment that has been pre-moistened by previous cloud activity are no more likely to reach the inversion than clouds that ascend through a drier environment. Cloud base thermodynamic properties are uncorrelated with upper-level cloud properties, while mean fractional entrainment and detrainment rates display moderate correlations with cloud properties up to the inversion. Conversely, cloud base area correlates well with upper-level cloud area and maximum cloud height. We conclude that cloud thermodynamic properties are primarily influenced by entrainment and detrainment processes, cloud area and height are primarily influenced by cloud base area, and thus nature and nurture both play roles in the dynamics of BOMEX shallow cumulus clouds.

  20. Statistical analysis of a LES shallow cumulus cloud ensemble using a cloud tracking algorithm

    NASA Astrophysics Data System (ADS)

    Dawe, J. T.; Austin, P. H.

    2011-08-01

    A technique for the tracking of individual clouds in a Large Eddy Simulation (LES) is presented. We use this technique on a LES of a shallow cumulus cloud field based upon the Barbados Oceanographic and Meteorological Experiment (BOMEX) to calculate statistics of cloud height, lifetime, and other physical properties for individual clouds in the model. We also examine the question of nature versus nurture in shallow cumulus clouds: do properties at cloud base determine the upper-level properties of the clouds (nature), or are cloud properties determined by the environmental conditions they encounter (nurture). We find that clouds which ascend through an environment that has been pre-moistened by previous cloud activity are no more likely to reach the inversion than clouds that ascend through a drier environment. Cloud base thermodynamic properties are uncorrelated with upper-level cloud properties, while mean fractional entrainment and detrainment rate displays moderate correlations with cloud properties up to the inversion. Conversely, cloud base area correlates well with upper-level cloud area and maximum cloud height. We conclude that cloud thermodynamic properties are primarily influenced by entrainment and detrainment processes, cloud area and height are primarily influenced by cloud base area, and thus nature and nurture both play roles in the dynamics of BOMEX shallow cumulus clouds.

  1. Daidzein does affect progesterone secretion by pig cumulus cells but it does not impair oocytes IVM.

    PubMed

    Galeati, Giovanna; Vallorani, Claudia; Bucci, Diego; Bernardini, Chiara; Tamanini, Carlo; Parmeggiani, Albamaria; Spinaci, Marcella

    2010-08-01

    Daidzein, an isoflavone abundant in soybeans and other legumes, displays estrogen like properties. This study was aimed at evaluating the effect of daidzein (1 and 10 microM) on nuclear and cytoplasmic maturation of pig oocytes and on steroidogenic activity of cumulus cells. Daidzein supplementation during IVM had no effect on nuclear maturation and on fertilization traits. By contrast, both concentrations significantly (P < 0.05) inhibited progesterone production by cumulus cells after 24 and 48 h of culture while they did not induce any effect on estradiol production. Furthermore, daidzein did not exert any effect on the percentage of embryos that developed to blastocyst stage, on the number of blastomeres per blastocyst, or on the level of Hsp-70 and -90 gene transcript. Overall, our data demonstrate that daidzein added during oocyte maturation does not affect pig embryo development even if it markedly inhibits progesterone production by cumulus cells. Further studies are needed to evaluate the possible effect of daidzein during embryonic development.

  2. Repeated superovulation may affect mitochondrial functions of cumulus cells in mice

    PubMed Central

    Xie, Juan-Ke; Wang, Qian; Zhang, Ting-Ting; Yin, Shen; Zhang, Cui-Lian; Ge, Zhao-Jia

    2016-01-01

    Controlled ovarian stimulation by exogenous gonadotrophins is a key procedure during the in vitro fertilization cycle to obtain a sufficient number of oocytes in humans. Previous studies demonstrated that repeated superovulation had deleterious effects on the ovaries. However, whether repeated superovulation adversely affects the mitochondrial functions of cumulus cells remains unclear. In this study, mice were divided into three groups: superovulation once (R1); superovulation three times (R3), and superovulation five times (R5). We evaluated the effects of repeated superovulation on mitochondrial DNA copies (mtDNA) and observed decreased mtDNA copies per cell with increasing number of superovulation cycles. Further, we investigated the DNA methylation status in exon 2 and the mRNA expression level of nuclear-encoded DNA polymerase gamma A (PolgA). The results showed that the DNA methylation levels of PolgA in R1 and R5 were slightly lower than in R3. Additionally, the altered DNA methylation in PolgA coincided with the changes in PolgA expression in cumulus cells. We also found that the mRNA expression of COX1, CYTB, ND2, and ND4 was altered by repeated superovulation in cumulus cells. Thus, repeated superovulation had adverse effects on mitochondrial function. PMID:27698360

  3. Repeated superovulation may affect mitochondrial functions of cumulus cells in mice.

    PubMed

    Xie, Juan-Ke; Wang, Qian; Zhang, Ting-Ting; Yin, Shen; Zhang, Cui-Lian; Ge, Zhao-Jia

    2016-10-04

    Controlled ovarian stimulation by exogenous gonadotrophins is a key procedure during the in vitro fertilization cycle to obtain a sufficient number of oocytes in humans. Previous studies demonstrated that repeated superovulation had deleterious effects on the ovaries. However, whether repeated superovulation adversely affects the mitochondrial functions of cumulus cells remains unclear. In this study, mice were divided into three groups: superovulation once (R1); superovulation three times (R3), and superovulation five times (R5). We evaluated the effects of repeated superovulation on mitochondrial DNA copies (mtDNA) and observed decreased mtDNA copies per cell with increasing number of superovulation cycles. Further, we investigated the DNA methylation status in exon 2 and the mRNA expression level of nuclear-encoded DNA polymerase gamma A (PolgA). The results showed that the DNA methylation levels of PolgA in R1 and R5 were slightly lower than in R3. Additionally, the altered DNA methylation in PolgA coincided with the changes in PolgA expression in cumulus cells. We also found that the mRNA expression of COX1, CYTB, ND2, and ND4 was altered by repeated superovulation in cumulus cells. Thus, repeated superovulation had adverse effects on mitochondrial function.

  4. [Biomarkers of the cumulus cells in medically assisted procreation: State-of-the-art].

    PubMed

    Pourret, E; Hamamah, S; Aït-Ahmed, O

    2016-11-01

    The oocyte grows within a follicle composed of layers of somatic cells. It undergoes with the cumulus cells that form the innermost layer a dialogue that is critical for its maturation. Based on the assumption that the transcriptome of the cumulus cells reflects the physiology of the oocyte, it may prove a useful non-invasive tool in embryo selection to improve assisted reproduction outcomes. During the past decade, various studies have been conducted with the objective of identifying cumulus biomarker genes as prognosis tools for oocyte quality and competence. Remarkably no common biomarkers stand out among all these studies. In this review we perform a critical analysis of the literature in order to reveal some of the parameters that may account for these discrepancies, such as patients' inclusion criteria (maternal age, stimulation protocols), day of embryo transfer (day 3 or 5), outcome criteria (oocyte potential, embryo competence, pregnancy). Moreover there is a lack of standardization in the experimental designs used for RNA extraction and gene expression assessment (microarrays, RT-qPCR) and for the statistical analyses. In conclusion, critical analyses such as the present one are indispensable to pave the way for future searches of predictive biomarkers of pregnancy.

  5. Direct entrainment and detrainment rate distributions of individual shallow cumulus clouds in an LES

    NASA Astrophysics Data System (ADS)

    Dawe, J. T.; Austin, P. H.

    2013-08-01

    Probability distribution functions of shallow cumulus cloud core entrainment and detrainment rates are calculated using 4362 individual cumulus clouds isolated from LES (large eddy simulation) using a cloud tracking algorithm. Calculation of the mutual information between fractional entrainment/detrainment and a variety of mean cloud core properties suggests that fractional entrainment rate is best predicted by the mean cloud buoyancy B and the environmental buoyancy lapse rate dθρ/dz at that level, while fractional detrainment is best predicted by the mean vertical velocity w and the critical mixing fraction χc. Fractional entrainment and detrainment rates are relatively insensitive to cloud core horizontal area, and the perimeter of horizontal cloud core sections display an a0.73 dependence. This implies that cloud core mass entrainment flux E is proportional to cloud core cross-sectional area instead of cloud core surface area, as is generally assumed. Empirical best-fit relations for ɛ(B, dθρ/dz and δ(w, χc) are found for both individual shallow cumulus clouds and cloud ensembles. It is found that clouds with high buoyancy in strong stratification experience low entrainment rates, while clouds with high vertical velocities and critical mixing fractions experience low detrainment rates.

  6. Observed Lagrangian Transition of Stratocumulus into Cumulus during ASTEX: Mean State and Turbulence Structure.

    NASA Astrophysics Data System (ADS)

    de Roode, Stephan R.; Duynkerke, Peter G.

    1997-09-01

    Aircraft measurements made during the `First Lagrangian' of the Atlantic Stratocumulus Transition Experiment (ASTEX) between 12 and 14 June 1992 are presented. During this Lagrangian experiment an air mass was followed that was advected southward by the mean wind. Five aircraft flights were undertaken to observe the transition of a stratocumulus cloud deck to thin and broken stratocumulus clouds penetrated by cumulus from below. From the horizontal aircraft legs the boundary layer mean structure, microphysics, turbulence structure, and entrainment were analyzed. The vertical profiles of the vertical velocity skewness are shown to illustrate the transition of a cloudy boundary layer predominantly driven by longwave radiative cooling at the cloud top to one driven mainly by convection due to an unstable surface stratification and cumulus clouds. During the last flight before the stratocumulus deck was observed to be broken and replaced by cumuli, the total water flux, the virtual potential temperature flux, and the vertical velocity variance in the stratocumulus cloud layer were found significantly larger compared with the previous flights. To analyze the cloud-top stability the mean jumps of conserved variables across the inversion were determined from porpoising runs through the cloud top. These jumps were compared with cloud-top entrainment instability criteria discussed in the literature. It is suggested that enhanced entrainment of dry air is a key mechanism in the stratocumulus-cumulus transition.

  7. Role of PTGS2-generated PGE2 during gonadotrophin-induced bovine oocyte maturation and cumulus cell expansion.

    PubMed

    Marei, Waleed F; Abayasekara, D Robert E; Wathes, D Claire; Fouladi-Nashta, Ali A

    2014-03-01

    Prostaglandin E2 (PGE2) is an autocrine/paracrine factor which mediates gonadotrophin (Gn) stimulation of cumulus expansion and oocyte maturation in rodents. Its role in bovine oocyte maturation is less characterized. This study detected PTGS2 (COX2) and PGE synthases (PTGES1, PTGES2 and PTGES3) in bovine cumulus-oocyte complexes (COC). Only PTGS2 and PTGES1 expression changed during maturation. In Gn-free media, no cumulus expansion and ∼45% nuclear maturation was achieved, while Gn-induced maturation showed full cumulus expansion (score 3) and ∼87% maturation. PGE2 supplementation without Gn induced mild cumulus expansion (score 0.5-1) but increased nuclear maturation to levels similar to those obtained with Gn alone. In the presence of Gn, exogenous PGE2 did not affect expansion or nuclear maturation and subsequent embryo development. Treatment with PTGS2 selective inhibitor (NS398), PTGS2-specific siRNA or PTGER2-receptor antagonist (AH6809) resulted in ∼20-25% reduction in nuclear maturation. NS398 and AH6809 did not affect cumulus expansion. Most oocytes not reaching metaphase of second meiosis (MII) following NS398, AH6809 and PTGS2-specific siRNA treatments were at MI. After longer maturation, NS398-treated oocytes had normal MII rate and uncompromised embryo development. PGE2 has a limited role in cumulus expansion in bovine COC but is important for the timing of Gn-induced nuclear maturation. We confirmed that genes involved in the synthesis of prostaglandin E2 (PGE2) are expressed by cumulus-oocyte complexes (or eggs) of cows and that PGE2 is synthesized during oocyte maturation in the presence of gonadotrophin hormones. When we inhibited synthesis of PGE2 or blocked its receptors, oocyte maturation, but not cumulus expansion, was compromised. Further investigation showed that oocyte maturation is delayed but not arrested when PGE2 synthesis is inhibited. On the other hand, addition of exogenous PGE2 induced a high maturation rate and mild cumulus

  8. NASA Studies Lightning Storms Using High-Flying, Uninhabited Vehicle

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely-piloted aircraft to study thunderstorms in the Atlantic Ocean off Key West and the west of the Everglades. Data obtained through sensors mounted to the aircraft will allow researchers in ACES to gauge elements such as lightning activity and the electrical environment in and around storms. By learning more about individual storms, scientists hope to better understand the global water and energy cycle, as well as climate variability. Contained in one portion of the aircraft is a three-axis magnetic search coil, which measures the AC magnetic field; a three-axis electric field change sensor; an accelerometer; and a three-axis magnetometer, which measures the DC magnetic field. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the Marshall Space Flight Center, the University of Alabama in Huntsville, NASA's Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

  9. The Upward Directed Poynting Flux over a Thunderstorm

    NASA Astrophysics Data System (ADS)

    Farrell, W. M.; Goldberg, R. A.; Blakeslee, R. J.; Cummer, S. A.; Deschj, M. D.; Mach, D. M.; Mitchell, J. D.; Croskey, C. L.

    2003-12-01

    In August of 2002, NASA carried out the Altus Cumulus Electrification Study (ACES) to investigate the lightning/storm relationship, to quantify the storm electrical budget, and to validate the TRMM lightning sensor (LIS) data. The platform was General Atomic's Altus uninhabited aerial vehicle (UAV) which allowed long-duration, close-proximity monitoring of storms from their births to deaths. The platform carried a set of DC Field Mill sensors to measure electrostatic fields, AC electric and magnetic field sensors for deriving the Poynting flux, a Gerdien conductivity probe, optical sensors, and a flight payload data system. The data system collected low rate data, and also cloud be event-triggered into high rate mode for approximately 0.3 seconds about lightning strikes. During the month long mission, 11 scientific flights occurred yielding over 4300 high rate triggered events. An objective of this study was to determine the amount of upward radiated power into the middle atmosphere and ionosphere, and determine contribution of the radiated power to the global atmospheric electric circuit. In this work, we show upward Poynting flux measurements between 10 Hz -100 kHz from some specific thunderstorm overflights. We find that upward radiated powers from lightning strikes can be large. However, displacement currents are also comparatively large, suggesting that the radiation impedance above a thunderstorm is relatively low (~150 Ohms at 10 kHz). This radiation impedence is calculated as a function of frequency. The effect of the radiated power on the global circuit will be discussed.

  10. Earth Science

    NASA Image and Video Library

    2002-08-01

    A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely-piloted aircraft to study thunderstorms in the Atlantic Ocean off Key West and the west of the Everglades. Data obtained through sensors mounted to the aircraft will allow researchers in ACES to gauge elements such as lightning activity and the electrical environment in and around storms. By learning more about individual storms, scientists hope to better understand the global water and energy cycle, as well as climate variability. Contained in one portion of the aircraft is a three-axis magnetic search coil, which measures the AC magnetic field; a three-axis electric field change sensor; an accelerometer; and a three-axis magnetometer, which measures the DC magnetic field. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the Marshall Space Flight Center, the University of Alabama in Huntsville, NASA's Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

  11. Earth Science

    NASA Image and Video Library

    2001-01-01

    A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Radio news media can talk with Dr. Richard Blakeslee, the project's principal investigator, and Tony Kim, project manager at the Marshall Space Flight Center (MSFC), about their results and how their work will help improve future weather forecasting ability. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely- piloted aircraft to study a thunderstorm in the Atlantic Ocean off Key West, two storms at the western edge of the Everglades, and a large storm over the northwestern corner of the Everglades. This photograph shows Tony Kim And Dr. Richard Blakeslee of MSFC testing aircraft sensors that would be used to measure the electric fields produced by thunderstorm as part of NASA's ACES. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the MSFC, the University of Alabama in Huntsville, NASA's Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

  12. Cloud Condensation Nuclei in Cumulus Humilis — selected Case Study During the CHAPS Campaign

    SciTech Connect

    Yu, X.; Lee, Y.; Berg, L.; Berkowitz, C.; Alexander, L.; Laskin, A.; Ogren, J.; Andrews, E.

    2010-03-15

    The Cumulus Humilis Aerosol Processing Study (CHAPS) provided a unique opportunity to study aerosol and cloud processing. Clouds play an active role in the processing and cycling of atmospheric constituents. Gases and particles can partition to cloud droplets by absorption and condensation as well as activation and impact scavenging. The U.S. Department of Energy (DOE) G-1 aircraft was used as one of the main platforms in CHAPS. Flight tracks were designed and implemented to characterize freshly emitted aerosols at cloud top and cloud base as well as within the cloud, i.e., cumulus humilis (or fair-weather cumulus), in the vicinity of Oklahoma City. Measurements of interstitial aerosols and residuals of activated condensation cloud nuclei were conducted simultaneously. The interstitial aerosols were measured downstream of an isokinetic inlet, and the activated particles downstream of a counter-flow virtual impactor (CVI). The sampling line to the Aerodyne Aerosol Mass Spectrometer (AMS) was switched between the isokinetic inlet and the CVI to allow characterization of non-activated interstitial particles outside of clouds in contrast to particles activated in clouds. Trace gases including ozone, carbon monoxide, sulfur dioxide, and a series of volatile organic compounds (VOCs) were also measured, as were key meteorological state parameters including liquid water content, cloud drop size, and dew point. We will report on the CCN properties in cumulus humilis. Several approaches will be taken. The first is single-particle analysis of particles collected by the Time-Resolved Aerosol Sampler (TRAC) by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled with energy disperse X-ray spectroscopy (EDX). Specifically, we examine differences between activated and interstitial ones, such as differences in chemical composition and morphology. The second analysis will link in situ measurements by AMS and PTRMS with the observations by TRAC. For

  13. Cloud Condensation Nuclei in Cumulus Humilis - Selected Case Study During the CHAPS Campaign

    NASA Astrophysics Data System (ADS)

    Yu, X.; Berg, L. K.; Berkowitz, C. M.; Alexander, M. L.; Lee, Y.; Laskin, A.; Ogren, J. A.; Andrews, B.

    2009-12-01

    The Cumulus Humilis Aerosol Processing Study (CHAPS) provided a unique opportunity to study aerosol and cloud processing. Clouds play an active role in the processing and cycling of atmospheric constituents. Gases and particles can partition to cloud droplets by absorption and condensation as well as activation and pact scavenging. The Department of Energy (DOE) G-1 aircraft was used as one of the main platforms in CHAPS. Flight tracks were designed and implemented to characterize freshly emitted aerosols on cloud top and cloud base as well as with cloud, i.e., cumulus humilis (or fair-weather cumulus), in the vicinity of Oklahoma City. Measurements of interstitial aerosols and residuals of activated condensation cloud nuclei were conducted simultaneously. The interstitial aerosols were determined downstream of an isokinetic inlet; and the activated particles downstream of a counter-flow virtual impactor (CVI). The sampling line to the Aerodyne Aerosol Mass Spectrometer was switched between the isokinetic inlet and the CVI to allow characterization of interstitial particles out of clouds in contrast to particles activated in clouds. Trace gases including ozone, carbon monoxide, sulfur dioxide, and a series of volatile organic compounds (VOCs) were also measured as were key meteorological state parameters including liquid water content, cloud drop size, and dew point temperature were measured. This work will focus on studying CCN properties in cumulus humilis. Several approaches will be taken. The first is single particle analysis of particles collected by the Time-Resolved Aerosol Sampler (TRAC) by SEM/TEM coupled with EDX. We will specifically look into differences in particle properties such as chemical composition and morphology between activated and interstitial ones. The second analysis will link in situ measurements with the snap shots observations by TRAC. For instance, by looking into the characteristic m/z obtained by AMS vs. CO or isoprene, one can gain

  14. Solar modulation of atmospheric electrification through variation of the conductivity over thunderstorms

    NASA Technical Reports Server (NTRS)

    Markson, R.

    1974-01-01

    Variations of the current in the global atmospheric electrical circuit can be produced through regulation of the resistance between the tops of thunderclouds and the ionosphere. Long-and short-term changes in the conductivity of this region occur due to changes in the ionization rate resulting from solar activity. Previous suggestions that the phenomena might be due to conductivity variations in the fair weather part of the world or an influx of space charge to the upper atmosphere are considered unlikely. It might be possible to test the proposed mechanism by measuring the temporal variation of the ionospheric potential during disturbed solar periods. Another approach would be to measure simultaneously the variation in ionization rate and electric current over thunder-storms. Several ways in which changes in atmospheric electrification might influence other meteorological phenomena are mentioned.

  15. “Capacitive Sensor” to Measure Flow Electrification and Prevent Electrostatic Hazards

    PubMed Central

    Paillat, Thierry; Touchard, Gerard; Bertrand, Yves

    2012-01-01

    At a solid/liquid interface, physico-chemical phenomena occur that lead to the separation of electrical charges, establishing a zone called electrical double layer. The convection of one part of these charges by the liquid flow is the cause of the flow electrification phenomenon which is suspected of being responsible of incidents in the industry. The P' Institute of Poitiers University and CNRS has developed an original sensor called “capacitive sensor” that allows the characterization of the mechanisms involved in the generation, accumulation and transfer of charges. As an example, this sensor included in the design of high power transformers, could easily show the evolution of electrostatic charge generation developed during the operating time of the transformer and, therefore, point out the operations leading to electrostatic hazards and, then, monitor the transformer to prevent such risks. PMID:23202162

  16. “Capacitive sensor” to measure flow electrification and prevent electrostatic hazards.

    PubMed

    Paillat, Thierry; Touchard, Gerard; Bertrand, Yves

    2012-10-25

    At a solid/liquid interface, physico-chemical phenomena occur that lead to the separation of electrical charges, establishing a zone called electrical double layer. The convection of one part of these charges by the liquid flow is the cause of the flow electrification phenomenon which is suspected of being responsible of incidents in the industry. The P’ Institute of Poitiers University and CNRS has developed an original sensor called “capacitive sensor” that allows the characterization of the mechanisms involved in the generation, accumulation and transfer of charges. As an example, this sensor included in the design of high power transformers, could easily show the evolution of electrostatic charge generation developed during the operating time of the transformer and, therefore, point out the operations leading to electrostatic hazards and, then, monitor the transformer to prevent such risks.

  17. Solar modulation of atmospheric electrification through variation of the conductivity over thunderstorms

    NASA Technical Reports Server (NTRS)

    Markson, R.

    1975-01-01

    It is suggested that variations of the current in the global atmospheric electrical circuit can be produced through regulation of the resistance between the tops of thunderclouds and the ionosphere. Long- and short-term changes in the conductivity of this region occur due to changes in the ionization rate resulting from solar activity. Previous suggestions that the phenomena might be due to conductivity variations in the fair weather part of the world or an influx of space charge to the upper atmosphere are discussed and considered unlikely. It might be possible to test the proposed mechanism by measuring the temporal variation of the ionospheric potential during distributed solar periods. Another approach would be to measure simultaneously the variation in ionization rate and electric current over thunderstorms. Several ways in which changes in atmospheric electrification might influence other meteorological phenomena are mentioned.

  18. Theoretical modeling of relative humidity on contact electrification of sand particles

    PubMed Central

    Zheng, XiaoJing; Zhang, Rui; Huang, HaoJie

    2014-01-01

    Contact electrification of identical insulating particles has crucial significance for industrial and environmental science, especially in wind-blown granular systems. At the same time, the experimental phenomena of charge transfer first increased and then decreased with the increase of relative humidity has attracted the interest of many researchers. Humidity can affect the charge transfer has been early observed in the experiment, but the reason always puzzles researchers. In this study, based on trapped high-energy electron transfer mechanism, we introduce the effect of the water film in the charge transfer model and consider the actual situations of the sand particles in the collision process. Furthermore, charge transfer between sand particles in a single collision under different humidity conditions is investigated. The predicted results agree well with the law obtained in existing experiments qualitatively and thereby a possible explanation why humidity can affect the charge transfer is given. PMID:24637964

  19. Robust thin-film generator based on segmented contact-electrification for harvesting wind energy.

    PubMed

    Meng, Xian Song; Zhu, Guang; Wang, Zhong Lin

    2014-06-11

    Collecting and converting energy from ambient air flow promise to be a viable approach in developing self-powered autonomous electronics. Here, we report an effective and robust triboelectric generator that consists of an undulating thin-film membrane and an array of segmented fine-sized electrode pairs on a single substrate. Sequential processes of contact electrification and electrostatic induction generate alternating flows of free electrons when the membrane interacts with ambient air flow. Based on an optimum rational design, the segmented electrodes play an essential role in boosting the output current, leading to an enhancement of over 500% compared to the structure without the segmentation. The thin-film based generator can simultaneously and continuously light up tens of commercial light-emitting diodes. Moreover, it possesses exceptional durability, providing constant electric output after millions of operation cycles. This work offers a truly practical solution that opens the avenue to take advantage of wind energy by using the triboelectric effect.

  20. Final environmental impact statement/report and 4(f) statement. Volume 1. Northeast corridor improvement project electrification: New Haven, CT to Boston, MA. Final report

    SciTech Connect

    1994-10-31

    This document is the final environmental impact statement and final environmental impact report (FEIS/R) on the proposal by the National Railroad Passenger Corporation (Amtrak) to complete the electrification of the Northeast Corridor main line by extending electric traction from New Haven, CT, to Boston, MA. This document (Volume I) is the main body of the FEIS/R and includes a 4(f) Statement on the proposed location of an electrification facility in the Great Swamp Wildlife Management Area.

  1. Cloud electrification and lightning activity in a tropical cyclone-like vortex

    NASA Astrophysics Data System (ADS)

    Barthe, C.; Hoarau, T.; Bovalo, C.

    2016-11-01

    In this study, a high resolution simulation of an electrified tropical cyclone-like vortex was performed with the French mesoscale model Meso-NH coupled to an explicit electrical scheme. The objective was to analyze how graupel characteristics could influence the occurrence of lightning flashes in tropical cyclones. Two simulations were run: a control simulation using a 1-moment mixed phase bulk microphysical scheme, and a second simulation in which the parameters used to describe the graupel mass-diameter and fall speed-diameter relationships were modified to obtain smaller graupel fall speeds. Decreasing the graupel fall speed (vg) resulted in a weaker storm with a larger radius of maximum winds. For both simulated tropical cyclones, a deep mixed phase layer conducive to cloud electrification was observed. However, in the simulation where vg was decreased, the flash rate was almost zero throughout the simulation, whereas it reached a few flashes per minute in the control simulation. Several reasons that can explain this difference in the total flash rate are highlighted. Decreasing vg resulted in graupel being spread horizontally over a broader area by the secondary circulation. The more pronounced tilting observed with slower vg meant that poles of charges were not vertically aligned and thus the vertical electric field was reduced. In this study, the difference in the total flash rate mainly arose from changes in the mass and charge transfer rates due to changes in the parameters used to define the mass-diameter and particle-diameter relationships. Cloud electrification and lightning flashes being threshold-processes, a small change in the model physics can have a dramatic impact on the total flash rate.

  2. Influence of manganese on apoptosis and glutathione content of cumulus cells during in vitro maturation in bovine oocytes.

    PubMed

    Anchordoquy, Juan Patricio; Anchordoquy, Juan Mateo; Picco, Sebastián J; Sirini, Matías A; Errecalde, Ana Lía; Furnus, Cecilia C

    2014-02-01

    We have investigated the effect of different Mn concentrations on (1) DNA integrity of cumulus cells by olive tail moment (OTM); (2) cumulus cells apoptosis by Annexin V staining assay; (3) intracellular total glutathione (GSH-GSSG) content; and (4) oocyte nuclear maturation and embryo cleavage after in vitro fertilisation (IVF). For this purpose, 0 (control), 2 (Mn1), 5 (Mn2) and 6 ng/mL (Mn3) Mn concentrations were added to IVM medium. Comet assay analysed by OTM was significantly higher in cumulus cells arising from COCs matured without Mn (control, P < 0.01) respect to cumulus cells obtained from COCs matured with Mn (control: 5.18 ± 2.3; Mn1: 2.93 ± 2.2; Mn2: 2.63 ± 2.4; Mn3: 2.92 ± 2.4). The frequency of apoptotic cells was higher in the control group (control: 6.63 ± 0.59; Mn1: 5.05 ± 0.5; Mn2: 4.61 ± 0.49; Mn3: 3.33 ± 0.42). Intracellular concentration of GSH-GSSG increased in oocytes and cumulus cells matured in the presence of Mn (P < 0.01). There were no differences in percentages of nuclear maturation when Mn was added to IVM medium at any concentration, but at 6 ng/mL Mn a higher cleavage rate was observed respect to the control group (P < 0.05). In conclusion, deficiency in Mn concentration during in vitro maturation increased the damage in the DNA molecule and the frequency of apoptotic cumulus cells. However, the addition of an adequate Mn concentration (6 ng/mL Mn) to IVM medium improved the health of cumulus-oocyte complexes and produced more cleaved embryos 48 h after IVF.

  3. Transportation Electrification

    SciTech Connect

    Schwendeman, Lawrence; Crouch, Alan

    2013-12-17

    This project has accomplished the following objectives: to address the critical need for technician training in new and emerging propulsion technologies by developing new courses, including information and training on electric vehicles, plug-in hybrid electric vehicles, and fuel cell vehicles; to integrate the new certificate with the existing Associate of Applied Science Degree and Certificate automotive degrees; to disseminate these leading edge courses throughout the Commonwealth of Virginia and neighboring Mid-Atlantic States; and to provide training opportunities for displaced workers and underrepresented populations seeking careers in the automotive industry.

  4. Regulation of fatty acid oxidation in mouse cumulus-oocyte complexes during maturation and modulation by PPAR agonists.

    PubMed

    Dunning, Kylie R; Anastasi, Marie R; Zhang, Voueleng J; Russell, Darryl L; Robker, Rebecca L

    2014-01-01

    Fatty acid oxidation is an important energy source for the oocyte; however, little is known about how this metabolic pathway is regulated in cumulus-oocyte complexes. Analysis of genes involved in fatty acid oxidation showed that many are regulated by the luteinizing hormone surge during in vivo maturation, including acyl-CoA synthetases, carnitine transporters, acyl-CoA dehydrogenases and acetyl-CoA transferase, but that many are dysregulated when cumulus-oocyte complexes are matured under in vitro maturation conditions using follicle stimulating hormone and epidermal growth factor. Fatty acid oxidation, measured as production of ³H₂O from [³H]palmitic acid, occurs in mouse cumulus-oocyte complexes in response to the luteinizing hormone surge but is significantly reduced in cumulus-oocyte complexes matured in vitro. Thus we sought to determine whether fatty acid oxidation in cumulus-oocyte complexes could be modulated during in vitro maturation by lipid metabolism regulators, namely peroxisome proliferator activated receptor (PPAR) agonists bezafibrate and rosiglitazone. Bezafibrate showed no effect with increasing dose, while rosiglitazone dose dependently inhibited fatty acid oxidation in cumulus-oocyte complexes during in vitro maturation. To determine the impact of rosiglitazone on oocyte developmental competence, cumulus-oocyte complexes were treated with rosiglitazone during in vitro maturation and gene expression, oocyte mitochondrial activity and embryo development following in vitro fertilization were assessed. Rosiglitazone restored Acsl1, Cpt1b and Acaa2 levels in cumulus-oocyte complexes and increased oocyte mitochondrial membrane potential yet resulted in significantly fewer embryos reaching the morula and hatching blastocyst stages. Thus fatty acid oxidation is increased in cumulus-oocyte complexes matured in vivo and deficient during in vitro maturation, a known model of poor oocyte quality. That rosiglitazone further decreased fatty acid

  5. Mitochondria and mitochondrial DNA in porcine oocytes and cumulus cells--A search for developmental competence marker.

    PubMed

    Pawlak, Piotr; Chabowska, Agnieszka; Malyszka, Natalia; Lechniak, Dorota

    2016-03-01

    The development of mammalian oocytes is dependent on bidirectional signaling with the surrounding cumulus cells. Among the numerous factors that contribute to oocyte developmental competence, the mitochondria and the mitochondrial DNA play pivotal roles. Although these highly abundant organelles have been well-studied in oocytes, their roles, abundance and metabolism remain elusive in cumulus cells. Therefore, the aim of our study was to analyze the correlation between the mtDNA copy number in cumulus cells and oocytes, as well as the mitochondrial distribution patterns in oocytes, using two groups of animals that differ in terms of the developmental competence of their oocytes. We determined a positive correlation between the mtDNA copy number in the cumulus cells and mtDNA copy number in oocytes of prepubertal pigs and negative correlation in cyclic gilts. These opposing correlations may reflect the differences in the developmental competence of the prepubertal and cyclic oocytes. We also hypothesize that observed differences may reflect different metabolism and energy requirements of the cumulus-oocyte complexes from prepubertal and cyclic gilts. The mitochondrial distribution patterns in the prepubertal and cyclic gilts were not different.

  6. Generation of rats from vitrified oocytes with surrounding cumulus cells via in vitro fertilization with cryopreserved sperm.

    PubMed

    Fujiwara, Katsuyoshi; Kamoshita, Maki; Kato, Tsubasa; Ito, Junya; Kashiwazaki, Naomi

    2017-01-01

    The objective of this study was to evaluate fertility and full-term development of rat vitrified oocytes after in vitro fertilization (IVF) with cryopreserved sperm. Oocytes with or without surrounding cumulus cells were vitrified with 30% ethylene glycol + 0.5 mol/L sucrose + 20% fetal calf serum by using the Cryotop method. The warmed oocytes were co-cultured with sperm. Although the denuded/vitrified oocytes were not fertilized, some of the oocytes vitrified with cumulus cells were fertilized (32.7%) after IVF with fresh sperm. When IVF was performed with cryopreserved sperm, vitrified or fresh oocytes with cumulus cells were fertilized (62.9% or 41.1%, respectively). In addition, to confirm the full-term development of the vitrified oocytes with surrounding cumulus cells after IVF with cryopreserved sperm, 108 vitrified oocytes with two pronuclei (2PN) were transferred into eight pseudopregnant females, and eight pups were obtained from three recipients. The present work demonstrates that vitrified rat oocytes surrounded by cumulus cells can be fertilized in vitro with cryopreserved sperm, and that 2PN embryos derived from cryopreserved gametes can develop to term. To our knowledge, this is the first report of successful generation of rat offspring derived from vitrified oocytes that were fertilized in vitro with cryopreserved sperm.

  7. cyclic GMP Mediated Inhibition of Spontaneous Germinal Vesicle Breakdown Both with and without Cumulus in Mouse Oocyte.

    PubMed

    Hwang, Heekyung; Cheon, Yong-Pil

    2016-12-01

    Intact germinal vesicle (GV) arrest and release are essential for maintaining the fertility of mammals inducing human. Intact germinal vesicle release, maturation of oocytes is maintained by very complex procedures along with folliculogenesis and is a critical step for embryonic development. Cyclic guanosine monophosphate (cGMP) has been suggested a key factor for meiotic arrest but so far its mechanisms are controversy. In this study we examine the effects of cGMP on germinal vesicle breakdown in cumulus-enclosed oocytes and denuded oocytes. Spontaneous maturation was inhibited by a cGMP agonist, 8-Br-cGMP with concentration dependent manners both in cumulus-enclosed oocytes and denuded oocytes. The inhibitory effect was more severe in denuded oocytes than cumulus-enclosed oocytes. The Rp-8-Br-cGMP and Rp-pCPT-8-Br-cGMP did not severely block GVB compared to 8-Br-cGMP. The spontaneous GVB inhibitory effects were different by the existence of cumulus. Based on them it is suggested that the cumulus modulates the role of cGMP in GV arrest.

  8. Investigation of the causes for climate model biases when simulating continental shallow cumulus clouds using a RACORO case study

    NASA Astrophysics Data System (ADS)

    Lin, W.; Vogelmann, A. M.; Fridlind, A. M.; Endo, S.; Song, H.; Toto, T.; Liu, Y.

    2013-12-01

    It is not uncommon that climatically important low-level clouds can be both underestimated and misrepresented by climate models. Simulations using the single-column Community Atmosphere Model version 5 (SCAM5) of a multi-day continental shallow cumulus cloud case over the Atmospheric Radiation Measurement (ARM) Climate Research Facility's Southern Great Plain site during the RACORO campaign exhibit these same traits, and the causes are investigated in this work. The SCAM5 simulations are driven by observationally constrained large-scale forcings. The model's shallow cumulus convection scheme, which is intended for such cloud processes, tends to significantly under-produce clouds during the time when shallow cumulus activity prevails in observations, while other physical schemes in the model have a strong tendency to misrepresent (over-trigger) the low-level clouds throughout the day. Large-eddy simulations that are driven by the same large-scale forcings (see Endo et al. poster) can reasonably capture the shallow cumulus activity, and are used to investigate the links between model biases and the underlying assumptions of the shallow cumulus scheme used in the model.

  9. Type of gonadotropin used during controlled ovarian stimulation induces differential gene expression in human cumulus cells: A randomized study.

    PubMed

    Cruz, María; Requena, Antonio; Agudo, David; García-Velasco, Juan Antonio

    2017-08-01

    The cumulus-oocyte complex plays a central role in the regulation of folliculogenesis where it is important for the maturation, reprogramming, and fertilization of oocytes. Consequently, cumulus cell gene expression profiling is being explored as a promising method for assessing oocyte competence in the near future. Through DNA microarray technology, we analyzed the potential differences in the gene expression profiles of cumulus cells from preovulatory follicles after controlled ovarian stimulation using different types of gonadotropins. A prospective, randomized study was performed among 90 women participating in an oocyte donation program. Subjects were assigned to receive recombinant follicle-stimulating hormone (FSH), urinary FSH, or human menopausal gonadotropin (hMG). The gene expression profile in cumulus cells was analyzed according the type of gonadotropin received during ovarian stimulation. Furthermore, we also performed a gene ontology analysis to provide structural knowledge. Hierarchical clustering, principal component analysis, and gene enrichment analysis revealed greater differences between the urinary FSH and hMG groups compared to the rest of the pair-wise comparisons; recombinant FSH vs hMG and urinary FSH vs recombinant FSH. Data suggest that controlled ovarian stimulation induces specific gene expression profiles in human cumulus cells depending on the type of gonadotropin used. Registered at clinicaltrials.gov; identifier NCT022437032. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. cyclic GMP Mediated Inhibition of Spontaneous Germinal Vesicle Breakdown Both with and without Cumulus in Mouse Oocyte

    PubMed Central

    Hwang, Heekyung; Cheon, Yong-Pil

    2016-01-01

    ABSTRACT Intact germinal vesicle (GV) arrest and release are essential for maintaining the fertility of mammals inducing human. Intact germinal vesicle release, maturation of oocytes is maintained by very complex procedures along with folliculogenesis and is a critical step for embryonic development. Cyclic guanosine monophosphate (cGMP) has been suggested a key factor for meiotic arrest but so far its mechanisms are controversy. In this study we examine the effects of cGMP on germinal vesicle breakdown in cumulus-enclosed oocytes and denuded oocytes. Spontaneous maturation was inhibited by a cGMP agonist, 8-Br-cGMP with concentration dependent manners both in cumulus-enclosed oocytes and denuded oocytes. The inhibitory effect was more severe in denuded oocytes than cumulus-enclosed oocytes. The Rp-8-Br-cGMP and Rp-pCPT-8-Br-cGMP did not severely block GVB compared to 8-Br-cGMP. The spontaneous GVB inhibitory effects were different by the existence of cumulus. Based on them it is suggested that the cumulus modulates the role of cGMP in GV arrest. PMID:28144640

  11. The effects of discontinuities in the Betts Miller cumulus convection scheme on four-dimensional variational data assimilation

    NASA Astrophysics Data System (ADS)

    Zupanski, Dušanka

    1993-10-01

    A tangent linear and an adjoint of the large-scale precipitation and the cumulus convection processes in the National Meteorological Center's NMC/ETA regional forecast model are developed. The effects of discontinuities in the Betts Miller cumulus convection scheme are examined and applicability of derivative minimization methods in four-dimensional variational (4D VAR) data assimilation is considered. It is demonstrated that discontinuities present in the control Betts Miller cumulus convection scheme increase linearization errors to a large extent and have adverse effects on 4D VAR data assimilation. In the experiments performed, discontinuities in the cumulus convection scheme have the most serious effect in low layers. These problems can be reduced by modifying the scheme to make it more continuous in low layers. Positive effects of inclusion of cumulus convection in 4D VAR data assimilation are found in upper layers, especially in humidity fields. The "observations" used are optimal interpolation analyses of temperature, surface pressure, wind and specific humidity. By inclusion of other data, more closely related to the convective processes, such as precipitation and clouds, more benefits should be expected. Even with the difficulties caused by discontinuities, derivative minimization techniques appear to work for the data assimilation problems. In order to get more general conclusions, more experiments are needed with different synoptic situations. The inclusion of other important physical processes such as radiation, surface friction and turbulence in the forecast and the corresponding adjoint models could alter the results since they may reinforce the effects of discontinuities.

  12. Energy solutions in rural Africa: mapping electrification costs of distributed solar and diesel generation versus grid extension

    NASA Astrophysics Data System (ADS)

    Szabó, S.; Bódis, K.; Huld, T.; Moner-Girona, M.

    2011-07-01

    Three rural electrification options are analysed showing the cost optimal conditions for a sustainable energy development applying renewable energy sources in Africa. A spatial electricity cost model has been designed to point out whether diesel generators, photovoltaic systems or extension of the grid are the least-cost option in off-grid areas. The resulting mapping application offers support to decide in which regions the communities could be electrified either within the grid or in an isolated mini-grid. Donor programs and National Rural Electrification Agencies (or equivalent governmental departments) could use this type of delineation for their program boundaries and then could use the local optimization tools adapted to the prevailing parameters. The views expressed in this paper are those of the authors and do not necessarily represent European Commission and UNEP policy.

  13. Observational estimates of detrainment and entrainment in non-precipitating shallow cumulus

    NASA Astrophysics Data System (ADS)

    Norgren, M. S.; Small, J. D.; Jonsson, H. H.; Chuang, P. Y.

    2014-08-01

    Vertical transport associated with cumulus clouds is important to the redistribution of gases, particles and energy, with subsequent consequences for many aspects of the climate system. Previous studies have suggested that detrainment from clouds can be comparable to the updraft mass flux, and thus represents an important contribution to vertical transport. In this study, we describe a new method to deduce the amounts of gross detrainment and entrainment experienced by non-precipitating cumulus clouds using aircraft observations. The method utilizes equations for three conserved variables: cloud mass, total water and moist static energy. Optimizing these three equations leads to estimates of the mass fractions of adiabatic mixed-layer air, entrained air and detrained air that the sampled cloud has experienced. The method is applied to six flights of the CIRPAS Twin Otter during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) which took place in the Houston, Texas region during the summer of 2006 during which 176 small, non-precipitating cumulus were sampled. Our analysis suggests that, on average, these clouds were comprised of 30 to 70% mixed-layer air, with entrained air comprising most of the remainder. The mass fraction of detrained air was less than 2% for a majority of the clouds, although 15% of them did exhibit detrained air fractions larger than 10%. Entrained and detrained air mass fractions both increased with altitude, and the largest detrainment events were almost all associated with air that was at their level of neutral buoyancy, findings that are consistent with previous studies.

  14. Numerical Simulation of Chennai Heavy Rainfall Using MM5 Mesoscale Model with Different Cumulus Parameterization Schemes

    NASA Astrophysics Data System (ADS)

    Litta, A. J.; Chakrapani, B.; Mohankumar, K.

    2007-07-01

    Heavy rainfall events become significant in human affairs when they are combined with hydrological elements. The problem of forecasting heavy precipitation is especially difficult since it involves making a quantitative precipitation forecast, a problem well recognized as challenging. Chennai (13.04°N and 80.17°E) faced incessant and heavy rain about 27 cm in 24 hours up to 8.30 a.m on 27th October 2005 completely threw life out of gear. This torrential rain caused by deep depression which lay 150km east of Chennai city in Bay of Bengal intensified and moved west north-west direction and crossed north Tamil Nadu and south Andhra Pradesh coast on 28th morning. In the present study, we investigate the predictability of the MM5 mesoscale model using different cumulus parameterization schemes for the heavy rainfall event over Chennai. MM5 Version 3.7 (PSU/NCAR) is run with two-way triply nested grids using Lambert Conformal Coordinates (LCC) with a nest ratio of 3:1 and 23 vertical layers. Grid sizes of 45, 15 and 5 km are used for domains 1, 2 and 3 respectively. The cumulus parameterization schemes used in this study are Anthes-Kuo scheme (AK), the Betts-Miller scheme (BM), the Grell scheme (GR) and the Kain-Fritsch scheme (KF). The present study shows that the prediction of heavy rainfall is sensitive to cumulus parameterization schemes. In the time series of rainfall, Grell scheme is in good agreement with observation. The ideal combination of the nesting domains, horizontal resolution and cloud parameterization is able to simulate the heavy rainfall event both qualitatively and quantitatively.

  15. The microstructure of selected, small, isolated, cumulus clouds near Red Deer, Alberta

    NASA Astrophysics Data System (ADS)

    Kochtubajda, B.

    Physical experiments designed to explore the potential of rain augmentation through airborne glaciogenic seeding on small, isolated non-precipitating cumuliform clouds near Red Deer, Alberta were carried out during the period 1982-1985. The microstructure of 90 cumulus congestus clouds have been documented through repeated in-situ sampling using a cloud physics instrumented aircraft platform. Observations from the inspection passes of 57 clouds seeded with either dry ice pellets or silver iodide pyrotechnics, and all the passes of 33 natural clouds are presented. Measurements of the cloud droplet concentration indicate that Alberta cumulus clouds are typically continental in nature, with an average droplet concentration of 535 cm -3 and an average droplet diameter of 10.6 μm. Alberta clouds have average liquid water contents of 0.57 g m -3, with a peak 1-sec value of 3.17 g m -3. The 1-km average liquid water contents are 0.83 g m -3, with a peak value of 2.81 g m -3. Cloud lifetimes vary between 11 and 20 minutes. Concentrations of naturally occurring ice crystals are found to be low. The average maximum 1-km ice concentration was 31 -1, and the peak 1-km concentration was 73.11 -1 in the natural cloud dataset. Evidence of precipitation-sized particles was detected in 21% (7 of 33) of the clouds, and precipitation below cloud base was detected in 6% (2 of 33) of the clouds. A comparison of the Alberta cloud characteristics to the cumulus clouds from different locations showed that there are some distinct differences between Alberta clouds and the clouds from the other regions.

  16. Effects of cumulus parameterization closures on simulations of summer precipitation over the continental United States

    NASA Astrophysics Data System (ADS)

    Qiao, Fengxue; Liang, Xin-Zhong

    2017-07-01

    This study examines the effects of five cumulus closure assumptions on simulations of summer precipitation in the continental U.S. by utilizing an ensemble cumulus parameterization (ECP) that incorporates multiple alternate closure schemes into a single cloud model formulation. Results demonstrate that closure algorithms significantly affect the summer mean, daily frequency and intensity, and diurnal variation of precipitation, with strong regional dependence. Overall, the vertical velocity (W) closure produces the smallest summer mean biases, while the moisture convergence (MC) closure most realistically reproduces daily variability. Both closures have advantages over others in simulating U.S. daily rainfall frequency distribution, though both slightly overestimate intense rain events. The MC closure is superior at capturing summer rainfall amount, daily variability, and heavy rainfall frequency over the Central U.S., but systematically produces wet biases over the North American Monsoon (NAM) region and Southeast U.S., which can be reduced by using the W closure. The instability tendency (TD) and the total instability adjustment (KF) closures are better at capturing observed diurnal signals over the Central U.S. and the NAM, respectively. The results reasonably explain the systematic behaviors of several major cumulus parameterizations. A preliminary experiment combining two optimal closures (averaged moisture convergence and vertical velocity) in the ECP scheme significantly reduced the wet (dry) biases over the Southeast U.S. in the summer of 1993 (2003), and greatly improved daily rainfall correlations over the NAM. Further improved model simulation skills may be achieved in the future if optimal closures and their appropriate weights can be derived at different time scales based on specific climate regimes.

  17. MicroRNA-224 delays oocyte maturation through targeting Ptx3 in cumulus cells.

    PubMed

    Li, Xiufang; Wang, Huidan; Sheng, Yan; Wang, Zhongqing

    2017-02-01

    MicroRNAs (miRNAs) have been improved to regulate oocyte development in a cell- or stage-specific manner. In this study, we aimed to clarify microRNA-224's (miR-224) role in cumulus cells (CCs), to find out whether a change level of miR-224 in CCs could influence the maturation of oocyte. We found that overexpression of miR-224 of CCs led to the impairment of cell expansion, along with a decrease in the gene expression associated with cell expansion and maturation of oocyte. The increased expression of miR-224 in CC interrupted oocyte cell cycle at the GV stage. The GDF9, BMP15 and ZP3 of the oocytes were also down-regulated. The following in vitro fertilization had yielded a lower number of oocytes from cumulus-oocyte complexes (COCs) overexpressing miR-224 when reaching the blastocyst stage. The suppressive effect of miR-224 in the maturation of COC is validated by the miR-224 knockdown model, where the expansion of cumulus cell was increased and oocyte was developed to MII stage. In addition, the expression of aromatase in CCs was down-regulated by miR-224, resulting in a decreased level of estradiol (E2). A further investigation found that miR-224 down-regulated the expression of protein and mRNA of Ptx3 by targeting its 3'UTR. Our study revealed that miR-224 regulates the gene expression and function of CCs, which influences the maturation of oocyte, at least in part, via targeting Ptx3.

  18. Investigating the scale-adaptivity of a shallow cumulus parameterization scheme with LES

    NASA Astrophysics Data System (ADS)

    Brast, Maren; Schemann, Vera; Neggers, Roel

    2017-04-01

    In this study we investigate the scale-adaptivity of a new parameterization scheme for shallow cumulus clouds in the gray zone. The Eddy-Diffusivity Multiple Mass-Flux (or ED(MF)n ) scheme is a bin-macrophysics scheme, in which subgrid transport is formulated in terms of discretized size densities. While scale-adaptivity in the ED-component is achieved using a pragmatic blending approach, the MF-component is filtered such that only the transport by plumes smaller than the grid size is maintained. For testing, ED(MF)n is implemented in a large-eddy simulation (LES) model, replacing the original subgrid-scheme for turbulent transport. LES thus plays the role of a non-hydrostatic testing ground, which can be run at different resolutions to study the behavior of the parameterization scheme in the boundary-layer gray zone. In this range convective cumulus clouds are partially resolved. We find that at high resolutions the clouds and the turbulent transport are predominantly resolved by the LES, and the transport represented by ED(MF)n is small. This partitioning changes towards coarser resolutions, with the representation of shallow cumulus clouds becoming exclusively carried by the ED(MF)n. The way the partitioning changes with grid-spacing matches the results of previous LES studies, suggesting some scale-adaptivity is captured. Sensitivity studies show that a scale-inadaptive ED component stays too active at high resolutions, and that the results are fairly insensitive to the number of transporting updrafts in the ED(MF)n scheme. Other assumptions in the scheme, such as the distribution of updrafts across sizes and the value of the area fraction covered by updrafts, are found to affect the location of the gray zone.

  19. Effects of cumulus parameterization closures on simulations of summer precipitation over the continental United States

    NASA Astrophysics Data System (ADS)

    Qiao, Fengxue; Liang, Xin-Zhong

    2016-09-01

    This study examines the effects of five cumulus closure assumptions on simulations of summer precipitation in the continental U.S. by utilizing an ensemble cumulus parameterization (ECP) that incorporates multiple alternate closure schemes into a single cloud model formulation. Results demonstrate that closure algorithms significantly affect the summer mean, daily frequency and intensity, and diurnal variation of precipitation, with strong regional dependence. Overall, the vertical velocity (W) closure produces the smallest summer mean biases, while the moisture convergence (MC) closure most realistically reproduces daily variability. Both closures have advantages over others in simulating U.S. daily rainfall frequency distribution, though both slightly overestimate intense rain events. The MC closure is superior at capturing summer rainfall amount, daily variability, and heavy rainfall frequency over the Central U.S., but systematically produces wet biases over the North American Monsoon (NAM) region and Southeast U.S., which can be reduced by using the W closure. The instability tendency (TD) and the total instability adjustment (KF) closures are better at capturing observed diurnal signals over the Central U.S. and the NAM, respectively. The results reasonably explain the systematic behaviors of several major cumulus parameterizations. A preliminary experiment combining two optimal closures (averaged moisture convergence and vertical velocity) in the ECP scheme significantly reduced the wet (dry) biases over the Southeast U.S. in the summer of 1993 (2003), and greatly improved daily rainfall correlations over the NAM. Further improved model simulation skills may be achieved in the future if optimal closures and their appropriate weights can be derived at different time scales based on specific climate regimes.

  20. A stochastic scale-aware parameterization of shallow cumulus convection across the convective gray zone

    NASA Astrophysics Data System (ADS)

    Sakradzija, Mirjana; Seifert, Axel; Dipankar, Anurag

    2016-06-01

    The parameterization of shallow cumuli across a range of model grid resolutions of kilometre-scales faces at least three major difficulties: (1) closure assumptions of conventional parameterization schemes are no longer valid, (2) stochastic fluctuations become substantial and increase with grid resolution, and (3) convective circulations that emerge on the model grids are under-resolved and grid-scale dependent. Here we develop a stochastic parameterization of shallow cumulus clouds to address the first two points, and we study how this stochastic parameterization interacts with the under-resolved convective circulations in a convective case over the ocean. We couple a stochastic model based on a canonical ensemble of shallow cumuli to the Eddy-Diffusivity Mass-Flux parameterization in the icosahedral nonhydrostatic (ICON) model. The moist-convective area fraction is perturbed by subsampling the distribution of subgrid convective states. These stochastic perturbations represent scale-dependent fluctuations around the quasi-equilibrium state of a shallow cumulus ensemble. The stochastic parameterization reproduces the average and higher order statistics of the shallow cumulus case adequately and converges to the reference statistics with increasing model resolution. The interaction of parameterizations with model dynamics, which is usually not considered when parameterizations are developed, causes a significant influence on convection in the gray zone. The stochastic parameterization interacts strongly with the model dynamics, which changes the regime and energetics of the convective flows compared to the deterministic simulations. As a result of this interaction, the emergence of convective circulations in combination with the stochastic parameterization can even be beneficial on the high-resolution model grids.

  1. Ejaculated Mouse Sperm Enter Cumulus-Oocyte Complexes More Efficiently In Vitro than Epididymal Sperm

    PubMed Central

    Suarez, Susan S.

    2015-01-01

    The mouse is an established and popular animal model for studying reproductive biology. Epididymal mouse sperm, which lack exposure to secretions of male accessory glands and do not precisely represent ejaculated sperm for the study of sperm functions, have been almost exclusively used in studies. We compared ejaculated and epididymal sperm in an in vitro fertilization setting to examine whether ejaculated sperm enter cumulus-oocyte complexes more efficiently. In order to prepare sperm for fertilization, they were incubated under capacitating conditions. At the outset of incubation, ejaculated sperm stuck to the glass surfaces of slides and the incidences of sticking decreased with time; whereas, very few epididymal sperm stuck to glass at any time point, indicating differences in surface charge. At the end of the capacitating incubation, when sperm were added to cumulus-oocyte complexes, the form of flagellar movement differed dramatically; specifically, ejaculated sperm predominantly exhibited increased bending on one side of the flagellum (a process termed pro-hook hyperactivation), while epididymal sperm equally exhibited increased bending on one or the other side of the flagellum (pro-hook or anti-hook hyperactivation). This indicates that accessory sex gland secretions might have modified Ca2+ signaling activities in sperm, because the two forms of hyperactivation are reported to be triggered by different Ca2+ signaling patterns. Lastly, over time, more ejaculated than epididymal sperm entered the cumulus oocyte complexes. We concluded that modification of sperm by male accessory gland secretions affects the behavior of ejaculated sperm, possibly providing them with an advantage over epididymal sperm for reaching the eggs in vivo. PMID:25996155

  2. Barbados Cloud Observatory: The detection of weak Radar reflectivity signals below shallow cumulus clouds

    NASA Astrophysics Data System (ADS)

    Klingebiel, Marcus; Hirsch, Lutz; Stevens, Bjorn

    2017-04-01

    The Barbados Cloud Observatory (BCO) is located on the east coast of the island of Barbados (13° 09' N, 59° 25' W), where it is exposed to the relatively undisturbed easterly trade winds. The position of the BCO is well suited for studies of shallow cumulus clouds, which have a significant impact on Earth's radiation budget and on the energy and water cycles. In the presented study, measurements from a K-band cloud radar, with an exceptional sensitivity, and a ceilometer are used to analyze the lower environment of shallow cumulus clouds. Below their nominal base, which is well defined by the determination of the lifting condensation level and the ceilometer measurements, the cloud radar detects a weak reflectivity signal. This signal is observable down to 250 m below the cloud base and shows an intensity between -50 dBZ and -65 dBZ. Artifacts, caused by the radar instrument itself (e.g. Bragg-Scattering) or by objects other than hydrometeors, cannot produce this weak reflectivity signal. We suggest that small raindrops (400 µm diameter or larger) develop inside the upper part of the cloud and fall into the region below the cloud, where they cause the weak radar reflectivity signal. These drops must have a very low number concentration (1 drop/100 m3) since they are not visible to the human eye. Radiosonde data and satellite images indicate that the occurrence of the weak radar reflectivity signal is connected to the humidity conditions in higher altitudes (up to 2500 m). A high relative humidity at this altitude allows for a larger vertical extension of a cloud and thus makes it easier for raindrops to develop inside the cloud and then fall below cloud base. This phenomenon is interesting, because the appearance of droplets with a low number concentration below shallow cumulus clouds could be a precursor of surface precipitation.

  3. Structural characterization of PTX3 disulfide bond network and its multimeric status in cumulus matrix organization.

    PubMed

    Inforzato, Antonio; Rivieccio, Vincenzo; Morreale, Antonio P; Bastone, Antonio; Salustri, Antonietta; Scarchilli, Laura; Verdoliva, Antonio; Vincenti, Silvia; Gallo, Grazia; Chiapparino, Caterina; Pacello, Lucrezia; Nucera, Eleonora; Serlupi-Crescenzi, Ottaviano; Day, Anthony J; Bottazzi, Barbara; Mantovani, Alberto; De Santis, Rita; Salvatori, Giovanni

    2008-04-11

    PTX3 is an acute phase glycoprotein that plays key roles in resistance to certain pathogens and in female fertility. PTX3 exerts its functions by interacting with a number of structurally unrelated molecules, a capacity that is likely to rely on its complex multimeric structure stabilized by interchain disulfide bonds. In this study, PAGE analyses performed under both native and denaturing conditions indicated that human recombinant PTX3 is mainly composed of covalently linked octamers. The network of disulfide bonds supporting this octameric assembly was resolved by mass spectrometry and Cys to Ser site-directed mutagenesis. Here we report that cysteine residues at positions 47, 49, and 103 in the N-terminal domain form three symmetric interchain disulfide bonds stabilizing four protein subunits in a tetrameric arrangement. Additional interchain disulfide bonds formed by the C-terminal domain cysteines Cys(317) and Cys(318) are responsible for linking the PTX3 tetramers into octamers. We also identified three intrachain disulfide bonds within the C-terminal domain that we used as structural constraints to build a new three-dimensional model for this domain. Previously it has been shown that PTX3 is a key component of the cumulus oophorus extracellular matrix, which forms around the oocyte prior to ovulation, because cumuli from PTX3(-/-) mice show defective matrix organization. Recombinant PTX3 is able to restore the normal phenotype ex vivo in cumuli from PTX3(-/-) mice. Here we demonstrate that PTX3 Cys to Ser mutants, mainly assembled into tetramers, exhibited wild type rescue activity, whereas a mutant, predominantly composed of dimers, had impaired functionality. These findings indicate that protein oligomerization is essential for PTX3 activity within the cumulus matrix and implicate PTX3 tetramers as the functional molecular units required for cumulus matrix organization and stabilization.

  4. Sensitivity of PBL and Cumulus schemes for Thunderstorm prediction over an Indian Region

    NASA Astrophysics Data System (ADS)

    Kumar, Dinesh; Charan Mohanty, Uma; Kumar, Krishan

    2015-04-01

    The cloud processes play an important role in all forms of precipitation. Its proper representation is one of the challenging tasks in mesoscale numerical simulation. Studies have revealed that mesoscale feature require proper initialization which may likely to improve the convective system rainfall forecasts. Understanding the precipitation process, model initial condition accuracy and resolved/sub grid-scale precipitation processes representation, are the important areas which needed to improve in order to represent the mesoscale features properly. Various attempts have been done in order to improve the model performance through grid resolution, physical parameterizations, etc. But it is the physical parameterizations which provide a convective atmosphere for the development and intensification of convective events. Further, physical parameterizations consist of cumulus convection, surface fluxes of heat, moisture, momentum, and vertical mixing in the planetary boundary layer (PBL). How PBL and Cumulus schemes capture the evolution of thunderstorm have been analysed by taking thunderstorm cases occurred over Kolkata, India in the year 2011. PBL and cumulus schemes were customized for WSM-6 microphysics because WSM series has been widely used in operational forecast. Results have shown that KF (PBL scheme) and WSM-6 (Cumulus Scheme) have reproduced the evolution of surface variable such as CAPE, temperature and rainfall very much like observation. Further, KF and WSM-6 scheme also provided the increased moisture availability in the lower atmosphere which was taken to higher level by strong vertical velocities providing a platform to initiate a thunderstorm much better. Overestimation of rain in WSM-6 occurs primarily because of occurrence of melting and freezing process within a deeper layer in WSM-6 scheme. These Schemes have reproduced the spatial pattern and peak rainfall coverage closer to TRMM observation. It is the the combination of WSM-6, and KF schemes

  5. Boundary-layer cumulus over land: Some observations and conceptual models

    SciTech Connect

    Stull, R.B.

    1993-09-01

    Starting in 1980, the Boundary Layer Research Team at the University of Wisconsin has been systematically studying the formation and evolution of nonprecipitating boundary-layer cumulus clouds (BLCu) in regions of fair weather (anticyclones) over land (Stull, 1980). Our approach is to quantify the average statistical characteristics of the surface, thermals, boundary layer, and clouds over horizontal regions of roughly 20 km in diameter. Within such a region over land, there is typically quite a variation in land use, and associated variations in surface albedo and moisture.

  6. Interaction of the ABL with stratocumulus and cumulus cloud layers, appendix N

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1984-01-01

    The role of the atmospheric boundary layer (ABL) over the oceans which in the general circulation of the atmosphere is to supply moisture to cumulus and stratus clouds is outlined. In extreme weather events, such as powerful storms and intense droughts, the primary role of the ABL is to supply or deny moisture to the weather system. Even for routine weather regimes, cloudiness and precipitation are key elements of any forecast. The premier problem for ABL parameterization is to formulate the physical coupling between the ABL turbulence and the clouds.

  7. Cumulus cloud base height estimation from high spatial resolution Landsat data - A Hough transform approach

    NASA Technical Reports Server (NTRS)

    Berendes, Todd; Sengupta, Sailes K.; Welch, Ron M.; Wielicki, Bruce A.; Navar, Murgesh

    1992-01-01

    A semiautomated methodology is developed for estimating cumulus cloud base heights on the basis of high spatial resolution Landsat MSS data, using various image-processing techniques to match cloud edges with their corresponding shadow edges. The cloud base height is then estimated by computing the separation distance between the corresponding generalized Hough transform reference points. The differences between the cloud base heights computed by these means and a manual verification technique are of the order of 100 m or less; accuracies of 50-70 m may soon be possible via EOS instruments.

  8. Interaction of the ABL with stratocumulus and cumulus cloud layers, appendix N

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1984-01-01

    The role of the atmospheric boundary layer (ABL) over the oceans which in the general circulation of the atmosphere is to supply moisture to cumulus and stratus clouds is outlined. In extreme weather events, such as powerful storms and intense droughts, the primary role of the ABL is to supply or deny moisture to the weather system. Even for routine weather regimes, cloudiness and precipitation are key elements of any forecast. The premier problem for ABL parameterization is to formulate the physical coupling between the ABL turbulence and the clouds.

  9. Cumulus cloud base height estimation from high spatial resolution Landsat data - A Hough transform approach

    NASA Technical Reports Server (NTRS)

    Berendes, Todd; Sengupta, Sailes K.; Welch, Ron M.; Wielicki, Bruce A.; Navar, Murgesh

    1992-01-01

    A semiautomated methodology is developed for estimating cumulus cloud base heights on the basis of high spatial resolution Landsat MSS data, using various image-processing techniques to match cloud edges with their corresponding shadow edges. The cloud base height is then estimated by computing the separation distance between the corresponding generalized Hough transform reference points. The differences between the cloud base heights computed by these means and a manual verification technique are of the order of 100 m or less; accuracies of 50-70 m may soon be possible via EOS instruments.

  10. Design and Implementation of Improved Electronic Load Controller for Self-Excited Induction Generator for Rural Electrification

    PubMed Central

    Kathirvel, C.; Porkumaran, K.; Jaganathan, S.

    2015-01-01

    This paper offers an alternative technique, namely, Improved Electronic Load Controller (IELC), which is proposal to improve power quality, maintaining voltage at frequency desired level for rural electrification. The design and development of IELC are considered as microhydroenergy system. The proposed work aims to concentrate on the new schemes for rural electrification with the help of different kinds of hybrid energy systems. The objective of the proposed scheme is to maintain the speed of generation against fluctuating rural demand. The Electronic Load Controller (ELC) is used to connect and disconnect the dump load during the operation of the system, and which absorbs the load when consumer are not in active will enhance the lifestyle of the rural population and improve the living standards. Hydroelectricity is a promising option for electrification of remote villages in India. The conventional methods are not suitable to act as standalone system. Hence, the designing of a proper ELC is essential. The improved electronic load control performance tested with simulation at validated through hardware setup. PMID:26783553

  11. Boundary-layer cumulus over heterogeneous landscapes: A subgrid GCM parameterization. Final report, December 1991--November 1995

    SciTech Connect

    Stull, R.B.; Tripoli, G.

    1996-01-08

    The authors developed single-column parameterizations for subgrid boundary-layer cumulus clouds. These give cloud onset time, cloud coverage, and ensemble distributions of cloud-base altitudes, cloud-top altitudes, cloud thickness, and the characteristics of cloudy and clear updrafts. They tested and refined the parameterizations against archived data from Spring and Summer 1994 and 1995 intensive operation periods (IOPs) at the Southern Great Plains (SGP) ARM CART site near Lamont, Oklahoma. The authors also found that: cloud-base altitudes are not uniform over a heterogeneous surface; tops of some cumulus clouds can be below the base-altitudes of other cumulus clouds; there is an overlap region near cloud base where clear and cloudy updrafts exist simultaneously; and the lognormal distribution of cloud sizes scales to the JFD of surface layer air and to the shape of the temperature profile above the boundary layer.

  12. The importance of manganese in the cytoplasmic maturation of cattle oocytes: blastocyst production improvement regardless of cumulus cells presence during in vitro maturation.

    PubMed

    Anchordoquy, Juan Patricio; Anchordoquy, Juan Mateo; Sirini, Matias Angel; Testa, Juan Alberto; Peral-García, Pilar; Furnus, Cecilia Cristina

    2016-02-01

    Adequate dietary intake of manganese (Mn) is required for normal reproductive performance in cattle. This study was carried out to investigate the effect of Mn during in vitro maturation of bovine cumulus-oocyte complexes (COC) on apoptosis of cumulus cells, cumulus expansion, and superoxide dismutase (SOD) activity in the COC. The role of cumulus cells on Mn transport and subsequent embryo development was also evaluated. Early apoptosis decreased in cumulus cells matured with Mn compared with medium alone. Cumulus expansion did not show differences in COC matured with or without Mn supplementation. SOD activity was higher in COC matured with 6 ng/ml Mn than with 0 ng/ml Mn. Cleavage rates were higher in COC and denuded oocytes co-cultured with cumulus cells, either with or without Mn added to in vitro maturation (IVM) medium. Regardless of the presence of cumulus cells during IVM, the blastocyst rates were higher when 6 ng/ml Mn was supplemented into IVM medium compared with growth in medium alone. Blastocyst quality was enhanced when COC were matured in medium with Mn supplementation. The results of the present study indicated that Mn supplementation to IVM medium enhanced the 'health' of COC, and improved subsequent embryo development and embryo quality.

  13. Sensitivity of the thermal balance in a general circulation model to a parameterization for cumulus convection with radiatively interactive clouds

    SciTech Connect

    Donner, L.J.

    1986-11-01

    The dependence of thermal balance of a general circulation model on the parameterization of cumulus convection is investigated. Incorporation of a Kuo-type cumulus parameterization into the NCAR community climate model decreases temperatures in most of the lower and middle tropospheres while increasing temperatures slightly at the tropopause, decreases both relative and specific humidities in large parts of the lower troposphere, and also reduces cloud cover and tropical precipitation. Although the Kuo parameterization represents a vertically integrated heat source, its presence in the general circulation model causes an even larger reduction in heating by the moist adiabatic adjustment, so the total heating associated with cumulus convection is less if the Kuo parameterization is used. The reduction in atmospheric temperatures relative to those at the surface with the Kuo parameterization results in enhanced heating of the lower atmosphere by surface exchange processes. These changes in convective and surface heating dominate changes in the diabatic part of the thermal balance but are moderated by changes in radiative heating associated with reduced cloudiness. Diabatic heating changes are balanced primarily by reduced mean dynamic transport of heat associated with a weakened Hadley circulation. Dependence of the circulation sensitivity to cumulus parameterization of cloud-convection feedback and the penetrative extent of convection is found to be significant. Penetrative depth of convection is especially important; since penetration by convection depends crucially on the poorly understood entrainment process, some uncertainty plagues estimates of the details of the impact of cumulus convection on the simulated general circulation. Changes in cloudiness associated with the Kuo parameterization alter radiative forcing so as to reduce the sensitivity of the community climate model to the cumulus parameterization.

  14. Non-invasive assessment of porcine oocyte quality by supravital staining of cumulus-oocyte complexes with lissamine green B.

    PubMed

    Dutta, Rahul; Li, Shun; Fischer, Konrad; Kind, Alexander; Flisikowska, Tatiana; Flisikowski, Krzysztof; Rottmann, Oswald; Schnieke, Angelika

    2016-06-01

    We evaluated the usefulness of lissamine green B (LB) staining of cumulus-oocyte complexes (COC) as a non-invasive method of predicting maturational and developmental competence of slaughterhouse-derived porcine oocytes cultured in vitro. Cumulus cells of freshly aspirated COCs were evaluated either morphologically on the basis of thickness of cumulus cell layers, or stained with LB, which penetrates only non-viable cells. The extent of cumulus cell staining was taken as an inverse indicator of membrane integrity. The two methods of COC grading were then examined as predictors of nuclear maturation and development after parthenogenetic activation. In both cases LB staining proved a more reliable indicator than morphological assessment (P < 0.05). The relationship between LB staining and cumulus cell apoptosis was also examined. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay for DNA fragmentation revealed that oocytes within COCs graded as low quality by either LB staining or visual morphology showed significantly greater DNA fragmentation (P < 0.05) than higher grades, and that LB and visual grading were of similar predictive value. Expression of the stress response gene TP53 showed significantly higher expression in COCs graded as low quality by LB staining. However expression of the apoptosis-associated genes BAK and CASP3 was not significantly different between high or low grade COCs, suggesting that mRNA expression of BAK and CASP3 is not a reliable method of detecting apoptosis in porcine COCs. Evaluation of cumulus cell membrane integrity by lissamine green B staining thus provides a useful new tool to gain information about the maturational and developmental competence of porcine oocytes.

  15. Storm morphology and electrification from CHUVA-GLM Vale do Paraiba field campaign

    NASA Astrophysics Data System (ADS)

    Albrecht, R. I.; Morales, C.; Lima, W. F.; Biscaro, T. S.; Mello, I. B.

    2013-12-01

    CHUVA [Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)] Project is a series of itinerant field campaigns with the objective of characterizing the main precipitating systems observed in Brazil as a support for Global Precipitation Measurement (GPM) mission. The fourth field campaign was conducted at Vale do Paraiba in São Paulo, Brazil, from 1 November 2011 to 31 March 2012. For this specific field experiment, several lightning location systems (LLS) were deployed as part of GOES-R Geostationary Lightning Mapper (GLM) and MTG Lightning Imager (LI) pre-launch activities, resulting in a joint effort between INPE, USP, NOAA, NASA, EUMETSAT and several vendors of operational LLS for network intercomparison and GLM and LI proxy data generation. Among these networks, 4 of them detect total (intra-cloud and cloud-to-ground) lightning, including a Lightning Mapping Array (LMA), allowing a detailed description of the cloud electrification. To depict precipitating weather systems, CHUVA uses a mobile XPOL Doppler Radar, micro-rain radars, disdrometers, rain gauges, microwave radiometer, Lidar, and a GPS network for water vapor retrievals. Also, Vale do Paraíba and São Paulo are covered by 3 operational S-band radars. The precipitation data collected by these radars and the lightning detected by the LLS were grouped in a structure of storm features built by tracking the precipitating systems and its associated lightning. This storm feature database makes it easier to group similar convective systems and compare them in terms of area, lifetime, rainfall and convection intensity, lightning activity, and more. During this field experiment a large variety of cloud systems were sampled: cold fronts, squall lines, the South Atlantic Convergence Zone (SACZ) and local convective systems. Microphysical characteristics (such as hydrometeor identification and ice/water mass) of

  16. Investigations of Sprites During the Severe Thunderstorm Electrification and Precipitation Study

    NASA Astrophysics Data System (ADS)

    Lyons, W. A.; Nelson, T. E.; Cummer, S. A.; Wiens, K. C.; Bedard, A. J.; Williams, E. R.; Lyons, L. N.

    2002-12-01

    During the summer of 2000, a large multi-organization field program was conducted on the U.S. High Plains, near Goodland, KS. STEPS (the Severe Thunderstorm Electrification and Precipitation Study) focused on improving our understanding of the co-evolving dynamical, microphysical and electrical properties of convective storms, especially those producing positive cloud-to-ground lightning (+CGs). The New Mexico Tech 3-D Lightning Mapping Array (LMA) provided measurements of the height from which electrical charge was lowered to ground, along with the areal coverage of the discharge. Coincident with these measurements, remote low-light television cameras detected many sprites and transient luminous events above the storms from the Yucca Ridge Field Station. ELF transients were recorded in Rhode Island (by MIT) and North Carolina (by Duke). These two systems use similar, but not identical, methodologies to estimate total charge moment changes for lightning discharges. Detailed analyses of LMA and ELF charge moment data have been condcuted for a number of sprite producing +CGs for the 19 July MCS finding, as expected, large charge moment changes (>500-1000 C km) and rather low charge removal heights (~4 km AGL). A detailed study is now underway to assess the charge moment changes for those +CGs in this storm for which no sprites were observed. A similar analysis is being conducted for the storms of 29 - 30 June 2000. The initial phase of this storm contained numerous +CGs associated with a tornadic supercell. The height from which charges were lowered were characteristically higher than in the MCS. We anticipate that the charge moment changes, however, will be substantially lower for those sprite-producing +CGs which occurred later in this storm's evolution. Additionally, infrasound (0.5 to 5 Hz) measurements were obtained by NOAA ETL both at Goodland, KS and Boulder, CO. The 19 July storm produced unique infrasound signatures which temporally matched many sprite

  17. The electrification of Nova Scotia, 1884--1973: Technological modernization as a response to regional disparity

    NASA Astrophysics Data System (ADS)

    King, Lionel Bradley

    This dissertation investigates local attempts to use technology as a force for regional rehabilitation in the economically-depressed Maritime region of Canada. At the time of Confederation in 1867, the Maritime province of Nova Scotia was prosperous, progressive, and cultured. By the end of the 1910s, the province had entered a long period of economic and social decline. Recent historiography has shown that, far from passively accepting their fate, Nova Scotians and other Maritimers, actively resisted marginalization with political, cultural, or social action. The thesis expands upon that literature by exploring technology-based strategies of provincial rehabilitation using Thomas P. Hughes's systems perspective and David E. Nye's semiotic approach. In doing so, it applies methods from the social constructivist school of the history of technology to the larger concerns of Maritime Canadian historiography. In large part, the North American culture of technology determined the ways in which Nova Scotians applied technological solutions to provincial concerns. Technology has long been central to the Western idea of progress. As the "high technology" of the late nineteenth and early twentieth centuries, electricity reinforced that view: its ephemeral nature and silent efficiency led people to endow it with transformative, even mystical, powers. As a result, Nova Scotians, adopted a program of electrical modernization in the late 1910s as a remedy for regional disparity. The Nova Scotia government's first step was the creation of an Ontario-style hydroelectric commission designed to bring order to the province's fragmented and inefficient electrical network. Over the next few decades, the Nova Scotia Power Commission implemented rural electrification, home modernization, and regional system-building models that had already proven successful in Ontario and the United States. The system-building philosophies behind these programs were adapted to local conditions and

  18. Project Overview: Cumulus Humilis Aerosol Processing Study (CHAPS): Proposed Summer 2007 ASP Field Campaign

    SciTech Connect

    Berkowitz, Carl M.; Berg, Larry K.; Ogren, J. A.; Hostetler, Chris A.; Ferrare, Richard

    2006-05-18

    This white paper presents the scientific motivation and preliminary logistical plans for a proposed ASP field campaign to be carried out in the summer of 2007. The primary objective of this campaign is to use the DOE Gulfstream-1 aircraft to make measurements characterizing the chemical, physical and optical properties of aerosols below, within and above large fields of fair weather cumulus and to use the NASA Langley Research Center’s High Spectral Resolution Lidar (HSRL) to make independent measurements of aerosol backscatter and extinction profiles in the vicinity of these fields. Separate from the science questions to be addressed by these observations will be information to add in the development of a parameterized cumulus scheme capable of including multiple cloud fields within a regional or global scale model. We will also be able to compare and contrast the cloud and aerosol properties within and outside the Oklahoma City plume to study aerosol processes within individual clouds. Preliminary discussions with the Cloud and Land Surface Interaction Campaign (CLASIC) science team have identified overlap between the science questions posed for the CLASIC Intensive Operation Period (IOP) and the proposed ASP campaign, suggesting collaboration would benefit both teams.

  19. Aerosol and gas re-distribution by shallow cumulus clouds: An investigation using airborne measurements

    NASA Astrophysics Data System (ADS)

    Wonaschuetz, Anna; Sorooshian, Armin; Ervens, Barbara; Chuang, Patrick Y.; Feingold, Graham; Murphy, Shane M.; de Gouw, Joost; Warneke, Carsten; Jonsson, Haflidi H.

    2012-09-01

    Aircraft measurements during the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) are used to examine the influence of shallow cumulus clouds on vertical profiles of aerosol chemical composition, size distributions, and secondary aerosol precursor gases. The data show signatures of convective transport of particles, gases and moisture from near the surface to higher altitudes, and of aqueous-phase production of aerosol mass (sulfate and organics) in cloud droplets and aerosol water. In cloudy conditions, the average aerosol volume concentration at an altitude of 2850 m, above typical cloud top levels, was found to be 34% of that at 450 m; for clear conditions, the same ratio was 13%. Both organic and sulfate mass fractions were on average constant with altitude (around 50%); however, the ratio of oxalate to organic mass increased with altitude (from 1% at 450 m to almost 9% at 3450 m), indicative of the influence of in-cloud production on the vertical abundance and characteristics of secondary organic aerosol (SOA) mass. A new metric termed "residual cloud fraction" is introduced as a way of quantifying the "cloud processing history" of an air parcel. Results of a parcel model simulating aqueous phase production of sulfate and organics reproduce observed trends and point at a potentially important role of SOA production, especially oligomers, in deliquesced aerosols. The observations emphasize the importance of shallow cumulus clouds in altering the vertical distribution of aerosol properties that influence both their direct and indirect effect on climate.

  20. Impact of Anthropogenic Aerosol on the Properties of Shallow Maritime Cumulus Clouds

    NASA Astrophysics Data System (ADS)

    Gao, L.; Wilcox, E. M.; Shan, Y.

    2015-12-01

    The northern Indian Ocean region is frequently covered by cumulus clouds that are responsible for moistening the boundary layer and contribute to tropical deep convection. Because this region is uniquely located close to the highly polluted Indian plateau, air mass with high aerosol concentration can be easily transported to this area. These small cumulus clouds, coupled with the effects of aerosol, have a large potential to affect the regional and global albedo. The aerosol effects on cloud properties and atmospheric structures are examined in this work, using the UAV (Unmanned Aerial Vehicle) data that are observed from CARDEX (Cloud, Aerosol, Radiative forcing, Dynamics EXperiment) and MAC (Maldives Autonomous unmanned aerial vehicle Campaign). On average, the high polluted cases show warmer temperature through the entire atmospheric column and higher relative humidity in boundary layer. The maximum temperature difference between high and low polluted cases can be found around the cloud layer altitude. In addition, the height of sub-cloud mixed layer is higher in low polluted cases. Clouds in high polluted cases are generally becoming narrower and taller than those in low polluted cases, and are associated with greater cloud water content and higher cloud droplet number concentrations, especially in small droplet range (diameters less than 10 micrometers). Meanwhile, the effective radius of cloud droplets decreases as the aerosol concentration increases. These facts indicate that the high polluted clouds are on average brighter with higher albedo.

  1. Laboratory simulations show diabatic heating drives cumulus-cloud evolution and entrainment.

    PubMed

    Narasimha, Roddam; Diwan, Sourabh Suhas; Duvvuri, Subrahmanyam; Sreenivas, K R; Bhat, G S

    2011-09-27

    Clouds are the largest source of uncertainty in climate science, and remain a weak link in modeling tropical circulation. A major challenge is to establish connections between particulate microphysics and macroscale turbulent dynamics in cumulus clouds. Here we address the issue from the latter standpoint. First we show how to create bench-scale flows that reproduce a variety of cumulus-cloud forms (including two genera and three species), and track complete cloud life cycles--e.g., from a "cauliflower" congestus to a dissipating fractus. The flow model used is a transient plume with volumetric diabatic heating scaled dynamically to simulate latent-heat release from phase changes in clouds. Laser-based diagnostics of steady plumes reveal Riehl-Malkus type protected cores. They also show that, unlike the constancy implied by early self-similar plume models, the diabatic heating raises the Taylor entrainment coefficient just above cloud base, depressing it at higher levels. This behavior is consistent with cloud-dilution rates found in recent numerical simulations of steady deep convection, and with aircraft-based observations of homogeneous mixing in clouds. In-cloud diabatic heating thus emerges as the key driver in cloud development, and could well provide a major link between microphysics and cloud-scale dynamics.

  2. Absence of cumulus cells during in vitro maturation affects lipid metabolism in bovine oocytes.

    PubMed

    Auclair, Sylvain; Uzbekov, Rustem; Elis, Sébastien; Sanchez, Laura; Kireev, Igor; Lardic, Lionel; Dalbies-Tran, Rozenn; Uzbekova, Svetlana

    2013-03-15

    Cumulus cells (CC) surround the oocyte and are coupled metabolically through regulation of nutrient intake. CC removal before in vitro maturation (IVM) decreases bovine oocyte developmental competence without affecting nuclear meiotic maturation. The objective was to investigate the influence of CC on oocyte cytoplasmic maturation in relation to energy metabolism. IVM with either cumulus-enclosed (CEO) or -denuded (DO) oocytes was performed in serum-free metabolically optimized medium. Transmission electron microscopy revealed different distribution of membrane-bound vesicles and lipid droplets between metaphase II DO and CEO. By Nile Red staining, a significant reduction in total lipid level was evidenced in DO. Global transcriptomic analysis revealed differential expression of genes regulating energy metabolism, transcription, and translation between CEO and DO. By Western blot, fatty acid synthase (FAS) and hormone-sensitive phospholipase (HSL) proteins were detected in oocytes and in CC, indicating a local lipogenesis and lypolysis. FAS protein was significantly less abundant in DO that in CEO and more highly expressed in CC than in the oocytes. On the contrary, HSL protein was more abundant in oocytes than in CC. In addition, active Ser⁵⁶³-phosphorylated HSL was detected in the oocytes only after IVM, and its level was similar in CEO and DO. In conclusion, absence of CC during IVM affected lipid metabolism in the oocyte and led to suboptimal cytoplasmic maturation. Thus, CC may influence the oocyte by orienting the consumption of nutritive storage via regulation of local fatty acid synthesis and lipolysis to provide energy for maturation.

  3. Laboratory simulations show diabatic heating drives cumulus-cloud evolution and entrainment

    PubMed Central

    Narasimha, Roddam; Diwan, Sourabh Suhas; Duvvuri, Subrahmanyam; Sreenivas, K. R.; Bhat, G. S.

    2011-01-01

    Clouds are the largest source of uncertainty in climate science, and remain a weak link in modeling tropical circulation. A major challenge is to establish connections between particulate microphysics and macroscale turbulent dynamics in cumulus clouds. Here we address the issue from the latter standpoint. First we show how to create bench-scale flows that reproduce a variety of cumulus-cloud forms (including two genera and three species), and track complete cloud life cycles—e.g., from a “cauliflower” congestus to a dissipating fractus. The flow model used is a transient plume with volumetric diabatic heating scaled dynamically to simulate latent-heat release from phase changes in clouds. Laser-based diagnostics of steady plumes reveal Riehl–Malkus type protected cores. They also show that, unlike the constancy implied by early self-similar plume models, the diabatic heating raises the Taylor entrainment coefficient just above cloud base, depressing it at higher levels. This behavior is consistent with cloud-dilution rates found in recent numerical simulations of steady deep convection, and with aircraft-based observations of homogeneous mixing in clouds. In-cloud diabatic heating thus emerges as the key driver in cloud development, and could well provide a major link between microphysics and cloud-scale dynamics. PMID:21918112

  4. Low chronic ethanol consumption affects ovulation and PGE synthesis by the cumulus cell masses in mice.

    PubMed

    Cebral, E; Motta, A; de Gimeno, M F

    1999-02-01

    Central and gonadal function can be affected by chronic consumption of high and moderate doses of ethanol. Few studies have been conducted to determine the effect of ethanol intake at ovarian and gamete level. Previously, we showed that fertilization rates of low chronic ethanol treated female mice were diminished. Also, our recent results indicated that moderate chronic intake of ethanol by immature females could alter the ovulatory quantity and produce morphological alterations in the superovulated oocytes. Furthermore, PGE production by oocyte cumulus complexes (OCCs) was reduced in the females treated with 10% (w/v) ethanol. In the present investigation, we studied the effects of 5% ethanol treatment given to immature mice for 30 days on the quality and quantity of oocytes superovulated at 16 h posthuman chronic gonadotrophin. Treated females had impaired ovulation rates (P < 0.05) as compared to the controls. The percentage of activated and morphologically abnormal oocytes was elevated in the ethanol-treated females (P < 0.05). PGE synthesis by the OCCs was higher than in the controls (P < 0.01). In summary, the administration of long-term ethanol at a relatively low dose to immature females produces decreased ovulation rates, abnormal oocyte morphology with high spontaneous activation and altered levels of PGE production by the oocytes' cumulus complexes. The relationship between the oocyte quality and abnormal synthesis of PGE is discussed.

  5. Effects of cumulus parameterization closures on simulations of summer precipitation over the United States coastal oceans

    NASA Astrophysics Data System (ADS)

    Qiao, Fengxue; Liang, Xin-Zhong

    2016-06-01

    This study evaluates the effects of major cumulus parameterization closures on summer precipitation simulations over the U.S. Atlantic Coasts and Gulf of Mexico. A series of mesoscale regional climate model simulations using an Ensemble Cumulus Parameterization (ECP) that incorporates multiple alternate closure schemes into a single cloud model formulation are conducted and compared to determine the systematic errors and relative performances of individual and combined closures in capturing precipitation spatiotemporal variations. The results show that closure algorithms largely affect precipitation's geographic distribution, frequency and intensity, and diurnal cycle. The quasi-equilibrium and total instability adjustment closures simulate widespread wet biases, while the instability tendency closure produces systematic dry biases. Two closure algorithms based on the average vertical velocity at the cloud base and column moisture convergence complementarily reproduce the observed precipitation pattern and amount, and capture the frequency of heavy rainfall events better than other closures. In contrast, the instability tendency closures are better at capturing the diurnal phase but yield much larger deficits in amount. Therefore, cloud base vertical velocity and moisture convergence may be the primary factors controlling precipitation seasonal mean and daily variation, while the instability tendency may play a critical role in regulating the diurnal cycle phase.

  6. Observations of sulfur dioxide uptake and new particle formation in a midlatitude cumulus cloud

    NASA Astrophysics Data System (ADS)

    Peter, J. R.; Siems, S. T.; Jensen, J. B.; Gras, J. L.; Ishizaka, Y.; Hacker, J. M.

    2006-08-01

    Airborne measurements, obtained during the Asian Aerosol Characterisation Experiment (ACE-Asia), of SO2 and condensation nuclei (CN) concentrations were made in the local environment of a cumulus cloud band. Conserved quantities, wet equivalent potential temperature θq, and total water content Q, were used to identify the sources of air detrained on the downwind side of the cumulus band. It was found that ~65% of the detrained air originated from below cloud base and the remainder was air that had been entrained from the free troposphere upwind of the cloud and subsequently been detrained. Calculation of the sources of the detrained air parcels enabled a prediction of the concentration of SO2 and CN, assuming that SO2 and CN experienced no processing within cloud. A comparison of the predicted concentration of SO2 and CN was made with those observed. The concentration of SO2 observed was less than predicted and the amount of SO2 scavenged within cloud was calculated. The CN concentration observed was also less than predicted and, moreover, inclusion of the loss of CN to cloud droplets due to Brownian scavenging resulted in an enhanced decrease of the number concentration of CN predicted. Clear air regions around the cloud exhibited no indication of being a major source of new particles. It was concluded that new particles were formed within cloud.

  7. Microphysics, Radiation and Surface Processes in the Goddard Cumulus Ensemble (GCE) Model

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Simpson, J.; Baker, D.; Braun, S.; Chou, M.-D.; Ferrier, B.; Johnson, D.; Khain, A.; Lang, S.; Lynn, B.

    2001-01-01

    The response of cloud systems to their environment is an important link in a chain of processes responsible for monsoons, frontal depression, El Nino Southern Oscillation (ENSO) episodes and other climate variations (e.g., 30-60 day intra-seasonal oscillations). Numerical models of cloud properties provide essential insights into the interactions of clouds with each other, with their surroundings, and with land and ocean surfaces. Significant advances are currently being made in the modeling of rainfall and rain-related cloud processes, ranging in scales from the very small up to the simulation of an extensive population of raining cumulus clouds in a tropical- or midlatitude-storm environment. The Goddard Cumulus Ensemble (GCE) model is a multi-dimensional nonhydrostatic dynamic/microphysical cloud resolving model. It has been used to simulate many different mesoscale convective systems that occurred in various geographic locations. In this paper, recent GCE model improvements (microphysics, radiation and surface processes) will be described as well as their impact on the development of precipitation events from various geographic locations. The performance of these new physical processes will be examined by comparing the model results with observations. In addition, the explicit interactive processes between cloud, radiation and surface processes will be discussed.

  8. Analysis and Numerical Simulation of Humidity Halos around Trade Wind Cumulus Clouds

    NASA Astrophysics Data System (ADS)

    Lu, M.; Wang, J.; Freedman, A.; Jonsson, H. H.; Flagan, R. C.; McClatchey, R. A.; Seinfeld, J. H.

    2002-12-01

    Significant enhancements in humidity above that in the cloud-free atmosphere have been found in the vicinity of isolated cumulus clouds, so-called cloud halos. Cloud halos can reflect features of cloud evolution, increase shortwave atmospheric radiative absorption, and may serve as a predominant region of new particle formation. We report results of an aircraft campaign off Oahu, Hawaii during August 2001, aimed at characterizing the humidity properties around isolated cumulus clouds at 10 m spatial resolution by a novel high-speed spectroscopic water vapor concentration monitor developed by Aerodyne Research, Inc. Analysis of the measurements adds to the existing body of information on cloud halos, their frequency of occurrence, spatial extent, and meteorological characteristics. The dynamic model RAMS (Regional Atmospheric Modeling System) in the LES (Large Eddy Simulation) mode and the SHDOM (Spherical Harmonic Discrete Ordinate Method) radiative transfer model have been implemented for one particularly long-lived cloud to track the temporal evolution of the cloud halos and to calculate the associated spatial and temporal patterns of shortwave absorption. Results of this modeling study are in general agreement with the field measurement data and previous aircraft studies.

  9. Stress Induced Mechano-electrical Writing-Reading of Polymer Film Powered by Contact Electrification Mechanism

    PubMed Central

    Goswami, Sumita; Nandy, Suman; Calmeiro, Tomás R.; Igreja, Rui; Martins, Rodrigo; Fortunato, Elvira

    2016-01-01

    Mechano-electrical writing and reading in polyaniline (PANI) thin film are demonstrated via metal-polymer contact electrification mechanism (CEM). An innovative conception for a non-destructive self-powered writable-readable data sheet is presented which can pave the way towards new type of stress induced current harvesting devices. A localized forced deformation of the interface has been enacted by pressing the atomic force microscopic probe against the polymer surface, allowing charge transfer between materials interfaces. The process yields a well-defined charge pattern by transmuting mechanical stress in to readable information. The average of output current increment has been influenced from 0.5 nA to 15 nA for the applied force of 2 nN to 14 nN instead of electrical bias. These results underscore the importance of stress-induced current harvesting mechanism and could be scaled up for charge patterning of polymer surface to writable-readable data sheet. Time evolutional current distribution (TECD) study of the stress-induced patterned PANI surface shows the response of readability of the recorded data with time. PMID:26786701

  10. Field performance of lead-acid batteries in photovoltaic rural electrification kits

    SciTech Connect

    Huacuz, J.M.; Flores, R.; Agredano, J.; Munguia, G.

    1995-12-31

    A field survey was carried out in 83 rural communities within seven different states in Mexico, to assess the performance of photovoltaic (PV) rural electrification systems previously installed and to sense the degree of user satisfaction with PV technology. The present work reports on the performance of lead-acid batteries associated with domestic PV lighting kits. A sample of 555 batteries, from a total of 2512 PV kits installed in the region of study at the time of the survey, was randomly taken for analysis. Batteries were rated using a semiquantitative methodology developed at the Electrical Research Institute of Mexico (IIE). Results obtained from the survey are on the positive side, meaning that car-type batteries (representing 87% of the sample) perform reasonably well as part of PV lighting kits. However, there may be reasons for concern. A number of factors of technical, environmental and socio cultural nature, can negatively influence the performance of batteries in the field. Results from the survey show that undersized storage capacity is one of the main technical factors contributing to a rapid decrease in battery performance. However, improper operation and maintenance practices, derived from socio cultural factors and a lack of proper user training, are important recurring elements that may result in battery lifes shorter than anticipated. 18 refs., 8 figs., 3 tabs.

  11. Solar-Based Rural Electrification and Micro-Enterprise Development in Latin America: A Gender Analysis

    SciTech Connect

    Smith, J.

    2000-11-16

    Worldwide, an estimated 1.5 to 2 billion people do not have access to electricity, including 100 million in the Latin America region. Depending on the country, 30 to 90% of this unelectrified Latin American population lives in rural areas where geographic remoteness and low energy consumption patterns may preclude the extension of the conventional electricity grid. Women are heavily impacted by the energy scarcity given their role as primary energy procurers and users for the household, agricultural and small industrial subsectors in developing countries. As a result, women spend disproportionately more time engaged in energy-related activities like carrying water and searching for cooking fuel. This paper describes the use of decentralized renewable energy systems as one approach to meet the energy needs of rural areas in Latin America. It outlines the advantages of a decentralized energy paradigm to achieve international development goals, especially as they relate to women. The paper studies Enersol Associates, Inc.'s Solar-Based Rural Electrification model as an example of a decentralized energy program which has merged energy and development needs through the local involvement of energy entrepreneurs, non-governmental organizations and community members.

  12. Deep carbon reductions in California require electrification and integration across economic sectors

    NASA Astrophysics Data System (ADS)

    Wei, Max; Nelson, James H.; Greenblatt, Jeffery B.; Mileva, Ana; Johnston, Josiah; Ting, Michael; Yang, Christopher; Jones, Chris; McMahon, James E.; Kammen, Daniel M.

    2013-03-01

    Meeting a greenhouse gas (GHG) reduction target of 80% below 1990 levels in the year 2050 requires detailed long-term planning due to complexity, inertia, and path dependency in the energy system. A detailed investigation of supply and demand alternatives is conducted to assess requirements for future California energy systems that can meet the 2050 GHG target. Two components are developed here that build novel analytic capacity and extend previous studies: (1) detailed bottom-up projections of energy demand across the building, industry and transportation sectors; and (2) a high-resolution variable renewable resource capacity planning model (SWITCH) that minimizes the cost of electricity while meeting GHG policy goals in the 2050 timeframe. Multiple pathways exist to a low-GHG future, all involving increased efficiency, electrification, and a dramatic shift from fossil fuels to low-GHG energy. The electricity system is found to have a diverse, cost-effective set of options that meet aggressive GHG reduction targets. This conclusion holds even with increased demand from transportation and heating, but the optimal levels of wind and solar deployment depend on the temporal characteristics of the resulting load profile. Long-term policy support is found to be a key missing element for the successful attainment of the 2050 GHG target in California.

  13. Electrification of the transportation sector offers limited country-wide greenhouse gas reductions

    NASA Astrophysics Data System (ADS)

    Meinrenken, Christoph J.; Lackner, Klaus S.

    2014-03-01

    Compared with conventional propulsion, plugin and hybrid vehicles may offer reductions in greenhouse gas (GHG) emissions, regional air/noise pollution, petroleum dependence, and ownership cost. Comparing only plugins and hybrids amongst themselves, and focusing on GHG, relative merits of different options have been shown to be more nuanced, depending on grid-carbon-intensity, range and thus battery manufacturing and weight, and trip patterns. We present a life-cycle framework to compare GHG emissions for three drivetrains (plugin-electricity-only, gasoline-only-hybrid, and plugin-hybrid) across driving ranges and grid-carbon-intensities, for passenger cars, vans, buses, or trucks (well-to-wheel plus storage manufacturing). Parameter and model uncertainties are quantified via sensitivity analyses. We find that owing to the interplay of range, GHG/km, and portions of country-wide kms accessible to electrification, GHG reductions achievable from plugins (whether electricity-only or hybrids) are limited even when assuming low-carbon future grids. Furthermore, for policy makers considering GHG from electricity and transportation sectors combined, plugin technology may in fact increase GHG compared to gasoline-only-hybrids, regardless of grid-carbon-intensity.

  14. Relations of Kinematics, Microphysics and Electrification in an Isolated Mountain Thunderstorm.

    NASA Astrophysics Data System (ADS)

    Ziegler, Conrad L.; Ray, Peter S.; Macgorman, Donald R.

    1986-10-01

    This paper addresses aspects of the airflow, microphysics, and electrification in a mountain thunderstorm which occurred on 7 August 1979 over the Langmuir Laboratory new Socorro, New Mexico, site of the Thunderstorm Research International Program (TRIP). Single Doppler observations are used to form a conceptual model of the essentially one-dimensional storm updraft which is expressed in simple analytical form. A one-dimensional kinematic numerical cloud model is employed with the analytic updraft profile to diagnose the evolution of temperature, war substance, radar reflectivity, space charge density and axial electric field in the main updraft region. Retrieved thermal, microphysical, and electrical variables are verified with in situ aircraft and balloon observations and measured radar reflectivity. The calculated rate of noninductive charge transfer accompanying collision and separation of ice crystals and riming graupel particles is in direct proportion to cloud and precipitation content, and attains a peak value of about 10 C km3 min1 between 30° and 40°C. Agreement between calculations and balloon measurements of space charge density and vertical electric field imply that the noninductive graupel-ice charge separation mechanism accounts for a substantial portion of the storm's total separated charge. The peak noninductive charging rate appears to balance the discharge rate implied by the observed flash rate.

  15. Potential for widespread electrification of personal vehicle travel in the United States

    NASA Astrophysics Data System (ADS)

    Needell, Zachary A.; McNerney, James; Chang, Michael T.; Trancik, Jessika E.

    2016-09-01

    Electric vehicles can contribute to climate change mitigation if coupled with decarbonized electricity, but only if vehicle range matches travellers’ needs. Evaluating electric vehicle range against a population’s needs is challenging because detailed driving behaviour must be taken into account. Here we develop a model to combine information from coarse-grained but expansive travel surveys with high-resolution GPS data to estimate the energy requirements of personal vehicle trips across the US. We find that the energy requirements of 87% of vehicle-days could be met by an existing, affordable electric vehicle. This percentage is markedly similar across diverse cities, even when per capita gasoline consumption differs significantly. We also find that for the highest-energy days, other vehicle technologies are likely to be needed even as batteries improve and charging infrastructure expands. Car sharing or other means to serve this small number of high-energy days could play an important role in the electrification and decarbonization of transportation.

  16. Electrification in winter storms and the analysis of thunderstorm overflight data

    NASA Technical Reports Server (NTRS)

    Brook, Marx

    1993-01-01

    We have been focusing our study of electrification in winter storms on the lightning initiation process, making inferences about the magnitude of the electric fields from the initial pulses associated with breakdown, i.e., with the formation of the initial streamers. The essence of the most significant finding is as follows: (1) initial breakdown radiation pulses from stepped leaders prior to the first return stroke are very large, reaching values of 20-30 Volts/meter, comparable to return stroke radiation; and (2) the duration of the stepped leader, from the initial detectable radiation pulse to the return stroke onset, is very-short-ranging from a minimum 1.5 ms to a maximum of 4.5 ms. This past summer (June-August of 1991) we participated in the CAPE program at the Kennedy Space Center in order to acquire data on stepped leaders in summer storms with the same equipment used to get the winter storm data. We discovered that the vigorous leaders seen in winter so frequently were present in summer storms, although not as large in amplitude and certainly not as frequent.

  17. Assessment of the Electrification of the Road Transport Sector on Net System Emissions

    NASA Astrophysics Data System (ADS)

    Miller, James

    As worldwide environmental consciousness grows, electric vehicles (EVs) are becoming more common and despite the incredible potential for emissions reduction, the net emissions of the power system supply side plus the transportation system are dependent on the generation matrix. Current EV charging patterns tend to correspond directly with the peak consumption hours and have the potential to increase demand sharply allowing for only a small penetration of Electric Vehicles. Using the National Household Travel Survey (NHTS) data a model is created for vehicle travel patterns using trip chaining. Charging schemes are modeled to include uncontrolled residential, uncontrolled residential/industrial charging, optimized charging and optimized charging with vehicle to grid discharging. A charging profile is then determined based upon the assumption that electric vehicles would directly replace a percentage of standard petroleum-fueled vehicles in a known system. Using the generation profile for the specified region, a unit commitment model is created to establish not only the generation dispatch, but also the net CO2 profile for variable EV penetrations and charging profiles. This model is then used to assess the impact of the electrification of the road transport sector on the system net emissions.

  18. Stress Induced Mechano-electrical Writing-Reading of Polymer Film Powered by Contact Electrification Mechanism

    NASA Astrophysics Data System (ADS)

    Goswami, Sumita; Nandy, Suman; Calmeiro, Tomás R.; Igreja, Rui; Martins, Rodrigo; Fortunato, Elvira

    2016-01-01

    Mechano-electrical writing and reading in polyaniline (PANI) thin film are demonstrated via metal-polymer contact electrification mechanism (CEM). An innovative conception for a non-destructive self-powered writable-readable data sheet is presented which can pave the way towards new type of stress induced current harvesting devices. A localized forced deformation of the interface has been enacted by pressing the atomic force microscopic probe against the polymer surface, allowing charge transfer between materials interfaces. The process yields a well-defined charge pattern by transmuting mechanical stress in to readable information. The average of output current increment has been influenced from 0.5 nA to 15 nA for the applied force of 2 nN to 14 nN instead of electrical bias. These results underscore the importance of stress-induced current harvesting mechanism and could be scaled up for charge patterning of polymer surface to writable-readable data sheet. Time evolutional current distribution (TECD) study of the stress-induced patterned PANI surface shows the response of readability of the recorded data with time.

  19. Atmospheric Electrification in Dusty, Reactive Gases in the Solar System and Beyond

    NASA Astrophysics Data System (ADS)

    Helling, Christiane; Harrison, R. Giles; Honary, Farideh; Diver, Declan A.; Aplin, Karen; Dobbs-Dixon, Ian; Ebert, Ute; Inutsuka, Shu-ichiro; Gordillo-Vazquez, Francisco J.; Littlefair, Stuart

    2016-07-01

    Detailed observations of the solar system planets reveal a wide variety of local atmospheric conditions. Astronomical observations have revealed a variety of extrasolar planets none of which resembles any of the solar system planets in full. Instead, the most massive amongst the extrasolar planets, the gas giants, appear very similar to the class of (young) brown dwarfs which are amongst the oldest objects in the Universe. Despite this diversity, solar system planets, extrasolar planets and brown dwarfs have broadly similar global temperatures between 300 and 2500 K. In consequence, clouds of different chemical species form in their atmospheres. While the details of these clouds differ, the fundamental physical processes are the same. Further to this, all these objects were observed to produce radio and X-ray emissions. While both kinds of radiation are well studied on Earth and to a lesser extent on the solar system planets, the occurrence of emissions that potentially originate from accelerated electrons on brown dwarfs, extrasolar planets and protoplanetary disks is not well understood yet. This paper offers an interdisciplinary view on electrification processes and their feedback on their hosting environment in meteorology, volcanology, planetology and research on extrasolar planets and planet formation.

  20. Contact Electrification of Individual Dielectric Microparticles Measured by Optical Tweezers in Air.

    PubMed

    Park, Haesung; LeBrun, Thomas W

    2016-12-21

    We measure charging of single dielectric microparticles after interaction with a glass substrate using optical tweezers to control the particle, measure its charge with a sensitivity of a few electrons, and precisely contact the particle with the substrate. Polystyrene (PS) microparticles adhered to the substrate can be selected based on size, shape, or optical properties and repeatedly loaded into the optical trap using a piezoelectric (PZT) transducer. Separation from the substrate leads to charge transfer through contact electrification. The charge on the trapped microparticles is measured from the response of the particle motion to a step excitation of a uniform electric field. The particle is then placed onto a target location of the substrate in a controlled manner. Thus, the triboelectric charging profile of the selected PS microparticle can be measured and controlled through repeated cycles of trap loading followed by charge measurement. Reversible optical trap loading and manipulation of the selected particle leads to new capabilities to study and control successive and small changes in surface interactions.

  1. Relationship between thunderstorm electrification and storm kinetics revealed by phased array weather radar

    NASA Astrophysics Data System (ADS)

    Yoshida, S.; Adachi, T.; Kusunoki, K.; Hayashi, S.; Wu, T.; Ushio, T.; Yoshikawa, E.

    2017-04-01

    We examine 3-D lightning location data and radar data obtained through multiple radar observation stations, including two X-band phased array weather radars (PAWRs), in order to understand the relationship between thunderstorm electrification and storm kinetics. In an investigated convective cell, both intracloud (IC) and cloud-to-ground (CG) flash rates drastically change within 25 min. First, the IC flash rate shows a steep increase with a peak at 10 min-1, and then, the CG flash rate peaks 7 min afterward. During the increase phase of the IC flash rate, the radar observation indicates that the echo top height and updraft echo volume in the upper level increase. The upper positive charge regions removed by IC flashes are located in or near the updraft region at high altitudes. On the contrary, the IC flash rate decreases when the updraft at high altitudes weakens. The IC flash rate is well correlated with a proxy for updraft volume in 1 min interval comparison. These results indicate that the IC flash rate has a strong connection with updraft at high altitudes. The CG flash rate peaks when precipitation particles, probably involving graupel, from high altitudes arrive at approximately the -10°C isotherm level. We speculate that graupel from high altitudes might contribute to the initiations of CG flashes. We show an abrupt ascent of the upper positive charge region involved in IC flashes. PAWR observation results indicate that the updraft might have contributed to the ascent of the upper positive lightning charge region.

  2. Relations of kinematics, microphysics and electrification in an isolated mountain thunderstorm

    SciTech Connect

    Ziegler, C.L.; Ray, P.S.; MacGorman, D.R.

    1986-10-01

    This paper addresses aspects of the airflow, microphysics, and electrification in a mountain thunderstorm which occurred on 7 August 1979 over the Langmuir Laboratory near Socorro, New Mexico, site of the Thunderst Research International Program (TRIP). Single Doppler observations are used to form a conceptual model of the essentially one-dimensional storm nematic numerical cloud model is employed with the analytic updraft profile to diagnose the evolution of temperature, water substance, radar reflectivity, space charge density and axial electric field in the main updraft region. Retrieved thermal, microphysical, and electrical variabiles are verified with in situ aircraft and balloon observations and measured radar reflectivity. The calculated ing graupel particles is in a direct proportion to cloud and precipitation content, and attains a peak value of about 10 C km/sup -3/ min/sup -1/ between -30/sup 0/ and -40/sup 0/C. and vertical electric field imply that the noninductive graupel-ice charge separation mechanism accounts for a substantial portion of the storm's total separated charge. The peak noninductive charging rate appears to balance the discharge rate implied by the observed flash rate.

  3. Down-regulation of the CYP19A1 gene in cumulus cells of infertile women with endometriosis.

    PubMed

    Barcelos, Ionara Diniz E S; Donabella, Flávia Capello; Ribas, Cristiana Padovan; Meola, Juliana; Ferriani, Rui Alberto; de Paz, Cláudia Cristina Paro; Navarro, Paula A

    2015-05-01

    Aromatase plays a fundamental role in the establishment of oocyte quality, which might be compromised in infertile women with endometriosis. The expression of the CYP19A1 gene (that encodes aromatase) was compared in cumulus cells and oestradiol concentrations in the follicular fluid of infertile women with and without endometriosis submitted to ovarian stimulation for intracytoplasmic sperm injection. Cumulus cells were isolated and the expression of the CYP19A1 was quantitated through real-time polymerase chain reaction. Oestradiol concentrations in follicular fluid were measured by chemiluminescence immunoassay. A lower expression of the CYP19A1 in the cumulus cells of infertile women with endometriosis was observed compared with controls (0.17 ± 0.13 and 0.56 ± 0.12, respectively), and no significant difference in the follicular fluid oestradiol concentrations was observed between groups. Our results show reduced expression of the CYP19A1 in cumulus cells of infertile women with endometriosis, which may play a role in the pathogenesis of endometriosis-related infertility.

  4. The Effect of Cumulus Cloud Field Anisotropy on Domain-Averaged Solar Fluxes and Atmospheric Heating Rates

    SciTech Connect

    Hinkelman, Laura M.; Evans, K. Franklin; Clothiaux, Eugene E.; Ackerman, Thomas P.; Stackhouse, Paul W.

    2007-10-01

    Cumulus clouds can become tilted or elongated in the presence of wind shear. Nevertheless, most studies of the interaction of cumulus clouds and radiation have assumed these clouds to be isotropic. This paper describes an investigation of the effect of fair-weather cumulus cloud field anisotropy on domain-averaged solar fluxes and atmospheric heating rate profiles. A stochastic field generation algorithm was used to produce 20 three-dimensional liquid water content fields based on the statistical properties of cloud scenes from a large eddy simulation. Progressively greater degrees of x–z plane tilting and horizontal stretching were imposed on each of these scenes, so that an ensemble of scenes was produced for each level of distortion. The resulting scenes were used as input to a three-dimensional Monte Carlo radiative transfer model. Domain-averaged transmission, reflection, and absorption of broadband solar radiation were computed for each scene along with the average heating rate profile. Both tilt and horizontal stretching were found to significantly affect calculated fluxes, with the amount and sign of flux differences depending strongly on sun position relative to cloud distortion geometry. The mechanisms by which anisotropy interacts with solar fluxes were investigated by comparisons to independent pixel approximation and tilted independent pixel approximation computations for the same scenes. Finally, cumulus anisotropy was found to most strongly impact solar radiative transfer by changing the effective cloud fraction (i.e., the cloud fraction with respect to the solar beam direction).

  5. A statistically based cumulus parameterization scheme that makes use of heating and moistening rates derived from observations

    NASA Astrophysics Data System (ADS)

    Misra, Vasubandhu

    1997-10-01

    A cumulus parameterization scheme whose vertical distribution of heating and drying are based on observations is developed. A rotated principal component (RPC) analysis performed on these observations of convective heating and apparent drying profiles reveal, that the first three principle components (PC's) explain most of the variance. This supports the concept of cumulus parameterization. By retaining these principal components, and developing statistically based multiple linear regression equations to estimate the principal component scores which quantifies the relative contribution of each PC towards the final profile, a robust cumulus parameterization scheme is conceived. Diagnostic cross validation tests of the cumulus parameterization, indicate that the retrieved profiles of heating and drying match very closely with the observed. Prognostic studies were performed using the Florida State University Global Spectral Model at three different resolutions of T42, T106 and T170. At all three resolutions the new cumulus parameterization scheme showed a superior performance in the forecast of rainfall, wind circulation and surface pressure over the control model which had the modified Kuo of Krishnamurti et al. (1983) as its convection scheme. In light of the high resolution experiments conducted at horizontal resolution of T-170, the concept of 'organization of convection' is further explored in terms of the implied energetics. The forecasts at horizontal resolution of T- 170 indicated that the intensity of Hurricane Andrew is explained best from the model which contains the new cumulus parameterization scheme proposed here. This model resolves the most mesoconvective elements relative to the control model which is discerned by the rainfall maximas embedded in an envelope of stratiform like broad scale precipitation. A physical initialization using the new cumulus parameterization scheme is also implemented in the FSUGSM. Forecasts from physically initialized

  6. Clustering, randomness, and regularity in cloud fields: 2. Cumulus cloud fields

    NASA Astrophysics Data System (ADS)

    Zhu, T.; Lee, J.; Weger, R. C.; Welch, R. M.

    1992-12-01

    During the last decade a major controversy has been brewing concerning the proper characterization of cumulus convection. The prevailing view has been that cumulus clouds form in clusters, in which cloud spacing is closer than that found for the overall cloud field and which maintains its identity over many cloud lifetimes. This "mutual protection hypothesis" of Randall and Huffman (1980) has been challenged by the "inhibition hypothesis" of Ramirez et al. (1990) which strongly suggests that the spatial distribution of cumuli must tend toward a regular distribution. A dilemma has resulted because observations have been reported to support both hypotheses. The present work reports a detailed analysis of cumulus cloud field spatial distributions based upon Landsat, Advanced Very High Resolution Radiometer, and Skylab data. Both nearest-neighbor and point-to-cloud cumulative distribution function statistics are investigated. The results show unequivocally that when both large and small clouds are included in the cloud field distribution, the cloud field always has a strong clustering signal. The strength of clustering is largest at cloud diameters of about 200-300 m, diminishing with increasing cloud diameter. In many cases, clusters of small clouds are found which are not closely associated with large clouds. As the small clouds are eliminated from consideration, the cloud field typically tends towards regularity. Thus it would appear that the "inhibition hypothesis" of Ramirez and Bras (1990) has been verified for the large clouds. However, these results are based upon the analysis of point processes. A more exact analysis also is made which takes into account the cloud size distributions. Since distinct clouds are by definition nonoverlapping, cloud size effects place a restriction upon the possible locations of clouds in the cloud field. The net effect of this analysis is that the large clouds appear to be randomly distributed, with only weak tendencies towards

  7. The apoptotic profile of human cumulus cells changes with patient age and after exposure to sperm but not in relation to oocyte maturity.

    PubMed

    Moffatt, Odette; Drury, Sarah; Tomlinson, Matthew; Afnan, Masoud; Sakkas, Denny

    2002-05-01

    To determine the expression of apoptosis-associated molecules on cumulus cells removed from individual oocytes of different maturity, inseminated oocytes and to investigate the possibility of an age-dependent expression. Analysis of apoptosis in cumulus cells isolated from oocytes of different stages of maturity. Assisted reproductive technology program of the Birmingham Women's Hospital, Birmingham, UK. Patients undergoing intracytoplasmic sperm injection or IVF cycles. Percentage of positive cumulus cells when assessed for nuclear DNA damage using the terminal deoxyuridine nucleotide end-labeling assay or stained with antibodies [Fas, Fas ligand, the antiapoptotic protein Bcl-xl, and the RNA-binding protein (TIAR)]. Cumulus cells collected from mature oocytes showed no significant difference in the percentage of apoptotic markers compared to those recovered from immature oocytes, whereas those from patients >/=38 years differed significantly. When cumulus cells were exposed to sperm the levels of apoptotic markers altered significantly from those not exposed to sperm. The results show that the cumulus cells of human oocytes are equipped with a mechanism to undergo apoptosis and that patient age and the exposure of cumulus cells to sperm can alter their profiles of apoptotic markers.

  8. Embryonic Poly(A)-Binding Protein (EPAB) Is Required for Granulosa Cell EGF Signaling and Cumulus Expansion in Female Mice

    PubMed Central

    Yang, Cai-Rong; Lowther, Katie M.; Lalioti, Maria D.

    2016-01-01

    Embryonic poly(A)-binding protein (EPAB) is the predominant poly(A)-binding protein in Xenopus, mouse, and human oocytes and early embryos before zygotic genome activation. EPAB is required for translational activation of maternally stored mRNAs in the oocyte and Epab−/− female mice are infertile due to impaired oocyte maturation, cumulus expansion, and ovulation. The aim of this study was to characterize the mechanism of follicular somatic cell dysfunction in Epab−/− mice. Using a coculture system of oocytectomized cumulus oophorus complexes (OOXs) with denuded oocytes, we found that when wild-type OOXs were cocultured with Epab−/− oocytes, or when Epab−/− OOXs were cocultured with WT oocytes, cumulus expansion failed to occur in response to epidermal growth factor (EGF). This finding suggests that oocytes and cumulus cells (CCs) from Epab−/− mice fail to send and receive the necessary signals required for cumulus expansion. The abnormalities in Epab−/− CCs are not due to lower expression of the oocyte-derived factors growth differentiation factor 9 or bone morphogenetic protein 15, because Epab−/− oocytes express these proteins at comparable levels with WT. Epab−/− granulosa cells (GCs) exhibit decreased levels of phosphorylated MEK1/2, ERK1/2, and p90 ribosomal S6 kinase in response to lutenizing hormone and EGF treatment, as well as decreased phosphorylation of the EGF receptor. In conclusion, EPAB, which is oocyte specific, is required for the ability of CCs and GCs to become responsive to LH and EGF signaling. These results emphasize the importance of oocyte-somatic communication for GC and CC function. PMID:26492470

  9. Inhibitors of zinc-dependent metalloproteases hinder sperm passage through the cumulus oophorus during porcine fertilization in vitro.

    PubMed

    Beek, J; Nauwynck, H; Maes, D; Van Soom, A

    2012-12-01

    In this study, we report for the first time on a possible contribution of metalloproteases in sperm passage through the cumulus matrix in pigs. The presence of 20 μM 1,10-phenanthroline (1,10-PHEN), inhibitor of zinc-dependent metalloproteases, strongly inhibited the degree of sperm penetration in cumulus-intact (CI), but not in cumulus-free (CF), porcine oocytes during IVF. The inhibitory effect of 1,10-PHEN was due to the chelation of metal ions as a non-chelating analog (1,7-PHEN) did not affect IVF rates. Furthermore, incubation with 1,10-PHEN did not affect sperm binding to the zona pellucida nor sperm motility, membrane integrity, or acrosomal status. These findings led to the assumption that 1,10-PHEN interacts with a sperm- or cumulus-derived metalloprotease. Metalloproteases are key players in physiological processes involving degradation or remodeling of extracellular matrix. In vivo, their proteolytic activity is regulated by tissue inhibitors of metalloproteases (TIMP1-TIMP4). We tested the effect of TIMP3 on fertilization parameters after porcine IVF. Similar to 1,10-PHEN, TIMP3 inhibited total fertilization rate of CI but not CF oocytes and did not influence sperm quality parameters. Although the inhibitory effect was stronger in CI oocytes, TIMP3 also reduced the degree of sperm penetration in CF oocytes, suggesting the involvement of a metalloprotease in a subsequent step during fertilization. In conclusion, our results indicate the involvement of TIMP3-sensitive, zinc-dependent metalloprotease activity in sperm passage through the cumulus oophorus in pigs. The results should provide the basis for further biochemical research toward the localization and identification of the metalloprotease involved.

  10. Human sperm acrosome reaction-initiating activity associated with the human cumulus oophorus and mural granulosa cells.

    PubMed

    Siiteri, J E; Dandekar, P; Meizel, S

    1988-04-01

    This report describes the detection and partial characterization of preovulatory human cumulus oophorus and mural granulosa cell-associated activity capable of initiating the human sperm acrosome reaction (AR) in vitro. Fragments of preovulatory human cumulus (cells plus extracellular matrix) were washed 3 times, incubated for 24 hr and the spent media and washes assayed for their ability to initiate the human sperm acrosome reaction (AR) in vitro. AR activity was present in the first two washes but not the third wash; however, AR activity was recovered in the spent medium after 3 X-washed fragments were incubated for 24 hr under conditions which maintained the viability of the cumulus cells. The spent media of preovulatory human mural granulosa cells contained AR-initiating activity after 1-3, 3-6, and 6-9 days of culture. The properties of the AR activity present in spent media of human cumulus fragments included resistance to loss of activity during treatment with pronase; resistance to loss of activity during treatment with chondroitinase ABC or bacterial hyaluronidase; heat stability after overnight incubation; lack of extraction by chloroform-methanol; an apparent molecular weight (MW) of 50,000, as determined by Sephadex G-75 column chromatography; conversion to a lower apparent MW activity by incubation with pronase. These properties are also characteristic of a fraction derived by Sephadex G-75 chromatography of preovulatory human follicular fluid which also has been shown to stimulate the human sperm acrosome reaction in vitro. The AR activity from spent media of human mural granulosa cells is also found in a 50,000 MW Sephadex G-75 fraction. We propose that the sources of the 50,000 MW human follicular fluid AR activity are the cumulus oophorus and the mural granulosa cells.

  11. Follicle-stimulating hormone-induced rescue of cumulus cell apoptosis and enhanced development ability of buffalo oocytes.

    PubMed

    Jain, A; Jain, T; Kumar, P; Kumar, M; De, S; Gohain, M; Kumar, R; Datta, T K

    2016-04-01

    The effect of follicle-stimulating hormone (FSH) on apoptotic status of cumulus cells, expression of proapoptotic and antiapoptotic genes, and development rate of in vitro fertilization-produced buffalo embryos were investigated. FSH supplementation in in vitro maturation-medium resulted in a dose-dependent reduction in the expression of proapoptotic genes namely, BCL2-associated X protein (BAX), cytochrome c, and caspase-3 and increase in the expression of antiapoptotic genes such as B-cell lymphoma 2 (BCL2) and X-linked inhibitor of apoptosis protein (XIAP) in cumulus cells of mature oocyte. Cumulus expansion, oocyte maturation, cleavage, and blastocyst development rates were significantly higher (P < 0.05) in 5 and 10-μg/mL FSH-supplemented groups as compared with control. Significant increase in the expression of FSH receptor messenger RNA was also found with 5 and 10-μg/mL FSH (P < 0.05). Terminal deoxynucleotidyl transferase dUTP nick end labeling assay confirmed that the population of apoptotic cumulus cells of matured oocytes was reduced in the FSH-treated groups as compared with control (P < 0.05). In conclusion, our data suggest that FSH may attenuate apoptosis in cumulus cells via mitochondria-dependent apoptotic pathway by increasing XIAP expression, resulting in a more favorable ratio of BCL2/BAX expression and decreasing the cytochrome c and caspase-3 expression, eventually contributing to developmental competence of oocytes. The information generated will help in improving the in vitro embryo production program in buffalo.

  12. Expression and cellular distribution of estrogen and progesterone receptors and the real-time proliferation of porcine cumulus cells.

    PubMed

    Kempisty, Bartosz; Ziółkowska, Agnieszka; Ciesiółka, Sylwia; Piotrowska, Hanna; Antosik, Paweł; Bukowska, Dorota; Brüssow, Klaus P; Nowicki, Michał; Zabel, Maciej

    2015-12-01

    Although the expression of estrogen and progesterone receptors within porcine ovary and cumulus-oocyte complexes (COCs) is well recognized, still little information is known regarding expression of the progesterone receptor (PGR), PGR membrane component 1 (PGRMC1) and of estrogen-related receptors (ERRγ and ERRβ/γ) in separated cumulus cells in relation to real-time proliferation. In this study, a model of oocytes-separated cumulus cells was used to analyze the cell proliferation index and the expression PGR, PGRMC1 and of ERRγ and ERRβ/γ during 96-h cultivation in vitro using real-time quantitative PCR (qRT-PCR) and confocal microscopic observation. We found that PGR protein expression was increased at 0 h, compared with PGR protein expression after 96 h of culture (P < 0.001). The expression of PGRMC1, ERRγ and ERRβ/γ was unchanged. After using qRT-PCR we did not found statistical differences in expression of PGR, PGRMC1, ERRγ and ERRβ/γ during 96 h of cumulus cells in vitro culture (IVC). We supposed that the differential expression of the PGR protein at 0 h and after 96 h is related to a time-dependent down-regulation, which may activate a negative feedback. The distribution of PGR, PGRMC1 proteins may be linked with the translocation of receptors to the cytoplasm after the membrane binding of respective agonists and intra-cytoplasmic signal transduction. Furthermore, cumulus cells analyzed at 0 h were characterized by decreased proliferation index, whereas those after 96 h of culture revealed a significant increase of proliferation index, which may be associated with differentiation/luteinization of these cells during real-time proliferation.

  13. Embryonic Poly(A)-Binding Protein (EPAB) Is Required for Granulosa Cell EGF Signaling and Cumulus Expansion in Female Mice.

    PubMed

    Yang, Cai-Rong; Lowther, Katie M; Lalioti, Maria D; Seli, Emre

    2016-01-01

    Embryonic poly(A)-binding protein (EPAB) is the predominant poly(A)-binding protein in Xenopus, mouse, and human oocytes and early embryos before zygotic genome activation. EPAB is required for translational activation of maternally stored mRNAs in the oocyte and Epab(-/-) female mice are infertile due to impaired oocyte maturation, cumulus expansion, and ovulation. The aim of this study was to characterize the mechanism of follicular somatic cell dysfunction in Epab(-/-) mice. Using a coculture system of oocytectomized cumulus oophorus complexes (OOXs) with denuded oocytes, we found that when wild-type OOXs were cocultured with Epab(-/-) oocytes, or when Epab(-/-) OOXs were cocultured with WT oocytes, cumulus expansion failed to occur in response to epidermal growth factor (EGF). This finding suggests that oocytes and cumulus cells (CCs) from Epab(-/-) mice fail to send and receive the necessary signals required for cumulus expansion. The abnormalities in Epab(-/-) CCs are not due to lower expression of the oocyte-derived factors growth differentiation factor 9 or bone morphogenetic protein 15, because Epab(-/-) oocytes express these proteins at comparable levels with WT. Epab(-/-) granulosa cells (GCs) exhibit decreased levels of phosphorylated MEK1/2, ERK1/2, and p90 ribosomal S6 kinase in response to lutenizing hormone and EGF treatment, as well as decreased phosphorylation of the EGF receptor. In conclusion, EPAB, which is oocyte specific, is required for the ability of CCs and GCs to become responsive to LH and EGF signaling. These results emphasize the importance of oocyte-somatic communication for GC and CC function.

  14. Functional role of the bovine oocyte-specific protein JY-1 in meiotic maturation, cumulus expansion, and subsequent embryonic development.

    PubMed

    Lee, Kyung-Bon; Wee, Gabbine; Zhang, Kun; Folger, Joseph K; Knott, Jason G; Smith, George W

    2014-03-01

    Oocyte-expressed genes regulate key aspects of ovarian follicular development and early embryogenesis. We previously demonstrated a requirement of the oocyte-specific protein JY-1 for bovine early embryogenesis. Given that JY-1 is present in oocytes throughout folliculogenesis, and oocyte-derived JY-1 mRNA is temporally regulated postfertilization, we hypothesized that JY-1 levels in oocytes impact nuclear maturation and subsequent early embryogenesis. A novel model system, whereby JY-1 small interfering RNA was microinjected into cumulus-enclosed germinal vesicle-stage oocytes and meiotic arrest maintained for 48 h prior to in vitro maturation (IVM), was validated and used to determine the effect of reduced oocyte JY-1 expression on nuclear maturation, cumulus expansion, and embryonic development after in vitro fertilization. Depletion of JY-1 protein during IVM effectively reduced cumulus expansion, percentage of oocytes progressing to metaphase II, proportion of embryos that cleaved early, total cleavage rates and development to 8- to 16-cell stage, and totally blocked development to the blastocyst stage relative to controls. Supplementation with JY-1 protein during oocyte culture rescued effects of JY-1 depletion on meiotic maturation, cumulus expansion, and early cleavage, but did not rescue development to 8- to 16-cell and blastocyst stages. However, effects of JY-1 depletion postfertilization on development to 8- to 16-cell and blastocyst stages were rescued by JY-1 supplementation during embryo culture. In conclusion, these results support an important functional role for oocyte-derived JY-1 protein during meiotic maturation in promoting progression to metaphase II, cumulus expansion, and subsequent embryonic development.

  15. Multiscale assessment of progress of electrification in Indonesia based on brightness level derived from nighttime satellite imagery.

    PubMed

    Ramdani, Fatwa; Setiani, Putri

    2017-06-01

    Availability of electricity can be used as an indicator to proximate parameters related to human well-being. Overall, the electrification process in Indonesia has been accelerating in the past two decades. Unfortunately, monitoring the country's progress on its effort to provide wider access to electricity poses challenges due to inconsistency of data provided by each national bureau, and limited availability of information. This study attempts to provide a reliable measure by employing nighttime satellite imagery to observe and to map the progress of electrification within a duration of 20 years, from 1993 to 2013. Brightness of 67,021 settlement-size points in 1993, 2003, and 2013 was assessed using data from DMSP/OLS instruments to study the electrification progress in the three service regions (Sumatera, Java-Bali, and East Indonesia) of the country's public electricity company, PLN. Observation of all service areas shows that the increase in brightness, which correspond with higher electricity development and consumption, has positive correlation with both population density (R(2) = 0.70) and urban change (R(2) = 0.79). Moreover, urban change has a stronger correlation with brightness, which is probably due to the high energy consumption in urban area per capita. This study also found that the brightness in Java-Bali region is very dominant, while the brightness in other areas has been lagging during the period of analysis. The slow development of electricity infrastructure, particularly in major parts of East Indonesia region, affects the low economic growth in some areas and formed vicious cycle.

  16. Analysis of spatial inhomogeneities in cumulus clouds using high spatial resolution Landsat data

    NASA Technical Reports Server (NTRS)

    Parker, Lindsay; Welch, R. M.; Musil, D. J.

    1986-01-01

    Aircraft observations and high resolution Landsat MSS digital data are used to determine the sizes of spatial inhomogeneities ('holes') in cumulus clouds. The majority of holes are found near cloud edges, but the larger holes tend to be found in cloud interiors. Aircraft measurements show these cloud spatial inhomogeneities in the range of 100 to 500 m, while Landsat data show them in the range of 100 m to 3 km. The number of holes per cloud decreases exponentially with increasing hole diameter. Small clouds not only have smaller holes, but also fewer holes than large clouds. Large clouds have large holes in them, as well as large numbers of the smaller holes. The total cloud area occupied by holes increases with increasing cloud size.

  17. Clustering, randomness and regularity in cloud fields. I - Theoretical considerations. II - Cumulus cloud fields

    NASA Technical Reports Server (NTRS)

    Weger, R. C.; Lee, J.; Zhu, Tianri; Welch, R. M.

    1992-01-01

    The current controversy existing in reference to the regularity vs. clustering in cloud fields is examined by means of analysis and simulation studies based upon nearest-neighbor cumulative distribution statistics. It is shown that the Poisson representation of random point processes is superior to pseudorandom-number-generated models and that pseudorandom-number-generated models bias the observed nearest-neighbor statistics towards regularity. Interpretation of this nearest-neighbor statistics is discussed for many cases of superpositions of clustering, randomness, and regularity. A detailed analysis is carried out of cumulus cloud field spatial distributions based upon Landsat, AVHRR, and Skylab data, showing that, when both large and small clouds are included in the cloud field distributions, the cloud field always has a strong clustering signal.

  18. Analysis of spatial inhomogeneities in cumulus clouds using high spatial resolution Landsat data

    NASA Technical Reports Server (NTRS)

    Parker, Lindsay; Welch, R. M.; Musil, D. J.

    1986-01-01

    Aircraft observations and high resolution Landsat MSS digital data are used to determine the sizes of spatial inhomogeneities ('holes') in cumulus clouds. The majority of holes are found near cloud edges, but the larger holes tend to be found in cloud interiors. Aircraft measurements show these cloud spatial inhomogeneities in the range of 100 to 500 m, while Landsat data show them in the range of 100 m to 3 km. The number of holes per cloud decreases exponentially with increasing hole diameter. Small clouds not only have smaller holes, but also fewer holes than large clouds. Large clouds have large holes in them, as well as large numbers of the smaller holes. The total cloud area occupied by holes increases with increasing cloud size.

  19. Interactions between a tropical mixed boundary layer and cumulus convection in a radiative-convective model

    NASA Astrophysics Data System (ADS)

    Dean, C. L.

    1993-05-01

    A radiative-convective model, combining previously developed cumulus, stable cloud and radiation parameterizations with a boundary layer scheme, which was developed in the current study is detailed. The cloud model was modified to incorporate the effects of both small and large clouds. The boundary layer model which was adapted from a mixed layer model was only slightly modified to couple it with the more sophisticated cloud model. The model was tested for a variety of imposed divergence profiles, which simulate the regions of the tropical ocean from approximately the Intertropical Convergence Zone (ITCZ) to the subtropical high region. The sounding used to initialize the model for most of the runs is from the trade wind region of ATEX. For each experiment, the model was run with a timestep of 300 seconds for a period of 7 days.

  20. Derivation of Cumulus Cloud Dimensions and Shape from the Airborne Measurements by the Research Scanning Polarimeter

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail D.; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; Ottaviani, Matteo; Wasilewski, Andrzej P.

    2016-01-01

    The Research Scanning Polarimeter (RSP) is an airborne instrument, whose measurements have been extensively used for retrievals of microphysical properties of clouds. In this study we show that for cumulus clouds the information content of the RSP data can be extended by adding the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground. This extension is possible by virtue of the high angular resolution and high frequency of the RSP measurements, which allow for geometric constraint of the cloud's 2D cross section between a number of tangent lines of view. The retrieval method is tested on realistic 3D radiative transfer simulations and applied to actual RSP data.

  1. Derivation of Cumulus Cloud Dimensions and Shape from the Airborne Measurements by the Research Scanning Polarimeter

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail D.; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; Ottaviani, Matteo; Wasilewski, Andrzej P.

    2016-01-01

    The Research Scanning Polarimeter (RSP) is an airborne instrument, whose measurements have been extensively used for retrievals of microphysical properties of clouds. In this study we show that for cumulus clouds the information content of the RSP data can be extended by adding the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground. This extension is possible by virtue of the high angular resolution and high frequency of the RSP measurements, which allow for geometric constraint of the cloud's 2D cross section between a number of tangent lines of view. The retrieval method is tested on realistic 3D radiative transfer simulations and applied to actual RSP data.

  2. Air turbulence measurements in and below cumulus congestus over mountainous terrain

    NASA Technical Reports Server (NTRS)

    Cotton, W. R.; Hahn, D. C.; Banta, R.

    1978-01-01

    Consideration is given to the definition and application to air turbulence measurements over mountainous terrain of the ensemble averaging operator in the second-order turbulent transfer model of moist, precipitating mesoscale systems developed by Manton and Cotton (1977) as a first step in the formulation of a unified mesoscale turbulence theory. The use of running means to smooth out point-to-point data variability is proposed as a means of avoiding certain of the problems associated with ensemble averaging, and is applied to airborne velocity measurements in cumulus congestus over South Park, Colorado. It is found that, in general, vertical transport of any cloud parameter will be primarily eddy transport in the mesoscale modeling of cloud processes.

  3. Interaction of a cumulus cloud ensemble with the large-scale environment. IV - The discrete model

    NASA Technical Reports Server (NTRS)

    Lord, S. J.; Chao, W. C.; Arakawa, A.

    1982-01-01

    The Arakawa-Schubert (1974) parameterization is applied to a prognostic model of large-scale atmospheric circulations and used to analyze data in a general circulation model (GCM). The vertical structure of the large-scale model and the solution for the cloud subensemble thermodynamical properties are examined to choose cloud levels and representative regions. A mass flux distribution equation is adapted to formulate algorithms for calculating the large-scale forcing and the mass flux kernel, using either direct solution or linear programming. Finally, the feedback of the cumulus ensemble on the large-scale environment for a given subensemble mass flux is calculated. All cloud subensemble properties were determined from the conservation of mass, moist static energy, and total water.

  4. Optical properties of continental haze and cumulus and orographic clouds based on Space Shuttle polarimetric observations.

    PubMed

    Egan, W G; Israel, S; Sidran, M; Hindman, E E; Johnson, W R; Whitehead, V S

    1993-11-20

    Digitized Space Shuttle imagery in the red, green, and blue spectral regions (0.600, 0.540, and 0.435 µm, respectively) is used to characterize the mean radius and the index of refraction of droplets in cumulus and orographic clouds. The clouds are shown to consist concurrently of submicrometer and supermicrometer droplets, with the percent polarization indicative of the dominant sizes. Cloud development from haze as well as inhomogeneities in the cloud decks can be traced remotely. The absorption properties of clouds can also be determined remotely. An optical depth of continental haze in the same three spectral regions as the clouds is computed from the polarimetric and photometric contributions. Both Mie and Rayleigh scattering are included in the model.

  5. Observational evidence for aerosol invigoration in shallow cumulus downstream of Mount Kilauea

    NASA Astrophysics Data System (ADS)

    Mace, G. G.; Abernathy, A. C.

    2016-03-01

    Knowledge of how marine boundary layer (MBL) shallow cumulus clouds respond to changes in aerosol is central to understanding how MBL clouds modulate the climate system. Mount Kilauea on the island of Hawaii began erupting in 2008 injecting substantial SO2 into the marine boundary layer creating a unique natural laboratory. Examining data from approximately 600 passes of the A-Train downstream of Mount Kilauea over a 3 year period and separating data into aerosol optical depth quartiles, we find an unambiguous increase in marine boundary cloud top height and an increase in surface wind speed as aerosol increases while the radar reflectivity does not change substantially. We conclude that increased aerosols may have caused invigoration of the MBL clouds. Additionally, we find that increases in sub 1 km cloud fraction combined with increasing aerosol explain the increased visible reflectance suggesting that evidence for the so-called first aerosol indirect effect should be reexamined.

  6. Cumulus cloud field morphology and spatial patterns derived from high spatial resolution Landsat imagery

    NASA Technical Reports Server (NTRS)

    Sengupta, S. K.; Welch, R. M.; Navar, M. S.; Berendes, T. A.; Chen, D. W.

    1990-01-01

    Using high-spatial-resolution Landsat MSS imagery, the cumulus cloud morphology, cloud nearest-neighbor distributions, and cloud clumping scales were investigated. It is shown that the cloud-size distribution can be represented by a mixture of two power laws; clouds of diameters less than 1 km have power-law slope range of 1.4-2.3, while larger clouds have slopes from 2.1 to 4.75. The break in power-law slope occurs at the cloud size that makes the largest contribution to cloud cover. Results suggest that larger clouds grow at the expense of smaller clouds. It was also found that the cloud inhomogeneities have significant impact on radiative fluxes.

  7. Precipitation susceptibility in marine stratocumulus and shallow cumulus from airborne measurements

    NASA Astrophysics Data System (ADS)

    Jung, Eunsil; Albrecht, Bruce A.; Sorooshian, Armin; Zuidema, Paquita; Jonsson, Haflidi H.

    2016-09-01

    Precipitation tends to decrease as aerosol concentration increases in warm marine boundary layer clouds at fixed liquid water path (LWP). The quantitative nature of this relationship is captured using the precipitation susceptibility (So) metric. Previously published works disagree on the qualitative behavior of So in marine low clouds: So decreases monotonically with increasing LWP or cloud depth (H) in stratocumulus clouds (Sc), while it increases and then decreases in shallow cumulus clouds (Cu). This study uses airborne measurements from four field campaigns on Cu and Sc with similar instrument packages and flight maneuvers to examine if and why So behavior varies as a function of cloud type. The findings show that So increases with H and then decreases in both Sc and Cu. Possible reasons for why these results differ from those in previous studies of Sc are discussed.

  8. Clustering, randomness and regularity in cloud fields. I - Theoretical considerations. II - Cumulus cloud fields

    NASA Technical Reports Server (NTRS)

    Weger, R. C.; Lee, J.; Zhu, Tianri; Welch, R. M.

    1992-01-01

    The current controversy existing in reference to the regularity vs. clustering in cloud fields is examined by means of analysis and simulation studies based upon nearest-neighbor cumulative distribution statistics. It is shown that the Poisson representation of random point processes is superior to pseudorandom-number-generated models and that pseudorandom-number-generated models bias the observed nearest-neighbor statistics towards regularity. Interpretation of this nearest-neighbor statistics is discussed for many cases of superpositions of clustering, randomness, and regularity. A detailed analysis is carried out of cumulus cloud field spatial distributions based upon Landsat, AVHRR, and Skylab data, showing that, when both large and small clouds are included in the cloud field distributions, the cloud field always has a strong clustering signal.

  9. Influence of radiative heating and cumulus convection on development of mean monsoon circulation in July

    NASA Technical Reports Server (NTRS)

    Kuo, H. L.; Qian, Y. F.; Chen, Y. J.

    1983-01-01

    Numerical simulations of July mean monsoon circulation in the tropics are described. The model used in the simulations was based on a series of primitive equations for the combined effects of variations of solar radiation, radiative diurnal warming, and large-scale and deep cumulus condensation, and the kinematic effects of topography. The initial states of the model were derived from the observed mean distributions of pressure and humidity. Analysis of the numerical results showed that the large-scale features of the mean July monsoon circulation in the tropics are created mainly by differential diabatic heating under the influence of the specific topography. The time necessary to establish the large scale features was only about 5 days when the diurnal variation of solar radiation was taken into account. Graphic illustrations of the simulated mean July flow conditions are provided.

  10. Interactions between a tropical mixed boundary layer and cumulus convection in a radiative-convective model

    SciTech Connect

    Dean, Caryn L.

    1993-05-01

    This report details a radiative-convective model, combining previously developed cumulus, stable cloud and radiation parameterizations with a boundary layer scheme, which was developed in the current study. The cloud model was modified to incorporate the effects of both small and large clouds. The boundary layer model was adapted from a mixed layer model was only slightly modified to couple it with the more sophisticated cloud model. The model was tested for a variety of imposed divergence profiles, which simulate the regions of the tropical ocean from approximately the intertropical Convergence Zone (ITCZ) to the subtropical high region. The sounding used to initialize the model for most of the runs is from the trade wind region of ATEX. For each experiment, the model was run with a timestep of 300 seconds for a period of 7 days.

  11. Incorporation of a Cumulus Fraction Scheme in the GRAPES_Meso and Evaluation of Its Performance

    NASA Astrophysics Data System (ADS)

    Zheng, X.

    2016-12-01

    Accurate simulation of cloud cover fraction is a key and difficult issue in numerical modeling studies. Preliminary evaluations have indicated that cloud fraction is generally underestimated in GRAPES_Meso simulations, while the cloud fraction scheme (CFS) of ECMWF can provide more realistic results. Therefore, the ECMWF cumulus fraction scheme is introduced into GRAPES_Meso to replace the original CFS, and the model performance with the new CFS is evaluated based on simulated three-dimensional cloud fractions and surface temperature. Results indicate that the simulated cloud fractions increase and become more accurate with the new CFS; the simulation for vertical cloud structure has improved too; errors in surface temperature simulation have decreased. The above analysis and results suggest that the new CFS has a positive impact on cloud fraction and surface temperature simulation.

  12. Improving Forecasts of Cumulus: An Intersection of the Renewable Energy and Climate Science Communities

    NASA Astrophysics Data System (ADS)

    Berg, L. K.; Gustafson, W. I., Jr.; Kassianov, E.; Long, C. N.

    2015-12-01

    Accurate forecasts of broken cloud fields and their associated impact on the downwelling solar irradiance has remained a challenge to the renewable energy industry. Likewise, shallow cumulus play an important role in the Earth's radiation budget and hydrologic cycle and are of interest to the weather forecasting and climate science communities. The main challenge associated with predicting these clouds are their relatively small size (on the order of a kilometer or less) relative to the model grid spacing. Recently, however, there have been significant efforts put into improving forecasts of shallow clouds and the associated temporal and spatial variability of the solar irradiance that they induce. As an example of these efforts, we will describe recent modifications to the standard Kain-Fritsch parameterization as applied within the Weather Research and Forecasting (WRF) model that are designed to improve predictions of the macroscale and microscale structure of shallow cumulus. These modifications are shown to lead to a realistic increase in the simulated cloud fraction and associated decrease in the solar irradiance. We will evaluate our results using data collected at the Department of Energy's Atmospheric Radiation Measurement (ARM) Southern Great Plains site, which is located in north-central Oklahoma. Our team has analyzed over 5 years of data collected at this site to document the macroscale structure of the clouds (including cloud fraction, cloud-base and cloud-top height) as well as their impact on the downwelling shortwave and longwave irradiance. One particularly interesting impact of shallow cumuli is the enhancement of the diffuse radiation, such that during periods in which the sun is not blocked, the observed irradiance can be significantly larger than the corresponding clear sky case. To date, this feature is not accurately represented by models that apply the plane-parallel assumption applied in the standard radiation parameterizations.

  13. Observational estimates of detrainment and entrainment in non-precipitating shallow cumulus

    NASA Astrophysics Data System (ADS)

    Norgren, M. S.; Small, J. D.; Jonsson, H. H.; Chuang, P. Y.

    2016-01-01

    Vertical transport associated with cumulus clouds is important to the redistribution of gases, particles, and energy, with subsequent consequences for many aspects of the climate system. Previous studies have suggested that detrainment from clouds can be comparable to the updraft mass flux, and thus represents an important contribution to vertical transport. In this study, we describe a new method to deduce the amounts of gross detrainment and entrainment experienced by non-precipitating cumulus clouds using aircraft observations. The method utilizes equations for three conserved variables: cloud mass, total water, and moist static energy. Optimizing these three equations leads to estimates of the mass fractions of adiabatic mixed-layer air, entrained air and detrained air that the sampled cloud has experienced. The method is applied to six flights of the CIRPAS Twin Otter during the Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) which took place in the Houston, Texas region during the summer of 2006 during which 176 small, non-precipitating cumuli were sampled. Using our novel method, we find that, on average, these clouds were comprised of 30 to 70 % mixed-layer air, with entrained air comprising most of the remainder. The mass fraction of detrained air was usually very small, less than 2 %, although values larger than 10 % were found in 15 % of clouds. Entrained and detrained air mass fractions both increased with altitude, consistent with some previous observational studies. The largest detrainment events were almost all associated with air that was at their level of neutral buoyancy, which has been hypothesized in previous modeling studies. This new method could be readily used with data from other previous aircraft campaigns to expand our understanding of detrainment for a variety of cloud systems.

  14. Dynamics, thermodynamics, radiation, and cloudiness associated with cumulus-topped marine boundary layers

    SciTech Connect

    Ghate, Virendra P.; Miller, Mark

    2016-11-01

    The overall goal of this project was to improve the understanding of marine boundary clouds by using data collected at the Atmospheric Radiation Measurement (ARM) sites, so that they can be better represented in global climate models (GCMs). Marine boundary clouds are observed regularly over the tropical and subtropical oceans. They are an important element of the Earth’s climate system because they have substantial impact on the radiation budget together with the boundary layer moisture, and energy transports. These clouds also have an impact on large-scale precipitation features like the Inter Tropical Convergence Zone (ITCZ). Because these clouds occur at temporal and spatial scales much smaller than those relevant to GCMs, their effects and the associated processes need to be parameterized in GCM simulations aimed at predicting future climate and energy needs. Specifically, this project’s objectives were to (1) characterize the surface turbulent fluxes, boundary layer thermodynamics, radiation field, and cloudiness associated with cumulus-topped marine boundary layers; (2) explore the similarities and differences in cloudiness and boundary layer conditions observed in the tropical and trade-wind regions; and (3) understand similarities and differences by using a simple bulk boundary layer model. In addition to working toward achieving the project’s three objectives, we also worked on understanding the role played by different forcing mechanisms in maintaining turbulence within cloud-topped boundary layers We focused our research on stratocumulus clouds during the first phase of the project, and cumulus clouds during the rest of the project. Below is a brief description of manuscripts published in peer-reviewed journals that describe results from our analyses.

  15. Observations of the variability of shallow trade wind cumulus cloudiness and mass flux

    NASA Astrophysics Data System (ADS)

    Lamer, K.; Kollias, P.; Nuijens, L.

    2015-06-01

    Two years of ground-based remote sensing observations are used to study the vertical structure of marine cumulus near the island of Barbados, including their cloud fraction and mass flux profile. Daily radar derived cloud fraction profiles peak at different height levels depending on the depth of the cumuli and thus the extent to which they precipitate. Nonprecipitating cumuli have a peak cloud fraction of about 5% near mean cloud base (700 m), whereas precipitating cumuli tend to have a peak of only 2% near cloud base. Nineteen percent of the precipitating cumuli are accompanied by large cloud fractions near the detrainment level of cumulus tops (~1700 m). Day-to-day variations in cloud fraction near cloud base are modest (~3%). Nonprecipitating cumuli have their largest reflectivities near cloud top and an ascending core surrounded by a subsiding shell. Precipitating cumuli with enhanced elevated cloudiness (stratiform outflow) are deeper and contain larger vertical gradients in reflectivity and Doppler velocity than precipitating cumuli without such outflow. Bulk (3 h) statistics reveal that nonprecipitating shallow cumuli are active and organized. They contain on average 79% in-cloud updrafts with 86% of them being organized in large coherent structures contributing to a maximum updraft mass flux of 8-36 gm-2 s-1 just above cloud base. Alternatively, downdrafts contribute insignificantly to the mass flux and show little vertical and temporal variability (0-7 gm-2 s-1). Complementary Raman lidar information suggests that updraft mass flux profile slope is inversely related to environmental relative humidity.

  16. Safety of brilliant cresyl blue staining protocols on human granulosa and cumulus cells.

    PubMed

    Alcoba, Diego Duarte; Conzatti, Maiara; Ferreira, Gustavo Dias; Pimentel, Anita Mylius; Kussler, Ana Paula; Capp, Edison; von Eye Corleta, Helena; Brum, Ilma Simoni

    2016-02-01

    The selection of human immature oocytes destined for in vitro maturation (IVM) is performed according to their cumulus-oocyte complex (COC) morphology. In animal models, oocyte pre-selection with brilliant cresyl blue (BCB) staining improves fertilization and blastocyst rates and even increases the number of calves born. As the granulosa cells and cumulus cells (GCs and CCs) have a close relationship with the oocyte and are available in in vitro fertilization (IVF) programs, applying BCB staining to these cells may help to elucidate whether BCB shows toxicity to human oocytes and to determine the safest protocol for this dye. GCs and CCs were isolated from 24 patients who underwent controlled ovarian stimulation. After 48 h, cells were exposed to: Dulbecco's Modified Eagle Medium (DMEM) with or without phenol red, DPBS and mDPBS for 60 min; 13, 20 and 26 μM BCB for 60 min; and 60, 90 or 120 min to 13 μM BCB. Cellular viability was tested using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) and trypan blue assays. The 20 and 26 μM BCB exposures resulted in lower cell viability, similar to when cells were exposed to BCB for 90 or 120 min. GCs and CCs viabilities were equal among control group and 13 μM BCB group after 60 min. BCB staining was not toxic to GCs and CCs when the regime of 13 μM BCB for 60 min was used. Due to the close molecular/biochemical relationship between these cells and the gamete, we propose that it is unlikely that the use of BCB could interfere with the viability/health of human oocytes.

  17. Improving ENSO periodicity simulation by adjusting cumulus entrainment in BCC_CSMs

    NASA Astrophysics Data System (ADS)

    Lu, Bo; Ren, Hong-Li

    2016-12-01

    The simulation of El Niño-Southern Oscillation (ENSO) phenomenon is a challenging issue for coupled climate models. This study focuses on the ENSO periodicity simulated by Beijing Climate Center Climate System Models (BCC_CSM1.1 and BCC_CSM1.1m) which can reproduce reasonably well ENSO amplitude as observations. However, the major period of ENSO simulated by the BCC_CSMs is around 2.4 years, which is much shorter than that in observations. Compared with other 24 coupled models in Coupled Model Intercomparison Project Phase 5 (CMIP5), BCC_CSMs produce a very unrealistic ENSO peak period. Such a bias in simulating periodicity is suggested as a consequence of the severely underestimated air-sea coupling intensity in BCC_CSMs. To test this hypothesis, a quantitative method is developed to diagnose the linear ENSO frequency. As an effort to improve the ENSO simulation in BCC_CSMs, three experiments are performed with varying entrainment rates in the cumulus convection parameterization scheme of BCC_CSM1.1m. A more realistic ENSO period of about 3.3 years can be generated by the model with an inflated entrainment rate. When the cumulus entrainment is increased by 10%, the ENSO-related convective precipitation will enhance in the equatorial central to eastern Pacific. This anomalous convective heating induces an intensified surface westerly wind stress to the west of the anomalous convection center and as a result, the air-sea coupling intensity becomes larger, which contributes to a longer period of ENSO based on previous theories. In addition, the pronounced eastward extension of ENSO-related surface wind stress could also be the secondary factor to generate a lower frequency of ENSO in BCC_CSMs. Our study proposes a method to reduce the biases in ENSO periodicity simulation and puts more insights into the importance of adjusting atmospheric convection to reproduce ENSO properties in coupled model.

  18. Investigation of Aerosol Indirect Effects using a Cumulus Microphysics Parameterization in a Regional Climate Model

    SciTech Connect

    Lim, Kyo-Sun; Fan, Jiwen; Leung, Lai-Yung R.; Ma, Po-Lun; Singh, Balwinder; Zhao, Chun; Zhang, Yang; Zhang, Guang; Song, Xiaoliang

    2014-01-29

    A new Zhang and McFarlane (ZM) cumulus scheme includes a two-moment cloud microphysics parameterization for convective clouds. This allows aerosol effects to be investigated more comprehensively by linking aerosols with microphysical processes in both stratiform clouds that are explicitly resolved and convective clouds that are parameterized in climate models. This new scheme is implemented in the Weather Research and Forecasting (WRF) model, which is coupled with the physics and aerosol packages from the Community Atmospheric Model version 5 (CAM5). A test case of July 2008 during the East Asian summer monsoon is selected to evaluate the performance of the new ZM scheme and to investigate aerosol effects on monsoon precipitation. The precipitation and radiative fluxes simulated by the new ZM scheme show a better agreement with observations compared to simulations with the original ZM scheme that does not include convective cloud microphysics and aerosol convective cloud interactions. Detailed analysis suggests that an increase in detrained cloud water and ice mass by the new ZM scheme is responsible for this improvement. To investigate precipitation response to increased anthropogenic aerosols, a sensitivity experiment is performed that mimics a clean environment by reducing the primary aerosols and anthropogenic emissions to 30% of that used in the control simulation of a polluted environment. The simulated surface precipitation is reduced by 9.8% from clean to polluted environment and the reduction is less significant when microphysics processes are excluded from the cumulus clouds. Ensemble experiments with ten members under each condition (i.e., clean and polluted) indicate similar response of the monsoon precipitation to increasing aerosols.

  19. Measurements of cloud condensation nuclei spectra within maritime cumulus cloud droplets: Implications for mixing processes

    NASA Technical Reports Server (NTRS)

    Twohy, Cynthia H.; Hudson, James G.

    1995-01-01

    In a cloud formed during adiabatic expansion, the droplet size distribution will be systematically related to the critical supersaturation of the cloud condensation nuclei (CNN), but this relationship can be complicated in entraining clouds. Useful information about cloud processes, such as mixing, can be obtained from direct measurements of the CNN involved in droplet nucleation. This was accomplished by interfacing two instruments for a series of flights in maritime cumulus clouds. One instrument, the counterflow virtual impactor, collected cloud droplets, and the nonvolatile residual nuclei of the droplets was then passed to a CCN spectrometer, which measured the critical supersaturation (S(sub c)) spectrum of the droplet nuclei. The measured S(sub c) spectra of the droplet nuclei were compared with the S(sub c) spectra of ambient aerosol particles in order to identify which CCN were actually incorporated into droplets and to determine when mixing processes were active at different cloud levels. The droplet nuclei nearly always exhibited lower median S(sub c)'s than the ambient aerosol, as expected since droplets nucleate perferentially on particles with lower critical supersaturations. Critical supersaturation spectra from nuclei of droplets near cloud base were similar to those predicted for cloud regions formed adiabatically, but spectra of droplet nuclei from middle cloud levels showed some evidence that mixing had occurred. Near cloud top, the greatest variation in the spectra of the droplet nuclei was observed, and nuclei with high S(sub c)'s were sometimes present even within relatively large droplets. This suggests that the extent of mixing increases with height in cumulus clouds and that inhomogeneous mixing may be important near cloud top. These promising initial results suggest improvements to the experimental technique that will permit more quantitative results in future experiments.

  20. Fatty Acid Synthesis and Oxidation in Cumulus Cells Support Oocyte Maturation in Bovine

    PubMed Central

    Sanchez-Lazo, Laura; Brisard, Daphné; Elis, Sébastien; Maillard, Virginie; Uzbekov, Rustem; Labas, Valérie; Desmarchais, Alice; Papillier, Pascal; Monget, Philippe

    2014-01-01

    Oocyte meiotic maturation requires energy from various substrates including glucose, amino acids, and lipids. Mitochondrial fatty acid (FA) β-oxidation (FAO) in the oocyte is required for meiotic maturation, which is accompanied by differential expression of numerous genes involved in FAs metabolism in surrounding cumulus cells (CCs) in vivo. The objective was to elucidate components involved in FAs metabolism in CCs during oocyte maturation. Twenty-seven genes related to lipogenesis, lipolysis, FA transport, and FAO were chosen from comparative transcriptome analysis of bovine CCs before and after maturation in vivo. Using real-time PCR, 22 were significantly upregulated at different times of in vitro maturation (IVM) in relation to oocyte meiosis progression from germinal vesicle breakdown to metaphase-II. Proteins FA synthase, acetyl-coenzyme-A carboxylase, carnitine palmitoyltransferase, perilipin 2, and FA binding protein 3 were detected by Western blot and immunolocalized to CCs and oocyte cytoplasm, with FA binding protein 3 concentrated around oocyte chromatin. By mass spectrometry, CCs lipid profiling was shown to be different before and after IVM. FAO inhibitors etomoxir and mildronate dose-dependently decreased the oocyte maturation rate in vitro. In terms of viability, cumulus enclosed oocytes were more sensitive to etomoxir than denuded oocytes. In CCs, etomoxir (150μM) led to downregulation of lipogenesis genes and upregulated lipolysis and FAO genes. Moreover, the number of lipid droplets decreased, whereas several lipid species were more abundant compared with nontreated CCs after IVM. In conclusion, FAs metabolism in CCs is important to maintain metabolic homeostasis and may influence meiosis progression and survival of enclosed oocytes. PMID:25058602

  1. Measurements of cloud condensation nuclei spectra within maritime cumulus cloud droplets: Implications for mixing processes

    NASA Technical Reports Server (NTRS)

    Twohy, Cynthia H.; Hudson, James G.

    1995-01-01

    In a cloud formed during adiabatic expansion, the droplet size distribution will be systematically related to the critical supersaturation of the cloud condensation nuclei (CNN), but this relationship can be complicated in entraining clouds. Useful information about cloud processes, such as mixing, can be obtained from direct measurements of the CNN involved in droplet nucleation. This was accomplished by interfacing two instruments for a series of flights in maritime cumulus clouds. One instrument, the counterflow virtual impactor, collected cloud droplets, and the nonvolatile residual nuclei of the droplets was then passed to a CCN spectrometer, which measured the critical supersaturation (S(sub c)) spectrum of the droplet nuclei. The measured S(sub c) spectra of the droplet nuclei were compared with the S(sub c) spectra of ambient aerosol particles in order to identify which CCN were actually incorporated into droplets and to determine when mixing processes were active at different cloud levels. The droplet nuclei nearly always exhibited lower median S(sub c)'s than the ambient aerosol, as expected since droplets nucleate perferentially on particles with lower critical supersaturations. Critical supersaturation spectra from nuclei of droplets near cloud base were similar to those predicted for cloud regions formed adiabatically, but spectra of droplet nuclei from middle cloud levels showed some evidence that mixing had occurred. Near cloud top, the greatest variation in the spectra of the droplet nuclei was observed, and nuclei with high S(sub c)'s were sometimes present even within relatively large droplets. This suggests that the extent of mixing increases with height in cumulus clouds and that inhomogeneous mixing may be important near cloud top. These promising initial results suggest improvements to the experimental technique that will permit more quantitative results in future experiments.

  2. Stratocumulus-to-Cumulus transition: Case Studies from North Pacific and North Atlantic

    NASA Astrophysics Data System (ADS)

    Ghate, Virendra; Mechem, David; Cadeddu, Maria; Eloranta, Edwin; Jensen, Michael; Stevens, Bjorn

    2017-04-01

    Marine boundary layer clouds cover vast areas of the eastern subtropical oceans and have a significant impact on the Earth's radiation budget. Marine stratocumulus (Sc) clouds form in regions with cold sea surface temperatures (SSTs) and strong boundary layer inversion that is maintained by a largescale subsidence. As these clouds are advected towards the trade-wind regions that have warmer SSTs and weak inversion, they decouple from the surface and transition to broken cumulus (Cu) clouds. This transition from stratocumulus to cumulus cloud (Sc-to-Cu) regime is thought to occur due to a complex interplay of processes modulated by surface fluxes, boundary layer radiative cooling, inversion strength, and precipitation. Previous modeling studies have shown this transition to occur over a span of three days with the nighttime radiative cooling on the first two days able to recouple (well-mix) the boundary layer after daytime decoupling, with the nighttime radiative cooling on the third day being too weak to be able to recouple the boundary layer. Additionally, there is considerable debate over the relative influence of different mechanisms (precipitation vs entrainment) in causing the decoupling. In this study, we have used the data collected during the MAGIC field campaign from a five-day period to study the boundary layer cloud transitions. The data collected by in situ and remote sensing instruments were used to retrieve the cloud macro- and micro-physical properties, which were then used to calculate profiles of radiative fluxes. The day-to-day changes in cloud, precipitation, radiation and boundary layer properties for the transition will be presented. We will also make an attempt to identify few cases that showcased transition of air-mass from the Atmospheric Radiation Measurement (ARM)'s Eastern North Atlantic site to the Barbados Cloud Observatory (BCO). This will enable us to study the boundary layer cloud transitions in the North Atlantic by contrasting the

  3. Key factors for the implementation of successful, stand-alone village electrification schemes in Peru

    NASA Astrophysics Data System (ADS)

    Sanchez-Campos, Teodoro

    The hypothesis of this work is that there are social, financial, technical, managerial institutional and political key factors that may either support or prevent the success of small stand alone energy systems in rural areas. This research work aims at contributing to the identification of such factors and study their relevance to the performance and sustainability of stand alone energy systems in rural areas; to meet its purpose, a wide range of literature was reviewed including rural electrification programmes and projects, research and development projects on access to electricity in rural areas, impact studies and others, and a field research survey was done the Andes and Upper Jungle regions in Peru. Nineteen possible critical factors were identified, thirteen with relevance at the local context (the community or village), and six with relevance at the national (or wider) context. From literature review it was found that the possible local critical factors were relevant only to four categories of factors instead of the six considered initially (i.e. social, financial, technological and managerial): the other two categories, political and institutional were found to be more relevant to the national context, therefore those were included in the group of possible critical factors of wider context. A series of questionnaires were designed to collect field data information, which was later used to analyse and establish the relation of each identified factor with the success of the systems studied. The survey research was implemented in 14 villages, 7 with small diesel sets and 7 with small hydropower schemes, all spread in the Andes and Upper Jungle of Peru, which were carefully selected to be representative of regions with isolated stand alone systems and with different socioeconomic background. Out of the 13 possible critical factors of local context, it was found that only 3 are really critical, the others are important but not critical; one of them (technical

  4. Alternate electrification and non-potable water: A health concern for Jamaicans

    PubMed Central

    Crawford, Tazhmoye V.

    2009-01-01

    Background: Research has shown that the absence of electricity and potable water usually result in negative effects on one's health and is more likely to affect women than men. Aim: To determine the extent to which alternate electrification and limited potable water, impacts on health. Materials and Method: This study is informed by primary and secondary data, representing a sample size of 150 respondents (75 male and 75 female), who were interviewed via a 24-item structured interview schedule during the period 2006-2007, throughout the 14 parishes of Jamaica. In an effort to determine the number of persons to be interviewed, each parish population was divided by the island's population (2,599,334) and then multiplied by 150. Data was analyzed using the statistical package for social scientists 15. Results: The respondents of this study who use kerosene lamp as an alternate means to electricity use firewood for cooking (12% male and 15% female). This sometimes result in obstructive pulmonary disease (female 43%; male 21%). The absence of electricity also results in the consumption of improperly stored meat, thus medical implications: paroxysmal abdominal pain (colic), and diarrhea (male 91%; female, 95%). The transporting of firewood, pans of water and laundry via head-loading, sometimes result in back/spinal injury (male, 75%; female, 48%). Conclusion: Alternate access to electricity and potable water result in the use of kerosene lamp, firewood and the consumption of non-potable water (often transported on one's head) - causing medical implications such as back/spinal injury, obstructive pulmonary disease, paroxysmal abdominal pain and gastroenteritis. PMID:22666721

  5. Detection of Shallow Marine Cumulus Convection with airborne and spaceborne Lidar-Systems over the tropical North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Gutleben, Manuel; Groß, Silke; Wirth, Martin

    2017-04-01

    Recent modeling and theoretical studies have shown that the vertical and horizontal distribution of cloudiness in the trades has a large impact on the results of cloud feedback calculations. In particular, feedbacks from marine cumulus convection in the boundary layer with maximum cloud top heights of 4 km introduce large uncertainties in climate sensitivity. Characterizing shallow marine cumulus clouds using passive satellite measurements is difficult. The small size of these clouds and the low horizontal resolution of passive satellite sensors as well as the influence of solar background noise on measurements lead to inevitable errors. Airborne lidar instruments allow measurements with high temporal and spatial resolution and are therefore suitable for the investigation of small scale shallow marine cumulus clouds. During the field campaigns NARVAL-I and -II (Next-generation Aircraft Remote-sensing for VALidation studies) in December 2013 and August 2016 over the North Atlantic Ocean measurements with the DLR high spectral resolution and differential absorption lidar system WALES onboard the German research aircraft HALO were performed. Those measurements provide the opportunity to study the horizontal and vertical distribution of shallow marine cumulus convection. Since measurements during NARVAL-I in December 2013 were conducted during the dry season and measurements during NARVAL-II in August 2016 were conducted during the wet season, they can furthermore be used to study seasonal differences in cloud size and cloud top height distributions. During both campaigns sets of A-Train underpasses were flown, that allow to examine the benefit of spaceborne lidar measurements to study shallow marine cumulus convection. In our presentation we will give an overview of the measurements and we will show first results of derived shallow marine cumulus cloud statistics over the subtropical North Atlantic Ocean. In particular, we present statistical quantities such as cloud

  6. The effect of cumulus friction on the simulation of the January Hadley Circulation by the GLAS model of the general circulation

    NASA Technical Reports Server (NTRS)

    Helfand, H. M.

    1979-01-01

    A method of parameterizing the vertical mixing of horizontal momentum by cumulus convection was added to the GLAS model of the general circulation of the tropics. Addition of the cumulus friction term strengthened the winter Hadley circulation and smoothed the mean meridional wind field, with a slight increase in the eddy kinetic energy. The results showed that the intensity of the meridional circulation is regulated by the atmosphere's angular momentum budget, changes in the zonally-averaged Coriolis force correlate with the new cumulus friction term, and the intensification of Hadley circulation is a response of the mean meridional flow field to the downward cumulus field of relative angular momentum in the winter hemisphere.

  7. Role of a cumulus parameterization scheme in simulating atmospheric circulation and rainfall in the nine-layer Goddard Laboratory for Atmospheres General Circulation Model

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Chao, Winston C.; Walker, G. K.

    1992-01-01

    The influence of a cumulus convection scheme on the simulated atmospheric circulation and hydrologic cycle is investigated by means of a coarse version of the GCM. Two sets of integrations, each containing an ensemble of three summer simulations, were produced. The ensemble sets of control and experiment simulations are compared and differentially analyzed to determine the influence of a cumulus convection scheme on the simulated circulation and hydrologic cycle. The results show that cumulus parameterization has a very significant influence on the simulation circulation and precipitation. The upper-level condensation heating over the ITCZ is much smaller for the experiment simulations as compared to the control simulations; correspondingly, the Hadley and Walker cells for the control simulations are also weaker and are accompanied by a weaker Ferrel cell in the Southern Hemisphere. Overall, the difference fields show that experiment simulations (without cumulus convection) produce a cooler and less energetic atmosphere.

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