Showing papers by "Northwestern University published in 1972"

A Generic Concept of Marketing

Abstract: The proposal that marketing is relevant to all organizations having customer groups was advanced in the January, 1969 issue of this journal. It is now stated that the original broadening proposal s...

Nonlinear water diffusion in nonsaturated concrete

Abstract: The equations governing drying and wetting of concrete are formulated, assuming the diffusivity and other material parameters to be dependent on pore humidity, temperature and degree of hydration. By fitting of computer solutions for slabs, cylinders and spheres against numerous test data available in the literature it is found that the diffusion coefficient decreases about 10 to 20 times when passing from 0.9 to 0.6 pore humidity. The problem is thus strongly nonlinear. Dependence on temperature is found to agree satisfactorily with the rate process theory. Effect of temperature on equilibrium pore humidity is also studied. The aging effect is defined by means of an equivalent hydration period. To enable easy prediction of drying of simple bodies, charts for the solution in terms of nondimensional variables are presented. Finally, correlation to the diffusion in a saturated concrete is discussed.

An approach to the dizzy patient.

Abstract: m Although dizziness is a nearly ubiquitous complaint, few physicians other than otologists have devoted more than passing interest in recent years to the evaluation of this symptom. The attention of the otologists has been focused on the vestibular disorders about which such tests as bithermal caloric stimulation and electronystagmography (ENG) have provided much d a t a and some valuable understanding.’ -l Considerably less effort has been directed to the evaluation of other medical problems that may present with a similar complaint of dizziness. These include neurological, card iac , psychiatric, hematologic, vascular, ophthalmological, and other disorders, many of which are well understood but are not as closely identified with the complaint of dizziness. Our own experience in a university neurological outpatient clinic indicated that only a minority of patients with the complaint of dizziness suffered from vestibular disorders. Efforts to evaluate the causes of dizziness in the remaining patients’ were haphazard, and the id en tification of underlying cardiac arrhythmias, orthostatic hypotension, Bruns’s apraxia of gait, and a spectrum of other disorders was sporadic and unreliable. The need for a more systematic approach to t h e diagnosis of dizziness prompted the development of a model “dizziness clinic” designed to bring to bear the insights of several medical specialties, using an organized method of collecting data on each patient. The goals of t h e clinic, in addition to improving the

Problems of Translation in Cross-Cultural Research

Abstract: There are various types of translation problems, not all of which have received sufficient attention. Translation of questions or other verbal stimuli has received more attention than problems of achieving equivalence in translations of orienting and task in-structions and responses. Vocabulary equivalence must take into account language as used by respondents and the possibility of terms lacking equivalents across languages. Equivalence in idiom and in grammar and syntax may be important, but equivalence in terms of experiences and concepts tapped is probably most important of all. Direct translation cannot be assumed to produce equivalent versions of verbal stimuli. Back-translation is not only achievable but is likely to be highly satisfactory if care is taken in its use, especially in locating translators facile in the actual language of target subjects. While the de-centering proposals of Werner and Campbell have much to recommend them, de-centering becomes progressively difficult as one goes from tw...

Dynamo Action of Fluid Motions with Two-Dimensional Periodicity

Abstract: In a previous paper it has been established that almost all spatially periodic motions of an infinite homogenous conducting fluid give magnetohydrodynamic dynamo action for almost all values of the magnetic diffusivity or resistivity A. It was shown that there is a dynamo action if and only it or some real vector j there is a growing magnetic field solution of the form where the complex vector function H(x) has the same periodicity as the motion. The complex growth rate b was studied in a first-order limit of small j to obtain the above result. In this sequel the special case of spatially periodic motions with their three components functions of the two Cartesian coordinates y and z only is considered. The first-order method establishes dynamo action for only half, in a certain sense, of the motion-resistivity combinations. It is shown that the two-dimensional spatially periodic motion u = (cos y — cos z, sin z, sin y) is a first-order dynamo, at least for almost all resistivities. Three similar motions, which are not firstorder dynamos for any resistivity, are also studied. It is proved that multiple-scale versions of all three can give growing magnetic fields for certain resistivities when terms of higher order in j are included. Heuristic descriptions of all four dynamo mechanisms are given. A numerical method is described for determining the most rapidly growing magnetic field solution ot toe above form, and results for all four motions are presented, giving the growth rate R e/, as a function of j for a range of resistivities A down to about 10~a. The first motion gives growing solutions for all resistivities in this range, the others give dynamo action only for resistivities below critical values near unity. The numerical and analytic results agree.

Cochlear inner and outer hair cells: functional differences.

Abstract: The cochlear microphonic response was measured with differential electrodes from the first and third cochlear turns of normal guinea pigs and those treated with the ototoxic drug kanamycin. Histological controls showed that the outer hair cells in treated animals were missing over the basal half of the damaged cochleas, while the inner hair cells were intact. Measurements are consistent with the hypothesis that the potentials produced by inner hair cells are proportional to the velocity of the basilar membrane, whereas potentials generated by outer hair cells (which dominate the response of normal cochleas) are proportional displacement of the basilar membrane.

Mechanism of d-Cycloserine Action: Alanine Racemase from Escherichia coli W

Abstract: The antibiotic d-cycloserine is an effective inhibitor of alanine racemase. The lack of inhibition by l-cycloserine of alanine racemase from Staphylococcus aureus led Roze and Strominger to formulate the cycloserine hypothesis. This hypothesis states that d-cycloserine has the conformation required of the substrates on the enzyme surface and that l-cycloserine cannot have this conformation. Alanine racemase from Escherichia coli W has been examined to establish whether these observations are a general feature of all alanine racemases. The enzyme (molecular weight = 95,000) has Michaelis-Menten constants of 4.6 × 10−4m and 9.7 × 10−4m for d- and l-alanine, respectively. The ratio of Vmax in the d- to l-direction is 2.3. The equilibrium constant calculated from the Haldane relationship is 1.11 ± 0.15. Both d- and l-cycloserine are competitive inhibitors with constants (Ki) of 6.5 × 10−4m and 2.1 × 10−3m, respectively. The ratio of Kmd-alanine to Kid-cycloserine is 0.71, and the ratio of Kml-alanine to Kil-cycloserine is 0.46. Since l-cycloserine is an effective inhibitor, it is concluded that the cycloserine hypothesis does not apply to the enzyme from E. coli W.

Fibrinoligase: the fibrin‐stabilizing factor system of blood plasma*

Abstract: A glance at FIGURE l a reveals the built-in regulatory features of the physiological process in vertebrates. I t may be noted that the scheme was derived entirely from a study of the individual reaction steps in isolated systems. A complete description would require insertion of additional intermediates, and FIGURE l a is to be taken only as a minimal representation without which (as we shall see later) correct differential diagnosis of disorders in this field simply would not be possible. Thrombin was shown to act as a proteolytic enzyme both l-* on fibrinogen and on fibrin-stabilizing factor (Factor XIII) .t It coordinates the appearance of fibrin with the formation of fibrinoligase from its zymogen. As such, the physiologically important sequence of clotting followed by enzymatic crosslinking is ensured. Clotting in lobster plasma (FIGURE lb ) does not seem to depend on hydrolysis by a thrombin-like enzyme, and the process can be conceived of as a rudimentary shunt of the more complicated system typical for vertebrates. In Homarus, an intracellular transamidase (transglutaminase) functions as the clotting enzyme.\"-\" It is released during clumping of amoebocytes or during damage to muscle tissue. Intracellular compartmentalization of the already active enzyme is apparently the only means of control for preserving the fluidity of lobster plasma. Small synthetic amines which inhibit fibrinol i g a ~ e , ~ also inhibit the lobster enzymeeR These compounds affect only the cross-linking step in vertebrates and do not interfere with the appearance of a clot. When added to lobster plasma, they delay the onset of clotting itself. Although fibrinoligase and the lobster enzyme both belong to a group of enzymes which catalyze the calcium-dependent incorporation of amines into proteins (e.g., putrescine into casein), their specificities for the natural substrates are so different that they cannot be readily interchanged. In a phenomenological

Calcium binding to intestinal membranes

Abstract: Flame photometry reveals that glutaraldehyde and buffer solutions in routine use for electron microscopy contain varying amounts of calcium. The presence of electron-opaque deposits adjacent to membranes in a variety of tissues can be correlated with the presence of calcium in the fixative. In insect intestine (midgut), deposits occur adjacent to apical and lateral plasma membranes. The deposits are particularly evident in tissues fixed in glutaraldehyde without postosmication. They are also observed in osmicated tissue if calcium is added to wash and osmium solutions. Deposits are absent when calcium-free fixatives are used, but are present when traces of CaCl2 (as low as 5 x 10-5 M) are added. The deposits occur at regular intervals along junctional membranes, providing images strikingly similar to those obtained by other workers who have used pyroantimonate in an effort to localize sodium. Other divalent cations (Mg++, Sr++, Ba++, Mn++, Fe++) appear to substitute for calcium, while sodium, potassium, lanthanum, and mercury do not. After postfixing with osmium with calcium added, the deposits can be resolved as patches along the inner leaflet of apical and lateral plasma membranes. The dense regions may thus localize membrane constituents that bind calcium. The results are discussed in relation to the role of calcium in control of cell-to-cell communication, intestinal calcium uptake, and the pyroantimonate technique for ion localization.

Effect of adenosine 3'-5'-cyclic monophosphate on cell proliferation

Abstract: Secondary cultures of human diploid fibroblasts, which demonstrate density-dependent inhibition of cell growth, were used to study the effect of adenosine 3'-5'-cyclic monophosphate (cAMP) on cell proliferation. DNA synthesis in nonconfluent cultures and in contact-inhibited cultures stimulated to grow by refeeding with fresh medium was found to be inhibited by exogenous cAMP. The properties of this inhibition of DNA synthesis, together with the alterations in cAMP metabolism observed in confluent cultures of cells stimulated with fresh medium to resume growth, strongly suggest that cAMP is involved in contact-inhibition of cell proliferation.

On the Genetics of Altruism and the Counter-Hedonic Components in Human Culture1

Abstract: Man is more similar to the social insects than to the wolf and chimpanzee in complex social coordination, division of labor, and self-sacrificial altruism. In the social insects, the behavioral dispositions involved are genetically determined, an evolution made possible by the absence of genetic competition among the cooperators. In man, genetic competition precludes the evolution of such genetic altruism. The behavioral dispositions which produce complex social interdependence and self-sacrificial altruism must instead be products of culturally evolved indoctrination, which has had to counter self-serving genetic tendencies. Thus unlike the social insect, man — as Freud noted — is profoundly ambivalent in his social role.

Does Intelligence Cause Achievement?: A Cross-Lagged Panel Analysis

Abstract: The literature of cognitive development has produced two opposing models of mental growth. One holds that the acquisition of concrete mental skills causes the later development of higher order organizational schema or rules. The contrasting model postulates a progression in which the initial acquisition of larger schema results in the increased capacity to acquire new concrete skills. While both probably operate to some extent, an attempt was made in this research to determine the preponderant developmental sequence. The scores of 5,495 students who had taken intelligence and achievement, tests in both fourth and sixth grades were analyzed through the use of the cross-lagged panel correlation technique. For students of suburban schools (N = 3,994), the abstract-to-concrete causal sequence predominated, while among inner-city school children, the opposite held. The specific causal relationships between skills assessed on the various subscales of the tests employed, the value of the cross-lagged panel correlation technique in causal analysis, and an extensive methodological examination and qualification of this analytic model are presented.

On the homology of non-connected monoids and their associated groups

Abstract: Nutzungsbedingungen Mit dem Zugriff auf den vorliegenden Inhalt gelten die Nutzungsbedingungen als akzeptiert. Die angebotenen Dokumente stehen für nicht-kommerzielle Zwecke in Lehre, Forschung und für die private Nutzung frei zur Verfügung. Einzelne Dateien oder Ausdrucke aus diesem Angebot können zusammen mit diesen Nutzungsbedingungen und unter deren Einhaltung weitergegeben werden. Die Speicherung von Teilen des elektronischen Angebots auf anderen Servern ist nur mit vorheriger schriftlicher Genehmigung des Konsortiums der Schweizer Hochschulbibliotheken möglich. Die Rechte für diese und andere Nutzungsarten der Inhalte liegen beim Herausgeber bzw. beim Verlag.

Can Private Brand Buyers be Identified

Abstract: Much marketing research in the past ten years has been directed to identifying managerially meaningful and behaviorally sound consumer market segments. Results have, in general, shown that psychological and demographic measures have not been terribly good criterion variables for segmentation. Marketers have attempted to find the deal prone consumer [10], the heavy user [4], new brand buyers [7], and private brand buyers [6]; these market segments represent large areas of economic and marketing effort in the real world. The evidence from these studies has suggested that measures which are more closely tied to purchase behavior would be better predictors. This research attempted to examine buyers or potential buyers of vastly different products to see if meaningful segments could be created using a model of consumer behavior including demographic, product class salience, product use, and marketing attitude variables. Factor analysis, multiple discriminant analysis, and cross-tabulation were used to test the model, and the results were more encouraging than those of similar recent experiments. While economists have been interested in costs of dis-

Macromolecule-small molecule interactions; introduction of additional binding sites in polyethyleneimine by disulfide cross–linkages

Abstract: Polyethyleneimine and its acyl derivatives have been thiolated with thiobutyrolactone and the SH groups introduced have been crosslinked in the presence of and in the absence of methyl orange, respectively. After crosslinking of the polymers, the bound methyl orange was removed. The resultant two kinds of crosslinked polymers have been examined for their ability to bind methyl orange. The polymer crosslinked in the presence of methyl orange shows more binding sites and stronger binding than does the polymer crosslinked in the absence of methyl orange. It seems, therefore, that the conformation of the polymer may be molded to provide sites that can accommodate a specific small molecule.