Showing papers by "State University of New York System published in 1980"
Book•
01 Jan 1980TL;DR: This newly expanded and updated second edition of the best-selling classic continues to take the "mystery" out of designing algorithms, and analyzing their efficacy and efficiency.
Abstract: ....The most comprehensive guide to designing practical and efficient algorithms!.... The Algorithm Design Manual, Second Edition "...the book is an algorithm-implementation treasure trove, and putting all of these implementations in one place was no small feat. The list of implementations [and] extensive bibliography make the book an invaluable resource for everyone interested in the subject." --ACM Computing Reviews "It has all the right ingredients: rich contents, friendly, personal language, subtle humor, the right references, and a plethora of pointers to resources."-- P. Takis Metaxas, Wellesley College "This is the most approachable book on algorithms I have." -- Megan Squire, Elon University, USA This newly expanded and updated second edition of the best-selling classic continues to take the "mystery" out of designing algorithms, and analyzing their efficacy and efficiency. Expanding onthe first edition, the book now serves as the primary textbook of choice for algorithm design courses while maintaining its status as the premier practical reference guide to algorithms for programmers, researchers, and students. The reader-friendly Algorithm Design Manual provides straightforward access to combinatorial algorithms technology, stressing design over analysis. The first part, Techniques, provides accessible instructionon methods for designing and analyzing computer algorithms. The second part, Resources, is intended for browsing and reference, and comprises the catalog of algorithmic resources, implementations and an extensive bibliography. NEW to the second edition: Doubles the tutorial material and exercises over the first edition Provides full online support for lecturers, and a completely updated and improved website component with lecture slides, audio and video Contains a unique catalog identifying the 75 algorithmic problems that arise most often in practice, leading the reader down the right path to solve them Includes several NEW "war stories" relating experiences from real-world applications Provides up-to-date links leading to the very best algorithm implementations available in C, C++, and Java ADDITIONAL Learning Tools: Exercises include "job interview problems" from major software companies Highlighted take-home lesson boxes emphasize essential concepts Provides comprehensive references to both survey articles and the primary literature Exercises points to relevant programming contest challenge problems Many algorithms presented with actual code (written in C) as well as pseudo-code A full set of lecture slides and additional material available at www.algorist.com Written by a well-known algorithms researcher who received the IEEE Computer Science and Engineering Teaching Award, this new edition of The Algorithm Design Manual is an essential learning tool for students needing a solid grounding in algorithms, as well as a special text/reference for professionals who need an authoritative and insightful guide. Professor Skiena is also author of the popular Springer text, Programming Challenges: The Programming Contest Training Manual.
1,272 citations
TL;DR: In this article, the major-element, trace-element and isotopic compositions of approximately 1200 basalts (Mg +Fe 2+ ) > 65 ] IAB and MORB are similar, but differ significantly from IPB.
668 citations
TL;DR: In this paper, it is shown that there is a unique boundary between solutions which exist on the whole real line and solutions which, while tending to zero at plus infinity, blow up at a finite x.
Abstract: The differential equation considered is \(y'' - xy = y|y|^\alpha \). For general positive α this equation arises in plasma physics, in work of De Boer & Ludford. For α=2, it yields similarity solutions to the well-known Korteweg-de Vries equation. Solutions are sought which satisfy the boundary conditions (1) y(∞)=0 (2)
$$y{\text{(}}\infty {\text{)}} = {\text{0}}$$
(1)
$$y{\text{(}}x{\text{) \~( - }}\tfrac{{\text{1}}}{{\text{2}}}x{\text{)}}^{{{\text{1}} \mathord{\left/ {\vphantom {{\text{1}} \alpha }} \right. \kern-
ulldelimiterspace} \alpha }} {\text{ as }}x \to - \infty $$
(2)
It is shown that there is a unique such solution, and that it is, in a certain sense, the boundary between solutions which exist on the whole real line and solutions which, while tending to zero at plus infinity, blow up at a finite x. More precisely, any solution satisfying (1) is asymptotic at plus infinity to some multiple kA i(x) of Airy's function. We show that there is a unique k*(α) such that when k=k*(α) the condition (2) is also satisfied. If 0 k* then the solution blows up at a finite x. For the special case α=2 the differential equation is classical, having been studied by Painleve around the turn of the century. In this case, using an integral equation derived by inverse scattering techniques by Ablowitz & Segur, we are able to show that k*=1, confirming previous numerical estimates.
451 citations
TL;DR: In this paper, the authors apply the technique of dimensional reduction to both supersymmetric and non-supersymmetric theories, and show that in the latter case the technique is a viable alternative to conventional dimensional regularization.
430 citations
01 Jan 1980
TL;DR: This review discusses how proteins are localized in their final locations in the envelope of Escherichia coli and a hypothesis (loop model) is proposed to explain the possible functions of the peptide extension during the mechanism of secretion across the cytoplasmic membrane.
Abstract: The envelope of Escherichia coli consists of two distinct membranes, the outer membrane and the cytoplasmic membrane. The space between the two membranes is called the periplasmic space, and each fraction contains its own specific proteins. In this review, it is discussed how proteins are localized in their final locations in the envelope. Proteins localized in the outer membrane and the periplasmic space as well as transmembranous proteins in the cytoplasmic membranes appear to be produced from their precursors which have peptide extensions of about 20 amino acid residues at the amino terminal ends. General features for the peptide extension are deduced from the known sequences of the peptide extensions, and, based on their known properties, a hypothesis (loop model) is proposed to explain the possible functions of the peptide extension during the mechanism of secretion across the cytoplasmic membrane.
383 citations
TL;DR: In this paper, the authors call attention to "organizational symbolism", an important aspect of all institutions that has been virtually ignored, and suggest questions for a comprehensive research program for studying this topic.
Abstract: Our basic purpose in this paper is twofold: (1) to call attention to “organizational symbolism,” an important aspect of all institutions that has been virtually ignored, and (2) to suggest questions for a comprehensive research program for studying this topic.
333 citations
TL;DR: A measure of the non-coaxiality involved in progressive deformation histories is proposed in the form of the kinematical vorticity number, Wk as mentioned in this paper, which measures the relative effects of rotation of material lines (relative to the instantaneous stretching axes) and of stretching of these material lines.
328 citations
TL;DR: The expectations and variances of coefficients of variation under the assumption of normality are reviewed and the effects of appreciable departures from this assumption are examined.
Abstract: Sokal, R. R., and C. A. Braumann (Department of Ecology and Evolution, State University of New York at Stony Brook, Stony Brook, New York 11794) 1980. Significance tests for coefficients of variation and variability profiles. Syst. Zool. 29:50-66.-The distribution of sample estimates of the coefficient of variation is studied analytically and by Monte Carlo simulation. Derivations are given for the expected value of a coefficient of variation and for its standard error. Various proposed standard errors for coefficients of variation are evaluated. Standard errors are derived for differences between coefficients of variation for samples of independent and correlated characters. Methods are proposed for testing the homogeneity of sets of independent and correlated coefficients of variation. Tests of homogeneity of variability profiles as well as for parallelism of such profiles are furnished. [Coefficients of variation, variability profiles.] The employment of coefficients of variation in systematic research is of long standing. Various evolutionary hypotheses require for their examination the establishment of differences in the amounts by which characters vary in populations. Such differences can be examined for the same character across several populations of the same species or of different species, or the comparison may be within the same population but among different characters. Such comparisons of the amounts of variation are generally adjusted for differences in magnitude of the character means, hence the employment of the coefficient of variation, V. A recent renewal of interest in the coefficient of variation is due to two developments. Various studies, collectively called population phenetics, have probed the effects of evolutionary processes on variability patterns in animal and plant populations and have tried to establish the converse-the drawing of inferences about evolutionary processes from observed variability patterns. Studies such as those of Soule (1967), Soule and Stewart (1970), Rothstein (1973), Lande (1977), or Sokal (1976) come to mind readily. A second reason for an increased interest in coefficients of variation is the stimulating book by Yablokov (1974) introducing the study of variability profiles in mammalian populations. Variability profiles are graphs in which the amount of variation expressed as a variance or coefficient of variation is plotted against a horizontal axis representing the suite of characters under study. Examination of variability profiles within and among populations leads to inferences about the amount of developmental (and ultimately evolutionary) control of variability for different characters in the same population and among populations. There is a need for appropriate methods to examine the types of comparisons being considered. In this paper we shall briefly review the expectations and variances of coefficients of variation under the assumption of normality and examine the effects of appreciable departures from this assumption. We shall then turn to the comparison of two or more coefficients of variation for the same character from different populations. This account will be followed by a discussion of tests applicable to a single variability profile, which in turn will lead to the comparison of several profiles. These can be considered for the same hierarchic level, as in local population samples of the same species, or the comparison may be between different hierarchic levels representing natural sampling units, such as variability within local populations versus variability across populations. Analytical work on the expectations
315 citations
TL;DR: In this paper, an independent discussion of these field theories is given, based on a hierarchy of generalized Christoffel symbols with simple gauge transformation properties, and the necessity of certain constraints on gauge fields and parameters is easily seen.
Abstract: Free-field theories for symmetric tensor and tensor-spinor gauge fields have recently been obtained which describe massless particles of arbitrary integer or half-integer spin. An independent discussion of these field theories is given here, based on a hierarchy of generalized Christoffel symbols with simple gauge transformation properties. The necessity of certain constraints on gauge fields and parameters is easily seen. Wave equations and Lagrangians are expressed in terms of the Christoffel symbols, and the independent modes of the system are counted in covariant gauges. Minimal-coupling inconsistency and a combined system of higher-spin boson gauge fields interacting with relativistic particles is discussed.
307 citations
TL;DR: A regular slow wave theta rhythm can be recorded in the medial entorhinal cortex (MEC) of freely moving rats during voluntary behaviors and paradoxical sleep.
298 citations
TL;DR: By examining both the transformation efficiency of yeast of various plasmids containing defined regions of the 2 mu circle genome and the characteristics of the resultant transformants, it is determined that efficient use of the2 mu circle origin requires some function or functions encoded in the molecule at a site away from the origin.
TL;DR: Five types of recovery patterns from hypoxia are designated depending upon the nature of the O2 debt, and three types of conformers are designatedDepending upon the extent to which they compensate anaerobically for a drop in P1O2.
TL;DR: It is shown that three basic models of the Flory-Stockmayer theory of polymerization may all be described directly by means of a kinetic rate equation of a form first discussed by Smoluchowski, and correspond to the three known classes of solutions to this equation.
Abstract: It is shown that three basic models of the Flory-Stockmayer theory of polymerization may all be described directly by means of a kinetic rate equation of a form first discussed by Smoluchowski, and correspond to the three known classes of solutions to this equation. The kinetics of gelation are discussed from the rate equation; the nature of both the Flory and the Stockmayer gelation theories is shown, and a new model of gelation is proposed. Some new solutions to Smoluchowski's equation are given in an appendix.
TL;DR: In this article, a new class of actions without ghosts and tachyons is found in which both the vierbein field and the spin connection are independent and propagating fields.
Abstract: A new class of ${R}^{2}$ type of actions without ghosts and tachyons is found in which both the vierbein field ${{e}_{\ensuremath{\mu}}}^{a}$ and the spin connection ${{\ensuremath{\omega}}_{\ensuremath{\mu}}}^{\mathrm{ab}}$ are independent and propagating fields. A complete set of spin-projection operators for ${{e}_{\ensuremath{\mu}}}^{a}$ and ${{\ensuremath{\omega}}_{\ensuremath{\mu}}}^{\mathrm{ab}}$ is constructed. The particle content of these actions and other ${R}^{2}$ theories in the literature is given. The relation of this work to the interesting work of Neville is discussed.
TL;DR: In this article, the trace anomaly is identified with the Jacobian factor for the functional measure under the conformal transformation in the path-integral formalism, and the pathintegral formulation of anomalous Ward-Takahashi identities is then translated into a simple algebraic characterization of chiral and conformal anomalies.
Abstract: It is shown that the trace anomaly is also identified with the Jacobian factor for the functional measure under the conformal transformation in the path-integral formalism The path-integral formulation of anomalous Ward-Takahashi identities is then translated into a simple algebraic characterization of chiral and conformal anomalies This exemplifies some of the common features shared by the topological and nontopological anomalies
TL;DR: The authors studied how closely the locational pattern of foreign-owned subsidiaries in the U.S. corresponds to the spatial distribution of American domestic firms and found that foreign investors have a strong preference for regions outside the country's traditional manufacturing heartland.
Abstract: The recent, dramatic increase in the flow of foreign direct investment capital into the American manufacturing sector raises the question of how closely the locational pattern of foreign-owned subsidiaries in the U.S. corresponds to the spatial distribution of American domestic firms. Although foreign investors have generally lagged behind the spatial decentralization tendencies of American manufacturers, their most recent locational choices within the U.S. have revealed a strong preference for regions outside the country's traditional manufacturing heartland.
TL;DR: In this paper, it was shown that a change in perceived lightness was not caused by a change of perceived spatial position, with no important change in the retinal image, but rather by the amount of light reflected by a surface.
Abstract: Experiments have recently been reported in which a decisive change in perceived lightness was produced by a change in perceived spatial position, with no important change in the retinal image. A number of previous studies had found little or no such effect. Experiments of the kind that produced these effects and of the kind that do not produce these effects are presented here. The main differences between these two kinds of experiments are discussed. One difference is whether the display allows the target to be part of one ratio in one spatial position but another in the other spatial position. Another difference concerns the range of luminances within the display. Also discussed are the implications of these findings for cognitive vs. S-R theories, the order of processing depth and lightness, laboratory data vs. experience, the role of lateral inhibi tion in lightness perception, and theories of lightness perception in general. The percentage of light a surface reflects is called the reflectance (or albedo) of the surface. The phe nomenal counterpart of reflectance is called light ness. The simplest and most obvious determinant of lightness would seem to be the absolute amount of light (luminance) reflected by a surface, as measured by the eye. This account immediately fails because the amount (as opposed to percentage) of light a surface reflects is determined as much by the amount of light striking the surface as by the reflectance of the surface. The remarkable fact is that we perceive surface reflectance with rough accuracy despite wide variations in illumination. These facts produce what has been called the constancy question, that is, how the apparent lightness of surfaces remains so con stant when variations in the amount of illumination create great variations in the absolute amount of light that these surfaces reflect. An additional question, made relevant by theoretical differences, concerns what role, if any, processes of depth perception play in lightness constancy. Consider how the major theo ries of lightness perception answer these questions. For many years, the conventional explanation of lightness constancy was that of Helmholtz (1867/1962), who maintained that the level of illumination is un consciously taken into account in evaluating the in tensity of the reflected light. Such a theory makes intuitive sense since we do seem to be aware of dif ferent levels of illumination, both over time and within
TL;DR: New values for lipid, water, and caloric contents of eggs of precocial, semiprecocial, semi-altricial, and altricial species are reported to provide an overview of the variation among these values as a function of embryonic maturity at hatching.
Abstract: -The contents of fresh eggs of altricial, semi-altricial, semi-precocial, and precocial birds were compared with values for yolk content gathered from the literature. The continuum of developmental maturity at hatching from altricial to precocial eggs is correlated with an increase in yolk, solids, and caloric contents (per gram wet mass) and a decrease in water content. The proportion of lipid in dry matter and caloric content per gram dry mass does not vary significantly among the four developmental groups. The progressively higher caloric content on a wet mass basis with increasing precocity is a result of a larger solid content and lower water content, rather than variation in caloric value of the dry matter itself. Comparison of values within the same developmental group discloses no significant correlation between relative yolk content and egg mass. The total amount of calories in eggs is more importantly determined by egg mass than by yolk content. A freshly laid avian egg contains the necessary nutrients and raw materials that will eventually produce a hatchling. Although it has been recognized since the study of Tarchanoff (1884) that the initial proportions of yolk and albumen differ considerably in the eggs of altricial and precocial birds, the relations between the energetic and chemical contents of eggs and developmental mode are not completely understood (see Ricklefs 1974, Kendeigh et al. 1977, for review). We report here new values for lipid, water, and caloric contents of eggs of precocial, semiprecocial, semi-altricial, and altricial species. These results are combined with previously published caloric and yolk contents to provide an overview of the variation among these values as a function of embryonic maturity at hatching.
TL;DR: In situ measurements of this seepage flow have been made along four offshore transects in the Bay as discussed by the authors, showing that the flow rate decreases rapidly offshore; within 30 m of the shoreline, the submarine outflow rates were typically 40 l (day m 2 ) −1 and decreased to less than 10 l(daym 2 )−1 at a distance of 100 m from shore.
TL;DR: Genomic Southern blotting analysis reveals that a 5' flanking DNA sequence located 1.5-2.0 kb upstream from the C mu and C alpha genes undergoes extensive length variation in the germlines of inbred and wild mice, suggesting that both phenomena are reflections of intrinsic genetic properties of these Ig gene 5'Flanking sequences.
TL;DR: Experimentally damaged leaves of Cucurbita moschata mobilize substances to the damaged region within 40 minutes, which stimulate feeding by Acalymma vittata and inhibit feeding by Epilacha tredecimnotata.
Abstract: Experimentally damaged leaves of Cucurbita moschata mobilize substances to the damaged region within 40 minutes. These substances stimulate feeding by Acalymma vittata (Coleoptera: Chrysomelidae) and inhibit feeding by Epilacha tredecimnotata (Coleoptera: Coccinelidae). Under natural conditions, Epilachna cuts a circular trench in the leaf before feeding on the encircled leaf material, thus preventing mobilization of the deterrent substances to the feeding area.
TL;DR: In this article, the Poynting-Robertson effect was introduced to render the Lagrangian points unstable on a time scale that is long compared to the period of rotation of the two massive bodies.
Abstract: The force of radiation pressure is included in the restricted three-body problem by considering the major radial components of the pressure force for the case of a particle in the vicinity of two luminous massive bodies, as well as by introducing the Poynting-Robertson effect for the case of one luminous body. The positions of the Lagrangian points L4 and L5 are found as functions of the ratio of radiation to gravitational forces. The Poynting-Robertson effect renders the L4 and L5 points unstable on a time scale that is long compared to the period of rotation of the two massive bodies. Implications for space colonization and a mechanism for producing azimuthal asymmetries in the interplanetary dust complex are discussed.
TL;DR: In this paper, a total of 77 treatment cycles of human menopausal gonadotropin (hMG)-human chorionic gonadotropic (hCG) were administered to 41 infertile patients with polycystic ovarian disease who failed to conceive on clomiphene.
TL;DR: The findings are interpreted as consistent with the hypothesis that a strong need for Power, if it is inhibited and stressed, leads to chronic sympathetic overactivity which has an immunosuppressive effect making individuals characterized by this syndrome more susceptible to illness.
Abstract: Previous research has reported that individuals high in the need for Power, high in inhibition, and high in power stress (the HHH group) are more likely than other individuals to report more severe illnesses. The present study investigates the possibility that the mechanism underlying this relationship is greater sympathetic activation in the HHH group which has an immunosuppressive effect. College males with the HHH syndrome reported more frequent and more severe illnesses than other individuals, as in previous studies. More of the HHH than other subjects also showed above average epinephrine excretion rates in urine and below average concentrations of immunoglobulin A in saliva (S-IgA). Furthermore, higher rates of epinephrine excretion were significantly associated with lower S-IgA concentrations, and lower S-IgA concentrations were significantly associated with reports of more frequent illnesses. The findings are interpreted as consistent with the hypothesis that a strong need for Power, if it is inhibited and stressed, leads to chronic sympathetic overactivity which has an immunosuppressive effect making individuals characterized by this syndrome more susceptible to illness.
TL;DR: Multiphoton ionization (MPI) is rapidly evolving into a valuable adjunct to VUV spectroscopy for the study of the highly excited states of molecules as mentioned in this paper, and several examples are given of its applications.
Abstract: Multiphoton ionization (MPI) spectroscopy is rapidly evolving into a valuable adjunct to VUV spectroscopy for the study of the highly excited states of molecules. The technique is described, and several examples are given of its applications. Studies of the 3pz Rydberg states of the methylbenzenes and of the 1B2u state of benzene show that state assignments can be made and new multiphoton structure seen that is not available in one-photon spectra. MPI of benzene in a supersonic jet demonstrates dramatic resolution improvement and shows that natural linewidth information can be gained for large molecules. Collisional effects in MPI spectra are briefly discussed with reference to Xe and to laser enhanced collisional broadening of nitric oxide in the supersonic beam.
TL;DR: Data suggest the existence of a specific immune response gene for Ro close to the D region of the major histocompatibility complex in patients with systemic lupus erythematosus.
Abstract: A search for anti-Ro or anti-nRNP antibodies by precipitin analysis among a population of 64 patients with systemic lupus erythematosus (SLE) or mixed connective tissue disease was undertaken. The 25% of SLE patients with anti-Ro did not have any distinct clinical features, compared to patients without anti-Ro or to anti-nRNP patients with SLE or mixed connective tissue disease. However, these patients did have a significantly greater frequency of rheumatoid factor (80%). Most importantly however, patients with anti-Ro had a significantly increased frequency of HLA-B8 (81%) and HLA-DRw3 (100%) compared to patients with anti-nRNP (B8--29%; DRw3--33%) or SLE patients without such antibodies (B8--41%; DRw3--25%). These data suggest the existence of a specific immune response gene for Ro close to the D region of the major histocompatibility complex.
TL;DR: The first phase of the study as mentioned in this paper obtained intimacy-scaled ratings from 100 subjects to 62 relationship terms and more than 1,000 subjects ranging in age from 12 to 90 from eight locations across the United States responded to the six relationship words selected (lover, best friend, friend, pal, colleague, acquaintance).
Abstract: Individuals use a variety of terms to designate the nature of their relationships with others, e.g., friend, lover, pal, etc. Although expectations for certain types of communicative behavior surely accompany the use of these terms, it was not clear what their communicative referents were. The first phase of this study obtained intimacy‐scaled ratings from 100 subjects to 62 relationship terms. Then more than 1,000 subjects ranging in age from 12 to 90 from eight locations across the United States responded to the six relationship words selected (lover, best friend, friend, pal, colleague, acquaintance) in terms of associated communicative behavior. The three factors central to these responses (personalness, synchrony, difficulty) were then used to analyze the relationship terms varied according to the gender, age, and marital status of the subject and the composition of a relationship to a specific other by gender. Among other findings: All age groups perceived increases in both personalized and synchron...
TL;DR: Activity in dorsal giant interneurons of the cockroach initiates flight movements if leg contact with a substrate is prevented, and the same interneuron initiate activity associated with running when leg contact is maintained.
Abstract: Activity in dorsal giant interneurons of the cockroach initiates flight movements if leg contact with a substrate is prevented. The same interneurons initiate activity associated with running when leg contact is maintained. Thus, which one of two completely different behaviors the giant interneurons evoke depends on the presence or absence of leg contact.
01 Jan 1980
TL;DR: The relationships between locomotor and postural behaviour on the one hand, and basic aspects of these animals’ biology, such as gross diet and use of forest structure on the other, are understood.
Abstract: Apart from marsupials and edentates, there is no order of mammals, living or fossil, which displays a greater diversity of locomotor and postural adaptations than extant primates. With body weight varying from about 100 grams to 200 kilograms, the Order Primates includes leapers, climbers, brachiators, knuckle-walkers and a variety of arboreal and terrestrial quadrupeds. Despite the interest which primate positional behaviour has engendered in anatomists, anthropologists and zoologists throughout this century, we still understand very little about the relationships between locomotor and postural behaviour on the one hand, and basic aspects of these animals’ biology, such as gross diet and use of forest structure on the other.
01 Nov 1980
TL;DR: In this paper, the stability of thin (100 nm) symmetrical and unsymmetrical membranes, assimilated with viscous liquids, to short and long wavelength perturbations is investigated.
Abstract: The stability of thin (< 100 nm) symmetrical and unsymmetrical membranes, assimilated with viscous liquids, to short and long wavelength perturbations is investigated. The asymmetry is due to the two different viscous phases surrounding the membrane and to the different interfacial tensions on the two faces of the membrane. The cell membrane is a case for which the present treatment is of significance. The dynamics of the membrane to perturbations is described by the Navier-Stokes equation modified with a body force which accounts for the fact that the range of the interaction forces is larger than the thickness of the film. The body force is computed assuming pair-wise additivity and accounting for the deformation of the interface produced by the perturbation. General dispersion equations are derived, and these equations describe the squeezing and stretching modes of perturbations. The growth coefficient is expressed as a function of the wavelength for various ratios of the viscosities of the two surrounding phases and various values of the two interfacial tensions. In the limiting cases of interfacial tension ratio equal to unity and wavelength large compared to the thickness of the film results of the previous investigators are obtained. For the symmetrical case expressions are derived for the critical and dominant wavelength of the squeezing and stretching modes. An application of the results to a cell membrane shows that the growth of the instability is dominated in this case by the stretching mode since the time scale of growth of the perturbations is four orders of magnitude less than that in the squeezing mode. For unsymmetrical systems the effect of differences between the interfacial tensions on the two faces on the ratio of the amplitudes of perturbations on the two faces is investigated. The results show in what manner differences in interfacial tension convey amplified or damped messages across the membrane.