Quantifying the Inefficiency of the US Social Security System

We quantify the inefficiency of the retirement component of the US social security system within a model where agents receive idiosyncratic labor-productivity shocks that are privately observedsocial security, efficient allocations, idiosyncratic shocks

Scanning Electron Microscope and X-Ray Diffraction Investigations of Mudrock Fabrics, Textures and Mineralogy

Mudstones from a broad range of depositional environments have been investigated to determine whether fabric, texture or mineralogy may (1) be used to identify the environment of deposition and (2) be correlated with poroperm. The diversity of fabrics and textures reflects features of the detrital mudstone composition, compaction and diagenesis, rather than environment of deposition. Preferred orientation has been disturbed by bioturbation and growth of post-compactional authigenic minerals; these factors have reduced to nil any correlation which may have existed between fabric, measured as the illite orientation ratio (O/R) and environment of deposition. It is mineralogy rather than fabric or texture which, after compaction, have most influenced the poroperm. Preliminary results suggest that abundant illite/illite-smectite results in higher poroperm than abundant detrital kaolinite

The Effect Of Tropical Storm Agnes On Heavy Metal And Pesticide Residues In The Eastern Oyster From Southern Chesapeake Bay

The concentrations of cadmium, copper, and zinc in the eastern oyster, Crassostrea virginica, are compared for samples collected before and after Tropical Storm Agnes. The before samples consisted of 475 animals from 95 stations collected in January 1971 and the after samples of 285 animals from 57 stations collected in January 1973. Shifts in the areal concentrations distributions were observed, apparently due to Agnes. Analyses of hard clams, blue crabs and oysters for chlorinated hydrocarbon pesticides showed influx of these compounds to be minimal as reflected by the residue levels observed. Comparison of residue levels in oysters to pre-Agnes conditions revealed a decrease in pesticide body burden.https://scholarworks.wm.edu/vimsbooks/1069/thumbnail.jp

Methods for measuring ecosystem stress

If one looks back over the past twenty-five years, at the pollution crises which have made the headlines and influenced our decision making policies on both local and national levels, one may note a very interesting aspect. That is, the crises are often associated with the development of new and more sensitive types of analytical instrumentation. Several examples of this readily come to mind: for example, it wasn\u27t until the development of electron capture detection for gas chromatography that DDT really became a crisis. The reason is quite simple: the concentrations which were being accumulated by the organisms were below detection limits of most available instrumentation. Another example is mercury. The advent of atomic absorption spectrophotometry and the refinement of the the flameless method for mercury allowed the mercury problem to be investigated. New instrumentation doesn\u27t cause the crisis, it merely finds it.https://scholarworks.wm.edu/vimsbooks/1135/thumbnail.jp

Long Term Culture of Hepatocytes of Some Fish Species of the Chesapeake Bay

The liver is an important site of metabolism and effects of toxic chemicals. This makes it an important organ for tumorigenesis studies. This study was aimed at investigating the optimal culture characteristics of liver cells derived from some indigenous Chesapeake Bay fish species. Hepatocytes from Atlantic -menhaden (Brevootia tyraMus), toadfish (Opsanus tau), croaker (Micropogonius undulatus), and hogchocker (Trinectes maculatus) were isolated using an enzymatic dispersion technique. The highest yield was obtained from toadfish livers (14.9±5. lx 1 o5 cells/g oflive weight) and the lowest was from the croaker (5.9±3. lx 1 o5 cells/g of live body weight). The percentage of hepatocytes in cell preparations exceeded 90% except for the toadfish liver cells preparation (82.3%). Freshly isolated hepatocytes were globular with irregular contour and occurred as individual cells or small clusters of 2-30 cells. A confluent monolayer of attached cells was obtained after two weeks of incubation. An osmolality of 325 m Osm/kg best supported the multiplication of hepatocytes of the four fish species. While the optimum temperature for hogchocker and toadfish hepatocytes appeared to be 33oC; it ranged from 21-27oC for menhaden and croaker. The medium that best supported the growth of culture The potential of long term hepatocyte culture using fish of Chesapeake Bay will enable further studies on the activation and detoxification processes of xenobiotics and, therefore, help in understanding pollution related neoplasia and diseaseshttps://scholarworks.wm.edu/vimsbooks/1181/thumbnail.jp

Misuse of prescription only medication and over-the-counter-medication among drug users

This report presents the results of a study that investigated the misuse and diversion of prescription-only-medication and over-the-counter-medication (POM/OTC) among people who use illegal drugs. The study was conducted by a team of researchers from the University of South Wales in collaboration with Dr Rhian Hills from the Substance Misuse Policy Branch within the Welsh Government. The research was undertaken across Wales and was based on qualitative interviews with a sample of people who had lived experience of prescription drug misuse, and also included an online questionnaire survey completed by professionals working within the field of substance misuse. The main aim of the study was to identify the causes, patterns and consequences of POM/OTC misuse and diversion among people with a history of illegal drug use. For the purpose of this document in relation to POM/OTC use, we have used the term nonmedical prescription drug use and its associated acronym (NMPDU) to refer to the misuse of prescription-only medication. Definitions of key terms are presented below and followed by information about the prevalence of NMPDU among both the general and drug-using population. This is then followed by a brief overview of the potential harms that are associated with this behaviour and the responses that are often used to try to counteract it. The study ends with brief chapter summaries to provide readers with an overview of the report structure and content

Dynamic Performance of a Wind Turbine Based on a Self-Excited Induction Generator

The paper is devoted to the study of the dynamic performance of a wind turbine in a remote site microgrid based on a self-excited induction generator (SEIG) during sudden load connection. A dynamic model of the currents of the SEIG in the stationary reference frame dq axis is introduced and the main effect of saturation flux in the SEIG is explained. The case of self-excitation with different capacities and connected with purely resistive and inductive loads are discussed in this paper. Keywords: Renewable Energy, Induction Generator, Islanded Wind, Modeling, Self-Excited Induction Generato

Distribution of copper and zinc in oysters and sediments from three coastal-plain estuaries.

Copper and zinc were analyzed in oysters (Crassostrea virginica) from the Newport River estuary, North Carolina, and the Rappahannock River estuary, Virginia. Results indicated that a concentration gradient existed, higher concentrations of metals being found in animals living in fresher waters as was shown previously for oysters in the James, York, and Rappahannock estuaries in Virginia. Absorbed, precipitatcd-coprecipitated, and organic fractions of copper and zinc in the \u3c63-μm portion of the sediments from the Rappahannock and York rivers and estuaries were estimated from collections made in January 1972 and June 1973. These sediment data are discussed for both estuarine systems and are compared with metal concentrations in oysters. These comparisons indicated that the concentration gradient found in oysters does not appear to be related to the distribution of copper and zinc in the sediments. Alternative explanations for the inverse relationships between concentrations of copper and zinc in oysters and salinity arc given.https://scholarworks.wm.edu/vimsbooks/1146/thumbnail.jp