3,959 research outputs found
Justice for Rodney King
May 1992 letter from three Howard University School of Law students to President George H.W. Bush advocating that the United States Department of Justice invoke the Petite Policy to initiate a criminal action against the Los Angeles Police Department police officers responsible for brutally beating Rodney King despite the fact that these offers had been acquitted in a California state court. The letter, which was read in front of the White House by Thomas Mitchell to hundreds of people who had gathered to urge the federal government to take action, sets forth a clear legal basis to permit the Justice Department to prosecute those responsible for the trampling of Rodney King\u27s civil rights
Questioning scrutiny:The effect of Prime Minister’s Questions on citizen efficacy and trust in parliament
This is an Accepted Manuscript of an article published by Taylor & Francis in The Journal of Legislative Studies on 2020-12-11, available online: https://www.tandfonline.com/10.1080/13572334.2020.1850010. Deposited by shareyourpaper.org and openaccessbutton.org. We've taken reasonable steps to ensure this content doesn't violate copyright. However, if you think it does you can request a takedown by emailing [email protected]
Metallurgical Structures of As-Cast and Heat-Treated High-Palladium Dental Alloys
Scanning electron microscope observations and energy-dispersive spectroscopic analyses have been performed on two first-generation and two second-generation high-palladium dental casting alloys. A specimen design simulating a maxillary central incisor coping was employed to conserve metal, while providing thin and thick sections to yield a range of solidification rates. The alloys were centrifugally cast in air, following standard dental laboratory techniques; three castings were prepared for each alloy. Each casting was sectioned to produce two mirror-image specimens, and one specimen received the appropriate oxidation heat treatment, followed by a simulated full porcelain firing sequence. After metallographic polishing, specimens were examined with a scanning electron microscope. The as-cast alloys displayed multi-phase microstructures which could be explained by the rapid solidification conditions and the relevant phase diagrams. The simulated porcelain firing heat treatment caused a variety of bulk microstructural changes in the coping sections, along with formation of complex subsurface oxidation regions which were less thick for the second-generation alloys. Elemental compositions of the palladium solid solution matrix in the heat-treated alloys were in good agreement with nominal alloy compositions provided by the manufacturers. Ruthenium-rich particles found in the microstructures of three alloys are consistent with a proposed mechanism for grain refinement
Metallurgical Structures of As-Cast and Heat-Treated High-Palladium Dental Alloys
Scanning electron microscope observations and energy-dispersive spectroscopic analyses have been performed on two first-generation and two second-generation high-palladium dental casting alloys. A specimen design simulating a maxillary central incisor coping was employed to conserve metal, while providing thin and thick sections to yield a range of solidification rates. The alloys were centrifugally cast in air, following standard dental laboratory techniques; three castings were prepared for each alloy. Each casting was sectioned to produce two mirror-image specimens, and one specimen received the appropriate oxidation heat treatment, followed by a simulated full porcelain firing sequence. After metallographic polishing, specimens were examined with a scanning electron microscope. The as-cast alloys displayed multi-phase microstructures which could be explained by the rapid solidification conditions and the relevant phase diagrams. The simulated porcelain firing heat treatment caused a variety of bulk microstructural changes in the coping sections, along with formation of complex subsurface oxidation regions which were less thick for the second-generation alloys. Elemental compositions of the palladium solid solution matrix in the heat-treated alloys were in good agreement with nominal alloy compositions provided by the manufacturers. Ruthenium-rich particles found in the microstructures of three alloys are consistent with a proposed mechanism for grain refinement
ENHANCING MODEL SECURITY: LEVERAGING USER-GENERATED IDS AS EMBEDDED WATERMARKS IN MACHINE LEARNING MODELS
The potential theft or unauthorized use of machine learning models developed by a company can lead to significant financial losses and damage to the company\u27s intellectual property. While existing methods of protecting machine learning models such as encryption or access controls can be circumvented by skilled attacker, techniques presented herein involve the integration of embedded watermarks into machine learning models. Such techniques involving the integration of embedded watermarks may not only uniquely identify a model but may also include a unique user identification/identity that can make it possible to track usage of the model and detect any unauthorized use of the model. Thus, if a model is leaked, redistributed, or misused, the watermark for the model makes it possible to identify a source of the leak/misuse, allowing for better traceability and accountability
Room Temperature Aging of Pd-Cu-Ga Dental Alloys
Specimens of three Pd-Cu-Ga dental alloys cast five years ago and subsequently stored at room temperature were reexamined and observed to have lower amounts of the eutectic constituents in the near-surface region than originally present, along with other microstructural changes. This previously unreported room temperature aging behavior of these alloys is attributed to the presence of high-diffusivity paths in the non-equilibrium ascast eutectic structures and to the essential role of the surface for the vacancy diffusion mechanism. These results may have important clinical significance for the ill vivo corrosion resistance and long-term biocompatibility of the Pd-Cu-Ga alloys
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Vortex splitting on a planetary scale in the stratosphere by cyclogenesis on a subplanetary scale in the troposphere
It is hypothesized that a splitting of the stratospheric polar vortex and a sudden warming can result when the polar vortex is elongated and a closed cyclonic circulation develops on a subplanetary scale in the troposphere beneath one of its tips. The hypothesis is supported by studying the splitting event in the Southern Hemisphere during spring 2002. Potential vorticity inversion and an inverse modelling technique using the adjoint of a fully nonlinear dynamical model are used to confirm that splitting is sensitive to subplanetary-scale cyclogenesis when it is strong. Examples of stratospheric vortex-splitting events in the Northern Hemisphere are consistent with the hypothesis. The proposed mechanism for splitting contrasts with the commonly accepted one that it is caused by the upward propagation of a planetary wave from the troposphere. It is suggested that the phenomenon is better understood as an example of a vortex interaction rather than as a wave–mean flow interaction
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Vegetation and climate of the northwest coast of North America during the last 500 K.Y. : high–resolution pollen evidence from the northern California margin
Pollen analyses of sediments from Holes 1019C, 1019E, 1020C, and 1020D as well as piston Core EW9504-17 provide
continuous, chronostratigraphically controlled proxy vegetation and climate data for coastal northwest North America for the
last ~500 k.y. Systematic changes in the representation of the diagnostic components of northern California plant assemblages
clearly show orbital-scale variations. Interglacials are all marked by an abrupt increase in alder followed by expansion of lowland
oak woodland and redwood forests. Glacials are dominated by montane forest and woodland assemblages. This sequence
reflects large-scale climatic controls (e.g., orbital-scale variation in insolation and Northern Hemisphere ice sheets) in western
North America over the last five glacial cycles. Regional climatic control (variations in sea-surface conditions) is implied by
the differential development of xeric oak and mesic redwood communities
Chronology and geochemistry of the Caribbean Large Igneous Province in Jamaica
Jamaica has a complex geological history with rocks belonging to the Cretaceous Caribbean Large Igneous Province (CLIP) in the east and Cretaceous oceanic island arc rocks in the centre and west. We present a new geochemical dataset for the CLIP and correlate this dataset and previous datasets using radiolarians and planktic foraminifers to the geological timescale. The palaeontological dating indicates that two phases of plateau activity – ‘main’ phase in the late Turonian-mid Coniacian (c. 92-87 Ma) and an ‘extended’ phase in the Coniacian to mid Campanian (c. 88-75 Ma). These phases are also seen in the Beata Ridge and on the Lower Nicaragua Rise. The geochemistry indicates that both phases are typical large igneous province plateau basalts. The ‘main’ phase has slightly more depleted light rare earth elements than the extended phase, indicating mantle source heterogeneity, and a (Sm/Yb)n >1 indicates a deeper average depth of melting for the ‘main’ phase. The association of the basalts with sediments containing specific microfossil assemblages clearly demonstrates the existence of these two magmatic phases in Jamaica
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Patterns of CaCO₃deposition in the eastern tropical Pacific Ocean for the last 150 kyr: Evidence for a southeast Pacific depositional spike during marine isotope stage (MIS) 2
We constructed biogenic mass accumulation rate (MAR) time series for eastern Pacific core transects across the equator at ~105˚and ~85˚W and along the equator from 80˚to 140˚W. We used empirical orthogonal function (EOF) analysis to extract spatially coherent patterns of CaCO₃deposition for the last 150 kyr. EOF mode 1 (51% variance) is a CaCO₃ MAR spike centered in marine oxygen isotope stage 2 (MIS 2) found under the South Equatorial Current. EOF mode 2 (19% of variance) is high north of the equator. EOF mode 3 (9% of variance) is an east-west mode centered along the North Equatorial Counter Current. The MIS 2 CaCO₃spike is the largest event in the eastern Pacific for the last 150 kyr: CaCO₃MARs are 2–3 times higher at 18 ka than elsewhere in the record, including MIS 6. It is caused by high CaCO₃ production rather than minimal dissolution. EOF 2, while it resembles deep water flow patterns, nevertheless, shows coherence to Corg deposition and is probably also driven by CaCO₃production
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