142 Matching Results

Search Results

Advanced search parameters have been applied.

in publisher: "The Observatory"

open access

The Discovery of a Nearby M Dwarf

This article reports the serendipitous discovery of a nearby M dwarf star, found while observing the old nova DN Gem at the Wise Observatory.

Date: April 1999

Creator: Shemmer, Ohad & Kaspi, Shai

Item Type: Article

Partner: UNT College of Arts and Sciences

open access

Theoretical studies of highly ionized species. Progress report, March 1, 1977--February 28, 1978

The relativistic random phase approximation has been used to study the helium, beryllium, magnesium and zinc isoelectronic sequences. Model potential methods have been employed to study multi-photon ionization of sodium from the ground and excited states. Forbidden decays in the Be and Mg isoelectronic sequences have been investigated. The 1s2p/sup 2/ /sup 2/P and 1s2p/sup 2/ /sup 2/D states of lithium-like ions have been studied. Calculations of radiative charge transfer have been carried out.

Date: November 1, 1977

Creator: Dalgarno, A. & Victor, G.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Theoretical studies of highly ionized species. Progress report, March 1, 1978--February 28, 1979. [Summary of research activities at Harvard College Observatory]

The relativistic random phase approximation was used to study discrete outer and inner shell transitions of the neon isoelectronic sequence, and to calculate photoionization cross sections of elements of the magnesium and zinc isoelectronic sequences. Model potentials were constructed for the copper and zinc isoelectronic sequences. Molecular processes were investigated, and the possibility of an enhanced radiative recombination rate for molecular ions was demonstrated. Detailed calculations of… more

Date: November 1, 1978

Creator: Dalgarno, A. & Victor, G.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Theoretical studies of highly ionized species. Progress report, March 1, 1979-February 28, 1980

Applications were continued of the relativistic random phase approximation and of the model potential method and the properties of highly stripped ionic systems were calculated. Charge transfer recombination and ionization were identified as important processes in plasmas and calculations were performed of rate coefficients for several systems at thermal energies. A theory was constructed of collision-induced fine-structure transitions involving protons and the interaction potentials for O/sup … more

Date: November 1, 1979

Creator: Dalgarno, A. & Victor, G.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Theoretical studies of highly ionized species. Progress report, March 1, 1978--February 28, 1979. [Summaries of research activities at Harvard College Observatory]

The relativistic random phase approximation was used to study discrete outer and inner shell transitions of the neon isoelectronic sequence, and to calculate photoionization cross sections of elements of the magnesium and zinc isoelectronic sequences. Model potentials were constructed for the copper and zinc isoelectronic sequences. Molecular processes were investigated and the possibility of an enhanced radiative recombination rate for molecular ions was demonstrated. Detailed calculations of … more

Date: November 1, 1978

Creator: Dalgarno, A. & Victor, G.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Theoretical studies of highly ionized species. Progress report, March 1, 1976--February 28, 1977. [Summaries of research activities at Harvard College Observatory]

A relativistic generalization of the random phase approximation was developed that permits the nonperturbative incorporation of relativistic effects and extends the theory to allowed and forbidden transitions of all multipolarities. Calculations for E1 (2/sup 1/,/sup 3/P/sub 1/-/sup 1/S/sub 0/), M1 (2/sup 3/S/sub 1/-1/sup 1/S/sub 0/) and M2 (2/sup 3/P/sub 2/-1/sup 1/S/sub 0/) transitions in the helium isoelectronic sequence for Z up to 100 were carried out, as well as transitions between excite… more

Date: November 1, 1976

Creator: Dalgarno, A. & Victor, G. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Theoretical studies of highly ionized species. Progress report, March 1, 1980-February 28, 1981

The calculations of the charge transfer recombination and ionization rate coefficients for a wide range of ionic systems in collision with hydrogen and helium at thermal energies were completed. For the carbon ions in hydrogen, the calculations were extended to energies of 100 eV. The importance of the processes in ionized plasmas was demonstrated by studies of the solar corona and of shock waves. Preliminary results were obtained on cross sections for the excitation of fine structure transitio… more

Date: October 1, 1980

Creator: Dalgarno, A. & Victor, G.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Remarks by Administrator O'Keefe at the Earth Observation Summit

Remarks by NASA Administrator Sean O'Keefe at the 2003 Earth Observation Summit in Washington, DC. The purpose of the summit was to promote the development of a comprehensive, coordinated, and sustained Earth observation system or systems among governments and the international community to understand and address global environmental and economic challenges, and also to begin a process to develop a conceptual framework and implementation plan for building this integrated Earth observation sys… more

Date: July 31, 2003

Creator: O'Keefe, Sean

Item Type: Text

Partner: UNT Libraries

open access

Ozone

Although it represents only a tiny fraction of the atmosphere, ozone is crucial for life on Earth. Depending on where ozone resides, it can protect or harm life on Earth.

Date: 2002

Creator: NASA Earth Observatory

Item Type: Text

Partner: UNT Libraries

open access

Ozone

In the stratosphere, ozone is created primarily by ultraviolet radiation. When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone. There is so much oxygen in our atmosphere, that these high-energy ultraviolet rays are completely absorbed in the stratosphere.

Date: 2002

Creator: NASA Earth Observatory

Item Type: Text

Partner: UNT Libraries

open access

Ozone

The term "ozone depletion" means more than just the natural destruction of ozone, it means that ozone loss is exceeding ozone creation.

Date: 2002

Creator: NASA Earth Observatory

Item Type: Text

Partner: UNT Libraries

open access

Ozone

The amount and distribution of ozone molecules in the stratosphere varies greatly over the globe. Ozone molecules are transported around the stratosphere much as water clouds are transported in the troposphere. Therefore, scientists observing ozone fluctuations over just one spot could not know whether a change in local ozone levels meant an alteration in global ozone levels, or simply a fluctuation in the concentration over that particular spot. Satellites have given scientists the ability to … more

Date: 2002

Creator: NASA Earth Observatory

Item Type: Text

Partner: UNT Libraries

open access

Highways of a Global Traveler: Tracking Tropospheric Ozone

On the stage of global change, ozone plays the role of both hero and villain. This brief document discusses about the tracking of Tropospheric Ozone, where ozone forms and where it travels have become key concerns for international health and economic policy-making.

Date: March 22, 2002

Creator: Allen, Jeannie & Simmon, Robert

Item Type: Text

Partner: UNT Libraries

open access

Measurements of the total CO[sub 2] concentration and partial pressure of CO[sub 2] in seawater during WOCE expeditions in the South Pacific Ocean

During the first year of the grant, we participated in three WOCE expeditions (a total of 152 days at sea) in the South Pacific Ocean, and the field phase of the proposed investigation has been successfully completed. The total CO[sub 2] concentration and pCO[sub 2] were determined at sea in 4419 water samples collected at 422 stations. On the basis of the shipboard analyses of SIO Reference Solutions for CO, and a comparison with the results of previous expeditions, the overall precision of ou… more

Date: June 29, 1993

Creator: Takahashi, T.; Goddard, J. G.; Chipman, D. W. & Rubin, S. I.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Department of Energy quarterly technical report

The objective is to test the concept that the growth faults in Eugene Island Block 330 (EI-330 field) are conduits through which producing reservoirs are charged and that enhanced production can be developed by producing directly from the fault zone. The site, operated by Penzoil, is located in 250 feet of water and the productive depth intervals include 4000 to 9000 feet. The field demonstration will be accomplished by drilling and production testing of growth fault systems associated with the… more

Date: April 15, 1995

Creator: Anderson, R. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Determination of ocean/atmosphere carbon dioxide flux within OMP survey area. Final technical progress report, June, 1 1993--May 31, 1995

Determination of the net flux of atmospheric CO{sub 2} with the ocean at the continental margin is one of the three principal goals of the Ocean Margins Program. The work reported here represents the initial phase of that determination, as carried out during two cruises within the OMP survey area in 1993 and 1994. The interannual variability was addressed through the occupation of hydrographic stations of nearly identical location one year apart, while the spatial variability in the air-sea PCO… more

Date: October 17, 1995

Creator: Chipman, D. W. & Takahashi, T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Steady-state and transient modeling of tracer and nutrient distributions in the global ocean. Final report, August 1, 1993--July 31, 1995

The authors have completed the studies using the inorganic carbon cycle in the zonally averaged ocean circulation model to calculate anthropogenic uptake of CO{sub 2} and bomb radiocarbon. While the results are in broad agreement with previous studies, the authors have learned that horizontal mixing processes due to gyre circulation are important for transient tracer experiments over a few decades. Using the inorganic carbon cycle model the authors have started to look at the distributions of {… more

Date: May 17, 1998

Creator: Stocker, T. F.; Lynch-Stieglitz, J. & Broecker, W. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Geochemical constraints on ocean general circulation models. Final report, May 1, 1995--April 30, 1997

A better understanding of the manner in which the ocean operates is essential to the preparation for the consequences of the generation of CO{sub 2} by fossil fuel burning. Examples are as follows: (1) the ocean will ultimately take up a major fraction of the CO{sub 2} produced, but this uptake is retarded by the slow mixing rates, in order to predict the uptake, researchers must develop and validate general circulation models for the ocean; (2) during glacial time large global climate changes … more

Date: May 17, 1998

Creator: Broecker, W. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Distribution of marine birds on the mid- and North-Atlantic US outer continental shelf. Technical progress report, January 1978-July 1980

The species composition, distribution, and abundance of marine birds on continental shelf waters from Cape Hatteras to the Bay of Fundy were examined using ships-of-opportunity. Northern Fulmar, Cory's Shearwater, Greater Shearwater, Sooty Shearwater, Wilson's Storm-Petrel, Gannet, Red Phalarope, Great Black-backed Gull, Herring Gull, and Black-legged Kittiwake were the most abundant and common species. These species were ecologically dominant within the bird community in numbers and biomass. G… more

Date: September 1, 1980

Creator: Powers, K.D.; Pittman, G.L. & Fitch, S.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Relationship of marine birds to oceanic fronts off the northeastern United States. Technical progress report, April-November 1981

The role of fronts as determinants of pelagic distributions of zooplankton-feeding marine birds off the northeastern United States was investigated. Our analyses suggest that the shelf/slope and Cape Cod fronts are not convergent features, which accumulate biological or probably inorganic materials at the surface. Instead, our data support previous oceanographic studies, which implicate enhanced vertical mixing in the shelf-break region and along northern Georges Bank. This conclusion supports … more

Date: November 1, 1981

Creator: Powers, K. D. & Backus, E. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Distribution of marine birds on the mid- and north-Atlantic U. S. outer continental shelf. Technical progress report, September 1978-August 1979

The scope of the project was not changed since the last annual report, but the study area was extended south to Cape Hatteras. The objectives were to determine spatial and temporal distributions of marine birds in mid- and north-Atlantic U.S. continental shelf waters; to identify marine bird food habits and distribution of prey items; and (3) to develop a marine bird data retrieval bank. Data from 1978-79 indicated that Georges Bank and its adjacent waters support an abundant and diverse bird p… more

Date: October 1, 1979

Creator: Powers, K.D.; Pittman, G.L. & Burrell, G.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Distribution of marine birds on Georges Bank and Adjacent waters. Progress report No. 2, April--June 1978

From 27 March to 20 June 1978, 7 cruises aboard U.S. Coast Guard cutters DECISIVE, VIGILANT, and VIGOROUS and the National Marine Fisheries Service research vessel ALBATROSS IV were made on outer continental shelf waters in regions from the mid-Atlantic to the Gulf of Maine and Scotian Shelf. A total of 13916 marine birds of at least 27 species were counted in 711.16 km/sup 2/ sampled from 730 fixed-area transects (300m wide by 10 minutes cruising time). An equal number of 10-minute total bird … more

Date: July 1, 1978

Creator: Powers, K.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Distribution of marine birds on Georges Bank and adjacent waters. Technical progress report, 1 January--31 August 1978

The work accomplished during the period covered in this technical progress report demonstrates the importance, interest, and necessity of a distribution study of marine birds in the Georges Bank area on a national and international scale. Cooperation was extended by the U.S. National Marine Fisheries Service, U.S. Fish and Wildlife Service, U.S. Coast Guard, and by the Canadian Wildlife Service, Halifax, N.S., AltantNIRO, Kaliningrad, USSR, and Federal Republic of Germany. Two sampling methods,… more

Date: October 1, 1978

Creator: Powers, K.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Distribution of marine birds on Georges Bank and adjacent water. Progress report No. 3, July--September 1978

From 21 June to 16 September 1978, 8 cruises aboard U.S. and Canada Coast Guard cutters and research vessels from the National Marine Fisheries Service and AtlantNIRO, Kaliningrad, USSR were made in the following areas: U.S. mid- and north-Atlantic continental shelf, western North Atlantic basin, Atlantic Canada, and Hudson Strait and Bay. Excluding those Canadian areas sampled, 18, 136 marine birds of 22 species were counted in 941.99 km/sup 2/ sampled from 1002 fixed-area transects. An equal … more

Date: October 1, 1978

Creator: Powers, K.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department