6,147 research outputs found
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Overview of Constitutional Challenges to NSA Collection Activities and Recent Developments
[Excerpt] Beginning in the summer of 2013, media reports of foreign intelligence activities conducted by the National Security Agency (NSA) have been published and are apparently based on unauthorized disclosures of classified information by Edward Snowden, a former NSA contractor. The reports have focused on two main NSA collection activities conducted under the auspices of the Foreign Intelligence Surveillance Act (FISA) of 1978. The first is the bulk collection of telephony metadata for domestic and international telephone calls. The second involves the interception of Internet-based communications and is targeted at foreigners who are not within the United States, but may also inadvertently acquire the communications of U.S. persons.
As the public’s awareness of these programs has grown, Members of Congress and the public have increasingly voiced concerns about the constitutionality of these programs. This report provides a description of these two programs and the various constitutional challenges that have arisen in judicial forums with respect to each. Although a brief overview of the constitutional arguments and issues raised in the assorted cases is included, a detailed analysis or evaluation of those arguments is beyond the scope of this report
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Requiring Individuals to Obtain Health Insurance: A Constitutional Analysis
[Excerpt] This report analyzes certain constitutional issues raised by requiring individuals to purchase health insurance under Congress’s authority under its taxing power or its power to regulate interstate commerce. It also addresses whether the exceptions to the minimum coverage provision to purchase health insurance satisfy First Amendment freedom of religion protections. Finally, this report discusses some of the more publicized legal challenges to ACA, as well additional issues that are currently before the Court
Poverty, Food Insecurity and Nutritional Deprivation in Rural China: Implications for Children\u27s Literacy Achievement
Globally, food insecurity is a significant contextual aspect of childhood. About 850 million people were undernourished worldwide during the period 2006 to 2008, including 129.6 million people, or 10 percent of the population, in China (FAO 2011:45‐46). Implications of food insecurity for children\u27s schooling in developing country contexts are poorly understood. Analyses of a survey of children from 100 villages in northwest China show that long‐term undernourishment and food insecurity strike the poorest disproportionately, but not exclusively; long‐term undernourishment matters for literacy via early achievement; and, after adjusting for socioeconomic status, long‐term undernourishment, and prior achievement, food insecure children have significantly lower literacy scores
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Complex macrocycle exploration: parallel, heuristic, and constraint-based conformer generation using ForceGen.
ForceGen is a template-free, non-stochastic approach for 2D to 3D structure generation and conformational elaboration for small molecules, including both non-macrocycles and macrocycles. For conformational search of non-macrocycles, ForceGen is both faster and more accurate than the best of all tested methods on a very large, independently curated benchmark of 2859 PDB ligands. In this study, the primary results are on macrocycles, including results for 431 unique examples from four separate benchmarks. These include complex peptide and peptide-like cases that can form networks of internal hydrogen bonds. By making use of new physical movements ("flips" of near-linear sub-cycles and explicit formation of hydrogen bonds), ForceGen exhibited statistically significantly better performance for overall RMS deviation from experimental coordinates than all other approaches. The algorithmic approach offers natural parallelization across multiple computing-cores. On a modest multi-core workstation, for all but the most complex macrocycles, median wall-clock times were generally under a minute in fast search mode and under 2 min using thorough search. On the most complex cases (roughly cyclic decapeptides and larger) explicit exploration of likely hydrogen bonding networks yielded marked improvements, but with calculation times increasing to several minutes and in some cases to roughly an hour for fast search. In complex cases, utilization of NMR data to constrain conformational search produces accurate conformational ensembles representative of solution state macrocycle behavior. On macrocycles of typical complexity (up to 21 rotatable macrocyclic and exocyclic bonds), design-focused macrocycle optimization can be practically supported by computational chemistry at interactive time-scales, with conformational ensemble accuracy equaling what is seen with non-macrocyclic ligands. For more complex macrocycles, inclusion of sparse biophysical data is a helpful adjunct to computation
In-situ Lock-in Thermographic Measurement Of Powder Layer Thermal Diffusivity And Thickness In Laser Powder Bed Fusion
The thermal transport properties of the powder layer play a crucial role in the process of laser powder bed fusion (LPBF). This paper introduces an in-situ measurement method utilizing active lock-in infrared thermography (LIT) to determine the thermal diffusivity and thickness of the powder layer. The proposed method exhibits great potential for accurate powder property and thickness measurements and real-time process monitoring. In this lock-in thermographic technique, the LPBF laser beam is directed through an optical diffuser and modulated into a square thermal wave. This thermal wave serves as an active heat source to heat the surface of the powder bed. The surface temperature response is captured using a long-wave infrared (LWIR) camera. A one-dimensional thermal model is employed to provide insights into heat transfer in the frequency domain. The frequency-dependent phase response of temperature is influenced by the effective thermal diffusivity and thickness of the powder layer. This model is validated experimentally first and then utilized to measure the thermal diffusivity of different powder layers created using various particle sizes and wiper spreading speeds. Larger particle size and slower wiper spreading speed are shown to produce higher thermal diffusivity. Finally, the paper shows how this technique can be used to measure the powder layer thickness over printed geometries. This capability enables the detection of deviations in the fused part surface or errors in the wiper through analysis of resulting variations in the powder. These findings highlight the potential of the lock-in thermographic technique for rapid in-situ inspection of the new powder layer in laser powder bed fusion (LPBF) processes
Tunable Low Density Palladium Nanowire Foams
Nanostructured palladium foams offer exciting potential for applications in
diverse fields such as catalyst, fuel cell, and particularly hydrogen storage
technologies. We have fabricated palladium nanowire foams using a cross-linking
and freeze-drying technique. These foams have a tunable density down to 0.1% of
the bulk, and a surface area to volume ratio of up to 1,540,000:1. They exhibit
highly attractive characteristics for hydrogen storage, in terms of loading
capacity, rate of absorption and heat of absorption. The hydrogen
absorption/desorption process is hysteretic in nature, accompanied by
substantial lattice expansion/contraction as the foam converts between Pd and
PdHx.Comment: 17 pages, 4 figure
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Amendments to the Foreign Intelligence Surveillance Act (FISA) Set to Expire May 27, 2011
This report discusses the Foreign Intelligence Surveillance Act (FISA) which provides a statutory framework by which government agencies may, when gathering foreign intelligence investigation, obtain authorization to conduct electronic surveillance or physical searches, utilize pen registers and trap and trace devices, or access specified business records and other tangible things. Authorization for such activities is typically obtained via a court order from the Foreign Intelligence Surveillance Court (FISC), a specialized court created to act as a neutral judicial decision maker in the context of FISA
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Amendments to the Foreign Intelligence Surveillance Act (FISA) Set to Expire May 27, 2011
This report discusses the Foreign Intelligence Surveillance Act (FISA) which provides a statutory framework by which government agencies may, when gathering foreign intelligence investigation, obtain authorization to conduct electronic surveillance or physical searches, utilize pen registers and trap and trace devices, or access specified business records and other tangible things. Authorization for such activities is typically obtained via a court order from the Foreign Intelligence Surveillance Court (FISC), a specialized court created to act as a neutral judicial decision maker in the context of FISA
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