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Showing papers by "University of Delaware published in 1988"


Book
01 Jan 1988
TL;DR: In this paper, the authors discuss diversity, necessity, and evolution, and conclude that evolution and progress are the most important factors in the evolution of a society. But they do not discuss the role of economic and military factors.
Abstract: Preface 1. Diversity, necessity, and evolution 2. Continuity and discontinuity 3. Novelty: psychological and intellectual factors 4. Novelty: socioeconomic and cultural factors 5. Selection: economic and military factors 6. Selection: social and cultural factors 7. Conclusion: evolution and progress Bibliography Sources of questions Index.

1,050 citations


Journal ArticleDOI
TL;DR: The crisis management of disasters does not follow automatically from disaster planning as discussed by the authors, and there are management problems with respect to the communication process, the exercise of authority, and the development of co-ordination.
Abstract: The crisis management of disasters does not follow automatically from disaster planning. Research has shown that successful disaster management results primarily from the activities of emergency organizations. In particular, there are management problems with respect to the communication process, the exercise of authority, and the development of co-ordination. There are at least five different areas of difficulties in the communication process, namely, intra- and inter-organizational behaviours between organizations, from organizations to the public, from the public to organizations, and within systems of organizations. Exercise of authority difficulties stem from losses of higher echelon personnel because of over-work, conflict regarding authority over new disaster tasks, and clashes over organizational jurisdictional differences. Co-ordination difficulties come from lack of consensus among organizations, working on common but new disaster-related tasks, and difficulties in achieving overall co-ordination in any community disaster that is of any magnitude. Prior planning can limit these management difficulties but cannot completely eliminate all of them.

636 citations


Journal ArticleDOI
TL;DR: In this paper, seasonal variability in stable carbon (S’XZ) and nitrogen (b15N) isotope ratios was observed in suspended particulate matter of the Delaware estuary.
Abstract: ,Qbstract Seasonal variability in stable carbon (S’XZ) and nitrogen (b15N) isotope ratios was observed in suspended particulate matter of the Delaware estuary. Two major pools of organic matter were found in the estuary-phytoplankton growing in situ and a mixture of planktonic and terrestrial detritus. In general, the 6°C and 615N of suspended particulate matter reflected planktonic dominance. With the background chemical and physical information available for the estuary, it is evident that biogeochemical processes influence isotopic distributions in the estuary to a greater extent than does physical mixing. During spring, we postulate that isotopic fractionation of ammonium assimilated at concentrations >20 PM resulted in more negative 615N values for organic matter fixed by phytoplankton. As algal growth proceeded, the 615N of seston reached a maximum (+ 1 SY&) because phytoplankton were using a pool of NH,+ enriched in 15N as a result of previous fractionation during assimilation. Similarly, maximal 813C values were related to high rates of primary productivity associated with algal growth. Decreased isotopic fractionation occurred at high rates of production, implying that diffusion of CO, across the cell membrane became increasingly rate limiting. The 613C values in bottom sediments were equivalent to those in suspended particulate matter, but a 2Y60 difference in 615N was found between suspended and bottom sediments. With nitrogen isotopic differences between water-column seston and surficial sediments, we estimate that 1530% of planktonic production is deposited in the sediments during spring. If this organic matter is remineralized in late summer and fall, it could support up to 20% of primary production at that time.

488 citations


Journal ArticleDOI
TL;DR: In this paper, the authors deal with the solution of the stress, displacement, and pore pressure field induced by the drilling and/or the pressurization of a vertical borehole.

413 citations


Journal ArticleDOI
TL;DR: In this article, the authors developed and validated an instrument that could be used to ascertain motives individuals have for interpersonal communication, including six prominent motives: pleasure, affection, inclusion, escape, relaxation, and control.
Abstract: The goal of this study was to develop and validate an instrument that could be used to ascertain motives individuals have for interpersonal communication. A 28-item scale is presented along with initial information about the scale’s construct validity. Results indicated there were six prominent motives: pleasure, affection, inclusion, escape, relaxation, and control. Low communicative apprehensives used interpersonal communication for pleasure, affection, and control while high apprehensiues were more aligned with the inclusion motive. The motives of pleasure, affection; and relaxation were more closely related to communication satisfaction. In fact, communication satisfaction was best predicted by low communication apprehension, gender, and the pleasure, affection, relaxation, and escape communication motives.

343 citations


Journal ArticleDOI
TL;DR: It is argued that the feature of conditionallogit makes it more appropriate for estimating behavioral models, rather than the other way around, than the more familiar multinomial logit model.
Abstract: Although discrete-choice statistical techniques have been used with increasing regularity in demographic analyses, Mcl’adden’s conditional logit model is less well known and seldom used. Conditional logit models are appropriate when the choice among alternatives is modeled as a function of the characteristics of the alternatives, rather than (or in addition to) the characteristics of the individual making the choice. We argue that this feature of conditionallogit makes it more appropriate for estimating behavioral models. In this article, the conditional logit model is presented and compared with the more familiar multinomial logit model. The difference between the two techniques is illustrated with an analysis of the choice of marital and welfare status by divorced or separated women.

253 citations



Journal ArticleDOI
TL;DR: Although the need for appropriate conversion factors has not been eliminated, the dual-label approach can be used to examine the variation in bacterial production while ensuring that the observed variation in incorporation rates is due to real changes inacterial production rather than changes in conversion factors or introduction of other artifacts.
Abstract: We examined the simultaneous incorporation of [H]thymidine and [C]leucine to obtain two independent indices of bacterial production (DNA and protein syntheses) in a single incubation. Incorporation rates of leucine estimated by the dual-label method were generally higher than those obtained by the single-label method, but the differences were small (dual/single = 1.1 +/- 0.2 [mean +/- standard deviation]) and were probably due to the presence of labeled leucyl-tRNA in the cold trichloroacetic acid-insoluble fraction. There were no significant differences in thymidine incorporation between dual- and single-label incubations (dual/ single = 1.03 +/- 0.13). Addition of the two substrates in relatively large amounts (25 nM) did not apparently increase bacterial activity during short incubations (<5 h). With the dual-label method we found that thymidine and leucine incorporation rates covaried over depth profiles of the Chesapeake Bay. Estimates of bacterial production based on thymidine and leucine differed by less than 25%. Although the need for appropriate conversion factors has not been eliminated, the dual-label approach can be used to examine the variation in bacterial production while ensuring that the observed variation in incorporation rates is due to real changes in bacterial production rather than changes in conversion factors or introduction of other artifacts.

210 citations


Journal ArticleDOI
TL;DR: Probleme de la determination de la celerite du son dans un milieu heterogene connaissant les champs diffuses lointains is discussed in this article.
Abstract: Probleme de la determination de la celerite du son dans un milieu heterogene connaissant les champs diffuses lointains

191 citations


Journal ArticleDOI
TL;DR: In this article, the authors consider methods for solving the transmission problem using a single integral equation over S for a single unknown function, and derive four different integral equations, using a hybrid of the direct (Green's theorem) and indirect (layer ansatz) methods, and give conditions for the unique-solvability of each and for the subsequent construction of the solution.
Abstract: The transmission problem, namely scattering of time-harmonic waves in a compressible fluid by a fluid inclusion with different material properties, is usually formulated as a pair of coupled boundary integral equations over the interface S between the inclusion and the exterior fluid. In this paper, however,we consider methods for solving the transmission problem using a single integral equation over S for a single unknown function. In fact, we derive four different integral equations, using a hybrid of the direct (Green’s theorem) and indirect (layer ansatz) methods, and give conditions for the unique-solvability of each and for the subsequent construction of the solution to the transmission problem. Some of our single integral equations are Fredholm integral equations of the second kind with weakly-singular kernels. Thus, these equations, all of which appear to be new, are attractive computationally.

176 citations


Journal ArticleDOI
TL;DR: Soit Ω⊂R n un domaine borne as mentioned in this paper, on considere □u+q≡u tt −Δ x u+q(x)u=0 dans Ω×[O, T], u(x, o)=Φ(x),u t (x, O)=Ψ(x).
Abstract: Soit Ω⊂R n un domaine borne. On considere □u+q≡u tt −Δ x u+q(x)u=0 dans Ω×[O, T], u(x, o)=Φ(x),u t (x, o)=Ψ(x) si x∈Ω, ∂u(x, t)/∂n=f(x, t) sur ∂Ω×[O, T]. Pour q(x) fixe c'est un probleme aux valeurs limites et initiales bien pose. On demontre l'unicite pour le probleme inverse

Journal ArticleDOI
TL;DR: This analysis suggests that Weitzman’s finding concerning the precipitous decline in the economic status of women following divorce is likely to be incorrect and her findings not only imply improbably large changes in income but are also inconsistent with the information she reports on changes in Income and in income per capita.
Abstract: Our analysis suggests that Weitzman’s finding concerning the precipitous decline in the economic status of women following divorce is likely to be incorrect. Her findings not only imply improbably large changes in income but are also inconsistent with the information she reports on changes in income and in income per capita. Corrected estimates suggest a decline in economic status of about one-third, rather than the widely cited 73 percent figure.

Journal ArticleDOI
TL;DR: It is proposed that the LC is tuned to specifically respond to stimuli which are conspicuous to that species: stimuli which by their physical or behavioral properties evoke a change in the focus of attention.

Journal ArticleDOI
TL;DR: The solution to the problem of maximizing total utility of consumption is given by way of quasi-variational inequalities for the value function of risky assets and one nonrisky asset with log-normal prices.
Abstract: An investor has the opportunity of holding shares in n risky assets and one nonrisky asset at every time in a fixed interval [t, T]. The risky assets are governed by a stochastic differential equation. At random instants of his choice he may intervene in order to rebalance his portfolio and consume a nonnegative amount of money. Fixed and variable transactions costs are incurred upon intervention. At time T all remaining wealth is consumed. The solution to the problem of maximizing total utility of consumption is given by way of quasi-variational inequalities for the value function. With probability one the investor only intervenes finitely many times. Indication of the solution of the quasi-variational inequalities in the case of one risky asset with log-normal prices is given, together with a description of a discretization procedure.

Journal ArticleDOI
TL;DR: This paper used American (Manchester, New Hampshire) and Japanese (Shizuoka) cohorts in 1910-1950 to explore the similarities and differences between "life-course transitions, " defined as the move.
Abstract: This study uses American (Manchester, New Hampshire) and Japanese (Shizuoka) cohorts in 1910-1950 to explore the similarities and differences between "life-course transitions, " defined as the move

Journal ArticleDOI
TL;DR: In this article, the corrosion potential of AISI 316 stainless steel and the oxygen reduction rate, as measured by the cathodic polarization curve, have been determined with and without the formation...
Abstract: The corrosion potential of AISI 316 stainless steel (SS) and the oxygen reduction rate, as measured by the cathodic polarization curve, have been determined with and without the formation ...

Journal ArticleDOI
TL;DR: In this article, the dry wear behavior of several polymer composite materials sliding against smooth steel counterparts was investigated and the contribution from the post-sliding wear mechanisms are not directly measurable and were estimated by employing the wear model.

Journal ArticleDOI
TL;DR: In this paper, a new concept for measuring fiber-matrix interaction in a single filament, or a single uniaxially reinforced thin layer, sandwiched between two relatively thick unreinforced layers is proposed.
Abstract: This paper reviews various common methods for studying fiber-matrix interaction with specific evaluation of the critical fiber length method. Commonly accepted methods are often shown to be unsatisfactory because interfacial results may not be independent of fiber tensile strength properties. A new concept for measuring fiber-matrix interaction in a single filament, or in a single uniaxially reinforced thin layer, sandwiched between two relatively thick unreinforced layers is proposed. This method relies upon variable curvature bending jigs introducing continuously changing longitudinal shear profiles across the fiber surface by clamping the sandwiched specimen onto the jig surface and also upon the availability of physical detection methods of debonding fronts.

Journal ArticleDOI
TL;DR: The surface-bound metal carbonyls react on metal oxide surfaces to give a wide range of structures analogous to those of known compounds as discussed by the authors, including formation of acid-base adducts as the oxygen of a carbonyl group donates an electron pair to a Lewis acidic center, nucleophilic attack at CO ligands by basic surface hydroxyl groups or O2⊖ ions.
Abstract: Metal carbonyls react on metal oxide surfaces to give a wide range of structures analogous to those of known compounds. The reactions leading to formation of surface-bound metal carbonyls are explained by known molecular organometallic chemistry and the functional group chemistry of the surfaces. The reaction classes include formation of acid-base adducts as the oxygen of a carbonyl group donates an electron pair to a Lewis acidic center; nucleophilic attack at CO ligands by basic surface hydroxyl groups or O2⊖ ions; ion-pair formation by deprotonation of hydrido carbonyls to give carbonylate ions; interaction of bifunctional complexes with surface acid-base pair sites such as [Mg2⊕O2⊖]; and oxidative addition of surface hydroxyl groups to metal clusters. The reactions of surface-bound organometallic species include redox condensation and cluster formation on basic surfaces (paralleling the reactions in basic solution) as well as oxidation of mononuclear metal complexes and oxidative fragmentation of metal clusters by reaction with surface hydroxyl groups. Most supported metal carbonyls are unstable at high temperatures, but some, including osmium carbonyl cluster anions on the basic MgO surface, are strongly stabilized in the presence of CO and are precursors of catalysts for CO hydrogenation at 550 K.

Proceedings ArticleDOI
22 Aug 1988
TL;DR: The resulting system, Feature Structure based Tree Adjoining Grammars (FTAG), captures the principle of factoring dependencies and recursion, fundamental to TAG's, and it is shown that FTAG has an enhanced descriptive capacity compared to TAG formalism.
Abstract: We have embedded Tree Adjoining Grammars (TAG) in a feature structure based unification system. The resulting system, Feature Structure based Tree Adjoining Grammars (FTAG), captures the principle of factoring dependencies and recursion, fundamental to TAG's. We show that FTAG has an enhanced descriptive capacity compared to TAG formalism. We consider some restricted versions of this system and some possible linguistic stipulations that can be made. We briefly describe a calculus to represent the structures used by this system, extending on the work of Rounds, and Kasper [Rounds et al. 1986, Kasper et al. 1986] involving the logical formulation of feature structures.

Journal ArticleDOI
TL;DR: In this paper, the authors found that when given a nominally sodium-free diet for 10-13 days, rats were less sensitive to salt and acid stimuli and more sensitive to sugar.
Abstract: 1. Maintenance of sodium balance is crucial to mammals and is expressed in the innate salt appetite. With depletion, sodium preference is exaggerated, hypertonic solutions accepted and salt balance restored. This compensatory behaviour is thought to result from a centrally induced change in taste responsiveness. This proposal was tested by recording taste activity from ninety-four single neurones in the nucleus tractus solitarius of sodium-replete (N = 44) and of deprived (N = 50) rats. Twelve Wistar rats were given a nominally sodium-free diet for 10-13 days, and the resulting sodium depletion confirmed by flame photometry of their urine. Nine rats provided control data. Taste stimuli included five concentrations of NaCl (0.003-0.3 M) plus eight other salts, acids, sugars and alkaloids. 2. Taste responsiveness was generally reduced in sodium-depleted rats. Spontaneous activity was 33% lower while responses to sodium salts lagged by a mean of 30%, to acids by 25% and to bitter salts and quinine by 17%. Mean activity to sugars was 60% higher in the deprived group. 3. Activity in sugar- and salt-profile neurones was most affected. In deprived animals responses to sodium salts were lower by 80% among salt-profile cells while among sugar-profile neurones activity to these stimuli was nearly 10 times greater than in controls. These changes in activity resulted in a dramatic shift in the participation of sodium- and sugar-profile cells in the afferent signal for NaCl. In replete animals 60% of sodium-induced activity was transmitted through salt-profile cells while only 1% occurred in sugar-profile neurones. In deprived subjects this situation was nearly reversed as 7% of the total NaCl response was conveyed through salt-profile cells while the contribution of neurones with sugar-profiles rose to 46%. 4. Multidimensional stimulus spaces based on average activity in each of four identifiable neurone subgroups demonstrated a shift in the affiliation of sodium salts away from bitter and acid stimuli and towards sugars. 5. These results confirm earlier findings from the chorda tympani that sodium deprivation suppresses activity evoked by sodium salts. However the application of more recent analytical procedures permits quite a different interpretation of this finding. The overall decrease is merely the net effect of a shift in the major responsibility for encoding sodium from salt-profile neurones to those whose primary sensitivity is to sugars.(ABSTRACT TRUNCATED AT 400 WORDS)

Journal ArticleDOI
TL;DR: Understanding the origin and role of growth-induced water potentials helps to explain how cell enlargement is inhibited without a decrease in turgor when water is depleted in the soil or more rapidly lost by transpiration.
Abstract: Understanding the origin and role of growth-induced water potentials helps to explain how cell enlargement is inhibited without a decrease in turgor when water is depleted in the soil or more rapidly lost by transpiration. In many cases, changes in growth-induced water potentials probably cause the inhibition initially, but eventually the cell walls lose extensibility and specific proteins accumulate so that metabolic changes in the walls probably limit later growth.

Journal ArticleDOI
15 Jan 1988-Wear
TL;DR: In this paper, the effect of fiber orientation on the dry abrasivedominant wear behavior of continuous-carbon-fiber-reinforced polyetheretherketone (CF-PK) and continuous-aramid fiber reinforced epoxy (K49/3501-6) was investigated.

Journal ArticleDOI
01 Sep 1988
TL;DR: On caracterise des suites kn de telle facon que l'estimateur de Hill de l'indice de queue base sur les kn statistiques d'ordre superieures d'un echantillon de taille n d'une distribution de Type Pareto soit fortement consistant as mentioned in this paper.
Abstract: On caracterise des suites kn de telle facon que l'estimateur de Hill de l'indice de queue base sur les kn statistiques d'ordre superieures d'un echantillon de taille n d'une distribution de Type Pareto soit fortement consistant

Journal Article
TL;DR: This paper describes the IREPS system, emphasizing its dynamic construction of the task-related plan motivating the information-seeker's queries and the application of this component of a user model to handling utterances that violate the pragmatic rules of the system's world model.
Abstract: This work is an ongoing research effort aimed both at developing techniques for inferring and constructing a user model from an information-seeking dialog and at identifying strategies for applying this model to enhance robust communication. One of the most important components of a user model is a representation of the system's beliefs about the underlying task-related plan motivating an information-seeker's queries. These beliefs can be used to interpret subsequent utterances and produce useful responses. This paper describes the IREPS system, emphasizing its dynamic construction of the task-related plan motivating the information-seeker's queries and the application of this component of a user model to handling utterances that violate the pragmatic rules of the system's world model. By reasoning on a model of the user's plans and goals, the system often can deduce the intended meaning of faulty utterances and allow the dialogue to continue without interruption. Some limitations of current plan inference systems are discussed. It is suggested that the problem of detecting and recovering from discrepancies between the system's model of the user's plan and the actual plan under construction by the user requires an enriched model that differentiates among its components on the basis of the support the system accords each component as a correct and intended part of the user's plan.

Journal ArticleDOI
TL;DR: In this article, the results of methanol, ethanol, 1-propanol, and 2-Propanol were examined on a Pd(111) surface containing one-quarter monolayer of adsorbed oxygen atoms.

Journal ArticleDOI
TL;DR: In this paper, an extensive pore water data set has been gathered in the Great Marsh, Delaware over various seasons, salinities, and tides, and the data all point to a complimentary redox cycle for sulfur and iron which operates seasonally and tidally.

Journal ArticleDOI
TL;DR: The ability to adjust body size as density fluctuates may allow Diadema to persist when density increases, by shrinking and reducing metabolic costs, and to take advantage of decreases in density, by increasing in size and fecundity.
Abstract: This study documents size- and density-dependent growth (positive and negative), in the sea urchin Diadema antillarum. In the summer of 1983, an inverse relationship was found between Diadema test diameter and population density at seven sites in Lameshur Bay, St. John, United States Virgin Islands. The regression of this relationship improved when test diameter was plotted against density per unit grazing area. A field experiment demonstrated that 1) Diadema has the ability to reduce skeletal body size, and 2) direction (growth or shrinkage) and rate of growth can be predicted accurately based on the urchin's body size and population density. The ability to adjust body size as density fluctuates may allow Diadema to persist when density increases, by shrinking and reducing metabolic costs, and to take advantage of decreases in density, by increasing in size and fecundity.

Journal ArticleDOI
Jin Wu1
TL;DR: In this paper, the fractional coverage of the sea surface was shown to follow a power law, W = 2U3.7510, where U10 is the wind velocity at 10 m above the mean sea surface.
Abstract: Results of whitecap coverages from five previously reported oceanic experiments by Monahan and coinvestigators have been analyzed; the fractional coverage of the sea surface(W) was shown to follow a power law, W = 2U3.7510, where U10 is the wind velocity at 10 m above the mean sea surface. Attempts were then made to associate the coverage with the wind-friction velocity (u*) deduced from the wind velocity and air–sea temperature differences as W = 0.2u3*. Finally, we discuss effects of the water temperature on the coverage.

Journal ArticleDOI
TL;DR: The biogeographic and climatic barrier across the Australia Papua New Guinea land bridge has remained largely intact in spite of a range of environmental conditions that have occured during the last century as mentioned in this paper.