1,075 research outputs found
The Changing Environment of Urban Development PolicyâShared Power or Shared Impotence?
In this Article we highlight five recent trends that have profoundly transformed the shared power system of American urban government as it relates to that arena of urban development in which we have been active over the past half-dozen years: transportation
Trajectory shifts in the Arctic and Subarctic freshwater cycle
Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of American Association for the Advancement of Science for personal use, not for redistribution. The definitive version was published in Science 313 (2006): 1061-1066, doi:10.1126/science.1122593.Manifold changes in the freshwater cycle of high-latitude lands and oceans have
been reported in the past few years. A synthesis of these changes in sources of freshwater and in ocean freshwater storage illustrates the complementary and synoptic temporal pattern and magnitude of these changes over the past 50 years. Increasing river discharge anomalies and excess net precipitation on the ocean contributed ~20,000 km3 of fresh water to the Arctic and high latitude North Atlantic oceans from lows in the 1960s to highs in the 1990s. Sea ice attrition provided another ~15,000 km3, and glacial melt added ~2000 km3.
The sum of anomalous inputs from these freshwater sources matched the amount and rate at which fresh water accumulated in the North Atlantic during much of the period from
1965 through 1995. The changes in freshwater inputs and ocean storage occurred in
conjunction with the amplifying North Atlantic Oscillation and rising air temperatures.
Fresh water may now be accumulating in the Arctic Ocean and will likely be exported
southward if and when the North Atlantic Oscillation enters into a new high phase.Funding was provided by
NSF (grants OPP-0229302, OPP- 0436118, OPP-0327664, OPP-0352754, OPP-0519840, OCE-
0326778), ONR (grant N00014-02-1-0305) and NASA (grant IDS-03-0000-0145)
Protecting the UK Infrastructure: A System to Detect GNSS Jamming and Interference
Abstract The vulnerability of space based position navigation and timing (PNT) systems to RF interference sources is becoming well known outside of the traditional PNT sector for example, into the critical infrastructure operations area. Risk managers of organisations in this area are becoming aware of the vulnerabilities and dependencies in using space based PNT systems. This paper presents work performed and work on-going in the UK, to develop capabilities that provide detection and early warning for operators of critical infrastructure and law enforcement agencies (LEA), to the presence of RF interference in the bands associated with space based PNT. These capabilities can detect and will be able to locate source(s) of RF interference which allows infrastructure operators and LEA to take advantage of quality of service and trust concepts when applied to these space based PNT systems. This paper also presents a case study of the detection of an intentional RF interference device, which impacted upon one organisation's critical infrastructure
NASA Image eXchange (NIX)
This paper discusses the technical aspects of and the project background for the NASA Image exchange (NIX). NIX, which provides a single entry point to search selected image databases at the NASA Centers, is a meta-search engine (i.e., a search engine that communicates with other search engines). It uses these distributed digital image databases to access photographs, animations, and their associated descriptive information (meta-data). NIX is available for use at the following URL: http://nix.nasa.gov./NIX, which was sponsored by NASAs Scientific and Technical Information (STI) Program, currently serves images from seven NASA Centers. Plans are under way to link image databases from three additional NASA Centers. images and their associated meta-data, which are accessible by NIX, reside at the originating Centers, and NIX utilizes a virtual central site that communicates with each of these sites. Incorporated into the virtual central site are several protocols to support searches from a diverse collection of database engines. The searches are performed in parallel to ensure optimization of response times. To augment the search capability, browse functionality with pre-defined categories has been built into NIX, thereby ensuring dissemination of 'best-of-breed' imagery. As a final recourse, NIX offers access to a help desk via an on-line form to help locate images and information either within the scope of NIX or from available external sources
Seasonal evolution of Aleutian low pressure systems: Implications for the North Pacific subpolar circulation
The seasonal change in the development of Aleutian low pressure systems from early fall to early winter is analyzed using a combination of meteorological reanalysis fields, satellite sea surface temperature (SST) data, and satellite wind data. The time period of the study is SeptemberâDecember 2002, although results are shown to be representative of the long-term climatology. Characteristics of the storms were documented as they progressed across the North Pacific, including their path, central pressure, deepening rate, and speed of translation. Clear patterns emerged. Storms tended to deepen in two distinct geographical locationsâthe Gulf of Alaska in early fall and the western North Pacific in late fall. In the Gulf of Alaska, a quasi-permanent ânotchâ in the SST distribution is argued to be of significance. The signature of the notch is imprinted in the atmosphere, resulting in a region of enhanced cyclonic potential vorticity in the lower troposphere that is conducive for storm development. Later in the season, as winter approaches and the Sea of Okhotsk becomes partially ice covered and cold, the air emanating from the Asian continent leads to enhanced baroclinicity in the region south of Kamchatka. This corresponds to enhanced storm cyclogenesis in that region. Consequently, there is a seasonal westward migration of the dominant lobe of the Aleutian low. The impact of the wind stress curl pattern resulting from these two regions of storm development on the oceanic circulation is investigated using historical hydrography. It is argued that the seasonal bimodal input of cyclonic vorticity from the wind may be partly responsible for the two distinct North Pacific subarctic gyres
Anatomy of a Dansgaard-Oeschger warming transition: High-resolution analysis of the North Greenland Ice Core Project ice core
Large and abrupt temperature oscillations during the last glacial period, known as DansgaardâOeschger (DO) events, are clearly observed in the Greenland ice core record. Here we present a new highâresolution chemical (2 mm) and stable isotope (20 mm) record from the North Greenland Ice Core Project (NGRIP) ice core at the onset of one of the most prominent DO events of the last glacial, DOâ8, observed âŒ38,000 years ago. The unique, subannualâresolution NGRIP record provides a true sequence of change during a DO warming with detailed annual layer counting of very high depth resolution geochemical measurements used to determine the exact duration of the transition. The continental ions, indicative of longârange atmospheric loading and dustiness from East Asia, are the first to change, followed by the snow accumulation, the moisture source conditions, and finally the atmospheric temperature in Greenland. The sequence of events shows that atmospheric and oceanic source and circulation changes preceded the DO warming by several years
A guide to the South Plains of Texas
A compilation of essays and articles covering history, agriculture, educational institutions, and legends of the historic South Plains of Texas.[139] leaves ; 152 pdf pages.November 1935.Pictorial illustrations by Bess Hubbard.Mimeographed copy reproduced by the students of Lubbock High School with permission and assistance of the Texas Highway Dept.Plains of Texas / A.W. Evans -- The rock house on Blanco Canyon / R.B. Smith -- The story of the famous Old Yellow House Ranch / Lamb county news -- The T-Bar Ranch / R.B. Smith -- U-Lazy-S Ranch / E. Taylor -- The old Mackenzie Trail / W.L Chittenden -- Mackenzie's Indian campaigns on the Staked Plains / M.L. Cox -- Horse bones / R.G. Carter -- Old Man Singer's store / W.C. Holden -- Letter of long ago describes living conditions in days of first settles / M. Witt -- Shanties and dugouts / The Cattleman -- The legend of the sand hills / J. Mitchell -- Three notable landmarks in Lynn County / F.P. Hill -- Descriptions of South Plains cities and towns / V. Upton -- Elevation, population, and highway mileage maps / M.W. Hobbs -- Roadside divertissement / V. Upton
A Novel, Enriched Population Pharmacokinetic Model for Recombinant Factor VIII-Fc Fusion Protein Concentrate in Hemophilia A Patients
Background The currently published population pharmacokinetic (PK) models used for PK-guided dosing in hemophilia patients are based on clinical trial data and usually not externally validated in clinical practice. The aim of this study was to validate a published model for recombinant factor VIII-Fc fusion protein (rFVIII-Fc) concentrate and to develop an enriched model using independently collected clinical data if required. Methods Clinical data from hemophilia A patients treated with rFVIII-Fc concentrate (Elocta) participating in the United Kingdom Extended Half-Life Outcomes Registry were collected. The predictive performance of the published model was assessed using mean percentage error (bias) and mean absolute percentage error (inaccuracy). An extended population PK model was developed using nonlinear mixed-effects modeling (NONMEM). Results A total of 43 hemophilia A patients (FVIII Conclusion We concluded that the existing rFVIII-Fc population PK model is valid for patients >= 12 years. However, it is not reliable in younger patients. Our alternative model, constructed from real world patient data including children, allows for better description of patients >= 5 years
- âŠ