Showing papers by "Clemson University published in 1981"

A Positive Theory of Monetary Policy in a Natural-Rate Model

Abstract: Natural-rate models suggest that the systematic parts of monetary policy will not have important consequences for the business cycle. Nevertheless, we often observe high and variable rates of monetary growth, and a tendency for monetary authorities to pursue countercyclical policies. This behavior is shown to be consistent with a rational expectations equilibrium in a discretionary environment where the policymaker pursues a "reasonable" objective, but where precommitments on monetary growth are precluded. At each point in time, the policymaker optimizes subject to given inflationary expectations, which determine a Phillips Curve-type tradeoff between monetary growth/inflation and unemployment. Inflationary expectations are formed with the knowledge that policymakers will be in this situation. Accordingly, equilibrium excludes systematic deviations between actual and expected inflation, which means that the equilibrium unemployment rate ends up independent of "policy" in our model. However, the equilibrium rates of monetary growth/inflation depend on various parameters, including the slope of the Phillips Curve, the costs attached to unemployment versus inflation, and the level of the natural unemployment rate. The monetary authority determines an average inflation rate that is "excessive," and also tends to behave countercyclically. Outcomes are shown to improve if a costlessly operating rule is implemented in order to precomrnit future policy choices in the appropriate manner. The value of these precommitments -- that is, of long-term agreements between the government and the private sector -- underlies the argument for rules over discretion. Discretion is the sub-set of rules that provides no guarantees about the government's future behavior.

Viviparity: The Maternal-Fetal Relationship in Fishes

Abstract: SYNOPSIS. Viviparity in the vertebrate line first makes its evolutionary appearance among fishes. It has independently evolved in a number of divergent piscine lineages. The 54 families of extant fishes that bear living young include 40 families of chondrichthyans (sharks and rays), one montypic family of coelacanths ( Latimeria ), and 13 families of teleosts. There is fossil evidence for viviparity in holocephalans and chondrosteans. Viviparity predominates among sharks and rays (40 families, 99 genera, 420 species) but is less widespread among teleosts (13 families, 122 genera, 510 species). Following an historical introduction, the organization of the female reproductive system, sites of gestation, developmental sequences and superfetation are considered. The evolution of viviparity establishes specialized maternal-fetal relationships, viz. , 1) developmental, 2) morphological, 3) trophic, 4) osmoregulatory, 5) respiratory, 6) endocrinological, and 7) immunological. While the latter four categories are briefly noted the major emphasis is on the trophic relationship and its morphological and developmental basis. First, a general overview is presented and then the maternal-fetal trophic relationships in each of the major groups of fishes are systematically reviewed. Pertinent anatomical, histological, ultrastructural, developmental, physiological, and biochemical studies are considered. Viviparous fishes are either lecithotrophic, i.e. , exclusively yolk dependent, or matrotrophic, i.e. , in receipt of a continuous supply of maternal nutrients during gestation. Nutrient transfer is accomplished by 1) oophagy and adelphophagy, 2) placental analogues, and 3) the yolk sac placenta. Placental analogues include: external epithelial absorptive surfaces, e.g. , skin, fins, gills; trophonemata, modifications of the uterine epithelia for the secretion of histotrophe or “uterine milk”; branchial placentae, close apposition between gill epithelia and either uterine or ovarian epithelial villi; the yolk sac; pericardial amnion and chorion; follicular pseudoplacenta, close apposition between follicle cells and embryonic absorptive epithelia; hypertrophied gut; and trophotaeniae, external rosette or ribbon-like projections of the embryonic gut. Among chondrichthyans, the yolk sac placenta (840–1,050%), trophonematal secretion and embryonic absorbtion of histotrophe (1,680–4,900%) and oophagy and adelphophagy (1.2 × 106%) are the most efficient methods of nutrient transfer. Among teleosts, the follicular pseudoplacenta (1,800–3,900%), trophotaeniae (8,400%) and absorption of ovarian histotrophe through surface epithelia and a hypertrophied gut (1,100–34,000%) are the most efficient. These values stand in contrast to the 30%40% loss of dry weight characteristic of oviparous fishes and viviparous lecithotrophes.

Control of Calcium Carbonate Nucleation and Crystal Growth by Soluble Matrx of Oyster Shell

Abstract: A calcium-binding soluble protein extracted from oyster shell suppresses calcium carbonate nucleation and decreases the rate of crystal growth in vitro. These findings suggest that soluble matrix may regulate shell growth.

Positive dependence in multivariate distributions

Abstract: This paper gives some new results on positive dependence between random variables which are jointly normally distributed with special reference to certain inequalities of the form P‘X∊A,Y∊B’ > P‘X∊A’P‘Y∊ B’ , where A and B are given sets and X and Y are random vectors. Some results are also given on statistical dependence between quadratic forms

Piezoelectric ceramic implants: in vivo results

Abstract: The suitability of barium titanate (BaTiO3) ceramic for direct substitution of hard tissues was evaluated using both electrically stimulated (piezoelectric) and inactive (nonpolarized) test implants. Textured cylindrical specimens, half of them made piezoelectric by polarization in a high electric field, were implanted into the cortex of the midshaft region of the femora of dogs for various periods of time. Interfacial healing and bio-compatibility of the implant material were studied using mechanical, microradiographical, and histological techniques. Our results indicate that barium titanate ceramic shows a very high degree of biocompatibility as evidenced by the absence of inflammatory or foreign body reactions at the implant-tissue interface. Furthermore, the material and its surface porosity allowed a high degree of bone ingrowth as evidenced by microradiography and a high degree of interfacial tensile strength. No difference was found between the piezoelectric and the electrically neutral implant-tissue interfaces. Possible reasons for this are discussed. The excellent mechanical properties of barium titanate, its superior biocompatibility, and the ability of bone to form a strong mechanical interfacial bond with it, makes this material a new candidate for further tests for hard tissue replacement.

Overwintering Habitats, Spring Emergence Patterns, and Winter Mortality of Some South Carolina Hemiptera

Abstract: During a 3-year study, 522 overwintered individuals among 47 species of Pentatomidae, Scutelleridae, Corimelaenidae, Cydnidae, Coreidae, and Reduviidae emerged into cages placed over ground litter in 6 habitats. Among economically important pentatomids, Euschistus servus (Say) was most abundant and preferred open habitats, whereas E. tristigmus (Say) and Podisus maculiventris (Say) overwintered in deciduous woods and their borders. Acrosternum hilare (Say) preferred deciduous woods. Nezara viridula (L.) was found to overwinter primarily in above-ground habitats. Euthyrhynchus floridanus (L.) overwintered as eggs behind tree bark. No N. viridula survived the winter when caged over wild radish, deciduous leaf litter, or soybean stubble. Only 9% of the A. hilare caged over leaf litter survived during 1976 and 1977. Weather data suggest that absence of N. viridula in South Carolina during 1977 and 1978 was due to the two previous severe winters. Most overwintered A. hilare survivors emerged during early April; E. servus and E. tristigmus emerged from late March through April. Spring emergence was stimulated by increasing temperatures.

Courts of Appeals in the Federal Judicial System: A Study of the Second, Fifth, and District of Columbia Circuits

Abstract: Courts of Appeals were designed to be a unifying force in American law and politics, but they also contribute to decentralization and regionalization of federal law. Woodford Howard studies three aspects of this problem: first, what binds the highly decentralized federal courts into a judicial system; second, what controls the discretion of judges in making law and policy; and third, how can quality judicial decisions be maintained under heavy-volume pressure.Originally published in 1981.The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

Effects of varying chamber construction and embryo pre-incubation age on survival and growth of chick embryos in shell-less culture.

Abstract: Shell-less culture involves culturing chick embryos with associated yolk and albumen outside of the eggshell and shell membranes. The technique allows direct access to and continuous observation of cultured embryos almost to the time of hatching. The plastic wrap/culture tripod technique described in this paper allows normal embryonic growth and differentiation from 48 hours (in ovo pre-incubation age) through at least 10 days of total incubation. As the duration of in ovo pre-incubation is decreased below 36 hours, there is a concomitant increase in the percentage of grossly abnormal embryos associated with decreased survival and retarded growth and differentiation. Survival of embryos pre-incubated for 72 hours through 13 and 18 days of total incubation is greater than 80% and 40%, respectively. The wrap/tripod technique allows substantially better survival and more normal development of cultured embryos than does the petri dish technique of Auerbach et al. (1974). Embryonic growth in 7.8-cm-diameter chambers is significantly greater than in either larger (10.6 cm) or smaller (5.2 cm) diameter chambers. Some gas exchange through the culture chamber walls appears necessary for optimal embryonic survival and growth. Suspending egg contents in either Safeway or Handi-Wrap plastic wrap (both of intermediate permeability) in 7.8-cm tripods resulted in superior growth and/or survival compared to suspension in Silastic sheeting (high permeability), Saran Wrap (low permeability), glass dishes (nonpermeable), or glass dishes lined with an inner layer of Safeway wrap(nonpermeable).

Foraging Behavior of the Red-Cockaded Woodpecker in South Carolina

Abstract: Foraging Red-cockaded Woodpeckers (Picoides borealis) selected live pines (96% use; 71% availability) over hardwoods (1% use; 25% availability). Use of recently dead pines (3%) was the largest departure from use of live pines. Mast was rarely consumed, although abundant at times. Live pine stems greater than 23 cm in diameter at breast height represented only 19% of the available pines but received 65% of the use. The sexes exhibited strong divergence in foraging behavior. Most important was the partitioning of foraging sites on live pines. Males foraged on dead and live limbs of the crown and midtrunk 54% of the time and females only 4%. On the lower trunk, females foraged 38% of the time and males only 3%. On the midtrunk, females foraged 29% and males 12%. On the trunk-in-crown, females foraged 28% and males 32 %. Mean foraging height of males was 14.1 m and that of females 8.7 rn (P < 0.001). The sexes used tree sizes, tree types, and methods for capturing prey with similar frequencies. Within each sex, there were between-season differences in use of foraging sites and in methods used at each site. Received 9 July 1980, accepted 5 January 1981.

Effects of size and temperature on mud crab, Panopeus herbstii , predation on hard clams, Mercenaria mercenaria

Abstract: Predation byPanopeus herbstii onMercenaria mercenaria was significantly affected by temperature, and the size of predators and prey items. LargerP. herbstii opened more clams and preyed more successfully on larger clams than did smaller crabs. Increase in seed clam size and decrease in water temperature significantly reduced predation. Clam size appeared to be more important than crab satiation in reducing predation rate. Planting larger seed clams in cooler months should help to improve clam survival by reducing the impact ofP. herbstii in culture operations.

Tissue residues of dietary cadmium in wood ducks.

Abstract: One-week-old wood ducks were fed cadmium in diets containing 18 or 30% protein for a period of three months. Seven drakes from each group were sacrificed, and blood, brain, muscle, kidney, liver, and wing feather tissues were collected and analyzed for cadmium. Highest cadmium concentrations were found in the kidney, liver, and feather tissues; blood, muscle, and brain cadmium residue levels were undetectable. Except in the kidney tissue, protein level of the diet did not affect cadmium residue levels. For birds that were changed to a cadmium-free, high-protein ration at 13 weeks of age, regression analysis indicated a significant decrease in cadmium residue levels for the kidney tissue only. Growth, as measured by body weight at 13 weeks of age, was not affected by the various cadmium treatment levels. Histopathological examination revealed lesions in the kidney tissues of the 100 ppm cadmium treatment groups, which were more severe in those birds receiving the 18% protein diet. Vacuolation of the pancreatic acinar cells was observed in all groups, but tended to occur more frequently in the higher cadmium level groups.

Ermakov systems and quantum-mechanical superposition laws

Abstract: Ermakov systems are pairs of coupled, time-dependent, nonlinear dynamical equations possessing a joint constant of the motion called an Ermakov invariant. The invariant provides a link between the two equations and leads to a superposition law between solutions to the Ermakov pair. Extensive studies of Ermakov systems in classical mechanics have been carried out. Here we present a detailed study of Ermakov systems from a quantum point of view, and prove that the solution to the Schr\"odinger equation for a general Ermakov system can be reduced to the solution of a time-independent Schr\"odinger equation involving the Ermakov invariant. We thereby arrive at a quantum-mechanical superposition law analogous to the classical superposition law.

Requirements for food packaged in polymeric films

Abstract: The requirements of barrier properties of packaging materials against environmental factors vary with food products. The chemical, physical, and biological mechanisms of food deterioration due to environmental factors, vital properties required in packaging materials, and developments in progress and future trends to maintain the required standard of food quality have been critically reviewed. Theoretical and experimental results for a variety of food products in relation to the properties of the packaging materials are discussed. Methods of prediction of food stability and their industrial applications are also emphasized by specific examples.

Infra-red technique for cerebral blood flow: comparison with 133Xenon clearance.

Abstract: A rapid infra-red optical technique has been developed for the measurement of cerebral blood flow. The method measures optical density changes across the intact skull. during the passage of a bolus of the dye, Cardia-Green (CG). The clearance curves obtained for CG boluses are very short (< 30 sec) in comparison with those obtained with tracers such as 133Xenon (10-30 min) that distribute into cerebral tissue. The volume of distribution of CG is totally intravascular, and the dye is relatively slowly cleared from the body. The important advantages of this spectrophotometric technique are its speed, versatility, and the avoidance of radioactive materials. The differential spectrophotometer used in this study, with trivial modifications, has been used to monitor changes in brain blood volume, oxygen saturation of hemoglobin , and cortical mitochondrial respiratory function, which illustrate the versatility of the technique for neurological assessments.

On domination related concepts in Graph Theory

Abstract: A survey of recent results on domination and related concepts in graph theory is presented.

Heterotrophic Carbon Metabolism by Beggiatoa alba

Abstract: The assimilation and metabolism of CO2 and acetate by Beggiatoa alba strain B18LD was investigated. Although B. alba was shown to require CO2 for growth, the addition of excess CO2 (as NaHCO3) to the medium in a closed system did not stimulate growth. Approximately 24 to 31% of the methyl-labeled acetate and 38 to 46% of the carboxyl-labeled acetate were oxidized to 14CO2 by B. alba. The apparent Vmax values for combined assimilation and oxidation of [2-14C]acetate by B. alba were 126 to 202 nmol min−1 mg of protein−1 under differing growth conditions. The Vmax values for CO2 assimilation by heterotrophic and mixotrophic cells were 106 and 131 pmol min−1 mg of protein−1, respectively. The low Vmax values for CO2 assimilation, coupled with the high Vmax values for acetate oxidation, suggested that the required CO2 was endogenously produced from acetate. Moreover, exogenously supplied acetate was required by B. alba for the fixation of CO2. From 61 to 73% of the [14C]acetate assimilated by washed trichomes was incorporated into lipid. Fifty-five percent of the assimilated [2-14C]acetate was incorporated into poly-β-hydroxybutyric acid. This was consistent with chemical data showing that 56% of the heterotrophic cell dry weight was poly-β-hydroxybutyric acid. Succinate and CO2 were incorporated into cell wall material, proteins, lipids, nucleic acids, and amino and organic acids, but not into poly-β-hydroxybutyric acid. Glutamate and succinate were the major stable products after short-term [1-14C]acetate assimilation. Glutamate and aspartate were the first stable 14CO2 fixation products, whereas glutamate, a phosphorylated compound, succinate, and aspartate were the major stable 14CO2 fixation products over a 30-min period. The CO2 fixation enzymes isocitrate dehydrogenase (nicotinamide adenine dinucleotide phosphate; reversed) and malate dehydrogenase (nicotinamide adenine dinucleotide phosphate; decarboxylating) were found in cell-free extracts of both mixotrophically grown and heterotrophically grown cells. The data indicate that the typical autotrophic CO2 fixation mechanisms are absent from B. alba B18LD and that the CO2 and acetate metabolism pathways are probably linked.

Note-Prediction Intervals for Warranty Reserves and Cash Flows

Abstract: This paper presents estimates of cash flows associated with a given warranty policy. Included in the results are prediction intervals for warranty reserves and cash flows. A numerical example is given to illustrate these results.

Molecular and macroscopic properties of PMMA bone cement: free-radical generation and temperature change versus mixing ratio.

Abstract: The molecular and macroscopic changes occurring during the polymerization of poly(methyl methacrylate) (PMMA) bone cement have been investigated. Electron paramagnetic resonance (EPR) spectroscopy was used to monitor free-radical generation and this was compared to temperature changes occurring in the cement for various ratios of polymer powder to liquid monomer (P/L ratio) used in the sample preparation. Both the concentration and the characteristic growth time of the free radicals associated with the polymerization of the bone cement depended on the P/L ratio used. Larger P/L ratio resulted in shorter characteristic growth time for the free radicals as well as a shorter time for the occurrence of the peak sample temperature. Smaller P/L ratios gave smaller maximum concentrations of free radicals and larger peak temperatures. These results are explained on the basis of (1) more initiators present at higher P/L ratios resulting in faster polymerization and (2) less initiators and more monomers present at smaller P/L ratios resulting in fewer radicals but more exothermic reactions. The free radicals present in the bone cement due to the manufacturer's sterilization process were found to be proportional to the fraction of powder used in the preparation, indicating negligible monomer loss during sample mixing.

Chicken and Turkey Spermatozoal Superoxide Dismutase: A Comparative Study

Abstract: Superoxide dismutase (SOD) is one of several enzymes in aerobic cells which scavenge for toxic derivatives of oxygen. These derivatives cause lipid peroxidation, a type of cellular damage that may in part explain the loss of fertilizing capability of chicken and turkey spermatozoa stored in vitro. The objective of the present research was to extract SOD from chicken and turkey erythro- cytes and spermatozoa and to compare SOD activities between the two types of spermatozoa and between the spermatozoa and isogeneric erythrocytes, cells rich in SOD. Based upon activity of purified extracts, chicken spermatozoa contained 1.48 ± 0.08, while turkey spermatozoa contained 0.32 ± 0.01 activity units/109 cells. Chicken and turkey erythro- cytes had 2.65 ± 0.20 and 2.95 ± 0.39 units/109 cells, respectively. When SOD activity was ex- pressed as density, i.e., units/mm3 of cell volume, chicken spermatozoa had an activity density of 10.6 x 102 units/mm3, 4.6 times more than turkey spermatozoa, which had 2.3 X 102 units/ mm3. The activity density for erythrocytes from both species was “. 2.0 X 10 units/mm3. On the basis of cyanide inhibition, erythrocytes contained only cupro-zinc SOD, but spermatozoa con- tained both cupro-zinc and mangano superoxide dismutases. The lower SOD activity in turkey spermatozoa may result in a greater susceptibility to oxygen toxicity for turkey semen stored in Vitro.

Direct calculation of fluctuation formulae in the microcanonical ensemble

Abstract: We present simple derivations of the classical microcanonical ensemble formulae for fluctuations which involve the kinetic energy and microscopic pressure function. The new derivations, which confirm earlier results of Lebowitz et al. [1] and Cheung [2], proceed in a direct way from basic microcanonical ensemble theory without recourse to fluctuation expressions of other ensemble theories. The method developed is applicable to shell ensembles in general.