Showing papers on "Population published in 1970"

Assessment of older people: self-maintaining and instrumental activities of daily living

Abstract: THE use of formal devices for assessing function is becoming standard in agencies serving the elderly In the Gerontological Society's recent contract study on functional assessment (Howell, 1968), a large assortment of rating scales, checklists, and other techniques in use in applied settings was easily assembled The present state of the trade seems to be one in which each investigator or practitioner feels an inner compusion to make his own scale and to cry that other existent scales cannot possibly fit his own setting The authors join this company in presenting two scales first standardized on their own population (Lawton, 1969) They take some comfort, however, in the fact that one scale, the Physical Self-Maintenance Scale (PSMS), is largely a scale developed and used by other investigators (Lowenthal, 1964), which was adapted for use in our own institution The second of the scales, the Instrumental Activities of Daily Living Scale (IADL), taps a level of functioning heretofore inadequately represented in attempts to assess everyday functional competence Both of the scales have been tested further for their usefulness in a variety of types of institutions and other facilities serving community-resident older people Before describing in detail the behavior measured by these two scales, we shall briefly describe the schema of competence into which these behaviors fit (Lawton, 1969) Human behavior is viewed as varying in the degree of complexity required for functioning in a variety of tasks The lowest level is called life maintenance, followed by the successively more complex levels of func-

Epidemiology: Principles and Methods

Abstract: The purpose of this book is to introduce the principles and methods of epidemiology defined as the study of the distribution and determinants of disease frequency in man Since epidemiology has the practical purpose of discovering relations which offer possibilities for disease prevention the search for causal associations is predominant in epidemiology The strategy of an epidemiological study includes the assembly of all the facts the forming and testing of hypotheses and the choice of the type of study (case-control cohort prospective retrospective cross-sectional or longitudinal study) Disease classification is an essential procedure and it includes 2 components: 1) the grouping of ill persons into categories such that the characteristics of the members of 1 category permit them to be distinguished from the members of another and 2) the arrangement of the disease entities themselves into groups having common characteristics Measures of disease frequency are incidence attack rate and prevalence; sources of data are vital records and morbidity surveys Characteristics of the people include age sex race religion marital status migration status occupation and socioeconomic status Variations in the frequency of different disease manifestations from place to place are of paramount importance as are the changes associated with the passage of time Awareness of the interactions between person place and time in the causation of disease is extremely important at all times Cohort studies are especially important; the group or groups to be studied are defined in terms of characteristics manifest prior to the appearance of the disease and are observed over a period of time to determine the frequency of the disease Case-control studies inquire which groups of individuals have or have not the disease which is under investigation; intervention studies are those designed and carried out specifically as studies of procedures or programs considered to have possibilities for disease prevention Human genetics and epidemiology interact continually as for example in the study of environmental disease or of familial disease

The units of selection

Abstract: The principle of natural selection as the motive force for evolution was framed by Darwin in terms of a "struggle for existence" on the part of organisms living in a finite and risky environment. The logical skeleton of his argument, however, turns out to be a powerful predictive system for changes at all levels of biological organization. As seen by present-day evo­ lutionists, Darwin's scheme embodies three principles (Lewontin 1) : 1. Different individuals in a popUlation have different morphologies, physiologies, and behaviors (phenotypic variation). 2. Different phenotypes have different rates of survival and reproduc­ tion in different environments (differential fitness). 3. There is a correlation between parents and offspring in the contribu­ tion of each to future generations (fitness is heritable). These three principles embody the principle of evolution by natural selec­ tion. While they hold, a population will undergo evolutionary change. It is important to note a certain generality in the principles. No particular mechanism of inheritance is specifi'ed, but only a correlation in fitness between parent and offspring. The population would evolve whether the correlation between parent and offspring arose from Mendelian, cytoplasmic, or cultural inheritance. Conversely, when a population is at equilibrium under selection (for example, a stable polymorphism due to heterozygous superiority), there is no correlation in fitness between parent and offspring, no matter what the mechanism of inheritance. Nor does Principle 2 specify the reason for the differential rate of contribution to future generations of the different phenotypes. It is not necessary, for example, that resources be in short supply for organisms to struggle for existence. Darwin himself pointed out that "a plant at the edge of a desert is said to struggle for life against the drought." Thus, although Darwin came to the idea of natural selection from consideration of Malthus', essay on overpopulation, the element of competition between organisms for a resource in short supply is not integral to the argument. Natural selection occurs even when two bacterial strains are growing logarithmically in an excess of nutrient broth if they have different division times. The generality of the principles of natural selection means that any enti­ ties in nature that have variation, reproduction, and heritability may evolve. For example, if we replace the term individual with the term population and

A generalized Kruskal-Wallis test for comparing K samples subject to unequal patterns of censorship

Abstract: SUMMARY A generalization of the Kruskal-Wallis test, which extends Gehan's generalization of Wilcoxon's test, is proposed for testing the equality of K continuous distribution functions when observations are subject to arbitrary right censorship. The distribution of the censoring variables is allowed to differ for different populations. An alternative statistic is proposed for use when the censoring distributions may be assumed equal. These statistics have asymptotic chi-squared distributions under their respective null hypotheses, whether the censoring variables are regarded as random or as fixed numbers. Asymptotic power and efficiency calculations are made and numerical examples provided. A generalization of Wilcoxon's statistic for comparing two populations has been proposed by Gehan (1965a) for use when the observations are subject to arbitrary right censorship. Mantel (1967), as well as Gehan (1965b), has considered a further generalization to the case of arbitrarily restricted observation, or left and right censorship. Both of these authors base their calculations on the permutation distribution of the statistic, conditional on the observed censoring pattern for the combined sample. However, this model is inapplicable when there are differences in the distribution of the censoring variables for the two populations. For instance, in medical follow-up studies, where Gehan's procedure has so far found its widest application, this would happen if the two populations had been under study for different lengths of time. This paper extends Gehan's procedure for right censored observations to the comparison of K populations. The probability distributions of the relevant statistics are here considered in a large sample framework under two models: Model I, corresponding to random or unconditional censorship; and Model II, which considers the observed censoring times as fixed numbers. Since the distributions of the censoring variables are allowed to vary with the population, Gehan's procedure is also extended to the case of unequal censorship. For Model I these distributions are theoretical distributions; for Model II they are empirical. Besides providing chi-squared statistics for use in testing the hypothesis of equality of the K populations against general alternatives, the paper shows how single degrees of freedom may be partitioned for use in discriminating specific alternative hypotheses. Several investigators (Efron, 1967) have pointed out that Gehan's test is not the most efficient against certain parametric alternatives and have proposed modifications to increase its power. Asymptotic power and efficiency calculations made below demonstrate that their criticisms would apply equally well to the test proposed here. Hopefully some of the modifications they suggest can likewise eventually be generalized to the case of K

An analysis of the sequences of the variable regions of bence jones proteins and myeloma light chains and their implications for antibody complementarity

Abstract: In an attempt to account for antibody specificity and complementarity in terms of structure, human kappa-, human lambda-, and mouse kappa-Bence Jones proteins and light chains are considered as a single population and the variable and constant regions are compared using the sequence data available. Statistical criteria are used in evaluating each position in the sequence as to whether it is essentially invariant or group-specific, subgroup-specific, species-specific, etc. Examination of the invariant residues of the variable and constant regions confirms the existence of a large number of invariant glycines, no invariant valine, lysine, and histidine, and only one invariant leucine and alanine in the variable region, as compared with the absence of invariant glycines and presence of three each of invariant alanine, leucine, and valine and two each of invariant lysine and histidine in the constant region. The unique role of glycine in the variable region is emphasized. Hydrophobicity of the invariant residues of the two regions is also evaluated. A parameter termed variability is defined and plotted against the position for the 107 residues of the variable region. Three stretches of unusually high variability are noted at residues 24-34, 50-56, and 89-97; variations in length have been found in the first and third of these. It is hypothesized that positions 24-34 and 89-97 contain the complementarity-determining residues of the light chain-those which make contact with the antigenic determinant. The heavy chain also has been reported to have a similar region of very high variability which would also participate in forming the antibody-combining site. It is postulated that the information for site complementarity is contained in some extrachromosomal DNA such as an episome and is incorporated by insertion into the DNA of the structural genes for the variable region of short linear sequences of nucleotides. The advantages and disadvantages of this hypothesis are discussed.

A population of lymphocytes bearing a membrane receptor for antigen-antibody-complement complexes. I. Separation and characterization.

Abstract: A population of lymphoid cells from several animal species, including man, was identified through a membrane receptor which binds sheep red blood cells treated with antibody and complement. When cells from different lymphoid organs were incubated with EAC at 37°C, only part of the lymphocytes (named CRL) bound EAC and formed rosettes, and this interaction was shown to be C3-dependent. Mouse lymphoid cells could be specifically depleted of CRL by allowing them first to interact with EAC and then submitting the mixture to ultracentrifugation in a gradient of BSA. After ultracentrifugation, a population of cells containing 95% or more of non-CRL were recovered from the upper layers of the gradient. In addition to their different abilities to bind EAC, CRL and non-CRL from mouse lymphoid organs could be distinguished by the following properties: (a) CRL adhered preferentially to nylon wool at 37°C in the presence of mouse serum. (b) After differential flotation in a gradient of BSA, a significantly higher proportion of CRL were recovered from the upper layers of the gradient. (c) The population of CRL contained most of the lymphocytes bearing immunoglobulin determinants on their membranes. (d) The distribution of CRL was quite different among lymphocytes obtained from various lymphoid organs, and they were never found in the thymus. (e) The membrane receptor for EAC was not detected in plaque-forming cells of mice which had been previously immunized with burro red cells. CRL and non-CRL could not be distinguished by their life span, as they were found in similar proportions among long-lived and short-lived lymphocytes from mouse peripheral lymph nodes. The function of this receptor on the membrane of certain lymphoid cells may be related to (a) the trapping and localization of antigen in lymphoid organs or (b) the localization of lymphoid cells in inflammatory sites.

Smoking and health.

Abstract: A new development in the 20th century has been the increasing use of cigarettes manufactured primarily from flue-cured tobaccos. It has been clearly shown during the last 20 years that cigarette smoking impairs health to such a serious degree that means for its control must be developed. Cigarette smoking has been found to have a major part in the development of many diseases the most important of which are ischemic heart disease lung cancer chronic bronchitis and emphysema. Apart from these diseases which are major causes of death cigarette smoking is responsible for widespread and distressing disability from chest and heart diseases and increases the mortality and disability from several other conditions. The more recent adoption of cigarette smoking by women in developed countries is already associated with increasing mortality and morbidity from lung cancer and other illnesses. The health effects of smoking are largely confined to the individual smoker and although severe become manifest only after many years of smoking and are therefore not obviously connected with the habit. In countries where deaths and disability associated with cigarette smoking are already at high levels more preventive action is necessary. It is essential to take action that will promote the reduction or discontinuance of smoking and that will discourage young people from starting to smoke. Focus in the remainder of the discussion is on evidence connecting smoking with disease smoking habits and total mortality diseases causing excess mortality of cigarette smokers cigarette smoking as a cause of excess mortality cigarette smoking as a cause of excess morbidity specific diseases related to cigarette smoking approaches to prevention and experience in the United States.

Age at first birth and breast cancer risk.

Abstract: An international collaborative study of breast cancer and reproductive experience has been carried out in 7 areas of the world. In all areas studied, a striking relation between age at first birth and breast cancer risk was observed. It is estimated that women having their first child when aged under 18 years have only about one-third the breast cancer risk of those whose first birth is delayed until the age of 35 years or more. Births after the first, even if they occur at an early age, have no, or very little, protective effect. The reduced risk of breast cancer in women having their first child at an early age explains the previously observed inverse relationship between total parity and breast cancer risk, since women having their first birth early tend to become ultimately of high parity. The association with age at first birth requires different kinds of etiological hypotheses from those that have been invoked in the past to explain the association between breast cancer risk and reproductive experience.

Cell interactions in the induction of tolerance: the role of thymic lymphocytes

Abstract: Thymectomized, lethally irradiated, bone marrow reconstituted mice were treated with a large dose of sheep red blood cells (SRBC) over the course of 30 days. They were unable to respond to further antigenic challenge for one month. Fifteen million thymocytes given 4 days after the termination of treatment restored their ability to respond. The same antigenic treatment given to similar chimeras, which differed only in having had 15 × 106 thymus cells added to the bone marrow inoculum, also abolished the response to further antigenic challenge. In contrast to chimeras without thymus cells present during the course of treatment, the later addition of thymocytes to these animals did not restore their response. It did, however, restore the response to a second challenge of antigen given 17 days after the addition of thymocytes. This response was the same as non-treated animals given only one injection of thymocytes and significantly less than non-treated animals given thymocytes twice. The following explanation of these results is offered. Bone marrow derived (BMD) lymphocytes that can make antibody without assistance of thymus derived (TD) lymphocytes were made tolerant in the absence of TD cells. Thymus dependent BMD cells were not. New cells, coming from the bone marrow, broke the tolerant state within a month. When TD cells were present both populations of BMD cells, as well as the TD cells, were made tolerant. New BMD cells regenerating from the bone marrow abrogated the tolerant state of the BMD population. This breaking of tolerance could only be seen in mice given additional thymocytes as the tolerance of the TD cells was not broken in the absence of a thymus. Thus, the induction of tolerance as well as the induction of immunity in thymus dependent BMD cell populations, seems to require the co-operation of TD cells.

A standardized psychiatric interview for use in community surveys.

Abstract: Surveys of psychiatric illness in the community are at present handicapped by the lack of valid and reliable methods of case-identification. The widely varying estimates of psychiatric prevalence made by different workers in this field (Lin and Standley, 1962) emphasize the urgent need for such tech niques, which could be used both in field surveys and in the screening of general practice populations. In large-scale psychiatric surveys, the use of a two-stage screening procedure is desirable and may, indeed, be essential for economic reasons. The first stage entails the selection of possible or 'potential' cases by means of a rapid and simply administered screening test; the second comprises detailed clinical examination of such potential cases in order that they may be confirmed as actual cases (Blum, 1962) and given an accurate diagnostic assessment. The present paper is concerned only with the second of these stages, namely, the development of a standard ized psychiatric interview and rating technique suitable for application to potential cases in a com munity setting. A number of standardized psychiatric interviews, including some which are highly reliable, have been developed in recent years, but for various reasons all are unsuitable for field surveys. In the United States, Lorr, Klett, and McNair (1963) have de scribed an assessment based on the Inpatient Multi dimensional Psychiatric Scale (IMPS), and Overall and Gorham (1962) have used a psychiatric assess ment derived from a shortened version of the Lorr scale; both these scales heavily emphasize psychotic phenomena which are relatively uncommon in the general population. The interview described by Spitzer, Fleiss, Burdock, and Hardesty (1964), although in some ways more suitable, is still in sufficiently flexible and contains many items which would make it unacceptable to normal individuals. In this country, Wing, Birley, Cooper, Graham, and Isaacs (1967) and Kendell, Everitt, Cooper, Sar torius, and David (1968) have published accounts of the 'Present State Examination' which has been designed primarily for use in international studies. This very comprehensive 500-item schedule was designed for administration to known psychiatric patients and again does not readily lend itself in its present form for use in community surveys. With these considerations in mind, a standardized psychiatric interview has been constructed to meet the following requirements: (1) Psychiatric assessment should be made by an experienced psychiatrist in a realistic ciinical setting; (2) The interview should be acceptable to indi viduals who may not see themselves as psychiatrically disturbed; (3) The content of the interview should be appro priate to the types of psychiatric disturbance com monly encountered in the community; (4) The interview should generate information about individual symptoms and signs of illness as well as an overall diagnostic assessment;

The rapid intermixing of cell surface antigens after formation of mouse-human heterokaryons.

Abstract: Cells from established tissue culture lines of mouse ( cIID ) and human ( VA-2 ) origin were fused together with Sendai virus, producing heterokaryons bearing both mouse and human surface antigens which were then followed by the indirect fluorescent antibody method. Within 40 mm following fusion, total mixing of both parental antigens occurred in over 90% of the heterokaryons. Mouse H-2 (histocompatibility) and human surface antigens were visualized by successive treatment of the heterokaryons with a mixture of mouse alloantiserum and rabbit anti- VA-2 antiserum, followed by a mixture of fluorescein-labelled goat anti-mouse IgG and tetramethyl-rhodamine-labelled goat anti-rabbit IgG(Fc). The cIID x VA-2 fusions were carried Out in suspension and maintained at 37°C in a shaking water bath; aliquots were removed at various intervals and stained with the above reagents. The heterokaryon population was observed to change from an initial one (5-min post-fusion) of non-mosaics (unmixed cell surfaces of red and green fluorescence) to one of over 90% mosaics (total intermixing of the 2 fluorochromes) by 40 min after fusion. Mouse-human hybrid lines, derived from similar fusions, gave fluorescence patterns identical to those of the mosaic heterokaryons. Four possible mechanisms would yield such results: (i) a very rapid metabolic turnover of the antigens; (ii) integration of units into the membrane from a cytoplasmic precursor pool; (iii) movement, or ‘diffusion’of antigen in the plane of the membrane; or (iv) movement of existing antigen from one membrane site into the cytoplasm and its emergence at a new position on the membrane. In an effort to distinguish among these possibilities, the following inhibitor treatments were carried out: (1) both short- and long-term (6-h pre-treatment) inhibition of protein synthesis by puromycin, cycloheximide, and chloramphenicol; (2) short-term inhibition of ATP formation by dinitrophenol (DNP) and NaF; (3) short- and long-term inhibition of glutamine dependent pathways with the glutamine analogue 6-diazo-5-oxonorleucine; and (4) general metabolic suppression by lowered temperature. The only treatment found effective in preventing the mosaicism was lowered temperature, from which resulted a sigmoidal curve for per cent mosaics versus incubation temperature. These results would be consistent with mechanisms iii and/or iv but appear to rule out i and ii. From the speed with which the antigen markers can be seen to propagate across the cell membrane, and from the fact that the treatment of parent cells with a variety of metabolic inhibitors does not inhibit antigen spreading, it appears that the cell surface of heterokaryons is not a rigid structure, but is ‘fluid’ enough to allow free ‘diffusion’ of surface antigens resulting in their intermingling within minutes after the initiation of fusion.

Standards for Children's Height at Ages 2-9 Years Allowing for Height of Parents

Abstract: Charts are presented which give centile standards for boys9 and girls9 heights at ages 2 to 9 when parents9 height is allowed for. Mid-parent height is used (i.e. the average of father9s and mother9s height). A comparison is made with results from the existing `parent-unknown9 British standard charts. A child at the 3rd centile on the parent-unknown charts is (i) at the 20th centile on the new charts if his parents are small enough to average 3rd centile for adults, (ii) at about the 1st centile if his parents average the 97th centile. Conversely a child with 97th centile parents has only to be at the 25th centile for the population in the parent-unknown charts to be at the conventional 3rd centile limit of normal when parental height is allowed for. Thus the new standards result in considerably increased precision. Examples are given of normal boys with small parents who plotted outside the 3rd centile on the conventional charts but inside on the present charts. The differential diagnosis of genetic small stature is made considerably more straightforward by the use of these charts. The correlation coefficients are given at successive ages, from 1 month to 9 years, for child9s supine length or height with mid-parent height and for mother-daughter, mother-son, father-daughter, and father-son relationships.

Spacing Patterns in Mobile Animals

Abstract: The study of spacing patterns in animals is a field in which ecology and ethology complement each other. Spacing is brought about to a considerable degree by the manner in which different individuals of a species react to each other, and it has important effects on the population dynamics, popula­ tion genetics, and evolution of species. The dispersion of animals in space and time results, in a proximate sense, from the direct response of individu­ als to features of the environment and to the presence or absence of other individuals of the species. This review will examine concepts of spacing patterns in mobile animals from the perspective of their proximate causes, their ecological consequences, and their adaptive significance.

Suicide and Primary Affective Disorders

Abstract: Primary affective disorders, depressive or manic episodes in patients who have been psychiatrically well previously, or who have had episodes of mania or depression without other psychiatric illnesses (Robins and Guze, 1969), are associated with high suicide rates. The following data indicate that the suicide risk among these patients is over thirty times greater than that of the population without these disorders, and that the risk of suicide compared to other causes of death may be increased early in the course of the illness.

Polymorphism in the Esterases of Atlantic Herring

Abstract: The esterase enzymes of the tissues of Atlantic herring (Clupea harengus harengus) were analyzed by starch gel electrophoresis. Four sets of esterase bands were distinguished by their electrophoretic mobility, their relative activity with the two substrates, alpha-naphthyl acetate and alpha-naphthyl butyrate, and their relative concentrations in plasma, liver, and heart tissues. All of the esterases were inhibited by 10−4M solutions of dichlorvos, an organophosphate inhibitor, but none was inhibited by 10−4M eserine sulfate or by 10−4 M EDTA. Polymorphism was noted in all four sets of esterases. Evidence for the genetic control of the fastest migrating set was obtained from population genetic analyses. In this set of esterases, five distinct bands occurred either singly or in pairs. The observed distribution of the three most common bands fits the hypothesis that they are controlled by a set of autosomal alleles. The two rarest bands occurred only in the heterozygous state, as would be expected. ...

Industrialization and Social Stratification

Abstract: This paper reviews the current state of knowledge about the effects of industrialization upon systems of social stratification. Taking societies as the unit of observation, we consider the relationships between level of industrialization and (1) the distribution of status characteristics in the population (the structure of stratification); (2) the pattern of interrelations among status characteristics (the process of stratification); and (3) the form of linkages between status characteristics and other aspects of social behavior (the consequences of stratification). A set of propositions is specified, a few of which are empirically well established but most of which yet require empirical testing.

Does differential adhesion govern self‐assembly processes in histogenesis? Equilibrium configurations and the emergence of a hierarchy among populations of embryonic cells

Abstract: The differential adhesion hypothesis attributes sorting-out behavior of embryonic cells to differences in the strengths of their intercellular adhesions. It suggests that cells in mixed populations rearrange themselves to minimize their total adhesive free energy. The final configuration adopted is viewed as approaching a moststable or equilibrium configuration, with the less cohesive cell/population tending to envelop the more cohesive one. The hypothesis enables two predictions to be made. First, if the final configuration adopted by a mixed cell population indeed approximates an equilibrium configuration, the same final configuration should be approached irrespective of the starting configuration. Second, comparison of the equilibrium configurations for all possible pair-combinations of a series of cell populations of different types should reveal a hierarchy of “preference” for the internal position, reflecting a hierarchy of cellular cohesiveness. These predictions have been tested and confirmed. First, any particular pair of tissues approaches the same final configuration, irrepective of whether the cells are initially randomly intermixed or tissue fragments are laterally joined. Second, the predicted hierarchy of preference for the internal position has been found, consistent with a hierarchy of cellular cohesiveness. An effort has been made to clarify confusions that have arisen concerning the differential adhesion hypothesis. It is particularly stressed that the hypothesis offers an explanation for cell population behavior in terms of relative strengths of cell adhesions and makes no proposals concernnig the chemistry of adhesion. However, the value of equilibrium configurations in guiding biochemical investigations of cell surface adhesives is pointed out, as is the relevance of the present observations to natural morphogenetic events.

Thromboembolic Disease and the Steroidal Content of Oral Contraceptives. A Report to the Committee on Safety of Drugs

Abstract: Reports of thromboembolism following the use of oral contraceptives received by drug safety committees in the United Kingdom, Sweden, and Denmark have been analysed to investigate possible differences in the risks associated with the various preparations. For this purpose the numbers of reports of thromboembolism attributed to each product were compared with the distribution that would have been expected from market research estimates of sales, assuming that all products carried the same risk. A positive correlation was found between the dose of oestrogen and the risk of pulmonary embolism, deep vein thrombosis, cerebral thrombosis, and coronary thrombosis in the United Kingdom. A similar association was found for venous thrombosis and pulmonary embolism in Sweden and Denmark. No significant differences could be detected between sequential and combined preparations containing the same doses of oestrogen, nor between the two oestrogens, ethinyloestradiol and mestranol. Certain discrepancies in the data suggest that the dose of oestrogen may not be the only factor related to the risk of thromboembolism; thus there was a significant deficit of reports associated with the combination of mestranol 100 μg. with norethynodrel 2·5 mg. and a significant excess of reports associated with the combination of ethinyloestradiol 50 μg. with megestrol acetate 4 mg. An excess of reports also occurred with other combined preparations containing megestrol acetate. The data obtained in earlier epidemiological studies were re-examined and, though no trend was obvious in any one of them, the combined results showed an excess of cases of thromboembolism at the highest dose of oestrogen. The finding of a positive correlation between the dose of oestrogen and the risk of coronary thrombosis is of special interest since previous studies have failed to provide clear evidence of a relationship between oral contraceptives and this condition.

Populations, Species, and Evolution: An Abridgment of Animal Species and Evolution

Abstract: 1. Evolutionary Biology 2. Species Concepts and Their Application 3. Morphological Species Characters and Sibling Species 4. Biological Properties of Species 5. Isolating Mechanisms 6. The Breakdown of Isolating Mechanisms (Hybridization) 7. The Population, Its Variation and Genetics 8. Factors Reducing the Genetic Variation of Populations 9. Storage and Protection of Genetic Variation 10. The Unity of the Genotype 11. Geographic Variation 12. The Polytypic Species of the Taxonomist 13. The Population Structure of Species 14. Kinds of Species 15. Multiplication of Species 16. Geographic Speciation 17. The Genetics of Speciation 18. The Ecology of Speciation 19. Species and Transpecific Evolution 20. Man as a Biological Species Glossary Bibliography Index

Definition of a Continuous Human Cell Line Derived from Neuroblastoma

Abstract: Summary A continuous hyperdiploid human cell line, IMR-32, was derived from neuroblastoma tissue. At least two morphologically distinct cell types comprise the population of IMR-32. These two cell types have the same characteristic chromosomal constitution and hyperdiploid stem line number, indicating a common clonal origin. One of the cell types, generally rarely observed because it occurs in minute numbers, appears to differentiate from the major or predominating cell. Marked ultrastructural differences were noted between the 2 cell types. The cell line proved a relatively poor host for virus replication, particularly for representative viruses of two of the human enterovirus groups. The electrophoretically more mobile lactic dehydrogenase isozymes of IMR-32 were retained after extended subcultivation.

The study of language in its social context

Abstract: The work which is reported in this study is an investigation of language within the social context of the community in which it is spoken It is a study of a linguistic structure which is unusually complex, but no more so than the social structure of the city in which it functionsWithin the linguistic structure, change has occurred on a large scale, and at a rapid pace which is even more characteristic of the changing structure of the city itself Variability is an integral part of the linguistic system, and no less a part of the behavior of the city To assess the relative complexity of the linguistic problem presented by New York City, it may be useful to compare this investigation to an earlier study of a sound change in progress that I carried out on the island of Martha's Vineyard (Labov 1963) This earlier work traced the distribution of a particular sound feature as it varied through several occupational, ethnic, and geographic sub-groups of the population, and through three generations of native islanders The objective pattern of language behavior was seen to be correlated with the overall social pattern of differential reaction to specific economic strains and social pressures; it was then possible to assign a single social meaning to the linguistic feature in question It was thus demonstrated that social pressures are continually acting upon the structure of a language, as it develops through the mechanism of imitation and hypercorrection

A Predator-Prey System in the Marine Intertidal Region. I. Balanus glandula and Several Predatory Species of Thais

Abstract: On San Juan Island, Washington, three species of intertidal barnacles (Balanus glandula, Balanus cariosus and Chthamalus fissus) are the main prey of several species of predators, the commonest being three species of snails, Thais emarginata, Thais canaliculata and Thais lamellosa. Larvae of B. glandula settle throughout the intertidal zone but, except in quiet bays, survive to maturity only in a narrow zone at the top of the shore. In quiet bays, where predators of barnacles were scarce, and in areas of turbulent water where predators were excluded by other circumstances, adult B. glandula occurred over the whole intertidal zone. From the lower part of the intertidal zone. Predators were evidently eliminating all B. glandula from the lower part of the intertidal zone. The rates of feeding of Thais lamellosa and Thais emarginata were measured in cages on the shore. The existing population of Thais could account for all of the mortality of B. glandula which occurred at low shore levels in mid and late summer. By late autumn these predators could eat all the remaining B. glandula of that year's settlement at low levels, but at upper shore levels the Thais population could not account for all the mortality of B. glandula in summer. The Thais populations shift upwards from the lower shore levels in the autumn and it is very probable that this increased predation is enough to eliminate the barnacles at the middle and upper shore within the next year. The recruitment of B. glandula every year was quite regular. The breeding population in the narrow "refuge" zone at the top of the intertidal zone was capable of replacing itself as well as colonizing the middle and lower shore. The settlement below the refuge zone can be regarded simply as a regular food supply for the predator population. Because of the dependability of this food supply at upper shore levels, a predator, T. emarginata, has evolved to specialize at these upper levels. In Scotland, where the recruitment of barnacles is irregular, no such specialization is possible. Thus at least two species of predators are supported at different shore levels at San Juan Island, whereas only one species occupies the whole intertidal shore in Scotland. In Scotland, much of the mortality of young barnacles was caused by intraspecific crowding in dense populations, and these deaths provide food for scavengers, rather than predators. In contrast, at San Juan Island of the mortality of young barnacles is caused by predators. Thus the predators at San Juan Island are more efficient than those in Scotland, since they eat a much higher proportion of the available prey. Whereas in Scotland the distribution and abundance of barnacles is largely determined by competition for space, at San Juan Island the barnacles is largely determined by competition for space, at San Juan Island the barnacles are limited by predation.

Temperature Dependence of Raman Scattering in Silicon

Abstract: We have measured the linewidth and the frequency of the q=0 optical phonon in silicon over the temperature range of 20-770\ifmmode^\circ\else\textdegree\fi{}K. The temperature dependence of the linewidth has been interpreted as arising from the decay of the optical phonon to two LA phonons at half the optical frequency. From the observed temperature variation, we deduce an absolute half-width $\ensuremath{\Gamma}$ of 2.1 ${\mathrm{cm}}^{\ensuremath{-}1}$ at 0\ifmmode^\circ\else\textdegree\fi{}K. This value is considerably smaller than that obtained theoretically by Cowley on the basis of numerical calculations which include decay to phonons throughout the Brillouin zone. His numerical calculations also predict a temperature dependence of the linewidth which does not agree with experiment. However, the observed change in frequency with temperature correlates very well with Cowley's theory. We have also studied the relative intensities of Stokes and anti-Stokes components of Raman spectra. The observed temperature dependence of the relative intensities is compared with that predicted on the basis of the Bose-Einstein population factor for the optical phonon.

Tearoom Trade: Impersonal Sex in Public Places

Abstract: From the time of its first publication, Tearoom Trade engendered controversy. It was also accorded an unusual amount of praise for a first book on a marginal, intentionally self-effacing population by a previously unknown sociologist. The book was quickly recognized as an important, imaginative, and useful contribution to our understanding of "deviant" sexual activity. Describing impersonal, anonymous sexual encounters in public restrooms - "tearooms" in the argot - the book explored the behaviour of men whose closet homosexuality was kept from their families and neighbours. By posing as an initiate, the author was able to engage in systematic observation of homosexual acts in public settings, and later to develop a more complete picture of those involved by interviewing them in their homes, again without revealing their unwitting participation in his study. This enlarged edition of Tearoom Trade includes the original text, together with a retrospect, written by Nicholas von Hoffman, Irving Louis Horowitz, Lee Rainwater, Donald P. Warwick, and Myron Glazer. The material added includes a perspective on the social scientist at work and the ethical problems to which that work may give rise, along with debate by the book's initial critics and proponents. Humphreys added a postscript and his views on the opinion expressed in the retrospect.

Lassa fever, a new virus disease of man from West Africa. I. Clinical description and pathological findings.

Abstract: Lassa Fever, a hitherto unknown virus disease from Nigeria, caused the death of two missionary-nurses and the grave illness of a third. The onset is gradual with fever, weakness, myositis and ulcerative pharyngitis, progressing to symptoms of myocarditis, pneumonitis and pleuritis, encephalopathy, and evidences of a hemorrhagic diathesis. It is characterized in the early stages by moderate leukopenia, with increase of immature neutrophilic elements. It may be transmitted directly from person to person; the incubation period is about a week. It is likely to be of increasing public-health importance as travel to the interior parts of Nigeria increases, and as the area is developed because of future population pressures.