Earth Observations taken by Expedition 30 crewmember

NASA Image and Video Library

2012-02-05

ISS030-E-090012 (5 Feb. 2012) --- The Parana River floodplain along the Mato Grosso–Sao Paulo border, Brazil is featured in this image photographed by an Expedition 30 crew member on the International Space Station. The Parana River appears as a wide, blue strip across this photograph, with muddy brown water of the smaller Verde River entering from the northwest (top left). An extensive wetland (dark green) occupies most of the left half of the image, where the floodplain of the river reaches a width of 11 kilometers. The thin line of a road crossing the floodplain also gives a sense of scale. Above the Parana–Verde confluence (center) the floodplain is much narrower. The floodplain is generated by sediments delivered by both rivers. Evidence for this is that the entire surface of the floodplain is crisscrossed by the wider traces of former Parana R. channels as well as numerous narrower traces of the Verde R. The floodplains along both rivers are bordered by numerous rectangular agricultural fields. Dominant crops along this part of the Parana River are coffee, corn and cotton. Turbid water, such as that in the Verde River, is common in most rivers that drain plowed agricultural land as some topsoil is washed into local rivers after rains. A long tendril of brown water extends from the Verde R. into the main channel of the Parana River where it hugs the west bank, remaining unmixed for many kilometers. This effectively shows the direction of river flow from orbit (right to left for the Parana, upper left to center for the Verde).

Geologic Map of MTM -20012 and -25012 Quadrangles, Margaritifer Terra Region of Mars

USGS Publications Warehouse

Grant, J. A.; Wilson, S.A.; Fortezzo, C.M.; Clark, D.A.

2009-01-01

Mars Transverse Mercator (MTM) -20012 and -25012 quadrangles (lat 17.5 deg - 27.5 deg S., long 345 deg - 350 deg E.) cover a portion of Margaritifer Terra near the east end of Valles Marineris. The map area consists of a diverse assemblage of geologic surfaces including isolated knobs of rugged mountainous material, heavily cratered and dissected ancient highland material, a variety of plains materials, chaotic terrain materials, and one of the highest densities of preserved valleys and their associated deposits on the planet (Saunders, 1979; Baker, 1982; Phillips and others, 2000, 2001). The map area is centered on a degraded, partially filled, ~200-km-diameter impact structure (lat 22 deg S., long 347.5 deg E.), informally referred to as Parana basin, located between Parana Valles to the east and Loire Valles to the west. Parana Valles is a network of multidigitate, mostly east-west-oriented valleys that flowed west and discharged into Parana basin (Grant, 1987, 2000; Grant and Parker, 2002). Loire Valles, broadly comparable in length to the Grand Canyon on Earth, has a deeply incised channel within the map area that originates at the west-northwest edge of Erythraeum Chaos within Parana basin (Grant, 1987, 2000; Grant and Parker, 2002; Strom and others, 2000). Parana and Loire Valles, combined with Samara Valles to the west, form one of the most laterally extensive, well-integrated valley networks on Mars (Grant, 2000) and record a long history of modification by fluvial processes. The origin and morphology of the valley networks, therefore, provide insight into past environmental conditions, whereas their relation with other landforms helps constrain the timing and role of fluvial processes in the evolution and modification of the Margaritifer Terra region.

Effect of the time interval from harvesting to the pre-drying step on natural fumonisin contamination in freshly harvested corn from the State of Parana, Brazil.

PubMed

Da Silva, M; Garcia, G T; Vizoni, E; Kawamura, O; Hirooka, E Y; Ono, E Y S

2008-05-01

Natural mycoflora and fumonisins were analysed in 490 samples of freshly harvested corn (Zea mays L.) (2003 and 2004 crops) collected at three points in the producing chain from the Northern region of Parana State, Brazil, and correlated to the time interval between the harvesting and the pre-drying step. The two crops showed a similar profile concerning the fungal frequency, and Fusarium sp. was the prevalent genera (100%) for the sampling sites from both crops. Fumonisins were detected in all samples from the three points of the producing chain (2003 and 2004 crops). The levels ranged from 0.11 to 15.32 microg g(-1)in field samples, from 0.16 to 15.90 microg g(-1)in reception samples, and from 0.02 to 18.78 microg g(-1)in pre-drying samples (2003 crop). Samples from the 2004 crop showed lower contamination and fumonisin levels ranged from 0.07 to 4.78 microg g(-1)in field samples, from 0.03 to 4.09 microg g(-1)in reception samples, and from 0.11 to 11.21 microg g(-1)in pre-drying samples. The mean fumonisin level increased gradually from < or = 5.0 to 19.0 microg g(-1)as the time interval between the harvesting and the pre-drying step increased from 3.22 to 8.89 h (2003 crop). The same profile was observed for samples from the 2004 crop. Fumonisin levels and the time interval (rho = 0.96) showed positive correlation (p < or = 0.05), indicating that delay in the drying process can increase fumonisin levels.

Provenance and paleogeography of the Devonian Durazno Group, southern Parana Basin in Uruguay

NASA Astrophysics Data System (ADS)

Uriz, N. J.; Cingolani, C. A.; Basei, M. A. S.; Blanco, G.; Abre, P.; Portillo, N. S.; Siccardi, A.

2016-03-01

A succession of Devonian cover rocks occurs in outcrop and in the subsurface of central-northern Uruguay where they were deposited in an intracratonic basin. This Durazno Group comprises three distinct stratigraphic units, namely the Cerrezuelo, Cordobés and La Paloma formations. The Durazno Group does not exceed 300 m of average thickness and preserves a transgressive-regressive cycle within a shallow-marine siliciclastic shelf platform, and is characterized by an assemblage of invertebrate fossils of Malvinokaffric affinity especially within the Lower Devonian Cordobés shales. The sedimentary provenance of the Durazno Group was determined using petrography, geochemistry, and morphological studies of detrital zircons as well as their U-Pb ages. Sandstone petrography of Cerrezuelo and La Paloma sequences shows that they have a dominantly quartz-feldspathic composition with a minor contribution of other minerals. Whole-rock geochemical data indicate that alteration was strong in each of the three formations studied; chondritic-normalized REE patterns essentially parallel to PAAS, the presence of a negative Eu-anomaly, and Th/Sc and La/Hf ratios point to an average source composition similar to UCC or slightly more felsic. Within the Cerrezuelo Formation, recycling of older volcano-metasedimentary sources is interpreted from Zr/Sc ratios and high Hf, Zr, and REE concentrations. U-Pb detrital zircon age populations of the Cerrezuelo and La Paloma formations indicate that the principal source terranes are of Neoproterozoic age, but include also minor populations derived from Mesoproterozoic and Archean-Paleoproterozoic rocks. A provenance from the Cuchilla Dionisio-Dom Feliciano, Nico Pérez and Piedra Alta terranes of Uruguay and southern Brazil is likely. This study establishes an intracratonic extensional tectonic setting during Durazno time. Considering provenance age sources, regional paleocurrent distributions and the established orogenic history recorded in SW

Latin America Report, No. 2756

DTIC Science & Technology

1983-10-25

144; BRAZIL CHILE Bigger Harvests Expected in Parana, Rio Grande do Sul (0 ESTADO DE SAO PAULO, various dates) 14 Parana Production Rio...to equipourNavy adequately." 6362 CSOj 3342/6 COUNTRY SECTION CHILE CABINET SHAKEUP, POLITICAL SITUATION ANALYZED Jarpa’s Mission Santiago...ERCILLA in Spanish 17 Aug 83 pp 8-9 /Xrticle by Carmen Gardewi£7 /Text/ In only 1 week, Chile has become a different country. The rapidity with which

Estimation of potential biomass resource and biogas production from aquatic plants in Argentina

NASA Astrophysics Data System (ADS)

Fitzsimons, R. E.; Laurino, C. N.; Vallejos, R. H.

1982-08-01

The use of aquatic plants in artificial lakes as a biomass source for biogas and fertilizer production through anaerobic fermentation is evaluated, and the magnitude of this resource and the potential production of biogas and fertilizer are estimated. The specific case considered is the artificial lake that will be created by the construction of Parana Medio Hydroelectric Project on the middle Parana River in Argentina. The growth of the main aquatic plant, water hyacinth, on the middle Parana River has been measured, and its conversion to methane by anaerobic fermentation is determined. It is estimated that gross methane production may be between 1.0-4.1 x 10 to the 9th cu cm/year. The fermentation residue can be used as a soil conditioner, and it is estimated production of the residue may represent between 54,900-221,400 tons of nitrogen/year, a value which is 2-8 times the present nitrogen fertilizer demand in Argentina.

Argentina from MODIS

NASA Technical Reports Server (NTRS)

2002-01-01

This Moderate-resolution Imaging Spectroradiometer (MODIS) image over Argentina was acquired on April 24, 2000, and was produced using a combination of the sensor's 250-m and 500-m resolution 'true color' bands. This image was presented on June 13, 2000 as a GIFt to Argentinian President Fernando de la Rua by NASA Administrator Dan Goldin. Note the Parana River which runs due south from the top of the image before turning east to empty into the Atlantic Ocean. Note the yellowish sediment from the Parana River mixing with the redish sediment from the Uruguay River as it empties into the Rio de la Plata. The water level of the Parana seems high, which could explain the high sediment discharge. A variety of land surface features are visible in this image. To the north, the greenish pixels show forest regions, as well as characteristic clusters of rectangular patterns of agricultural fields. In the lower left of the image, the lighter green pixels show arable regions where there is grazing and farming. (Image courtesy Jacques Descloitres, MODIS Land Group, NASA GSFC)

Simulation of the hydrologic effects of afforestation in the tacuarembo river basin, Uruguay

Treesearch

N.O. von Stackelberg; G.M. Chescheir; R.W. Skaggs; D.M. Amatya

2007-01-01

The Soil and Water Assessment Tool (SWAT) was used to simulate the hydrology of two small paired catchments in northern Uruguay. The control and treatment catchments (69 and 108 ha, respectively) were monitored for a three-year pretreatment period during which the land use was grassland with livestock grazing. Subsequently, the treatment catchment was planted (57%...

Argentine Flooding Observed by NASA Satellite

NASA Image and Video Library

2016-01-07

Since August 2015, heavy rains have caused rivers to overflow and forced tens of thousands from their homes in Paraguay, Argentina and Brazil. Rosario, Argentina is located 186 miles (300 kilometers) northwest of Buenos Aires, on the western shore of the Parana River. The entire Parana River floodplain for hundreds of kilometers is still under water or wet, as seen in this image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft, acquired Jan. 6, 2016. The image covers an area of 30.8 by 33.9 miles (49.5 by 54.6 kilometers), and is located at 33 degrees south, 61 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA20295

Earth Observations taken by the Expedition 10 crew

NASA Image and Video Library

2004-10-25

ISS010-E-05070 (25 October 2004) --- Corrientes, Argentina, and the Parana River are featured in this image photographed by an Expedition 10 crewmember on the International Space Station (ISS). Corrientes, Argentina sits on the east bank of the Parana River, South America’s third largest river (after the Negro and Amazon Rivers). From its headwaters in southeastern Brazil, the river flows southwestward around southern Paraguay, and then into Argentina. Corrientes is located just inside Argentina, across the river from the southwestern tip of Paraguay. The bridge over the Parana, built in the 1970s, connects Corrientes to its sister city, Resistencia, (beyond the left edge of image) on the western bank of the river. Sun glint on the river gives it a silvery glow and emphasizes channel islands in the river, side channels, and meander scars on the floodplain opposite the city, and even reveals the pattern of disturbed flow downstream of the bridge pylons. The old part of the city appears as a zone of smaller, more densely clustered city blocks along the river to the north of a major highway, which runs through Corrientes from the General Belgrano Bridge to the northeast (upper right of image). Larger blocks of the younger cityscape, with more green space, surround these core neighborhoods.

Cocaine smuggling from Bolivia to Atlantic ports may exploit commercial trade on Mercosur Hidrovia, lacking a waterways management strategy

DOT National Transportation Integrated Search

1997-10-01

Bolivian cocaine production has been increasing and Argentine traffickers are playing a greater role in direct exportation of Bolivian cocaine to the United States and Europe. Development of the Paraguay-Parana river system (Hidrovia) into an efficie...

Nighttime IR Channels

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This night time IR image shows Parana Vallis. Parana Vallis is one of many channels located in the Martian highlands SE of Eos Chasma (the eastern end of Valles Marineris). Parana Vallis is likely to have been formed by fluvial activity.

NOTE: in nighttime images North is to the bottom of the image.

Image information: IR instrument. Latitude -24.6, Longitude 349.7 East (10.3 West). 100 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Pyruvate formate-lyase interacts directly with the formate channel FocA to regulate formate translocation.

PubMed

Doberenz, Claudia; Zorn, Michael; Falke, Dörte; Nannemann, David; Hunger, Doreen; Beyer, Lydia; Ihling, Christian H; Meiler, Jens; Sinz, Andrea; Sawers, R Gary

2014-07-29

The FNT (formate-nitrite transporters) form a superfamily of pentameric membrane channels that translocate monovalent anions across biological membranes. FocA (formate channel A) translocates formate bidirectionally but the mechanism underlying how translocation of formate is controlled and what governs substrate specificity remains unclear. Here we demonstrate that the normally soluble dimeric enzyme pyruvate formate-lyase (PflB), which is responsible for intracellular formate generation in enterobacteria and other microbes, interacts specifically with FocA. Association of PflB with the cytoplasmic membrane was shown to be FocA dependent and purified, Strep-tagged FocA specifically retrieved PflB from Escherichia coli crude extracts. Using a bacterial two-hybrid system, it could be shown that the N-terminus of FocA and the central domain of PflB were involved in the interaction. This finding was confirmed by chemical cross-linking experiments. Using constraints imposed by the amino acid residues identified in the cross-linking study, we provide for the first time a model for the FocA-PflB complex. The model suggests that the N-terminus of FocA is important for interaction with PflB. An in vivo assay developed to monitor changes in formate levels in the cytoplasm revealed the importance of the interaction with PflB for optimal translocation of formate by FocA. This system represents a paradigm for the control of activity of FNT channel proteins. Copyright © 2014 Elsevier Ltd. All rights reserved.

Format requirements of thermal neutron scattering data in a nuclear data format to succeed the ENDF format

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

Brown, D.

2014-03-31

In November 2012, the Working Party on Evaluation Cooperation Subgroup 38 (WPEC-SG38) began with the task of developing a nuclear data format and supporting infrastructure to replace the now nearly 50 year old ENDF format. The first step in this process is to develop requirements for the new format and infrastructure. In this talk, I will review the status of ENDF's Thermal Scattering Law (TSL) formats as well as support for this data in the GND format (from which the new format is expected to evolve). Finally, I hope to begin a dialog with members of the thermal neutron scatteringmore » community so that their data needs can be accurately and easily accommodated by the new format and tools, as captured by the requirements document. During this discussion, we must keep in mind that the new tools and format must; Support what is in existing data files; Support new things we want to put in data files; and Be flexible enough for us to adapt it to future unanticipated challenges.« less

Induced Star Formation

NASA Astrophysics Data System (ADS)

Kennicutt, Robert C., Jr.

Overview: Induced Star Formation and Interactions Introduction Historical Background: First Hints Systematic Studies: Starbursts Interactions and Nuclear activity IRAS and Ultralumious starburst Galaxies The 1990's: HST, Supercomputers, and the Distant Universe Key Questions and Issues Organization of Lectures Star Formation Properties of Normal Galaxies Observational Techniques Results: Star Formation in Normal Galaxies Interpretation: Star Formation Histories Global Star Formation in interacting Galaxies A Gallery of Interactions and Mergers Star Formation Statistics: Guilt By Association Tests SFRs in Interacting vs Noninteracting Galaxies Kinematic Properties and Regulation of SFRs Induced Nuclear Activity and Star Formation Background: Nuclear Spectra and Classification Nuclear Star Formation and Starbursts Nuclear Star Formation and Interactions Induced AGN Activity: Statistics of Seyfert Galaxies Environments of Quasars Kinematic Clues to the Triggering of AGNs Infrared Luminous Galaxies and Starbursts Background: IR Luminous Galaxies and IRAS Infrared Luminosity Function and Spectra Infrared Structure and Morphology Interstellar Gas X-Ray Emission and Superwinds Optical, UV, and Near-Infrared Spectra Radio Continuum Emission Evidence for Interactions and Mergers The Power Source: Starbursts or Dusty AGNs? Spectral Diagnostics of Starbursts Evolutionary Synthesis Models Applications: Integrated Colors of Interacting Galaxies Applications: Hα Emission, Colors, and SFRs Applications: Spectral Modelling of Evolved Starbursts Infrared Starbursts and the IMF in starbursts Triggering and Regulation of Star Formation: The Problem Introduction: Star Formation as a Nonlinear Process The schmidt Law in Normal Galaxies Star Formation Regimes in Interacting Galaxies Summary Triggering and Regulation of Starbusts: Theoretical Ideas Gravitational Star Formation Thresholds Cloud Collision Models Radial Transport of Gas: Clues from Barred Galaxies Simulations of Starbursts

Process for treating earth formations to be relatively inpermeable to formation water

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

Peacock, D.W.

1966-12-13

In a method for treatment of earth formations to make them relatively impermeable to formation water, high pH water is introduced through the bore into the formation under sufficient pressure to force the formation water out of the formation being treated. Thereafter, a high pH additive solution is introduced into the formation through the well bore. The pH of the additive solution is lowered in situ to precipitate the additive in the formation, thus shutting off the flow of water from the formation into the well. The additive is a tannin obtained from flavotannins, gallotannins, and mixed tannins. (7 claims)

The reticular formation.

PubMed

Horn, Anja K E

2006-01-01

The reticular formation of the brainstem contains functional cell groups that are important for the control of eye, head, or lid movements. The mesencephalic reticular formation is primarily involved in the control of vertical gaze, the paramedian pontine reticular formation in horizontal gaze, and the medullary pontine reticular formation in head movements and gaze holding. In this chapter, the locations, connections, and histochemical properties of the functional cell groups are reviewed and correlated with specific subdivisions of the reticular formation.

The Ponta Grossa Arch: A proposal for ts configuration and evolution from the interpretation of remote sensing data. M.S. Thesis

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Dealmeida, T. I. R.

1983-01-01

Visual analysis of MSS imagery was used to construct a map of dikes in a wide area of the Ponta Grossa Arch both in the Parana Basin and its basement. Analysis of the map by photographic methods defined the zone of highest density of the dikes, and some aspects of the longitudinal and transverse heterogeneities, as well as localized the apex of the Arch. Borders of the Arch were also suggested. Field investigations confirmed the position of the apex of the flexure on Palezoic sediments and pre-lava Mesozoic sediments. Controversial aspects of the relative absence of dikes in certain units or lithologies and the composition of intrusions surrounding the city of Castro were observed. The apparent synchronism between the activity of the Parana Basin and the Arch is discussed as well as the frequent inverse characteristics of vertical movements. The similarity of rocks in Brazil and Africa is also considered.

Northern Atlantic hurricanes possible connections with receded tides in Southern Brazilian and Uruguay Coast.

NASA Astrophysics Data System (ADS)

Hagen, M. T.; Azevedo, A. T.

2017-12-01

Harvey was formed around 17 august with maximum winds 40 miles/hour. At the moment, Irma formation started in 20 august faster becoming a hurricane category five. Some days before these two events, the Uruguay and Brazil coast suffered a recede in the oceans near Punta del Este and Rio Grande do Sul it happened in the week of 11 august. The energy accumulated in the recede of waters was not released by a tsunami and the water slowly was back to the shore. This event repeated at August 25, however at higher latitudes as in Parana and Sao Paulo. And consequent high tides in Chile again. The absence of a recurrent tsunami at the Brazilian coast indicates the energy accumulated from the recede ocean was released as a tsunami in the oceans, it became another huge hurricane formation as Jose and Katia. All those events pointed out for an atmospheric pressure disturbance on the Atlantic East Coast. In South America happened a suddenly increase at the atmospheric pressure which made the ocean waves receded for many days. A similar disturbance happened in Caribe area resulting in several huge hurricanes.

The History of Water Discharge in the Margaritifer Sinus Region of Mars

NASA Technical Reports Server (NTRS)

Grant, J. A.; Parker, T.

2001-01-01

Uzboi-Holden-Ladon-Margaritifer Valles and Samara and Parana-Loire Valles discharge into Margaritifer Basin during late-Noachian/early-Hesperian caused ponding, infiltration, and storage. Early-to-mid Hesperian release formed Margaritifer Chaos and Ares Valles. Additional information is contained in the original extended abstract.

Formation Design Strategy for SCOPE High-Elliptic Formation Flying Mission

NASA Technical Reports Server (NTRS)

Tsuda, Yuichi

2007-01-01

The new formation design strategy using simulated annealing (SA) optimization is presented. The SA algorithm is useful to survey a whole solution space of optimum formation, taking into account realistic constraints composed of continuous and discrete functions. It is revealed that this method is not only applicable for circular orbit, but also for high-elliptic orbit formation flying. The developed algorithm is first tested with a simple cart-wheel motion example, and then applied to the formation design for SCOPE. SCOPE is the next generation geomagnetotail observation mission planned in JAXA, utilizing a formation flying techonology in a high elliptic orbit. A distinctive and useful heuristics is found by investigating SA results, showing the effectiveness of the proposed design process.

A GAS-PHASE FORMATION ROUTE TO INTERSTELLAR TRANS-METHYL FORMATE

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

Cole, Callie A.; Wehres, Nadine; Yang Zhibo

2012-07-20

The abundance of methyl formate in the interstellar medium has previously been underpredicted by chemical models. Additionally, grain surface chemistry cannot account for the relative abundance of the cis- and trans-conformers of methyl formate, and the trans-conformer is not even formed at detectable abundance on these surfaces. This highlights the importance of studying formation pathways to methyl formate in the gas phase. The rate constant and branching fractions are reported for the gas-phase reaction between protonated methanol and formic acid to form protonated trans-methyl formate and water as well as adduct ion: Rate constants were experimentally determined using a flowingmore » afterglow-selected ion flow tube apparatus at 300 K and a pressure of 530 mTorr helium. The results indicate a moderate overall rate constant of (3.19 {+-} 0.39) Multiplication-Sign 10{sup -10} cm{sup 3} s{sup -1} ({+-} 1{sigma}) and an average branching fraction of 0.05 {+-} 0.04 for protonated trans-methyl formate and 0.95 {+-} 0.04 for the adduct ion. These experimental results are reinforced by ab initio calculations at the MP2(full)/aug-cc-pVTZ level of theory to examine the reaction coordinate and complement previous density functional theory calculations. This study underscores the need for continued observational studies of trans-methyl formate and for the exploration of other gas-phase formation routes to complex organic molecules.« less

DNA-RNA hybrid formation mediates RNAi-directed heterochromatin formation.

PubMed

Nakama, Mina; Kawakami, Kei; Kajitani, Takuya; Urano, Takeshi; Murakami, Yota

2012-03-01

Certain noncoding RNAs (ncRNAs) implicated in the regulation of chromatin structure associate with chromatin. During the formation of RNAi-directed heterochromatin in fission yeast, ncRNAs transcribed from heterochromatin are thought to recruit the RNAi machinery to chromatin for the formation of heterochromatin; however, the molecular details of this association are not clear. Here, using RNA immunoprecipitation assay, we showed that the heterochromatic ncRNA was associated with chromatin via the formation of a DNA-RNA hybrid and bound to the RNA-induced transcriptional silencing (RITS) complex. The presence of DNA-RNA hybrid in the cell was also confirmed by immunofluorescence analysis using anti-DNA-RNA hybrid antibody. Over-expression and depletion of RNase H in vivo decreased and increased the amount of DNA-RNA hybrid formed, respectively, and both disturbed heterochromatin. Moreover, DNA-RNA hybrid was formed on, and over-expression of RNase H inhibited the formation of, artificial heterochromatin induced by tethering of RITS to mRNA. These results indicate that heterochromatic ncRNAs are retained on chromatin via the formation of DNA-RNA hybrids and provide a platform for the RNAi-directed heterochromatin assembly and suggest that DNA-RNA hybrid formation plays a role in chromatic ncRNA function. © 2012 The Authors. Journal compilation © 2012 by the Molecular Biology Society of Japan/Blackwell Publishing Ltd.

Internalizing the Crisis of Cotton: Organizing Small Farmers in Eastern Paraguay.

ERIC Educational Resources Information Center

Bray, David; Borda, Dionisio

1988-01-01

Describes history, organizational problems and activities of Paraguay's Asociacion de Agricultores de Alto Parana (ASAGRAPA) and Programa de Ayuda Cristiana (PAC), farmer organizations. Details how cotton production losses forced farmers to invent new, varied markets, turning subsistence crops (peanuts, corn, and rice) into cash crops, while…

LGSOWG CCT format CCB document: The standard CCT family of tape formats

NASA Technical Reports Server (NTRS)

1979-01-01

The tape format standardization approach recommended by the committee on CCT standardization is described and defined. All rules and conventions required to employ the superstructure approach to the CCT family of tape formats are presented for users of remote sensing data and producer of user tapes and the superstructure records are specified. The standard for future tape format design is presented as a guide to designing data records of a particular tape format. An example is provided showing how to incorporate the superstructure into an already established tape format.

Autonomous Formation Flight

NASA Technical Reports Server (NTRS)

Schkolnik, Gerard S.; Cobleigh, Brent

2004-01-01

NASA's Strategic Plan for the Aerospace Technology Enterprise includes ambitious objectives focused on affordable air travel, reduced emissions, and expanded aviation-system capacity. NASA Dryden Flight Research Center, in cooperation with NASA Ames Research Center, the Boeing Company, and the University of California, Los Angeles, has embarked on an autonomous-formation-flight project that promises to make significant strides towards these goals. For millions of years, birds have taken advantage of the aerodynamic benefit of flying in formation. The traditional "V" formation flown by many species of birds (including gulls, pelicans, and geese) enables each of the trailing birds to fly in the upwash flow field that exists just outboard of the bird immediately ahead in the formation. The result for each trailing bird is a decrease in induced drag and thus a reduction in the energy needed to maintain a given speed. Hence, for migratory birds, formation flight extends the range of the system of birds over the range of birds flying solo. The Autonomous Formation Flight (AFF) Project is seeking to extend this symbiotic relationship to aircraft.

Planet Formation

NASA Astrophysics Data System (ADS)

Klahr, Hubert; Brandner, Wolfgang

2011-02-01

1. Historical notes on planet formation Bodenheimer; 2. The formation and evolution of planetary systems Bouwman et al.; 3. Destruction of protoplanetary disks by photoevaporation Richling, Hollenbach and Yorke; 4. Turbulence in protoplanetary accretion disks Klahr, Rozyczka, Dziourkevitch, Wunsch and Johansen; 5. The origin of solids in the early solar system Trieloff and Palme; 6. Experiments on planetesimal formation Wurm and Blum; 7. Dust coagulation in protoplanetary disks Henning, Dullemond, Wolf and Dominik; 8. The accretion of giant planet cores Thommes and Duncan; 9. Planetary transits: direct vision of extrasolar planets Lecavelier des Etangs and Vidal-Madjar; 10. The core accretion - gas capture model Hubickyj; 11. Properties of exoplanets Marcy, Fischer, Butler and Vogt; 12. Giant planet formation: theories meet observations Boss; 13. From hot Jupiters to hot Neptures … and below Lovis, Mayor and Udry; 14. Disk-planet interaction and migration Masset and Kley; 15. The Brown Dwarf - planet relation Bate; 16. From astronomy to astrobiology Brandner; 17. Overview and prospective Lin.

Planet Formation

NASA Astrophysics Data System (ADS)

Klahr, Hubert; Brandner, Wolfgang

2006-05-01

This volume addresses fundamental questions concerning the formation of planetary systems in general, and of our solar system in particular. Drawing from recent advances in observational, experimental, and theoretical research, it summarises our current understanding of the planet formation processes, and addresses major open questions and research issues. Chapters are written by leading experts in the field of planet formation and extrasolar planet studies. The book is based on a meeting held at Ringberg Castle in Bavaria, where experts gathered together to present and exchange their ideas and findings. It is a comprehensive resource for graduate students and researchers, and is written to be accessible to newcomers to the field.

Advanced Forensic Format: an Open Extensible Format for Disk Imaging

NASA Astrophysics Data System (ADS)

Garfinkel, Simson; Malan, David; Dubec, Karl-Alexander; Stevens, Christopher; Pham, Cecile

This paper describes the Advanced Forensic Format (AFF), which is designed as an alternative to current proprietary disk image formats. AFF offers two significant benefits. First, it is more flexible because it allows extensive metadata to be stored with images. Second, AFF images consume less disk space than images in other formats (e.g., EnCase images). This paper also describes the Advanced Disk Imager, a new program for acquiring disk images that compares favorably with existing alternatives.

Connecting the Cosmic Star Formation Rate with the Local Star Formation

NASA Astrophysics Data System (ADS)

Gribel, Carolina; Miranda, Oswaldo D.; Williams Vilas-Boas, José

2017-11-01

We present a model that unifies the cosmic star formation rate (CSFR), obtained through the hierarchical structure formation scenario, with the (Galactic) local star formation rate (SFR). It is possible to use the SFR to generate a CSFR mapping through the density probability distribution functions commonly used to study the role of turbulence in the star-forming regions of the Galaxy. We obtain a consistent mapping from redshift z˜ 20 up to the present (z = 0). Our results show that the turbulence exhibits a dual character, providing high values for the star formation efficiency (< \\varepsilon > ˜ 0.32) in the redshift interval z˜ 3.5{--}20 and reducing its value to < \\varepsilon > =0.021 at z = 0. The value of the Mach number ({{ M }}{crit}), from which < \\varepsilon > rapidly decreases, is dependent on both the polytropic index (Γ) and the minimum density contrast of the gas. We also derive Larson’s first law associated with the velocity dispersion (< {V}{rms}> ) in the local star formation regions. Our model shows good agreement with Larson’s law in the ˜ 10{--}50 {pc} range, providing typical temperatures {T}0˜ 10{--}80 {{K}} for the gas associated with star formation. As a consequence, dark matter halos of great mass could contain a number of halos of much smaller mass, and be able to form structures similar to globular clusters. Thus, Larson’s law emerges as a result of the very formation of large-scale structures, which in turn would allow the formation of galactic systems, including our Galaxy.

Precision Formation Keeping at L2 Using the Autonomous Formation Flying Sensor

NASA Technical Reports Server (NTRS)

McLoughlin, Terence H.; Campbell, Mark

2004-01-01

Recent advances in formation keeping for large numbers of spacecraft using the Autonomous Formation Flying are presented. This sensor, currently under development at JPL, has been identified as a key component in future formation flying spacecraft missions. The sensor provides accurate range and bearing measurements between pairs of spacecraft using GPS technology. Previous theoretical work by the authors has focused on developing a decentralized scheduling algorithm to control the tasking of such a sensor between the relative range and bearing measurements to each node in the formation. The resulting algorithm has been modified to include switching constraints in the sensor. This paper also presents a testbed for real time validation of a sixteen-node formation based on the Stellar Imager mission. Key aspects of the simulation include minimum fuel maneuvers based on free-body dynamics and a three body propagator for simulating the formation at L2.

Comet formation

NASA Astrophysics Data System (ADS)

Blum, J.

2014-07-01

There has been vast progress in our understanding of planetesimal formation over the past decades, owing to a number of laboratory experiments as well as to refined models of dust and ice agglomeration in protoplanetary disks. Coagulation rapidly forms cm-sized ''pebbles'' by direct sticking in collisions at low velocities (Güttler et al. 2010; Zsom et al. 2010). For the further growth, two model approaches are currently being discussed: (1) Local concentration of pebbles in nebular instabilities until gravitational instability occurs (Johansen et al. 2007). (2) A competition between fragmentation and mass transfer in collisions among the dusty bodies, in which a few ''lucky winners'' make it to planetesimal sizes (Windmark et al. 2012a,b; Garaud et al. 2013). Predictions of the physical properties of the resulting bodies in both models allow a distinction of the two formation scenarios of planetesimals. In particular, the tensile strength (i.e, the inner cohesion) of the planetesimals differ widely between the two models (Skorov & Blum 2012; Blum et al. 2014). While model (1) predicts tensile strengths on the order of ˜ 1 Pa, model (2) results in rather compactified dusty bodies with tensile strengths in the kPa regime. If comets are km-sized survivors of the planetesimal-formation era, they should in principle hold the secret of their formation process. Water ice is the prime volatile responsible for the activity of comets. Thermophysical models of the heat and mass transport close to the comet-nucleus surface predict water-ice sublimation temperatures that relate to maximum sublimation pressures well below the kPa regime predicted for formation scenario (2). Model (1), however, is in agreement with the observed dust and gas activity of comets. Thus, a formation scenario for cometesimals involving gravitational instability is favored (Blum et al. 2014).

A Remote Sensing Class Exercise To Study the Effects of "El Nino" in South America.

ERIC Educational Resources Information Center

Moxey, Lucas Eduardo

2002-01-01

Describes an undergraduate physical science laboratory course exercising the utilization of satellite imagery for studying the floods that resulted in the Parana River region in South America during El Nino (1997-1998), and examines vegetation cover and spectral profiles from the study area in order to further understand and assess the changes…

The formation of galaxies

NASA Technical Reports Server (NTRS)

Efstathiou, G.; Silk, J.

1983-01-01

Current models of galaxy formation are examined in a review of recent observational and theoretical studies. Observational data on elliptical galaxies, disk galaxies, luminosity functions, clustering, and angular fluctuations in the cosmic microwave background are summarized. Theoretical aspects discussed include the origin and early evolution of small fluctuations, matter and radiation fluctuations, the formation of large-scale structure, dissipationless galaxy formation, galaxy mergers, dissipational galaxy formation, and the implications of particle physics (GUTs, massive neutrinos, and gravitinos) for cosmology.

Simple Ontology Format (SOFT)

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

Sorokine, Alexandre

2011-10-01

Simple Ontology Format (SOFT) library and file format specification provides a set of simple tools for developing and maintaining ontologies. The library, implemented as a perl module, supports parsing and verification of the files in SOFt format, operations with ontologies (adding, removing, or filtering of entities), and converting of ontologies into other formats. SOFT allows users to quickly create ontologies using only a basic text editor, verify it, and portray it in a graph layout system using customized styles.

(Non) formation of methanol by direct hydrogenation of formate on copper catalysts

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

Yang, Yong; Mims, Charles A.; Disselkamp, Robert S.

2010-10-14

We have attempted to hydrogenate adsorbed formate species on copper catalysts to probe the importance of this postulated mechanistic step in methanol synthesis. Surface formate coverages up to 0.25 were produced at temperatures between 413K and 453K on supported (Cu/SiO2) copper and unsupported copper catalysts. The adlayers were produced by various methods including (1) steady state catalytic conditions in CO2-H2 (3:1, 6 bar) atmospheres, and (2) by exposure of the catalysts to formic acid. As reported in earlier work, the catalytic surface at steady state contains bidentate formate species with coverages up to saturation levels of ~ 0.25 at themore » low temperatures of this study. The reactivity of these formate adlayers was investigated at relevant reaction temperatures in atmospheres containing up to 6 bar H2 partial pressure by simultaneous mass spectrometry (MS) and infrared (IR) spectroscopy measurements. The yield of methanol during the attempted hydrogenation (“titration”) of these adlayers was insignificant (<0.2 mol % of the formate adlayer) even in dry hydrogen partial pressures up to 6 bar. Hydrogen titration of formate species produced from formic acid also failed to produce significant quantities of methanol, and attempted titration in gases consisting of CO-hydrogen mixtures or dry CO2 were also unproductive. The formate decomposition kinetics, measured by IR, were also unaffected by these changes in the gas composition. Similar experiments on unsupported copper also failed to show any methanol. From these results, we conclude that methanol synthesis on copper cannot result from the direct hydrogenation of (bidentate) formate species in simple steps involving adsorbed H species alone. Furthermore, experiments performed on both supported (Cu/SiO2) and unsupported copper catalysts gave similar results implying that the methanol synthesis reaction mechanism only involves metal surface chemistry. Pre-exposure of the bidentate formate adlayer to

Associations between forest fragmentation patterns and geneticstructure in Pfrimer’s Parakeet (Pyrrhura pfrimeri), an endangered endemic to central Brazil’s dry forests

USGS Publications Warehouse

Haig, Susan M.; Miller, Leonard F.; Bianchi, Carlos; Mullins, Thomas D.

2012-01-01

When habitat becomes fragmented, populations of species may become increasingly isolated. In the absence of habitat corridors, genetic structure may develop and populations risk reductions in genetic diversity from increased genetic drift and inbreeding. Deforestation of the Cerrado biome of Brazil, particularly of the dry forests within the Parana˜ River Basin, has incrementally occurred since the 1970s and increased forest fragmentation within the region. We performed landscape genetic analyses of Pfrimer’s parakeet (Pyrrhura pfrimeri), a globally endangered endemic to the region, to determine if forest fragmentation patterns were associated with genetic structuring in this species. We used previously generated satellite imagery that identified the locations of Parana˜ River Basin forest fragments in 1977, 1993/94, and 2008. Behavioral data quantifying the affinity of Pfrimer’s parakeet for forest habitat was used to parameterize empirically derived landscape conductance surfaces. Though genetic structure was observed among Pfrimer’s parakeet populations, no association between genetic and geographic distance was detected. Likewise, least cost path lengths, circuit theorybased resistance distances, and a new measure of least cost path length complexity could not be conclusively associated with genetic structure patterns. Instead, a new quantity that encapsulated connection redundancy from the 1977 forest fragmentation data provided the clearest associations with pairwise genetic differentiation patterns (Jost’s D: r = 0.72, P = 0.006; FST: r = 0.741, P = 0.001). Our analyses suggest a 35-year or more lag between deforestation and its effect on genetic structure. Because 66 % of the Parana˜ River Basin has been deforested since 1977, we expect that genetic structure will increase substantially among Pfrimer’s Parakeet populations in the future, especially if fragmentation continues at its current pace.

Vascular lumen formation.

PubMed

Lammert, Eckhard; Axnick, Jennifer

2012-04-01

The vascular system developed early in evolution. It is required in large multicellular organisms for the transport of nutrients, oxygen, and waste products to and from tissues. The vascular system is composed of hollow tubes, which have a high level of complexity in vertebrates. Vasculogenesis describes the de novo formation of blood vessels, e.g., aorta formation in vertebrate embryogenesis. In contrast, angiogenesis is the formation of blood vessels from preexisting ones, e.g., sprouting of intersomitic blood vessels from the aorta. Importantly, the lumen of all blood vessels in vertebrates is lined and formed by endothelial cells. In both vasculogenesis and angiogenesis, lumen formation takes place in a cord of endothelial cells. It involves a complex molecular mechanism composed of endothelial cell repulsion at the cell-cell contacts within the endothelial cell cords, junctional rearrangement, and endothelial cell shape change. As the vascular system also participates in the course of many diseases, such as cancer, stroke, and myocardial infarction, it is important to understand and make use of the molecular mechanisms of blood vessel formation to better understand and manipulate the pathomechanisms involved.

Formation of methyl formate in comets by irradiation of methanol-bearing ices

NASA Astrophysics Data System (ADS)

Modica, P.; Palumbo, M. E.; Strazzulla, G.

2012-12-01

Methyl formate is a complex organic molecule considered potentially relevant as precursor of biologically active molecules. It has been observed in several astrophysical environments, such as hot cores, hot corinos, and comets. The processes that drive the formation of molecules in cometary ices are poorly understood. In particular it is not yet clear if molecules are directly accreted from the pre-solar nebula to form comets or are formed after accretion. The present work analyzes the possible role of cosmic ion irradiation and radioactive decay in methyl formate formation in methanol-bearing ices. The results indicate that cosmic ion irradiation can account for about 12% of the methyl formate observed in comet Hale-Bopp, while radioactive decay can account for about 6% of this amount. The need of new data coming from earth based and space observational projects as well as from laboratory experiments is outlined.

Focus on Formative Feedback

ERIC Educational Resources Information Center

Shute, Valerie J.

2008-01-01

This article reviews the corpus of research on feedback, with a focus on formative feedback--defined as information communicated to the learner that is intended to modify his or her thinking or behavior to improve learning. According to researchers, formative feedback should be nonevaluative, supportive, timely, and specific. Formative feedback is…

Public security female workers at the coast of Paraná, Brazil: intersections of gender, work, violence(s), and health.

PubMed

Schneider, Daniele; Signorelli, Marcos Claudio; Pereira, Pedro Paulo Gomes

2017-09-01

This study aimed to promote visibility of women working in public security along the Parana coast, articulating issues of gender, violence(s), and the health-disease process. The methodology was qualitative, through an ethnographic research which included 50 women (civilians, military policewomen, and prison officers) from municipalities along the Parana coast, between March 2014 and March 2015. Results revealed: 1) the dilemmas that these women are subjected to, facing the seasonal dynamics in the field of public security in the region; 2) exposure to violence (mainly institutional and gender-based) and its impact on these women's health; 3) power relations, marked by corporations' hierarchies and gender asymmetries between men and women in professional settings. In summary, this research highlighted the need to promote visibility of women working in public security institutions, considering the impact of violence and gender inequalities in their personal and professional lives, including the resistance and rearrangements promoted by these women in the institutions in response to their presence in a hegemonic and traditionally male environment.

MODIS Data Assimilation in the CROPGRO model for improving soybean yield estimations

NASA Astrophysics Data System (ADS)

Richetti, J.; Monsivais-Huertero, A.; Ahmad, I.; Judge, J.

2017-12-01

Soybean is one of the main agricultural commodities in the world. Thus, having better estimates of its agricultural production is important. Improving the soybean crop models in Brazil is crucial for better understanding of the soybean market and enhancing decision making, because Brazil is the second largest soybean producer in the world, Parana state is responsible for almost 20% of it, and by itself would be the fourth greatest soybean producer in the world. Data assimilation techniques provide a method to improve spatio-temporal continuity of crops through integration of remotely sensed observations and crop growth models. This study aims to use MODIS EVI to improve DSSAT-CROPGRO soybean yield estimations in the Parana state, southern Brazil. The method uses the Ensemble Kalman filter which assimilates MODIS Terra and Aqua combined products (MOD13Q1 and MYD13Q1) into the CROPGRO model to improve the agricultural production estimates through update of light interception data over time. Expected results will be validated with monitored commercial farms during the period of 2013-2014.

Earth Observations taken by the Expedition 10 crew

NASA Image and Video Library

2004-10-25

ISS010-E-05072 (25 October 2004) --- Ibera Swamp topography in northeast Argentina is featured in this image photographed by an Expedition 10 crewmember on the International Space Station (ISS). The central lake in this image is one of hundreds in the Ibera swamplands that were formed by South America’s second largest river, the Parana. Although this great river now lies 120 kilometers to the north, its channel has swung over a great “inland delta” in the recent geological past, according to NASA scientists studying the Expedition 10 photo collection. This and other lakes were captured in this photograph as the sunglint point passed over this remote but vast swampland in northeast Argentina. The glint pattern shows winds ruffling the water surfaces. The lakes in this image lie within side channels of the Parana formed when it flowed through this region. The central lake in the image is about 2 kilometers long. Forest, swamp and prairie vegetation types outline the low topography which consists of lakes, low swells and depressions.

Implementation of AAPG exchange format

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

Keiser, K.; Guerrero, I.

1989-03-01

The American Association of Petroleum Geologists (AAPG) has proposed a format for exchanging geologic and other petroleum data. The AAPG Computer Applications Committee approved the proposal at the March 1988 AAPG annual meeting in Houston, Texas. By adopting this format, data input into application software and data exchange between software packages are greatly simplified. Benefits to both users and suppliers of software are substantial. The AAPG exchange format supports a flexible, generic data structure. This flexibility allows application software to use the standard format for storing internal control data. In some cases, extensions to the standard format, such as separationmore » of header and data files and use of data delimiters, permits the use of AAPG format translator programs on data that were defined and generated before the emergence of the exchange format. Translation software, programmed in C, has been written and contributes to successful implementation of the AAPG exchange format in application software.« less

Formation Algorithms and Simulation Testbed

NASA Technical Reports Server (NTRS)

Wette, Matthew; Sohl, Garett; Scharf, Daniel; Benowitz, Edward

2004-01-01

Formation flying for spacecraft is a rapidly developing field that will enable a new era of space science. For one of its missions, the Terrestrial Planet Finder (TPF) project has selected a formation flying interferometer design to detect earth-like planets orbiting distant stars. In order to advance technology needed for the TPF formation flying interferometer, the TPF project has been developing a distributed real-time testbed to demonstrate end-to-end operation of formation flying with TPF-like functionality and precision. This is the Formation Algorithms and Simulation Testbed (FAST) . This FAST was conceived to bring out issues in timing, data fusion, inter-spacecraft communication, inter-spacecraft sensing and system-wide formation robustness. In this paper we describe the FAST and show results from a two-spacecraft formation scenario. The two-spacecraft simulation is the first time that precision end-to-end formation flying operation has been demonstrated in a distributed real-time simulation environment.

Formate production through biocatalysis

PubMed Central

Alissandratos, Apostolos; Kim, Hye-Kyung; Easton, Christopher J

2013-01-01

The generation of formate from CO2 provides a method for sequestration of this greenhouse gas as well as the production of a valuable commodity chemical and stabilized form of hydrogen fuel. Formate dehydrogenases are enzymes with the potential to catalyze this reaction; however they generally favor the reverse process, i.e., formate oxidation. By contrast, the formate dehydrogenase of the acetogen Clostridium carboxidivorans has been found to preferentially catalyze the reduction of CO2. This is in accord with its natural role to introduce CO2 as a carbon source in the Wood-Ljungdahl pathway. The direction of catalysis derives from the enzyme’s low affinity for formate. This enzyme is therefore an excellent candidate for biotechnological applications aimed at producing formic acid and derivative chemicals from CO2. PMID:23841981

Feedback in formative OSCEs: comparison between direct observation and video-based formats

PubMed Central

Junod Perron, Noëlle; Louis-Simonet, Martine; Cerutti, Bernard; Pfarrwaller, Eva; Sommer, Johanna; Nendaz, Mathieu

2016-01-01

Introduction Medical students at the Faculty of Medicine, University of Geneva, Switzerland, have the opportunity to practice clinical skills with simulated patients during formative sessions in preparation for clerkships. These sessions are given in two formats: 1) direct observation of an encounter followed by verbal feedback (direct feedback) and 2) subsequent review of the videotaped encounter by both student and supervisor (video-based feedback). The aim of the study was to evaluate whether content and process of feedback differed between both formats. Methods In 2013, all second- and third-year medical students and clinical supervisors involved in formative sessions were asked to take part in the study. A sample of audiotaped feedback sessions involving supervisors who gave feedback in both formats were analyzed (content and process of the feedback) using a 21-item feedback scale. Results Forty-eight audiotaped feedback sessions involving 12 supervisors were analyzed (2 direct and 2 video-based sessions per supervisor). When adjusted for the length of feedback, there were significant differences in terms of content and process between both formats; the number of communication skills and clinical reasoning items addressed were higher in the video-based format (11.29 vs. 7.71, p=0.002 and 3.71 vs. 2.04, p=0.010, respectively). Supervisors engaged students more actively during the video-based sessions than during direct feedback sessions (self-assessment: 4.00 vs. 3.17, p=0.007; active problem-solving: 3.92 vs. 3.42, p=0.009). Students made similar observations and tended to consider that the video feedback was more useful for improving some clinical skills. Conclusion Video-based feedback facilitates discussion of clinical reasoning, communication, and professionalism issues while at the same time actively engaging students. Different time and conceptual frameworks may explain observed differences. The choice of feedback format should depend on the educational

Feedback in formative OSCEs: comparison between direct observation and video-based formats.

PubMed

Junod Perron, Noëlle; Louis-Simonet, Martine; Cerutti, Bernard; Pfarrwaller, Eva; Sommer, Johanna; Nendaz, Mathieu

2016-01-01

Medical students at the Faculty of Medicine, University of Geneva, Switzerland, have the opportunity to practice clinical skills with simulated patients during formative sessions in preparation for clerkships. These sessions are given in two formats: 1) direct observation of an encounter followed by verbal feedback (direct feedback) and 2) subsequent review of the videotaped encounter by both student and supervisor (video-based feedback). The aim of the study was to evaluate whether content and process of feedback differed between both formats. In 2013, all second- and third-year medical students and clinical supervisors involved in formative sessions were asked to take part in the study. A sample of audiotaped feedback sessions involving supervisors who gave feedback in both formats were analyzed (content and process of the feedback) using a 21-item feedback scale. Forty-eight audiotaped feedback sessions involving 12 supervisors were analyzed (2 direct and 2 video-based sessions per supervisor). When adjusted for the length of feedback, there were significant differences in terms of content and process between both formats; the number of communication skills and clinical reasoning items addressed were higher in the video-based format (11.29 vs. 7.71, p= 0.002 and 3.71 vs. 2.04, p= 0.010, respectively). Supervisors engaged students more actively during the video-based sessions than during direct feedback sessions (self-assessment: 4.00 vs. 3.17, p= 0.007; active problem-solving: 3.92 vs. 3.42, p= 0.009). Students made similar observations and tended to consider that the video feedback was more useful for improving some clinical skills. Video-based feedback facilitates discussion of clinical reasoning, communication, and professionalism issues while at the same time actively engaging students. Different time and conceptual frameworks may explain observed differences. The choice of feedback format should depend on the educational goal.

Formative Assessment Probes: Is It a Rock? Continuous Formative Assessment

ERIC Educational Resources Information Center

Keeley, Page

2013-01-01

A lesson plan is provided for a formative assessment probe entitled "Is It a Rock?" This probe is designed for teaching elementary school students about rocks through the use of a formative assessment classroom technique (FACT) known as the group Frayer Model. FACT activates students' thinking about a concept and can be used to…

Comparing student understanding of quantum physics when embedding multimodal representations into two different writing formats: Presentation format versus summary report format

NASA Astrophysics Data System (ADS)

Gunel, Murat; Hand, Brian; Gunduz, Sevket

2006-11-01

Physics as a subject for school students requires an understanding and ability to move between different modes of representation for the concepts under review. However, the inability of students to have a multimodal understanding of the concepts is seen as restricting their understandings of the concepts. The aim of this study was to explore the effectiveness of using writing-to-learn strategies that required students to embed multimodal representations of the concepts. In particular, the study compared a presentation format with a summary report format for students learning quantum theory. A pre-post test design was used to compare performances of these two groups across two units. For unit 1, students' scores from groups that completed either a presentation format (PowerPoint presentation) or a summary report format (chapter summary) were compared. No limits were placed on the amount of text or the number of representations used. For unit 2, products of both groups were constructed for an audience of year 10 students. The presentation format group (PowerPoint) was limited to 15 slides, with a maximum of 10 words displayed per slide; a script was written to accompany the presentation. Slides could include graphical and mathematical formulae; however, the text could not. The summary report format group that wrote out its explanations was limited to four pages and was required to incorporate multimodal representations. Results indicated that for both units students using the presentation format group scored significantly better on tests than the summary report format group. The effect size difference between the groups increased for the second unit, indicating that more practice was leading to better student understanding of the physics concepts.

Better Formative Assessment

ERIC Educational Resources Information Center

Clinchot, Michael; Ngai, Courtney; Huie, Robert; Talanquer, Vicente; Lambertz, Jennifer; Banks, Gregory; Weinrich, Melissa; Lewis, Rebecca; Pelletier, Pamela; Sevian, Hannah

2017-01-01

Formative assessment has been defined as the process "to recognize and respond to student learning to enhance that learning during the learning." Formative assessment helps teachers identify strengths and weaknesses in their students' understanding, focuses students' attention on relevant information and ideas, and provides scaffolds…

Aspects of Writing and Identity

ERIC Educational Resources Information Center

Correa, Djane Antonucci

2011-01-01

This text is the result of reflections that originated in the discussions of a study group composed of undergraduate and postgraduate students in a language lab at a public university in the interior of the state of Parana, in the south of Brazil. This study specifically addresses some considerations about the connections that can be established…

The Formation of Mini-Neptunes

NASA Astrophysics Data System (ADS)

Venturini, Julia; Helled, Ravit

2017-10-01

Mini-Neptunes seem to be common planets. In this work we investigate the possible formation histories and predicted occurrence rates of mini-Neptunes, assuming that the planets form beyond the iceline. We consider pebble and planetesimal accretion accounting for envelope enrichment and two different opacity conditions. We find that the formation of mini-Neptunes is a relatively frequent output when envelope enrichment by volatiles is included, and that there is a “sweet spot” for mini-Neptune formation with a relatively low solid accretion rate of ˜10-6 M ⊕ yr-1. This rate is typical for low/intermediate-mass protoplanetary disks and/or disks with low metallicities. With pebble accretion, envelope enrichment and high opacity favor the formation of mini-Neptunes, with more efficient formation at large semimajor axes (˜30 au) and low disk viscosities. For planetesimal accretion, such planets can also form without enrichment, with the opacity being a key aspect in the growth history and favorable formation location. Finally, we show that the formation of Neptune-like planets remains a challenge for planet formation theories.

Reconsidering formative measurement.

PubMed

Howell, Roy D; Breivik, Einar; Wilcox, James B

2007-06-01

The relationship between observable responses and the latent constructs they are purported to measure has received considerable attention recently, with particular focus on what has become known as formative measurement. This alternative to reflective measurement in the area of theory-testing research is examined in the context of the potential for interpretational confounding and a construct's ability to function as a point variable within a larger model. Although these issues have been addressed in the traditional reflective measurement context, the authors suggest that they are particularly relevant in evaluating formative measurement models. On the basis of this analysis, the authors conclude that formative measurement is not an equally attractive alternative to reflective measurement and that whenever possible, in developing new measures or choosing among alternative existing measures, researchers should opt for reflective measurement. In addition, the authors provide guidelines for researchers dealing with existing formative measures. Copyright 2007 APA, all rights reserved.

Photogeneration of active formate decomposition catalysts to produce hydrogen from formate and water

DOEpatents

King, Jr., Allen D.; King, Robert B.; Sailers, III, Earl L.

1983-02-08

A process for producing hydrogen from formate and water by photogenerating an active formate decomposition catalyst from transition metal carbonyl precursor catalysts at relatively low temperatures and otherwise mild conditions is disclosed. Additionally, this process may be expanded to include the generation of formate from carbon monoxide and hydroxide such that the result is the water gas shift reaction.

Catalysis of Dialanine Formation by Glycine in the Salt-Induced Peptide Formation Reaction.

NASA Astrophysics Data System (ADS)

Suwannachot, Yuttana; Rode, Bernd M.

1998-02-01

Mutual catalysis of amino acids in the salt-induced peptide formation (SIPF) reaction is demonstrated for the case of glycine/alanine. The presence of glycine enhances dialanine formation by a factor up to 50 and enables dialanine formation at much lower alanine concentrations. The actual amounts of glycine play an important role for this catalytic effect, the optimal glycine concentration is 1/8 of the alanine concentration. The mechanism appears to be based on the formation of the intermediate Gly-Ala-Ala tripeptide, connected to one coordination site of copper(II) ion, and subsequent hydrolysis to dialanine and glycine.

Catalysis of dialanine formation by glycine in the salt-induced peptide formation reaction.

PubMed

Suwannachot, Y; Rode, B M

1998-02-01

Mutual catalysis of amino acids in the salt-induced peptide formation (SIPF) reaction is demonstrated for the case of glycine/alanine. The presence of glycine enhances dialanine formation by a factor up to 50 and enables dialanine formation at much lower alanine concentrations. The actual amounts of glycine play an important role for this catalytic effect, the optimal glycine concentration is 1/8 of the alanine concentration. The mechanism appears to be based on the formation of the intermediate Gly-Ala-Ala tripeptide, connected to one coordination site of copper(II) ion, and subsequent hydrolysis to dialanine and glycine.

Planet Formation in Binaries

NASA Astrophysics Data System (ADS)

Thebault, P.; Haghighipour, N.

Spurred by the discovery of numerous exoplanets in multiple systems, binaries have become in recent years one of the main topics in planet formation research. Numerous studies have investigated to what extent the presence of a stellar companion can affect the planet formation process. Such studies have implications that can reach beyond the sole context of binaries, as they allow to test certain aspects of the planet formation scenario by submitting them to extreme environments. We review here the current understanding on this complex problem. We show in particular how each of the different stages of the planet-formation process is affected differently by binary perturbations. We focus especially on the intermediate stage of kilometre-sized planetesimal accretion, which has proven to be the most sensitive to binarity and for which the presence of some exoplanets observed in tight binaries is difficult to explain by in-situ formation following the "standard" planet-formation scenario. Some tentative solutions to this apparent paradox are presented. The last part of our review presents a thorough description of the problem of planet habitability, for which the binary environment creates a complex situation because of the presence of two irradation sources of varying distance.

The Formation of Galactic Bulges

NASA Astrophysics Data System (ADS)

Carollo, C. Marcella; Ferguson, Henry C.; Wyse, Rosemary F. G.

2000-03-01

Part I. Introduction: What are galactic bulges?; Part II. The Epoch of Bulge Formation: Origin of bulges; Deep sub-mm surveys: High-z ULIRGs and the formation of spheroids; Ages and metallicities for stars in the galactic bulge; Integrated stellar populations of bulges: First results; HST-NICMOS observations of galactic bulges: Ages and dust; Inside-out bulge formation and the origin of the Hubble sequence; Part III. The Timescales of Bulge Formation: Constraints on the bulge formation timescale from stellar populations; Bulge building with mergers and winds; Role of winds, starbursts, and activity in bulge formation; Dynamical timescales of bulge formation; Part IV. Physical Processes in Bulge Formation: the role of bars for secular bulge formation; Bars and boxy/peanut-shaped bulges: an observational point of view; Boxy- and peanut-shaped bulges; A new class of bulges; The role of secondary bars in bulge formation; Radial transport of molecular gas to the nuclei of spiral galaxies; Dynamical evolution of bulge shapes; Two-component stellar systems: Phase-space constraints; Central NGC 2146 - a firehose-type bending instability?; Bulge formation: the role of the multi-phase ISM; Global evolution of a self-gravitating multi-phase ISM in the central kpc region of galaxies; Part V. Bulge Phenomenology: Bulge-disk decomposition of spiral galaxies in the near-infrared; The triaxial bulge of NGC 1371; The bulge-disk orthogonal decoupling in galaxies: NGC 4698 and NGC 4672; The kinematics and the origin of the ionized gas in NGC 4036; Optically thin thermal plasma in the galactic bulge; X-ray properties of bulges; The host galaxies of radio-loud AGN; The centers of radio-loud early-type galaxies with HST; Central UV spikes in two galactic spheroids; Conference summary: where do we stand?

Earth observation image data format

NASA Technical Reports Server (NTRS)

Sos, J. Y.

1976-01-01

A flexible format for computer compatable tape (CCT) containing multispectral earth observation sensor data is described. The driving functions which comprise the data format requirements are summarized and general data format guidelines are discussed.

Formate auxotroph of Methanobacterium thermoautotrophicum Marburg.

PubMed Central

Tanner, R S; McInerney, M J; Nagle, D P

1989-01-01

A formate-requiring auxotroph of Methanobacterium thermoautotrophicum Marburg was isolated after hydroxylamine mutagenesis and bacitracin selection. The requirement for formate is unique and specific; combined pools of other volatile fatty acids, amino acids, vitamins, and nitrogen bases did not substitute for formate. Compared with those of the wild type, cell extracts of the formate auxotroph were deficient in formate dehydrogenase activity, but cells of all of the strains examined catalyzed a formate-carbon dioxide exchange activity. All of the strains examined took up a small amount (200 to 260 mumol/liter) of formate (3 mM) added to medium. The results of the study of this novel auxotroph indicate a role for formate in biosynthetic reactions in this methanogen. Moreover, because methanogenesis from H2-CO2 is not impaired in the mutant, free formate is not an intermediate in the reduction of CO2 to CH4. PMID:2687241

Formation of Bidisperse Particle Clouds

NASA Astrophysics Data System (ADS)

Er, Jenn Wei; Zhao, Bing; Law, Adrian W. K.; Adams, E. Eric

2014-11-01

When a group of dense particles is released instantaneously into water, their motion has been conceptualized as a circulating particle thermal (Ruggerber 2000). However, Wen and Nacamuli (1996) observed the formation of particle clumps characterized by a narrow, fast moving core shedding particles into wakes. They observed the clump formation even for particles in the non-cohesive range as long as the source Rayleigh number was large (Ra > 1E3) or equivalently the source cloud number (Nc) was small (Nc < 3.2E2). This physical phenomenon has been investigated by Zhao et al. (2014) through physical experiments. They proposed the theoretical support for Nc dependence and categorized the formation processes into cloud formation, transitional regime and clump formation. Previous works focused mainly on the behavior of monodisperse particles. The present study further extends the experimental investigation to the formation process of bidisperse particles. Experiments are conducted in a glass tank with a water depth of 90 cm. Finite amounts of sediments with various weight proportions between coarser and finer particles are released from a cylindrical tube. The Nc being tested ranges from 6E-3 to 9.9E-2, which covers all the three formation regimes. The experimental results showed that the introduction of coarse particles promotes cloud formation and reduce the losses of finer particles into the wake. More quantitative descriptions of the effects of source conditions on the formation processes will be presented during the conference.

Building Format-Agnostic Metadata Repositories

NASA Astrophysics Data System (ADS)

Cechini, M.; Pilone, D.

2010-12-01

This presentation will discuss the problems that surround persisting and discovering metadata in multiple formats; a set of tenets that must be addressed in a solution; and NASA’s Earth Observing System (EOS) ClearingHOuse’s (ECHO) proposed approach. In order to facilitate cross-discipline data analysis, Earth Scientists will potentially interact with more than one data source. The most common data discovery paradigm relies on services and/or applications facilitating the discovery and presentation of metadata. What may not be common are the formats in which the metadata are formatted. As the number of sources and datasets utilized for research increases, it becomes more likely that a researcher will encounter conflicting metadata formats. Metadata repositories, such as the EOS ClearingHOuse (ECHO), along with data centers, must identify ways to address this issue. In order to define the solution to this problem, the following tenets are identified: - There exists a set of ‘core’ metadata fields recommended for data discovery. - There exists a set of users who will require the entire metadata record for advanced analysis. - There exists a set of users who will require a ‘core’ set of metadata fields for discovery only. - There will never be a cessation of new formats or a total retirement of all old formats. - Users should be presented metadata in a consistent format. ECHO has undertaken an effort to transform its metadata ingest and discovery services in order to support the growing set of metadata formats. In order to address the previously listed items, ECHO’s new metadata processing paradigm utilizes the following approach: - Identify a cross-format set of ‘core’ metadata fields necessary for discovery. - Implement format-specific indexers to extract the ‘core’ metadata fields into an optimized query capability. - Archive the original metadata in its entirety for presentation to users requiring the full record. - Provide on

What Determines Star Formation Rates?

NASA Astrophysics Data System (ADS)

Evans, Neal John

2017-06-01

The relations between star formation and gas have received renewed attention. We combine studies on scales ranging from local (within 0.5 kpc) to distant galaxies to assess what factors contribute to star formation. These include studies of star forming regions in the Milky Way, the LMC, nearby galaxies with spatially resolved star formation, and integrated galaxy studies. We test whether total molecular gas or dense gas provides the best predictor of star formation rate. The star formation ``efficiency," defined as star formation rate divided by mass, spreads over a large range when the mass refers to molecular gas; the standard deviation of the log of the efficiency decreases by a factor of three when the mass of relatively dense molecular gas is used rather than the mass of all the molecular gas. We suggest ways to further develop the concept of "dense gas" to incorporate other factors, such as turbulence.

Method of fracturing a geological formation

DOEpatents

Johnson, James O.

1990-01-01

An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

[Rural-urban population redistribution between 1970 and 1980 (a micro-regional analysis)].

PubMed

Costa, M A

1982-01-01

Changes in rural-urban population distribution in Brazil from 1970 to 1980 are analyzed using census data. Trends examined include spatial redistribution throughout the country, rapid urbanization, the decline in the size of the rural population in the state of Parana, agricultural expansion in the northern and central-western regions, and the increase of the rural population within metropolitan areas. (summary in ENG)

Method for measuring pollutant formation

NASA Technical Reports Server (NTRS)

Stickler, David B. (Inventor); Annen, Kurt (Inventor)

2001-01-01

Diagnostic methods for determining an instantaneous rate of pollutant formation in a combustion system are based on measurement of chemiluminescence intensity generated simultaneously with the formation of the pollutant. The chemiluminescent signal is generated by an analog reaction which occurs in parallel with a key step in the formation of a specific pollutant of interest. The connection between the analog reaction and the pollution reaction is such that the chemiluminescent signal indicates the local, instantaneous formation rate of the pollutant of interest.

Formative Assessment: Simply, No Additives

ERIC Educational Resources Information Center

Roskos, Kathleen; Neuman, Susan B.

2012-01-01

Among the types of assessment the closest to daily reading instruction is formative assessment. In contrast to summative assessment, which occurs after instruction, formative assessment involves forming judgments frequently in the flow of instruction. Key features of formative assessment include identifying gaps between where students are and…

Treating tar sands formations with dolomite

DOEpatents

Vinegar, Harold J.; Karanikas, John Michael

2010-06-08

Methods for treating a tar sands formation are described herein. The tar sands formation may include dolomite and hydrocarbons. Methods may include providing heat at less than the decomposition temperature of dolomite from one or more heaters to at least a portion of the formation. At least some of the hydrocarbon fluids are mobilized in the formation. At least some of the hydrocarbon fluids may be produced from the formation.

Stacked Star Formation Rate Profiles of Bursty Galaxies Exhibit “Coherent” Star Formation

NASA Astrophysics Data System (ADS)

Orr, Matthew E.; Hayward, Christopher C.; Nelson, Erica J.; Hopkins, Philip F.; Faucher-Giguère, Claude-André; Kereš, Dušan; Chan, T. K.; Schmitz, Denise M.; Miller, Tim B.

2017-11-01

In a recent work based on 3200 stacked Hα maps of galaxies at z˜ 1, Nelson et al. find evidence for “coherent star formation”: the stacked star formation rate (SFR) profiles of galaxies above (below) the “star formation main sequence” (MS) are above (below) that of galaxies on the MS at all radii. One might interpret this result as inconsistent with highly bursty star formation and evidence that galaxies evolve smoothly along the MS rather than crossing it many times. We analyze six simulated galaxies at z˜ 1 from the Feedback in Realistic Environments (FIRE) project in a manner analogous to the observations to test whether the above interpretations are correct. The trends in stacked SFR profiles are qualitatively consistent with those observed. However, SFR profiles of individual galaxies are much more complex than the stacked profiles: the former can be flat or even peak at large radii because of the highly clustered nature of star formation in the simulations. Moreover, the SFR profiles of individual galaxies above (below) the MS are not systematically above (below) those of MS galaxies at all radii. We conclude that the time-averaged coherent star formation evident stacks of observed galaxies is consistent with highly bursty, clumpy star formation of individual galaxies and is not evidence that galaxies evolve smoothly along the MS.

Formation of the formate-nitrate electron transport pathway from inactive components in Escherichia coli.

PubMed Central

Scott, R H; DeMoss, J A

1976-01-01

When Escherichia coli was grown on medium containing 10 mM tungstate the formation of active formate dehydrogenase, nitrate reductase, and the complete formate-nitrate electron transport pathway was inhibited. Incubation of the tungstate-grown cells with 1 mM molybdate in the presence of chloramphenicol led to the rapid activation of both formate dehydrogenase and nitrate reductase, and, after a considerable lag, the complete electron transport pathway. Protein bands which corresponded to formate dehydrogenase and nitrate reductase were identified on polyacrylamide gels containing Triton X-100 after the activities were released from the membrane fraction and partially purified Cytochrome b1 was associated with the protein band corresponding to formate dehydrogenase but was not found elsewhere on the gels. When a similar fraction was prepared from cells grown on 10 mM tungstate, an inactive band corresponding to formate dehydrogenase was not observed on polyacrylamide gels; rather, a new faster migrating band was present. Cytochrome b1 was not associated with this band nor was it found anywhere else on the gels. This new band disappeared when the tungstate-grown cells were incubated with molybdate in the presence of chloramphenicol. The formate dehydrogenase activity which was formed, as well as a corresponding protein band, appeared at the original position on the gels. Cytochrome b1 was again associated with this band. The protein band which corresponded to nitrate reductase also was severely depressed in the tungstate-grown cells and a new faster migrating band appeared on the polyacrylamide gels. Upon activation of the nitrate reductase by incubation of the cells with molybdate, the new band diminished and protein reappeared at the original position. Most of the nitrate reductase activity which was formed appeared at the original position of nitrate reductase on gels although some was present at the position of the inactive band formed by tungstate-grown cells

Star Formation in Galaxies

NASA Technical Reports Server (NTRS)

1987-01-01

Topics addressed include: star formation; galactic infrared emission; molecular clouds; OB star luminosity; dust grains; IRAS observations; galactic disks; stellar formation in Magellanic clouds; irregular galaxies; spiral galaxies; starbursts; morphology of galactic centers; and far-infrared observations.

Methodology of ETV Formative Evaluation.

ERIC Educational Resources Information Center

Duby, Aliza

Formative evaluation is discussed as it relates to educational television (ETV). Formative evaluation, used to improve a project during its development, is especially valuable in the production of television programs. Methods useful in the formative evaluation of ETV are: (1) try-out studies; (2) learner verification and revision; (3)…

Formative Research in Educational Media.

ERIC Educational Resources Information Center

Hodapp, Timothy

This paper distinguishes between basic research, applied research, and evaluation. Evaluation is broken down into two types: summative and formative. The limitations of formative research are presented, followed by a discussion of the value of the formative researcher participating in the product planning process. The types of data which formative…

Motion Predicts Clinical Callus Formation

PubMed Central

Elkins, Jacob; Marsh, J. Lawrence; Lujan, Trevor; Peindl, Richard; Kellam, James; Anderson, Donald D.; Lack, William

2016-01-01

Background: Mechanotransduction is theorized to influence fracture-healing, but optimal fracture-site motion is poorly defined. We hypothesized that three-dimensional (3-D) fracture-site motion as estimated by finite element (FE) analysis would influence callus formation for a clinical series of supracondylar femoral fractures treated with locking-plate fixation. Methods: Construct-specific FE modeling simulated 3-D fracture-site motion for sixty-six supracondylar femoral fractures (OTA/AO classification of 33A or 33C) treated at a single institution. Construct stiffness and directional motion through the fracture were investigated to assess the validity of construct stiffness as a surrogate measure of 3-D motion at the fracture site. Callus formation was assessed radiographically for all patients at six, twelve, and twenty-four weeks postoperatively. Univariate and multivariate linear regression analyses examined the effects of longitudinal motion, shear (transverse motion), open fracture, smoking, and diabetes on callus formation. Construct types were compared to determine whether their 3-D motion profile was associated with callus formation. Results: Shear disproportionately increased relative to longitudinal motion with increasing bridge span, which was not predicted by our assessment of construct stiffness alone. Callus formation was not associated with open fracture, smoking, or diabetes at six, twelve, or twenty-four weeks. However, callus formation was associated with 3-D fracture-site motion at twelve and twenty-four weeks. Longitudinal motion promoted callus formation at twelve and twenty-four weeks (p = 0.017 for both). Shear inhibited callus formation at twelve and twenty-four weeks (p = 0.017 and p = 0.022, respectively). Titanium constructs with a short bridge span demonstrated greater longitudinal motion with less shear than did the other constructs, and this was associated with greater callus formation (p < 0.001). Conclusions: In this study of

Inside-out Planet Formation. IV. Pebble Evolution and Planet Formation Timescales

NASA Astrophysics Data System (ADS)

Hu, Xiao; Tan, Jonathan C.; Zhu, Zhaohuan; Chatterjee, Sourav; Birnstiel, Tilman; Youdin, Andrew N.; Mohanty, Subhanjoy

2018-04-01

Systems with tightly packed inner planets (STIPs) are very common. Chatterjee & Tan proposed Inside-out Planet Formation (IOPF), an in situ formation theory, to explain these planets. IOPF involves sequential planet formation from pebble-rich rings that are fed from the outer disk and trapped at the pressure maximum associated with the dead zone inner boundary (DZIB). Planet masses are set by their ability to open a gap and cause the DZIB to retreat outwards. We present models for the disk density and temperature structures that are relevant to the conditions of IOPF. For a wide range of DZIB conditions, we evaluate the gap-opening masses of planets in these disks that are expected to lead to the truncation of pebble accretion onto the forming planet. We then consider the evolution of dust and pebbles in the disk, estimating that pebbles typically grow to sizes of a few centimeters during their radial drift from several tens of astronomical units to the inner, ≲1 au scale disk. A large fraction of the accretion flux of solids is expected to be in such pebbles. This allows us to estimate the timescales for individual planet formation and the entire planetary system formation in the IOPF scenario. We find that to produce realistic STIPs within reasonable timescales similar to disk lifetimes requires disk accretion rates of ∼10‑9 M ⊙ yr‑1 and relatively low viscosity conditions in the DZIB region, i.e., a Shakura–Sunyaev parameter of α ∼ 10‑4.

PCF File Format.

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

Thoreson, Gregory G

PCF files are binary files designed to contain gamma spectra and neutron count rates from radiation sensors. It is the native format for the GAmma Detector Response and Analysis Software (GADRAS) package [1]. It can contain multiple spectra and information about each spectrum such as energy calibration. This document outlines the format of the file that would allow one to write a computer program to parse and write such files.

Formation Flying for Distributed InSAR

NASA Technical Reports Server (NTRS)

Scharf, Daniel P.; Murray, Emmanuell A.; Ploen, Scott R.; Gromov, Konstantin G.; Chen, Curtis W.

2006-01-01

We consider two spacecraft flying in formation to create interferometric synthetic aperture radar (InSAR). Several candidate orbits for such in InSar formation have been previously determined based on radar performance and Keplerian orbital dynamics. However, with out active control, disturbance-induced drift can degrade radar performance and (in the worst case) cause a collision. This study evaluates the feasibility of operating the InSAR spacecraft as a formation, that is, with inner-spacecraft sensing and control. We describe the candidate InSAR orbits, design formation guidance and control architectures and algorithms, and report the (Delta)(nu) and control acceleration requirements for the candidate orbits for several tracking performance levels. As part of determining formation requirements, a formation guidance algorithm called Command Virtual Structure is introduced that can reduce the (Delta)(nu) requirements compared to standard Leader/Follower formation approaches.

Perceptions and practices of U.S. dental schools regarding curriculum integrated format and traditional format licensure exams.

PubMed

Desai, Shamik; Allareddy, Veerasathpurush; Donoff, R Bruce; Howell, T Howard; Karimbux, Nadeem Y

2013-08-01

The dental licensure exam in the United States has evolved over the past ten years, and two formats-the traditional format and curriculum integrated format-are now available for students to satisfy licensure requirements. The objective of this study was to examine the differences and relative merits of the two formats. A twenty-five-question survey was distributed to the fifty-seven U.S. dental schools at the time. The survey included both quantitative and discrete variables and followed a strategic sequential order. The first set of questions sought to determine what type of board preparatory/mock exam each dental school offered, and the next set of questions asked which licensure exam each school formally offered. The final questions were qualitative in nature and aimed to determine the school representatives' opinions about the curriculum integrated format versus traditional format. Of the fifty-seven schools contacted, thirty-seven agreed to participate (response rate=64.9 percent). Fourteen schools reported that they administer the traditional format only and twelve administer the curriculum integrated format only, while eleven offer both. Thirty-two schools offered mock board exams to their graduating students, and twenty-four of those said their mock exams were identical in format to the actual qualifying clinical exams offered at their institution. The respondents reported no significant advantage to preparing for the curriculum integrated format examination as compared to the traditional format examination with regards to number of clock hours taken from regular curriculum time. In reporting on this study, this article provides an overview of the relative advantages and disadvantages of the two examination formats used for the dental licensure process in the United States.

What Is Formation? A Conceptual Discussion

ERIC Educational Resources Information Center

Sutphen, Molly; de Lange, Thomas

2015-01-01

This paper addresses the principles and connotations of the term "formation." In our discussion of formation, we draw on different disciplines in order to widen and deepen our understanding of the concept of formation. We also mirror the formation concept against comparable terms and draw on studies in which it has been applied in…

View of Argentina-Paraguay border area of South America

NASA Image and Video Library

1973-08-30

SL3-33-167 (July-September 1973) --- A vertical view of the Argentina-Paraguay border area of South America as photographed from Earth orbit by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility Experiment aboard the Skylab space station. This picture was taken with type 2443 infrared color film. The Parana River flows from east to west across the picture. This part of the Rio Parana is located between the towns of Posadas, Argentina, and Resistencia, Argentina. The major body of water in the large swamp area is Laguna Ibera. Note the several fires burning in this area. The largest land mass (Argentina) is south of the river. Paraguay is north of the river. Isla Apipe Grande is near the center of the photograph. The S190-A experiment is part of the Skylab Earth Resources Experiments Package. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior?s Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. Photo credit: NASA

Spatially-resolved star formation histories of CALIFA galaxies. Implications for galaxy formation

NASA Astrophysics Data System (ADS)

González Delgado, R. M.; Pérez, E.; Cid Fernandes, R.; García-Benito, R.; López Fernández, R.; Vale Asari, N.; Cortijo-Ferrero, C.; de Amorim, A. L.; Lacerda, E. A. D.; Sánchez, S. F.; Lehnert, M. D.; Walcher, C. J.

2017-11-01

This paper presents the spatially resolved star formation history (SFH) of nearby galaxies with the aim of furthering our understanding of the different processes involved in the formation and evolution of galaxies. To this end, we apply the fossil record method of stellar population synthesis to a rich and diverse data set of 436 galaxies observed with integral field spectroscopy in the CALIFA survey. The sample covers a wide range of Hubble types, with stellar masses ranging from M⋆ 109 to 7 × 1011 M⊙. Spectral synthesis techniques are applied to the datacubes to retrieve the spatially resolved time evolution of the star formation rate (SFR), its intensity (ΣSFR), and other descriptors of the 2D SFH in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd) and five bins of stellar mass. Our main results are that (a) galaxies form very fast independently of their current stellar mass, with the peak of star formation at high redshift (z > 2). Subsequent star formation is driven by M⋆ and morphology, with less massive and later type spirals showing more prolonged periods of star formation. (b) At any epoch in the past, the SFR is proportional to M⋆, with most massive galaxies having the highest absolute (but lowest specific) SFRs. (c) While today, the ΣSFR is similar for all spirals and significantly lower in early-type galaxies (ETG), in the past, the ΣSFR scales well with morphology. The central regions of today's ETGs are where the ΣSFR reached the highest values (> 103 M⊙ Gyr-1 pc-2), similar to those measured in high-redshift star-forming galaxies. (d) The evolution of ΣSFR in Sbc systems matches that of models for Milky Way-like galaxies, suggesting that the formation of a thick disk may be a common phase in spirals at early epochs. (e) The SFR and ΣSFR in outer regions of E and S0 galaxies show that they have undergone an extended phase of growth in mass between z = 2 and 0.4. The mass assembled in this phase is in agreement with

Transition to the vgosDb Format

NASA Astrophysics Data System (ADS)

Bolotin, Sergei; Baver, Karen; Gipson, John; Gordon, David; MacMillan, Daniel

2016-12-01

The IVS Working Group 4 developed a new format to store and exchange data obtained from geodetic VLBI observations. The new data format, vgosDb, will replace existing Mark III databases this year. At GSFC we developed utilities that implement the vgosDb format and will be used routinely to convert correlator output to the new data storage format.

Physics of primordial star formation

NASA Astrophysics Data System (ADS)

Yoshida, Naoki

2012-09-01

The study of primordial star formation has a history of nearly sixty years. It is generally thought that primordial stars are one of the key elements in a broad range of topics in astronomy and cosmology, from Galactic chemical evolution to the formation of super-massive blackholes. We review recent progress in the theory of primordial star formation. The standard theory of cosmic structure formation posits that the present-day rich structure of the Universe developed through gravitational amplification of tiny matter density fluctuations left over from the Big Bang. It has become possible to study primordial star formation rigorously within the framework of the standard cosmological model. We first lay out the key physical processes in a primordial gas. Then, we introduce recent developments in computer simulations. Finally, we discuss prospects for future observations of the first generation of stars.

A Format for Phylogenetic Placements

PubMed Central

Matsen, Frederick A.; Hoffman, Noah G.; Gallagher, Aaron; Stamatakis, Alexandros

2012-01-01

We have developed a unified format for phylogenetic placements, that is, mappings of environmental sequence data (e.g., short reads) into a phylogenetic tree. We are motivated to do so by the growing number of tools for computing and post-processing phylogenetic placements, and the lack of an established standard for storing them. The format is lightweight, versatile, extensible, and is based on the JSON format, which can be parsed by most modern programming languages. Our format is already implemented in several tools for computing and post-processing parsimony- and likelihood-based phylogenetic placements and has worked well in practice. We believe that establishing a standard format for analyzing read placements at this early stage will lead to a more efficient development of powerful and portable post-analysis tools for the growing applications of phylogenetic placement. PMID:22383988

A format for phylogenetic placements.

PubMed

Matsen, Frederick A; Hoffman, Noah G; Gallagher, Aaron; Stamatakis, Alexandros

2012-01-01

We have developed a unified format for phylogenetic placements, that is, mappings of environmental sequence data (e.g., short reads) into a phylogenetic tree. We are motivated to do so by the growing number of tools for computing and post-processing phylogenetic placements, and the lack of an established standard for storing them. The format is lightweight, versatile, extensible, and is based on the JSON format, which can be parsed by most modern programming languages. Our format is already implemented in several tools for computing and post-processing parsimony- and likelihood-based phylogenetic placements and has worked well in practice. We believe that establishing a standard format for analyzing read placements at this early stage will lead to a more efficient development of powerful and portable post-analysis tools for the growing applications of phylogenetic placement.

Display formats manual

NASA Technical Reports Server (NTRS)

Runnels, R. L.

1973-01-01

The standards and procedures for the generation of operational display formats to be used in the Mission Control Center (MCC) display control system are presented. The required effort, forms, and fundamentals for the design, specifications, and production of display formats are identified. The principles of display design and system constraints controlling the creation of optimum operational displays for mission control are explained. The basic two types of MCC display systems for presenting information are described.

PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

PubMed Central

Price, Winston H.

1949-01-01

1. A non-dialyzable fraction from fresh bakers' yeast stimulates the formation of S. muscae virus in cells in synthetic medium in the log phase of multiplication. 2. A similar fraction was not found in calf thymus, pancreas, or liver. 3. The active substance in this fraction has been partially purified. 4. This substance is taken up by the cells. In the absence of virus the added substance is metabolized to a form no longer available for virus formation. 5. A purified yeast fraction, which stimulates adaptive enzyme formation in yeast, has been found to stimulate virus formation in the S. muscae system. 6. The similarities between the yeast fraction that stimulates adaptive enzyme formation and the yeast fraction that stimulates virus formation are discussed. PMID:18123312

A possible formation scenario for dwarf spheroidal galaxies - III. Adding star formation histories to the fiducial model

NASA Astrophysics Data System (ADS)

Alarcón Jara, A. G.; Fellhauer, M.; Matus Carrillo, D. R.; Assmann, P.; Urrutia Zapata, F.; Hazeldine, J.; Aravena, C. A.

2018-02-01

Dwarf spheroidal galaxies are regarded as the basic building blocks in the formation of larger galaxies and are the most dark matter dominated systems in the Universe, known so far. There are several models that attempt to explain their formation and evolution, but they have problems modelling the formation of isolated dwarf spheroidal galaxies. Here, we will explain a possible formation scenario in which star clusters form inside the dark matter halo of a dwarf spheroidal galaxy. These star clusters suffer from low star formation efficiency and dissolve while orbiting inside the dark matter halo. Thereby, they build the faint luminous components that we observe in dwarf spheroidal galaxies. In this paper, we study this model by adding different star formation histories to the simulations and compare the results with our previous work and observational data to show that we can explain the formation of dwarf spheroidal galaxies.

Formate Dehydrogenase from Clostridium acidiurici

PubMed Central

Kearny, James J.; Sagers, Richard D.

1972-01-01

Partial purification of formate dehydrogenase from Clostridium acidiurici has been accomplished, and some properties of the enzyme have been determined. The molecular weight of the protein is at least 200,000 daltons. The enzyme showed marked instability to freezing and thawing and was inhibited strongly by oxygen and by light. Such inhibition was not reversed by incubation in the presence of thiol compounds. Cyanide inhibited the enzyme 90% at 0.1 mm concentrations, but ethylenediaminetetraacetate produced only slight inhibition at concentrations as high as 50 mm. The purified enzyme showed no ferredoxin activity in the Clostridium pasteurianum clastic system during pyruvate oxidation. Crude preparations of the enzyme could be coupled through ferredoxin to the reduction of nicotinamide adenine dinucleotide during formate oxidation, but the purified enzyme could not catalyze the reduction of pyridine nucleotides by formate in the presence of ferredoxin. Formate oxidation with the purified enzyme was readily coupled to benzyl viologen reduction, in which case ferredoxin was not required. An exchange between formate and bicarbonate was catalyzed by both crude and purified preparations of the enzyme, but the net synthesis of formate from CO2 was not accomplished. PMID:4333376

Star formation inside a galactic outflow.

PubMed

Maiolino, R; Russell, H R; Fabian, A C; Carniani, S; Gallagher, R; Cazzoli, S; Arribas, S; Belfiore, F; Bellocchi, E; Colina, L; Cresci, G; Ishibashi, W; Marconi, A; Mannucci, F; Oliva, E; Sturm, E

2017-04-13

Recent observations have revealed massive galactic molecular outflows that may have the physical conditions (high gas densities) required to form stars. Indeed, several recent models predict that such massive outflows may ignite star formation within the outflow itself. This star-formation mode, in which stars form with high radial velocities, could contribute to the morphological evolution of galaxies, to the evolution in size and velocity dispersion of the spheroidal component of galaxies, and would contribute to the population of high-velocity stars, which could even escape the galaxy. Such star formation could provide in situ chemical enrichment of the circumgalactic and intergalactic medium (through supernova explosions of young stars on large orbits), and some models also predict it to contribute substantially to the star-formation rate observed in distant galaxies. Although there exists observational evidence for star formation triggered by outflows or jets into their host galaxy, as a consequence of gas compression, evidence for star formation occurring within galactic outflows is still missing. Here we report spectroscopic observations that unambiguously reveal star formation occurring in a galactic outflow at a redshift of 0.0448. The inferred star-formation rate in the outflow is larger than 15 solar masses per year. Star formation may also be occurring in other galactic outflows, but may have been missed by previous observations owing to the lack of adequate diagnostics.

Freeze/Thaw-Induced Embolism: Probability of Critical Bubble Formation Depends on Speed of Ice Formation

DOE PAGES

Sevanto, Sanna; Holbrook, N. Michele; Ball, Marilyn C.

2012-06-06

Bubble formation in the conduits of woody plants sets a challenge for uninterrupted water transportation from the soil up to the canopy. Freezing and thawing of stems has been shown to increase the number of air-filled (embolized) conduits, especially in trees with large conduit diameters. Despite numerous experimental studies, the mechanisms leading to bubble formation during freezing have not been addressed theoretically. We used classical nucleation theory and fluid mechanics to show which mechanisms are most likely to be responsible for bubble formation during freezing and what parameters determine the likelihood of the process. Our results confirm the common assumptionmore » that bubble formation during freezing is most likely due to gas segregation by ice. If xylem conduit walls are not permeable to the salts expelled by ice during the freezing process, osmotic pressures high enough for air seeding could be created. The build-up rate of segregated solutes in front of the ice-water interface depends equally on conduit diameter and freezing velocity. Therefore, bubble formation probability depends on these variables. The dependence of bubble formation probability on freezing velocity means that the experimental results obtained for cavitation threshold conduit diameters during freeze/thaw cycles depend on the experimental setup; namely sample size and cooling rate. The velocity dependence also suggests that to avoid bubble formation during freezing trees should have narrow conduits where freezing is likely to be fast (e.g., branches or outermost layer of the xylem). Avoidance of bubble formation during freezing could thus be one piece of the explanation why xylem conduit size of temperate and boreal zone trees varies quite systematically.« less

Freeze/Thaw-induced embolism: probability of critical bubble formation depends on speed of ice formation.

PubMed

Sevanto, Sanna; Holbrook, N Michele; Ball, Marilyn C

2012-01-01

Bubble formation in the conduits of woody plants sets a challenge for uninterrupted water transportation from the soil up to the canopy. Freezing and thawing of stems has been shown to increase the number of air-filled (embolized) conduits, especially in trees with large conduit diameters. Despite numerous experimental studies, the mechanisms leading to bubble formation during freezing have not been addressed theoretically. We used classical nucleation theory and fluid mechanics to show which mechanisms are most likely to be responsible for bubble formation during freezing and what parameters determine the likelihood of the process. Our results confirm the common assumption that bubble formation during freezing is most likely due to gas segregation by ice. If xylem conduit walls are not permeable to the salts expelled by ice during the freezing process, osmotic pressures high enough for air seeding could be created. The build-up rate of segregated solutes in front of the ice-water interface depends equally on conduit diameter and freezing velocity. Therefore, bubble formation probability depends on these variables. The dependence of bubble formation probability on freezing velocity means that the experimental results obtained for cavitation threshold conduit diameters during freeze/thaw cycles depend on the experimental setup; namely sample size and cooling rate. The velocity dependence also suggests that to avoid bubble formation during freezing trees should have narrow conduits where freezing is likely to be fast (e.g., branches or outermost layer of the xylem). Avoidance of bubble formation during freezing could thus be one piece of the explanation why xylem conduit size of temperate and boreal zone trees varies quite systematically.

Struvite scale formation and control.

PubMed

Parsons, S A; Doyle, J D

2004-01-01

Struvite scale formation is a major operational issue at both conventional and biological nutrient removal wastewater treatment plants. Factors affecting the formation of struvite scales were investigated including supersaturation, pH and pipe material and roughness. A range of control methods have been investigated including low fouling materials, pH control, inhibitor and chemical dosing. Control methods exist to reduce scale formation although each has its advantages and disadvantages.

Anaerobic Formate and Hydrogen Metabolism.

PubMed

Pinske, Constanze; Sawers, R Gary

2016-10-01

Numerous recent developments in the biochemistry, molecular biology, and physiology of formate and H2 metabolism and of the [NiFe]-hydrogenase (Hyd) cofactor biosynthetic machinery are highlighted. Formate export and import by the aquaporin-like pentameric formate channel FocA is governed by interaction with pyruvate formate-lyase, the enzyme that generates formate. Formate is disproportionated by the reversible formate hydrogenlyase (FHL) complex, which has been isolated, allowing biochemical dissection of evolutionary parallels with complex I of the respiratory chain. A recently identified sulfido-ligand attached to Mo in the active site of formate dehydrogenases led to the proposal of a modified catalytic mechanism. Structural analysis of the homologous, H2-oxidizing Hyd-1 and Hyd-5 identified a novel proximal [4Fe-3S] cluster in the small subunit involved in conferring oxygen tolerance to the enzymes. Synthesis of Salmonella Typhimurium Hyd-5 occurs aerobically, which is novel for an enterobacterial Hyd. The O2-sensitive Hyd-2 enzyme has been shown to be reversible: it presumably acts as a conformational proton pump in the H2-oxidizing mode and is capable of coupling reverse electron transport to drive H2 release. The structural characterization of all the Hyp maturation proteins has given new impulse to studies on the biosynthesis of the Fe(CN)2CO moiety of the [NiFe] cofactor. It is synthesized on a Hyp-scaffold complex, mainly comprising HypC and HypD, before insertion into the apo-large subunit. Finally, clear evidence now exists indicating that Escherichia coli can mature Hyd enzymes differentially, depending on metal ion availability and the prevailing metabolic state. Notably, Hyd-3 of the FHL complex takes precedence over the H2-oxidizing enzymes.

Investigating the Formation Mechanisms and Inorganic Precursors of Formate and Acetate in Lost City Hydrothermal Fluids

NASA Astrophysics Data System (ADS)

Lang, S. Q.; Bernasconi, S. M.; Früh-Green, G.

2010-12-01

Fluids from the Lost City Hydrothermal Field are rich in hydrogen and methane, with high pHs (9 - 11), as a result of serpentinization reactions at moderate temperatures of approximately 120-200°C. It has been predicted that organic carbon compounds would form abiologically under these chemical and thermal conditions from inorganic precursors, in the form of hydrocarbons and organic acids. Previous work has demonstrated the presence of high concentrations of both formate and acetate in the Lost City fluids [Lang et al., 2010, GCA]. Formate is the second most prevalent carbon species in the fluids and may provide local microbial communities with a necessary carbon source in the face of low dissolved inorganic carbon concentrations. The goals of this study are to constrain the formation mechanisms of these organic acids (abiotic vs. biotic) and to identify their inorganic precursors. Formate and acetate were isolated from multiple fluid samples by preparative high-performance liquid chromatography for isotopic analysis. The δ13C of formate is similar to that of Lost City methane, and consistent with an abiological origin. The isotopic signature of acetate is significantly different from these values, and may be indicative of a biological source. Radiocarbon measurements of the isolated formate are in progress and should allow us to determine if the precursor carbon is derived from a mantle or deep-seawater source. Alkaline hydrothermal systems have been proposed as potential sites to the origin of life and formate has been proposed as a critical intermediate towards the kinds of reduced carbon species found in biochemistry. Evidence of an abiological formation mechanism of formate at Lost City may significantly further our understanding of prebiotic chemistry.

Mesoarchean Banded Iron Formation sequences in Dixon Island-Cleaverville Formation, Pilbara Australia: Oxygenic signal from DXCL project

NASA Astrophysics Data System (ADS)

Kiyokawa, S.; Ito, T.; Ikehara, M.; Yamaguchi, K. E.; Naraoka, H.; Onoue, T.; Horie, K.; Sakamoto, R.; Aihara, Y.; Miki, T.

2013-12-01

The 3.2-3.1 Ga Dixon island-Cleaverville formations are well-preserved Banded Iron Formation (BIF) within hydrothermal oceanic sequence at oceanic island arc setting (Kiyokawa et al., 2002, 2006, 2012). The stratigraphy of the Dixon Island (3195+15Ma) -Cleaverville (3108+13Ma) formations shows the well preserved environmental condition at the Mesoarchean ocean floor. The stratigraphy of these formations are formed about volcano-sedimentary sequences with hydrothermal chert, black shale and banded iron formation to the top. Based on the scientific drilling of DXCL project at 2007 and 2011, detail lithology between BIF sequence was clearly understood. Four drilling holes had been done at coastal sites; the Dixon Island Formation is DX site (100m) and the Cleaverville Formation is CL2 (40m), CL1 (60m) and CL3 (200m) sites and from stratigraphic bottom to top. Coarsening and thickening upward black shale-BIF sequences are well preserved of the stratigraphy form the core samples. The Dixon Island Formation consists komatiite-rhyolite sequences with many hydrothermal veins and very fine laminated cherty rocks above them. The Cleaverville Formation contains black shale, fragments-bearing pyroclastic beds, white chert, greenish shale and BIF. The CL3 core, which drilled through BIF, shows siderite-chert beds above black shale identified before magnetite lamination bed. U-Pb SHRIMP data of the tuff in lower Dixon Island Formation is 3195+15 Ma and the pyroclastic sequence below the Cleaverville BIF is 3108+13 Ma. Sedimentation rate of these sequence is 2-8 cm/ 1000year. The hole section of the organic carbon rich black shales below BIF are similar amount of organic content and 13C isotope (around -30per mill). There are very weak sulfur MIF signal (less 0.2%) in these black shale sequence. Our result show that thick organic rich sediments may be triggered to form iron rich siderite and magnetite iron beds. The stratigraphy in this sequence quite resemble to other Iron

Observsational Planet Formation

NASA Astrophysics Data System (ADS)

Dong, Ruobing; Zhu, Zhaohuan; Fung, Jeffrey

2017-06-01

Planets form in gaseous protoplanetary disks surrounding newborn stars. As such, the most direct way to learn how they form from observations, is to directly watch them forming in disks. In the past, this was very difficult due to a lack of observational capabilities; as such, planet formation was largely a subject of pure theoretical astrophysics. Now, thanks to a fleet of new instruments with unprecedented resolving power that have come online recently, we have just started to unveil features in resolve images of protoplanetary disks, such as gaps and spiral arms, that are most likely associated with embedded (unseen) planets. By comparing observations with theoretical models of planet-disk interactions, the masses and orbits of these still forming planets may be constrained. Such planets may help us to directly test various planet formation models. This marks the onset of a new field — observational planet formation. I will introduce the current status of this field.

Treating tar sands formations with karsted zones

DOEpatents

Vinegar, Harold J.; Karanikas, John Michael

2010-03-09

Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

Planet Formation

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.; Young, Richard E. (Technical Monitor)

1997-01-01

Modern theories of star and planet formation, which are based upon observations of the Solar System and of young stars and their environments, predict that most single stars should have rocky planets in orbit about them; the frequency of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth like terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Models for the formation of the giant planets found in recent radial velocity searches are discussed.

Diet History Questionnaire II: Size Formats

Cancer.gov

Two serving size formats are used on the NCI versions of the DHQ as shown below. Format 1 is used for nearly all serving size questions. Format 2 is used only in special cases, where 'never' is allowed as a response.

The dynamics of latifundia formation.

PubMed

Chaves, Luis Fernando

2013-01-01

Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia.

An Adaptable Seismic Data Format

NASA Astrophysics Data System (ADS)

Krischer, Lion; Smith, James; Lei, Wenjie; Lefebvre, Matthieu; Ruan, Youyi; de Andrade, Elliott Sales; Podhorszki, Norbert; Bozdağ, Ebru; Tromp, Jeroen

2016-11-01

We present ASDF, the Adaptable Seismic Data Format, a modern and practical data format for all branches of seismology and beyond. The growing volume of freely available data coupled with ever expanding computational power opens avenues to tackle larger and more complex problems. Current bottlenecks include inefficient resource usage and insufficient data organization. Properly scaling a problem requires the resolution of both these challenges, and existing data formats are no longer up to the task. ASDF stores any number of synthetic, processed or unaltered waveforms in a single file. A key improvement compared to existing formats is the inclusion of comprehensive meta information, such as event or station information, in the same file. Additionally, it is also usable for any non-waveform data, for example, cross-correlations, adjoint sources or receiver functions. Last but not least, full provenance information can be stored alongside each item of data, thereby enhancing reproducibility and accountability. Any data set in our proposed format is self-describing and can be readily exchanged with others, facilitating collaboration. The utilization of the HDF5 container format grants efficient and parallel I/O operations, integrated compression algorithms and check sums to guard against data corruption. To not reinvent the wheel and to build upon past developments, we use existing standards like QuakeML, StationXML, W3C PROV and HDF5 wherever feasible. Usability and tool support are crucial for any new format to gain acceptance. We developed mature C/Fortran and Python based APIs coupling ASDF to the widely used SPECFEM3D_GLOBE and ObsPy toolkits.

An Overview of the Formation and Attitude Control System for the Terrestrial Planet Finder Formation Flying Interferometer

NASA Technical Reports Server (NTRS)

Scharf, Daniel P.; Hadaegh, Fred Y.; Rahman, Zahidul H.; Shields, Joel F.; Singh, Gurkipal; Wette, Matthew R.

2004-01-01

The Terrestrial Planet Finder formation flying Interferometer (TPF-I) will be a five-spacecraft, precision formation operating near the second Sun-Earth Lagrange point. As part of technology development for TPF-I, a formation and attitude control system (FACS) is being developed that achieves the precision and functionality needed for the TPF-I formation and that will be demonstrated in a distributed, real-time simulation environment. In this paper we present an overview of FACS and discuss in detail its formation estimation, guidance and control architectures and algorithms. Since FACS is currently being integrated into a high-fidelity simulation environment, component simulations demonstrating algorithm performance are presented.

An Overview of the Formation and Attitude Control System for the Terrestrial Planet Finder Formation Flying Interferometer

NASA Technical Reports Server (NTRS)

Scharf, Daniel P.; Hadaegh, Fred Y.; Rahman, Zahidul H.; Shields, Joel F.; Singh, Gurkipal

2004-01-01

The Terrestrial Planet Finder formation flying Interferometer (TPF-I) will be a five-spacecraft, precision formation operating near a Sun-Earth Lagrange point. As part of technology development for TPF-I, a formation and attitude control system (FACS) is being developed that achieves the precision and functionality associated with the TPF-I formation. This FACS will be demonstrated in a distributed, real-time simulation environment. In this paper we present an overview of the FACS and discuss in detail its constituent formation estimation, guidance and control architectures and algorithms. Since the FACS is currently being integrated into a high-fidelity simulation environment, component simulations demonstrating algorithm performance are presented.

Medusae Fossae Formation

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 10 April 2002) The Science This THEMIS visible image was acquired near 7o S, 172o W (188o E) and shows a remarkable martian geologic deposit known as the Medusae Fossae Formation. This Formation, seen here as the raised plateau in the upper two-thirds of the image, is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region the deposit has been heavily eroded by the wind to produce a series of linear ridges called yardangs. These parallel ridges point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to sculpt the dry landscape of Mars. The Medusae Fossae Formation has been completely stripped from the surface in the lower third of the image, revealing a harder layer below that is more resistant to wind erosion. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Several ancient craters that were once completely buried by this deposit are being exposed, or exhumed, as the overlying Medusae Formation is removed. Very few impact craters are visible on this Formation, indicating that the surface seen today is relatively young, and that the processes of erosion are likely to be actively occurring. The Story Medusa of Greek mythology fame, the name-giver to this region, had snaky locks of hair that could turn a person to stone. Wild and unruly, this monster of the underworld could certainly wreak havoc on the world of the human imagination. As scary as she was, Medusa would have no advantage over the fierce, masterful winds blowing across Mars, which once carved the streaky, terrain at the top of this image. Wild and whipping, these winds have slowly eroded away the 'topsoil,' revealing ancient craters and other surface features they once covered. The loosely cemented particles of this 'topsoil' are likely made up of dust

Optimal Configurations for Rotating Spacecraft Formations

NASA Technical Reports Server (NTRS)

Hughes, Steven P.; Hall, Christopher D.

2000-01-01

In this paper a new class of formations that maintain a constant shape as viewed from the Earth is introduced. An algorithm is developed to place n spacecraft in a constant shape formation spaced equally in time using the classical orbital elements. To first order, the dimensions of the formation are shown to be simple functions of orbit eccentricity and inclination. The performance of the formation is investigated over a Keplerian orbit using a performance measure based on a weighted average of the angular separations between spacecraft in formation. Analytic approximations are developed that yield optimum configurations for different values of n. The analytic approximations are shown to be in excellent agreement with the exact solutions.

Ice Formation on Wings

NASA Technical Reports Server (NTRS)

Ritz, L

1939-01-01

This report makes use of the results obtained in the Gottingen ice tunnel in which the atmospheric conditions are simulated and the process of ice formation photographed. The effect of ice formation is threefold: 1) added weight to the airplane; 2) a change in the lift and drag forces; 3) a change in the stability characteristics.

Formative Assessment: Policy, Perspectives and Practice

ERIC Educational Resources Information Center

Clark, Ian

2011-01-01

Proponents of formative assessment (FA) assert that students develop a deeper understanding of their learning when the essential components of formative feedback and cultural responsiveness are effectively incorporated as central features of the formative assessment process. Even with growing international agreement among the research community…

Successful Student Writing through Formative Assessment

ERIC Educational Resources Information Center

Tuttle, Harry Grover

2010-01-01

Use formative assessment to dramatically improve your students' writing. In "Successful Student Writing Through Formative Assessment", educator and international speaker Harry G. Tuttle shows you how to guide middle and high school students through the prewriting, writing, and revision processes using formative assessment techniques that work.…

FRS Geospatial Return File Format

EPA Pesticide Factsheets

The Geospatial Return File Format describes format that needs to be used to submit latitude and longitude coordinates for use in Envirofacts mapping applications. These coordinates are stored in the Geospatail Reference Tables.

The Dynamics of Latifundia Formation

PubMed Central

Chaves, Luis Fernando

2013-01-01

Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia. PMID:24376597

Planet Formation

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.; DeVincenzi, Donald L. (Technical Monitor)

1998-01-01

An overview of current theories of star and planet formation is presented. These models are based upon observations of the Solar System and of young stars and their environments. They predict that rocky planets should form around most single stars, although it is possible that in some cases such planets are lost to orbital decay within the protoplanetary disk. The frequency of formation of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth like terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates.

Galaxy formation

PubMed Central

Peebles, P. J. E.

1998-01-01

It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z ∼ 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation. PMID:9419326

BACTERIOPHAGE FORMATION WITHOUT BACTERIAL GROWTH

PubMed Central

Price, Winston H.

1947-01-01

1. Iodoacetate, fluoride, and azide have been found to prevent the formation of phage and to inhibit the synthesis of ATP by Staphylococcus muscae. It is suggested that energy-rich phosphate is needed for the synthesis of phage. 2. Gramicidin prevented the formation of phage. 3. No differences were found between normal bacteria and phage-infected bacteria in the inorganic phosphate, adenosinetriphosphate, ribonucleic acid, and desoxyribonucleic acid content of the cells. 4. The mechanism of phage formation is discussed. PMID:18896936

7 CFR 1755.407 - Data formats.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 11 2013-01-01 2013-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test data...

7 CFR 1755.407 - Data formats.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 11 2012-01-01 2012-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test data...

7 CFR 1755.407 - Data formats.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 11 2014-01-01 2014-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test data...

7 CFR 1755.407 - Data formats.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test data...

7 CFR 1755.407 - Data formats.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 11 2011-01-01 2011-01-01 false Data formats. 1755.407 Section 1755.407 Agriculture... TELECOMMUNICATIONS POLICIES ON SPECIFICATIONS, ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.407 Data formats. The following suggested formats listed in this section may be used for recording the test data...

Treating tar sands formations with dolomite

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

Vinegar, Harold J.; Karanikas, John Michael

A method for treating a karsted formation containing heavy hydrocarbons and dolomite includes providing heat to at least part of one or more karsted layers in the formation from one or more heaters located in the karsted layers. A temperature in at least one of the karsted layers is allowed to reach a decomposition temperature of dolomite in the formation. The dolomite is allowed to decompose and at least some hydrocarbons are produced from at least one of the karsted layers of the formation.

Star Formation History In Merging Galaxies

NASA Astrophysics Data System (ADS)

Chien, Li-Hsin

2009-01-01

Interacting and merging galaxies are believed to play an important role in many aspects of galactic evolution. Their violent interactions can trigger starbursts, which lead to formation of young globular clusters. Therefore the ages of these young globular clusters can be interpreted to yield the timing of interaction-triggered events, and thus provide a key to reconstruct the star formation history in merging galaxies. The link between galaxy interaction and star formation is well established, but the triggers of star formation in interacting galaxies are still not understood. To date there are two competing formulas that describe the star formation mechanism--density-dependent and shock-induced rules. Numerical models implementing the two rules predict significantly different star formation histories in merging galaxies. My dissertation combines these two distinct areas of astrophysics, stellar evolution and galactic dynamics, to investigate the star formation history in galaxies at various merging stages. Begin with NGC 4676 as an example, I will briefly describe its model and illustrate the idea of using the ages of clusters to constrain the modeling. The ages of the clusters are derived from spectra that were taken with multi-object spectroscopy on Keck. Using NGC 7252 as a second example, I will present a state of the art dynamical model which predicts NGC7252's star formation history and other properties. I will then show a detailed comparison and analysis between the clusters and the modeling. In the end, I will address this important link as the key to answer the fundamental question of my thesis: what is the trigger of star formation in merging galaxies?

The NeXus data format.

PubMed

Könnecke, Mark; Akeroyd, Frederick A; Bernstein, Herbert J; Brewster, Aaron S; Campbell, Stuart I; Clausen, Björn; Cottrell, Stephen; Hoffmann, Jens Uwe; Jemian, Pete R; Männicke, David; Osborn, Raymond; Peterson, Peter F; Richter, Tobias; Suzuki, Jiro; Watts, Benjamin; Wintersberger, Eugen; Wuttke, Joachim

2015-02-01

NeXus is an effort by an international group of scientists to define a common data exchange and archival format for neutron, X-ray and muon experiments. NeXus is built on top of the scientific data format HDF5 and adds domain-specific rules for organizing data within HDF5 files, in addition to a dictionary of well defined domain-specific field names. The NeXus data format has two purposes. First, it defines a format that can serve as a container for all relevant data associated with a beamline. This is a very important use case. Second, it defines standards in the form of application definitions for the exchange of data between applications. NeXus provides structures for raw experimental data as well as for processed data.

The NeXus data format

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

Könnecke, Mark; Akeroyd, Frederick A.; Bernstein, Herbert J.

2015-01-30

NeXus is an effort by an international group of scientists to define a common data exchange and archival format for neutron, X-ray and muon experiments. NeXus is built on top of the scientific data format HDF5 and adds domain-specific rules for organizing data within HDF5 files, in addition to a dictionary of well defined domain-specific field names. The NeXus data format has two purposes. First, it defines a format that can serve as a container for all relevant data associated with a beamline. This is a very important use case. Second, it defines standards in the form of application definitionsmore » for the exchange of data between applications. NeXus provides structures for raw experimental data as well as for processed data.« less

Wood formation in Angiosperms.

PubMed

Déjardin, Annabelle; Laurans, Françoise; Arnaud, Dominique; Breton, Christian; Pilate, Gilles; Leplé, Jean-Charles

2010-04-01

Wood formation is a complex biological process, involving five major developmental steps, including (1) cell division from a secondary meristem called the vascular cambium, (2) cell expansion (cell elongation and radial enlargement), (3) secondary cell wall deposition, (4) programmed cell death, and (5) heartwood formation. Thanks to the development of genomic studies in woody species, as well as genetic engineering, recent progress has been made in the understanding of the molecular mechanisms underlying wood formation. In this review, we will focus on two different aspects, the lignification process and the control of microfibril angle in the cell wall of wood fibres, as they are both key features of wood material properties. Copyright (c) 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Star Formation in Irregular Galaxies.

ERIC Educational Resources Information Center

Hunter, Deidre; Wolff, Sidney

1985-01-01

Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

Tetrahedron Formation Control

NASA Technical Reports Server (NTRS)

Guzman, Jose J.

2003-01-01

Spacecraft flying in tetrahedron formations are excellent instrument platforms for electromagnetic and plasma studies. A minimum of four spacecraft - to establish a volume - is required to study some of the key regions of a planetary magnetic field. The usefulness of the measurements recorded is strongly affected by the tetrahedron orbital evolution. This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include targeting to a fixed tetrahedron orientation, rotating and translating the tetrahedron and/or varying the initial and final times. The number of impulsive maneuvers citn also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the Magnetospheric Multiscale Mission (MMS) to compute preliminary formation control fuel requirements.

Star Formation in low mass galaxies

NASA Astrophysics Data System (ADS)

Mehta, Vihang

2018-01-01

Our current hierarchical view of the universe asserts that the large galaxies we see today grew via mergers of numerous smaller galaxies. As evidenced by recent literature, the collective impact of these low mass galaxies on the universe is more substantial than previously thought. Studying the growth and evolution of these low mass galaxies is critical to our understanding of the universe as a whole. Star formation is one of the most important ongoing processes in galaxies. Forming stars is fundamental to the growth of a galaxy. One of the main goals of my thesis is to analyze the star formation in these low mass galaxies at different redshifts.Using the Hubble UltraViolet Ultra Deep Field (UVUDF), I investigate the star formation in galaxies at the peak of the cosmic star formation history using the ultraviolet (UV) light as a star formation indicator. Particularly, I measure the UV luminosity function (LF) to probe the volume-averaged star formation properties of galaxies at these redshifts. The depth of the UVUDF is ideal for a direct measurement of the faint end slope of the UV LF. This redshift range also provides a unique opportunity to directly compare UV to the "gold standard" of star formation indicators, namely the Hα nebular emission line. A joint analysis of the UV and Hα LFs suggests that, on average, the star formation histories in low mass galaxies (~109 M⊙) are more bursty compared to their higher mass counterparts at these redshifts.Complementary to the analysis of the average star formation properties of the bulk galaxy population, I investigate the details of star formation in some very bursty galaxies at lower redshifts selected from Spitzer Large Area Survey with Hyper-Suprime Cam (SPLASH). Using a broadband color-excess selection technique, I identify a sample of low redshift galaxies with bright nebular emission lines in the Subaru-XMM Deep Field (SXDF) from the SPLASH-SXDF catalog. These galaxies are highly star forming and have

Heating systems for heating subsurface formations

DOEpatents

Nguyen, Scott Vinh [Houston, TX; Vinegar, Harold J [Bellaire, TX

2011-04-26

Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

Agriculture on the Chaco Plain, Paraguay, South America

NASA Technical Reports Server (NTRS)

1990-01-01

This view of extensive agriculture on the Chaco Plain, Paraguay, (22.5S, 60.5W) depicts the fertility of the soils between the Andes Mountains and the Paraguay - Parana Rivers in the northwestern Paraguay. The Gran Chaco Plain is flat landscape built up by sediments. Frontier settlements like Marsical Estigarribia, seen in the image, are dominated by agriculture along the stream courses that abound in the area.

Translations on Latin America, Number 1630

DTIC Science & Technology

1977-04-07

0 ESTADO DE SAO PAULO, 15 Mar 77) 23 - a - [III - LA - 144] CONTENTS (Continued) Page Construction Industry Problems Analyzed Construction...sedimentary basins, especially in Amazonia and in Parana. For these areas it will be necessary to de - termine more attractive conditions in order to increase...Dam, and surfacing construction industry). Jorge Luis de La Rocque, a representative of that union, ex- pressed the hope that "the dialog will start

Formative Constructs Implemented via Common Factors

ERIC Educational Resources Information Center

Treiblmaier, Horst; Bentler, Peter M.; Mair, Patrick

2011-01-01

Recently there has been a renewed interest in formative measurement and its role in properly specified models. Formative measurement models are difficult to identify, and hence to estimate and test. Existing solutions to the identification problem are shown to not adequately represent the formative constructs of interest. We propose a new two-step…

Formative Assessment: Responding to Your Students

ERIC Educational Resources Information Center

Tuttle, Harry Grover

2009-01-01

This "how-to" book on formative assessment is filled with practical suggestions for teachers who want to use formative assessment in their classrooms. With practical strategies, tools, and examples for teachers of all subjects and grade levels, this book shows you how to use formative assessment to promote successful student learning. Topics…

Seismic attributes and advanced computer algorithm to predict formation pore pressure: Qalibah formation of Northwest Saudi Arabia

NASA Astrophysics Data System (ADS)

Nour, Abdoulshakour M.

Oil and gas exploration professionals have long recognized the importance of predicting pore pressure before drilling wells. Pre-drill pore pressure estimation not only helps with drilling wells safely but also aids in the determination of formation fluids migration and seal integrity. With respect to the hydrocarbon reservoirs, the appropriate drilling mud weight is directly related to the estimated pore pressure in the formation. If the mud weight is lower than the formation pressure, a blowout may occur, and conversely, if it is higher than the formation pressure, the formation may suffer irreparable damage due to the invasion of drilling fluids into the formation. A simple definition of pore pressure is the pressure of the pore fluids in excess of the hydrostatic pressure. In this thesis, I investigated the utility of advance computer algorithm called Support Vector Machine (SVM) to learn the pattern of high pore pressure regime, using seismic attributes such as Instantaneous phase, t*Attenuation, Cosine of Phase, Vp/Vs ratio, P-Impedance, Reflection Acoustic Impedance, Dominant frequency and one well attribute (Mud-Weigh) as the learning dataset. I applied this technique to the over pressured Qalibah formation of Northwest Saudi Arabia. The results of my research revealed that in the Qalibah formation of Northwest Saudi Arabia, the pore pressure trend can be predicted using SVM with seismic and well attributes as the learning dataset. I was able to show the pore pressure trend at any given point within the geographical extent of the 3D seismic data from which the seismic attributes were derived. In addition, my results surprisingly showed the subtle variation of pressure within the thick succession of shale units of the Qalibah formation.

Dioxin formation from waste incineration.

PubMed

Shibamoto, Takayuki; Yasuhara, Akio; Katami, Takeo

2007-01-01

There has been great concern about dioxins-polychlorinated dibenzo dioxins (PCDDs), polychlorinated dibenzo furans (PCDFs), and polychlorinated biphenyls (PCBs)-causing contamination in the environment because the adverse effects of these chemicals on human health have been known for many years. Possible dioxin-contamination has received much attention recently not only by environmental scientists but also by the public, because dioxins are known to be formed during the combustion of industrial and domestic wastes and to escape into the environment via exhaust gases from incinerators. Consequently, there is a pressing need to investigate the formation mechanisms or reaction pathways of these chlorinated chemicals to be able to devise ways to reduce their environmental contamination. A well-controlled small-scale incinerator was used for the experiments in the core references of this review. These articles report the investigation of dioxin formation from the combustion of various waste-simulated samples, including different kinds of paper, various kinds of wood, fallen leaves, food samples, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyvinylidene chloride, polyethylene tetraphthalate (PET), and various kinds of plastic products. These samples were also incinerated with inorganic chlorides (NaCl, KCl, CuCI2, MgCl2, MnCl2, FeCl2, CoCl2, fly ash, and seawater) or organic chlorides (PVC, chlordane, and pentachlorophenol) to investigate the role of chlorine content and/or the presence of different metals in dioxin formation. Some samples, such as newspapers, were burned after they were impregnated with NaCl or PVC, as well as being cocombusted with chlorides. The roles of incineration conditions, including chamber temperatures, O2 concentrations, and CO concentrations, in dioxin formation were also investigated. Dioxins (PCDDs, PCDFs, and coplanar-PCBs) formed in the exhaust gases from a controlled small-scale incinerator, where experimental waste

Relative Navigation of Formation-Flying Satellites

NASA Technical Reports Server (NTRS)

Long, Anne; Kelbel, David; Lee, Taesul; Leung, Dominic; Carpenter, J. Russell; Grambling, Cheryl

2002-01-01

This paper compares autonomous relative navigation performance for formations in eccentric, medium and high-altitude Earth orbits using Global Positioning System (GPS) Standard Positioning Service (SPS), crosslink, and celestial object measurements. For close formations, the relative navigation accuracy is highly dependent on the magnitude of the uncorrelated measurement errors. A relative navigation position accuracy of better than 10 centimeters root-mean-square (RMS) can be achieved for medium-altitude formations that can continuously track at least one GPS signal. A relative navigation position accuracy of better than 15 meters RMS can be achieved for high-altitude formations that have sparse tracking of the GPS signals. The addition of crosslink measurements can significantly improve relative navigation accuracy for formations that use sparse GPS tracking or celestial object measurements for absolute navigation.

Formation Flying Control of Multiple Spacecraft

NASA Technical Reports Server (NTRS)

Hadaegh, F. Y.; Lau, Kenneth; Wang, P. K. C.

1997-01-01

The problem of coordination and control of multiple spacecraft (MS) moving in formation is considered. Here, each MS is modeled by a rigid body with fixed center of mass. First, various schemes for generating the desired formation patterns are discussed, Then, explicit control laws for formation-keeping and relative attitude alignment based on nearest neighbor-tracking are derived. The necessary data which must be communicated between the MS to achieve effective control are examined. The time-domain behavior of the feedback-controlled MS formation for typical low-Earth orbits is studied both analytically and via computer simulation. The paper concludes with a discussion of the implementation of the derived control laws, and the integration of the MS formation coordination and control system with a proposed inter-spacecraft communication/computing network.

Gas-Phase Infrared; JCAMP Format

National Institute of Standards and Technology Data Gateway

SRD 35 NIST/EPA Gas-Phase Infrared; JCAMP Format (PC database for purchase)   This data collection contains 5,228 infrared spectra in the JCAMP-DX (Joint Committee for Atomic and Molecular Physical Data "Data Exchange") format.

The NeXus data format

DOE PAGES

Könnecke, Mark; Akeroyd, Frederick A.; Bernstein, Herbert J.; ...

2015-01-30

NeXus is an effort by an international group of scientists to define a common data exchange and archival format for neutron, X-ray and muon experiments. NeXus is built on top of the scientific data format HDF5 and adds domain-specific rules for organizing data within HDF5 files, in addition to a dictionary of well defined domain-specific field names. The NeXus data format has two purposes. First, it defines a format that can serve as a container for all relevant data associated with a beamline. This is a very important use case. Second, it defines standards in the form of application definitionsmore » for the exchange of data between applications. As a result, NeXus provides structures for raw experimental data as well as for processed data.« less

Formation temperatures of thermogenic and biogenic methane

USGS Publications Warehouse

Stolper, D.A.; Lawson, M.; Davis, C.L.; Ferreira, A.A.; Santos Neto, E. V.; Ellis, G.S.; Lewan, M.D.; Martini, Anna M.; Tang, Y.; Schoell, M.; Sessions, A.L.; Eiler, J.M.

2014-01-01

Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a “clumped isotope” technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

48 CFR 307.7103 - Format.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for preparing an AP. The template for the AP is available on the ASFR/OGAPA/DA Internet Web site. (b) OPDIVs may use the prescribed format without modification or use it as a guideline, as long as the format...

21 CFR 186.1756 - Sodium formate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium formate. 186.1756 Section 186.1756 Food and....1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium hydroxide. (b) The ingredient is...

Formation flying benefits based on vortex lattice calculations

NASA Technical Reports Server (NTRS)

Maskew, B.

1977-01-01

A quadrilateral vortex-lattice method was applied to a formation of three wings to calculate force and moment data for use in estimating potential benefits of flying aircraft in formation on extended range missions, and of anticipating the control problems which may exist. The investigation led to two types of formation having virtually the same overall benefits for the formation as a whole, i.e., a V or echelon formation and a double row formation (with two staggered rows of aircraft). These formations have unequal savings on aircraft within the formation, but this allows large longitudinal spacings between aircraft which is preferable to the small spacing required in formations having equal benefits for all aircraft. A reasonable trade-off between a practical formation size and range benefit seems to lie at about three to five aircraft with corresponding maximum potential range increases of about 46 percent to 67 percent. At this time it is not known what fraction of this potential range increase is achievable in practice.

Pictorial Formats. Volume 1. Format Development

DTIC Science & Technology

1982-02-01

inside a threat envelope when the map scale prevents showing the normal cues. 3.1.4 Special Topographic Formats The primary tactical interest in...coverage is in white to prevent confuzing it with the threat’s envelopes. The border between, PMAXI and RMAX2 missile ranges is lined with yellow and... prevent confusion with red-coded emergency action items. 4.3 STORES DISPLAYS: COLOR RASTER Figures 55, 56, 57 and 58 illustrate the color raster

Inviscid Analysis of Extended Formation Flight

NASA Technical Reports Server (NTRS)

Kless, James; Aftosmis, Michael J.; Ning, Simeon Andrew; Nemec, Marian

2012-01-01

Flying airplanes in extended formations, with separation distances of tens of wingspans, significantly improves safety while maintaining most of the fuel savings achieved in close formations. The present study investigates the impact of roll trim and compressibility at fixed lift coefficient on the benefits of extended formation flight. An Euler solver with adjoint-based mesh refinement combined with a wake propagation model is used to analyze a two-body echelon formation at a separation distance of 30 spans. Two geometries are examined: a simple wing and a wing-body geometry. Energy savings, quantified by both formation drag fraction and span efficiency factor, are investigated at subsonic and transonic speeds for a matrix of vortex locations. The results show that at fixed lift and trimmed for roll, the optimal location of vortex impingement is about 10% inboard of the trailing airplane s wing-tip. Interestingly, early results show the variation in drag fraction reduction is small in the neighborhood of the optimal position. Over 90% of energy benefits can be obtained with a 5% variation in transverse and 10% variation in crossflow directions. Early results suggest control surface deflections required to achieve trim reduce the benefits of formation flight by 3-5% at subsonic speeds. The final paper will include transonic effects and trim on extended formation flight drag benefits.

Local Estimators for Spacecraft Formation Flying

NASA Technical Reports Server (NTRS)

Fathpour, Nanaz; Hadaegh, Fred Y.; Mesbahi, Mehran; Nabi, Marzieh

2011-01-01

A formation estimation architecture for formation flying builds upon the local information exchange among multiple local estimators. Spacecraft formation flying involves the coordination of states among multiple spacecraft through relative sensing, inter-spacecraft communication, and control. Most existing formation flying estimation algorithms can only be supported via highly centralized, all-to-all, static relative sensing. New algorithms are needed that are scalable, modular, and robust to variations in the topology and link characteristics of the formation exchange network. These distributed algorithms should rely on a local information-exchange network, relaxing the assumptions on existing algorithms. In this research, it was shown that only local observability is required to design a formation estimator and control law. The approach relies on breaking up the overall information-exchange network into sequence of local subnetworks, and invoking an agreement-type filter to reach consensus among local estimators within each local network. State estimates were obtained by a set of local measurements that were passed through a set of communicating Kalman filters to reach an overall state estimation for the formation. An optimization approach was also presented by means of which diffused estimates over the network can be incorporated in the local estimates obtained by each estimator via local measurements. This approach compares favorably with that obtained by a centralized Kalman filter, which requires complete knowledge of the raw measurement available to each estimator.

Formation Control for the MAXIM Mission

NASA Technical Reports Server (NTRS)

Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

2004-01-01

Over the next twenty years, a wave of change is occurring in the space-based scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today s technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. MAXIM formation flying requirements are on the order of microns, while Stellar Imager mission requirements are on the order of nanometers. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; and (2) the development of linearized equations of relative motion for a formation operating in an n-body gravitational field. Linearized equations of motion provide the ground work for linear formation control designs.

Formation and evolution of dwarf elliptical galaxies - II. Spatially resolved star formation histories

NASA Astrophysics Data System (ADS)

Koleva, Mina; de Rijcke, Sven; Prugniel, Philippe; Zeilinger, Werner W.; Michielsen, Dolf

2009-07-01

We present optical Very Large Telescope spectroscopy of 16 dwarf elliptical galaxies (dEs) comparable in mass to NGC 205, and belonging to the Fornax cluster and to nearby groups of galaxies. Using full-spectrum fitting, we derive radial profiles of the SSP-equivalent ages and metallicities. We make a detailed analysis with ULYSS and STECKMAP of the star formation history in the core of the galaxies and in an aperture of one effective radius. We resolved the history into one to four epochs. The statistical significance of these reconstructions was carefully tested; the two programs give remarkably consistent results. The old stellar population of the dEs, which dominates their mass, is likely coeval with that of massive ellipticals or bulges, but the star formation efficiency is lower. Important intermediate age (1-5 Gyr) populations and frequently tails of star formation until recent times are detected. These histories are reminiscent of their lower mass dwarf spheroidal counterparts of the Local Group. Most galaxies (10/16) show significant metallicity gradients, with metallicity declining by 0.5 dex over one half-light radius on average. These gradients are already present in the old population. The flattened (or discy), rotating objects (6/16) have flat metallicity profiles. This may be consistent with a distinct origin for these galaxies or it may be due to their geometry. The central single stellar population equivalent age varies between 1 and 6 Gyr, with the age slowly increasing with radius in the vast majority of objects. The group and cluster galaxies have similar radial gradients and star formation histories. The strong and old metallicity gradients place important constraints on the possible formation scenarios of dEs. Numerical simulations of the formation of spherical low-mass galaxies reproduce these gradients, but they require a longer time for them to build up. A gentle depletion of the gas, by ram pressure stripping or starvation, could drive the

21 CFR 186.1756 - Sodium formate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium formate. 186.1756 Section 186.1756 Food and... Substances Affirmed as GRAS § 186.1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium...

21 CFR 186.1756 - Sodium formate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium formate. 186.1756 Section 186.1756 Food and... Substances Affirmed as GRAS § 186.1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium...

21 CFR 186.1756 - Sodium formate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium formate. 186.1756 Section 186.1756 Food and... Substances Affirmed as GRAS § 186.1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium...

21 CFR 186.1756 - Sodium formate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium formate. 186.1756 Section 186.1756 Food and... Substances Affirmed as GRAS § 186.1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium...

UFO (UnFold Operator) default data format

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

Kissel, L.; Biggs, F.; Marking, T.R.

The default format for the storage of x,y data for use with the UFO code is described. The format assumes that the data stored in a file is a matrix of values; two columns of this matrix are selected to define a function of the form y = f(x). This format is specifically designed to allow for easy importation of data obtained from other sources, or easy entry of data using a text editor, with a minimum of reformatting. This format is flexible and extensible through the use of inline directives stored in the optional header of the file. Amore » special extension of the format implements encoded data which significantly reduces the storage required as compared wth the unencoded form. UFO supports several extensions to the file specification that implement execute-time operations, such as, transformation of the x and/or y values, selection of specific columns of the matrix for association with the x and y values, input of data directly from other formats (e.g., DAMP and PFF), and a simple type of library-structured file format. Several examples of the use of the format are given.« less

Star Formation in Nearby Galaxies

NASA Astrophysics Data System (ADS)

O'Connell, Robert

2009-07-01

Star formation is a fundamental astrophysical process; it controls phenomena ranging from the evolution of galaxies and nucleosynthesis to the origins of planetary systems and abodes for life. The WFC3, optimized at both UV and IR wavelengths and equipped with an extensive array of narrow-band filters, brings unique capabilities to this area of study. The WFC3 Scientific Oversight Committee {SOC} proposes an integrated program on star formation in the nearby universe which will fully exploit these new abilities. Our targets range from the well-resolved R136 in 30 Dor in the LMC {the nearest super star cluster} and M82 {the nearest starbursting galaxy} to about half a dozen other nearby galaxies that sample a wide range of star-formation rates and environments. Our program consists of broad-band multiwavelength imaging over the entire range from the UV to the near-IR, aimed at studying the ages and metallicities of stellar populations, revealing young stars that are still hidden by dust at optical wavelengths, and showing the integrated properties of star clusters. Narrow-band imaging of the same environments will allow us to measure star-formation rates, gas pressure, chemical abundances, extinction, and shock morphologies. The primary scientific issues to be addressed are: {1} What triggers star formation? {2} How do the properties of star-forming regions vary among different types of galaxies and environments of different gas densities and compositions? {3} How do these different environments affect the history of star formation? {4} Is the stellar initial mass function universal or determined by local conditions?

Requirements for Hirano Body Formation

PubMed Central

Griffin, Paul; Piggott, Cleveland; Maselli, Andrew; Fechheimer, Marcus

2014-01-01

Hirano bodies are paracrystalline F-actin-rich structures associated with diverse conditions, including neurodegeneration and aging. Generation of model Hirano bodies using altered forms of Dictyostelium 34-kDa actin-bundling protein allows studies of their physiological function and mechanism of formation. We describe a novel 34-kDa protein mutant, E60K, with a point mutation within the inhibitory domain of the 34-kDa protein. Expression of E60K in Dictyostelium induces the formation of model Hirano bodies. The E60K protein has activated actin binding and is calcium regulated, unlike other forms of the 34-kDa protein that induce Hirano bodies and that have activated actin binding but lack calcium regulation. Actin filaments in the presence of E60K in vitro show enhanced resistance to disassembly induced by latrunculin B. Actin filaments in model Hirano bodies are also protected from latrunculin-induced depolymerization. We used nocodazole and blebbistatin to probe the role of the microtubules and myosin II, respectively, in the formation of model Hirano bodies. In the presence of these inhibitors, model Hirano bodies can form but are smaller than controls at early times of formation. The ultrastructure of model Hirano bodies did not reveal any major difference in structure and organization in the presence of inhibitors. In summary, these results support the conclusion that formation of model Hirano bodies is promoted by gain-of-function actin filament bundling, which enhances actin filament stabilization. Microtubules and myosin II contribute to but are not required for formation of model Hirano bodies. PMID:24632241

Making the invisible visible: improved electrospray ion formation of metalloporphyrins/-phthalocyanines by attachment of the formate anion (HCOO(-)).

PubMed

Hitzenberger, Jakob Felix; Dammann, Claudia; Lang, Nina; Lungerich, Dominik; García-Iglesias, Miguel; Bottari, Giovanni; Torres, Tomás; Jux, Norbert; Drewello, Thomas

2016-02-21

A protocol is developed for the coordination of the formate anion (HCOO(-)) to neutral metalloporphyrins (Pors) and -phthalocyanines (Pcs) containing divalent metals as a means to improve their ion formation in electrospray ionization (ESI). This method is particularly useful when the oxidation of the neutral metallomacrocycle fails. While focusing on Zn(II)Pors and Zn(II)Pcs, we show that formate is also readily attached to Mn(II), Mg(II) and Co(II)Pcs. However, for the Co(II)Pc secondary reactions can be observed. Upon collision-induced dissociation (CID), Zn(II)Por/Pc·formate supramolecular complexes can undergo the loss of CO2 in combination with transfer of a hydride anion (H(-)) to the zinc metal center. Further dissociation leads to electron transfer and hydrogen atom loss, generating a route to the radical anion of the Zn(II)Por/Pc without the need for electrochemical reduction, although the Zn(II)Por/Pc may have a too low electron affinity to allow electron transfer directly from the formate anion. In addition to single Por molecules, multi Por arrays were successfully analyzed by this method. In this case, multiple addition of formate occurs, giving rise to multiply charged species. In these multi Por arrays, complexation of the formate anion occurs by two surrounding Por units (sandwich). Therefore, the maximum attainment of formate anions in these arrays corresponds to the number of such sandwich complexes rather than the number of porphyrin moieties. The same bonding motif leads to dimers of the composition [(Zn(II)Por/Pc)2·HCOO](-). In these, the formate anion can act as a structural probe, allowing the distinction of isomeric ions with the formate bridging two macrocycles or being attached to a dimer of directly connected macrocycles.

Maggot excretions inhibit biofilm formation on biomaterials.

PubMed

Cazander, Gwendolyn; van de Veerdonk, Mariëlle C; Vandenbroucke-Grauls, Christina M J E; Schreurs, Marco W J; Jukema, Gerrolt N

2010-10-01

Biofilm-associated infections in trauma surgery are difficult to treat with conventional therapies. Therefore, it is important to develop new treatment modalities. Maggots in captured bags, which are permeable for larval excretions/secretions, aid in healing severe, infected wounds, suspect for biofilm formation. Therefore we presumed maggot excretions/secretions would reduce biofilm formation. We studied biofilm formation of Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella oxytoca, Enterococcus faecalis, and Enterobacter cloacae on polyethylene, titanium, and stainless steel. We compared the quantities of biofilm formation between the bacterial species on the various biomaterials and the quantity of biofilm formation after various incubation times. Maggot excretions/secretions were added to existing biofilms to examine their effect. Comb-like models of the biomaterials, made to fit in a 96-well microtiter plate, were incubated with bacterial suspension. The formed biofilms were stained in crystal violet, which was eluted in ethanol. The optical density (at 595 nm) of the eluate was determined to quantify biofilm formation. Maggot excretions/secretions were pipetted in different concentrations to (nonstained) 7-day-old biofilms, incubated 24 hours, and finally measured. The strongest biofilms were formed by S. aureus and S. epidermidis on polyethylene and the weakest on titanium. The highest quantity of biofilm formation was reached within 7 days for both bacteria. The presence of excretions/secretions reduced biofilm formation on all biomaterials. A maximum of 92% of biofilm reduction was measured. Our observations suggest maggot excretions/secretions decrease biofilm formation and could provide a new treatment for biofilm formation on infected biomaterials.

Ka-Band Autonomous Formation Flying Sensor

NASA Technical Reports Server (NTRS)

Tien, Jeffrey; Purcell, George, Jr.; Srinivasan, Jeffrey; Ciminera, Michael; Srinivasan, Meera; Meehan, Thomas; Young, Lawrence; Aung, MiMi; Amaro, Luis; Chong, Yong;

Planet formation

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

1993-01-01

Models of planetary formation are developed using the present single example of a planetary system, supplemented by limited astrophysical observations of star-forming regions and circumstellar disks. The solar nebula theory and the planetesimal hypothesis are discussed. The latter is found to provide a viable theory of the growth of the terrestrial planets, the cores of the giant planets, and the smaller bodies present in the solar system. The formation of solid bodies of planetary size should be a common event, at least around young stars which do not have binary companions orbiting at planetary distances. Stochastic impacts of large bodies provide sufficient angular momentum to produce the obliquities of the planets. The masses and bulk compositions of the planets can be understood in a gross sense as resulting from planetary growth within a disk whose temperature and surface density decreased with distance from the growing sun.

Heating tar sands formations while controlling pressure

DOEpatents

Stegemeier, George Leo [Houston, TX; Beer, Gary Lee [Houston, TX; Zhang, Etuan [Houston, TX

2010-01-12

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

The Effects of Formative Assessment with Detailed Feedback on Students' Science Learning Achievement and Attitudes Regarding Formative Assessment.

ERIC Educational Resources Information Center

Choi, Kyunghee; Nam, Jeong-Hee; Lee, Hyunju

2001-01-01

Examines the effects of a formative assessment with detailed feedback on students' science learning achievement and attitudes regarding formative assessment. Involves (n=133) ninth grade students from Seoul and administers pre- and post-tests for learning achievement and attitude regarding formative assessment. (Contains 16 references.)…

Nonuniversal star formation efficiency in turbulent ISM

DOE PAGES

Semenov, Vadim A.; Kravtsov, Andrey V.; Gnedin, Nickolay Y.

2016-07-29

Here, we present a study of a star formation prescription in which star formation efficiency depends on local gas density and turbulent velocity dispersion, as suggested by direct simulations of SF in turbulent giant molecular clouds (GMCs). We test the model using a simulation of an isolated Milky Way-sized galaxy with a self-consistent treatment of turbulence on unresolved scales. We show that this prescription predicts a wide variation of local star formation efficiency per free-fall time,more » $$\\epsilon_{\\rm ff} \\sim 0.1 - 10\\%$$, and gas depletion time, $$t_{\\rm dep} \\sim 0.1 - 10$$ Gyr. In addition, it predicts an effective density threshold for star formation due to suppression of $$\\epsilon_{\\rm ff}$$ in warm diffuse gas stabilized by thermal pressure. We show that the model predicts star formation rates in agreement with observations from the scales of individual star-forming regions to the kiloparsec scales. This agreement is non-trivial, as the model was not tuned in any way and the predicted star formation rates on all scales are determined by the distribution of the GMC-scale densities and turbulent velocities $$\\sigma$$ in the cold gas within the galaxy, which is shaped by galactic dynamics. The broad agreement of the star formation prescription calibrated in the GMC-scale simulations with observations, both gives credence to such simulations and promises to put star formation modeling in galaxy formation simulations on a much firmer theoretical footing.« less

The edge of galaxy formation - I. Formation and evolution of MW-satellite analogues before accretion

NASA Astrophysics Data System (ADS)

Macciò, Andrea V.; Frings, Jonas; Buck, Tobias; Penzo, Camilla; Dutton, Aaron A.; Blank, Marvin; Obreja, Aura

2017-12-01

The satellites of the Milky Way and Andromeda represent the smallest galaxies we can observe in our Universe. In this series of papers, we aim to shed light on their formation and evolution using cosmological hydrodynamical simulations. In this first paper, we focus on the galaxy properties before accretion, by simulating 27 haloes with masses between 5 × 108 and 1010 M⊙. Out of this set 19 haloes successfully form stars, while 8 remain dark. The simulated galaxies match quite well present day observed scaling relations between stellar mass, size and metallicity, showing that such relations are in place before accretion. Our galaxies show a large variety of star formation histories, from extended star formation periods to single bursts. As in more massive galaxies, large star formation bursts are connected with major mergers events, which greatly contribute to the overall stellar mass build up. The intrinsic stochasticity of mergers induces a large scatter in the stellar mass-halo mass relation, up to two orders of magnitude. Despite the bursty star formation history, on these mass scales baryons are very ineffective in modifying the dark matter profiles, and galaxies with a stellar mass below ≈106 M⊙ retain their cuspy central dark matter distribution, very similar to results from pure N-body simulations.

1 CFR 10.3 - Format.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 1 General Provisions 1 2010-01-01 2010-01-01 false Format. 10.3 Section 10.3 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER SPECIAL EDITIONS OF THE FEDERAL REGISTER PRESIDENTIAL PAPERS Regular Publication § 10.3 Format. The Daily Compilation of Presidential Documents is published online on...

1 CFR 10.3 - Format.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 1 General Provisions 1 2011-01-01 2011-01-01 false Format. 10.3 Section 10.3 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER SPECIAL EDITIONS OF THE FEDERAL REGISTER PRESIDENTIAL PAPERS Regular Publication § 10.3 Format. The Daily Compilation of Presidential Documents is published online on...

Professional Development through Formative Evaluation

ERIC Educational Resources Information Center

Nsibande, Rejoice; Garraway, James

2011-01-01

Formative evaluation and its associated methodology of reflection on practice are used extensively in academic staff development. In reflecting on formative evaluation processes in both more traditional and newer programmes conducted at a university of technology, a number of variables reported in the literature were observed to have influenced…

1 CFR 10.3 - Format.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 1 General Provisions 1 2014-01-01 2012-01-01 true Format. 10.3 Section 10.3 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER SPECIAL EDITIONS OF THE FEDERAL REGISTER PRESIDENTIAL PAPERS Regular Publication § 10.3 Format. The Daily Compilation of Presidential Documents is published online on...

1 CFR 10.3 - Format.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 1 General Provisions 1 2013-01-01 2012-01-01 true Format. 10.3 Section 10.3 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER SPECIAL EDITIONS OF THE FEDERAL REGISTER PRESIDENTIAL PAPERS Regular Publication § 10.3 Format. The Daily Compilation of Presidential Documents is published online on...

1 CFR 10.3 - Format.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 1 General Provisions 1 2012-01-01 2012-01-01 false Format. 10.3 Section 10.3 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER SPECIAL EDITIONS OF THE FEDERAL REGISTER PRESIDENTIAL PAPERS Regular Publication § 10.3 Format. The Daily Compilation of Presidential Documents is published online on...

SW New Mexico Oil Well Formation Tops

DOE Data Explorer

Shari Kelley

2015-10-21

Rock formation top picks from oil wells from southwestern New Mexico from scout cards and other sources. There are differing formation tops interpretations for some wells, so for those wells duplicate formation top data are presented in this file.

Treating nahcolite containing formations and saline zones

DOEpatents

Vinegar, Harold J

2013-06-11

A method for treating a nahcolite containing subsurface formation includes removing water from a saline zone in or near the formation. The removed water is heated using a steam and electricity cogeneration facility. The heated water is provided to the nahcolite containing formation. A fluid is produced from the nahcolite containing formation. The fluid includes at least some dissolved nahcolite. At least some of the fluid is provided to the saline zone.

Star formation across galactic environments

NASA Astrophysics Data System (ADS)

Young, Jason

I present here parallel investigations of star formation in typical and extreme galaxies. The typical galaxies are selected to be free of active galactic nuclei (AGN), while the extreme galaxies host quasars (the most luminous class of AGN). These two environments are each insightful in their own way; quasars are among the most violent objects in the universe, literally reshaping their host galaxies, while my sample of AGN-free star-forming galaxies ranges from systems larger than the Milky Way to small galaxies which are forming stars at unsustainably high rates. The current paradigm of galaxy formation and evolution suggests that extreme circumstances are key stepping stones in the assembly of galaxies like our Milky Way. To test this paradigm and fully explore its ramifications, this dual approach is needed. My sample of AGN-free galaxies is drawn from the KPNO International Spectroscopic Survey. This Halpha-selected, volume-limited survey was designed to detect star-forming galaxies without a bias toward continuum luminosity. This type of selection ensures that this sample is not biased toward galaxies that are large or nearby. My work studies the KISS galaxies in the mid- and far-infrared using photometry from the IRAC and MIPS instruments aboard the Spitzer Space Telescope. These infrared bands are particularly interesting for star formation studies because the ultraviolet light from young stars is reprocessed into thermal emission in the far-infrared (24mum MIPS) by dust and into vibrational transitions features in the mid-infrared (8.0mum IRAC) by polycyclic aromatic hydrocarbons (PAHs). The work I present here examines the efficiencies of PAH and thermal dust emission as tracers of star-formation rates over a wide range of galactic stellar masses. I find that the efficiency of PAH as a star-formation tracer varies with galactic stellar mass, while thermal dust has a highly variable efficiency that does not systematically depend on galactic stellar mass

Stratigraphic correlation of the Late Cretaceous Simsima Formation United Arab Emirates and Akveren Formation, northwest Turkey

NASA Astrophysics Data System (ADS)

Abdelghany, O.; Abu Saima, M.; Ramazanoglu, S.; Arman, H.

2015-11-01

Latest Cretaceous (Campanian-Maastrichtian) microfossils are used to correlate the carbonate rocks of the Simsima Formation in the northeastern part of the Arabian Peninsula (Northern Oman Mountains, United Arab Emirates and Oman) with the Akveren Formation in Kandira (northwest Turkey, near Black Sea region). Both formations have characteristically rich planktonic foraminiferal and calcareous nannofossil faunal assemblages that permit the recognition of the Globotruncanella havanensis Zone and Quadrum sissinghii Zone CC22. The palaeontological data is used to build an appropriate palaeoenvironmental model for the latest Cretaceous Aruma Group in the Oman Mountains foreland basin. The study reveals that the Late Cretaceous formations of UAE and Turkey can be divided into an open marine carbonate shelf facies (planktonic foraminifera/calcareous nannofossil biomicrite) and a shallow-marine carbonate facies (rudistids, coralline algal foraminiferal biomicrite).

Combined EXAFS Spectroscopic and Quantum Chemical Study on the Complex Formation of Am(III) with Formate.

PubMed

Fröhlich, Daniel R; Kremleva, Alena; Rossberg, André; Skerencak-Frech, Andrej; Koke, Carsten; Krüger, Sven; Rösch, Notker; Panak, Petra J

2017-06-19

The complexation of Am(III) with formate in aqueous solution is studied as a function of the pH value using a combination of extended X-ray absorption fine structure (EXAFS) spectroscopy, iterative transformation factor analysis (ITFA), and quantum chemical calculations. The Am L III -edge EXAFS spectra are analyzed to determine the molecular structure (coordination numbers; Am-O and Am-C distances) of the formed Am(III)-formate species and to track the shift of the Am(III) speciation with increasing pH. The experimental data are compared to predictions from density functional calculations. The results indicate that formate binds to Am(III) in a monodentate fashion, in agreement with crystal structures of lanthanide formates. Furthermore, the investigations are complemented by thermodynamic speciation calculations to verify further the results obtained.

7 CFR 51.605 - Good heart formation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Good heart formation. 51.605 Section 51.605....605 Good heart formation. Good heart formation means that the stalk has a reasonable number of stocky inner heart branches for its size. ...

7 CFR 51.605 - Good heart formation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Good heart formation. 51.605 Section 51.605....605 Good heart formation. Good heart formation means that the stalk has a reasonable number of stocky inner heart branches for its size. ...

The turbulent formation of stars

NASA Astrophysics Data System (ADS)

Federrath, Christoph

2018-06-01

How stars are born from clouds of gas is a rich physics problem whose solution will inform our understanding of not just stars but also planets, galaxies, and the universe itself. Star formation is stupendously inefficient. Take the Milky Way. Our galaxy contains about a billion solar masses of fresh gas available to form stars-and yet it produces only one solar mass of new stars a year. Accounting for that inefficiency is one of the biggest challenges of modern astrophysics. Why should we care about star formation? Because the process powers the evolution of galaxies and sets the initial conditions for planet formation and thus, ultimately, for life.

Occurrence of Sarcocystis falcatula in captive psittacine birds in Brazil.

PubMed

Godoy, Silvia Neri; De Paula, Catia Dejuste; Cubas, Zalmir Silvino; Matushima, Eliana Reiko; Catão-Dias, José Luiz

2009-03-01

Thirty-eight captive psittacine birds housed in a bird park in Foz do Iguaçu, Parana, Brazil, died within a 15-month period as a result of infection with Sarcocystis falcatula. Although fatalities affected 16 species of psittacine birds, mortality was highest in Old World species, which were most susceptible to the pulmonary form of sarcocystosis. Along with the pathologic findings of this disease outbreak, a review of the pathophysiology of sarcosporidiosis is presented.

Evaluation of new multimedia formats for cancer communications.

PubMed

Bader, Judith L; Strickman-Stein, Nancy

2003-01-01

Providing quality, current cancer information to cancer patients and their families is a key function of the National Cancer Institute (NCI) Web site. This information is now provided in predominantly-text format, but could be provided in formats using multimedia, including animation and sound. Since users have many choices about where to get their information, it is important to provide the information in a format that is helpful and that they prefer. To pilot and evaluate multimedia strategies for future cancer-information program formats for lay users, the National Cancer Institute created new multimedia versions of existing text programs. We sought to evaluate user performance and preference on these 3 new formats and on the 2 existing text formats. The National Cancer Institute's "What You Need to Know About Lung Cancer" program was the test vehicle. There were 5 testing sessions, 1 dedicated to each format. Each session lasted about 1 hour, with 9 participants per session and 45 users overall. Users were exposed to the assigned cancer program from beginning to end in 1 of 5 formats: text paperback booklet, paperback booklet formatted in HTML on the Web, spoken audio alone, spoken audio synchronized with a text Web page, and Flash multimedia (animation, spoken audio, and text). Immediately thereafter, the features and design of the 4 alternative formats were demonstrated in detail. A multiple-choice pre-test and post-test quiz on the cancer content was used to assess user learning (performance) before and after experiencing the assigned program. The quiz was administered using an Authorware software interface writing to an Access database. Users were asked to rank from 1 to 5 their preference for the 5 program formats, and provide structured and open-ended comments about usability of the 5 formats. Significant improvement in scores from pre-test to post-test was seen for the total study population. Average scores for users in each of the 5 format groups

Evaluation of New Multimedia Formats for Cancer Communications

PubMed Central

Strickman-Stein, Nancy

2003-01-01

Background Providing quality, current cancer information to cancer patients and their families is a key function of the National Cancer Institute (NCI) Web site. This information is now provided in predominantly-text format, but could be provided in formats using multimedia, including animation and sound. Since users have many choices about where to get their information, it is important to provide the information in a format that is helpful and that they prefer. Objective To pilot and evaluate multimedia strategies for future cancer-information program formats for lay users, the National Cancer Institute created new multimedia versions of existing text programs. We sought to evaluate user performance and preference on these 3 new formats and on the 2 existing text formats. Methods The National Cancer Institute's "What You Need to Know About Lung Cancer" program was the test vehicle. There were 5 testing sessions, 1 dedicated to each format. Each session lasted about 1 hour, with 9 participants per session and 45 users overall. Users were exposed to the assigned cancer program from beginning to end in 1 of 5 formats: text paperback booklet, paperback booklet formatted in HTML on the Web, spoken audio alone, spoken audio synchronized with a text Web page, and Flash multimedia (animation, spoken audio, and text). Immediately thereafter, the features and design of the 4 alternative formats were demonstrated in detail. A multiple-choice pre-test and post-test quiz on the cancer content was used to assess user learning (performance) before and after experiencing the assigned program. The quiz was administered using an Authorware software interface writing to an Access database. Users were asked to rank from 1 to 5 their preference for the 5 program formats, and provide structured and open-ended comments about usability of the 5 formats. Results Significant improvement in scores from pre-test to post-test was seen for the total study population. Average scores for users

SAS FORMATS: USES AND ABUSES

EPA Science Inventory

SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As ...

SAS FORMATS: USES AND ABUSES

EPA Science Inventory

SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As w...

Bacterial formate hydrogenlyase complex.

PubMed

McDowall, Jennifer S; Murphy, Bonnie J; Haumann, Michael; Palmer, Tracy; Armstrong, Fraser A; Sargent, Frank

2014-09-23

Under anaerobic conditions, Escherichia coli can carry out a mixed-acid fermentation that ultimately produces molecular hydrogen. The enzyme directly responsible for hydrogen production is the membrane-bound formate hydrogenlyase (FHL) complex, which links formate oxidation to proton reduction and has evolutionary links to Complex I, the NADH:quinone oxidoreductase. Although the genetics, maturation, and some biochemistry of FHL are understood, the protein complex has never been isolated in an intact form to allow biochemical analysis. In this work, genetic tools are reported that allow the facile isolation of FHL in a single chromatographic step. The core complex is shown to comprise HycE (a [NiFe] hydrogenase component termed Hyd-3), FdhF (the molybdenum-dependent formate dehydrogenase-H), and three iron-sulfur proteins: HycB, HycF, and HycG. A proportion of this core complex remains associated with HycC and HycD, which are polytopic integral membrane proteins believed to anchor the core complex to the cytoplasmic side of the membrane. As isolated, the FHL complex retains formate hydrogenlyase activity in vitro. Protein film electrochemistry experiments on Hyd-3 demonstrate that it has a unique ability among [NiFe] hydrogenases to catalyze production of H2 even at high partial pressures of H2. Understanding and harnessing the activity of the FHL complex is critical to advancing future biohydrogen research efforts.

FORMATION OF SECONDARY ORGANIC AEROSOL

EPA Science Inventory

(1) Gas-phase chemistry. With the clear and profound effect of the VOC/NO_x ratio on SOA formation, we will augment gas-phase VOC oxidation mechanisms in atmospheric models to account for the effect of NO_x level on the mechanism of SOA formation; (2) Revis...

11 CFR 9428.5 - Format.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 11 Federal Elections 1 2010-01-01 2010-01-01 false Format. 9428.5 Section 9428.5 Federal Elections ELECTION ASSISTANCE COMMISSION NATIONAL VOTER REGISTRATION ACT (42 U.S.C. 1973gg-1 et seq.) National Mail Voter Registration Form § 9428.5 Format. (a) The application shall conform to the technical...

Formation Stellaire Aux Échelles Des Galaxies

NASA Astrophysics Data System (ADS)

Boissier, S.

2012-12-01

Star Formation is at the very core of the evolution of galaxies. From their gas reservoir (filled by infall or fusions), stars form at the "Star Formation Rate" (SFR), with an enormous impact on many aspects of the evolution of galaxies. This HDR presents first the formalism concerning star formation (SFR, IMF), some theoretical suggestions on physical processes that may affect star formation on various galactic scales, and the methods used to determine the SFR from observations. A large part is dedicated to the "Star Formation Laws" (e.g. Schmidt law) on various scales (local, radial, and global law). Finally, the last part concerns the largest scales (evolution of the "cosmic" SFR and effect of the environment).

Improving the Factor Structure of Psychological Scales: The Expanded Format as an Alternative to the Likert Scale Format

ERIC Educational Resources Information Center

Zhang, Xijuan; Savalei, Victoria

2016-01-01

Many psychological scales written in the Likert format include reverse worded (RW) items in order to control acquiescence bias. However, studies have shown that RW items often contaminate the factor structure of the scale by creating one or more method factors. The present study examines an alternative scale format, called the Expanded format,…

Enhancing Collaborative and Meaningful Language Learning Through Concept Mapping

NASA Astrophysics Data System (ADS)

Marriott, Rita De Cássia Veiga; Torres, Patrícia Lupion

This chapter aims to investigate new ways of foreign-language teaching/learning via a study of how concept mapping can help develop a student's reading, writing and oral skills as part of a blended methodology for language teaching known as LAPLI (Laboratorio de Aprendizagem de LInguas: The Language Learning Lab). LAPLI is a student-centred and collaborative methodology which encourages students to challenge their limitations and expand their current knowledge whilst developing their linguistic and interpersonal skills. We explore the theories that underpin LAPLI and detail the 12 activities comprising its programme with specify reference to the use of "concept mapping". An innovative table enabling a formative and summative assessment of the concept maps is formulated. Also presented are some of the qualitative and quantitative results achieved when this methodology was first implemented with a group of pre-service students studying for a degree in English and Portuguese languages at the Catholic University of Parana (PUCPR) in Brazil. The contribution of concept mapping and LAPLI to an under standing of language learning along with a consideration of the difficulties encountered in its implementation with student groups is discussed and suggestions made for future research.

Enhancing Collaborative and Meaningful Language Learning through Concept Mapping

NASA Astrophysics Data System (ADS)

de Cássia Veiga Marriott, Rita; Torres, Patrícia Lupion

This chapter aims to investigate new ways of foreign-language teaching/learning via a study of how concept mapping can help develop a student's reading, writing and oral skills as part of a blended methodology for language teaching known as LAPLI (Laboratorio de Aprendizagem de LInguas: The Language Learning Lab). LAPLI is a student-centred and collaborative methodology which encourages students to challenge their limitations and expand their current knowledge whilst developing their linguistic and interpersonal skills. We explore the theories that underpin LAPLI and detail the 12 activities comprising its programme with specify reference to the use of “concept mapping”. An innovative table enabling a formative and summative assessment of the concept maps is formulated. Also presented are some of the qualitative and quantitative results achieved when this methodology was first implemented with a group of pre-service students studying for a degree in English and Portuguese languages at the Catholic University of Parana (PUCPR) in Brazil. The contribution of concept mapping and LAPLI to an understanding of language learning along with a consideration of the difficulties encountered in its implementation with student groups is discussed and suggestions made for future research.

Reducing Formation-Keeping Maneuver Costs for Formation Flying Satellites in Low-Earth Orbit

NASA Technical Reports Server (NTRS)

Hamilton, Nicholas

2001-01-01

Several techniques are used to synthesize the formation-keeping control law for a three-satellite formation in low-earth orbit. The objective is to minimize maneuver cost and position tracking error. Initial reductions are found for a one-satellite case by tuning the state-weighting matrix within the linear-quadratic-Gaussian framework. Further savings come from adjusting the maneuver interval. Scenarios examined include cases with and without process noise. These results are then applied to a three-satellite formation. For both the one-satellite and three-satellite cases, increasing the maneuver interval yields a decrease in maneuver cost and an increase in position tracking error. A maneuver interval of 8-10 minutes provides a good trade-off between maneuver cost and position tracking error. An analysis of the closed-loop poles with respect to varying maneuver intervals explains the effectiveness of the chosen maneuver interval.

Formation Flying in Earth, Libration, and Distant Retrograde Orbits

NASA Technical Reports Server (NTRS)

Folta, David C.

2004-01-01

This slide presentation examines the current and future state of formation flying, LEO formations, control strategies for flight in the vicinity of the libration points, and distant retrograde orbit formations. This discussion of LEO formations includes background on perturbation theory/accelerations and LEO formation flying. The discussion of strategies for formation flight in the vicinity of the libration points includes libration missions and natural and controlled libration orbit formations. A reference list is included.

Mass spectrometer output file format mzML.

PubMed

Deutsch, Eric W

2010-01-01

Mass spectrometry is an important technique for analyzing proteins and other biomolecular compounds in biological samples. Each of the vendors of these mass spectrometers uses a different proprietary binary output file format, which has hindered data sharing and the development of open source software for downstream analysis. The solution has been to develop, with the full participation of academic researchers as well as software and hardware vendors, an open XML-based format for encoding mass spectrometer output files, and then to write software to use this format for archiving, sharing, and processing. This chapter presents the various components and information available for this format, mzML. In addition to the XML schema that defines the file structure, a controlled vocabulary provides clear terms and definitions for the spectral metadata, and a semantic validation rules mapping file allows the mzML semantic validator to insure that an mzML document complies with one of several levels of requirements. Complete documentation and example files insure that the format may be uniformly implemented. At the time of release, there already existed several implementations of the format and vendors have committed to supporting the format in their products.

Mapping DICOM to OpenDocument format

NASA Astrophysics Data System (ADS)

Yu, Cong; Yao, Zhihong

2009-02-01

In order to enhance the readability, extensibility and sharing of DICOM files, we have introduced XML into DICOM file system (SPIE Volume 5748)[1] and the multilayer tree structure into DICOM (SPIE Volume 6145)[2]. In this paper, we proposed mapping DICOM to ODF(OpenDocument Format), for it is also based on XML. As a result, the new format realizes the separation of content(including text content and image) and display style. Meanwhile, since OpenDocument files take the format of a ZIP compressed archive, the new kind of DICOM files can benefit from ZIP's lossless compression to reduce file size. Moreover, this open format can also guarantee long-term access to data without legal or technical barriers, making medical images accessible to various fields.

A Socio-Cultural Theorisation of Formative Assessment

ERIC Educational Resources Information Center

Pryor, John; Crossouard, Barbara

2008-01-01

Formative assessment has attracted increasing attention from both practitioners and scholars over the last decade. This paper draws on the authors' empirical research conducted over eleven years in educational situations ranging from infant schools to postgraduate education to propose a theorisation of formative assessment. Formative assessment is…

H2-based star formation laws in hierarchical models of galaxy formation

NASA Astrophysics Data System (ADS)

Xie, Lizhi; De Lucia, Gabriella; Hirschmann, Michaela; Fontanot, Fabio; Zoldan, Anna

2017-07-01

We update our recently published model for GAlaxy Evolution and Assembly (GAEA), to include a self-consistent treatment of the partition of cold gas in atomic and molecular hydrogen. Our model provides significant improvements with respect to previous ones used for similar studies. In particular, GAEA (I) includes a sophisticated chemical enrichment scheme accounting for non-instantaneous recycling of gas, metals and energy; (II) reproduces the measured evolution of the galaxy stellar mass function; (III) reasonably reproduces the observed correlation between galaxy stellar mass and gas metallicity at different redshifts. These are important prerequisites for models considering a metallicity-dependent efficiency of molecular gas formation. We also update our model for disc sizes and show that model predictions are in nice agreement with observational estimates for the gas, stellar and star-forming discs at different cosmic epochs. We analyse the influence of different star formation laws including empirical relations based on the hydrostatic pressure of the disc, analytic models and prescriptions derived from detailed hydrodynamical simulations. We find that modifying the star formation law does not affect significantly the global properties of model galaxies, neither their distributions. The only quantity showing significant deviations in different models is the cosmic molecular-to-atomic hydrogen ratio, particularly at high redshift. Unfortunately, however, this quantity also depends strongly on the modelling adopted for additional physical processes. Useful constraints on the physical processes regulating star formation can be obtained focusing on low-mass galaxies and/or at higher redshift. In this case, self-regulation has not yet washed out differences imprinted at early time.

Autonomous formation flight of helicopters: Model predictive control approach

NASA Astrophysics Data System (ADS)

Chung, Hoam

Formation flight is the primary movement technique for teams of helicopters. However, the potential for accidents is greatly increased when helicopter teams are required to fly in tight formations and under harsh conditions. This dissertation proposes that the automation of helicopter formations is a realistic solution capable of alleviating risks. Helicopter formation flight operations in battlefield situations are highly dynamic and dangerous, and, therefore, we maintain that both a high-level formation management system and a distributed coordinated control algorithm should be implemented to help ensure safe formations. The starting point for safe autonomous formation flights is to design a distributed control law attenuating external disturbances coming into a formation, so that each vehicle can safely maintain sufficient clearance between it and all other vehicles. While conventional methods are limited to homogeneous formations, our decentralized model predictive control (MPC) approach allows for heterogeneity in a formation. In order to avoid the conservative nature inherent in distributed MPC algorithms, we begin by designing a stable MPC for individual vehicles, and then introducing carefully designed inter-agent coupling terms in a performance index. Thus the proposed algorithm works in a decentralized manner, and can be applied to the problem of helicopter formations comprised of heterogenous vehicles. Individual vehicles in a team may be confronted by various emerging situations that will require the capability for in-flight reconfiguration. We propose the concept of a formation manager to manage separation, join, and synchronization of flight course changes. The formation manager accepts an operator's commands, information from neighboring vehicles, and its own vehicle states. Inside the formation manager, there are multiple modes and complex mode switchings represented as a finite state machine (FSM). Based on the current mode and collected

Heating tar sands formations to visbreaking temperatures

DOEpatents

Karanikas, John Michael [Houston, TX; Colmenares, Tulio Rafael [Houston, TX; Zhang, Etuan [Houston, TX; Marino, Marian [Houston, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Ryan, Robert Charles [Houston, TX; Beer, Gary Lee [Houston, TX; Dombrowski, Robert James [Houston, TX; Jaiswal, Namit [Houston, TX

2009-12-22

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

Interoperability format translation and transformation between IFC architectural design file and simulation file formats

DOEpatents

Chao, Tian-Jy; Kim, Younghun

2015-02-03

Automatically translating a building architecture file format (Industry Foundation Class) to a simulation file, in one aspect, may extract data and metadata used by a target simulation tool from a building architecture file. Interoperability data objects may be created and the extracted data is stored in the interoperability data objects. A model translation procedure may be prepared to identify a mapping from a Model View Definition to a translation and transformation function. The extracted data may be transformed using the data stored in the interoperability data objects, an input Model View Definition template, and the translation and transformation function to convert the extracted data to correct geometric values needed for a target simulation file format used by the target simulation tool. The simulation file in the target simulation file format may be generated.

Star formation in the multiverse

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

Bousso, Raphael; Leichenauer, Stefan

2009-03-15

We develop a simple semianalytic model of the star formation rate as a function of time. We estimate the star formation rate for a wide range of values of the cosmological constant, spatial curvature, and primordial density contrast. Our model can predict such parameters in the multiverse, if the underlying theory landscape and the cosmological measure are known.

Mantle dynamics following supercontinent formation

NASA Astrophysics Data System (ADS)

Heron, Philip J.

This thesis presents mantle convection numerical simulations of supercontinent formation. Approximately 300 million years ago, through the large-scale subduction of oceanic sea floor, continental material amalgamated to form the supercontinent Pangea. For 100 million years after its formation, Pangea remained relatively stationary, and subduction of oceanic material featured on its margins. The present-day location of the continents is due to the rifting apart of Pangea, with supercontinent dispersal being characterized by increased volcanic activity linked to the generation of deep mantle plumes. The work presented here investigates the thermal evolution of mantle dynamics (e.g., mantle temperatures and sub-continental plumes) following the formation of a supercontinent. Specifically, continental insulation and continental margin subduction are analyzed. Continental material, as compared to oceanic material, inhibits heat flow from the mantle. Previous numerical simulations have shown that the formation of a stationary supercontinent would elevate sub-continental mantle temperatures due to the effect of continental insulation, leading to the break-up of the continent. By modelling a vigorously convecting mantle that features thermally and mechanically distinct continental and oceanic plates, this study shows the effect of continental insulation on the mantle to be minimal. However, the formation of a supercontinent results in sub-continental plume formation due to the re-positioning of subduction zones to the margins of the continent. Accordingly, it is demonstrated that continental insulation is not a significant factor in producing sub-supercontinent plumes but that subduction patterns control the location and timing of upwelling formation. A theme throughout the thesis is an inquiry into why geodynamic studies would produce different results. Mantle viscosity, Rayleigh number, continental size, continental insulation, and oceanic plate boundary evolution are

The three phases of galaxy formation

NASA Astrophysics Data System (ADS)

Clauwens, Bart; Schaye, Joop; Franx, Marijn; Bower, Richard G.

2018-05-01

We investigate the origin of the Hubble sequence by analysing the evolution of the kinematic morphologies of central galaxies in the EAGLE cosmological simulation. By separating each galaxy into disc and spheroidal stellar components and tracing their evolution along the merger tree, we find that the morphology of galaxies follows a common evolutionary trend. We distinguish three phases of galaxy formation. These phases are determined primarily by mass, rather than redshift. For M* ≲ 109.5M⊙ galaxies grow in a disorganised way, resulting in a morphology that is dominated by random stellar motions. This phase is dominated by in-situ star formation, partly triggered by mergers. In the mass range 109.5M⊙ ≲ M* ≲ 1010.5M⊙ galaxies evolve towards a disc-dominated morphology, driven by in-situ star formation. The central spheroid (i.e. the bulge) at z = 0 consists mostly of stars that formed in-situ, yet the formation of the bulge is to a large degree associated with mergers. Finally, at M* ≳ 1010.5M⊙ growth through in-situ star formation slows down considerably and galaxies transform towards a more spheroidal morphology. This transformation is driven more by the buildup of spheroids than by the destruction of discs. Spheroid formation in these galaxies happens mostly by accretion at large radii of stars formed ex-situ (i.e. the halo rather than the bulge).

libvaxdata: VAX data format conversion routines

USGS Publications Warehouse

Baker, Lawrence M.

2005-01-01

libvaxdata provides a collection of routines for converting numeric data-integer and floating-point-to and from the formats used on a Digital Equipment Corporation1 (DEC) VAX 32-bit minicomputer (Brunner, 1991). Since the VAX numeric data formats are inherited from those used on a DEC PDP-11 16-bit minicomputer, these routines can be used to convert PDP-11 data as well. VAX numeric data formats are also the default data formats used on DEC Alpha 64-bit minicomputers running OpenVMS The libvaxdata routines are callable from Fortran or C. They require that the caller use two's-complement format for integer data and IEEE 754 format (ANSI/IEEE, 1985) for floating-point data. They also require that the 'natural' size of a C int type (integer) is 32 bits. That is the case for most modern 32-bit and 64-bit computer systems. Nevertheless, you may wish to consult the Fortran or C compiler documentation on your system to be sure. Some Fortran compilers support conversion of VAX numeric data on-the-fly when reading or writing unformatted files, either as a compiler option or a run-time I/O option. This feature may be easier to use than the libvaxdata routines. Consult the Fortran compiler documentation on your system to determine if this alternative is available to you. 1Later Compaq Computer Corporation, now Hewlett-Packard Company

MECHANISMS OF HUMAN KIDNEY STONE FORMATION

PubMed Central

Evan, Andrew P.; Worcester, Elaine M.; Coe, Fredric L.; Williams, James; Lingeman, James E.

2014-01-01

The precise mechanisms of kidney stone formation and growth are not completely known, even though human stone disease appears to be one of the oldest diseases known to medicine. With the advent of the new digital endoscope and detailed renal physiological studies performed on well phenotyped stone formers, substantial advances have been made in our knowledge of the pathogenesis of the most common type of stone former, the idiopathic calcium oxalate stone former (ICSF) as well as nine other stone forming groups. The observations from our group on human stone formers and those of others on model systems have suggested four entirely different pathways for kidney stone formation. Calcium oxalate stone growth over sites of Randall’s plaque appear to be the primary mode of stone formation for those patients with hypercalciuria. Overgrowths off the ends of Bellini duct plugs have been noted in most stone phenotypes, do they result in a clinical stone? Micro-lith formation does occur within the lumens of dilated inner medullary collecting ducts of cystinuric stone formers and appear to be confined to this space. Lastly, cystinuric stone formers also have numerous small, oval, smooth yellow appearing calyceal stones suggestive of formation in free solution. The scientific basis for each of these four modes of stone formation are reviewed and used to explore novel research opportunities. PMID:25108546

Distributed simulation for formation flying applications

NASA Technical Reports Server (NTRS)

Sohl, Garett A.; Udomkesmalee, Santi; Kellogg, Jennifer L.

2005-01-01

High fidelity engineering simulation plays a key role in the rapidly developing field of space-based formation flying. This paper describes the design and implementation of the Formation Algorithms and Simulation Testbed (FAST).

Star Formation Properties of Irregular Galaxies

NASA Astrophysics Data System (ADS)

Hunter, D. A.; Elmegreen, B. G.

2003-12-01

What regulates star formation in gas-rich dwarf galaxies on global and local scales? To address this question, we have conducted a survey of a large sample of reasonably normal, relatively nearby, non-interacting galaxies without spiral arms. The sample includes 94 Im galaxies, 26 Blue Compact Dwarfs, and 20 Sm systems. The data consist of UBV and Hα images for the entire sample, and JHK images, HI maps, CO observations, and HII region spectrophotometry for a sub-sample. The Hα , UBV, and JHK image sets act as probes of star formation on three different times scales: Hα images trace the most recent star formation (≤10 Myrs) through the ionization of natal clouds by the short-lived massive stars; UBV, while a more complicated clue, integrates over the past Gyr; and JHK integrates over the lifetime of the galaxy where even in Im galaxies global JHK colors are characteristic of old stellar populations. These data are being used to determine the nature and distribution of the star formation activity, to characterize the interstellar medium out of which the clouds and stars are forming, and to develop models that describe the important processes that drive star formation in these tiny systems. Here we present the Hα data: integrated star formation rates, azimuthally-averaged Hα surface brightnesses, and extents of star formation, and explore the relationship of the star formation properties to other integrated parameters of the galaxies. One TI CCD used in this work was provided to Lowell by the National Science Foundation and another was on loan from the U. S. Naval Observatory in Flagstaff. The Hα filters were purchased with funds provided by a Small Research Grant from the American Astronomical Society, National Science Foundation grant AST-9022046, and grant 960355 from JPL. Funding for carrying out this work was provided by the Lowell Research Fund and by the National Science Foundation through grants AST-0204922 to DAH and AST-0205097 to BGE.

7 CFR 51.605 - Good heart formation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Good heart formation. 51.605 Section 51.605... STANDARDS) United States Consumer Standards for Celery Stalks Definitions § 51.605 Good heart formation. Good heart formation means that the stalk has a reasonable number of stocky inner heart branches for...

7 CFR 51.605 - Good heart formation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Good heart formation. 51.605 Section 51.605... STANDARDS) United States Consumer Standards for Celery Stalks Definitions § 51.605 Good heart formation. Good heart formation means that the stalk has a reasonable number of stocky inner heart branches for...

7 CFR 51.605 - Good heart formation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Good heart formation. 51.605 Section 51.605... STANDARDS) United States Consumer Standards for Celery Stalks Definitions § 51.605 Good heart formation. Good heart formation means that the stalk has a reasonable number of stocky inner heart branches for...

Formative assessment: a student perspective.

PubMed

Hill, D A; Guinea, A I; McCarthy, W H

1994-09-01

An educator's view would be that formative assessment has an important role in the learning process. This study was carried out to obtain a student perspective of the place of formative assessment in the curriculum. Final-year medical students at Royal Prince Alfred Hospital took part in four teaching sessions, each structured to integrate teaching with assessment. Three assessment methods were used; the group objective structured clinical examination (G-OSCE), structured short answer (SSA) questions and a pre/post-test multiple choice questionnaire (MCQ). Teaching sessions were conducted on the subject areas of traumatology, the 'acute abdomen', arterial disorders and cancer. Fifty-five students, representing 83% of those who took part in the programme, responded to a questionnaire where they were asked to rate (on a 5-point Likert scale) their response to general questions about formative assessment and 13 specific questions concerning the comparative value of the three assessment modalities. Eighty-nine per cent of respondents felt that formative assessment should be incorporated into the teaching process. The SSA assessment was regarded as the preferred modality to reinforce previous teaching and test problem-solving skills. The MCQ was the least favoured assessment method. The effect size variable between the total scores for the SSA and MCQ was 0.64. The variable between G-OSCE and SSA/MCQ was 0.26 and 0.33 respectively. Formative assessment is a potentially powerful method to direct learning behaviour. Students should have input into the methods used.

Tetrahedron Formation Control

NASA Technical Reports Server (NTRS)

Petruzzo, Charles; Guzman, Jose

2004-01-01

This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include (1) targeting to a fixed tetrahedron location and orientation, and (2) rotating and translating the tetrahedron. The number of impulsive maneuvers can also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the NASA Goddard Magnetospheric Multi-Scale (MMS) mission to compute preliminary formation control fuel requirements.

Nearest pattern interaction and global pattern formation

NASA Astrophysics Data System (ADS)

Jeong, Seong-Ok; Moon, Hie-Tae; Ko, Tae-Wook

2000-12-01

We studied the effect of nearest pattern interaction on a global pattern formation in a two-dimensional space, where patterns are to grow initially from a noise in the presence of a periodic supply of energy. Although our approach is general, we found that this study is relevant in particular to the pattern formation on a periodically vibrated granular layer, as it gives a unified perspective of the experimentally observed pattern dynamics such as oscillon and stripe formations, skew-varicose and crossroll instabilities, and also a kink formation and decoration.

Increased formate overflow is a hallmark of oxidative cancer.

PubMed

Meiser, Johannes; Schuster, Anne; Pietzke, Matthias; Vande Voorde, Johan; Athineos, Dimitris; Oizel, Kristell; Burgos-Barragan, Guillermo; Wit, Niek; Dhayade, Sandeep; Morton, Jennifer P; Dornier, Emmanuel; Sumpton, David; Mackay, Gillian M; Blyth, Karen; Patel, Ketan J; Niclou, Simone P; Vazquez, Alexei

2018-04-10

Formate overflow coupled to mitochondrial oxidative metabolism\\ has been observed in cancer cell lines, but whether that takes place in the tumor microenvironment is not known. Here we report the observation of serine catabolism to formate in normal murine tissues, with a relative rate correlating with serine levels and the tissue oxidative state. Yet, serine catabolism to formate is increased in the transformed tissue of in vivo models of intestinal adenomas and mammary carcinomas. The increased serine catabolism to formate is associated with increased serum formate levels. Finally, we show that inhibition of formate production by genetic interference reduces cancer cell invasion and this phenotype can be rescued by exogenous formate. We conclude that increased formate overflow is a hallmark of oxidative cancers and that high formate levels promote invasion via a yet unknown mechanism.

An Algorithm for Autonomous Formation Obstacle Avoidance

NASA Astrophysics Data System (ADS)

Cruz, Yunior I.

The level of human interaction with Unmanned Aerial Systems varies greatly from remotely piloted aircraft to fully autonomous systems. In the latter end of the spectrum, the challenge lies in designing effective algorithms to dictate the behavior of the autonomous agents. A swarm of autonomous Unmanned Aerial Vehicles requires collision avoidance and formation flight algorithms to negotiate environmental challenges it may encounter during the execution of its mission, which may include obstacles and chokepoints. In this work, a simple algorithm is developed to allow a formation of autonomous vehicles to perform point to point navigation while avoiding obstacles and navigating through chokepoints. Emphasis is placed on maintaining formation structures. Rather than breaking formation and individually navigating around the obstacle or through the chokepoint, vehicles are required to assemble into appropriately sized/shaped sub-formations, bifurcate around the obstacle or negotiate the chokepoint, and reassemble into the original formation at the far side of the obstruction. The algorithm receives vehicle and environmental properties as inputs and outputs trajectories for each vehicle from start to the desired ending location. Simulation results show that the algorithm safely routes all vehicles past the obstruction while adhering to the aforementioned requirements. The formation adapts and successfully negotiates the obstacles and chokepoints in its path while maintaining proper vehicle separation.

String Formatting Considered Harmful for Novice Programmers

ERIC Educational Resources Information Center

Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

2010-01-01

In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found…

Transfer of Training with Formation Flight Trainer.

ERIC Educational Resources Information Center

Reid, Gary B.; Cyrus, Michael L.

The present research was conducted to determine transfer of practice from a formation simulator to actual aircraft flight for the wing aircraft component of the formation flying task. Evidence in support of positive transfer was obtained by comparing students trained in the formation simulator with students who were essentially untrained and with…

40 CFR 85.1905 - Alternative report formats.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Alternative report formats. 85.1905... Alternative report formats. (a) Any manufacturer may submit a plan for making either of the reports required by §§ 85.1903 and 85.1904 on computer cards, magnetic tape or other machine readable format. The...

40 CFR 85.1905 - Alternative report formats.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Alternative report formats. 85.1905... Alternative report formats. (a) Any manufacturer may submit a plan for making either of the reports required by §§ 85.1903 and 85.1904 on computer cards, magnetic tape or other machine readable format. The...

40 CFR 85.1905 - Alternative report formats.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Alternative report formats. 85.1905... Alternative report formats. (a) Any manufacturer may submit a plan for making either of the reports required by §§ 85.1903 and 85.1904 on computer cards, magnetic tape or other machine readable format. The...

40 CFR 85.1905 - Alternative report formats.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Alternative report formats. 85.1905... Alternative report formats. (a) Any manufacturer may submit a plan for making either of the reports required by §§ 85.1903 and 85.1904 on computer cards, magnetic tape or other machine readable format. The...

Planet Formation

NASA Astrophysics Data System (ADS)

Podolak, Morris

2018-04-01

Modern observational techniques are still not powerful enough to directly view planet formation, and so it is necessary to rely on theory. However, observations do give two important clues to the formation process. The first is that the most primitive form of material in interstellar space exists as a dilute gas. Some of this gas is unstable against gravitational collapse, and begins to contract. Because the angular momentum of the gas is not zero, it contracts along the spin axis, but remains extended in the plane perpendicular to that axis, so that a disk is formed. Viscous processes in the disk carry most of the mass into the center where a star eventually forms. In the process, almost as a by-product, a planetary system is formed as well. The second clue is the time required. Young stars are indeed observed to have gas disks, composed mostly of hydrogen and helium, surrounding them, and observations tell us that these disks dissipate after about 5 to 10 million years. If planets like Jupiter and Saturn, which are very rich in hydrogen and helium, are to form in such a disk, they must accrete their gas within 5 million years of the time of the formation of the disk. Any formation scenario one proposes must produce Jupiter in that time, although the terrestrial planets, which don't contain significant amounts of hydrogen and helium, could have taken longer to build. Modern estimates for the formation time of the Earth are of the order of 100 million years. To date there are two main candidate theories for producing Jupiter-like planets. The core accretion (CA) scenario supposes that any solid materials in the disk slowly coagulate into protoplanetary cores with progressively larger masses. If the core remains small enough it won't have a strong enough gravitational force to attract gas from the surrounding disk, and the result will be a terrestrial planet. If the core grows large enough (of the order of ten Earth masses), and the disk has not yet dissipated, then

Spacelab uplink/downlink data flow and formats

NASA Technical Reports Server (NTRS)

Kandefer, F.

1978-01-01

The results of an analysis of the Spacelab (SL) data uplink/downlink structure and those data system elements associated with the support of this data flow are presented. Specific objectives of this report are to present the results of the following analyses: (1) operations of the SL high rate multiplexer, including format structure, data rates, format combinations, format switching, etc.; (2) operations of SL data recorders to include the definition of modes, data rates and forms; (3) operations of the high rate demultiplexer as described above; (4) potential experiment data formats defining formatting parameters to be considered in decommutation analysis; (5) SL computer input/output (I/O) decommutation channels, including the definition of structure, quantity and use of this I/O data; (6) detailed requirements of the data quality monitoring philosophy for this function.

Method for laser drilling subterranean earth formations

DOEpatents

Shuck, Lowell Z.

1976-08-31

Laser drilling of subterranean earth formations is efficiently accomplished by directing a collimated laser beam into a bore hole in registry with the earth formation and transversely directing the laser beam into the earth formation with a suitable reflector. In accordance with the present invention, the bore hole is highly pressurized with a gas so that as the laser beam penetrates the earth formation the high pressure gas forces the fluids resulting from the drilling operation into fissures and pores surrounding the laser-drilled bore so as to inhibit deleterious occlusion of the laser beam. Also, the laser beam may be dynamically programmed with some time dependent wave form, e.g., pulsed, to thermally shock the earth formation for forming or enlarging fluid-receiving fissures in the bore.

Planetesimal formation starts at the snow line

NASA Astrophysics Data System (ADS)

Drążkowska, J.; Alibert, Y.

2017-12-01

Context. The formation stage of planetesimals represents a major gap in our understanding of the planet formation process. Late-stage planet accretion models typically make arbitrary assumptions about planetesimal and pebble distribution, while dust evolution models predict that planetesimal formation is only possible at some orbital distances. Aims: We wish to test the importance of the water snow line in triggering the formation of the first planetesimals during the gas-rich phase of a protoplanetary disk, when cores of giant planets have to form. Methods: We connected prescriptions for gas disk evolution, dust growth and fragmentation, water ice evaporation and recondensation, the transport of both solids and water vapor, and planetesimal formation via streaming instability into a single one-dimensional model for protoplanetary disk evolution. Results: We find that processes taking place around the snow line facilitate planetesimal formation in two ways. First, because the sticking properties between wet and dry aggregates change, a "traffic jam" inside of the snow line slows the fall of solids onto the star. Second, ice evaporation and outward diffusion of water followed by its recondensation increases the abundance of icy pebbles that trigger planetesimal formation via streaming instability just outside of the snow line. Conclusions: Planetesimal formation is hindered by growth barriers and radial drift and thus requires particular conditions to take place. The snow line is a favorable location where planetesimal formation is possible for a wide range of conditions, but not in every protoplanetary disk model, however. This process is particularly promoted in large cool disks with low intrinsic turbulence and an increased initial dust-to-gas ratio. The movie attached to Fig. 3 is only available at http://www.aanda.org

A Comparison of Formative and Summative Evaluation.

ERIC Educational Resources Information Center

Belenski, Mary Jo

Formative and summative evaluations in education are compared, and appropriate uses of these methods in program evaluation are discussed. The main purpose of formative evaluation is to determine a level of mastery of a learning task, along with discovering any part of the task that was not mastered. In other words, formative evaluation focuses the…

Terrestrial planet formation.

PubMed

Righter, K; O'Brien, D P

2011-11-29

Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

Terrestrial planet formation

PubMed Central

Righter, K.; O’Brien, D. P.

2011-01-01

Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (∼106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

Multi-Objective Online Initialization of Spacecraft Formations

NASA Technical Reports Server (NTRS)

Jeffrey, Matthew; Breger, Louis; How, Jonathan P.

2007-01-01

This paper extends a previously developed method for finding spacecraft initial conditions (ICs) that minimize the drift resulting from J2 disturbances while also minimizing the fuel required to attain those ICs. It generalizes the single spacecraft optimization to a formation-wide optimization valid for an arbitrary number of vehicles. Additionally, the desired locations of the spacecraft, separate from the starting location, can be specified, either with respect to a reference orbit, or relative to the other spacecraft in the formation. The three objectives (minimize drift, minimize fuel, and maintain a geometric template) are expressed as competing costs in a linear optimization, and are traded against one another through the use of scalar weights. By carefully selecting these weights and re-initializing the formation at regular intervals, a closed-loop, formation-wide control system is created. This control system can be used to reconfigure the formations on the fly, and creates fuel-efficient plans by placing the spacecraft in semi-invariant orbits. The overall approach is demonstrated through nonlinear simulations for two formations a GEO orbit, and an elliptical orbit.

Networks for Autonomous Formation Flying Satellite Systems

NASA Technical Reports Server (NTRS)

Knoblock, Eric J.; Konangi, Vijay K.; Wallett, Thomas M.; Bhasin, Kul B.

2001-01-01

The performance of three communications networks to support autonomous multi-spacecraft formation flying systems is presented. All systems are comprised of a ten-satellite formation arranged in a star topology, with one of the satellites designated as the central or "mother ship." All data is routed through the mother ship to the terrestrial network. The first system uses a TCP/lP over ATM protocol architecture within the formation the second system uses the IEEE 802.11 protocol architecture within the formation and the last system uses both of the previous architectures with a constellation of geosynchronous satellites serving as an intermediate point-of-contact between the formation and the terrestrial network. The simulations consist of file transfers using either the File Transfer Protocol (FTP) or the Simple Automatic File Exchange (SAFE) Protocol. The results compare the IF queuing delay, and IP processing delay at the mother ship as well as application-level round-trip time for both systems, In all cases, using IEEE 802.11 within the formation yields less delay. Also, the throughput exhibited by SAFE is better than FTP.

Interoperability format translation and transformation between IFC architectural design file and simulation file formats

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

Chao, Tian-Jy; Kim, Younghun

Automatically translating a building architecture file format (Industry Foundation Class) to a simulation file, in one aspect, may extract data and metadata used by a target simulation tool from a building architecture file. Interoperability data objects may be created and the extracted data is stored in the interoperability data objects. A model translation procedure may be prepared to identify a mapping from a Model View Definition to a translation and transformation function. The extracted data may be transformed using the data stored in the interoperability data objects, an input Model View Definition template, and the translation and transformation function tomore » convert the extracted data to correct geometric values needed for a target simulation file format used by the target simulation tool. The simulation file in the target simulation file format may be generated.« less

Teaching Letter Formation.

ERIC Educational Resources Information Center

Graham, Steve; Madan, Avi J.

1981-01-01

The authors describe a remedial technique for teaching letter formation to students with handwriting difficulties. The approach blends traditional procedures (modeling, physical prompts, tracing, self correction, etc.) with cognitive behavior modification principles. (CL)

Formation Control for the Maxim Mission.

NASA Technical Reports Server (NTRS)

Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

2004-01-01

Over the next twenty years, a wave of change is occurring in the spacebased scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today's technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. The Stellar Imager mission requirements are on the same order of those for MAXIM. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; (2) the formation control architecture devised for such missions; (3) the design of the formation control laws to maintain very high precision relative positions; and (4) the levels of fuel usage required in the duration of these missions. Specific preliminary results are presented for two spacecraft within the MAXIM mission.

In situ chemical stimulation of diatomite formations

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

Davis, B.W.

1989-05-09

A method is described of recovering hydrocarbon from a subsurface diatomite formation comprising the steps of: a. introducing an aqueous surface solution into the diatomite formation, the aqueous surface active solution comprising (i) a diatomite/oil/ water wettability improving agent, and (ii) an oil/water interfacial tension lowering agent; and b. producing oil from the diatomite formation.

Radiation pressure in super star cluster formation

NASA Astrophysics Data System (ADS)

Tsang, Benny T.-H.; Milosavljević, Miloš

2018-05-01

The physics of star formation at its extreme, in the nuclei of the densest and the most massive star clusters in the universe—potential massive black hole nurseries—has for decades eluded scrutiny. Spectroscopy of these systems has been scarce, whereas theoretical arguments suggest that radiation pressure on dust grains somehow inhibits star formation. Here, we harness an accelerated Monte Carlo radiation transport scheme to report a radiation hydrodynamical simulation of super star cluster formation in turbulent clouds. We find that radiation pressure reduces the global star formation efficiency by 30-35%, and the star formation rate by 15-50%, both relative to a radiation-free control run. Overall, radiation pressure does not terminate the gas supply for star formation and the final stellar mass of the most massive cluster is ˜1.3 × 106 M⊙. The limited impact as compared to in idealized theoretical models is attributed to a radiation-matter anti-correlation in the supersonically turbulent, gravitationally collapsing medium. In isolated regions outside massive clusters, where the gas distribution is less disturbed, radiation pressure is more effective in limiting star formation. The resulting stellar density at the cluster core is ≥108 M⊙ pc-3, with stellar velocity dispersion ≳ 70 km s-1. We conclude that the super star cluster nucleus is propitious to the formation of very massive stars via dynamical core collapse and stellar merging. We speculate that the very massive star may avoid the claimed catastrophic mass loss by continuing to accrete dense gas condensing from a gravitationally-confined ionized phase.

Media depictions of health topics: challenge and stigma formats.

PubMed

Smith, Rachel

2007-01-01

This article explored the notion that media depictions of health concerns come in one of two formats: challenge and stigma. After explicating the five features that should appear in challenge format and the seven features of stigma formats, we analyzed the content of health messages in magazines, brochures, and posters (n = 75) in a metropolitan area. The results of a two-factor confirmatory factor model showed that the five suggested features for challenge formats did, indeed, appear together (alpha = .76), and the seven features for stigma formats, also, appeared together (alpha = .90), and showed no residual relationship. In other words, the results suggest that media depictions of health topics appear in either challenge or stigma formats (r = - .87). Health issues appearing in magazine advertisements and articles presented messages in challenge formats, while brochures and posters from largely nonprofit and government groups depicted health issues in stigma formats. Some health topics appeared most often in challenge formats (including cancer, heart disease, and scoliosis), while others appeared in stigma formats (including tuberculosis, hepatitis, smoking, and sexually transmitted diseases [STDs]). Findings suggest that media depictions of health differ, and the implications of stigma and challenge formats are discussed.

Relative navigation for spacecraft formation flying

NASA Technical Reports Server (NTRS)

Hartman, Kate R.; Gramling, Cheryl J.; Lee, Taesul; Kelbel, David A.; Long, Anne C.

1998-01-01

The Goddard Space Flight Center Guidance, Navigation, and Control Center (GNCC) is currently developing and implementing advanced satellite systems to provide autonomous control of formation flyers. The initial formation maintenance capability will be flight-demonstrated on the Earth-Orbiter-1 (EO-1) satellite, which is planned under the National Aeronautics and Space Administration New Millennium Program to be a coflight with the Landsat-7 (L-7) satellite. Formation flying imposes relative navigation accuracy requirements in addition to the orbit accuracy requirements for the individual satellites. In the case of EO-1 and L-7, the two satellites are in nearly coplanar orbits, with a small difference in the longitude of the ascending node to compensate for the Earth's rotation. The GNCC has performed trajectory error analysis for the relative navigation of the EO-1/L-7 formation, as well as for a more advanced tracking configuration using cross-link satellite communications. This paper discusses the orbit determination and prediction accuracy achievable for EO-1 and L-7 under various tracking and orbit determination scenarios and discusses the expected relative separation errors in their formation flying configuration.

Relative Navigation for Spacecraft Formation Flying

NASA Technical Reports Server (NTRS)

Hartman, Kate R.; Gramling, Cheryl J.; Lee, Taesul; Kelbel, David A.; Long, Anne C.

1998-01-01

The Goddard Space Flight Center Guidance, Navigation, and Control Center (GNCC) is currently developing and implementing advanced satellite systems to provide autonomous control of formation flyers. The initial formation maintenance capability will be flight-demonstrated on the Earth-Orbiter-1 (EO-l) satellite, which is planned under the National Aeronautics and Space Administration New Millennium Program to be a coflight with the Landsat-7 (L-7) satellite. Formation flying imposes relative navigation accuracy requirements in addition to the orbit accuracy requirements for the individual satellites. In the case of EO-1 and L-7, the two satellites are in nearly coplanar orbits, with a small difference in the longitude of the ascending node to compensate for the Earth's rotation. The GNCC has performed trajectory error analysis for the relative navigation of the EO-1/L-7 formation, as well as for a more advanced tracking configuration using cross- link satellite communications. This paper discusses the orbit determination and prediction accuracy achievable for EO-1 and L-7 under various tracking and orbit determination scenarios and discusses the expected relative separation errors in their formation flying configuration.

Chromatin Ring Formation at Plant Centromeres.

PubMed

Schubert, Veit; Ruban, Alevtina; Houben, Andreas

2016-01-01

We observed the formation of chromatin ring structures at centromeres of somatic rye and Arabidopsis chromosomes. To test whether this behavior is present also in other plant species and tissues we analyzed Arabidopsis, rye, wheat, Aegilops and barley centromeres during cell divisions and in interphase nuclei by immunostaining and FISH. Furthermore, structured illumination microscopy (super-resolution) was applied to investigate the ultrastructure of centromere chromatin beyond the classical refraction limit of light. It became obvious, that a ring formation at centromeres may appear during mitosis, meiosis and in interphase nuclei in all species analyzed. However, varying centromere structures, as ring formations or globular organized chromatin fibers, were identified in different tissues of one and the same species. In addition, we found that a chromatin ring formation may also be caused by subtelomeric repeats in barley. Thus, we conclude that the formation of chromatin rings may appear in different plant species and tissues, but that it is not specific for centromere function. Based on our findings we established a model describing the ultrastructure of plant centromeres and discuss it in comparison to previous models proposed for animals and plants.

Chromatin Ring Formation at Plant Centromeres

PubMed Central

Schubert, Veit; Ruban, Alevtina; Houben, Andreas

2016-01-01

We observed the formation of chromatin ring structures at centromeres of somatic rye and Arabidopsis chromosomes. To test whether this behavior is present also in other plant species and tissues we analyzed Arabidopsis, rye, wheat, Aegilops and barley centromeres during cell divisions and in interphase nuclei by immunostaining and FISH. Furthermore, structured illumination microscopy (super-resolution) was applied to investigate the ultrastructure of centromere chromatin beyond the classical refraction limit of light. It became obvious, that a ring formation at centromeres may appear during mitosis, meiosis and in interphase nuclei in all species analyzed. However, varying centromere structures, as ring formations or globular organized chromatin fibers, were identified in different tissues of one and the same species. In addition, we found that a chromatin ring formation may also be caused by subtelomeric repeats in barley. Thus, we conclude that the formation of chromatin rings may appear in different plant species and tissues, but that it is not specific for centromere function. Based on our findings we established a model describing the ultrastructure of plant centromeres and discuss it in comparison to previous models proposed for animals and plants. PMID:26913037

Reconfigurable Software for Controlling Formation Flying

NASA Technical Reports Server (NTRS)

Mueller, Joseph B.

2006-01-01

Software for a system to control the trajectories of multiple spacecraft flying in formation is being developed to reflect underlying concepts of (1) a decentralized approach to guidance and control and (2) reconfigurability of the control system, including reconfigurability of the software and of control laws. The software is organized as a modular network of software tasks. The computational load for both determining relative trajectories and planning maneuvers is shared equally among all spacecraft in a cluster. The flexibility and robustness of the software are apparent in the fact that tasks can be added, removed, or replaced during flight. In a computational simulation of a representative formation-flying scenario, it was demonstrated that the following are among the services performed by the software: Uploading of commands from a ground station and distribution of the commands among the spacecraft, Autonomous initiation and reconfiguration of formations, Autonomous formation of teams through negotiations among the spacecraft, Working out details of high-level commands (e.g., shapes and sizes of geometrically complex formations), Implementation of a distributed guidance law providing autonomous optimization and assignment of target states, and Implementation of a decentralized, fuel-optimal, impulsive control law for planning maneuvers.

Fusomorphogenesis: cell fusion in organ formation.

PubMed

Shemer, G; Podbilewicz, B

2000-05-01

Cell fusion is a universal process that occurs during fertilization and in the formation of organs such as muscles, placenta, and bones. Very little is known about the molecular and cellular mechanisms of cell fusion during pattern formation. Here we review the dynamic anatomy of all cell fusions during embryonic and postembryonic development in an organism. Nearly all the cell fates and cell lineages are invariant in the nematode C. elegans and one third of the cells that are born fuse to form 44 syncytia in a reproducible and stereotyped way. To explain the function of cell fusion in organ formation we propose the fusomorphogenetic model as a simple cellular mechanism to efficiently redistribute membranes using a combination of cell fusion and polarized membrane recycling during morphogenesis. Thus, regulated intercellular and intracellular membrane fusion processes may drive elongation of the embryo as well as postembryonic organ formation in C. elegans. Finally, we use the fusomorphogenetic hypothesis to explain the role of cell fusion in the formation of organs like muscles, bones, and placenta in mammals and other species and to speculate on how the intracellular machinery that drive fusomorphogenesis may have evolved.

LANDSAT-D data format control book. Volume 2: Telemetry

NASA Technical Reports Server (NTRS)

Talipsky, R.

1982-01-01

The formats used for the transmission of LANDSAT-D and LANDSAT-D Prime spacecraft telemetry data through either the TDRS/GSTDN via the NASCOM Network to the CSF are described as well as the telemetry flow from the command and data handling subsystem, a telemetry list and telemetry matrix assignment for the mission and engineering formats. The on-board computer (OBC) controlled format and the dwell format are also discussed. The OBCs contribution to telemetry, and the format of the reports, are covered. The high rate data channel includes the payload correction data format, the narrowband tape recorder and the OBC dump formats.

Parallax Player: a stereoscopic format converter

NASA Astrophysics Data System (ADS)

Feldman, Mark H.; Lipton, Lenny

2003-05-01

The Parallax Player is a software application that is, in essence, a stereoscopic format converter. Various formats may be inputted and outputted. In addition to being able to take any one of a wide variety of different formats and play them back on many different kinds of PCs and display screens. The Parallax Player has built into it the capability to produce ersatz stereo from a planar still or movie image. The player handles two basic forms of digital content - still images, and movies. It is assumed that all data is digital, either created by means of a photographic film process and later digitized, or directly captured or authored in a digital form. In its current implementation, running on a number of Windows Operating Systems, The Parallax Player reads in a broad selection of contemporary file formats.

Written formative assessment and silence in the classroom

NASA Astrophysics Data System (ADS)

Lee Hang, Desmond Mene; Bell, Beverley

2015-09-01

In this commentary, we build on Xinying Yin and Gayle Buck's discussion by exploring the cultural practices which are integral to formative assessment, when it is viewed as a sociocultural practice. First we discuss the role of assessment and in particular oral and written formative assessments in both western and Samoan cultures, building on the account of assessment practices in the Chinese culture given by Yin and Buck. Secondly, we document the cultural practice of silence in Samoan classroom's which has lead to the use of written formative assessment as in the Yin and Buck article. We also discuss the use of written formative assessment as a scaffold for teacher development for formative assessment. Finally, we briefly discuss both studies on formative assessment as a sociocultural practice.

The Center for Star Formation Studies

NASA Technical Reports Server (NTRS)

Hollenbach, D.; Bell, K. R.; Laughlin, G.

2002-01-01

The Center for Star Formation Studies, a consortium of scientists from the Space Science Division at Ames and the Astronomy Departments of the University of California at Berkeley and Santa Cruz, conducts a coordinated program of theoretical research on star and planet formation. Under the directorship of D. Hollenbach (Ames), the Center supports postdoctoral fellows, senior visitors, and students; meets regularly at Ames to exchange ideas and to present informal seminars on current research; hosts visits of outside scientists; and conducts a week-long workshop on selected aspects of star and planet formation each summer.

Formation Control over Delayed Communication Network

NASA Astrophysics Data System (ADS)

Secchi, Cristian; Fantuzzi, Cesare

In this Chapter we address the problem of formation control of a group of robots that exchange information over a communication network characterized by a non negligible delay. We consider the Virtual Body Artificial Potential approach for stabilizing a group of robots at a desired formation. We show that it is possible to model the controlled group of robots as a port-Hamiltonian system and we exploit the scattering framework to achieve a passive behavior of the controlled system and to stabilize the robots in the desired formation independently of any communication delay.

Revision of middle Proterozoic Yellowjacket Formation, central Idaho, and revision of Cretaceous Slim Sam Formation, Elkhorn mountains area, Montana

USGS Publications Warehouse

Tysdal, Russell G.

2000-01-01

The Yellowjacket Formation is restricted to the strata originally assigned to it by Ross (1934). The Yellowjacket, the conformably overlying Hoodoo Quartzite, and succeeding unnamed argillaceous quartzite unit form a genetically related sequence that lies in a structural block delimited on the northeast by the Iron Lake fault. Directly northeast of the fault, strata currently assigned by others to the lower subunit of the Yellowjacket are correlated with the Apple Creek Formation in the Lemhi Range. Mapping in the western part of the Lemhi Range shows that the Apple Creek Formation lies depositionally above the Big Creek Formation and that no rocks of the Yellowjacket-Hoodoo unnamed unit stratigraphic sequence are present. In contrast, in the area of the Yellowjacket mapped by Ross (1934) and the area directly northeast of the Iron Lake Fault, the Big Creek Formation is absent, even though it is 2,700 m thick in the Lemhi Range. These data indicate that the Iron Lake Fault juxtaposed the Yellowjacket-Hoodoo-unnamed unit sequence against non-Yellowjacket strata to the northeast. The Upper Cretaceous Slim Sam Formation of the Elkhorn Mountains area is revised. Strata of the lower part are correlated with the regionally recognized marine Telegraph Creek Formation and the overlying marine to marginal marine Eagle Sandstone. Only lower strata of the Eagle are present in the study area and they are preserved discontinously. The nonmarine volcanic and volcaniclastic rocks of the upper part of the Slim Sam as originally defined retain the name Slim Sam Formation. These rocks, mainly of sedimentary origin, are genetically related to the Elkhorn Mountains Volcanics. The lower contact of the Slim Sam (restricted) is unconformable above the Eagle Sandstone or more commonly above the Telegraph Creek Formation. The upper contact is conformable with the Elkhorn Mountains Volcanics.

Formate: an Energy Storage and Transport Bridge between Carbon Dioxide and a Formate Fuel Cell in a Single Device.

PubMed

Vo, Tracy; Purohit, Krutarth; Nguyen, Christopher; Biggs, Brenna; Mayoral, Salvador; Haan, John L

2015-11-01

We demonstrate the first device to our knowledge that uses a solar panel to power the electrochemical reduction of dissolved carbon dioxide (carbonate) into formate that is then used in the same device to operate a direct formate fuel cell (DFFC). The electrochemical reduction of carbonate is carried out on a Sn electrode in a reservoir that maintains a constant carbon balance between carbonate and formate. The electron-rich formate species is converted by the DFFC into electrical energy through electron release. The product of DFFC operation is the electron-deficient carbonate species that diffuses back to the reservoir bulk. It is possible to continuously charge the device using alternative energy (e.g., solar) to convert carbonate to formate for on-demand use in the DFFC; the intermittent nature of alternative energy makes this an attractive design. In this work, we demonstrate a proof-of-concept device that performs reduction of carbonate, storage of formate, and operation of a DFFC. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Review of nutrition labeling formats.

PubMed

Geiger, C J; Wyse, B W; Parent, C R; Hansen, R G

1991-07-01

This article examines nutrition labeling history as well as the findings of nine research studies of nutrition labeling formats. Nutrition labeling regulations were announced in 1973 and have been periodically amended since then. In response to requests from consumers and health care professionals for revision of the labeling system, the Food and Drug Administration initiated a three-phase plan for reform of nutrition labeling in 1990. President Bush signed the Nutrition Labeling and Education Act in November 1990. Literature analysis revealed that only nine studies with an experimental design have focused on nutrition labeling since 1971. Four were conducted before 1975, which was the year that nutrition labeling was officially implemented, two were conducted in 1980, and three were conducted after 1986. Only two of the nine studies supported the traditional label format mandated by the Code of Federal Regulations, and one study partially supported it. Four of the nine studies that evaluated graphic presentations of nutrition information found that consumer comprehension of nutrition information was improved with a graphic format for nutrition labeling: three studies supported the use of bar graphs and one study supported the use of a pie chart. Full disclosure (ie, complete nutrient and ingredient labeling) was preferred by consumers in two of the three studies that examined this variable. The third study supported three types of information disclosure dependent upon socioeconomic class. In those studies that tested graphics, a bar graph format was significantly preferred and showed better consumer comprehension than the traditional format.

Modulation format identification aided hitless flexible coherent transceiver.

PubMed

Xiang, Meng; Zhuge, Qunbi; Qiu, Meng; Zhou, Xingyu; Zhang, Fangyuan; Tang, Ming; Liu, Deming; Fu, Songnian; Plant, David V

2016-07-11

We propose a hitless flexible coherent transceiver enabled by a novel modulation format identification (MFI) scheme for dynamic agile optical networks. The modulation format transparent digital signal processing (DSP) is realized by a block-wise decision-directed least-mean-square (DD-LMS) equalizer for channel tracking, and a pilot symbol aided superscalar phase locked loop (PLL) for carrier phase estimation (CPE). For the MFI, the modulation format information is encoded onto the pilot symbols initially used for CPE. Therefore, the proposed MFI method does not require extra overhead. Moreover, it can identify arbitrary modulation formats including multi-dimensional formats, and it enables tracking of the format change for short data blocks. The performance of the proposed hitless flexible coherent transceiver is successfully evaluated with five modulation formats including QPSK, 16QAM, 64QAM, Hybrid QPSK/8QAM and set-partitioning (SP)-512-QAM. We show that the proposed MFI method induces a negligible performance penalty. Moreover, we experimentally demonstrate that such a hitless transceiver can adapt to fast block-by-block modulation format switching. Finally, the performance improvement of the proposed MFI method is experimentally verified with respect to other commonly used MFI methods.

Bibliography of Leishmania and Leishmanial Diseases. Volume 2

DTIC Science & Technology

1980-08-01

sclintifica no ’Rio Parana’ a Assuni nutrition des trypanoaomides. Ann. dlon com volta, por Buenos Aires, Inst. Pasteur Paris, 51(I)t55_Ii6. Montevideo e Rio...de synthose des eishmanies, c. R. S’nc, Soc., -------------------- (1932A) Recherche* biochimiques Biol. , 130:406-408. sur la nutrition des...1934A) Die Bedeutung des (1051A) The nutrition of pers- B*iutT;srbtoftes Nir die parastischen oitic flagellates,(Trypanosomidso, Tri- chom0onadinae. Ln

Brazil wheat yield covariance model

NASA Technical Reports Server (NTRS)

Callis, S. L.; Sakamoto, C.

1984-01-01

A model based on multiple regression was developed to estimate wheat yields for the wheat growing states of Rio Grande do Sul, Parana, and Santa Catarina in Brazil. The meteorological data of these three states were pooled and the years 1972 to 1979 were used to develop the model since there was no technological trend in the yields during these years. Predictor variables were derived from monthly total precipitation, average monthly mean temperature, and average monthly maximum temperature.

Making Moves: Formative Assessment in Mathematics

ERIC Educational Resources Information Center

Duckor, Brent; Holmberg, Carrie; Becker, Joanne Rossi

2017-01-01

Research on teacher professional learning has shown that formative assessment can improve student learning more than most instructional practices. Empirical evidence indicates that thoughtfully implemented formative assessment practices improve students' learning, increase students' scores, and narrow achievement gaps between low-achieving…

Dark-ages reionization and galaxy formation simulation - III. Modelling galaxy formation and the epoch of reionization

NASA Astrophysics Data System (ADS)

Mutch, Simon J.; Geil, Paul M.; Poole, Gregory B.; Angel, Paul W.; Duffy, Alan R.; Mesinger, Andrei; Wyithe, J. Stuart B.

2016-10-01

We introduce MERAXES, a new, purpose-built semi-analytic galaxy formation model designed for studying galaxy growth during reionization. MERAXES is the first model of its type to include a temporally and spatially coupled treatment of reionization and is built upon a custom (100 Mpc)3 N-body simulation with high temporal and mass resolution, allowing us to resolve the galaxy and star formation physics relevant to early galaxy formation. Our fiducial model with supernova feedback reproduces the observed optical depth to electron scattering and evolution of the galaxy stellar mass function between z = 5 and 7, predicting that a broad range of halo masses contribute to reionization. Using a constant escape fraction and global recombination rate, our model is unable to simultaneously match the observed ionizing emissivity at z ≲ 6. However, the use of an evolving escape fraction of 0.05-0.1 at z ˜ 6, increasing towards higher redshift, is able to satisfy these three constraints. We also demonstrate that photoionization suppression of low-mass galaxy formation during reionization has only a small effect on the ionization history of the intergalactic medium. This lack of `self-regulation' arises due to the already efficient quenching of star formation by supernova feedback. It is only in models with gas supply-limited star formation that reionization feedback is effective at regulating galaxy growth. We similarly find that reionization has only a small effect on the stellar mass function, with no observationally detectable imprint at M* > 107.5 M⊙. However, patchy reionization has significant effects on individual galaxy masses, with variations of factors of 2-3 at z = 5 that correlate with environment.

The Impact Of Galactic Environment On Star Formation

NASA Astrophysics Data System (ADS)

Kreckel, Kathryn

2016-09-01

While spiral arms are the most prominent sites for star formation in disk galaxies, interarm star formation contributes significantly to the overall star formation budget. However, it is still an open question if the star formation proceeds differently in the arm and inter-arm environment. We use deep VLT/MUSE optical IFU spectroscopy to resolve and fully characterize the physical properties of 428 interarm and arm HII regions in the nearby grand design spiral galaxy NGC 628. Unlike molecular clouds (the fuel for star formation) which exhibit a clear dependence on galactic environment, we find that most HII region properties (luminosity, size, metallicity, ionization parameter) are independent of environment. One clear exception is the diffuse ionized gas (DIG) contribution to the arm and interarm flux (traced via the temperature sensitive [SII]/Halpha line ratio inside and outside of the HII region boundaries). We find a systematically higher DIG background within HII regions, particularly on the spiral arms. Correcting for this DIG contamination can result in significant (70%) changes to the star formation rate measured. We also show preliminary results comparing well@corrected star formation rates from our MUSE HII regions to ALMA CO(2-1) molecular gas observations at matched 1"=35pc resolution, tracing the Kennicutt-Schmidt star formation law at the scales relevant to the physics of star formation. We estimate the timescales relevant for GMC evolution using distance from the spiral arm as a proxy for age, and test whether star formation feedback or galactic@scale dynamical processes dominate GMC disruption.

The impact of galactic environment on star formation

NASA Astrophysics Data System (ADS)

Kreckel, Kathryn; Blanc, Guillermo A.; Schinnerer, Eva; Groves, Brent; Adamo, Angela; Hughes, Annie; Meidt, Sharon; SFNG Collaboration

2017-01-01

While spiral arms are the most prominent sites for star formation in disk galaxies, interarm star formation contributes significantly to the overall star formation budget. However, it is still an open question if the star formation proceeds differently in the arm and inter-arm environment. We use deep VLT/MUSE optical IFU spectroscopy to resolve and fully characterize the physical properties of 428 interarm and arm HII regions in the nearby grand design spiral galaxy NGC 628. Unlike molecular clouds (the fuel for star formation) which exhibit a clear dependence on galactic environment, we find that most HII region properties (luminosity, size, metallicity, ionization parameter) are independent of environment. One clear exception is the diffuse ionized gas (DIG) contribution to the arm and interarm flux (traced via the temperature sensitive [SII]/Halpha line ratio inside and outside of the HII region boundaries). We find a systematically higher DIG background within HII regions, particularly on the spiral arms. Correcting for this DIG contamination can result in significant (70%) changes to the star formation rate measured. We also show preliminary results comparing well-corrected star formation rates from our MUSE HII regions to ALMA CO(2-1) molecular gas observations at matched 1"=50pc resolution, tracing the Kennicutt-Schmidt star formation law at the scales relevant to the physics of star formation. We estimate the timescales relevant for GMC evolution using distance from the spiral arm as a proxy for age, and test whether star formation feedback or galactic-scale dynamical processes dominate GMC disruption.

Chaetomium thermophilum formate dehydrogenase has high activity in the reduction of hydrogen carbonate (HCO3 -) to formate.

PubMed

Aslan, Aşkın Sevinç; Valjakka, Jarkko; Ruupunen, Jouni; Yildirim, Deniz; Turner, Nicholas J; Turunen, Ossi; Binay, Barış

2017-01-01

While formate dehydrogenases (FDHs) have been used for cofactor recycling in chemoenzymatic synthesis, the ability of FDH to reduce CO 2 could also be utilized in the conversion of CO 2 to useful products via formate (HCOO - ). In this study, we investigated the reduction of CO 2 in the form of hydrogen carbonate (HCO 3 - ) to formate by FDHs from Candida methylica (CmFDH) and Chaetomium thermophilum (CtFDH) in a NADH-dependent reaction. The catalytic performance with HCO 3 - as a substrate was evaluated by measuring the kinetic rates and conducting productivity assays. CtFDH showed a higher efficiency in converting HCO 3 - to formate than CmFDH, whereas CmFDH was better in the oxidation of formate. The pH optimum of the reduction was at pH 7-8. However, the high concentrations of HCO 3 - reduced the reaction rate. CtFDH was modeled in the presence of HCO 3 - showing that it fits to the active site. The active site setting for hydride transfer in CO 2 reduction was modeled. The hydride donated by NADH would form a favorable contact to the carbon atom of HCO 3 - , resulting in a surplus of electrons within the molecule. This would cause the complex formed by hydrogen carbonate and the hydride to break into formate and hydroxide ions. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[Calculi formation and biliary hydrodynamics].

PubMed

Zou, S Q

1990-09-01

In this study, 167 white rabbits were divided into 5 groups to observe the effects of biliary stricture and infection on the formation of bile duct stones and the pathophysiological changes of the biliary tract. It was found that there was a gradient of static hydraulic pressure along biliary tract and the pressure was directly proportional to hepatic blood flow. In the rabbits with bile duct stone formation, the activity of SDH, ATP ase and glycogen (PAS) in the mucosa of biliary tract was low and that of LDH was high. In the biliary tract wall damaged by infection and choledocholithiasis, a frame work consisting of polysaccharide protein, mucin, and mucoid polymer was observed and the authors considered it as one of causing factors in the formation of the stones.

Spatial competition and price formation

NASA Astrophysics Data System (ADS)

Nagel, Kai; Shubik, Martin; Paczuski, Maya; Bak, Per

2000-12-01

We look at price formation in a retail setting, that is, companies set prices, and consumers either accept prices or go someplace else. In contrast to most other models in this context, we use a two-dimensional spatial structure for information transmission, that is, consumers can only learn from nearest neighbors. Many aspects of this can be understood in terms of generalized evolutionary dynamics. In consequence, we first look at spatial competition and cluster formation without price. This leads to establishement size distributions, which we compare to reality. After some theoretical considerations, which at least heuristically explain our simulation results, we finally return to price formation, where we demonstrate that our simple model with nearly no organized planning or rationality on the part of any of the agents indeed leads to an economically plausible price.

Exploring Formative Assessment as a Tool for Learning: Students' Experiences of Different Methods of Formative Assessment

ERIC Educational Resources Information Center

Weurlander, Maria; Soderberg, Magnus; Scheja, Max; Hult, Hakan; Wernerson, Annika

2012-01-01

This study aims to provide a greater insight into how formative assessments are experienced and understood by students. Two different formative assessment methods, an individual, written assessment and an oral group assessment, were components of a pathology course within a medical curriculum. In a cohort of 70 students, written accounts were…

Sensitivity Data File Formats

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

Rearden, Bradley T.

2016-04-01

The format of the TSUNAMI-A sensitivity data file produced by SAMS for cases with deterministic transport solutions is given in Table 6.3.A.1. The occurrence of each entry in the data file is followed by an identification of the data contained on each line of the file and the FORTRAN edit descriptor denoting the format of each line. A brief description of each line is also presented. A sample of the TSUNAMI-A data file for the Flattop-25 sample problem is provided in Figure 6.3.A.1. Here, only two profiles out of the 130 computed are shown.

Formation and dissolution of bacterial colonies.

PubMed

Weber, Christoph A; Lin, Yen Ting; Biais, Nicolas; Zaburdaev, Vasily

2015-09-01

Many organisms form colonies for a transient period of time to withstand environmental pressure. Bacterial biofilms are a prototypical example of such behavior. Despite significant interest across disciplines, physical mechanisms governing the formation and dissolution of bacterial colonies are still poorly understood. Starting from a kinetic description of motile and interacting cells we derive a hydrodynamic equation for their density on a surface, where most of the kinetic coefficients are estimated from experimental data for N. gonorrhoeae bacteria. We use it to describe the formation of multiple colonies with sizes consistent with experimental observations. Finally, we show how the changes in the cell-to-cell interactions lead to the dissolution of the bacterial colonies. The successful application of kinetic theory to a complex far from equilibrium system such as formation and dissolution of living bacterial colonies potentially paves the way for the physical quantification of the initial stages of biofilm formation.

Environmental factors that shape biofilm formation.

PubMed

Toyofuku, Masanori; Inaba, Tomohiro; Kiyokawa, Tatsunori; Obana, Nozomu; Yawata, Yutaka; Nomura, Nobuhiko

2016-01-01

Cells respond to the environment and alter gene expression. Recent studies have revealed the social aspects of bacterial life, such as biofilm formation. Biofilm formation is largely affected by the environment, and the mechanisms by which the gene expression of individual cells affects biofilm development have attracted interest. Environmental factors determine the cell's decision to form or leave a biofilm. In addition, the biofilm structure largely depends on the environment, implying that biofilms are shaped to adapt to local conditions. Second messengers such as cAMP and c-di-GMP are key factors that link environmental factors with gene regulation. Cell-to-cell communication is also an important factor in shaping the biofilm. In this short review, we will introduce the basics of biofilm formation and further discuss environmental factors that shape biofilm formation. Finally, the state-of-the-art tools that allow us investigate biofilms under various conditions are discussed.

Reaction mechanism of molybdoenzyme formate dehydrogenase.

PubMed

Leopoldini, Monica; Chiodo, Sandro G; Toscano, Marirosa; Russo, Nino

2008-01-01

Formate dehydrogenase is a molybdoenzyme of the anaerobic formate hydrogen lyase complex of the Escherichia coli microorganism that catalyzes the oxidation of formate to carbon dioxide. The two proposed mechanisms of reaction, which differ in the occurrence of a direct coordination or not of a SeCys residue to the molybdenum metal during catalysis were analyzed at the density functional level in both vacuum and protein environments. Some DF functionals, in addition to the very popular B3LYP one, were employed to compute barrier heights. Results revealed the role played by the SeCys residue in performing the abstraction of the proton from the formate substrate. The computation of the energetic profiles for both mechanisms indicated that the reaction barriers are higher when the selenium is directly coordinated to the metal, whereas less energy is required when SeCys is not a ligand at the molybdenum site.

Right timing in formative program evaluation.

PubMed

Hall, Jori; Freeman, Melissa; Roulston, Kathy

2014-08-01

Since many educational researchers and program developers have limited knowledge of formative evaluation, formative data may be underutilized during the development and implementation of an educational program. The purpose of this article is to explain how participatory, responsive, educative, and qualitative approaches to formative evaluation can facilitate a partnership between evaluators and educational researchers and program managers to generate data useful to inform program implementation and improvement. This partnership is critical, we argue, because it enables an awareness of when to take appropriate action to ensure successful educational programs or "kairos". To illustrate, we use examples from our own evaluation work to highlight how formative evaluation may facilitate opportune moments to (1) define the substance and purpose of a program, (2) develop understanding and awareness of the cultural interpretations of program participants, and (3) show the relevance of stakeholder experiences to program goals. Copyright © 2014 Elsevier Ltd. All rights reserved.

The df: A proposed data format standard

NASA Technical Reports Server (NTRS)

Lait, Leslie R.; Nash, Eric R.; Newman, Paul A.

1993-01-01

A standard is proposed describing a portable format for electronic exchange of data in the physical sciences. Writing scientific data in a standard format has three basic advantages: portability; the ability to use metadata to aid in interpretation of the data (understandability); and reusability. An improperly formulated standard format tends towards four disadvantages: (1) it can be inflexible and fail to allow the user to express his data as needed; (2) reading and writing such datasets can involve high overhead in computing time and storage space; (3) the format may be accessible only on certain machines using certain languages; and (4) under some circumstances it may be uncertain whether a given dataset actually conforms to the standard. A format was designed which enhances these advantages and lessens the disadvantages. The fundamental approach is to allow the user to make her own choices regarding strategic tradeoffs to achieve the performance desired in her local environment. The choices made are encoded in a specific and portable way in a set of records. A fully detailed description and specification of the format is given, and examples are used to illustrate various concepts. Implementation is discussed.

Adolescent Violent Victimization and Precocious Union Formation.

PubMed

C Kuhl, Danielle; Warner, David F; Wilczak, Andrew

2012-11-01

This article bridges scholarship in criminology and family sociology by extending arguments about "precocious exits" from adolescence to consider early union formation as a salient outcome of violent victimization for youths. Research indicates that early union formation is associated with several negative outcomes; yet the absence of attention to union formation as a consequence of violent victimization is noteworthy. We address this gap by drawing on life course theory and data from the National Longitudinal Study of Adolescent Health (Add Health) to examine the effect of violent victimization ("street" violence) on the timing of first co-residential union formation-differentiating between marriage and cohabitation-in young adulthood. Estimates from Cox proportional hazard models show that adolescent victims of street violence experience higher rates of first union formation, especially marriage, early in the transition to adulthood; however, this effect declines with age, as such unions become more normative. Importantly, the effect of violent victimization on first union timing is robust to controls for nonviolent delinquency, substance abuse, and violent perpetration. We conclude by discussing directions for future research on the association between violent victimization and coresidential unions with an eye toward the implications of such early union formation for desistance.

Network Configuration Analysis for Formation Flying Satellites

NASA Technical Reports Server (NTRS)

Knoblock, Eric J.; Wallett, Thomas M.; Konangi, Vijay K.; Bhasin, Kul B.

2001-01-01

The performance of two networks to support autonomous multi-spacecraft formation flying systems is presented. Both systems are comprised of a ten-satellite formation, with one of the satellites designated as the central or 'mother ship.' All data is routed through the mother ship to the terrestrial network. The first system uses a TCP/EP over ATM protocol architecture within the formation, and the second system uses the IEEE 802.11 protocol architecture within the formation. The simulations consist of file transfers using either the File Transfer Protocol (FTP) or the Simple Automatic File Exchange (SAFE) Protocol. The results compare the IP queuing delay, IP queue size and IP processing delay at the mother ship as well as end-to-end delay for both systems. In all cases, using IEEE 802.11 within the formation yields less delay. Also, the throughput exhibited by SAFE is better than FTP.

Renewable Formate from C-H Bond Formation with CO2: Using Iron Carbonyl Clusters as Electrocatalysts.

PubMed

Loewen, Natalia D; Neelakantan, Taruna V; Berben, Louise A

2017-09-19

As a society, we are heavily dependent on nonrenewable petroleum-derived fuels and chemical feedstocks. Rapid depletion of these resources and the increasingly evident negative effects of excess atmospheric CO 2 drive our efforts to discover ways of converting excess CO 2 into energy dense chemical fuels through selective C-H bond formation and using renewable energy sources to supply electrons. In this way, a carbon-neutral fuel economy might be realized. To develop a molecular or heterogeneous catalyst for C-H bond formation with CO 2 requires a fundamental understanding of how to generate metal hydrides that selectively donate H - to CO 2 , rather than recombining with H + to liberate H 2 . Our work with a unique series of water-soluble and -stable, low-valent iron electrocatalysts offers mechanistic and thermochemical insights into formate production from CO 2 . Of particular interest are the nitride- and carbide-containing clusters: [Fe 4 N(CO) 12 ] - and its derivatives and [Fe 4 C(CO) 12 ] 2- . In both aqueous and mixed solvent conditions, [Fe 4 N(CO) 12 ] - forms a reduced hydride intermediate, [H-Fe 4 N(CO) 12 ] - , through stepwise electron and proton transfers. This hydride selectively reacts with CO 2 and generates formate with >95% efficiency. The mechanism for this transformation is supported by crystallographic, cyclic voltammetry, and spectroelectrochemical (SEC) evidence. Furthermore, installation of a proton shuttle onto [Fe 4 N(CO) 12 ] - facilitates proton transfer to the active site, successfully intercepting the hydride intermediate before it reacts with CO 2 ; only H 2 is observed in this case. In contrast, isoelectronic [Fe 4 C(CO) 12 ] 2- features a concerted proton-electron transfer mechanism to form [H-Fe 4 C(CO) 12 ] 2- , which is selective for H 2 production even in the presence of CO 2 , in both aqueous and mixed solvent systems. Higher nuclearity clusters were also studied, and all are proton reduction electrocatalysts, but none

Simbol-X Formation Flight and Image Reconstruction

NASA Astrophysics Data System (ADS)

Civitani, M.; Djalal, S.; Le Duigou, J. M.; La Marle, O.; Chipaux, R.

2009-05-01

Simbol-X is the first operational mission relying on two satellites flying in formation. The dynamics of the telescope, due to the formation flight concept, raises a variety of problematic, like image reconstruction, that can be better evaluated via a simulation tools. We present here the first results obtained with Simulos, simulation tool aimed to study the relative spacecrafts navigation and the weight of the different parameters in image reconstruction and telescope performance evaluation. The simulation relies on attitude and formation flight sensors models, formation flight dynamics and control, mirror model and focal plane model, while the image reconstruction is based on the Line of Sight (LOS) concept.

Formation of the First Stars and Blackholes

NASA Astrophysics Data System (ADS)

Yoshida, Naoki

2018-05-01

Cosmic reionization is thought to be initiated by the first generation of stars and blackholes. We review recent progress in theoretical studies of early structure formation. Cosmic structure formation is driven by gravitational instability of primeval density fluctuations left over from Big Bang. At early epochs, there are baryonic streaming motions with significant relative velocity with respect to dark matter. The formation of primordial gas clouds is typically delayed by the streaming motions, but then physical conditions for the so-called direct collapse blackhole formation are realized in proto-galactic halos. We present a promising model in which intermediate mass blackholes are formed as early as z = 30.

HOW GALACTIC ENVIRONMENT REGULATES STAR FORMATION

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

Meidt, Sharon E.

2016-02-10

In a new simple model I reconcile two contradictory views on the factors that determine the rate at which molecular clouds form stars—internal structure versus external, environmental influences—providing a unified picture for the regulation of star formation in galaxies. In the presence of external pressure, the pressure gradient set up within a self-gravitating turbulent (isothermal) cloud leads to a non-uniform density distribution. Thus the local environment of a cloud influences its internal structure. In the simple equilibrium model, the fraction of gas at high density in the cloud interior is determined simply by the cloud surface density, which is itselfmore » inherited from the pressure in the immediate surroundings. This idea is tested using measurements of the properties of local clouds, which are found to show remarkable agreement with the simple equilibrium model. The model also naturally predicts the star formation relation observed on cloud scales and at the same time provides a mapping between this relation and the closer-to-linear molecular star formation relation measured on larger scales in galaxies. The key is that pressure regulates not only the molecular content of the ISM but also the cloud surface density. I provide a straightforward prescription for the pressure regulation of star formation that can be directly implemented in numerical models. Predictions for the dense gas fraction and star formation efficiency measured on large-scales within galaxies are also presented, establishing the basis for a new picture of star formation regulated by galactic environment.« less

SCIFIO: an extensible framework to support scientific image formats.

PubMed

Hiner, Mark C; Rueden, Curtis T; Eliceiri, Kevin W

2016-12-07

No gold standard exists in the world of scientific image acquisition; a proliferation of instruments each with its own proprietary data format has made out-of-the-box sharing of that data nearly impossible. In the field of light microscopy, the Bio-Formats library was designed to translate such proprietary data formats to a common, open-source schema, enabling sharing and reproduction of scientific results. While Bio-Formats has proved successful for microscopy images, the greater scientific community was lacking a domain-independent framework for format translation. SCIFIO (SCientific Image Format Input and Output) is presented as a freely available, open-source library unifying the mechanisms of reading and writing image data. The core of SCIFIO is its modular definition of formats, the design of which clearly outlines the components of image I/O to encourage extensibility, facilitated by the dynamic discovery of the SciJava plugin framework. SCIFIO is structured to support coexistence of multiple domain-specific open exchange formats, such as Bio-Formats' OME-TIFF, within a unified environment. SCIFIO is a freely available software library developed to standardize the process of reading and writing scientific image formats.

40 CFR 610.17 - Application format.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Application format. 610.17 Section 610.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria General Provisions § 610.17 Application format. (a...

40 CFR 610.17 - Application format.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Application format. 610.17 Section 610.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria General Provisions § 610.17 Application format. (a...

40 CFR 610.17 - Application format.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Application format. 610.17 Section 610.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria General Provisions § 610.17 Application format. (a...

Star-Formation Histories of MUSCEL Galaxies

NASA Astrophysics Data System (ADS)

Young, Jason; Kuzio de Naray, Rachel; Xuesong Wang, Sharon

2018-01-01

The MUSCEL program (MUltiwavelength observations of the Structure, Chemistry and Evolution of LSB galaxies) uses combined ground-based/space-based data to determine the spatially resolved star-formation histories of low surface brightness (LSB) galaxies. LSB galaxies are paradoxical in that they are gas rich but have low star-formation rates. Here we present our observations and fitting technique, and the derived histories for select MUSCEL galaxies. It is our aim to use these histories in tandem with velocity fields and metallicity profiles to determine the physical mechanism(s) that give these faint galaxies low star-formation rates despite ample gas supplies.

Varying heating in dawsonite zones in hydrocarbon containing formations

DOEpatents

Vinegar, Harold J [Bellaire, TX; Xie, Xueying [Houston, TX; Miller, David Scott [Katy, TX

2009-07-07

A method for treating an oil shale formation comprising dawsonite includes assessing a dawsonite composition of one or more zones in the formation. Heat from one or more heaters is provided to the formation such that different amounts of heat are provided to zones with different dawsonite compositions. The provided heat is allowed to transfer from the heaters to the formation. Fluids are produced from the formation.

Ribbed moraine formation

NASA Astrophysics Data System (ADS)

Hättestrand, Clas; Kleman, Johan

Ribbed (Rogen) moraines are conspicuous landforms found in interior parts of formerly glaciated areas. Two major theories for ribbed moraine formation have been suggested in recent years: (i) the shear and stack theory, which explains ribbed moraine formation by shearing and stacking of till slabs or englacially entrained material during compressive flow, followed by basal melt-out of transverse moraine ridges, and (ii) the fracturing theory, according to which ribbed moraines form by fracturing of frozen pre-existing till sheets, at the transition from cold- to warm-based conditions under deglaciating ice sheets. In this paper, we present new data on the distribution of ribbed moraines and their close association with areas of frozen-bed conditions under ice sheets. In addition, we show examples of ribbed moraine ridges that fit together like a jig-saw puzzle. These observations indicate that fracturing and extension of a pre-existing till sheet may be a predominant process in ribbed moraine formation. In summary, we conclude that all described characteristics of ribbed moraines are compatible with the fracturing theory, while the shear and stack theory is hampered by an inability to explain many conspicuous features in the distribution pattern and detailed morphology of ribbed moraines. One implication of the fracturing theory is that the distribution of ribbed moraines can be used to reconstruct the extent of areas that underwent a change from frozen-bed to thawed-bed conditions under former ice sheets.

The formation of the solar system

NASA Astrophysics Data System (ADS)

Pfalzner, S.; Davies, M. B.; Gounelle, M.; Johansen, A.; Münker, C.; Lacerda, P.; Portegies Zwart, S.; Testi, L.; Trieloff, M.; Veras, D.

2015-06-01

The solar system started to form about 4.56 Gyr ago and despite the long intervening time span, there still exist several clues about its formation. The three major sources for this information are meteorites, the present solar system structure and the planet-forming systems around young stars. In this introduction we give an overview of the current understanding of the solar system formation from all these different research fields. This includes the question of the lifetime of the solar protoplanetary disc, the different stages of planet formation, their duration, and their relative importance. We consider whether meteorite evidence and observations of protoplanetary discs point in the same direction. This will tell us whether our solar system had a typical formation history or an exceptional one. There are also many indications that the solar system formed as part of a star cluster. Here we examine the types of cluster the Sun could have formed in, especially whether its stellar density was at any stage high enough to influence the properties of today’s solar system. The likelihood of identifying siblings of the Sun is discussed. Finally, the possible dynamical evolution of the solar system since its formation and its future are considered.

Acoustic vibration can enhance bacterial biofilm formation.

PubMed

Murphy, Mark F; Edwards, Thomas; Hobbs, Glyn; Shepherd, Joanna; Bezombes, Frederic

2016-12-01

This paper explores the use of low-frequency-low-amplitude acoustic vibration on biofilm formation. Biofilm development is thought to be governed by a diverse range of environmental signals and much effort has gone into researching the effects of environmental factors including; nutrient availability, pH and temperature on the growth of biofilms. Many biofilm-forming organisms have evolved to thrive in mechanically challenging environments, for example soil yet, the effects of the physical environment on biofilm formation has been largely ignored. Exposure of Pseudomonas aeruginosa to vibration at 100, 800 and 1600 Hz for 48 h, resulted in a significant increase in biofilm formation compared with the control, with the greatest growth seen at 800 Hz vibration. The results also show that this increase in biofilm formation is accompanied with an increase in P. aeruginosa cell number. Acoustic vibration was also found to regulate the spatial distribution of biofilm formation in a frequency-dependent manner. Exposure of Staphylococcus aureus to acoustic vibration also resulted in enhanced biofilm formation with the greatest level of biofilm being formed following 48 h exposure at 1600 Hz. These results show that acoustic vibration can be used to control biofilm formation and therefore presents a novel and potentially cost effective means to manipulate the development and yield of biofilms in a range of important industrial and medical processes. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Temperature controlled formation of lead/acid batteries

NASA Astrophysics Data System (ADS)

Bungardt, M.

At present, standard formation programs have to accommodate the worst case. This is important, especially in respect of variations in climatic conditions. The standard must be set so that during the hottest weather periods the maximum electrolyte temperature is not exceeded. As this value is defined not only by the desired properties and the recipe of the active mass, but also by type and size of the separators and by the dimensions of the plates, general rules cannot be formulated. It is considered to be advantageous to introduce limiting data for the maximum temperature into a general formation program. The latter is defined so that under normal to good ambient conditions the shortest formation time is achieved. If required, the temperature control will reduce the currents employed in the different steps, according to need, and will extend the formation time accordingly. With computer-controlled formation, these parameters can be readily adjusted to suit each type of battery and can also be reset according to modifications in the preceding processing steps. Such a procedure ensures that: (i) the formation time is minimum under the given ambient conditions; (ii) in the event of malpractice ( e.g. actual program not fitting to size) the batteries will not be destroyed; (iii) the energy consumption is minimized (note, high electrolyte temperature leads to excess gassing). These features are incorporated in the BA/FOS-500 battery formation system developed by Digatron. The operational characteristics of this system are listed in Table 1.

Format( )MEDIC( )Input

NASA Astrophysics Data System (ADS)

Foster, K.

1994-09-01

This document is a description of a computer program called Format( )MEDIC( )Input. The purpose of this program is to allow the user to quickly reformat wind velocity data in the Model Evaluation Database (MEDb) into a reasonable 'first cut' set of MEDIC input files (MEDIC.nml, StnLoc.Met, and Observ.Met). The user is cautioned that these resulting input files must be reviewed for correctness and completeness. This program will not format MEDb data into a Problem Station Library or Problem Metdata File. A description of how the program reformats the data is provided, along with a description of the required and optional user input and a description of the resulting output files. A description of the MEDb is not provided here but can be found in the RAS Division Model Evaluation Database Description document.

Cosmological structure formation

NASA Technical Reports Server (NTRS)

Schramm, David N.

1991-01-01

A summary of the current forefront problem of physical cosmology, the formation of structures (galaxies, clusters, great walls, etc.) in the universe is presented. Solutions require two key ingredients: (1) matter; and (2) seeds. Regarding the matter, it now seems clear that both baryonic and non-baryonic matter are required. Whether the non-baryonic matter is hot or cold depends on the choice of seeds. Regarding the seeds, both density fluctuations and topological defects are discussed. The combination of isotropy of the microwave background and the recent observations indicating more power on large scales have severly constrained, if not eliminated, Gaussian fluctuations with equal power on all scales, regardless of the eventual resolution of both the matter and seed questions. It is important to note that all current structure formation ideas require new physics beyond SU(3) x SU(2) x U(1).

The Dynamics of Planet Formation

NASA Astrophysics Data System (ADS)

Chambers, J. E.

2005-05-01

The transformation of a protoplanetary disk of gas and dust into a system of planets is a mysterious business that is frustratingly difficult to observe in detail. For this reason, studies of planet formation are largely based on theoretical models with only a few anchor points where precious observations are available. In this talk I will give an overview of some of these theoretical models, indicating areas of uncertainty and places where the models are on firmer ground. For convenience, theorists usually divide planet formation into a series of stages: formation of solid bodies from dust, aggregation of solid bodies into protoplanets, late-stage growth and the formation of giant planets, and planetary migration. Here I will concentrate mostly on the second and third of these stages (understanding of the first and last stages is rather limited, and the author's understanding is especially so). The intermediate stages involve interplay between several physical processes: physical collisions, gravitational scattering, dynamical friction, gas drag, and the capture and collapse of atmospheres. I will describe these processes in some detail, and show using analytical models how these effects can lead to a variety of planetary outcomes. This work was supported by NASA's Planetary Geology and Geophysics and TPF Foundation Science Mission programmes.

Elimination of formate production in Clostridium thermocellum.

PubMed

Rydzak, Thomas; Lynd, Lee R; Guss, Adam M

2015-09-01

The ability of Clostridium thermocellum to rapidly degrade cellulose and ferment resulting hydrolysis products into ethanol makes it a promising platform organism for cellulosic biofuel production via consolidated bioprocessing. Currently, however, ethanol yield is far below theoretical maximum due to branched product pathways that divert carbon and electrons towards formate, H2, lactate, acetate, and secreted amino acids. To redirect carbon and electron flux away from formate, genes encoding pyruvate:formate lyase (pflB) and PFL-activating enzyme (pflA) were deleted. Formate production in the resulting Δpfl strain was eliminated and acetate production decreased by 50 % on both complex and defined medium. The growth rate of the Δpfl strain decreased by 2.9-fold on defined medium and biphasic growth was observed on complex medium. Supplementation of defined medium with 2 mM formate restored Δpfl growth rate to 80 % of the parent strain. The role of pfl in metabolic engineering strategies and C1 metabolism is discussed.

[Pathogenesis of adhesions formation after intraabdominal operations].

PubMed

Voskanian, S É; Kyzlasov, P S

2011-01-01

The article describes the pathogenesis of adhesions formation after intraabdominal operations. Described predisposing factors leading of which is mechanical trauma, resulting from the use of surgical instruments, rough manipulations during surgery, damage to the mesothelium by dry gauze etc, which cause the adhesions. The pathogenesis of adhesions formation after intraabdominal surgery is presented in outline form, which described the changes occurring in the body starting with combination of predisposing factors and ending with the development of adhesions with blood vessels by 7-12 days after surgery. At the genetic level predisposition to adhesions formation and development of adhesive disease is treated as a manifestation of rapid acetylation phenotype, in which the intensity of fibrin formation exceeds normal rate of its catabolism. Thus, according to modem concepts, adhesive disease is a separate nosologic unit that dictates the necessity of its detailed study, development and introduction new universal methods of preventing the adhesions formation after intraabdominal operations.

Elimination of formate production in Clostridium thermocellum

DOE PAGES

Rydzak, Thomas; Lynd, Lee R.; Guss, Adam M.

2015-07-11

We study the ability of Clostridium thermocellum to rapidly degrade cellulose and ferment resulting hydrolysis products into ethanol makes it a promising platform organism for cellulosic biofuel production via consolidated bioprocessing. Currently, however, ethanol yield are far below theoretical maximum due to branched product pathways that divert carbon and electrons towards formate, H 2, lactate, acetate, and secreted amino acids. To redirect carbon and electron flux away from formate, pyruvate:formate lyase (pfl) and respective PFL-activating enzyme were deleted. Formate production in the resulting Δpfl strain was eliminated and acetate production decreased by 50% on both complex and defined medium. Growthmore » rate of Δpfl decreased by 2.9-fold on defined medium and diauxic growth was observed on complex medium. Supplementation of defined medium with 2 mM formate restored Δpfl growth rate to 80% of the parent strain. Finally, we discuss the role of pfl in metabolic engineering strategies and C 1 metabolism.« less

Globular cluster formation - The fossil record

NASA Technical Reports Server (NTRS)

Murray, Stephen D.; Lin, Douglas N. C.

1992-01-01

Properties of globular clusters which have remained unchanged since their formation are used to infer the internal pressures, cooling times, and dynamical times of the protocluster clouds immediately prior to the onset of star formation. For all globular clusters examined, it is found that the cooling times are much less than the dynamical times, implying that the protoclusters must have been maintained in thermal equilibrium by external heat sources, with fluxes consistent with those found in previous work, and giving the observed rho-T relation. Self-gravitating clouds cannot be stably heated, so that the Jeans mass forms an upper limit to the cluster masses. The observed dependence of protocluster pressure upon galactocentric position implies that the protocluster clouds were in hydrostatic equilibrium after their formation. The pressure dependence is well fitted by that expected for a quasi-statically evolving background hot gas, shock heated to its virial temperature. The observations and inferences are combined with previous theoretical work to construct a picture of globular cluster formation.

Online formative assessments: exploring their educational value

PubMed Central

NAGANDLA, KAVITHA; SULAIHA, SHARIFAH; NALLIAH, SIVALINGAM

2018-01-01

Introduction: Online formative assessments (OFA’s) have been increasingly recognised in medical education as resources that promote self-directed learning. Formative assessments are used to support the self-directed learning of students. Online formative assessments have been identified to be less time consuming with automated feedback. This pilot study aimed to determine whether participation and performance in online formative assessments (OFA’s) had measurable effects on learning and evaluate the students’ experience of using the OFA’s in the department of Obstetrics and Gynaecology. Methods: This is a cross-sectional study conducted among fourth year medical students (n=92) during their seven week postings in Obstetrics and Gynaecology. Five sets of online formative assessments in the format of one best answers (OBA), Objective structured practical examination (OSPE) and Short answer question (SAQ) with feedback were delivered over five weeks through the online portal. The mean scores of the end of posting summative exam (EOP) of those who participated in the assessments (OFA users) and of those who did not (non-OFA users) were compared, using Students t test. The frequency of tool usage was analysed and satisfaction surveys were utilized at the end of the course by survey questionnaire using the five point Likert scale. Results: The mean scores of the students in end of posting summative examination marks for students who had participated in the online formative assessment (OFA users) and for those who had not (non OFA users) showed no significant difference in all the three components OBA, SAQ and OSPE (p=0.902, 0.633, 0.248). Majority of the students perceived that OFAs fulfilled the stated aims and objectives and so they would persuade their peers to participate in the OFAs. Conclusions: Online formative assessments are perceived as tools that promote self-directed learning, improved knowledge and tailor learning for individual learning needs and

Designing Crowdcritique Systems for Formative Feedback

ERIC Educational Resources Information Center

Easterday, Matthew W.; Rees Lewis, Daniel; Gerber, Elizabeth M.

2017-01-01

Intelligent tutors based on expert systems often struggle to provide formative feedback on complex, ill-defined problems where answers are unknown. Hybrid crowdsourcing systems that combine the intelligence of multiple novices in face-to-face settings might provide an alternate approach for providing intelligent formative feedback. The purpose of…

Designing K-2 Formative Assessment Tasks

ERIC Educational Resources Information Center

Reed, Kristen E.; Goldenberg, E. Paul

2016-01-01

Formative assessment is a process used by teachers and students during instruction that provides feedback to adjust ongoing teaching and learning to improve students' achievements of intended instructional outcomes. Formative assessment means assessment embedded in instruction. That definition was adopted in 2006 by the Council of Chief State…

Influence of temperature on methane hydrate formation.

PubMed

Zhang, Peng; Wu, Qingbai; Mu, Cuicui

2017-08-11

During gas hydrate formation process, a phase transition of liquid water exists naturally, implying that temperature has an important influence on hydrate formation. In this study, methane hydrate was formed within the same media. The experimental system was kept at 1.45, 6.49, and 12.91 °C respectively, and then different pressurization modes were applied in steps. We proposed a new indicator, namely the slope of the gas flow rates against time (dν g /dt), to represent the intrinsic driving force for hydrate formation. The driving force was calculated as a fixed value at the different stages of formation, including initial nucleation/growth, secondary nucleation/growth, and decay. The amounts of gas consumed at each stage were also calculated. The results show that the driving force during each stage follows an inverse relation with temperature, whereas the amount of consumed gas is proportional to temperature. This opposite trend indicates that the influences of temperature on the specific formation processes and final amounts of gas contained in hydrate should be considered separately. Our results also suggest that the specific ambient temperature under which hydrate is formed should be taken into consideration, when explaining the formation of different configurations and saturations of gas hydrates in natural reservoirs.

Millimeter Wave Spectrum and Astronomical Search for Vinyl Formate

NASA Astrophysics Data System (ADS)

Alonso, E. R.; Kolesniková, L.; Tercero, B.; Cabezas, C.; Alonso, J. L.; Cernicharo, J.; Guillemin, J.-C.

2016-11-01

Previous detections of methyl and ethyl formate make other small substituted formates potential candidates for observation in the interstellar medium. Among them, vinyl formate is one of the simplest unsaturated carboxylic ester. The aim of this work is to provide direct experimental frequencies of the ground vibrational state of vinyl formate in a large spectral range for astrophysical use. The room-temperature rotational spectrum of vinyl formate has been measured from 80 to 360 GHz and analyzed in terms of Watson’s semirigid rotor Hamiltonian. Two thousand six hundred transitions within J = 3-88 and K a = 0-28 were assigned to the most stable conformer of vinyl formate and a new set of spectroscopic constants was accurately determined. Spectral features of vinyl formate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of vinyl formate are provided.

MILLIMETER WAVE SPECTRUM AND ASTRONOMICAL SEARCH FOR VINYL FORMATE

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

Alonso, E. R.; Kolesniková, L.; Cabezas, C.

2016-11-20

Previous detections of methyl and ethyl formate make other small substituted formates potential candidates for observation in the interstellar medium. Among them, vinyl formate is one of the simplest unsaturated carboxylic ester. The aim of this work is to provide direct experimental frequencies of the ground vibrational state of vinyl formate in a large spectral range for astrophysical use. The room-temperature rotational spectrum of vinyl formate has been measured from 80 to 360 GHz and analyzed in terms of Watson’s semirigid rotor Hamiltonian. Two thousand six hundred transitions within J = 3–88 and K {sub a} = 0–28 were assignedmore » to the most stable conformer of vinyl formate and a new set of spectroscopic constants was accurately determined. Spectral features of vinyl formate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of vinyl formate are provided.« less

Heart disease management by women: does intervention format matter?

PubMed

Clark, Noreen M; Janz, Nancy K; Dodge, Julia A; Lin, Xihong; Trabert, Britton L; Kaciroti, Niko; Mosca, Lori; Wheeler, John R; Keteyian, Steven

2009-04-01

A randomized controlled trial of two formats of a program (Women Take PRIDE) to enhance management of heart disease by patients was conducted. Older women (N = 575) were randomly assigned to a group or self-directed format or to a control group. Data regarding symptoms, functional health status, and weight were collected at baseline and at 4, 12, and 18 months. The formats produced different outcomes. At 18 months, the self-directed format was better than the control in reducing the number (p < or = .02), frequency (p < or = .03), and bothersomeness (p < or = .02) of cardiac symptoms. The self-directed format was also better than the group format in reducing symptom frequency of all types (p < or = .04). The group format improved ambulation at 12 months (p < or = .04) and weight loss at 18 months (p < or = .03), and group participants were more likely to complete the program ( p < or = .05). The availability of different learning formats could enhance management of cardiovascular disease by patients.

Fostering Spiritual Formation of Millennials in Christian Schools

ERIC Educational Resources Information Center

Horan, Anne Puidk

2017-01-01

Christian education seeks to foster millennials' spiritual formation to equip them for future challenges and to benefit society. Using nonexperimental mixed methods, 504 secondary educators revealed what spiritual formation programs their schools implement and their perceptions about millennial spiritual formation. Descriptive analysis showed that…

7 CFR 51.612 - Fairly good heart formation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Fairly good heart formation. 51.612 Section 51.612....612 Fairly good heart formation. Fairly good heart formation means that the stalk has a moderate number of fairly stocky inner heart branches for its size. ...

7 CFR 51.612 - Fairly good heart formation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Fairly good heart formation. 51.612 Section 51.612....612 Fairly good heart formation. Fairly good heart formation means that the stalk has a moderate number of fairly stocky inner heart branches for its size. ...

The variant call format and VCFtools.

PubMed

Danecek, Petr; Auton, Adam; Abecasis, Goncalo; Albers, Cornelis A; Banks, Eric; DePristo, Mark A; Handsaker, Robert E; Lunter, Gerton; Marth, Gabor T; Sherry, Stephen T; McVean, Gilean; Durbin, Richard

2011-08-01

The variant call format (VCF) is a generic format for storing DNA polymorphism data such as SNPs, insertions, deletions and structural variants, together with rich annotations. VCF is usually stored in a compressed manner and can be indexed for fast data retrieval of variants from a range of positions on the reference genome. The format was developed for the 1000 Genomes Project, and has also been adopted by other projects such as UK10K, dbSNP and the NHLBI Exome Project. VCFtools is a software suite that implements various utilities for processing VCF files, including validation, merging, comparing and also provides a general Perl API. http://vcftools.sourceforge.net

High mass star formation in the galaxy

NASA Technical Reports Server (NTRS)

Scoville, N. Z.; Good, J. C.

1987-01-01

The Galactic distributions of HI, H2, and HII regions are reviewed in order to elucidate the high mass star formation occurring in galactic spiral arms and in active galactic nuclei. Comparison of the large scale distributions of H2 gas and radio HII regions reveals that the rate of formation of OB stars depends on (n sub H2) sup 1.9 where (n sub H2) is the local mean density of H2 averaged over 300 pc scale lengths. In addition the efficiency of high mass star formation is a decreasing function of cloud mass in the range 200,000 to 3,000,000 solar mass. These results suggest that high mass star formation in the galactic disk is initiated by cloud-cloud collisions which are more frequent in the spiral arms due to orbit crowding. Cloud-cloud collisions may also be responsible for high rates of OB star formation in interacting galaxies and galactic nuclei. Based on analysis of the Infrared Astronomy Satellite (IRAS) and CO data for selected GMCs in the Galaxy, the ratio L sub IR/M sub H2 can be as high as 30 solar luminosity/solar mass for GMCs associated with HII regions. The L sub IR/M sub H2 ratios and dust temperature obtained in many of the high luminosity IRAS galaxies are similar to those encountered in galactic GMCs with OB star formation. High mass star formation is therefore a viable explanation for the high infrared luminosity of these galaxies.

LARSPEC spectroradiometer-multiband radiometer data formats

NASA Technical Reports Server (NTRS)

Biehl, L. L.

1982-01-01

The data base software system, LARSPEC, is discussed and the data base format for agronomic, meteorological, spectroradiometer, and multiband radiometer data is described. In addition, the contents and formats of each record of data and the wavelength tables are listed and the codes used for some of the parameters are described.

Island Formation: Constructing a Coral Island

ERIC Educational Resources Information Center

Austin, Heather; Edd, Amelia

2009-01-01

The process of coral island formation is often difficult for middle school students to comprehend. Coral island formation is a dynamic process, and students should have the opportunity to experience this process in a synergistic context. The authors provide instructional guidelines for constructing a coral island. Students play an interactive role…

Story Problem Formats: Verbal Versus Telegraphic.

ERIC Educational Resources Information Center

Moyer, John C.; And Others

1984-01-01

Students in grades three to seven were given tests on which problems were presented in either verbal or telegraphic format. Only in grade six was a significant difference found, favoring the verbal format. Problems with conventional syntax appeared to be easier to interpret than those with bare bones syntax. (MNS)

21 CFR 573.170 - Ammonium formate.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.170 Ammonium formate. The food additive, partially ammonium formate, may be safely used in...) To assure safe use of the additive, in addition to the other information required by the Federal Food...

21 CFR 573.170 - Ammonium formate.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.170 Ammonium formate. The food additive, partially ammonium formate, may be safely used in...) To assure safe use of the additive, in addition to the other information required by the Federal Food...

21 CFR 573.170 - Ammonium formate.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.170 Ammonium formate. The food additive, ammonium formate, may be safely used in the... safe use of the additive, in addition to the other information required by the Federal Food, Drug, and...

21 CFR 573.170 - Ammonium formate.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.170 Ammonium formate. The food additive, partially ammonium formate, may be safely used in...) To assure safe use of the additive, in addition to the other information required by the Federal Food...

TOLNet Data Format for Lidar Ozone Profile & Surface Observations

NASA Astrophysics Data System (ADS)

Chen, G.; Aknan, A. A.; Newchurch, M.; Leblanc, T.

2015-12-01

The Tropospheric Ozone Lidar Network (TOLNet) is an interagency initiative started by NASA, NOAA, and EPA in 2011. TOLNet currently has six Lidars and one ozonesonde station. TOLNet provides high-resolution spatio-temporal measurements of tropospheric (surface to tropopause) ozone and aerosol vertical profiles to address fundamental air-quality science questions. The TOLNet data format was developed by TOLNet members as a community standard for reporting ozone profile observations. The development of this new format was primarily based on the existing NDAAC (Network for the Detection of Atmospheric Composition Change) format and ICARTT (International Consortium for Atmospheric Research on Transport and Transformation) format. The main goal is to present the Lidar observations in self-describing and easy-to-use data files. The TOLNet format is an ASCII format containing a general file header, individual profile headers, and the profile data. The last two components repeat for all profiles recorded in the file. The TOLNet format is both human and machine readable as it adopts standard metadata entries and fixed variable names. In addition, software has been developed to check for format compliance. To be presented is a detailed description of the TOLNet format protocol and scanning software.

Efficient stereoscopic contents file format on the basis of ISO base media file format

NASA Astrophysics Data System (ADS)

Kim, Kyuheon; Lee, Jangwon; Suh, Doug Young; Park, Gwang Hoon

2009-02-01

A lot of 3D contents haven been widely used for multimedia services, however, real 3D video contents have been adopted for a limited applications such as a specially designed 3D cinema. This is because of the difficulty of capturing real 3D video contents and the limitation of display devices available in a market. However, diverse types of display devices for stereoscopic video contents for real 3D video contents have been recently released in a market. Especially, a mobile phone with a stereoscopic camera has been released in a market, which provides a user as a consumer to have more realistic experiences without glasses, and also, as a content creator to take stereoscopic images or record the stereoscopic video contents. However, a user can only store and display these acquired stereoscopic contents with his/her own devices due to the non-existence of a common file format for these contents. This limitation causes a user not share his/her contents with any other users, which makes it difficult the relevant market to stereoscopic contents is getting expanded. Therefore, this paper proposes the common file format on the basis of ISO base media file format for stereoscopic contents, which enables users to store and exchange pure stereoscopic contents. This technology is also currently under development for an international standard of MPEG as being called as a stereoscopic video application format.

Cosmic strings and galaxy formation

NASA Technical Reports Server (NTRS)

Bertschinger, Edmund

1989-01-01

The cosmogonical model proposed by Zel'dovich and Vilenkin (1981), in which superconducting cosmic strings act as seeds for the origin of structure in the universe, is discussed, summarizing the results of recent theoretical investigations. Consideration is given to the formation of cosmic strings, the microscopic structure of strings, gravitational effects, cosmic string evolution, and the formation of galaxies and large-scale structure. Simulation results are presented in graphs, and several outstanding issues are listed and briefly characterized.

Structure formation in nonlocal MOND

NASA Astrophysics Data System (ADS)

Tan, L.; Woodard, R. P.

2018-05-01

We consider structure formation in a nonlocal, metric-based realization of Milgrom's MOdified Newtonian Dynamics (MOND). We derive the general equations for linearized scalar perturbations about the ΛCDM expansion history. These equations are considerably simplified for sub-horizon modes, and it becomes obvious (in this model) that the MOND enhancement is not sufficient to allow ordinary matter to drive structure formation. We discuss ways in which the model might be changed to correct the problem.

16 CFR 801.50 - Formation of unincorporated entities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Formation of unincorporated entities. 801.50... of unincorporated entities. (a) In the formation of an unincorporated entity (other than in... entity and the unincorporated entity itself may, in the formation transaction, be both acquiring and...

16 CFR 801.50 - Formation of unincorporated entities.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Formation of unincorporated entities. 801.50... of unincorporated entities. (a) In the formation of an unincorporated entity (other than in... entity and the unincorporated entity itself may, in the formation transaction, be both acquiring and...

Star formation in evolving molecular clouds

NASA Astrophysics Data System (ADS)

Völschow, M.; Banerjee, R.; Körtgen, B.

2017-09-01

Molecular clouds are the principle stellar nurseries of our universe; they thus remain a focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many questions regarding their evolution and star formation activity remain open. While numerical simulations feature a large number and complexity of involved physical processes, this plethora of effects may hide the fundamentals that determine the evolution of molecular clouds and enable the formation of stars. Purely analytical models, on the other hand, tend to suffer from rough approximations or a lack of completeness, limiting their predictive power. In this paper, we present a model that incorporates central concepts of astrophysics as well as reliable results from recent simulations of molecular clouds and their evolutionary paths. Based on that, we construct a self-consistent semi-analytical framework that describes the formation, evolution, and star formation activity of molecular clouds, including a number of feedback effects to account for the complex processes inside those objects. The final equation system is solved numerically but at much lower computational expense than, for example, hydrodynamical descriptions of comparable systems. The model presented in this paper agrees well with a broad range of observational results, showing that molecular cloud evolution can be understood as an interplay between accretion, global collapse, star formation, and stellar feedback.

Overactive bladder and pontine reticular formation.

PubMed

Zorba, Orhan Ünal; Kırbaş, Serkan; Uzun, Hakkı; Cetinkaya, Mehmet; Önem, Kadir; Rifaioğlu, Mehmet Murat

2013-01-01

The etiology of overactive bladder (OAB) remains unclear. Observed neurogenic factors in the literature are limited to suprapontine or spinal pathologies. The blink reflex is a useful tool in the evaluation of brainstem functions. Blink reflex latency times were evaluated in order to reveal pathology in the brainstem. A total of 60 women, 30 patients with idiopathic OAB and 30 healthy controls, were enrolled in the study. Blink reflex latency times were analyzed by electrical stimulation of the supraorbital nerve. Two responses in the orbicularis oculi muscle, early ipsilateral response (R1) and late bilateral response (R2) latency times, were recorded. Mean ages of the patients and controls were 51.9 ± 5.3 and 49.2 ± 6.2 years, respectively. R2 latency times were significantly higher in patients than in controls. However, R1 latency times were similar between the two groups. The results of the study suggest a significant relation between late blink latency times and OAB. An oligosynaptic path via the trigeminal nuclei is responsible for R1; however, R2 response is relayed through the reticular formation. Stimulation of pontine reticular formation inhibits micturition contraction. In some patients, idiopathic OAB may result from reticular formation-originated pathology. Additional studies on other reticular formation-mediated reflexes are needed to reveal possible dysfunction of reticular formation. Copyright © 2013 S. Karger AG, Basel.

Production from multiple zones of a tar sands formation

DOEpatents

Karanikas, John Michael; Vinegar, Harold J

2013-02-26

A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat is allowed to transfer from the heaters to at least a portion of the formation. Fluids are produced from the formation through at least one production well that is located in at least two zones in the formation. The first zone has an initial permeability of at least 1 darcy. The second zone has an initial of at most 0.1 darcy. The two zones are separated by a substantially impermeable barrier.

Format-Preserving Encryption

NASA Astrophysics Data System (ADS)

Bellare, Mihir; Ristenpart, Thomas; Rogaway, Phillip; Stegers, Till

Format-preserving encryption (FPE) encrypts a plaintext of some specified format into a ciphertext of identical format—for example, encrypting a valid credit-card number into a valid credit-card number. The problem has been known for some time, but it has lacked a fully general and rigorous treatment. We provide one, starting off by formally defining FPE and security goals for it. We investigate the natural approach for achieving FPE on complex domains, the “rank-then-encipher” approach, and explore what it can and cannot do. We describe two flavors of unbalanced Feistel networks that can be used for achieving FPE, and we prove new security results for each. We revisit the cycle-walking approach for enciphering on a non-sparse subset of an encipherable domain, showing that the timing information that may be divulged by cycle walking is not a damaging thing to leak.

Formative Feedback in a Malaysian Primary School ESL Context

ERIC Educational Resources Information Center

Sardareh, Sedigheh Abbasnasab

2016-01-01

The idea of providing students with formative feedback is a crucial part of formative assessment. Teachers need to provide students with feedback that improves their learning. In other words, formative feedback should provide learners with information that help them bridge their learning gap. As formative assessment itself is a newly introduced…

Elementary Teacher Use of Formative Assessment

ERIC Educational Resources Information Center

Cotton, Donna McLamb

2013-01-01

This dissertation was designed to examine elementary teacher use of formative assessment and the impact formative assessment may have on student achievement as measured by benchmark assessments. The study was conducted in a school district in northwestern North Carolina. The teachers in this study have had NCFALCON training in the use of formative…

Power systems utilizing the heat of produced formation fluid

DOEpatents

Lambirth, Gene Richard [Houston, TX

2011-01-11

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method includes treating a hydrocarbon containing formation. The method may include providing heat to the formation; producing heated fluid from the formation; and generating electricity from at least a portion of the heated fluid using a Kalina cycle.

A Faculty Toolkit for Formative Assessment in Pharmacy Education.

PubMed

DiVall, Margarita V; Alston, Greg L; Bird, Eleanora; Buring, Shauna M; Kelley, Katherine A; Murphy, Nanci L; Schlesselman, Lauren S; Stowe, Cindy D; Szilagyi, Julianna E

2014-11-15

This paper aims to increase understanding and appreciation of formative assessment and its role in improving student outcomes and the instructional process, while educating faculty on formative techniques readily adaptable to various educational settings. Included are a definition of formative assessment and the distinction between formative and summative assessment. Various formative assessment strategies to evaluate student learning in classroom, laboratory, experiential, and interprofessional education settings are discussed. The role of reflective writing and portfolios, as well as the role of technology in formative assessment, are described. The paper also offers advice for formative assessment of faculty teaching. In conclusion, the authors emphasize the importance of creating a culture of assessment that embraces the concept of 360-degree assessment in both the development of a student's ability to demonstrate achievement of educational outcomes and a faculty member's ability to become an effective educator.

Dust formation at low metallicity

NASA Astrophysics Data System (ADS)

Ferrarotti, A. S.; Gail, H.-P.

Stars between 3Modot and 25Modot reach their final stages of stellar evolution either as AGB (asymptotic giant branch) stars and finally become white dwarfs, or end in a supernova explosion. The last evolutionary stages, shortly before the final state, are regularly accompanied by stellar winds which lead to substantial mass loss and develop optically very thick dust shells. Mass loss for smaller and medium sized stars higher up on the AGB depends predominantly on the metallicity of the star. For Pop I metallicity, the mass loss is caused by dust condensation. This process is not possible for stars of small Z. Thus, their final evolution strongly depends on the possibility of dust formation. Our research focuses on the dependence of dust formation of the first stellar generation on Z and on the initial mass of the star. Furthermore, we investigate when dust formation becomes possible in stellar winds and the effects this process has on the evolution of the star at the final evolutionary stages. With synthetic AGB evolution models some important issues in stellar evolution can tried to be answered: (1) mass loss on the AGB, (2) the shift of the limit (γ>1) for the onset of dust driven winds with Z and (3) the critical Z when dust formation becomes possible.

Transfer of Solutions to Conditional Probability Problems: Effects of Example Problem Format, Solution Format, and Problem Context

ERIC Educational Resources Information Center

Chow, Alan F.; Van Haneghan, James P.

2016-01-01

This study reports the results of a study examining how easily students are able to transfer frequency solutions to conditional probability problems to novel situations. University students studied either a problem solved using the traditional Bayes formula format or using a natural frequency (tree diagram) format. In addition, the example problem…

Formation of planetesimals

NASA Technical Reports Server (NTRS)

Weidenschilling, Stuart J.

1991-01-01

Formation of planetesimals is discussed. The following subject areas are covered: (1) nebular structure; (2) aerodynamics of the solid bodies in the nebula; (3) problems with gravitational instability; (4) particle growth by coagulation; properties of fractal aggregates; and (5) coagulation and settling of fractal aggregates.

7 CFR 51.612 - Fairly good heart formation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly good heart formation. 51.612 Section 51.612... STANDARDS) United States Consumer Standards for Celery Stalks Definitions § 51.612 Fairly good heart formation. Fairly good heart formation means that the stalk has a moderate number of fairly stocky inner...

7 CFR 51.612 - Fairly good heart formation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Fairly good heart formation. 51.612 Section 51.612... STANDARDS) United States Consumer Standards for Celery Stalks Definitions § 51.612 Fairly good heart formation. Fairly good heart formation means that the stalk has a moderate number of fairly stocky inner...

7 CFR 51.612 - Fairly good heart formation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Fairly good heart formation. 51.612 Section 51.612... STANDARDS) United States Consumer Standards for Celery Stalks Definitions § 51.612 Fairly good heart formation. Fairly good heart formation means that the stalk has a moderate number of fairly stocky inner...

Specific plant induced biofilm formation in Methylobacterium species.

PubMed

Rossetto, Priscilla B; Dourado, Manuella N; Quecine, Maria C; Andreote, Fernando D; Araújo, Welington L; Azevedo, João L; Pizzirani-Kleiner, Aline A

2011-07-01

Two endophytic strains of Methylobacterium spp. were used to evaluate biofilm formation on sugarcane roots and on inert wooden sticks. Results show that biofilm formation is variable and that plant surface and possibly root exudates have a role in Methylobacterium spp. host recognition, biofilm formation and successful colonization as endophytes.

40 CFR 158.32 - Format of data submissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Format of data submissions. 158.32... DATA REQUIREMENTS FOR PESTICIDES General Provisions § 158.32 Format of data submissions. (a) General. (1) All data submitted under this part must be formatted in accordance with this section. (2) The...

Thermodynamics of impurity-enhanced vacancy formation in metals

NASA Astrophysics Data System (ADS)

Bukonte, Laura; Ahlgren, Tommy; Heinola, Kalle

2017-01-01

Hydrogen induced vacancy formation in metals and metal alloys has been of great interest during the past couple of decades. The main reason for this phenomenon, often referred to as the superabundant vacancy formation, is the lowering of vacancy formation energy due to the trapping of hydrogen. By means of thermodynamics, we study the equilibrium vacancy formation in fcc metals (Pd, Ni, Co, and Fe) in correlation with the H amounts. The results of this study are compared and found to be in good agreement with experiments. For the accurate description of the total energy of the metal-hydrogen system, we take into account the binding energies of each trapped impurity, the vibrational entropy of defects, and the thermodynamics of divacancy formation. We demonstrate the effect of vacancy formation energy, the hydrogen binding, and the divacancy binding energy on the total equilibrium vacancy concentration. We show that the divacancy fraction gives the major contribution to the total vacancy fraction at high H fractions and cannot be neglected when studying superabundant vacancies. Our results lead to a novel conclusion that at high hydrogen fractions, superabundant vacancy formation takes place regardless of the binding energy between vacancies and hydrogen. We also propose the reason of superabundant vacancy formation mainly in the fcc phase. The equations obtained within this work can be used for any metal-impurity system, if the impurity occupies an interstitial site in the lattice.

Heart disease management by women: does intervention format matter?

PubMed

Clark, Noreen M; Janz, Nancy K; Dodge, Julia A; Lin, Xihong; Trabert, Britton L; Kaciroti, Niko; Mosca, Lori; Wheeler, John R; Keteyian, Steven

2014-10-01

A randomized controlled trial of two formats of a program (Women Take PRIDE) to enhance management of heart disease by patients was conducted. Older women (N = 575) were randomly assigned to a group or self-directed format or to a control group. Data regarding symptoms, functional health status, and weight were collected at baseline and at 4, 12, and 18 months. The formats produced different outcomes. At 18 months, the self-directed format was better than the control in reducing the number (p ≤ .02), frequency (p ≤ .03), and bothersomeness (p ≤ .02) of cardiac symptoms. The self-directed format was also better than the group format in reducing symptom frequency of all types (p ≤ .04). The group format improved ambulation at 12 months (p ≤ .04) and weight loss at 18 months (p ≤ .03), and group participants were more likely to complete the program (p ≤ .05). The availability of different learning formats could enhance management of cardiovascular disease by patients. © 2014 Society for Public Health Education.

Complex organic molecules and star formation

NASA Astrophysics Data System (ADS)

Bacmann, A.; Faure, A.

2014-12-01

Star forming regions are characterised by the presence of a wealth of chemical species. For the past two to three decades, ever more complex organic species have been detected in the hot cores of protostars. The evolution of these molecules in the course of the star forming process is still uncertain, but it is likely that they are partially incorporated into protoplanetary disks and then into planetesimals and the small bodies of planetary systems. The complex organic molecules seen in star forming regions are particularly interesting since they probably make up building blocks for prebiotic chemistry. Recently we showed that these species were also present in the cold gas in prestellar cores, which represent the very first stages of star formation. These detections question the models which were until now accepted to account for the presence of complex organic molecules in star forming regions. In this article, we shortly review our current understanding of complex organic molecule formation in the early stages of star formation, in hot and cold cores alike and present new results on the formation of their likely precursor radicals.

Mineralogical signatures of stone formation mechanisms.

PubMed

Gower, Laurie B; Amos, Fairland F; Khan, Saeed R

2010-08-01

The mechanisms involved in biomineralization are modulated through interactions with organic matrix. In the case of stone formation, the role of the organic macromolecules in the complex urinary environment is not clear, but the presence of mineralogical 'signatures' suggests that some aspects of stone formation may result from a non-classical crystallization process that is induced by acidic proteins. An amorphous precursor has been detected in many biologically controlled mineralization reactions, which is thought to be regulated by non-specific interactions between soluble acidic proteins and mineral ions. Using in vitro model systems, we find that a liquid-phase amorphous mineral precursor induced by acidic polypeptides can lead to crystal textures that resemble those found in Randall's plaque and kidney stones. This polymer-induced liquid-precursor process leads to agglomerates of coalesced mineral spherules, dense-packed spherulites with concentric laminations, mineral coatings and 'cements', and collagen-associated mineralization. Through the use of in vitro model systems, the mechanisms involved in the formation of these crystallographic features may be resolved, enhancing our understanding of the potential role(s) that proteins play in stone formation.

18 CFR 270.304 - Tight formation gas.

Code of Federal Regulations, 2011 CFR

2011-04-01

... determination that natural gas is tight formation gas must file with the jurisdictional agency an application... formation; (d) A complete copy of the well log, including the log heading identifying the designated tight...

Automated Oligopeptide Formation Under Simple Programmable Conditions

NASA Astrophysics Data System (ADS)

Suárez-Marina, I.; Rodriguez-Garcia, M.; Surman, A. J.; Cooper, G. J. T.; Cronin, L.

2017-07-01

Traditionally, prebiotic chemistry has investigated the formation of life's precursors under very specific conditions thought to be "plausible". Herein, we explore peptide formation studying several parameters at once by using an automated platform.

Formation Flying of Tethered and Nontethered Spacecraft

NASA Technical Reports Server (NTRS)

Quadrelli, Marco B.

2005-01-01

A paper discusses the effect of the dynamic interaction taking place within a formation composed of a rigid and a deformable vehicle, and presents the concept of two or more tethered spacecraft flying in formation with one or more separated free-flying spacecraft. Although progress toward formation flight of nontethered spacecraft has already been achieved, the document cites potential advantages of tethering, including less consumption of fuel to maintain formation, very high dynamic stability of a rotating tethered formation, and intrinsically passive gravity-gradient stabilization. The document presents a theoretical analysis of the dynamics of a system comprising one free-flying spacecraft and two tethered spacecraft in orbit, as a prototype of more complex systems. The spacecraft are modeled as rigid bodies and the tether as a mass-less spring with structural viscous damping. Included in the analysis is a study of the feasibility of a centralized control system for maintaining a required formation in low Earth orbit. A numerical simulation of a retargeting maneuver is reported to show that even if the additional internal dynamics of the system caused by flexibility is considered, high pointing precision can be achieved if a fictitious rigid frame is used to track the tethered system, and it should be possible to position the spacecraft with centimeter accuracy and to orient the formation within arc seconds of the desired direction also in the presence of low Earth orbit environmental perturbations. The results of the study demonstrate that the concept is feasible in Earth orbit and point the way to further study of these hybrid tethered and free-flying systems for related applications in orbit around other Solar System bodies.

A Simple Non-equilibrium Model of Star Formation and Scatter in the Kennicutt-Schmidt Relation and Star Formation Efficiencies in Galaxies

NASA Astrophysics Data System (ADS)

Orr, Matthew; Hopkins, Philip F.

2018-06-01

I will present a simple model of non-equilibrium star formation and its relation to the scatter in the Kennicutt-Schmidt relation and large-scale star formation efficiencies in galaxies. I will highlight the importance of a hierarchy of timescales, between the galaxy dynamical time, local free-fall time, the delay time of stellar feedback, and temporal overlap in observables, in setting the scatter of the observed star formation rates for a given gas mass. Further, I will talk about how these timescales (and their associated duty-cycles of star formation) influence interpretations of the large-scale star formation efficiency in reasonably star-forming galaxies. Lastly, the connection with galactic centers and out-of-equilibrium feedback conditions will be mentioned.

Ethylene formation by polymorphonuclear leukocytes. Role of myeloperoxidase

PubMed Central

1978-01-01

Ethylene formation from the thioethers, beta-methylthiopropionaldehyde (methional) and 2-keto-4-thiomethylbutyric acid by phagocytosing polymorphonuclear leukocytes (PMNs) was found to be largely dependent on myeloperoxidase (MPO). Conversion was less than 10% of normal when MPO-deficient PMNs were employed; formation by normal PMNs was inhibited by the peroxidase inhibitors, azide, and cyanide, and a model system consisting of MPO, H2O2, chloride (or bromide) and EDTA was found which shared many of the properties of the predominant PMN system. MPO-independent mechanisms of ethylene formation were also identified. Ethylene formation from methional by phagocytosing eosinophils and by H2O2 in the presence or absence of catalase was stimulated by azide. The presence of MPO-independent, azide-stimulable systems in the PMN preparations was suggested by the azide stimulation of ethylene formation from methional when MPO-deficient leukocytes were employed. Ethylene formation by dye-sensitized photooxidation was also demonstrated and evidence obtained for the involvement of singlet oxygen (1O2). These findings are discussed in relation to the participation of H2O2, hydroxyl radicals, the superoxide anion and 1O2 in the formation of ethylene by PMNs and by the MPO model system. PMID:212502

Reversible cluster formation in concentrated monoclonal antibody solutions

NASA Astrophysics Data System (ADS)

Godfrin, P. Douglas; Porcar, Lionel; Falus, Peter; Zarraga, Isidro; Wagner, Norm; Liu, Yun

2015-03-01

Protein cluster formation in solution is of fundamental interest for both academic research and industrial applications. Recently, industrial scientists are also exploring the effect of reversible cluster formation on biopharmaceutical processing and delivery. However, despite of its importance, the understanding of protein clusters at concentrated solutions remains scientifically very challenging. Using the neutron spin echo technique to study the short time dynamics of proteins in solutions, we have recently systematically studied cluster formation in a few monoclonal antibody (mAb) solutions and their relation with solution viscosity. We show that the existence of anisotropic attraction can cause the formation of finite sized clusters, which increases the solution viscosity. Interestingly, once clusters form at relatively low concentrations, the average size of clusters in solutions remains almost constant over a wide range of concentrations similar to that of micelle formation. For a different mAb we have also investigated, the attraction is mostly induced by hydrophobic patches. As a result, these mAbs form large clusters with loosely linked proteins. In both cases, the formation of clusters all increases the solution viscosity substantially. However, due to different physics origins of cluster formation, solutions viscosities for these two different types of mAbs need to be controlled by different ways.

Galaxy Zoo: star formation versus spiral arm number

NASA Astrophysics Data System (ADS)

Hart, Ross E.; Bamford, Steven P.; Casteels, Kevin R. V.; Kruk, Sandor J.; Lintott, Chris J.; Masters, Karen L.

2017-06-01

Spiral arms are common features in low-redshift disc galaxies, and are prominent sites of star formation and dust obscuration. However, spiral structure can take many forms: from galaxies displaying two strong 'grand design' arms to those with many 'flocculent' arms. We investigate how these different arm types are related to a galaxy's star formation and gas properties by making use of visual spiral arm number measurements from Galaxy Zoo 2. We combine ultraviolet and mid-infrared (MIR) photometry from GALEX and WISE to measure the rates and relative fractions of obscured and unobscured star formation in a sample of low-redshift SDSS spirals. Total star formation rate has little dependence on spiral arm multiplicity, but two-armed spirals convert their gas to stars more efficiently. We find significant differences in the fraction of obscured star formation: an additional ˜10 per cent of star formation in two-armed galaxies is identified via MIR dust emission, compared to that in many-armed galaxies. The latter are also significantly offset below the IRX-β relation for low-redshift star-forming galaxies. We present several explanations for these differences versus arm number: variations in the spatial distribution, sizes or clearing time-scales of star-forming regions (I.e. molecular clouds), or contrasting recent star formation histories.

Specific plant induced biofilm formation in Methylobacterium species

PubMed Central

Rossetto, Priscilla B.; Dourado, Manuella N.; Quecine, Maria C.; Andreote, Fernando D.; Araújo, Welington L.; Azevedo, João L.; Pizzirani-Kleiner, Aline A.

2011-01-01

Two endophytic strains of Methylobacterium spp. were used to evaluate biofilm formation on sugarcane roots and on inert wooden sticks. Results show that biofilm formation is variable and that plant surface and possibly root exudates have a role in Methylobacterium spp. host recognition, biofilm formation and successful colonization as endophytes. PMID:24031703

The formation of stellar systems from interstellar molecular clouds.

PubMed

Gehrz, R D; Black, D C; Solomon, P M

1984-05-25

Star formation, a crucial link in the chain of events that led from the early expansion of the universe to the formation of the solar system, continues to play a major role in the evolution of many galaxies. Observational and theoretical studies of regions of ongoing star formation provide insight into the physical conditions and events that must have attended the formation of the solar system. Such investigations also elucidate the role played by star formation in the evolutionary cycle which appears to dominate the chemical processing of interstellar material by successive generations of stars in spiral galaxies like our own. New astronomical facilities planned for development during the 1980's could lead to significant advances in our understanding of the star formation process. Efforts to identify and examine both the elusive protostellar collapse phase of star formation and planetary systems around nearby stars will be especially significant.

A Faculty Toolkit for Formative Assessment in Pharmacy Education

PubMed Central

Alston, Greg L.; Bird, Eleanora; Buring, Shauna M.; Kelley, Katherine A.; Murphy, Nanci L.; Schlesselman, Lauren S.; Stowe, Cindy D.; Szilagyi, Julianna E.

2014-01-01

This paper aims to increase understanding and appreciation of formative assessment and its role in improving student outcomes and the instructional process, while educating faculty on formative techniques readily adaptable to various educational settings. Included are a definition of formative assessment and the distinction between formative and summative assessment. Various formative assessment strategies to evaluate student learning in classroom, laboratory, experiential, and interprofessional education settings are discussed. The role of reflective writing and portfolios, as well as the role of technology in formative assessment, are described. The paper also offers advice for formative assessment of faculty teaching. In conclusion, the authors emphasize the importance of creating a culture of assessment that embraces the concept of 360-degree assessment in both the development of a student’s ability to demonstrate achievement of educational outcomes and a faculty member’s ability to become an effective educator. PMID:26056399

Theories of Giant Planet Formation

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.; Young, Richard E. (Technical Monitor)

1998-01-01

An overview of current theories of planetary formation, with emphasis on giant planets, is presented. The most detailed models are based upon observations of our own Solar System and of young stars and their environments. While these models predict that rocky planets should form around most single stars, the frequency of formation of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Most models for extrasolar giant planets suggest that they formed as did Jupiter and Saturn (in nearly circular orbits, far enough from the star that ice could), and subsequently migrated to their current positions, although some models suggest in situ formation.

Theory of Planetary System Formation

NASA Technical Reports Server (NTRS)

Cassen, Patrick

1996-01-01

Observations and theoretical considerations support the idea that the Solar System formed by the collapse of tenuous interstellar matter to a disk of gas and dust (the primitive solar nebula), from which the Sun and other components separated under the action of dissipative forces and by the coagulation of solid material. Thus, planets are understood to be contemporaneous byproducts of star formation. Because the circumstellar disks of new stars are easier to observe than mature planetary systems, the possibility arises that the nature and variety of planets might be studied from observations of the conditions of their birth. A useful theory of planetary system formation would therefore relate the properties of circumstellar disks both to the initial conditions of star formation and to the consequent properties of planets to those of the disk. Although the broad outlines of such a theory are in place, many aspects are either untested, controversial, or otherwise unresolved; even the degree to which such a comprehensive theory is possible remains unknown.

25 CFR 82.6 - Petition format.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Petition format. 82.6 Section 82.6 Indians BUREAU OF... REORGANIZED UNDER FEDERAL STATUTE AND OTHER ORGANIZED TRIBES § 82.6 Petition format. Petitions may consist of... of a petition must set forth at least a summary of the objectives of the petitioners and must show...

Spontaneous vesicle formation at lipid bilayer membranes.

PubMed

Edwards, D A; Schneck, F; Zhang, I; Davis, A M; Chen, H; Langer, R

1996-09-01

Unilamellar vesicles are observed to form spontaneously at planar lipid bilayers agitated by exothermic chemical reactions. The membrane-binding reaction between biotin and streptavidin, two strong transmembrane neutralization reactions, and a weak neutralization reaction involving an "antacid" buffer, all lead to spontaneous vesicle formation. This formation is most dramatic when a viscosity differential exists between the two phases bounding the membrane, in which case vesicles appear exclusively in the more viscous phase. A hydrodynamic analysis explains the phenomenon in terms of a membrane flow driven by liberated reaction energy, leading to vesicle formation. These results suggest that energy liberated by intra- and extracellular chemical reactions near or at cell and internal organelle membranes can play an important role in vesicle formation, membrane agitation, or enhanced transmembrane mass transfer.

Sublimation Formation on Mercury

NASA Image and Video Library

2017-12-08

Located in the crater Eminescu, this high-resolution image shows part of the mountainous peak ring, as well as an example of the extensive formation of hollows located within the crater. Hollows maintain an air of mystery in the realm of planetary science. Though the exact formation mechanism is unknown, most scientists agree sublimation of volatiles holds the answer. This image highlights the prevalence of these hollows on and around the peak ring, as well as captures the beauty of such enigmatic formations. This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Objective measurement of complex multimodal and multidimensional display formats: a common metric for predicting format effectiveness

NASA Astrophysics Data System (ADS)

Marshak, William P.; Darkow, David J.; Wesler, Mary M.; Fix, Edward L.

2000-08-01

Computer-based display designers have more sensory modes and more dimensions within sensory modality with which to encode information in a user interface than ever before. This elaboration of information presentation has made measurement of display/format effectiveness and predicting display/format performance extremely difficult. A multivariate method has been devised which isolates critical information, physically measures its signal strength, and compares it with other elements of the display, which act like background noise. This common Metric relates signal-to-noise ratios (SNRs) within each stimulus dimension, then combines SNRs among display modes, dimensions and cognitive factors can predict display format effectiveness. Examples with their Common Metric assessment and validation in performance will be presented along with the derivation of the metric. Implications of the Common Metric in display design and evaluation will be discussed.

Seminary Formation: A Case Study from the Pontifical Beda College, Rome

ERIC Educational Resources Information Center

Strange, Roderick

2015-01-01

This case study account reviews issues related to seminary formation and education at the Beda College, Rome, including Fundamentals of Formation, Community Life, Organizing Formation, Intellectual Formation, Spiritual Formation, Pastoral Formation, and the challenges arising in these fields.

Station-Keeping Strategies for Lead-Trail Formation Flying

NASA Astrophysics Data System (ADS)

Martinot, V.; Rozanes, P.

Numerous projects in the Science and Observation domains involve the use of formation flying to ensure the mission performance. The formation flying configurations proposed in some of them are quite complex with several satellites in different planes generating relative differential motions between the satellites like in case of circular projected formation-flying. However, more simple designs consisting of two satellites in a lead-trail formation appear to be sufficient for a wide range of applications (interferometry, geodesy,...). This article concentrates on the station- keeping phase of such formations in Low-Earth Orbits The station-keeping criterion for such formations can be expressed for example in terms of difference in argument of latitude between both satellites and at the altitudes considered, it evolves mainly under the differential effect of the atmospheric drag between the trailing and leading satellites. In the present paper, this differential effect is supposed to originate from the difference in the area-to-mass ratio between the satellites due to their different designs. A preliminary estimation of the navigation performance is first given assuming that on-board GPS receiver are mounted on each satellite of the formation to acquire pseudo-range measurements between the LEO satellites and the MEO GPS constellation. The distance between both satellites of the formation is derived from independent orbit restitution performed for each LEO satellite in a ground master control station processing the GPS measurements. A strategy for controlling the satellite formation disturbed by the differential effect of the drag is then proposed. Simulations are performed to assess the feasibility of the station-keeping with different types of engines. As by-products, the propellant budget and the frequency of the station-keeping manoeuvres are also given. A case study inspired from the ESA project Acechem/Metop is used for the simulations.

Creating and maintaining a gas cap in tar sands formations

DOEpatents

Vinegar, Harold J.; Karanikas, John Michael; Dinkoruk, Deniz Sumnu; Wellington, Scott Lee

2010-03-16

Methods for treating a tar sands formation are disclosed herein. Methods for treating a tar sands formation may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. Pressure may be allowed to increase in an upper portion of the formation to provide a gas cap in the upper portion. At least some hydrocarbons are produced from a lower portion of the formation.

The accelerating pace of star formation

NASA Astrophysics Data System (ADS)

Caldwell, Spencer; Chang, Philip

2018-03-01

We study the temporal and spatial distribution of star formation rates in four well-studied star-forming regions in local molecular clouds (MCs): Taurus, Perseus, ρ Ophiuchi, and Orion A. Using published mass and age estimates for young stellar objects in each system, we show that the rate of star formation over the last 10 Myr has been accelerating and is (roughly) consistent with a t2 power law. This is in line with previous studies of the star formation history of MCs and with recent theoretical studies. We further study the clustering of star formation in the Orion nebula cluster. We examine the distribution of young stellar objects as a function of their age by computing an effective half-light radius for these young stars subdivided into age bins. We show that the distribution of young stellar objects is broadly consistent with the star formation being entirely localized within the central region. We also find a slow radial expansion of the newly formed stars at a velocity of v = 0.17 km s-1, which is roughly the sound speed of the cold molecular gas. This strongly suggests the dense structures that form stars persist much longer than the local dynamical time. We argue that this structure is quasi-static in nature and is likely the result of the density profile approaching an attractor solution as suggested by recent analytic and numerical analysis.

The formation of stellar black holes

NASA Astrophysics Data System (ADS)

Mirabel, Félix

2017-08-01

It is believed that stellar black holes (BHs) can be formed in two different ways: Either a massive star collapses directly into a BH without a supernova (SN) explosion, or an explosion occurs in a proto-neutron star, but the energy is too low to completely unbind the stellar envelope, and a large fraction of it falls back onto the short-lived neutron star (NS), leading to the delayed formation of a BH. Theoretical models set progenitor masses for BH formation by implosion, namely, by complete or almost complete collapse, but observational evidences have been elusive. Here are reviewed the observational insights on BHs formed by implosion without large natal kicks from: (1) the kinematics in three dimensions of space of five Galactic BH X-ray binaries (BH-XRBs), (2) the diversity of optical and infrared observations of massive stars that collapse in the dark, with no luminous SN explosions, possibly leading to the formation of BHs, and (3) the sources of gravitational waves (GWs) produced by mergers of stellar BHs so far detected with LIGO. Multiple indications of BH formation without ejection of a significant amount of matter and with no natal kicks obtained from these different areas of observational astrophysics, and the recent observational confirmation of the expected dependence of BH formation on metallicity and redshift, are qualitatively consistent with the high merger rates of binary black holes (BBHs) inferred from the first detections with LIGO.

Biological ice nucleation initiates hailstone formation

NASA Astrophysics Data System (ADS)

Michaud, Alexander B.; Dore, John E.; Leslie, Deborah; Lyons, W. Berry; Sands, David C.; Priscu, John C.

2014-11-01

Cloud condensation and ice nuclei in the troposphere are required precursors to cloud and precipitation formation, both of which influence the radiative balance of Earth. The initial stage of hailstone formation (i.e., the embryo) and the subsequent layered growth allow hail to be used as a model for the study of nucleation processes in precipitation. By virtue of the preserved particle and isotopic record captured by hailstones, they represent a unique form of precipitation that allows direct characterization of the particles present during atmospheric ice nucleation. Despite the ecological and economic consequences of hail storms, the dynamics of hailstone nucleation, and thus their formation, are not well understood. Our experiments show that hailstone embryos from three Rocky Mountain storms contained biological ice nuclei capable of freezing water at warm, subzero (°C) temperatures, indicating that biological particles can act as nucleation sites for hailstone formation. These results are corroborated by analysis of δD and δ18O from melted hailstone embryos, which show that the hailstones formed at similarly warm temperatures in situ. Low densities of ice nucleation active abiotic particles were also present in hailstone embryos, but their low concentration indicates they were not likely to have catalyzed ice formation at the warm temperatures determined from water stable isotope analysis. Our study provides new data on ice nucleation occurring at the bottom of clouds, an atmospheric region whose processes are critical to global climate models but which has challenged instrument-based measurements.

The formation of ice sails

NASA Astrophysics Data System (ADS)

Fowler, A. C.; Mayer, C.

2017-11-01

Debris-covered glaciers are prone to the formation of a number of supraglacial geomorphological features, and generally speaking, their upper surfaces are far from level surfaces. Some of these features are due to radiation screening or enhancing properties of the debris cover, but theoretical explanations of the consequent surface forms are in their infancy. In this paper we consider a theoretical model for the formation of "ice sails", which are regularly spaced bare ice features which are found on debris-covered glaciers in the Karakoram.

Is HDF5 a Good Format to Replace UVFITS?

NASA Astrophysics Data System (ADS)

Price, D. C.; Barsdell, B. R.; Greenhill, L. J.

2015-09-01

The FITS (Flexible Image Transport System) data format was developed in the late 1970s for storage and exchange of astronomy-related image data. Since then, it has become a standard file format not only for images, but also for radio interferometer data (e.g. UVFITS, FITS-IDI). But is FITS the right format for next-generation telescopes to adopt? The newer Hierarchical Data Format (HDF5) file format offers considerable advantages over FITS, but has yet to gain widespread adoption within the radio astronomy. One of the major holdbacks is that HDF5 is not well supported by data reduction software packages. Here, we present a comparison of FITS, HDF5, and the MeasurementSet (MS) format for storage of interferometric data. In addition, we present a tool for converting between formats. We show that the underlying data model of FITS can be ported to HDF5, a first step toward achieving wider HDF5 support.

Coordination of FocA and Pyruvate Formate-Lyase Synthesis in Escherichia coli Demonstrates Preferential Translocation of Formate over Other Mixed-Acid Fermentation Products

PubMed Central

Beyer, Lydia; Doberenz, Claudia; Falke, Dörte; Hunger, Doreen; Suppmann, Bernhard

2013-01-01

Enterobacteria such as Escherichia coli generate formate, lactate, acetate, and succinate as major acidic fermentation products. Accumulation of these products in the cytoplasm would lead to uncoupling of the membrane potential, and therefore they must be either metabolized rapidly or exported from the cell. E. coli has three membrane-localized formate dehydrogenases (FDHs) that oxidize formate. Two of these have their respective active sites facing the periplasm, and the other is in the cytoplasm. The bidirectional FocA channel translocates formate across the membrane delivering substrate to these FDHs. FocA synthesis is tightly coupled to synthesis of pyruvate formate-lyase (PflB), which generates formate. In this study, we analyze the consequences on the fermentation product spectrum of altering FocA levels, uncoupling FocA from PflB synthesis or blocking formate metabolism. Changing the focA translation initiation codon from GUG to AUG resulted in a 20-fold increase in FocA during fermentation and an ∼3-fold increase in PflB. Nevertheless, the fermentation product spectrum throughout the growth phase remained similar to that of the wild type. Formate, acetate, and succinate were exported, but only formate was reimported by these cells. Lactate accumulated in the growth medium only in mutants lacking FocA, despite retaining active PflB, or when formate could not be metabolized intracellularly. Together, these results indicate that FocA has a strong preference for formate as a substrate in vivo and not other acidic fermentation products. The tight coupling between FocA and PflB synthesis ensures adequate substrate delivery to the appropriate FDH. PMID:23335413

Kepler Planet Formation

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

2015-01-01

Kepler has vastly increased our knowledge of planets and planetary systems located close to stars. The new data shows surprising results for planetary abundances, planetary spacings and the distribution of planets on a mass-radius diagram. The implications of these results for theories of planet formation will be discussed.

Nitrate formation during ozonation as a surrogate parameter for abatement of micropollutants and the N-nitrosodimethylamine (NDMA) formation potential.

PubMed

Song, Yang; Breider, Florian; Ma, Jun; von Gunten, Urs

2017-10-01

In this study, nitrate formation from ammonium and/or dissolved organic nitrogen (DON) was investigated as a novel surrogate parameter to evaluate the abatement of micropollutants during ozonation of synthetic waters containing natural organic matter (NOM) isolates, a natural water and secondary wastewater effluents. Nitrate formation during ozonation was compared to the changes in UV absorbance at 254 nm (UVA 254 ) including the effect of pH. For low specific ozone doses UVA 254 was abated more efficiently than nitrate was formed. This is due to a relatively slow rate-limiting step for nitrate formation from the reaction between ozone and a proposed nitrogen-containing intermediate. This reaction cannot compete with the fast reactions between ozone and UV-absorbing moieties (e.g., activated aromatic compounds). To further test the kinetics of nitrate formation, two possible intermediates formed during ozonation of DON were tested. At pH 7, nitrate was formed during ozonation of acetone oxime and methyl nitroacetate with second-order rate constants of 256.7 ± 4.7 M -1  s -1 and 149.5 ± 5.8 M -1  s -1 , respectively. The abatement of the selected micropollutants (i.e., 17α-ethinylestradiol (EE2), carbamazepine (CBZ), bezafibrate (BZF), ibuprofen (IBU), and p-chlorobenzoic acid (pCBA)) was investigated for specific ozone doses ≤1.53 mgO 3 /mgDOC and its efficiency depended strongly on the reactivity of the selected compounds with ozone. The relative abatement of micropollutants (i.e., EE2 and CBZ) with high ozone reactivity showed linear relationships with nitrate formation. The abatement of micropollutants with intermediate-low ozone reactivity (BZF, IBU, and pCBA) followed one- and two-phase behaviors relative to nitrate formation during ozonation of water samples containing high and low concentrations of nitrate-forming DON, respectively. During ozonation of a wastewater sample, the N-nitrosodimethylamine formation potential (NDMA-FP) during

String Stability of a Linear Formation Flight Control System

NASA Technical Reports Server (NTRS)

Allen, Michael J.; Ryan, Jack; Hanson, Curtis E.; Parle, James F.

2002-01-01

String stability analysis of an autonomous formation flight system was performed using linear and nonlinear simulations. String stability is a measure of how position errors propagate from one vehicle to another in a cascaded system. In the formation flight system considered here, each i(sup th) aircraft uses information from itself and the preceding ((i-1)(sup th)) aircraft to track a commanded relative position. A possible solution for meeting performance requirements with such a system is to allow string instability. This paper explores two results of string instability and outlines analysis techniques for string unstable systems. The three analysis techniques presented here are: linear, nonlinear formation performance, and ride quality. The linear technique was developed from a worst-case scenario and could be applied to the design of a string unstable controller. The nonlinear formation performance and ride quality analysis techniques both use nonlinear formation simulation. Three of the four formation-controller gain-sets analyzed in this paper were limited more by ride quality than by performance. Formations of up to seven aircraft in a cascaded formation could be used in the presence of light gusts with this string unstable system.

Relative dynamics and motion control of nanosatellite formation flying

NASA Astrophysics Data System (ADS)

Pimnoo, Ammarin; Hiraki, Koju

2016-04-01

Orbit selection is a necessary factor in nanosatellite formation mission design/meanwhile, to keep the formation, it is necessary to consume fuel. Therefore, the best orbit design for nanosatellite formation flying should be one that requires the minimum fuel consumption. The purpose of this paper is to analyse orbit selection with respect to the minimum fuel consumption, to provide a convenient way to estimate the fuel consumption for keeping nanosatellite formation flying and to present a simplified method of formation control. The formation structure is disturbed by J2 gravitational perturbation and other perturbing accelerations such as atmospheric drag. First, Gauss' Variation Equations (GVE) are used to estimate the essential ΔV due to the J2 perturbation and atmospheric drag. The essential ΔV presents information on which orbit is good with respect to the minimum fuel consumption. Then, the linear equations which account for J2 gravitational perturbation of Schweighart-Sedwick are presented and used to estimate the fuel consumption to maintain the formation structure. Finally, the relative dynamics motion is presented as well as a simplified motion control of formation structure by using GVE.

Stratigraphy of the outcropping formations in southern Florida

USGS Publications Warehouse

Schroeder, Melvin Carroll; Hoy, Nevin Douglas

1952-01-01

The geology of southern Florida, except for the Pliocene deposits, is not widely known among geologists and paleontologists. The popular concept is that there are very few outcrops in this part of the State. It is true that there are very few natural exposures, but the dredging of rivers and the construction of canals have made many exposures. The Tamiami formation is the only formation of Miocene age exposed at the surface that is recognized in southwestern Florida. The Hawthorn formation and the older Tertiary formations have been recognized in samples from wells in southern Florida.

Thermodynamics and kinetics of vesicles formation processes.

PubMed

Guida, Vincenzo

2010-12-15

Vesicles are hollow aggregates, composed of bilayers of amphiphilic molecules, dispersed into and filled with a liquid solvent. These aggregates can be formed either as equilibrium or as out of equilibrium meta-stable structures and they exhibit a rich variety of different morphologies. The surprising richness of structures, the vast range of industrial applications and the presence of vesicles in a number of biological systems have attracted the interest of numerous researchers and scientists. In this article, we review both the thermodynamics and the kinetics aspects of the phenomena of formation of vesicles. We start presenting the thermodynamics of bilayer membranes formation and deformation, with the aim of deriving the conditions for the existence of equilibrium vesicles. Specifically, we use the results from continuum thermodynamics to discuss the possibility of formation of stable equilibrium vesicles, from both mixed amphiphiles and single component systems. We also link the bilayer membrane properties to the molecular structure of the starting amphiphiles. In the second part of this article, we focus on the dynamics and kinetics of vesiculation. We review the process of vesicles formation both from planar lamellar phase under shear and from isotropic micelles. In order to clarify the physical mechanisms of vesicles formation, we continuously draw a parallel between emulsification and vesiculation processes. Specifically, we compare the experimental results, the driving forces and the relative scaling laws identified for the two processes. Describing the dynamics of vesicles formation, we also discuss why non equilibrium vesicles can be formed by kinetics control and why they are meta-stable. Understanding how to control the properties, the stability and the formation process of vesicles is of fundamental importance for a vast number of industrial applications. Copyright © 2009. Published by Elsevier B.V.

On-Going Galaxy Formation

NASA Astrophysics Data System (ADS)

Braine, Jonathan; Duc, P.-A.; Lisenfeld, U.; Charmandaris, V.; Vallejo, O.; Leon, S.; Brinks, E.

2002-07-01

We investigate the process of galaxy formation as can be observed in the only currently forming galaxies - the so-called Tidal Dwarf Galaxies, hereafter TDGs - through observations of the molecular gas detected via its CO (Carbon Monoxide) emission. These objects are formed of material torn off of the outer parts of a spiral disk due to tidal forces in a collision between two massive galaxies. Molecular gas is a key element in the galaxy formation process, providing the link between a cloud of gas and a bona fide galaxy. We have detected CO in 8 TDGs (Braine, Lisenfeld, Duc and Leon, 2000: Nature 403, 867; Braine, Duc, Lisenfeld, Charmandaris, Vallejo, Leon and Brinks: 2001, A&A 378, 51), with an overall detection rate of 80%, showing that molecular gas is abundant in TDGs, up to a few 108 M ⊙. The CO emission coincides both spatially and kinematically with the HI emission, indicating that the molecular gas forms from the atomic hydrogen where the HI column density is high. A possible trend of more evolved TDGs having greater molecular gas masses is observed, in accord with the transformation of HI into H2. Although TDGs share many of the properties of small irregulars, their CO luminosity is much greater (factor ˜ 100) than that of standard dwarf galaxies of comparable luminosity. This is most likely a consequence of the higher metallicity (≳sim 1/3 solar) of TDGs which makes CO a good tracer of molecular gas. This allows us to study star formation in environments ordinarily inaccessible due to the extreme difficulty of measuring the molecular gas mass. The star formation efficiency, measured by the CO luminosity per Hα flux, is the same in TDGs and full-sized spirals. CO is likely the best tracer of the dynamics of these objects because some fraction of the HI near the TDGs may be part of the tidal tail and not bound to the TDG. Although uncertainties are large for individual objects, as the geometry is unknown, our sample is now of eight detected objects

RNA-DNA Triplex Formation by Long Noncoding RNAs.

PubMed

Li, Yue; Syed, Junetha; Sugiyama, Hiroshi

2016-11-17

Long noncoding RNAs (lncRNAs) play a pivotal role in the regulation of biological processes through various mechanisms that are not fully understood. Proposed mechanisms include regulation based on RNA-protein interactions, as well as RNA-RNA interactions and RNA-DNA interactions. Here, we focus on one possible mechanism that lncRNA might be using to impact biological function, the RNA-DNA triplex formation. We summarize currently available examples of lncRNA triplex formation and discuss the details surrounding orientation of triplex formation as one of the key properties guiding this process. We propose that symmetrical triplex-forming motifs, especially those in cis-acting lncRNAs, favor triplex formation. We also consider the effects of lncRNA structures, protein or ligand binding, and chromatin structures on the lncRNAs triplex formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Star Formation & the Star Formation History of the Universe: Exploring the X-ray and the Multi-wavelength Point of Views

NASA Astrophysics Data System (ADS)

Burgarella, Denis; Ciesla, Laure; Boquien, Mederic; Buat, Veronique; Roehlly, Yannick

2015-09-01

The star formation rate density traces the formation of stars in the universe. To estimate the star formation rate of galaxies, we can use a wide range of star formation tracers: continuum measurements in most wavelength domains, lines, supernovae and GRBs... All of them have pros and cons. Most of the monochromatic tracers are hampered but the effects of dust. But, before being able to estimate the star formation rate, we first need to obtain a safe estimate to the dust attenuation. The advantage of the X-ray wavelength range is that we can consider it as free from the effect of dust. In this talk, we will estimate how many galaxies we could detect with ATHENA to obtain the star formation density. For this, I will use my recent Herschel paper where the total (UV + IR) star formation rate density was evaluated up to z ~ 4 and provide quantitative figures for what ATHENA will detect as a function of the redshift and the luminosity. ATHENA will need predictions that are in agreement with what we observe in the other wavelength ranges. I will present the code CIGALE (http://cigale.lam.fr). The new and public version of CIGALE (released in April 2015) allows to model the emission of galaxies from the far-ultraviolet to the radio and it can make prediction in any of these wavelength ranges. I will show how galaxy star formation rates can be estimated in a way that combines all the advantages of monochromatic tracers but not the caveats. It should be stressed that we can model the emission of AGNs in the FUV-to-FIR range using several models. Finally, I will explain why we seriously consider to extend CIGALE to the x-ray range to predict the X-ray emission of galaxies including any AGN.

Evolutionary dynamics of group formation.

PubMed

Javarone, Marco Alberto; Marinazzo, Daniele

2017-01-01

Group formation is a quite ubiquitous phenomenon across different animal species, whose individuals cluster together forming communities of diverse size. Previous investigations suggest that, in general, this phenomenon might have similar underlying reasons across the interested species, despite genetic and behavioral differences. For instance improving the individual safety (e.g. from predators), and increasing the probability to get food resources. Remarkably, the group size might strongly vary from species to species, e.g. shoals of fishes and herds of lions, and sometimes even within the same species, e.g. tribes and families in human societies. Here we build on previous theories stating that the dynamics of group formation may have evolutionary roots, and we explore this fascinating hypothesis from a purely theoretical perspective, with a model using the framework of Evolutionary Game Theory. In our model we hypothesize that homogeneity constitutes a fundamental ingredient in these dynamics. Accordingly, we study a population that tries to form homogeneous groups, i.e. composed of similar agents. The formation of a group can be interpreted as a strategy. Notably, agents can form a group (receiving a 'group payoff'), or can act individually (receiving an 'individual payoff'). The phase diagram of the modeled population shows a sharp transition between the 'group phase' and the 'individual phase', characterized by a critical 'individual payoff'. Our results then support the hypothesis that the phenomenon of group formation has evolutionary roots.

In situ oxidation of subsurface formations

DOEpatents

Beer, Gary Lee [Houston, TX; Mo, Weijian [Sugar Land, TX; Li, Busheng [Houston, TX; Shen, Chonghui [Calgary, CA

2011-01-11

Methods and systems for treating a hydrocarbon containing formation described herein include providing heat to a first portion of the formation from a plurality of heaters in the first portion, producing produced through one or more production wells in a second portion of the formation, reducing or turning off heat provided to the first portion after a selected time, providing an oxidizing fluid through one or more of the heater wells in the first portion, providing heat to the first portion and the second portion through oxidation of at least some hydrocarbons in the first portion, and producing fluids through at least one of the production wells in the second portion. The produced fluids may include at least some oxidized hydrocarbons produced in the first portion.

Protostar formation in the early universe.

PubMed

Yoshida, Naoki; Omukai, Kazuyuki; Hernquist, Lars

2008-08-01

The nature of the first generation of stars in the universe remains largely unknown. Observations imply the existence of massive primordial stars early in the history of the universe, and the standard theory for the growth of cosmic structure predicts that structures grow hierarchically through gravitational instability. We have developed an ab initio computer simulation of the formation of primordial stars that follows the relevant atomic and molecular processes in a primordial gas in an expanding universe. The results show that primeval density fluctuations left over from the Big Bang can drive the formation of a tiny protostar with a mass 1% that of the Sun. The protostar is a seed for the subsequent formation of a massive primordial star.

Methanol toxicity and formate oxidation in NEUT2 mice.

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

Cook, R. J.; Champion, K. M.; Giometti, C. S.

2001-09-15

NEUT2 mice are deficient in cytosolic 10-formyltetrahydrofolate dehydrogenase (FDH; EC 1.5.1.6) which catalyzes the oxidation of excess folate-linked one-carbon units in the form of 10-formyltetrahydrofolate to CO{sub 2} and tetrahydrofolate. The absence of FDH should impair the oxidation of formate via the folate-dependent pathway and as a consequence render homozygous NEUT2 mice more susceptible to methanol toxicity. Normal (CB6-F1) and NEUT2 heterozygous and homozygous mice had essentially identical LD50 values for methanol, 6.08, 6.00, and 6.03 g/kg, respectively. Normal mice oxidized low doses of [{sup 14}C]sodium formate (ip 5 mg/kg) to {sup 14}CO{sub 2} at approximately twice the rate ofmore » homozygous NEUT2 mice, indicating the presence of another formate-oxidizing system in addition to FDH. Treatment of mice with the catalase inhibitor, 3-aminotriazole (1 g/kg ip) had no effect on the rate of formate oxidation, indicating that at low concentrations formate was not oxidized peroxidatively by catalase. High doses of [{sup 14}C]sodium formate (ip 100 mg/kg) were oxidized to {sup 14}CO{sub 2} at identical rates in normal and NEUT2 homozygous mice. Pretreatment with 3-aminotriazole (1 g/kg ip) in this instance resulted in a 40 and 50% decrease in formate oxidation to CO2 in both normal and homozygous NEUT2 mice, respectively. These results indicate that mice are able to oxidize formate to CO{sub 2} by at least three different routes: (1) folate-dependent via FDH at low levels of formate; (2) peroxidation by catalase at high levels of formate; and (3) by an unknown route(s) which appears to function at both low and high levels of formate. The implications of these observations are discussed in terms of the current hypotheses concerning methanol and formate toxicity in rodents and primates.« less

Promoting proximal formative assessment with relational discourse

NASA Astrophysics Data System (ADS)

Scherr, Rachel E.; Close, Hunter G.; McKagan, Sarah B.

2012-02-01

The practice of proximal formative assessment - the continual, responsive attention to students' developing understanding as it is expressed in real time - depends on students' sharing their ideas with instructors and on teachers' attending to them. Rogerian psychology presents an account of the conditions under which proximal formative assessment may be promoted or inhibited: (1) Normal classroom conditions, characterized by evaluation and attention to learning targets, may present threats to students' sense of their own competence and value, causing them to conceal their ideas and reducing the potential for proximal formative assessment. (2) In contrast, discourse patterns characterized by positive anticipation and attention to learner ideas increase the potential for proximal formative assessment and promote self-directed learning. We present an analysis methodology based on these principles and demonstrate its utility for understanding episodes of university physics instruction.

Star formation and extinct radioactivities

NASA Technical Reports Server (NTRS)

Cameron, A. G. W.

1984-01-01

An assessment is made of the evidence for the existence of now-extinct radioactivities in primitive solar system material, giving attention to implications for the early stages of sun and solar system formation. The characteristics of possible disturbances in dense molecular clouds which can initiate the formation of cloud cores is discussed, with emphasis on these disturbances able to generate fresh radioactivities. A one-solar mass red giant star on the asymptotic giant branch appears to have been the best candidate to account for the short-lived extinct radioactivities in the early solar system.

Three-dimensional laser window formation

NASA Technical Reports Server (NTRS)

Verhoff, Vincent G.

1992-01-01

The NASA Lewis Research Center has developed and implemented a unique process for forming flawless three-dimensional laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report discusses in detail the aspects of three-dimensional laser window formation. It focuses on the unique methodology and the peculiarities associated with the formation of these windows. Included in this discussion are the design criteria, bonding mediums, and evaluation testing for three-dimensional laser windows.

Silicide formation process of Pt added Ni at low temperature: Control of NiSi2 formation

NASA Astrophysics Data System (ADS)

Ikarashi, Nobuyuki; Masuzaki, Koji

2011-03-01

Transmission electron microscopy (TEM) and ab initio calculations revealed that the Ni-Si reaction around 300 °C is significantly changed by adding Pt to Ni. TEM analysis clarified that NiSi2 was formed in a reaction between Ni thin film (˜1 nm) and Si substrate, while NiSi was formed when Pt was added to the Ni film. We also found that the Ni-adamantane structure, which acts as a precursor for NiSi2 formation around the reaction temperature, was formed in the former reaction but was significantly suppressed in the latter reaction. Theoretical calculations indicated that Pt addition increased stress at the Ni-adamantane structure/Si-substrate interface. The increase in interface stress caused by Pt addition should raise the interface energy to suppress the Ni-adamantane structure formation, leading to NiSi2 formation being suppressed.

Reconsidering Formative Measurement

ERIC Educational Resources Information Center

Howell, Roy D.; Breivik, Einar; Wilcox, James B.

2007-01-01

The relationship between observable responses and the latent constructs they are purported to measure has received considerable attention recently, with particular focus on what has become known as formative measurement. This alternative to reflective measurement in the area of theory-testing research is examined in the context of the potential…

Detergent-Mediated Formation of β-Hematin: Heme Crystallization Promoted by Detergents Implicates Nanostructure Formation for Use as a Biological Mimic

PubMed Central

2016-01-01

Hemozoin is a unique biomineral that results from the sequestration of toxic free heme liberated as a consequence of hemoglobin degradation in the malaria parasite. Synthetic neutral lipid droplets (SNLDs) and phospholipids were previously shown to support the rapid formation of β-hematin, abiological hemozoin, under physiologically relevant pH and temperature, though the mechanism by which heme crystallization occurs remains unclear. Detergents are particularly interesting as a template because they are amphiphilic molecules that spontaneously organize into nanostructures and have been previously shown to mediate β-hematin formation. Here, 11 detergents were investigated to elucidate the physicochemical properties that best recapitulate crystal formation in the parasite. A strong correlation between the detergent’s molecular structure and the corresponding kinetics of β-hematin formation was observed, where higher molecular weight polar chains promoted faster reactions. The larger hydrophilic chains correlated to the detergent’s ability to rapidly sequester heme into the lipophilic core, allowing for crystal nucleation to occur. The data presented here suggest that detergent nanostructures promote β-hematin formation in a similar manner to SNLDs and phospholipids. Through understanding mediator properties that promote optimal crystal formation, we are able to establish an in vitro assay to probe this drug target pathway. PMID:27175104

Formation and Assembly of Massive Star Clusters

NASA Astrophysics Data System (ADS)

McMillan, Stephen

The formation of stars and star clusters is a major unresolved problem in astrophysics. It is central to modeling stellar populations and understanding galaxy luminosity distributions in cosmological models. Young massive clusters are major components of starburst galaxies, while globular clusters are cornerstones of the cosmic distance scale and represent vital laboratories for studies of stellar dynamics and stellar evolution. Yet how these clusters form and how rapidly and efficiently they expel their natal gas remain unclear, as do the consequences of this gas expulsion for cluster structure and survival. Also unclear is how the properties of low-mass clusters, which form from small-scale instabilities in galactic disks and inform much of our understanding of cluster formation and star-formation efficiency, differ from those of more massive clusters, which probably formed in starburst events driven by fast accretion at high redshift, or colliding gas flows in merging galaxies. Modeling cluster formation requires simulating many simultaneous physical processes, placing stringent demands on both software and hardware. Simulations of galaxies evolving in cosmological contexts usually lack the numerical resolution to simulate star formation in detail. They do not include detailed treatments of important physical effects such as magnetic fields, radiation pressure, ionization, and supernova feedback. Simulations of smaller clusters include these effects, but fall far short of the mass of even single young globular clusters. With major advances in computing power and software, we can now directly address this problem. We propose to model the formation of massive star clusters by integrating the FLASH adaptive mesh refinement magnetohydrodynamics (MHD) code into the Astrophysical Multi-purpose Software Environment (AMUSE) framework, to work with existing stellar-dynamical and stellar evolution modules in AMUSE. All software will be freely distributed on-line, allowing

Cu(II) promotes amyloid pore formation

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

Zhang, Hangyu, E-mail: hangyuz@uw.edu; Rochet, Jean-Christophe; Stanciu, Lia A.

2015-08-14

The aggregation of α-synuclein is associated with dopamine neuron death in Parkinson's disease. There is controversy in the field over the question of which species of the aggregates, fibrils or protofibrils, are toxic. Moreover, compelling evidence suggested the exposure to heavy metals to be a risk of PD. Nevertheless, the mechanism of metal ions in promoting PD remains unclear. In this research, we investigated the structural basis of Cu(II) induced aggregation of α-synuclein. Using transmission electron microscopy experiments, Cu(II) was found to promote in vitro aggregation of α-synuclein by facilitating annular protofibril formation rather than fibril formation. Furthermore, neuroprotective baicalein disaggregatedmore » annular protofibrils accompanied by considerable decrease of β-sheet content. These results strongly support the hypothesis that annular protofibrils are the toxic species, rather than fibrils, thereby inspiring us to search novel therapeutic strategies for the suppression of the toxic annular protofibril formation. - Highlights: • Cu(II) promoted the annular protofibril formation of α-synuclein in vitro. • Cu(II) postponed the in vitro fibrillization of α-synuclein. • Neuroprotective baicalein disaggregated annular protofibrils.« less

Molecular Genetics of Supernumerary Tooth Formation

PubMed Central

Wang, Xiu-Ping; Fan, Jiabing

2011-01-01

Summary Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/β(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering. PMID:21309064

Transcriptional regulation of Drosophila gonad formation.

PubMed

Tripathy, Ratna; Kunwar, Prabhat S; Sano, Hiroko; Renault, Andrew D

2014-08-15

The formation of the Drosophila embryonic gonad, involving the fusion of clusters of somatic gonadal precursor cells (SGPs) and their ensheathment of germ cells, provides a simple and genetically tractable model for the interplay between cells during organ formation. In a screen for mutants affecting gonad formation we identified a SGP cell autonomous role for Midline (Mid) and Longitudinals lacking (Lola). These transcriptional factors are required for multiple aspects of SGP behaviour including SGP cluster fusion, germ cell ensheathment and gonad compaction. The lola locus encodes more than 25 differentially spliced isoforms and we have identified an isoform specific requirement for lola in the gonad which is distinct from that in nervous system development. Mid and Lola work in parallel in gonad formation and surprisingly Mid overexpression in a lola background leads to additional SGPs at the expense of fat body cells. Our findings support the idea that although the transcription factors required by SGPs can ostensibly be assigned to those being required for either SGP specification or behaviour, they can also interact to impinge on both processes. Copyright © 2014 Elsevier Inc. All rights reserved.

Solution mining dawsonite from hydrocarbon containing formations with a chelating agent

DOEpatents

Vinegar, Harold J [Bellaire, TX

2009-07-07

A method for treating an oil shale formation comprising dawsonite includes providing heat from one or more heaters to the formation to heat the formation. Hydrocarbon fluids are produced from the formation. At least some dawsonite in the formation is decomposed with the provided heat. A chelating agent is provided to the formation to dissolve at least some dawsonite decomposition products. The dissolved dawsonite decomposition products are produced from the formation.

Solid-state graphene formation via a nickel carbide intermediate phase [Nickel carbide (Ni 3C) as an intermediate phase for graphene formation

DOE PAGES

Xiong, W; Zhou, Yunshen; Hou, Wenjia; ...

2015-11-10

Direct formation of graphene with controlled number of graphitic layers on dielectric surfaces is highly desired for practical applications. Despite significant progress achieved in understanding the formation of graphene on metallic surfaces through chemical vapor deposition (CVD) of hydrocarbons, very limited research is available elucidating the graphene formation process via rapid thermal processing (RTP) of solid-state amorphous carbon, through which graphene is formed directly on dielectric surfaces accompanied by autonomous nickel evaporation. It is suggested that a metastable hexagonal nickel carbide (Ni 3C) intermediate phase plays a critical role in transforming amorphous carbon to 2D crystalline graphene and contributing tomore » the autonomous Ni evaporation. Temperature resolved carbon and nickel evolution in the RTP process is investigated using Auger electron spectroscopic (AES) depth profiling and glancing-angle X-ray diffraction (GAXRD). Formation, migration and decomposition of the hexagonal Ni 3C are confirmed to be responsible for the formation of graphene and the evaporation of Ni at 1100 °C. The Ni 3C-assisted graphene formation mechanism expands the understanding of Ni-catalyzed graphene formation, and provides insightful guidance for controlled growth of graphene through the solid-state transformation process.« less

Star Formation in NGC 4631

NASA Astrophysics Data System (ADS)

Smith, A. M.; Collins, N. R.; Bohlin, R.; Fanelli, M. N.; Neff, S. G.; O'Connell, R. W.; Roberts, M. S.; Stecher, T. P.; Waller, W. H.

1997-12-01

The group of galaxies including NGC 4631 provides an outstanding example of a galaxy interaction accompanied by intensive star formation. FUV imagery, recorded by the Ultraviolet Imaging Telescope (UIT), exhibits very bright far- ultraviolet (FUV) emission corresponding to the H II regions cataloged by Crillon and Monet (1969). This data is, in our experience, extraordinary in that NCG 4631 is observed nearly edge-on and strong attenuation of FUV light could be anticipated. Analysis of the ultraviolet imagery together with ground-based data leads to the following conclusions. The average extinction internal to the bright FUV regions is low [E(B--V) = 0.31], which combined with the optical morphology implies that the FUV bright regions are close to the edge of the galactic disk. The FUV luminosity of that part of the galaxy which can be observed is 8.2 x 10(40) ergs/s and is about a factor 6 less than the FUV luminosities of M101 and M83. FUV colors, M152-U, M152-B and M152-V, when compared to the predicted colors from cluster formation models utilizing a Salpeter IMF imply an internal extinction like that of a non-30Dor LMC extinction curve (Fitzpatrick 1985). Instantaneous burst models indicate an average age of the FUV bright regions of about 6 Myr and a total created stellar mass of 2.8 x 10(7) Msun . If the measured colors are compared to continuous star formation models, star formation beginning about 100 Myr in the past and continuing to the present with a total star formation rate in the FUV bright regions of 0.026 Msun /yr is implied. The total number of OB stars in the H II regions comprising the large ring in the eastern part of the galaxy (Rand's Shell #1, 1993) is inferred to be 20,000. This number can be compared to Rand's estimate of 10,000 to 35,000 supernova-producing OB stars which are required to impart momentum to an expanding shell of hydrogen gas.

Cytochrome c oxidase inhibition in the rice weevil Sitophilus oryzae (L.) by formate, the toxic metabolite of volatile alkyl formates.

PubMed

Haritos, V S; Dojchinov, G

2003-10-01

Volatile alkyl formates are potential replacements for the ozone-depleting fumigant, methyl bromide, as postharvest insecticides and here we have investigated their mode of insecticidal action. Firstly, a range of alkyl esters, ethanol and formic acid were tested in mortality bioassays with adults of the rice weevil, Sitophilus oryzae (L.) and the grain borer, Rhyzopertha dominica (F.) to determine whether the intact ester or one of its components was the toxic moiety. Volatile alkyl formates and formic acid caused similar levels of mortality (LC(50) 131-165 micromol l(-1)) to S. oryzae and were more potent than non-formate containing alkyl esters and ethanol (LC(50)>275 micromol l(-1)). The order of potency was the same in R. dominica. Ethyl formate was rapidly metabolised in vitro to formic acid when incubated with insect homogenates, presumably through the action of esterases. S. oryzae and R. dominica fumigated with a lethal dose of ethyl formate had eight and 17-fold higher concentrations of formic acid, respectively, in their bodies than untreated controls. When tested against isolated mitochondria from S. oryzae, alkyl esters, alcohols, acetate and propionate salts were not inhibitory towards cytochrome c oxidase (EC 1.9.3.1), but sodium cyanide and sodium formate were inhibitory with IC(50) values of 0.0015 mM and 59 mM, respectively. Volatile formate esters were more toxic than other alkyl esters, and this was found to be due, at least in part, to their hydrolysis to formic acid and its inhibition of cytochrome c oxidase.

Massive Star Formation Viewed through Extragalactic-Tinted Glasses

NASA Astrophysics Data System (ADS)

Willis, Sarah; Marengo, M.; Smith, H. A.; Allen, L.

2014-01-01

Massive Galactic star forming regions are the local analogs to the luminous star forming regions that dominate the emission from star forming galaxies. Their proximity to us enables the characterization of the full range of stellar masses that form in these more massive environments, improving our understanding of star formation tracers used in extragalactic studies. We have surveyed a sample of massive star forming regions with a range of morphologies and luminosities to probe the star formation activity in a variety of environments. We have used Spitzer IRAC and deep ground based J, H, Ks observations to characterize the Young Stellar Object (YSO) content of 6 massive star forming regions. These YSOs provide insight into the rate and efficiency of star formation within these regions, and enable comparison with nearby, low mass star forming regions as well as extreme cases of Galactic star formation including ‘mini-starburst’ regions. In addition, we have conducted an in-depth analysis of NGC 6334 to investigate how the star formation activity varies within an individual star forming region, using Herschel data in the far-infrared to probe the earliest stages of the ongoing star formation activity.

Black-hole-regulated star formation in massive galaxies.

PubMed

Martín-Navarro, Ignacio; Brodie, Jean P; Romanowsky, Aaron J; Ruiz-Lara, Tomás; van de Ven, Glenn

2018-01-18

Supermassive black holes, with masses more than a million times that of the Sun, seem to inhabit the centres of all massive galaxies. Cosmologically motivated theories of galaxy formation require feedback from these supermassive black holes to regulate star formation. In the absence of such feedback, state-of-the-art numerical simulations fail to reproduce the number density and properties of massive galaxies in the local Universe. There is, however, no observational evidence of this strongly coupled coevolution between supermassive black holes and star formation, impeding our understanding of baryonic processes within galaxies. Here we report that the star formation histories of nearby massive galaxies, as measured from their integrated optical spectra, depend on the mass of the central supermassive black hole. Our results indicate that the black-hole mass scales with the gas cooling rate in the early Universe. The subsequent quenching of star formation takes place earlier and more efficiently in galaxies that host higher-mass central black holes. The observed relation between black-hole mass and star formation efficiency applies to all generations of stars formed throughout the life of a galaxy, revealing a continuous interplay between black-hole activity and baryon cooling.

Black-hole-regulated star formation in massive galaxies

NASA Astrophysics Data System (ADS)

Martín-Navarro, Ignacio; Brodie, Jean P.; Romanowsky, Aaron J.; Ruiz-Lara, Tomás; van de Ven, Glenn

2018-01-01

Supermassive black holes, with masses more than a million times that of the Sun, seem to inhabit the centres of all massive galaxies. Cosmologically motivated theories of galaxy formation require feedback from these supermassive black holes to regulate star formation. In the absence of such feedback, state-of-the-art numerical simulations fail to reproduce the number density and properties of massive galaxies in the local Universe. There is, however, no observational evidence of this strongly coupled coevolution between supermassive black holes and star formation, impeding our understanding of baryonic processes within galaxies. Here we report that the star formation histories of nearby massive galaxies, as measured from their integrated optical spectra, depend on the mass of the central supermassive black hole. Our results indicate that the black-hole mass scales with the gas cooling rate in the early Universe. The subsequent quenching of star formation takes place earlier and more efficiently in galaxies that host higher-mass central black holes. The observed relation between black-hole mass and star formation efficiency applies to all generations of stars formed throughout the life of a galaxy, revealing a continuous interplay between black-hole activity and baryon cooling.

Photochemical Formation of Sulfur-Containing Aerosols

NASA Astrophysics Data System (ADS)

Kroll, Jay A.; Vaida, Veronica

2017-06-01

In order to understand planetary climate systems, modeling the properties of atmospheric aerosols is vital. Aerosol formation plays an important role in planetary climates and is tied to feedback loops that can either warm or cool a planet. Sulfur compounds are known to play an important role in new particle aerosol formation and have been observed in a number of planetary atmospheres throughout our solar system. Our current understanding of sulfur chemistry explains much of what we observe in Earth's atmosphere; however, several discrepancies arise when comparing observations of the Venusian atmosphere with model predictions. This suggests that there are still problems in our fundamental understanding of sulfur chemistry. This is concerning given recent renewed interest in sulfate injections in the stratosphere for solar radiation management geo-engineering schemes. We investigate the role of sunlight as a potential driver of the formation of sulfur-containing aerosols. I will present recent work investigating the generation of large quantities of aerosol from the irradiation of mixtures of SO_2 with water and organic species, using a solar simulator that mimics the light that is available in the Earth's troposphere and the Venusian middle atmosphere. I will present on recent work done in our lab suggesting the formation of sulfurous acid, H_2SO_3, and describe experimental work that supports this proposed mechanism. Additionally I will present on new work showing the highly reactive nature of electronically excited SO_2 with saturated alkane species. The implications of this photochemically induced sulfur aerosol formation in the atmosphere of Earth and other planetary atmospheres will be discussed.

Planet Formation in Binary Star Systems

NASA Astrophysics Data System (ADS)

Martin, Rebecca

About half of observed exoplanets are estimated to be in binary systems. Understanding planet formation and evolution in binaries is therefore essential for explaining observed exoplanet properties. Recently, we discovered that a highly misaligned circumstellar disk in a binary system can undergo global Kozai-Lidov (KL) oscillations of the disk inclination and eccentricity. These oscillations likely have a significant impact on the formation and orbital evolution of planets in binary star systems. Planet formation by core accretion cannot operate during KL oscillations of the disk. First, we propose to consider the process of disk mass transfer between the binary members. Secondly, we will investigate the possibility of planet formation by disk fragmentation. Disk self gravity can weaken or suppress the oscillations during the early disk evolution when the disk mass is relatively high for a narrow range of parameters. Thirdly, we will investigate the evolution of a planet whose orbit is initially aligned with respect to the disk, but misaligned with respect to the orbit of the binary. We will study how these processes relate to observations of star-spin and planet orbit misalignment and to observations of planets that appear to be undergoing KL oscillations. Finally, we will analyze the evolution of misaligned multi-planet systems. This theoretical work will involve a combination of analytic and numerical techniques. The aim of this research is to shed some light on the formation of planets in binary star systems and to contribute to NASA's goal of understanding of the origins of exoplanetary systems.

TEMPORAL SELF-ORGANIZATION IN GALAXY FORMATION

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

Cen, Renyue, E-mail: cen@astro.princeton.edu

We report on the discovery of a relation between the number of star formation (SF) peaks per unit time, ν{sub peak}, and the size of the temporal smoothing window function, Δt, used to define the peaks: ν{sub peak}∝Δt {sup 1} {sup –} {sup φ} (φ ∼ 1.618). This relation holds over the range of Δt = 10-1000 Myr that can be reliably computed here, using a large sample of galaxies obtained from a state-of-the-art cosmological hydrodynamic simulation. This means that the temporal distribution of SF peaks in galaxies as a population is fractal with a Hausdorff fractal dimension equal to φmore » – 1. This finding reveals, for the first time, that the superficially chaotic process of galaxy formation is underlined by temporal self-organization up to at least one gigayear. It is tempting to suggest that, given the known existence of spatial fractals (such as the power-law two-point function of galaxies), there is a joint spatio-temporal self-organization in galaxy formation. From an observational perspective, it will be urgent to devise diagnostics to probe the SF histories of galaxies with good temporal resolution to facilitate a test of this prediction. If confirmed, it would provide unambiguous evidence for a new picture of galaxy formation that is interaction driven, cooperative, and coherent in and between time and space. Unravelling its origin may hold the key to understanding galaxy formation.« less

Cloud Optimized Image Format and Compression

NASA Astrophysics Data System (ADS)

Becker, P.; Plesea, L.; Maurer, T.

2015-04-01

Cloud based image storage and processing requires revaluation of formats and processing methods. For the true value of the massive volumes of earth observation data to be realized, the image data needs to be accessible from the cloud. Traditional file formats such as TIF and NITF were developed in the hay day of the desktop and assumed fast low latency file access. Other formats such as JPEG2000 provide for streaming protocols for pixel data, but still require a server to have file access. These concepts no longer truly hold in cloud based elastic storage and computation environments. This paper will provide details of a newly evolving image storage format (MRF) and compression that is optimized for cloud environments. Although the cost of storage continues to fall for large data volumes, there is still significant value in compression. For imagery data to be used in analysis and exploit the extended dynamic range of the new sensors, lossless or controlled lossy compression is of high value. Compression decreases the data volumes stored and reduces the data transferred, but the reduced data size must be balanced with the CPU required to decompress. The paper also outlines a new compression algorithm (LERC) for imagery and elevation data that optimizes this balance. Advantages of the compression include its simple to implement algorithm that enables it to be efficiently accessed using JavaScript. Combing this new cloud based image storage format and compression will help resolve some of the challenges of big image data on the internet.

Particle Formation and Product Formulation Using Supercritical Fluids.

PubMed

Knez, Željko; Knez Hrnčič, Maša; Škerget, Mojca

2015-01-01

Traditional methods for solids processing involve either high temperatures, necessary for melting or viscosity reduction, or hazardous organic solvents. Owing to the negative impact of the solvents on the environment, especially on living organisms, intensive research has focused on new, sustainable methods for the processing of these substances. Applying supercritical fluids for particle formation may produce powders and composites with special characteristics. Several processes for formation and design of solid particles using dense gases have been studied intensively. The unique thermodynamic and fluid-dynamic properties of supercritical fluids can be used also for impregnation of solid particles or for the formation of solid powderous emulsions and particle coating, e.g., for formation of solids with unique properties for use in different applications. We give an overview of the application of sub- and supercritical fluids as green processing media for particle formation processes and present recent advances and trends in development.

Hydrogen or formate: Alternative key players in methanogenic degradation.

PubMed

Schink, Bernhard; Montag, Dominik; Keller, Anja; Müller, Nicolai

2017-06-01

Hydrogen and formate are important electron carriers in methanogenic degradation in anoxic environments such as sediments, sewage sludge digestors and biogas reactors. Especially in the terminal steps of methanogenesis, they determine the energy budgets of secondary (syntrophically) fermenting bacteria and their methanogenic partners. The literature provides considerable data on hydrogen pool sizes in such habitats, but little data exist for formate concentrations due to technical difficulties in formate determination at low concentration. Recent evidence from biochemical and molecular biological studies indicates that several secondary fermenters can use both hydrogen and formate for electron release, and may do so even simultaneously. Numerous strictly anaerobic bacteria contain enzymes which equilibrate hydrogen and formate pools to energetically equal values, and recent measurements in sewage digestors and biogas reactors indicate that - beyond occasional fluctuations - the pool sizes of hydrogen and formate are indeed energetically nearly equivalent. Nonetheless, a thermophilic archaeon from a submarine hydrothermal vent, Thermococcus onnurineus, can obtain ATP from the conversion of formate to hydrogen plus bicarbonate at 80°C, indicating that at least in this extreme environment the pools of formate and hydrogen are likely to be sufficiently different to support such an unusual type of energy conservation. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

ON THE LIKELIHOOD OF PLANET FORMATION IN CLOSE BINARIES

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

Jang-Condell, Hannah, E-mail: hjangcon@uwyo.edu

2015-02-01

To date, several exoplanets have been discovered orbiting stars with close binary companions (a ≲ 30 AU). The fact that planets can form in these dynamically challenging environments implies that planet formation must be a robust process. The initial protoplanetary disks in these systems from which planets must form should be tidally truncated to radii of a few AU, which indicates that the efficiency of planet formation must be high. Here, we examine the truncation of circumstellar protoplanetary disks in close binary systems, studying how the likelihood of planet formation is affected over a range of disk parameters. If themore » semimajor axis of the binary is too small or its eccentricity is too high, the disk will have too little mass for planet formation to occur. However, we find that the stars in the binary systems known to have planets should have once hosted circumstellar disks that were capable of supporting planet formation despite their truncation. We present a way to characterize the feasibility of planet formation based on binary orbital parameters such as stellar mass, companion mass, eccentricity, and semimajor axis. Using this measure, we can quantify the robustness of planet formation in close binaries and better understand the overall efficiency of planet formation in general.« less

What drives the formation of massive stars and clusters?

NASA Astrophysics Data System (ADS)

Ochsendorf, Bram; Meixner, Margaret; Roman-Duval, Julia; Evans, Neal J., II; Rahman, Mubdi; Zinnecker, Hans; Nayak, Omnarayani; Bally, John; Jones, Olivia C.; Indebetouw, Remy

2018-01-01

Galaxy-wide surveys allow to study star formation in unprecedented ways. In this talk, I will discuss our analysis of the Large Magellanic Cloud (LMC) and the Milky Way, and illustrate how studying both the large and small scale structure of galaxies are critical in addressing the question: what drives the formation of massive stars and clusters?I will show that ‘turbulence-regulated’ star formation models do not reproduce massive star formation properties of GMCs in the LMC and Milky Way: this suggests that theory currently does not capture the full complexity of star formation on small scales. I will also report on the discovery of a massive star forming complex in the LMC, which in many ways manifests itself as an embedded twin of 30 Doradus: this may shed light on the formation of R136 and 'Super Star Clusters' in general. Finally, I will highlight what we can expect in the next years in the field of star formation with large-scale sky surveys, ALMA, and our JWST-GTO program.

3D vortex formation of drag-based propulsors

NASA Astrophysics Data System (ADS)

Kim, Daegyoum; Gharib, Morteza

2008-11-01

Three dimensional vortex formation mechanism of impulsively rotating plates is studied experimentally using defocusing digital particle image velocimetry. The plate face is normal to the moving direction to simulate drag-based propulsion and only one power stroke is considered. In order to compare the effect of shape on vortex generation, three different shapes of plate (rectangular, triangular and duck's webbed-foot shapes) are used. These three cases show striking differences in vortex formation process during power stroke. Axial flow is shown to play an important role in the tip vortex formation. Correlation between hydrodynamic forces acting on the plate and vortex formation processes is described.

Formate Assimilation: The Metabolic Architecture of Natural and Synthetic Pathways.

PubMed

Bar-Even, Arren

2016-07-19

Formate may become an ideal mediator between the physicochemical and biological realms, as it can be produced efficiently from multiple available sources, such as electricity and biomass, and serve as one of the simplest organic compounds for providing both carbon and energy to living cells. However, limiting the realization of formate as a microbial feedstock is the low diversity of formate-fixing enzymes and thereby the small number of naturally occurring formate-assimilation pathways. Here, the natural enzymes and pathways supporting formate assimilation are presented and discussed together with proposed synthetic routes that could permit growth on formate via existing as well as novel formate-fixing reactions. By considering such synthetic routes, the diversity of metabolic solutions for formate assimilation can be expanded dramatically, such that different host organisms, cultivation conditions, and desired products could be matched with the most suitable pathway. Astute application of old and new formate-assimilation pathways may thus become a cornerstone in the development of sustainable strategies for microbial production of value-added chemicals.

The formation of stellar systems from interstellar molecular clouds

NASA Technical Reports Server (NTRS)

Gehrz, R. D.; Black, D. C.; Solomon, P.M.

1984-01-01

The observational and theoretical study of regions of continuing star formation promises greater insight into the physical conditions and events associated with the formation of the solar system, and elucidates the role played by star formation in the evolutionary cycle which seems to dominate interstellar material's processing by successive generations of stars in the spiral galaxies. Novel astronomical methods incorporated by the new facilities scheduled for development in the 1980s may yield substantial advancements in star formation process theory; most significant among these efforts will be the identification and examination of the elusive protostellar collapse phase of both star and planetary system formation.

Formation stability analysis of unmanned multi-vehicles under interconnection topologies

NASA Astrophysics Data System (ADS)

Yang, Aolei; Naeem, Wasif; Fei, Minrui

2015-04-01

In this paper, the overall formation stability of an unmanned multi-vehicle is mathematically presented under interconnection topologies. A novel definition of formation error is first given and followed by the proposed formation stability hypothesis. Based on this hypothesis, a unique extension-decomposition-aggregation scheme is then employed to support the stability analysis for the overall multi-vehicle formation under a mesh topology. It is proved that the overall formation control system consisting of N number of nonlinear vehicles is not only asymptotically stable, but also exponentially stable in the sense of Lyapunov within a neighbourhood of the desired formation. This technique is shown to be applicable for a mesh topology but is equally applicable for other topologies. A simulation study of the formation manoeuvre of multiple Aerosonde UAVs (unmanned aerial vehicles), in 3-D space, is finally carried out verifying the achieved formation stability result.

Bonded exciplex formation: electronic and stereoelectronic effects.

PubMed

Wang, Yingsheng; Haze, Olesya; Dinnocenzo, Joseph P; Farid, Samir; Farid, Ramy S; Gould, Ian R

2008-12-18

As recently proposed, the singlet-excited states of several cyanoaromatics react with pyridine via bonded-exciplex formation, a novel concept in photochemical charge transfer reactions. Presented here are electronic and steric effects on the quenching rate constants, which provide valuable support for the model. Additionally, excited-state quenching in poly(vinylpyridine) is strongly inhibited both relative to that in neat pyridine and also to conventional exciplex formation in polymers, consistent with a restrictive orientational requirement for the formation of bonded exciplexes. Examples of competing reactions to form both conventional and bonded exciplexes are presented, which illustrate the delicate balance between these two processes when their reaction energetics are similar. Experimental and computational evidence is provided for the formation of a bonded exciplex in the reaction of the singlet excited state of 2,6,9,10-tetracyanoanthracene (TCA) with an oxygen-substituted donor, dioxane, thus expanding the scope of bonded exciplexes.

Microwave-induced formation of oligomeric amyloid aggregates.

PubMed

Lee, Wonseok; Choi, Yeseong; Lee, Sang Won; Kim, Insu; Lee, Dongtak; Hong, Yoochan; Lee, Gyudo; Yoon, Dae Sung

2018-08-24

Amyloid aggregates have emerged as a significant hallmark of neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Although it has been recently reported that microwave heating induces amyloid aggregation compared with conventional heating methods, the mechanism of amyloid aggregate induction has remained unclear. In this study, we investigated the formation of oligomeric amyloid aggregates (OAAs) by microwave irradiation at microscale volumes of solution. Microwave irradiation of protein monomer solution triggered rapid formation of OAAs within 7 min. We characterized the formation of OAAs using atomic force microscopy, thioflavin T fluorescent assay and circular dichroism. In the microwave system, we also investigated the inhibitory effect on the formation of amyloid aggregates by L-ascorbic acid as well as enhanced amyloid aggregation by silver nanomaterials such as nanoparticles and nanowires. We believe that microwave technology has the potential to facilitate the study of amyloid aggregation in the presence of chemical agents or nanomaterials.

Evidence for arrested bone formation during spaceflight

NASA Technical Reports Server (NTRS)

Turner, R. T.; Bobyn, J. D.; Duvall, P.; Morey, E. R.; Baylink, D. J.; Spector, M.

1982-01-01

Addressing the question of whether the bone formed in space is unusual, the morphology of bone made at the tibial diaphysis of rats before, during, and after spaceflight is studied. Evidence of arrest lines in the bone formed in space is reported suggesting that bone formation ceases along portions of the periosteum during spaceflight. Visualized by microradiography, the arrest lines are shown to be less mineralized than the surrounding bone matrix. When viewed by scanning electron microscopy, it is seen that bone fractures more readily at the site of an arrest line. These observations are seen as suggesting that arrest lines are a zone of weakness and that their formation may result in decreased bone strength in spite of normalization of bone formation after flight. The occurrence, location, and morphology of arrest lines are seen as suggesting that they are a visible result of the phenomenon of arrested bone formation.

Formation of soap bubbles by gas jet

NASA Astrophysics Data System (ADS)

Zhou, Maolei; Li, Min; Chen, Zhiyuan; Han, Jifeng; Liu, Dong

2017-12-01

Soap bubbles can be easily generated by various methods, while their formation process is complicated and still worth studying. A model about the bubble formation process was proposed in the study by Salkin et al. [Phys. Rev. Lett. 116, 077801 (2016)] recently, and it was reported that the bubbles were formed when the gas blowing velocity was above one threshold. However, after a detailed study of these experiments, we found that the bubbles could be generated in two velocity ranges which corresponded to the laminar and turbulent gas jet, respectively, and the predicted threshold was only effective for turbulent gas flow. The study revealed that the bubble formation was greatly influenced by the aerodynamics of the gas jet blowing to the film, and these results will help to further understand the formation mechanism of the soap bubble as well as the interaction between the gas jet and the thin liquid film.

Mars brine formation experiment

NASA Technical Reports Server (NTRS)

Moore, Jeffrey M.; Bullock, Mark A.; Stoker, Carol R.

1992-01-01

Evaporites, particularly carbonates, nitrates, and sulfates, may be major sinks of volatiles scavenged from the martian atmosphere. Mars is thought to have once had a denser, warmer atmosphere that permitted the presence of liquid surface water. The conversion of atmospheric CO2 into carbonate is hypothesized to have degraded the martian climate to its present state of a generally subfreezing, desiccated desert. The rate for such a conversion under martian conditions is poorly known, so the time scale of climate degradation by this process cannot be easily evaluated. If some models are correct, carbonate formation may have been fast at geological time scales. The experiments of Booth and Kieffer also imply fast (10(exp 6) - 10(exp 7) yr) removal of the missing CO2 inventory, estimated to be 1 - 5 bar, by means of carbonate formation. The timing of formation of many of the fluvial features observed on Mars is, in large part, dependent on when and how fast the atmosphere changed. A knowledge of the rate at which carbonates and nitrates formed is also essential for assessing the probability that life, or its chemical precursors, could have developed on Mars. No previous experiments have quantitatively evaluated the rate of solution for a suite of mobile anions and cations from unaltered minerals and atmospheric gases into liquid water under Mars-like conditions. Such experiments are the focus of this task.

The role of chloramine species in NDMA formation.

PubMed

Selbes, Meric; Beita-Sandí, Wilson; Kim, Daekyun; Karanfil, Tanju

2018-09-01

N-nitrosodimethylamine (NDMA), a probable human carcinogen disinfection by-product, has been detected in chloraminated drinking water systems. Understanding its formation over time is important to control NDMA levels in distribution systems. The main objectives of this study were to investigate the role of chloramine species (i.e., monochloramine and dichloramine); and the factors such as pH, sulfate, and natural organic matter (NOM) influencing the formation of NDMA. Five NDMA precursors (i.e., dimethylamine (DMA), trimethylamine (TMA), N,N-dimethylisopropylamine (DMiPA), N,N-dimethylbenzylamine (DMBzA), and ranitidine (RNTD)) were carefully selected based on their chemical structures and exposed to varying ratios of monochloramine and dichloramine. All amine precursors reacted relatively fast to form NDMA and reached their maximum NDMA yields within 24 h in the presence of excess levels of chloramines (both mono- and dichloramine) or excess levels of dichloramine conditions (with limited monochloramine). When the formation of dichloramine was suppressed (i.e., only monochloramine existed in the system) over the 5 day contact time, NDMA formation from DMA, TMA, and DMiPA was drastically reduced (∼0%). Under monochloramine abundant conditions, however, DMBzA and RNTD showed 40% and 90% NDMA conversions at the end of 5 day contact time, respectively, with slow formation rates, indicating that while these amine precursors react preferentially with dichloramine to form NDMA, they can also react with monochloramine in the absence of dichloramine. NOM and pH influenced dichloramine levels that affected NDMA yields. NOM had an adverse effect on NDMA formation as it created a competition with NDMA precursors for dichloramine. Sulfate did not increase the NDMA formation from the two selected NDMA precursors. pH played a key role as it influenced both chloramine speciation and protonation state of amine precursors and the highest NDMA formation was observed at the p

Forced migration, adolescence, and identity formation.

PubMed

Anagnostopoulos, Dimitris C; Vlassopoulos, Maria; Lazaratou, Helen

2006-09-01

Adolescence is a complex biopsychosocial phenomenon. All the inner-subjective changes in adolescents take place within the context of a specific social environment, which offers the necessary ideological setting that adolescents must confront in the course of their identity formation. Forced migration creates conditions under which the adolescent Ego may be traumatized more easily, resulting in the development of defensive mechanisms, which may interfere with the natural process of identity formation. The aim of this paper is to investigate how a traumatic situation such as forced migration may affect the mechanisms of identity formation in adolescence. For this purpose, clinical material, consisting of two cases of psychoanalytical psychotherapy of adolescents who were forced to immigrate to Greece, is presented and discussed in a psychoanalytical theoretical framework, along with the historical-sociological background.

String cavitation formation inside fuel injectors

NASA Astrophysics Data System (ADS)

Reid, B. A.; Gavaises, M.; Mitroglou, N.; Hargrave, G. K.; Garner, C. P.; McDavid, R. M.

2015-12-01

The formation of vortex or ‘string’ cavitation has been visualised at pressures up to 2000 bar in an automotive-sized optical diesel fuel injector nozzle. The multi-hole nozzle geometry studied allowed observation of the hole-to-hole vortex interaction and, in particular, that of a bridging vortex in the sac region between the holes. Above a threshold Reynolds number, their formation and appearance during a 2 ms injection event was repeatable and independent of upstream pressure and cavitation number. In addition, two different hole layouts and threedimensional flow simulations have been employed to describe how, the relative positions of adjacent holes influenced the formation and hole-to-hole interaction of the observed string cavitation vortices, with good agreement between the experimental and simulation results being achieved.

What is meant by Format Version? Product Version? Collection?

Atmospheric Science Data Center

2017-10-12

The format Version is used to distinguish between software deliveries to ASDC that result in a product format change. The format version is given in the MISR data file name using the designator _Fnn_ where nn is the version number. ...

Smectite formation in the presence of sulfuric acid: Implications for acidic smectite formation on early Mars

NASA Astrophysics Data System (ADS)

Peretyazhko, T. S.; Niles, P. B.; Sutter, B.; Morris, R. V.; Agresti, D. G.; Le, L.; Ming, D. W.

2018-01-01

The excess of orbital detection of smectite deposits compared to carbonate deposits on the martian surface presents an enigma because smectite and carbonate formations are both favored alteration products of basalt under neutral to alkaline conditions. We propose that Mars experienced acidic events caused by sulfuric acid (H2SO4) that permitted phyllosilicate, but inhibited carbonate, formation. To experimentally verify this hypothesis, we report the first synthesis of smectite from Mars-analogue glass-rich basalt simulant (66 wt% glass, 32 wt% olivine, 2 wt% chromite) in the presence of H2SO4 under hydrothermal conditions (∼200 °C). Smectites were analyzed by X-ray diffraction, Mössbauer spectroscopy, visible and near-infrared reflectance spectroscopy and electron microprobe to characterize mineralogy and chemical composition. Solution chemistry was determined by Inductively Coupled Plasma Mass Spectrometry. Basalt simulant suspensions in 11-42 mM H2SO4 were acidic with pH ≤ 2 at the beginning of incubation and varied from acidic (pH 1.8) to mildly alkaline (pH 8.4) at the end of incubation. Alteration of glass phase during reaction of the basalt simulant with H2SO4 led to formation of the dioctahedral smectite at final pH ∼3 and trioctahedral smectite saponite at final pH ∼4 and higher. Anhydrite and hematite formed in the final pH range from 1.8 to 8.4 while natroalunite was detected at pH 1.8. Hematite was precipitated as a result of oxidative dissolution of olivine present in Adirondack basalt simulant. Formation of secondary phases, including smectite, resulted in release of variable amounts of Si, Mg, Na and Ca while solubilization of Al and Fe was low. Comparison of mineralogical and solution chemistry data indicated that the type of smectite (i.e., dioctahedral vs trioctahedral) was likely controlled by Mg leaching from altering basalt and substantial Mg loss created favorable conditions for formation of dioctahedral smectite. We present a model

Motivating student learning using a formative assessment journey

PubMed Central

Evans, Darrell J R; Zeun, Paul; Stanier, Robert A

2014-01-01

Providing formative assessment opportunities has been recognised as a significant benefit to student learning. The outcome of any formative assessment should be one that ultimately helps improve student learning through familiarising students with the levels of learning required, informing them about gaps in their learning and providing feedback to guide the direction of learning. This article provides an example of how formative assessments can be developed into a formative assessment journey where a number of different assessments can be offered to students during the course of a module of teaching, thus utilising a spaced-education approach. As well as incorporating the specific drivers of formative assessment, we demonstrate how approaches deemed to be stimulating, interactive and entertaining with the aim of maximising enthusiasm and engagement can be incorporated. We provide an example of a mixed approach to evaluating elements of the assessment journey that focuses student reaction, appraisal of qualitative and quantitative feedback from student questionnaires, focus group analysis and teacher observations. Whilst it is not possible to determine a quantifiable effect of the assessment journey on student learning, usage data and student feedback shows that formative assessment can achieve high engagement and positive response to different assessments. Those assessments incorporating an active learning element and a quiz-based approach appear to be particularly popular. A spaced-education format encourages a building block approach to learning that is continuous in nature rather than focussed on an intense period of study prior to summative examinations. PMID:24111930

[Accidents with biological material at West Paraná University Hospital].

PubMed

Murofuse, Neide Tiemi; Marziale, Maria Helena Palucci; Gemelli, Lorena Moraes Goetem

2005-08-01

It is a descriptive and retrospective study with the purpose of investigating labor accidents with biological material involving workers and trainees occurred in 2003 and 2004 in a University Hospital of Parana. For data collection, the electronic form of the Net of Occupational Accidents Prevention - REPAT has been utilized. Out of the 586 hospital workers, there was a register of 20 (3,4%) injured workers in 2003 and 23 (3,8%) in 2004, representing an increase of 15% in the notifications from one year to the other.

Achievement Goal Orientations and Identity Formation Styles

ERIC Educational Resources Information Center

Kaplan, Avi; Flum, Hanoch

2010-01-01

The present article points to shared underlying theoretical assumptions and central processes of a prominent academic motivation perspective--achievement goal theory--and recent process perspectives in the identity formation literature, and more specifically, identity formation styles. The review highlights the shared definition of achievement…

Harnessing Collaborative Annotations on Online Formative Assessments

ERIC Educational Resources Information Center

Lin, Jian-Wei; Lai, Yuan-Cheng

2013-01-01

This paper harnesses collaborative annotations by students as learning feedback on online formative assessments to improve the learning achievements of students. Through the developed Web platform, students can conduct formative assessments, collaboratively annotate, and review historical records in a convenient way, while teachers can generate…

Bone formation: roles of genistein and daidzein

USDA-ARS?s Scientific Manuscript database

Bone remodeling consists of a balance between bone formation by osteoblasts and bone resorption by osteoclasts. Osteoporosis is the result of increased bone resorption and decreased bone formation causing a decreased bone mass density, loss of bone microarchitecture, and an increased risk of fractu...

Formate and its role in hydrogen production in Escherichia coli.

PubMed

Sawers, R G

2005-02-01

The production of dihydrogen by Escherichia coli and other members of the Enterobacteriaceae is one of the classic features of mixed-acid fermentation. Synthesis of the multicomponent, membrane-associated FHL (formate hydrogenlyase) enzyme complex, which disproportionates formate into CO(2) and H(2), has an absolute requirement for formate. Formate, therefore, represents a signature molecule in the fermenting E. coli cell and factors that determine formate metabolism control FHL synthesis and consequently dihydrogen evolution.

The role of fanatics in consensus formation

NASA Astrophysics Data System (ADS)

Gündüç, Semra

2015-08-01

A model of opinion dynamics with two types of agents as social actors are presented, using the Ising thermodynamic model as the dynamics template. The agents are considered as opportunists which live at sites and interact with the neighbors, or fanatics/missionaries which move from site to site randomly in persuasion of converting agents of opposite opinion with the help of opportunists. Here, the moving agents act as an external influence on the opportunists to convert them to the opposite opinion. It is shown by numerical simulations that such dynamics of opinion formation may explain some details of consensus formation even when one of the opinions are held by a minority. Regardless the distribution of the opinion, different size societies exhibit different opinion formation behavior and time scales. In order to understand general behavior, the scaling relations obtained by comparing opinion formation processes observed in societies with varying population and number of randomly moving agents are studied. For the proposed model two types of scaling relations are observed. In fixed size societies, increasing the number of randomly moving agents give a scaling relation for the time scale of the opinion formation process. The second type of scaling relation is due to the size dependent information propagation in finite but large systems, namely finite-size scaling.

Directory interchange format manual, version 4.0

NASA Technical Reports Server (NTRS)

1991-01-01

The Directory Interchange Format (DIF) is a data structure used to exchange directory-level information about data sets among information systems. In general the format consists of a number of fields that describe the attributes of a directory entry and text blocks that contain a descriptive summary of and references for the directory entry. All fields and the summary are preceded by labels identifying their contents. All values are ASCII character strings. The structure is intended to be flexible, allowing for future changes in the contents of directory entries. The manual is structured as follows: section 1 is a general description of what constitutes a directory entry; section 2 describes the content of the individual fields within the data structure, together with some examples. Also included in the six appendices is a description of the syntax used within the examples; samples of the directory interchange format applied to different data sets; the allowable discipline keywords; a current list of valid location keywords; a list of allowable parameter keywords; a list of acronyns and a glossary of terms used; and a description of the Standard Formatted Data Unit header, which may be added to the front of a DIF file to identify the file as a registered standard format.

Adolescent Violent Victimization and Precocious Union Formation*

PubMed Central

C. Kuhl, Danielle; Warner, David F.; Wilczak, Andrew

2013-01-01

This article bridges scholarship in criminology and family sociology by extending arguments about “precocious exits” from adolescence to consider early union formation as a salient outcome of violent victimization for youths. Research indicates that early union formation is associated with several negative outcomes; yet the absence of attention to union formation as a consequence of violent victimization is noteworthy. We address this gap by drawing on life course theory and data from the National Longitudinal Study of Adolescent Health (Add Health) to examine the effect of violent victimization (“street” violence) on the timing of first co-residential union formation—differentiating between marriage and cohabitation—in young adulthood. Estimates from Cox proportional hazard models show that adolescent victims of street violence experience higher rates of first union formation, especially marriage, early in the transition to adulthood; however, this effect declines with age, as such unions become more normative. Importantly, the effect of violent victimization on first union timing is robust to controls for nonviolent delinquency, substance abuse, and violent perpetration. We conclude by discussing directions for future research on the association between violent victimization and coresidential unions with an eye toward the implications of such early union formation for desistance. PMID:24431471

Self-organization principles of intracellular pattern formation.

PubMed

Halatek, J; Brauns, F; Frey, E

2018-05-26

Dynamic patterning of specific proteins is essential for the spatio-temporal regulation of many important intracellular processes in prokaryotes, eukaryotes and multicellular organisms. The emergence of patterns generated by interactions of diffusing proteins is a paradigmatic example for self-organization. In this article, we review quantitative models for intracellular Min protein patterns in Escherichia coli , Cdc42 polarization in Saccharomyces cerevisiae and the bipolar PAR protein patterns found in Caenorhabditis elegans By analysing the molecular processes driving these systems we derive a theoretical perspective on general principles underlying self-organized pattern formation. We argue that intracellular pattern formation is not captured by concepts such as 'activators', 'inhibitors' or 'substrate depletion'. Instead, intracellular pattern formation is based on the redistribution of proteins by cytosolic diffusion, and the cycling of proteins between distinct conformational states. Therefore, mass-conserving reaction-diffusion equations provide the most appropriate framework to study intracellular pattern formation. We conclude that directed transport, e.g. cytosolic diffusion along an actively maintained cytosolic gradient, is the key process underlying pattern formation. Thus the basic principle of self-organization is the establishment and maintenance of directed transport by intracellular protein dynamics.This article is part of the theme issue 'Self-organization in cell biology'. © 2018 The Authors.

Anaerobic Formate and Hydrogen Metabolism.

PubMed

Sawers, R Gary; Blokesch, Melanie; Böck, August

2004-12-01

During fermentative growth, Escherichia coli degrades carbohydrates via the glycolytic route into two pyruvate molecules. Pyruvate can be reduced to lactate or nonoxidatively cleaved by pyruvate formate lyase into acetyl-coenzyme A (acetyl-CoA) and formate. Acetyl-CoA can be utilized for energy conservation in the phosphotransacetylase (PTA) and acetate kinase (ACK) reaction sequence or can serve as an acceptor for reducing equivalents gathered during pyruvate formation, through the action of alcohol dehydrogenase (AdhE). Formic acid is strongly acidic and has a redox potential of -420 mV under standard conditions and therefore can be classified as a high-energy compound. Its disproportionation into CO2 and molecular hydrogen (Em,7 -420 mV) via the formate hydrogenlyase (FHL) system is therefore of high selective value. The FHL reaction involves the participation of at least seven proteins, most of which are metalloenzymes, with requirements for iron, molybdenum, nickel, or selenium. Complex auxiliary systems incorporate these metals. Reutilization of the hydrogen evolved required the evolution of H2 oxidation systems, which couple the oxidation process to an appropriate energy-conserving terminal reductase. E. coli has two hydrogen-oxidizing enzyme systems. Finally, fermentation is the "last resort" of energy metabolism, since it gives the minimal energy yield when compared with respiratory processes. Consequently, fermentation is used only when external electron acceptors are absent. This has necessitated the establishment of regulatory cascades, which ensure that the metabolic capability is appropriately adjusted to the physiological condition. Here we review the genetics, biochemistry, and regulation of hydrogen metabolism and its hydrogenase maturation system.

Controlling and assessing pressure conditions during treatment of tar sands formations

DOEpatents

Zhang, Etuan; Beer, Gary Lee

2015-11-10

A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the tar sands formation from a plurality of heaters located in the formation. Heat is allowed to transfer from the heaters to at least a portion of the formation. A pressure in the portion of the formation is controlled such that the pressure remains below a fracture pressure of the formation overburden while allowing the portion of the formation to heat to a selected average temperature of at least about 280.degree. C. and at most about 300.degree. C. The pressure in the portion of the formation is reduced to a selected pressure after the portion of the formation reaches the selected average temperature.

Prediction of Phase Formation in Nanoscale Sn-Ag-Cu Solder Alloy

NASA Astrophysics Data System (ADS)

Wu, Min; Lv, Bailin

2016-01-01

In a dynamic nonequilibrium process, the effective heat of formation allows the heat of formation to be calculated as a function of concentrations of the reacting atoms. In this work, we used the effective heat of formation rule to predict the formation and size of compound phases in a nanoscale Sn-Ag-Cu lead-free solder. We calculated the formation enthalpy and effective formation enthalpy of compounds in the Sn-Ag, Sn-Cu, and Ag-Cu systems by using the Miedema model and effective heat of formation. Our results show that, considering the surface effect of the nanoparticle, the effective heat of formation rule successfully predicts the phase formation and sizes of Ag3Sn and Cu6Sn5 compounds, which agrees well with experimental data.

Relative Attitude Determination of Earth Orbiting Formations Using GPS Receivers

NASA Technical Reports Server (NTRS)

Lightsey, E. Glenn

2004-01-01

Satellite formation missions require the precise determination of both the position and attitude of multiple vehicles to achieve the desired objectives. In order to support the mission requirements for these applications, it is necessary to develop techniques for representing and controlling the attitude of formations of vehicles. A generalized method for representing the attitude of a formation of vehicles has been developed. The representation may be applied to both absolute and relative formation attitude control problems. The technique is able to accommodate formations of arbitrarily large number of vehicles. To demonstrate the formation attitude problem, the method is applied to the attitude determination of a simple leader-follower along-track orbit formation. A multiplicative extended Kalman filter is employed to estimate vehicle attitude. In a simulation study using GPS receivers as the attitude sensors, the relative attitude between vehicles in the formation is determined 3 times more accurately than the absolute attitude.

Cogeneration systems and processes for treating hydrocarbon containing formations

DOEpatents

Vinegar, Harold J [Bellaire, TX; Fowler, Thomas David [Houston, TX; Karanikas, John Michael [Houston, TX

2009-12-29

A system for treating a hydrocarbon containing formation includes a steam and electricity cogeneration facility. At least one injection well is located in a first portion of the formation. The injection well provides steam from the steam and electricity cogeneration facility to the first portion of the formation. At least one production well is located in the first portion of the formation. The production well in the first portion produces first hydrocarbons. At least one electrical heater is located in a second portion of the formation. At least one of the electrical heaters is powered by electricity from the steam and electricity cogeneration facility. At least one production well is located in the second portion of the formation. The production well in the second portion produces second hydrocarbons. The steam and electricity cogeneration facility uses the first hydrocarbons and/or the second hydrocarbons to generate electricity.

Planet Formation - Overview

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

2005-01-01

Modern theories of star and planet formation are based upon observations of planets and smaller bodies within our own Solar System, exoplanets &round normal stars and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. These models predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path.

Formation of bacterial nanocells

NASA Astrophysics Data System (ADS)

Vainshtein, Mikhail; Kudryashova, Ekaterina; Suzina, Natalia; Ariskina, Elena; Voronkov, Vadim

1998-07-01

Existence of nanobacteria received increasing attention both in environmental microbiology/geomicro-biology and in medical microbiology. In order to study a production of nanoforms by typical bacterial cells. Effects of different physical factors were investigated. Treatment of bacterial cultures with microwave radiation, or culturing in field of electric current resulted in formation a few types of nanocells. The number and type of nanoforms were determined with type and dose of the treatment. The produced nanoforms were: i) globules, ii) clusters of the globules--probably produced by liaison, iii) nanocells coated with membrane. The viability of the globules is an object opened for doubts. The nanocells discovered multiplication and growth on solidified nutrient media. The authors suggest that formation of nanocells is a common response of bacteria to stress-actions produced by different agents.

Formation of Planetary Systems

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.; DeVincenzi, Donald (Technical Monitor)

1999-01-01

An overview of current theories of star and planet formation is presented. These models are based upon observations of the Solar System and of young stars and their environments. They predict that rocky planets should form around most single stars, although it is possible that in some cases such planets are lost to orbital decay within the protoplanetary disk. The frequency of formation of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth like terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates.

Format guidelines to make them vivid, intuitive, and visual: use simple formatting rules to optimize usability and accessibility of clinical practice guidelines.

PubMed

Versloot, Judith; Grudniewicz, Agnes; Chatterjee, Ananda; Hayden, Leigh; Kastner, Monika; Bhattacharyya, Onil

2015-06-01

We present simple formatting rules derived from an extensive literature review that can improve the format of clinical practice guidelines (CPGs), and potentially increase the likelihood of being used. We recently conducted a review of the literature from medicine, psychology, design, and human factors engineering on characteristics of guidelines that are associated with their use in practice, covering both the creation and communication of content. The formatting rules described in this article are derived from that review. The formatting rules are grouped into three categories that can be easily applied to CPGs: first, Vivid: make it stand out; second, Intuitive: match it to the audience's expectations, and third, Visual: use alternatives to text. We highlight rules supported by our broad literature review and provide specific 'how to' recommendations for individuals and groups developing evidence-based materials for clinicians. The way text documents are formatted influences their accessibility and usability. Optimizing the formatting of CPGs is a relatively inexpensive intervention and can be used to facilitate the dissemination of evidence in healthcare. Applying simple formatting principles to make documents more vivid, intuitive, and visual is a practical approach that has the potential to influence the usability of guidelines and to influence the extent to which guidelines are read, remembered, and used in practice.

The Impact of Test Dimensionality, Common-Item Set Format, and Scale Linking Methods on Mixed-Format Test Equating

ERIC Educational Resources Information Center

Öztürk-Gübes, Nese; Kelecioglu, Hülya

2016-01-01

The purpose of this study was to examine the impact of dimensionality, common-item set format, and different scale linking methods on preserving equity property with mixed-format test equating. Item response theory (IRT) true-score equating (TSE) and IRT observed-score equating (OSE) methods were used under common-item nonequivalent groups design.…

Formative and Summative Evaluation: Related Issues in Performance Measurement.

ERIC Educational Resources Information Center

Wholey, Joseph S.

1996-01-01

Performance measurement can serve both formative and summative evaluation functions. Formative evaluation is typically more useful for government purposes whereas performance measurement is more useful than one-shot evaluations of either formative or summative nature. Evaluators should study performance measurement through case studies and…

Report formatting in laboratory medicine - a call for harmony.

PubMed

Jones, Graham R D; Legg, Michael

2018-04-19

The results of medical laboratory testing are only useful if they lead to appropriate actions by medical practitioners and/or patients. An underappreciated component of the medical testing process is the transfer of the information from the laboratory report into the reader's brain. The format of laboratory reports can be determined by the testing laboratory, which may issue a formatted report, or by electronic systems receiving information from laboratories and controlling the report format. As doctors can receive information from many laboratories, interpreting information from reports in a safe and rapid manner is facilitated by having similar report layouts and formats. Using Australia as an example, there is a wide variation in report formats in spite of a body of work to define standards for reporting. In addition to standardising of report formats, consideration needs to be given to optimisation of report formatting to facilitate rapid and unambiguous reading of the report and also interpretation of the data. Innovative report formats have been developed by some laboratories; however, wide adoption has not followed. The need to balance uniformity of reporting with appropriate innovation is a challenge for safe reporting of laboratory results. This paper discusses the current status and opportunity for improvement in safety and efficiency of the reading of laboratory reports, using current practise and developments in Australia as examples.

Rethinking pattern formation in reaction-diffusion systems

NASA Astrophysics Data System (ADS)

Halatek, J.; Frey, E.

2018-05-01

The present theoretical framework for the analysis of pattern formation in complex systems is mostly limited to the vicinity of fixed (global) equilibria. Here we present a new theoretical approach to characterize dynamical states arbitrarily far from (global) equilibrium. We show that reaction-diffusion systems that are driven by locally mass-conserving interactions can be understood in terms of local equilibria of diffusively coupled compartments. Diffusive coupling generically induces lateral redistribution of the globally conserved quantities, and the variable local amounts of these quantities determine the local equilibria in each compartment. We find that, even far from global equilibrium, the system is well characterized by its moving local equilibria. We apply this framework to in vitro Min protein pattern formation, a paradigmatic model for biological pattern formation. Within our framework we can predict and explain transitions between chemical turbulence and order arbitrarily far from global equilibrium. Our results reveal conceptually new principles of self-organized pattern formation that may well govern diverse dynamical systems.

Pebble pile-up and planetesimal formation at the snow line

NASA Astrophysics Data System (ADS)

Drazkowska, J.

2017-09-01

The planetesimal formation stage represents a major gap in our understanding of planet formation process. Because of this, the late-stage planet accretion models typically make arbitrary assumptions about planetesimals and pebbles distribution, while the state-of-the-art dust evolution models predict no or little planetesimal formation. With this contribution, I present a step toward bridging the gap between the early and late stages of planet formation by models that connect dust coagulation and planetesimal formation. With the aid of evaporation, outward diffusion, and re-condensation of water vapor, pile-up of large pebbles is formed outside of the snow line that facilitates planetesimal formation by streaming instability.

Research on formation of microsatellite communication with genetic algorithm.

PubMed

Wu, Guoqiang; Bai, Yuguang; Sun, Zhaowei

2013-01-01

For the formation of three microsatellites which fly in the same orbit and perform three-dimensional solid mapping for terra, this paper proposes an optimizing design method of space circular formation order based on improved generic algorithm and provides an intersatellite direct spread spectrum communication system. The calculating equation of LEO formation flying satellite intersatellite links is guided by the special requirements of formation-flying microsatellite intersatellite links, and the transmitter power is also confirmed throughout the simulation. The method of space circular formation order optimizing design based on improved generic algorithm is given, and it can keep formation order steady for a long time under various absorb impetus. The intersatellite direct spread spectrum communication system is also provided. It can be found that, when the distance is 1 km and the data rate is 1 Mbps, the input wave matches preferably with the output wave. And LDPC code can improve the communication performance. The correct capability of (512, 256) LDPC code is better than (2, 1, 7) convolution code, distinctively. The design system can satisfy the communication requirements of microsatellites. So, the presented method provides a significant theory foundation for formation-flying and intersatellite communication.

Planetesimal formation during protoplanetary disk buildup

NASA Astrophysics Data System (ADS)

Drążkowska, J.; Dullemond, C. P.

2018-06-01

Context. Models of dust coagulation and subsequent planetesimal formation are usually computed on the backdrop of an already fully formed protoplanetary disk model. At the same time, observational studies suggest that planetesimal formation should start early, possibly even before the protoplanetary disk is fully formed. Aims: In this paper we investigate under which conditions planetesimals already form during the disk buildup stage, in which gas and dust fall onto the disk from its parent molecular cloud. Methods: We couple our earlier planetesimal formation model at the water snow line to a simple model of disk formation and evolution. Results: We find that under most conditions planetesimals only form after the buildup stage, when the disk becomes less massive and less hot. However, there are parameters for which planetesimals already form during the disk buildup. This occurs when the viscosity driving the disk evolution is intermediate (αv 10-3-10-2) while the turbulent mixing of the dust is reduced compared to that (αt ≲ 10-4), and with the assumption that the water vapor is vertically well-mixed with the gas. Such a αt ≪ αv scenario could be expected for layered accretion, where the gas flow is mostly driven by the active surface layers, while the midplane layers, where most of the dust resides, are quiescent. Conclusions: In the standard picture where protoplanetary disk accretion is driven by global turbulence, we find that no planetesimals form during the disk buildup stage. Planetesimal formation during the buildup stage is only possible in scenarios in which pebbles reside in a quiescent midplane while the gas and water vapor are diffused at a higher rate.

Protocol for Communication Networking for Formation Flying

NASA Technical Reports Server (NTRS)

Jennings, Esther; Okino, Clayton; Gao, Jay; Clare, Loren

2009-01-01

An application-layer protocol and a network architecture have been proposed for data communications among multiple autonomous spacecraft that are required to fly in a precise formation in order to perform scientific observations. The protocol could also be applied to other autonomous vehicles operating in formation, including robotic aircraft, robotic land vehicles, and robotic underwater vehicles. A group of spacecraft or other vehicles to which the protocol applies could be characterized as a precision-formation- flying (PFF) network, and each vehicle could be characterized as a node in the PFF network. In order to support precise formation flying, it would be necessary to establish a corresponding communication network, through which the vehicles could exchange position and orientation data and formation-control commands. The communication network must enable communication during early phases of a mission, when little positional knowledge is available. Particularly during early mission phases, the distances among vehicles may be so large that communication could be achieved only by relaying across multiple links. The large distances and need for omnidirectional coverage would limit communication links to operation at low bandwidth during these mission phases. Once the vehicles were in formation and distances were shorter, the communication network would be required to provide high-bandwidth, low-jitter service to support tight formation-control loops. The proposed protocol and architecture, intended to satisfy the aforementioned and other requirements, are based on a standard layered-reference-model concept. The proposed application protocol would be used in conjunction with conventional network, data-link, and physical-layer protocols. The proposed protocol includes the ubiquitous Institute of Electrical and Electronics Engineers (IEEE) 802.11 medium access control (MAC) protocol to be used in the datalink layer. In addition to its widespread and proven use in

Simultaneous junction formation

NASA Technical Reports Server (NTRS)

Campbell, R. B.

1984-01-01

High-risk, high-payoff improvements to a baseline process sequence of simultaneous junction formation of silicon solar cells are discussed. The feasibility of simultaneously forming front and back junctions of solar cells using liquid dopants on dendritic web silicon was studied. Simultaneous diffusion was compared to sequential diffusion. A belt furnace for the diffusion process was tested.

Star Formation and the Hall Effect

NASA Astrophysics Data System (ADS)

Braiding, Catherine

2011-10-01

Magnetic fields play an important role in star formation by regulating the removal of angular momentum from collapsing molecular cloud cores. Hall diffusion is known to be important to the magnetic field behaviour at many of the intermediate densities and field strengths encountered during the gravitational collapse of molecular cloud cores into protostars, and yet its role in the star formation process is not well-studied. This thesis describes a semianalytic self-similar model of the collapse of rotating isothermal molecular cloud cores with both Hall and ambipolar diffusion, presenting similarity solutions that demonstrate that the Hall effect has a profound influence on the dynamics of collapse. ... Hall diffusion also determines the strength of the magnetic diffusion and centrifugal shocks that bound the pseudo and rotationally-supported discs, and can introduce subshocks that further slow accretion onto the protostar. In cores that are not initially rotating Hall diffusion can even induce rotation, which could give rise to disc formation and resolve the magnetic braking catastrophe. The Hall effect clearly influences the dynamics of gravitational collapse and its role in controlling the magnetic braking and radial diffusion of the field would be worth exploring in future numerical simulations of star formation.

Star formation: Cosmic feast

NASA Astrophysics Data System (ADS)

Scaringi, Simone

2016-11-01

Low-mass stars form through a process known as disk accretion, eating up material that orbits in a disk around them. It turns out that the same mechanism also describes the formation of more massive stars.

Star formation: Cosmic feast

NASA Astrophysics Data System (ADS)

Scaringi, Simone

2017-03-01

Low-mass stars form through a process known as disk accretion, eating up material that orbits in a disk around them. It turns out that the same mechanism also describes the formation of more massive stars.

30 CFR 777.11 - Format and contents.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Format and contents. 777.11 Section 777.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR SURFACE... GENERAL CONTENT REQUIREMENTS FOR PERMIT APPLICATIONS § 777.11 Format and contents. (a) An application...

30 CFR 777.11 - Format and contents.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Format and contents. 777.11 Section 777.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR SURFACE... GENERAL CONTENT REQUIREMENTS FOR PERMIT APPLICATIONS § 777.11 Format and contents. (a) An application...

32 CFR 865.126 - Sample report format.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 6 2011-07-01 2011-07-01 false Sample report format. 865.126 Section 865.126 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ORGANIZATION AND MISSION-GENERAL PERSONNEL REVIEW BOARDS Air Force Discharge Review Board § 865.126 Sample report format. Summary...

32 CFR 865.126 - Sample report format.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 6 2013-07-01 2013-07-01 false Sample report format. 865.126 Section 865.126 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ORGANIZATION AND MISSION-GENERAL PERSONNEL REVIEW BOARDS Air Force Discharge Review Board § 865.126 Sample report format. Summary...

[Current problems in price formation in public health].

PubMed

Poliakov, I V; Uvarov, S A; Seleznev, V D; Zelenskaia, T M

1996-01-01

Adequate policy of price formation is one condition for effective development of public health under conditions of market economy. The authors present the fundamentals of price formation in public health under conditions of state financing, insurance, and self-support. Price formation should promote the activities of public health institutions, aimed at improving the quality of medical aid to the population and at the creation of conditions for the welfare of medical workers.

Common Data Format: New XML and Conversion Tools

NASA Astrophysics Data System (ADS)

Han, D. B.; Liu, M. H.; McGuire, R. E.

2002-12-01

Common Data Format (CDF) is a self-describing platform-independent data format for storing, accessing, and manipulating scalar and multidimensional scientific data sets. Significant benefit has accrued to specific science communities from their use of standard formats within those communities. Examples include the International Solar Terrestrial Physics (ISTP) community in using CDF for traditional space physics data (fields, particles and plasma, waves, and images), the worldwide astronomical community in using FITS (Flexible Image Transport System) for solar data (primarily spectral images), the NASA Planetary community in using Planetary Data System (PDS) Labels, and the earth science community in using Hierarchical Data Format (HDF). Scientific progress in solar-terrestrial physics continues to be impeded by the multiplicity of available standards for data formats and dearth of general data format translators. As a result, scientists today spend a significant amount of time translating data into the format they are familiar with for their research. To minimize this unnecessary data translation time and to allow more research time, the CDF office located at GSFC National Space Science Data Center (NSSDC) has developed HDF-to-CDF and FITS-to-CDF translators, and employed the eXtensible Markup Language (XML) technology to facilitate and promote data interoperability within the space science community. We will present the current status of the CDF work including the conversion tools that have been recently developed, conversion tools that are planned in the near future, share some of the XML experiences, and use the discussion to gain community feedback to our planned future work.

Evaluation of Electronic Formats of the NASA Task Load Index

NASA Technical Reports Server (NTRS)

Trujillo, Anna C.

2011-01-01

Paper questionnaires are being replaced by electronic questionnaires. The primary objective of this research was to determine whether electronic formats of paper questionnaires change subjects ratings and, if so, how the ratings changed. Results indicated that there were no statistically significant differences in self-assessment of workload when using the electronic replica or the paper format of the NASA-TLX scale. Variations of the electronic formats were tested to enforce structure to the TLX scale. Respondents had more consistent ratings with these alternative formats of the NASA-TLX. Non-pilots, in general, had lower workload ratings than pilots. The time to input the rating was the fastest for the electronic facsimile and random title formats. Also subjects preferred the electronic formats and thought these formats were easier to use. Therefore, moving questionnaires from paper to electronic media could change respondents' answers.

Method of producing drive fluid in situ in tar sands formations

DOEpatents

Mudunuri, Ramesh Raju; Jaiswal, Namit; Vinegar, Harold J.; Karanikas, John Michael

2010-03-23

Methods of treating a tar sands formation are described herein. Methods for treating a tar sands may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. The heat may be allowed to transfer from the heaters to at least a portion of the formation such that a drive fluid is produced in situ in the formation. The drive fluid may move at least some mobilized, visbroken, and/or pyrolyzed hydrocarbons from a first portion of the formation to a second portion of the formation. At least some of the mobilized, visbroken, and/or pyrolyzed hydrocarbons may be produced from the formation.

Invariant Solar Sail Formations in Elliptical Sun-Synchronous Orbits

NASA Astrophysics Data System (ADS)

Parsay, Khashayar

Current and past missions that study the Earth's geomagnetic tail require multiple spacecraft to fly in formation about a highly eccentric Keplerian reference orbit that has its apogee inside a predefined science region of interest. Because the geomagnetic tail is directed along the Sun-Earth line and therefore rotates annually, inertially fixed Keplerian orbits are only aligned with the geomagnetic tail once per year. This limitation reduces the duration of the science phase to less than a few months annually. Solar sails are capable of creating non-Keplerian, Sun-synchronous orbits that rotate with the geomagnetic tail. A solar sail flying in a Sun-synchronous orbit will have a continuous presence in the geomagnetic tail throughout the entire year, which significantly improves the in situ observations of the magnetosphere. To achieve a Sun-synchronous orbit, a solar sail is required to maintain a Sun-pointing attitude, which leads to the artificial precession of the orbit apse line in a Sun-synchronous manner, leaving the orbit apogee inside the science region of interest throughout entire the year. To study the spatial and temporal variations of plasma in the highly dynamic environment of the magnetosphere, multiple spacecraft must fly in a formation. The objective for this dissertation is to investigate the feasibility of solar sail formation flying in the Earth-centered, Sun-synchronous orbit regime. The focus of this effort is to enable formation flying for a group of solar sails that maintain a nominally fixed Sun-pointing attitude during formation flight, solely for the purpose of precessing their orbit apse lines Sun-synchronously. A fixed-attitude solar sail formation is motivated by the difficulties in the simultaneous control of orbit and attitude in flying solar sails. First, the secular rates of the orbital elements resulting from the effects of solar radiation pressure (SRP) are determined using averaging theory for a Sun-pointing attitude sail

Using an ACTIVE teaching format versus a standard lecture format for increasing resident interaction and knowledge achievement during noon conference: a prospective, controlled study.

PubMed

Sawatsky, Adam P; Berlacher, Kathryn; Granieri, Rosanne

2014-07-01

The traditional lecture is used by many residency programs to fulfill the mandate for regular didactic sessions, despite limited evidence to demonstrate its effectiveness. Active teaching strategies have shown promise in improving medical knowledge but have been challenging to implement within the constraints of residency training. We developed and evaluated an innovative structured format for interactive teaching within the residency noon conference. We developed an ACTIVE teaching format structured around the following steps: assemble (A) into groups, convey (C) learning objectives, teach (T) background information, inquire (I) through cases and questions, verify (V) understanding, and explain (E) answer choices and educate on the learning points. We conducted a prospective, controlled study of the ACTIVE teaching format versus the standard lecture format, comparing resident satisfaction, immediate knowledge achievement and long-term knowledge retention. We qualitatively assessed participating faculty members' perspectives on the faculty development efforts and the feasibility of teaching using the ACTIVE format. Sixty-nine internal medicine residents participated in the study. Overall, there was an improvement in perceived engagement using the ACTIVE teaching format (4.78 vs. 3.80, P < 0.01), with no increase in stress or decrement in break time. There was an improvement in initial knowledge achievement with the ACTIVE teaching format (overall absolute score increase of 11%, P = 0.04) and a trend toward improvement in long-term knowledge retention. Faculty members felt adequately prepared to use the ACTIVE teaching format, and enjoyed teaching with the ACTIVE teaching format more than the standard lecture. A structured ACTIVE teaching format improved resident engagement and initial knowledge, and required minimal resources. The ACTIVE teaching format offers an exciting alternative to the standard lecture for resident noon conference and is easy to implement.

Using an ACTIVE teaching format versus a standard lecture format for increasing resident interaction and knowledge achievement during noon conference: a prospective, controlled study

PubMed Central

2014-01-01

Background The traditional lecture is used by many residency programs to fulfill the mandate for regular didactic sessions, despite limited evidence to demonstrate its effectiveness. Active teaching strategies have shown promise in improving medical knowledge but have been challenging to implement within the constraints of residency training. We developed and evaluated an innovative structured format for interactive teaching within the residency noon conference. Methods We developed an ACTIVE teaching format structured around the following steps: assemble (A) into groups, convey (C) learning objectives, teach (T) background information, inquire (I) through cases and questions, verify (V) understanding, and explain (E) answer choices and educate on the learning points. We conducted a prospective, controlled study of the ACTIVE teaching format versus the standard lecture format, comparing resident satisfaction, immediate knowledge achievement and long-term knowledge retention. We qualitatively assessed participating faculty members’ perspectives on the faculty development efforts and the feasibility of teaching using the ACTIVE format. Results Sixty-nine internal medicine residents participated in the study. Overall, there was an improvement in perceived engagement using the ACTIVE teaching format (4.78 vs. 3.80, P < 0.01), with no increase in stress or decrement in break time. There was an improvement in initial knowledge achievement with the ACTIVE teaching format (overall absolute score increase of 11%, P = 0.04) and a trend toward improvement in long-term knowledge retention. Faculty members felt adequately prepared to use the ACTIVE teaching format, and enjoyed teaching with the ACTIVE teaching format more than the standard lecture. Conclusions A structured ACTIVE teaching format improved resident engagement and initial knowledge, and required minimal resources. The ACTIVE teaching format offers an exciting alternative to the standard lecture for

The crazy hollow formation (Eocene) of central Utah

USGS Publications Warehouse

Weiss, M.P.; Warner, K.N.

2001-01-01

The Late Eocene Crazy Hollow Formation is a fluviatile and lacustrine unit that was deposited locally in the southwest arm of Lake Uinta during and after the last stages of the lake the deposited the Green River Formation. Most exposures of the Crazy Hollow are located in Sanpete and Sevier Counties. The unit is characterized by a large variety of rock types, rapid facies changes within fairly short distances, and different lithofacies in the several areas where outcrops of the remnants of the formation are concentrated. Mudstone is dominant, volumetrically, but siltstone, shale, sandstone, conglomerate and several varieties of limestone are also present. The fine-grained rocks are mostly highly colored, especially in shades of yellow, orange and red. Sand grains, pebbles and small cobbles of well-rounded black chert are widespread, and "salt-and-pepper sandstone" is the conspicuous characteristic of the Crazy Hollow. The salt-and-pepper sandstone consists of grains of black chert, white chert, quartz and minor feldspar. The limestone beds and lenses are paludal and lacustrine in origin; some are fossiliferous, and contain the same fauna found in the Green River Formation. With trivial exceptions, the Crazy Hollow Formation lies on the upper, limestone member of the Green River Formation, and the beds of the two units are always accordant in attitude. The nature of the contact differs locally: at some sites there is gradation from the Green River to the Crazy Hollow; at others, rocks typical of the two units intertongue; elsewhere there is a disconformity between the two. A variety of bedrock units overlie the Crazy Hollow at different sites. In the southeasternmost districts it is overlain by the late Eocene formation of Aurora; in western Sevier County it is overlain by the Miocene-Pliocene Sevier River Formation; in northernmost Sanpete County it is overlain by the Oligocene volcanics of the Moroni Formation. At many sites bordering Sanpete and Sevier Valleys

12 CFR 749.4 - Format for vital records preservation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Format for vital records preservation. 749.4... RECORDS PRESERVATION PROGRAM AND APPENDICES-RECORD RETENTION GUIDELINES; CATASTROPHIC ACT PREPAREDNESS GUIDELINES § 749.4 Format for vital records preservation. Preserved records may be in any format that can be...

21 CFR 601.14 - Regulatory submissions in electronic format.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Regulatory submissions in electronic format. 601... SERVICES (CONTINUED) BIOLOGICS LICENSING Biologics Licensing § 601.14 Regulatory submissions in electronic format. (a) General. Electronic format submissions must be in a form that FDA can process, review, and...

21 CFR 601.14 - Regulatory submissions in electronic format.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Regulatory submissions in electronic format. 601... SERVICES (CONTINUED) BIOLOGICS LICENSING Biologics Licensing § 601.14 Regulatory submissions in electronic format. (a) General. Electronic format submissions must be in a form that FDA can process, review, and...

21 CFR 601.14 - Regulatory submissions in electronic format.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Regulatory submissions in electronic format. 601... SERVICES (CONTINUED) BIOLOGICS LICENSING Biologics Licensing § 601.14 Regulatory submissions in electronic format. (a) General. Electronic format submissions must be in a form that FDA can process, review, and...

Star formation is boosted (and quenched) from the inside-out: radial star formation profiles from MaNGA

NASA Astrophysics Data System (ADS)

Ellison, Sara L.; Sánchez, Sebastian F.; Ibarra-Medel, Hector; Antonio, Braulio; Mendel, J. Trevor; Barrera-Ballesteros, Jorge

2018-02-01

The tight correlation between total galaxy stellar mass and star formation rate (SFR) has become known as the star-forming main sequence. Using ˜487 000 spaxels from galaxies observed as part of the Sloan Digital Sky Survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we confirm previous results that a correlation also exists between the surface densities of star formation (ΣSFR) and stellar mass (Σ⋆) on kpc scales, representing a `resolved' main sequence. Using a new metric (ΔΣSFR), which measures the relative enhancement or deficit of star formation on a spaxel-by-spaxel basis relative to the resolved main sequence, we investigate the SFR profiles of 864 galaxies as a function of their position relative to the global star-forming main sequence (ΔSFR). For galaxies above the global main sequence (positive ΔSFR) ΔΣSFR is elevated throughout the galaxy, but the greatest enhancement in star formation occurs at small radii (<3 kpc, or 0.5Re). Moreover, galaxies that are at least a factor of 3 above the main sequence show diluted gas phase metallicities out to 2Re, indicative of metal-poor gas inflows accompanying the starbursts. For quiescent/passive galaxies that lie at least a factor of 10 below the star-forming main sequence, there is an analogous deficit of star formation throughout the galaxy with the lowest values of ΔΣSFR in the central 3 kpc. Our results are in qualitative agreement with the `compaction' scenario in which a central starburst leads to mass growth in the bulge and may ultimately precede galactic quenching from the inside-out.

A Comparison of Conjoint Analysis Response Formats

Treesearch

Kevin J. Boyle; Thomas P. Holmes; Mario F. Teisl; Brian Roe

2001-01-01

A split-sample design is used to evaluate the convergent validity of three response formats used in conjoint analysis experiments. WC investigate whether recoding rating data to rankings and choose-one formats, and recoding ranking data to choose one. result in structural models and welfare estimates that are statistically indistinguishable from...

Standard free energy of formation of iron iodide

NASA Technical Reports Server (NTRS)

Khandkar, A.; Tare, V. B.; Wagner, J. B., Jr.

1983-01-01

An experiment is reported where silver iodide is used to determine the standard free energy of formation of iron iodide. By using silver iodide as a solid electrolyte, a galvanic cell, Ag/AgI/Fe-FeI2, is formulated. The standard free energy of formation of AgI is known, and hence it is possible to estimate the standard free energy of formation of FeI2 by measuring the open-circuit emf of the above cell as a function of temperature. The free standard energy of formation of FeI2 determined by this method is -38784 + 24.165T cal/mol. It is estimated that the maximum error associated with this method is plus or minus 2500 cal/mol.