The benefits of one-dimensional detectors for high-pressure powder X-ray diffraction

High-pressure powder X-ray diffraction is a fundamental technique for investigating structural responses to externally applied force. Synchrotron sources and two-dimensional detectors are required. In contrast to this conventional setup, high-resolution beamlines equipped with one-dimensional detectors could offer much better resolved peaks but cannot deliver accurate structure factors because they only sample a small portion of the Debye rings, which are usually inhomogeneous and spotty because of the small amount of sample. In this study, a simple method to overcome this problem is presented and successfully applied to solving the structure of an L-serine polymorph from powder data. A comparison of the obtained high-resolution high-pressure data with conventional data shows that this technique, providing up to ten times better angular resolution, can be of advantage for indexing, for lattice parameter refinement, and even for structure refinement and solution in special cases.

Crack and powder cocaine federal legislation: A sentencing disparity and potential for policy improvement

Since its introduction into the United States in the 1980s, crack cocaine has been a harsh epidemic that has taken its toll on a countless number of people. This highly addictive, cheap and readily available drug of abuse has permeated many demographic sectors, mostly in low income, lesser educated, and urban communities. This epidemic of crack cocaine use in inner city areas across the Unites States has been described as an expression of economic marginality and “social suffering” coupled with the local and international forces of drug market economies (Agar 2003). As crack cocaine is a derivative of cocaine, it utilizes the psychoactive component of the drug, but delivers it in a much stronger, quicker, and more addictive fashion. This, coupled with its ready availability and cheap price has allowed for users to not only become very addicted very quickly, but to be subject to the stringent and sometimes unequal or inconsistent punishments for possession and distribution of crack-cocaine. ^ There are many public health and social ramifications from the abuse of crack-cocaine, and these epidemics appear to target low income and minority groups. Public health issues relating to the physical, mental, and economic strain will be addressed, as well as the direct and indirect effects of the punishments that come as a result of the disparity in penalties for cocaine and crack-cocaine possession and distribution. ^ Three new policies have recently been introduced into the United Stated Congress that actively address the disparity in sentencing for drug and criminal activities. They are, (1) Powder-Crack Cocaine Penalty Equalization Act of 2009, (HR 18, 111th Cong. 2009), (2) The Drug Sentencing Reform and Cocaine Kingpin Trafficking Act of 2009, (HR 265, 111th Cong. 2009) and (3) The Justice Integrity Act of 2009, (111th Cong. 2009). ^ Although they have only been initiated, if passed, they have potential to not only eliminate the crack-cocaine disparity, but to enact laws that help those affected by this epidemic. The final and overarching goal of this paper is to analyze and ultimately choose the ideal policy that would not only eliminate the cocaine and crack disparity regardless of current or future state statutes, but will provide the best method of rehabilitation, prevention, and justice. ^

Results of bulk sediment X-ray diffraction analysis and quantification of mineral phases based on the RockJock and on the QUAX quantitative analysis

We have performed quantitative X-ray diffraction (qXRD) analysis of 157 grab or core-top samples from the western Nordic Seas between (WNS) ~57°-75°N and 5° to 45° W. The RockJock Vs6 analysis includes non-clay (20) and clay (10) mineral species in the <2 mm size fraction that sum to 100 weight %. The data matrix was reduced to 9 and 6 variables respectively by excluding minerals with low weight% and by grouping into larger groups, such as the alkali and plagioclase feldspars. Because of its potential dual origins calcite was placed outside of the sum. We initially hypothesized that a combination of regional bedrock outcrops and transport associated with drift-ice, meltwater plumes, and bottom currents would result in 6 clusters defined by "similar" mineral compositions. The hypothesis was tested by use of a fuzzy k-mean clustering algorithm and key minerals were identified by step-wise Discriminant Function Analysis. Key minerals in defining the clusters include quartz, pyroxene, muscovite, and amphibole. With 5 clusters, 87.5% of the observations are correctly classified. The geographic distributions of the five k-mean clusters compares reasonably well with the original hypothesis. The close spatial relationship between bedrock geology and discrete cluster membership stresses the importance of this variable at both the WNS-scale and at a more local scale in NE Greenland.