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1.
The Dodo Raphus cucullatus, a giant flightless pigeon endemic to Mauritius, became extinct in the late seventeenth century, and so rapid was the birds’ disappearance, that by the beginning of the nineteenth century even its very existence was questioned. Only four specimens were then recorded in European museums, of which the most famous was the Tradescant or Oxford Dodo, now in the Oxford University Museum of Natural History. It comprised the head and one foot, and unique soft tissue in the form of skin and traces of feathers. The history of this specimen is reviewed, including the still unresolved question of how it came to Britain, and we provide evidence to show that it was stuffed but probably never mounted. The changes of ownership, and its cataloguing and curation in the different museums are also described, along with its varying roles in entertainment, education and research from the earliest years until the nineteenth century. This is part one of a two-part article; the second deals with the Tradescant Dodo from its dissection in the 1840s until the present day.  相似文献   

2.
Today, the Dodo is the most famous species known to have been driven to extinction through human activity. However, it disappeared over a century before Cuvier demonstrated the reality of extinction, and was only one of a huge number of species that died out following early European expansion around the globe. Unlike many other now-extinct Mascarene species, the Dodo's decline and disappearance was not documented by contemporary observers. Repeated settlement changes on Mauritius during the seventeenth century led to protracted ‘cultural amnesia’ over its very existence, and it was widely regarded as mythical by European scientists into the nineteenth century. A series of scientific and socio-cultural hurdles, which all had to be overcome before a given species could be widely appreciated by the general public as an icon of human-caused extinction, are identified and assessed in order to understand how the Dodo returned from scientific death and achieved its tremendous posthumous celebrity. This review indicates that although some ecological and evolutionary factors may have given the Dodo an increased chance of becoming famous, these factors are offset by a much greater series of serendipitous events, emphasising the importance of contingence and the fundamental lack of inevitability in historical processes.

The dodo was (perverse distinction) Immortalized by his extinction  相似文献   

3.
Mammals arousing from hibernation display pronounced regional heterothermy, where the thoracic and head regions warm faster than the abdominal and hindlimb regions. We used laser-Doppler flowmetry to measure peripheral hind foot blood flow during hibernation and arousal and gamma imaging of technetium-labeled albumin to measure whole blood volume distribution in hamsters arousing from hibernation. It was discovered that the hibernating hamster responds to physical but not to sound or hypercapnic stimulation with rapid, 73% reduction of hind foot blood flow. Hind foot blood flow vasoconstriction was maintained from the onset of arousal until late in arousal when rectal temperature was rapidly increased. alpha-Adrenergic blockade early in arousal increased hind foot blood flow by 700%, suggesting that vasoconstriction was mediated by activation of sympathetic tone. Gamma imaging revealed that, by the early phase of arousal from hibernation, the blood volume of the body below the liver is greatly reduced, whereas blood volumes of the thorax and head are much greater than corresponding volumes in anesthetized hamsters. As arousal progresses and cardiac activity increases and regional heterothermy develops, this regional blood volume distribution is largely maintained; however, blood volume slowly decreases in the thoracic region and slowly increases in the shoulder and head regions. The rapid increase in rectal temperature, characteristic of mid- to late- arousal phases, is probably mediated, in part, by reduction of adrenergic tone on abdominal and hindlimb vasculature. Warm blood then moves into the hind body, produces an increase in temperature, blood flow, and blood volume in the hind body and compensatory reductions of blood volume in the neck, head, and thoracic regions.  相似文献   

4.
In the freshwater coelenterate, hydra, asexual reproduction via budding occurs at the base of the gastric region about two-thirds of the distance from the head to the foot. Developmental gradients of head and foot activation and inhibition originating from these organizing centers have long been assumed to control budding in hydra. Much has been learned over the years about these developmental gradients and axial pattern formation, and in particular, the inhibitory influence of the head on budding is well documented. However, understanding of the role of the foot and potential interactions between the foot, bud, and head patterning systems is lacking. The purpose of this study was to investigate the role of the foot in the initiation of new axis formation during budding by manipulating the foot and monitoring effects on the onset of first bud evagination and the time necessary to reach the 50% budding point. Several experimental situations were examined: the lower peduncle and foot (PF) were injured or removed, a second PF was laterally grafted onto animals either basally (below the budding zone) or apically (above the budding zone), or both the head and PF were removed simultaneously. When the PF was injured or removed, the onset of first bud evagination was delayed and/or the time until the 50% budding point was reached was longer. The effects were more pronounced when the manipulation was performed closer to the anticipated onset of budding. When PF tissue was doubled, precocious bud evagination was induced, regardless of graft location. Removal of the PF at the same time as decapitation reduced the inductive effect of decapitation on bud evagination. These results are discussed in light of potential signals from the foot or interactions between the foot and head patterning systems that might influence bud axis initiation.  相似文献   

5.
The discovery of the first fossil Dodo remains in the Mare aux Songes marsh, Mauritius, in 1865 resulted in a race to publish on the Dodo's post-cranial anatomy. George Clark, probable discoverer of the fossil site, sent consignments of bones initially to Richard Owen (British Museum), and subsequently to Alfred Newton, Cambridge, via Alfred's brother Edward, who was stationed on Mauritius. After receiving the first consignment, Owen intercepted material intended for Alfred, and abused his position to forestall any complaints from Alfred. Owen published on the Dodo first, while Clark was financially rewarded, but Clark's ensuing arguments over the site discovery with railway engineer, Harry Higginson, and attempt to cover up the abundance of Dodo bones, thus keeping prices high, concluded in a bitter rivalry that was never resolved between Owen and the Newton brothers.  相似文献   

6.
本文通过测量猕猴海南亚种(Macaca mulatta brevicaudus)的形态学指标,讨论了该亚种的形态特点及其适应性意义。于2015年7-8月在海南省陵水县猕猴自然保护区对8个群的猕猴进行了形态学指标测量,共测得253只个体的体质量,132只个体的头长、顶臀长、尾长、前脚掌长、后脚掌长、前臂长、后臂长、大腿长、小腿长等体长数据。研究结果发现:1)猕猴海南亚种的体型明显小于位于更高纬度地区的川西亚种、福建亚种和指名亚种,也小于相近纬度的大陆猕猴,结果支持贝格曼法则和岛屿法则。2)猕猴海南亚种雄性的生长速度大于雌性,且前者体型显著大于后者。3)群大小对群内个体的体型无显著影响,无显著群间竞争。4)个体的体质量、头长、顶臀长随等级增加而增加,但是尾长、臂长、腿长和脚掌长与等级无显著相关关系。本文为探讨猕猴属的形态演化提供基础资料,同时也为濒危灵长类保护和管理提供科学依据。  相似文献   

7.
Foot placement strategy is an essential aspect in the study of movement involving full body displacement. To get beyond a qualitative analysis, this paper provides a foot placement classification and analysis method that can be used in sports, rehabilitation or ergonomics. The method is based on machine learning using a weighted k-nearest neighbors algorithm. The learning phase is performed by an observer who classifies a set of trials. The algorithm then automatically reproduces this classification on subsequent sets. The method also provides detailed analysis of foot placement strategy, such as estimating the average foot placements for each class or visualizing the variability of strategies. An example of applying the method to a manual material handling task demonstrates its usefulness. During the lifting phase, the foot placements were classified into four groups: front, contralateral foot behind, ipsilateral foot behind, and parallel. The accuracy of the classification, assessed with a holdout method, is about 97%. In this example, the classification method makes it possible to observe and analyze the handler’s foot placement strategies with regards to the performed task.  相似文献   

8.
We report a case of black grain mycetoma in a 74-years-old man who presented with a 50-yr. history of sinus-tract formation in the right foot. This is the first case of an Exophiala jeanselmeimycetoma successfully treated with itraconazole. In addition a review of the literature on this subject was done.  相似文献   

9.
Zoo animal collections have gone through a variety of changes in recent decades. While an increasing number of species may be establishing self-sustainable populations, early specimens of some animal groups were captured and transported in wasteful and unacceptable methods, a part of history that should not be forgotten. Selection of species has shifted from individual to group decision-making processes, reflecting a different type of personnel now in charge. The fact remains, however, that zoos continue to present a popularity-driven, skewed representation of the animal kingdom to the public. Wildlife conservation has been one of the main purposes for zoos as well as zoo associations, both in Europe and America. In actuality, the concept of conservation is subject to individual interpretation and this is where a clear definition of the zoos’ role could become rather vague. An important and worthwhile task for zoos is conservation education. To counteract deep-rooted anthropomorphism in the public's mind is not easy, yet it is a necessary step to raise citizens’ environmental awareness. The ultimate results of conservation education include changing daily habits, as well as participation in grass-roots conservation movements, by citizens.  相似文献   

10.
More has been written about the iconic Dodo Raphus cucullatus of Mauritius than any other extinct bird, yet despite its familiarity, only a few specimens were exported from Mauritius; individual birds reached Europe alive in 1626 and 1638 and at least two survived a journey to India in 1625. There are also vague records of other exported birds. Here, we provide confirmation based on seventeenth century documents that a live Dodo was sent to Japan in 1647, the last known captive bird, and comment on the details of its long and arduous voyage.  相似文献   

11.
When reaching for an object that unexpectedly moves, the hand is ‘magnetically’ drawn toward the object. This occurs even before the subject perceives object motion 1., 2., 3., possibly through sub-cortical visuo-motor processes [4]. Whether a similar process exists for the lower limb is open to question. The evolution of a rapid visuo-motor process has obvious advantages for the hand, for example for catching prey, but less obvious advantage for the foot. Rapid visual driving of the foot may even be hazardous because of the need to maintain balance: this is normally maintained during a step by a pre-step predictive throw of the body which is tightly coupled to intended future foot placement 5., 6.. Visually driven, mid-step deviations of the foot would upset this coupling and threaten balance. We ask whether the foot, like the hand, is automatically and rapidly driven by vision, and if so whether the process is suppressed by the balance constraint of stepping.  相似文献   

12.
We review the history of Quaternary pollen analysis from 1916 to the present-day, with particular emphasis on methodological and conceptual developments and on the early pioneers of the subject. The history is divided into three phases—the pioneer phase 1916–1950, the building phase 1951–1973, and the mature phase 1974–present-day. We also explore relevant studies prior to Lennart von Post’s seminal lecture in 1916 in Kristiania (Oslo) in an attempt to trace how the idea of Quaternary pollen analysis with quantitative pollen counting and stratigraphical pollen diagrams developed.  相似文献   

13.
BACKGROUND: Neck dissection has traditionally played an important role in the management of patients with regionally advanced head and neck squamous cell carcinoma (HNSCC) treated with radical radiotherapy alone. However, with the incorporation of chemotherapy in the therapeutic strategy for advanced HNSCC and resultant improvement in outcome the routine use of post chemo-radiotherapy neck dissection is being questioned. METHODS: Published data for this review was identified by systematically searching MEDLINE, CANCERLIT & EMBASE databases from 1995 until date with restriction to the English language. RESULTS: There is lack of high quality evidence on the role of planned neck dissection in advanced HNSCC treated with chemo-radiotherapy. A systematic literature search could identify only one small randomized controlled trial (Level I evidence) addressing this issue, albeit with major limitations. Upfront neck dissection followed by chemo-radiotherapy resulted in better disease-specific survival as compared to chemoradiation only. Several single arm prospective and retrospective reports were also identified with significant heterogeneity and often-contradictory conclusions. CONCLUSIONS: Planned neck dissection after radical chemo-radiotherapy achieves a high level of regional control, but its ultimate benefit is limited to a small subset of patients only. Unless there are better non-invasive ways to identify residual viable disease, the role of such neck dissection shall remain debatable. A large randomized controlled trial addressing this issue is needed to clarify its role and provide evidence-based answers.  相似文献   

14.
Summary A procedure is presented by which four previously described morphogenetic substances can be purified from hydra: an activator and an inhibitor of head formation and an activator and an inhibitor of foot formation. We show that all four substances act specifically. At low concentrations, the head factors only influence head and not foot formation, and the foot factors only influence foot and not head formation.  相似文献   

15.
The Cnidarian, hydra, is an appealing model system for studying the basic processes underlying pattern formation. Classical studies have elucidated much basic information regarding the role of development gradients, and theoretical models have been quite successful at describing experimental results. However, most experiments and computer simulations have dealt with isolated patterning events such as the dynamics of head regeneration. More global events such as interactions among the head, bud, and foot patterning systems have not been extensively addressed. The characterization of monoclonal antibodies with position-specific labeling patterns and the recent cloning and characterization of genes expressed in position-specific manners now provide the tools for investigating global interactions between patterning systems. In particular, changes in the axial positional value gradient may be monitored in response to experimental perturbation. Rather than studying isolated patterning events, this approach allows us to study patterning over the entire animal. The studies reported here focus on interactions between the foot and the head patterning systems in Hydra vulgaris following induction of a foot in close proximity to a head, axial grafting of a foot closer to the head, or doubling the amount of basal tissue by lateral grafting of an additional peduncle-foot onto host animals. Resulting positional value changes as monitored by antigen (TS19) and gene (ks1 and CnNK-2) expression were assessed in the foot, head, and intervening tissue. The results of the experiments indicate that positional values changed rapidly, in a matter of hours, and that there were reciprocal interactions between the foot and the head patterning systems. Theoretical interpretations of the results in the form of computer simulations based on the reaction-diffusion model are presented and predict many, but not all, of the experimental observations. Since the lateral grafting experiment cannot, at present, be simulated, it is discussed in light of what has been learned from the axial grafting experiments and their simulations.  相似文献   

16.
The head is kinematically constrained to the torso through the spine and thus, the spine dictates the amount of output head angular motion expected from an input impact. Here, we investigate the spinal kinematic constraint by analyzing the head instantaneous center of rotation (HICOR) with respect to the torso in head/neck sagittal extension and coronal lateral flexion during mild loads applied to 10 subjects. We found the mean HICOR location was near the C5-C6 intervertebral joint in sagittal extension, and T2-T3 intervertebral joint in coronal lateral flexion. Using the impulse-momentum relationship normalized by subject mass and neck length, we developed a non-dimensional analytical ratio between output angular velocity and input linear impulse as a function of HICOR location. The ratio was 0.65 and 0.50 in sagittal extension and coronal lateral flexion respectively, implying 30% greater angular velocities in sagittal extension given an equivalent impulse. Scaling to subject physiology also predicts larger required impulses given greater subject mass and neck length to achieve equivalent angular velocities, which was observed experimentally. Furthermore, the HICOR has greater motion in sagittal extension than coronal lateral flexion, suggesting the head and spine can be represented with a single inverted pendulum in coronal lateral flexion, but requires a more complex representation in sagittal extension. The upper cervical spine has substantial compliance in sagittal extension, and may be responsible for the complex motion and greater extension angular velocities. In analyzing the HICOR, we can gain intuition regarding the neck’s role in dictating head motion during external loading.  相似文献   

17.
An unbiased understanding of foot kinematics has been difficult to achieve due to the complexity of foot structure and motion. We have developed a protocol for evaluation of foot kinematics during barefoot walking based on a multi-segment foot model. Stereophotogrammetry was used to measure retroreflective markers on three segments of the foot plus the tibia. Repeatability was evaluated between-trial, between-day and between-tester using two subjects and two testers. Subtle patterns and ranges of motion between segments of the foot were consistently detected. We found that repeatability between different days or different testers is primarily subject to variability of marker placement more than inter-tester variability or skin movement. Differences between inter-segment angle curves primarily represent a shift in the absolute value of joint angles from one set of trials to another. In the hallux, variability was greater than desired due to vibration of the marker array used. The method permits objective foot measurement in gait analysis using skin-mounted markers. Quantitative and objective characterisation of the kinematics of the foot during activity is an important area of clinical and research evaluation. With this work we hope to have provided a firm basis for a common protocol for in vivo foot study.  相似文献   

18.
This essay examines how crime dramas produced during, and since, the 1990s became marked by the quest for ‘forensic realism’. In particular, the essay traces a landmark shift in the development of forensic realism in the form of the ground-breaking British police drama Prime Suspect in 1991. It is argued that this television series not only represents a turning point in television history, but that it also constitutes a key text in the broader cultural turn towards forensic fascination. Prime Suspect vividly revealed and displayed corpses, crime scenes and post-mortem photos in an unprecedented fashion for television. This essay shows how in the process it established new standards and expectations regarding the aesthetics and thematic content of the perceived ‘realism’ of the crime genre. Through an analysis of the reception and impact of Prime Suspect the essay also demonstrates how crime drama’s increasing fascination with forensic realism has driven debate over just what kinds of stories and images constitute acceptable or appropriate subject matter for popular entertainment, and for the medium of television itself.  相似文献   

19.
Evolutionary psychiatrists invariably consider schizophrenia to be a paradox: how come natural selection has not yet eliminated the infamous ‘genes for schizophrenia’ if the disorder simply crushes the reproductive success of its carriers, if it has been around for thousands of years already, and if it has a uniform prevalence throughout the world? Usually, the answer is that the schizophrenic genotype is subject to some kind of balancing selection: the benefits it confers would then outbalance the obvious damage it does. In this paper, however, I will show that the assumptions underlying such evolutionary accounts of schizophrenia are at least implausible, and sometimes even erroneous. First of all, I will examine some factual assumptions, in particular about schizophrenia’s impact on reproductive success, its genetics, its history, and its epidemiology. Secondly, I will take a critical look at a major philosophical assumption in evolutionary psychiatric explanations of schizophrenia. Indeed, evolutionary psychiatrists take it for granted that schizophrenia is a natural kind, i.e. a bounded and objectively real entity with discrete biological causes. My refutation of this natural kind view suggests that schizophrenia is in fact a reified umbrella concept, covering a heterogeneous group of disorders. Therefore, schizophrenia, as we now know it, simply doesn’t have an evolutionary history.  相似文献   

20.
Despite the amount of work that has been produced on the subject over the years, the ‘transformation of cladistics’ is still a misunderstood episode in the history of comparative biology. Here, I analyze two outstanding, highly contrasting historiographic accounts on the matter, under the perspective of an influential dichotomy in the philosophy of science: the opposition between Scientific Realism and Empiricism. Placing special emphasis on the notion of ‘causal grounding’ of morphological characters (sensu Olivier Rieppel) in modern developmental biology’s (mechanistic) theories, I arrive at the conclusion that a ‘new transformation of cladistics’ is philosophically plausible. This ‘reformed’ understanding of ‘pattern cladistics’ entails retaining the interpretation of cladograms as ‘schemes of synapomorphies’, but in association to construing cladogram nodes as ‘developmental-genetic taxic homologies’, instead of ‘standard Darwinian ancestors’. The reinterpretation of pattern cladistics presented here additionally proposes to take Bas Van Fraassen’s ‘constructive empiricism’ as a philosophical stance that could properly support such analysis of developmental-genetic data for systematic purposes. The latter suggestion is justified through a reappraisal of previous ideas developed by prominent pattern cladists (mainly, Colin Patterson), which concerned a scientifically efficient ‘observable/non-observable distinction’ linked to the conceptual pair ‘ontogeny and phylogeny’. Finally, I argue that a robust articulation of Antirealist alternatives in systematics may provide a rational basis for its disciplinary separation from evolutionary biology, as well as for a critical reconsideration of the proper role of certain Scientific Realist positions, currently popular in comparative biology.  相似文献   

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