Showing papers by "Iowa State University published in 1993"
TL;DR: A description of the ab initio quantum chemistry package GAMESS, which can be treated with wave functions ranging from the simplest closed‐shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication.
Abstract: A description of the ab initio quantum chemistry package GAMESS is presented. Chemical systems containing atoms through radon can be treated with wave functions ranging from the simplest closed-shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication. Emphasis is given to novel features of the program. The parallelization strategy used in the RHF, ROHF, UHF, and GVB sections of the program is described, and detailed speecup results are given. Parallel calculations can be run on ordinary workstations as well as dedicated parallel machines. © John Wiley & Sons, Inc.
18,546 citations
TL;DR: The chapter discusses two important directions of research to improve learning algorithms: the dynamic node generation, which is used by the cascade correlation algorithm; and designing learning algorithms where the choice of parameters is not an issue.
Abstract: Publisher Summary This chapter provides an account of different neural network architectures for pattern recognition. A neural network consists of several simple processing elements called neurons. Each neuron is connected to some other neurons and possibly to the input nodes. Neural networks provide a simple computing paradigm to perform complex recognition tasks in real time. The chapter categorizes neural networks into three types: single-layer networks, multilayer feedforward networks, and feedback networks. It discusses the gradient descent and the relaxation method as the two underlying mathematical themes for deriving learning algorithms. A lot of research activity is centered on learning algorithms because of their fundamental importance in neural networks. The chapter discusses two important directions of research to improve learning algorithms: the dynamic node generation, which is used by the cascade correlation algorithm; and designing learning algorithms where the choice of parameters is not an issue. It closes with the discussion of performance and implementation issues.
13,033 citations
TL;DR: Sum rules are derived for the circular dichroic response of a core line (CMXD) that relate the intensity of the CMXD signal to the ground-state expectation value of the magnetic field operators (orbital, spin, and magnetic dipole) of the valence electrons.
Abstract: Sum rules are derived for the circular dichroic response of a core line (CMXD). They relate the intensity of the CMXD signal to the ground-state expectation value of the magnetic field operators (orbital, spin, and magnetic dipole) of the valence electrons. The results obtained are discussed and tested for transition metals and rare earths.
1,828 citations
TL;DR: In this paper, the authors examine conceptual and operational issues associated with the perceived-minus-expectations (P-E) perceived service quality model and conclude that the P-E framework is...
Abstract: The author examines conceptual and operational issues associated with the “perceptions-minus-expectations” (P-E) perceived service quality model. The examination indicates that the P-E framework is...
1,767 citations
TL;DR: In this article, the authors developed statistical methods for using degradation measures to estimate a time-to-failure distribution for a broad class of degradation models, using a nonlinear mixed-effects model and developing methods based on Monte Carlo simulation to obtain point estimates and confidence intervals for reliability assessment.
Abstract: Some life tests result in few or no failures. In such cases, it is difficult to assess reliability with traditional life tests that record only time to failure. For some devices, it is possible to obtain degradation measurements over time, and these measurements may contain useful information about product reliability. Even with little or no censoring, there may be important practical advantages to analyzing degradation data. If failure is defined in terms of a specified level of degradation, a degradation model defines a particular time-to-failure distribution. Generally it is not possible to obtain a closed-form expression for this distribution. The purpose of this work is to develop statistical methods for using degradation measures to estimate a time-to-failure distribution for a broad class of degradation models. We use a nonlinear mixed-effects model and develop methods based on Monte Carlo simulation to obtain point estimates and confidence intervals for reliability assessment.
1,062 citations
TL;DR: In this paper, the authors review the detailed understanding of asymptotic kinetics, spatial correlations, percolative structure, etc., which is emerging for these far-from-equilibrium processes.
Abstract: Irreversible random sequential adsorption (RSA) on lattices, and continuum "car parking" analogues, have long received attention as models for reactions on polymer chains, chemisorption on single-crystal surfaces, adsorption in colloidal systems, and solid state transformations. Cooperative generalizations of these models (CSA) are sometimes more appropriate, and can exhibit richer kinetics and spatial structure, e.g., autocatalysis and clustering. The distribution of filled or transformed sites in RSA and CSA is not described by an equilibrium Gibbs measure. This is the case even for the saturation "jammed" state of models where the lattice or space cannot fill completely. However exact analysis is often possible in one dimension, and a variety of powerful analytic methods have been developed for higher dimensional models. Here we review the detailed understanding of asymptotic kinetics, spatial correlations, percolative structure, etc., which is emerging for these far-from-equilibrium processes.
898 citations
TL;DR: This work describes a procedure that consistently permits isolation of cotton genomic DNA of satisfactory size and quality for RFLP and PCR analysis, as well as for most routine cloning applications.
Abstract: Extraction of high-quality genomic DNA fromGossypium (cotton) species is difficult due to high levels of polysaccharide, oxidizable quinones, and other interfering substances. We describe a procedure that consistently permits isolation of cotton genomic DNA of satisfactory size and quality for RFLP and PCR analysis, as well as for most routine cloning applications. Several antioxidants, phenol-binding reagents, and phenol oxidase inhibitors are used throughout the procedure, and most polysaccharides are eliminated early in the procedure by isolation of nuclei.
776 citations
Book•
01 Jan 1993
722 citations
TL;DR: In this article, the authors analyzed the time series properties of various attack modes used by transnational terrorists and evaluated the effectiveness of six policies designed to thwart terrorism, finding strong evidence of both substitutes and complements among the attack modes.
Abstract: Using quarterly data from 1968 to 1988, we analyze the time series properties of the various attack modes used by transnational terrorists. Combining vector autoregression and intervention analysis, we find strong evidence of both substitutes and complements among the attack modes. We also evaluate the effectiveness of six policies designed to thwart terrorism. The existence of complements and substitutes means that policies designed to reduce one type of attack may affect other attack modes. For example, the installation of metal detectors in airports reduced skyjackings and diplomatic incidents but increased other kinds of hostage attacks (barricade missions, kidnappings) and assassinations. In the long run, embassy fortification decreased barricade missions but increased assassinations. The Reagan “get tough” policy, which resulted in the enactment of two laws in 1984 and a retaliatory raid on Libya in 1986, did not have any noticeable long-term effect on curbing terrorist attacks directed against U.S. interests.
584 citations
TL;DR: It is demonstrated that distinct and long-lasting modulation in synaptic efficiency can be induced at primary afferent synapses with neurons in the superficial laminae of spinal dorsal horn by high-frequency stimulation of dorsal root afferents and that these changes may be physiologically relevant for transmission and integration of sensory information, including pain.
Abstract: Synaptic transmission between dorsal root afferents and neurons in the superficial laminae of the spinal dorsal horn (laminae I-III) was examined by intracellular recording in a transverse slice preparation of rat spinal cord. Brief high-frequency electrical stimulation (300 pulses at 100 Hz) of primary afferent fibers produced a long-term potentiation (LTP) or a long-term depression (LTD) of fast (monosynaptic and polysynaptic) EPSPs in a high proportion of dorsal horn neurons. Both the AMPA and the NMDA receptor-mediated components of synaptic transmission at the primary afferent synapses with neurons in the dorsal horn can exhibit LTP and LTD of the synaptic responses. In normal and neonatally capsaicin-treated rats, the induction of LTP requires the activation of NMDA receptor-gated conductances. The induction of LTP or LTD, however, was not abolished in the presence of bicuculline, a GABAA receptor antagonist. The results demonstrate that distinct and long-lasting modulation in synaptic efficiency can be induced at primary afferent synapses with neurons in the superficial laminae of spinal dorsal horn by high-frequency stimulation of dorsal root afferents and that these changes may be physiologically relevant for transmission and integration of sensory information, including pain.
548 citations
TL;DR: This paper examined the effects of formal strategic planning on small firm financial performance for more than twenty years, and drew differing conclusions about the effect of formal planning on the performance of small firms.
Abstract: Researchers have been examining the effects of formal strategic planning on small firm financial performance for more than twenty years. Reviewers of prior studies have drawn differing conclusions ...
TL;DR: In this paper, a family process model was proposed that links economic stress in family life to prosocial and problematic adolescent adjustment, and a sample of 220 7th-grade girls living in intact families in the rural Midwest were measured using both trained observer and family member reports.
Abstract: A family process model is proposed that links economic stress in family life to prosocial and problematic adolescent adjustment. With a sample of 220 7th-grade girls living in intact families in the rural Midwest, the theoretical constructs in the model were measured using both trained observer and family member reports. In general, results were consistent with the proposed model. Economic pressures led to depression and demoralization for both parents, the result of which was greater marital conflict and disruptions in skillful parenting. The emotions and behaviors of both mothers and fathers were almost equally affected by financial difficulties, and disruptions in eac parent's child-rearing behaviors had adverse consequences for adolescent development. Parents' depressed mood and disrupted child-rearing practices both directly affected girls' adjustment
TL;DR: Random amplified polymorphic DNA (RAPD) analysis appears to offer a cost- and time-effective alternative to restriction fragment-length polymorphism (RFLP) analysis, but concerns about the ability to compare RAPD results from one laboratory to another have not been addressed effectively.
Abstract: Random amplified polymorphic DNA (RAPD) analysis appears to offer a cost- and time-effective alternative to restriction fragment-length polymorphism (RFLP) analysis. However, concerns about the ability to compare RAPD results from one laboratory to another have not been addressed effectively. DNA fragments that were amplified by five primers and shown to be reproducibly polymorphic between two oat cultivars (within the Ottawa laboratory) were tested in six other laboratories in North America. Four of the six participants amplified very few or no fragments using the Ottawa protocol. These same participants were able to generate a considerable number of amplified fragments by using their own protocols. The reproducibility of results among laboratories was affected by two factors. First, different laboratories amplified different size ranges of DNA fragments, and, consequently, small and large polymorphic fragments were not always reproduced. Second, although reproducible results were obtained with four of the primers, reproducible results were not obtained with the fifth primer, using the same reaction conditions. It is suggested that if the overall temperature profiles (especially the annealing temperature) inside the tubes are identical among the laboratories, then RAPD fragments are likely to be reproducible.
TL;DR: It is proved using a combinatorial argument that any k-resilient protocol for the k-set agreement problem would satisfy the uncertainty condition, while this is not true for any (k−1)-resilients in a totally asynchronous system.
Abstract: We define the k-SET CONSENSUS PROBLEM as an extension of the CONSENSUS problem, where each processor decides on a single value such that the set of decided values in any run is of size at most k. We require the agreement condition that all values decided upon are initial values of some processor. We show that the problem has a simple (k−1)-resilient protocol in a totally asynchronous system. In an attempt to come up with a matching lower bound on the number of failures, we study the uncertainty condition, which requires that there must be some initial configuration from which all possible input values can be decided. We prove using a combinatorial argument that any k-resilient protocol for the k-set agreement problem would satisfy the uncertainty condition, while this is not true for any (k−1)-resilient protocol. This result seems to strengthen the conjecture that there is no k-resilient protocol for this problem. We prove this result for a restricted class of protocols. Our motivation for studying this problem is to test whether the number of choices allowed to the processors is related to the number of faults. We hope that this will provide intuition towards achieving better bounds for more practical problems that arise in distributed computing, e.g., the renaming problem. The larger goal is to characterize the boundary between possibility and impossibility in asynchronous systems given multiple faults.
TL;DR: In this article, it was shown that hysteresis in the magnetostriction k is coupled to the hystresis of the magnetization M due to the dependence of the magnetic properties on the magnetisation.
Abstract: It is demonstrated that hysteresis in the magnetostriction k is coupled to hysteresis in the magnetization M because of the dependence of the magnetostriction on the magnetization. At the same time, when stress is present, the magnetization is in turn coupled to the behavior of the part of the magnetostriction associated with domain moment rotation. An expression for the magnetostriction is formulated, and numerical modeling results for magnetostriction hysteresis are compared to experimental results. Although some features of the magnetostriction in iron and steel still need additional explanation, the main features of the magnetostriction are accounted for. These include liftoff (failure of the magnetostriction to return to its value in the demagnetized state as the hysteresis loop is cycled) and a magnetostriction increase after flux density B reaches its maximum and starts to decrease. A macromagnetic, multidomain formulation that yields zero magnetostriction in the demagnetized specimen is used. >
TL;DR: Laser ablation of metals is a new and very powerful method for preparation of surface-enhanced Raman scattering (SERS) active colloids as mentioned in this paper, which is characterized by its simplicity and versatility.
Abstract: Laser ablation of metals is a new and very powerful method for preparation of surface-enhanced Raman scattering (SERS) active colloids. The method is characterized by its simplicity and versatility. Stable Ag, Au, Pt, Pd, and Cu colloids are prepared by ablation of the metal for ~ 10 min in water and organic solvents. An important advantage of this approach over conventional chemical procedures is that the colloids are free of organic or ionic species. Consequently, the chemical and physical effects of ions or other adsorbates can be studied under carefully controlled conditions. The SERS activity of colloidal metals prepared by laser ablation is comparable or superior to that of chemically prepared colloids.
TL;DR: In this paper, the authors examined the authenticity of craft souvenirs from midwestern US tourists and found that tourists' definitions of authenticity varied with tourists' ages, stage of travel careers, and tourism styles.
TL;DR: In this article, the authors examine the degree to which the consumer expectations component of perceived service quality measurement frameworks (Parasuraman, Zeithaml, and Berry, 1988; Brown and Swartz, 1989; Carman, 1990) is characterized by discriminant validity with respect to other expectations concepts used in marketing.
Abstract: The purpose of this study is to examine questions concerning the degree to which the consumer expectations component of perceived service quality measurement frameworks (Parasuraman, Zeithaml, and Berry, 1988; Brown and Swartz, 1989; Carman, 1990) is characterized by discriminant validity with respect to other expectations concepts used in marketing. The findings provide preliminary evidence that the service quality expectations concept may have serious discriminant validity shortcomings which. in turn, cause the "perceptions-minus-expectations" service quality measurement framework to be a potentially misleading indicator of customer perceptions of service quality. Based upon these findings, potential solutions to the discriminant validity problems are explored.
TL;DR: In the past seven years, many examples of periodic crystals closely related to quasicrystalline alloys have been discovered, and these crystals have been termed approximants, since the arrangements of atoms within their unit cells closely approximate the local atomic structures in quasicalrystals.
Abstract: Over the past seven years, many examples of periodic crystals closely related to quasicrystalline alloys have been discovered. These crystals have been termed approximants, since the arrangements of atoms within their unit cells closely approximate the local atomic structures in quasicrystals. This colloquium focuses on these approximant structures, their description, and their relationship to quasicrystals.
University of Texas at Austin1, Cornell University2, Stanford University3, University of Illinois at Urbana–Champaign4, Brookhaven National Laboratory5, Tohoku University6, University of California, Berkeley7, IBM8, University of North Carolina at Chapel Hill9, Iowa State University10, Texas A&M University11, University of Utah12
TL;DR: In this article, the state of the art and potential future directions in the study of the electrode/electrolyte interface are discussed, and new approaches to studies of interfacial dynamics and materials aspects of the interface are also discussed.
Abstract: This is a report of a workshop on the [open quotes]state of the art[close quotes] and potential future directions in the study of the electrode/electrolyte interface. Recent advances in experimental capabilities of characterizing the structure of the interface, e.g., through the use of such techniques as scanning tunneling microscopy and X-ray methods, are described. New approaches to studies of interfacial dynamics and materials aspects of the electrode/electrolyte interface are also discussed. 346 refs., 17 figs.
TL;DR: In this article, a 3D network of trigonally connected tetrahedra decorated with a P=O unit is proposed for low-alkali phosphate glasses, and a structural transition from a 3-dimensional network of interconnected PO4 groups for P2O5 to a 1-dimensional chain structure for LiPO3 is shown.
Abstract: Anhydrous glasses in the series xLi2O + (1 - x)P2O5 have been prepared and characterized in the range 0 ≤x≤ 0.5. FT-IR spectroscopy and glass transition temperature measurements have been used to explore the structure and a key physical property of the low-alkali phosphate glasses. The structure of v-P2O5 is proposed to consist of a 3-D network of trigonally connected tetrahedra decorated with a P=O unit. Contrary to what has long been proposed for these glasses, the addition of alkali degrades the 3-D network through the generation of nonbridging oxygens rather than strengthen the network through the proposed alkali ion bridging. The Tg of v-P2O5 is ∼653 K and decreases some 130 K with the addition of 10 mol% Li2O. Tg then reaches a minimum value at 20 mol% Li2O and increases with further Li2O additions. The increase in Tg, even though the fraction of nonbridging oxygens is still increasing, is interpreted in terms of an increasing entanglement of long-chain PO2 groups in the glass. Such a structural transition from a 3-D network of interconnected PO4 groups for P2O5 to a 1-D chain structure for LiPO3 is one of the first examples of the importance of intermediate-range order in governing the properties of glass.
TL;DR: The results demonstrated that men are more likely than women to report exposure to and to be distressed by work and financial events, and women are more strongly influenced by exposure to negative events within the family but not within their network of friends.
Abstract: In the present study of 451 married couples living in the rural midwest, gender differences were examined in reports of exposure and vulnerability to specific types of undesirable life events. Consistent with expectations derived from either a social structural or identity perspective, the results demonstrated that men are more likely than women to report exposure to and to be distressed by work and financial events. Women, on the other hand, are more strongly influenced by exposure to negative events within the family but not within their network of friends. Outcomes vary according to the type of emotional distress. Financial stress, for example, increases hostility among men more than among women, but wives are more likely than husbands to report somatic complaints in response to the same stressor. The findings demonstrate the need for future research that more directly investigates the intraindividual and social mechanisms which account for gender differences in a broad range of emotional and behavioral responses to varying types of significant life changes.
TL;DR: Quantitative trait loci were mapped in segregating progeny from a cross between two soybean cultivars: ‘Minsoy’ and ‘Noir 1’ to discuss heritability and genetic correlation of the traits.
Abstract: Quantitative trait loci (QTL) were mapped in segregating progeny from a cross between two soybean (Glycine max (L.) Merr.) cultivars: ‘Minsoy’ (PI 27.890) and ‘Noir 1’ (PI 290.136). The 15 traits analyzed included reproductive, morphological, and seed traits, seed yield and carbon isotope discrimination ratios (13C/12C). Genetic variation was detected for all of the traits, and transgressive segregation was a common phenomenon. One hundred and thirty-two linked genetic markers and 24 additional unlinked markers were used to locate QTL by interval mapping and one-way analysis of variance, respectively. Quantitative trait loci controlling 11 of the 15 traits studied were localized to intervals in 6 linkage groups. Quantitative trait loci for developmental and morphological traits (R1, R5, R8, plant height, canopy height, leaf area, etc.) tended to be clustered in three intervals, two of which were also associated with seed yield. Quantitative trait loci for seed oil were separated from all the other QTL. Major QTL for maturity and plant height were linked to RFLP markers R79 (31% variation) and G173 (53% variation). Quantitative trait loci associated with unlinked markers included possible loci for seed protein and weight. Linkage between QTL is discussed in relation to the heritability and genetic correlation of the traits.
TL;DR: Investigations of the structural, vibrational, and electronic properties of the theoretical model provide fresh insights into the microscopic structure of diamondlike amorphous carbon films produced in ion-beam deposition experiments.
Abstract: An amorphous carbon network generated by quenching high-density high-temperature liquid carbon using tight-binding molecular-dynamics simulation is found to contain a large fraction of tetrahedral bonding sites. Investigations of the structural, vibrational, and electronic properties of the theoretical model provide fresh insights into the microscopic structure of diamondlike amorphous carbon films produced in ion-beam deposition experiments.
TL;DR: In this paper, the authors focused upon the relationship of intercultural communication competence with the amount of stress and the effectiveness of handling that stress as reported by international students attending a university in the Midwest United States.
TL;DR: Simultaneous measurements of gold with tobacco mosaic virus show that, at the same applied vertical force, the Tobacco mosaic virus is undamaged by blunt tips but is compressed or disintegrated under sharper scanning styli, suggesting that specimen degradation is partly a pressure-dependent effect.
TL;DR: The paucity of infected propriospinal neurons in the presence of infected brainstem neurons, even in lightly infected rats, is discussed in reference to the relative importance of descending vs spinal regulation of the sympathetic outflow to the kidney.
TL;DR: In this article, structural equation modeling was used with a sample of 451 2-parent families to test an elaboration of J. Belsky's (1984) model of the determinants of parental behavior.
Abstract: Structural equation modeling was used with a sample of 451 2-parent families to test an elaboration of J. Belsky's (1984) model of the determinants of parental behavior. Results largely supported the model. Economic pressure disrupted parenting by increasing depression and undermining access to spouse support. Spouse support had both a direct effect on parenting and an indirect influence through depression. For mothers, spouse support moderated the impact of economic strain on parenting by reducing the disruptive impact of depression parental behavior. Social network support only influenced parenting indirectly through depression. There was no support for the idea that social network support serves to buffer parental behavior against the adverse consequences of economic strain, nor was there evidence that it can compensate for low spouse support
TL;DR: The authors examines the political consequences that arise due to multiple and simultaneous bases of social experience, such as neighborhoods and churches, and examines the consequences of these bases of experience on political outcomes.
Abstract: This paper examines the political consequences that arise due to multiple and simultaneous bases of social experience. Two alternative contexts--those of neighborhoods and churches--provide an empi...