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SAMIA HURST 《Bioethics》2010,24(8):439-444
Uncertainty as to how we should articulate empirical data and normative reasoning seems to underlie most difficulties regarding the ‘empirical turn’ in bioethics. This article examines three different ways in which we could understand ‘empirical turn’. Using real facts in normative reasoning is trivial and would not represent a ‘turn’. Becoming an empirical discipline through a shift to the social and neurosciences would be a turn away from normative thinking, which we should not take. Conducting empirical research to inform normative reasoning is the usual meaning given to the term ‘empirical turn’. In this sense, however, the turn is incomplete. Bioethics has imported methodological tools from empirical disciplines, but too often it has not imported the standards to which researchers in these disciplines are held. Integrating empirical and normative approaches also represents true added difficulties. Addressing these issues from the standpoint of debates on the fact‐value distinction can cloud very real methodological concerns by displacing the debate to a level of abstraction where they need not be apparent. Ideally, empirical research in bioethics should meet standards for empirical and normative validity similar to those used in the source disciplines for these methods, and articulate these aspects clearly and appropriately. More modestly, criteria to ensure that none of these standards are completely left aside would improve the quality of empirical bioethics research and partly clear the air of critiques addressing its theoretical justification, when its rigour in the particularly difficult context of interdisciplinarity is what should be at stake. 相似文献
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Heuser J 《Biology of the cell / under the auspices of the European Cell Biology Organization》2002,94(9):561-596
Keith Porter culminated his stellar career as the founding father of biological electron microscopy by acquiring, in the late 1970s, a high-voltage electron microscope (HVEM). With this magnificent instrument he examined whole-mounts of cultured cells, and perceived within them a structured cytoplasmic matrix he named the "microtrabecular lattice". Over the next decade Porter published a series of studies, together with a team of outstanding young colleagues, which elaborated his broader "microtrabecular concept." This concept posited that microtrabeculae were real physical entities that represented the fundamental organization the cytoplasm, and that they were the physical basis of cytoplasmic motility and of cell-shape determination. The present review presents Porter's original images of microtrabeculae, after conversion to a more interpretable "digital-anaglyph" form, and discusses the rise and fall of the microtrabecular concept. Further, it explains how the HVEM images of microtrabeculae finally came to be considered as an artifact of the preparative methods Porter used to prepare whole cells for HVEM. Still, Keith's "microtrabecular concept" foretold of our current appreciation of the complexity and pervasiveness of the cytoskeleton, which has now been found by more modern methods of EM to actually be the fundamental organizing principle of the cytoplasmic matrix. During the impending eclipse of Porter's microtrabecular concept in the late 1980s, many of Keith's colleagues fondly described the cell as being filled, not with protoplasm, but with "Porterplasm." Despite the fact that Keith's view was clouded by the methods of his time, it would be fitting and apt to retain this name, still today, for the ordered matrix of cytoskeletal macromolecules that exists in the living cell. In the end, the story of what happened to Porter's microtrabecular concept should be an object lesson in scientific hubris that should humble and inform all of us in cell biology, even today--particularly when we begin to think that our most recent methods and observations are achieving "the last word". 相似文献
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William R. A. Brown Zheng‐yao Xu 《BioEssays : news and reviews in molecular, cellular and developmental biology》2009,31(2):228-236
Kinetochores can form and be maintained on DNA sequences that are normally non‐centromeric. The existence of these so‐called neo‐centromeres has posed the problem as to the nature of the epigenetic mechanisms that maintain the centromere. Here we highlight results that indicate that the amount of CENP‐A at human centromeres is tightly regulated. It is also known that kinetochore assembly requires sister chromatid cohesion at mitosis. We therefore suggest that separation or stretching between the sister chromatids at metaphase reciprocally determines the amount of centromere assembly in the subsequent interphase. This reciprocal relationship forms the basis of a negative feedback loop that could precisely control the amount of CENP‐A and faithfully maintain the presence of a kinetochore over many cell divisions. We describe how the feedback loop would work, propose how it could be tested experimentally and suggest possible components of its mechanism. 相似文献
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Entomophilous flowers form the food resources for insect pollinators. Many pollinator species forage at the landscape scale and depend on floral resources that are highly variable in space and time. We present a general model approach in which the floral resources of plant communities are estimated by the floral phenology and the cover of entomophilous plant species. We applied this landscape model in a case study for three landscape sections (1.5–2.2 km2) with strongly differing land-use patterns. The comparison between a conservation area and two agricultural landscapes shows extreme differences in the quantities and in the course of floral resources.
In a stepwise simplification of the landscape model we tested the effects of input data with lower spatio-temporal resolution. Even if input data for floral phenology and vegetation have a low resolution, the landscape model allows a ranking of landscape-specific floral resource potentials. The results of the case study encourage the use of landscape models to estimate floral resource potentials. The assessment of floral resource potentials may help to define this essential landscape quality for evaluation in practical nature conservation. 相似文献
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Mitochondria and peroxisomes: Are the ‘Big Brother’ and the ‘Little Sister’ closer than assumed? 总被引:5,自引:0,他引:5
Schrader M Yoon Y 《BioEssays : news and reviews in molecular, cellular and developmental biology》2007,29(11):1105-1114
Mitochondria and peroxisomes are essential subcellular organelles in mammals. Despite obvious differences, both organelles display certain morphological and functional similarities. Recent studies have elucidated that these highly dynamic and plastic organelles share components of their division machinery. Mitochondria and peroxisomes are metabolically linked organelles, which are cooperating and cross-talking. This review addresses the dynamics and division of mitochondria and peroxisomes as well as their functional similarities to provide insight as to why these organelles share the fission machinery in evolutionary aspects. 相似文献
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Waters JM 《Molecular ecology》2011,20(21):4388-4394
Phylogeographic and evolutionary research programmes have successfully elucidated compelling genetic signatures of earth history. Particularly influential achievements include the demonstration of postglacial recolonization patterns for high-latitude taxa and phylogenetic demonstration of the 'progression rule' along oceanic island chains such as Hawaii. While both of these major biogeographic patterns clearly rely on rapid dispersal over long distances, their phylogeographic detection also apparently relies on the competitive exclusion of secondary dispersers. Such exclusion could occur either between or within species and might reflect fitness differences between lineages or, alternatively, neutral demographic processes (e.g. 'high-density blocking'). Regardless, such spatial genetic patterns would be rapidly eroded were it not for the failure of subsequent dispersers to contribute genetically to newly colonized populations. In addition to its role in revealing colonization patterns, competitive exclusion may also explain the maintenance of historic phylogeographic disjunctions long after the original physical barriers to dispersal have ceased to exist. Additionally, some of the most persuasive evidence of competitive exclusion comes from studies of anthropogenic extinction, where surviving lineages have subsequently expanded their ranges, apparently benefitting from the demise of their prehistoric sisters. Broadly, these biogeographic paradigms are united by the 'disconnect' between dispersal and colonization success, the latter being heavily influenced by inter- and intraspecific competition. Despite its apparent importance, such exclusion (especially within species) has received virtually no attention in the phylogeographic literature. Future studies should aim to test directly for the role of competitive exclusion in constraining the biogeography of highly dispersive taxa. 相似文献
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The Dutch case of Brongersma presents novel challenges to the definition and evaluation of voluntary euthanasia since it involved a doctor assisting the suicide of an individual who was (merely?) ‘tired of life’. Legal officials had called on the courts to ‘set a principled boundary’, excluding such cases from the scope of permissible voluntary euthanasia, but they arguably failed. This failure is explicable, however, since the case seems justifiable by reference to the two major principles in favour of that practice, respect for autonomy and beneficence. Ultimately, it will be argued that those proponents of voluntary euthanasia who are wary of its use in such circumstances may need to draw upon ‘practical’ objections, in order to erect an otherwise arbitrary perimeter. Furthermore, it will be suggested that the issues raised by the case are not peculiarly Dutch in nature and that, therefore, there are lessons here for other jurisdictions too. 相似文献
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The phrase, “T. rangeli is pathogenic to its insect vector,” is commonly found in peer‐reviewed publications on the matter, such that it has become the orthodox view of this interaction. In a literature survey, we identified over 20 papers with almost the exact phrase and several others alluding to it. The idea is of particular importance in triatomine population dynamics and the study of vector‐borne T. cruzi transmission, as it could mean that triatomines infected with T. rangeli have lower fitness than uninfected insects. Trypanosoma rangeli pathogenicity was first observed in a series of studies carried out over fifty years ago using the triatomine species Rhodnius prolixus. However, there are few studies of the effect of T. rangeli on its other vector species, and several of the studies were carried out with R. prolixus under non‐physiological conditions. Here, we re‐evaluate the published studies that led to the conclusion that T. rangeli is pathogenic to its vector, to determine whether or not this indeed is the “true” effect of T. rangeli on its triatomine vector. 相似文献
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Guntram Weithoff 《Freshwater Biology》2003,48(9):1669-1675
1. This is a discussion of the applicability to the phytoplankton of the concepts of ‘plant functional types’ (PFTs) and ‘functional diversity’ (FD), which originated in terrestrial plant ecology. 2. Functional traits driving the performance of phytoplankton species reflect important processes such as growth, sedimentation, grazing losses and nutrient acquisition. 3. This paper presents an objective, mathematical way of assigning PFTs and measuring FD. Ecologists can use this new approach to investigate general hypotheses [e.g. the intermediate disturbance hypothesis (IDH), the insurance hypothesis and synchronicity phenomena] as, for example, in its original formulation the IDH makes its predictions based on FD rather than species diversity. 相似文献
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Dickenson D 《Bioethics》2006,20(3):115-124
Prominent international and national ethics commissions such as the UNESCO International Bioethics Committee rarely achieve anything remotely resembling gender equality, although local research and clinical ethics committees are somewhat more egalitarian. Under‐representation of women is particularly troubling when the subject matter of modern bioethics so disproportionately concerns women’s bodies, and when such committees claim to derive ‘universal’ standards. Are women missing from many ethics committees because of relatively straightforward, if discriminatory, demographic factors? Or are the methods of analysis and styles of ethics to which these bodies are committed somehow ‘anti‐female’? It has been argued, for example, that there is a ‘different voice’ in ethical reasoning, not confined to women but more representative of female experience. Similarly, some feminist writers, such as Evelyn Fox Keller and Donna Haraway, have asked difficult epistemological questions about the dominant ‘masculine paradigm’ in science. Perhaps the dominant paradigm in ethics committee deliberation is similarly gendered? This article provides a preliminary survey of women’s representation on ethics committees in eastern and western Europe, a critical analysis of the supposed ‘masculinism’ of the principlist approach, and a case example in which a ‘different voice’ did indeed make a difference. 相似文献
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Solrun Williksen‐Bakker 《The Australian journal of anthropology》2004,15(2):198-212
The focus of the paper is an examination of the relevance of the traditional concept mãduã for an understanding of Fijian culture, particularly in the context of modern business enterprise. The concept represents a multitude of subtle as well as clearly displayed emotions and attitudes. Though mãduã is especially relevant in situations where Fijian values are centre stage, the view put forward here is that the associated expressions and bodily postures are also relevant in modern urban contexts, where perhaps one might otherwise expect them to be discarded or at least toned down. In public discourse in Fiji, where the theme of Fijian participation in both education and business is constantly commented on and discussed, a new notion is identified, namely ‘silence’. The author suggests that it may to some degree replace and encompass mãduã The prime concern of the article, however, is to bring to the fore reflections by Fijians themselves on existential dilemmas, one of which is about how to live with mãduã in the modern context. 相似文献
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What can we Learn from Patients’ Ethical Thinking about the right ‘not to know’ in Genomics? Lessons from Cancer Genetic Testing for Genetic Counselling 下载免费PDF全文
Lorraine Cowley 《Bioethics》2016,30(8):628-635
This article is based on a qualitative empirical project about a distinct kinship group who were among the first identified internationally as having a genetic susceptibility to cancer (Lynch Syndrome). 50 were invited to participate (42 were tested; eight declined genetic testing). 15, who had all accepted testing, were interviewed. They form a unique case study. This study aimed to explore interviewees’ experiences of genetic testing and how these influenced their family relationships. A key finding was that participants framed the decision to be tested as ‘common sense’; the idea of choice around the decision was negated and replaced by a moral imperative to be tested. Those who did not follow ‘common sense’ were judged to be imprudent. Family members who declined testing were discussed negatively by participants. The article addresses what is ethically problematic about how test decliners were discussed and whether these ethical concerns extend to others who are offered genetic testing. Discussions showed that genetic testing was viewed as both an autonomous choice and a responsibility. Yet the apparent conflict between the right to autonomy and the moral imperative of responsibility allowed participants to defend test decliners’ decisions by expressing a preference for or defending choice over responsibility. The ‘right not to know’ seemed an important moral construct to help ethically manage unpopular decisions made by close family who declined testing. In light of this research, the erosion of the ‘right not to know’ in the genomic age could have subtle yet profound consequences for family relationships. 相似文献
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Miller RA 《Aging cell》2004,3(2):47-51
Organism envy afflicts most researchers who work on aging in mice; how frustrating it is to see the worm and fly biologists nail down milestone after milestone, citation after citation! Surely genetic trickery can produce mice that age in a comparable jiffy? Alas, our near‐total ignorance of what times the aging process makes it hard to guess what genes to tweak, if indeed aging can be mimicked a presto. Building a case that a given short‐lived mutant ages quickly is a steep and thorny path, requiring more than just plucking a symptom here and there from a list of things that sometimes go wrong in old people or old mice. The hallmark of aging is that a lot goes wrong more or less at the same time, in 2‐year‐old mice, 10‐year‐old dogs and 70‐year‐old people. Finding ways to damage one or two systems in a 6‐week or 6‐month‐old mouse is not too hard to do, but the implications of such studies for improved understanding of aging per se are at best indirect and at worst imaginary and distracting. 相似文献
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JUSSI NIEMELÄ 《Bioethics》2011,25(5):267-279
The advances in biotechnology have given rise to a discussion concerning the strong emotional reaction expressed by the public towards biotechnological innovations. This reaction has been named the ‘Yuck‐factor’ by several theorists of bioethics. Leon Kass, the former chairman of the President's council on bioethics, has appraised this public reaction as ‘an emotional expression of deep wisdom, beyond reason's power fully to articulate it’. 1 Similar arguments have been forwarded by the Catholic Church, several Protestant denominations and the Pro‐Life movement. Several bioethicists have, however, opposed the idea of a disgust‐based morality. 2 Recent findings in cognitive science support the view that the strong negative emotions people often experience when faced with biotechnological ideas are not expressions of inner wisdom. The negative emotions may rather be the result of a cognitive violation the biotechnological innovations easily cause. Due to their evolutionary background, people have certain automatic and quick cognitive tendencies routinely used for categorizing and reasoning about nature, usually termed ‘folk biology’. Biotechnological processes like hybridisation and cloning clearly violate several of the cognitive rules people naturally apply for the explanation and categorization of their natural environment. As the cognitive tendencies routinely applied to the explanation of biological world are violated, an emotional response of fear, disgust and of something unnatural being underway is easily provoked. It is suggested in this paper that the reason behind the Yuck‐factor is not a deep inner wisdom, but a violation of natural human cognitive tendencies concerning the biological world. 相似文献