Showing papers on "Population published in 1980"

Principles of population genetics

Abstract: Genetic and Phenotypic Variation.- Organisation of Genetic Variation.- Random Genetic Drift.- Mutation and the Neutral Theory.- Darwinian Selection.- Inbreeding, Population Subdivision, and Migration.- Molecular Population Genetics.- Evolutionary Quantitative Genetics.- Population Genomics.- Human Population Genetics.

Aging, natural death, and the compression of morbidity.

Abstract: The average length of life has risen from 47 to 73 years in this century, but the maximum life span has not increased Therefore, survival curves have assumed an ever more rectangular form Eighty per cent of the years of life lost to nontraumatic, premature death have been eliminated, and most premature deaths are now due to the chronic diseases of the later years Present data allow calculation of the ideal average life span, approximately 85 years Chronic illness may presumably be postponed by changes in life style, and it has been shown that the physiologic and psychologic markers of aging may be modified Thus, the average age at first infirmity can be raised, thereby making the morbidity curve more rectangular Extension of adult vigor far into a fixed life span compresses the period of senescence near the end of life Health-research strategies to improve the quality of life require careful study of the variability of the phenomena of aging and how they may be modified

Randomized comparisons of radiotherapy and nitrosoureas for the treatment of malignant glioma after surgery.

Abstract: Within three weeks of definitive surgical intervention, 467 patients with histologically proved malignant glioma were randomized to receive one of four treatment regimens: semustine (MeCCNU), radiotherapy, carmustine (BCNU) plus radiotherapy, or semustine plus radiotherapy. We analyzed the data for the total randomized population and for the 358 patients in whom the initial protocol specifications were met (the valid study group). Observed toxicity included acceptable skin reactions secondary to radiotherapy and reversible leukopenia and thrombocytopenia due to chemotherapy. Radiotherapy used alone or in combination with a nitrosourea significantly improved survival in comparison with semustine alone. The group receiving carmustine plus radiotherapy had the best survival, but the difference in survival between the groups receiving carmustine plus radiotherapy and semustine plus radiotherapy was not statistically significant. The combination of carmustine plus radiotherapy produced a modest benefi...

Discrete stages of human intrathymic differentiation: Analysis of normal thymocytes and leukemic lymphoblasts of T-cell lineage

Abstract: A series of monoclonal antibodies was used to define three discrete stages of human intrathymic T-cell differentiation The earliest stage was confined to <10% of thymocytes, which were·reactive with both OKT9 and OKT10 Subsequently, approximately 70% of human thymocytes acquired a thymocyte-restricted antigen, OKT6, lost OKT9 antigen, and expressed reactivity with OKT4 and OKT5 These last two monoclonal antibodies were previously shown to define inducer (helper) and cytotoxic/suppressor populations, respectively, in peripheral blood The OKT4+, OKT5+, OKT6+ “common” thymocyte population represents the majority of thymocytes and accounts for more than 70% of thymocytes With further maturation, thymocytes lose OKT6 reactivity, segregate into OKT4+ and OKT5+ subsets, and acquire reactivity with OKT3 (and OKT1) This latter stage corresponds to the more functionally mature subset The possible relationship of acute lymphoblastic leukemia of T-cell lineage to these proposed stages of intrathymic differentiation was determined Analysis of 25 tumor populations showed that 21 could be related to one or another differentiative stage The majority (15/21) were derived from an early thymocyte or prothymocyte subpopulation, 5/25 were derived from a common thymocyte subpopulation, and 1/25 was derived from a mature (OKT3+) subpopulation These data suggest that is it now possible to define stages of T-cell differentiation that can be related to T-cell malignancies in humans

Pirenzepine distinguishes between different subclasses of muscarinic receptors

Abstract: Some antagonists exhibit tissue selectivity in their pharmacological antagonism of muscarinic responses. However, the affinity constants for equilibrium binding of classical antagonists to muscarinic receptors in subcellular preparations have shown only small variations in different peripheral tissues and regions of the brain. The binding curves do not deviate significantly from the simple Langmuir isotherm, indicating apparent homogeneity of the receptor population in any given region. In contrast, heterogeneity has been detected by agonist binding studies but this may arise from different environmental or coupling restraints on the agonist-induced conformational change and cannot be taken as evidence for different receptor subtypes. We report here binding studies using a new anti-muscarinic drug, pirenzepine, in which we found heterogeneity of binding that correlates well with the pharmacological activity.

Communication Networks: Toward a New Paradigm for Research

Abstract: The purpose of this book is to present what is currently known about communication networks and to illustrate methods of network analysis The 1st chapter describes a communication network in a small village of Korea Oryu Li in which basic principles are applied to collectively make decisions about family planning The following chapter discusses the convergence model of communication and network analysis in regard to its theoretical roots its concept meaning and implications in mass media communication Chapter 3 analyzes the communication network analysis Specifically it discusses how to measure communication network links and describes the levels of analysis Chapter 4 explains what are the methods of network analysis in regard to matrix manipulation NEGOPY direct factor analysis smallest space analysis and SOCK and COMPLT The following chapter discusses network variables in an attempt to explain individual behavior Specificially it analyzes personal network effects on individual behavior the effects of cliques systems effects and threshold effects Chapter 6 attempts to explain communication networks in group and system performances Many examples of the Korean family planning experience are used to support this analysis The methodology of assessing the determinants of who is linked to whom social determinants of network link the stability of network links over time and the multiplexity of network links are the main subjects discussed chapter 7 Chapter 8 is a summary of what type of research is currently being done in communication networks Specifically it discusses the methodology advantages of network analysis problems associated with this type of analysis and how to put this network analysis into use Tables and charts as well as a glossary are provided

Measuring health status in arthritis ; the arthritis impact measurement scales.

Abstract: A multidimensional index that measures the health status of individuals with arthritis has been developed. The Arthritis Impact Measurement Scales (AIMS) are a combination of previously studied and newly created health status scales which assess physical, emotional, and social well-being. The self-administered AIMS questionnaire has been pilot tested in a mixed arthritis population. Results indicate that the instrument is practical and that it generates scalable, reliable, and valid measures of both aggregated and disaggregated health status. The AIMS approach to health status measurement should prove useful for evaluating the outcomes of arthritis treatments and programs.

Evolutionary biology of parasites

Abstract: In spite of the fact that parasites represent more than half of all living species of plants and animals, their role in the evolution of life on earth has been substantially underestimated. Here, for the first time within an evolutionary and ecological framework, Peter Price integrates the biological attributes that characterize parasites ranging from such diverse groups as viruses, bacteria, protozoa, and fungi, to helminths, mites, insects, and parasitic flowering plants. Synthesizing systematics, ecology, behavioral biology, genetics, and biogeography, the author outlines the success of parasitism as a mode of life, the common features of the wide range of organisms that adopt such a way of life, the reasons for parasites' extraordinary potential for continued adaptive radiation, and their role in molding community structure by means of their impact on the evolution of host species. In demonstrating the importance of parasitic interactions for determining population patterns and geographical distributions, Dr. Price generates further discussion and suggests new areas for research.

Cultural expectations of thinness in women.

Abstract: The cultural pressures on women to be thin and diet have been linked to the expression of serious eating disorders such as anorexia nervosa. The current study attempts to document and quantify the shift toward a thinner ideal shape for females in our culture over the last 20 years. Data from Playboy centerfolds and Miss America Pageant contestants indicated a significant trend toward a thinner standard. Over the same period there was a significant increase in diet articles in six popular women's magazines. These changes occurred within the context of increasing population weight norms for young women. Biosocial implications including the apparent recent increase in anorexia nervosa are discussed.

Population Marginal Means in the Linear Model: An Alternative to Least Squares Means

Abstract: The parameter concept in the term least squares mean is defined and given the more meaningful name population marginal mean; and its estimation is discussed.

Primary hyperparathyroidism. Incidence, morbidity, and potential economic impact in a community.

Abstract: We examined the incidence and clinical and economic consequences of primary hyperparathyroidism in residents of Rochester, Minn, from 1965 through 1976; 90 cases were found. From January 1, 1965, to June 31, 1974, the average annual incidence was 7.8 +/- 1.2 (mean +/- S.D.) cases per 100,000 population. However, after the introduction of routine measurement of serum calcium, the average annual incidence rose to 51.1 +/- 9.6 cases per 100,000. Even after availability of routine measurement of serum calcium, the annual incidence of primary hyperparathyroidism among persons 39 years of age or younger remained below 10 cases per 100,000. However, the annual incidence increased sharply in persons 40 or more years of age, reaching 188 cases per 100,000 among women 60 years of age and over and 92 cases per 100,000 among men 60 and over. For the last 1.5 years of the study, the average annual age-adjusted incidence of primary hyperparathyroidism was 27.7 +/- 5.8 per 100,000. The frequency of urolithiasis fell from 51 to 4 per cent (P less than 0.001), and the proportion of cases without symptoms or complications of primary hyperparathyroidism rose from 18 to 51 per cent (P less than 0.005). The median charge in 1977 for diagnosis and treatment of primary hyperparathyroidism was $1700. (N Engl J Med 302:189-193, 1980).

Bacterioplankton secondary production estimates for coastal waters of british columbia, antarctica, and california.

Abstract: The principal objective of this study was to quantify the rate of heterotrophic bacterioplankton production. Production was estimated by two approaches: (i) measurement of increasing bacterial abundance with time in filtered (3-μm pore size) seawater and (ii) estimation of bacterial deoxyribonucleic acid synthesis by tritiated thymidine incorporation in unfractionated seawater. The two approaches yielded comparable results when used at the Controlled Ecosystem Population Experiment (Saanich Inlet, British Columbia, Canada), at McMurdo Sound (Antarctica), and off Scripps Pier (La Jolla, Calif.). Estimated bacterioplankton production was lower in Antarctic samples (ranging from ∼0 to 2.9 μg of C liter−1 day−1) than in those from the other two sites (ranging from 0.7 to 71 μg of C liter−1 day−1). In all three regions studied, it appeared that a significant fraction of the total primary production was utilized by the bacterioplankton and that substantial growth could occur in the absence of large particles. These results support the conclusion that bacterioplankton are a quantitatively important component of coastal marine food webs.

Development of the hippocampal region in the rat. I. Neurogenesis examined with 3H-thymidine autoradiography.

Abstract: Neurogenesis in the rat hippocampal region was examined with 3H-thymidine autoradiography. The rats in the prenatal groups were the offspring of pregnant females given two injections of 3H-thymidine on consecutive days in an overlapping series: embryonic (E) day E13+E14, E14+E15,…, E21+E22. The rats in the postnatal (P) groups were injected in two nonoverlapping series: first, the day of birth (PO) and P1, P2+P3,…, P18+P19; second, P0–P3, P4–P7,…, P16–P19. On 60 days of age, the percentage of labelled cells and the proportion of cells added during each day of formation were determined at several anatomical levels within each structure of the hippocampal region (entorhinal cortex, parasubiculum, presubiculum, subiculum, Ammon's horn, and the dentate gyrus) and the hippocampal rudiment (tenia tecta, indusium griseum). The neurons in each structure arise in overlapping, but still significantly different, waves: the hippocampal rudiment between E16–E17; the entorhinal cortex between E15–E17; the para- and presubiculum between E16–E19; the subiculum between E16–E18; large cells in strata oriens, radiatum, lacunosum-moleculare of Ammon's horn between E15–E17; Ammon's horn pyramidal cells between E17–E19; large cells in the dentate hilus and molecular layer between E15–E19. Dentate granule cells begin to originate on E17, and 10% of the population forms after P18. There are three characteristic gradients of formation within structures. First, deep cells are generated before superficial cells. Second, cells closer to the rhinal fissure are formed before those lying farther away (“rhinal to dentate” gradient). Third, later forming cells are flanked by earlier forming superficial and deep cells (“sandwich gradient”) in the entorhinal cortex (layer III cells originate after layers II and IV), Ammon's horn (pyramidal cells originate after large cells in strata oriens, radiatum, and lacunosum-moleculare), and the dentate gyrus (granule cells originate after large cells in the hilus and molecular layer). There is a “rhinal to dentate” gradient between structures. The entorhinal cortex starts first, next is the subiculum, then field CA3 of Ammon's horn, and finally, the dentate gyrus. Two structures are exceptions to this gradient. The para- and presubiculum form significantly later than the subiculum, and CA1 forms significantly later than adjacent CA3 cells; this late neurogenesis may be related to prominent thalamic input to both structures. Neurogenetic gradients between the cells providing laminated afferent input to the Ammonic pyramidal and dentate granule cells correlate with their order of termination: afferents from progressively later-originating cells terminate progressively closer to the cell body. Topographic hippocampal projections along the dorsoventral axis correlate with formation patterns in target structures: dorsal hippocampal fibers project to zones occupied by earlier-forming cells in the lateral septal nucleus and pars posterior of the mammillary body; ventral hippocampal fibers project to zones occupied by later-forming cells in these structures.

When Is It Coevolution

Abstract: 'Coevolution' may be usefully defined as an evolutionary change in a trait of the individuals in one population in response to a trait of the individuals of a second population, followed by an evolutionary response by the second population to the change in the first. 'Diffuse coevolution' occurs when either or both populations in the above definition are represented by an array of populations that generate a selective pressure as a group. Ehrlich and Raven's (1964) classic paper on the interactions of butterflies and plants was the first essay explicitly focused on coevolution. However, they did not define coevolution, and butterflies were neither stated nor implied to have been the single populations or array of herbivores that have generated the plant traits that they discuss as causing butterfly distributions on host plants. I believe that the lack of an original definition of 'coevolution,' the inapplicability of the example chosen by the original advocates of the use of the term, and the obvious commonplace nature of coevolutionary events in the history of plant-animal interactions have led to misleading uses of the term in contemporary evolutionary thought and studies. Here, I wish to call for more careful attention to the use of 'coevolution' as a word and concept. There are three conspicuous misuses at present: 1) It is commonly assumed that a pair of species whose traits are mutualistically congruent have coevolved. For example, it is quite possible that the fruit traits of a mammal-dispersed seed coevolved with the mammal's dietary needs. However, it is also quite possible that the mammal entered the plant's habitat with its dietary preferences already established and simply began feeding on the fruits of the species that fulfilled them. When this occurs, it is those species that are most exactly congruent which will appear most coevolved yet are likely to be the least coevolved. Are the hard seeds of those aridland trees dispersed by passage through a contemporary mammal gut coevolved with the mammal? Not necessarily. 2) In similar manner, a herbivore parasitic on a plant is often thought of as coevolved with the defense timing, chemistry, morphology, etc. However, when a parasite arrives in a new habitat, it will feed on those species whose defense traits it can circumvent because of the abilities it carries at the time. Such a parasite cannot be distinguished from one that evolved the ability to circumvent a defense while in trophic contact with its host. 3) When other evidence makes it clear that a parasite has evolved traits to circumvent the defenses of its host, it is frequently automatically assumed that coevolution has occurred. However, it is not necessary to conclude that the defense trait circumvented was evolutionarily produced in response to the parasite in question. In fact, it is likely that many defense traits of plants were produced through coevolution with animals no longer present in their habitat or no longer parasitizing them if present. Strongly coevolved parasite-host systems probably as often proceed to ecological independence of the participants as to relatively benign parasitism. In summary, I plead for the retention of the usefulness of 'coevolution' by removing it from synonymy of usage with 'interaction, '"symbiosis, '"mutualism,' and 'animal-plant interaction.' A bee is not necessarily coevolved with the flower it pollinates, a caterpillar is not necessarily

The palliation of brain metastases: Final results of the first two studies by the radiation therapy oncology group

Abstract: Five schedules of whole brain irradiation ranging from 4000 rad/4 weeks to 2000 rad/ 1 week have been evaluated in two sequential phase III randomized Radiation Therapy Oncology Group (RTOG I studies to determine palliative effectiveness in patients with metastatic brain disease. Improvement in neurologic function status and maintenance of improved or stable neurologic function were utilized as measures of response. All treatment schedules were comparable with respect to frequency of improvement, duration of improvement, time to progression, survival and palliative index. Important prognosticators of response included initial neurologic function and general performance status. Administration of steroids during irradiation favored more rapid improvement; for neurologic-function-3 patients, it increased the overall frequency of improvement. This result must be interpreted with caution since the administration of steroids was not controlled in either study. Patients whose disease is controlled at the primary site and in whom brain is the only site of metastases, constitute a prognostically favorable group; they may benefit from whole brain irradiation to higher doses. This population is currently under investigation in a third RTOG study.

Nonspecific Psychological Distress and Other Dimensions of Psychopathology: Measures for Use in the General Population

Abstract: • This interview study investigated nonspecific psychological distress in the general population. A probability sample of 200 adults was drawn from heterogenous sex, class, and ethnic groups in New York City. Twenty-five scales were developed. Eight reflect a single dimension of nonspecific distress (eg, Poor Self-esteem, Sadness, and Perceived Physical Health) and 17 are distinct from these and from each other (eg, False Beliefs and Perceptions, Manic Characteristics, Insomnia, Antisocial History, and illness-linked Somatic Problems). Both sets of scales have become part of a new interview instrument, the Psychiatric Epidemiology Research Interview (PERI). Questions are raised about the nature of nonspecific distress in relation to Frank's construct of "demoralization," the value of the measured dimensions of psychopathology that contrast with it, and the relation of PERI, which uses a self-report format, to diagnostic interviews developed here and abroad.

The effects of education on health

Abstract: This paper investigates the effects of education on health. The determinants of mortality are receiving increasing scrutiny because the rate of mortality reduction in the developing world appears to have slowed at levels of life expectancy below those thought attainable only a few years ago. The first perspective employed in this paper is a broad assessment of the socioeconomic determinants of mortality on a cross-national basis; using aggregate data, this paper contains a review and a reanalysis of the large body of literature that has accumulated on international differences in mortality and life expectancy. The second perspective sharpens the focus by concentrating on the relationship between education and mortality since the cross-national evidence suggests that education, or its proxy literacy, is the most important variable involved. A theoretical model of the relationship between parental education and child health is developed and used to describe how aggregate and individual data may give different estimates of the relationship. The third perspective employed reviews and reanalyzes the evidence at the subnational level. Individual evidence is reviewed on the relationship between parental education and both child nutrition and child mortality.

A monoclonal antibody reactive with human peripheral blood monocytes.

Abstract: A monoclonal antibody directed at a determinant on human peripheral blood monocytes was produced and characterized. This hybridoma antibody, termed OKM1, was reactive by indirect immunofluorescence and complement- (C) mediated lysis with adherent mononuclear cells. OKM1 was unreactive with lymphocytes, thymocytes, lymphoblastoid cell lines, and tumor cells of the T or B cell lineage. In contrast, acute myelomonocytic leukemia cells and granulocytes were reactive with the antibody. Pretreatment of peripheral blood mononuclear cells with OKM1 and C before culture with soluble antigens totally abolished their antigen-induced proliferative response. This function was restored by addition of 1% adherent cells. These findings provided additional support for the notion that OKM1 was reactive with monocytes. In addition, OKM1 appeared to define two distinct populations of monocytes; an adherent population of large cells bearing surface Ia determinants and a nonadherent population of small, Ia-negative cells. These OKM1+ Ia- cells were found to be a contaminant of most fractionated mononuclear cell subsets including the E-SIg-Null cell population.

Socio-cultural factors in the development of anorexia nervosa

Abstract: A population of professional dance (N = 183) and modelling (N = 56) students, who by career choice must focus increased attention and control over their body shapes, was studied. Height and weight data were obtained on all subjects. In addition, a questionnaire that is useful in assessing the symptoms of anorexia nervosa, the Eating Attitudes Test (EAT), was administered. Results of these tests were compared with those of normal female university students (N = 59), patients with anorexia nervosa (N = 68), and music students (N = 35). Anorexia nervosa and excessive dieting concerns were overrepresented in the dance and modelling students. Twelve cases (6.5%) of primary anorexia nervosa were detected in the dance group. All but one case developed the disorder while studying dance. Within the dance group those from the most competitive environments had the greatest frequency of anorexia nervosa. These data suggest that both pressures to be slim and achievement expectations are risk factors in the development of anorexia nervosa. The influence of socio-cultural determinants are discussed within the context of anorexia nervosa as a multidetermined disorder.

Growth of factor-dependent hemopoietic precursor cell lines.

Abstract: Cell lines have been produced from long-term cultures of mouse bone marrow that require a factor, present in WEHI-3 conditioned medium (CM) or in spleen CM, for their sustained growth. The cell lines were obtained from nonvirus-treated cultures, are nonleukemic, maintain a normal karyotype, and form colonies showing granulocyte maturation when plated in soft agar. Granulocyte/macrophage (GM) colony-stimulating factor is not the inductive moiety involved in the maintenance of proliferation of these cells. It is suggested that the cell lines represent a self-renewing population of cells ancestral to GM colony-forming cells, which may be responding to a hitherto unrecognized regulator.

Relationship of plasma insulin levels to the incidence of myocardial infarction and coronary heart disease mortality in a middle-aged population.

Abstract: The possible role of plasma insulin levels as a risk factor of coronary heart disease has been studied in a population of 7246 non diabetic, working men, aged 43–54 years, initially free from heart disease, and followed for 63 months on average. 128 new coronary heart disease events (non fatal myocardial infarction and coronary related deaths) were detected during this period. The annual risk is analysed by a multivariate model including age, serum cholesterol and triglycerides, blood pressure, smoking, obesity, plasma glucose and insulin fasting and 2 hours after a 75 g oral glucose load. It is shown that the fasting plasma insulin level and the fasting insulin-glucose ratio are positively associated with risk independent of the other factors. The same variables, 2 hours after the glucose load are also positively associated with risk but their contributions are not significant in the multivariate analysis. It is concluded that high insulin levels may constitute an independent risk factor for coronary heart disease complications in middle aged non diabetic men.

Testing the quantity-quality fertility model: the use of twins as a natural experiment.

Abstract: The predictive content of the quantity-quality model of fertility and the empirical information required for verification under a minimal set of restrictions on the utility function is described. It is demonstrated that commodity-independent compensated price effects must be known to infer the existence of the unobservable interdependent shadow prices of the model with a relatively weak structure improsed on preference orderings. A method of using multiple birth events to substitute for these exogenous prices is proposed and applied to household data from India. (Authors)

Positive selection for loss of tetracycline resistance.

Abstract: A simple technique has been devised that allows direct plate selection of tetracycline-sensitive clones from a predominantly tetracycline-resistant population The technique is especially useful in genetic methodologies based on the use of tetracycline resistance transposons, such as Tn10 Potential uses of the method include selection of deletion mutants, fine-structure mapping, generalized mapping, construction of multiply marked strains, elimination of tetracycline resistance transposons and plasmids and cloning The technique is based on our finding that tetracycline-resistant cells are hypersensitive to lipophilic chelating agents, such as fusaric acid This finding supports the contention that certain metal ions critically facilitate tetracycline uptake and leads us to suggest possible molecular mechanisms for tetracycline resistance

The great fish war: an example using a dynamic Cournot-Nash solution

Abstract: In recent years there have been numerous international conflicts about fishing rights These conflicts are wider in scope than those captured by the model presented in this paper Yet the model sheds light on the economic implications of these conflicts as well as on the implications of other duopolistic situations in which the decisions of the participants affect the evolution of an underlying population of interest Our model has two basic features: the underlying population changes as a result of the actions of both participants, and each participant takes account of the other’s actions This strategic aspect is studied, for an example, by using the concept of a Cournot-Nash equilibrium in which each participant’s reaction depends on the stock of fish and not on previous behavior Thus, the model is a discrete-time analog of a differential game The paper examines the dynamic and steady-state properties of the fish population that results from the participants’ interactions

Dispersal Polymorphisms in Insects

Abstract: In many insects dispersal by flight occurs prior to reproduction, and the ability to fly is often lost once reproduction begins (37, 92). Thus, dispersal is viewed as an "evolved adaptation" characteristic of a particular stage in the ontogeny of the insect (91-93, 98) rather than a spontaneous response to current adversity. In certain groups of insects, species exhibit polymorphisms that affect flight ability. Variations in wing length and flight muscle development are the most obvious examples. In some species flight may be primarily an adaptation for dispersal, and the proportion of morphs capable of flight may be a reliable measure of level of dispersal. Adaptations for dispersal in animals are for the most part difficult to identify because locomotory move­ ments potentially serve many important functions (or produce many impor­ tant effects). Flight polymorphisms in insects are thus of particular interest in understanding the adaptive significance of dispersal in natural popula­ tions. This review focuses on two aspects of insect flight polymorphisms: how morphs are determined and how polymorphisms are maintained. I do not attempt to document all (or even most) examples of flight polymorphisms but instead consider possible answers to the following questions: Do differ­ ent morphs represent different genotypes, or do they represent alternative developmental patterns produced by a single genotype in response to differ­ ent sets of environmental inputs? What do studies of flight polymorphisms reveal about the evolutionary significance of dispersal? What are the selec­ tive advantages and disadvantages of the normal (winged, not necessarily most common) and flightless morphs in an insect population?

Homicide trends in the united states

Abstract: Unlike most other causes of death, homicide has been increasing in the United States, especially since the mid-1960s. Its impact is greatest among nonwhite men. The elimination of homicide would add approximately one and one-half years to their life span. This analysis examines trends and differentials using vital statistics data about homicide victims. A decomposition of components of change reveals that almost all of the rise in homicide mortality among nonwhites and a substantial fraction of the rise among whites results from the increasing use of firearms to kill people.

Intrathecal morphine inhibits substance P release from mammalian spinal cord in vivo

Abstract: The central terminals of small diameter primary sensory neurones associated with the transmission of noxious cutaneous stimuli are located predominantly in the superficial dorsal horn of the spinal cord1–3. Some of these neurones synthesize substance P (ref. 4) and transport this peptide to their central and peripheral terminals5–7. Substance P is released from the dorsal horn in vitro following potassium depolarization8,9; from spinal cord after electrical stimulation of dorsal roots10 and from dissociated sensory neurones grown in culture11. The iontophoretic application of substance P produces a long-lasting excitation of dorsal horn neurones that are also excited by noxious cutaneous stimuli12–14. One population of opiate receptors in the dorsal horn seems to be located on primary afferent terminals15–16; the release of substance P from primary sensory neurones is inhibited by opiates in vitro8,11. At present, however, there is no direct evidence that substance P is released from sensory neurones, in vivo, following activation of nociceptive afferents. We report here that substance P-like immunoreactivity is released from the mammalian spinal cord, in vivo, following chemical stimulation of sensory neurones with capsaicin and by the activation of high threshold peripheral afferents. Furthermore, release of substance P evoked by high intensity stimuli is completely inhibited by intrathecal morphine.