Different Categories Of Individuals Research Articles

Female mate choice by chemical signals in a semi-terrestrial crab

Information about the roles of both sexes in pair formation is required to better understand the mechanisms involved in sexual selection. Mate choice could depend on the courtship behavior, involving chemical, tactile and visual signals. We determined if Neohelice granulata mate choice is based on female or male choice, considering visual and chemical with contact and without contact signals between partners and different categories of individuals: receptive and unreceptive females; and large, small, mated or unmated males. Experiments showed that mate selection was based on receptive female's choice using chemical signals, but not visual ones. Since copulation occurs during high and low tides, water-borne chemical signals would be preferentially used during high tide, while contact ones during low tide. Females preferred large and unmated males, while males did not seem to recognize receptive females using chemical neither visual signals. Females were capable of detecting the presence of the chemical signals released by large and unmated males, but not its amount. It is proposed that small and mated males are probably releasing different types of chemical signals, not attractive to females, or that they are not emitting any signal.

The Dynamics and Dilemmas of the Niger Delta: A Discourse on Insecurity and Demographic Transition

Until recently, the Niger Delta was distinctive for empowering and transforming lives. The relative advantage of its cities blurred the inherent multidimensional consequences of oil exploration on the environment. Over time, the effects of oil spills on the inhabitants were massive. The people’s agony was exacerbated by perceived governmental neglect which accounted for the amplification of frustration and aggression among a large majority of the poor that constitute more than three-quarters of the population. As a result, different categories of individuals became activists committed to peaceful protests. However, with a plethora of insensitive and irresponsible governments, the legitimate means soon evolved into militancy, political thuggery and assassinations. Consequently, Niger Delta communities became synonymous with insecurity, pseudo-governance and youth restiveness. This article examined the trends and dimensions of the unholy dynamics that drove demographic transition in the region by highlighting the connections between the dilemma of a failed state and underdevelopment.

Molecular and functional characterization of macrophage migration inhibitory factor (MIF) homolog of human from lymphatic filarial parasite Wuchereria bancrofti

The ability of nematode parasites to survive in a highly complex immune system involves diverse strategies including production of a variety of host immune modulators. Various parasite-associated surface antigens or excretory and secretory products may possibly play a role in the host-parasite interactions and successful survival of parasite in their respective host. One among these molecules is a human cytokine homolog, macrophage migration inhibitory factor-1 (MIF-1) in various parasites. We identified a homolog of this cytokine from human lymphatic filarial parasite, Wuchereria bancrofti, expression cloned and investigated its molecular characteristics and catalytic properties. We also assessed the humoral reactivity of the recombinant MIF-1 of W. bancrofti (rWb-MIF-1) against sera belonging to different categories of individuals viz. microfilaremic, chronic patients, endemic normal, and non-endemic normal. Our results showed that the complete coding sequence of W. bancrofti is 1,078 bp, comprising two introns and three exons: first and second introns being 577 and 153 bp long, while the three exons I, II, and III being 108, 173, and 67 bp long, respectively. The rWb-MIF-1 was overexpressed in a salt-inducible host, Escherichia coli GJ 1158, and its functional activity was determined by dopachrome tautomerase and insulin reduction assays. The results of both the assays showed that the purified protein is functionally active and hence folded appropriately. The rWb-MIF-1 protein did not show elevation of specific IgG4 antibodies in microfilaremic cases, a hallmark in case of lymphatic filariasis, while it showed IgE reactivity in some of these cases (five out of ten).

Determinants and costs of natal dispersal in a lekking species

Avoidance of competition and inbreeding have been invoked as the major ultimate causes of natal dispersal, but proximate factors such as sex, body condition or birth date can also be important. Natal dispersal is expected to be of particular importance to understanding the ecological and evolutionary implications of dispersal strategies, since 1) numerous evidences suggest that individual differences in dispersal strategies are expressed early in life (i.e. at the onset of dispersal movement), 2) ultimate and proximate factors are more likely to act during this stage and 3) this stage is associated with the highest mortality rates in most vertebrates. We analysed the natal dispersal (hereafter, dispersal) behaviour in 100 marked individuals of a lekking species, the North African houbara bustardsChlamydotis undulata undulata, during four years. We investigated the effects of proximate factors on dispersal pattern and distance, as well as the mortality cost associated with movement using multievent models, allowing uncertainty in sex assignment and mixture of live recaptures and dead recoveries. Overall, males exhibited longer dispersal distances than females, contrary to the common pattern in birds. Moreover, males in poorer body condition moved further than those in better condition, whereas distance was independent of body condition in females. Finally, survival rates during dispersal were lower for females than for males and were negatively correlated with the distances covered with a similar distance‐survival slope in the two sexes. Collectively, our results suggest that 1) there is substantial dispersal cost in both sexes, 2) dispersal is strongly male‐biased, 3) this bias is unlikely to be explained by differential movement costs of each sex, and 4) dispersal differences found across different categories of individuals are in broad agreement with both the inbreeding avoidance and intraspecific competition mechanisms for dispersal.

Sex Differences in Sand Lizard Telomere Inheritance: Paternal Epigenetic Effects Increases Telomere Heritability and Offspring Survival

BackgroundTo date, the only estimate of the heritability of telomere length in wild populations comes from humans. Thus, there is a need for analysis of natural populations with respect to how telomeres evolve.Methodology/Principal FindingsHere, we show that telomere length is heritable in free-ranging sand lizards, Lacerta agilis. More importantly, heritability estimates analysed within, and contrasted between, the sexes are markedly different; son-sire heritability is much higher relative to daughter-dam heritability. We assess the effect of paternal age on Telomere Length (TL) and show that in this species, paternal age at conception is the best predictor of TL in sons. Neither paternal age per se at blood sampling for telomere screening, nor corresponding age in sons impact TL in sons. Processes maintaining telomere length are also associated with negative fitness effects, most notably by increasing the risk of cancer and show variation across different categories of individuals (e.g. males vs. females). We therefore tested whether TL influences offspring survival in their first year of life. Indeed such effects were present and independent of sex-biased offspring mortality and offspring malformations.Conclusions/SignificanceTL show differences in sex-specific heritability with implications for differences between the sexes with respect to ongoing telomere selection. Paternal age influences the length of telomeres in sons and longer telomeres enhance offspring survival.

The construction of next-generation matrices for compartmental epidemic models

The basic reproduction number (0) is arguably the most important quantity in infectious disease epidemiology. The next-generation matrix (NGM) is the natural basis for the definition and calculation of (0) where finitely many different categories of individuals are recognized. We clear up confusion that has been around in the literature concerning the construction of this matrix, specifically for the most frequently used so-called compartmental models. We present a detailed easy recipe for the construction of the NGM from basic ingredients derived directly from the specifications of the model. We show that two related matrices exist which we define to be the NGM with large domain and the NGM with small domain. The three matrices together reflect the range of possibilities encountered in the literature for the characterization of (0). We show how they are connected and how their construction follows from the basic model ingredients, and establish that they have the same non-zero eigenvalues, the largest of which is the basic reproduction number (0). Although we present formal recipes based on linear algebra, we encourage the construction of the NGM by way of direct epidemiological reasoning, using the clear interpretation of the elements of the NGM and of the model ingredients. We present a selection of examples as a practical guide to our methods. In the appendix we present an elementary but complete proof that (0) defined as the dominant eigenvalue of the NGM for compartmental systems and the Malthusian parameter r, the real-time exponential growth rate in the early phase of an outbreak, are connected by the properties that (0) > 1 if and only if r > 0, and (0) = 1 if and only if r = 0.

Preferences for redistribution in the land of opportunities

This paper explores how individual preferences for redistribution depend on future income prospects. In addition to estimating the impact of individuals' socioeconomic background and of their subjective perceptions of future mobility, we employ panel data to construct ‘objective’ measures of expected gains and losses from redistribution for different categories of individuals. We find that such measures have considerable explanatory power and perform better than ‘general mobility’ indexes. We also find that preferences for redistribution respond to individual beliefs on what determines one's position in the social ladder. Ceteris paribus, people who believe that the American society offers 'equal opportunities are more averse to redistribution.

Genetic Evidence for the Demic Diffusion of Agriculture to India

Genetic Evidence for the Demic Diffusion of Agriculture to India

Medicare Play-by-Play: A Review of Theodore Marmor's The Politics of Medicare

For at least seven decades the issue of financing health care has been debated in this country. While the intensity of the battle has varied greatly, the underlying drive for reform has been well identified and remarkably consistent. Theodore Marmor's The Politics of Medicare is an exceptional book which documents this period.In its most general description the era has experienced persistent and growing support for financing reform that would have, at least, characteristics of universality, comprehensive coverage and delivery by a system capable of serving many diverse constituencies. Nothing in these attributes is novel, and each can be identified as present, to varying degrees, in health care financing systems operating throughout the industrial world. Broad goals always attract advocates of every stripe, but the scene changes rapidly when the process of definition commences. Even the most obvious component, universality, precipitates a conflict when the details of exactly who will be included in the covered population start to be hammered out. Endless examples of intense controversy exist over access to federal, state and local programs by the many different categories of individuals who live within this country.

Tax Rates and Work Incentives in the Social Security Disability Insurance Program: Current Law and Alternative Reforms

The Social Security Disability Insurance (SSDI) Program has long been criticized by economists for its apparent work disincentives stemming from the imposition of 100-percent tax rates on earnings. However, the program has been modified in recent years to allow recipients to keep some of their earnings for fixed periods of time. Moreover, additional proposals have been made for lowering the tax rate further and for providing various additional financial work incentives. We use the basic labor supply model to show the expected effect of these reforms on work effort. In addition, we provide a numerical simulation that shows the magnitude of the monetary incentives provided by the reforms for different categories of individuals. We find that the proposed reforms have ambiguous effects on work effort and could, contrary to perceived wisdom, possibly reduce work effort and increase the number of SSDI recipients. However, the simulations show that reforms based on earnings subsidies for private employers are more likely to increase work effort and to lower the caseload.

Neurobiological correlates of visual and olfactory recognition in sheep

This paper describes neurophysiological and behavioural experiments which investigate the ability of sheep to recognise different individuals using visual and olfactory cues. Behavioural experiments using Y-mazes with back-projected images of faces have shown that sheep can distinguish between the faces of sheep and humans when the faces are presented in a frontal view although they have more difficulty in doing so if the faces are presented in profile, upside down or with the eyes obscured. Single-cell electrophysiological recordings made from neurones in the temporal cortex have shown that sheep, like non-human primates, have cells in this region that code preferentially for facial stimuli and that their responses are also diminished or abolished if the faces are presented upside-down, in profile, or with the eyes obscured. Different sub-populations of cells code for faces of similar social and emotional significance. Thus one population of cells codes for faces with horns and their responses are also modulated by the size of the horns, another population codes for faces of animals of the same breed, and particularly familiar animals, and a final population codes for faces of humans and dogs. Visual cues from body shape and posture are also important for recognition of different classes of individual. Field studies have shown that sheep find it difficult to recognise humans approaching them if they change their posture to quadrupedal as opposed to a bipedal one. Electrophysiological studies have also demonstrated the presence of cells in the temporal cortex which respond preferentially to the sight of a human body shape and their activity is influenced by body orientation, posture and direction of movement. In some cases alterations to the human's appearance can also influence their activity. Olfactory recognition studies have used electrophysiological, in vivo sampling and behavioural analyses to establish the mechanisms whereby a maternal ewe develops the ability to selectively recognise the odour signatures of its own lambs within the first few hours of giving birth. Electrophysiological recordings from mitral cells in the olfactory bulb have shown that none of them respond preferentially to lamb odours pre-partum, when the ewes show no interest in lambs, whereas 60% of them do so after ewes have bonded with their lambs. A sub-population of mitral cells also responds differentially to own and alien lamb odours post-partum. Neurochemical studies have shown that lamb odours do not evoke transmitter release within the olfactory bulb pre-partum whereas, post-partum, own lamb odours stimulate release of the intrinsic amino acid transmitters, GABA and glutamate whereas both own and alien lamb odours evoke equivalent increases in the release of the centrifugal pathway transmitters, acetylcholine and nonadrenaline. Overall these experiments provide compelling evidence that the sheep, which is after all a social animal, makes use of sophisticated visual cues from the face and body and of olfactory cues from the body and wool to recognise different individuals. The neural pathways which are involved in both of these recognition processes also show remarkable evidence of plasticity. However, there appears to be a much closer link between recognition and emotional significance demonstrated in the coding strategies employed by the neural circuits involved in individual recognition in the sheep brain compared to that of a primate and, indeed, they seem to be organised more for identifying a small number of different categories of individuals rather than for a large number of individuals per se. It is possible therefore that social evolutionary pressures to specifically identify large numbers of individuals of similar emotional significance has been achieved by weakening the organisational influence of affect on coding strategies of cells in the temporal cortex in favour of a more extensive feature detection system allowing accurate discrimination between a large number of individuals and their expressions under a number of different viewing conditions.

Premarital sexual standards for different categories of individuals

A survey study of 666 undergraduate students was conducted to examine how standards for a target depend on the target's personal relevance, gender, and age. Whether male and female students have different sexual attitudes was also examined. Respondents were randomly assigned to complete a sexual permissive scale for one type of target. No evidence was found for a double standard, but age and personal relevance of the target affected the standards endorsed. Less permissiveness was endorsed for younger targets and targets who were “personal” (e.g., “sister” or “brother”) to the respondent. Furthermore, female respondents were less permissive than male respondents. Whether this gender difference reflects women's greater sexual conservatism or women's lack of power in the social structure is also discussed.

Breeding Dispersal in the Collared Flycatcher (Ficedula albicollis): Possible Causes and Reproductive Consequences

SUMMARY (1) Correlates of breeding dispersal (between years) in the collared flycatcher were analysed using data from a population on the Swedish island of Gotland in the Baltic. (2) Females on average moved further than males. Only 8% of the males and 2% of the females reoccupied their previous nest box. Individual size or body condition were not related to breeding dispersal. (3) Among females both total failures and reduced number of fledged young were associated with long subsequent movements in yearlings, whereas dispersal of older individuals was not related to previous breeding success. The pattern of breeding dispersal was similar in males but the difference was not significant. (4) Males that remained unpaired throughout the breeding season moved further in the next year than did mated males. There were no differences in breeding dispersal patterns between polygynous and monogamous males, nor between monogamous and secondary females. (5) Occupation of previous nest boxes by breeding tits were significantly correlated with dispersal distances in 2-year-old males, but not in older males. Female breeding dispersal was not related to this factor. (6) Males breeding for the first time in their natal area subsequently moved shorter distances than males breeding in another area. Females showed no significant differences in dispersal with respect to their birth place. (7) Breeding dispersal distance was not correlated with age when breeding success, occupation of previous nest boxes by breeding tits and distance from natal area were controlled for. (8) The reproductive correlates of movements were different for different categories of individuals. There was a negative correlation between distance moved and subsequent fitness (measured as survival and number of recruits produced) among previously successful females, whereas the trend was the opposite among previously unsuccessful females. These relationships were most prominent among young females. There were no significant correlations of dispersal and subsequent reproductive performance in males. (9) The hypothesis is advanced that breeding dispersal distances (to some extent) reflect individual choices among available territories, in that individuals with little and/or bad local experience disperse more because they benefit from exploring more sites before

Acceptance of management science recommendations: The role of cognitive styles and dogmatism

The results of studies concerning the effect of personality variables on the successful implementation of management science recommendations have been equivocal. Although several studies in the past have shown significant effect of personality variables, recently a few studies have shown that lack of any impact due to these variables. Very few studies have considered the effect of dogmatism which has been shown in psychological literature as a powerful restrictor in entertaining new ideas and suggestions for decision making. Our study examines the effect of dogmatism and cognitive styles in choosing management science recommendations. The results show the need for special efforts required in choosing report format and style to suit different categories of individuals with varying cognitive skills and level of open-mindedness. Even subtle variations seem to produce the difference between success and failure of implementation.

Rozmieszczenie osobników i złowień w wyspowej populacji nornicy rudej

Bujalska G. & Mieszkowska D., 1984: Distribution of individuals and captures in an island population of the bank vole. Acta theriol., 29, 11: 147—158 [With 4 Tables & 3 Figs.] Estimates of numbers were made five times a year over the period from 1975—1980 in a population of Clethrionomys glareolus (Schreber, 1780) living on Crabapple Island in northeastern Poland, using the CMR method. Parallel to the above the standing crops of herb biomass v/ere estimated in four forest associations covering the island. A total of 1812 individuals and 22,959 captures were recorded. It was found that fluctuations in the number of individuals and their captures coincide in all the associations, whereas the latter differ in respect of the average number of individuals recorded there and the number of their captures. The largest number of individuals was found in the camp and highly productive herb layer Circaeo-Alnetum and the smallest in the Tilio-Carpinetum typicum association situated on the highest and dryest ground. The largest number of captures was obtained in Circaeo-Alnetum and Tilio-Carpinetum stachyetosum silvaticae associations. The pictures obtained for the different categories of individuals (males, females and among them mature and immature animals) differed, which points to their different habitat requirements. A proportionate increase in the number of captures does not always accompany increase in the number of individuals of a given category: in some associations in which, although a large number of individuals of the given category is observed, the number of captures is small, and vice versa. This indicates that the term habitat optimum can be taken to mean several things. A discussion is given of the importance of determining the habitat requirements of different elements of popopulation structure in order to define their role in the ecosystem. Attention was also given to the methodical aspect, connected with estimate of numbers by means of snap-traps or the use of the trap-nights index.

Suburbanization and Change in the American Family

Suburbanization and Change in the American Family Episodic accounts of social processes have proven generally unsatisfying to recent historians. One reason that Warner's Streetcar Suburbs so quickly attained the status of a classic in urban history is that it makes processual sense out of a range of phenomena formerly of interest mainly to a variety of antiquarians. Warner's inquiry into the growth of residential Boston in the late nineteenth century taught urban historians that suburbanization has been, for a century, a critical process of American urbanization, and not just a characteristic alarum of the 1950s. The most suggestive element of Warner's account has been its indication that even in the era of the streetcar, American cities did not simply expand: cities differentiated as they grew, redistributing individuals and activities in non-random ways, serving different categories of individuals differently. Warner's work conveyed the powerful message that the restructuring of social space within cities has affected lives in systematic ways which call for close scholarly attention.1 Although systematic social historians are in Warner's debt for his processual account, Streetcar Suburbs is nevertheless a case study, and, like much of Warner's work, proceeds intuitively rather than by spelling out implications. Among the most important of these implications is the notion that the family not only affected but was systematically affected by urban form. The present paper pursues this line of analysis.

Restrictions sur les échanges et les paiements internationaux

Discussions on convertibility cannot avoid considering at one and the same time restrictions on international trade and payments. In particular , the concrete results of decisions taken in one of these two fields can only be perceived in the light of their effects on the other. The role of international agreements on the abolition of trade and pay¬ ments restrictions is discussed in relation to the work of the O. E. E. C. It is concluded that a country should choose its trade and payments policy taking into account the possibilities-offered by international agreements rather than acting unilaterally. In any case , errors of judgment often result from the failure to consider the concrete results of policy decisions for the different categories of individuals or organizations directly affected by those decisions. The concept of the general interest of the country is insufficient. It may be noted, also, that the results of decisions taken by one country can depend largely upon decisions taken by other countries. The example of commodity shunting illustrates this. Although there is a need for wider international discussion of all aspects of trade and payments problems it is likely that results will be achieved more rapidly through existing international organizations once the dimensions of the problems posed are realized.