Showing papers by "University of South Carolina published in 1978"

The Randomized Play-the-Winner Rule in Medical Trials

Abstract: In a sequential medical trial, a simple randomized treatment assignment rule is proposed and analyzed. On the average this rule assigns more patients to the better treatment, and it is applicable to the case where patients have delayed responses to treatments. This new assignment rule is studied for both a fixed sample size and an inverse stopping rule.

An Application of an Urn Model to the Design of Sequential Controlled Clinical Trials

Abstract: In the comparison of K treatments, assume that patients appear singly and must be treated immediately. Suppose that patients having the same combination of prognostic factor levels are grouped into the same stratum. If the number of different strata is small, we treat each stratum as a separate independent subtrial. A treatment assignment rule is proposed that forces a small subtrial to be balanced, but tends toward the complete randomization scheme as the size of the subtrial increases. When the number of strata is large, we propose an overall assignment rule which can achieve a degree of treatment balance simultaneously across all prognostic factors.

Field evidence that shrimp predation regulates meiofauna.

Abstract: The grass shrimp Palaemonetes pugio, a suspected predator/disturber on meiofauna, and other large natant forms (>2 mm) were selectively excluded from microecosystem tanks for nine months during which time replicability between the tanks was established. Subsequently, shrimp were reintroduced into one of the four tanks via an aquarium and the meiofauna populations monitored in the “shrimp” and control tanks. In the presence of the predator/disturber, total meiofauna, nematode, oligochaete, and polychaete densities were significantly lower than in control tanks. In the presence of the predator/disturber, total meiofauna, nematode, oligochaete, and polychaete densities were significantly lower than in control tanks. Shrimp predation/disturbance significantly reduced meiofauna abundance in this salt marsh habitat but it did not alter the species diversity of the dominant taxon. The meiobenthos displayed characteristics common to other biologically regulated assemblages and our data provide the first field evidence of macrofaunal control of meiofauna community structure.

Some approximate tests for repeated measurement designs

Abstract: Four approximate tests are considered for repeated measurement designs in which observations are multivariate normal with arbitrary covariance matrices. In these tests traditional within-subject mean square ratios are compared with critical values derived fromF distributions with adjusted degrees of freedom. Two of them—the ∈ approximate and the improved general approximate (IGA) tests—behave adequately in terms of Type I error. Generally, the IGA test functions better than the ∈ approximate test, however the latter involves less computations. In regards to power, the IGA test may compete with one multivariate procedure when the assumptions of the latter are tenable.

Periodic Freshwater Flooding and Stagnation of the Eastern Mediterranean Sea During the Late Quaternary

Abstract: Major negative oxygen isotopic anomalies in planktonic foraminifera are associated with deep-sea anoxic mud layers (sapropels) deposited 9000 and 80,000 years ago in the eastern Mediterranean. The isotopic depletion in surface-dwelling foraminifera is significantly greater than in mesopelagic foraminifera. This difference in isotopic response suggests that surface-water salinities were drastically reduced during times of sapropel formation, possibly as the result of meltwater runoff from the Fennoscandian ice sheet into the eastern Mediterranean by way of the Black and Aegean seas.

Drug Abuse Patterns, Personality Characteristics, and Relationships with Sex, Race, and Sensation Seeking.

Abstract: Department of Psychiatry and Behavioral SciencesMedical University of South CarolinaInterrelationships among sex, race, drug use patterns, and personality variableswere examined in a sample of 84 chronic users of illicit drugs. Subjects wereadministered the Minnesota Multiphasic Personality Inventory, the SensationSeeking Scale, and the Shipley Institute of Living Scale and were interviewedusing the Background Information Questionnaire. Comparisons were made be-tween sex and ethnic subgroups on personality and drug use variables usinganalysis of covariance and chi-square procedures for subjects classified intohigh-, medium-, and low-sensation-seeking groups. Blacks were characterized bylower levels of sensation seeking, less psychopathology, use of fewer drug cat-egories, and later drug use than whites. Use and personality patterns amongwomen differed little from those of men. Levels of sensation seeking were re-lated to specific personality constellations, number of drug categories used, andmotive for first alcohol use.Research on the psychological character-istics of drug abusers h'as developed fromattempts to describe and differentiate addictsfrom representatives of other clinically de-viant categories. More recently, investigatorshave compared drug abuse subgroups (de-fined by race and sex) on personality dimen-sions or drug use patterns. Female and whitedrug abusers have been shown to demonstrategreater psychopathology than males and non-whites (DeLeon, 1974; Olson, 1964), andethnicity was found to be related to choiceof drug type and variety used, particularlyamong men (K'aestner, Rosen, & Appel,1977). Suffet and Brotman (1976) reported

Microstructure of Agglomerated Suspended Sediments in Northern Chesapeake Bay Estuary

Abstract: Suspended sediments in the turbidity maximum of Chesapeake Bay include composite particles which contain platy mineral grains, arranged both in pellets (attributable to fecal pelletization) and in networks of angular configuration (attributable to electrochemical flocculation and coagulation).

The Channeled Scabland

Abstract: The geomorphology and hydrodynamics of high velocity flood erosion in the channeled scabland of the Columbia Basin are discussed.

Low-frequency response of estuarine sea level to non-local forcing

Abstract: Variability in estuarine sea level and net flow on time scales longer than the predominant tidal cycle have long been ignored. However, recent work by Elliott (1976) focuses on the transient nature of estuarine circulation and its relation to local and far-field forcing with periods from 2 to 20 days. This forcing is well correlated with atmosphere variability, primarily wind events. North Inlet, South Carolina, is an ideal estuary for studies of non-local forcing because of the near absence of freshwater discharge and the small size of the winding estuarine creeks. One-year time series records of sea level, atmospheric pressure, and wind speed and direction indicate two important sea level responses. A 3.2 cm high 6.0-day sea level wave is attributable to atmospheric pressure, and a 6.4 cm high sea level fluctuation varies with the alongshore wind stress with a period of 9.2 days. In each case, it is believed that the forcing is transferred to the estuary from the coastal ocean via continental shelf waves. In addition, the yearly cycle of mean sea level, which is primarily due to changes in ocean and estuarine water temperature, causes the surrounding marshes to flood to a greater extent in the fall. This may be an important factor in facilitating material exchanges between estuary and marshes and could also be responsible for controlling net fluxes in or out of the estuary.

When the Cartesian Product of Directed Cycles is Hamiltonian

Abstract: The cartesian product of two hamiltonian graphs is always hamiltonian . For directed graphs, the analogous statement is false . We show that the cartesian product C, x C„ 2of directed cycles is hamiltonian if and only if the greatest common divisor (g.c.d.)d ofn, and n2is at least two and there exist positive integers d,, d2so thatd, + d2= d and g.c.d.(n,,d,) = g.c.d. (n2, d2)= 1. We also discuss some number-theoretic problems motivated by this result .

Albumin Storage Proteins in the Protein Bodies of Castor Bean

Abstract: Of the total protein in the protein bodies of castor bean (Ricinus communis L.), approximately 40% is represented by a group of closely related albumins localized in the matrix of the organelle. This group of albumins has a sedimentation value of 2S and is resolved into several proteins of molecular weight around 12,000 daltons by sodium dodecyl sulfate-acrylamide gel electrophoresis. It has a high content of glutamate/glutamine and undergoes rapid degradation during the early stage of germination. In view of the abundance and ubiquitous occurrence of albumins in various seeds, we suggest that albumins, in addition to globulins, glutelins, and prolamines, are important storage proteins in seeds.

Lipases in the storage tissues of peanut and other oil seeds during germination.

Abstract: The castor-bean endosperm-the best-studied material of reserve lipid hydrolysis in seed germination-was previously shown to have an acid lipase and an alkaline lipase having reciprocal patterns of development during germination. We studied oil seeds from 7 species, namely castor bean (Ricinus communis L.), peanut (Arachis hypogaea L.), sunflower (Helianthus annus L.), cucumber (Cucumis sativus L.), cotton (Gossypisum hirsutum L.), corn (Zea mays. L.) and tomato (Lycopersicon esculentum Mill.). The storage tissues of all these oil seeds except castor bean contained only alkaline lipase activity which increased drastically during germination. The pattern of acid and alkaline lipases in castor bean does not seem to be common in other oil seeds. The alkaline lipase of peanut cotyledons was chosen for further study. On sucrose gradient centrifugation of cotyledon homogenate from 3-d-old seedlings, about 60% of the activity of the enzyme was found to be associated with the glyoxysomes, 15% with the mitochondria, and 25% with a membrane fraction at a density of 1.12 g cm-3. The glyoxysomal lipase was associated with the organelle membrane, and hydrolyzed only monoglyceride whereas the mitochondrial and membrane-fraction enzymes degraded mono-, di- and triglycerides equally well. Thus, although the lipase in the glyoxysomes had the highest activity, it had to cooperate with lipases in other cellular compartments for the complete hydrolysis of reserve triglycerides.

Application of an Oil Spill Vulnerability Index to the Shoreline of Lower Cook Inlet, Alaska

Abstract: Offshore tracts in Alaska's lower Cook Inlet are scheduled to be opened for exploratory petroleum drilling in the near future. Because of the potential for oil spills resulting from this activity, a field study of the coastal zone was conducted in June 1976. A total of 1216 km of shoreline was classified into 3 types: erosional (45 percent), neutral (38 percent), and depositional (17 percent). These were further subdivided into 16 subclasses on the basis of small scale morphological features. This classification was used in conjunction with a vulnerability index of potential oil spill damage, developed through study of three major oil spills, to predict the longevity of oil in the different coastal environments of the Inlet. On a scale from 1 to 10, 45 percent of the shoreline has low values of 1 to 4, which means that oil would be dispersed by natural processes within less than six months after a spill on these coasts. Values from 4 to 6 were assigned to 13.4 percent of the shoreline, where oil residence time may be up to one year. A 6 to 10 rating was assigned to 41.5 percent of the shoreline, where oil contamination may remain for periods of two to ten years, or possibly longer should no major clean-up procedures be initiated. We propose that the use of this type of vulnerability indexing, in conjunction with a biological susceptibility index and oil spill trajectory models, would provide a rational basis for decision making concerning the location of on- and off-shore oil facilities and the design of oil spill contingency plans.

The Relationship Among Teaching Methods, Student Characteristics, and Student Involvement in Learning

Abstract: Various classroom teaching methods have been termed &dquo;lesson formats&dquo; (Dunkin & Biddle, 1974) or, more simply, &dquo;teaching methods&dquo; (Berliner & Gage, 1976). The latter define teaching methods as &dquo;recurrent instructional processes, applicable to various subject matters, and usable by more than one teacher&dquo; (p. 5). Three commonly used teaching methods are lecture, discussion, and seatwork. Although teachers use a variety of these methods in their classes, they have received little help from theorists or researchers as to which method, or methods, best facilitates learning. Early research, mostly conducted at the postsecondary level, compared the effectiveness of any two teaching methods. Dubin and Taveggia (1968)’ reviewed 36 experimental studies on the most popular comparison between lecture and discussion methods. They found that 51 percent of the comparisons favored the lecture method, and 49 percent favored the discussion method. Virtually no overall difference in the effectiveness of the two methods was indicated.

Late Pliocene climate and south-west Atlantic abyssal circulation

Abstract: THE late Pliocene is characterised by a global climatic cooling1–4 and by widespread erosion of abyssal sediments by Antarctic Bottom Water (AABW)5–6. The global cooling is dated between 2.5 and 3.0 Myr based on the age of the oldest tillite in Iceland7, the initiation of glaciation in the Sierra Nevada of the USA8, faunal changes in Antarctic and sub-Antarctic deep-sea cores9–11, and a change in carbonate preservation in the equatorial Pacific12. This cooling may be synchronous with the development of the Northern Hemisphere ice sheet which has been dated by the first appearance of ice-rafted debris in the North Atlantic at 3 Myr followed by a major influx at 2.6 Myr (ref. 13), and by a large change in the oxygen isotope record of benthic foraminifera indicating an increase in ice volume at ∼ 2.6 Myr (refs 2, 3). The global cooling and deep-sea erosion events have been identified in widely separated studies and the ages assigned to each are based on biostratigraphic zonations with long durations. The apparent synchroneity of the two events (within the limits of the methods used) has led to the suggestion of a cause and effect relationship with the global cooling driving the increase in abyssal circulation14, 15. In an attempt to find the cause of the relative timing of both the climatic and circulation events, which has not been determined with sufficient stratigraphic resolution, we have examined two late Pliocene sections in the south-west Atlantic.

Genetic regulation of liver alcohol dehydrogenase in Peromyscus

Abstract: Data from genetic crosses of Peromyscus maniculatus and P. polionotus suggest that electrophoretic variants of liver alcohol dehydrogenase are coded by alleles at a single locus. These alleles, designated Adh F , Adh S , and Adh N , determine, respectively, the fast, slow, and not detectable (null) ADH electrophoretic phenotypes. Heterozygotes (Adh F /Adh S ) exhibit three bands on zymograms, suggesting a dimeric subunit structure for the enzyme. However, Adh F /Adh N and Adh S /Adh N animals exhibit a single band, suggesting that the Adh N allele does not produce a polypeptide subunit capable of dimerizing into an active molecule. Fast and slow electrophoretic phenotypes exhibit multiple bands which can be converted into single major fast and slow bands, respectively, upon treatment with oxidized or reduced NAD. Addition of NAD also stabilizes both the fast and slow enzyme to heat inactivation at 60 C for at least 30 min.