6,307 research outputs found
From the Arctic to the Tropics: The U.S. UNCLOS Bathymetric Mapping Program
Since CHC2006, the University of New Hampshireâs Center for Coastal & Ocean Mapping/Joint Hydrographic Center has mapped with multibeam, the bathymetry of an additional ~220,000 km2 of seafloor in areas as diverse as the Arctic, the Northern Marianas of the western Pacific and the Gulf of Mexico. The mapping supports any potential U.S. submission for of extended continental shelves under Article 76 of the United Nations Convention of the Law of the Sea. Consequently, the mapping has concentrated on capturing the complete extent of the 2500-m isobath and the zone where the Article 76-defined foot of the slope exists. In practice, the complete area between ~1500 and ~4500 m water depths is mapped in each region (with the exception of the Arctic Ocean). The data have been collected in conditions that range from harsh Arctic sea ice to the calms of the Philippine Sea tropics. Although, some of the conditions have limited the quality of some of the data, the data quality is generally quite good and geological surprises have been uncovered on each of the cruises
Mapping in the Arctic Ocean in Support of a Potential Extended Continental Shelf
Under Article 76 of The United Nations Convention on the Law of the Sea (UNCLOS; U.N. 1997), coastal states may, under certain circumstances, gain sovereign rights over the resources of the seafloor and subsurface of âsubmerged extensions of their continental marginâ beyond the recognized 200 nautical mile (nmi) limit of their Exclusive Economic Zone (EEZ). The establishment of an âextended continental shelfâ (ECS) under Article 76 involves the demonstration that the area of the ECS is a ânatural prolongationâ of a coastal stateâs territorial landmass and then the application of a series of formulae and limit lines that are based on determination of the âfoot of the slope,â (defined in Article 76 as the maximum change in gradient at itâs base), the underlying sediment thickness, and the locations of the 2500 m isobath and the 350 nmi line from the territorial sea base line. Although the United States has not yet acceded to the UNCLOS, increasing recognition that implementation of Article 76 could confer sovereign rights over large and potentially resource-rich areas of the seabed beyond its current 200 nautical mile (nmi) limit has renewed interest in the potential for accession to the treaty and spurred U.S. efforts to map area of potential âextended continental shelfâ
High Resolution Mapping in support of UNCLOS Article 76: Seeing the seafloor with new eyes
Since 2003, the Center for Coastal & Ocean Mapping/Joint Hydrographic Center at the University of New Hampshire (UNH) has been conducting multibeam mapping of many U.S. continental margins in areas where there is a potential for an extended continental shelf as defined under Article 76 of the United Nations Convention on the Law of the Sea. UNH was directed by Congress, through funding by the National Oceanic & Atmospheric Administration, to map the bathymetry in areas in the Arctic Ocean, Bering Sea, Gulf of Alaska, Northwest Atlantic, northern Gulf of Mexico, the Northern Mariana Islands, Kingman Reef and Palmyra Atoll (Fig. 1). The purpose of these surveys is to accurately locate the 2500-m isobath and to collect the bathymetry data required to eventually determine the location of the maximum change in gradient on Figure 1. Locations and year of bathymetry mapping (yellow areas) for U.S. UNCLOS concerns. the continental rises. A total area of about 862,000 km2 has been completed; approximately 250,000 km2 remains to be mapped. The area between the ~1000 and ~4800-m isobaths has been mapped on each of the completed margins. The mapping has been conducted with multibeam echosounders (MBES) that typically collect soundings with a spacing of ~50 m or less in the focused water depths. After each area is mapped, the data are gridded at 100-m spatial resolution although higher resolution is possible in the shallower regions. The depth precision achieved on all of the cruises has been \u3c1% of the water depth and typically has been \u3c0.5% of the water depth, based on cross-line comparisons. Navigation on all of the cruises has been acquired with inertial-aided DGPS using commercial differential corrections that provide 2 position accuracies much better than ±5 m. All of the MBES systems used produce acoustic backscatter as well as bathymetry but the backscatter quality varies among systems and conditions. Table 1 is a summary of the mapping completed and of areas yet to be mapped for bathymetry. The data are all processed at sea by UNH personnel during their collection and the data, grids and views of the processed data are posted on the worldwide web soon after completion of each area. The data, grids and images can be viewed and downloaded at http://ccom.unh.edu/law_of_the_sea.html
Partial (13)C isotopic enrichment of nucleoside monophosphates: useful reporters for NMR structural studies
Analysis of the (13)C isotopic labeling patterns of nucleoside monophosphates (NMPs) extracted from Escherichia coli grown in a mixture of C-1 and C-2 glucose is presented. By comparing our results to previous observations on amino acids grown in similar media, we have been able to rationalize the labeling pattern based on the well-known biochemistry of nucleotide biosynthesis. Except for a few notable absences of label (C4 in purines and C3âČ in ribose) and one highly enriched site (C1âČ in ribose), most carbons are randomly enriched at a low level (an average of 13%). These sparsely labeled NMPs give less complex NMR spectra than their fully isotopically labeled analogs due to the elimination of most (13)Câ(13)C scalar couplings. The spectral simplicity is particularly advantageous when working in ordered systems, as illustrated with guanosine diphosphate (GDP) bound to ADP ribosylation factor 1 (ARF1) aligned in a liquid crystalline medium. In this system, the absence of scalar couplings and additional long-range dipolar couplings significantly enhances signal to noise and resolution
Angular momentum transport and disk morphology in SPH simulations of galaxy formation
We perform controlled N-Body/SPH simulations of disk galaxy formation by
cooling a rotating gaseous mass distribution inside equilibrium cuspy spherical
and triaxial dark matter halos. We systematically study the angular momentum
transport and the disk morphology as we increase the number of dark matter and
gas particles from 10^4 to 10^6, and decrease the gravitational softening from
2 kpc to 50 parsecs. The angular momentum transport, disk morphology and radial
profiles depend sensitively on force and mass resolution. At low resolution,
similar to that used in most current cosmological simulations, the cold gas
component has lost half of its initial angular momentum via different
mechanisms. The angular momentum is transferred primarily to the hot halo
component, by resolution-dependent hydrodynamical and gravitational torques,
the latter arising from asymmetries in the mass distribution. In addition,
disk-particles can lose angular momentum while they are still in the hot phase
by artificial viscosity. In the central disk, particles can transfer away over
99% of their initial angular momentum due to spiral structure and/or the
presence of a central bar. The strength of this transport also depends on force
and mass resolution - large softening will suppress the bar instability, low
mass resolution enhances the spiral structure. This complex interplay between
resolution and angular momentum transfer highlights the complexity of
simulations of galaxy formation even in isolated haloes. With 10^6 gas and dark
matter particles, disk particles lose only 10-20% of their original angular
momentum, yet we are unable to produce pure exponential profiles.Comment: 17 pages, 16 figures, MNRAS accepted. Minor changes in response to
referee comments. High resolution version of the paper can be found at
http://krone.physik.unizh.ch/~tkaufman/papers.htm
A Structural Equation Modeling-Based Examination of the Private Label Brand (PLB) Consumer Evaluation Process
The goal of this paper is to answer the question âWhat variables influence consumer private label brand (PLB) evaluations?â We employ structural equation modeling (SEM) in order to analyze a hypothesized process by which consumer-based evaluations of retailer and product category, along with perceived risk of the category and PLB all affect the ultimate PLB brand evaluation. PLBs have been heavily researched in academic marketing research journals but SEM-based research is minimal. Research has generally been conducted using model-building techniques which are then empirically tested using real-world data. Given the complexity of the process, an alternate approach is to use experimental techniques to gain first-hand PLB data and then analyze it using appropriate methodology. The current project represents a step in that direction. While the model is subject to limitations that call its utility into question, it does provide guidance for a future, more theoretically-sound a priori model and resulting SEM analysis
Hebrews- An Exegetical Study
In my sketch of the conception of the Christian High-Priest found in Hebrews. I shall consider in the first part the person of Christ as suited to His High-priesthood, and in the second part Christ as performing the work of a High-priest. I shall stress the special emphasis of Christ as OFFERER and the OFFERING which He Brings. A comparison of the Christian High-priest with the high-priests under the Old Dispensation will not be dealt with in a separate chapter, but will be drawn incidentally as the argument progresses
Seafloor mapping in the Arctic: support for a potential U.S. extended continental shelf
For the United States, the greatest opportunity for an extended continental shelf under UNCLOS is in the ice-covered regions of the Arctic north of Alaska. Since 2003, CCOM/JHC has been using the icebreaker Healy equipped with a multibeam echosounder, chirp subbottom profiler, and dredges, to map and sample the region of Chukchi Borderland and Alpha-Mendeleev Ridge complex. These data have led to the discovery of several new features, have radically changed our view of the bathymetry and geologic history of the area, and may have important ramifications for the determination of the limits of a U.S. extended continental shelf under Article 76
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