首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Although awareness of end-of-life care is growing within the veterinary field and there appears to be consumer demand for these services, it is unclear exactly what caregivers know about end-of-life options for their companion animals. Are companion-animal caregivers aware of the range of options for their nonhuman animals? What do they value most highly for their nonhuman animals at the end of life? Answers to these and other related questions about caregiver perceptions are important because what they know about end-of-life care and how they approach decision-making for their companion animals will shape the kind of care an animal receives. This article presents the results of a large survey exploring companion-animal caregivers’ knowledge, attitudes, and beliefs about end-of-life care, including in-home euthanasia, hospice and palliative care, financial commitment to end-of-life care, insurance usage, and level of comfort in providing care (e.g., subcutaneous fluids) in the home.  相似文献   

2.
Cognition is defined as the processes by which animals collect, retain and use information from their environment to guide their behaviour. Thus cognition is essential in a wide range of behaviours, including foraging, avoiding predators and mating. Despite this pivotal role, the evolutionary processes shaping variation in cognitive performance among individuals in wild populations remain very poorly understood. Selection experiments in captivity suggest that cognitive traits can have substantial heritability and can undergo rapid evolution. However only a handful of studies have attempted to explore how cognition influences life‐history variation and fitness in the wild, and direct evidence for the action of natural or sexual selection on cognition is still lacking, reasons for which are diverse. Here we review the current literature with a view to: (i) highlighting the key practical and conceptual challenges faced by the field; (ii) describing how to define and measure cognitive traits in natural populations, and suggesting which species, populations and cognitive traits might be examined to greatest effect; emphasis is placed on selecting traits that are linked to functional behaviour; (iii) discussing how to deal with confounding factors such as personality and motivation in field as well as captive studies; (iv) describing how to measure and interpret relationships between cognitive performance, functional behaviour and fitness, offering some suggestions as to when and what kind of selection might be predicted; and (v) showing how an evolutionary ecological framework, more generally, along with innovative technologies has the potential to revolutionise the study of cognition in the wild. We conclude that the evolutionary ecology of cognition in wild populations is a rapidly expanding interdisciplinary field providing many opportunities for advancing the understanding of how cognitive abilities have evolved.  相似文献   

3.
The last decade has seen lots of studies on ‘animal personality’ (i.e. the study of consistent between‐individual behavioural differences). As timely and promising as this field is, its development has come with a diversity of research questions. As an unfortunate consequence, it now suffers from substantial confusion about what ‘animal personality’ is, and how relevant related research frameworks are. Here, we stress the current inconsistencies and sources of confusion pertaining to the field, and their consequences on terminology used and miscommunication between researchers. In an attempt to unravel and clarify the concepts underlying the field, we identify two distinct, but complementary, theory‐driven conceptual frameworks: the intra‐individual variability (IIV) approach and the life‐history (LH) approach, which we believe encompass the vast majority of existing ‘personality studies’. Finally, we argue in favour of theory‐driven studies of consistent behavioural differences and state that the integrative statistical properties of random regression models should not override the merit of alternative conceptual frameworks. We then provide brief guidelines and warnings for a parsimonious and sound use of terminology.  相似文献   

4.
5.
6.
7.
The study of infant social cognition is the study of how human infants acquire information about people. By examining infants’ sensory abilities and the stimulus characteristics of people, research can determine what information is available to infants from their social world. We can then consider what social environments are appropriate for infants of different ages. This paper examines the sociocognitive competencies of human infants during the first 6 months of their lives and asks how these competencies are functional in the daily social ecology of the human infant. Select examples of research with other species are used to illustrate how the adaptive significance of sociocognitive abilities could be more fruitfully explored in studies of human infancy. Lonnie R. Sherrod is Vice President for Program at the William T. Grant Foundation. Formerly, he was Assistant Dean at the Graduate Faculty of the New School for Social Research and before that, Staff Associate at the Social Science Research Council. He received a Ph.D. in Developmental Psychology from Yale University in 1978, an M.A. in Biology from the University of Rochester in 1974; and a B.A. in Zoology and Psychology from Duke University in 1972. He has taught at New York University and the New School and has published numerous articles and edited volumes on infant social cognition, on adolescence, and on child development from a life-span and biosocial perspective. Examples includeInfant Social Cognition (1981), edited with Michael Lamb;The Life Course and Human Development: Multidisciplinary Perspectives (1986), edited with Aage B. Sorensen and Franz E. Weinert; and “Changes in Children’s Social Lives and the Development of Social Understanding” authored with Judith Dunn (1988), in E.M. Hetherington, M. Perlmutter, and R. Lerner (eds).,Child Development in Life-Span Perspective.  相似文献   

8.
The preference‐performance hypothesis predicts that female insects should prefer to lay eggs in locations that enhance offspring performance. This study examines the choices of females regarding where to oviposit within plants, focusing on the hawkmoth Manduca sexta L. (Lepidoptera: Sphingidae) and its host Datura wrightii Regel (Solanaceae) in the southwestern USA. Smaller Datura leaves provide cooler microclimates for eggs (which may lead to faster embryonic development, shortening their exposure to egg predators) and more nitrogen for larvae. In contrast, large leaves reach temperatures that are stressfully high (which slows embryonic development) and provide less nitrogen for larvae. Thus, we would expect females to oviposit on small leaves. To examine whether leaf size influences female preference and offspring performance, we used laboratory and field studies to address the following questions. (1) On what size leaves do females typically oviposit? (2) Does the distribution of eggs in nature differ from that expected by chance? And (3) how does leaf size affect survival or growth of eggs and larvae? We find that oviposition choices of females do not lead to the highest probability of offspring survival. Females lay eggs on larger leaves, likely due to the greater accessibility of those leaves; however, eggs are more likely to hatch on small leaves. Larvae grow faster on large leaves, but larvae are also surprisingly mobile, suggesting that the consequences of oviposition site are minor once eggs have hatched. Larval mobility was seen only in the field, not in the laboratory, emphasizing the importance of field studies for predicting real‐world performance. Although females' leaf choices are potentially risky for eggs, the threats of high temperature and predation may vary sufficiently in space and time that there is no consistent selection for strong preferences. Furthermore, the fitness consequences for eggs and larvae largely offset each other and offspring are sufficiently mobile to cope with the conditions where they are laid.  相似文献   

9.
Implementation of existing ethical guidelines for international collaborative medical and health research is still largely controversial in sub‐Saharan Africa for two major reasons: One, they are seen as foreign and allegedly inconsistent with what has been described as an ‘African worldview’, hence, demand for their strict implementations reeks of ‘bioethical imperialism’. Two, they have other discernible inadequacies – lack of sufficient detail, apparent as well as real ambiguities, vagueness and contradictions. Similar charges exist(ed) in other non‐Western societies. Consequently, these guidelines have been correctly judged as an inadequate response to the complex and ever shifting dilemmas met by researchers and research regulators in the field. This paper proposes a framework for effective implementation of existing guidelines without much worry about bioethical imperialism and other inadequacies. This framework is proposed using an analogy of Legal Realism, specifically its key assertions on how, in reality, judicial systems operate using general legal rules to settle specific cases. Legal realists assert that in judicial decision‐making, general legal rules do not totally dictate court decisions in specific cases. This analogy is used to coin a new term, ‘Bioethical Realism.’ The framework suggests that local Research Ethics Committees ought to be construed as analogues of judicial courts with the resulting implications. Consequently, just like legal rules are general rules that do not always dictate court decisions, similarly international bioethical guidelines are general ethical rules that should not always dictate local RECs’ decisions and such decisions (ought to) enjoy considerable immunity from outsiders.  相似文献   

10.
During four decades (1960–1990s), the conceptualization and experimental design of studies in kin recognition relied on work with multicellular eukaryotes, particularly Unikonta (including invertebrates and vertebrates) and some Bikonta (including plants). This pioneering research had an animal behavior approach. During the 2000s, work on taxa‐, clone‐ and kin‐discrimination and recognition in protists produced genetic and molecular evidence that unicellular organisms (e.g. Saccharomyces, Dictyostelium, Polysphondylium, Tetrahymena, Entamoeba and Plasmodium) could distinguish between same (self or clone) and different (diverse clones), as well as among conspecifics of close or distant genetic relatedness. Here, we discuss some of the research on the genetics of kin discrimination/recognition and highlight the scientific progress made by switching emphasis from investigating multicellular to unicellular systems (and backwards). We document how studies with protists are helping us to understand the microscopic, cellular origins and evolution of the mechanisms of kin discrimination/recognition and their significance for the advent of multicellularity. We emphasize that because protists are among the most ancient organisms on Earth, belong to multiple taxonomic groups and occupy all environments, they can be central to reexamining traditional hypotheses in the field of kin recognition, reformulating concepts, and generating new knowledge.  相似文献   

11.
Can suffering in non‐human animals be studied scientifically? Apart from verbal reports of subjective feelings, which are uniquely human, I argue that it is possible to study the negative emotions we refer to as suffering by the same methods we use in ourselves. In particular, by asking animals what they find positively and negatively reinforcing (what they want and do not want), we can define positive and negative emotional states. Such emotional states may or may not be accompanied by subjective feelings but fortunately it is not necessary to solve the problem of consciousness to construct a scientific study of suffering and welfare. Improvements in animal welfare can be based on the answers to two questions: Q1: Will it improve animal health? and Q2: Will it give the animals something they want? This apparently simple formulation has the advantage of capturing what most people mean by ‘improving welfare’ and so halting a potentially dangerous split between scientific and non‐scientific definitions of welfare. It can also be used to validate other controversial approaches to welfare such as naturalness, stereotypies, physiological and biochemical measures. Health and what animals want are thus not just two of many measures of welfare. They provide the definition of welfare against which others can be validated. They also tell us what research we have to do and how we can judge whether welfare of animals has been genuinely improved. What is important, however, is for this research to be done in situ so that it is directly applicable to the real world of farming, the sea or an animal’s wild habitat. It is here that ethology can make major contributions.  相似文献   

12.
A traditional view of cognition is that it involves an internal process that represents, tracks or predicts an external process. This is not a general characteristic of all complex neural processing or feedback control, but rather implies specific forms of processing giving rise to specific behavioural capabilities. In this paper, I will review the evidence for such capabilities in insect navigation and learning. Do insects know where they are, or do they only know what to do? Do they learn what stimuli mean, or do they only learn how to behave?  相似文献   

13.
Evolutionary biologists have long been fascinated by extravagant male traits that abound across the animal kingdom and yet convey no apparent benefits to survival. From isopods to elephants, from armaments to ornaments, researchers have spent decades studying male–male competition and female mate choice in an effort to understand the significance of these secondary sexual characteristics. Among socially monogamous species, a frequently proposed explanation for the existence of male ornaments is that they are indicators of male genetic quality subject to female extra‐pair mate choice. However, despite over two decades of extensive research into extra‐pair paternity (EPP), the evidence that females actually choose more ornamented extra‐pair sires is surprisingly scant. Consequently, whether EPP and female choice have contributed to the evolution of male ornaments in socially monogamous species, and what fitness benefits (if any) they signal to females, remains unclear. Progress in this field has been hampered by the challenge of dissociating clear female choice for ornamentation from confounding factors. In this issue of Molecular Ecology, Whittingham & Dunn (2016) use an experimental approach in a bird species with very high rates of EPP to tease apart these correlative effects. In doing so, they demonstrate clearly that male ornamentation is subject to female extra‐pair mate choice. Their findings further suggest that EPP can be adaptive for females, and represent an important step forward in validating the role of EPP as an evolutionary driver of ornamental elaboration in socially monogamous species.  相似文献   

14.
A traditional view of cognition is that it involves an internal process that represents, tracks or predicts an external process. This is not a general characteristic of all complex neural processing or feedback control, but rather implies specific forms of processing giving rise to specific behavioural capabilities. In this paper, I will review the evidence for such capabilities in insect navigation and learning. Do insects know where they are, or do they only know what to do? Do they learn what stimuli mean, or do they only learn how to behave?  相似文献   

15.
Abstract

Allelopathy is defined as the suppression of any aspect of growth and/or development of one plant by another through the release of chemical compounds. Although allelopathic interference has been demonstrated many times using in vitro experiments, few studies have clearly demonstrated allelopathy in natural settings. This difficulty reflects the complexity in examining and demonstrating allelopathic interactions under field conditions. In this paper we address a number of issues related to the complexity of allelopathic interference in higher plants: These are: (i) is a demonstrated pattern or zone of inhibition important in documenting allelopathy? (ii) is it ecologically relevant to explain the allelopathic potential of a species based on a single bioactive chemical? (iii) what is the significance of the various modes of allelochemical release from the plant into the environment? (iv) do soil characteristics clearly influence allelopathic activity? (v) is it necessary to exclude other plant interference mechanisms?, and (vi) how can new achievements in allelopathy research aid in solving problems related to relevant ecological issues encountered in research conducted upon natural systems and agroecosystems? A greater knowledge of plant interactions in ecologically relevant environments, as well as the study of biochemical pathways, will enhance our understanding of the role of allelopathy in agricultural and natural settings. In addition, novel findings related to the relevant enzymes and genes involved in production of putative allelochemicals, allelochemical persistence in the rhizosphere, the molecular target sites of allelochemicals in sensitive plant species and the influence of allelochemicals upon other organisms will likely lead to enhanced utilization of natural products for pest management or as pharmaceuticals and nutraceuticals. This review will address these recent findings, as well as the major challenges which continue to influence the outcomes of allelopathy research.  相似文献   

16.
This article analyzes a number of recently published autobiographies by leading participants in the Human Genome Project (HGP), in order to determine to what extent they may further our understanding of the history, scientific significance and societal impact of this major research endeavor. Notably, I will focus on three publications that fall under this heading, namely The common thread by John Sulston (2002/2003), The language of God (2006) by Francis Collins and A life decoded by Craig Venter (2007).1 Sulston's autobiography was co-authored by science writer Georgina Ferry. What may we learn from these autobiographical sources about the dynamics of scientific change? What is their added value in understanding science in general and the HGP in particular? These questions will be elaborated in three directions: on the level of knowledge (epistemology), power (politics) and the Self (ethics). On the epistemological level, genomics is often presented as a paradigm shift in the life sciences, a tremendous up-scaling of research, an “informatization” of life. Autobiographies may reveal how this shift – usually discussed in more general terms from a philosophy of science or science studies perspective – manifests itself on an individual scale, on a micro-epistemological level. On the political level, autobiographies may inform us about the micro-politics of scientific change. Finally, on the level of Self, autobiographies may allow us to analyze how researchers, through practices of Self, are actively engaged in constituting themselves as responsible subjects in the face of unpredictable dynamics and unforeseen dilemmas.  相似文献   

17.
When exploiting the environment, animals have to discriminate, track, and integrate salient spatial cues to navigate and identify goal sites. Actually, they have to know what can be found (e.g. what fruit), where (e.g. on which tree) and when (in what season or moment of the year). This is very relevant for primate species as they often live in seasonal and relatively unpredictable environments such as tropical forests. Here, we review and compare different approaches used to investigate primate spatial foraging strategies: from direct observations of wild primates to predictions from statistical simulations, including experimental approaches on both captive and wild primates, and experiments in captivity using virtual reality technology. Within this framework, most of these studies converge to show that many primate species can (i) remember the location of most of food resources well, and (ii) often seem to have a goal‐oriented path towards spatially permanent resources. Overall, primates likely use mental maps to plan different foraging strategies to enhance their fitness. The majority of studies suggest that they may organise spatial information on food resources into topological maps: they use landmarks to navigate and encode local spatial information with regard to direction and distance. Even though these studies were able to show that primates can remember food quality (what) and its location (where), still very little is known on how they incorporate the temporal knowledge of available food (when). Future studies should attempt to increase our understanding of the potential of primates to learn temporal patterns and how both socio‐ecological differences among species and their cognitive abilities influence such behavioural strategies.  相似文献   

18.
C. C. Horvitz 《Oecologia》1981,51(1):47-52
Summary The evolutionary effects of a tropical ant-seed interaction are examined by posing questions about the fate of Calathea seeds carried by neotropical ants. Where do ants take seeds and what do they do with them? How do ant behaviors affect seed germination? Treatment of seeds by ants is determined by a series of seed-fate trials in captive colonies. There is no evidence of seed predation by ants. Odontomachus laticeps, Pachycondyla spp, and Solenopsis geminata rapidly displace seeds to ant nests, determine the microsites of seeds, and remove the seed arils for food. The seed arils are rich in lipids. The effects on germination of microsite selection and aril removal are quantitatively evaluated. Seeds which are immediately taken to a consistently moist spot germinate readily; 72% germinate, with a mean germination speed of 29 days. For such seeds aril removal does not significantly affect germination. In contrast, seeds which experience a delay before encountering appropriate germination conditions seem to exhibit an induced dormancy (sensu, Harper 1977) and a lower germination percentage. They take longer to germinate (up to 85 days) even after conditions become appropriate. It appears that their germination is enhanced by aril removal, which may act as an environmental cue to break dormancy. Such a mechanism would indicate that ant-handling of seeds is predictive of favorable conditions for seedling growth and establishment. The exact nature of such conditions and the effects on plant population dynamics remain to be seen.  相似文献   

19.
《Biomarkers》2013,18(1):12-19
The inhibitory effects on esterases and phospholipase A2 (PLA2) in the freshwater rotifer Euchlanis dilatata, native to Mexico, were assessed by fluorimetry after in vivo exposure (30?min) in laboratory conditions to sublethal concentrations of metals and pesticides. EC50 values for esterases ranged from 7.9?×?10?7 for DDT to 61.9 μg l?1 for methyl parathion, while corresponding values for PLA2 ranged from 0.96?×?10?6 for mercury to 69.2 μg l?1 for lead. These enzyme systems in E. dilatata are very sensitive to the tested agents and suggest they would be suitable biomarkers. However, sensitivity to other environmental contaminants should be investigated in laboratory conditions and field studies to assess their potential as environmental biomarkers.  相似文献   

20.
The paper examines Marcello Barbieri’s (2007) Introduction to Biosemiotics. Highlighting debate within the biosemiotic community, it focuses on what the volume offers to those who explain human intellect in relation to what Turing called our ‘physical powers.’ In scrutinising the basis of world-modelling, parallels and contrasts are drawn with other work on embodied-embedded cognition. Models dominate biology. Is this a qualitative fact or does it point to biomechanisms? In evaluating the 18 contributions, it is suggested that the answers will shape the field. First, they will decide if biochemistry and explanatory reduction can be synergised by biosemantics. Second, they will show if our intellectual powers arise from biology. Does thinking use—not a language faculty—but what Marko? and colleagues call semiosis by the living? Resolution of such issues, it is suggested, can change how we view cognition. Above all, if the biomechanists win the day, cultural models can be regarded as extending natural meaning. On such a view, biomechanisms prompt us to act and perceive as we model our own natural models. This fits Craik’s vision: intellect gives us the alphanumerical ‘symbols’ that allow thoughts to have objective validity. For the biomechanist, this is explained—not by brains alone—but, rather, by acting under the constraints of historically extended sensoria.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号