Preferential Arrangements Research Articles

Auditory corticocortical interconnections in the cat: evidence for parallel and hierarchical arrangement of the auditory cortical areas

The origin and laminar arrangement of the homolateral and callosal projections to the anterior (AAF), primary (AI), posterior (PAF) and secondary (AII) auditory cortical areas were studied in the cat by means of electrophysiological recording and WGA-HRP tracing techniques. The transcallosal projections to AAF, AI, PAF and AII were principally homotypic since the major source of input was their corresponding area in the contralateral cortex. Heterotypic transcallosal projections to AAF and AI were seen, originating from the contralateral AI and AAF, respectively. PAF received heterotypic commissural projections from the opposite ventroposterior auditory cortical field (VPAF). Heterotypic callosal inputs to AII were rare, originating from AAF and AI. The neurons of origin of the transcallosal connections were located mainly in layers II and III (70-92%), and less frequently in deep layers (V and VI, 8-30%). Single unit recordings provided evidence that both homotypic and heterotypic transcallosal projections connect corresponding frequency regions of the two hemispheres. The regional distribution of the anterogradely labeled terminals indicated that the homotypic and heterotypic auditory transcallosal projections are reciprocal. The present data suggest that the transcallosal auditory interconnections are segregated in 3 major parallel components (AAF-AI, PAF-VPAF and AII), maintaining a segregation between parallel functional channels already established for the thalamocortical auditory interconnections. For the intrahemispheric connections, the analysis of the retrograde tracing data revealed that AAF and AI receive projections from the homolateral cortical areas PAF, VPAF and AII, whose neurons of origin were located mainly in their deep (V and VI) cortical layers. The reciprocal interconnections between the homolateral AAF and AI did not show a preferential laminar arrangement since the neurons of origin were distributed almost evenly in both superficial (II and III) and deep (V and VI) cortical layers. On the contrary, PAF received inputs from the homolateral cortical fields AAF, AI, AII and VPAF, originating predominantly from their superficial (II and III) layers. The homolateral projections reaching AII originated mainly from the superficial layers of AAF and AI, but from the deep layers of VPAF and PAF. The laminar distribution of anterogradely labeled terminal fields, when they were dense enough for a confident identification, was systematically related to the laminar arrangement of neurons of origin of the reciprocal projection: a projection originating from deep layers was associated with a reciprocal projection terminating mainly in layer IV, whereas a projection originating from superficial layers was associated with a reciprocal projection terminating predominantly outside layer IV.(ABSTRACT TRUNCATED AT 400 WORDS)

Chains in Power Sets

When studying ordered sets a natural question that arises is: How many chains are there in a typical finite, partially ordered set? Generic questions about partially ordered sets (posets) have a long history and this particular question about the number of chains in a partially ordered set has connections to questions dealing with ordered partitions and trees that may be traced back to work by Cayley [3] in 1859. Our main goal in this article is to develop recursive and closed formulas for the total number of chains and the number of chains of a particular length in the power set of an n-element set, partially ordered by set inclusion. We also discuss a canonical relationship between these chains and the preferential arrangements of an n-element set discussed in [7] and [9]. Another objective is to use this question about chains to make two pedagogical points. First, frequently in mathematics there may be several approaches to solving a problem with each approach illuminating a different aspect of the problem. Chain counting provides such an occasion for illustrating a wide variety of techniques from classical combinatorics and, as a consequence, we sketch more than one line of attack for most of our results. Second, most of the results in this article are subsumed in more advanced and modern treatments of combinatorics. (Explicit reference to the literature is contained in our concluding remarks.) However, the classical combinatorial techniques used here are elementary and accessible to those familiar with counting techniques, generating functions, distribution and occupancy problems, Stirling numbers, and elementary differential equations. In particular, the generating function techniques exploit the remarkable correspondence, discovered by Laplace, between set theoretic operations and operations on formal power series. A comprehensive discussion of these classical techniques may be found in most advanced undergraduate texts on combinatorics (e.g., [11, Chapters 2, 3, 5, and 6]). Before we begin, a word of caution is in order. As in elementary number theory, questions about partially ordered sets may be easy to pose but quite difficult to resolve. Indeed, a simply stated open question [12, p. 103], closely related to the one we discuss here, is: What is the number of antichains in the power set of an n-element set? (An antichain is a subset of a poset in which no two elements are comparable.) We start by fixing some notation. Identifying an arbitrary n-element set in the natural way with Xn = (1, 2, .. ., n}, we partially order the power set 9Y(X,T) by set inclusion. If C: No C N1 C ... C Nk is a chain in A(Xn), we say C has length k. In particular, chains consisting of a single element of 32(Xn) have length 0. Furthermore, an k and an will denote, respectively, the number of chains of length k and the

Multiple Criteria Decision Making in Industry

I. Multiple Criteria Decision Making - An Introduction. MCDM - balancing a variety of needs and goals. Definition of MCDM. Conflicting criteria. Definitions: attributes, objectives, goals, criteria. II. Fundamentals of Multicriterion Optimization. Formulation. Concept of optimal and efficient solutions. Concept of ideal solutions. III. Importance of Criteria. Introduction. Scales of measurement. Concept of weights. Assessing the multiple criteria. Ranking. Rating. Paired comparison. Successive comparisons. Delphi technique. Concept of tradeoffs. IV. Techniques. Single objective approach. Unifying objective functions approach. Global criterion method. Utility function method. Minimum deviation method. Compromise constraint method. Bicriterion linear programming. The case of multiple objective functions. Goal programming approach. Formulation. GP versus LP. Simplex method of goal programming. Some complications and their resolutions. Interactive approach. Step method. ``Game Theoretic'' technique. Interactive sequential conversion of objectives into constraints (ISOC). Compromise programming. Electre approach. Electre I. Electre II. Parametric approach. De Novo programming. Theoretical foundations. Formulation. Special characteristics. Effects of multiple pricing. Increasing cost of raw materials. Quantity discounts. Decreasing revenues. De Novo's applicability in MODM. V. MCDM Applications in Production Management. Introduction. Aggregate production planning. Generalized model. Other models. Multistage production planning and scheduling. Introduction. Model formulation. Production planning: the case of a cement plant. Production planning: short versus long term. Machine sequencing with forbidden early shipments. Quality control model: designing a sampling plan. Batch production planning. Resource and product mix problem: case study. Production situation. Unlimited demand situation. Limited demand situation. Multiobjective decision models. Global criterion method. Compromise constraint method. The step method (STEM). Goal setting and achievement under De Novo. General observations. VI. MCDM Applications in Business Management. Manpower planning. Manpower selection and allocation decisions. Assignment of persons to jobs. Financial planning. Marketing management. VII. MCDM Applications in Other Related Areas. Project crashing: time-cost tradeoff. Diffusion patterns of small industries. Project selection. A case of Asian preferential trade tariff arrangements. Model formulation. Model application: the case of the commodity sugar. Bicriterion transportation models: A case study. The models. Application of the model. Appendix. A Heuristic Algorithm for De Novo Programming. Subject Index. Author Index.

Discharge properties of single units in auditory part of reticular nucleus of thalamus in cat

1. Extracellular recordings from 153 single units were obtained in the auditory part of the reticular nucleus (RE) of the thalamus of anesthetized cats. 2. In absence of acoustic stimulation, the majority of RE units (75%) had a spontaneous activity characterized by bursts of spikes lasting over 30 ms, alternating with isolated discharges; in contrast, only 30% of units in the medial geniculate body (MGB) showed these long bursts during spontaneous activity. 3. For a majority of RE units (65%), activity evoked by noise bursts consisted in complex response patterns with multiple excitatory and/or inhibitory components. For this stimulus, most units (79%) showed nonmonotonic rate-intensity functions, and median response latency to the first excitatory component was 16 ms, which is slightly longer than that obtained in the anterior part of the ventral division of the MGB for the same conditions. 4. Frequency tuning to pure tones in RE was usually broad: the median value of the width of response ranges was five octaves in RE, as compared to two octaves in the ventral division of the MGB and three octaves in the medial division of the MGB. Responses to tones were complex, usually characterized by frequent changes of response pattern with frequency. No preferential arrangement of units as a function of their best frequency was found along a rostrocaudal or a dorsolateral to ventromedial axis. 5. The present study demonstrates that units in the auditory part of RE have discharge properties clearly different from the main auditory thalamic nucleus, the MGB.

Functional organization of the medial division of the medial geniculate body of the cat: Tonotopic organization, spatial distribution of response properties and cortical connections

The discharge properties of 735 single units located in the pars magnocellularis (M) of the medial division of the medial geniculate body (MGB) were studied in 23 nitrous oxide anesthetized cats in response to simple acoustic stimuli (clicks, noise and tone bursts). A systematic decrease of single unit characteristic frequencies (CF) was observed along electrode track portions crossing M from dorso-medial to ventro-lateral. These data indicate that M is tonotopically organized with an arrangement of low CF units latero-ventrally and high CF units dorso-medially. This preferential arrangement of single units as a function of their CF was consistent with the location and orientation of clusters of labeled cells in M resulting from wheat-germ agglutinin labeled with horseradish peroxidase (WGA-HRP) injections in CF defined loci in the anterior (AAF) or primary (AI) auditory cortical fields. The quality of the tonotopic arrangement was low caudally and increased in the rostral direction, indicating that this tonotopicity concerns mainly the anterior half of M. Response latencies to clicks, noise and tone bursts were on average longer in the posterior part of M than in its anterior part. Time-locking of discharges in response to repetitive acoustic pulses was more frequent anteriorly than posteriorly and the upper limiting rate of locking was on average higher rostrally (up to 200–300 Hz). In contrast, other response properties such as responsiveness to the various combinations of simple acoustic stimuli, response patterns and tuning were more randomly distributed in M, showing the whole range of respoase properties seen in the MGB. Data derived from several injections of WGA-HRP performed in distinct auditory cortical fields in several animals indicated that M projects to the tonotopic cortical fields (AAF, AI and PAF) as well as to the non-tonotopically organized secondary auditory cortex (AII). The contribution of M to the total thalamic input reaching each field of the auditory cortex was quantitatively more important for AAF (30%) and PAF (20%) than for AI and AII (about 10% each).

Intergranular fracture along migrated boundaries in ordered Ni 4Mo

The alloy Ni-20 at. % Mo is FCC and disordered (..cap alpha.. phase) above 868/sup 0/C, and below this temperature it forms a superlattice of the D1a type (..beta.. phase). Rapid cooling from the ..cap alpha.. region prevents the formation of ..beta... Reheating in the range 700-800/sup 0/C results in the relatively rapid formation of the ordered phase. The ordering reaction occurs by preferential arrangement of Ni and Mo atoms on the FCC lattice, so that the ..beta.. has a close packed structure and a crystallographic relation to the former ..cap alpha... Six crystallographic variants of ..beta.. form and three types of domain boundaries. Thus inside the ..cap alpha.. grains a fine domain structure forms with crystallographic continuity between the domains. It is only at the former ..cap alpha.. boundaries that high angle boundaries exist between ..beta.. crystals. Aging results in a coarsening of the domains and accompanying this coarsening is an increase in strength and a drastic reduction in ductility. For example, in the ..cap alpha.. form, the alloy has a ductility of about 60%, whereas aging at 775/sup 0/C for 3 min. reduces the ductility to about 5%. Fracture occurs along the former ..cap alpha.., high angle boundaries.

Preferential enrichment of chemistry at polymer surfaces

The preferential enrichment of specific chemical groups that occur at the surface of three classes of polymers was studied by means of X-ray photoelectron spectroscopy (XPS or ESCA). The material variables included bulk chemical composition, degree of crystallinity, and crosslinking. It was found that XPS is capable of detecting PET cyclic oligomers that were forced to the surface during crystallization. A new PET surface texture was observed by SEM on PET surfaces from which the oligomer crystals were extracted. A crystalline 1 : 1 alternating copolymer of ethylene/chlorotrifluoroethylene presented a preferential arrangement of ethylene segments closer to the surface relative to the chlorotrifluoroethylene groups. A small amount of contamination strongly affected that surface composition. In linear segmented polyurethanes, enrichment of the surfaces with soft segments occurred. However, this segregation seemed inhibited by crosslinking.

Temperature-dependent rheological behavior of Pluronic F-127 aqueous solutions

A Theological study of Pluronic F-127 aqueous solutions of 15–30% concentrations was undertaken at temperatures ranging from 15 ° C to 35 ° C. An exponential relationship was found between viscosity and temperature, with curve slopes depending upon Pluronic concentration. A theory is proposed to explain that phenomenon. It is based on the previously reported observation that pluronic micelles in water solution undergo a thermally induced swelling together with a desolvatation. The proposed hypothesis is, therefore, based on the creation of a cross-linked network. DSC and X-ray diffraction studies show this network consists of weak interactions (probably hydrogen bonds) accounting for the reversibility of the thermoviscosimetric behavior, and generates no preferential 3-dimensional arrangement.

The Effect of Multilateral Trade Clearinghouses on the Demand for International Reserves

This paper attempts to capture the portfolio incentives for central bank participation in a multilateral trade clearinghouse and to discuss the relation of those incentives to the volume of trade. Clearing­houses for the netting of multilateral intra-regional trade have existed since the 1950s, but no work to date has attempted to explore the incentive effects of such arrangements. Instead previous work, primarily empirical, has focused on the tendency of preferential arrangements (clearing as well as favorable protectionist policies) between nations to encourage trade flows between them. This paper advances the notion that the effects of clearing arrangements must be modelled as a portfolio choice problem, in order to ascertain the precise influence of clearing alone.The model developed here describes the choice of the central bank between holding reserve balances and investing in productive assets. For a given distribution of net export receipts and a given cash management policy of the central bank, expected daily demand for international reserves is derived. This demand is re-derived to illustrate the effects of a clearing­house; in addition, reserve demand is augmented to account for debt payments to external creditors.Regardless of whether the central bank makes external debt pay­ments, the clearing arrangement reduces the demand for reserves to finance trade. It is possible, were the "freed" reserves invested in development of the export industry, that the clearing arrangement could translate into an increased volume of trade. If the country is burdened with external debt payments however, it is possible that the "freed" reserves would simply be used to increase payments to external creditors.

Correlation between the atomic and electronic structure of metallic glasses

57Fe Mossbauer and photoemission measurements were performed on meltquenched amorphous Fe(Zr, B) and (Fe, Ni)B alloys. The atomic and electronic structure of Fe90Zr10 and Fe88B12 glasses were found to be different. Half of the Zr content could be replaced by B in the Fe90Zr10 glass without changing its structure. Mossbauer investigation of the amorphous (Fe1−xNix)100−yBy (0<=x<=0.80, 12<=y<=40) system indicates preferential arrangement of Fe and Ni atoms on the transition metal sites. According to the present XPS measurements there is a remarkable shift of 0.5 eV to higher binding energies of the B ls core level energy in the Ni rich glasses compared to Fe88B12 corresponding to a stronger binding between the Ni and the B atoms than that of Fe and B.

The Caribbean Sugar Crisis: Consequences and Challenges

“Being in Sugar is like collecting Confederate currency”. This assessment, offered by anthropologist Sidney Mintz (1985), is shared by many sugar industry observers, insiders, and, increasingly, by many Caribbean officials. King sugar, instrumental in shaping the diverse political, economic, and social histories of the Caribbean since colonial times, confronts a seemingly intractable crisis: a severe, and sustained, disequilibrium between global demand and supply which makes export of sugar very unattractive. Except in those cases where preferential arrangements exist between producers and consumers-the Lomé Convention, the US sugar quota system, and the Soviet guaranteed purchase of Cuban sugar-world prices for sugar are at a record low, well below production costs.

Evidence of a distribution difference between two gangliosides in bilayer membranes

Freeze-etch electron microscopy, a platinum shadowing technique, has been used to compare the lateral distribution of several gangliosides in bilayer model membranes by directly visualizing bound lectin molecules. In particular, GM 1 and GD 1a, major components of brain ganglioside, were studied in phase-separated mixtures of dipalmitoyl- and dielaidoylphosphatidylcholines exposed to Ricinus communis agglutinin and wheat germ agglutinin. The distribution of glycolipid showed evidence of microheterogeneity in that bound lectin tended to occur in clusters of several or more molecules. With GD 1a as receptor such clusters were small and very uniformly distributed over the membrane surface. Somewhat larger, irregularly spaced clusters of up to a dozen lectin particles were more typical of membranes bearing GM 1 and, in addition, there were occasional extensive patches of bound lectin coexisting with areas apparently devoid of glycolipid receptor in phase-separated mixtures of dipalmitoyl- and dielaidoylphosphatidylcholine. Gangliosides in the latter mixtures were not obviously influenced in their lateral distribution by the presence of coexisting fluid and rigid domains. These basic observations seem to extend to bilayer membranes containing mixtures of two gangliosides. The patterns of lectin binding were not grossly affected by incubation time or history of warming and cooling. This study was extended to bilayers of pure dipalmitoylphosphatidylcholine in expectation that the distinctive features characteristic of the P β′ phase of this lipid might accentuate any behavioural differences between GM 1 and GD 1a.GM 1 was found to exist preferentially in the ‘trough’ regions between P β′ ripples, while GD 1a showed no apparent preferential arrangement. Given that bound lectins adequately reflect glycolipid distribution in membranes, it would appear that structurally different glycolipids from the same host membrane can assume different distributions on the basis of interactions with defined lipid host matrices.

Hydration Shell Structures in an MgCl2 Solution from X-Ray and MD Studies

Abstract The results of a molecular dynamics simulation of a 1.1 molal aqueous MgCl2 solution are com-pared with newly performed x-ray measurements. The structural properties of the solution are evaluated from the scattering data by a model fit to the experimental structure function. The comparison on the basis of fit parameters and partial structure functions shows an overall good agreement between experiment and simulation. Detailed information on the structure of the hydration shells is deduced from the simulation and shown in form of density maps and angular distributions. It is demonstrated that the octahedral arrangement of the water molecules in the first hydration shell of Mg++ is strongly pronounced while it is only indicated in the case of Cl-. A preferential arrangement in tetrahedral directions has been found for the nearest neighbor water molecules around a central water molecule with an asymmetry in respect to lone pair and hydrogen atom directions. In addition, the probability of finding water molecules at a given number of symmetry sites at the same time has been calculated.

The overall morphology of neuromuscular junctions as revealed by scanning electron microscopy.

Skeletal neuromuscular junctions (NMJs) of vertebrates were examined by scanning electron microscopy after removal of connective tissue components by HCl hydrolysis. In addition to the surface texture of NMJs, the subsynaptic organization of the sarcolemma was visualized in specimens in which nerve endings were detached from the muscle surface. A remarkable morphological variability between animal species was observed. The NMJs in the frog sartorius muscle consisted of longitudinal ribbon-like endings which fitted into a shallow synaptic gutter containing highly ordered cross-bands of junctional folds. The NMJs of the posterior latissimus dorsi muscle of the zebra finch were characterized by varicose swellings of the nerve endings which fitted into a round pit of the sarcolemma. NMJs in the sternothyroid muscle of the Chinese hamster consisted of thin ramified endings which were confined to an oval area on the muscle surface. The labyrinthine synaptic groove contained well-developed junctional folds without preferential spatial arrangement. The procedure used for the present study illustrates in great detail the terminal arborization of the motor nerve ending and the surface features of the subsynaptic sarcolemma. It may also allow quantitative study of the synaptic morphology of NMJs.

International Trade and Industrial Organization: Introduction

UNITED STATES economists may deserve credit for having promoted the statistical investigation of hypotheses about industrial organization. But theyand their less numerate forebears-must shoulder blame for our habitual acceptance of 'the nation' as the presumed geographic span of the market. The power of international competition to shape market structure and performance seemed modest in the giant US economy. The analytically messy problem of drawing appropriate market boundaries has not attracted the theorists. So one can readily understand the neglect of international forces prevalent in industrial organization research until the past decade (for a literature survey, see [3]). That neglect has become an increasing embarrassment, of course, as international links among national product markets have grown and revealed their influence to the naked eye. The unholy alliance between the tariff collector and the local monopolist is a long-standing one. Since World War II tariff barriers have been reduced substantially, and international trade (especially in manufactures) has grown more rapidly than national production in the industrial countries. The European Community and lesser preferential arrangements have taken bold steps toward erasing the economic barriers of national frontiers. The pervasive expansion of intraindustry trade shows that much of the enlargement of international commerce takes the form of increasingly fine division of labor within industries, rather than the sectoral specialization assumed in classical discussions of comparative advantage-this to the discomfiture of international-trade economists weaned on models of pure competition. Perhaps knowledge of the structure of international trade can be surmounted only if an industrial-organization economist is included in the climbing party! One might hope that internationalizing the field of industrial organization would greatly simplify its conceptual structure. If buyers and sellers the world around comprise 'the market' and the individual nation's transactors are a small fraction of the total, then the national market becomes a pricetaking subsector of the world market. Measures of national seller and buyer concentration lose their economic meaning, and enthusiasts for competition policy can confine their efforts to the occasional noisy demonstration at the front door of the tariff-setting authority. Alas, theoretical and empirical research have shown that the recognition of international influences on competition in the national market makes the subject more rather than less

Calcium-isotope effects in mechanical spectra of cancellous bone.

An additional analysis of dynamic mechanical data previously reported for human cancellous bone is presented. This analysis indicates that preferential arrangements of the small numbers of Ca44 atoms (∼2%) within apatite structures of bone minerals may occur and have a disproportionate influence on the macroscopic response of bone to mechanical vibrations. Similar preferential or localised arrangements of particular atomic isotopes might have physiological as well as mechanical consequences in bone and other biomaterials.

Abstract: Magnetic properties of rare earth−transition metal amorphous thin films

Considerable interest has been created recently in the preparation and magnetic properties of rare earth(RE) −transition metal(TM) binary amorphous thin films. The specific binary systems of primary interest have been Gd−Co1 for its induced uniaxial anisotropy, Ku, and its associated properties which make it attractive for magnetic bubble and magneto−optic devices, and TbFe22 for its large coercivity, magnetostriction, energy product, and permanent magnet applications. In addition to their technological significance, their properties have resulted in the two prevailing, but contradicting, theories of magnetic exchange in amorphous systems, namely the local anisotropy3 and charge transfer4 models. This report presents the results of an investigation in which (1) we systematically studied the magnetic properties of Ho−Co and Ho−Fe amorphous thin films over a wide compositional range in order to judge the validity of the two theories, and (2) we measured the temperature dependence of Ku in Gd−Co, Ho−Co, and ...

Effect of Processing Factors and Fiber Properties on the Arrangement of Fibers in Blended Yarns

A study was made of the influence of processing factors on the average disposition of fibers within a section and on the intimacy of mixing, when the blending constituents differ widely with respect of fiber dimensions. A simplified measure was developed to characterize the preferential arrangement of fibers within a cross section, and the effects of spinning factors were evaluated. It was found that long and fine fibers have a definite tendency to occupy the core, while short and coarse fibers concentrate at the surface, and of the spinning factors, only strand width at the delivery nip has a significant effect on the arrangement. Further, no significant preferential segregation of the constituents was noticed across the width of the drafted strand, indicating that the biased arrangement develops during spinning. Spinning from multiple rovings showed promise of improving the preferential arrange ment, but the average position of the constituent in the yarn section does not have any large effects on the strength or the extension of the yarn. When blending is done prior to the card, intimate mixing of the components, close to ideal, is realized in the yarn even in blends composed of fibers that differ considerably in length and fineness. But with blending at the ring frame, the components are distributed almost independently of each other and, in such yarns, the variability in the blend proportion is of the same order as the variability in the total number of fibers. Evidence is presented to show that adjoining fibers tend to move together during drafting, and in order to minimize variation in the blend proportion longitudinally, adequate lateral intermingling of the components must be obtained.

Entropy of Mixing of Liquid NaCd System

The observed asymmetric behaviour of mixing properties of NaCd liquid alloys, with smaller negative value for excess free energy of mixing (-4.4919KJ) has aroused our interest to undertake a theoretical investigation of this system.The existence of an intermetallic compound in the solid phase, which is manifested in the phase diagram, may be one of the factors for the anomalous behaviour of property of mixing. A simple statistical mechanical theory based on complex formation model (the complex is formed by the preferential arrangement of A and B constituent atoms of the alloy AB ;( μA + νB = Aμ Bν) has been used to investigate the phenomena of compound formation in NaCd liquid alloys through the study of entropy of mixing through out the whole concentration range.Nepal Journal of Science and Technology Volume 10, 2009 December Page: 105-107

Remarks on A Formula for Preferential Arrangements

Remarks on A Formula for Preferential Arrangements