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1.
Aim To use molecular data to test for dispersal structuring in the immigration history of an amphidromous community on an island. Location The Caribbean island of Puerto Rico. Methods Mitochondrial DNA sequences were obtained from 11 amphidromous species, including shrimps, fish and a gastropod, sampled from throughout the island. The timing of population expansion (TE) in each species was calculated using nucleotide variation and molecular clock dating methods. The order of species accumulation was then reconstructed (oldest to most recent estimate for TE), and groups of species with non‐overlapping estimates for TE were identified. The temporal span and average immigration rate for each group were calculated and compared with expectations of two previously published models of island immigration [the ‘dispersal‐structured model of island recolonization’ ( Whittaker & Jones, Oikos, 1994 , 69 , 524–529), which predicts short phases of rapid immigration followed by extended phases with relatively slow immigration rates; and the ‘colonization window hypothesis’ ( Carine, Taxon, 2005 , 54 , 895–903), which suggests that opportunities for island colonization are temporally constrained to discrete waves of colonization]. Results The molecular data indicated the immigration history of Puerto Rican amphidromous fauna from the late Pleistocene through the Holocene and identified two groups of species with non‐overlapping estimates for TE and one group that overlapped with the other two groups. The temporal span, average immigration rate and lack of discreteness between all three groups indicated a continuum of immigration rather than distinct phases of species arrivals. Main conclusions This study did not support the expectations of the immigration models and suggested that amphidromous species from Puerto Rico comprise a single class of marine‐based dispersers. The immigration sequence we report probably reflects a recolonization chronology in this community, in keeping with the notion of species turnover through time. Four areas of future research into the immigration history of amphidromous species on islands are identified, and indicated the possibility that equilibrium processes govern long‐term community change in amphidromous biota on islands.  相似文献   

2.
This article aims to contribute to the study of migration and nation-building in stateless nations. It explores the media portrayal of Italian immigration in Wales after the 1997 devolution. It assesses why Italian immigrant narratives have figured prominently in the Welsh media after devolution. It shows that, being seen as Wales's ‘model minority’, Italians have ideally served a reinforcement of the surrounding inclusive rhetoric, one that draws on an old-standing Welsh tolerance-myth. Thus, this article argues that stateless nations aiming to gain increasing autonomy can use their immigration history to construct and disseminate a tolerant and inclusive national image, one that aims to foster both indigenous people and migrants' sense of national belonging.  相似文献   

3.
Studies with birds have shown that presence and density of resident conspecifics and heterospecifics can influence patterns of habitat selection. There have been few studies on the effects of social cues on rates of immigration in mammals. We report results from a long-term live trapping study of immigration in two species of voles, Microtus ochrogaster Wagner, 1842 and Microtus pennsylvanicus Ord, 1815, in bluegrass habitat in east-central Illinois, USA. We compare immigration into control sites from which no individuals of either species were removed with immigration into experimental sites from which either conspecifics or heterospecifics were removed. We focus on characteristics of immigrants and rates of immigration in relation to density in destination habitats. Within each species, immigrants into control and removal sites were similar with respect to body mass and reproductive condition, indicating no major differences in the physical condition of immigrants into sites with established populations and sites without established populations. For both species, density of conspecifics at a site positively influenced rate of immigration at that site. Density of heterospecifics at destination sites did not significantly influence rate of immigration for either species. These results suggest that site selection by dispersing M. ochrogaster and M. pennsylvanicus is characterized by conspecific attraction.  相似文献   

4.
In this article I examine the changing social and historical context of exchange and ritual amongst the Anganen of the Southern Highlands Province of Papua New Guinea, a neglected theme in Highland ethnography. I focus primarily on the history of the incorporation of one spirit cult ritual, rimbu, and its relationship to the other major spirit cult, kabit, and just how these two cults inter-relate with two major categories of exchange—the ceremonial pig kill (yasolu) and the more ‘mundane’ forms of exchange associated with such events as marriage and death. It is the structural parallels, differences and interconnections between these two exchange categories and the two ritual types which have guided much of the historical development of local social structure until colonisation. This has resulted in a substantial, though not necessarily stable, integration of ritual and exchange which has been ‘played out’ over the approximately fifteen-year periods between yasolu pig kills. I argue that it is this set of oppositions that provides the structural basis for different potentialities for male capacity. On occasion these may be so graphically distinct that they may be called differing social ontologies, different baselines for being and action. Different aspects of rimbu were adopted from around the turn of the twentieth century until colonisation some 50 years later when both kabit and rimbu were abandoned under mission pressure. However, to talk about the adoption of rimbu and the changes to Anganen social structure which it helped to produce as ‘pre-colonial’ history is misleading to the extent that much of the impetus for change was bound up in the efflorescence of trade caused by the Australian pearling industry in the Torres Strait. I call this period ‘ante-colonial’ in order to highlight the impact of the Australians and the irony that what the Australians indirectly helped create, rimbu as a central feature to Anganen social life, was destroyed with the direct colonial presence and missionisation.  相似文献   

5.
Pauli Murray’s lifelong fate was to be both ahead of her times concerning racism, heteropatriarchy, and class exploitation, yet largely behind the scenes within social movements that challenged these systems of oppression. As a truly independent African American feminist thinker, Murray’s accomplishments have long remained relatively unknown. This review essay analyses The Firebrand and the Lady and Jane Crow, two important biographies that constitute important additions to the growing corpus of scholarship on Murray’s life. These books lay a scholarly foundation for studying not only the life of this neglected African American feminist intellectual activist, but also how her ideas and actions catalyzed social change. Drawing upon contemporary anti-racist, feminist and intersectional frameworks, this essay analyses how both books draw upon race, class, gender, and sexuality as categories of analysis, yet place different analytical weight on these concepts.  相似文献   

6.
This study of immigrants’ integration in Israel centers on one major subjective parameter, namely the immigrant's identity. To explain it we explore a series of possible factors: demographic variables, economic status, and human and social capital characteristics. Three recent immigrant groups are examined: from Western countries, from the former Soviet Union (FSU), and from Ethiopia. These immigrants came to Israel during the last two decades from different societies, following different immigration circumstances and various motives.

The findings, based on the 2007 Ruppin survey data, point to the significant impact of the identity as perceived by veteran Israelis on the immigrants’ self-identity for the three groups under study. Also, different variables affect each of the immigrant groups. FSU immigrants behaved according to most of our hypotheses, whereas Western and Ethiopian immigrants did not. Findings are discussed in light of the debate on measuring and defining immigrants’ identity.  相似文献   

7.
Charlotte Duffee 《Bioethics》2020,34(7):695-702
Eric Cassell famously defined suffering as a person’s severe distress at a threat to their personal integrity. This article draws attention to some problems with the concept of distress in this theory. In particular, I argue that Cassell’s theory turns on distress but does not define it, which, in light of the complexity of distress, problematizes suffering in three ways: first, suffering becomes too equivocal to apply in at least some cases that Cassell nevertheless identifies as suffering; second, Cassell’s account does not explain what sort of experience suffering is, resulting in theoretical and practical difficulties in distinguishing it from other medical conditions; third, there is good reason to believe that, in medical contexts, ‘distress’ just means ‘suffering’ or some cognate concept not yet distinguished from it, rendering Cassell’s theory circular. I consider a rebuttal to my objections and reply, concluding that Cassell’s theory of suffering needs a definition of distress to settle what the nature of suffering really is.  相似文献   

8.
Waldinger's The Cross-Border Connection is a tour de force. Yet, this commentary describes ways in which his work can and should be amended to deepen and broaden the understanding of today's world on the move. It demonstrates how the understanding of immigration can be enhanced by a deepened sociological analysis of features that shape immigrant experiences, such as gender and pre-migration lived experiences and life perspectives so formed. It also demonstrates how the understanding of immigration can be enhanced by incorporating macro-transnational dynamics into the analysis, above and beyond the transnational local-level involvements on which Waldinger focuses. Immigrants’ homeland impact may be society-wide, indirect and unintended. The importance of each of these matters is illustrated with respect to immigration from the Global South to the Global North.  相似文献   

9.
The study aimed to investigate the soil-plant relationship by looking at knowledge levels of social media users. The study examined the relationship between the users’ characteristics and their knowledge on soil-plant relationship. Online survey was designed and distributed to gather the data. The number of response was received from 383 respondents where 375 participants provided completed information and the remaining eight responses were eliminated due to quality standards. The results show most of the participants (68.8%) are moderately depend on social media to acquire knowledge on soil-plant relationship and indicated “Twitter” as the highly utilized platform followed by the “Youtube”. Meanwhile, 48.8% of the participants indicated that social media have a high impact on their knowledge-based information on soil-plant relationship and agricultural contents. Inferential analysis shows there was a significant positive relationship (p < 0.01) between independent variables; Twitter, Youtube, Instagram, and Snapchat and the degree of trust on these platforms, and the level’s knowledge on soil-plant relationship (dependent variable). Only 13% of the variance accounted for the impact of social media on participants’ agricultural knowledge-base can be predicted from the combination of participants’ reliance on a set of social media platforms (Twitter, Instagram, Youtube, and Snapchat). The study revealed the trust and confidence of the users using social media on agricultural information/soil plant relationship had a medium effect in social and educational research.  相似文献   

10.
Entropy-related biodiversity indices deriving their conceptual basis from Shannon’s information theory have a long history of use in ecology for quantifying community structure and diversity. In addition, in the last two decades, numerous information–theoretical indices, such as the landscape dominance index, have been extensively applied to characterize landscape diversity in space and time. In this contribution, we offer a simple analytical relation between Pielou’s evenness J and landscape dominance D within the broader context of Hill’s parametric diversity family. Within this context, we recommend the use of Hill’s diversity number evenness E1,0 to overcome the shortcomings both of Pielou’s evenness J and the landscape dominance index D.  相似文献   

11.
‘Fire mosaics’ are often maintained in landscapes to promote successional diversity in vegetation with little understanding of how this will affect ecological processes in animal populations such as dispersal, social organization and re‐establishment. To investigate these processes, we conducted a replicated, spatiotemporal landscape genetics study of two Australian woodland lizard species [Amphibolurus norrisi (Agamidae) and Ctenotus atlas (Scincidae)]. Agamids have a more complex social and territory structure than skinks, so fire might have a greater impact on their population structure and thus genetic diversity. Genetic diversity increased with time since fire in C. atlas and decreased with time since fire in A. norrisi. For C. atlas, this might reflect its increasing population size after fire, but we could not detect increased gene flow that would reduce the loss of genetic diversity through genetic drift. Using landscape resistance analyses, we found no evidence that postfire habitat succession or topography affected gene flow in either species and we were unable to distinguish between survival and immigration as modes of postfire re‐establishment. In A. norrisi, we detected female‐biased dispersal, likely reflecting its territorial social structure and polygynous mating system. The increased genetic diversity in A. norrisi in recently burnt habitat might reflect a temporary disruption of its territoriality and increased male dispersal, a hypothesis that was supported with a simulation experiment. Our results suggest that the effects of disturbance on genetic diversity will be stronger for species with territorial social organization.  相似文献   

12.
Life‐history and pace‐of‐life syndrome theory predict that populations are comprised of individuals exhibiting different reproductive schedules and associated behavioural and physiological traits, optimized to prevailing social and environmental factors. Changing weather and social conditions provide in situ cues altering this life‐history optimality; nevertheless, few studies have considered how tactical, sex‐specific plasticity over an individual's lifespan varies in wild populations and influences population resilience. We examined the drivers of individual life‐history schedules using 31 years of trapping data and 28 years of pedigree for the European badger (Meles meles L.), a long‐lived, iteroparous, polygynandrous mammal that exhibits heterochrony in the timing of endocrinological puberty in male cubs. Our top model for the effects of environmental (social and weather) conditions during a badger's first year on pace‐of‐life explained <10% of variance in the ratio of fertility to age at first reproduction (F/α) and lifetime reproductive success. Conversely, sex ratio (SR) and sex‐specific density explained 52.8% (males) and 91.0% (females) of variance in adult F/α ratios relative to the long‐term population median F/α. Weather primarily affected the sexes at different life‐history stages, with energy constraints limiting the onset of male reproduction but playing a large role in female strategic energy allocation, particularly in relation to ongoing mean temperature increases. Furthermore, the effects of social factors on age of first reproduction and year‐to‐year reproductive success covaried differently with sex, likely due to sex‐specific responses to potential mate availability. For females, low same‐sex densities favoured early primiparity; for males, instead, up to 10% of yearlings successfully mated at high same‐sex densities. We observed substantial SR dynamism relating to differential mortality of life‐history strategists within the population, and propose that shifting ratios of ‘fast’ and ‘slow’ life‐history strategists contribute substantially to population dynamics and resilience to changing conditions.  相似文献   

13.
Jafari and Smith hypothesized that time during games may pass slower for the world’s best football player, Lionel Messi, from Argentina. This hypothesis leads to two questions: How can we explain such temporal paradox and how could this explain his dominant performances? Remarkably, the Argentinian’s case was preceded by the equally astonishing case of Wayne Gretzky: The Canadian considered ice hockey as a rather slow game and was the best player in the sport’s history. Whether Messi’s and Gretzky’s motor neurons fire faster, (inter)act differently or whether other mechanisms are at (inter)play warrants targeted research. A further explanation for such dominance of football and ice hockey, respectively, could be that both athletes “buy time”: To this end, automized motor skills may allow their predictive brains to make better use of time than other players to read the games and plan ahead. Deconstructing predictive minds of outperforming individuals like Gretzky and Messi could provide unique options to elucidate how differential time perception may make performances in athletes, and beyond, more swift and more efficient.  相似文献   

14.
ABSTRACT

Jennifer Lee and Min Zhou’s new book, The Asian American Achievement Paradox, revives Asian American scholarship from a period of relative stagnation and elevates the discussion from the morass of cultural essentialism. Its major contributions are to extensively articulate: (1) how much cultural explanations are actually class-based explanations and (2) how selective migration creates the conditions that promote social mobility. This book resolves empirical paradoxes in the scholarship and engages broader debates on race, immigration and inequality.  相似文献   

15.
Males are under different selective pressures than females, which results in differences in the physiology of the two sexes to maximize their fitness. In terms of immunity, males are typically considered as the ‘sicker sex’, where immunocompetence is reduced to favour increased reproductive output. However, male social Hymenoptera are also haploid and therefore lack allelic variation at the individual level, which can also lead to reduced immunocompetence. Over the last decade, several studies have provided evidence for a higher susceptibility to disease in males of social Hymenoptera, without clarifying whether this susceptibility was a direct consequence of their haploid condition or the result of a ‘live hard, die young’ overall evolutionary strategy. In the present study, we used an experimental approach of bacterial challenge to test the immune response of males and females in two species of social Hymenoptera (honey bees, Apis mellifera; paper wasps, Polistes dominula), where males show very different life‐history traits. Drones benefit from colony protection for most of their life, whereas P. dominula males leave their colonies and have to survive for weeks at leks. If the haploid condition is responsible for a higher susceptibility in males, we should expect a lower immune response in males of both species compared to females. Conversely, if the immunocompetence depends on the life‐history traits of males, an opposite trend is expected in males of the two species. Our results do not support the ‘haploid susceptibility hypothesis’ but are in accordance with the different life history of males from the two species. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 274–278.  相似文献   

16.
ABSTRACT

Background: The unpredictable, “on-call” component of the emergency services (ES) may be difficult to navigate in the context of domestic and work responsibilities, and especially difficult for women, given they tend to take on a greater household burden than do men. Our aim was to understand women’s experiences in the ES, particularly the impact of being on-call and related coping strategies.

Methods: Twenty-four women were recruited from two ES agencies in Australia. Participation involved a brief questionnaire and a 45–60-min interview. Interviews were recorded, and audio files were transcribed before analysis using nVIVO software.

Results: Interview data identified two major themes: impact and management. Women talked about the impact of on-call for themselves (e.g. disturbed? sleep, fatigue and the relentlessness of the role) but also discussed the, largely negative, impact for their family/household. In terms of management, support (family, social and work) and planning and preparation were identified as important in helping women manage their multiple roles in the context of on-call unpredictability.

Conclusion: The negative impacts of on-call work on women’s sleep supports existing quantitative and qualitative data in the broader on-call area. For those women with children, managing their care presents one of the biggest challenges to being able to manage the on-call component of their work. Future research should to focus on quantifying the impact of on-call for both men and women, particularly the “relentlessness” of the work identified in this study and whether this toll changes based on other factors such as experience, role or gender.  相似文献   

17.
This paper analyzes the impact that Lamarckian evolutionary theory had in the scientific community during the period between the advent of Zoological Philosophy and the publication Origin of Species. During these 50 years Lamarck’s model was a well known theory and it was discussed by the scientific community as a hypothesis to explain the changing nature of the fossil record throughout the history of Earth. Lamarck’s transmutation theory established the foundation of an evolutionary model introducing a new way to research in nature. Darwin’s selectionist theory was proposed in 1859 to explain the origin of species within this epistemological process. In this context, Charles Lyell’s Principles of Geology and Auguste Comte’s Cours de Philosophie Positive appear as two major works for the dissemination of Lamarck’s evolutionary ideology after the death of the French naturalist in 1829.  相似文献   

18.

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the most common neurodegenerative diseases worldwide. They are characterized by the loss of neurons and synapses in special parts of the central nervous system (CNS). There is no definitive treatment for AD and PD, but extensive studies are underway to identify the effective drugs which can slow the progression of these diseases by affecting the factors involved in their pathophysiology (i.e., aggregated proteins, neuroinflammation, and oxidative stress). Icariin, a natural compound isolated from Epimedii herba, is known because of its anti-inflammatory and anti-oxidant properties. In this regard, there are numerous studies indicating its potential as a natural compound against the progression of CNS disorders, such as neurodegenerative diseases. Therefore, this review aims to re-examine findings on the pharmacologic effects of icariin on factors involved in the pathophysiology of AD and PD.

  相似文献   

19.
Tor Engeström 《Ethnos》2013,78(1-2):64-69
’Cultural theory’, launched by social anthropologist Mary Douglas, has been highly influential in the inter‐disciplinary field concerned with the study of risk perception and risk communication. The theory derives from the grid‐group analyses that Douglas developed in the 1970s. Cultural theory aims to explain universal ‘cultural bias’ by way of a general typology of group formation and a concomitant cosmology or world view. This article critically examines cultural theory and the study of hazards as culturally construed phenomena.  相似文献   

20.
Ecological factors have a pervasive impact on animal population sizes and the structure of their social systems. In a number of ungulate species, predator pressure exerts a major influence on group size. Given that giraffe (Giraffa camelopardalis) live in an extremely flexible social system, and that breeding is nonseasonal, they are an ideal species for examining how ecological variables contribute to fluctuations in herd size. We present an analysis of 34 years of data on a population of Thornicroft’s giraffe (G. c. thornicrofti Lydekker 1911) that reveal how herd size changes with season and habitat. Sex differences in herd size were apparent, with bulls often travelling as singletons, whereas cows were generally observed with conspecifics. Herds were larger during the wet than dry season, but herd size changed in a parallel fashion across habitats. Giraffe herds were smaller in woodland and thicket areas than in open habitats, regardless of season. We suggest that the regular fluctuations in herd size among giraffe indicate a fission/fusion social system embedded within a larger social community. We conclude that changes in herd size among giraffe reflect a dynamic process regulated by individuals adjusting the number of associates based upon an interaction of foraging, reproductive, social and antipredator strategies.  相似文献   

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